| /* |
| * QEMU System Emulator block driver |
| * |
| * Copyright (c) 2003 Fabrice Bellard |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "block/trace.h" |
| #include "block/block_int.h" |
| #include "block/blockjob.h" |
| #include "block/nbd.h" |
| #include "block/qdict.h" |
| #include "qemu/error-report.h" |
| #include "module_block.h" |
| #include "qemu/main-loop.h" |
| #include "qemu/module.h" |
| #include "qapi/error.h" |
| #include "qapi/qmp/qdict.h" |
| #include "qapi/qmp/qjson.h" |
| #include "qapi/qmp/qnull.h" |
| #include "qapi/qmp/qstring.h" |
| #include "qapi/qobject-output-visitor.h" |
| #include "qapi/qapi-visit-block-core.h" |
| #include "sysemu/block-backend.h" |
| #include "sysemu/sysemu.h" |
| #include "qemu/notify.h" |
| #include "qemu/option.h" |
| #include "qemu/coroutine.h" |
| #include "block/qapi.h" |
| #include "qemu/timer.h" |
| #include "qemu/cutils.h" |
| #include "qemu/id.h" |
| |
| #ifdef CONFIG_BSD |
| #include <sys/ioctl.h> |
| #include <sys/queue.h> |
| #ifndef __DragonFly__ |
| #include <sys/disk.h> |
| #endif |
| #endif |
| |
| #ifdef _WIN32 |
| #include <windows.h> |
| #endif |
| |
| #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ |
| |
| static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states = |
| QTAILQ_HEAD_INITIALIZER(graph_bdrv_states); |
| |
| static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states = |
| QTAILQ_HEAD_INITIALIZER(all_bdrv_states); |
| |
| static QLIST_HEAD(, BlockDriver) bdrv_drivers = |
| QLIST_HEAD_INITIALIZER(bdrv_drivers); |
| |
| static BlockDriverState *bdrv_open_inherit(const char *filename, |
| const char *reference, |
| QDict *options, int flags, |
| BlockDriverState *parent, |
| const BdrvChildClass *child_class, |
| BdrvChildRole child_role, |
| Error **errp); |
| |
| /* If non-zero, use only whitelisted block drivers */ |
| static int use_bdrv_whitelist; |
| |
| #ifdef _WIN32 |
| static int is_windows_drive_prefix(const char *filename) |
| { |
| return (((filename[0] >= 'a' && filename[0] <= 'z') || |
| (filename[0] >= 'A' && filename[0] <= 'Z')) && |
| filename[1] == ':'); |
| } |
| |
| int is_windows_drive(const char *filename) |
| { |
| if (is_windows_drive_prefix(filename) && |
| filename[2] == '\0') |
| return 1; |
| if (strstart(filename, "\\\\.\\", NULL) || |
| strstart(filename, "//./", NULL)) |
| return 1; |
| return 0; |
| } |
| #endif |
| |
| size_t bdrv_opt_mem_align(BlockDriverState *bs) |
| { |
| if (!bs || !bs->drv) { |
| /* page size or 4k (hdd sector size) should be on the safe side */ |
| return MAX(4096, qemu_real_host_page_size); |
| } |
| |
| return bs->bl.opt_mem_alignment; |
| } |
| |
| size_t bdrv_min_mem_align(BlockDriverState *bs) |
| { |
| if (!bs || !bs->drv) { |
| /* page size or 4k (hdd sector size) should be on the safe side */ |
| return MAX(4096, qemu_real_host_page_size); |
| } |
| |
| return bs->bl.min_mem_alignment; |
| } |
| |
| /* check if the path starts with "<protocol>:" */ |
| int path_has_protocol(const char *path) |
| { |
| const char *p; |
| |
| #ifdef _WIN32 |
| if (is_windows_drive(path) || |
| is_windows_drive_prefix(path)) { |
| return 0; |
| } |
| p = path + strcspn(path, ":/\\"); |
| #else |
| p = path + strcspn(path, ":/"); |
| #endif |
| |
| return *p == ':'; |
| } |
| |
| int path_is_absolute(const char *path) |
| { |
| #ifdef _WIN32 |
| /* specific case for names like: "\\.\d:" */ |
| if (is_windows_drive(path) || is_windows_drive_prefix(path)) { |
| return 1; |
| } |
| return (*path == '/' || *path == '\\'); |
| #else |
| return (*path == '/'); |
| #endif |
| } |
| |
| /* if filename is absolute, just return its duplicate. Otherwise, build a |
| path to it by considering it is relative to base_path. URL are |
| supported. */ |
| char *path_combine(const char *base_path, const char *filename) |
| { |
| const char *protocol_stripped = NULL; |
| const char *p, *p1; |
| char *result; |
| int len; |
| |
| if (path_is_absolute(filename)) { |
| return g_strdup(filename); |
| } |
| |
| if (path_has_protocol(base_path)) { |
| protocol_stripped = strchr(base_path, ':'); |
| if (protocol_stripped) { |
| protocol_stripped++; |
| } |
| } |
| p = protocol_stripped ?: base_path; |
| |
| p1 = strrchr(base_path, '/'); |
| #ifdef _WIN32 |
| { |
| const char *p2; |
| p2 = strrchr(base_path, '\\'); |
| if (!p1 || p2 > p1) { |
| p1 = p2; |
| } |
| } |
| #endif |
| if (p1) { |
| p1++; |
| } else { |
| p1 = base_path; |
| } |
| if (p1 > p) { |
| p = p1; |
| } |
| len = p - base_path; |
| |
| result = g_malloc(len + strlen(filename) + 1); |
| memcpy(result, base_path, len); |
| strcpy(result + len, filename); |
| |
| return result; |
| } |
| |
| /* |
| * Helper function for bdrv_parse_filename() implementations to remove optional |
| * protocol prefixes (especially "file:") from a filename and for putting the |
| * stripped filename into the options QDict if there is such a prefix. |
| */ |
| void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, |
| QDict *options) |
| { |
| if (strstart(filename, prefix, &filename)) { |
| /* Stripping the explicit protocol prefix may result in a protocol |
| * prefix being (wrongly) detected (if the filename contains a colon) */ |
| if (path_has_protocol(filename)) { |
| QString *fat_filename; |
| |
| /* This means there is some colon before the first slash; therefore, |
| * this cannot be an absolute path */ |
| assert(!path_is_absolute(filename)); |
| |
| /* And we can thus fix the protocol detection issue by prefixing it |
| * by "./" */ |
| fat_filename = qstring_from_str("./"); |
| qstring_append(fat_filename, filename); |
| |
| assert(!path_has_protocol(qstring_get_str(fat_filename))); |
| |
| qdict_put(options, "filename", fat_filename); |
| } else { |
| /* If no protocol prefix was detected, we can use the shortened |
| * filename as-is */ |
| qdict_put_str(options, "filename", filename); |
| } |
| } |
| } |
| |
| |
| /* Returns whether the image file is opened as read-only. Note that this can |
| * return false and writing to the image file is still not possible because the |
| * image is inactivated. */ |
| bool bdrv_is_read_only(BlockDriverState *bs) |
| { |
| return bs->read_only; |
| } |
| |
| int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, |
| bool ignore_allow_rdw, Error **errp) |
| { |
| /* Do not set read_only if copy_on_read is enabled */ |
| if (bs->copy_on_read && read_only) { |
| error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled", |
| bdrv_get_device_or_node_name(bs)); |
| return -EINVAL; |
| } |
| |
| /* Do not clear read_only if it is prohibited */ |
| if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) && |
| !ignore_allow_rdw) |
| { |
| error_setg(errp, "Node '%s' is read only", |
| bdrv_get_device_or_node_name(bs)); |
| return -EPERM; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Called by a driver that can only provide a read-only image. |
| * |
| * Returns 0 if the node is already read-only or it could switch the node to |
| * read-only because BDRV_O_AUTO_RDONLY is set. |
| * |
| * Returns -EACCES if the node is read-write and BDRV_O_AUTO_RDONLY is not set |
| * or bdrv_can_set_read_only() forbids making the node read-only. If @errmsg |
| * is not NULL, it is used as the error message for the Error object. |
| */ |
| int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg, |
| Error **errp) |
| { |
| int ret = 0; |
| |
| if (!(bs->open_flags & BDRV_O_RDWR)) { |
| return 0; |
| } |
| if (!(bs->open_flags & BDRV_O_AUTO_RDONLY)) { |
| goto fail; |
| } |
| |
| ret = bdrv_can_set_read_only(bs, true, false, NULL); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| bs->read_only = true; |
| bs->open_flags &= ~BDRV_O_RDWR; |
| |
| return 0; |
| |
| fail: |
| error_setg(errp, "%s", errmsg ?: "Image is read-only"); |
| return -EACCES; |
| } |
| |
| /* |
| * If @backing is empty, this function returns NULL without setting |
| * @errp. In all other cases, NULL will only be returned with @errp |
| * set. |
| * |
| * Therefore, a return value of NULL without @errp set means that |
| * there is no backing file; if @errp is set, there is one but its |
| * absolute filename cannot be generated. |
| */ |
| char *bdrv_get_full_backing_filename_from_filename(const char *backed, |
| const char *backing, |
| Error **errp) |
| { |
| if (backing[0] == '\0') { |
| return NULL; |
| } else if (path_has_protocol(backing) || path_is_absolute(backing)) { |
| return g_strdup(backing); |
| } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) { |
| error_setg(errp, "Cannot use relative backing file names for '%s'", |
| backed); |
| return NULL; |
| } else { |
| return path_combine(backed, backing); |
| } |
| } |
| |
| /* |
| * If @filename is empty or NULL, this function returns NULL without |
| * setting @errp. In all other cases, NULL will only be returned with |
| * @errp set. |
| */ |
| static char *bdrv_make_absolute_filename(BlockDriverState *relative_to, |
| const char *filename, Error **errp) |
| { |
| char *dir, *full_name; |
| |
| if (!filename || filename[0] == '\0') { |
| return NULL; |
| } else if (path_has_protocol(filename) || path_is_absolute(filename)) { |
| return g_strdup(filename); |
| } |
| |
| dir = bdrv_dirname(relative_to, errp); |
| if (!dir) { |
| return NULL; |
| } |
| |
| full_name = g_strconcat(dir, filename, NULL); |
| g_free(dir); |
| return full_name; |
| } |
| |
| char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp) |
| { |
| return bdrv_make_absolute_filename(bs, bs->backing_file, errp); |
| } |
| |
| void bdrv_register(BlockDriver *bdrv) |
| { |
| assert(bdrv->format_name); |
| QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); |
| } |
| |
| BlockDriverState *bdrv_new(void) |
| { |
| BlockDriverState *bs; |
| int i; |
| |
| bs = g_new0(BlockDriverState, 1); |
| QLIST_INIT(&bs->dirty_bitmaps); |
| for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { |
| QLIST_INIT(&bs->op_blockers[i]); |
| } |
| notifier_with_return_list_init(&bs->before_write_notifiers); |
| qemu_co_mutex_init(&bs->reqs_lock); |
| qemu_mutex_init(&bs->dirty_bitmap_mutex); |
| bs->refcnt = 1; |
| bs->aio_context = qemu_get_aio_context(); |
| |
| qemu_co_queue_init(&bs->flush_queue); |
| |
| for (i = 0; i < bdrv_drain_all_count; i++) { |
| bdrv_drained_begin(bs); |
| } |
| |
| QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list); |
| |
| return bs; |
| } |
| |
| static BlockDriver *bdrv_do_find_format(const char *format_name) |
| { |
| BlockDriver *drv1; |
| |
| QLIST_FOREACH(drv1, &bdrv_drivers, list) { |
| if (!strcmp(drv1->format_name, format_name)) { |
| return drv1; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| BlockDriver *bdrv_find_format(const char *format_name) |
| { |
| BlockDriver *drv1; |
| int i; |
| |
| drv1 = bdrv_do_find_format(format_name); |
| if (drv1) { |
| return drv1; |
| } |
| |
| /* The driver isn't registered, maybe we need to load a module */ |
| for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { |
| if (!strcmp(block_driver_modules[i].format_name, format_name)) { |
| block_module_load_one(block_driver_modules[i].library_name); |
| break; |
| } |
| } |
| |
| return bdrv_do_find_format(format_name); |
| } |
| |
| static int bdrv_format_is_whitelisted(const char *format_name, bool read_only) |
| { |
| static const char *whitelist_rw[] = { |
| CONFIG_BDRV_RW_WHITELIST |
| }; |
| static const char *whitelist_ro[] = { |
| CONFIG_BDRV_RO_WHITELIST |
| }; |
| const char **p; |
| |
| if (!whitelist_rw[0] && !whitelist_ro[0]) { |
| return 1; /* no whitelist, anything goes */ |
| } |
| |
| for (p = whitelist_rw; *p; p++) { |
| if (!strcmp(format_name, *p)) { |
| return 1; |
| } |
| } |
| if (read_only) { |
| for (p = whitelist_ro; *p; p++) { |
| if (!strcmp(format_name, *p)) { |
| return 1; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) |
| { |
| return bdrv_format_is_whitelisted(drv->format_name, read_only); |
| } |
| |
| bool bdrv_uses_whitelist(void) |
| { |
| return use_bdrv_whitelist; |
| } |
| |
| typedef struct CreateCo { |
| BlockDriver *drv; |
| char *filename; |
| QemuOpts *opts; |
| int ret; |
| Error *err; |
| } CreateCo; |
| |
| static void coroutine_fn bdrv_create_co_entry(void *opaque) |
| { |
| Error *local_err = NULL; |
| int ret; |
| |
| CreateCo *cco = opaque; |
| assert(cco->drv); |
| |
| ret = cco->drv->bdrv_co_create_opts(cco->drv, |
| cco->filename, cco->opts, &local_err); |
| error_propagate(&cco->err, local_err); |
| cco->ret = ret; |
| } |
| |
| int bdrv_create(BlockDriver *drv, const char* filename, |
| QemuOpts *opts, Error **errp) |
| { |
| int ret; |
| |
| Coroutine *co; |
| CreateCo cco = { |
| .drv = drv, |
| .filename = g_strdup(filename), |
| .opts = opts, |
| .ret = NOT_DONE, |
| .err = NULL, |
| }; |
| |
| if (!drv->bdrv_co_create_opts) { |
| error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); |
| ret = -ENOTSUP; |
| goto out; |
| } |
| |
| if (qemu_in_coroutine()) { |
| /* Fast-path if already in coroutine context */ |
| bdrv_create_co_entry(&cco); |
| } else { |
| co = qemu_coroutine_create(bdrv_create_co_entry, &cco); |
| qemu_coroutine_enter(co); |
| while (cco.ret == NOT_DONE) { |
| aio_poll(qemu_get_aio_context(), true); |
| } |
| } |
| |
| ret = cco.ret; |
| if (ret < 0) { |
| if (cco.err) { |
| error_propagate(errp, cco.err); |
| } else { |
| error_setg_errno(errp, -ret, "Could not create image"); |
| } |
| } |
| |
| out: |
| g_free(cco.filename); |
| return ret; |
| } |
| |
| /** |
| * Helper function for bdrv_create_file_fallback(): Resize @blk to at |
| * least the given @minimum_size. |
| * |
| * On success, return @blk's actual length. |
| * Otherwise, return -errno. |
| */ |
| static int64_t create_file_fallback_truncate(BlockBackend *blk, |
| int64_t minimum_size, Error **errp) |
| { |
| Error *local_err = NULL; |
| int64_t size; |
| int ret; |
| |
| ret = blk_truncate(blk, minimum_size, false, PREALLOC_MODE_OFF, 0, |
| &local_err); |
| if (ret < 0 && ret != -ENOTSUP) { |
| error_propagate(errp, local_err); |
| return ret; |
| } |
| |
| size = blk_getlength(blk); |
| if (size < 0) { |
| error_free(local_err); |
| error_setg_errno(errp, -size, |
| "Failed to inquire the new image file's length"); |
| return size; |
| } |
| |
| if (size < minimum_size) { |
| /* Need to grow the image, but we failed to do that */ |
| error_propagate(errp, local_err); |
| return -ENOTSUP; |
| } |
| |
| error_free(local_err); |
| local_err = NULL; |
| |
| return size; |
| } |
| |
| /** |
| * Helper function for bdrv_create_file_fallback(): Zero the first |
| * sector to remove any potentially pre-existing image header. |
| */ |
| static int create_file_fallback_zero_first_sector(BlockBackend *blk, |
| int64_t current_size, |
| Error **errp) |
| { |
| int64_t bytes_to_clear; |
| int ret; |
| |
| bytes_to_clear = MIN(current_size, BDRV_SECTOR_SIZE); |
| if (bytes_to_clear) { |
| ret = blk_pwrite_zeroes(blk, 0, bytes_to_clear, BDRV_REQ_MAY_UNMAP); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, |
| "Failed to clear the new image's first sector"); |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * Simple implementation of bdrv_co_create_opts for protocol drivers |
| * which only support creation via opening a file |
| * (usually existing raw storage device) |
| */ |
| int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv, |
| const char *filename, |
| QemuOpts *opts, |
| Error **errp) |
| { |
| BlockBackend *blk; |
| QDict *options; |
| int64_t size = 0; |
| char *buf = NULL; |
| PreallocMode prealloc; |
| Error *local_err = NULL; |
| int ret; |
| |
| size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); |
| buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); |
| prealloc = qapi_enum_parse(&PreallocMode_lookup, buf, |
| PREALLOC_MODE_OFF, &local_err); |
| g_free(buf); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -EINVAL; |
| } |
| |
| if (prealloc != PREALLOC_MODE_OFF) { |
| error_setg(errp, "Unsupported preallocation mode '%s'", |
| PreallocMode_str(prealloc)); |
| return -ENOTSUP; |
| } |
| |
| options = qdict_new(); |
| qdict_put_str(options, "driver", drv->format_name); |
| |
| blk = blk_new_open(filename, NULL, options, |
| BDRV_O_RDWR | BDRV_O_RESIZE, errp); |
| if (!blk) { |
| error_prepend(errp, "Protocol driver '%s' does not support image " |
| "creation, and opening the image failed: ", |
| drv->format_name); |
| return -EINVAL; |
| } |
| |
| size = create_file_fallback_truncate(blk, size, errp); |
| if (size < 0) { |
| ret = size; |
| goto out; |
| } |
| |
| ret = create_file_fallback_zero_first_sector(blk, size, errp); |
| if (ret < 0) { |
| goto out; |
| } |
| |
| ret = 0; |
| out: |
| blk_unref(blk); |
| return ret; |
| } |
| |
| int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp) |
| { |
| BlockDriver *drv; |
| |
| drv = bdrv_find_protocol(filename, true, errp); |
| if (drv == NULL) { |
| return -ENOENT; |
| } |
| |
| return bdrv_create(drv, filename, opts, errp); |
| } |
| |
| int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp) |
| { |
| Error *local_err = NULL; |
| int ret; |
| |
| assert(bs != NULL); |
| |
| if (!bs->drv) { |
| error_setg(errp, "Block node '%s' is not opened", bs->filename); |
| return -ENOMEDIUM; |
| } |
| |
| if (!bs->drv->bdrv_co_delete_file) { |
| error_setg(errp, "Driver '%s' does not support image deletion", |
| bs->drv->format_name); |
| return -ENOTSUP; |
| } |
| |
| ret = bs->drv->bdrv_co_delete_file(bs, &local_err); |
| if (ret < 0) { |
| error_propagate(errp, local_err); |
| } |
| |
| return ret; |
| } |
| |
| /** |
| * Try to get @bs's logical and physical block size. |
| * On success, store them in @bsz struct and return 0. |
| * On failure return -errno. |
| * @bs must not be empty. |
| */ |
| int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz) |
| { |
| BlockDriver *drv = bs->drv; |
| |
| if (drv && drv->bdrv_probe_blocksizes) { |
| return drv->bdrv_probe_blocksizes(bs, bsz); |
| } else if (drv && drv->is_filter && bs->file) { |
| return bdrv_probe_blocksizes(bs->file->bs, bsz); |
| } |
| |
| return -ENOTSUP; |
| } |
| |
| /** |
| * Try to get @bs's geometry (cyls, heads, sectors). |
| * On success, store them in @geo struct and return 0. |
| * On failure return -errno. |
| * @bs must not be empty. |
| */ |
| int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo) |
| { |
| BlockDriver *drv = bs->drv; |
| |
| if (drv && drv->bdrv_probe_geometry) { |
| return drv->bdrv_probe_geometry(bs, geo); |
| } else if (drv && drv->is_filter && bs->file) { |
| return bdrv_probe_geometry(bs->file->bs, geo); |
| } |
| |
| return -ENOTSUP; |
| } |
| |
| /* |
| * Create a uniquely-named empty temporary file. |
| * Return 0 upon success, otherwise a negative errno value. |
| */ |
| int get_tmp_filename(char *filename, int size) |
| { |
| #ifdef _WIN32 |
| char temp_dir[MAX_PATH]; |
| /* GetTempFileName requires that its output buffer (4th param) |
| have length MAX_PATH or greater. */ |
| assert(size >= MAX_PATH); |
| return (GetTempPath(MAX_PATH, temp_dir) |
| && GetTempFileName(temp_dir, "qem", 0, filename) |
| ? 0 : -GetLastError()); |
| #else |
| int fd; |
| const char *tmpdir; |
| tmpdir = getenv("TMPDIR"); |
| if (!tmpdir) { |
| tmpdir = "/var/tmp"; |
| } |
| if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { |
| return -EOVERFLOW; |
| } |
| fd = mkstemp(filename); |
| if (fd < 0) { |
| return -errno; |
| } |
| if (close(fd) != 0) { |
| unlink(filename); |
| return -errno; |
| } |
| return 0; |
| #endif |
| } |
| |
| /* |
| * Detect host devices. By convention, /dev/cdrom[N] is always |
| * recognized as a host CDROM. |
| */ |
| static BlockDriver *find_hdev_driver(const char *filename) |
| { |
| int score_max = 0, score; |
| BlockDriver *drv = NULL, *d; |
| |
| QLIST_FOREACH(d, &bdrv_drivers, list) { |
| if (d->bdrv_probe_device) { |
| score = d->bdrv_probe_device(filename); |
| if (score > score_max) { |
| score_max = score; |
| drv = d; |
| } |
| } |
| } |
| |
| return drv; |
| } |
| |
| static BlockDriver *bdrv_do_find_protocol(const char *protocol) |
| { |
| BlockDriver *drv1; |
| |
| QLIST_FOREACH(drv1, &bdrv_drivers, list) { |
| if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) { |
| return drv1; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| BlockDriver *bdrv_find_protocol(const char *filename, |
| bool allow_protocol_prefix, |
| Error **errp) |
| { |
| BlockDriver *drv1; |
| char protocol[128]; |
| int len; |
| const char *p; |
| int i; |
| |
| /* TODO Drivers without bdrv_file_open must be specified explicitly */ |
| |
| /* |
| * XXX(hch): we really should not let host device detection |
| * override an explicit protocol specification, but moving this |
| * later breaks access to device names with colons in them. |
| * Thanks to the brain-dead persistent naming schemes on udev- |
| * based Linux systems those actually are quite common. |
| */ |
| drv1 = find_hdev_driver(filename); |
| if (drv1) { |
| return drv1; |
| } |
| |
| if (!path_has_protocol(filename) || !allow_protocol_prefix) { |
| return &bdrv_file; |
| } |
| |
| p = strchr(filename, ':'); |
| assert(p != NULL); |
| len = p - filename; |
| if (len > sizeof(protocol) - 1) |
| len = sizeof(protocol) - 1; |
| memcpy(protocol, filename, len); |
| protocol[len] = '\0'; |
| |
| drv1 = bdrv_do_find_protocol(protocol); |
| if (drv1) { |
| return drv1; |
| } |
| |
| for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { |
| if (block_driver_modules[i].protocol_name && |
| !strcmp(block_driver_modules[i].protocol_name, protocol)) { |
| block_module_load_one(block_driver_modules[i].library_name); |
| break; |
| } |
| } |
| |
| drv1 = bdrv_do_find_protocol(protocol); |
| if (!drv1) { |
| error_setg(errp, "Unknown protocol '%s'", protocol); |
| } |
| return drv1; |
| } |
| |
| /* |
| * Guess image format by probing its contents. |
| * This is not a good idea when your image is raw (CVE-2008-2004), but |
| * we do it anyway for backward compatibility. |
| * |
| * @buf contains the image's first @buf_size bytes. |
| * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE, |
| * but can be smaller if the image file is smaller) |
| * @filename is its filename. |
| * |
| * For all block drivers, call the bdrv_probe() method to get its |
| * probing score. |
| * Return the first block driver with the highest probing score. |
| */ |
| BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, |
| const char *filename) |
| { |
| int score_max = 0, score; |
| BlockDriver *drv = NULL, *d; |
| |
| QLIST_FOREACH(d, &bdrv_drivers, list) { |
| if (d->bdrv_probe) { |
| score = d->bdrv_probe(buf, buf_size, filename); |
| if (score > score_max) { |
| score_max = score; |
| drv = d; |
| } |
| } |
| } |
| |
| return drv; |
| } |
| |
| static int find_image_format(BlockBackend *file, const char *filename, |
| BlockDriver **pdrv, Error **errp) |
| { |
| BlockDriver *drv; |
| uint8_t buf[BLOCK_PROBE_BUF_SIZE]; |
| int ret = 0; |
| |
| /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ |
| if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) { |
| *pdrv = &bdrv_raw; |
| return ret; |
| } |
| |
| ret = blk_pread(file, 0, buf, sizeof(buf)); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Could not read image for determining its " |
| "format"); |
| *pdrv = NULL; |
| return ret; |
| } |
| |
| drv = bdrv_probe_all(buf, ret, filename); |
| if (!drv) { |
| error_setg(errp, "Could not determine image format: No compatible " |
| "driver found"); |
| ret = -ENOENT; |
| } |
| *pdrv = drv; |
| return ret; |
| } |
| |
| /** |
| * Set the current 'total_sectors' value |
| * Return 0 on success, -errno on error. |
| */ |
| int refresh_total_sectors(BlockDriverState *bs, int64_t hint) |
| { |
| BlockDriver *drv = bs->drv; |
| |
| if (!drv) { |
| return -ENOMEDIUM; |
| } |
| |
| /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ |
| if (bdrv_is_sg(bs)) |
| return 0; |
| |
| /* query actual device if possible, otherwise just trust the hint */ |
| if (drv->bdrv_getlength) { |
| int64_t length = drv->bdrv_getlength(bs); |
| if (length < 0) { |
| return length; |
| } |
| hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE); |
| } |
| |
| bs->total_sectors = hint; |
| return 0; |
| } |
| |
| /** |
| * Combines a QDict of new block driver @options with any missing options taken |
| * from @old_options, so that leaving out an option defaults to its old value. |
| */ |
| static void bdrv_join_options(BlockDriverState *bs, QDict *options, |
| QDict *old_options) |
| { |
| if (bs->drv && bs->drv->bdrv_join_options) { |
| bs->drv->bdrv_join_options(options, old_options); |
| } else { |
| qdict_join(options, old_options, false); |
| } |
| } |
| |
| static BlockdevDetectZeroesOptions bdrv_parse_detect_zeroes(QemuOpts *opts, |
| int open_flags, |
| Error **errp) |
| { |
| Error *local_err = NULL; |
| char *value = qemu_opt_get_del(opts, "detect-zeroes"); |
| BlockdevDetectZeroesOptions detect_zeroes = |
| qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup, value, |
| BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, &local_err); |
| g_free(value); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return detect_zeroes; |
| } |
| |
| if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP && |
| !(open_flags & BDRV_O_UNMAP)) |
| { |
| error_setg(errp, "setting detect-zeroes to unmap is not allowed " |
| "without setting discard operation to unmap"); |
| } |
| |
| return detect_zeroes; |
| } |
| |
| /** |
| * Set open flags for aio engine |
| * |
| * Return 0 on success, -1 if the engine specified is invalid |
| */ |
| int bdrv_parse_aio(const char *mode, int *flags) |
| { |
| if (!strcmp(mode, "threads")) { |
| /* do nothing, default */ |
| } else if (!strcmp(mode, "native")) { |
| *flags |= BDRV_O_NATIVE_AIO; |
| #ifdef CONFIG_LINUX_IO_URING |
| } else if (!strcmp(mode, "io_uring")) { |
| *flags |= BDRV_O_IO_URING; |
| #endif |
| } else { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * Set open flags for a given discard mode |
| * |
| * Return 0 on success, -1 if the discard mode was invalid. |
| */ |
| int bdrv_parse_discard_flags(const char *mode, int *flags) |
| { |
| *flags &= ~BDRV_O_UNMAP; |
| |
| if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { |
| /* do nothing */ |
| } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { |
| *flags |= BDRV_O_UNMAP; |
| } else { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * Set open flags for a given cache mode |
| * |
| * Return 0 on success, -1 if the cache mode was invalid. |
| */ |
| int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough) |
| { |
| *flags &= ~BDRV_O_CACHE_MASK; |
| |
| if (!strcmp(mode, "off") || !strcmp(mode, "none")) { |
| *writethrough = false; |
| *flags |= BDRV_O_NOCACHE; |
| } else if (!strcmp(mode, "directsync")) { |
| *writethrough = true; |
| *flags |= BDRV_O_NOCACHE; |
| } else if (!strcmp(mode, "writeback")) { |
| *writethrough = false; |
| } else if (!strcmp(mode, "unsafe")) { |
| *writethrough = false; |
| *flags |= BDRV_O_NO_FLUSH; |
| } else if (!strcmp(mode, "writethrough")) { |
| *writethrough = true; |
| } else { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| static char *bdrv_child_get_parent_desc(BdrvChild *c) |
| { |
| BlockDriverState *parent = c->opaque; |
| return g_strdup(bdrv_get_device_or_node_name(parent)); |
| } |
| |
| static void bdrv_child_cb_drained_begin(BdrvChild *child) |
| { |
| BlockDriverState *bs = child->opaque; |
| bdrv_do_drained_begin_quiesce(bs, NULL, false); |
| } |
| |
| static bool bdrv_child_cb_drained_poll(BdrvChild *child) |
| { |
| BlockDriverState *bs = child->opaque; |
| return bdrv_drain_poll(bs, false, NULL, false); |
| } |
| |
| static void bdrv_child_cb_drained_end(BdrvChild *child, |
| int *drained_end_counter) |
| { |
| BlockDriverState *bs = child->opaque; |
| bdrv_drained_end_no_poll(bs, drained_end_counter); |
| } |
| |
| static int bdrv_child_cb_inactivate(BdrvChild *child) |
| { |
| BlockDriverState *bs = child->opaque; |
| assert(bs->open_flags & BDRV_O_INACTIVE); |
| return 0; |
| } |
| |
| static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild *child, AioContext *ctx, |
| GSList **ignore, Error **errp) |
| { |
| BlockDriverState *bs = child->opaque; |
| return bdrv_can_set_aio_context(bs, ctx, ignore, errp); |
| } |
| |
| static void bdrv_child_cb_set_aio_ctx(BdrvChild *child, AioContext *ctx, |
| GSList **ignore) |
| { |
| BlockDriverState *bs = child->opaque; |
| return bdrv_set_aio_context_ignore(bs, ctx, ignore); |
| } |
| |
| /* |
| * Returns the options and flags that a temporary snapshot should get, based on |
| * the originally requested flags (the originally requested image will have |
| * flags like a backing file) |
| */ |
| static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options, |
| int parent_flags, QDict *parent_options) |
| { |
| *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY; |
| |
| /* For temporary files, unconditional cache=unsafe is fine */ |
| qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off"); |
| qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on"); |
| |
| /* Copy the read-only and discard options from the parent */ |
| qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); |
| qdict_copy_default(child_options, parent_options, BDRV_OPT_DISCARD); |
| |
| /* aio=native doesn't work for cache.direct=off, so disable it for the |
| * temporary snapshot */ |
| *child_flags &= ~BDRV_O_NATIVE_AIO; |
| } |
| |
| static void bdrv_backing_attach(BdrvChild *c) |
| { |
| BlockDriverState *parent = c->opaque; |
| BlockDriverState *backing_hd = c->bs; |
| |
| assert(!parent->backing_blocker); |
| error_setg(&parent->backing_blocker, |
| "node is used as backing hd of '%s'", |
| bdrv_get_device_or_node_name(parent)); |
| |
| bdrv_refresh_filename(backing_hd); |
| |
| parent->open_flags &= ~BDRV_O_NO_BACKING; |
| pstrcpy(parent->backing_file, sizeof(parent->backing_file), |
| backing_hd->filename); |
| pstrcpy(parent->backing_format, sizeof(parent->backing_format), |
| backing_hd->drv ? backing_hd->drv->format_name : ""); |
| |
| bdrv_op_block_all(backing_hd, parent->backing_blocker); |
| /* Otherwise we won't be able to commit or stream */ |
| bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, |
| parent->backing_blocker); |
| bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM, |
| parent->backing_blocker); |
| /* |
| * We do backup in 3 ways: |
| * 1. drive backup |
| * The target bs is new opened, and the source is top BDS |
| * 2. blockdev backup |
| * Both the source and the target are top BDSes. |
| * 3. internal backup(used for block replication) |
| * Both the source and the target are backing file |
| * |
| * In case 1 and 2, neither the source nor the target is the backing file. |
| * In case 3, we will block the top BDS, so there is only one block job |
| * for the top BDS and its backing chain. |
| */ |
| bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE, |
| parent->backing_blocker); |
| bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET, |
| parent->backing_blocker); |
| } |
| |
| static void bdrv_backing_detach(BdrvChild *c) |
| { |
| BlockDriverState *parent = c->opaque; |
| |
| assert(parent->backing_blocker); |
| bdrv_op_unblock_all(c->bs, parent->backing_blocker); |
| error_free(parent->backing_blocker); |
| parent->backing_blocker = NULL; |
| } |
| |
| static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base, |
| const char *filename, Error **errp) |
| { |
| BlockDriverState *parent = c->opaque; |
| bool read_only = bdrv_is_read_only(parent); |
| int ret; |
| |
| if (read_only) { |
| ret = bdrv_reopen_set_read_only(parent, false, errp); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| |
| ret = bdrv_change_backing_file(parent, filename, |
| base->drv ? base->drv->format_name : ""); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Could not update backing file link"); |
| } |
| |
| if (read_only) { |
| bdrv_reopen_set_read_only(parent, true, NULL); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Returns the options and flags that a generic child of a BDS should |
| * get, based on the given options and flags for the parent BDS. |
| */ |
| static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format, |
| int *child_flags, QDict *child_options, |
| int parent_flags, QDict *parent_options) |
| { |
| int flags = parent_flags; |
| |
| /* |
| * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL. |
| * Generally, the question to answer is: Should this child be |
| * format-probed by default? |
| */ |
| |
| /* |
| * Pure and non-filtered data children of non-format nodes should |
| * be probed by default (even when the node itself has BDRV_O_PROTOCOL |
| * set). This only affects a very limited set of drivers (namely |
| * quorum and blkverify when this comment was written). |
| * Force-clear BDRV_O_PROTOCOL then. |
| */ |
| if (!parent_is_format && |
| (role & BDRV_CHILD_DATA) && |
| !(role & (BDRV_CHILD_METADATA | BDRV_CHILD_FILTERED))) |
| { |
| flags &= ~BDRV_O_PROTOCOL; |
| } |
| |
| /* |
| * All children of format nodes (except for COW children) and all |
| * metadata children in general should never be format-probed. |
| * Force-set BDRV_O_PROTOCOL then. |
| */ |
| if ((parent_is_format && !(role & BDRV_CHILD_COW)) || |
| (role & BDRV_CHILD_METADATA)) |
| { |
| flags |= BDRV_O_PROTOCOL; |
| } |
| |
| /* |
| * If the cache mode isn't explicitly set, inherit direct and no-flush from |
| * the parent. |
| */ |
| qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); |
| qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); |
| qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); |
| |
| if (role & BDRV_CHILD_COW) { |
| /* backing files are opened read-only by default */ |
| qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on"); |
| qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off"); |
| } else { |
| /* Inherit the read-only option from the parent if it's not set */ |
| qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); |
| qdict_copy_default(child_options, parent_options, |
| BDRV_OPT_AUTO_READ_ONLY); |
| } |
| |
| /* |
| * bdrv_co_pdiscard() respects unmap policy for the parent, so we |
| * can default to enable it on lower layers regardless of the |
| * parent option. |
| */ |
| qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap"); |
| |
| /* Clear flags that only apply to the top layer */ |
| flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ); |
| |
| if (role & BDRV_CHILD_METADATA) { |
| flags &= ~BDRV_O_NO_IO; |
| } |
| if (role & BDRV_CHILD_COW) { |
| flags &= ~BDRV_O_TEMPORARY; |
| } |
| |
| *child_flags = flags; |
| } |
| |
| static void bdrv_child_cb_attach(BdrvChild *child) |
| { |
| BlockDriverState *bs = child->opaque; |
| |
| if (child->role & BDRV_CHILD_COW) { |
| bdrv_backing_attach(child); |
| } |
| |
| bdrv_apply_subtree_drain(child, bs); |
| } |
| |
| static void bdrv_child_cb_detach(BdrvChild *child) |
| { |
| BlockDriverState *bs = child->opaque; |
| |
| if (child->role & BDRV_CHILD_COW) { |
| bdrv_backing_detach(child); |
| } |
| |
| bdrv_unapply_subtree_drain(child, bs); |
| } |
| |
| static int bdrv_child_cb_update_filename(BdrvChild *c, BlockDriverState *base, |
| const char *filename, Error **errp) |
| { |
| if (c->role & BDRV_CHILD_COW) { |
| return bdrv_backing_update_filename(c, base, filename, errp); |
| } |
| return 0; |
| } |
| |
| const BdrvChildClass child_of_bds = { |
| .parent_is_bds = true, |
| .get_parent_desc = bdrv_child_get_parent_desc, |
| .inherit_options = bdrv_inherited_options, |
| .drained_begin = bdrv_child_cb_drained_begin, |
| .drained_poll = bdrv_child_cb_drained_poll, |
| .drained_end = bdrv_child_cb_drained_end, |
| .attach = bdrv_child_cb_attach, |
| .detach = bdrv_child_cb_detach, |
| .inactivate = bdrv_child_cb_inactivate, |
| .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, |
| .set_aio_ctx = bdrv_child_cb_set_aio_ctx, |
| .update_filename = bdrv_child_cb_update_filename, |
| }; |
| |
| static int bdrv_open_flags(BlockDriverState *bs, int flags) |
| { |
| int open_flags = flags; |
| |
| /* |
| * Clear flags that are internal to the block layer before opening the |
| * image. |
| */ |
| open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL); |
| |
| return open_flags; |
| } |
| |
| static void update_flags_from_options(int *flags, QemuOpts *opts) |
| { |
| *flags &= ~(BDRV_O_CACHE_MASK | BDRV_O_RDWR | BDRV_O_AUTO_RDONLY); |
| |
| if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) { |
| *flags |= BDRV_O_NO_FLUSH; |
| } |
| |
| if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_DIRECT, false)) { |
| *flags |= BDRV_O_NOCACHE; |
| } |
| |
| if (!qemu_opt_get_bool_del(opts, BDRV_OPT_READ_ONLY, false)) { |
| *flags |= BDRV_O_RDWR; |
| } |
| |
| if (qemu_opt_get_bool_del(opts, BDRV_OPT_AUTO_READ_ONLY, false)) { |
| *flags |= BDRV_O_AUTO_RDONLY; |
| } |
| } |
| |
| static void update_options_from_flags(QDict *options, int flags) |
| { |
| if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) { |
| qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE); |
| } |
| if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) { |
| qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH, |
| flags & BDRV_O_NO_FLUSH); |
| } |
| if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) { |
| qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR)); |
| } |
| if (!qdict_haskey(options, BDRV_OPT_AUTO_READ_ONLY)) { |
| qdict_put_bool(options, BDRV_OPT_AUTO_READ_ONLY, |
| flags & BDRV_O_AUTO_RDONLY); |
| } |
| } |
| |
| static void bdrv_assign_node_name(BlockDriverState *bs, |
| const char *node_name, |
| Error **errp) |
| { |
| char *gen_node_name = NULL; |
| |
| if (!node_name) { |
| node_name = gen_node_name = id_generate(ID_BLOCK); |
| } else if (!id_wellformed(node_name)) { |
| /* |
| * Check for empty string or invalid characters, but not if it is |
| * generated (generated names use characters not available to the user) |
| */ |
| error_setg(errp, "Invalid node name"); |
| return; |
| } |
| |
| /* takes care of avoiding namespaces collisions */ |
| if (blk_by_name(node_name)) { |
| error_setg(errp, "node-name=%s is conflicting with a device id", |
| node_name); |
| goto out; |
| } |
| |
| /* takes care of avoiding duplicates node names */ |
| if (bdrv_find_node(node_name)) { |
| error_setg(errp, "Duplicate node name"); |
| goto out; |
| } |
| |
| /* Make sure that the node name isn't truncated */ |
| if (strlen(node_name) >= sizeof(bs->node_name)) { |
| error_setg(errp, "Node name too long"); |
| goto out; |
| } |
| |
| /* copy node name into the bs and insert it into the graph list */ |
| pstrcpy(bs->node_name, sizeof(bs->node_name), node_name); |
| QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list); |
| out: |
| g_free(gen_node_name); |
| } |
| |
| static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, |
| const char *node_name, QDict *options, |
| int open_flags, Error **errp) |
| { |
| Error *local_err = NULL; |
| int i, ret; |
| |
| bdrv_assign_node_name(bs, node_name, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -EINVAL; |
| } |
| |
| bs->drv = drv; |
| bs->read_only = !(bs->open_flags & BDRV_O_RDWR); |
| bs->opaque = g_malloc0(drv->instance_size); |
| |
| if (drv->bdrv_file_open) { |
| assert(!drv->bdrv_needs_filename || bs->filename[0]); |
| ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); |
| } else if (drv->bdrv_open) { |
| ret = drv->bdrv_open(bs, options, open_flags, &local_err); |
| } else { |
| ret = 0; |
| } |
| |
| if (ret < 0) { |
| if (local_err) { |
| error_propagate(errp, local_err); |
| } else if (bs->filename[0]) { |
| error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); |
| } else { |
| error_setg_errno(errp, -ret, "Could not open image"); |
| } |
| goto open_failed; |
| } |
| |
| ret = refresh_total_sectors(bs, bs->total_sectors); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Could not refresh total sector count"); |
| return ret; |
| } |
| |
| bdrv_refresh_limits(bs, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -EINVAL; |
| } |
| |
| assert(bdrv_opt_mem_align(bs) != 0); |
| assert(bdrv_min_mem_align(bs) != 0); |
| assert(is_power_of_2(bs->bl.request_alignment)); |
| |
| for (i = 0; i < bs->quiesce_counter; i++) { |
| if (drv->bdrv_co_drain_begin) { |
| drv->bdrv_co_drain_begin(bs); |
| } |
| } |
| |
| return 0; |
| open_failed: |
| bs->drv = NULL; |
| if (bs->file != NULL) { |
| bdrv_unref_child(bs, bs->file); |
| bs->file = NULL; |
| } |
| g_free(bs->opaque); |
| bs->opaque = NULL; |
| return ret; |
| } |
| |
| BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name, |
| int flags, Error **errp) |
| { |
| BlockDriverState *bs; |
| int ret; |
| |
| bs = bdrv_new(); |
| bs->open_flags = flags; |
| bs->explicit_options = qdict_new(); |
| bs->options = qdict_new(); |
| bs->opaque = NULL; |
| |
| update_options_from_flags(bs->options, flags); |
| |
| ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp); |
| if (ret < 0) { |
| qobject_unref(bs->explicit_options); |
| bs->explicit_options = NULL; |
| qobject_unref(bs->options); |
| bs->options = NULL; |
| bdrv_unref(bs); |
| return NULL; |
| } |
| |
| return bs; |
| } |
| |
| QemuOptsList bdrv_runtime_opts = { |
| .name = "bdrv_common", |
| .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head), |
| .desc = { |
| { |
| .name = "node-name", |
| .type = QEMU_OPT_STRING, |
| .help = "Node name of the block device node", |
| }, |
| { |
| .name = "driver", |
| .type = QEMU_OPT_STRING, |
| .help = "Block driver to use for the node", |
| }, |
| { |
| .name = BDRV_OPT_CACHE_DIRECT, |
| .type = QEMU_OPT_BOOL, |
| .help = "Bypass software writeback cache on the host", |
| }, |
| { |
| .name = BDRV_OPT_CACHE_NO_FLUSH, |
| .type = QEMU_OPT_BOOL, |
| .help = "Ignore flush requests", |
| }, |
| { |
| .name = BDRV_OPT_READ_ONLY, |
| .type = QEMU_OPT_BOOL, |
| .help = "Node is opened in read-only mode", |
| }, |
| { |
| .name = BDRV_OPT_AUTO_READ_ONLY, |
| .type = QEMU_OPT_BOOL, |
| .help = "Node can become read-only if opening read-write fails", |
| }, |
| { |
| .name = "detect-zeroes", |
| .type = QEMU_OPT_STRING, |
| .help = "try to optimize zero writes (off, on, unmap)", |
| }, |
| { |
| .name = BDRV_OPT_DISCARD, |
| .type = QEMU_OPT_STRING, |
| .help = "discard operation (ignore/off, unmap/on)", |
| }, |
| { |
| .name = BDRV_OPT_FORCE_SHARE, |
| .type = QEMU_OPT_BOOL, |
| .help = "always accept other writers (default: off)", |
| }, |
| { /* end of list */ } |
| }, |
| }; |
| |
| QemuOptsList bdrv_create_opts_simple = { |
| .name = "simple-create-opts", |
| .head = QTAILQ_HEAD_INITIALIZER(bdrv_create_opts_simple.head), |
| .desc = { |
| { |
| .name = BLOCK_OPT_SIZE, |
| .type = QEMU_OPT_SIZE, |
| .help = "Virtual disk size" |
| }, |
| { |
| .name = BLOCK_OPT_PREALLOC, |
| .type = QEMU_OPT_STRING, |
| .help = "Preallocation mode (allowed values: off)" |
| }, |
| { /* end of list */ } |
| } |
| }; |
| |
| /* |
| * Common part for opening disk images and files |
| * |
| * Removes all processed options from *options. |
| */ |
| static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, |
| QDict *options, Error **errp) |
| { |
| int ret, open_flags; |
| const char *filename; |
| const char *driver_name = NULL; |
| const char *node_name = NULL; |
| const char *discard; |
| QemuOpts *opts; |
| BlockDriver *drv; |
| Error *local_err = NULL; |
| |
| assert(bs->file == NULL); |
| assert(options != NULL && bs->options != options); |
| |
| opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); |
| if (!qemu_opts_absorb_qdict(opts, options, errp)) { |
| ret = -EINVAL; |
| goto fail_opts; |
| } |
| |
| update_flags_from_options(&bs->open_flags, opts); |
| |
| driver_name = qemu_opt_get(opts, "driver"); |
| drv = bdrv_find_format(driver_name); |
| assert(drv != NULL); |
| |
| bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false); |
| |
| if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) { |
| error_setg(errp, |
| BDRV_OPT_FORCE_SHARE |
| "=on can only be used with read-only images"); |
| ret = -EINVAL; |
| goto fail_opts; |
| } |
| |
| if (file != NULL) { |
| bdrv_refresh_filename(blk_bs(file)); |
| filename = blk_bs(file)->filename; |
| } else { |
| /* |
| * Caution: while qdict_get_try_str() is fine, getting |
| * non-string types would require more care. When @options |
| * come from -blockdev or blockdev_add, its members are typed |
| * according to the QAPI schema, but when they come from |
| * -drive, they're all QString. |
| */ |
| filename = qdict_get_try_str(options, "filename"); |
| } |
| |
| if (drv->bdrv_needs_filename && (!filename || !filename[0])) { |
| error_setg(errp, "The '%s' block driver requires a file name", |
| drv->format_name); |
| ret = -EINVAL; |
| goto fail_opts; |
| } |
| |
| trace_bdrv_open_common(bs, filename ?: "", bs->open_flags, |
| drv->format_name); |
| |
| bs->read_only = !(bs->open_flags & BDRV_O_RDWR); |
| |
| if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { |
| if (!bs->read_only && bdrv_is_whitelisted(drv, true)) { |
| ret = bdrv_apply_auto_read_only(bs, NULL, NULL); |
| } else { |
| ret = -ENOTSUP; |
| } |
| if (ret < 0) { |
| error_setg(errp, |
| !bs->read_only && bdrv_is_whitelisted(drv, true) |
| ? "Driver '%s' can only be used for read-only devices" |
| : "Driver '%s' is not whitelisted", |
| drv->format_name); |
| goto fail_opts; |
| } |
| } |
| |
| /* bdrv_new() and bdrv_close() make it so */ |
| assert(atomic_read(&bs->copy_on_read) == 0); |
| |
| if (bs->open_flags & BDRV_O_COPY_ON_READ) { |
| if (!bs->read_only) { |
| bdrv_enable_copy_on_read(bs); |
| } else { |
| error_setg(errp, "Can't use copy-on-read on read-only device"); |
| ret = -EINVAL; |
| goto fail_opts; |
| } |
| } |
| |
| discard = qemu_opt_get(opts, BDRV_OPT_DISCARD); |
| if (discard != NULL) { |
| if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) { |
| error_setg(errp, "Invalid discard option"); |
| ret = -EINVAL; |
| goto fail_opts; |
| } |
| } |
| |
| bs->detect_zeroes = |
| bdrv_parse_detect_zeroes(opts, bs->open_flags, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| ret = -EINVAL; |
| goto fail_opts; |
| } |
| |
| if (filename != NULL) { |
| pstrcpy(bs->filename, sizeof(bs->filename), filename); |
| } else { |
| bs->filename[0] = '\0'; |
| } |
| pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename); |
| |
| /* Open the image, either directly or using a protocol */ |
| open_flags = bdrv_open_flags(bs, bs->open_flags); |
| node_name = qemu_opt_get(opts, "node-name"); |
| |
| assert(!drv->bdrv_file_open || file == NULL); |
| ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp); |
| if (ret < 0) { |
| goto fail_opts; |
| } |
| |
| qemu_opts_del(opts); |
| return 0; |
| |
| fail_opts: |
| qemu_opts_del(opts); |
| return ret; |
| } |
| |
| static QDict *parse_json_filename(const char *filename, Error **errp) |
| { |
| QObject *options_obj; |
| QDict *options; |
| int ret; |
| |
| ret = strstart(filename, "json:", &filename); |
| assert(ret); |
| |
| options_obj = qobject_from_json(filename, errp); |
| if (!options_obj) { |
| error_prepend(errp, "Could not parse the JSON options: "); |
| return NULL; |
| } |
| |
| options = qobject_to(QDict, options_obj); |
| if (!options) { |
| qobject_unref(options_obj); |
| error_setg(errp, "Invalid JSON object given"); |
| return NULL; |
| } |
| |
| qdict_flatten(options); |
| |
| return options; |
| } |
| |
| static void parse_json_protocol(QDict *options, const char **pfilename, |
| Error **errp) |
| { |
| QDict *json_options; |
| Error *local_err = NULL; |
| |
| /* Parse json: pseudo-protocol */ |
| if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) { |
| return; |
| } |
| |
| json_options = parse_json_filename(*pfilename, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return; |
| } |
| |
| /* Options given in the filename have lower priority than options |
| * specified directly */ |
| qdict_join(options, json_options, false); |
| qobject_unref(json_options); |
| *pfilename = NULL; |
| } |
| |
| /* |
| * Fills in default options for opening images and converts the legacy |
| * filename/flags pair to option QDict entries. |
| * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a |
| * block driver has been specified explicitly. |
| */ |
| static int bdrv_fill_options(QDict **options, const char *filename, |
| int *flags, Error **errp) |
| { |
| const char *drvname; |
| bool protocol = *flags & BDRV_O_PROTOCOL; |
| bool parse_filename = false; |
| BlockDriver *drv = NULL; |
| Error *local_err = NULL; |
| |
| /* |
| * Caution: while qdict_get_try_str() is fine, getting non-string |
| * types would require more care. When @options come from |
| * -blockdev or blockdev_add, its members are typed according to |
| * the QAPI schema, but when they come from -drive, they're all |
| * QString. |
| */ |
| drvname = qdict_get_try_str(*options, "driver"); |
| if (drvname) { |
| drv = bdrv_find_format(drvname); |
| if (!drv) { |
| error_setg(errp, "Unknown driver '%s'", drvname); |
| return -ENOENT; |
| } |
| /* If the user has explicitly specified the driver, this choice should |
| * override the BDRV_O_PROTOCOL flag */ |
| protocol = drv->bdrv_file_open; |
| } |
| |
| if (protocol) { |
| *flags |= BDRV_O_PROTOCOL; |
| } else { |
| *flags &= ~BDRV_O_PROTOCOL; |
| } |
| |
| /* Translate cache options from flags into options */ |
| update_options_from_flags(*options, *flags); |
| |
| /* Fetch the file name from the options QDict if necessary */ |
| if (protocol && filename) { |
| if (!qdict_haskey(*options, "filename")) { |
| qdict_put_str(*options, "filename", filename); |
| parse_filename = true; |
| } else { |
| error_setg(errp, "Can't specify 'file' and 'filename' options at " |
| "the same time"); |
| return -EINVAL; |
| } |
| } |
| |
| /* Find the right block driver */ |
| /* See cautionary note on accessing @options above */ |
| filename = qdict_get_try_str(*options, "filename"); |
| |
| if (!drvname && protocol) { |
| if (filename) { |
| drv = bdrv_find_protocol(filename, parse_filename, errp); |
| if (!drv) { |
| return -EINVAL; |
| } |
| |
| drvname = drv->format_name; |
| qdict_put_str(*options, "driver", drvname); |
| } else { |
| error_setg(errp, "Must specify either driver or file"); |
| return -EINVAL; |
| } |
| } |
| |
| assert(drv || !protocol); |
| |
| /* Driver-specific filename parsing */ |
| if (drv && drv->bdrv_parse_filename && parse_filename) { |
| drv->bdrv_parse_filename(filename, *options, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -EINVAL; |
| } |
| |
| if (!drv->bdrv_needs_filename) { |
| qdict_del(*options, "filename"); |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, |
| uint64_t perm, uint64_t shared, |
| GSList *ignore_children, |
| bool *tighten_restrictions, Error **errp); |
| static void bdrv_child_abort_perm_update(BdrvChild *c); |
| static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); |
| |
| typedef struct BlockReopenQueueEntry { |
| bool prepared; |
| bool perms_checked; |
| BDRVReopenState state; |
| QTAILQ_ENTRY(BlockReopenQueueEntry) entry; |
| } BlockReopenQueueEntry; |
| |
| /* |
| * Return the flags that @bs will have after the reopens in @q have |
| * successfully completed. If @q is NULL (or @bs is not contained in @q), |
| * return the current flags. |
| */ |
| static int bdrv_reopen_get_flags(BlockReopenQueue *q, BlockDriverState *bs) |
| { |
| BlockReopenQueueEntry *entry; |
| |
| if (q != NULL) { |
| QTAILQ_FOREACH(entry, q, entry) { |
| if (entry->state.bs == bs) { |
| return entry->state.flags; |
| } |
| } |
| } |
| |
| return bs->open_flags; |
| } |
| |
| /* Returns whether the image file can be written to after the reopen queue @q |
| * has been successfully applied, or right now if @q is NULL. */ |
| static bool bdrv_is_writable_after_reopen(BlockDriverState *bs, |
| BlockReopenQueue *q) |
| { |
| int flags = bdrv_reopen_get_flags(q, bs); |
| |
| return (flags & (BDRV_O_RDWR | BDRV_O_INACTIVE)) == BDRV_O_RDWR; |
| } |
| |
| /* |
| * Return whether the BDS can be written to. This is not necessarily |
| * the same as !bdrv_is_read_only(bs), as inactivated images may not |
| * be written to but do not count as read-only images. |
| */ |
| bool bdrv_is_writable(BlockDriverState *bs) |
| { |
| return bdrv_is_writable_after_reopen(bs, NULL); |
| } |
| |
| static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, |
| BdrvChild *c, BdrvChildRole role, |
| BlockReopenQueue *reopen_queue, |
| uint64_t parent_perm, uint64_t parent_shared, |
| uint64_t *nperm, uint64_t *nshared) |
| { |
| assert(bs->drv && bs->drv->bdrv_child_perm); |
| bs->drv->bdrv_child_perm(bs, c, role, reopen_queue, |
| parent_perm, parent_shared, |
| nperm, nshared); |
| /* TODO Take force_share from reopen_queue */ |
| if (child_bs && child_bs->force_share) { |
| *nshared = BLK_PERM_ALL; |
| } |
| } |
| |
| /* |
| * Check whether permissions on this node can be changed in a way that |
| * @cumulative_perms and @cumulative_shared_perms are the new cumulative |
| * permissions of all its parents. This involves checking whether all necessary |
| * permission changes to child nodes can be performed. |
| * |
| * Will set *tighten_restrictions to true if and only if new permissions have to |
| * be taken or currently shared permissions are to be unshared. Otherwise, |
| * errors are not fatal as long as the caller accepts that the restrictions |
| * remain tighter than they need to be. The caller still has to abort the |
| * transaction. |
| * @tighten_restrictions cannot be used together with @q: When reopening, we may |
| * encounter fatal errors even though no restrictions are to be tightened. For |
| * example, changing a node from RW to RO will fail if the WRITE permission is |
| * to be kept. |
| * |
| * A call to this function must always be followed by a call to bdrv_set_perm() |
| * or bdrv_abort_perm_update(). |
| */ |
| static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, |
| uint64_t cumulative_perms, |
| uint64_t cumulative_shared_perms, |
| GSList *ignore_children, |
| bool *tighten_restrictions, Error **errp) |
| { |
| BlockDriver *drv = bs->drv; |
| BdrvChild *c; |
| int ret; |
| |
| assert(!q || !tighten_restrictions); |
| |
| if (tighten_restrictions) { |
| uint64_t current_perms, current_shared; |
| uint64_t added_perms, removed_shared_perms; |
| |
| bdrv_get_cumulative_perm(bs, ¤t_perms, ¤t_shared); |
| |
| added_perms = cumulative_perms & ~current_perms; |
| removed_shared_perms = current_shared & ~cumulative_shared_perms; |
| |
| *tighten_restrictions = added_perms || removed_shared_perms; |
| } |
| |
| /* Write permissions never work with read-only images */ |
| if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) && |
| !bdrv_is_writable_after_reopen(bs, q)) |
| { |
| if (!bdrv_is_writable_after_reopen(bs, NULL)) { |
| error_setg(errp, "Block node is read-only"); |
| } else { |
| uint64_t current_perms, current_shared; |
| bdrv_get_cumulative_perm(bs, ¤t_perms, ¤t_shared); |
| if (current_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) { |
| error_setg(errp, "Cannot make block node read-only, there is " |
| "a writer on it"); |
| } else { |
| error_setg(errp, "Cannot make block node read-only and create " |
| "a writer on it"); |
| } |
| } |
| |
| return -EPERM; |
| } |
| |
| /* Check this node */ |
| if (!drv) { |
| return 0; |
| } |
| |
| if (drv->bdrv_check_perm) { |
| return drv->bdrv_check_perm(bs, cumulative_perms, |
| cumulative_shared_perms, errp); |
| } |
| |
| /* Drivers that never have children can omit .bdrv_child_perm() */ |
| if (!drv->bdrv_child_perm) { |
| assert(QLIST_EMPTY(&bs->children)); |
| return 0; |
| } |
| |
| /* Check all children */ |
| QLIST_FOREACH(c, &bs->children, next) { |
| uint64_t cur_perm, cur_shared; |
| bool child_tighten_restr; |
| |
| bdrv_child_perm(bs, c->bs, c, c->role, q, |
| cumulative_perms, cumulative_shared_perms, |
| &cur_perm, &cur_shared); |
| ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children, |
| tighten_restrictions ? &child_tighten_restr |
| : NULL, |
| errp); |
| if (tighten_restrictions) { |
| *tighten_restrictions |= child_tighten_restr; |
| } |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Notifies drivers that after a previous bdrv_check_perm() call, the |
| * permission update is not performed and any preparations made for it (e.g. |
| * taken file locks) need to be undone. |
| * |
| * This function recursively notifies all child nodes. |
| */ |
| static void bdrv_abort_perm_update(BlockDriverState *bs) |
| { |
| BlockDriver *drv = bs->drv; |
| BdrvChild *c; |
| |
| if (!drv) { |
| return; |
| } |
| |
| if (drv->bdrv_abort_perm_update) { |
| drv->bdrv_abort_perm_update(bs); |
| } |
| |
| QLIST_FOREACH(c, &bs->children, next) { |
| bdrv_child_abort_perm_update(c); |
| } |
| } |
| |
| static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms, |
| uint64_t cumulative_shared_perms) |
| { |
| BlockDriver *drv = bs->drv; |
| BdrvChild *c; |
| |
| if (!drv) { |
| return; |
| } |
| |
| /* Update this node */ |
| if (drv->bdrv_set_perm) { |
| drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms); |
| } |
| |
| /* Drivers that never have children can omit .bdrv_child_perm() */ |
| if (!drv->bdrv_child_perm) { |
| assert(QLIST_EMPTY(&bs->children)); |
| return; |
| } |
| |
| /* Update all children */ |
| QLIST_FOREACH(c, &bs->children, next) { |
| uint64_t cur_perm, cur_shared; |
| bdrv_child_perm(bs, c->bs, c, c->role, NULL, |
| cumulative_perms, cumulative_shared_perms, |
| &cur_perm, &cur_shared); |
| bdrv_child_set_perm(c, cur_perm, cur_shared); |
| } |
| } |
| |
| void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, |
| uint64_t *shared_perm) |
| { |
| BdrvChild *c; |
| uint64_t cumulative_perms = 0; |
| uint64_t cumulative_shared_perms = BLK_PERM_ALL; |
| |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| cumulative_perms |= c->perm; |
| cumulative_shared_perms &= c->shared_perm; |
| } |
| |
| *perm = cumulative_perms; |
| *shared_perm = cumulative_shared_perms; |
| } |
| |
| static char *bdrv_child_user_desc(BdrvChild *c) |
| { |
| if (c->klass->get_parent_desc) { |
| return c->klass->get_parent_desc(c); |
| } |
| |
| return g_strdup("another user"); |
| } |
| |
| char *bdrv_perm_names(uint64_t perm) |
| { |
| struct perm_name { |
| uint64_t perm; |
| const char *name; |
| } permissions[] = { |
| { BLK_PERM_CONSISTENT_READ, "consistent read" }, |
| { BLK_PERM_WRITE, "write" }, |
| { BLK_PERM_WRITE_UNCHANGED, "write unchanged" }, |
| { BLK_PERM_RESIZE, "resize" }, |
| { BLK_PERM_GRAPH_MOD, "change children" }, |
| { 0, NULL } |
| }; |
| |
| GString *result = g_string_sized_new(30); |
| struct perm_name *p; |
| |
| for (p = permissions; p->name; p++) { |
| if (perm & p->perm) { |
| if (result->len > 0) { |
| g_string_append(result, ", "); |
| } |
| g_string_append(result, p->name); |
| } |
| } |
| |
| return g_string_free(result, FALSE); |
| } |
| |
| /* |
| * Checks whether a new reference to @bs can be added if the new user requires |
| * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is |
| * set, the BdrvChild objects in this list are ignored in the calculations; |
| * this allows checking permission updates for an existing reference. |
| * |
| * See bdrv_check_perm() for the semantics of @tighten_restrictions. |
| * |
| * Needs to be followed by a call to either bdrv_set_perm() or |
| * bdrv_abort_perm_update(). */ |
| static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, |
| uint64_t new_used_perm, |
| uint64_t new_shared_perm, |
| GSList *ignore_children, |
| bool *tighten_restrictions, |
| Error **errp) |
| { |
| BdrvChild *c; |
| uint64_t cumulative_perms = new_used_perm; |
| uint64_t cumulative_shared_perms = new_shared_perm; |
| |
| assert(!q || !tighten_restrictions); |
| |
| /* There is no reason why anyone couldn't tolerate write_unchanged */ |
| assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED); |
| |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| if (g_slist_find(ignore_children, c)) { |
| continue; |
| } |
| |
| if ((new_used_perm & c->shared_perm) != new_used_perm) { |
| char *user = bdrv_child_user_desc(c); |
| char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm); |
| |
| if (tighten_restrictions) { |
| *tighten_restrictions = true; |
| } |
| |
| error_setg(errp, "Conflicts with use by %s as '%s', which does not " |
| "allow '%s' on %s", |
| user, c->name, perm_names, bdrv_get_node_name(c->bs)); |
| g_free(user); |
| g_free(perm_names); |
| return -EPERM; |
| } |
| |
| if ((c->perm & new_shared_perm) != c->perm) { |
| char *user = bdrv_child_user_desc(c); |
| char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm); |
| |
| if (tighten_restrictions) { |
| *tighten_restrictions = true; |
| } |
| |
| error_setg(errp, "Conflicts with use by %s as '%s', which uses " |
| "'%s' on %s", |
| user, c->name, perm_names, bdrv_get_node_name(c->bs)); |
| g_free(user); |
| g_free(perm_names); |
| return -EPERM; |
| } |
| |
| cumulative_perms |= c->perm; |
| cumulative_shared_perms &= c->shared_perm; |
| } |
| |
| return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, |
| ignore_children, tighten_restrictions, errp); |
| } |
| |
| /* Needs to be followed by a call to either bdrv_child_set_perm() or |
| * bdrv_child_abort_perm_update(). */ |
| static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, |
| uint64_t perm, uint64_t shared, |
| GSList *ignore_children, |
| bool *tighten_restrictions, Error **errp) |
| { |
| int ret; |
| |
| ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); |
| ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, |
| tighten_restrictions, errp); |
| g_slist_free(ignore_children); |
| |
| if (ret < 0) { |
| return ret; |
| } |
| |
| if (!c->has_backup_perm) { |
| c->has_backup_perm = true; |
| c->backup_perm = c->perm; |
| c->backup_shared_perm = c->shared_perm; |
| } |
| /* |
| * Note: it's OK if c->has_backup_perm was already set, as we can find the |
| * same child twice during check_perm procedure |
| */ |
| |
| c->perm = perm; |
| c->shared_perm = shared; |
| |
| return 0; |
| } |
| |
| static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) |
| { |
| uint64_t cumulative_perms, cumulative_shared_perms; |
| |
| c->has_backup_perm = false; |
| |
| c->perm = perm; |
| c->shared_perm = shared; |
| |
| bdrv_get_cumulative_perm(c->bs, &cumulative_perms, |
| &cumulative_shared_perms); |
| bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms); |
| } |
| |
| static void bdrv_child_abort_perm_update(BdrvChild *c) |
| { |
| if (c->has_backup_perm) { |
| c->perm = c->backup_perm; |
| c->shared_perm = c->backup_shared_perm; |
| c->has_backup_perm = false; |
| } |
| |
| bdrv_abort_perm_update(c->bs); |
| } |
| |
| int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, |
| Error **errp) |
| { |
| Error *local_err = NULL; |
| int ret; |
| bool tighten_restrictions; |
| |
| ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL, |
| &tighten_restrictions, &local_err); |
| if (ret < 0) { |
| bdrv_child_abort_perm_update(c); |
| if (tighten_restrictions) { |
| error_propagate(errp, local_err); |
| } else { |
| /* |
| * Our caller may intend to only loosen restrictions and |
| * does not expect this function to fail. Errors are not |
| * fatal in such a case, so we can just hide them from our |
| * caller. |
| */ |
| error_free(local_err); |
| ret = 0; |
| } |
| return ret; |
| } |
| |
| bdrv_child_set_perm(c, perm, shared); |
| |
| return 0; |
| } |
| |
| int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp) |
| { |
| uint64_t parent_perms, parent_shared; |
| uint64_t perms, shared; |
| |
| bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared); |
| bdrv_child_perm(bs, c->bs, c, c->role, NULL, |
| parent_perms, parent_shared, &perms, &shared); |
| |
| return bdrv_child_try_set_perm(c, perms, shared, errp); |
| } |
| |
| /* |
| * Default implementation for .bdrv_child_perm() for block filters: |
| * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the |
| * filtered child. |
| */ |
| static void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, |
| BdrvChildRole role, |
| BlockReopenQueue *reopen_queue, |
| uint64_t perm, uint64_t shared, |
| uint64_t *nperm, uint64_t *nshared) |
| { |
| *nperm = perm & DEFAULT_PERM_PASSTHROUGH; |
| *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; |
| } |
| |
| static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c, |
| BdrvChildRole role, |
| BlockReopenQueue *reopen_queue, |
| uint64_t perm, uint64_t shared, |
| uint64_t *nperm, uint64_t *nshared) |
| { |
| assert(role & BDRV_CHILD_COW); |
| |
| /* |
| * We want consistent read from backing files if the parent needs it. |
| * No other operations are performed on backing files. |
| */ |
| perm &= BLK_PERM_CONSISTENT_READ; |
| |
| /* |
| * If the parent can deal with changing data, we're okay with a |
| * writable and resizable backing file. |
| * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? |
| */ |
| if (shared & BLK_PERM_WRITE) { |
| shared = BLK_PERM_WRITE | BLK_PERM_RESIZE; |
| } else { |
| shared = 0; |
| } |
| |
| shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | |
| BLK_PERM_WRITE_UNCHANGED; |
| |
| if (bs->open_flags & BDRV_O_INACTIVE) { |
| shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE; |
| } |
| |
| *nperm = perm; |
| *nshared = shared; |
| } |
| |
| static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c, |
| BdrvChildRole role, |
| BlockReopenQueue *reopen_queue, |
| uint64_t perm, uint64_t shared, |
| uint64_t *nperm, uint64_t *nshared) |
| { |
| int flags; |
| |
| assert(role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA)); |
| |
| flags = bdrv_reopen_get_flags(reopen_queue, bs); |
| |
| /* |
| * Apart from the modifications below, the same permissions are |
| * forwarded and left alone as for filters |
| */ |
| bdrv_filter_default_perms(bs, c, role, reopen_queue, |
| perm, shared, &perm, &shared); |
| |
| if (role & BDRV_CHILD_METADATA) { |
| /* Format drivers may touch metadata even if the guest doesn't write */ |
| if (bdrv_is_writable_after_reopen(bs, reopen_queue)) { |
| perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE; |
| } |
| |
| /* |
| * bs->file always needs to be consistent because of the |
| * metadata. We can never allow other users to resize or write |
| * to it. |
| */ |
| if (!(flags & BDRV_O_NO_IO)) { |
| perm |= BLK_PERM_CONSISTENT_READ; |
| } |
| shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); |
| } |
| |
| if (role & BDRV_CHILD_DATA) { |
| /* |
| * Technically, everything in this block is a subset of the |
| * BDRV_CHILD_METADATA path taken above, and so this could |
| * be an "else if" branch. However, that is not obvious, and |
| * this function is not performance critical, therefore we let |
| * this be an independent "if". |
| */ |
| |
| /* |
| * We cannot allow other users to resize the file because the |
| * format driver might have some assumptions about the size |
| * (e.g. because it is stored in metadata, or because the file |
| * is split into fixed-size data files). |
| */ |
| shared &= ~BLK_PERM_RESIZE; |
| |
| /* |
| * WRITE_UNCHANGED often cannot be performed as such on the |
| * data file. For example, the qcow2 driver may still need to |
| * write copied clusters on copy-on-read. |
| */ |
| if (perm & BLK_PERM_WRITE_UNCHANGED) { |
| perm |= BLK_PERM_WRITE; |
| } |
| |
| /* |
| * If the data file is written to, the format driver may |
| * expect to be able to resize it by writing beyond the EOF. |
| */ |
| if (perm & BLK_PERM_WRITE) { |
| perm |= BLK_PERM_RESIZE; |
| } |
| } |
| |
| if (bs->open_flags & BDRV_O_INACTIVE) { |
| shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE; |
| } |
| |
| *nperm = perm; |
| *nshared = shared; |
| } |
| |
| void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c, |
| BdrvChildRole role, BlockReopenQueue *reopen_queue, |
| uint64_t perm, uint64_t shared, |
| uint64_t *nperm, uint64_t *nshared) |
| { |
| if (role & BDRV_CHILD_FILTERED) { |
| assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA | |
| BDRV_CHILD_COW))); |
| bdrv_filter_default_perms(bs, c, role, reopen_queue, |
| perm, shared, nperm, nshared); |
| } else if (role & BDRV_CHILD_COW) { |
| assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA))); |
| bdrv_default_perms_for_cow(bs, c, role, reopen_queue, |
| perm, shared, nperm, nshared); |
| } else if (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA)) { |
| bdrv_default_perms_for_storage(bs, c, role, reopen_queue, |
| perm, shared, nperm, nshared); |
| } else { |
| g_assert_not_reached(); |
| } |
| } |
| |
| uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm) |
| { |
| static const uint64_t permissions[] = { |
| [BLOCK_PERMISSION_CONSISTENT_READ] = BLK_PERM_CONSISTENT_READ, |
| [BLOCK_PERMISSION_WRITE] = BLK_PERM_WRITE, |
| [BLOCK_PERMISSION_WRITE_UNCHANGED] = BLK_PERM_WRITE_UNCHANGED, |
| [BLOCK_PERMISSION_RESIZE] = BLK_PERM_RESIZE, |
| [BLOCK_PERMISSION_GRAPH_MOD] = BLK_PERM_GRAPH_MOD, |
| }; |
| |
| QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions) != BLOCK_PERMISSION__MAX); |
| QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions) != BLK_PERM_ALL + 1); |
| |
| assert(qapi_perm < BLOCK_PERMISSION__MAX); |
| |
| return permissions[qapi_perm]; |
| } |
| |
| static void bdrv_replace_child_noperm(BdrvChild *child, |
| BlockDriverState *new_bs) |
| { |
| BlockDriverState *old_bs = child->bs; |
| int new_bs_quiesce_counter; |
| int drain_saldo; |
| |
| assert(!child->frozen); |
| |
| if (old_bs && new_bs) { |
| assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); |
| } |
| |
| new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0); |
| drain_saldo = new_bs_quiesce_counter - child->parent_quiesce_counter; |
| |
| /* |
| * If the new child node is drained but the old one was not, flush |
| * all outstanding requests to the old child node. |
| */ |
| while (drain_saldo > 0 && child->klass->drained_begin) { |
| bdrv_parent_drained_begin_single(child, true); |
| drain_saldo--; |
| } |
| |
| if (old_bs) { |
| /* Detach first so that the recursive drain sections coming from @child |
| * are already gone and we only end the drain sections that came from |
| * elsewhere. */ |
| if (child->klass->detach) { |
| child->klass->detach(child); |
| } |
| QLIST_REMOVE(child, next_parent); |
| } |
| |
| child->bs = new_bs; |
| |
| if (new_bs) { |
| QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); |
| |
| /* |
| * Detaching the old node may have led to the new node's |
| * quiesce_counter having been decreased. Not a problem, we |
| * just need to recognize this here and then invoke |
| * drained_end appropriately more often. |
| */ |
| assert(new_bs->quiesce_counter <= new_bs_quiesce_counter); |
| drain_saldo += new_bs->quiesce_counter - new_bs_quiesce_counter; |
| |
| /* Attach only after starting new drained sections, so that recursive |
| * drain sections coming from @child don't get an extra .drained_begin |
| * callback. */ |
| if (child->klass->attach) { |
| child->klass->attach(child); |
| } |
| } |
| |
| /* |
| * If the old child node was drained but the new one is not, allow |
| * requests to come in only after the new node has been attached. |
| */ |
| while (drain_saldo < 0 && child->klass->drained_end) { |
| bdrv_parent_drained_end_single(child); |
| drain_saldo++; |
| } |
| } |
| |
| /* |
| * Updates @child to change its reference to point to @new_bs, including |
| * checking and applying the necessary permisson updates both to the old node |
| * and to @new_bs. |
| * |
| * NULL is passed as @new_bs for removing the reference before freeing @child. |
| * |
| * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this |
| * function uses bdrv_set_perm() to update the permissions according to the new |
| * reference that @new_bs gets. |
| */ |
| static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) |
| { |
| BlockDriverState *old_bs = child->bs; |
| uint64_t perm, shared_perm; |
| |
| bdrv_replace_child_noperm(child, new_bs); |
| |
| /* |
| * Start with the new node's permissions. If @new_bs is a (direct |
| * or indirect) child of @old_bs, we must complete the permission |
| * update on @new_bs before we loosen the restrictions on @old_bs. |
| * Otherwise, bdrv_check_perm() on @old_bs would re-initiate |
| * updating the permissions of @new_bs, and thus not purely loosen |
| * restrictions. |
| */ |
| if (new_bs) { |
| bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); |
| bdrv_set_perm(new_bs, perm, shared_perm); |
| } |
| |
| if (old_bs) { |
| /* Update permissions for old node. This is guaranteed to succeed |
| * because we're just taking a parent away, so we're loosening |
| * restrictions. */ |
| bool tighten_restrictions; |
| int ret; |
| |
| bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm); |
| ret = bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL, |
| &tighten_restrictions, NULL); |
| assert(tighten_restrictions == false); |
| if (ret < 0) { |
| /* We only tried to loosen restrictions, so errors are not fatal */ |
| bdrv_abort_perm_update(old_bs); |
| } else { |
| bdrv_set_perm(old_bs, perm, shared_perm); |
| } |
| |
| /* When the parent requiring a non-default AioContext is removed, the |
| * node moves back to the main AioContext */ |
| bdrv_try_set_aio_context(old_bs, qemu_get_aio_context(), NULL); |
| } |
| } |
| |
| /* |
| * This function steals the reference to child_bs from the caller. |
| * That reference is later dropped by bdrv_root_unref_child(). |
| * |
| * On failure NULL is returned, errp is set and the reference to |
| * child_bs is also dropped. |
| * |
| * The caller must hold the AioContext lock @child_bs, but not that of @ctx |
| * (unless @child_bs is already in @ctx). |
| */ |
| BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, |
| const char *child_name, |
| const BdrvChildClass *child_class, |
| BdrvChildRole child_role, |
| AioContext *ctx, |
| uint64_t perm, uint64_t shared_perm, |
| void *opaque, Error **errp) |
| { |
| BdrvChild *child; |
| Error *local_err = NULL; |
| int ret; |
| |
| ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, NULL, |
| errp); |
| if (ret < 0) { |
| bdrv_abort_perm_update(child_bs); |
| bdrv_unref(child_bs); |
| return NULL; |
| } |
| |
| child = g_new(BdrvChild, 1); |
| *child = (BdrvChild) { |
| .bs = NULL, |
| .name = g_strdup(child_name), |
| .klass = child_class, |
| .role = child_role, |
| .perm = perm, |
| .shared_perm = shared_perm, |
| .opaque = opaque, |
| }; |
| |
| /* If the AioContexts don't match, first try to move the subtree of |
| * child_bs into the AioContext of the new parent. If this doesn't work, |
| * try moving the parent into the AioContext of child_bs instead. */ |
| if (bdrv_get_aio_context(child_bs) != ctx) { |
| ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err); |
| if (ret < 0 && child_class->can_set_aio_ctx) { |
| GSList *ignore = g_slist_prepend(NULL, child); |
| ctx = bdrv_get_aio_context(child_bs); |
| if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) { |
| error_free(local_err); |
| ret = 0; |
| g_slist_free(ignore); |
| ignore = g_slist_prepend(NULL, child); |
| child_class->set_aio_ctx(child, ctx, &ignore); |
| } |
| g_slist_free(ignore); |
| } |
| if (ret < 0) { |
| error_propagate(errp, local_err); |
| g_free(child); |
| bdrv_abort_perm_update(child_bs); |
| bdrv_unref(child_bs); |
| return NULL; |
| } |
| } |
| |
| /* This performs the matching bdrv_set_perm() for the above check. */ |
| bdrv_replace_child(child, child_bs); |
| |
| return child; |
| } |
| |
| /* |
| * This function transfers the reference to child_bs from the caller |
| * to parent_bs. That reference is later dropped by parent_bs on |
| * bdrv_close() or if someone calls bdrv_unref_child(). |
| * |
| * On failure NULL is returned, errp is set and the reference to |
| * child_bs is also dropped. |
| * |
| * If @parent_bs and @child_bs are in different AioContexts, the caller must |
| * hold the AioContext lock for @child_bs, but not for @parent_bs. |
| */ |
| BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, |
| BlockDriverState *child_bs, |
| const char *child_name, |
| const BdrvChildClass *child_class, |
| BdrvChildRole child_role, |
| Error **errp) |
| { |
| BdrvChild *child; |
| uint64_t perm, shared_perm; |
| |
| bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm); |
| |
| assert(parent_bs->drv); |
| bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL, |
| perm, shared_perm, &perm, &shared_perm); |
| |
| child = bdrv_root_attach_child(child_bs, child_name, child_class, |
| child_role, bdrv_get_aio_context(parent_bs), |
| perm, shared_perm, parent_bs, errp); |
| if (child == NULL) { |
| return NULL; |
| } |
| |
| QLIST_INSERT_HEAD(&parent_bs->children, child, next); |
| return child; |
| } |
| |
| static void bdrv_detach_child(BdrvChild *child) |
| { |
| QLIST_SAFE_REMOVE(child, next); |
| |
| bdrv_replace_child(child, NULL); |
| |
| g_free(child->name); |
| g_free(child); |
| } |
| |
| void bdrv_root_unref_child(BdrvChild *child) |
| { |
| BlockDriverState *child_bs; |
| |
| child_bs = child->bs; |
| bdrv_detach_child(child); |
| bdrv_unref(child_bs); |
| } |
| |
| /** |
| * Clear all inherits_from pointers from children and grandchildren of |
| * @root that point to @root, where necessary. |
| */ |
| static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child) |
| { |
| BdrvChild *c; |
| |
| if (child->bs->inherits_from == root) { |
| /* |
| * Remove inherits_from only when the last reference between root and |
| * child->bs goes away. |
| */ |
| QLIST_FOREACH(c, &root->children, next) { |
| if (c != child && c->bs == child->bs) { |
| break; |
| } |
| } |
| if (c == NULL) { |
| child->bs->inherits_from = NULL; |
| } |
| } |
| |
| QLIST_FOREACH(c, &child->bs->children, next) { |
| bdrv_unset_inherits_from(root, c); |
| } |
| } |
| |
| void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) |
| { |
| if (child == NULL) { |
| return; |
| } |
| |
| bdrv_unset_inherits_from(parent, child); |
| bdrv_root_unref_child(child); |
| } |
| |
| |
| static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load) |
| { |
| BdrvChild *c; |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| if (c->klass->change_media) { |
| c->klass->change_media(c, load); |
| } |
| } |
| } |
| |
| /* Return true if you can reach parent going through child->inherits_from |
| * recursively. If parent or child are NULL, return false */ |
| static bool bdrv_inherits_from_recursive(BlockDriverState *child, |
| BlockDriverState *parent) |
| { |
| while (child && child != parent) { |
| child = child->inherits_from; |
| } |
| |
| return child != NULL; |
| } |
| |
| /* |
| * Return the BdrvChildRole for @bs's backing child. bs->backing is |
| * mostly used for COW backing children (role = COW), but also for |
| * filtered children (role = FILTERED | PRIMARY). |
| */ |
| static BdrvChildRole bdrv_backing_role(BlockDriverState *bs) |
| { |
| if (bs->drv && bs->drv->is_filter) { |
| return BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY; |
| } else { |
| return BDRV_CHILD_COW; |
| } |
| } |
| |
| /* |
| * Sets the backing file link of a BDS. A new reference is created; callers |
| * which don't need their own reference any more must call bdrv_unref(). |
| */ |
| void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, |
| Error **errp) |
| { |
| bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) && |
| bdrv_inherits_from_recursive(backing_hd, bs); |
| |
| if (bdrv_is_backing_chain_frozen(bs, backing_bs(bs), errp)) { |
| return; |
| } |
| |
| if (backing_hd) { |
| bdrv_ref(backing_hd); |
| } |
| |
| if (bs->backing) { |
| bdrv_unref_child(bs, bs->backing); |
| bs->backing = NULL; |
| } |
| |
| if (!backing_hd) { |
| goto out; |
| } |
| |
| bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds, |
| bdrv_backing_role(bs), errp); |
| /* If backing_hd was already part of bs's backing chain, and |
| * inherits_from pointed recursively to bs then let's update it to |
| * point directly to bs (else it will become NULL). */ |
| if (bs->backing && update_inherits_from) { |
| backing_hd->inherits_from = bs; |
| } |
| |
| out: |
| bdrv_refresh_limits(bs, NULL); |
| } |
| |
| /* |
| * Opens the backing file for a BlockDriverState if not yet open |
| * |
| * bdref_key specifies the key for the image's BlockdevRef in the options QDict. |
| * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict |
| * itself, all options starting with "${bdref_key}." are considered part of the |
| * BlockdevRef. |
| * |
| * TODO Can this be unified with bdrv_open_image()? |
| */ |
| int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, |
| const char *bdref_key, Error **errp) |
| { |
| char *backing_filename = NULL; |
| char *bdref_key_dot; |
| const char *reference = NULL; |
| int ret = 0; |
| bool implicit_backing = false; |
| BlockDriverState *backing_hd; |
| QDict *options; |
| QDict *tmp_parent_options = NULL; |
| Error *local_err = NULL; |
| |
| if (bs->backing != NULL) { |
| goto free_exit; |
| } |
| |
| /* NULL means an empty set of options */ |
| if (parent_options == NULL) { |
| tmp_parent_options = qdict_new(); |
| parent_options = tmp_parent_options; |
| } |
| |
| bs->open_flags &= ~BDRV_O_NO_BACKING; |
| |
| bdref_key_dot = g_strdup_printf("%s.", bdref_key); |
| qdict_extract_subqdict(parent_options, &options, bdref_key_dot); |
| g_free(bdref_key_dot); |
| |
| /* |
| * Caution: while qdict_get_try_str() is fine, getting non-string |
| * types would require more care. When @parent_options come from |
| * -blockdev or blockdev_add, its members are typed according to |
| * the QAPI schema, but when they come from -drive, they're all |
| * QString. |
| */ |
| reference = qdict_get_try_str(parent_options, bdref_key); |
| if (reference || qdict_haskey(options, "file.filename")) { |
| /* keep backing_filename NULL */ |
| } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { |
| qobject_unref(options); |
| goto free_exit; |
| } else { |
| if (qdict_size(options) == 0) { |
| /* If the user specifies options that do not modify the |
| * backing file's behavior, we might still consider it the |
| * implicit backing file. But it's easier this way, and |
| * just specifying some of the backing BDS's options is |
| * only possible with -drive anyway (otherwise the QAPI |
| * schema forces the user to specify everything). */ |
| implicit_backing = !strcmp(bs->auto_backing_file, bs->backing_file); |
| } |
| |
| backing_filename = bdrv_get_full_backing_filename(bs, &local_err); |
| if (local_err) { |
| ret = -EINVAL; |
| error_propagate(errp, local_err); |
| qobject_unref(options); |
| goto free_exit; |
| } |
| } |
| |
| if (!bs->drv || !bs->drv->supports_backing) { |
| ret = -EINVAL; |
| error_setg(errp, "Driver doesn't support backing files"); |
| qobject_unref(options); |
| goto free_exit; |
| } |
| |
| if (!reference && |
| bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) { |
| qdict_put_str(options, "driver", bs->backing_format); |
| } |
| |
| backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs, |
| &child_of_bds, bdrv_backing_role(bs), errp); |
| if (!backing_hd) { |
| bs->open_flags |= BDRV_O_NO_BACKING; |
| error_prepend(errp, "Could not open backing file: "); |
| ret = -EINVAL; |
| goto free_exit; |
| } |
| |
| if (implicit_backing) { |
| bdrv_refresh_filename(backing_hd); |
| pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file), |
| backing_hd->filename); |
| } |
| |
| /* Hook up the backing file link; drop our reference, bs owns the |
| * backing_hd reference now */ |
| bdrv_set_backing_hd(bs, backing_hd, &local_err); |
| bdrv_unref(backing_hd); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| ret = -EINVAL; |
| goto free_exit; |
| } |
| |
| qdict_del(parent_options, bdref_key); |
| |
| free_exit: |
| g_free(backing_filename); |
| qobject_unref(tmp_parent_options); |
| return ret; |
| } |
| |
| static BlockDriverState * |
| bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key, |
| BlockDriverState *parent, const BdrvChildClass *child_class, |
| BdrvChildRole child_role, bool allow_none, Error **errp) |
| { |
| BlockDriverState *bs = NULL; |
| QDict *image_options; |
| char *bdref_key_dot; |
| const char *reference; |
| |
| assert(child_class != NULL); |
| |
| bdref_key_dot = g_strdup_printf("%s.", bdref_key); |
| qdict_extract_subqdict(options, &image_options, bdref_key_dot); |
| g_free(bdref_key_dot); |
| |
| /* |
| * Caution: while qdict_get_try_str() is fine, getting non-string |
| * types would require more care. When @options come from |
| * -blockdev or blockdev_add, its members are typed according to |
| * the QAPI schema, but when they come from -drive, they're all |
| * QString. |
| */ |
| reference = qdict_get_try_str(options, bdref_key); |
| if (!filename && !reference && !qdict_size(image_options)) { |
| if (!allow_none) { |
| error_setg(errp, "A block device must be specified for \"%s\"", |
| bdref_key); |
| } |
| qobject_unref(image_options); |
| goto done; |
| } |
| |
| bs = bdrv_open_inherit(filename, reference, image_options, 0, |
| parent, child_class, child_role, errp); |
| if (!bs) { |
| goto done; |
| } |
| |
| done: |
| qdict_del(options, bdref_key); |
| return bs; |
| } |
| |
| /* |
| * Opens a disk image whose options are given as BlockdevRef in another block |
| * device's options. |
| * |
| * If allow_none is true, no image will be opened if filename is false and no |
| * BlockdevRef is given. NULL will be returned, but errp remains unset. |
| * |
| * bdrev_key specifies the key for the image's BlockdevRef in the options QDict. |
| * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict |
| * itself, all options starting with "${bdref_key}." are considered part of the |
| * BlockdevRef. |
| * |
| * The BlockdevRef will be removed from the options QDict. |
| */ |
| BdrvChild *bdrv_open_child(const char *filename, |
| QDict *options, const char *bdref_key, |
| BlockDriverState *parent, |
| const BdrvChildClass *child_class, |
| BdrvChildRole child_role, |
| bool allow_none, Error **errp) |
| { |
| BlockDriverState *bs; |
| |
| bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_class, |
| child_role, allow_none, errp); |
| if (bs == NULL) { |
| return NULL; |
| } |
| |
| return bdrv_attach_child(parent, bs, bdref_key, child_class, child_role, |
| errp); |
| } |
| |
| /* |
| * TODO Future callers may need to specify parent/child_class in order for |
| * option inheritance to work. Existing callers use it for the root node. |
| */ |
| BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp) |
| { |
| BlockDriverState *bs = NULL; |
| QObject *obj = NULL; |
| QDict *qdict = NULL; |
| const char *reference = NULL; |
| Visitor *v = NULL; |
| |
| if (ref->type == QTYPE_QSTRING) { |
| reference = ref->u.reference; |
| } else { |
| BlockdevOptions *options = &ref->u.definition; |
| assert(ref->type == QTYPE_QDICT); |
| |
| v = qobject_output_visitor_new(&obj); |
| visit_type_BlockdevOptions(v, NULL, &options, &error_abort); |
| visit_complete(v, &obj); |
| |
| qdict = qobject_to(QDict, obj); |
| qdict_flatten(qdict); |
| |
| /* bdrv_open_inherit() defaults to the values in bdrv_flags (for |
| * compatibility with other callers) rather than what we want as the |
| * real defaults. Apply the defaults here instead. */ |
| qdict_set_default_str(qdict, BDRV_OPT_CACHE_DIRECT, "off"); |
| qdict_set_default_str(qdict, BDRV_OPT_CACHE_NO_FLUSH, "off"); |
| qdict_set_default_str(qdict, BDRV_OPT_READ_ONLY, "off"); |
| qdict_set_default_str(qdict, BDRV_OPT_AUTO_READ_ONLY, "off"); |
| |
| } |
| |
| bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, 0, errp); |
| obj = NULL; |
| qobject_unref(obj); |
| visit_free(v); |
| return bs; |
| } |
| |
| static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs, |
| int flags, |
| QDict *snapshot_options, |
| Error **errp) |
| { |
| /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ |
| char *tmp_filename = g_malloc0(PATH_MAX + 1); |
| int64_t total_size; |
| QemuOpts *opts = NULL; |
| BlockDriverState *bs_snapshot = NULL; |
| Error *local_err = NULL; |
| int ret; |
| |
| /* if snapshot, we create a temporary backing file and open it |
| instead of opening 'filename' directly */ |
| |
| /* Get the required size from the image */ |
| total_size = bdrv_getlength(bs); |
| if (total_size < 0) { |
| error_setg_errno(errp, -total_size, "Could not get image size"); |
| goto out; |
| } |
| |
| /* Create the temporary image */ |
| ret = get_tmp_filename(tmp_filename, PATH_MAX + 1); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Could not get temporary filename"); |
| goto out; |
| } |
| |
| opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0, |
| &error_abort); |
| qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort); |
| ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp); |
| qemu_opts_del(opts); |
| if (ret < 0) { |
| error_prepend(errp, "Could not create temporary overlay '%s': ", |
| tmp_filename); |
| goto out; |
| } |
| |
| /* Prepare options QDict for the temporary file */ |
| qdict_put_str(snapshot_options, "file.driver", "file"); |
| qdict_put_str(snapshot_options, "file.filename", tmp_filename); |
| qdict_put_str(snapshot_options, "driver", "qcow2"); |
| |
| bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp); |
| snapshot_options = NULL; |
| if (!bs_snapshot) { |
| goto out; |
| } |
| |
| /* bdrv_append() consumes a strong reference to bs_snapshot |
| * (i.e. it will call bdrv_unref() on it) even on error, so in |
| * order to be able to return one, we have to increase |
| * bs_snapshot's refcount here */ |
| bdrv_ref(bs_snapshot); |
| bdrv_append(bs_snapshot, bs, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| bs_snapshot = NULL; |
| goto out; |
| } |
| |
| out: |
| qobject_unref(snapshot_options); |
| g_free(tmp_filename); |
| return bs_snapshot; |
| } |
| |
| /* |
| * Opens a disk image (raw, qcow2, vmdk, ...) |
| * |
| * options is a QDict of options to pass to the block drivers, or NULL for an |
| * empty set of options. The reference to the QDict belongs to the block layer |
| * after the call (even on failure), so if the caller intends to reuse the |
| * dictionary, it needs to use qobject_ref() before calling bdrv_open. |
| * |
| * If *pbs is NULL, a new BDS will be created with a pointer to it stored there. |
| * If it is not NULL, the referenced BDS will be reused. |
| * |
| * The reference parameter may be used to specify an existing block device which |
| * should be opened. If specified, neither options nor a filename may be given, |
| * nor can an existing BDS be reused (that is, *pbs has to be NULL). |
| */ |
| static BlockDriverState *bdrv_open_inherit(const char *filename, |
| const char *reference, |
| QDict *options, int flags, |
| BlockDriverState *parent, |
| const BdrvChildClass *child_class, |
| BdrvChildRole child_role, |
| Error **errp) |
| { |
| int ret; |
| BlockBackend *file = NULL; |
| BlockDriverState *bs; |
| BlockDriver *drv = NULL; |
| BdrvChild *child; |
| const char *drvname; |
| const char *backing; |
| Error *local_err = NULL; |
| QDict *snapshot_options = NULL; |
| int snapshot_flags = 0; |
| |
| assert(!child_class || !flags); |
| assert(!child_class == !parent); |
| |
| if (reference) { |
| bool options_non_empty = options ? qdict_size(options) : false; |
| qobject_unref(options); |
| |
| if (filename || options_non_empty) { |
| error_setg(errp, "Cannot reference an existing block device with " |
| "additional options or a new filename"); |
| return NULL; |
| } |
| |
| bs = bdrv_lookup_bs(reference, reference, errp); |
| if (!bs) { |
| return NULL; |
| } |
| |
| bdrv_ref(bs); |
| return bs; |
| } |
| |
| bs = bdrv_new(); |
| |
| /* NULL means an empty set of options */ |
| if (options == NULL) { |
| options = qdict_new(); |
| } |
| |
| /* json: syntax counts as explicit options, as if in the QDict */ |
| parse_json_protocol(options, &filename, &local_err); |
| if (local_err) { |
| goto fail; |
| } |
| |
| bs->explicit_options = qdict_clone_shallow(options); |
| |
| if (child_class) { |
| bool parent_is_format; |
| |
| if (parent->drv) { |
| parent_is_format = parent->drv->is_format; |
| } else { |
| /* |
| * parent->drv is not set yet because this node is opened for |
| * (potential) format probing. That means that @parent is going |
| * to be a format node. |
| */ |
| parent_is_format = true; |
| } |
| |
| bs->inherits_from = parent; |
| child_class->inherit_options(child_role, parent_is_format, |
| &flags, options, |
| parent->open_flags, parent->options); |
| } |
| |
| ret = bdrv_fill_options(&options, filename, &flags, &local_err); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* |
| * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags. |
| * Caution: getting a boolean member of @options requires care. |
| * When @options come from -blockdev or blockdev_add, members are |
| * typed according to the QAPI schema, but when they come from |
| * -drive, they're all QString. |
| */ |
| if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") && |
| !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) { |
| flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR); |
| } else { |
| flags &= ~BDRV_O_RDWR; |
| } |
| |
| if (flags & BDRV_O_SNAPSHOT) { |
| snapshot_options = qdict_new(); |
| bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options, |
| flags, options); |
| /* Let bdrv_backing_options() override "read-only" */ |
| qdict_del(options, BDRV_OPT_READ_ONLY); |
| bdrv_inherited_options(BDRV_CHILD_COW, true, |
| &flags, options, flags, options); |
| } |
| |
| bs->open_flags = flags; |
| bs->options = options; |
| options = qdict_clone_shallow(options); |
| |
| /* Find the right image format driver */ |
| /* See cautionary note on accessing @options above */ |
| drvname = qdict_get_try_str(options, "driver"); |
| if (drvname) { |
| drv = bdrv_find_format(drvname); |
| if (!drv) { |
| error_setg(errp, "Unknown driver: '%s'", drvname); |
| goto fail; |
| } |
| } |
| |
| assert(drvname || !(flags & BDRV_O_PROTOCOL)); |
| |
| /* See cautionary note on accessing @options above */ |
| backing = qdict_get_try_str(options, "backing"); |
| if (qobject_to(QNull, qdict_get(options, "backing")) != NULL || |
| (backing && *backing == '\0')) |
| { |
| if (backing) { |
| warn_report("Use of \"backing\": \"\" is deprecated; " |
| "use \"backing\": null instead"); |
| } |
| flags |= BDRV_O_NO_BACKING; |
| qdict_del(bs->explicit_options, "backing"); |
| qdict_del(bs->options, "backing"); |
| qdict_del(options, "backing"); |
| } |
| |
| /* Open image file without format layer. This BlockBackend is only used for |
| * probing, the block drivers will do their own bdrv_open_child() for the |
| * same BDS, which is why we put the node name back into options. */ |
| if ((flags & BDRV_O_PROTOCOL) == 0) { |
| BlockDriverState *file_bs; |
| |
| file_bs = bdrv_open_child_bs(filename, options, "file", bs, |
| &child_of_bds, BDRV_CHILD_IMAGE, |
| true, &local_err); |
| if (local_err) { |
| goto fail; |
| } |
| if (file_bs != NULL) { |
| /* Not requesting BLK_PERM_CONSISTENT_READ because we're only |
| * looking at the header to guess the image format. This works even |
| * in cases where a guest would not see a consistent state. */ |
| file = blk_new(bdrv_get_aio_context(file_bs), 0, BLK_PERM_ALL); |
| blk_insert_bs(file, file_bs, &local_err); |
| bdrv_unref(file_bs); |
| if (local_err) { |
| goto fail; |
| } |
| |
| qdict_put_str(options, "file", bdrv_get_node_name(file_bs)); |
| } |
| } |
| |
| /* Image format probing */ |
| bs->probed = !drv; |
| if (!drv && file) { |
| ret = find_image_format(file, filename, &drv, &local_err); |
| if (ret < 0) { |
| goto fail; |
| } |
| /* |
| * This option update would logically belong in bdrv_fill_options(), |
| * but we first need to open bs->file for the probing to work, while |
| * opening bs->file already requires the (mostly) final set of options |
| * so that cache mode etc. can be inherited. |
| * |
| * Adding the driver later is somewhat ugly, but it's not an option |
| * that would ever be inherited, so it's correct. We just need to make |
| * sure to update both bs->options (which has the full effective |
| * options for bs) and options (which has file.* already removed). |
| */ |
| qdict_put_str(bs->options, "driver", drv->format_name); |
| qdict_put_str(options, "driver", drv->format_name); |
| } else if (!drv) { |
| error_setg(errp, "Must specify either driver or file"); |
| goto fail; |
| } |
| |
| /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */ |
| assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open); |
| /* file must be NULL if a protocol BDS is about to be created |
| * (the inverse results in an error message from bdrv_open_common()) */ |
| assert(!(flags & BDRV_O_PROTOCOL) || !file); |
| |
| /* Open the image */ |
| ret = bdrv_open_common(bs, file, options, &local_err); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| if (file) { |
| blk_unref(file); |
| file = NULL; |
| } |
| |
| /* If there is a backing file, use it */ |
| if ((flags & BDRV_O_NO_BACKING) == 0) { |
| ret = bdrv_open_backing_file(bs, options, "backing", &local_err); |
| if (ret < 0) { |
| goto close_and_fail; |
| } |
| } |
| |
| /* Remove all children options and references |
| * from bs->options and bs->explicit_options */ |
| QLIST_FOREACH(child, &bs->children, next) { |
| char *child_key_dot; |
| child_key_dot = g_strdup_printf("%s.", child->name); |
| qdict_extract_subqdict(bs->explicit_options, NULL, child_key_dot); |
| qdict_extract_subqdict(bs->options, NULL, child_key_dot); |
| qdict_del(bs->explicit_options, child->name); |
| qdict_del(bs->options, child->name); |
| g_free(child_key_dot); |
| } |
| |
| /* Check if any unknown options were used */ |
| if (qdict_size(options) != 0) { |
| const QDictEntry *entry = qdict_first(options); |
| if (flags & BDRV_O_PROTOCOL) { |
| error_setg(errp, "Block protocol '%s' doesn't support the option " |
| "'%s'", drv->format_name, entry->key); |
| } else { |
| error_setg(errp, |
| "Block format '%s' does not support the option '%s'", |
| drv->format_name, entry->key); |
| } |
| |
| goto close_and_fail; |
| } |
| |
| bdrv_parent_cb_change_media(bs, true); |
| |
| qobject_unref(options); |
| options = NULL; |
| |
| /* For snapshot=on, create a temporary qcow2 overlay. bs points to the |
| * temporary snapshot afterwards. */ |
| if (snapshot_flags) { |
| BlockDriverState *snapshot_bs; |
| snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags, |
| snapshot_options, &local_err); |
| snapshot_options = NULL; |
| if (local_err) { |
| goto close_and_fail; |
| } |
| /* We are not going to return bs but the overlay on top of it |
| * (snapshot_bs); thus, we have to drop the strong reference to bs |
| * (which we obtained by calling bdrv_new()). bs will not be deleted, |
| * though, because the overlay still has a reference to it. */ |
| bdrv_unref(bs); |
| bs = snapshot_bs; |
| } |
| |
| return bs; |
| |
| fail: |
| blk_unref(file); |
| qobject_unref(snapshot_options); |
| qobject_unref(bs->explicit_options); |
| qobject_unref(bs->options); |
| qobject_unref(options); |
| bs->options = NULL; |
| bs->explicit_options = NULL; |
| bdrv_unref(bs); |
| error_propagate(errp, local_err); |
| return NULL; |
| |
| close_and_fail: |
| bdrv_unref(bs); |
| qobject_unref(snapshot_options); |
| qobject_unref(options); |
| error_propagate(errp, local_err); |
| return NULL; |
| } |
| |
| BlockDriverState *bdrv_open(const char *filename, const char *reference, |
| QDict *options, int flags, Error **errp) |
| { |
| return bdrv_open_inherit(filename, reference, options, flags, NULL, |
| NULL, 0, errp); |
| } |
| |
| /* Return true if the NULL-terminated @list contains @str */ |
| static bool is_str_in_list(const char *str, const char *const *list) |
| { |
| if (str && list) { |
| int i; |
| for (i = 0; list[i] != NULL; i++) { |
| if (!strcmp(str, list[i])) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| /* |
| * Check that every option set in @bs->options is also set in |
| * @new_opts. |
| * |
| * Options listed in the common_options list and in |
| * @bs->drv->mutable_opts are skipped. |
| * |
| * Return 0 on success, otherwise return -EINVAL and set @errp. |
| */ |
| static int bdrv_reset_options_allowed(BlockDriverState *bs, |
| const QDict *new_opts, Error **errp) |
| { |
| const QDictEntry *e; |
| /* These options are common to all block drivers and are handled |
| * in bdrv_reopen_prepare() so they can be left out of @new_opts */ |
| const char *const common_options[] = { |
| "node-name", "discard", "cache.direct", "cache.no-flush", |
| "read-only", "auto-read-only", "detect-zeroes", NULL |
| }; |
| |
| for (e = qdict_first(bs->options); e; e = qdict_next(bs->options, e)) { |
| if (!qdict_haskey(new_opts, e->key) && |
| !is_str_in_list(e->key, common_options) && |
| !is_str_in_list(e->key, bs->drv->mutable_opts)) { |
| error_setg(errp, "Option '%s' cannot be reset " |
| "to its default value", e->key); |
| return -EINVAL; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Returns true if @child can be reached recursively from @bs |
| */ |
| static bool bdrv_recurse_has_child(BlockDriverState *bs, |
| BlockDriverState *child) |
| { |
| BdrvChild *c; |
| |
| if (bs == child) { |
| return true; |
| } |
| |
| QLIST_FOREACH(c, &bs->children, next) { |
| if (bdrv_recurse_has_child(c->bs, child)) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /* |
| * Adds a BlockDriverState to a simple queue for an atomic, transactional |
| * reopen of multiple devices. |
| * |
| * bs_queue can either be an existing BlockReopenQueue that has had QTAILQ_INIT |
| * already performed, or alternatively may be NULL a new BlockReopenQueue will |
| * be created and initialized. This newly created BlockReopenQueue should be |
| * passed back in for subsequent calls that are intended to be of the same |
| * atomic 'set'. |
| * |
| * bs is the BlockDriverState to add to the reopen queue. |
| * |
| * options contains the changed options for the associated bs |
| * (the BlockReopenQueue takes ownership) |
| * |
| * flags contains the open flags for the associated bs |
| * |
| * returns a pointer to bs_queue, which is either the newly allocated |
| * bs_queue, or the existing bs_queue being used. |
| * |
| * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple(). |
| */ |
| static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, |
| BlockDriverState *bs, |
| QDict *options, |
| const BdrvChildClass *klass, |
| BdrvChildRole role, |
| bool parent_is_format, |
| QDict *parent_options, |
| int parent_flags, |
| bool keep_old_opts) |
| { |
| assert(bs != NULL); |
| |
| BlockReopenQueueEntry *bs_entry; |
| BdrvChild *child; |
| QDict *old_options, *explicit_options, *options_copy; |
| int flags; |
| QemuOpts *opts; |
| |
| /* Make sure that the caller remembered to use a drained section. This is |
| * important to avoid graph changes between the recursive queuing here and |
| * bdrv_reopen_multiple(). */ |
| assert(bs->quiesce_counter > 0); |
| |
| if (bs_queue == NULL) { |
| bs_queue = g_new0(BlockReopenQueue, 1); |
| QTAILQ_INIT(bs_queue); |
| } |
| |
| if (!options) { |
| options = qdict_new(); |
| } |
| |
| /* Check if this BlockDriverState is already in the queue */ |
| QTAILQ_FOREACH(bs_entry, bs_queue, entry) { |
| if (bs == bs_entry->state.bs) { |
| break; |
| } |
| } |
| |
| /* |
| * Precedence of options: |
| * 1. Explicitly passed in options (highest) |
| * 2. Retained from explicitly set options of bs |
| * 3. Inherited from parent node |
| * 4. Retained from effective options of bs |
| */ |
| |
| /* Old explicitly set values (don't overwrite by inherited value) */ |
| if (bs_entry || keep_old_opts) { |
| old_options = qdict_clone_shallow(bs_entry ? |
| bs_entry->state.explicit_options : |
| bs->explicit_options); |
| bdrv_join_options(bs, options, old_options); |
| qobject_unref(old_options); |
| } |
| |
| explicit_options = qdict_clone_shallow(options); |
| |
| /* Inherit from parent node */ |
| if (parent_options) { |
| flags = 0; |
| klass->inherit_options(role, parent_is_format, &flags, options, |
| parent_flags, parent_options); |
| } else { |
| flags = bdrv_get_flags(bs); |
| } |
| |
| if (keep_old_opts) { |
| /* Old values are used for options that aren't set yet */ |
| old_options = qdict_clone_shallow(bs->options); |
| bdrv_join_options(bs, options, old_options); |
| qobject_unref(old_options); |
| } |
| |
| /* We have the final set of options so let's update the flags */ |
| options_copy = qdict_clone_shallow(options); |
| opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); |
| qemu_opts_absorb_qdict(opts, options_copy, NULL); |
| update_flags_from_options(&flags, opts); |
| qemu_opts_del(opts); |
| qobject_unref(options_copy); |
| |
| /* bdrv_open_inherit() sets and clears some additional flags internally */ |
| flags &= ~BDRV_O_PROTOCOL; |
| if (flags & BDRV_O_RDWR) { |
| flags |= BDRV_O_ALLOW_RDWR; |
| } |
| |
| if (!bs_entry) { |
| bs_entry = g_new0(BlockReopenQueueEntry, 1); |
| QTAILQ_INSERT_TAIL(bs_queue, bs_entry, entry); |
| } else { |
| qobject_unref(bs_entry->state.options); |
| qobject_unref(bs_entry->state.explicit_options); |
| } |
| |
| bs_entry->state.bs = bs; |
| bs_entry->state.options = options; |
| bs_entry->state.explicit_options = explicit_options; |
| bs_entry->state.flags = flags; |
| |
| /* This needs to be overwritten in bdrv_reopen_prepare() */ |
| bs_entry->state.perm = UINT64_MAX; |
| bs_entry->state.shared_perm = 0; |
| |
| /* |
| * If keep_old_opts is false then it means that unspecified |
| * options must be reset to their original value. We don't allow |
| * resetting 'backing' but we need to know if the option is |
| * missing in order to decide if we have to return an error. |
| */ |
| if (!keep_old_opts) { |
| bs_entry->state.backing_missing = |
| !qdict_haskey(options, "backing") && |
| !qdict_haskey(options, "backing.driver"); |
| } |
| |
| QLIST_FOREACH(child, &bs->children, next) { |
| QDict *new_child_options = NULL; |
| bool child_keep_old = keep_old_opts; |
| |
| /* reopen can only change the options of block devices that were |
| * implicitly created and inherited options. For other (referenced) |
| * block devices, a syntax like "backing.foo" results in an error. */ |
| if (child->bs->inherits_from != bs) { |
| continue; |
| } |
| |
| /* Check if the options contain a child reference */ |
| if (qdict_haskey(options, child->name)) { |
| const char *childref = qdict_get_try_str(options, child->name); |
| /* |
| * The current child must not be reopened if the child |
| * reference is null or points to a different node. |
| */ |
| if (g_strcmp0(childref, child->bs->node_name)) { |
| continue; |
| } |
| /* |
| * If the child reference points to the current child then |
| * reopen it with its existing set of options (note that |
| * it can still inherit new options from the parent). |
| */ |
| child_keep_old = true; |
| } else { |
| /* Extract child options ("child-name.*") */ |
| char *child_key_dot = g_strdup_printf("%s.", child->name); |
| qdict_extract_subqdict(explicit_options, NULL, child_key_dot); |
| qdict_extract_subqdict(options, &new_child_options, child_key_dot); |
| g_free(child_key_dot); |
| } |
| |
| bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, |
| child->klass, child->role, bs->drv->is_format, |
| options, flags, child_keep_old); |
| } |
| |
| return bs_queue; |
| } |
| |
| BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, |
| BlockDriverState *bs, |
| QDict *options, bool keep_old_opts) |
| { |
| return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, 0, false, |
| NULL, 0, keep_old_opts); |
| } |
| |
| /* |
| * Reopen multiple BlockDriverStates atomically & transactionally. |
| * |
| * The queue passed in (bs_queue) must have been built up previous |
| * via bdrv_reopen_queue(). |
| * |
| * Reopens all BDS specified in the queue, with the appropriate |
| * flags. All devices are prepared for reopen, and failure of any |
| * device will cause all device changes to be abandoned, and intermediate |
| * data cleaned up. |
| * |
| * If all devices prepare successfully, then the changes are committed |
| * to all devices. |
| * |
| * All affected nodes must be drained between bdrv_reopen_queue() and |
| * bdrv_reopen_multiple(). |
| */ |
| int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) |
| { |
| int ret = -1; |
| BlockReopenQueueEntry *bs_entry, *next; |
| |
| assert(bs_queue != NULL); |
| |
| QTAILQ_FOREACH(bs_entry, bs_queue, entry) { |
| assert(bs_entry->state.bs->quiesce_counter > 0); |
| if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) { |
| goto cleanup; |
| } |
| bs_entry->prepared = true; |
| } |
| |
| QTAILQ_FOREACH(bs_entry, bs_queue, entry) { |
| BDRVReopenState *state = &bs_entry->state; |
| ret = bdrv_check_perm(state->bs, bs_queue, state->perm, |
| state->shared_perm, NULL, NULL, errp); |
| if (ret < 0) { |
| goto cleanup_perm; |
| } |
| /* Check if new_backing_bs would accept the new permissions */ |
| if (state->replace_backing_bs && state->new_backing_bs) { |
| uint64_t nperm, nshared; |
| bdrv_child_perm(state->bs, state->new_backing_bs, |
| NULL, bdrv_backing_role(state->bs), |
| bs_queue, state->perm, state->shared_perm, |
| &nperm, &nshared); |
| ret = bdrv_check_update_perm(state->new_backing_bs, NULL, |
| nperm, nshared, NULL, NULL, errp); |
| if (ret < 0) { |
| goto cleanup_perm; |
| } |
| } |
| bs_entry->perms_checked = true; |
| } |
| |
| /* |
| * If we reach this point, we have success and just need to apply the |
| * changes. |
| * |
| * Reverse order is used to comfort qcow2 driver: on commit it need to write |
| * IN_USE flag to the image, to mark bitmaps in the image as invalid. But |
| * children are usually goes after parents in reopen-queue, so go from last |
| * to first element. |
| */ |
| QTAILQ_FOREACH_REVERSE(bs_entry, bs_queue, entry) { |
| bdrv_reopen_commit(&bs_entry->state); |
| } |
| |
| ret = 0; |
| cleanup_perm: |
| QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { |
| BDRVReopenState *state = &bs_entry->state; |
| |
| if (!bs_entry->perms_checked) { |
| continue; |
| } |
| |
| if (ret == 0) { |
| bdrv_set_perm(state->bs, state->perm, state->shared_perm); |
| } else { |
| bdrv_abort_perm_update(state->bs); |
| if (state->replace_backing_bs && state->new_backing_bs) { |
| bdrv_abort_perm_update(state->new_backing_bs); |
| } |
| } |
| } |
| |
| if (ret == 0) { |
| QTAILQ_FOREACH_REVERSE(bs_entry, bs_queue, entry) { |
| BlockDriverState *bs = bs_entry->state.bs; |
| |
| if (bs->drv->bdrv_reopen_commit_post) |
| bs->drv->bdrv_reopen_commit_post(&bs_entry->state); |
| } |
| } |
| cleanup: |
| QTAILQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { |
| if (ret) { |
| if (bs_entry->prepared) { |
| bdrv_reopen_abort(&bs_entry->state); |
| } |
| qobject_unref(bs_entry->state.explicit_options); |
| qobject_unref(bs_entry->state.options); |
| } |
| if (bs_entry->state.new_backing_bs) { |
| bdrv_unref(bs_entry->state.new_backing_bs); |
| } |
| g_free(bs_entry); |
| } |
| g_free(bs_queue); |
| |
| return ret; |
| } |
| |
| int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only, |
| Error **errp) |
| { |
| int ret; |
| BlockReopenQueue *queue; |
| QDict *opts = qdict_new(); |
| |
| qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only); |
| |
| bdrv_subtree_drained_begin(bs); |
| queue = bdrv_reopen_queue(NULL, bs, opts, true); |
| ret = bdrv_reopen_multiple(queue, errp); |
| bdrv_subtree_drained_end(bs); |
| |
| return ret; |
| } |
| |
| static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q, |
| BdrvChild *c) |
| { |
| BlockReopenQueueEntry *entry; |
| |
| QTAILQ_FOREACH(entry, q, entry) { |
| BlockDriverState *bs = entry->state.bs; |
| BdrvChild *child; |
| |
| QLIST_FOREACH(child, &bs->children, next) { |
| if (child == c) { |
| return entry; |
| } |
| } |
| } |
| |
| return NULL; |
| } |
| |
| static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs, |
| uint64_t *perm, uint64_t *shared) |
| { |
| BdrvChild *c; |
| BlockReopenQueueEntry *parent; |
| uint64_t cumulative_perms = 0; |
| uint64_t cumulative_shared_perms = BLK_PERM_ALL; |
| |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| parent = find_parent_in_reopen_queue(q, c); |
| if (!parent) { |
| cumulative_perms |= c->perm; |
| cumulative_shared_perms &= c->shared_perm; |
| } else { |
| uint64_t nperm, nshared; |
| |
| bdrv_child_perm(parent->state.bs, bs, c, c->role, q, |
| parent->state.perm, parent->state.shared_perm, |
| &nperm, &nshared); |
| |
| cumulative_perms |= nperm; |
| cumulative_shared_perms &= nshared; |
| } |
| } |
| *perm = cumulative_perms; |
| *shared = cumulative_shared_perms; |
| } |
| |
| static bool bdrv_reopen_can_attach(BlockDriverState *parent, |
| BdrvChild *child, |
| BlockDriverState *new_child, |
| Error **errp) |
| { |
| AioContext *parent_ctx = bdrv_get_aio_context(parent); |
| AioContext *child_ctx = bdrv_get_aio_context(new_child); |
| GSList *ignore; |
| bool ret; |
| |
| ignore = g_slist_prepend(NULL, child); |
| ret = bdrv_can_set_aio_context(new_child, parent_ctx, &ignore, NULL); |
| g_slist_free(ignore); |
| if (ret) { |
| return ret; |
| } |
| |
| ignore = g_slist_prepend(NULL, child); |
| ret = bdrv_can_set_aio_context(parent, child_ctx, &ignore, errp); |
| g_slist_free(ignore); |
| return ret; |
| } |
| |
| /* |
| * Take a BDRVReopenState and check if the value of 'backing' in the |
| * reopen_state->options QDict is valid or not. |
| * |
| * If 'backing' is missing from the QDict then return 0. |
| * |
| * If 'backing' contains the node name of the backing file of |
| * reopen_state->bs then return 0. |
| * |
| * If 'backing' contains a different node name (or is null) then check |
| * whether the current backing file can be replaced with the new one. |
| * If that's the case then reopen_state->replace_backing_bs is set to |
| * true and reopen_state->new_backing_bs contains a pointer to the new |
| * backing BlockDriverState (or NULL). |
| * |
| * Return 0 on success, otherwise return < 0 and set @errp. |
| */ |
| static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, |
| Error **errp) |
| { |
| BlockDriverState *bs = reopen_state->bs; |
| BlockDriverState *overlay_bs, *new_backing_bs; |
| QObject *value; |
| const char *str; |
| |
| value = qdict_get(reopen_state->options, "backing"); |
| if (value == NULL) { |
| return 0; |
| } |
| |
| switch (qobject_type(value)) { |
| case QTYPE_QNULL: |
| new_backing_bs = NULL; |
| break; |
| case QTYPE_QSTRING: |
| str = qobject_get_try_str(value); |
| new_backing_bs = bdrv_lookup_bs(NULL, str, errp); |
| if (new_backing_bs == NULL) { |
| return -EINVAL; |
| } else if (bdrv_recurse_has_child(new_backing_bs, bs)) { |
| error_setg(errp, "Making '%s' a backing file of '%s' " |
| "would create a cycle", str, bs->node_name); |
| return -EINVAL; |
| } |
| break; |
| default: |
| /* 'backing' does not allow any other data type */ |
| g_assert_not_reached(); |
| } |
| |
| /* |
| * Check AioContext compatibility so that the bdrv_set_backing_hd() call in |
| * bdrv_reopen_commit() won't fail. |
| */ |
| if (new_backing_bs) { |
| if (!bdrv_reopen_can_attach(bs, bs->backing, new_backing_bs, errp)) { |
| return -EINVAL; |
| } |
| } |
| |
| /* |
| * Find the "actual" backing file by skipping all links that point |
| * to an implicit node, if any (e.g. a commit filter node). |
| */ |
| overlay_bs = bs; |
| while (backing_bs(overlay_bs) && backing_bs(overlay_bs)->implicit) { |
| overlay_bs = backing_bs(overlay_bs); |
| } |
| |
| /* If we want to replace the backing file we need some extra checks */ |
| if (new_backing_bs != backing_bs(overlay_bs)) { |
| /* Check for implicit nodes between bs and its backing file */ |
| if (bs != overlay_bs) { |
| error_setg(errp, "Cannot change backing link if '%s' has " |
| "an implicit backing file", bs->node_name); |
| return -EPERM; |
| } |
| /* Check if the backing link that we want to replace is frozen */ |
| if (bdrv_is_backing_chain_frozen(overlay_bs, backing_bs(overlay_bs), |
| errp)) { |
| return -EPERM; |
| } |
| reopen_state->replace_backing_bs = true; |
| if (new_backing_bs) { |
| bdrv_ref(new_backing_bs); |
| reopen_state->new_backing_bs = new_backing_bs; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Prepares a BlockDriverState for reopen. All changes are staged in the |
| * 'opaque' field of the BDRVReopenState, which is used and allocated by |
| * the block driver layer .bdrv_reopen_prepare() |
| * |
| * bs is the BlockDriverState to reopen |
| * flags are the new open flags |
| * queue is the reopen queue |
| * |
| * Returns 0 on success, non-zero on error. On error errp will be set |
| * as well. |
| * |
| * On failure, bdrv_reopen_abort() will be called to clean up any data. |
| * It is the responsibility of the caller to then call the abort() or |
| * commit() for any other BDS that have been left in a prepare() state |
| * |
| */ |
| int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, |
| Error **errp) |
| { |
| int ret = -1; |
| int old_flags; |
| Error *local_err = NULL; |
| BlockDriver *drv; |
| QemuOpts *opts; |
| QDict *orig_reopen_opts; |
| char *discard = NULL; |
| bool read_only; |
| bool drv_prepared = false; |
| |
| assert(reopen_state != NULL); |
| assert(reopen_state->bs->drv != NULL); |
| drv = reopen_state->bs->drv; |
| |
| /* This function and each driver's bdrv_reopen_prepare() remove |
| * entries from reopen_state->options as they are processed, so |
| * we need to make a copy of the original QDict. */ |
| orig_reopen_opts = qdict_clone_shallow(reopen_state->options); |
| |
| /* Process generic block layer options */ |
| opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); |
| if (!qemu_opts_absorb_qdict(opts, reopen_state->options, errp)) { |
| ret = -EINVAL; |
| goto error; |
| } |
| |
| /* This was already called in bdrv_reopen_queue_child() so the flags |
| * are up-to-date. This time we simply want to remove the options from |
| * QemuOpts in order to indicate that they have been processed. */ |
| old_flags = reopen_state->flags; |
| update_flags_from_options(&reopen_state->flags, opts); |
| assert(old_flags == reopen_state->flags); |
| |
| discard = qemu_opt_get_del(opts, BDRV_OPT_DISCARD); |
| if (discard != NULL) { |
| if (bdrv_parse_discard_flags(discard, &reopen_state->flags) != 0) { |
| error_setg(errp, "Invalid discard option"); |
| ret = -EINVAL; |
| goto error; |
| } |
| } |
| |
| reopen_state->detect_zeroes = |
| bdrv_parse_detect_zeroes(opts, reopen_state->flags, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| ret = -EINVAL; |
| goto error; |
| } |
| |
| /* All other options (including node-name and driver) must be unchanged. |
| * Put them back into the QDict, so that they are checked at the end |
| * of this function. */ |
| qemu_opts_to_qdict(opts, reopen_state->options); |
| |
| /* If we are to stay read-only, do not allow permission change |
| * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is |
| * not set, or if the BDS still has copy_on_read enabled */ |
| read_only = !(reopen_state->flags & BDRV_O_RDWR); |
| ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto error; |
| } |
| |
| /* Calculate required permissions after reopening */ |
| bdrv_reopen_perm(queue, reopen_state->bs, |
| &reopen_state->perm, &reopen_state->shared_perm); |
| |
| ret = bdrv_flush(reopen_state->bs); |
| if (ret) { |
| error_setg_errno(errp, -ret, "Error flushing drive"); |
| goto error; |
| } |
| |
| if (drv->bdrv_reopen_prepare) { |
| /* |
| * If a driver-specific option is missing, it means that we |
| * should reset it to its default value. |
| * But not all options allow that, so we need to check it first. |
| */ |
| ret = bdrv_reset_options_allowed(reopen_state->bs, |
| reopen_state->options, errp); |
| if (ret) { |
| goto error; |
| } |
| |
| ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); |
| if (ret) { |
| if (local_err != NULL) { |
| error_propagate(errp, local_err); |
| } else { |
| bdrv_refresh_filename(reopen_state->bs); |
| error_setg(errp, "failed while preparing to reopen image '%s'", |
| reopen_state->bs->filename); |
| } |
| goto error; |
| } |
| } else { |
| /* It is currently mandatory to have a bdrv_reopen_prepare() |
| * handler for each supported drv. */ |
| error_setg(errp, "Block format '%s' used by node '%s' " |
| "does not support reopening files", drv->format_name, |
| bdrv_get_device_or_node_name(reopen_state->bs)); |
| ret = -1; |
| goto error; |
| } |
| |
| drv_prepared = true; |
| |
| /* |
| * We must provide the 'backing' option if the BDS has a backing |
| * file or if the image file has a backing file name as part of |
| * its metadata. Otherwise the 'backing' option can be omitted. |
| */ |
| if (drv->supports_backing && reopen_state->backing_missing && |
| (backing_bs(reopen_state->bs) || reopen_state->bs->backing_file[0])) { |
| error_setg(errp, "backing is missing for '%s'", |
| reopen_state->bs->node_name); |
| ret = -EINVAL; |
| goto error; |
| } |
| |
| /* |
| * Allow changing the 'backing' option. The new value can be |
| * either a reference to an existing node (using its node name) |
| * or NULL to simply detach the current backing file. |
| */ |
| ret = bdrv_reopen_parse_backing(reopen_state, errp); |
| if (ret < 0) { |
| goto error; |
| } |
| qdict_del(reopen_state->options, "backing"); |
| |
| /* Options that are not handled are only okay if they are unchanged |
| * compared to the old state. It is expected that some options are only |
| * used for the initial open, but not reopen (e.g. filename) */ |
| if (qdict_size(reopen_state->options)) { |
| const QDictEntry *entry = qdict_first(reopen_state->options); |
| |
| do { |
| QObject *new = entry->value; |
| QObject *old = qdict_get(reopen_state->bs->options, entry->key); |
| |
| /* Allow child references (child_name=node_name) as long as they |
| * point to the current child (i.e. everything stays the same). */ |
| if (qobject_type(new) == QTYPE_QSTRING) { |
| BdrvChild *child; |
| QLIST_FOREACH(child, &reopen_state->bs->children, next) { |
| if (!strcmp(child->name, entry->key)) { |
| break; |
| } |
| } |
| |
| if (child) { |
| const char *str = qobject_get_try_str(new); |
| if (!strcmp(child->bs->node_name, str)) { |
| continue; /* Found child with this name, skip option */ |
| } |
| } |
| } |
| |
| /* |
| * TODO: When using -drive to specify blockdev options, all values |
| * will be strings; however, when using -blockdev, blockdev-add or |
| * filenames using the json:{} pseudo-protocol, they will be |
| * correctly typed. |
| * In contrast, reopening options are (currently) always strings |
| * (because you can only specify them through qemu-io; all other |
| * callers do not specify any options). |
| * Therefore, when using anything other than -drive to create a BDS, |
| * this cannot detect non-string options as unchanged, because |
| * qobject_is_equal() always returns false for objects of different |
| * type. In the future, this should be remedied by correctly typing |
| * all options. For now, this is not too big of an issue because |
| * the user can simply omit options which cannot be changed anyway, |
| * so they will stay unchanged. |
| */ |
| if (!qobject_is_equal(new, old)) { |
| error_setg(errp, "Cannot change the option '%s'", entry->key); |
| ret = -EINVAL; |
| goto error; |
| } |
| } while ((entry = qdict_next(reopen_state->options, entry))); |
| } |
| |
| ret = 0; |
| |
| /* Restore the original reopen_state->options QDict */ |
| qobject_unref(reopen_state->options); |
| reopen_state->options = qobject_ref(orig_reopen_opts); |
| |
| error: |
| if (ret < 0 && drv_prepared) { |
| /* drv->bdrv_reopen_prepare() has succeeded, so we need to |
| * call drv->bdrv_reopen_abort() before signaling an error |
| * (bdrv_reopen_multiple() will not call bdrv_reopen_abort() |
| * when the respective bdrv_reopen_prepare() has failed) */ |
| if (drv->bdrv_reopen_abort) { |
| drv->bdrv_reopen_abort(reopen_state); |
| } |
| } |
| qemu_opts_del(opts); |
| qobject_unref(orig_reopen_opts); |
| g_free(discard); |
| return ret; |
| } |
| |
| /* |
| * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and |
| * makes them final by swapping the staging BlockDriverState contents into |
| * the active BlockDriverState contents. |
| */ |
| void bdrv_reopen_commit(BDRVReopenState *reopen_state) |
| { |
| BlockDriver *drv; |
| BlockDriverState *bs; |
| BdrvChild *child; |
| |
| assert(reopen_state != NULL); |
| bs = reopen_state->bs; |
| drv = bs->drv; |
| assert(drv != NULL); |
| |
| /* If there are any driver level actions to take */ |
| if (drv->bdrv_reopen_commit) { |
| drv->bdrv_reopen_commit(reopen_state); |
| } |
| |
| /* set BDS specific flags now */ |
| qobject_unref(bs->explicit_options); |
| qobject_unref(bs->options); |
| |
| bs->explicit_options = reopen_state->explicit_options; |
| bs->options = reopen_state->options; |
| bs->open_flags = reopen_state->flags; |
| bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); |
| bs->detect_zeroes = reopen_state->detect_zeroes; |
| |
| if (reopen_state->replace_backing_bs) { |
| qdict_del(bs->explicit_options, "backing"); |
| qdict_del(bs->options, "backing"); |
| } |
| |
| /* Remove child references from bs->options and bs->explicit_options. |
| * Child options were already removed in bdrv_reopen_queue_child() */ |
| QLIST_FOREACH(child, &bs->children, next) { |
| qdict_del(bs->explicit_options, child->name); |
| qdict_del(bs->options, child->name); |
| } |
| |
| /* |
| * Change the backing file if a new one was specified. We do this |
| * after updating bs->options, so bdrv_refresh_filename() (called |
| * from bdrv_set_backing_hd()) has the new values. |
| */ |
| if (reopen_state->replace_backing_bs) { |
| BlockDriverState *old_backing_bs = backing_bs(bs); |
| assert(!old_backing_bs || !old_backing_bs->implicit); |
| /* Abort the permission update on the backing bs we're detaching */ |
| if (old_backing_bs) { |
| bdrv_abort_perm_update(old_backing_bs); |
| } |
| bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort); |
| } |
| |
| bdrv_refresh_limits(bs, NULL); |
| } |
| |
| /* |
| * Abort the reopen, and delete and free the staged changes in |
| * reopen_state |
| */ |
| void bdrv_reopen_abort(BDRVReopenState *reopen_state) |
| { |
| BlockDriver *drv; |
| |
| assert(reopen_state != NULL); |
| drv = reopen_state->bs->drv; |
| assert(drv != NULL); |
| |
| if (drv->bdrv_reopen_abort) { |
| drv->bdrv_reopen_abort(reopen_state); |
| } |
| } |
| |
| |
| static void bdrv_close(BlockDriverState *bs) |
| { |
| BdrvAioNotifier *ban, *ban_next; |
| BdrvChild *child, *next; |
| |
| assert(!bs->refcnt); |
| |
| bdrv_drained_begin(bs); /* complete I/O */ |
| bdrv_flush(bs); |
| bdrv_drain(bs); /* in case flush left pending I/O */ |
| |
| if (bs->drv) { |
| if (bs->drv->bdrv_close) { |
| bs->drv->bdrv_close(bs); |
| } |
| bs->drv = NULL; |
| } |
| |
| QLIST_FOREACH_SAFE(child, &bs->children, next, next) { |
| bdrv_unref_child(bs, child); |
| } |
| |
| bs->backing = NULL; |
| bs->file = NULL; |
| g_free(bs->opaque); |
| bs->opaque = NULL; |
| atomic_set(&bs->copy_on_read, 0); |
| bs->backing_file[0] = '\0'; |
| bs->backing_format[0] = '\0'; |
| bs->total_sectors = 0; |
| bs->encrypted = false; |
| bs->sg = false; |
| qobject_unref(bs->options); |
| qobject_unref(bs->explicit_options); |
| bs->options = NULL; |
| bs->explicit_options = NULL; |
| qobject_unref(bs->full_open_options); |
| bs->full_open_options = NULL; |
| |
| bdrv_release_named_dirty_bitmaps(bs); |
| assert(QLIST_EMPTY(&bs->dirty_bitmaps)); |
| |
| QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { |
| g_free(ban); |
| } |
| QLIST_INIT(&bs->aio_notifiers); |
| bdrv_drained_end(bs); |
| } |
| |
| void bdrv_close_all(void) |
| { |
| assert(job_next(NULL) == NULL); |
| nbd_export_close_all(); |
| |
| /* Drop references from requests still in flight, such as canceled block |
| * jobs whose AIO context has not been polled yet */ |
| bdrv_drain_all(); |
| |
| blk_remove_all_bs(); |
| blockdev_close_all_bdrv_states(); |
| |
| assert(QTAILQ_EMPTY(&all_bdrv_states)); |
| } |
| |
| static bool should_update_child(BdrvChild *c, BlockDriverState *to) |
| { |
| GQueue *queue; |
| GHashTable *found; |
| bool ret; |
| |
| if (c->klass->stay_at_node) { |
| return false; |
| } |
| |
| /* If the child @c belongs to the BDS @to, replacing the current |
| * c->bs by @to would mean to create a loop. |
| * |
| * Such a case occurs when appending a BDS to a backing chain. |
| * For instance, imagine the following chain: |
| * |
| * guest device -> node A -> further backing chain... |
| * |
| * Now we create a new BDS B which we want to put on top of this |
| * chain, so we first attach A as its backing node: |
| * |
| * node B |
| * | |
| * v |
| * guest device -> node A -> further backing chain... |
| * |
| * Finally we want to replace A by B. When doing that, we want to |
| * replace all pointers to A by pointers to B -- except for the |
| * pointer from B because (1) that would create a loop, and (2) |
| * that pointer should simply stay intact: |
| * |
| * guest device -> node B |
| * | |
| * v |
| * node A -> further backing chain... |
| * |
| * In general, when replacing a node A (c->bs) by a node B (@to), |
| * if A is a child of B, that means we cannot replace A by B there |
| * because that would create a loop. Silently detaching A from B |
| * is also not really an option. So overall just leaving A in |
| * place there is the most sensible choice. |
| * |
| * We would also create a loop in any cases where @c is only |
| * indirectly referenced by @to. Prevent this by returning false |
| * if @c is found (by breadth-first search) anywhere in the whole |
| * subtree of @to. |
| */ |
| |
| ret = true; |
| found = g_hash_table_new(NULL, NULL); |
| g_hash_table_add(found, to); |
| queue = g_queue_new(); |
| g_queue_push_tail(queue, to); |
| |
| while (!g_queue_is_empty(queue)) { |
| BlockDriverState *v = g_queue_pop_head(queue); |
| BdrvChild *c2; |
| |
| QLIST_FOREACH(c2, &v->children, next) { |
| if (c2 == c) { |
| ret = false; |
| break; |
| } |
| |
| if (g_hash_table_contains(found, c2->bs)) { |
| continue; |
| } |
| |
| g_queue_push_tail(queue, c2->bs); |
| g_hash_table_add(found, c2->bs); |
| } |
| } |
| |
| g_queue_free(queue); |
| g_hash_table_destroy(found); |
| |
| return ret; |
| } |
| |
| void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, |
| Error **errp) |
| { |
| BdrvChild *c, *next; |
| GSList *list = NULL, *p; |
| uint64_t perm = 0, shared = BLK_PERM_ALL; |
| int ret; |
| |
| /* Make sure that @from doesn't go away until we have successfully attached |
| * all of its parents to @to. */ |
| bdrv_ref(from); |
| |
| assert(qemu_get_current_aio_context() == qemu_get_aio_context()); |
| assert(bdrv_get_aio_context(from) == bdrv_get_aio_context(to)); |
| bdrv_drained_begin(from); |
| |
| /* Put all parents into @list and calculate their cumulative permissions */ |
| QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { |
| assert(c->bs == from); |
| if (!should_update_child(c, to)) { |
| continue; |
| } |
| if (c->frozen) { |
| error_setg(errp, "Cannot change '%s' link to '%s'", |
| c->name, from->node_name); |
| goto out; |
| } |
| list = g_slist_prepend(list, c); |
| perm |= c->perm; |
| shared &= c->shared_perm; |
| } |
| |
| /* Check whether the required permissions can be granted on @to, ignoring |
| * all BdrvChild in @list so that they can't block themselves. */ |
| ret = bdrv_check_update_perm(to, NULL, perm, shared, list, NULL, errp); |
| if (ret < 0) { |
| bdrv_abort_perm_update(to); |
| goto out; |
| } |
| |
| /* Now actually perform the change. We performed the permission check for |
| * all elements of @list at once, so set the permissions all at once at the |
| * very end. */ |
| for (p = list; p != NULL; p = p->next) { |
| c = p->data; |
| |
| bdrv_ref(to); |
| bdrv_replace_child_noperm(c, to); |
| bdrv_unref(from); |
| } |
| |
| bdrv_get_cumulative_perm(to, &perm, &shared); |
| bdrv_set_perm(to, perm, shared); |
| |
| out: |
| g_slist_free(list); |
| bdrv_drained_end(from); |
| bdrv_unref(from); |
| } |
| |
| /* |
| * Add new bs contents at the top of an image chain while the chain is |
| * live, while keeping required fields on the top layer. |
| * |
| * This will modify the BlockDriverState fields, and swap contents |
| * between bs_new and bs_top. Both bs_new and bs_top are modified. |
| * |
| * bs_new must not be attached to a BlockBackend. |
| * |
| * This function does not create any image files. |
| * |
| * bdrv_append() takes ownership of a bs_new reference and unrefs it because |
| * that's what the callers commonly need. bs_new will be referenced by the old |
| * parents of bs_top after bdrv_append() returns. If the caller needs to keep a |
| * reference of its own, it must call bdrv_ref(). |
| */ |
| void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, |
| Error **errp) |
| { |
| Error *local_err = NULL; |
| |
| bdrv_set_backing_hd(bs_new, bs_top, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto out; |
| } |
| |
| bdrv_replace_node(bs_top, bs_new, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| bdrv_set_backing_hd(bs_new, NULL, &error_abort); |
| goto out; |
| } |
| |
| /* bs_new is now referenced by its new parents, we don't need the |
| * additional reference any more. */ |
| out: |
| bdrv_unref(bs_new); |
| } |
| |
| static void bdrv_delete(BlockDriverState *bs) |
| { |
| assert(bdrv_op_blocker_is_empty(bs)); |
| assert(!bs->refcnt); |
| |
| /* remove from list, if necessary */ |
| if (bs->node_name[0] != '\0') { |
| QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); |
| } |
| QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list); |
| |
| bdrv_close(bs); |
| |
| g_free(bs); |
| } |
| |
| /* |
| * Run consistency checks on an image |
| * |
| * Returns 0 if the check could be completed (it doesn't mean that the image is |
| * free of errors) or -errno when an internal error occurred. The results of the |
| * check are stored in res. |
| */ |
| static int coroutine_fn bdrv_co_check(BlockDriverState *bs, |
| BdrvCheckResult *res, BdrvCheckMode fix) |
| { |
| if (bs->drv == NULL) { |
| return -ENOMEDIUM; |
| } |
| if (bs->drv->bdrv_co_check == NULL) { |
| return -ENOTSUP; |
| } |
| |
| memset(res, 0, sizeof(*res)); |
| return bs->drv->bdrv_co_check(bs, res, fix); |
| } |
| |
| typedef struct CheckCo { |
| BlockDriverState *bs; |
| BdrvCheckResult *res; |
| BdrvCheckMode fix; |
| int ret; |
| } CheckCo; |
| |
| static void coroutine_fn bdrv_check_co_entry(void *opaque) |
| { |
| CheckCo *cco = opaque; |
| cco->ret = bdrv_co_check(cco->bs, cco->res, cco->fix); |
| aio_wait_kick(); |
| } |
| |
| int bdrv_check(BlockDriverState *bs, |
| BdrvCheckResult *res, BdrvCheckMode fix) |
| { |
| Coroutine *co; |
| CheckCo cco = { |
| .bs = bs, |
| .res = res, |
| .ret = -EINPROGRESS, |
| .fix = fix, |
| }; |
| |
| if (qemu_in_coroutine()) { |
| /* Fast-path if already in coroutine context */ |
| bdrv_check_co_entry(&cco); |
| } else { |
| co = qemu_coroutine_create(bdrv_check_co_entry, &cco); |
| bdrv_coroutine_enter(bs, co); |
| BDRV_POLL_WHILE(bs, cco.ret == -EINPROGRESS); |
| } |
| |
| return cco.ret; |
| } |
| |
| /* |
| * Return values: |
| * 0 - success |
| * -EINVAL - backing format specified, but no file |
| * -ENOSPC - can't update the backing file because no space is left in the |
| * image file header |
| * -ENOTSUP - format driver doesn't support changing the backing file |
| */ |
| int bdrv_change_backing_file(BlockDriverState *bs, |
| const char *backing_file, const char *backing_fmt) |
| { |
| BlockDriver *drv = bs->drv; |
| int ret; |
| |
| if (!drv) { |
| return -ENOMEDIUM; |
| } |
| |
| /* Backing file format doesn't make sense without a backing file */ |
| if (backing_fmt && !backing_file) { |
| return -EINVAL; |
| } |
| |
| if (drv->bdrv_change_backing_file != NULL) { |
| ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); |
| } else { |
| ret = -ENOTSUP; |
| } |
| |
| if (ret == 0) { |
| pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); |
| pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); |
| pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file), |
| backing_file ?: ""); |
| } |
| return ret; |
| } |
| |
| /* |
| * Finds the image layer in the chain that has 'bs' as its backing file. |
| * |
| * active is the current topmost image. |
| * |
| * Returns NULL if bs is not found in active's image chain, |
| * or if active == bs. |
| * |
| * Returns the bottommost base image if bs == NULL. |
| */ |
| BlockDriverState *bdrv_find_overlay(BlockDriverState *active, |
| BlockDriverState *bs) |
| { |
| while (active && bs != backing_bs(active)) { |
| active = backing_bs(active); |
| } |
| |
| return active; |
| } |
| |
| /* Given a BDS, searches for the base layer. */ |
| BlockDriverState *bdrv_find_base(BlockDriverState *bs) |
| { |
| return bdrv_find_overlay(bs, NULL); |
| } |
| |
| /* |
| * Return true if at least one of the backing links between @bs and |
| * @base is frozen. @errp is set if that's the case. |
| * @base must be reachable from @bs, or NULL. |
| */ |
| bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base, |
| Error **errp) |
| { |
| BlockDriverState *i; |
| |
| for (i = bs; i != base; i = backing_bs(i)) { |
| if (i->backing && i->backing->frozen) { |
| error_setg(errp, "Cannot change '%s' link from '%s' to '%s'", |
| i->backing->name, i->node_name, |
| backing_bs(i)->node_name); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /* |
| * Freeze all backing links between @bs and @base. |
| * If any of the links is already frozen the operation is aborted and |
| * none of the links are modified. |
| * @base must be reachable from @bs, or NULL. |
| * Returns 0 on success. On failure returns < 0 and sets @errp. |
| */ |
| int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base, |
| Error **errp) |
| { |
| BlockDriverState *i; |
| |
| if (bdrv_is_backing_chain_frozen(bs, base, errp)) { |
| return -EPERM; |
| } |
| |
| for (i = bs; i != base; i = backing_bs(i)) { |
| if (i->backing && backing_bs(i)->never_freeze) { |
| error_setg(errp, "Cannot freeze '%s' link to '%s'", |
| i->backing->name, backing_bs(i)->node_name); |
| return -EPERM; |
| } |
| } |
| |
| for (i = bs; i != base; i = backing_bs(i)) { |
| if (i->backing) { |
| i->backing->frozen = true; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Unfreeze all backing links between @bs and @base. The caller must |
| * ensure that all links are frozen before using this function. |
| * @base must be reachable from @bs, or NULL. |
| */ |
| void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base) |
| { |
| BlockDriverState *i; |
| |
| for (i = bs; i != base; i = backing_bs(i)) { |
| if (i->backing) { |
| assert(i->backing->frozen); |
| i->backing->frozen = false; |
| } |
| } |
| } |
| |
| /* |
| * Drops images above 'base' up to and including 'top', and sets the image |
| * above 'top' to have base as its backing file. |
| * |
| * Requires that the overlay to 'top' is opened r/w, so that the backing file |
| * information in 'bs' can be properly updated. |
| * |
| * E.g., this will convert the following chain: |
| * bottom <- base <- intermediate <- top <- active |
| * |
| * to |
| * |
| * bottom <- base <- active |
| * |
| * It is allowed for bottom==base, in which case it converts: |
| * |
| * base <- intermediate <- top <- active |
| * |
| * to |
| * |
| * base <- active |
| * |
| * If backing_file_str is non-NULL, it will be used when modifying top's |
| * overlay image metadata. |
| * |
| * Error conditions: |
| * if active == top, that is considered an error |
| * |
| */ |
| int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, |
| const char *backing_file_str) |
| { |
| BlockDriverState *explicit_top = top; |
| bool update_inherits_from; |
| BdrvChild *c, *next; |
| Error *local_err = NULL; |
| int ret = -EIO; |
| |
| bdrv_ref(top); |
| bdrv_subtree_drained_begin(top); |
| |
| if (!top->drv || !base->drv) { |
| goto exit; |
| } |
| |
| /* Make sure that base is in the backing chain of top */ |
| if (!bdrv_chain_contains(top, base)) { |
| goto exit; |
| } |
| |
| /* This function changes all links that point to top and makes |
| * them point to base. Check that none of them is frozen. */ |
| QLIST_FOREACH(c, &top->parents, next_parent) { |
| if (c->frozen) { |
| goto exit; |
| } |
| } |
| |
| /* If 'base' recursively inherits from 'top' then we should set |
| * base->inherits_from to top->inherits_from after 'top' and all |
| * other intermediate nodes have been dropped. |
| * If 'top' is an implicit node (e.g. "commit_top") we should skip |
| * it because no one inherits from it. We use explicit_top for that. */ |
| while (explicit_top && explicit_top->implicit) { |
| explicit_top = backing_bs(explicit_top); |
| } |
| update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top); |
| |
| /* success - we can delete the intermediate states, and link top->base */ |
| /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once |
| * we've figured out how they should work. */ |
| if (!backing_file_str) { |
| bdrv_refresh_filename(base); |
| backing_file_str = base->filename; |
| } |
| |
| QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) { |
| /* Check whether we are allowed to switch c from top to base */ |
| GSList *ignore_children = g_slist_prepend(NULL, c); |
| ret = bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm, |
| ignore_children, NULL, &local_err); |
| g_slist_free(ignore_children); |
| if (ret < 0) { |
| error_report_err(local_err); |
| goto exit; |
| } |
| |
| /* If so, update the backing file path in the image file */ |
| if (c->klass->update_filename) { |
| ret = c->klass->update_filename(c, base, backing_file_str, |
| &local_err); |
| if (ret < 0) { |
| bdrv_abort_perm_update(base); |
| error_report_err(local_err); |
| goto exit; |
| } |
| } |
| |
| /* Do the actual switch in the in-memory graph. |
| * Completes bdrv_check_update_perm() transaction internally. */ |
| bdrv_ref(base); |
| bdrv_replace_child(c, base); |
| bdrv_unref(top); |
| } |
| |
| if (update_inherits_from) { |
| base->inherits_from = explicit_top->inherits_from; |
| } |
| |
| ret = 0; |
| exit: |
| bdrv_subtree_drained_end(top); |
| bdrv_unref(top); |
| return ret; |
| } |
| |
| /** |
| * Length of a allocated file in bytes. Sparse files are counted by actual |
| * allocated space. Return < 0 if error or unknown. |
| */ |
| int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) |
| { |
| BlockDriver *drv = bs->drv; |
| if (!drv) { |
| return -ENOMEDIUM; |
| } |
| if (drv->bdrv_get_allocated_file_size) { |
| return drv->bdrv_get_allocated_file_size(bs); |
| } |
| if (bs->file) { |
| return bdrv_get_allocated_file_size(bs->file->bs); |
| } |
| return -ENOTSUP; |
| } |
| |
| /* |
| * bdrv_measure: |
| * @drv: Format driver |
| * @opts: Creation options for new image |
| * @in_bs: Existing image containing data for new image (may be NULL) |
| * @errp: Error object |
| * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo()) |
| * or NULL on error |
| * |
| * Calculate file size required to create a new image. |
| * |
| * If @in_bs is given then space for allocated clusters and zero clusters |
| * from that image are included in the calculation. If @opts contains a |
| * backing file that is shared by @in_bs then backing clusters may be omitted |
| * from the calculation. |
| * |
| * If @in_bs is NULL then the calculation includes no allocated clusters |
| * unless a preallocation option is given in @opts. |
| * |
| * Note that @in_bs may use a different BlockDriver from @drv. |
| * |
| * If an error occurs the @errp pointer is set. |
| */ |
| BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts, |
| BlockDriverState *in_bs, Error **errp) |
| { |
| if (!drv->bdrv_measure) { |
| error_setg(errp, "Block driver '%s' does not support size measurement", |
| drv->format_name); |
| return NULL; |
| } |
| |
| return drv->bdrv_measure(opts, in_bs, errp); |
| } |
| |
| /** |
| * Return number of sectors on success, -errno on error. |
| */ |
| int64_t bdrv_nb_sectors(BlockDriverState *bs) |
| { |
| BlockDriver *drv = bs->drv; |
| |
| if (!drv) |
| return -ENOMEDIUM; |
| |
| if (drv->has_variable_length) { |
| int ret = refresh_total_sectors(bs, bs->total_sectors); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| return bs->total_sectors; |
| } |
| |
| /** |
| * Return length in bytes on success, -errno on error. |
| * The length is always a multiple of BDRV_SECTOR_SIZE. |
| */ |
| int64_t bdrv_getlength(BlockDriverState *bs) |
| { |
| int64_t ret = bdrv_nb_sectors(bs); |
| |
| ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret; |
| return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE; |
| } |
| |
| /* return 0 as number of sectors if no device present or error */ |
| void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) |
| { |
| int64_t nb_sectors = bdrv_nb_sectors(bs); |
| |
| *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors; |
| } |
| |
| bool bdrv_is_sg(BlockDriverState *bs) |
| { |
| return bs->sg; |
| } |
| |
| bool bdrv_is_encrypted(BlockDriverState *bs) |
| { |
| if (bs->backing && bs->backing->bs->encrypted) { |
| return true; |
| } |
| return bs->encrypted; |
| } |
| |
| const char *bdrv_get_format_name(BlockDriverState *bs) |
| { |
| return bs->drv ? bs->drv->format_name : NULL; |
| } |
| |
| static int qsort_strcmp(const void *a, const void *b) |
| { |
| return strcmp(*(char *const *)a, *(char *const *)b); |
| } |
| |
| void bdrv_iterate_format(void (*it)(void *opaque, const char *name), |
| void *opaque, bool read_only) |
| { |
| BlockDriver *drv; |
| int count = 0; |
| int i; |
| const char **formats = NULL; |
| |
| QLIST_FOREACH(drv, &bdrv_drivers, list) { |
| if (drv->format_name) { |
| bool found = false; |
| int i = count; |
| |
| if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, read_only)) { |
| continue; |
| } |
| |
| while (formats && i && !found) { |
| found = !strcmp(formats[--i], drv->format_name); |
| } |
| |
| if (!found) { |
| formats = g_renew(const char *, formats, count + 1); |
| formats[count++] = drv->format_name; |
| } |
| } |
| } |
| |
| for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) { |
| const char *format_name = block_driver_modules[i].format_name; |
| |
| if (format_name) { |
| bool found = false; |
| int j = count; |
| |
| if (use_bdrv_whitelist && |
| !bdrv_format_is_whitelisted(format_name, read_only)) { |
| continue; |
| } |
| |
| while (formats && j && !found) { |
| found = !strcmp(formats[--j], format_name); |
| } |
| |
| if (!found) { |
| formats = g_renew(const char *, formats, count + 1); |
| formats[count++] = format_name; |
| } |
| } |
| } |
| |
| qsort(formats, count, sizeof(formats[0]), qsort_strcmp); |
| |
| for (i = 0; i < count; i++) { |
| it(opaque, formats[i]); |
| } |
| |
| g_free(formats); |
| } |
| |
| /* This function is to find a node in the bs graph */ |
| BlockDriverState *bdrv_find_node(const char *node_name) |
| { |
| BlockDriverState *bs; |
| |
| assert(node_name); |
| |
| QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { |
| if (!strcmp(node_name, bs->node_name)) { |
| return bs; |
| } |
| } |
| return NULL; |
| } |
| |
| /* Put this QMP function here so it can access the static graph_bdrv_states. */ |
| BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, |
| Error **errp) |
| { |
| BlockDeviceInfoList *list, *entry; |
| BlockDriverState *bs; |
| |
| list = NULL; |
| QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { |
| BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, flat, errp); |
| if (!info) { |
| qapi_free_BlockDeviceInfoList(list); |
| return NULL; |
| } |
| entry = g_malloc0(sizeof(*entry)); |
| entry->value = info; |
| entry->next = list; |
| list = entry; |
| } |
| |
| return list; |
| } |
| |
| #define QAPI_LIST_ADD(list, element) do { \ |
| typeof(list) _tmp = g_new(typeof(*(list)), 1); \ |
| _tmp->value = (element); \ |
| _tmp->next = (list); \ |
| (list) = _tmp; \ |
| } while (0) |
| |
| typedef struct XDbgBlockGraphConstructor { |
| XDbgBlockGraph *graph; |
| GHashTable *graph_nodes; |
| } XDbgBlockGraphConstructor; |
| |
| static XDbgBlockGraphConstructor *xdbg_graph_new(void) |
| { |
| XDbgBlockGraphConstructor *gr = g_new(XDbgBlockGraphConstructor, 1); |
| |
| gr->graph = g_new0(XDbgBlockGraph, 1); |
| gr->graph_nodes = g_hash_table_new(NULL, NULL); |
| |
| return gr; |
| } |
| |
| static XDbgBlockGraph *xdbg_graph_finalize(XDbgBlockGraphConstructor *gr) |
| { |
| XDbgBlockGraph *graph = gr->graph; |
| |
| g_hash_table_destroy(gr->graph_nodes); |
| g_free(gr); |
| |
| return graph; |
| } |
| |
| static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor *gr, void *node) |
| { |
| uintptr_t ret = (uintptr_t)g_hash_table_lookup(gr->graph_nodes, node); |
| |
| if (ret != 0) { |
| return ret; |
| } |
| |
| /* |
| * Start counting from 1, not 0, because 0 interferes with not-found (NULL) |
| * answer of g_hash_table_lookup. |
| */ |
| ret = g_hash_table_size(gr->graph_nodes) + 1; |
| g_hash_table_insert(gr->graph_nodes, node, (void *)ret); |
| |
| return ret; |
| } |
| |
| static void xdbg_graph_add_node(XDbgBlockGraphConstructor *gr, void *node, |
| XDbgBlockGraphNodeType type, const char *name) |
| { |
| XDbgBlockGraphNode *n; |
| |
| n = g_new0(XDbgBlockGraphNode, 1); |
| |
| n->id = xdbg_graph_node_num(gr, node); |
| n->type = type; |
| n->name = g_strdup(name); |
| |
| QAPI_LIST_ADD(gr->graph->nodes, n); |
| } |
| |
| static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *gr, void *parent, |
| const BdrvChild *child) |
| { |
| BlockPermission qapi_perm; |
| XDbgBlockGraphEdge *edge; |
| |
| edge = g_new0(XDbgBlockGraphEdge, 1); |
| |
| edge->parent = xdbg_graph_node_num(gr, parent); |
| edge->child = xdbg_graph_node_num(gr, child->bs); |
| edge->name = g_strdup(child->name); |
| |
| for (qapi_perm = 0; qapi_perm < BLOCK_PERMISSION__MAX; qapi_perm++) { |
| uint64_t flag = bdrv_qapi_perm_to_blk_perm(qapi_perm); |
| |
| if (flag & child->perm) { |
| QAPI_LIST_ADD(edge->perm, qapi_perm); |
| } |
| if (flag & child->shared_perm) { |
| QAPI_LIST_ADD(edge->shared_perm, qapi_perm); |
| } |
| } |
| |
| QAPI_LIST_ADD(gr->graph->edges, edge); |
| } |
| |
| |
| XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp) |
| { |
| BlockBackend *blk; |
| BlockJob *job; |
| BlockDriverState *bs; |
| BdrvChild *child; |
| XDbgBlockGraphConstructor *gr = xdbg_graph_new(); |
| |
| for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) { |
| char *allocated_name = NULL; |
| const char *name = blk_name(blk); |
| |
| if (!*name) { |
| name = allocated_name = blk_get_attached_dev_id(blk); |
| } |
| xdbg_graph_add_node(gr, blk, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND, |
| name); |
| g_free(allocated_name); |
| if (blk_root(blk)) { |
| xdbg_graph_add_edge(gr, blk, blk_root(blk)); |
| } |
| } |
| |
| for (job = block_job_next(NULL); job; job = block_job_next(job)) { |
| GSList *el; |
| |
| xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB, |
| job->job.id); |
| for (el = job->nodes; el; el = el->next) { |
| xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data); |
| } |
| } |
| |
| QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { |
| xdbg_graph_add_node(gr, bs, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER, |
| bs->node_name); |
| QLIST_FOREACH(child, &bs->children, next) { |
| xdbg_graph_add_edge(gr, bs, child); |
| } |
| } |
| |
| return xdbg_graph_finalize(gr); |
| } |
| |
| BlockDriverState *bdrv_lookup_bs(const char *device, |
| const char *node_name, |
| Error **errp) |
| { |
| BlockBackend *blk; |
| BlockDriverState *bs; |
| |
| if (device) { |
| blk = blk_by_name(device); |
| |
| if (blk) { |
| bs = blk_bs(blk); |
| if (!bs) { |
| error_setg(errp, "Device '%s' has no medium", device); |
| } |
| |
| return bs; |
| } |
| } |
| |
| if (node_name) { |
| bs = bdrv_find_node(node_name); |
| |
| if (bs) { |
| return bs; |
| } |
| } |
| |
| error_setg(errp, "Cannot find device=%s nor node_name=%s", |
| device ? device : "", |
| node_name ? node_name : ""); |
| return NULL; |
| } |
| |
| /* If 'base' is in the same chain as 'top', return true. Otherwise, |
| * return false. If either argument is NULL, return false. */ |
| bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) |
| { |
| while (top && top != base) { |
| top = backing_bs(top); |
| } |
| |
| return top != NULL; |
| } |
| |
| BlockDriverState *bdrv_next_node(BlockDriverState *bs) |
| { |
| if (!bs) { |
| return QTAILQ_FIRST(&graph_bdrv_states); |
| } |
| return QTAILQ_NEXT(bs, node_list); |
| } |
| |
| BlockDriverState *bdrv_next_all_states(BlockDriverState *bs) |
| { |
| if (!bs) { |
| return QTAILQ_FIRST(&all_bdrv_states); |
| } |
| return QTAILQ_NEXT(bs, bs_list); |
| } |
| |
| const char *bdrv_get_node_name(const BlockDriverState *bs) |
| { |
| return bs->node_name; |
| } |
| |
| const char *bdrv_get_parent_name(const BlockDriverState *bs) |
| { |
| BdrvChild *c; |
| const char *name; |
| |
| /* If multiple parents have a name, just pick the first one. */ |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| if (c->klass->get_name) { |
| name = c->klass->get_name(c); |
| if (name && *name) { |
| return name; |
| } |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /* TODO check what callers really want: bs->node_name or blk_name() */ |
| const char *bdrv_get_device_name(const BlockDriverState *bs) |
| { |
| return bdrv_get_parent_name(bs) ?: ""; |
| } |
| |
| /* This can be used to identify nodes that might not have a device |
| * name associated. Since node and device names live in the same |
| * namespace, the result is unambiguous. The exception is if both are |
| * absent, then this returns an empty (non-null) string. */ |
| const char *bdrv_get_device_or_node_name(const BlockDriverState *bs) |
| { |
| return bdrv_get_parent_name(bs) ?: bs->node_name; |
| } |
| |
| int bdrv_get_flags(BlockDriverState *bs) |
| { |
| return bs->open_flags; |
| } |
| |
| int bdrv_has_zero_init_1(BlockDriverState *bs) |
| { |
| return 1; |
| } |
| |
| int bdrv_has_zero_init(BlockDriverState *bs) |
| { |
| if (!bs->drv) { |
| return 0; |
| } |
| |
| /* If BS is a copy on write image, it is initialized to |
| the contents of the base image, which may not be zeroes. */ |
| if (bs->backing) { |
| return 0; |
| } |
| if (bs->drv->bdrv_has_zero_init) { |
| return bs->drv->bdrv_has_zero_init(bs); |
| } |
| if (bs->file && bs->drv->is_filter) { |
| return bdrv_has_zero_init(bs->file->bs); |
| } |
| |
| /* safe default */ |
| return 0; |
| } |
| |
| bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) |
| { |
| if (!(bs->open_flags & BDRV_O_UNMAP)) { |
| return false; |
| } |
| |
| return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP; |
| } |
| |
| void bdrv_get_backing_filename(BlockDriverState *bs, |
| char *filename, int filename_size) |
| { |
| pstrcpy(filename, filename_size, bs->backing_file); |
| } |
| |
| int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) |
| { |
| BlockDriver *drv = bs->drv; |
| /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ |
| if (!drv) { |
| return -ENOMEDIUM; |
| } |
| if (!drv->bdrv_get_info) { |
| if (bs->file && drv->is_filter) { |
| return bdrv_get_info(bs->file->bs, bdi); |
| } |
| return -ENOTSUP; |
| } |
| memset(bdi, 0, sizeof(*bdi)); |
| return drv->bdrv_get_info(bs, bdi); |
| } |
| |
| ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs, |
| Error **errp) |
| { |
| BlockDriver *drv = bs->drv; |
| if (drv && drv->bdrv_get_specific_info) { |
| return drv->bdrv_get_specific_info(bs, errp); |
| } |
| return NULL; |
| } |
| |
| BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs) |
| { |
| BlockDriver *drv = bs->drv; |
| if (!drv || !drv->bdrv_get_specific_stats) { |
| return NULL; |
| } |
| return drv->bdrv_get_specific_stats(bs); |
| } |
| |
| void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event) |
| { |
| if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { |
| return; |
| } |
| |
| bs->drv->bdrv_debug_event(bs, event); |
| } |
| |
| static BlockDriverState *bdrv_find_debug_node(BlockDriverState *bs) |
| { |
| while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { |
| if (bs->file) { |
| bs = bs->file->bs; |
| continue; |
| } |
| |
| if (bs->drv->is_filter && bs->backing) { |
| bs = bs->backing->bs; |
| continue; |
| } |
| |
| break; |
| } |
| |
| if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { |
| assert(bs->drv->bdrv_debug_remove_breakpoint); |
| return bs; |
| } |
| |
| return NULL; |
| } |
| |
| int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, |
| const char *tag) |
| { |
| bs = bdrv_find_debug_node(bs); |
| if (bs) { |
| return bs->drv->bdrv_debug_breakpoint(bs, event, tag); |
| } |
| |
| return -ENOTSUP; |
| } |
| |
| int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) |
| { |
| bs = bdrv_find_debug_node(bs); |
| if (bs) { |
| return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); |
| } |
| |
| return -ENOTSUP; |
| } |
| |
| int bdrv_debug_resume(BlockDriverState *bs, const char *tag) |
| { |
| while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) { |
| bs = bs->file ? bs->file->bs : NULL; |
| } |
| |
| if (bs && bs->drv && bs->drv->bdrv_debug_resume) { |
| return bs->drv->bdrv_debug_resume(bs, tag); |
| } |
| |
| return -ENOTSUP; |
| } |
| |
| bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) |
| { |
| while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { |
| bs = bs->file ? bs->file->bs : NULL; |
| } |
| |
| if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { |
| return bs->drv->bdrv_debug_is_suspended(bs, tag); |
| } |
| |
| return false; |
| } |
| |
| /* backing_file can either be relative, or absolute, or a protocol. If it is |
| * relative, it must be relative to the chain. So, passing in bs->filename |
| * from a BDS as backing_file should not be done, as that may be relative to |
| * the CWD rather than the chain. */ |
| BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, |
| const char *backing_file) |
| { |
| char *filename_full = NULL; |
| char *backing_file_full = NULL; |
| char *filename_tmp = NULL; |
| int is_protocol = 0; |
| BlockDriverState *curr_bs = NULL; |
| BlockDriverState *retval = NULL; |
| |
| if (!bs || !bs->drv || !backing_file) { |
| return NULL; |
| } |
| |
| filename_full = g_malloc(PATH_MAX); |
| backing_file_full = g_malloc(PATH_MAX); |
| |
| is_protocol = path_has_protocol(backing_file); |
| |
| for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) { |
| |
| /* If either of the filename paths is actually a protocol, then |
| * compare unmodified paths; otherwise make paths relative */ |
| if (is_protocol || path_has_protocol(curr_bs->backing_file)) { |
| char *backing_file_full_ret; |
| |
| if (strcmp(backing_file, curr_bs->backing_file) == 0) { |
| retval = curr_bs->backing->bs; |
| break; |
| } |
| /* Also check against the full backing filename for the image */ |
| backing_file_full_ret = bdrv_get_full_backing_filename(curr_bs, |
| NULL); |
| if (backing_file_full_ret) { |
| bool equal = strcmp(backing_file, backing_file_full_ret) == 0; |
| g_free(backing_file_full_ret); |
| if (equal) { |
| retval = curr_bs->backing->bs; |
| break; |
| } |
| } |
| } else { |
| /* If not an absolute filename path, make it relative to the current |
| * image's filename path */ |
| filename_tmp = bdrv_make_absolute_filename(curr_bs, backing_file, |
| NULL); |
| /* We are going to compare canonicalized absolute pathnames */ |
| if (!filename_tmp || !realpath(filename_tmp, filename_full)) { |
| g_free(filename_tmp); |
| continue; |
| } |
| g_free(filename_tmp); |
| |
| /* We need to make sure the backing filename we are comparing against |
| * is relative to the current image filename (or absolute) */ |
| filename_tmp = bdrv_get_full_backing_filename(curr_bs, NULL); |
| if (!filename_tmp || !realpath(filename_tmp, backing_file_full)) { |
| g_free(filename_tmp); |
| continue; |
| } |
| g_free(filename_tmp); |
| |
| if (strcmp(backing_file_full, filename_full) == 0) { |
| retval = curr_bs->backing->bs; |
| break; |
| } |
| } |
| } |
| |
| g_free(filename_full); |
| g_free(backing_file_full); |
| return retval; |
| } |
| |
| void bdrv_init(void) |
| { |
| module_call_init(MODULE_INIT_BLOCK); |
| } |
| |
| void bdrv_init_with_whitelist(void) |
| { |
| use_bdrv_whitelist = 1; |
| bdrv_init(); |
| } |
| |
| static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, |
| Error **errp) |
| { |
| BdrvChild *child, *parent; |
| uint64_t perm, shared_perm; |
| Error *local_err = NULL; |
| int ret; |
| BdrvDirtyBitmap *bm; |
| |
| if (!bs->drv) { |
| return; |
| } |
| |
| QLIST_FOREACH(child, &bs->children, next) { |
| bdrv_co_invalidate_cache(child->bs, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return; |
| } |
| } |
| |
| /* |
| * Update permissions, they may differ for inactive nodes. |
| * |
| * Note that the required permissions of inactive images are always a |
| * subset of the permissions required after activating the image. This |
| * allows us to just get the permissions upfront without restricting |
| * drv->bdrv_invalidate_cache(). |
| * |
| * It also means that in error cases, we don't have to try and revert to |
| * the old permissions (which is an operation that could fail, too). We can |
| * just keep the extended permissions for the next time that an activation |
| * of the image is tried. |
| */ |
| if (bs->open_flags & BDRV_O_INACTIVE) { |
| bs->open_flags &= ~BDRV_O_INACTIVE; |
| bdrv_get_cumulative_perm(bs, &perm, &shared_perm); |
| ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, errp); |
| if (ret < 0) { |
| bs->open_flags |= BDRV_O_INACTIVE; |
| return; |
| } |
| bdrv_set_perm(bs, perm, shared_perm); |
| |
| if (bs->drv->bdrv_co_invalidate_cache) { |
| bs->drv->bdrv_co_invalidate_cache(bs, &local_err); |
| if (local_err) { |
| bs->open_flags |= BDRV_O_INACTIVE; |
| error_propagate(errp, local_err); |
| return; |
| } |
| } |
| |
| FOR_EACH_DIRTY_BITMAP(bs, bm) { |
| bdrv_dirty_bitmap_skip_store(bm, false); |
| } |
| |
| ret = refresh_total_sectors(bs, bs->total_sectors); |
| if (ret < 0) { |
| bs->open_flags |= BDRV_O_INACTIVE; |
| error_setg_errno(errp, -ret, "Could not refresh total sector count"); |
| return; |
| } |
| } |
| |
| QLIST_FOREACH(parent, &bs->parents, next_parent) { |
| if (parent->klass->activate) { |
| parent->klass->activate(parent, &local_err); |
| if (local_err) { |
| bs->open_flags |= BDRV_O_INACTIVE; |
| error_propagate(errp, local_err); |
| return; |
| } |
| } |
| } |
| } |
| |
| typedef struct InvalidateCacheCo { |
| BlockDriverState *bs; |
| Error **errp; |
| bool done; |
| } InvalidateCacheCo; |
| |
| static void coroutine_fn bdrv_invalidate_cache_co_entry(void *opaque) |
| { |
| InvalidateCacheCo *ico = opaque; |
| bdrv_co_invalidate_cache(ico->bs, ico->errp); |
| ico->done = true; |
| aio_wait_kick(); |
| } |
| |
| void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) |
| { |
| Coroutine *co; |
| InvalidateCacheCo ico = { |
| .bs = bs, |
| .done = false, |
| .errp = errp |
| }; |
| |
| if (qemu_in_coroutine()) { |
| /* Fast-path if already in coroutine context */ |
| bdrv_invalidate_cache_co_entry(&ico); |
| } else { |
| co = qemu_coroutine_create(bdrv_invalidate_cache_co_entry, &ico); |
| bdrv_coroutine_enter(bs, co); |
| BDRV_POLL_WHILE(bs, !ico.done); |
| } |
| } |
| |
| void bdrv_invalidate_cache_all(Error **errp) |
| { |
| BlockDriverState *bs; |
| Error *local_err = NULL; |
| BdrvNextIterator it; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *aio_context = bdrv_get_aio_context(bs); |
| |
| aio_context_acquire(aio_context); |
| bdrv_invalidate_cache(bs, &local_err); |
| aio_context_release(aio_context); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| bdrv_next_cleanup(&it); |
| return; |
| } |
| } |
| } |
| |
| static bool bdrv_has_bds_parent(BlockDriverState *bs, bool only_active) |
| { |
| BdrvChild *parent; |
| |
| QLIST_FOREACH(parent, &bs->parents, next_parent) { |
| if (parent->klass->parent_is_bds) { |
| BlockDriverState *parent_bs = parent->opaque; |
| if (!only_active || !(parent_bs->open_flags & BDRV_O_INACTIVE)) { |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| static int bdrv_inactivate_recurse(BlockDriverState *bs) |
| { |
| BdrvChild *child, *parent; |
| bool tighten_restrictions; |
| uint64_t perm, shared_perm; |
| int ret; |
| |
| if (!bs->drv) { |
| return -ENOMEDIUM; |
| } |
| |
| /* Make sure that we don't inactivate a child before its parent. |
| * It will be covered by recursion from the yet active parent. */ |
| if (bdrv_has_bds_parent(bs, true)) { |
| return 0; |
| } |
| |
| assert(!(bs->open_flags & BDRV_O_INACTIVE)); |
| |
| /* Inactivate this node */ |
| if (bs->drv->bdrv_inactivate) { |
| ret = bs->drv->bdrv_inactivate(bs); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| |
| QLIST_FOREACH(parent, &bs->parents, next_parent) { |
| if (parent->klass->inactivate) { |
| ret = parent->klass->inactivate(parent); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| } |
| |
| bs->open_flags |= BDRV_O_INACTIVE; |
| |
| /* Update permissions, they may differ for inactive nodes */ |
| bdrv_get_cumulative_perm(bs, &perm, &shared_perm); |
| ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, |
| &tighten_restrictions, NULL); |
| assert(tighten_restrictions == false); |
| if (ret < 0) { |
| /* We only tried to loosen restrictions, so errors are not fatal */ |
| bdrv_abort_perm_update(bs); |
| } else { |
| bdrv_set_perm(bs, perm, shared_perm); |
| } |
| |
| |
| /* Recursively inactivate children */ |
| QLIST_FOREACH(child, &bs->children, next) { |
| ret = bdrv_inactivate_recurse(child->bs); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| int bdrv_inactivate_all(void) |
| { |
| BlockDriverState *bs = NULL; |
| BdrvNextIterator it; |
| int ret = 0; |
| GSList *aio_ctxs = NULL, *ctx; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *aio_context = bdrv_get_aio_context(bs); |
| |
| if (!g_slist_find(aio_ctxs, aio_context)) { |
| aio_ctxs = g_slist_prepend(aio_ctxs, aio_context); |
| aio_context_acquire(aio_context); |
| } |
| } |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| /* Nodes with BDS parents are covered by recursion from the last |
| * parent that gets inactivated. Don't inactivate them a second |
| * time if that has already happened. */ |
| if (bdrv_has_bds_parent(bs, false)) { |
| continue; |
| } |
| ret = bdrv_inactivate_recurse(bs); |
| if (ret < 0) { |
| bdrv_next_cleanup(&it); |
| goto out; |
| } |
| } |
| |
| out: |
| for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) { |
| AioContext *aio_context = ctx->data; |
| aio_context_release(aio_context); |
| } |
| g_slist_free(aio_ctxs); |
| |
| return ret; |
| } |
| |
| /**************************************************************/ |
| /* removable device support */ |
| |
| /** |
| * Return TRUE if the media is present |
| */ |
| bool bdrv_is_inserted(BlockDriverState *bs) |
| { |
| BlockDriver *drv = bs->drv; |
| BdrvChild *child; |
| |
| if (!drv) { |
| return false; |
| } |
| if (drv->bdrv_is_inserted) { |
| return drv->bdrv_is_inserted(bs); |
| } |
| QLIST_FOREACH(child, &bs->children, next) { |
| if (!bdrv_is_inserted(child->bs)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * If eject_flag is TRUE, eject the media. Otherwise, close the tray |
| */ |
| void bdrv_eject(BlockDriverState *bs, bool eject_flag) |
| { |
| BlockDriver *drv = bs->drv; |
| |
| if (drv && drv->bdrv_eject) { |
| drv->bdrv_eject(bs, eject_flag); |
| } |
| } |
| |
| /** |
| * Lock or unlock the media (if it is locked, the user won't be able |
| * to eject it manually). |
| */ |
| void bdrv_lock_medium(BlockDriverState *bs, bool locked) |
| { |
| BlockDriver *drv = bs->drv; |
| |
| trace_bdrv_lock_medium(bs, locked); |
| |
| if (drv && drv->bdrv_lock_medium) { |
| drv->bdrv_lock_medium(bs, locked); |
| } |
| } |
| |
| /* Get a reference to bs */ |
| void bdrv_ref(BlockDriverState *bs) |
| { |
| bs->refcnt++; |
| } |
| |
| /* Release a previously grabbed reference to bs. |
| * If after releasing, reference count is zero, the BlockDriverState is |
| * deleted. */ |
| void bdrv_unref(BlockDriverState *bs) |
| { |
| if (!bs) { |
| return; |
| } |
| assert(bs->refcnt > 0); |
| if (--bs->refcnt == 0) { |
| bdrv_delete(bs); |
| } |
| } |
| |
| struct BdrvOpBlocker { |
| Error *reason; |
| QLIST_ENTRY(BdrvOpBlocker) list; |
| }; |
| |
| bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) |
| { |
| BdrvOpBlocker *blocker; |
| assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); |
| if (!QLIST_EMPTY(&bs->op_blockers[op])) { |
| blocker = QLIST_FIRST(&bs->op_blockers[op]); |
| error_propagate_prepend(errp, error_copy(blocker->reason), |
| "Node '%s' is busy: ", |
| bdrv_get_device_or_node_name(bs)); |
| return true; |
| } |
| return false; |
| } |
| |
| void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason) |
| { |
| BdrvOpBlocker *blocker; |
| assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); |
| |
| blocker = g_new0(BdrvOpBlocker, 1); |
| blocker->reason = reason; |
| QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list); |
| } |
| |
| void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason) |
| { |
| BdrvOpBlocker *blocker, *next; |
| assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); |
| QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) { |
| if (blocker->reason == reason) { |
| QLIST_REMOVE(blocker, list); |
| g_free(blocker); |
| } |
| } |
| } |
| |
| void bdrv_op_block_all(BlockDriverState *bs, Error *reason) |
| { |
| int i; |
| for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { |
| bdrv_op_block(bs, i, reason); |
| } |
| } |
| |
| void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason) |
| { |
| int i; |
| for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { |
| bdrv_op_unblock(bs, i, reason); |
| } |
| } |
| |
| bool bdrv_op_blocker_is_empty(BlockDriverState *bs) |
| { |
| int i; |
| |
| for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { |
| if (!QLIST_EMPTY(&bs->op_blockers[i])) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| void bdrv_img_create(const char *filename, const char *fmt, |
| const char *base_filename, const char *base_fmt, |
| char *options, uint64_t img_size, int flags, bool quiet, |
| Error **errp) |
| { |
| QemuOptsList *create_opts = NULL; |
| QemuOpts *opts = NULL; |
| const char *backing_fmt, *backing_file; |
| int64_t size; |
| BlockDriver *drv, *proto_drv; |
| Error *local_err = NULL; |
| int ret = 0; |
| |
| /* Find driver and parse its options */ |
| drv = bdrv_find_format(fmt); |
| if (!drv) { |
| error_setg(errp, "Unknown file format '%s'", fmt); |
| return; |
| } |
| |
| proto_drv = bdrv_find_protocol(filename, true, errp); |
| if (!proto_drv) { |
| return; |
| } |
| |
| if (!drv->create_opts) { |
| error_setg(errp, "Format driver '%s' does not support image creation", |
| drv->format_name); |
| return; |
| } |
| |
| if (!proto_drv->create_opts) { |
| error_setg(errp, "Protocol driver '%s' does not support image creation", |
| proto_drv->format_name); |
| return; |
| } |
| |
| /* Create parameter list */ |
| create_opts = qemu_opts_append(create_opts, drv->create_opts); |
| create_opts = qemu_opts_append(create_opts, proto_drv->create_opts); |
| |
| opts = qemu_opts_create(create_opts, NULL, 0, &error_abort); |
| |
| /* Parse -o options */ |
| if (options) { |
| if (!qemu_opts_do_parse(opts, options, NULL, errp)) { |
| goto out; |
| } |
| } |
| |
| if (!qemu_opt_get(opts, BLOCK_OPT_SIZE)) { |
| qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort); |
| } else if (img_size != UINT64_C(-1)) { |
| error_setg(errp, "The image size must be specified only once"); |
| goto out; |
| } |
| |
| if (base_filename) { |
| if (!qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, |
| NULL)) { |
| error_setg(errp, "Backing file not supported for file format '%s'", |
| fmt); |
| goto out; |
| } |
| } |
| |
| if (base_fmt) { |
| if (!qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, NULL)) { |
| error_setg(errp, "Backing file format not supported for file " |
| "format '%s'", fmt); |
| goto out; |
| } |
| } |
| |
| backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); |
| if (backing_file) { |
| if (!strcmp(filename, backing_file)) { |
| error_setg(errp, "Error: Trying to create an image with the " |
| "same filename as the backing file"); |
| goto out; |
| } |
| } |
| |
| backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); |
| |
| /* The size for the image must always be specified, unless we have a backing |
| * file and we have not been forbidden from opening it. */ |
| size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size); |
| if (backing_file && !(flags & BDRV_O_NO_BACKING)) { |
| BlockDriverState *bs; |
| char *full_backing; |
| int back_flags; |
| QDict *backing_options = NULL; |
| |
| full_backing = |
| bdrv_get_full_backing_filename_from_filename(filename, backing_file, |
| &local_err); |
| if (local_err) { |
| goto out; |
| } |
| assert(full_backing); |
| |
| /* backing files always opened read-only */ |
| back_flags = flags; |
| back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); |
| |
| backing_options = qdict_new(); |
| if (backing_fmt) { |
| qdict_put_str(backing_options, "driver", backing_fmt); |
| } |
| qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true); |
| |
| bs = bdrv_open(full_backing, NULL, backing_options, back_flags, |
| &local_err); |
| g_free(full_backing); |
| if (!bs && size != -1) { |
| /* Couldn't open BS, but we have a size, so it's nonfatal */ |
| warn_reportf_err(local_err, |
| "Could not verify backing image. " |
| "This may become an error in future versions.\n"); |
| local_err = NULL; |
| } else if (!bs) { |
| /* Couldn't open bs, do not have size */ |
| error_append_hint(&local_err, |
| "Could not open backing image to determine size.\n"); |
| goto out; |
| } else { |
| if (size == -1) { |
| /* Opened BS, have no size */ |
| size = bdrv_getlength(bs); |
| if (size < 0) { |
| error_setg_errno(errp, -size, "Could not get size of '%s'", |
| backing_file); |
| bdrv_unref(bs); |
| goto out; |
| } |
| qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort); |
| } |
| bdrv_unref(bs); |
| } |
| } /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */ |
| |
| if (size == -1) { |
| error_setg(errp, "Image creation needs a size parameter"); |
| goto out; |
| } |
| |
| if (!quiet) { |
| printf("Formatting '%s', fmt=%s ", filename, fmt); |
| qemu_opts_print(opts, " "); |
| puts(""); |
| } |
| |
| ret = bdrv_create(drv, filename, opts, &local_err); |
| |
| if (ret == -EFBIG) { |
| /* This is generally a better message than whatever the driver would |
| * deliver (especially because of the cluster_size_hint), since that |
| * is most probably not much different from "image too large". */ |
| const char *cluster_size_hint = ""; |
| if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) { |
| cluster_size_hint = " (try using a larger cluster size)"; |
| } |
| error_setg(errp, "The image size is too large for file format '%s'" |
| "%s", fmt, cluster_size_hint); |
| error_free(local_err); |
| local_err = NULL; |
| } |
| |
| out: |
| qemu_opts_del(opts); |
| qemu_opts_free(create_opts); |
| error_propagate(errp, local_err); |
| } |
| |
| AioContext *bdrv_get_aio_context(BlockDriverState *bs) |
| { |
| return bs ? bs->aio_context : qemu_get_aio_context(); |
| } |
| |
| void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co) |
| { |
| aio_co_enter(bdrv_get_aio_context(bs), co); |
| } |
| |
| static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban) |
| { |
| QLIST_REMOVE(ban, list); |
| g_free(ban); |
| } |
| |
| static void bdrv_detach_aio_context(BlockDriverState *bs) |
| { |
| BdrvAioNotifier *baf, *baf_tmp; |
| |
| assert(!bs->walking_aio_notifiers); |
| bs->walking_aio_notifiers = true; |
| QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) { |
| if (baf->deleted) { |
| bdrv_do_remove_aio_context_notifier(baf); |
| } else { |
| baf->detach_aio_context(baf->opaque); |
| } |
| } |
| /* Never mind iterating again to check for ->deleted. bdrv_close() will |
| * remove remaining aio notifiers if we aren't called again. |
| */ |
| bs->walking_aio_notifiers = false; |
| |
| if (bs->drv && bs->drv->bdrv_detach_aio_context) { |
| bs->drv->bdrv_detach_aio_context(bs); |
| } |
| |
| if (bs->quiesce_counter) { |
| aio_enable_external(bs->aio_context); |
| } |
| bs->aio_context = NULL; |
| } |
| |
| static void bdrv_attach_aio_context(BlockDriverState *bs, |
| AioContext *new_context) |
| { |
| BdrvAioNotifier *ban, *ban_tmp; |
| |
| if (bs->quiesce_counter) { |
| aio_disable_external(new_context); |
| } |
| |
| bs->aio_context = new_context; |
| |
| if (bs->drv && bs->drv->bdrv_attach_aio_context) { |
| bs->drv->bdrv_attach_aio_context(bs, new_context); |
| } |
| |
| assert(!bs->walking_aio_notifiers); |
| bs->walking_aio_notifiers = true; |
| QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) { |
| if (ban->deleted) { |
| bdrv_do_remove_aio_context_notifier(ban); |
| } else { |
| ban->attached_aio_context(new_context, ban->opaque); |
| } |
| } |
| bs->walking_aio_notifiers = false; |
| } |
| |
| /* |
| * Changes the AioContext used for fd handlers, timers, and BHs by this |
| * BlockDriverState and all its children and parents. |
| * |
| * Must be called from the main AioContext. |
| * |
| * The caller must own the AioContext lock for the old AioContext of bs, but it |
| * must not own the AioContext lock for new_context (unless new_context is the |
| * same as the current context of bs). |
| * |
| * @ignore will accumulate all visited BdrvChild object. The caller is |
| * responsible for freeing the list afterwards. |
| */ |
| void bdrv_set_aio_context_ignore(BlockDriverState *bs, |
| AioContext *new_context, GSList **ignore) |
| { |
| AioContext *old_context = bdrv_get_aio_context(bs); |
| BdrvChild *child; |
| |
| g_assert(qemu_get_current_aio_context() == qemu_get_aio_context()); |
| |
| if (old_context == new_context) { |
| return; |
| } |
| |
| bdrv_drained_begin(bs); |
| |
| QLIST_FOREACH(child, &bs->children, next) { |
| if (g_slist_find(*ignore, child)) { |
| continue; |
| } |
| *ignore = g_slist_prepend(*ignore, child); |
| bdrv_set_aio_context_ignore(child->bs, new_context, ignore); |
| } |
| QLIST_FOREACH(child, &bs->parents, next_parent) { |
| if (g_slist_find(*ignore, child)) { |
| continue; |
| } |
| assert(child->klass->set_aio_ctx); |
| *ignore = g_slist_prepend(*ignore, child); |
| child->klass->set_aio_ctx(child, new_context, ignore); |
| } |
| |
| bdrv_detach_aio_context(bs); |
| |
| /* Acquire the new context, if necessary */ |
| if (qemu_get_aio_context() != new_context) { |
| aio_context_acquire(new_context); |
| } |
| |
| bdrv_attach_aio_context(bs, new_context); |
| |
| /* |
| * If this function was recursively called from |
| * bdrv_set_aio_context_ignore(), there may be nodes in the |
| * subtree that have not yet been moved to the new AioContext. |
| * Release the old one so bdrv_drained_end() can poll them. |
| */ |
| if (qemu_get_aio_context() != old_context) { |
| aio_context_release(old_context); |
| } |
| |
| bdrv_drained_end(bs); |
| |
| if (qemu_get_aio_context() != old_context) { |
| aio_context_acquire(old_context); |
| } |
| if (qemu_get_aio_context() != new_context) { |
| aio_context_release(new_context); |
| } |
| } |
| |
| static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx, |
| GSList **ignore, Error **errp) |
| { |
| if (g_slist_find(*ignore, c)) { |
| return true; |
| } |
| *ignore = g_slist_prepend(*ignore, c); |
| |
| /* |
| * A BdrvChildClass that doesn't handle AioContext changes cannot |
| * tolerate any AioContext changes |
| */ |
| if (!c->klass->can_set_aio_ctx) { |
| char *user = bdrv_child_user_desc(c); |
| error_setg(errp, "Changing iothreads is not supported by %s", user); |
| g_free(user); |
| return false; |
| } |
| if (!c->klass->can_set_aio_ctx(c, ctx, ignore, errp)) { |
| assert(!errp || *errp); |
| return false; |
| } |
| return true; |
| } |
| |
| bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx, |
| GSList **ignore, Error **errp) |
| { |
| if (g_slist_find(*ignore, c)) { |
| return true; |
| } |
| *ignore = g_slist_prepend(*ignore, c); |
| return bdrv_can_set_aio_context(c->bs, ctx, ignore, errp); |
| } |
| |
| /* @ignore will accumulate all visited BdrvChild object. The caller is |
| * responsible for freeing the list afterwards. */ |
| bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx, |
| GSList **ignore, Error **errp) |
| { |
| BdrvChild *c; |
| |
| if (bdrv_get_aio_context(bs) == ctx) { |
| return true; |
| } |
| |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| if (!bdrv_parent_can_set_aio_context(c, ctx, ignore, errp)) { |
| return false; |
| } |
| } |
| QLIST_FOREACH(c, &bs->children, next) { |
| if (!bdrv_child_can_set_aio_context(c, ctx, ignore, errp)) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx, |
| BdrvChild *ignore_child, Error **errp) |
| { |
| GSList *ignore; |
| bool ret; |
| |
| ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL; |
| ret = bdrv_can_set_aio_context(bs, ctx, &ignore, errp); |
| g_slist_free(ignore); |
| |
| if (!ret) { |
| return -EPERM; |
| } |
| |
| ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL; |
| bdrv_set_aio_context_ignore(bs, ctx, &ignore); |
| g_slist_free(ignore); |
| |
| return 0; |
| } |
| |
| int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx, |
| Error **errp) |
| { |
| return bdrv_child_try_set_aio_context(bs, ctx, NULL, errp); |
| } |
| |
| void bdrv_add_aio_context_notifier(BlockDriverState *bs, |
| void (*attached_aio_context)(AioContext *new_context, void *opaque), |
| void (*detach_aio_context)(void *opaque), void *opaque) |
| { |
| BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1); |
| *ban = (BdrvAioNotifier){ |
| .attached_aio_context = attached_aio_context, |
| .detach_aio_context = detach_aio_context, |
| .opaque = opaque |
| }; |
| |
| QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list); |
| } |
| |
| void bdrv_remove_aio_context_notifier(BlockDriverState *bs, |
| void (*attached_aio_context)(AioContext *, |
| void *), |
| void (*detach_aio_context)(void *), |
| void *opaque) |
| { |
| BdrvAioNotifier *ban, *ban_next; |
| |
| QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { |
| if (ban->attached_aio_context == attached_aio_context && |
| ban->detach_aio_context == detach_aio_context && |
| ban->opaque == opaque && |
| ban->deleted == false) |
| { |
| if (bs->walking_aio_notifiers) { |
| ban->deleted = true; |
| } else { |
| bdrv_do_remove_aio_context_notifier(ban); |
| } |
| return; |
| } |
| } |
| |
| abort(); |
| } |
| |
| int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts, |
| BlockDriverAmendStatusCB *status_cb, void *cb_opaque, |
| bool force, |
| Error **errp) |
| { |
| if (!bs->drv) { |
| error_setg(errp, "Node is ejected"); |
| return -ENOMEDIUM; |
| } |
| if (!bs->drv->bdrv_amend_options) { |
| error_setg(errp, "Block driver '%s' does not support option amendment", |
| bs->drv->format_name); |
| return -ENOTSUP; |
| } |
| return bs->drv->bdrv_amend_options(bs, opts, status_cb, |
| cb_opaque, force, errp); |
| } |
| |
| /* |
| * This function checks whether the given @to_replace is allowed to be |
| * replaced by a node that always shows the same data as @bs. This is |
| * used for example to verify whether the mirror job can replace |
| * @to_replace by the target mirrored from @bs. |
| * To be replaceable, @bs and @to_replace may either be guaranteed to |
| * always show the same data (because they are only connected through |
| * filters), or some driver may allow replacing one of its children |
| * because it can guarantee that this child's data is not visible at |
| * all (for example, for dissenting quorum children that have no other |
| * parents). |
| */ |
| bool bdrv_recurse_can_replace(BlockDriverState *bs, |
| BlockDriverState *to_replace) |
| { |
| if (!bs || !bs->drv) { |
| return false; |
| } |
| |
| if (bs == to_replace) { |
| return true; |
| } |
| |
| /* See what the driver can do */ |
| if (bs->drv->bdrv_recurse_can_replace) { |
| return bs->drv->bdrv_recurse_can_replace(bs, to_replace); |
| } |
| |
| /* For filters without an own implementation, we can recurse on our own */ |
| if (bs->drv->is_filter) { |
| BdrvChild *child = bs->file ?: bs->backing; |
| return bdrv_recurse_can_replace(child->bs, to_replace); |
| } |
| |
| /* Safe default */ |
| return false; |
| } |
| |
| /* |
| * Check whether the given @node_name can be replaced by a node that |
| * has the same data as @parent_bs. If so, return @node_name's BDS; |
| * NULL otherwise. |
| * |
| * @node_name must be a (recursive) *child of @parent_bs (or this |
| * function will return NULL). |
| * |
| * The result (whether the node can be replaced or not) is only valid |
| * for as long as no graph or permission changes occur. |
| */ |
| BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs, |
| const char *node_name, Error **errp) |
| { |
| BlockDriverState *to_replace_bs = bdrv_find_node(node_name); |
| AioContext *aio_context; |
| |
| if (!to_replace_bs) { |
| error_setg(errp, "Node name '%s' not found", node_name); |
| return NULL; |
| } |
| |
| aio_context = bdrv_get_aio_context(to_replace_bs); |
| aio_context_acquire(aio_context); |
| |
| if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) { |
| to_replace_bs = NULL; |
| goto out; |
| } |
| |
| /* We don't want arbitrary node of the BDS chain to be replaced only the top |
| * most non filter in order to prevent data corruption. |
| * Another benefit is that this tests exclude backing files which are |
| * blocked by the backing blockers. |
| */ |
| if (!bdrv_recurse_can_replace(parent_bs, to_replace_bs)) { |
| error_setg(errp, "Cannot replace '%s' by a node mirrored from '%s', " |
| "because it cannot be guaranteed that doing so would not " |
| "lead to an abrupt change of visible data", |
| node_name, parent_bs->node_name); |
| to_replace_bs = NULL; |
| goto out; |
| } |
| |
| out: |
| aio_context_release(aio_context); |
| return to_replace_bs; |
| } |
| |
| /** |
| * Iterates through the list of runtime option keys that are said to |
| * be "strong" for a BDS. An option is called "strong" if it changes |
| * a BDS's data. For example, the null block driver's "size" and |
| * "read-zeroes" options are strong, but its "latency-ns" option is |
| * not. |
| * |
| * If a key returned by this function ends with a dot, all options |
| * starting with that prefix are strong. |
| */ |
| static const char *const *strong_options(BlockDriverState *bs, |
| const char *const *curopt) |
| { |
| static const char *const global_options[] = { |
| "driver", "filename", NULL |
| }; |
| |
| if (!curopt) { |
| return &global_options[0]; |
| } |
| |
| curopt++; |
| if (curopt == &global_options[ARRAY_SIZE(global_options) - 1] && bs->drv) { |
| curopt = bs->drv->strong_runtime_opts; |
| } |
| |
| return (curopt && *curopt) ? curopt : NULL; |
| } |
| |
| /** |
| * Copies all strong runtime options from bs->options to the given |
| * QDict. The set of strong option keys is determined by invoking |
| * strong_options(). |
| * |
| * Returns true iff any strong option was present in bs->options (and |
| * thus copied to the target QDict) with the exception of "filename" |
| * and "driver". The caller is expected to use this value to decide |
| * whether the existence of strong options prevents the generation of |
| * a plain filename. |
| */ |
| static bool append_strong_runtime_options(QDict *d, BlockDriverState *bs) |
| { |
| bool found_any = false; |
| const char *const *option_name = NULL; |
| |
| if (!bs->drv) { |
| return false; |
| } |
| |
| while ((option_name = strong_options(bs, option_name))) { |
| bool option_given = false; |
| |
| assert(strlen(*option_name) > 0); |
| if ((*option_name)[strlen(*option_name) - 1] != '.') { |
| QObject *entry = qdict_get(bs->options, *option_name); |
| if (!entry) { |
| continue; |
| } |
| |
| qdict_put_obj(d, *option_name, qobject_ref(entry)); |
| option_given = true; |
| } else { |
| const QDictEntry *entry; |
| for (entry = qdict_first(bs->options); entry; |
| entry = qdict_next(bs->options, entry)) |
| { |
| if (strstart(qdict_entry_key(entry), *option_name, NULL)) { |
| qdict_put_obj(d, qdict_entry_key(entry), |
| qobject_ref(qdict_entry_value(entry))); |
| option_given = true; |
| } |
| } |
| } |
| |
| /* While "driver" and "filename" need to be included in a JSON filename, |
| * their existence does not prohibit generation of a plain filename. */ |
| if (!found_any && option_given && |
| strcmp(*option_name, "driver") && strcmp(*option_name, "filename")) |
| { |
| found_any = true; |
| } |
| } |
| |
| if (!qdict_haskey(d, "driver")) { |
| /* Drivers created with bdrv_new_open_driver() may not have a |
| * @driver option. Add it here. */ |
| qdict_put_str(d, "driver", bs->drv->format_name); |
| } |
| |
| return found_any; |
| } |
| |
| /* Note: This function may return false positives; it may return true |
| * even if opening the backing file specified by bs's image header |
| * would result in exactly bs->backing. */ |
| static bool bdrv_backing_overridden(BlockDriverState *bs) |
| { |
| if (bs->backing) { |
| return strcmp(bs->auto_backing_file, |
| bs->backing->bs->filename); |
| } else { |
| /* No backing BDS, so if the image header reports any backing |
| * file, it must have been suppressed */ |
| return bs->auto_backing_file[0] != '\0'; |
| } |
| } |
| |
| /* Updates the following BDS fields: |
| * - exact_filename: A filename which may be used for opening a block device |
| * which (mostly) equals the given BDS (even without any |
| * other options; so reading and writing must return the same |
| * results, but caching etc. may be different) |
| * - full_open_options: Options which, when given when opening a block device |
| * (without a filename), result in a BDS (mostly) |
| * equalling the given one |
| * - filename: If exact_filename is set, it is copied here. Otherwise, |
| * full_open_options is converted to a JSON object, prefixed with |
| * "json:" (for use through the JSON pseudo protocol) and put here. |
| */ |
| void bdrv_refresh_filename(BlockDriverState *bs) |
| { |
| BlockDriver *drv = bs->drv; |
| BdrvChild *child; |
| QDict *opts; |
| bool backing_overridden; |
| bool generate_json_filename; /* Whether our default implementation should |
| fill exact_filename (false) or not (true) */ |
| |
| if (!drv) { |
| return; |
| } |
| |
| /* This BDS's file name may depend on any of its children's file names, so |
| * refresh those first */ |
| QLIST_FOREACH(child, &bs->children, next) { |
| bdrv_refresh_filename(child->bs); |
| } |
| |
| if (bs->implicit) { |
| /* For implicit nodes, just copy everything from the single child */ |
| child = QLIST_FIRST(&bs->children); |
| assert(QLIST_NEXT(child, next) == NULL); |
| |
| pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), |
| child->bs->exact_filename); |
| pstrcpy(bs->filename, sizeof(bs->filename), child->bs->filename); |
| |
| qobject_unref(bs->full_open_options); |
| bs->full_open_options = qobject_ref(child->bs->full_open_options); |
| |
| return; |
| } |
| |
| backing_overridden = bdrv_backing_overridden(bs); |
| |
| if (bs->open_flags & BDRV_O_NO_IO) { |
| /* Without I/O, the backing file does not change anything. |
| * Therefore, in such a case (primarily qemu-img), we can |
| * pretend the backing file has not been overridden even if |
| * it technically has been. */ |
| backing_overridden = false; |
| } |
| |
| /* Gather the options QDict */ |
| opts = qdict_new(); |
| generate_json_filename = append_strong_runtime_options(opts, bs); |
| generate_json_filename |= backing_overridden; |
| |
| if (drv->bdrv_gather_child_options) { |
| /* Some block drivers may not want to present all of their children's |
| * options, or name them differently from BdrvChild.name */ |
| drv->bdrv_gather_child_options(bs, opts, backing_overridden); |
| } else { |
| QLIST_FOREACH(child, &bs->children, next) { |
| if (child == bs->backing && !backing_overridden) { |
| /* We can skip the backing BDS if it has not been overridden */ |
| continue; |
| } |
| |
| qdict_put(opts, child->name, |
| qobject_ref(child->bs->full_open_options)); |
| } |
| |
| if (backing_overridden && !bs->backing) { |
| /* Force no backing file */ |
| qdict_put_null(opts, "backing"); |
| } |
| } |
| |
| qobject_unref(bs->full_open_options); |
| bs->full_open_options = opts; |
| |
| if (drv->bdrv_refresh_filename) { |
| /* Obsolete information is of no use here, so drop the old file name |
| * information before refreshing it */ |
| bs->exact_filename[0] = '\0'; |
| |
| drv->bdrv_refresh_filename(bs); |
| } else if (bs->file) { |
| /* Try to reconstruct valid information from the underlying file */ |
| |
| bs->exact_filename[0] = '\0'; |
| |
| /* |
| * We can use the underlying file's filename if: |
| * - it has a filename, |
| * - the file is a protocol BDS, and |
| * - opening that file (as this BDS's format) will automatically create |
| * the BDS tree we have right now, that is: |
| * - the user did not significantly change this BDS's behavior with |
| * some explicit (strong) options |
| * - no non-file child of this BDS has been overridden by the user |
| * Both of these conditions are represented by generate_json_filename. |
| */ |
| if (bs->file->bs->exact_filename[0] && |
| bs->file->bs->drv->bdrv_file_open && |
| !generate_json_filename) |
| { |
| strcpy(bs->exact_filename, bs->file->bs->exact_filename); |
| } |
| } |
| |
| if (bs->exact_filename[0]) { |
| pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename); |
| } else { |
| QString *json = qobject_to_json(QOBJECT(bs->full_open_options)); |
| if (snprintf(bs->filename, sizeof(bs->filename), "json:%s", |
| qstring_get_str(json)) >= sizeof(bs->filename)) { |
| /* Give user a hint if we truncated things. */ |
| strcpy(bs->filename + sizeof(bs->filename) - 4, "..."); |
| } |
| qobject_unref(json); |
| } |
| } |
| |
| char *bdrv_dirname(BlockDriverState *bs, Error **errp) |
| { |
| BlockDriver *drv = bs->drv; |
| |
| if (!drv) { |
| error_setg(errp, "Node '%s' is ejected", bs->node_name); |
| return NULL; |
| } |
| |
| if (drv->bdrv_dirname) { |
| return drv->bdrv_dirname(bs, errp); |
| } |
| |
| if (bs->file) { |
| return bdrv_dirname(bs->file->bs, errp); |
| } |
| |
| bdrv_refresh_filename(bs); |
| if (bs->exact_filename[0] != '\0') { |
| return path_combine(bs->exact_filename, ""); |
| } |
| |
| error_setg(errp, "Cannot generate a base directory for %s nodes", |
| drv->format_name); |
| return NULL; |
| } |
| |
| /* |
| * Hot add/remove a BDS's child. So the user can take a child offline when |
| * it is broken and take a new child online |
| */ |
| void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, |
| Error **errp) |
| { |
| |
| if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) { |
| error_setg(errp, "The node %s does not support adding a child", |
| bdrv_get_device_or_node_name(parent_bs)); |
| return; |
| } |
| |
| if (!QLIST_EMPTY(&child_bs->parents)) { |
| error_setg(errp, "The node %s already has a parent", |
| child_bs->node_name); |
| return; |
| } |
| |
| parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp); |
| } |
| |
| void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp) |
| { |
| BdrvChild *tmp; |
| |
| if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) { |
| error_setg(errp, "The node %s does not support removing a child", |
| bdrv_get_device_or_node_name(parent_bs)); |
| return; |
| } |
| |
| QLIST_FOREACH(tmp, &parent_bs->children, next) { |
| if (tmp == child) { |
| break; |
| } |
| } |
| |
| if (!tmp) { |
| error_setg(errp, "The node %s does not have a child named %s", |
| bdrv_get_device_or_node_name(parent_bs), |
| bdrv_get_device_or_node_name(child->bs)); |
| return; |
| } |
| |
| parent_bs->drv->bdrv_del_child(parent_bs, child, errp); |
| } |
| |
| int bdrv_make_empty(BdrvChild *c, Error **errp) |
| { |
| BlockDriver *drv = c->bs->drv; |
| int ret; |
| |
| assert(c->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)); |
| |
| if (!drv->bdrv_make_empty) { |
| error_setg(errp, "%s does not support emptying nodes", |
| drv->format_name); |
| return -ENOTSUP; |
| } |
| |
| ret = drv->bdrv_make_empty(c->bs); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Failed to empty %s", |
| c->bs->filename); |
| return ret; |
| } |
| |
| return 0; |
| } |