| /* |
| * 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. |
| */ |
| #ifndef BLOCK_INT_COMMON_H |
| #define BLOCK_INT_COMMON_H |
| |
| #include "block/accounting.h" |
| #include "block/block.h" |
| #include "block/aio-wait.h" |
| #include "qemu/queue.h" |
| #include "qemu/coroutine.h" |
| #include "qemu/stats64.h" |
| #include "qemu/timer.h" |
| #include "qemu/hbitmap.h" |
| #include "block/snapshot.h" |
| #include "qemu/throttle.h" |
| #include "qemu/rcu.h" |
| |
| #define BLOCK_FLAG_LAZY_REFCOUNTS 8 |
| |
| #define BLOCK_OPT_SIZE "size" |
| #define BLOCK_OPT_ENCRYPT "encryption" |
| #define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format" |
| #define BLOCK_OPT_COMPAT6 "compat6" |
| #define BLOCK_OPT_HWVERSION "hwversion" |
| #define BLOCK_OPT_BACKING_FILE "backing_file" |
| #define BLOCK_OPT_BACKING_FMT "backing_fmt" |
| #define BLOCK_OPT_CLUSTER_SIZE "cluster_size" |
| #define BLOCK_OPT_TABLE_SIZE "table_size" |
| #define BLOCK_OPT_PREALLOC "preallocation" |
| #define BLOCK_OPT_SUBFMT "subformat" |
| #define BLOCK_OPT_COMPAT_LEVEL "compat" |
| #define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts" |
| #define BLOCK_OPT_ADAPTER_TYPE "adapter_type" |
| #define BLOCK_OPT_REDUNDANCY "redundancy" |
| #define BLOCK_OPT_NOCOW "nocow" |
| #define BLOCK_OPT_EXTENT_SIZE_HINT "extent_size_hint" |
| #define BLOCK_OPT_OBJECT_SIZE "object_size" |
| #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits" |
| #define BLOCK_OPT_DATA_FILE "data_file" |
| #define BLOCK_OPT_DATA_FILE_RAW "data_file_raw" |
| #define BLOCK_OPT_COMPRESSION_TYPE "compression_type" |
| #define BLOCK_OPT_EXTL2 "extended_l2" |
| |
| #define BLOCK_PROBE_BUF_SIZE 512 |
| |
| enum BdrvTrackedRequestType { |
| BDRV_TRACKED_READ, |
| BDRV_TRACKED_WRITE, |
| BDRV_TRACKED_DISCARD, |
| BDRV_TRACKED_TRUNCATE, |
| }; |
| |
| /* |
| * That is not quite good that BdrvTrackedRequest structure is public, |
| * as block/io.c is very careful about incoming offset/bytes being |
| * correct. Be sure to assert bdrv_check_request() succeeded after any |
| * modification of BdrvTrackedRequest object out of block/io.c |
| */ |
| typedef struct BdrvTrackedRequest { |
| BlockDriverState *bs; |
| int64_t offset; |
| int64_t bytes; |
| enum BdrvTrackedRequestType type; |
| |
| bool serialising; |
| int64_t overlap_offset; |
| int64_t overlap_bytes; |
| |
| QLIST_ENTRY(BdrvTrackedRequest) list; |
| Coroutine *co; /* owner, used for deadlock detection */ |
| CoQueue wait_queue; /* coroutines blocked on this request */ |
| |
| struct BdrvTrackedRequest *waiting_for; |
| } BdrvTrackedRequest; |
| |
| |
| struct BlockDriver { |
| /* |
| * These fields are initialized when this object is created, |
| * and are never changed afterwards. |
| */ |
| |
| const char *format_name; |
| int instance_size; |
| |
| /* |
| * Set to true if the BlockDriver is a block filter. Block filters pass |
| * certain callbacks that refer to data (see block.c) to their bs->file |
| * or bs->backing (whichever one exists) if the driver doesn't implement |
| * them. Drivers that do not wish to forward must implement them and return |
| * -ENOTSUP. |
| * Note that filters are not allowed to modify data. |
| * |
| * Filters generally cannot have more than a single filtered child, |
| * because the data they present must at all times be the same as |
| * that on their filtered child. That would be impossible to |
| * achieve for multiple filtered children. |
| * (And this filtered child must then be bs->file or bs->backing.) |
| */ |
| bool is_filter; |
| /* |
| * Set to true if the BlockDriver is a format driver. Format nodes |
| * generally do not expect their children to be other format nodes |
| * (except for backing files), and so format probing is disabled |
| * on those children. |
| */ |
| bool is_format; |
| |
| /* |
| * Drivers not implementing bdrv_parse_filename nor bdrv_open should have |
| * this field set to true, except ones that are defined only by their |
| * child's bs. |
| * An example of the last type will be the quorum block driver. |
| */ |
| bool bdrv_needs_filename; |
| |
| /* |
| * Set if a driver can support backing files. This also implies the |
| * following semantics: |
| * |
| * - Return status 0 of .bdrv_co_block_status means that corresponding |
| * blocks are not allocated in this layer of backing-chain |
| * - For such (unallocated) blocks, read will: |
| * - fill buffer with zeros if there is no backing file |
| * - read from the backing file otherwise, where the block layer |
| * takes care of reading zeros beyond EOF if backing file is short |
| */ |
| bool supports_backing; |
| |
| bool has_variable_length; |
| |
| /* |
| * Drivers setting this field must be able to work with just a plain |
| * filename with '<protocol_name>:' as a prefix, and no other options. |
| * Options may be extracted from the filename by implementing |
| * bdrv_parse_filename. |
| */ |
| const char *protocol_name; |
| |
| /* List of options for creating images, terminated by name == NULL */ |
| QemuOptsList *create_opts; |
| |
| /* List of options for image amend */ |
| QemuOptsList *amend_opts; |
| |
| /* |
| * If this driver supports reopening images this contains a |
| * NULL-terminated list of the runtime options that can be |
| * modified. If an option in this list is unspecified during |
| * reopen then it _must_ be reset to its default value or return |
| * an error. |
| */ |
| const char *const *mutable_opts; |
| |
| /* |
| * Pointer to a NULL-terminated array of names of strong options |
| * that can be specified for bdrv_open(). A strong option is one |
| * that changes the data of a BDS. |
| * If this pointer is NULL, the array is considered empty. |
| * "filename" and "driver" are always considered strong. |
| */ |
| const char *const *strong_runtime_opts; |
| |
| |
| /* |
| * Global state (GS) API. These functions run under the BQL. |
| * |
| * See include/block/block-global-state.h for more information about |
| * the GS API. |
| */ |
| |
| /* |
| * This function is invoked under BQL before .bdrv_co_amend() |
| * (which in contrast does not necessarily run under the BQL) |
| * to allow driver-specific initialization code that requires |
| * the BQL, like setting up specific permission flags. |
| */ |
| int (*bdrv_amend_pre_run)(BlockDriverState *bs, Error **errp); |
| /* |
| * This function is invoked under BQL after .bdrv_co_amend() |
| * to allow cleaning up what was done in .bdrv_amend_pre_run(). |
| */ |
| void (*bdrv_amend_clean)(BlockDriverState *bs); |
| |
| /* |
| * Return true if @to_replace can be replaced by a BDS with the |
| * same data as @bs without it affecting @bs's behavior (that is, |
| * without it being visible to @bs's parents). |
| */ |
| bool (*bdrv_recurse_can_replace)(BlockDriverState *bs, |
| BlockDriverState *to_replace); |
| |
| int (*bdrv_probe_device)(const char *filename); |
| |
| /* |
| * Any driver implementing this callback is expected to be able to handle |
| * NULL file names in its .bdrv_open() implementation. |
| */ |
| void (*bdrv_parse_filename)(const char *filename, QDict *options, |
| Error **errp); |
| |
| /* For handling image reopen for split or non-split files. */ |
| int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state, |
| BlockReopenQueue *queue, Error **errp); |
| void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state); |
| void (*bdrv_reopen_commit_post)(BDRVReopenState *reopen_state); |
| void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state); |
| void (*bdrv_join_options)(QDict *options, QDict *old_options); |
| |
| int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags, |
| Error **errp); |
| |
| /* Protocol drivers should implement this instead of bdrv_open */ |
| int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags, |
| Error **errp); |
| void (*bdrv_close)(BlockDriverState *bs); |
| |
| int coroutine_fn (*bdrv_co_create)(BlockdevCreateOptions *opts, |
| Error **errp); |
| int coroutine_fn (*bdrv_co_create_opts)(BlockDriver *drv, |
| const char *filename, |
| QemuOpts *opts, |
| Error **errp); |
| |
| int (*bdrv_amend_options)(BlockDriverState *bs, |
| QemuOpts *opts, |
| BlockDriverAmendStatusCB *status_cb, |
| void *cb_opaque, |
| bool force, |
| Error **errp); |
| |
| int (*bdrv_make_empty)(BlockDriverState *bs); |
| |
| /* |
| * Refreshes the bs->exact_filename field. If that is impossible, |
| * bs->exact_filename has to be left empty. |
| */ |
| void (*bdrv_refresh_filename)(BlockDriverState *bs); |
| |
| /* |
| * Gathers the open options for all children into @target. |
| * A simple format driver (without backing file support) might |
| * implement this function like this: |
| * |
| * QINCREF(bs->file->bs->full_open_options); |
| * qdict_put(target, "file", bs->file->bs->full_open_options); |
| * |
| * If not specified, the generic implementation will simply put |
| * all children's options under their respective name. |
| * |
| * @backing_overridden is true when bs->backing seems not to be |
| * the child that would result from opening bs->backing_file. |
| * Therefore, if it is true, the backing child's options should be |
| * gathered; otherwise, there is no need since the backing child |
| * is the one implied by the image header. |
| * |
| * Note that ideally this function would not be needed. Every |
| * block driver which implements it is probably doing something |
| * shady regarding its runtime option structure. |
| */ |
| void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target, |
| bool backing_overridden); |
| |
| /* |
| * Returns an allocated string which is the directory name of this BDS: It |
| * will be used to make relative filenames absolute by prepending this |
| * function's return value to them. |
| */ |
| char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp); |
| |
| /* |
| * This informs the driver that we are no longer interested in the result |
| * of in-flight requests, so don't waste the time if possible. |
| * |
| * One example usage is to avoid waiting for an nbd target node reconnect |
| * timeout during job-cancel with force=true. |
| */ |
| void (*bdrv_cancel_in_flight)(BlockDriverState *bs); |
| |
| int (*bdrv_inactivate)(BlockDriverState *bs); |
| |
| int (*bdrv_snapshot_create)(BlockDriverState *bs, |
| QEMUSnapshotInfo *sn_info); |
| int (*bdrv_snapshot_goto)(BlockDriverState *bs, |
| const char *snapshot_id); |
| int (*bdrv_snapshot_delete)(BlockDriverState *bs, |
| const char *snapshot_id, |
| const char *name, |
| Error **errp); |
| int (*bdrv_snapshot_list)(BlockDriverState *bs, |
| QEMUSnapshotInfo **psn_info); |
| int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs, |
| const char *snapshot_id, |
| const char *name, |
| Error **errp); |
| |
| int (*bdrv_change_backing_file)(BlockDriverState *bs, |
| const char *backing_file, const char *backing_fmt); |
| |
| /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */ |
| int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event, |
| const char *tag); |
| int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs, |
| const char *tag); |
| int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag); |
| bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag); |
| |
| void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp); |
| |
| /* |
| * Returns 1 if newly created images are guaranteed to contain only |
| * zeros, 0 otherwise. |
| */ |
| int (*bdrv_has_zero_init)(BlockDriverState *bs); |
| |
| /* |
| * Remove fd handlers, timers, and other event loop callbacks so the event |
| * loop is no longer in use. Called with no in-flight requests and in |
| * depth-first traversal order with parents before child nodes. |
| */ |
| void (*bdrv_detach_aio_context)(BlockDriverState *bs); |
| |
| /* |
| * Add fd handlers, timers, and other event loop callbacks so I/O requests |
| * can be processed again. Called with no in-flight requests and in |
| * depth-first traversal order with child nodes before parent nodes. |
| */ |
| void (*bdrv_attach_aio_context)(BlockDriverState *bs, |
| AioContext *new_context); |
| |
| /** |
| * Try to get @bs's logical and physical block size. |
| * On success, store them in @bsz and return zero. |
| * On failure, return negative errno. |
| */ |
| int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz); |
| /** |
| * Try to get @bs's geometry (cyls, heads, sectors) |
| * On success, store them in @geo and return 0. |
| * On failure return -errno. |
| * Only drivers that want to override guest geometry implement this |
| * callback; see hd_geometry_guess(). |
| */ |
| int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); |
| |
| void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, |
| Error **errp); |
| void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, |
| Error **errp); |
| |
| /** |
| * Informs the block driver that a permission change is intended. The |
| * driver checks whether the change is permissible and may take other |
| * preparations for the change (e.g. get file system locks). This operation |
| * is always followed either by a call to either .bdrv_set_perm or |
| * .bdrv_abort_perm_update. |
| * |
| * Checks whether the requested set of cumulative permissions in @perm |
| * can be granted for accessing @bs and whether no other users are using |
| * permissions other than those given in @shared (both arguments take |
| * BLK_PERM_* bitmasks). |
| * |
| * If both conditions are met, 0 is returned. Otherwise, -errno is returned |
| * and errp is set to an error describing the conflict. |
| */ |
| int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm, |
| uint64_t shared, Error **errp); |
| |
| /** |
| * Called to inform the driver that the set of cumulative set of used |
| * permissions for @bs has changed to @perm, and the set of sharable |
| * permission to @shared. The driver can use this to propagate changes to |
| * its children (i.e. request permissions only if a parent actually needs |
| * them). |
| * |
| * This function is only invoked after bdrv_check_perm(), so block drivers |
| * may rely on preparations made in their .bdrv_check_perm implementation. |
| */ |
| void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared); |
| |
| /* |
| * Called to inform the driver 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 can be called even for nodes that never saw a |
| * bdrv_check_perm() call. It is a no-op then. |
| */ |
| void (*bdrv_abort_perm_update)(BlockDriverState *bs); |
| |
| /** |
| * Returns in @nperm and @nshared the permissions that the driver for @bs |
| * needs on its child @c, based on the cumulative permissions requested by |
| * the parents in @parent_perm and @parent_shared. |
| * |
| * If @c is NULL, return the permissions for attaching a new child for the |
| * given @child_class and @role. |
| * |
| * If @reopen_queue is non-NULL, don't return the currently needed |
| * permissions, but those that will be needed after applying the |
| * @reopen_queue. |
| */ |
| void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c, |
| BdrvChildRole role, |
| BlockReopenQueue *reopen_queue, |
| uint64_t parent_perm, uint64_t parent_shared, |
| uint64_t *nperm, uint64_t *nshared); |
| |
| /** |
| * Register/unregister a buffer for I/O. For example, when the driver is |
| * interested to know the memory areas that will later be used in iovs, so |
| * that it can do IOMMU mapping with VFIO etc., in order to get better |
| * performance. In the case of VFIO drivers, this callback is used to do |
| * DMA mapping for hot buffers. |
| */ |
| void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size); |
| void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); |
| |
| /* |
| * This field is modified only under the BQL, and is part of |
| * the global state. |
| */ |
| QLIST_ENTRY(BlockDriver) list; |
| |
| /* |
| * I/O API functions. These functions are thread-safe. |
| * |
| * See include/block/block-io.h for more information about |
| * the I/O API. |
| */ |
| |
| int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); |
| |
| int coroutine_fn (*bdrv_co_amend)(BlockDriverState *bs, |
| BlockdevAmendOptions *opts, |
| bool force, |
| Error **errp); |
| |
| /* aio */ |
| BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, |
| BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); |
| BlockAIOCB *(*bdrv_aio_pwritev)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, |
| BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); |
| BlockAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs, |
| BlockCompletionFunc *cb, void *opaque); |
| BlockAIOCB *(*bdrv_aio_pdiscard)(BlockDriverState *bs, |
| int64_t offset, int bytes, |
| BlockCompletionFunc *cb, void *opaque); |
| |
| int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, |
| int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); |
| |
| /** |
| * @offset: position in bytes to read at |
| * @bytes: number of bytes to read |
| * @qiov: the buffers to fill with read data |
| * @flags: currently unused, always 0 |
| * |
| * @offset and @bytes will be a multiple of 'request_alignment', |
| * but the length of individual @qiov elements does not have to |
| * be a multiple. |
| * |
| * @bytes will always equal the total size of @qiov, and will be |
| * no larger than 'max_transfer'. |
| * |
| * The buffer in @qiov may point directly to guest memory. |
| */ |
| int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, |
| BdrvRequestFlags flags); |
| |
| int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, |
| QEMUIOVector *qiov, size_t qiov_offset, |
| BdrvRequestFlags flags); |
| |
| int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, |
| int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, |
| int flags); |
| /** |
| * @offset: position in bytes to write at |
| * @bytes: number of bytes to write |
| * @qiov: the buffers containing data to write |
| * @flags: zero or more bits allowed by 'supported_write_flags' |
| * |
| * @offset and @bytes will be a multiple of 'request_alignment', |
| * but the length of individual @qiov elements does not have to |
| * be a multiple. |
| * |
| * @bytes will always equal the total size of @qiov, and will be |
| * no larger than 'max_transfer'. |
| * |
| * The buffer in @qiov may point directly to guest memory. |
| */ |
| int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, |
| BdrvRequestFlags flags); |
| int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, |
| BdrvRequestFlags flags); |
| |
| /* |
| * Efficiently zero a region of the disk image. Typically an image format |
| * would use a compact metadata representation to implement this. This |
| * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev() |
| * will be called instead. |
| */ |
| int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, BdrvRequestFlags flags); |
| int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes); |
| |
| /* |
| * Map [offset, offset + nbytes) range onto a child of @bs to copy from, |
| * and invoke bdrv_co_copy_range_from(child, ...), or invoke |
| * bdrv_co_copy_range_to() if @bs is the leaf child to copy data from. |
| * |
| * See the comment of bdrv_co_copy_range for the parameter and return value |
| * semantics. |
| */ |
| int coroutine_fn (*bdrv_co_copy_range_from)(BlockDriverState *bs, |
| BdrvChild *src, |
| int64_t offset, |
| BdrvChild *dst, |
| int64_t dst_offset, |
| int64_t bytes, |
| BdrvRequestFlags read_flags, |
| BdrvRequestFlags write_flags); |
| |
| /* |
| * Map [offset, offset + nbytes) range onto a child of bs to copy data to, |
| * and invoke bdrv_co_copy_range_to(child, src, ...), or perform the copy |
| * operation if @bs is the leaf and @src has the same BlockDriver. Return |
| * -ENOTSUP if @bs is the leaf but @src has a different BlockDriver. |
| * |
| * See the comment of bdrv_co_copy_range for the parameter and return value |
| * semantics. |
| */ |
| int coroutine_fn (*bdrv_co_copy_range_to)(BlockDriverState *bs, |
| BdrvChild *src, |
| int64_t src_offset, |
| BdrvChild *dst, |
| int64_t dst_offset, |
| int64_t bytes, |
| BdrvRequestFlags read_flags, |
| BdrvRequestFlags write_flags); |
| |
| /* |
| * Building block for bdrv_block_status[_above] and |
| * bdrv_is_allocated[_above]. The driver should answer only |
| * according to the current layer, and should only need to set |
| * BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID, |
| * and/or BDRV_BLOCK_RAW; if the current layer defers to a backing |
| * layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See |
| * block.h for the overall meaning of the bits. As a hint, the |
| * flag want_zero is true if the caller cares more about precise |
| * mappings (favor accurate _OFFSET_VALID/_ZERO) or false for |
| * overall allocation (favor larger *pnum, perhaps by reporting |
| * _DATA instead of _ZERO). The block layer guarantees input |
| * clamped to bdrv_getlength() and aligned to request_alignment, |
| * as well as non-NULL pnum, map, and file; in turn, the driver |
| * must return an error or set pnum to an aligned non-zero value. |
| * |
| * Note that @bytes is just a hint on how big of a region the |
| * caller wants to inspect. It is not a limit on *pnum. |
| * Implementations are free to return larger values of *pnum if |
| * doing so does not incur a performance penalty. |
| * |
| * block/io.c's bdrv_co_block_status() will utilize an unclamped |
| * *pnum value for the block-status cache on protocol nodes, prior |
| * to clamping *pnum for return to its caller. |
| */ |
| int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs, |
| bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, |
| int64_t *map, BlockDriverState **file); |
| |
| /* |
| * Invalidate any cached meta-data. |
| */ |
| void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs, |
| Error **errp); |
| |
| /* |
| * Flushes all data for all layers by calling bdrv_co_flush for underlying |
| * layers, if needed. This function is needed for deterministic |
| * synchronization of the flush finishing callback. |
| */ |
| int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); |
| |
| /* Delete a created file. */ |
| int coroutine_fn (*bdrv_co_delete_file)(BlockDriverState *bs, |
| Error **errp); |
| |
| /* |
| * Flushes all data that was already written to the OS all the way down to |
| * the disk (for example file-posix.c calls fsync()). |
| */ |
| int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); |
| |
| /* |
| * Flushes all internal caches to the OS. The data may still sit in a |
| * writeback cache of the host OS, but it will survive a crash of the qemu |
| * process. |
| */ |
| int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs); |
| |
| /* |
| * Truncate @bs to @offset bytes using the given @prealloc mode |
| * when growing. Modes other than PREALLOC_MODE_OFF should be |
| * rejected when shrinking @bs. |
| * |
| * If @exact is true, @bs must be resized to exactly @offset. |
| * Otherwise, it is sufficient for @bs (if it is a host block |
| * device and thus there is no way to resize it) to be at least |
| * @offset bytes in length. |
| * |
| * If @exact is true and this function fails but would succeed |
| * with @exact = false, it should return -ENOTSUP. |
| */ |
| int coroutine_fn (*bdrv_co_truncate)(BlockDriverState *bs, int64_t offset, |
| bool exact, PreallocMode prealloc, |
| BdrvRequestFlags flags, Error **errp); |
| int64_t (*bdrv_getlength)(BlockDriverState *bs); |
| int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); |
| BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, |
| Error **errp); |
| |
| int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov); |
| int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, |
| size_t qiov_offset); |
| |
| int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi); |
| |
| ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs, |
| Error **errp); |
| BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs); |
| |
| int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs, |
| QEMUIOVector *qiov, |
| int64_t pos); |
| int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs, |
| QEMUIOVector *qiov, |
| int64_t pos); |
| |
| /* removable device specific */ |
| bool (*bdrv_is_inserted)(BlockDriverState *bs); |
| void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag); |
| void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked); |
| |
| /* to control generic scsi devices */ |
| BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs, |
| unsigned long int req, void *buf, |
| BlockCompletionFunc *cb, void *opaque); |
| int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs, |
| unsigned long int req, void *buf); |
| |
| /* |
| * Returns 0 for completed check, -errno for internal errors. |
| * The check results are stored in result. |
| */ |
| int coroutine_fn (*bdrv_co_check)(BlockDriverState *bs, |
| BdrvCheckResult *result, |
| BdrvCheckMode fix); |
| |
| void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event); |
| |
| /* io queue for linux-aio */ |
| void (*bdrv_io_plug)(BlockDriverState *bs); |
| void (*bdrv_io_unplug)(BlockDriverState *bs); |
| |
| /** |
| * bdrv_co_drain_begin is called if implemented in the beginning of a |
| * drain operation to drain and stop any internal sources of requests in |
| * the driver. |
| * bdrv_co_drain_end is called if implemented at the end of the drain. |
| * |
| * They should be used by the driver to e.g. manage scheduled I/O |
| * requests, or toggle an internal state. After the end of the drain new |
| * requests will continue normally. |
| */ |
| void coroutine_fn (*bdrv_co_drain_begin)(BlockDriverState *bs); |
| void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs); |
| |
| bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs); |
| bool (*bdrv_co_can_store_new_dirty_bitmap)(BlockDriverState *bs, |
| const char *name, |
| uint32_t granularity, |
| Error **errp); |
| int (*bdrv_co_remove_persistent_dirty_bitmap)(BlockDriverState *bs, |
| const char *name, |
| Error **errp); |
| }; |
| |
| static inline bool block_driver_can_compress(BlockDriver *drv) |
| { |
| return drv->bdrv_co_pwritev_compressed || |
| drv->bdrv_co_pwritev_compressed_part; |
| } |
| |
| typedef struct BlockLimits { |
| /* |
| * Alignment requirement, in bytes, for offset/length of I/O |
| * requests. Must be a power of 2 less than INT_MAX; defaults to |
| * 1 for drivers with modern byte interfaces, and to 512 |
| * otherwise. |
| */ |
| uint32_t request_alignment; |
| |
| /* |
| * Maximum number of bytes that can be discarded at once. Must be multiple |
| * of pdiscard_alignment, but need not be power of 2. May be 0 if no |
| * inherent 64-bit limit. |
| */ |
| int64_t max_pdiscard; |
| |
| /* |
| * Optimal alignment for discard requests in bytes. A power of 2 |
| * is best but not mandatory. Must be a multiple of |
| * bl.request_alignment, and must be less than max_pdiscard if |
| * that is set. May be 0 if bl.request_alignment is good enough |
| */ |
| uint32_t pdiscard_alignment; |
| |
| /* |
| * Maximum number of bytes that can zeroized at once. Must be multiple of |
| * pwrite_zeroes_alignment. 0 means no limit. |
| */ |
| int64_t max_pwrite_zeroes; |
| |
| /* |
| * Optimal alignment for write zeroes requests in bytes. A power |
| * of 2 is best but not mandatory. Must be a multiple of |
| * bl.request_alignment, and must be less than max_pwrite_zeroes |
| * if that is set. May be 0 if bl.request_alignment is good |
| * enough |
| */ |
| uint32_t pwrite_zeroes_alignment; |
| |
| /* |
| * Optimal transfer length in bytes. A power of 2 is best but not |
| * mandatory. Must be a multiple of bl.request_alignment, or 0 if |
| * no preferred size |
| */ |
| uint32_t opt_transfer; |
| |
| /* |
| * Maximal transfer length in bytes. Need not be power of 2, but |
| * must be multiple of opt_transfer and bl.request_alignment, or 0 |
| * for no 32-bit limit. For now, anything larger than INT_MAX is |
| * clamped down. |
| */ |
| uint32_t max_transfer; |
| |
| /* |
| * Maximal hardware transfer length in bytes. Applies whenever |
| * transfers to the device bypass the kernel I/O scheduler, for |
| * example with SG_IO. If larger than max_transfer or if zero, |
| * blk_get_max_hw_transfer will fall back to max_transfer. |
| */ |
| uint64_t max_hw_transfer; |
| |
| /* |
| * Maximal number of scatter/gather elements allowed by the hardware. |
| * Applies whenever transfers to the device bypass the kernel I/O |
| * scheduler, for example with SG_IO. If larger than max_iov |
| * or if zero, blk_get_max_hw_iov will fall back to max_iov. |
| */ |
| int max_hw_iov; |
| |
| |
| /* memory alignment, in bytes so that no bounce buffer is needed */ |
| size_t min_mem_alignment; |
| |
| /* memory alignment, in bytes, for bounce buffer */ |
| size_t opt_mem_alignment; |
| |
| /* maximum number of iovec elements */ |
| int max_iov; |
| } BlockLimits; |
| |
| typedef struct BdrvOpBlocker BdrvOpBlocker; |
| |
| typedef struct BdrvAioNotifier { |
| void (*attached_aio_context)(AioContext *new_context, void *opaque); |
| void (*detach_aio_context)(void *opaque); |
| |
| void *opaque; |
| bool deleted; |
| |
| QLIST_ENTRY(BdrvAioNotifier) list; |
| } BdrvAioNotifier; |
| |
| struct BdrvChildClass { |
| /* |
| * If true, bdrv_replace_node() doesn't change the node this BdrvChild |
| * points to. |
| */ |
| bool stay_at_node; |
| |
| /* |
| * If true, the parent is a BlockDriverState and bdrv_next_all_states() |
| * will return it. This information is used for drain_all, where every node |
| * will be drained separately, so the drain only needs to be propagated to |
| * non-BDS parents. |
| */ |
| bool parent_is_bds; |
| |
| /* |
| * Global state (GS) API. These functions run under the BQL. |
| * |
| * See include/block/block-global-state.h for more information about |
| * the GS API. |
| */ |
| void (*inherit_options)(BdrvChildRole role, bool parent_is_format, |
| int *child_flags, QDict *child_options, |
| int parent_flags, QDict *parent_options); |
| void (*change_media)(BdrvChild *child, bool load); |
| |
| /* |
| * Returns a malloced string that describes the parent of the child for a |
| * human reader. This could be a node-name, BlockBackend name, qdev ID or |
| * QOM path of the device owning the BlockBackend, job type and ID etc. The |
| * caller is responsible for freeing the memory. |
| */ |
| char *(*get_parent_desc)(BdrvChild *child); |
| |
| /* |
| * Notifies the parent that the child has been activated/inactivated (e.g. |
| * when migration is completing) and it can start/stop requesting |
| * permissions and doing I/O on it. |
| */ |
| void (*activate)(BdrvChild *child, Error **errp); |
| int (*inactivate)(BdrvChild *child); |
| |
| void (*attach)(BdrvChild *child); |
| void (*detach)(BdrvChild *child); |
| |
| /* |
| * Notifies the parent that the filename of its child has changed (e.g. |
| * because the direct child was removed from the backing chain), so that it |
| * can update its reference. |
| */ |
| int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, |
| const char *filename, Error **errp); |
| |
| bool (*can_set_aio_ctx)(BdrvChild *child, AioContext *ctx, |
| GSList **ignore, Error **errp); |
| void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore); |
| |
| AioContext *(*get_parent_aio_context)(BdrvChild *child); |
| |
| /* |
| * I/O API functions. These functions are thread-safe. |
| * |
| * See include/block/block-io.h for more information about |
| * the I/O API. |
| */ |
| |
| void (*resize)(BdrvChild *child); |
| |
| /* |
| * Returns a name that is supposedly more useful for human users than the |
| * node name for identifying the node in question (in particular, a BB |
| * name), or NULL if the parent can't provide a better name. |
| */ |
| const char *(*get_name)(BdrvChild *child); |
| |
| /* |
| * If this pair of functions is implemented, the parent doesn't issue new |
| * requests after returning from .drained_begin() until .drained_end() is |
| * called. |
| * |
| * These functions must not change the graph (and therefore also must not |
| * call aio_poll(), which could change the graph indirectly). |
| * |
| * If drained_end() schedules background operations, it must atomically |
| * increment *drained_end_counter for each such operation and atomically |
| * decrement it once the operation has settled. |
| * |
| * Note that this can be nested. If drained_begin() was called twice, new |
| * I/O is allowed only after drained_end() was called twice, too. |
| */ |
| void (*drained_begin)(BdrvChild *child); |
| void (*drained_end)(BdrvChild *child, int *drained_end_counter); |
| |
| /* |
| * Returns whether the parent has pending requests for the child. This |
| * callback is polled after .drained_begin() has been called until all |
| * activity on the child has stopped. |
| */ |
| bool (*drained_poll)(BdrvChild *child); |
| }; |
| |
| extern const BdrvChildClass child_of_bds; |
| |
| struct BdrvChild { |
| BlockDriverState *bs; |
| char *name; |
| const BdrvChildClass *klass; |
| BdrvChildRole role; |
| void *opaque; |
| |
| /** |
| * Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask) |
| */ |
| uint64_t perm; |
| |
| /** |
| * Permissions that can still be granted to other users of @bs while this |
| * BdrvChild is still attached to it. (BLK_PERM_* bitmask) |
| */ |
| uint64_t shared_perm; |
| |
| /* |
| * This link is frozen: the child can neither be replaced nor |
| * detached from the parent. |
| */ |
| bool frozen; |
| |
| /* |
| * How many times the parent of this child has been drained |
| * (through klass->drained_*). |
| * Usually, this is equal to bs->quiesce_counter (potentially |
| * reduced by bdrv_drain_all_count). It may differ while the |
| * child is entering or leaving a drained section. |
| */ |
| int parent_quiesce_counter; |
| |
| QLIST_ENTRY(BdrvChild) next; |
| QLIST_ENTRY(BdrvChild) next_parent; |
| }; |
| |
| /* |
| * Allows bdrv_co_block_status() to cache one data region for a |
| * protocol node. |
| * |
| * @valid: Whether the cache is valid (should be accessed with atomic |
| * functions so this can be reset by RCU readers) |
| * @data_start: Offset where we know (or strongly assume) is data |
| * @data_end: Offset where the data region ends (which is not necessarily |
| * the start of a zeroed region) |
| */ |
| typedef struct BdrvBlockStatusCache { |
| struct rcu_head rcu; |
| |
| bool valid; |
| int64_t data_start; |
| int64_t data_end; |
| } BdrvBlockStatusCache; |
| |
| struct BlockDriverState { |
| /* |
| * Protected by big QEMU lock or read-only after opening. No special |
| * locking needed during I/O... |
| */ |
| int open_flags; /* flags used to open the file, re-used for re-open */ |
| bool encrypted; /* if true, the media is encrypted */ |
| bool sg; /* if true, the device is a /dev/sg* */ |
| bool probed; /* if true, format was probed rather than specified */ |
| bool force_share; /* if true, always allow all shared permissions */ |
| bool implicit; /* if true, this filter node was automatically inserted */ |
| |
| BlockDriver *drv; /* NULL means no media */ |
| void *opaque; |
| |
| AioContext *aio_context; /* event loop used for fd handlers, timers, etc */ |
| /* |
| * long-running tasks intended to always use the same AioContext as this |
| * BDS may register themselves in this list to be notified of changes |
| * regarding this BDS's context |
| */ |
| QLIST_HEAD(, BdrvAioNotifier) aio_notifiers; |
| bool walking_aio_notifiers; /* to make removal during iteration safe */ |
| |
| char filename[PATH_MAX]; |
| /* |
| * If not empty, this image is a diff in relation to backing_file. |
| * Note that this is the name given in the image header and |
| * therefore may or may not be equal to .backing->bs->filename. |
| * If this field contains a relative path, it is to be resolved |
| * relatively to the overlay's location. |
| */ |
| char backing_file[PATH_MAX]; |
| /* |
| * The backing filename indicated by the image header. Contrary |
| * to backing_file, if we ever open this file, auto_backing_file |
| * is replaced by the resulting BDS's filename (i.e. after a |
| * bdrv_refresh_filename() run). |
| */ |
| char auto_backing_file[PATH_MAX]; |
| char backing_format[16]; /* if non-zero and backing_file exists */ |
| |
| QDict *full_open_options; |
| char exact_filename[PATH_MAX]; |
| |
| BdrvChild *backing; |
| BdrvChild *file; |
| |
| /* I/O Limits */ |
| BlockLimits bl; |
| |
| /* |
| * Flags honored during pread |
| */ |
| unsigned int supported_read_flags; |
| /* |
| * Flags honored during pwrite (so far: BDRV_REQ_FUA, |
| * BDRV_REQ_WRITE_UNCHANGED). |
| * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those |
| * writes will be issued as normal writes without the flag set. |
| * This is important to note for drivers that do not explicitly |
| * request a WRITE permission for their children and instead take |
| * the same permissions as their parent did (this is commonly what |
| * block filters do). Such drivers have to be aware that the |
| * parent may have taken a WRITE_UNCHANGED permission only and is |
| * issuing such requests. Drivers either must make sure that |
| * these requests do not result in plain WRITE accesses (usually |
| * by supporting BDRV_REQ_WRITE_UNCHANGED, and then forwarding |
| * every incoming write request as-is, including potentially that |
| * flag), or they have to explicitly take the WRITE permission for |
| * their children. |
| */ |
| unsigned int supported_write_flags; |
| /* |
| * Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA, |
| * BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED) |
| */ |
| unsigned int supported_zero_flags; |
| /* |
| * Flags honoured during truncate (so far: BDRV_REQ_ZERO_WRITE). |
| * |
| * If BDRV_REQ_ZERO_WRITE is given, the truncate operation must make sure |
| * that any added space reads as all zeros. If this can't be guaranteed, |
| * the operation must fail. |
| */ |
| unsigned int supported_truncate_flags; |
| |
| /* the following member gives a name to every node on the bs graph. */ |
| char node_name[32]; |
| /* element of the list of named nodes building the graph */ |
| QTAILQ_ENTRY(BlockDriverState) node_list; |
| /* element of the list of all BlockDriverStates (all_bdrv_states) */ |
| QTAILQ_ENTRY(BlockDriverState) bs_list; |
| /* element of the list of monitor-owned BDS */ |
| QTAILQ_ENTRY(BlockDriverState) monitor_list; |
| int refcnt; |
| |
| /* operation blockers. Protected by BQL. */ |
| QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; |
| |
| /* |
| * The node that this node inherited default options from (and a reopen on |
| * which can affect this node by changing these defaults). This is always a |
| * parent node of this node. |
| */ |
| BlockDriverState *inherits_from; |
| QLIST_HEAD(, BdrvChild) children; |
| QLIST_HEAD(, BdrvChild) parents; |
| |
| QDict *options; |
| QDict *explicit_options; |
| BlockdevDetectZeroesOptions detect_zeroes; |
| |
| /* The error object in use for blocking operations on backing_hd */ |
| Error *backing_blocker; |
| |
| /* Protected by AioContext lock */ |
| |
| /* |
| * If we are reading a disk image, give its size in sectors. |
| * Generally read-only; it is written to by load_snapshot and |
| * save_snaphost, but the block layer is quiescent during those. |
| */ |
| int64_t total_sectors; |
| |
| /* threshold limit for writes, in bytes. "High water mark". */ |
| uint64_t write_threshold_offset; |
| |
| /* |
| * Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. |
| * Reading from the list can be done with either the BQL or the |
| * dirty_bitmap_mutex. Modifying a bitmap only requires |
| * dirty_bitmap_mutex. |
| */ |
| QemuMutex dirty_bitmap_mutex; |
| QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; |
| |
| /* Offset after the highest byte written to */ |
| Stat64 wr_highest_offset; |
| |
| /* |
| * If true, copy read backing sectors into image. Can be >1 if more |
| * than one client has requested copy-on-read. Accessed with atomic |
| * ops. |
| */ |
| int copy_on_read; |
| |
| /* |
| * number of in-flight requests; overall and serialising. |
| * Accessed with atomic ops. |
| */ |
| unsigned int in_flight; |
| unsigned int serialising_in_flight; |
| |
| /* |
| * counter for nested bdrv_io_plug. |
| * Accessed with atomic ops. |
| */ |
| unsigned io_plugged; |
| |
| /* do we need to tell the quest if we have a volatile write cache? */ |
| int enable_write_cache; |
| |
| /* Accessed with atomic ops. */ |
| int quiesce_counter; |
| int recursive_quiesce_counter; |
| |
| unsigned int write_gen; /* Current data generation */ |
| |
| /* Protected by reqs_lock. */ |
| CoMutex reqs_lock; |
| QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; |
| CoQueue flush_queue; /* Serializing flush queue */ |
| bool active_flush_req; /* Flush request in flight? */ |
| |
| /* Only read/written by whoever has set active_flush_req to true. */ |
| unsigned int flushed_gen; /* Flushed write generation */ |
| |
| /* BdrvChild links to this node may never be frozen */ |
| bool never_freeze; |
| |
| /* Lock for block-status cache RCU writers */ |
| CoMutex bsc_modify_lock; |
| /* Always non-NULL, but must only be dereferenced under an RCU read guard */ |
| BdrvBlockStatusCache *block_status_cache; |
| }; |
| |
| struct BlockBackendRootState { |
| int open_flags; |
| BlockdevDetectZeroesOptions detect_zeroes; |
| }; |
| |
| typedef enum BlockMirrorBackingMode { |
| /* |
| * Reuse the existing backing chain from the source for the target. |
| * - sync=full: Set backing BDS to NULL. |
| * - sync=top: Use source's backing BDS. |
| * - sync=none: Use source as the backing BDS. |
| */ |
| MIRROR_SOURCE_BACKING_CHAIN, |
| |
| /* Open the target's backing chain completely anew */ |
| MIRROR_OPEN_BACKING_CHAIN, |
| |
| /* Do not change the target's backing BDS after job completion */ |
| MIRROR_LEAVE_BACKING_CHAIN, |
| } BlockMirrorBackingMode; |
| |
| |
| /* |
| * Essential block drivers which must always be statically linked into qemu, and |
| * which therefore can be accessed without using bdrv_find_format() |
| */ |
| extern BlockDriver bdrv_file; |
| extern BlockDriver bdrv_raw; |
| extern BlockDriver bdrv_qcow2; |
| |
| extern unsigned int bdrv_drain_all_count; |
| extern QemuOptsList bdrv_create_opts_simple; |
| |
| /* |
| * Common functions that are neither I/O nor Global State. |
| * |
| * See include/block/block-commmon.h for more information about |
| * the Common API. |
| */ |
| |
| static inline BlockDriverState *child_bs(BdrvChild *child) |
| { |
| return child ? child->bs : NULL; |
| } |
| |
| int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp); |
| int get_tmp_filename(char *filename, int size); |
| void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, |
| QDict *options); |
| |
| |
| int bdrv_check_qiov_request(int64_t offset, int64_t bytes, |
| QEMUIOVector *qiov, size_t qiov_offset, |
| Error **errp); |
| |
| #ifdef _WIN32 |
| int is_windows_drive(const char *filename); |
| #endif |
| |
| #endif /* BLOCK_INT_COMMON_H */ |
