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qemu / qemu / 7f303adc4f0aaa71b196d9f983150f3ec3367b46 / . / block / sheepdog.c
blob: 21a4edf15befe3e673273c5814ccb21748455352 [file] [log] [blame]
/*
* Copyright (C) 2009-2010 Nippon Telegraph and Telephone Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu-common.h"
#include "qemu/uri.h"
#include "qemu/error-report.h"
#include "qemu/sockets.h"
#include "block/block_int.h"
#include "qemu/bitops.h"
#define SD_PROTO_VER 0x01
#define SD_DEFAULT_ADDR "localhost"
#define SD_DEFAULT_PORT 7000
#define SD_OP_CREATE_AND_WRITE_OBJ 0x01
#define SD_OP_READ_OBJ 0x02
#define SD_OP_WRITE_OBJ 0x03
/* 0x04 is used internally by Sheepdog */
#define SD_OP_DISCARD_OBJ 0x05
#define SD_OP_NEW_VDI 0x11
#define SD_OP_LOCK_VDI 0x12
#define SD_OP_RELEASE_VDI 0x13
#define SD_OP_GET_VDI_INFO 0x14
#define SD_OP_READ_VDIS 0x15
#define SD_OP_FLUSH_VDI 0x16
#define SD_OP_DEL_VDI 0x17
#define SD_FLAG_CMD_WRITE 0x01
#define SD_FLAG_CMD_COW 0x02
#define SD_FLAG_CMD_CACHE 0x04 /* Writeback mode for cache */
#define SD_FLAG_CMD_DIRECT 0x08 /* Don't use cache */
#define SD_RES_SUCCESS 0x00 /* Success */
#define SD_RES_UNKNOWN 0x01 /* Unknown error */
#define SD_RES_NO_OBJ 0x02 /* No object found */
#define SD_RES_EIO 0x03 /* I/O error */
#define SD_RES_VDI_EXIST 0x04 /* Vdi exists already */
#define SD_RES_INVALID_PARMS 0x05 /* Invalid parameters */
#define SD_RES_SYSTEM_ERROR 0x06 /* System error */
#define SD_RES_VDI_LOCKED 0x07 /* Vdi is locked */
#define SD_RES_NO_VDI 0x08 /* No vdi found */
#define SD_RES_NO_BASE_VDI 0x09 /* No base vdi found */
#define SD_RES_VDI_READ 0x0A /* Cannot read requested vdi */
#define SD_RES_VDI_WRITE 0x0B /* Cannot write requested vdi */
#define SD_RES_BASE_VDI_READ 0x0C /* Cannot read base vdi */
#define SD_RES_BASE_VDI_WRITE 0x0D /* Cannot write base vdi */
#define SD_RES_NO_TAG 0x0E /* Requested tag is not found */
#define SD_RES_STARTUP 0x0F /* Sheepdog is on starting up */
#define SD_RES_VDI_NOT_LOCKED 0x10 /* Vdi is not locked */
#define SD_RES_SHUTDOWN 0x11 /* Sheepdog is shutting down */
#define SD_RES_NO_MEM 0x12 /* Cannot allocate memory */
#define SD_RES_FULL_VDI 0x13 /* we already have the maximum vdis */
#define SD_RES_VER_MISMATCH 0x14 /* Protocol version mismatch */
#define SD_RES_NO_SPACE 0x15 /* Server has no room for new objects */
#define SD_RES_WAIT_FOR_FORMAT 0x16 /* Waiting for a format operation */
#define SD_RES_WAIT_FOR_JOIN 0x17 /* Waiting for other nodes joining */
#define SD_RES_JOIN_FAILED 0x18 /* Target node had failed to join sheepdog */
#define SD_RES_HALT 0x19 /* Sheepdog is stopped serving IO request */
#define SD_RES_READONLY 0x1A /* Object is read-only */
/*
* Object ID rules
*
* 0 - 19 (20 bits): data object space
* 20 - 31 (12 bits): reserved data object space
* 32 - 55 (24 bits): vdi object space
* 56 - 59 ( 4 bits): reserved vdi object space
* 60 - 63 ( 4 bits): object type identifier space
*/
#define VDI_SPACE_SHIFT 32
#define VDI_BIT (UINT64_C(1) << 63)
#define VMSTATE_BIT (UINT64_C(1) << 62)
#define MAX_DATA_OBJS (UINT64_C(1) << 20)
#define MAX_CHILDREN 1024
#define SD_MAX_VDI_LEN 256
#define SD_MAX_VDI_TAG_LEN 256
#define SD_NR_VDIS (1U << 24)
#define SD_DATA_OBJ_SIZE (UINT64_C(1) << 22)
#define SD_MAX_VDI_SIZE (SD_DATA_OBJ_SIZE * MAX_DATA_OBJS)
#define SD_INODE_SIZE (sizeof(SheepdogInode))
#define CURRENT_VDI_ID 0
typedef struct SheepdogReq {
uint8_t proto_ver;
uint8_t opcode;
uint16_t flags;
uint32_t epoch;
uint32_t id;
uint32_t data_length;
uint32_t opcode_specific[8];
} SheepdogReq;
typedef struct SheepdogRsp {
uint8_t proto_ver;
uint8_t opcode;
uint16_t flags;
uint32_t epoch;
uint32_t id;
uint32_t data_length;
uint32_t result;
uint32_t opcode_specific[7];
} SheepdogRsp;
typedef struct SheepdogObjReq {
uint8_t proto_ver;
uint8_t opcode;
uint16_t flags;
uint32_t epoch;
uint32_t id;
uint32_t data_length;
uint64_t oid;
uint64_t cow_oid;
uint32_t copies;
uint32_t rsvd;
uint64_t offset;
} SheepdogObjReq;
typedef struct SheepdogObjRsp {
uint8_t proto_ver;
uint8_t opcode;
uint16_t flags;
uint32_t epoch;
uint32_t id;
uint32_t data_length;
uint32_t result;
uint32_t copies;
uint32_t pad[6];
} SheepdogObjRsp;
typedef struct SheepdogVdiReq {
uint8_t proto_ver;
uint8_t opcode;
uint16_t flags;
uint32_t epoch;
uint32_t id;
uint32_t data_length;
uint64_t vdi_size;
uint32_t vdi_id;
uint32_t copies;
uint32_t snapid;
uint32_t pad[3];
} SheepdogVdiReq;
typedef struct SheepdogVdiRsp {
uint8_t proto_ver;
uint8_t opcode;
uint16_t flags;
uint32_t epoch;
uint32_t id;
uint32_t data_length;
uint32_t result;
uint32_t rsvd;
uint32_t vdi_id;
uint32_t pad[5];
} SheepdogVdiRsp;
typedef struct SheepdogInode {
char name[SD_MAX_VDI_LEN];
char tag[SD_MAX_VDI_TAG_LEN];
uint64_t ctime;
uint64_t snap_ctime;
uint64_t vm_clock_nsec;
uint64_t vdi_size;
uint64_t vm_state_size;
uint16_t copy_policy;
uint8_t nr_copies;
uint8_t block_size_shift;
uint32_t snap_id;
uint32_t vdi_id;
uint32_t parent_vdi_id;
uint32_t child_vdi_id[MAX_CHILDREN];
uint32_t data_vdi_id[MAX_DATA_OBJS];
} SheepdogInode;
/*
* 64 bit FNV-1a non-zero initial basis
*/
#define FNV1A_64_INIT ((uint64_t)0xcbf29ce484222325ULL)
/*
* 64 bit Fowler/Noll/Vo FNV-1a hash code
*/
static inline uint64_t fnv_64a_buf(void *buf, size_t len, uint64_t hval)
{
unsigned char *bp = buf;
unsigned char *be = bp + len;
while (bp < be) {
hval ^= (uint64_t) *bp++;
hval += (hval << 1) + (hval << 4) + (hval << 5) +
(hval << 7) + (hval << 8) + (hval << 40);
}
return hval;
}
static inline bool is_data_obj_writable(SheepdogInode *inode, unsigned int idx)
{
return inode->vdi_id == inode->data_vdi_id[idx];
}
static inline bool is_data_obj(uint64_t oid)
{
return !(VDI_BIT & oid);
}
static inline uint64_t data_oid_to_idx(uint64_t oid)
{
return oid & (MAX_DATA_OBJS - 1);
}
static inline uint64_t vid_to_vdi_oid(uint32_t vid)
{
return VDI_BIT | ((uint64_t)vid << VDI_SPACE_SHIFT);
}
static inline uint64_t vid_to_vmstate_oid(uint32_t vid, uint32_t idx)
{
return VMSTATE_BIT | ((uint64_t)vid << VDI_SPACE_SHIFT) | idx;
}
static inline uint64_t vid_to_data_oid(uint32_t vid, uint32_t idx)
{
return ((uint64_t)vid << VDI_SPACE_SHIFT) | idx;
}
static inline bool is_snapshot(struct SheepdogInode *inode)
{
return !!inode->snap_ctime;
}
#undef dprintf
#ifdef DEBUG_SDOG
#define dprintf(fmt, args...) \
do { \
fprintf(stdout, "%s %d: " fmt, __func__, __LINE__, ##args); \
} while (0)
#else
#define dprintf(fmt, args...)
#endif
typedef struct SheepdogAIOCB SheepdogAIOCB;
typedef struct AIOReq {
SheepdogAIOCB *aiocb;
unsigned int iov_offset;
uint64_t oid;
uint64_t base_oid;
uint64_t offset;
unsigned int data_len;
uint8_t flags;
uint32_t id;
QLIST_ENTRY(AIOReq) aio_siblings;
} AIOReq;
enum AIOCBState {
AIOCB_WRITE_UDATA,
AIOCB_READ_UDATA,
AIOCB_FLUSH_CACHE,
AIOCB_DISCARD_OBJ,
};
struct SheepdogAIOCB {
BlockDriverAIOCB common;
QEMUIOVector *qiov;
int64_t sector_num;
int nb_sectors;
int ret;
enum AIOCBState aiocb_type;
Coroutine *coroutine;
void (*aio_done_func)(SheepdogAIOCB *);
bool canceled;
int nr_pending;
};
typedef struct BDRVSheepdogState {
SheepdogInode inode;
uint32_t min_dirty_data_idx;
uint32_t max_dirty_data_idx;
char name[SD_MAX_VDI_LEN];
bool is_snapshot;
uint32_t cache_flags;
bool discard_supported;
char *host_spec;
bool is_unix;
int fd;
CoMutex lock;
Coroutine *co_send;
Coroutine *co_recv;
uint32_t aioreq_seq_num;
QLIST_HEAD(inflight_aio_head, AIOReq) inflight_aio_head;
QLIST_HEAD(pending_aio_head, AIOReq) pending_aio_head;
} BDRVSheepdogState;
static const char * sd_strerror(int err)
{
int i;
static const struct {
int err;
const char *desc;
} errors[] = {
{SD_RES_SUCCESS, "Success"},
{SD_RES_UNKNOWN, "Unknown error"},
{SD_RES_NO_OBJ, "No object found"},
{SD_RES_EIO, "I/O error"},
{SD_RES_VDI_EXIST, "VDI exists already"},
{SD_RES_INVALID_PARMS, "Invalid parameters"},
{SD_RES_SYSTEM_ERROR, "System error"},
{SD_RES_VDI_LOCKED, "VDI is already locked"},
{SD_RES_NO_VDI, "No vdi found"},
{SD_RES_NO_BASE_VDI, "No base VDI found"},
{SD_RES_VDI_READ, "Failed read the requested VDI"},
{SD_RES_VDI_WRITE, "Failed to write the requested VDI"},
{SD_RES_BASE_VDI_READ, "Failed to read the base VDI"},
{SD_RES_BASE_VDI_WRITE, "Failed to write the base VDI"},
{SD_RES_NO_TAG, "Failed to find the requested tag"},
{SD_RES_STARTUP, "The system is still booting"},
{SD_RES_VDI_NOT_LOCKED, "VDI isn't locked"},
{SD_RES_SHUTDOWN, "The system is shutting down"},
{SD_RES_NO_MEM, "Out of memory on the server"},
{SD_RES_FULL_VDI, "We already have the maximum vdis"},
{SD_RES_VER_MISMATCH, "Protocol version mismatch"},
{SD_RES_NO_SPACE, "Server has no space for new objects"},
{SD_RES_WAIT_FOR_FORMAT, "Sheepdog is waiting for a format operation"},
{SD_RES_WAIT_FOR_JOIN, "Sheepdog is waiting for other nodes joining"},
{SD_RES_JOIN_FAILED, "Target node had failed to join sheepdog"},
{SD_RES_HALT, "Sheepdog is stopped serving IO request"},
{SD_RES_READONLY, "Object is read-only"},
};
for (i = 0; i < ARRAY_SIZE(errors); ++i) {
if (errors[i].err == err) {
return errors[i].desc;
}
}
return "Invalid error code";
}
/*
* Sheepdog I/O handling:
*
* 1. In sd_co_rw_vector, we send the I/O requests to the server and
* link the requests to the inflight_list in the
* BDRVSheepdogState. The function exits without waiting for
* receiving the response.
*
* 2. We receive the response in aio_read_response, the fd handler to
* the sheepdog connection. If metadata update is needed, we send
* the write request to the vdi object in sd_write_done, the write
* completion function. We switch back to sd_co_readv/writev after
* all the requests belonging to the AIOCB are finished.
*/
static inline AIOReq *alloc_aio_req(BDRVSheepdogState *s, SheepdogAIOCB *acb,
uint64_t oid, unsigned int data_len,
uint64_t offset, uint8_t flags,
uint64_t base_oid, unsigned int iov_offset)
{
AIOReq *aio_req;
aio_req = g_malloc(sizeof(*aio_req));
aio_req->aiocb = acb;
aio_req->iov_offset = iov_offset;
aio_req->oid = oid;
aio_req->base_oid = base_oid;
aio_req->offset = offset;
aio_req->data_len = data_len;
aio_req->flags = flags;
aio_req->id = s->aioreq_seq_num++;
acb->nr_pending++;
return aio_req;
}
static inline void free_aio_req(BDRVSheepdogState *s, AIOReq *aio_req)
{
SheepdogAIOCB *acb = aio_req->aiocb;
QLIST_REMOVE(aio_req, aio_siblings);
g_free(aio_req);
acb->nr_pending--;
}
static void coroutine_fn sd_finish_aiocb(SheepdogAIOCB *acb)
{
if (!acb->canceled) {
qemu_coroutine_enter(acb->coroutine, NULL);
}
qemu_aio_release(acb);
}
static void sd_aio_cancel(BlockDriverAIOCB *blockacb)
{
SheepdogAIOCB *acb = (SheepdogAIOCB *)blockacb;
/*
* Sheepdog cannot cancel the requests which are already sent to
* the servers, so we just complete the request with -EIO here.
*/
acb->ret = -EIO;
qemu_coroutine_enter(acb->coroutine, NULL);
acb->canceled = true;
}
static const AIOCBInfo sd_aiocb_info = {
.aiocb_size = sizeof(SheepdogAIOCB),
.cancel = sd_aio_cancel,
};
static SheepdogAIOCB *sd_aio_setup(BlockDriverState *bs, QEMUIOVector *qiov,
int64_t sector_num, int nb_sectors)
{
SheepdogAIOCB *acb;
acb = qemu_aio_get(&sd_aiocb_info, bs, NULL, NULL);
acb->qiov = qiov;
acb->sector_num = sector_num;
acb->nb_sectors = nb_sectors;
acb->aio_done_func = NULL;
acb->canceled = false;
acb->coroutine = qemu_coroutine_self();
acb->ret = 0;
acb->nr_pending = 0;
return acb;
}
static int connect_to_sdog(BDRVSheepdogState *s)
{
int fd;
Error *err = NULL;
if (s->is_unix) {
fd = unix_connect(s->host_spec, &err);
} else {
fd = inet_connect(s->host_spec, &err);
if (err == NULL) {
int ret = socket_set_nodelay(fd);
if (ret < 0) {
error_report("%s", strerror(errno));
}
}
}
if (err != NULL) {
qerror_report_err(err);
error_free(err);
} else {
qemu_set_nonblock(fd);
}
return fd;
}
static coroutine_fn int send_co_req(int sockfd, SheepdogReq *hdr, void *data,
unsigned int *wlen)
{
int ret;
ret = qemu_co_send(sockfd, hdr, sizeof(*hdr));
if (ret < sizeof(*hdr)) {
error_report("failed to send a req, %s", strerror(errno));
return ret;
}
ret = qemu_co_send(sockfd, data, *wlen);
if (ret < *wlen) {
error_report("failed to send a req, %s", strerror(errno));
}
return ret;
}
static void restart_co_req(void *opaque)
{
Coroutine *co = opaque;
qemu_coroutine_enter(co, NULL);
}
static int have_co_req(void *opaque)
{
/* this handler is set only when there is a pending request, so
* always returns 1. */
return 1;
}
typedef struct SheepdogReqCo {
int sockfd;
SheepdogReq *hdr;
void *data;
unsigned int *wlen;
unsigned int *rlen;
int ret;
bool finished;
} SheepdogReqCo;
static coroutine_fn void do_co_req(void *opaque)
{
int ret;
Coroutine *co;
SheepdogReqCo *srco = opaque;
int sockfd = srco->sockfd;
SheepdogReq *hdr = srco->hdr;
void *data = srco->data;
unsigned int *wlen = srco->wlen;
unsigned int *rlen = srco->rlen;
co = qemu_coroutine_self();
qemu_aio_set_fd_handler(sockfd, NULL, restart_co_req, have_co_req, co);
ret = send_co_req(sockfd, hdr, data, wlen);
if (ret < 0) {
goto out;
}
qemu_aio_set_fd_handler(sockfd, restart_co_req, NULL, have_co_req, co);
ret = qemu_co_recv(sockfd, hdr, sizeof(*hdr));
if (ret < sizeof(*hdr)) {
error_report("failed to get a rsp, %s", strerror(errno));
ret = -errno;
goto out;
}
if (*rlen > hdr->data_length) {
*rlen = hdr->data_length;
}
if (*rlen) {
ret = qemu_co_recv(sockfd, data, *rlen);
if (ret < *rlen) {
error_report("failed to get the data, %s", strerror(errno));
ret = -errno;
goto out;
}
}
ret = 0;
out:
/* there is at most one request for this sockfd, so it is safe to
* set each handler to NULL. */
qemu_aio_set_fd_handler(sockfd, NULL, NULL, NULL, NULL);
srco->ret = ret;
srco->finished = true;
}
static int do_req(int sockfd, SheepdogReq *hdr, void *data,
unsigned int *wlen, unsigned int *rlen)
{
Coroutine *co;
SheepdogReqCo srco = {
.sockfd = sockfd,
.hdr = hdr,
.data = data,
.wlen = wlen,
.rlen = rlen,
.ret = 0,
.finished = false,
};
if (qemu_in_coroutine()) {
do_co_req(&srco);
} else {
co = qemu_coroutine_create(do_co_req);
qemu_coroutine_enter(co, &srco);
while (!srco.finished) {
qemu_aio_wait();
}
}
return srco.ret;
}
static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
struct iovec *iov, int niov, bool create,
enum AIOCBState aiocb_type);
static int coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req);
static AIOReq *find_pending_req(BDRVSheepdogState *s, uint64_t oid)
{
AIOReq *aio_req;
QLIST_FOREACH(aio_req, &s->pending_aio_head, aio_siblings) {
if (aio_req->oid == oid) {
return aio_req;
}
}
return NULL;
}
/*
* This function searchs pending requests to the object `oid', and
* sends them.
*/
static void coroutine_fn send_pending_req(BDRVSheepdogState *s, uint64_t oid)
{
AIOReq *aio_req;
SheepdogAIOCB *acb;
int ret;
while ((aio_req = find_pending_req(s, oid)) != NULL) {
acb = aio_req->aiocb;
/* move aio_req from pending list to inflight one */
QLIST_REMOVE(aio_req, aio_siblings);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
ret = add_aio_request(s, aio_req, acb->qiov->iov,
acb->qiov->niov, false, acb->aiocb_type);
if (ret < 0) {
error_report("add_aio_request is failed");
free_aio_req(s, aio_req);
if (!acb->nr_pending) {
sd_finish_aiocb(acb);
}
}
}
}
/*
* Receive responses of the I/O requests.
*
* This function is registered as a fd handler, and called from the
* main loop when s->fd is ready for reading responses.
*/
static void coroutine_fn aio_read_response(void *opaque)
{
SheepdogObjRsp rsp;
BDRVSheepdogState *s = opaque;
int fd = s->fd;
int ret;
AIOReq *aio_req = NULL;
SheepdogAIOCB *acb;
uint64_t idx;
if (QLIST_EMPTY(&s->inflight_aio_head)) {
goto out;
}
/* read a header */
ret = qemu_co_recv(fd, &rsp, sizeof(rsp));
if (ret < 0) {
error_report("failed to get the header, %s", strerror(errno));
goto out;
}
/* find the right aio_req from the inflight aio list */
QLIST_FOREACH(aio_req, &s->inflight_aio_head, aio_siblings) {
if (aio_req->id == rsp.id) {
break;
}
}
if (!aio_req) {
error_report("cannot find aio_req %x", rsp.id);
goto out;
}
acb = aio_req->aiocb;
switch (acb->aiocb_type) {
case AIOCB_WRITE_UDATA:
/* this coroutine context is no longer suitable for co_recv
* because we may send data to update vdi objects */
s->co_recv = NULL;
if (!is_data_obj(aio_req->oid)) {
break;
}
idx = data_oid_to_idx(aio_req->oid);
if (s->inode.data_vdi_id[idx] != s->inode.vdi_id) {
/*
* If the object is newly created one, we need to update
* the vdi object (metadata object). min_dirty_data_idx
* and max_dirty_data_idx are changed to include updated
* index between them.
*/
if (rsp.result == SD_RES_SUCCESS) {
s->inode.data_vdi_id[idx] = s->inode.vdi_id;
s->max_dirty_data_idx = MAX(idx, s->max_dirty_data_idx);
s->min_dirty_data_idx = MIN(idx, s->min_dirty_data_idx);
}
/*
* Some requests may be blocked because simultaneous
* create requests are not allowed, so we search the
* pending requests here.
*/
send_pending_req(s, aio_req->oid);
}
break;
case AIOCB_READ_UDATA:
ret = qemu_co_recvv(fd, acb->qiov->iov, acb->qiov->niov,
aio_req->iov_offset, rsp.data_length);
if (ret < 0) {
error_report("failed to get the data, %s", strerror(errno));
goto out;
}
break;
case AIOCB_FLUSH_CACHE:
if (rsp.result == SD_RES_INVALID_PARMS) {
dprintf("disable cache since the server doesn't support it\n");
s->cache_flags = SD_FLAG_CMD_DIRECT;
rsp.result = SD_RES_SUCCESS;
}
break;
case AIOCB_DISCARD_OBJ:
switch (rsp.result) {
case SD_RES_INVALID_PARMS:
error_report("sheep(%s) doesn't support discard command",
s->host_spec);
rsp.result = SD_RES_SUCCESS;
s->discard_supported = false;
break;
case SD_RES_SUCCESS:
idx = data_oid_to_idx(aio_req->oid);
s->inode.data_vdi_id[idx] = 0;
break;
default:
break;
}
}
switch (rsp.result) {
case SD_RES_SUCCESS:
break;
case SD_RES_READONLY:
ret = resend_aioreq(s, aio_req);
if (ret == SD_RES_SUCCESS) {
goto out;
}
/* fall through */
default:
acb->ret = -EIO;
error_report("%s", sd_strerror(rsp.result));
break;
}
free_aio_req(s, aio_req);
if (!acb->nr_pending) {
/*
* We've finished all requests which belong to the AIOCB, so
* we can switch back to sd_co_readv/writev now.
*/
acb->aio_done_func(acb);
}
out:
s->co_recv = NULL;
}
static void co_read_response(void *opaque)
{
BDRVSheepdogState *s = opaque;
if (!s->co_recv) {
s->co_recv = qemu_coroutine_create(aio_read_response);
}
qemu_coroutine_enter(s->co_recv, opaque);
}
static void co_write_request(void *opaque)
{
BDRVSheepdogState *s = opaque;
qemu_coroutine_enter(s->co_send, NULL);
}
static int aio_flush_request(void *opaque)
{
BDRVSheepdogState *s = opaque;
return !QLIST_EMPTY(&s->inflight_aio_head) ||
!QLIST_EMPTY(&s->pending_aio_head);
}
/*
* Return a socket discriptor to read/write objects.
*
* We cannot use this discriptor for other operations because
* the block driver may be on waiting response from the server.
*/
static int get_sheep_fd(BDRVSheepdogState *s)
{
int fd;
fd = connect_to_sdog(s);
if (fd < 0) {
return fd;
}
qemu_aio_set_fd_handler(fd, co_read_response, NULL, aio_flush_request, s);
return fd;
}
static int sd_parse_uri(BDRVSheepdogState *s, const char *filename,
char *vdi, uint32_t *snapid, char *tag)
{
URI *uri;
QueryParams *qp = NULL;
int ret = 0;
uri = uri_parse(filename);
if (!uri) {
return -EINVAL;
}
/* transport */
if (!strcmp(uri->scheme, "sheepdog")) {
s->is_unix = false;
} else if (!strcmp(uri->scheme, "sheepdog+tcp")) {
s->is_unix = false;
} else if (!strcmp(uri->scheme, "sheepdog+unix")) {
s->is_unix = true;
} else {
ret = -EINVAL;
goto out;
}
if (uri->path == NULL || !strcmp(uri->path, "/")) {
ret = -EINVAL;
goto out;
}
pstrcpy(vdi, SD_MAX_VDI_LEN, uri->path + 1);
qp = query_params_parse(uri->query);
if (qp->n > 1 || (s->is_unix && !qp->n) || (!s->is_unix && qp->n)) {
ret = -EINVAL;
goto out;
}
if (s->is_unix) {
/* sheepdog+unix:///vdiname?socket=path */
if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
ret = -EINVAL;
goto out;
}
s->host_spec = g_strdup(qp->p[0].value);
} else {
/* sheepdog[+tcp]://[host:port]/vdiname */
s->host_spec = g_strdup_printf("%s:%d", uri->server ?: SD_DEFAULT_ADDR,
uri->port ?: SD_DEFAULT_PORT);
}
/* snapshot tag */
if (uri->fragment) {
*snapid = strtoul(uri->fragment, NULL, 10);
if (*snapid == 0) {
pstrcpy(tag, SD_MAX_VDI_TAG_LEN, uri->fragment);
}
} else {
*snapid = CURRENT_VDI_ID; /* search current vdi */
}
out:
if (qp) {
query_params_free(qp);
}
uri_free(uri);
return ret;
}
/*
* Parse a filename (old syntax)
*
* filename must be one of the following formats:
* 1. [vdiname]
* 2. [vdiname]:[snapid]
* 3. [vdiname]:[tag]
* 4. [hostname]:[port]:[vdiname]
* 5. [hostname]:[port]:[vdiname]:[snapid]
* 6. [hostname]:[port]:[vdiname]:[tag]
*
* You can boot from the snapshot images by specifying `snapid` or
* `tag'.
*
* You can run VMs outside the Sheepdog cluster by specifying
* `hostname' and `port' (experimental).
*/
static int parse_vdiname(BDRVSheepdogState *s, const char *filename,
char *vdi, uint32_t *snapid, char *tag)
{
char *p, *q, *uri;
const char *host_spec, *vdi_spec;
int nr_sep, ret;
strstart(filename, "sheepdog:", (const char **)&filename);
p = q = g_strdup(filename);
/* count the number of separators */
nr_sep = 0;
while (*p) {
if (*p == ':') {
nr_sep++;
}
p++;
}
p = q;
/* use the first two tokens as host_spec. */
if (nr_sep >= 2) {
host_spec = p;
p = strchr(p, ':');
p++;
p = strchr(p, ':');
*p++ = '\0';
} else {
host_spec = "";
}
vdi_spec = p;
p = strchr(vdi_spec, ':');
if (p) {
*p++ = '#';
}
uri = g_strdup_printf("sheepdog://%s/%s", host_spec, vdi_spec);
ret = sd_parse_uri(s, uri, vdi, snapid, tag);
g_free(q);
g_free(uri);
return ret;
}
static int find_vdi_name(BDRVSheepdogState *s, const char *filename,
uint32_t snapid, const char *tag, uint32_t *vid,
bool lock)
{
int ret, fd;
SheepdogVdiReq hdr;
SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
unsigned int wlen, rlen = 0;
char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN];
fd = connect_to_sdog(s);
if (fd < 0) {
return fd;
}
/* This pair of strncpy calls ensures that the buffer is zero-filled,
* which is desirable since we'll soon be sending those bytes, and
* don't want the send_req to read uninitialized data.
*/
strncpy(buf, filename, SD_MAX_VDI_LEN);
strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN);
memset(&hdr, 0, sizeof(hdr));
if (lock) {
hdr.opcode = SD_OP_LOCK_VDI;
} else {
hdr.opcode = SD_OP_GET_VDI_INFO;
}
wlen = SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN;
hdr.proto_ver = SD_PROTO_VER;
hdr.data_length = wlen;
hdr.snapid = snapid;
hdr.flags = SD_FLAG_CMD_WRITE;
ret = do_req(fd, (SheepdogReq *)&hdr, buf, &wlen, &rlen);
if (ret) {
goto out;
}
if (rsp->result != SD_RES_SUCCESS) {
error_report("cannot get vdi info, %s, %s %d %s",
sd_strerror(rsp->result), filename, snapid, tag);
if (rsp->result == SD_RES_NO_VDI) {
ret = -ENOENT;
} else {
ret = -EIO;
}
goto out;
}
*vid = rsp->vdi_id;
ret = 0;
out:
closesocket(fd);
return ret;
}
static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
struct iovec *iov, int niov, bool create,
enum AIOCBState aiocb_type)
{
int nr_copies = s->inode.nr_copies;
SheepdogObjReq hdr;
unsigned int wlen = 0;
int ret;
uint64_t oid = aio_req->oid;
unsigned int datalen = aio_req->data_len;
uint64_t offset = aio_req->offset;
uint8_t flags = aio_req->flags;
uint64_t old_oid = aio_req->base_oid;
if (!nr_copies) {
error_report("bug");
}
memset(&hdr, 0, sizeof(hdr));
switch (aiocb_type) {
case AIOCB_FLUSH_CACHE:
hdr.opcode = SD_OP_FLUSH_VDI;
break;
case AIOCB_READ_UDATA:
hdr.opcode = SD_OP_READ_OBJ;
hdr.flags = flags;
break;
case AIOCB_WRITE_UDATA:
if (create) {
hdr.opcode = SD_OP_CREATE_AND_WRITE_OBJ;
} else {
hdr.opcode = SD_OP_WRITE_OBJ;
}
wlen = datalen;
hdr.flags = SD_FLAG_CMD_WRITE | flags;
break;
case AIOCB_DISCARD_OBJ:
hdr.opcode = SD_OP_DISCARD_OBJ;
break;
}
if (s->cache_flags) {
hdr.flags |= s->cache_flags;
}
hdr.oid = oid;
hdr.cow_oid = old_oid;
hdr.copies = s->inode.nr_copies;
hdr.data_length = datalen;
hdr.offset = offset;
hdr.id = aio_req->id;
qemu_co_mutex_lock(&s->lock);
s->co_send = qemu_coroutine_self();
qemu_aio_set_fd_handler(s->fd, co_read_response, co_write_request,
aio_flush_request, s);
socket_set_cork(s->fd, 1);
/* send a header */
ret = qemu_co_send(s->fd, &hdr, sizeof(hdr));
if (ret < 0) {
qemu_co_mutex_unlock(&s->lock);
error_report("failed to send a req, %s", strerror(errno));
return -errno;
}
if (wlen) {
ret = qemu_co_sendv(s->fd, iov, niov, aio_req->iov_offset, wlen);
if (ret < 0) {
qemu_co_mutex_unlock(&s->lock);
error_report("failed to send a data, %s", strerror(errno));
return -errno;
}
}
socket_set_cork(s->fd, 0);
qemu_aio_set_fd_handler(s->fd, co_read_response, NULL,
aio_flush_request, s);
qemu_co_mutex_unlock(&s->lock);
return 0;
}
static int read_write_object(int fd, char *buf, uint64_t oid, int copies,
unsigned int datalen, uint64_t offset,
bool write, bool create, uint32_t cache_flags)
{
SheepdogObjReq hdr;
SheepdogObjRsp *rsp = (SheepdogObjRsp *)&hdr;
unsigned int wlen, rlen;
int ret;
memset(&hdr, 0, sizeof(hdr));
if (write) {
wlen = datalen;
rlen = 0;
hdr.flags = SD_FLAG_CMD_WRITE;
if (create) {
hdr.opcode = SD_OP_CREATE_AND_WRITE_OBJ;
} else {
hdr.opcode = SD_OP_WRITE_OBJ;
}
} else {
wlen = 0;
rlen = datalen;
hdr.opcode = SD_OP_READ_OBJ;
}
hdr.flags |= cache_flags;
hdr.oid = oid;
hdr.data_length = datalen;
hdr.offset = offset;
hdr.copies = copies;
ret = do_req(fd, (SheepdogReq *)&hdr, buf, &wlen, &rlen);
if (ret) {
error_report("failed to send a request to the sheep");
return ret;
}
switch (rsp->result) {
case SD_RES_SUCCESS:
return 0;
default:
error_report("%s", sd_strerror(rsp->result));
return -EIO;
}
}
static int read_object(int fd, char *buf, uint64_t oid, int copies,
unsigned int datalen, uint64_t offset,
uint32_t cache_flags)
{
return read_write_object(fd, buf, oid, copies, datalen, offset, false,
false, cache_flags);
}
static int write_object(int fd, char *buf, uint64_t oid, int copies,
unsigned int datalen, uint64_t offset, bool create,
uint32_t cache_flags)
{
return read_write_object(fd, buf, oid, copies, datalen, offset, true,
create, cache_flags);
}
/* update inode with the latest state */
static int reload_inode(BDRVSheepdogState *s, uint32_t snapid, const char *tag)
{
SheepdogInode *inode;
int ret = 0, fd;
uint32_t vid = 0;
fd = connect_to_sdog(s);
if (fd < 0) {
return -EIO;
}
inode = g_malloc(sizeof(s->inode));
ret = find_vdi_name(s, s->name, snapid, tag, &vid, false);
if (ret) {
goto out;
}
ret = read_object(fd, (char *)inode, vid_to_vdi_oid(vid),
s->inode.nr_copies, sizeof(*inode), 0, s->cache_flags);
if (ret < 0) {
goto out;
}
if (inode->vdi_id != s->inode.vdi_id) {
memcpy(&s->inode, inode, sizeof(s->inode));
}
out:
g_free(inode);
closesocket(fd);
return ret;
}
static int coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req)
{
SheepdogAIOCB *acb = aio_req->aiocb;
bool create = false;
int ret;
ret = reload_inode(s, 0, "");
if (ret < 0) {
return ret;
}
aio_req->oid = vid_to_data_oid(s->inode.vdi_id,
data_oid_to_idx(aio_req->oid));
/* check whether this request becomes a CoW one */
if (acb->aiocb_type == AIOCB_WRITE_UDATA) {
int idx = data_oid_to_idx(aio_req->oid);
AIOReq *areq;
if (s->inode.data_vdi_id[idx] == 0) {
create = true;
goto out;
}
if (is_data_obj_writable(&s->inode, idx)) {
goto out;
}
/* link to the pending list if there is another CoW request to
* the same object */
QLIST_FOREACH(areq, &s->inflight_aio_head, aio_siblings) {
if (areq != aio_req && areq->oid == aio_req->oid) {
dprintf("simultaneous CoW to %" PRIx64 "\n", aio_req->oid);
QLIST_REMOVE(aio_req, aio_siblings);
QLIST_INSERT_HEAD(&s->pending_aio_head, aio_req, aio_siblings);
return SD_RES_SUCCESS;
}
}
aio_req->base_oid = vid_to_data_oid(s->inode.data_vdi_id[idx], idx);
aio_req->flags |= SD_FLAG_CMD_COW;
create = true;
}
out:
return add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
create, acb->aiocb_type);
}
/* TODO Convert to fine grained options */
static QemuOptsList runtime_opts = {
.name = "sheepdog",
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
.desc = {
{
.name = "filename",
.type = QEMU_OPT_STRING,
.help = "URL to the sheepdog image",
},
{ /* end of list */ }
},
};
static int sd_open(BlockDriverState *bs, QDict *options, int flags)
{
int ret, fd;
uint32_t vid = 0;
BDRVSheepdogState *s = bs->opaque;
char vdi[SD_MAX_VDI_LEN], tag[SD_MAX_VDI_TAG_LEN];
uint32_t snapid;
char *buf = NULL;
QemuOpts *opts;
Error *local_err = NULL;
const char *filename;
opts = qemu_opts_create_nofail(&runtime_opts);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (error_is_set(&local_err)) {
qerror_report_err(local_err);
error_free(local_err);
ret = -EINVAL;
goto out;
}
filename = qemu_opt_get(opts, "filename");
QLIST_INIT(&s->inflight_aio_head);
QLIST_INIT(&s->pending_aio_head);
s->fd = -1;
memset(vdi, 0, sizeof(vdi));
memset(tag, 0, sizeof(tag));
if (strstr(filename, "://")) {
ret = sd_parse_uri(s, filename, vdi, &snapid, tag);
} else {
ret = parse_vdiname(s, filename, vdi, &snapid, tag);
}
if (ret < 0) {
goto out;
}
s->fd = get_sheep_fd(s);
if (s->fd < 0) {
ret = s->fd;
goto out;
}
ret = find_vdi_name(s, vdi, snapid, tag, &vid, true);
if (ret) {
goto out;
}
/*
* QEMU block layer emulates writethrough cache as 'writeback + flush', so
* we always set SD_FLAG_CMD_CACHE (writeback cache) as default.
*/
s->cache_flags = SD_FLAG_CMD_CACHE;
if (flags & BDRV_O_NOCACHE) {
s->cache_flags = SD_FLAG_CMD_DIRECT;
}
s->discard_supported = true;
if (snapid || tag[0] != '\0') {
dprintf("%" PRIx32 " snapshot inode was open.\n", vid);
s->is_snapshot = true;
}
fd = connect_to_sdog(s);
if (fd < 0) {
ret = fd;
goto out;
}
buf = g_malloc(SD_INODE_SIZE);
ret = read_object(fd, buf, vid_to_vdi_oid(vid), 0, SD_INODE_SIZE, 0,
s->cache_flags);
closesocket(fd);
if (ret) {
goto out;
}
memcpy(&s->inode, buf, sizeof(s->inode));
s->min_dirty_data_idx = UINT32_MAX;
s->max_dirty_data_idx = 0;
bs->total_sectors = s->inode.vdi_size / BDRV_SECTOR_SIZE;
pstrcpy(s->name, sizeof(s->name), vdi);
qemu_co_mutex_init(&s->lock);
qemu_opts_del(opts);
g_free(buf);
return 0;
out:
qemu_aio_set_fd_handler(s->fd, NULL, NULL, NULL, NULL);
if (s->fd >= 0) {
closesocket(s->fd);
}
qemu_opts_del(opts);
g_free(buf);
return ret;
}
static int do_sd_create(BDRVSheepdogState *s, char *filename, int64_t vdi_size,
uint32_t base_vid, uint32_t *vdi_id, int snapshot)
{
SheepdogVdiReq hdr;
SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
int fd, ret;
unsigned int wlen, rlen = 0;
char buf[SD_MAX_VDI_LEN];
fd = connect_to_sdog(s);
if (fd < 0) {
return fd;
}
/* FIXME: would it be better to fail (e.g., return -EIO) when filename
* does not fit in buf? For now, just truncate and avoid buffer overrun.
*/
memset(buf, 0, sizeof(buf));
pstrcpy(buf, sizeof(buf), filename);
memset(&hdr, 0, sizeof(hdr));
hdr.opcode = SD_OP_NEW_VDI;
hdr.vdi_id = base_vid;
wlen = SD_MAX_VDI_LEN;
hdr.flags = SD_FLAG_CMD_WRITE;
hdr.snapid = snapshot;
hdr.data_length = wlen;
hdr.vdi_size = vdi_size;
ret = do_req(fd, (SheepdogReq *)&hdr, buf, &wlen, &rlen);
closesocket(fd);
if (ret) {
return ret;
}
if (rsp->result != SD_RES_SUCCESS) {
error_report("%s, %s", sd_strerror(rsp->result), filename);
return -EIO;
}
if (vdi_id) {
*vdi_id = rsp->vdi_id;
}
return 0;
}
static int sd_prealloc(const char *filename)
{
BlockDriverState *bs = NULL;
uint32_t idx, max_idx;
int64_t vdi_size;
void *buf = g_malloc0(SD_DATA_OBJ_SIZE);
int ret;
ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR);
if (ret < 0) {
goto out;
}
vdi_size = bdrv_getlength(bs);
if (vdi_size < 0) {
ret = vdi_size;
goto out;
}
max_idx = DIV_ROUND_UP(vdi_size, SD_DATA_OBJ_SIZE);
for (idx = 0; idx < max_idx; idx++) {
/*
* The created image can be a cloned image, so we need to read
* a data from the source image.
*/
ret = bdrv_pread(bs, idx * SD_DATA_OBJ_SIZE, buf, SD_DATA_OBJ_SIZE);
if (ret < 0) {
goto out;
}
ret = bdrv_pwrite(bs, idx * SD_DATA_OBJ_SIZE, buf, SD_DATA_OBJ_SIZE);
if (ret < 0) {
goto out;
}
}
out:
if (bs) {
bdrv_delete(bs);
}
g_free(buf);
return ret;
}
static int sd_create(const char *filename, QEMUOptionParameter *options)
{
int ret = 0;
uint32_t vid = 0, base_vid = 0;
int64_t vdi_size = 0;
char *backing_file = NULL;
BDRVSheepdogState *s;
char vdi[SD_MAX_VDI_LEN], tag[SD_MAX_VDI_TAG_LEN];
uint32_t snapid;
bool prealloc = false;
s = g_malloc0(sizeof(BDRVSheepdogState));
memset(vdi, 0, sizeof(vdi));
memset(tag, 0, sizeof(tag));
if (strstr(filename, "://")) {
ret = sd_parse_uri(s, filename, vdi, &snapid, tag);
} else {
ret = parse_vdiname(s, filename, vdi, &snapid, tag);
}
if (ret < 0) {
goto out;
}
while (options && options->name) {
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
vdi_size = options->value.n;
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
backing_file = options->value.s;
} else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) {
if (!options->value.s || !strcmp(options->value.s, "off")) {
prealloc = false;
} else if (!strcmp(options->value.s, "full")) {
prealloc = true;
} else {
error_report("Invalid preallocation mode: '%s'",
options->value.s);
ret = -EINVAL;
goto out;
}
}
options++;
}
if (vdi_size > SD_MAX_VDI_SIZE) {
error_report("too big image size");
ret = -EINVAL;
goto out;
}
if (backing_file) {
BlockDriverState *bs;
BDRVSheepdogState *s;
BlockDriver *drv;
/* Currently, only Sheepdog backing image is supported. */
drv = bdrv_find_protocol(backing_file);
if (!drv || strcmp(drv->protocol_name, "sheepdog") != 0) {
error_report("backing_file must be a sheepdog image");
ret = -EINVAL;
goto out;
}
ret = bdrv_file_open(&bs, backing_file, NULL, 0);
if (ret < 0) {
goto out;
}
s = bs->opaque;
if (!is_snapshot(&s->inode)) {
error_report("cannot clone from a non snapshot vdi");
bdrv_delete(bs);
ret = -EINVAL;
goto out;
}
base_vid = s->inode.vdi_id;
bdrv_delete(bs);
}
ret = do_sd_create(s, vdi, vdi_size, base_vid, &vid, 0);
if (!prealloc || ret) {
goto out;
}
ret = sd_prealloc(filename);
out:
g_free(s);
return ret;
}
static void sd_close(BlockDriverState *bs)
{
BDRVSheepdogState *s = bs->opaque;
SheepdogVdiReq hdr;
SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
unsigned int wlen, rlen = 0;
int fd, ret;
dprintf("%s\n", s->name);
fd = connect_to_sdog(s);
if (fd < 0) {
return;
}
memset(&hdr, 0, sizeof(hdr));
hdr.opcode = SD_OP_RELEASE_VDI;
hdr.vdi_id = s->inode.vdi_id;
wlen = strlen(s->name) + 1;
hdr.data_length = wlen;
hdr.flags = SD_FLAG_CMD_WRITE;
ret = do_req(fd, (SheepdogReq *)&hdr, s->name, &wlen, &rlen);
closesocket(fd);
if (!ret && rsp->result != SD_RES_SUCCESS &&
rsp->result != SD_RES_VDI_NOT_LOCKED) {
error_report("%s, %s", sd_strerror(rsp->result), s->name);
}
qemu_aio_set_fd_handler(s->fd, NULL, NULL, NULL, NULL);
closesocket(s->fd);
g_free(s->host_spec);
}
static int64_t sd_getlength(BlockDriverState *bs)
{
BDRVSheepdogState *s = bs->opaque;
return s->inode.vdi_size;
}
static int sd_truncate(BlockDriverState *bs, int64_t offset)
{
BDRVSheepdogState *s = bs->opaque;
int ret, fd;
unsigned int datalen;
if (offset < s->inode.vdi_size) {
error_report("shrinking is not supported");
return -EINVAL;
} else if (offset > SD_MAX_VDI_SIZE) {
error_report("too big image size");
return -EINVAL;
}
fd = connect_to_sdog(s);
if (fd < 0) {
return fd;
}
/* we don't need to update entire object */
datalen = SD_INODE_SIZE - sizeof(s->inode.data_vdi_id);
s->inode.vdi_size = offset;
ret = write_object(fd, (char *)&s->inode, vid_to_vdi_oid(s->inode.vdi_id),
s->inode.nr_copies, datalen, 0, false, s->cache_flags);
close(fd);
if (ret < 0) {
error_report("failed to update an inode.");
}
return ret;
}
/*
* This function is called after writing data objects. If we need to
* update metadata, this sends a write request to the vdi object.
* Otherwise, this switches back to sd_co_readv/writev.
*/
static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
{
int ret;
BDRVSheepdogState *s = acb->common.bs->opaque;
struct iovec iov;
AIOReq *aio_req;
uint32_t offset, data_len, mn, mx;
mn = s->min_dirty_data_idx;
mx = s->max_dirty_data_idx;
if (mn <= mx) {
/* we need to update the vdi object. */
offset = sizeof(s->inode) - sizeof(s->inode.data_vdi_id) +
mn * sizeof(s->inode.data_vdi_id[0]);
data_len = (mx - mn + 1) * sizeof(s->inode.data_vdi_id[0]);
s->min_dirty_data_idx = UINT32_MAX;
s->max_dirty_data_idx = 0;
iov.iov_base = &s->inode;
iov.iov_len = sizeof(s->inode);
aio_req = alloc_aio_req(s, acb, vid_to_vdi_oid(s->inode.vdi_id),
data_len, offset, 0, 0, offset);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
ret = add_aio_request(s, aio_req, &iov, 1, false, AIOCB_WRITE_UDATA);
if (ret) {
free_aio_req(s, aio_req);
acb->ret = -EIO;
goto out;
}
acb->aio_done_func = sd_finish_aiocb;
acb->aiocb_type = AIOCB_WRITE_UDATA;
return;
}
out:
sd_finish_aiocb(acb);
}
/* Delete current working VDI on the snapshot chain */
static bool sd_delete(BDRVSheepdogState *s)
{
unsigned int wlen = SD_MAX_VDI_LEN, rlen = 0;
SheepdogVdiReq hdr = {
.opcode = SD_OP_DEL_VDI,
.vdi_id = s->inode.vdi_id,
.data_length = wlen,
.flags = SD_FLAG_CMD_WRITE,
};
SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
int fd, ret;
fd = connect_to_sdog(s);
if (fd < 0) {
return false;
}
ret = do_req(fd, (SheepdogReq *)&hdr, s->name, &wlen, &rlen);
closesocket(fd);
if (ret) {
return false;
}
switch (rsp->result) {
case SD_RES_NO_VDI:
error_report("%s was already deleted", s->name);
/* fall through */
case SD_RES_SUCCESS:
break;
default:
error_report("%s, %s", sd_strerror(rsp->result), s->name);
return false;
}
return true;
}
/*
* Create a writable VDI from a snapshot
*/
static int sd_create_branch(BDRVSheepdogState *s)
{
int ret, fd;
uint32_t vid;
char *buf;
bool deleted;
dprintf("%" PRIx32 " is snapshot.\n", s->inode.vdi_id);
buf = g_malloc(SD_INODE_SIZE);
/*
* Even If deletion fails, we will just create extra snapshot based on
* the workding VDI which was supposed to be deleted. So no need to
* false bail out.
*/
deleted = sd_delete(s);
ret = do_sd_create(s, s->name, s->inode.vdi_size, s->inode.vdi_id, &vid,
!deleted);
if (ret) {
goto out;
}
dprintf("%" PRIx32 " is created.\n", vid);
fd = connect_to_sdog(s);
if (fd < 0) {
ret = fd;
goto out;
}
ret = read_object(fd, buf, vid_to_vdi_oid(vid), s->inode.nr_copies,
SD_INODE_SIZE, 0, s->cache_flags);
closesocket(fd);
if (ret < 0) {
goto out;
}
memcpy(&s->inode, buf, sizeof(s->inode));
s->is_snapshot = false;
ret = 0;
dprintf("%" PRIx32 " was newly created.\n", s->inode.vdi_id);
out:
g_free(buf);
return ret;
}
/*
* Send I/O requests to the server.
*
* This function sends requests to the server, links the requests to
* the inflight_list in BDRVSheepdogState, and exits without
* waiting the response. The responses are received in the
* `aio_read_response' function which is called from the main loop as
* a fd handler.
*
* Returns 1 when we need to wait a response, 0 when there is no sent
* request and -errno in error cases.
*/
static int coroutine_fn sd_co_rw_vector(void *p)
{
SheepdogAIOCB *acb = p;
int ret = 0;
unsigned long len, done = 0, total = acb->nb_sectors * BDRV_SECTOR_SIZE;
unsigned long idx = acb->sector_num * BDRV_SECTOR_SIZE / SD_DATA_OBJ_SIZE;
uint64_t oid;
uint64_t offset = (acb->sector_num * BDRV_SECTOR_SIZE) % SD_DATA_OBJ_SIZE;
BDRVSheepdogState *s = acb->common.bs->opaque;
SheepdogInode *inode = &s->inode;
AIOReq *aio_req;
if (acb->aiocb_type == AIOCB_WRITE_UDATA && s->is_snapshot) {
/*
* In the case we open the snapshot VDI, Sheepdog creates the
* writable VDI when we do a write operation first.
*/
ret = sd_create_branch(s);
if (ret) {
acb->ret = -EIO;
goto out;
}
}
/*
* Make sure we don't free the aiocb before we are done with all requests.
* This additional reference is dropped at the end of this function.
*/
acb->nr_pending++;
while (done != total) {
uint8_t flags = 0;
uint64_t old_oid = 0;
bool create = false;
oid = vid_to_data_oid(inode->data_vdi_id[idx], idx);
len = MIN(total - done, SD_DATA_OBJ_SIZE - offset);
switch (acb->aiocb_type) {
case AIOCB_READ_UDATA:
if (!inode->data_vdi_id[idx]) {
qemu_iovec_memset(acb->qiov, done, 0, len);
goto done;
}
break;
case AIOCB_WRITE_UDATA:
if (!inode->data_vdi_id[idx]) {
create = true;
} else if (!is_data_obj_writable(inode, idx)) {
/* Copy-On-Write */
create = true;
old_oid = oid;
flags = SD_FLAG_CMD_COW;
}
break;
case AIOCB_DISCARD_OBJ:
/*
* We discard the object only when the whole object is
* 1) allocated 2) trimmed. Otherwise, simply skip it.
*/
if (len != SD_DATA_OBJ_SIZE || inode->data_vdi_id[idx] == 0) {
goto done;
}
break;
default:
break;
}
if (create) {
dprintf("update ino (%" PRIu32 ") %" PRIu64 " %" PRIu64 " %ld\n",
inode->vdi_id, oid,
vid_to_data_oid(inode->data_vdi_id[idx], idx), idx);
oid = vid_to_data_oid(inode->vdi_id, idx);
dprintf("new oid %" PRIx64 "\n", oid);
}
aio_req = alloc_aio_req(s, acb, oid, len, offset, flags, old_oid, done);
if (create) {
AIOReq *areq;
QLIST_FOREACH(areq, &s->inflight_aio_head, aio_siblings) {
if (areq->oid == oid) {
/*
* Sheepdog cannot handle simultaneous create
* requests to the same object. So we cannot send
* the request until the previous request
* finishes.
*/
aio_req->flags = 0;
aio_req->base_oid = 0;
QLIST_INSERT_HEAD(&s->pending_aio_head, aio_req,
aio_siblings);
goto done;
}
}
}
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
ret = add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
create, acb->aiocb_type);
if (ret < 0) {
error_report("add_aio_request is failed");
free_aio_req(s, aio_req);
acb->ret = -EIO;
goto out;
}
done:
offset = 0;
idx++;
done += len;
}
out:
if (!--acb->nr_pending) {
return acb->ret;
}
return 1;
}
static coroutine_fn int sd_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
SheepdogAIOCB *acb;
int ret;
if (bs->growable && sector_num + nb_sectors > bs->total_sectors) {
ret = sd_truncate(bs, (sector_num + nb_sectors) * BDRV_SECTOR_SIZE);
if (ret < 0) {
return ret;
}
bs->total_sectors = sector_num + nb_sectors;
}
acb = sd_aio_setup(bs, qiov, sector_num, nb_sectors);
acb->aio_done_func = sd_write_done;
acb->aiocb_type = AIOCB_WRITE_UDATA;
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
qemu_aio_release(acb);
return ret;
}
qemu_coroutine_yield();
return acb->ret;
}
static coroutine_fn int sd_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
SheepdogAIOCB *acb;
int ret;
acb = sd_aio_setup(bs, qiov, sector_num, nb_sectors);
acb->aiocb_type = AIOCB_READ_UDATA;
acb->aio_done_func = sd_finish_aiocb;
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
qemu_aio_release(acb);
return ret;
}
qemu_coroutine_yield();
return acb->ret;
}
static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
{
BDRVSheepdogState *s = bs->opaque;
SheepdogAIOCB *acb;
AIOReq *aio_req;
int ret;
if (s->cache_flags != SD_FLAG_CMD_CACHE) {
return 0;
}
acb = sd_aio_setup(bs, NULL, 0, 0);
acb->aiocb_type = AIOCB_FLUSH_CACHE;
acb->aio_done_func = sd_finish_aiocb;
aio_req = alloc_aio_req(s, acb, vid_to_vdi_oid(s->inode.vdi_id),
0, 0, 0, 0, 0);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
ret = add_aio_request(s, aio_req, NULL, 0, false, acb->aiocb_type);
if (ret < 0) {
error_report("add_aio_request is failed");
free_aio_req(s, aio_req);
qemu_aio_release(acb);
return ret;
}
qemu_coroutine_yield();
return acb->ret;
}
static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
{
BDRVSheepdogState *s = bs->opaque;
int ret, fd;
uint32_t new_vid;
SheepdogInode *inode;
unsigned int datalen;
dprintf("sn_info: name %s id_str %s s: name %s vm_state_size %" PRId64 " "
"is_snapshot %d\n", sn_info->name, sn_info->id_str,
s->name, sn_info->vm_state_size, s->is_snapshot);
if (s->is_snapshot) {
error_report("You can't create a snapshot of a snapshot VDI, "
"%s (%" PRIu32 ").", s->name, s->inode.vdi_id);
return -EINVAL;
}
dprintf("%s %s\n", sn_info->name, sn_info->id_str);
s->inode.vm_state_size = sn_info->vm_state_size;
s->inode.vm_clock_nsec = sn_info->vm_clock_nsec;
/* It appears that inode.tag does not require a NUL terminator,
* which means this use of strncpy is ok.
*/
strncpy(s->inode.tag, sn_info->name, sizeof(s->inode.tag));
/* we don't need to update entire object */
datalen = SD_INODE_SIZE - sizeof(s->inode.data_vdi_id);
/* refresh inode. */
fd = connect_to_sdog(s);
if (fd < 0) {
ret = fd;
goto cleanup;
}
ret = write_object(fd, (char *)&s->inode, vid_to_vdi_oid(s->inode.vdi_id),
s->inode.nr_copies, datalen, 0, false, s->cache_flags);
if (ret < 0) {
error_report("failed to write snapshot's inode.");
goto cleanup;
}
ret = do_sd_create(s, s->name, s->inode.vdi_size, s->inode.vdi_id, &new_vid,
1);
if (ret < 0) {
error_report("failed to create inode for snapshot. %s",
strerror(errno));
goto cleanup;
}
inode = (SheepdogInode *)g_malloc(datalen);
ret = read_object(fd, (char *)inode, vid_to_vdi_oid(new_vid),
s->inode.nr_copies, datalen, 0, s->cache_flags);
if (ret < 0) {
error_report("failed to read new inode info. %s", strerror(errno));
goto cleanup;
}
memcpy(&s->inode, inode, datalen);
dprintf("s->inode: name %s snap_id %x oid %x\n",
s->inode.name, s->inode.snap_id, s->inode.vdi_id);
cleanup:
closesocket(fd);
return ret;
}
/*
* We implement rollback(loadvm) operation to the specified snapshot by
* 1) switch to the snapshot
* 2) rely on sd_create_branch to delete working VDI and
* 3) create a new working VDI based on the speicified snapshot
*/
static int sd_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
{
BDRVSheepdogState *s = bs->opaque;
BDRVSheepdogState *old_s;
char tag[SD_MAX_VDI_TAG_LEN];
uint32_t snapid = 0;
int ret = 0;
old_s = g_malloc(sizeof(BDRVSheepdogState));
memcpy(old_s, s, sizeof(BDRVSheepdogState));
snapid = strtoul(snapshot_id, NULL, 10);
if (snapid) {
tag[0] = 0;
} else {
pstrcpy(tag, sizeof(tag), s->name);
}
ret = reload_inode(s, snapid, tag);
if (ret) {
goto out;
}
if (!s->inode.vm_state_size) {
error_report("Invalid snapshot");
ret = -ENOENT;
goto out;
}
s->is_snapshot = true;
g_free(old_s);
return 0;
out:
/* recover bdrv_sd_state */
memcpy(s, old_s, sizeof(BDRVSheepdogState));
g_free(old_s);
error_report("failed to open. recover old bdrv_sd_state.");
return ret;
}
static int sd_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
{
/* FIXME: Delete specified snapshot id. */
return 0;
}
static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
{
BDRVSheepdogState *s = bs->opaque;
SheepdogReq req;
int fd, nr = 1024, ret, max = BITS_TO_LONGS(SD_NR_VDIS) * sizeof(long);
QEMUSnapshotInfo *sn_tab = NULL;
unsigned wlen, rlen;
int found = 0;
static SheepdogInode inode;
unsigned long *vdi_inuse;
unsigned int start_nr;
uint64_t hval;
uint32_t vid;
vdi_inuse = g_malloc(max);
fd = connect_to_sdog(s);
if (fd < 0) {
ret = fd;
goto out;
}
rlen = max;
wlen = 0;
memset(&req, 0, sizeof(req));
req.opcode = SD_OP_READ_VDIS;
req.data_length = max;
ret = do_req(fd, (SheepdogReq *)&req, vdi_inuse, &wlen, &rlen);
closesocket(fd);
if (ret) {
goto out;
}
sn_tab = g_malloc0(nr * sizeof(*sn_tab));
/* calculate a vdi id with hash function */
hval = fnv_64a_buf(s->name, strlen(s->name), FNV1A_64_INIT);
start_nr = hval & (SD_NR_VDIS - 1);
fd = connect_to_sdog(s);
if (fd < 0) {
ret = fd;
goto out;
}
for (vid = start_nr; found < nr; vid = (vid + 1) % SD_NR_VDIS) {
if (!test_bit(vid, vdi_inuse)) {
break;
}
/* we don't need to read entire object */
ret = read_object(fd, (char *)&inode, vid_to_vdi_oid(vid),
0, SD_INODE_SIZE - sizeof(inode.data_vdi_id), 0,
s->cache_flags);
if (ret) {
continue;
}
if (!strcmp(inode.name, s->name) && is_snapshot(&inode)) {
sn_tab[found].date_sec = inode.snap_ctime >> 32;
sn_tab[found].date_nsec = inode.snap_ctime & 0xffffffff;
sn_tab[found].vm_state_size = inode.vm_state_size;
sn_tab[found].vm_clock_nsec = inode.vm_clock_nsec;
snprintf(sn_tab[found].id_str, sizeof(sn_tab[found].id_str), "%u",
inode.snap_id);
pstrcpy(sn_tab[found].name,
MIN(sizeof(sn_tab[found].name), sizeof(inode.tag)),
inode.tag);
found++;
}
}
closesocket(fd);
out:
*psn_tab = sn_tab;
g_free(vdi_inuse);
if (ret < 0) {
return ret;
}
return found;
}
static int do_load_save_vmstate(BDRVSheepdogState *s, uint8_t *data,
int64_t pos, int size, int load)
{
bool create;
int fd, ret = 0, remaining = size;
unsigned int data_len;
uint64_t vmstate_oid;
uint32_t vdi_index;
uint64_t offset;
fd = connect_to_sdog(s);
if (fd < 0) {
return fd;
}
while (remaining) {
vdi_index = pos / SD_DATA_OBJ_SIZE;
offset = pos % SD_DATA_OBJ_SIZE;
data_len = MIN(remaining, SD_DATA_OBJ_SIZE - offset);
vmstate_oid = vid_to_vmstate_oid(s->inode.vdi_id, vdi_index);
create = (offset == 0);
if (load) {
ret = read_object(fd, (char *)data, vmstate_oid,
s->inode.nr_copies, data_len, offset,
s->cache_flags);
} else {
ret = write_object(fd, (char *)data, vmstate_oid,
s->inode.nr_copies, data_len, offset, create,
s->cache_flags);
}
if (ret < 0) {
error_report("failed to save vmstate %s", strerror(errno));
goto cleanup;
}
pos += data_len;
data += data_len;
remaining -= data_len;
}
ret = size;
cleanup:
closesocket(fd);
return ret;
}
static int sd_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
int64_t pos)
{
BDRVSheepdogState *s = bs->opaque;
void *buf;
int ret;
buf = qemu_blockalign(bs, qiov->size);
qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
ret = do_load_save_vmstate(s, (uint8_t *) buf, pos, qiov->size, 0);
qemu_vfree(buf);
return ret;
}
static int sd_load_vmstate(BlockDriverState *bs, uint8_t *data,
int64_t pos, int size)
{
BDRVSheepdogState *s = bs->opaque;
return do_load_save_vmstate(s, data, pos, size, 1);
}
static coroutine_fn int sd_co_discard(BlockDriverState *bs, int64_t sector_num,
int nb_sectors)
{
SheepdogAIOCB *acb;
QEMUIOVector dummy;
BDRVSheepdogState *s = bs->opaque;
int ret;
if (!s->discard_supported) {
return 0;
}
acb = sd_aio_setup(bs, &dummy, sector_num, nb_sectors);
acb->aiocb_type = AIOCB_DISCARD_OBJ;
acb->aio_done_func = sd_finish_aiocb;
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
qemu_aio_release(acb);
return ret;
}
qemu_coroutine_yield();
return acb->ret;
}
static coroutine_fn int
sd_co_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
int *pnum)
{
BDRVSheepdogState *s = bs->opaque;
SheepdogInode *inode = &s->inode;
unsigned long start = sector_num * BDRV_SECTOR_SIZE / SD_DATA_OBJ_SIZE,
end = DIV_ROUND_UP((sector_num + nb_sectors) *
BDRV_SECTOR_SIZE, SD_DATA_OBJ_SIZE);
unsigned long idx;
int ret = 1;
for (idx = start; idx < end; idx++) {
if (inode->data_vdi_id[idx] == 0) {
break;
}
}
if (idx == start) {
/* Get the longest length of unallocated sectors */
ret = 0;
for (idx = start + 1; idx < end; idx++) {
if (inode->data_vdi_id[idx] != 0) {
break;
}
}
}
*pnum = (idx - start) * SD_DATA_OBJ_SIZE / BDRV_SECTOR_SIZE;
if (*pnum > nb_sectors) {
*pnum = nb_sectors;
}
return ret;
}
static QEMUOptionParameter sd_create_options[] = {
{
.name = BLOCK_OPT_SIZE,
.type = OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_BACKING_FILE,
.type = OPT_STRING,
.help = "File name of a base image"
},
{
.name = BLOCK_OPT_PREALLOC,
.type = OPT_STRING,
.help = "Preallocation mode (allowed values: off, full)"
},
{ NULL }
};
static BlockDriver bdrv_sheepdog = {
.format_name = "sheepdog",
.protocol_name = "sheepdog",
.instance_size = sizeof(BDRVSheepdogState),
.bdrv_file_open = sd_open,
.bdrv_close = sd_close,
.bdrv_create = sd_create,
.bdrv_getlength = sd_getlength,
.bdrv_truncate = sd_truncate,
.bdrv_co_readv = sd_co_readv,
.bdrv_co_writev = sd_co_writev,
.bdrv_co_flush_to_disk = sd_co_flush_to_disk,
.bdrv_co_discard = sd_co_discard,
.bdrv_co_is_allocated = sd_co_is_allocated,
.bdrv_snapshot_create = sd_snapshot_create,
.bdrv_snapshot_goto = sd_snapshot_goto,
.bdrv_snapshot_delete = sd_snapshot_delete,
.bdrv_snapshot_list = sd_snapshot_list,
.bdrv_save_vmstate = sd_save_vmstate,
.bdrv_load_vmstate = sd_load_vmstate,
.create_options = sd_create_options,
};
static BlockDriver bdrv_sheepdog_tcp = {
.format_name = "sheepdog",
.protocol_name = "sheepdog+tcp",
.instance_size = sizeof(BDRVSheepdogState),
.bdrv_file_open = sd_open,
.bdrv_close = sd_close,
.bdrv_create = sd_create,
.bdrv_getlength = sd_getlength,
.bdrv_truncate = sd_truncate,
.bdrv_co_readv = sd_co_readv,
.bdrv_co_writev = sd_co_writev,
.bdrv_co_flush_to_disk = sd_co_flush_to_disk,
.bdrv_co_discard = sd_co_discard,
.bdrv_co_is_allocated = sd_co_is_allocated,
.bdrv_snapshot_create = sd_snapshot_create,
.bdrv_snapshot_goto = sd_snapshot_goto,
.bdrv_snapshot_delete = sd_snapshot_delete,
.bdrv_snapshot_list = sd_snapshot_list,
.bdrv_save_vmstate = sd_save_vmstate,
.bdrv_load_vmstate = sd_load_vmstate,
.create_options = sd_create_options,
};
static BlockDriver bdrv_sheepdog_unix = {
.format_name = "sheepdog",
.protocol_name = "sheepdog+unix",
.instance_size = sizeof(BDRVSheepdogState),
.bdrv_file_open = sd_open,
.bdrv_close = sd_close,
.bdrv_create = sd_create,
.bdrv_getlength = sd_getlength,
.bdrv_truncate = sd_truncate,
.bdrv_co_readv = sd_co_readv,
.bdrv_co_writev = sd_co_writev,
.bdrv_co_flush_to_disk = sd_co_flush_to_disk,
.bdrv_co_discard = sd_co_discard,
.bdrv_co_is_allocated = sd_co_is_allocated,
.bdrv_snapshot_create = sd_snapshot_create,
.bdrv_snapshot_goto = sd_snapshot_goto,
.bdrv_snapshot_delete = sd_snapshot_delete,
.bdrv_snapshot_list = sd_snapshot_list,
.bdrv_save_vmstate = sd_save_vmstate,
.bdrv_load_vmstate = sd_load_vmstate,
.create_options = sd_create_options,
};
static void bdrv_sheepdog_init(void)
{
bdrv_register(&bdrv_sheepdog);
bdrv_register(&bdrv_sheepdog_tcp);
bdrv_register(&bdrv_sheepdog_unix);
}
block_init(bdrv_sheepdog_init);