block: Drop the sheepdog block driver

It was deprecated in commit e1c4269763, v5.2.0.  See that commit
message for rationale.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210501075747.3293186-1-armbru@redhat.com>
ACKed-by: Peter Krempa <pkrempa@redhat.com>

17 files changed, 14 insertions, 3593 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index da65707..745fdae 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -342,7 +342,6 @@ build-disabled:
       --disable-replication
       --disable-sdl
       --disable-seccomp
-      --disable-sheepdog
       --disable-slirp
       --disable-smartcard
       --disable-snappy
diff --git a/MAINTAINERS b/MAINTAINERS
index 50884fe..c765165 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3072,12 +3072,6 @@ L: qemu-block@nongnu.org
 S: Supported
 F: block/rbd.c
 
-Sheepdog
-M: Liu Yuan <namei.unix@gmail.com>
-L: qemu-block@nongnu.org
-S: Odd Fixes
-F: block/sheepdog.c
-
 VHDX
 M: Jeff Cody <codyprime@gmail.com>
 L: qemu-block@nongnu.org
diff --git a/block/meson.build b/block/meson.build
index d21990e..e687c54 100644
--- a/block/meson.build
+++ b/block/meson.build
@@ -64,7 +64,6 @@ block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref, iokit
 block_ss.add(when: libiscsi, if_true: files('iscsi-opts.c'))
 block_ss.add(when: 'CONFIG_LINUX', if_true: files('nvme.c'))
 block_ss.add(when: 'CONFIG_REPLICATION', if_true: files('replication.c'))
-block_ss.add(when: 'CONFIG_SHEEPDOG', if_true: files('sheepdog.c'))
 block_ss.add(when: ['CONFIG_LINUX_AIO', libaio], if_true: files('linux-aio.c'))
 block_ss.add(when: ['CONFIG_LINUX_IO_URING', linux_io_uring], if_true: files('io_uring.c'))
 
diff --git a/block/sheepdog.c b/block/sheepdog.c
deleted file mode 100644
index a45c738..0000000
--- a/block/sheepdog.c
+++ /dev/null
@@ -1,3356 +0,0 @@
-/*
- * 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/osdep.h"
-#include "qemu-common.h"
-#include "qapi/error.h"
-#include "qapi/qapi-visit-sockets.h"
-#include "qapi/qapi-visit-block-core.h"
-#include "qapi/qmp/qdict.h"
-#include "qapi/qobject-input-visitor.h"
-#include "qapi/qobject-output-visitor.h"
-#include "qemu/uri.h"
-#include "qemu/error-report.h"
-#include "qemu/main-loop.h"
-#include "qemu/module.h"
-#include "qemu/option.h"
-#include "qemu/sockets.h"
-#include "block/block_int.h"
-#include "block/qdict.h"
-#include "sysemu/block-backend.h"
-#include "qemu/bitops.h"
-#include "qemu/cutils.h"
-#include "trace.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_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_OP_GET_CLUSTER_DEFAULT   0x18
-
-#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_DEFAULT_BLOCK_SIZE_SHIFT 22
-/*
- * For erasure coding, we use at most SD_EC_MAX_STRIP for data strips and
- * (SD_EC_MAX_STRIP - 1) for parity strips
- *
- * SD_MAX_COPIES is sum of number of data strips and parity strips.
- */
-#define SD_EC_MAX_STRIP 16
-#define SD_MAX_COPIES (SD_EC_MAX_STRIP * 2 - 1)
-
-#define SD_INODE_SIZE (sizeof(SheepdogInode))
-#define CURRENT_VDI_ID 0
-
-#define LOCK_TYPE_NORMAL 0
-#define LOCK_TYPE_SHARED 1      /* for iSCSI multipath */
-
-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;
-    uint8_t copies;
-    uint8_t copy_policy;
-    uint8_t reserved[6];
-    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;
-    uint8_t copies;
-    uint8_t copy_policy;
-    uint8_t reserved[2];
-    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 base_vdi_id;
-    uint8_t copies;
-    uint8_t copy_policy;
-    uint8_t store_policy;
-    uint8_t block_size_shift;
-    uint32_t snapid;
-    uint32_t type;
-    uint32_t pad[2];
-} 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 SheepdogClusterRsp {
-    uint8_t proto_ver;
-    uint8_t opcode;
-    uint16_t flags;
-    uint32_t epoch;
-    uint32_t id;
-    uint32_t data_length;
-    uint32_t result;
-    uint8_t nr_copies;
-    uint8_t copy_policy;
-    uint8_t block_size_shift;
-    uint8_t __pad1;
-    uint32_t __pad2[6];
-} SheepdogClusterRsp;
-
-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;
-
-#define SD_INODE_HEADER_SIZE offsetof(SheepdogInode, data_vdi_id)
-
-/*
- * 64 bit FNV-1a non-zero initial basis
- */
-#define FNV1A_64_INIT ((uint64_t)0xcbf29ce484222325ULL)
-
-static void deprecation_warning(void)
-{
-    static bool warned;
-
-    if (!warned) {
-        warn_report("the sheepdog block driver is deprecated");
-        warned = true;
-    }
-}
-
-/*
- * 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 uint32_t oid_to_vid(uint64_t oid)
-{
-    return (oid & ~VDI_BIT) >> VDI_SPACE_SHIFT;
-}
-
-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;
-}
-
-static inline size_t count_data_objs(const struct SheepdogInode *inode)
-{
-    return DIV_ROUND_UP(inode->vdi_size,
-                        (1UL << inode->block_size_shift));
-}
-
-typedef struct SheepdogAIOCB SheepdogAIOCB;
-typedef struct BDRVSheepdogState BDRVSheepdogState;
-
-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;
-    bool create;
-
-    QLIST_ENTRY(AIOReq) aio_siblings;
-} AIOReq;
-
-enum AIOCBState {
-    AIOCB_WRITE_UDATA,
-    AIOCB_READ_UDATA,
-    AIOCB_FLUSH_CACHE,
-    AIOCB_DISCARD_OBJ,
-};
-
-#define AIOCBOverlapping(x, y)                                 \
-    (!(x->max_affect_data_idx < y->min_affect_data_idx          \
-       || y->max_affect_data_idx < x->min_affect_data_idx))
-
-struct SheepdogAIOCB {
-    BDRVSheepdogState *s;
-
-    QEMUIOVector *qiov;
-
-    int64_t sector_num;
-    int nb_sectors;
-
-    int ret;
-    enum AIOCBState aiocb_type;
-
-    Coroutine *coroutine;
-    int nr_pending;
-
-    uint32_t min_affect_data_idx;
-    uint32_t max_affect_data_idx;
-
-    /*
-     * The difference between affect_data_idx and dirty_data_idx:
-     * affect_data_idx represents range of index of all request types.
-     * dirty_data_idx represents range of index updated by COW requests.
-     * dirty_data_idx is used for updating an inode object.
-     */
-    uint32_t min_dirty_data_idx;
-    uint32_t max_dirty_data_idx;
-
-    QLIST_ENTRY(SheepdogAIOCB) aiocb_siblings;
-};
-
-struct BDRVSheepdogState {
-    BlockDriverState *bs;
-    AioContext *aio_context;
-
-    SheepdogInode inode;
-
-    char name[SD_MAX_VDI_LEN];
-    bool is_snapshot;
-    uint32_t cache_flags;
-    bool discard_supported;
-
-    SocketAddress *addr;
-    int fd;
-
-    CoMutex lock;
-    Coroutine *co_send;
-    Coroutine *co_recv;
-
-    uint32_t aioreq_seq_num;
-
-    /* Every aio request must be linked to either of these queues. */
-    QLIST_HEAD(, AIOReq) inflight_aio_head;
-    QLIST_HEAD(, AIOReq) failed_aio_head;
-
-    CoMutex queue_lock;
-    CoQueue overlapping_queue;
-    QLIST_HEAD(, SheepdogAIOCB) inflight_aiocb_head;
-};
-
-typedef struct BDRVSheepdogReopenState {
-    int fd;
-    int cache_flags;
-} BDRVSheepdogReopenState;
-
-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 yields while waiting for
- *    receiving the response.
- *
- * 2. We receive the response in aio_read_response, the fd handler to
- *    the sheepdog connection.  We switch back to sd_co_readv/sd_writev
- *    after all the requests belonging to the AIOCB are finished.  If
- *    needed, sd_co_writev will send another requests for the vdi object.
- */
-
-static inline AIOReq *alloc_aio_req(BDRVSheepdogState *s, SheepdogAIOCB *acb,
-                                    uint64_t oid, unsigned int data_len,
-                                    uint64_t offset, uint8_t flags, bool create,
-                                    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++;
-    aio_req->create = create;
-
-    acb->nr_pending++;
-    return aio_req;
-}
-
-static void wait_for_overlapping_aiocb(BDRVSheepdogState *s, SheepdogAIOCB *acb)
-{
-    SheepdogAIOCB *cb;
-
-retry:
-    QLIST_FOREACH(cb, &s->inflight_aiocb_head, aiocb_siblings) {
-        if (AIOCBOverlapping(acb, cb)) {
-            qemu_co_queue_wait(&s->overlapping_queue, &s->queue_lock);
-            goto retry;
-        }
-    }
-}
-
-static void sd_aio_setup(SheepdogAIOCB *acb, BDRVSheepdogState *s,
-                         QEMUIOVector *qiov, int64_t sector_num, int nb_sectors,
-                         int type)
-{
-    uint32_t object_size;
-
-    object_size = (UINT32_C(1) << s->inode.block_size_shift);
-
-    acb->s = s;
-
-    acb->qiov = qiov;
-
-    acb->sector_num = sector_num;
-    acb->nb_sectors = nb_sectors;
-
-    acb->coroutine = qemu_coroutine_self();
-    acb->ret = 0;
-    acb->nr_pending = 0;
-
-    acb->min_affect_data_idx = acb->sector_num * BDRV_SECTOR_SIZE / object_size;
-    acb->max_affect_data_idx = (acb->sector_num * BDRV_SECTOR_SIZE +
-                              acb->nb_sectors * BDRV_SECTOR_SIZE) / object_size;
-
-    acb->min_dirty_data_idx = UINT32_MAX;
-    acb->max_dirty_data_idx = 0;
-    acb->aiocb_type = type;
-
-    if (type == AIOCB_FLUSH_CACHE) {
-        return;
-    }
-
-    qemu_co_mutex_lock(&s->queue_lock);
-    wait_for_overlapping_aiocb(s, acb);
-    QLIST_INSERT_HEAD(&s->inflight_aiocb_head, acb, aiocb_siblings);
-    qemu_co_mutex_unlock(&s->queue_lock);
-}
-
-static SocketAddress *sd_server_config(QDict *options, Error **errp)
-{
-    QDict *server = NULL;
-    Visitor *iv = NULL;
-    SocketAddress *saddr = NULL;
-
-    qdict_extract_subqdict(options, &server, "server.");
-
-    iv = qobject_input_visitor_new_flat_confused(server, errp);
-    if (!iv) {
-        goto done;
-    }
-
-    if (!visit_type_SocketAddress(iv, NULL, &saddr, errp)) {
-        goto done;
-    }
-
-done:
-    visit_free(iv);
-    qobject_unref(server);
-    return saddr;
-}
-
-/* Return -EIO in case of error, file descriptor on success */
-static int connect_to_sdog(BDRVSheepdogState *s, Error **errp)
-{
-    int fd;
-
-    fd = socket_connect(s->addr, errp);
-
-    if (s->addr->type == SOCKET_ADDRESS_TYPE_INET && fd >= 0) {
-        int ret = socket_set_nodelay(fd);
-        if (ret < 0) {
-            warn_report("can't set TCP_NODELAY: %s", strerror(errno));
-        }
-    }
-
-    if (fd >= 0) {
-        qemu_set_nonblock(fd);
-    } else {
-        fd = -EIO;
-    }
-
-    return fd;
-}
-
-/* Return 0 on success and -errno in case of error */
-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 -errno;
-    }
-
-    ret = qemu_co_send(sockfd, data, *wlen);
-    if (ret != *wlen) {
-        error_report("failed to send a req, %s", strerror(errno));
-        return -errno;
-    }
-
-    return ret;
-}
-
-typedef struct SheepdogReqCo {
-    int sockfd;
-    BlockDriverState *bs;
-    AioContext *aio_context;
-    SheepdogReq *hdr;
-    void *data;
-    unsigned int *wlen;
-    unsigned int *rlen;
-    int ret;
-    bool finished;
-    Coroutine *co;
-} SheepdogReqCo;
-
-static void restart_co_req(void *opaque)
-{
-    SheepdogReqCo *srco = opaque;
-
-    aio_co_wake(srco->co);
-}
-
-static coroutine_fn void do_co_req(void *opaque)
-{
-    int ret;
-    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;
-
-    srco->co = qemu_coroutine_self();
-    aio_set_fd_handler(srco->aio_context, sockfd, false,
-                       NULL, restart_co_req, NULL, srco);
-
-    ret = send_co_req(sockfd, hdr, data, wlen);
-    if (ret < 0) {
-        goto out;
-    }
-
-    aio_set_fd_handler(srco->aio_context, sockfd, false,
-                       restart_co_req, NULL, NULL, srco);
-
-    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. */
-    aio_set_fd_handler(srco->aio_context, sockfd, false,
-                       NULL, NULL, NULL, NULL);
-
-    srco->co = NULL;
-    srco->ret = ret;
-    /* Set srco->finished before reading bs->wakeup.  */
-    qatomic_mb_set(&srco->finished, true);
-    if (srco->bs) {
-        bdrv_wakeup(srco->bs);
-    }
-}
-
-/*
- * Send the request to the sheep in a synchronous manner.
- *
- * Return 0 on success, -errno in case of error.
- */
-static int do_req(int sockfd, BlockDriverState *bs, SheepdogReq *hdr,
-                  void *data, unsigned int *wlen, unsigned int *rlen)
-{
-    Coroutine *co;
-    SheepdogReqCo srco = {
-        .sockfd = sockfd,
-        .aio_context = bs ? bdrv_get_aio_context(bs) : qemu_get_aio_context(),
-        .bs = bs,
-        .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, &srco);
-        if (bs) {
-            bdrv_coroutine_enter(bs, co);
-            BDRV_POLL_WHILE(bs, !srco.finished);
-        } else {
-            qemu_coroutine_enter(co);
-            while (!srco.finished) {
-                aio_poll(qemu_get_aio_context(), true);
-            }
-        }
-    }
-
-    return srco.ret;
-}
-
-static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
-                                         struct iovec *iov, int niov,
-                                         enum AIOCBState aiocb_type);
-static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req);
-static int reload_inode(BDRVSheepdogState *s, uint32_t snapid, const char *tag);
-static int get_sheep_fd(BDRVSheepdogState *s, Error **errp);
-static void co_write_request(void *opaque);
-
-static coroutine_fn void reconnect_to_sdog(void *opaque)
-{
-    BDRVSheepdogState *s = opaque;
-    AIOReq *aio_req, *next;
-
-    aio_set_fd_handler(s->aio_context, s->fd, false, NULL,
-                       NULL, NULL, NULL);
-    close(s->fd);
-    s->fd = -1;
-
-    /* Wait for outstanding write requests to be completed. */
-    while (s->co_send != NULL) {
-        co_write_request(opaque);
-    }
-
-    /* Try to reconnect the sheepdog server every one second. */
-    while (s->fd < 0) {
-        Error *local_err = NULL;
-        s->fd = get_sheep_fd(s, &local_err);
-        if (s->fd < 0) {
-            trace_sheepdog_reconnect_to_sdog();
-            error_report_err(local_err);
-            qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, NANOSECONDS_PER_SECOND);
-        }
-    };
-
-    /*
-     * Now we have to resend all the request in the inflight queue.  However,
-     * resend_aioreq() can yield and newly created requests can be added to the
-     * inflight queue before the coroutine is resumed.  To avoid mixing them, we
-     * have to move all the inflight requests to the failed queue before
-     * resend_aioreq() is called.
-     */
-    qemu_co_mutex_lock(&s->queue_lock);
-    QLIST_FOREACH_SAFE(aio_req, &s->inflight_aio_head, aio_siblings, next) {
-        QLIST_REMOVE(aio_req, aio_siblings);
-        QLIST_INSERT_HEAD(&s->failed_aio_head, aio_req, aio_siblings);
-    }
-
-    /* Resend all the failed aio requests. */
-    while (!QLIST_EMPTY(&s->failed_aio_head)) {
-        aio_req = QLIST_FIRST(&s->failed_aio_head);
-        QLIST_REMOVE(aio_req, aio_siblings);
-        qemu_co_mutex_unlock(&s->queue_lock);
-        resend_aioreq(s, aio_req);
-        qemu_co_mutex_lock(&s->queue_lock);
-    }
-    qemu_co_mutex_unlock(&s->queue_lock);
-}
-
-/*
- * 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;
-
-    /* read a header */
-    ret = qemu_co_recv(fd, &rsp, sizeof(rsp));
-    if (ret != sizeof(rsp)) {
-        error_report("failed to get the header, %s", strerror(errno));
-        goto err;
-    }
-
-    /* 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 err;
-    }
-
-    acb = aio_req->aiocb;
-
-    switch (acb->aiocb_type) {
-    case AIOCB_WRITE_UDATA:
-        if (!is_data_obj(aio_req->oid)) {
-            break;
-        }
-        idx = data_oid_to_idx(aio_req->oid);
-
-        if (aio_req->create) {
-            /*
-             * 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;
-                acb->max_dirty_data_idx = MAX(idx, acb->max_dirty_data_idx);
-                acb->min_dirty_data_idx = MIN(idx, acb->min_dirty_data_idx);
-            }
-        }
-        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 != rsp.data_length) {
-            error_report("failed to get the data, %s", strerror(errno));
-            goto err;
-        }
-        break;
-    case AIOCB_FLUSH_CACHE:
-        if (rsp.result == SD_RES_INVALID_PARMS) {
-            trace_sheepdog_aio_read_response();
-            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("server doesn't support discard command");
-            rsp.result = SD_RES_SUCCESS;
-            s->discard_supported = false;
-            break;
-        default:
-            break;
-        }
-    }
-
-    /* No more data for this aio_req (reload_inode below uses its own file
-     * descriptor handler which doesn't use co_recv).
-    */
-    s->co_recv = NULL;
-
-    qemu_co_mutex_lock(&s->queue_lock);
-    QLIST_REMOVE(aio_req, aio_siblings);
-    qemu_co_mutex_unlock(&s->queue_lock);
-
-    switch (rsp.result) {
-    case SD_RES_SUCCESS:
-        break;
-    case SD_RES_READONLY:
-        if (s->inode.vdi_id == oid_to_vid(aio_req->oid)) {
-            ret = reload_inode(s, 0, "");
-            if (ret < 0) {
-                goto err;
-            }
-        }
-        if (is_data_obj(aio_req->oid)) {
-            aio_req->oid = vid_to_data_oid(s->inode.vdi_id,
-                                           data_oid_to_idx(aio_req->oid));
-        } else {
-            aio_req->oid = vid_to_vdi_oid(s->inode.vdi_id);
-        }
-        resend_aioreq(s, aio_req);
-        return;
-    default:
-        acb->ret = -EIO;
-        error_report("%s", sd_strerror(rsp.result));
-        break;
-    }
-
-    g_free(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.
-         */
-        aio_co_wake(acb->coroutine);
-    }
-
-    return;
-
-err:
-    reconnect_to_sdog(opaque);
-}
-
-static void co_read_response(void *opaque)
-{
-    BDRVSheepdogState *s = opaque;
-
-    if (!s->co_recv) {
-        s->co_recv = qemu_coroutine_create(aio_read_response, opaque);
-    }
-
-    aio_co_enter(s->aio_context, s->co_recv);
-}
-
-static void co_write_request(void *opaque)
-{
-    BDRVSheepdogState *s = opaque;
-
-    aio_co_wake(s->co_send);
-}
-
-/*
- * Return a socket descriptor to read/write objects.
- *
- * We cannot use this descriptor for other operations because
- * the block driver may be on waiting response from the server.
- */
-static int get_sheep_fd(BDRVSheepdogState *s, Error **errp)
-{
-    int fd;
-
-    fd = connect_to_sdog(s, errp);
-    if (fd < 0) {
-        return fd;
-    }
-
-    aio_set_fd_handler(s->aio_context, fd, false,
-                       co_read_response, NULL, NULL, s);
-    return fd;
-}
-
-/*
- * Parse numeric snapshot ID in @str
- * If @str can't be parsed as number, return false.
- * Else, if the number is zero or too large, set *@snapid to zero and
- * return true.
- * Else, set *@snapid to the number and return true.
- */
-static bool sd_parse_snapid(const char *str, uint32_t *snapid)
-{
-    unsigned long ul;
-    int ret;
-
-    ret = qemu_strtoul(str, NULL, 10, &ul);
-    if (ret == -ERANGE) {
-        ul = ret = 0;
-    }
-    if (ret) {
-        return false;
-    }
-    if (ul > UINT32_MAX) {
-        ul = 0;
-    }
-
-    *snapid = ul;
-    return true;
-}
-
-static bool sd_parse_snapid_or_tag(const char *str,
-                                   uint32_t *snapid, char tag[])
-{
-    if (!sd_parse_snapid(str, snapid)) {
-        *snapid = 0;
-        if (g_strlcpy(tag, str, SD_MAX_VDI_TAG_LEN) >= SD_MAX_VDI_TAG_LEN) {
-            return false;
-        }
-    } else if (!*snapid) {
-        return false;
-    } else {
-        tag[0] = 0;
-    }
-    return true;
-}
-
-typedef struct {
-    const char *path;           /* non-null iff transport is tcp */
-    const char *host;           /* valid when transport is tcp */
-    int port;                   /* valid when transport is tcp */
-    char vdi[SD_MAX_VDI_LEN];
-    char tag[SD_MAX_VDI_TAG_LEN];
-    uint32_t snap_id;
-    /* Remainder is only for sd_config_done() */
-    URI *uri;
-    QueryParams *qp;
-} SheepdogConfig;
-
-static void sd_config_done(SheepdogConfig *cfg)
-{
-    if (cfg->qp) {
-        query_params_free(cfg->qp);
-    }
-    uri_free(cfg->uri);
-}
-
-static void sd_parse_uri(SheepdogConfig *cfg, const char *filename,
-                         Error **errp)
-{
-    Error *err = NULL;
-    QueryParams *qp = NULL;
-    bool is_unix;
-    URI *uri;
-
-    memset(cfg, 0, sizeof(*cfg));
-
-    cfg->uri = uri = uri_parse(filename);
-    if (!uri) {
-        error_setg(&err, "invalid URI '%s'", filename);
-        goto out;
-    }
-
-    /* transport */
-    if (!g_strcmp0(uri->scheme, "sheepdog")) {
-        is_unix = false;
-    } else if (!g_strcmp0(uri->scheme, "sheepdog+tcp")) {
-        is_unix = false;
-    } else if (!g_strcmp0(uri->scheme, "sheepdog+unix")) {
-        is_unix = true;
-    } else {
-        error_setg(&err, "URI scheme must be 'sheepdog', 'sheepdog+tcp',"
-                   " or 'sheepdog+unix'");
-        goto out;
-    }
-
-    if (uri->path == NULL || !strcmp(uri->path, "/")) {
-        error_setg(&err, "missing file path in URI");
-        goto out;
-    }
-    if (g_strlcpy(cfg->vdi, uri->path + 1, SD_MAX_VDI_LEN)
-        >= SD_MAX_VDI_LEN) {
-        error_setg(&err, "VDI name is too long");
-        goto out;
-    }
-
-    cfg->qp = qp = query_params_parse(uri->query);
-
-    if (is_unix) {
-        /* sheepdog+unix:///vdiname?socket=path */
-        if (uri->server || uri->port) {
-            error_setg(&err, "URI scheme %s doesn't accept a server address",
-                       uri->scheme);
-            goto out;
-        }
-        if (!qp->n) {
-            error_setg(&err,
-                       "URI scheme %s requires query parameter 'socket'",
-                       uri->scheme);
-            goto out;
-        }
-        if (qp->n != 1 || strcmp(qp->p[0].name, "socket")) {
-            error_setg(&err, "unexpected query parameters");
-            goto out;
-        }
-        cfg->path = qp->p[0].value;
-    } else {
-        /* sheepdog[+tcp]://[host:port]/vdiname */
-        if (qp->n) {
-            error_setg(&err, "unexpected query parameters");
-            goto out;
-        }
-        cfg->host = uri->server;
-        cfg->port = uri->port;
-    }
-
-    /* snapshot tag */
-    if (uri->fragment) {
-        if (!sd_parse_snapid_or_tag(uri->fragment,
-                                    &cfg->snap_id, cfg->tag)) {
-            error_setg(&err, "'%s' is not a valid snapshot ID",
-                       uri->fragment);
-            goto out;
-        }
-    } else {
-        cfg->snap_id = CURRENT_VDI_ID; /* search current vdi */
-    }
-
-out:
-    if (err) {
-        error_propagate(errp, err);
-        sd_config_done(cfg);
-    }
-}
-
-/*
- * 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 void parse_vdiname(SheepdogConfig *cfg, const char *filename,
-                          Error **errp)
-{
-    Error *err = NULL;
-    char *p, *q, *uri;
-    const char *host_spec, *vdi_spec;
-    int nr_sep;
-
-    strstart(filename, "sheepdog:", &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);
-
-    /*
-     * FIXME We to escape URI meta-characters, e.g. "x?y=z"
-     * produces "sheepdog://x?y=z".  Because of that ...
-     */
-    sd_parse_uri(cfg, uri, &err);
-    if (err) {
-        /*
-         * ... this can fail, but the error message is misleading.
-         * Replace it by the traditional useless one until the
-         * escaping is fixed.
-         */
-        error_free(err);
-        error_setg(errp, "Can't parse filename");
-    }
-
-    g_free(q);
-    g_free(uri);
-}
-
-static void sd_parse_filename(const char *filename, QDict *options,
-                              Error **errp)
-{
-    Error *err = NULL;
-    SheepdogConfig cfg;
-    char buf[32];
-
-    if (strstr(filename, "://")) {
-        sd_parse_uri(&cfg, filename, &err);
-    } else {
-        parse_vdiname(&cfg, filename, &err);
-    }
-    if (err) {
-        error_propagate(errp, err);
-        return;
-    }
-
-    if (cfg.path) {
-        qdict_set_default_str(options, "server.path", cfg.path);
-        qdict_set_default_str(options, "server.type", "unix");
-    } else {
-        qdict_set_default_str(options, "server.type", "inet");
-        qdict_set_default_str(options, "server.host",
-                              cfg.host ?: SD_DEFAULT_ADDR);
-        snprintf(buf, sizeof(buf), "%d", cfg.port ?: SD_DEFAULT_PORT);
-        qdict_set_default_str(options, "server.port", buf);
-    }
-    qdict_set_default_str(options, "vdi", cfg.vdi);
-    qdict_set_default_str(options, "tag", cfg.tag);
-    if (cfg.snap_id) {
-        snprintf(buf, sizeof(buf), "%d", cfg.snap_id);
-        qdict_set_default_str(options, "snap-id", buf);
-    }
-
-    sd_config_done(&cfg);
-}
-
-static int find_vdi_name(BDRVSheepdogState *s, const char *filename,
-                         uint32_t snapid, const char *tag, uint32_t *vid,
-                         bool lock, Error **errp)
-{
-    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] QEMU_NONSTRING;
-
-    fd = connect_to_sdog(s, errp);
-    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;
-        hdr.type = LOCK_TYPE_NORMAL;
-    } 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, s->bs, (SheepdogReq *)&hdr, buf, &wlen, &rlen);
-    if (ret) {
-        error_setg_errno(errp, -ret, "cannot get vdi info");
-        goto out;
-    }
-
-    if (rsp->result != SD_RES_SUCCESS) {
-        error_setg(errp, "cannot get vdi info, %s, %s %" PRIu32 " %s",
-                   sd_strerror(rsp->result), filename, snapid, tag);
-        if (rsp->result == SD_RES_NO_VDI) {
-            ret = -ENOENT;
-        } else if (rsp->result == SD_RES_VDI_LOCKED) {
-            ret = -EBUSY;
-        } else {
-            ret = -EIO;
-        }
-        goto out;
-    }
-    *vid = rsp->vdi_id;
-
-    ret = 0;
-out:
-    closesocket(fd);
-    return ret;
-}
-
-static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
-                                         struct iovec *iov, int niov,
-                                         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;
-    bool create = aio_req->create;
-
-    qemu_co_mutex_lock(&s->queue_lock);
-    QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
-    qemu_co_mutex_unlock(&s->queue_lock);
-
-    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_WRITE_OBJ;
-        hdr.flags = SD_FLAG_CMD_WRITE | flags;
-        s->inode.data_vdi_id[data_oid_to_idx(oid)] = 0;
-        offset = offsetof(SheepdogInode,
-                          data_vdi_id[data_oid_to_idx(oid)]);
-        oid = vid_to_vdi_oid(s->inode.vdi_id);
-        wlen = datalen = sizeof(uint32_t);
-        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();
-    aio_set_fd_handler(s->aio_context, s->fd, false,
-                       co_read_response, co_write_request, NULL, s);
-    socket_set_cork(s->fd, 1);
-
-    /* send a header */
-    ret = qemu_co_send(s->fd, &hdr, sizeof(hdr));
-    if (ret != sizeof(hdr)) {
-        error_report("failed to send a req, %s", strerror(errno));
-        goto out;
-    }
-
-    if (wlen) {
-        ret = qemu_co_sendv(s->fd, iov, niov, aio_req->iov_offset, wlen);
-        if (ret != wlen) {
-            error_report("failed to send a data, %s", strerror(errno));
-        }
-    }
-out:
-    socket_set_cork(s->fd, 0);
-    aio_set_fd_handler(s->aio_context, s->fd, false,
-                       co_read_response, NULL, NULL, s);
-    s->co_send = NULL;
-    qemu_co_mutex_unlock(&s->lock);
-}
-
-static int read_write_object(int fd, BlockDriverState *bs, char *buf,
-                             uint64_t oid, uint8_t 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, bs, (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, BlockDriverState *bs, char *buf,
-                       uint64_t oid, uint8_t copies,
-                       unsigned int datalen, uint64_t offset,
-                       uint32_t cache_flags)
-{
-    return read_write_object(fd, bs, buf, oid, copies,
-                             datalen, offset, false,
-                             false, cache_flags);
-}
-
-static int write_object(int fd, BlockDriverState *bs, char *buf,
-                        uint64_t oid, uint8_t copies,
-                        unsigned int datalen, uint64_t offset, bool create,
-                        uint32_t cache_flags)
-{
-    return read_write_object(fd, bs, 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)
-{
-    Error *local_err = NULL;
-    SheepdogInode *inode;
-    int ret = 0, fd;
-    uint32_t vid = 0;
-
-    fd = connect_to_sdog(s, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        return -EIO;
-    }
-
-    inode = g_malloc(SD_INODE_HEADER_SIZE);
-
-    ret = find_vdi_name(s, s->name, snapid, tag, &vid, false, &local_err);
-    if (ret) {
-        error_report_err(local_err);
-        goto out;
-    }
-
-    ret = read_object(fd, s->bs, (char *)inode, vid_to_vdi_oid(vid),
-                      s->inode.nr_copies, SD_INODE_HEADER_SIZE, 0,
-                      s->cache_flags);
-    if (ret < 0) {
-        goto out;
-    }
-
-    if (inode->vdi_id != s->inode.vdi_id) {
-        memcpy(&s->inode, inode, SD_INODE_HEADER_SIZE);
-    }
-
-out:
-    g_free(inode);
-    closesocket(fd);
-
-    return ret;
-}
-
-static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req)
-{
-    SheepdogAIOCB *acb = aio_req->aiocb;
-
-    aio_req->create = false;
-
-    /* check whether this request becomes a CoW one */
-    if (acb->aiocb_type == AIOCB_WRITE_UDATA && is_data_obj(aio_req->oid)) {
-        int idx = data_oid_to_idx(aio_req->oid);
-
-        if (is_data_obj_writable(&s->inode, idx)) {
-            goto out;
-        }
-
-        if (s->inode.data_vdi_id[idx]) {
-            aio_req->base_oid = vid_to_data_oid(s->inode.data_vdi_id[idx], idx);
-            aio_req->flags |= SD_FLAG_CMD_COW;
-        }
-        aio_req->create = true;
-    }
-out:
-    if (is_data_obj(aio_req->oid)) {
-        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
-                        acb->aiocb_type);
-    } else {
-        struct iovec iov;
-        iov.iov_base = &s->inode;
-        iov.iov_len = sizeof(s->inode);
-        add_aio_request(s, aio_req, &iov, 1, AIOCB_WRITE_UDATA);
-    }
-}
-
-static void sd_detach_aio_context(BlockDriverState *bs)
-{
-    BDRVSheepdogState *s = bs->opaque;
-
-    aio_set_fd_handler(s->aio_context, s->fd, false, NULL,
-                       NULL, NULL, NULL);
-}
-
-static void sd_attach_aio_context(BlockDriverState *bs,
-                                  AioContext *new_context)
-{
-    BDRVSheepdogState *s = bs->opaque;
-
-    s->aio_context = new_context;
-    aio_set_fd_handler(new_context, s->fd, false,
-                       co_read_response, NULL, NULL, s);
-}
-
-static QemuOptsList runtime_opts = {
-    .name = "sheepdog",
-    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
-    .desc = {
-        {
-            .name = "vdi",
-            .type = QEMU_OPT_STRING,
-        },
-        {
-            .name = "snap-id",
-            .type = QEMU_OPT_NUMBER,
-        },
-        {
-            .name = "tag",
-            .type = QEMU_OPT_STRING,
-        },
-        { /* end of list */ }
-    },
-};
-
-static int sd_open(BlockDriverState *bs, QDict *options, int flags,
-                   Error **errp)
-{
-    int ret, fd;
-    uint32_t vid = 0;
-    BDRVSheepdogState *s = bs->opaque;
-    const char *vdi, *snap_id_str, *tag;
-    uint64_t snap_id;
-    char *buf = NULL;
-    QemuOpts *opts;
-
-    deprecation_warning();
-
-    s->bs = bs;
-    s->aio_context = bdrv_get_aio_context(bs);
-
-    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
-    if (!qemu_opts_absorb_qdict(opts, options, errp)) {
-        ret = -EINVAL;
-        goto err_no_fd;
-    }
-
-    s->addr = sd_server_config(options, errp);
-    if (!s->addr) {
-        ret = -EINVAL;
-        goto err_no_fd;
-    }
-
-    vdi = qemu_opt_get(opts, "vdi");
-    snap_id_str = qemu_opt_get(opts, "snap-id");
-    snap_id = qemu_opt_get_number(opts, "snap-id", CURRENT_VDI_ID);
-    tag = qemu_opt_get(opts, "tag");
-
-    if (!vdi) {
-        error_setg(errp, "parameter 'vdi' is missing");
-        ret = -EINVAL;
-        goto err_no_fd;
-    }
-    if (strlen(vdi) >= SD_MAX_VDI_LEN) {
-        error_setg(errp, "value of parameter 'vdi' is too long");
-        ret = -EINVAL;
-        goto err_no_fd;
-    }
-
-    if (snap_id > UINT32_MAX) {
-        snap_id = 0;
-    }
-    if (snap_id_str && !snap_id) {
-        error_setg(errp, "'snap-id=%s' is not a valid snapshot ID",
-                   snap_id_str);
-        ret = -EINVAL;
-        goto err_no_fd;
-    }
-
-    if (!tag) {
-        tag = "";
-    }
-    if (strlen(tag) >= SD_MAX_VDI_TAG_LEN) {
-        error_setg(errp, "value of parameter 'tag' is too long");
-        ret = -EINVAL;
-        goto err_no_fd;
-    }
-
-    QLIST_INIT(&s->inflight_aio_head);
-    QLIST_INIT(&s->failed_aio_head);
-    QLIST_INIT(&s->inflight_aiocb_head);
-
-    s->fd = get_sheep_fd(s, errp);
-    if (s->fd < 0) {
-        ret = s->fd;
-        goto err_no_fd;
-    }
-
-    ret = find_vdi_name(s, vdi, (uint32_t)snap_id, tag, &vid, true, errp);
-    if (ret) {
-        goto err;
-    }
-
-    /*
-     * 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 (snap_id || tag[0]) {
-        trace_sheepdog_open(vid);
-        s->is_snapshot = true;
-    }
-
-    fd = connect_to_sdog(s, errp);
-    if (fd < 0) {
-        ret = fd;
-        goto err;
-    }
-
-    buf = g_malloc(SD_INODE_SIZE);
-    ret = read_object(fd, s->bs, buf, vid_to_vdi_oid(vid),
-                      0, SD_INODE_SIZE, 0, s->cache_flags);
-
-    closesocket(fd);
-
-    if (ret) {
-        error_setg(errp, "Can't read snapshot inode");
-        goto err;
-    }
-
-    memcpy(&s->inode, buf, sizeof(s->inode));
-
-    bs->total_sectors = s->inode.vdi_size / BDRV_SECTOR_SIZE;
-    bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
-    pstrcpy(s->name, sizeof(s->name), vdi);
-    qemu_co_mutex_init(&s->lock);
-    qemu_co_mutex_init(&s->queue_lock);
-    qemu_co_queue_init(&s->overlapping_queue);
-    qemu_opts_del(opts);
-    g_free(buf);
-    return 0;
-
-err:
-    aio_set_fd_handler(bdrv_get_aio_context(bs), s->fd,
-                       false, NULL, NULL, NULL, NULL);
-    closesocket(s->fd);
-err_no_fd:
-    qemu_opts_del(opts);
-    g_free(buf);
-    return ret;
-}
-
-static int sd_reopen_prepare(BDRVReopenState *state, BlockReopenQueue *queue,
-                             Error **errp)
-{
-    BDRVSheepdogState *s = state->bs->opaque;
-    BDRVSheepdogReopenState *re_s;
-    int ret = 0;
-
-    re_s = state->opaque = g_new0(BDRVSheepdogReopenState, 1);
-
-    re_s->cache_flags = SD_FLAG_CMD_CACHE;
-    if (state->flags & BDRV_O_NOCACHE) {
-        re_s->cache_flags = SD_FLAG_CMD_DIRECT;
-    }
-
-    re_s->fd = get_sheep_fd(s, errp);
-    if (re_s->fd < 0) {
-        ret = re_s->fd;
-        return ret;
-    }
-
-    return ret;
-}
-
-static void sd_reopen_commit(BDRVReopenState *state)
-{
-    BDRVSheepdogReopenState *re_s = state->opaque;
-    BDRVSheepdogState *s = state->bs->opaque;
-
-    if (s->fd) {
-        aio_set_fd_handler(s->aio_context, s->fd, false,
-                           NULL, NULL, NULL, NULL);
-        closesocket(s->fd);
-    }
-
-    s->fd = re_s->fd;
-    s->cache_flags = re_s->cache_flags;
-
-    g_free(state->opaque);
-    state->opaque = NULL;
-
-    return;
-}
-
-static void sd_reopen_abort(BDRVReopenState *state)
-{
-    BDRVSheepdogReopenState *re_s = state->opaque;
-    BDRVSheepdogState *s = state->bs->opaque;
-
-    if (re_s == NULL) {
-        return;
-    }
-
-    if (re_s->fd) {
-        aio_set_fd_handler(s->aio_context, re_s->fd, false,
-                           NULL, NULL, NULL, NULL);
-        closesocket(re_s->fd);
-    }
-
-    g_free(state->opaque);
-    state->opaque = NULL;
-
-    return;
-}
-
-static int do_sd_create(BDRVSheepdogState *s, uint32_t *vdi_id, int snapshot,
-                        Error **errp)
-{
-    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, errp);
-    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), s->name);
-
-    memset(&hdr, 0, sizeof(hdr));
-    hdr.opcode = SD_OP_NEW_VDI;
-    hdr.base_vdi_id = s->inode.vdi_id;
-
-    wlen = SD_MAX_VDI_LEN;
-
-    hdr.flags = SD_FLAG_CMD_WRITE;
-    hdr.snapid = snapshot;
-
-    hdr.data_length = wlen;
-    hdr.vdi_size = s->inode.vdi_size;
-    hdr.copy_policy = s->inode.copy_policy;
-    hdr.copies = s->inode.nr_copies;
-    hdr.block_size_shift = s->inode.block_size_shift;
-
-    ret = do_req(fd, NULL, (SheepdogReq *)&hdr, buf, &wlen, &rlen);
-
-    closesocket(fd);
-
-    if (ret) {
-        error_setg_errno(errp, -ret, "create failed");
-        return ret;
-    }
-
-    if (rsp->result != SD_RES_SUCCESS) {
-        error_setg(errp, "%s, %s", sd_strerror(rsp->result), s->inode.name);
-        return -EIO;
-    }
-
-    if (vdi_id) {
-        *vdi_id = rsp->vdi_id;
-    }
-
-    return 0;
-}
-
-static int sd_prealloc(BlockDriverState *bs, int64_t old_size, int64_t new_size,
-                       Error **errp)
-{
-    BlockBackend *blk = NULL;
-    BDRVSheepdogState *base = bs->opaque;
-    unsigned long buf_size;
-    uint32_t idx, max_idx;
-    uint32_t object_size;
-    void *buf = NULL;
-    int ret;
-
-    blk = blk_new_with_bs(bs,
-                          BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE | BLK_PERM_RESIZE,
-                          BLK_PERM_ALL, errp);
-
-    if (!blk) {
-        ret = -EPERM;
-        goto out_with_err_set;
-    }
-
-    blk_set_allow_write_beyond_eof(blk, true);
-
-    object_size = (UINT32_C(1) << base->inode.block_size_shift);
-    buf_size = MIN(object_size, SD_DATA_OBJ_SIZE);
-    buf = g_malloc0(buf_size);
-
-    max_idx = DIV_ROUND_UP(new_size, buf_size);
-
-    for (idx = old_size / buf_size; idx < max_idx; idx++) {
-        /*
-         * The created image can be a cloned image, so we need to read
-         * a data from the source image.
-         */
-        ret = blk_pread(blk, idx * buf_size, buf, buf_size);
-        if (ret < 0) {
-            goto out;
-        }
-        ret = blk_pwrite(blk, idx * buf_size, buf, buf_size, 0);
-        if (ret < 0) {
-            goto out;
-        }
-    }
-
-    ret = 0;
-out:
-    if (ret < 0) {
-        error_setg_errno(errp, -ret, "Can't pre-allocate");
-    }
-out_with_err_set:
-    blk_unref(blk);
-    g_free(buf);
-
-    return ret;
-}
-
-static int sd_create_prealloc(BlockdevOptionsSheepdog *location, int64_t size,
-                              Error **errp)
-{
-    BlockDriverState *bs;
-    Visitor *v;
-    QObject *obj = NULL;
-    QDict *qdict;
-    int ret;
-
-    v = qobject_output_visitor_new(&obj);
-    visit_type_BlockdevOptionsSheepdog(v, NULL, &location, &error_abort);
-    visit_free(v);
-
-    qdict = qobject_to(QDict, obj);
-    qdict_flatten(qdict);
-
-    qdict_put_str(qdict, "driver", "sheepdog");
-
-    bs = bdrv_open(NULL, NULL, qdict, BDRV_O_PROTOCOL | BDRV_O_RDWR, errp);
-    if (bs == NULL) {
-        ret = -EIO;
-        goto fail;
-    }
-
-    ret = sd_prealloc(bs, 0, size, errp);
-fail:
-    bdrv_unref(bs);
-    qobject_unref(qdict);
-    return ret;
-}
-
-static int parse_redundancy(BDRVSheepdogState *s, SheepdogRedundancy *opt)
-{
-    struct SheepdogInode *inode = &s->inode;
-
-    switch (opt->type) {
-    case SHEEPDOG_REDUNDANCY_TYPE_FULL:
-        if (opt->u.full.copies > SD_MAX_COPIES || opt->u.full.copies < 1) {
-            return -EINVAL;
-        }
-        inode->copy_policy = 0;
-        inode->nr_copies = opt->u.full.copies;
-        return 0;
-
-    case SHEEPDOG_REDUNDANCY_TYPE_ERASURE_CODED:
-    {
-        int64_t copy = opt->u.erasure_coded.data_strips;
-        int64_t parity = opt->u.erasure_coded.parity_strips;
-
-        if (copy != 2 && copy != 4 && copy != 8 && copy != 16) {
-            return -EINVAL;
-        }
-
-        if (parity >= SD_EC_MAX_STRIP || parity < 1) {
-            return -EINVAL;
-        }
-
-        /*
-         * 4 bits for parity and 4 bits for data.
-         * We have to compress upper data bits because it can't represent 16
-         */
-        inode->copy_policy = ((copy / 2) << 4) + parity;
-        inode->nr_copies = copy + parity;
-        return 0;
-    }
-
-    default:
-        g_assert_not_reached();
-    }
-
-    return -EINVAL;
-}
-
-/*
- * Sheepdog support two kinds of redundancy, full replication and erasure
- * coding.
- *
- * # create a fully replicated vdi with x copies
- * -o redundancy=x (1 <= x <= SD_MAX_COPIES)
- *
- * # create a erasure coded vdi with x data strips and y parity strips
- * -o redundancy=x:y (x must be one of {2,4,8,16} and 1 <= y < SD_EC_MAX_STRIP)
- */
-static SheepdogRedundancy *parse_redundancy_str(const char *opt)
-{
-    SheepdogRedundancy *redundancy;
-    const char *n1, *n2;
-    long copy, parity;
-    char p[10];
-    int ret;
-
-    pstrcpy(p, sizeof(p), opt);
-    n1 = strtok(p, ":");
-    n2 = strtok(NULL, ":");
-
-    if (!n1) {
-        return NULL;
-    }
-
-    ret = qemu_strtol(n1, NULL, 10, &copy);
-    if (ret < 0) {
-        return NULL;
-    }
-
-    redundancy = g_new0(SheepdogRedundancy, 1);
-    if (!n2) {
-        *redundancy = (SheepdogRedundancy) {
-            .type               = SHEEPDOG_REDUNDANCY_TYPE_FULL,
-            .u.full.copies      = copy,
-        };
-    } else {
-        ret = qemu_strtol(n2, NULL, 10, &parity);
-        if (ret < 0) {
-            g_free(redundancy);
-            return NULL;
-        }
-
-        *redundancy = (SheepdogRedundancy) {
-            .type               = SHEEPDOG_REDUNDANCY_TYPE_ERASURE_CODED,
-            .u.erasure_coded    = {
-                .data_strips    = copy,
-                .parity_strips  = parity,
-            },
-        };
-    }
-
-    return redundancy;
-}
-
-static int parse_block_size_shift(BDRVSheepdogState *s,
-                                  BlockdevCreateOptionsSheepdog *opts)
-{
-    struct SheepdogInode *inode = &s->inode;
-    uint64_t object_size;
-    int obj_order;
-
-    if (opts->has_object_size) {
-        object_size = opts->object_size;
-
-        if ((object_size - 1) & object_size) {    /* not a power of 2? */
-            return -EINVAL;
-        }
-        obj_order = ctz32(object_size);
-        if (obj_order < 20 || obj_order > 31) {
-            return -EINVAL;
-        }
-        inode->block_size_shift = (uint8_t)obj_order;
-    }
-
-    return 0;
-}
-
-static int sd_co_create(BlockdevCreateOptions *options, Error **errp)
-{
-    BlockdevCreateOptionsSheepdog *opts = &options->u.sheepdog;
-    int ret = 0;
-    uint32_t vid = 0;
-    char *backing_file = NULL;
-    char *buf = NULL;
-    BDRVSheepdogState *s;
-    uint64_t max_vdi_size;
-    bool prealloc = false;
-
-    assert(options->driver == BLOCKDEV_DRIVER_SHEEPDOG);
-
-    deprecation_warning();
-
-    s = g_new0(BDRVSheepdogState, 1);
-
-    /* Steal SocketAddress from QAPI, set NULL to prevent double free */
-    s->addr = opts->location->server;
-    opts->location->server = NULL;
-
-    if (strlen(opts->location->vdi) >= sizeof(s->name)) {
-        error_setg(errp, "'vdi' string too long");
-        ret = -EINVAL;
-        goto out;
-    }
-    pstrcpy(s->name, sizeof(s->name), opts->location->vdi);
-
-    s->inode.vdi_size = opts->size;
-    backing_file = opts->backing_file;
-
-    if (!opts->has_preallocation) {
-        opts->preallocation = PREALLOC_MODE_OFF;
-    }
-    switch (opts->preallocation) {
-    case PREALLOC_MODE_OFF:
-        prealloc = false;
-        break;
-    case PREALLOC_MODE_FULL:
-        prealloc = true;
-        break;
-    default:
-        error_setg(errp, "Preallocation mode not supported for Sheepdog");
-        ret = -EINVAL;
-        goto out;
-    }
-
-    if (opts->has_redundancy) {
-        ret = parse_redundancy(s, opts->redundancy);
-        if (ret < 0) {
-            error_setg(errp, "Invalid redundancy mode");
-            goto out;
-        }
-    }
-    ret = parse_block_size_shift(s, opts);
-    if (ret < 0) {
-        error_setg(errp, "Invalid object_size."
-                         " obect_size needs to be power of 2"
-                         " and be limited from 2^20 to 2^31");
-        goto out;
-    }
-
-    if (opts->has_backing_file) {
-        BlockBackend *blk;
-        BDRVSheepdogState *base;
-        BlockDriver *drv;
-
-        /* Currently, only Sheepdog backing image is supported. */
-        drv = bdrv_find_protocol(opts->backing_file, true, NULL);
-        if (!drv || strcmp(drv->protocol_name, "sheepdog") != 0) {
-            error_setg(errp, "backing_file must be a sheepdog image");
-            ret = -EINVAL;
-            goto out;
-        }
-
-        blk = blk_new_open(opts->backing_file, NULL, NULL,
-                           BDRV_O_PROTOCOL, errp);
-        if (blk == NULL) {
-            ret = -EIO;
-            goto out;
-        }
-
-        base = blk_bs(blk)->opaque;
-
-        if (!is_snapshot(&base->inode)) {
-            error_setg(errp, "cannot clone from a non snapshot vdi");
-            blk_unref(blk);
-            ret = -EINVAL;
-            goto out;
-        }
-        s->inode.vdi_id = base->inode.vdi_id;
-        blk_unref(blk);
-    }
-
-    s->aio_context = qemu_get_aio_context();
-
-    /* if block_size_shift is not specified, get cluster default value */
-    if (s->inode.block_size_shift == 0) {
-        SheepdogVdiReq hdr;
-        SheepdogClusterRsp *rsp = (SheepdogClusterRsp *)&hdr;
-        int fd;
-        unsigned int wlen = 0, rlen = 0;
-
-        fd = connect_to_sdog(s, errp);
-        if (fd < 0) {
-            ret = fd;
-            goto out;
-        }
-
-        memset(&hdr, 0, sizeof(hdr));
-        hdr.opcode = SD_OP_GET_CLUSTER_DEFAULT;
-        hdr.proto_ver = SD_PROTO_VER;
-
-        ret = do_req(fd, NULL, (SheepdogReq *)&hdr,
-                     NULL, &wlen, &rlen);
-        closesocket(fd);
-        if (ret) {
-            error_setg_errno(errp, -ret, "failed to get cluster default");
-            goto out;
-        }
-        if (rsp->result == SD_RES_SUCCESS) {
-            s->inode.block_size_shift = rsp->block_size_shift;
-        } else {
-            s->inode.block_size_shift = SD_DEFAULT_BLOCK_SIZE_SHIFT;
-        }
-    }
-
-    max_vdi_size = (UINT64_C(1) << s->inode.block_size_shift) * MAX_DATA_OBJS;
-
-    if (s->inode.vdi_size > max_vdi_size) {
-        error_setg(errp, "An image is too large."
-                         " The maximum image size is %"PRIu64 "GB",
-                         max_vdi_size / 1024 / 1024 / 1024);
-        ret = -EINVAL;
-        goto out;
-    }
-
-    ret = do_sd_create(s, &vid, 0, errp);
-    if (ret) {
-        goto out;
-    }
-
-    if (prealloc) {
-        ret = sd_create_prealloc(opts->location, opts->size, errp);
-    }
-out:
-    g_free(backing_file);
-    g_free(buf);
-    g_free(s->addr);
-    g_free(s);
-    return ret;
-}
-
-static int coroutine_fn sd_co_create_opts(BlockDriver *drv,
-                                          const char *filename,
-                                          QemuOpts *opts,
-                                          Error **errp)
-{
-    BlockdevCreateOptions *create_options = NULL;
-    QDict *qdict = NULL, *location_qdict;
-    Visitor *v;
-    char *redundancy = NULL;
-    Error *local_err = NULL;
-    int ret;
-    char *backing_fmt = NULL;
-
-    redundancy = qemu_opt_get_del(opts, BLOCK_OPT_REDUNDANCY);
-    backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
-
-    if (backing_fmt && strcmp(backing_fmt, "sheepdog") != 0) {
-        error_setg(errp, "backing_file must be a sheepdog image");
-        ret = -EINVAL;
-        goto fail;
-    }
-
-    qdict = qemu_opts_to_qdict(opts, NULL);
-    qdict_put_str(qdict, "driver", "sheepdog");
-
-    location_qdict = qdict_new();
-    qdict_put(qdict, "location", location_qdict);
-
-    sd_parse_filename(filename, location_qdict, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        ret = -EINVAL;
-        goto fail;
-    }
-
-    qdict_flatten(qdict);
-
-    /* Change legacy command line options into QMP ones */
-    static const QDictRenames opt_renames[] = {
-        { BLOCK_OPT_BACKING_FILE,       "backing-file" },
-        { BLOCK_OPT_OBJECT_SIZE,        "object-size" },
-        { NULL, NULL },
-    };
-
-    if (!qdict_rename_keys(qdict, opt_renames, errp)) {
-        ret = -EINVAL;
-        goto fail;
-    }
-
-    /* Get the QAPI object */
-    v = qobject_input_visitor_new_flat_confused(qdict, errp);
-    if (!v) {
-        ret = -EINVAL;
-        goto fail;
-    }
-
-    visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
-    visit_free(v);
-    if (!create_options) {
-        ret = -EINVAL;
-        goto fail;
-    }
-
-    assert(create_options->driver == BLOCKDEV_DRIVER_SHEEPDOG);
-    create_options->u.sheepdog.size =
-        ROUND_UP(create_options->u.sheepdog.size, BDRV_SECTOR_SIZE);
-
-    if (redundancy) {
-        create_options->u.sheepdog.has_redundancy = true;
-        create_options->u.sheepdog.redundancy =
-            parse_redundancy_str(redundancy);
-        if (create_options->u.sheepdog.redundancy == NULL) {
-            error_setg(errp, "Invalid redundancy mode");
-            ret = -EINVAL;
-            goto fail;
-        }
-    }
-
-    ret = sd_co_create(create_options, errp);
-fail:
-    qapi_free_BlockdevCreateOptions(create_options);
-    qobject_unref(qdict);
-    g_free(redundancy);
-    g_free(backing_fmt);
-    return ret;
-}
-
-static void sd_close(BlockDriverState *bs)
-{
-    Error *local_err = NULL;
-    BDRVSheepdogState *s = bs->opaque;
-    SheepdogVdiReq hdr;
-    SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
-    unsigned int wlen, rlen = 0;
-    int fd, ret;
-
-    trace_sheepdog_close(s->name);
-
-    fd = connect_to_sdog(s, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        return;
-    }
-
-    memset(&hdr, 0, sizeof(hdr));
-
-    hdr.opcode = SD_OP_RELEASE_VDI;
-    hdr.type = LOCK_TYPE_NORMAL;
-    hdr.base_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, s->bs, (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);
-    }
-
-    aio_set_fd_handler(bdrv_get_aio_context(bs), s->fd,
-                       false, NULL, NULL, NULL, NULL);
-    closesocket(s->fd);
-    qapi_free_SocketAddress(s->addr);
-}
-
-static int64_t sd_getlength(BlockDriverState *bs)
-{
-    BDRVSheepdogState *s = bs->opaque;
-
-    return s->inode.vdi_size;
-}
-
-static int coroutine_fn sd_co_truncate(BlockDriverState *bs, int64_t offset,
-                                       bool exact, PreallocMode prealloc,
-                                       BdrvRequestFlags flags, Error **errp)
-{
-    BDRVSheepdogState *s = bs->opaque;
-    int ret, fd;
-    unsigned int datalen;
-    uint64_t max_vdi_size;
-    int64_t old_size = s->inode.vdi_size;
-
-    if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_FULL) {
-        error_setg(errp, "Unsupported preallocation mode '%s'",
-                   PreallocMode_str(prealloc));
-        return -ENOTSUP;
-    }
-
-    max_vdi_size = (UINT64_C(1) << s->inode.block_size_shift) * MAX_DATA_OBJS;
-    if (offset < old_size) {
-        error_setg(errp, "shrinking is not supported");
-        return -EINVAL;
-    } else if (offset > max_vdi_size) {
-        error_setg(errp, "too big image size");
-        return -EINVAL;
-    }
-
-    fd = connect_to_sdog(s, errp);
-    if (fd < 0) {
-        return fd;
-    }
-
-    /* we don't need to update entire object */
-    datalen = SD_INODE_HEADER_SIZE;
-    s->inode.vdi_size = offset;
-    ret = write_object(fd, s->bs, (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_setg_errno(errp, -ret, "failed to update an inode");
-        return ret;
-    }
-
-    if (prealloc == PREALLOC_MODE_FULL) {
-        ret = sd_prealloc(bs, old_size, offset, errp);
-        if (ret < 0) {
-            return ret;
-        }
-    }
-
-    return 0;
-}
-
-/*
- * This function is called after writing data objects.  If we need to
- * update metadata, this sends a write request to the vdi object.
- */
-static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
-{
-    BDRVSheepdogState *s = acb->s;
-    struct iovec iov;
-    AIOReq *aio_req;
-    uint32_t offset, data_len, mn, mx;
-
-    mn = acb->min_dirty_data_idx;
-    mx = acb->max_dirty_data_idx;
-    if (mn <= mx) {
-        /* we need to update the vdi object. */
-        ++acb->nr_pending;
-        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]);
-
-        acb->min_dirty_data_idx = UINT32_MAX;
-        acb->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, false, 0, offset);
-        add_aio_request(s, aio_req, &iov, 1, AIOCB_WRITE_UDATA);
-        if (--acb->nr_pending) {
-            qemu_coroutine_yield();
-        }
-    }
-}
-
-/* Delete current working VDI on the snapshot chain */
-static bool sd_delete(BDRVSheepdogState *s)
-{
-    Error *local_err = NULL;
-    unsigned int wlen = SD_MAX_VDI_LEN, rlen = 0;
-    SheepdogVdiReq hdr = {
-        .opcode = SD_OP_DEL_VDI,
-        .base_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, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        return false;
-    }
-
-    ret = do_req(fd, s->bs, (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)
-{
-    Error *local_err = NULL;
-    int ret, fd;
-    uint32_t vid;
-    char *buf;
-    bool deleted;
-
-    trace_sheepdog_create_branch_snapshot(s->inode.vdi_id);
-
-    buf = g_malloc(SD_INODE_SIZE);
-
-    /*
-     * Even If deletion fails, we will just create extra snapshot based on
-     * the working VDI which was supposed to be deleted. So no need to
-     * false bail out.
-     */
-    deleted = sd_delete(s);
-    ret = do_sd_create(s, &vid, !deleted, &local_err);
-    if (ret) {
-        error_report_err(local_err);
-        goto out;
-    }
-
-    trace_sheepdog_create_branch_created(vid);
-
-    fd = connect_to_sdog(s, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        ret = fd;
-        goto out;
-    }
-
-    ret = read_object(fd, s->bs, 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;
-    trace_sheepdog_create_branch_new(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 void coroutine_fn sd_co_rw_vector(SheepdogAIOCB *acb)
-{
-    int ret = 0;
-    unsigned long len, done = 0, total = acb->nb_sectors * BDRV_SECTOR_SIZE;
-    unsigned long idx;
-    uint32_t object_size;
-    uint64_t oid;
-    uint64_t offset;
-    BDRVSheepdogState *s = acb->s;
-    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;
-            return;
-        }
-    }
-
-    object_size = (UINT32_C(1) << inode->block_size_shift);
-    idx = acb->sector_num * BDRV_SECTOR_SIZE / object_size;
-    offset = (acb->sector_num * BDRV_SECTOR_SIZE) % object_size;
-
-    /*
-     * 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, object_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 != object_size || inode->data_vdi_id[idx] == 0) {
-                goto done;
-            }
-            break;
-        default:
-            break;
-        }
-
-        if (create) {
-            trace_sheepdog_co_rw_vector_update(inode->vdi_id, oid,
-                                  vid_to_data_oid(inode->data_vdi_id[idx], idx),
-                                  idx);
-            oid = vid_to_data_oid(inode->vdi_id, idx);
-            trace_sheepdog_co_rw_vector_new(oid);
-        }
-
-        aio_req = alloc_aio_req(s, acb, oid, len, offset, flags, create,
-                                old_oid,
-                                acb->aiocb_type == AIOCB_DISCARD_OBJ ?
-                                0 : done);
-        add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
-                        acb->aiocb_type);
-    done:
-        offset = 0;
-        idx++;
-        done += len;
-    }
-    if (--acb->nr_pending) {
-        qemu_coroutine_yield();
-    }
-}
-
-static void sd_aio_complete(SheepdogAIOCB *acb)
-{
-    BDRVSheepdogState *s;
-    if (acb->aiocb_type == AIOCB_FLUSH_CACHE) {
-        return;
-    }
-
-    s = acb->s;
-    qemu_co_mutex_lock(&s->queue_lock);
-    QLIST_REMOVE(acb, aiocb_siblings);
-    qemu_co_queue_restart_all(&s->overlapping_queue);
-    qemu_co_mutex_unlock(&s->queue_lock);
-}
-
-static coroutine_fn int sd_co_writev(BlockDriverState *bs, int64_t sector_num,
-                                     int nb_sectors, QEMUIOVector *qiov,
-                                     int flags)
-{
-    SheepdogAIOCB acb;
-    int ret;
-    int64_t offset = (sector_num + nb_sectors) * BDRV_SECTOR_SIZE;
-    BDRVSheepdogState *s = bs->opaque;
-
-    assert(!flags);
-    if (offset > s->inode.vdi_size) {
-        ret = sd_co_truncate(bs, offset, false, PREALLOC_MODE_OFF, 0, NULL);
-        if (ret < 0) {
-            return ret;
-        }
-    }
-
-    sd_aio_setup(&acb, s, qiov, sector_num, nb_sectors, AIOCB_WRITE_UDATA);
-    sd_co_rw_vector(&acb);
-    sd_write_done(&acb);
-    sd_aio_complete(&acb);
-
-    return acb.ret;
-}
-
-static coroutine_fn int sd_co_readv(BlockDriverState *bs, int64_t sector_num,
-                       int nb_sectors, QEMUIOVector *qiov)
-{
-    SheepdogAIOCB acb;
-    BDRVSheepdogState *s = bs->opaque;
-
-    sd_aio_setup(&acb, s, qiov, sector_num, nb_sectors, AIOCB_READ_UDATA);
-    sd_co_rw_vector(&acb);
-    sd_aio_complete(&acb);
-
-    return acb.ret;
-}
-
-static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
-{
-    BDRVSheepdogState *s = bs->opaque;
-    SheepdogAIOCB acb;
-    AIOReq *aio_req;
-
-    if (s->cache_flags != SD_FLAG_CMD_CACHE) {
-        return 0;
-    }
-
-    sd_aio_setup(&acb, s, NULL, 0, 0, AIOCB_FLUSH_CACHE);
-
-    acb.nr_pending++;
-    aio_req = alloc_aio_req(s, &acb, vid_to_vdi_oid(s->inode.vdi_id),
-                            0, 0, 0, false, 0, 0);
-    add_aio_request(s, aio_req, NULL, 0, acb.aiocb_type);
-
-    if (--acb.nr_pending) {
-        qemu_coroutine_yield();
-    }
-
-    sd_aio_complete(&acb);
-    return acb.ret;
-}
-
-static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
-{
-    Error *local_err = NULL;
-    BDRVSheepdogState *s = bs->opaque;
-    int ret, fd;
-    uint32_t new_vid;
-    SheepdogInode *inode;
-    unsigned int datalen;
-
-    trace_sheepdog_snapshot_create_info(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;
-    }
-
-    trace_sheepdog_snapshot_create(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_HEADER_SIZE;
-    inode = g_malloc(datalen);
-
-    /* refresh inode. */
-    fd = connect_to_sdog(s, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        ret = fd;
-        goto cleanup;
-    }
-
-    ret = write_object(fd, s->bs, (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, &new_vid, 1, &local_err);
-    if (ret < 0) {
-        error_reportf_err(local_err,
-                          "failed to create inode for snapshot: ");
-        goto cleanup;
-    }
-
-    ret = read_object(fd, s->bs, (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);
-    trace_sheepdog_snapshot_create_inode(s->inode.name, s->inode.snap_id,
-                                         s->inode.vdi_id);
-
-cleanup:
-    g_free(inode);
-    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 specified 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;
-
-    if (!sd_parse_snapid_or_tag(snapshot_id, &snapid, tag)) {
-        return -EINVAL;
-    }
-
-    old_s = g_new(BDRVSheepdogState, 1);
-
-    memcpy(old_s, s, sizeof(BDRVSheepdogState));
-
-    ret = reload_inode(s, snapid, tag);
-    if (ret) {
-        goto out;
-    }
-
-    ret = sd_create_branch(s);
-    if (ret) {
-        goto out;
-    }
-
-    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;
-}
-
-#define NR_BATCHED_DISCARD 128
-
-static int remove_objects(BDRVSheepdogState *s, Error **errp)
-{
-    int fd, i = 0, nr_objs = 0;
-    int ret;
-    SheepdogInode *inode = &s->inode;
-
-    fd = connect_to_sdog(s, errp);
-    if (fd < 0) {
-        return fd;
-    }
-
-    nr_objs = count_data_objs(inode);
-    while (i < nr_objs) {
-        int start_idx, nr_filled_idx;
-
-        while (i < nr_objs && !inode->data_vdi_id[i]) {
-            i++;
-        }
-        start_idx = i;
-
-        nr_filled_idx = 0;
-        while (i < nr_objs && nr_filled_idx < NR_BATCHED_DISCARD) {
-            if (inode->data_vdi_id[i]) {
-                inode->data_vdi_id[i] = 0;
-                nr_filled_idx++;
-            }
-
-            i++;
-        }
-
-        ret = write_object(fd, s->bs,
-                           (char *)&inode->data_vdi_id[start_idx],
-                           vid_to_vdi_oid(s->inode.vdi_id), inode->nr_copies,
-                           (i - start_idx) * sizeof(uint32_t),
-                           offsetof(struct SheepdogInode,
-                                    data_vdi_id[start_idx]),
-                           false, s->cache_flags);
-        if (ret < 0) {
-            error_setg(errp, "Failed to discard snapshot inode");
-            goto out;
-        }
-    }
-
-    ret = 0;
-out:
-    closesocket(fd);
-    return ret;
-}
-
-static int sd_snapshot_delete(BlockDriverState *bs,
-                              const char *snapshot_id,
-                              const char *name,
-                              Error **errp)
-{
-    /*
-     * FIXME should delete the snapshot matching both @snapshot_id and
-     * @name, but @name not used here
-     */
-    unsigned long snap_id = 0;
-    char snap_tag[SD_MAX_VDI_TAG_LEN];
-    int fd, ret;
-    char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN];
-    BDRVSheepdogState *s = bs->opaque;
-    unsigned int wlen = SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN, rlen = 0;
-    uint32_t vid;
-    SheepdogVdiReq hdr = {
-        .opcode = SD_OP_DEL_VDI,
-        .data_length = wlen,
-        .flags = SD_FLAG_CMD_WRITE,
-    };
-    SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
-
-    ret = remove_objects(s, errp);
-    if (ret) {
-        return ret;
-    }
-
-    memset(buf, 0, sizeof(buf));
-    memset(snap_tag, 0, sizeof(snap_tag));
-    pstrcpy(buf, SD_MAX_VDI_LEN, s->name);
-    /* TODO Use sd_parse_snapid() once this mess is cleaned up */
-    ret = qemu_strtoul(snapshot_id, NULL, 10, &snap_id);
-    if (ret || snap_id > UINT32_MAX) {
-        /*
-         * FIXME Since qemu_strtoul() returns -EINVAL when
-         * @snapshot_id is null, @snapshot_id is mandatory.  Correct
-         * would be to require at least one of @snapshot_id and @name.
-         */
-        error_setg(errp, "Invalid snapshot ID: %s",
-                         snapshot_id ? snapshot_id : "<null>");
-        return -EINVAL;
-    }
-
-    if (snap_id) {
-        hdr.snapid = (uint32_t) snap_id;
-    } else {
-        /* FIXME I suspect we should use @name here */
-        /* FIXME don't truncate silently */
-        pstrcpy(snap_tag, sizeof(snap_tag), snapshot_id);
-        pstrcpy(buf + SD_MAX_VDI_LEN, SD_MAX_VDI_TAG_LEN, snap_tag);
-    }
-
-    ret = find_vdi_name(s, s->name, snap_id, snap_tag, &vid, true, errp);
-    if (ret) {
-        return ret;
-    }
-
-    fd = connect_to_sdog(s, errp);
-    if (fd < 0) {
-        return fd;
-    }
-
-    ret = do_req(fd, s->bs, (SheepdogReq *)&hdr,
-                 buf, &wlen, &rlen);
-    closesocket(fd);
-    if (ret) {
-        error_setg_errno(errp, -ret, "Couldn't send request to server");
-        return ret;
-    }
-
-    switch (rsp->result) {
-    case SD_RES_NO_VDI:
-        error_setg(errp, "Can't find the snapshot");
-        return -ENOENT;
-    case SD_RES_SUCCESS:
-        break;
-    default:
-        error_setg(errp, "%s", sd_strerror(rsp->result));
-        return -EIO;
-    }
-
-    return 0;
-}
-
-static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
-{
-    Error *local_err = NULL;
-    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;
-    SheepdogInode *inode;
-    unsigned long *vdi_inuse;
-    unsigned int start_nr;
-    uint64_t hval;
-    uint32_t vid;
-
-    vdi_inuse = g_malloc(max);
-    inode = g_malloc(SD_INODE_HEADER_SIZE);
-
-    fd = connect_to_sdog(s, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        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, s->bs, &req, vdi_inuse, &wlen, &rlen);
-
-    closesocket(fd);
-    if (ret) {
-        goto out;
-    }
-
-    sn_tab = g_new0(QEMUSnapshotInfo, nr);
-
-    /* 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, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        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, s->bs, (char *)inode,
-                          vid_to_vdi_oid(vid),
-                          0, SD_INODE_HEADER_SIZE, 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),
-                     "%" PRIu32, 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);
-    g_free(inode);
-
-    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)
-{
-    Error *local_err = NULL;
-    bool create;
-    int fd, ret = 0, remaining = size;
-    unsigned int data_len;
-    uint64_t vmstate_oid;
-    uint64_t offset;
-    uint32_t vdi_index;
-    uint32_t vdi_id = load ? s->inode.parent_vdi_id : s->inode.vdi_id;
-    uint32_t object_size = (UINT32_C(1) << s->inode.block_size_shift);
-
-    fd = connect_to_sdog(s, &local_err);
-    if (fd < 0) {
-        error_report_err(local_err);
-        return fd;
-    }
-
-    while (remaining) {
-        vdi_index = pos / object_size;
-        offset = pos % object_size;
-
-        data_len = MIN(remaining, object_size - offset);
-
-        vmstate_oid = vid_to_vmstate_oid(vdi_id, vdi_index);
-
-        create = (offset == 0);
-        if (load) {
-            ret = read_object(fd, s->bs, (char *)data, vmstate_oid,
-                              s->inode.nr_copies, data_len, offset,
-                              s->cache_flags);
-        } else {
-            ret = write_object(fd, s->bs, (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, QEMUIOVector *qiov,
-                           int64_t pos)
-{
-    BDRVSheepdogState *s = bs->opaque;
-    void *buf;
-    int ret;
-
-    buf = qemu_blockalign(bs, qiov->size);
-    ret = do_load_save_vmstate(s, buf, pos, qiov->size, 1);
-    qemu_iovec_from_buf(qiov, 0, buf, qiov->size);
-    qemu_vfree(buf);
-
-    return ret;
-}
-
-
-static coroutine_fn int sd_co_pdiscard(BlockDriverState *bs, int64_t offset,
-                                      int bytes)
-{
-    SheepdogAIOCB acb;
-    BDRVSheepdogState *s = bs->opaque;
-    QEMUIOVector discard_iov;
-    struct iovec iov;
-    uint32_t zero = 0;
-
-    if (!s->discard_supported) {
-        return 0;
-    }
-
-    memset(&discard_iov, 0, sizeof(discard_iov));
-    memset(&iov, 0, sizeof(iov));
-    iov.iov_base = &zero;
-    iov.iov_len = sizeof(zero);
-    discard_iov.iov = &iov;
-    discard_iov.niov = 1;
-    if (!QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE)) {
-        return -ENOTSUP;
-    }
-    sd_aio_setup(&acb, s, &discard_iov, offset >> BDRV_SECTOR_BITS,
-                 bytes >> BDRV_SECTOR_BITS, AIOCB_DISCARD_OBJ);
-    sd_co_rw_vector(&acb);
-    sd_aio_complete(&acb);
-
-    return acb.ret;
-}
-
-static coroutine_fn int
-sd_co_block_status(BlockDriverState *bs, bool want_zero, int64_t offset,
-                   int64_t bytes, int64_t *pnum, int64_t *map,
-                   BlockDriverState **file)
-{
-    BDRVSheepdogState *s = bs->opaque;
-    SheepdogInode *inode = &s->inode;
-    uint32_t object_size = (UINT32_C(1) << inode->block_size_shift);
-    unsigned long start = offset / object_size,
-                  end = DIV_ROUND_UP(offset + bytes, object_size);
-    unsigned long idx;
-    *map = offset;
-    int ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
-
-    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) * object_size;
-    if (*pnum > bytes) {
-        *pnum = bytes;
-    }
-    if (ret > 0 && ret & BDRV_BLOCK_OFFSET_VALID) {
-        *file = bs;
-    }
-    return ret;
-}
-
-static int64_t sd_get_allocated_file_size(BlockDriverState *bs)
-{
-    BDRVSheepdogState *s = bs->opaque;
-    SheepdogInode *inode = &s->inode;
-    uint32_t object_size = (UINT32_C(1) << inode->block_size_shift);
-    unsigned long i, last = DIV_ROUND_UP(inode->vdi_size, object_size);
-    uint64_t size = 0;
-
-    for (i = 0; i < last; i++) {
-        if (inode->data_vdi_id[i] == 0) {
-            continue;
-        }
-        size += object_size;
-    }
-    return size;
-}
-
-static QemuOptsList sd_create_opts = {
-    .name = "sheepdog-create-opts",
-    .head = QTAILQ_HEAD_INITIALIZER(sd_create_opts.head),
-    .desc = {
-        {
-            .name = BLOCK_OPT_SIZE,
-            .type = QEMU_OPT_SIZE,
-            .help = "Virtual disk size"
-        },
-        {
-            .name = BLOCK_OPT_BACKING_FILE,
-            .type = QEMU_OPT_STRING,
-            .help = "File name of a base image"
-        },
-        {
-            .name = BLOCK_OPT_BACKING_FMT,
-            .type = QEMU_OPT_STRING,
-            .help = "Must be 'sheepdog' if present",
-        },
-        {
-            .name = BLOCK_OPT_PREALLOC,
-            .type = QEMU_OPT_STRING,
-            .help = "Preallocation mode (allowed values: off, full)"
-        },
-        {
-            .name = BLOCK_OPT_REDUNDANCY,
-            .type = QEMU_OPT_STRING,
-            .help = "Redundancy of the image"
-        },
-        {
-            .name = BLOCK_OPT_OBJECT_SIZE,
-            .type = QEMU_OPT_SIZE,
-            .help = "Object size of the image"
-        },
-        { /* end of list */ }
-    }
-};
-
-static const char *const sd_strong_runtime_opts[] = {
-    "vdi",
-    "snap-id",
-    "tag",
-    "server.",
-
-    NULL
-};
-
-static BlockDriver bdrv_sheepdog = {
-    .format_name                  = "sheepdog",
-    .protocol_name                = "sheepdog",
-    .instance_size                = sizeof(BDRVSheepdogState),
-    .bdrv_parse_filename          = sd_parse_filename,
-    .bdrv_file_open               = sd_open,
-    .bdrv_reopen_prepare          = sd_reopen_prepare,
-    .bdrv_reopen_commit           = sd_reopen_commit,
-    .bdrv_reopen_abort            = sd_reopen_abort,
-    .bdrv_close                   = sd_close,
-    .bdrv_co_create               = sd_co_create,
-    .bdrv_co_create_opts          = sd_co_create_opts,
-    .bdrv_has_zero_init           = bdrv_has_zero_init_1,
-    .bdrv_getlength               = sd_getlength,
-    .bdrv_get_allocated_file_size = sd_get_allocated_file_size,
-    .bdrv_co_truncate             = sd_co_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_pdiscard             = sd_co_pdiscard,
-    .bdrv_co_block_status         = sd_co_block_status,
-
-    .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,
-
-    .bdrv_detach_aio_context      = sd_detach_aio_context,
-    .bdrv_attach_aio_context      = sd_attach_aio_context,
-
-    .create_opts                  = &sd_create_opts,
-    .strong_runtime_opts          = sd_strong_runtime_opts,
-};
-
-static BlockDriver bdrv_sheepdog_tcp = {
-    .format_name                  = "sheepdog",
-    .protocol_name                = "sheepdog+tcp",
-    .instance_size                = sizeof(BDRVSheepdogState),
-    .bdrv_parse_filename          = sd_parse_filename,
-    .bdrv_file_open               = sd_open,
-    .bdrv_reopen_prepare          = sd_reopen_prepare,
-    .bdrv_reopen_commit           = sd_reopen_commit,
-    .bdrv_reopen_abort            = sd_reopen_abort,
-    .bdrv_close                   = sd_close,
-    .bdrv_co_create               = sd_co_create,
-    .bdrv_co_create_opts          = sd_co_create_opts,
-    .bdrv_has_zero_init           = bdrv_has_zero_init_1,
-    .bdrv_getlength               = sd_getlength,
-    .bdrv_get_allocated_file_size = sd_get_allocated_file_size,
-    .bdrv_co_truncate             = sd_co_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_pdiscard             = sd_co_pdiscard,
-    .bdrv_co_block_status         = sd_co_block_status,
-
-    .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,
-
-    .bdrv_detach_aio_context      = sd_detach_aio_context,
-    .bdrv_attach_aio_context      = sd_attach_aio_context,
-
-    .create_opts                  = &sd_create_opts,
-    .strong_runtime_opts          = sd_strong_runtime_opts,
-};
-
-static BlockDriver bdrv_sheepdog_unix = {
-    .format_name                  = "sheepdog",
-    .protocol_name                = "sheepdog+unix",
-    .instance_size                = sizeof(BDRVSheepdogState),
-    .bdrv_parse_filename          = sd_parse_filename,
-    .bdrv_file_open               = sd_open,
-    .bdrv_reopen_prepare          = sd_reopen_prepare,
-    .bdrv_reopen_commit           = sd_reopen_commit,
-    .bdrv_reopen_abort            = sd_reopen_abort,
-    .bdrv_close                   = sd_close,
-    .bdrv_co_create               = sd_co_create,
-    .bdrv_co_create_opts          = sd_co_create_opts,
-    .bdrv_has_zero_init           = bdrv_has_zero_init_1,
-    .bdrv_getlength               = sd_getlength,
-    .bdrv_get_allocated_file_size = sd_get_allocated_file_size,
-    .bdrv_co_truncate             = sd_co_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_pdiscard             = sd_co_pdiscard,
-    .bdrv_co_block_status         = sd_co_block_status,
-
-    .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,
-
-    .bdrv_detach_aio_context      = sd_detach_aio_context,
-    .bdrv_attach_aio_context      = sd_attach_aio_context,
-
-    .create_opts                  = &sd_create_opts,
-    .strong_runtime_opts          = sd_strong_runtime_opts,
-};
-
-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);
diff --git a/block/trace-events b/block/trace-events
index 1a12d63..31062ed 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -207,19 +207,5 @@ file_FindEjectableOpticalMedia(const char *media) "Matching using %s"
 file_setup_cdrom(const char *partition) "Using %s as optical disc"
 file_hdev_is_sg(int type, int version) "SG device found: type=%d, version=%d"
 
-# sheepdog.c
-sheepdog_reconnect_to_sdog(void) "Wait for connection to be established"
-sheepdog_aio_read_response(void) "disable cache since the server doesn't support it"
-sheepdog_open(uint32_t vid) "0x%" PRIx32 " snapshot inode was open"
-sheepdog_close(const char *name) "%s"
-sheepdog_create_branch_snapshot(uint32_t vdi) "0x%" PRIx32 " is snapshot"
-sheepdog_create_branch_created(uint32_t vdi) "0x%" PRIx32 " is created"
-sheepdog_create_branch_new(uint32_t vdi) "0x%" PRIx32 " was newly created"
-sheepdog_co_rw_vector_update(uint32_t vdi, uint64_t oid, uint64_t data, long idx) "update ino (%" PRIu32 ") %" PRIu64 " %" PRIu64 " %ld"
-sheepdog_co_rw_vector_new(uint64_t oid) "new oid 0x%" PRIx64
-sheepdog_snapshot_create_info(const char *sn_name, const char *id, const char *name, int64_t size, int is_snapshot) "sn_info: name %s id_str %s s: name %s vm_state_size %" PRId64 " " "is_snapshot %d"
-sheepdog_snapshot_create(const char *sn_name, const char *id) "%s %s"
-sheepdog_snapshot_create_inode(const char *name, uint32_t snap, uint32_t vdi) "s->inode: name %s snap_id 0x%" PRIx32 " vdi 0x%" PRIx32
-
 # ssh.c
 sftp_error(const char *op, const char *ssh_err, int ssh_err_code, int sftp_err_code) "%s failed: %s (libssh error code: %d, sftp error code: %d)"
diff --git a/configure b/configure
index f3fe75d..8759304 100755
--- a/configure
+++ b/configure
@@ -447,7 +447,6 @@ vdi=${default_feature:-yes}
 vvfat=${default_feature:-yes}
 qed=${default_feature:-yes}
 parallels=${default_feature:-yes}
-sheepdog="no"
 libxml2="$default_feature"
 debug_mutex="no"
 libpmem="$default_feature"
@@ -1478,10 +1477,6 @@ for opt do
   ;;
   --enable-parallels) parallels="yes"
   ;;
-  --disable-sheepdog) sheepdog="no"
-  ;;
-  --enable-sheepdog) sheepdog="yes"
-  ;;
   --disable-vhost-user) vhost_user="no"
   ;;
   --enable-vhost-user) vhost_user="yes"
@@ -1916,7 +1911,6 @@ disabled with --disable-FEATURE, default is enabled if available
   vvfat           vvfat image format support
   qed             qed image format support
   parallels       parallels image format support
-  sheepdog        sheepdog block driver support (deprecated)
   crypto-afalg    Linux AF_ALG crypto backend driver
   capstone        capstone disassembler support
   debug-mutex     mutex debugging support
@@ -6106,10 +6100,6 @@ fi
 if test "$parallels" = "yes" ; then
   echo "CONFIG_PARALLELS=y" >> $config_host_mak
 fi
-if test "$sheepdog" = "yes" ; then
-  add_to deprecated_features "sheepdog"
-  echo "CONFIG_SHEEPDOG=y" >> $config_host_mak
-fi
 if test "$have_mlockall" = "yes" ; then
   echo "HAVE_MLOCKALL=y" >> $config_host_mak
 fi
diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
index cd91c45..7d34da9 100644
--- a/docs/system/deprecated.rst
+++ b/docs/system/deprecated.rst
@@ -285,15 +285,6 @@ The above, converted to the current supported format::
 
   json:{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"}
 
-``sheepdog`` driver (since 5.2.0)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-The ``sheepdog`` block device driver is deprecated. The corresponding upstream
-server project is no longer actively maintained. Users are recommended to switch
-to an alternative distributed block device driver such as RBD. The
-``qemu-img convert`` command can be used to liberate existing data by moving
-it out of sheepdog volumes into an alternative storage backend.
-
 linux-user mode CPUs
 --------------------
 
diff --git a/docs/system/device-url-syntax.rst.inc b/docs/system/device-url-syntax.rst.inc
index 6f6ec83..d15a021 100644
--- a/docs/system/device-url-syntax.rst.inc
+++ b/docs/system/device-url-syntax.rst.inc
@@ -85,24 +85,6 @@ These are specified using a special URL syntax.
    Currently authentication must be done using ssh-agent. Other
    authentication methods may be supported in future.
 
-``Sheepdog``
-   Sheepdog is a distributed storage system for QEMU. QEMU supports
-   using either local sheepdog devices or remote networked devices.
-
-   Syntax for specifying a sheepdog device
-
-   ::
-
-      sheepdog[+tcp|+unix]://[host:port]/vdiname[?socket=path][#snapid|#tag]
-
-   Example
-
-   .. parsed-literal::
-
-      |qemu_system| --drive file=sheepdog://192.0.2.1:30000/MyVirtualMachine
-
-   See also https://sheepdog.github.io/sheepdog/.
-
 ``GlusterFS``
    GlusterFS is a user space distributed file system. QEMU supports the
    use of GlusterFS volumes for hosting VM disk images using TCP, Unix
diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc
index 60a064b..1622571 100644
--- a/docs/system/qemu-block-drivers.rst.inc
+++ b/docs/system/qemu-block-drivers.rst.inc
@@ -547,75 +547,6 @@ also available.  Here are some example of the older syntax:
   |qemu_system| linux2.img -hdb nbd:unix:/tmp/my_socket
   |qemu_system| -cdrom nbd:localhost:10809:exportname=debian-500-ppc-netinst
 
-
-
-Sheepdog disk images
-~~~~~~~~~~~~~~~~~~~~
-
-Sheepdog is a distributed storage system for QEMU.  It provides highly
-available block level storage volumes that can be attached to
-QEMU-based virtual machines.
-
-You can create a Sheepdog disk image with the command:
-
-.. parsed-literal::
-
-  qemu-img create sheepdog:///IMAGE SIZE
-
-where *IMAGE* is the Sheepdog image name and *SIZE* is its
-size.
-
-To import the existing *FILENAME* to Sheepdog, you can use a
-convert command.
-
-.. parsed-literal::
-
-  qemu-img convert FILENAME sheepdog:///IMAGE
-
-You can boot from the Sheepdog disk image with the command:
-
-.. parsed-literal::
-
-  |qemu_system| sheepdog:///IMAGE
-
-You can also create a snapshot of the Sheepdog image like qcow2.
-
-.. parsed-literal::
-
-  qemu-img snapshot -c TAG sheepdog:///IMAGE
-
-where *TAG* is a tag name of the newly created snapshot.
-
-To boot from the Sheepdog snapshot, specify the tag name of the
-snapshot.
-
-.. parsed-literal::
-
-  |qemu_system| sheepdog:///IMAGE#TAG
-
-You can create a cloned image from the existing snapshot.
-
-.. parsed-literal::
-
-  qemu-img create -b sheepdog:///BASE#TAG sheepdog:///IMAGE
-
-where *BASE* is an image name of the source snapshot and *TAG*
-is its tag name.
-
-You can use an unix socket instead of an inet socket:
-
-.. parsed-literal::
-
-  |qemu_system| sheepdog+unix:///IMAGE?socket=PATH
-
-If the Sheepdog daemon doesn't run on the local host, you need to
-specify one of the Sheepdog servers to connect to.
-
-.. parsed-literal::
-
-  qemu-img create sheepdog://HOSTNAME:PORT/IMAGE SIZE
-  |qemu_system| sheepdog://HOSTNAME:PORT/IMAGE
-
 iSCSI LUNs
 ~~~~~~~~~~
 
diff --git a/docs/system/removed-features.rst b/docs/system/removed-features.rst
index f49737c..51a79b3 100644
--- a/docs/system/removed-features.rst
+++ b/docs/system/removed-features.rst
@@ -474,3 +474,10 @@ VXHS backend (removed in 5.1)
 '''''''''''''''''''''''''''''
 
 The VXHS code did not compile since v2.12.0. It was removed in 5.1.
+
+``sheepdog`` driver (removed in 6.0)
+''''''''''''''''''''''''''''''''''''
+
+The corresponding upstream server project is no longer maintained.
+Users are recommended to switch to an alternative distributed block
+device driver such as RBD.
diff --git a/meson.build b/meson.build
index 40e8f01..eeb82a4 100644
--- a/meson.build
+++ b/meson.build
@@ -2634,7 +2634,6 @@ if have_block
   summary_info += {'vvfat support':     config_host.has_key('CONFIG_VVFAT')}
   summary_info += {'qed support':       config_host.has_key('CONFIG_QED')}
   summary_info += {'parallels support': config_host.has_key('CONFIG_PARALLELS')}
-  summary_info += {'sheepdog support':  config_host.has_key('CONFIG_SHEEPDOG')}
   summary_info += {'FUSE exports':      fuse.found()}
 endif
 summary(summary_info, bool_yn: true, section: 'Block layer support')
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 6d22792..2ea2941 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2818,7 +2818,6 @@
             'luks', 'nbd', 'nfs', 'null-aio', 'null-co', 'nvme', 'parallels',
             'preallocate', 'qcow', 'qcow2', 'qed', 'quorum', 'raw', 'rbd',
             { 'name': 'replication', 'if': 'defined(CONFIG_REPLICATION)' },
-            'sheepdog',
             'ssh', 'throttle', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat' ] }
 
 ##
@@ -3652,26 +3651,6 @@
             '*server': ['InetSocketAddressBase'] } }
 
 ##
-# @BlockdevOptionsSheepdog:
-#
-# Driver specific block device options for sheepdog
-#
-# @vdi: Virtual disk image name
-# @server: The Sheepdog server to connect to
-# @snap-id: Snapshot ID
-# @tag: Snapshot tag name
-#
-# Only one of @snap-id and @tag may be present.
-#
-# Since: 2.9
-##
-{ 'struct': 'BlockdevOptionsSheepdog',
-  'data': { 'server': 'SocketAddress',
-            'vdi': 'str',
-            '*snap-id': 'uint32',
-            '*tag': 'str' } }
-
-##
 # @ReplicationMode:
 #
 # An enumeration of replication modes.
@@ -4037,7 +4016,6 @@
       'rbd':        'BlockdevOptionsRbd',
       'replication': { 'type': 'BlockdevOptionsReplication',
                        'if': 'defined(CONFIG_REPLICATION)' },
-      'sheepdog':   'BlockdevOptionsSheepdog',
       'ssh':        'BlockdevOptionsSsh',
       'throttle':   'BlockdevOptionsThrottle',
       'vdi':        'BlockdevOptionsGenericFormat',
@@ -4497,74 +4475,6 @@
 
 
 ##
-# @SheepdogRedundancyType:
-#
-# @full: Create a fully replicated vdi with x copies
-# @erasure-coded: Create an erasure coded vdi with x data strips and
-#                 y parity strips
-#
-# Since: 2.12
-##
-{ 'enum': 'SheepdogRedundancyType',
-  'data': [ 'full', 'erasure-coded' ] }
-
-##
-# @SheepdogRedundancyFull:
-#
-# @copies: Number of copies to use (between 1 and 31)
-#
-# Since: 2.12
-##
-{ 'struct': 'SheepdogRedundancyFull',
-  'data': { 'copies': 'int' }}
-
-##
-# @SheepdogRedundancyErasureCoded:
-#
-# @data-strips: Number of data strips to use (one of {2,4,8,16})
-# @parity-strips: Number of parity strips to use (between 1 and 15)
-#
-# Since: 2.12
-##
-{ 'struct': 'SheepdogRedundancyErasureCoded',
-  'data': { 'data-strips': 'int',
-            'parity-strips': 'int' }}
-
-##
-# @SheepdogRedundancy:
-#
-# Since: 2.12
-##
-{ 'union': 'SheepdogRedundancy',
-  'base': { 'type': 'SheepdogRedundancyType' },
-  'discriminator': 'type',
-  'data': { 'full': 'SheepdogRedundancyFull',
-            'erasure-coded': 'SheepdogRedundancyErasureCoded' } }
-
-##
-# @BlockdevCreateOptionsSheepdog:
-#
-# Driver specific image creation options for Sheepdog.
-#
-# @location: Where to store the new image file
-# @size: Size of the virtual disk in bytes
-# @backing-file: File name of a base image
-# @preallocation: Preallocation mode for the new image (default: off;
-#                 allowed values: off, full)
-# @redundancy: Redundancy of the image
-# @object-size: Object size of the image
-#
-# Since: 2.12
-##
-{ 'struct': 'BlockdevCreateOptionsSheepdog',
-  'data': { 'location':         'BlockdevOptionsSheepdog',
-            'size':             'size',
-            '*backing-file':    'str',
-            '*preallocation':   'PreallocMode',
-            '*redundancy':      'SheepdogRedundancy',
-            '*object-size':     'size' } }
-
-##
 # @BlockdevCreateOptionsSsh:
 #
 # Driver specific image creation options for SSH.
@@ -4687,7 +4597,6 @@
       'qcow2':          'BlockdevCreateOptionsQcow2',
       'qed':            'BlockdevCreateOptionsQed',
       'rbd':            'BlockdevCreateOptionsRbd',
-      'sheepdog':       'BlockdevCreateOptionsSheepdog',
       'ssh':            'BlockdevCreateOptionsSsh',
       'vdi':            'BlockdevCreateOptionsVdi',
       'vhdx':           'BlockdevCreateOptionsVhdx',
@@ -5322,7 +5231,7 @@
 #
 # Notes: In transaction, if @name is empty, or any snapshot matching @name
 #        exists, the operation will fail. Only some image formats support it,
-#        for example, qcow2, rbd, and sheepdog.
+#        for example, qcow2, and rbd.
 #
 # Since: 1.7
 ##
diff --git a/qapi/transaction.json b/qapi/transaction.json
index 15ddebd..894258d 100644
--- a/qapi/transaction.json
+++ b/qapi/transaction.json
@@ -112,10 +112,10 @@
 #
 # On failure, the original disks pre-snapshot attempt will be used.
 #
-# For internal snapshots, the dictionary contains the device and the snapshot's
-# name.  If an internal snapshot matching name already exists, the request will
-# be rejected.  Only some image formats support it, for example, qcow2, rbd,
-# and sheepdog.
+# For internal snapshots, the dictionary contains the device and the
+# snapshot's name.  If an internal snapshot matching name already exists,
+# the request will be rejected.  Only some image formats support it, for
+# example, qcow2, and rbd,
 #
 # On failure, qemu will try delete the newly created internal snapshot in the
 # transaction.  When an I/O error occurs during deletion, the user needs to fix
diff --git a/tests/qemu-iotests/005 b/tests/qemu-iotests/005
index 40e64a9..ba37754 100755
--- a/tests/qemu-iotests/005
+++ b/tests/qemu-iotests/005
@@ -52,11 +52,6 @@ if [ "$IMGFMT" = "vpc" ]; then
     _notrun "image format $IMGFMT does not support large image sizes"
 fi
 
-# sheepdog image is limited to 4TB, so we can't test it here
-if [ "$IMGPROTO" = "sheepdog" ]; then
-    _notrun "image protocol $IMGPROTO does not support large image sizes"
-fi
-
 # Sanity check: For raw, we require a file system that permits the creation
 # of a HUGE (but very sparse) file. Check we can create it before continuing.
 if [ "$IMGFMT" = "raw" ]; then
diff --git a/tests/qemu-iotests/025 b/tests/qemu-iotests/025
index da77ed3..80686a3 100755
--- a/tests/qemu-iotests/025
+++ b/tests/qemu-iotests/025
@@ -39,7 +39,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 . ./common.pattern
 
 _supported_fmt raw qcow2 qed luks
-_supported_proto file sheepdog rbd nfs fuse
+_supported_proto file rbd nfs fuse
 
 echo "=== Creating image"
 echo
diff --git a/tests/qemu-iotests/check b/tests/qemu-iotests/check
index d1c87ce..08f5136 100755
--- a/tests/qemu-iotests/check
+++ b/tests/qemu-iotests/check
@@ -65,8 +65,7 @@ def make_argparser() -> argparse.ArgumentParser:
         mg.add_argument('-' + fmt, dest='imgfmt', action='store_const',
                         const=fmt, help=f'test {fmt}')
 
-    protocol_list = ['file', 'rbd', 'sheepdog', 'nbd', 'ssh', 'nfs',
-                     'fuse']
+    protocol_list = ['file', 'rbd', 'nbd', 'ssh', 'nfs', 'fuse']
     g_prt = p.add_argument_group(
         '  image protocol options',
         'The following options set the IMGPROTO environment variable. '
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 7f49c97..cbbf6d7 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -641,10 +641,6 @@ _cleanup_test_img()
             rbd --no-progress rm "$TEST_DIR/t.$IMGFMT" > /dev/null
             ;;
 
-        sheepdog)
-            collie vdi delete "$TEST_DIR/t.$IMGFMT"
-            ;;
-
     esac
 }