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sheepdog: fix vdi object update after live snapshot

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sheepdog driver should decide a write request is COW or not based on inode
object which is active when the write request is issued.

Example of wrong inode update path in the previous driver:
1. drier issues an ordinal write request to an existing object
2. user creates a snapshot of the VDI before the write request is completed
3. the respones for the request is RDONLY, because the VDI is already a snapshot
4. the driver reload an inode object of the new active VDI, then issues a write
   request again
5. the second write request can be completed
6. driver decide the request is COW or not with the below conditional branch:
   	  if (s->inode.data_vdi_id[idx] != s->inode.vdi_id) {
7. the ID of the written object and VID of the new active VDI is different, so
   the driver updates data_vdi_id[idx] and writes inode object
8. the existing object cannot be seen by the new active VDI, it results object
   leaking

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Liu Yuan <namei.unix@gmail.com>
Cc: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Hitoshi Mitake 2014-06-06 13:35:11 +09:00 committed by Stefan Hajnoczi
parent 405a27640b
commit b544c1aba8
1 changed files with 23 additions and 17 deletions
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40
block/sheepdog.c
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@ -282,6 +282,7 @@ typedef struct AIOReq {
unsigned int data_len;
uint8_t flags;
uint32_t id;
bool create;
QLIST_ENTRY(AIOReq) aio_siblings;
} AIOReq;
@ -405,7 +406,7 @@ static const char * sd_strerror(int err)
static inline AIOReq *alloc_aio_req(BDRVSheepdogState *s, SheepdogAIOCB *acb,
uint64_t oid, unsigned int data_len,
uint64_t offset, uint8_t flags,
uint64_t offset, uint8_t flags, bool create,
uint64_t base_oid, unsigned int iov_offset)
{
AIOReq *aio_req;
@ -419,6 +420,7 @@ static inline AIOReq *alloc_aio_req(BDRVSheepdogState *s, SheepdogAIOCB *acb,
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;
@ -667,8 +669,8 @@ static int do_req(int sockfd, AioContext *aio_context, SheepdogReq *hdr,
}
static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
struct iovec *iov, int niov, bool create,
enum AIOCBState aiocb_type);
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);
@ -701,7 +703,7 @@ static void coroutine_fn send_pending_req(BDRVSheepdogState *s, uint64_t oid)
/* move aio_req from pending list to inflight one */
QLIST_REMOVE(aio_req, aio_siblings);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov, false,
add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
acb->aiocb_type);
}
}
@ -800,7 +802,7 @@ static void coroutine_fn aio_read_response(void *opaque)
}
idx = data_oid_to_idx(aio_req->oid);
if (s->inode.data_vdi_id[idx] != s->inode.vdi_id) {
if (aio_req->create) {
/*
* If the object is newly created one, we need to update
* the vdi object (metadata object). min_dirty_data_idx
@ -1120,8 +1122,8 @@ out:
}
static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
struct iovec *iov, int niov, bool create,
enum AIOCBState aiocb_type)
struct iovec *iov, int niov,
enum AIOCBState aiocb_type)
{
int nr_copies = s->inode.nr_copies;
SheepdogObjReq hdr;
@ -1132,6 +1134,7 @@ static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
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;
if (!nr_copies) {
error_report("bug");
@ -1324,6 +1327,7 @@ static bool check_simultaneous_create(BDRVSheepdogState *s, AIOReq *aio_req)
DPRINTF("simultaneous create to %" PRIx64 "\n", aio_req->oid);
aio_req->flags = 0;
aio_req->base_oid = 0;
aio_req->create = false;
QLIST_REMOVE(aio_req, aio_siblings);
QLIST_INSERT_HEAD(&s->pending_aio_head, aio_req, aio_siblings);
return true;
@ -1336,7 +1340,8 @@ static bool check_simultaneous_create(BDRVSheepdogState *s, AIOReq *aio_req)
static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req)
{
SheepdogAIOCB *acb = aio_req->aiocb;
bool create = false;
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)) {
@ -1354,17 +1359,17 @@ static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req)
aio_req->base_oid = vid_to_data_oid(s->inode.data_vdi_id[idx], idx);
aio_req->flags |= SD_FLAG_CMD_COW;
}
create = true;
aio_req->create = true;
}
out:
if (is_data_obj(aio_req->oid)) {
add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov, create,
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, false, AIOCB_WRITE_UDATA);
add_aio_request(s, aio_req, &iov, 1, AIOCB_WRITE_UDATA);
}
}
@ -1877,9 +1882,9 @@ static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
iov.iov_base = &s->inode;
iov.iov_len = sizeof(s->inode);
aio_req = alloc_aio_req(s, acb, vid_to_vdi_oid(s->inode.vdi_id),
data_len, offset, 0, 0, offset);
data_len, offset, 0, false, 0, offset);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
add_aio_request(s, aio_req, &iov, 1, false, AIOCB_WRITE_UDATA);
add_aio_request(s, aio_req, &iov, 1, AIOCB_WRITE_UDATA);
acb->aio_done_func = sd_finish_aiocb;
acb->aiocb_type = AIOCB_WRITE_UDATA;
@ -2078,7 +2083,8 @@ static int coroutine_fn sd_co_rw_vector(void *p)
DPRINTF("new oid %" PRIx64 "\n", oid);
}
aio_req = alloc_aio_req(s, acb, oid, len, offset, flags, old_oid, done);
aio_req = alloc_aio_req(s, acb, oid, len, offset, flags, create,
old_oid, done);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
if (create) {
@ -2087,7 +2093,7 @@ static int coroutine_fn sd_co_rw_vector(void *p)
}
}
add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov, create,
add_aio_request(s, aio_req, acb->qiov->iov, acb->qiov->niov,
acb->aiocb_type);
done:
offset = 0;
@ -2167,9 +2173,9 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
acb->aio_done_func = sd_finish_aiocb;
aio_req = alloc_aio_req(s, acb, vid_to_vdi_oid(s->inode.vdi_id),
0, 0, 0, 0, 0);
0, 0, 0, false, 0, 0);
QLIST_INSERT_HEAD(&s->inflight_aio_head, aio_req, aio_siblings);
add_aio_request(s, aio_req, NULL, 0, false, acb->aiocb_type);
add_aio_request(s, aio_req, NULL, 0, acb->aiocb_type);
qemu_coroutine_yield();
return acb->ret;