diff options
| -rw-r--r-- | block/sheepdog.c | 54 |
1 files changed, 53 insertions, 1 deletions
diff --git a/block/sheepdog.c b/block/sheepdog.c index 77e21fdb7f..21a4edf15b 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -36,6 +36,7 @@ #define SD_OP_GET_VDI_INFO 0x14 #define SD_OP_READ_VDIS 0x15 #define SD_OP_FLUSH_VDI 0x16 +#define SD_OP_DEL_VDI 0x17 #define SD_FLAG_CMD_WRITE 0x01 #define SD_FLAG_CMD_COW 0x02 @@ -1666,6 +1667,43 @@ out: sd_finish_aiocb(acb); } +/* Delete current working VDI on the snapshot chain */ +static bool sd_delete(BDRVSheepdogState *s) +{ + unsigned int wlen = SD_MAX_VDI_LEN, rlen = 0; + SheepdogVdiReq hdr = { + .opcode = SD_OP_DEL_VDI, + .vdi_id = s->inode.vdi_id, + .data_length = wlen, + .flags = SD_FLAG_CMD_WRITE, + }; + SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr; + int fd, ret; + + fd = connect_to_sdog(s); + if (fd < 0) { + return false; + } + + ret = do_req(fd, (SheepdogReq *)&hdr, s->name, &wlen, &rlen); + closesocket(fd); + if (ret) { + return false; + } + switch (rsp->result) { + case SD_RES_NO_VDI: + error_report("%s was already deleted", s->name); + /* fall through */ + case SD_RES_SUCCESS: + break; + default: + error_report("%s, %s", sd_strerror(rsp->result), s->name); + return false; + } + + return true; +} + /* * Create a writable VDI from a snapshot */ @@ -1674,12 +1712,20 @@ static int sd_create_branch(BDRVSheepdogState *s) int ret, fd; uint32_t vid; char *buf; + bool deleted; dprintf("%" PRIx32 " is snapshot.\n", s->inode.vdi_id); buf = g_malloc(SD_INODE_SIZE); - ret = do_sd_create(s, s->name, s->inode.vdi_size, s->inode.vdi_id, &vid, 1); + /* + * Even If deletion fails, we will just create extra snapshot based on + * the workding VDI which was supposed to be deleted. So no need to + * false bail out. + */ + deleted = sd_delete(s); + ret = do_sd_create(s, s->name, s->inode.vdi_size, s->inode.vdi_id, &vid, + !deleted); if (ret) { goto out; } @@ -1995,6 +2041,12 @@ cleanup: return ret; } +/* + * We implement rollback(loadvm) operation to the specified snapshot by + * 1) switch to the snapshot + * 2) rely on sd_create_branch to delete working VDI and + * 3) create a new working VDI based on the speicified snapshot + */ static int sd_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) { BDRVSheepdogState *s = bs->opaque; |