Current bs_sheepdog.c doesn't mock the behavior of QEMU's sheepdog driver in a correct manner when it opens snapshot VDIs. It treats the snapshot VDIs as read-only disks, but this behavior is different from the QEMU's driver. This patch lets bs_sheepdog.c mock the original behavior (delete an original VDI of the snapshot -> create a new non snapshot VDI based on the snapshot and open it). This patch also removes confusing notations of --backing-store option of bs_sheepdog.c.
Signed-off-by: Hitoshi Mitake <[email protected]> --- usr/bs_sheepdog.c | 109 +++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 76 insertions(+), 33 deletions(-) diff --git a/usr/bs_sheepdog.c b/usr/bs_sheepdog.c index 4f7cde0..11ddce6 100644 --- a/usr/bs_sheepdog.c +++ b/usr/bs_sheepdog.c @@ -622,8 +622,11 @@ static int reload_inode(struct sheepdog_access_info *ai) if (ret) return -1; - read_object(ai, (char *)&ai->inode, vid_to_vdi_oid(vid), - ai->inode.nr_copies, SD_INODE_SIZE, 0); + ret = read_object(ai, (char *)&ai->inode, vid_to_vdi_oid(vid), + ai->inode.nr_copies, SD_INODE_SIZE, 0); + if (ret) + return -1; + return 0; } @@ -917,9 +920,9 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags) enum { EXPECT_PROTO, EXPECT_PATH, - EXPECT_VDI, - EXPECT_HOST_OR_PORT, + EXPECT_HOST, EXPECT_PORT, + EXPECT_VDI, EXPECT_TAG_OR_SNAP, EXPECT_NOTHING, } parse_state = EXPECT_PROTO; @@ -942,9 +945,6 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags) * tcp:<host>:<port>:<vdi> * tcp:<host>:<port>:<vdi>:<tag> * tcp:<host>:<port>:<vdi>:<snapid> - * tcp:<port>:<vdi> - * tcp:<port>:<vdi>:<tag> - * tcp:<port>:<vdi>:<snapid> */ result = strtok_r(filename, ":", &saveptr); @@ -957,7 +957,7 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags) parse_state = EXPECT_PATH; } else if (!strcmp("tcp", result)) { ai->is_unix = 0; - parse_state = EXPECT_HOST_OR_PORT; + parse_state = EXPECT_HOST; } else { eprintf("unknown protocol of sheepdog vdi:"\ " %s\n", result); @@ -968,26 +968,14 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags) strncpy(ai->uds_path, result, UNIX_PATH_MAX); parse_state = EXPECT_VDI; break; - case EXPECT_HOST_OR_PORT: - len = strlen(result); - for (i = 0; i < len; i++) { - if (!isdigit(result[i])) { - /* result is a hostname */ - strncpy(ai->hostname, result, - HOST_NAME_MAX); - parse_state = EXPECT_PORT; - goto next_token; - } - } - - /* result is a port, use localhost as hostname */ - strncpy(ai->hostname, "localhost", strlen("localhost")); -set_port: + case EXPECT_HOST: + strncpy(ai->hostname, result, HOST_NAME_MAX); + parse_state = EXPECT_PORT; + break; + case EXPECT_PORT: ai->port = atoi(result); parse_state = EXPECT_VDI; break; - case EXPECT_PORT: - goto set_port; case EXPECT_VDI: strncpy(vdi_name, result, SD_MAX_VDI_LEN); parse_state = EXPECT_TAG_OR_SNAP; @@ -1017,8 +1005,6 @@ trans_to_expect_nothing: parse_state); exit(1); } - -next_token:; } while ((result = strtok_r(NULL, ":", &saveptr)) != NULL); if (parse_state != EXPECT_NOTHING && @@ -1039,7 +1025,8 @@ next_token:; else dprintf("snapid: %d\n", snapid); - ai->is_snapshot = !(snapid == -1) && strlen(tag); + dprintf("VDI name: %s\n", vdi_name); + ai->is_snapshot = !(snapid == -1) || strlen(tag); ret = find_vdi_name(ai, vdi_name, snapid == -1 ? 0 : snapid, tag, &vid, ai->is_snapshot); if (ret) @@ -1087,6 +1074,53 @@ static void set_medium_error(int *result, uint8_t *key, uint16_t *asc) *asc = ASC_READ_ERROR; } +static int create_branch(struct sheepdog_access_info *ai) +{ + struct sheepdog_vdi_req hdr; + struct sheepdog_vdi_rsp *rsp = (struct sheepdog_vdi_rsp *)&hdr; + unsigned int wlen = 0, rlen; + int ret; + + hdr.opcode = SD_OP_DEL_VDI; + hdr.vdi_id = ai->inode.vdi_id; + hdr.flags = SD_FLAG_CMD_WRITE; + wlen = SD_MAX_VDI_LEN; + hdr.data_length = wlen; + + ret = do_req(ai, (struct sheepdog_req *)&hdr, ai->inode.name, + &wlen, &rlen); + if (ret) { + eprintf("deleting snapshot VDI for creating branch failed\n"); + return -1; + } + + memset(&hdr, 0, sizeof(hdr)); + hdr.opcode = SD_OP_NEW_VDI; + hdr.vdi_id = ai->inode.vdi_id; + + hdr.flags = SD_FLAG_CMD_WRITE; + wlen = SD_MAX_VDI_LEN; + hdr.data_length = wlen; + hdr.vdi_size = ai->inode.vdi_size; + ret = do_req(ai, (struct sheepdog_req *)&hdr, ai->inode.name, + &wlen, &rlen); + if (ret) { + eprintf("creating new VDI for creating branch failed\n"); + return -1; + } + + ret = read_object(ai, (char *)&ai->inode, vid_to_vdi_oid(rsp->vdi_id), + ai->inode.nr_copies, SD_INODE_SIZE, 0); + if (ret) { + eprintf("reloading new inode object failed"); + return -1; + } + + dprintf("creating branch from snapshot, new VDI ID: %x\n", rsp->vdi_id); + + return 0; +} + static void bs_sheepdog_request(struct scsi_cmd *cmd) { int ret = 0; @@ -1110,11 +1144,20 @@ static void bs_sheepdog_request(struct scsi_cmd *cmd) case WRITE_12: case WRITE_16: if (ai->is_snapshot) { - length = scsi_get_out_length(cmd); - ret = sd_io(ai, 1, scsi_get_out_buffer(cmd), - length, cmd->offset); - } else - ret = -1; + ret = create_branch(ai); + if (ret) { + eprintf("creating writable VDI from"\ + " snapshot failed\n"); + set_medium_error(&result, &key, &asc); + + return; + } + ai->is_snapshot = 0; + } + + length = scsi_get_out_length(cmd); + ret = sd_io(ai, 1, scsi_get_out_buffer(cmd), + length, cmd->offset); if (ret) set_medium_error(&result, &key, &asc); -- 1.7.10.4 -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
