This commit lets the sheepdog driver reject forms of filename below.
This is to avoid unintended deletion of working VDI when a snapshot is
given as a LUN.
* unix:<path_of_unix_domain_socket>:<vdi>:<tag>
* unix:<path_of_unix_domain_socket>:<vdi>:<snapid>
* tcp:<host>:<port>:<vdi>:<tag>
* tcp:<host>:<port>:<vdi>:<snapid>
In the case that a snapshot is given as a LUN by any of them above, the
sheepdog driver attempts to delete it then create a new writable VDI when
some data is being written to it. The deletion request contains name and
VDI ID of the snapshot. However, sheep daemon uses its name but ignores
VDI ID and, what is worse, the request contains neither snapshot ID nor
tag. So sheep daemon receiving the request interprets it as deletion of
working VDI, not snapshot. If there is working VDI with the same name,
it will be deleted unintentionally.
I decided not to fix the sheepdog driver to send snapshot ID or tag but
to let it reject snapshot as a LUN because, even if I fix it, creating
a new writable VDI will be failed when working VDI exists. If you want
workaround, use "dog vdi clone" command to create a new writable VDI from
snapshot then give the new VDI as a LUN.
Cc: Teruaki Ishizaki <ishizaki.teruaki@xxxxxxxxxxxxx>
Cc: Hitoshi Mitake <mitake.hitoshi@xxxxxxxxxxxxx>
Signed-off-by: Takashi Menjo <menjo.takashi@xxxxxxxxxxxxx>
---
usr/bs_sheepdog.c | 112 +-----------------------------------------------------
1 file changed, 2 insertions(+), 110 deletions(-)
diff --git a/usr/bs_sheepdog.c b/usr/bs_sheepdog.c
index fc91ad1..f702c12 100644
--- a/usr/bs_sheepdog.c
+++ b/usr/bs_sheepdog.c
@@ -273,9 +273,6 @@ struct sheepdog_access_info {
/* unix domain socket */
char uds_path[UNIX_PATH_MAX];
- /* if the opened VDI is a snapshot, write commands cannot be issued */
- int is_snapshot;
-
/*
* maximum length of fd_list_head: nr_iothreads + 1
* (+ 1 is for main thread)
@@ -1129,8 +1126,6 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags)
uint32_t vid = 0;
char *orig_filename;
- uint32_t snapid = -1;
- char tag[SD_MAX_VDI_TAG_LEN + 1];
char vdi_name[SD_MAX_VDI_LEN + 1];
char *saveptr = NULL, *result;
enum {
@@ -1139,11 +1134,9 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags)
EXPECT_HOST,
EXPECT_PORT,
EXPECT_VDI,
- EXPECT_TAG_OR_SNAP,
EXPECT_NOTHING,
} parse_state = EXPECT_PROTO;
- memset(tag, 0, sizeof(tag));
memset(vdi_name, 0, sizeof(vdi_name));
orig_filename = strdup(filename);
@@ -1156,11 +1149,7 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags)
* expected form of filename:
*
* unix:<path_of_unix_domain_socket>:<vdi>
- * unix:<path_of_unix_domain_socket>:<vdi>:<tag>
- * unix:<path_of_unix_domain_socket>:<vdi>:<snapid>
* tcp:<host>:<port>:<vdi>
- * tcp:<host>:<port>:<vdi>:<tag>
- * tcp:<host>:<port>:<vdi>:<snapid>
*/
result = strtok_r(filename, ":", &saveptr);
@@ -1205,21 +1194,6 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags)
break;
case EXPECT_VDI:
strncpy(vdi_name, result, SD_MAX_VDI_LEN);
- parse_state = EXPECT_TAG_OR_SNAP;
- break;
- case EXPECT_TAG_OR_SNAP:
- len = strlen(result);
- for (i = 0; i < len; i++) {
- if (!isdigit(result[i])) {
- /* result is a tag */
- strncpy(tag, result,
- SD_MAX_VDI_TAG_LEN);
- goto trans_to_expect_nothing;
- }
- }
-
- snapid = atoi(result);
-trans_to_expect_nothing:
parse_state = EXPECT_NOTHING;
break;
case EXPECT_NOTHING:
@@ -1235,8 +1209,7 @@ trans_to_expect_nothing:
}
} while ((result = strtok_r(NULL, ":", &saveptr)) != NULL);
- if (parse_state != EXPECT_NOTHING &&
- parse_state != EXPECT_TAG_OR_SNAP) {
+ if (parse_state != EXPECT_NOTHING) {
eprintf("invalid VDI path of sheepdog: %s (state: %d)\n",
orig_filename, parse_state);
ret = -1;
@@ -1269,15 +1242,8 @@ trans_to_expect_nothing:
close(fd); /* we don't need this connection */
- if (snapid == -1)
- dprintf("tag: %s\n", tag);
- else
- dprintf("snapid: %d\n", snapid);
-
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);
+ ret = find_vdi_name(ai, vdi_name, 0, "", &vid, 0);
if (ret)
goto out;
@@ -1326,69 +1292,6 @@ 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, need_reload = 0;
-
- ret = pthread_rwlock_wrlock(&ai->inode_lock);
- if (ret) {
- eprintf("failed to get inode lock %s\n", strerror(ret));
- return -1;
- }
-
- if (!ai->is_snapshot)
- /* check again the snapshot flag to avoid race condition */
- goto out;
-
- memset(&hdr, 0, sizeof(hdr));
- hdr.opcode = SD_OP_DEL_VDI;
- hdr.vdi_id = ai->inode.vdi_id;
- hdr.flags = SD_FLAG_CMD_WRITE;
- wlen = SD_MAX_VDI_LEN;
- rlen = 0;
- 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");
- goto out;
- }
-
- 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;
- rlen = 0;
- 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");
- goto out;
- }
-
- ret = read_object(ai, (char *)&ai->inode, vid_to_vdi_oid(rsp->vdi_id),
- ai->inode.nr_copies, SD_INODE_SIZE, 0, &need_reload);
- if (ret) {
- eprintf("reloading new inode object failed");
- goto out;
- }
-
- ai->is_snapshot = 0;
- dprintf("creating branch from snapshot, new VDI ID: %x\n", rsp->vdi_id);
-out:
- pthread_rwlock_unlock(&ai->inode_lock);
-
- return ret;
-}
-
struct inflight_thread {
unsigned long min_idx, max_idx;
struct list_head list;
@@ -1453,17 +1356,6 @@ static void bs_sheepdog_request(struct scsi_cmd *cmd)
case WRITE_10:
case WRITE_12:
case WRITE_16:
- if (ai->is_snapshot) {
- ret = create_branch(ai);
- if (ret) {
- eprintf("creating writable VDI from"\
- " snapshot failed\n");
- set_medium_error(&result, &key, &asc);
-
- break;
- }
- }
-
length = scsi_get_out_length(cmd);
myself.min_idx = cmd->offset / object_size;
--
2.7.4
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