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authorKrutika Dhananjay <kdhananj@redhat.com>2018-10-17 14:26:14 +0530
committerRaghavendra Bhat <raghavendra@redhat.com>2018-10-18 16:04:19 +0000
commit15c99765e0597b835d92560fc926067313848c88 (patch)
tree18b357c11434d0003e2f0cb492d97b5c247b02bc /xlators/storage/posix/src/posix-helpers.c
parent273c895747d073d43a1e8617218d4bfd2cf13f18 (diff)
storage/posix: Do not fail entry creation fops if gfid handle already exists
PROBLEM: tests/bugs/shard/bug-1251824.t fails occasionally with EIO due to gfid mismatch across replicas on the same shard when dd is executed. CAUSE: Turns out this is due to a race between posix_mknod() and posix_lookup(). posix mknod does 3 operations, among other things: 1. creation of the entry itself under its parent directory 2. setting the gfid xattr on the file, and 3. creating the gfid link under .glusterfs. Consider a case where the thread doing posix_mknod() (initiated by shard) has executed steps 1 and 2 and is on its way to executing 3. And a parallel LOOKUP from another thread on noting that loc->inode->gfid is NULL, tries to perform gfid_heal where it attempts to create the gfid link under .glusterfs and succeeds. As a result, posix_gfid_set() through MKNOD (step 3) fails with EEXIST. In the older code, MKNOD under such conditions was NOT being treated as a failure. But commit e37ee6d changes this behavior by failing MKNOD, causing the entry creation to be undone in posix_mknod() (it's another matter that the stale gfid handle gets left behind if lookup has gone ahead and gfid-healed it). All of this happens on only one replica while on the other MKNOD succeeds. Now if a parallel write causes shard translator to send another MKNOD of the same shard (shortly after AFR releases entrylk from the first MKNOD), the file is created on the other replica too, although with a new gfid (since "gfid-req" that is passed now is a new UUID. This leads to a gfid-mismatch across the replicas. FIX: The solution is to not fail MKNOD (or any other entry fop for that matter that does posix_gfid_set()) if the .glusterfs link creation fails with EEXIST. Change-Id: I84a5e54d214b6c47ed85671a880bb1c767a29f4d fixes: bz#1638453 Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>
Diffstat (limited to 'xlators/storage/posix/src/posix-helpers.c')
-rw-r--r--xlators/storage/posix/src/posix-helpers.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/xlators/storage/posix/src/posix-helpers.c b/xlators/storage/posix/src/posix-helpers.c
index 4c3f064..9bb3b99 100644
--- a/xlators/storage/posix/src/posix-helpers.c
+++ b/xlators/storage/posix/src/posix-helpers.c
@@ -962,7 +962,7 @@ posix_gfid_set(xlator_t *this, const char *path, loc_t *loc, dict_t *xattr_req,
if (sys_lstat(path, &stat) != 0) {
ret = -1;
gf_msg(this->name, GF_LOG_ERROR, errno, P_MSG_LSTAT_FAILED,
- "lsatat on %s failed", path);
+ "lstat on %s failed", path);
goto out;
}