path: root/tests/volume.rc
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authorPranith Kumar K <>2013-03-03 20:41:30 +0530
committerAnand Avati <>2013-04-02 18:59:21 -0700
commit6b393b3ab6799ede09f6d2b303e35b8bc505f465 (patch)
tree73e32a00c8cf5d2de850a0ec304bae3a759e2325 /tests/volume.rc
parent93175bd20eaacf51b98d67963a9372af52b83634 (diff)
cluster/afr: detect in-progress creation in lookup and return ENOENT
if any subvol returned ENOENT while parent entrylk lock was held, yield and return ENOENT for the entire lookup. This is how the issue happens: Multiple clients A, B and C are attempting 'mkdir -p /mnt/a/b/c' 1 Client A is in the middle of mkdir(/a). It has acquired lock. It has performed mkdir(/a) on one subvol, and second one is still in progress 2 Client B performs a lookup, sees directory /a on one, ENOENT on the other, succeeds lookup. 3 Client B performs lookup on /a/b on both subvols, both return ENOENT (one subvol because /a/b does not exist, another because /a itself does not exist) 4 Client B proceeds to mkdir /a/b. It obtains entrylk on inode=/a with basename=b on one subvol, but fails on other subvol as /a is yet to be created by Client A. 5 Client A finishes mkdir of /a on other subvol 6 Client C also attempts to create /a/b, lookup returns ENOENT on both subvols. 7 Client C tries to obtain entrylk on on inode=/a with basename=b, obtains on one subvol (where B had failed), and waits for B to unlock on other subvol. 8 Client B finishes mkdir() on one subvol with GFID-1 and completes transaction and unlocks 9 Client C gets the lock on the second subvol, At this stage second subvol already has /a/b created from Client B, but Client C does not check that in the middle of mkdir transaction 10 Client C attempts mkdir /a/b on both subvols. It succeeds on ONLY ONE (where Client B could not get lock because of missing parent /a dir) with GFID-2, and gets EEXIST from ONE subvol. This way we have /a/b in GFID mismatch. One subvol got GFID-1 because Client B performed transaction on only one subvol (because entrylk() could not be obtained on second subvol because of missing parent dir -- caused by premature/speculative succeeding of lookup() on /a when locks are detected). Other subvol gets GFID-2 from Client C because while it was waiting for entrylk() on both subvols, Client B was in the middle of creating mkdir() on only one subvol, and Client C does not "expect" this when it is between lock() and pre-op()/op() phase of the transaction. Original-author: Anand Avati <> Change-Id: Idca475dbbc2a51e09da6fa0f9e1e37148caef208 BUG: 860210 Signed-off-by: Pranith Kumar K <> Reviewed-on: Tested-by: Gluster Build System <> Reviewed-by: Anand Avati <>
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