glusterfs.git/xlators/cluster/afr/src, branch v3.11dev

afr: Avoid resetting event_gen when brick is always down

2017-01-13T02:54:02+00:00

Problem:
__afr_set_in_flight_sb_status(), which resets event_gen to zero, is
called if failed_subvols[i] is non-zero for any brick. But failed_subvols[i]
is true even if the brick was down *before* the transaction started.
Hence say if 1 brick is down in  a replica-3, every writev that comes
will trigger an inode refresh because of this resetting, as seen from
the no. of FSTATs in the profile info in the BZ.

Fix:
Reset event gen only if the brick was previously a valid read child and
the FOP failed on it the first time.

Also `s/afr_inode_read_subvol_reset/afr_inode_event_gen_reset` because
the function only resets event gen and not the data/metadata readable.

Change-Id: I603ae646cbde96995c35db77916e2ed80b602a91
BUG: 1409206
Signed-off-by: Ravishankar N 
Reviewed-on: http://review.gluster.org/16309
Smoke: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Pranith Kumar Karampuri 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

cluster/afr: Do not log of split-brain when there isn't one

2017-01-12T06:42:02+00:00

* Even on errors like ENOENT, AFR logs split-brain after
  read-txn refresh, introduced by commit a07ddd8f.
  This can be a cause of much panic and confusion and needs to be fixed.

* Also fixed this issue in write-txns.

* Fixed afr read txns to log about split-brain only after knowing that
  there is no split-brain choice configured.

* Removed code duplication

* Fixed incorrect passing of error code in afr_write_txn_refresh_done()
  (the function was passing -0 as errno to gf_msg().

Change-Id: I354f454ce5bf0e5f00bc27916eb597367cb7d927
BUG: 1411625
Signed-off-by: Krutika Dhananjay 
Reviewed-on: http://review.gluster.org/16362
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Ravishankar N 
Reviewed-by: Pranith Kumar Karampuri

ec: Invalidations in disperse volume should not update the stat

2017-01-06T05:12:18+00:00

Issue:
In disperse volume, the file is present across bricks, hence the stat
from one brick doesn't carry the valid size of the file. Therefore
the upcall from one brick updating the md-cache results in wrong size
being updated.

Fix:
If the notification is cache invalidation then, indicate md-cache that
the attributes is invalid.

BUG: 1410375
Change-Id: Id89d2283478e70b62b435a8891fffc86d2be8cb2
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/16329
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Xavier Hernandez 
CentOS-regression: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri

cluster/afr: Fix missing name indices due to EEXIST error

2016-12-27T11:53:04+00:00

PROBLEM:
Consider a volume with  granular-entry-heal and sharding enabled. When
a replica is down and a shard is created as part of a write, the name
index is correctly created under indices/entry-changes/.
Now when a read on the same region triggers another MKNOD, the fop
fails on the online bricks with EEXIST. By virtue of this being a
symmetric error, the failed_subvols[] array is reset to all zeroes.
Because of this, before post-op, the GF_XATTROP_ENTRY_OUT_KEY will be
set, causing the name index, which was created in the previous MKNOD
operation, to be wrongly deleted in THIS MKNOD operation.

FIX:
The ideal fix would have been for a transaction to delete the name
index ONLY if it knows it is the one that created the index in the first
place. This would involve gathering information as to whether THIS xattrop
created the index from individual bricks, aggregating their responses and
based on the various posisble combinations of responses, decide whether to
delete the index or not. This is rather complex. Simpler fix would be
for post-op to examine local->op_ret in the event of no failed_subvols
to figure out whether to delete the name index or not. This can occasionally
lead to creation of stale name indices but they won't be affecting the IO path
or mess with pending changelogs in any way and self-heal in its crawl of
"entry-changes" directory would take care to delete such indices.

Change-Id: Ic1b5257f4dc9c20cb740a866b9598cf785a1affa
BUG: 1408712
Signed-off-by: Krutika Dhananjay 
Reviewed-on: http://review.gluster.org/16286
Smoke: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

afr: use accused matrix instead of readable matrix for deciding heals

2016-12-27T06:34:02+00:00

Problem:
afr_replies_interpret() used the 'readable' matrix to trigger client
side heals after inode refresh. But for arbiter, readable is always
zero. So when `dd` is run with a data brick down, spurious data heals
are are triggered. These heals open an fd, causing eager lock to be
disabled (open fd count >1) in afr transactions, leading to extra FXATTROPS

Fix:
Use the accused matrix (derived from interpreting the afr pending
xattrs) to decide whether we can start heal or not.

Change-Id: Ibbd56c9aed6026de6ec42422e60293702aaf55f9
BUG: 1408395
Signed-off-by: Ravishankar N 
Reviewed-on: http://review.gluster.org/16277
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Smoke: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Pranith Kumar Karampuri

afr: Ignore event_generation checks post inode refresh for write txns

2016-12-22T11:06:31+00:00

Before http://review.gluster.org/#/c/15673/, after inode refresh, we
failed read txns in case of EIO or event_generation being zero. For
write transactions, the check was only for EIO. 15673 re-factored the
code to fail both read and write when event_generation=0. This seems to
have caused a regression as explained in the BZ.

This patch restores that behaviour in afr_txn_refresh_done().

Change-Id: Ib8e116506badce6f58b55827dbe403d95069d744
BUG: 1406224
Signed-off-by: Ravishankar N 
Reviewed-on: http://review.gluster.org/16205
Reviewed-by: Pranith Kumar Karampuri 
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System

cluster/afr: Fix per-txn optimistic changelog initialisation

2016-12-12T16:38:49+00:00

Incorrect initialisation of local->optimistic_change_log was leading
to skipped pre-op and post-op even when a brick didn't participate in
the txn because it was down.
The result - missing granular name index resulting in some entries
never getting healed.

FIX:
Initialise local->optimistic_change_log just before pre-op.

Also fixed granular entry heal to create the granular name index in
pre-op as opposed to post-op. This is to prevent loss of granular
information when during an entry txn, the good (src) brick goes
offline before the post-op is done. This would cause self-heal to
do conservative merge (since dirty xattr is the only information
available), which when granular-entry-heal is enabled, expects
granular indices, the lack of which can lead to loss of data in
the worst case.

Change-Id: Ia3ad716d6fb1821555f02180e86e8711a79f958d
BUG: 1402730
Signed-off-by: Krutika Dhananjay 
Reviewed-on: http://review.gluster.org/16075
Smoke: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

cluster/afr: Remove backward compatibility for locks with v1

2016-12-07T08:51:56+00:00

When we have cascading locks with same lk-owner there is a possibility for
a deadlock to happen. One example is as follows:

self-heal takes a lock in data-domain for big name with 256 chars of "aaaa...a"
and starts heal in a 3-way replication when brick-0 is offline and healing from
brick-1 to brick-2 is in progress. So this lock is active on brick-1 and
brick-2. Now brick-0 comes online and an operation wants to take full lock and
the lock is granted at brick-0 and it is waiting for lock on brick-1. As part
of entry healing it takes full locks on all the available bricks and then
proceeds with healing the entry. Now this lock will start waiting on brick-0
because some other operation already has a granted lock on it. This leads to a
deadlock. Operation is waiting for unlock on "aaaa..." by heal where as heal is
waiting for the operation to unlock on brick-0. Initially I thought this is
happening because healing is trying to take a lock on all the available bricks
instead of just the bricks that are participating in heal. But later realized
that same kind of deadlock can happen if a brick goes down after the heal
starts but comes back before it completes. So the essential problem is the
cascading locks with same lk-owner which were added for backward compatibility
with afr-v1 which can be safely removed now that versions with afr-v1 are
already EOL. This patch removes the compatibility with v1 which requires
cascading locks with same lk-owner.

In the next version we can make locking-scheme option a dummy and switch
completely to v2.

BUG: 1401404
Change-Id: Ic9afab8260f5ff4dff5329eb0429811bcb879079
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/16024
Smoke: Gluster Build System 
Reviewed-by: Ravishankar N 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

cluster/afr: Serialize conflicting locks on all subvols

2016-12-07T06:47:40+00:00

Problem:
1) When a blocking lock is issued and the parallel lock phase fails
on all subvolumes with EAGAIN, it is not switching to serialized
locking phase.
2) When quorum is enabled and locks fail partially it is better
to give errno returned by brick rather than the default
quorum errno.

Fix:
Handled this error case and changed op_errno to reflect the actual
errno in case of quorum error.

BUG: 1369077
Change-Id: Ifac2e4a13686e9fde601873012700966d56a7f31
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/15984
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Ravishankar N

afr: fix bug in passing child index in afr_inode_write_fill

2016-12-06T12:12:00+00:00

Change-Id: I7b70de317a5f15a3bf483ffe40b971143deddc11
BUG: 1401218
Signed-off-by: Ravishankar N 
Reviewed-on: http://review.gluster.org/16029
Reviewed-by: Pranith Kumar Karampuri 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System