glusterfs.git/xlators/cluster/afr/src/afr.h, branch v3.7.17

cluster/afr: Prevent split-brain when bricks are brought off and on in cyclic order

2016-08-22T10:05:08+00:00

        Backport of: http://review.gluster.org/15080

When the bricks are brought offline and then online in cyclic
order while writes are in progress on a file, thanks to inode
refresh in write txns, AFR will mostly fail the write attempt
when the only good copy is offline. However, there is still a
remote possibility that the file will run into split-brain if
the brick that has the lone good copy goes offline *after* the
inode refresh but *before* the write txn completes (I call it
in-flight split-brain in the patch for ease of reference),
requiring intervention from admin to resolve the split-brain
before the IO can resume normally on the file. To get around this,
the patch does the following things:
i) retains the dirty xattrs on the file
ii) avoids marking the last of the good copies as bad (or accused)
    in case it is the one to go down during the course of a write.
iii) fails that particular write with the appropriate errno.

This way, we still have one good copy left despite the split-brain situation
which when it is back online, will be chosen as source to do the heal.

Change-Id: I7c13c6ddd5b8fe88b0f2684e8ce5f4a9c3a24a08
BUG: 1367270
Signed-off-by: Krutika Dhananjay 
Reviewed-on: http://review.gluster.org/15222
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Oleksandr Natalenko 
Reviewed-by: Pranith Kumar Karampuri

afr: some coverity fixes

2016-07-28T13:54:36+00:00

Backport of http://review.gluster.org/#/c/14895/

Thanks to Krutika for a cleaner way to track inode refs in
afr_set_split_brain_choice().

Change-Id: I2d968d05b815ad764b7e3f8aa9ad95a792b3c1df
BUG: 1360549
Signed-off-by: Ravishankar N 
Reviewed-on: http://review.gluster.org/15017
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Krutika Dhananjay 
Reviewed-by: Pranith Kumar Karampuri

cluster/afr: Unwind xdata_rsp even in case of failures

2016-06-03T13:24:00+00:00

DHT expects GF_PREOP_CHECK_FAILED to be present in xdata_rsp in case of mkdir
failures because of stale layout. But AFR was unwinding null xdata_rsp in case
of failures. This was leading to mkdir failures just after remove-brick. Unwind
the xdata_rsp in case of failures to make sure the response from brick reaches
dht.

 >BUG: 1340623
 >Change-Id: Idd3f7b95730e8ea987b608e892011ff190e181d1
 >Signed-off-by: Pranith Kumar K 
 >Reviewed-on: http://review.gluster.org/14553
 >NetBSD-regression: NetBSD Build System 
 >Reviewed-by: Ravishankar N 
 >Smoke: Gluster Build System 
 >CentOS-regression: Gluster Build System 
 >Reviewed-by: Anuradha Talur 
 >Reviewed-by: Krutika Dhananjay 

BUG: 1340992
Change-Id: I2641d35a851be692aa223dfea5d082245ac6c2bc
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/14633
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Smoke: Gluster Build System

cluster/afr: Refresh inode for inode-write fops in need

2016-05-29T11:13:38+00:00

Problem:
If a named fresh-lookup is done on an loc and the fop fails on one of the
bricks or not sent on one of the bricks, but by the time response comes to afr,
if the brick is up, 'can_interpret' will be set to false in afr_lookup_done(),
this will lead to inode-ctx for that inode to be not set, this can lead to EIO
in case of a transaction as it depends on 'readable' array to be available by
that point.

Fix:
Refresh inode for inode-write fops for the ctx to be set if it is not already
done at the time of named fresh-lookup or if the file is in split-brain where
we need to perform one more refresh before failing the fop to check if the file
is still in split-brain or not.

 >BUG: 1336612
 >Change-Id: I5c50b62c8de06129b8516039f7c252e5008c47a5
 >Signed-off-by: Pranith Kumar K 
 >Reviewed-on: http://review.gluster.org/14368
 >Smoke: Gluster Build System 
 >NetBSD-regression: NetBSD Build System 
 >Reviewed-by: Ravishankar N 
 >CentOS-regression: Gluster Build System 
 >Backport of http://review.gluster.org/14545

BUG: 1337831
Change-Id: If4465ab8fc506e1f905b623b82a53bdab8f5cffd
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/14453
NetBSD-regression: NetBSD Build System 
Reviewed-by: Ravishankar N 
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System

afr: propagate child up event after timeout

2016-04-28T04:44:50+00:00

Backport of: http://review.gluster.org/11113

Problem: During mount, afr waits for response from all its children before
notifying the parent xlator. In a 1x2 replica volume , if one of the nodes is
down, the mount will hang for more than a minute until child down is received
from the client xlator for that node.

Fix:
When parent up is received by afr, start a 10 second timer. In the timer call
back, if we receive a successful child up from atleast one brick, propagate the
event to the parent xlator.

Change-Id: I31e57c8802c1a03a4a5d581ee4ab82f3a9c8799d
BUG: 1330855
Signed-off-by: Ravishankar N 
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/14088
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

cluster/afr: Fix spurious entries in heal info

2016-04-20T16:46:52+00:00

Problem:
Locking schemes in afr-v1 were locking the directory/file completely during
self-heal. Newer schemes of locking don't require Full directory, file locking.
But afr-v2 still has compatibility code to work-well with older clients, where
in entry-self-heal it takes a lock on a special 256 character name which can't
be created on the fs. Similarly for data self-heal there used to be a lock on
(LLONG_MAX-2, 1). Old locking scheme requires heal info to take sh-domain locks
before examining heal-state.  If it doesn't take sh-domain locks, then there is
a possibility of heal-info hanging till self-heal completes because of
compatibility locks.  But the problem with heal-info taking sh-domain locks is
that if two heal-info or shd, heal-info try to inspect heal state in parallel
using trylocks on sh-domain, there is a possibility that both of them assuming
a heal is in progress. This was leading to spurious entries being shown in
heal-info.

Fix:
As long as there is afr-v1 way of locking, we can't fix this problem with
simple solutions.  If we know that the cluster is running newer versions of
locking schemes, in those cases we can give accurate information in heal-info.
So introduce a new option called 'locking-scheme' which if it is 'granular'
will give correct information in heal-info. Not only that, Extra network hops
for taking compatibility locks, sh-domain locks in heal info will not be
necessary anymore. Thus it improves performance.

 >BUG: 1322850
 >Change-Id: Ia563c5f096b5922009ff0ec1c42d969d55d827a3
 >Signed-off-by: Pranith Kumar K 
 >Reviewed-on: http://review.gluster.org/13873
 >Smoke: Gluster Build System 
 >NetBSD-regression: NetBSD Build System 
 >CentOS-regression: Gluster Build System 
 >Reviewed-by: Ashish Pandey 
 >Reviewed-by: Anuradha Talur 
 >Reviewed-by: Krutika Dhananjay 
 >(cherry picked from commit b6a0780d86e7c6afe7ae0d9a87e6fe5c62b4d792)

Change-Id: If7eee18843b48bbeff4c1355c102aa572b2c155a
BUG: 1294675
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/14039
Reviewed-by: Krutika Dhananjay 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

cluster/afr: Use parallel dir scan functionality

2016-04-17T14:11:23+00:00

 >BUG: 1221737
 >Change-Id: I0ed71a72f0e33bd733723e00a01cf28378c5534e
 >Signed-off-by: Pranith Kumar K 
 >Reviewed-on: http://review.gluster.org/13755
 >Reviewed-on: http://review.gluster.org/13992
 >NetBSD-regression: NetBSD Build System 
 >CentOS-regression: Gluster Build System 
 >Smoke: Gluster Build System 
 >Reviewed-by: Jeff Darcy 

BUG: 1325857
Change-Id: I7c6b2ea065edd7f5dafffeb42fd6c601b4ab8d14
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/14010
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

cluster/afr: Choose local child as source if possible

2016-03-31T06:30:54+00:00

It is better to choose local brick as source if possible to prevent
over the wire read thus saving on bandwidth. Also changed code to not
attempt data-heal if 'source' is selected as arbiter.

 >Change-Id: I9a328d0198422280b13a30ab99545370a301dfea
 >BUG: 1314150
 >Signed-off-by: Pranith Kumar K 
 >Reviewed-on: http://review.gluster.org/13585
 >Smoke: Gluster Build System 
 >NetBSD-regression: NetBSD Build System 
 >Reviewed-by: Krutika Dhananjay 
 >Tested-by: Krutika Dhananjay 
 >CentOS-regression: Gluster Build System 
 >Reviewed-by: Jeff Darcy 
 >(cherry picked from commit 2807e3fc005630213ab7ad251fef13d61c07ac6b)

Change-Id: I24ea66683f81e238a6c1850664a49fe554011a0a
BUG: 1322521
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/13860
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Ravishankar N

afr : Enable auto heal when replica count increases

2016-03-23T11:49:36+00:00

            Backport of: http://review.gluster.org/12454

    This patch is part two change to prevent data loss
    in a replicate volume on doing a add-brick operation.

    Problem: After doing add-brick, there is a chance that
    self heal might happen from the newly added brick rather
    than the source brick, leading to data loss.

    Solution: Mark pending changelogs on afr children for
    the new afr-child so that heal is performed in the
    correct direction.

            >Change-Id: I11871e55eef3593aec874f92214a2d97da229b17
            >BUG: 1276203
            >Signed-off-by: Anuradha Talur 
            >Reviewed-on: http://review.gluster.org/12454
            >Smoke: Gluster Build System 
            >Reviewed-by: Pranith Kumar Karampuri 
            >Tested-by: Pranith Kumar Karampuri 
            >CentOS-regression: Gluster Build System 
            >NetBSD-regression: NetBSD Build System 

Change-Id: Iae6af44f97e612cb3ee8c642254ec3d15ac063f5
BUG: 1320020
Signed-off-by: Anuradha Talur 
Reviewed-on: http://review.gluster.org/13807
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Raghavendra G

afr: Add throttled background client-side heals

2016-03-23T02:21:35+00:00

Backport of: http://review.gluster.org/13207

If a heal is needed after inode refresh (lookup, read_txn), launch it in
the background instead of blocking the fop (that triggered refresh)
until the heal happens.

afr_replies_interpret() is modified such that the heal is
launched only if atleast one sink brick is up.

Max. no of heals that can happen in parallel is configurable via the
'background-self-heal-count' volume option. Any number greater than that
is put in a wait queue whose length is configurable via
'heal-wait-queue-leng' volume option. If the wait queue is also full,
further heals will be ignored.

Default values:  background-self-heal-count=8, heal-wait-queue-leng=128

Change-Id: I9a134b2c29d66b70b7b1278811bd504963aabacc
BUG: 1313312
Signed-off-by: Ravishankar N 
Reviewed-on: http://review.gluster.org/13564
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri