glusterfs.git/xlators/cluster/afr/src/afr-dir-write.c, branch v5.4

cluster/thin-arbiter: Consider thin-arbiter before marking new entry changelog

2019-02-18T14:39:55+00:00

If a fop to create an entry fails on one of the data brick,
we mark the pending changelog on the entry on brick for which
it was successful. This is done as part of post op phase to
make sure that entry gets healed even if it gets renamed to
some other path where its parent was not marked as bad.

As it happens as part of post op, we should consider thin-arbiter
to check if the brick, which was successful, is the good brick or not.
This will avoide split brain and other issues.

>Change-Id: I12686675be98f02f70a5186b3ed748c541514d53
>Signed-off-by: Ashish Pandey 

Change-Id: I12686675be98f02f70a5186b3ed748c541514d53
updates: bz#1672314
Signed-off-by: Ashish Pandey

Land part 2 of clang-format changes

2018-09-12T12:22:45+00:00

Change-Id: Ia84cc24c8924e6d22d02ac15f611c10e26db99b4
Signed-off-by: Nigel Babu

cluster/afr: Remove unused code paths

2018-03-06T08:49:31+00:00

Removed
1) afr-v1 self-heal locks related code which is not used anymore
2) transaction has some data types that are not needed, so removed them
3) Never used lock tracing available in afr as gluster's network tracing does
the job. So removed that as well.
4) Changelog is always enabled and afr is always used with locks, so
__changelog_enabled, afr_lock_server_count etc functions can be deleted.
5) transaction.fop/done/resume always call the same functions, so no need
to have these variables.

BUG: 1549606
Change-Id: I370c146fec2892d40e674d232a5d7256e003c7f1
Signed-off-by: Pranith Kumar K

cluster/afr: Fixing the flaws in arbiter becoming source patch

2018-01-13T02:55:44+00:00

Problem:
Setting the write_subvol value to read_subvol in case of metadata
transaction during pre-op (commit 19f9bcff4aada589d4321356c2670ed283f02c03)
might lead to the original problem of arbiter becoming source.

Scenario:
1) All bricks are up and good
2) 2 writes w1 and w2 are in progress in parallel
3) ctx->read_subvol is good for all the subvolumes
4) w1 succeeds on brick0 and fails on brick1, yet to do post-op on
   the disk
5) read/lookup comes on the same file and refreshes read_subvols back
   to all good
6) metadata transaction happens which makes ctx->write_subvol to be
   assigned with ctx->read_subvol which is all good
7) w2 succeeds on brick1 and fails on brick0 and this will update the
   brick in reverse order leading to arbiter becoming source

Fix:
Instead of setting the ctx->write_subvol to ctx->read_subvol in the
pre-op statge, if there is a metadata transaction, check in the
function __afr_set_in_flight_sb_status() if it is a data/metadata
transaction. Use the value of ctx->write_subvol if it is a data
transactions and ctx->read_subvol value for other transactions.

With this patch we assign the value of ctx->write_subvol in the
afr_transaction_perform_fop() with the on disk value, instead of
assigning it in the afr_changelog_pre_op() with the in memory value.

Change-Id: Id2025a7e965f0578af35b1abaac793b019c43cc4
BUG: 1482064
Signed-off-by: karthik-us

Coverity Issue: PW.INCLUDE_RECURSION in several files

2017-11-09T13:21:11+00:00

Coverity ID: 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417,
418, 419, 423, 424, 425, 426, 427, 428, 429, 436, 437, 438, 439,
440, 441, 442, 443

Issue: Event include_recursion

Removed redundant, recursive includes from the files.

Change-Id: I920776b1fa089a2d4917ca722d0075a9239911a7
BUG: 789278
Signed-off-by: Girjesh Rajoria

afr: propagate correct errno for fop failures in arbiter

2017-05-15T12:18:32+00:00

Problem:
If quorum is not met in fop cbk, arbiter sends an ENOTCONN error to the
upper xlators. In a VM workload with sharding enabled, this was leading
to the VM pausing when replace-brick was performed as described in the BZ.

Fix:
Move the fop cbk arbitration logic to afr_handle_quorum() because in
normal replica volumes, that is the function that has the quorum and
errno checks in the fop cbk path before doing a post-op.

Thanks to Pranith for suggesting this approach.

Change-Id: Ie6315db30c5e36326b71b90a01da824109e86796
BUG: 1449610
Signed-off-by: Ravishankar N 
Reviewed-on: https://review.gluster.org/17235
Smoke: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

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

2016-08-22T09:38:36+00:00

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: I9ca634b026ac830b172bac076437cc3bf1ae7d8a
BUG: 1363721
Signed-off-by: Krutika Dhananjay 
Reviewed-on: http://review.gluster.org/15080
Tested-by: Pranith Kumar Karampuri 
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Ravishankar N 
Reviewed-by: Oleksandr Natalenko 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Pranith Kumar Karampuri

cluster/afr: Unwind xdata_rsp even in case of failures

2016-05-31T04:27:35+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

cluster/afr: Don't let NFS cache stat after writes

2016-05-05T01:42:14+00:00

Problem:
Afr does post-ops after write but the stat buffer it unwinds is at the
time of write, so if nfs client caches this, it will see different
ctime when it does stat on it after post-op is done. From NFS client's
perspective it thinks the file is changed. Tar which depends on this
to be correct keeps giving 'file changed as we read it' warning.
If Afr instead has to choose to unwind after post-op, eager-lock,
delayed-post-op will have to be disabled which will lead to bad
performance for all write usecases.

Fix:
Don't let client cache stat after write.

Change-Id: Ic6062acc6e5cdd97a9c83c56bd529ec83cee8a23
BUG: 1302948
Signed-off-by: Pranith Kumar K 
Signed-off-by: Anuradha Talur 
Reviewed-on: http://review.gluster.org/13785
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Niels de Vos