glusterfs.git/xlators/cluster/afr/src/afr-lk-common.c, branch release-3.6

cluster/afr: move messages to new logging framework

2014-05-17T08:46:17+00:00

Change important (from a diagnostics point of view) log messages to use
the gf_msg() framework.

Change-Id: I0a58184bbb78989db149e67f07c140a21c781bc2
BUG: 1075611
Signed-off-by: Ravishankar N 
Reviewed-on: http://review.gluster.org/7784
Reviewed-by: Krutika Dhananjay 
Tested-by: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Pranith Kumar Karampuri

cluster/afr: refactor

2014-03-22T12:25:57+00:00

- Remove client side self-healing completely (opendir, openfd, lookup)
- Re-work readdir-failover to work reliably in case of NFS
- Remove unused/dead lock recovery code
- Consistently use xdata in both calls and callbacks in all FOPs
- Per-inode event generation, used to force inode ctx refresh
- Implement dirty flag support (in place of pending counts)
- Eliminate inode ctx structure, use read subvol bits + event_generation
- Implement inode ctx refreshing based on event generation
- Provide backward compatibility in transactions
- remove unused variables and functions
- make code more consistent in style and pattern
- regularize and clean up inode-write transaction code
- regularize and clean up dir-write transaction code
- regularize and clean up common FOPs
- reorganize transaction framework code
- skip setting xattrs in pending dict if nothing is pending
- re-write self-healing code using syncops
- re-write simpler self-heal-daemon

Change-Id: I1e4080c9796c8a2815c2dab4be3073f389d614a8
BUG: 1021686
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/6010
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

Logging : Improved the log message on unlock failure in afr_unlock_inodelk_cbk.

2013-09-30T19:54:17+00:00

"unlock failed on 1 unlock" seems meaningless in the log message. Improved it.

Change-Id: If67d3f9d4aa5310d0b6728a6c89fa58a5cc93d12
BUG: 1012947
Signed-off-by: Anuradha 
Reviewed-on: http://review.gluster.org/6012
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Gluster Build System

cluster/afr: Reset attempted count before attempting blocking lock

2013-08-29T19:29:13+00:00

Problem:
internal_lock->lk_attempted_count keeps track of the number of blocking
locks attempted. lk_expected_count keeps track of the number locks expected.
Here are the sequence of steps that happen which lead to the illution that
a full file lock is achieved, even without attempting any lock.

2 mounts are doing dd on same file. Both of them witness a brick going
down and coming back up again. Both of the mounts issue self-heal
1) Both mount-1, mount-2 attempt full file locks in self-heal domain.
lets say mount-1 got the lock, mount-2 attempts blocking lock.

2) mount-1 attempts full file lock in data domain. It goes into blocking
mode because some other writes are in progress. Eventually it gets the lock.
But this results in lk_attempted_count to be still as 2 and will not be reset.
It completes syncing the data.

3) mount-1 before unlocking final small range lock attempts full file lock in
data domain to figure out the source/sink. This will be put into blocked mode
again because some other writes are in progress. But this time seeing the
stale value of lk_attempted_count being equal to lk_expected_count, blocking_lock
phase thinks it completed locking without acquiring a single lock :-O.

4) mount-1 reads xattrs without any lock but since it does not modify the xattrs,
no harm is done by this phase. It tries to do unlocks and the unlocks will fail
because the locks are never taken in data domain. mount-1 also unlocks
self-heal domain locks.

Our beloved mount-2 now gets the chance to cause horror :-(.

5) mount-2 gets the full range blocking lock in self-heal domain.
Please note that this sets lk_attempted_count to 2.

6) mount-2 attempts full range lock in data domain, since there are still
writes on going, it switches to blocking mode. But since lk_attempted_count is 2
which is same as lk_expected_count, blocking phase locks thinks it actually got
the full range locks even though not a single lock request went out the wire.

7) mount-2 reads the change-log xattrs, which would give the number of operations
in progress (lets call this 'X'). It does the syncing and at the end of the sync
decrements the changelog by 'X'. But since that 'X' was introduced by 'X' number
of transactions that are in progress, they also decrement the changelog by 'X'.
Effectively for 'X' operations 'X' number of pre-ops are done but 2 times 'X'
number of post-ops are done resulting in -ve changelog numbers.

Fix:
Reset the lk_attempted_count and inode locks array that is used to remember locks
that are granted.

Change-Id: Ic0a79cd16f32392ea7c790511343c73592bbe6bd
BUG: 1002698
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/5736
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

cluster/afr: unlock before aborting transaction

2013-08-29T10:35:44+00:00

Else this results in a missing frame causing a hang

Change-Id: Ib5f3dc6a3999449faa2853cee2944af2fb065a20
BUG: 1002399
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/5731
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

cluster/afr: Refactor inodelk to handle multiple domains

2013-07-04T04:28:11+00:00

- afr_local_copy should not be memduping locked nodes, that would
  mean that lock is taken in self-heal on those nodes even before
  it actually takes the lock. So removed memdup code. Even entry
  lock related copying (lockee info) is also not necessary for
  self-heal functionality, so removing that as well. Since it is
  not local_copy anymore changed its name.

- My editor changed tabs to spaces.

Change-Id: I8dfb92cb8338e9a967c06907a8e29a8404782d61
BUG: 967717
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/5099
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

cluster/afr: Avoid order mismatch in blocking entrylks

2013-06-05T12:22:52+00:00

Problem:
When taking blocking entrylks, afr orders the entrylks based on
uuid_compare of gfids of parent dirs, if they are equal then it orders
them based on the basenames. While this approach works fine, the
implementation assumes loc->gfids to be populated at the time of
the comparison, but loc may have gfid in loc->inode->gfid instead
of loc->gfid which was leading to order mismatches and dead-locks.

Fix:
Implemented loc_gfid which gives gfid by checking both loc->gfid,
loc->inode->gfid. Used this for ordering the blocking entrylks.

Change-Id: Ib0db36bbaf0df09fa87c3c3bb6a834db74fc2154
BUG: 965987
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/5062
Reviewed-by: Krishnan Parthasarathi 
Reviewed-by: Jeff Darcy 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

cluster/afr: Don't queue transactions during open-fd fix

2013-02-23T05:03:03+00:00

Before Anonymous fds are available, afr had to queue up
transactions if the file is not opened on one of its
subvolumes. This happens until the attempt to open the
file either succeeds or fails. These attempts happen
until the file is successfully opened on the subvolume.
Now client xlator uses anonymous fds to perform the fops
if the fd used for the fop is not 'opened'.
Fops will be successful even when the file is not opened
so there is no need to queue up the transactions anymore in afr.
Open is attempted on the subvolume where it is not
opened independent of the fop.

Change-Id: Id1a4b4ebe6f89f9efe8f6a8247918b91247d0819
BUG: 913051
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/4568
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

afr: serialize modification of {entrylk,inodelk}_lock_count

2013-02-07T19:09:35+00:00

Typically this lock was not needed in practice, but with
http://review.gluster.org/3842, this code gets executed in multiple
threads for different servers and we lose a count. This results in
leaked lock and a hang for a future transaction.

Change-Id: I377ed20e44f2a45cff522289dfef181f0653eca2
BUG: 765564
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/4480
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Gluster Build System

cluster/afr: Avoid priv->eager_lock value update race

2013-02-06T17:25:42+00:00

Change-Id: I7049c0c64e36a9dfa4cc0e0b34de7ec111d2f6c1
BUG: 908302
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/4076
Tested-by: Gluster Build System 
Reviewed-by: Jeff Darcy 
Reviewed-by: Anand Avati