2 domain locking + xattrop for write-txn failures:
--------------------------------------------------
- A post-op wound on TA takes AFR_TA_DOM_NOTIFY range lock and
AFR_TA_DOM_MODIFY full lock, does xattrop on TA and releases
AFR_TA_DOM_MODIFY lock and stores in-memory which brick is bad.

- All further write txn failures are handled based on this in-memory
value without querying the TA.

- When shd heals the files, it does so by requesting full lock on
AFR_TA_DOM_NOTIFY domain. Client uses this as a cue (via upcall),
releases AFR_TA_DOM_NOTIFY range lock and invalidates its in-memory
notion of which brick is bad. The next write txn failure is wound on TA
to again update the in-memory state.

- Any incomplete write txns before the AFR_TA_DOM_NOTIFY upcall release
request is got is completed before the lock is released.

- Any write txns got after the release request are maintained in a ta_waitq.

- After the release is complete, the ta_waitq elements are spliced to a
separate queue which is then processed one by one.

- For fops that come in parallel when the in-memory bad brick is still
unknown, only one is wound to TA on wire. The other ones are maintained
in a ta_onwireq which is then processed after we get the response from
TA.

Change-Id: I32c7b61a61776663601ab0040e2f0767eca1fd64
updates: bz#1648205
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Signed-off-by: Ashish Pandey <aspandey@redhat.com>

With this change when SHD starts the index crawl it requests
all the clients to release the AFR_TA_DOM_NOTIFY lock so that
clients will know the in memory state is no more valid and
any new operations needs to query the thin-arbiter if required.

When SHD completes healing all the files without any failure, it
will again take the AFR_TA_DOM_NOTIFY lock and gets the xattrs on
TA to see whether there are any new failures happened by that time.
If there are new failures marked on TA, SHD will start the crawl
immediately to heal those failures as well. If there are no new
failures, then SHD will take the AFR_TA_DOM_MODIFY lock and unsets
the xattrs on TA, so that both the data bricks will be considered
as good there after.

>Change-Id: I037b89a0823648f314580ba0716d877bd5ddb1f1
>fixes: bz#1579788
>Signed-off-by: karthik-us <ksubrahm@redhat.com>
(cherry picked from commit 5784a00f997212d34bd52b2303e20c097240d91c)

Change-Id: I037b89a0823648f314580ba0716d877bd5ddb1f1
fixes: bz#1648205

Currently, there are possibilities in few places, where a user-controlled
(like filename, program parameter etc) string can be passed as 'fmt' for
printf(), which can lead to segfault, if the user's string contains '%s',
'%d' in it.

While fixing it, makes sense to make the explicit check for such issues
across the codebase, by making the format call properly.

Fixes: CVE-2018-14661

Fixes: bz#1647666
Change-Id: Ib547293f2d9eb618594cbff0df3b9c800e88bde4
Signed-off-by: Amar Tumballi <amarts@redhat.com>

Problem:
Currently for replica volume, even if only one brick is UP
SHD will keep crawling index entries even if it can not
heal anything.

In thin-arbiter volume which is also a replica 2 volume,
this causes inode lock contention which in turn sends
upcall to all the clients to release notify locks, even
if it can not do anything for healing.

This will slow down the client performance and kills the
purpose of keeping in memory information about bad brick.

Solution: Before starting heal or even crawling, check if
sufficient number of children are UP and available to check
and heal entries.

(cherry picked from commit f73b4476b15f9d6d3dc3c8e20c9742aacd857f9f)

Change-Id: I011c9da3b37cae275f791affd56b8f1c1ac9255d
updates: bz#1644645
Signed-off-by: Ashish Pandey <aspandey@redhat.com>

For lease operation, we allocate and store child nodes
data in lease structure. Use the same in afr_lease_cbk()
while checking for the quorum.

Change-Id: If1fdd5a0798888afd39ad3df57d96487baf9d1e6
updates: #350
Signed-off-by: Soumya Koduri <skoduri@redhat.com>

Backport of https://review.gluster.org/#/c/glusterfs/+/21135/

Problem:
When a directory has dirty xattrs due to failed post-ops or when
replace/reset brick is performed, AFR does a conservative merge as
expected, but heal-info reports it as split-brain because there are no
clear sources.

Fix:
Modify pending flag to contain information about pending heals and
split-brains. For directories, if spit-brain flag is not set,just show
them as needing heal and not being in split-brain.

Change-Id: I09ef821f6887c87d315ae99e6b1de05103cd9383
fixes: bz#1638163
Signed-off-by: Ravishankar N <ravishankar@redhat.com>

Change-Id: Ia84cc24c8924e6d22d02ac15f611c10e26db99b4
Signed-off-by: Nigel Babu <nigelb@redhat.com>

xlators/cluster/afr/src/afr-common.c
xlators/cluster/dht/src/dht-common.c
xlators/cluster/dht/src/dht-rebalance.c
xlators/cluster/stripe/src/stripe-helpers.c

strncpy may not be very efficient for short strings copied into
a large buffer: If the length of src is less than n,
strncpy() writes additional null bytes to dest to ensure
that a total of n bytes are written.

Instead, use snprintf().
Also:
- save the result of strlen() and re-use it when possible.
- move from strlen to SLEN (sizeof() ) for const strings.

Compile-tested only!

Change-Id: Icdf79dd3d9f9ff120e4720ff2b8bd016df575c38
updates: bz#1193929
Signed-off-by: Yaniv Kaul <ykaul@redhat.com>

If both data bricks are up, read subvol will be based on read_subvols.

If only one data brick is up:
- First qeury the data-brick that is up. If it blames the other brick,
allow the reads.

- If if doesn't, query the TA to obtain the source of truth.

TODO: See if in-memory state can be maintained for read txns (BZ 1624358).

updates: bz#1579788
Change-Id: I61eec35592af3a1aaf9f90846d9a358b2e4b2fcc
Signed-off-by: Ravishankar N <ravishankar@redhat.com>

This patch fixes buffer size issue 1138522.

Change-Id: Ia12fc8f34f75704f8ed3efae2022c4fd67a8c76c
updates: bz#789278
Signed-off-by: Sanju Rakonde <srakonde@redhat.com>