glusterfs.git/libglusterfs/src/glusterfs, branch v8.2

libglusterfs: fix dict leak

2020-09-07T04:52:58+00:00

Problem:
gf_rev_dns_lookup_cached() allocated struct dnscache->dict if it was null
but the freeing was left to the caller.

Fix:
Moved dict allocation and freeing into corresponding init and fini
routines so that its easier for the caller to avoid such leaks.

Updates: #1000
Change-Id: I90d6a6f85ca2dd4fe0ab461177aaa9ac9c1fbcf9
Signed-off-by: Ravishankar N 
(cherry picked from commit 079f7a7d8a2bd85070c1da4dde2452ca82a1cdbb)

posix: Implement a janitor thread to close fd

2020-08-21T10:38:07+00:00

Problem: In the commit fb20713b380e1df8d7f9e9df96563be2f9144fd6 we use
         syntask to close fd but we have found the patch is reducing the
         performance

Solution: Use janitor thread to close fd's and save the pfd ctx into
          ctx janitor list and also save the posix_xlator into pfd object to
          avoid the race condition during cleanup in brick_mux environment

Change-Id: Ifb3d18a854b267333a3a9e39845bfefb83fbc092
Fixes: #1396
Signed-off-by: Mohit Agrawal 
(cherry picked from commit 41b9616435cbdf671805856e487e373060c9455b)

open-behind: rewrite of internal logic

2020-06-29T12:51:52+00:00

There was a critical flaw in the previous implementation of open-behind.

When an open is done in the background, it's necessary to take a
reference on the fd_t object because once we "fake" the open answer,
the fd could be destroyed. However as long as there's a reference,
the release function won't be called. So, if the application closes
the file descriptor without having actually opened it, there will
always remain at least 1 reference, causing a leak.

To avoid this problem, the previous implementation didn't take a
reference on the fd_t, so there were races where the fd could be
destroyed while it was still in use.

To fix this, I've implemented a new xlator cbk that gets called from
fuse when the application closes a file descriptor.

The whole logic of handling background opens have been simplified and
it's more efficient now. Only if the fop needs to be delayed until an
open completes, a stub is created. Otherwise no memory allocations are
needed.

Correctly handling the close request while the open is still pending
has added a bit of complexity, but overall normal operation is simpler.

Change-Id: I6376a5491368e0e1c283cc452849032636261592
Fixes: #1225
Signed-off-by: Xavi Hernandez

syncop: improve scaling and implement more tools

2020-05-30T05:17:12+00:00

The current scaling of the syncop thread pool is not working properly
and can leave some tasks in the run queue more time than necessary
when the maximum number of threads is not reached.

This patch provides a better scaling condition to react faster to
pending work.

Condition variables and sleep in the context of a synctask have also
been implemented. Their purpose is to replace regular condition
variables and sleeps that block synctask threads and prevent other
tasks to be executed.

The new features have been applied to several places in glusterd.

Change-Id: Ic50b7c73c104f9e41f08101a357d30b95efccfbf
Fixes: #1116
Signed-off-by: Xavi Hernandez

Posix: Optimize posix code to improve file creation

2020-04-06T10:43:26+00:00

Problem: Before executing a fop in POSIX xlator it builds an internal
         path based on GFID.To validate the path it call's (l)stat
         system call and while .glusterfs is heavily loaded kernel takes
         time to lookup inode and due to that performance drops

Solution: In this patch we followed two ways to improve the performance.
          1) Keep open fd specific to first level directory(gfid[0])
             in .glusterfs, it would force to kernel keep the inodes
             from all those files in cache. In case of memory pressure
             kernel won't uncache first level inodes. We need to open
             256 fd's per brick to access the entry faster.
          2) Use at based call's to access relative path to reduce
             path based lookup time.

Note: To verify the patch we have executed kernel untar 100 times on 6
      different clients after enabling metadata group-cache and some
      other option.We were getting more than 20 percent improvement in
      kenel untar after applying the patch.

Credits: Xavi Hernandez 
Change-Id: I1643e6b01ed669b2bb148d02f4e6a8e08da45343
updates: #891
Signed-off-by: Mohit Agrawal

Posix: Use simple approach to close fd

2020-03-20T04:08:42+00:00

Problem: posix_release(dir) functions add the fd's into a ctx->janitor_fds
         and janitor thread closes the fd's.In brick_mux environment it is
         difficult to handle race condition in janitor threads because brick
         spawns a single janitor thread for all bricks.

Solution: Use synctask to execute posix_release(dir) functions instead of 
          using background a thread to close fds.

Credits: Pranith Karampuri 
Change-Id: Iffb031f0695a7da83d5a2f6bac8863dad225317e
Fixes: bz#1811631
Signed-off-by: Mohit Agrawal

utime: resolve an issue of permission denied logs

2020-03-13T12:15:21+00:00

In case where uid is not set to be 0, there are possible errors
from acl xlator. So, set `uid = 0;` with pid indicating this is
set from UTIME activity.

The message "E [MSGID: 148002] [utime.c:146:gf_utime_set_mdata_setxattr_cbk] 0-dev_SNIP_data-utime: dict set of key for set-ctime-mdata failed [Permission denied]" repeated 2 times between [2019-12-19 21:27:55.042634] and [2019-12-19 21:27:55.047887]

Change-Id: Ieadf329835a40a13ac0bf908dac776e66954466c
Fixes: #832
Signed-off-by: Amar Tumballi

core: fix memory pool management races

2020-02-18T17:29:51+00:00

Objects allocated from a per-thread memory pool keep a reference to it
to be able to return the object to the pool when not used anymore. The
object holding this reference can have a long life cycle that could
survive a glfs_fini() call.

This means that it's unsafe to destroy memory pools from glfs_fini().

Another side effect of destroying memory pools from glfs_fini() is that
the TLS variable that points to one of those pools cannot be reset for
all alive threads.  This means that any attempt to allocate memory from
those threads will access already free'd memory, which is very
dangerous.

To fix these issues, mem_pools_fini() doesn't destroy pool lists
anymore. Only at process termination the pools are destroyed.

Change-Id: Ib189a5510ab6bdac78983c6c65a022e9634b0965
Fixes: bz#1801684
Signed-off-by: Xavi Hernandez

libglusterfs-xlator: structure logging

2020-02-14T07:16:48+00:00

convert all gf_msg() to gf_smsg()

Change-Id: Id542e05faadb8041b472a2298c71fe62730e65fc
Updates: #657
Signed-off-by: yatipadia

volgen: make thin-arbiter name unique in 'pending-xattr' option

2020-02-12T16:16:46+00:00

Thin-arbiter module makes use of 'pending-xattr' name for the translator
as the filename which gets created in thin-arbiter node. By making this
unique, we can host single thin-arbiter node for multiple clusters.

Updates: #763
Change-Id: Ib3c732e7e04e6dba229e71ae3e64f1f3cb6d794d
Signed-off-by: Amar Tumballi