<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs/jbd2, branch v4.3</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>jbd2: limit number of reserved credits</title>
<updated>2015-08-04T15:21:52+00:00</updated>
<author>
<name>Lukas Czerner</name>
<email>lczerner@redhat.com</email>
</author>
<published>2015-08-04T15:21:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6d3ec14d703c660c4baf8d726538b5415e23b4fb'/>
<id>6d3ec14d703c660c4baf8d726538b5415e23b4fb</id>
<content type='text'>
Currently there is no limitation on number of reserved credits we can
ask for. If we ask for more reserved credits than 1/2 of maximum
transaction size, or if total number of credits exceeds the maximum
transaction size per operation (which is currently only possible with
the former) we will spin forever in start_this_handle().

Fix this by adding this limitation at the start of start_this_handle().

This patch also removes the credit limitation 1/2 of maximum transaction
size, since we really only want to limit the number of reserved credits.
There is not much point to limit the credits if there is still space in
the journal.

This accidentally also fixes the online resize, where due to the
limitation of the journal credits we're unable to grow file systems with
1k block size and size between 16M and 32M. It has been partially fixed
by 2c869b262a10ca99cb866d04087d75311587a30c, but not entirely.

Thanks Jan Kara for helping me getting the correct fix.

Signed-off-by: Lukas Czerner &lt;lczerner@redhat.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently there is no limitation on number of reserved credits we can
ask for. If we ask for more reserved credits than 1/2 of maximum
transaction size, or if total number of credits exceeds the maximum
transaction size per operation (which is currently only possible with
the former) we will spin forever in start_this_handle().

Fix this by adding this limitation at the start of start_this_handle().

This patch also removes the credit limitation 1/2 of maximum transaction
size, since we really only want to limit the number of reserved credits.
There is not much point to limit the credits if there is still space in
the journal.

This accidentally also fixes the online resize, where due to the
limitation of the journal credits we're unable to grow file systems with
1k block size and size between 16M and 32M. It has been partially fixed
by 2c869b262a10ca99cb866d04087d75311587a30c, but not entirely.

Thanks Jan Kara for helping me getting the correct fix.

Signed-off-by: Lukas Czerner &lt;lczerner@redhat.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>jbd2: avoid infinite loop when destroying aborted journal</title>
<updated>2015-07-28T18:57:14+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.com</email>
</author>
<published>2015-07-28T18:57:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=841df7df196237ea63233f0f9eaa41db53afd70f'/>
<id>841df7df196237ea63233f0f9eaa41db53afd70f</id>
<content type='text'>
Commit 6f6a6fda2945 "jbd2: fix ocfs2 corrupt when updating journal
superblock fails" changed jbd2_cleanup_journal_tail() to return EIO
when the journal is aborted. That makes logic in
jbd2_log_do_checkpoint() bail out which is fine, except that
jbd2_journal_destroy() expects jbd2_log_do_checkpoint() to always make
a progress in cleaning the journal. Without it jbd2_journal_destroy()
just loops in an infinite loop.

Fix jbd2_journal_destroy() to cleanup journal checkpoint lists of
jbd2_log_do_checkpoint() fails with error.

Reported-by: Eryu Guan &lt;guaneryu@gmail.com&gt;
Tested-by: Eryu Guan &lt;guaneryu@gmail.com&gt;
Fixes: 6f6a6fda294506dfe0e3e0a253bb2d2923f28f0a
Signed-off-by: Jan Kara &lt;jack@suse.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 6f6a6fda2945 "jbd2: fix ocfs2 corrupt when updating journal
superblock fails" changed jbd2_cleanup_journal_tail() to return EIO
when the journal is aborted. That makes logic in
jbd2_log_do_checkpoint() bail out which is fine, except that
jbd2_journal_destroy() expects jbd2_log_do_checkpoint() to always make
a progress in cleaning the journal. Without it jbd2_journal_destroy()
just loops in an infinite loop.

Fix jbd2_journal_destroy() to cleanup journal checkpoint lists of
jbd2_log_do_checkpoint() fails with error.

Reported-by: Eryu Guan &lt;guaneryu@gmail.com&gt;
Tested-by: Eryu Guan &lt;guaneryu@gmail.com&gt;
Fixes: 6f6a6fda294506dfe0e3e0a253bb2d2923f28f0a
Signed-off-by: Jan Kara &lt;jack@suse.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext4, jbd2: add REQ_FUA flag when recording an error in the superblock</title>
<updated>2015-07-23T13:46:11+00:00</updated>
<author>
<name>Daeho Jeong</name>
<email>daeho.jeong@samsung.com</email>
</author>
<published>2015-07-23T13:46:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=564bc402526e437729ecafe3c3511f7cab9f0327'/>
<id>564bc402526e437729ecafe3c3511f7cab9f0327</id>
<content type='text'>
When an error condition is detected, an error status should be recorded into
superblocks of EXT4 or JBD2. However, the write request is submitted now
without REQ_FUA flag, even in "barrier=1" mode, which is followed by
panic() function in "errors=panic" mode. On mobile devices which make
whole system reset as soon as kernel panic occurs, this write request
containing an error flag will disappear just from storage cache without
written to the physical cells. Therefore, when next start, even forever,
the error flag cannot be shown in both superblocks, and e2fsck cannot fix
the filesystem problems automatically, unless e2fsck is executed in
force checking mode.

[ Changed use test_opt(sb, BARRIER) of checking the journal flags -- TYT ]

Signed-off-by: Daeho Jeong &lt;daeho.jeong@samsung.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When an error condition is detected, an error status should be recorded into
superblocks of EXT4 or JBD2. However, the write request is submitted now
without REQ_FUA flag, even in "barrier=1" mode, which is followed by
panic() function in "errors=panic" mode. On mobile devices which make
whole system reset as soon as kernel panic occurs, this write request
containing an error flag will disappear just from storage cache without
written to the physical cells. Therefore, when next start, even forever,
the error flag cannot be shown in both superblocks, and e2fsck cannot fix
the filesystem problems automatically, unless e2fsck is executed in
force checking mode.

[ Changed use test_opt(sb, BARRIER) of checking the journal flags -- TYT ]

Signed-off-by: Daeho Jeong &lt;daeho.jeong@samsung.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>jbd2: speedup jbd2_journal_dirty_metadata()</title>
<updated>2015-07-12T22:11:30+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2015-07-12T22:11:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6e06ae88edae77379bef7c0cb7d3c2dd88676867'/>
<id>6e06ae88edae77379bef7c0cb7d3c2dd88676867</id>
<content type='text'>
It is often the case that we mark buffer as having dirty metadata when
the buffer is already in that state (frequent for bitmaps, inode table
blocks, superblock). Thus it is unnecessary to contend on grabbing
journal head reference and bh_state lock. Avoid that by checking whether
any modification to the buffer is needed before grabbing any locks or
references.

[ Note: this is a fixed version of commit 2143c1965a761, which was
  reverted in ebeaa8ddb3663b5 due to a false positive triggering of an
  assertion check. -- Ted ]

Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It is often the case that we mark buffer as having dirty metadata when
the buffer is already in that state (frequent for bitmaps, inode table
blocks, superblock). Thus it is unnecessary to contend on grabbing
journal head reference and bh_state lock. Avoid that by checking whether
any modification to the buffer is needed before grabbing any locks or
references.

[ Note: this is a fixed version of commit 2143c1965a761, which was
  reverted in ebeaa8ddb3663b5 due to a false positive triggering of an
  assertion check. -- Ted ]

Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "jbd2: speedup jbd2_journal_dirty_metadata()"</title>
<updated>2015-06-27T16:41:50+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-06-27T16:41:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ebeaa8ddb3663b5c6cfc205605c35116381550c5'/>
<id>ebeaa8ddb3663b5c6cfc205605c35116381550c5</id>
<content type='text'>
This reverts commit 2143c1965a761332ae417b22fd477b636e4f54ec.

This commit seems to be the cause of the following jbd2 assertion
failure:

   ------------[ cut here ]------------
   kernel BUG at fs/jbd2/transaction.c:1325!
   invalid opcode: 0000 [#1] SMP
   Modules linked in: bnep bluetooth fuse ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 ...
   CPU: 7 PID: 5509 Comm: gcc Not tainted 4.1.0-10944-g2a298679b411 #1
   Hardware name:                  /DH87RL, BIOS RLH8710H.86A.0327.2014.0924.1645 09/24/2014
   task: ffff8803bf866040 ti: ffff880308528000 task.ti: ffff880308528000
   RIP: jbd2_journal_dirty_metadata+0x237/0x290
   Call Trace:
     __ext4_handle_dirty_metadata+0x43/0x1f0
     ext4_handle_dirty_dirent_node+0xde/0x160
     ? jbd2_journal_get_write_access+0x36/0x50
     ext4_delete_entry+0x112/0x160
     ? __ext4_journal_start_sb+0x52/0xb0
     ext4_unlink+0xfa/0x260
     vfs_unlink+0xec/0x190
     do_unlinkat+0x24a/0x270
     SyS_unlink+0x11/0x20
     entry_SYSCALL_64_fastpath+0x12/0x6a
   ---[ end trace ae033ebde8d080b4 ]---

which is not easily reproducible (I've seen it just once, and then Ted
was able to reproduce it once).  Revert it while Ted and Jan try to
figure out what is wrong.

Cc: Jan Kara &lt;jack@suse.cz&gt;
Acked-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 2143c1965a761332ae417b22fd477b636e4f54ec.

This commit seems to be the cause of the following jbd2 assertion
failure:

   ------------[ cut here ]------------
   kernel BUG at fs/jbd2/transaction.c:1325!
   invalid opcode: 0000 [#1] SMP
   Modules linked in: bnep bluetooth fuse ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 ...
   CPU: 7 PID: 5509 Comm: gcc Not tainted 4.1.0-10944-g2a298679b411 #1
   Hardware name:                  /DH87RL, BIOS RLH8710H.86A.0327.2014.0924.1645 09/24/2014
   task: ffff8803bf866040 ti: ffff880308528000 task.ti: ffff880308528000
   RIP: jbd2_journal_dirty_metadata+0x237/0x290
   Call Trace:
     __ext4_handle_dirty_metadata+0x43/0x1f0
     ext4_handle_dirty_dirent_node+0xde/0x160
     ? jbd2_journal_get_write_access+0x36/0x50
     ext4_delete_entry+0x112/0x160
     ? __ext4_journal_start_sb+0x52/0xb0
     ext4_unlink+0xfa/0x260
     vfs_unlink+0xec/0x190
     do_unlinkat+0x24a/0x270
     SyS_unlink+0x11/0x20
     entry_SYSCALL_64_fastpath+0x12/0x6a
   ---[ end trace ae033ebde8d080b4 ]---

which is not easily reproducible (I've seen it just once, and then Ted
was able to reproduce it once).  Revert it while Ted and Jan try to
figure out what is wrong.

Cc: Jan Kara &lt;jack@suse.cz&gt;
Acked-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2015-06-26T16:52:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-06-26T16:52:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=47a469421d792dcb91a1e73319d26134241953d2'/>
<id>47a469421d792dcb91a1e73319d26134241953d2</id>
<content type='text'>
Merge second patchbomb from Andrew Morton:

 - most of the rest of MM

 - lots of misc things

 - procfs updates

 - printk feature work

 - updates to get_maintainer, MAINTAINERS, checkpatch

 - lib/ updates

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (96 commits)
  exit,stats: /* obey this comment */
  coredump: add __printf attribute to cn_*printf functions
  coredump: use from_kuid/kgid when formatting corename
  fs/reiserfs: remove unneeded cast
  NILFS2: support NFSv2 export
  fs/befs/btree.c: remove unneeded initializations
  fs/minix: remove unneeded cast
  init/do_mounts.c: add create_dev() failure log
  kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
  fs/efs: femove unneeded cast
  checkpatch: emit "NOTE: &lt;types&gt;" message only once after multiple files
  checkpatch: emit an error when there's a diff in a changelog
  checkpatch: validate MODULE_LICENSE content
  checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY
  checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr()
  checkpatch: fix processing of MEMSET issues
  checkpatch: suggest using ether_addr_equal*()
  checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files
  checkpatch: remove local from codespell path
  checkpatch: add --showfile to allow input via pipe to show filenames
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Merge second patchbomb from Andrew Morton:

 - most of the rest of MM

 - lots of misc things

 - procfs updates

 - printk feature work

 - updates to get_maintainer, MAINTAINERS, checkpatch

 - lib/ updates

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (96 commits)
  exit,stats: /* obey this comment */
  coredump: add __printf attribute to cn_*printf functions
  coredump: use from_kuid/kgid when formatting corename
  fs/reiserfs: remove unneeded cast
  NILFS2: support NFSv2 export
  fs/befs/btree.c: remove unneeded initializations
  fs/minix: remove unneeded cast
  init/do_mounts.c: add create_dev() failure log
  kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
  fs/efs: femove unneeded cast
  checkpatch: emit "NOTE: &lt;types&gt;" message only once after multiple files
  checkpatch: emit an error when there's a diff in a changelog
  checkpatch: validate MODULE_LICENSE content
  checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY
  checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr()
  checkpatch: fix processing of MEMSET issues
  checkpatch: suggest using ether_addr_equal*()
  checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files
  checkpatch: remove local from codespell path
  checkpatch: add --showfile to allow input via pipe to show filenames
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>fs/jbd2/journal.c: use strreplace()</title>
<updated>2015-06-26T00:00:40+00:00</updated>
<author>
<name>Rasmus Villemoes</name>
<email>linux@rasmusvillemoes.dk</email>
</author>
<published>2015-06-25T22:02:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=81ae394bdc473cafa5074948516fc83b504ea60b'/>
<id>81ae394bdc473cafa5074948516fc83b504ea60b</id>
<content type='text'>
In one case, we eliminate a local variable; in the other a strlen()
call and some .text.

Signed-off-by: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In one case, we eliminate a local variable; in the other a strlen()
call and some .text.

Signed-off-by: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>jbd2: speedup jbd2_journal_dirty_metadata()</title>
<updated>2015-06-21T01:44:17+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2015-06-21T01:44:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2143c1965a761332ae417b22fd477b636e4f54ec'/>
<id>2143c1965a761332ae417b22fd477b636e4f54ec</id>
<content type='text'>
It is often the case that we mark buffer as having dirty metadata when
the buffer is already in that state (frequent for bitmaps, inode table
blocks, superblock). Thus it is unnecessary to contend on grabbing
journal head reference and bh_state lock. Avoid that by checking whether
any modification to the buffer is needed before grabbing any locks or
references.

Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It is often the case that we mark buffer as having dirty metadata when
the buffer is already in that state (frequent for bitmaps, inode table
blocks, superblock). Thus it is unnecessary to contend on grabbing
journal head reference and bh_state lock. Avoid that by checking whether
any modification to the buffer is needed before grabbing any locks or
references.

Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>jbd2: get rid of open coded allocation retry loop</title>
<updated>2015-06-15T19:45:58+00:00</updated>
<author>
<name>Michal Hocko</name>
<email>mhocko@suse.cz</email>
</author>
<published>2015-06-15T19:45:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7b506b1035326543b7cd2d768449ccbd1ef3f368'/>
<id>7b506b1035326543b7cd2d768449ccbd1ef3f368</id>
<content type='text'>
insert_revoke_hash does an open coded endless allocation loop if
journal_oom_retry is true. It doesn't implement any allocation fallback
strategy between the retries, though. The memory allocator doesn't know
about the never fail requirement so it cannot potentially help to move
on with the allocation (e.g. use memory reserves).

Get rid of the retry loop and use __GFP_NOFAIL instead. We will lose the
debugging message but I am not sure it is anyhow helpful.

Do the same for journal_alloc_journal_head which is doing a similar
thing.

Signed-off-by: Michal Hocko &lt;mhocko@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
insert_revoke_hash does an open coded endless allocation loop if
journal_oom_retry is true. It doesn't implement any allocation fallback
strategy between the retries, though. The memory allocator doesn't know
about the never fail requirement so it cannot potentially help to move
on with the allocation (e.g. use memory reserves).

Get rid of the retry loop and use __GFP_NOFAIL instead. We will lose the
debugging message but I am not sure it is anyhow helpful.

Do the same for journal_alloc_journal_head which is doing a similar
thing.

Signed-off-by: Michal Hocko &lt;mhocko@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>jbd2: fix ocfs2 corrupt when updating journal superblock fails</title>
<updated>2015-06-15T18:36:01+00:00</updated>
<author>
<name>Joseph Qi</name>
<email>joseph.qi@huawei.com</email>
</author>
<published>2015-06-15T18:36:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6f6a6fda294506dfe0e3e0a253bb2d2923f28f0a'/>
<id>6f6a6fda294506dfe0e3e0a253bb2d2923f28f0a</id>
<content type='text'>
If updating journal superblock fails after journal data has been
flushed, the error is omitted and this will mislead the caller as a
normal case.  In ocfs2, the checkpoint will be treated successfully
and the other node can get the lock to update. Since the sb_start is
still pointing to the old log block, it will rewrite the journal data
during journal recovery by the other node. Thus the new updates will
be overwritten and ocfs2 corrupts.  So in above case we have to return
the error, and ocfs2_commit_cache will take care of the error and
prevent the other node to do update first.  And only after recovering
journal it can do the new updates.

The issue discussion mail can be found at:
https://oss.oracle.com/pipermail/ocfs2-devel/2015-June/010856.html
http://comments.gmane.org/gmane.comp.file-systems.ext4/48841

[ Fixed bug in patch which allowed a non-negative error return from
  jbd2_cleanup_journal_tail() to leak out of jbd2_fjournal_flush(); this
  was causing xfstests ext4/306 to fail. -- Ted ]

Reported-by: Yiwen Jiang &lt;jiangyiwen@huawei.com&gt;
Signed-off-by: Joseph Qi &lt;joseph.qi@huawei.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Tested-by: Yiwen Jiang &lt;jiangyiwen@huawei.com&gt;
Cc: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Cc: stable@vger.kernel.org
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<pre>
If updating journal superblock fails after journal data has been
flushed, the error is omitted and this will mislead the caller as a
normal case.  In ocfs2, the checkpoint will be treated successfully
and the other node can get the lock to update. Since the sb_start is
still pointing to the old log block, it will rewrite the journal data
during journal recovery by the other node. Thus the new updates will
be overwritten and ocfs2 corrupts.  So in above case we have to return
the error, and ocfs2_commit_cache will take care of the error and
prevent the other node to do update first.  And only after recovering
journal it can do the new updates.

The issue discussion mail can be found at:
https://oss.oracle.com/pipermail/ocfs2-devel/2015-June/010856.html
http://comments.gmane.org/gmane.comp.file-systems.ext4/48841

[ Fixed bug in patch which allowed a non-negative error return from
  jbd2_cleanup_journal_tail() to leak out of jbd2_fjournal_flush(); this
  was causing xfstests ext4/306 to fail. -- Ted ]

Reported-by: Yiwen Jiang &lt;jiangyiwen@huawei.com&gt;
Signed-off-by: Joseph Qi &lt;joseph.qi@huawei.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Tested-by: Yiwen Jiang &lt;jiangyiwen@huawei.com&gt;
Cc: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Cc: stable@vger.kernel.org
</pre>
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