<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/fs, branch v4.0-rc4</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>locks: fix generic_delete_lease tracepoint to use victim pointer</title>
<updated>2015-03-14T13:45:35+00:00</updated>
<author>
<name>Jeff Layton</name>
<email>jeff.layton@primarydata.com</email>
</author>
<published>2015-03-14T13:45:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a9b1b455c519ee2fd6a4f9c069511e67b5be1ac4'/>
<id>a9b1b455c519ee2fd6a4f9c069511e67b5be1ac4</id>
<content type='text'>
It's possible that "fl" won't point at a valid lock at this point, so
use "victim" instead which is either a valid lock or NULL.

Signed-off-by: Jeff Layton &lt;jeff.layton@primarydata.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It's possible that "fl" won't point at a valid lock at this point, so
use "victim" instead which is either a valid lock or NULL.

Signed-off-by: Jeff Layton &lt;jeff.layton@primarydata.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fanotify: fix event filtering with FAN_ONDIR set</title>
<updated>2015-03-13T01:46:08+00:00</updated>
<author>
<name>Suzuki K. Poulose</name>
<email>suzuki.poulose@arm.com</email>
</author>
<published>2015-03-12T23:26:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b3c1030d50bad39383fcfa6721bd3c35463b3f3f'/>
<id>b3c1030d50bad39383fcfa6721bd3c35463b3f3f</id>
<content type='text'>
With FAN_ONDIR set, the user can end up getting events, which it hasn't
marked.  This was revealed with fanotify04 testcase failure on
Linux-4.0-rc1, and is a regression from 3.19, revealed with 66ba93c0d7fe6
("fanotify: don't set FAN_ONDIR implicitly on a marks ignored mask").

   # /opt/ltp/testcases/bin/fanotify04
   [ ... ]
  fanotify04    7  TPASS  :  event generated properly for type 100000
  fanotify04    8  TFAIL  :  fanotify04.c:147: got unexpected event 30
  fanotify04    9  TPASS  :  No event as expected

The testcase sets the adds the following marks : FAN_OPEN | FAN_ONDIR for
a fanotify on a dir.  Then does an open(), followed by close() of the
directory and expects to see an event FAN_OPEN(0x20).  However, the
fanotify returns (FAN_OPEN|FAN_CLOSE_NOWRITE(0x10)).  This happens due to
the flaw in the check for event_mask in fanotify_should_send_event() which
does:

	if (event_mask &amp; marks_mask &amp; ~marks_ignored_mask)
		return true;

where, event_mask == (FAN_ONDIR | FAN_CLOSE_NOWRITE),
       marks_mask == (FAN_ONDIR | FAN_OPEN),
       marks_ignored_mask == 0

Fix this by masking the outgoing events to the user, as we already take
care of FAN_ONDIR and FAN_EVENT_ON_CHILD.

Signed-off-by: Suzuki K. Poulose &lt;suzuki.poulose@arm.com&gt;
Tested-by: Lino Sanfilippo &lt;LinoSanfilippo@gmx.de&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Cc: Eric Paris &lt;eparis@redhat.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&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>
With FAN_ONDIR set, the user can end up getting events, which it hasn't
marked.  This was revealed with fanotify04 testcase failure on
Linux-4.0-rc1, and is a regression from 3.19, revealed with 66ba93c0d7fe6
("fanotify: don't set FAN_ONDIR implicitly on a marks ignored mask").

   # /opt/ltp/testcases/bin/fanotify04
   [ ... ]
  fanotify04    7  TPASS  :  event generated properly for type 100000
  fanotify04    8  TFAIL  :  fanotify04.c:147: got unexpected event 30
  fanotify04    9  TPASS  :  No event as expected

The testcase sets the adds the following marks : FAN_OPEN | FAN_ONDIR for
a fanotify on a dir.  Then does an open(), followed by close() of the
directory and expects to see an event FAN_OPEN(0x20).  However, the
fanotify returns (FAN_OPEN|FAN_CLOSE_NOWRITE(0x10)).  This happens due to
the flaw in the check for event_mask in fanotify_should_send_event() which
does:

	if (event_mask &amp; marks_mask &amp; ~marks_ignored_mask)
		return true;

where, event_mask == (FAN_ONDIR | FAN_CLOSE_NOWRITE),
       marks_mask == (FAN_ONDIR | FAN_OPEN),
       marks_ignored_mask == 0

Fix this by masking the outgoing events to the user, as we already take
care of FAN_ONDIR and FAN_EVENT_ON_CHILD.

Signed-off-by: Suzuki K. Poulose &lt;suzuki.poulose@arm.com&gt;
Tested-by: Lino Sanfilippo &lt;LinoSanfilippo@gmx.de&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Cc: Eric Paris &lt;eparis@redhat.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&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>nilfs2: fix deadlock of segment constructor during recovery</title>
<updated>2015-03-13T01:46:08+00:00</updated>
<author>
<name>Ryusuke Konishi</name>
<email>konishi.ryusuke@lab.ntt.co.jp</email>
</author>
<published>2015-03-12T23:26:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=283ee1482f349d6c0c09dfb725db5880afc56813'/>
<id>283ee1482f349d6c0c09dfb725db5880afc56813</id>
<content type='text'>
According to a report from Yuxuan Shui, nilfs2 in kernel 3.19 got stuck
during recovery at mount time.  The code path that caused the deadlock was
as follows:

  nilfs_fill_super()
    load_nilfs()
      nilfs_salvage_orphan_logs()
        * Do roll-forwarding, attach segment constructor for recovery,
          and kick it.

        nilfs_segctor_thread()
          nilfs_segctor_thread_construct()
           * A lock is held with nilfs_transaction_lock()
             nilfs_segctor_do_construct()
               nilfs_segctor_drop_written_files()
                 iput()
                   iput_final()
                     write_inode_now()
                       writeback_single_inode()
                         __writeback_single_inode()
                           do_writepages()
                             nilfs_writepage()
                               nilfs_construct_dsync_segment()
                                 nilfs_transaction_lock() --&gt; deadlock

This can happen if commit 7ef3ff2fea8b ("nilfs2: fix deadlock of segment
constructor over I_SYNC flag") is applied and roll-forward recovery was
performed at mount time.  The roll-forward recovery can happen if datasync
write is done and the file system crashes immediately after that.  For
instance, we can reproduce the issue with the following steps:

 &lt; nilfs2 is mounted on /nilfs (device: /dev/sdb1) &gt;
 # dd if=/dev/zero of=/nilfs/test bs=4k count=1 &amp;&amp; sync
 # dd if=/dev/zero of=/nilfs/test conv=notrunc oflag=dsync bs=4k
 count=1 &amp;&amp; reboot -nfh
 &lt; the system will immediately reboot &gt;
 # mount -t nilfs2 /dev/sdb1 /nilfs

The deadlock occurs because iput() can run segment constructor through
writeback_single_inode() if MS_ACTIVE flag is not set on sb-&gt;s_flags.  The
above commit changed segment constructor so that it calls iput()
asynchronously for inodes with i_nlink == 0, but that change was
imperfect.

This fixes the another deadlock by deferring iput() in segment constructor
even for the case that mount is not finished, that is, for the case that
MS_ACTIVE flag is not set.

Signed-off-by: Ryusuke Konishi &lt;konishi.ryusuke@lab.ntt.co.jp&gt;
Reported-by: Yuxuan Shui &lt;yshuiv7@gmail.com&gt;
Tested-by: Ryusuke Konishi &lt;konishi.ryusuke@lab.ntt.co.jp&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: &lt;stable@vger.kernel.org&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>
According to a report from Yuxuan Shui, nilfs2 in kernel 3.19 got stuck
during recovery at mount time.  The code path that caused the deadlock was
as follows:

  nilfs_fill_super()
    load_nilfs()
      nilfs_salvage_orphan_logs()
        * Do roll-forwarding, attach segment constructor for recovery,
          and kick it.

        nilfs_segctor_thread()
          nilfs_segctor_thread_construct()
           * A lock is held with nilfs_transaction_lock()
             nilfs_segctor_do_construct()
               nilfs_segctor_drop_written_files()
                 iput()
                   iput_final()
                     write_inode_now()
                       writeback_single_inode()
                         __writeback_single_inode()
                           do_writepages()
                             nilfs_writepage()
                               nilfs_construct_dsync_segment()
                                 nilfs_transaction_lock() --&gt; deadlock

This can happen if commit 7ef3ff2fea8b ("nilfs2: fix deadlock of segment
constructor over I_SYNC flag") is applied and roll-forward recovery was
performed at mount time.  The roll-forward recovery can happen if datasync
write is done and the file system crashes immediately after that.  For
instance, we can reproduce the issue with the following steps:

 &lt; nilfs2 is mounted on /nilfs (device: /dev/sdb1) &gt;
 # dd if=/dev/zero of=/nilfs/test bs=4k count=1 &amp;&amp; sync
 # dd if=/dev/zero of=/nilfs/test conv=notrunc oflag=dsync bs=4k
 count=1 &amp;&amp; reboot -nfh
 &lt; the system will immediately reboot &gt;
 # mount -t nilfs2 /dev/sdb1 /nilfs

The deadlock occurs because iput() can run segment constructor through
writeback_single_inode() if MS_ACTIVE flag is not set on sb-&gt;s_flags.  The
above commit changed segment constructor so that it calls iput()
asynchronously for inodes with i_nlink == 0, but that change was
imperfect.

This fixes the another deadlock by deferring iput() in segment constructor
even for the case that mount is not finished, that is, for the case that
MS_ACTIVE flag is not set.

Signed-off-by: Ryusuke Konishi &lt;konishi.ryusuke@lab.ntt.co.jp&gt;
Reported-by: Yuxuan Shui &lt;yshuiv7@gmail.com&gt;
Tested-by: Ryusuke Konishi &lt;konishi.ryusuke@lab.ntt.co.jp&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: &lt;stable@vger.kernel.org&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>ocfs2: make append_dio an incompat feature</title>
<updated>2015-03-13T01:46:07+00:00</updated>
<author>
<name>Mark Fasheh</name>
<email>mfasheh@suse.de</email>
</author>
<published>2015-03-12T23:25:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=18d585f0f2d4c9dc7dfe6e69dcae4933d5a428c9'/>
<id>18d585f0f2d4c9dc7dfe6e69dcae4933d5a428c9</id>
<content type='text'>
It turns out that making this feature ro_compat isn't quite enough to
prevent accidental corruption on mount from older kernels.  Ocfs2 (like
other file systems) will process orphaned inodes even when the user mounts
in 'ro' mode.  So for the case of a filesystem not knowing the append_dio
feature, mounting the filesystem could result in orphaned-for-dio files
being deleted, which we clearly don't want.

So instead, turn this into an incompat flag.

Btw, this is kind of my fault - initially I asked that we add a flag to
cover the feature and even suggested that we use an ro flag.  It wasn't
until I was looking through our commits for v4.0-rc1 that I realized we
actually want this to be incompat.

Signed-off-by: Mark Fasheh &lt;mfasheh@suse.de&gt;
Cc: Joseph Qi &lt;joseph.qi@huawei.com&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&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>
It turns out that making this feature ro_compat isn't quite enough to
prevent accidental corruption on mount from older kernels.  Ocfs2 (like
other file systems) will process orphaned inodes even when the user mounts
in 'ro' mode.  So for the case of a filesystem not knowing the append_dio
feature, mounting the filesystem could result in orphaned-for-dio files
being deleted, which we clearly don't want.

So instead, turn this into an incompat flag.

Btw, this is kind of my fault - initially I asked that we add a flag to
cover the feature and even suggested that we use an ro flag.  It wasn't
until I was looking through our commits for v4.0-rc1 that I realized we
actually want this to be incompat.

Signed-off-by: Mark Fasheh &lt;mfasheh@suse.de&gt;
Cc: Joseph Qi &lt;joseph.qi@huawei.com&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&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>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs</title>
<updated>2015-03-06T21:52:54+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-03-06T21:52:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=84399bb075a6fe320d4221970dc36314e46229fe'/>
<id>84399bb075a6fe320d4221970dc36314e46229fe</id>
<content type='text'>
Pull btrfs fixes from Chris Mason:
 "Outside of misc fixes, Filipe has a few fsync corners and we're
  pulling in one more of Josef's fixes from production use here"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs:__add_inode_ref: out of bounds memory read when looking for extended ref.
  Btrfs: fix data loss in the fast fsync path
  Btrfs: remove extra run_delayed_refs in update_cowonly_root
  Btrfs: incremental send, don't rename a directory too soon
  btrfs: fix lost return value due to variable shadowing
  Btrfs: do not ignore errors from btrfs_lookup_xattr in do_setxattr
  Btrfs: fix off-by-one logic error in btrfs_realloc_node
  Btrfs: add missing inode update when punching hole
  Btrfs: abort the transaction if we fail to update the free space cache inode
  Btrfs: fix fsync race leading to ordered extent memory leaks
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull btrfs fixes from Chris Mason:
 "Outside of misc fixes, Filipe has a few fsync corners and we're
  pulling in one more of Josef's fixes from production use here"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs:__add_inode_ref: out of bounds memory read when looking for extended ref.
  Btrfs: fix data loss in the fast fsync path
  Btrfs: remove extra run_delayed_refs in update_cowonly_root
  Btrfs: incremental send, don't rename a directory too soon
  btrfs: fix lost return value due to variable shadowing
  Btrfs: do not ignore errors from btrfs_lookup_xattr in do_setxattr
  Btrfs: fix off-by-one logic error in btrfs_realloc_node
  Btrfs: add missing inode update when punching hole
  Btrfs: abort the transaction if we fail to update the free space cache inode
  Btrfs: fix fsync race leading to ordered extent memory leaks
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'locks-v4.0-3' of git://git.samba.org/jlayton/linux</title>
<updated>2015-03-06T18:31:38+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-03-06T18:31:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7c5bde7adeba317d266b09db8ea9c3857eda86f5'/>
<id>7c5bde7adeba317d266b09db8ea9c3857eda86f5</id>
<content type='text'>
Pull file locking fix from Jeff Layton:
 "Just a single patch to fix a memory leak that Daniel Wagner discovered
  while doing some testing with leases"

* tag 'locks-v4.0-3' of git://git.samba.org/jlayton/linux:
  locks: fix fasync_struct memory leak in lease upgrade/downgrade handling
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull file locking fix from Jeff Layton:
 "Just a single patch to fix a memory leak that Daniel Wagner discovered
  while doing some testing with leases"

* tag 'locks-v4.0-3' of git://git.samba.org/jlayton/linux:
  locks: fix fasync_struct memory leak in lease upgrade/downgrade handling
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'nfs-for-4.0-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs</title>
<updated>2015-03-06T18:09:57+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-03-06T18:09:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1b1bd56191692e3a4a9079f469d9500005c89362'/>
<id>1b1bd56191692e3a4a9079f469d9500005c89362</id>
<content type='text'>
Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

   - Fix a regression in the NFSv4 open state recovery code
   - Fix a regression in the NFSv4 close code
   - Fix regressions and side-effects of the loop-back mounted NFS fixes
     in 3.18, that cause the NFS read() syscall to return EBUSY.
   - Fix regressions around the readdirplus code and how it interacts
     with the VFS lazy unmount changes that went into v3.18.
   - Fix issues with out-of-order RPC call replies replacing updated
     attributes with stale ones (particularly after a truncate()).
   - Fix an underflow checking issue with RPC/RDMA credits
   - Fix a number of issues with the NFSv4 delegation return/free code.
   - Fix issues around stale NFSv4.1 leases when doing a mount"

* tag 'nfs-for-4.0-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (24 commits)
  NFSv4.1: Clear the old state by our client id before establishing a new lease
  NFSv4: Fix a race in NFSv4.1 server trunking discovery
  NFS: Don't write enable new pages while an invalidation is proceeding
  NFS: Fix a regression in the read() syscall
  NFSv4: Ensure we skip delegations that are already being returned
  NFSv4: Pin the superblock while we're returning the delegation
  NFSv4: Ensure we honour NFS_DELEGATION_RETURNING in nfs_inode_set_delegation()
  NFSv4: Ensure that we don't reap a delegation that is being returned
  NFS: Fix stateid used for NFS v4 closes
  NFSv4: Don't call put_rpccred() under the rcu_read_lock()
  NFS: Don't require a filehandle to refresh the inode in nfs_prime_dcache()
  NFSv3: Use the readdir fileid as the mounted-on-fileid
  NFS: Don't invalidate a submounted dentry in nfs_prime_dcache()
  NFSv4: Set a barrier in the update_changeattr() helper
  NFS: Fix nfs_post_op_update_inode() to set an attribute barrier
  NFS: Remove size hack in nfs_inode_attrs_need_update()
  NFSv4: Add attribute update barriers to delegreturn and pNFS layoutcommit
  NFS: Add attribute update barriers to NFS writebacks
  NFS: Set an attribute barrier on all updates
  NFS: Add attribute update barriers to nfs_setattr_update_inode()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

   - Fix a regression in the NFSv4 open state recovery code
   - Fix a regression in the NFSv4 close code
   - Fix regressions and side-effects of the loop-back mounted NFS fixes
     in 3.18, that cause the NFS read() syscall to return EBUSY.
   - Fix regressions around the readdirplus code and how it interacts
     with the VFS lazy unmount changes that went into v3.18.
   - Fix issues with out-of-order RPC call replies replacing updated
     attributes with stale ones (particularly after a truncate()).
   - Fix an underflow checking issue with RPC/RDMA credits
   - Fix a number of issues with the NFSv4 delegation return/free code.
   - Fix issues around stale NFSv4.1 leases when doing a mount"

* tag 'nfs-for-4.0-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (24 commits)
  NFSv4.1: Clear the old state by our client id before establishing a new lease
  NFSv4: Fix a race in NFSv4.1 server trunking discovery
  NFS: Don't write enable new pages while an invalidation is proceeding
  NFS: Fix a regression in the read() syscall
  NFSv4: Ensure we skip delegations that are already being returned
  NFSv4: Pin the superblock while we're returning the delegation
  NFSv4: Ensure we honour NFS_DELEGATION_RETURNING in nfs_inode_set_delegation()
  NFSv4: Ensure that we don't reap a delegation that is being returned
  NFS: Fix stateid used for NFS v4 closes
  NFSv4: Don't call put_rpccred() under the rcu_read_lock()
  NFS: Don't require a filehandle to refresh the inode in nfs_prime_dcache()
  NFSv3: Use the readdir fileid as the mounted-on-fileid
  NFS: Don't invalidate a submounted dentry in nfs_prime_dcache()
  NFSv4: Set a barrier in the update_changeattr() helper
  NFS: Fix nfs_post_op_update_inode() to set an attribute barrier
  NFS: Remove size hack in nfs_inode_attrs_need_update()
  NFSv4: Add attribute update barriers to delegreturn and pNFS layoutcommit
  NFS: Add attribute update barriers to NFS writebacks
  NFS: Set an attribute barrier on all updates
  NFS: Add attribute update barriers to nfs_setattr_update_inode()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Btrfs:__add_inode_ref: out of bounds memory read when looking for extended ref.</title>
<updated>2015-03-06T01:28:33+00:00</updated>
<author>
<name>Quentin Casasnovas</name>
<email>quentin.casasnovas@oracle.com</email>
</author>
<published>2015-03-03T15:31:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=dd9ef135e3542ffc621c4eb7f0091870ec7a1504'/>
<id>dd9ef135e3542ffc621c4eb7f0091870ec7a1504</id>
<content type='text'>
Improper arithmetics when calculting the address of the extended ref could
lead to an out of bounds memory read and kernel panic.

Signed-off-by: Quentin Casasnovas &lt;quentin.casasnovas@oracle.com&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.cz&gt;
cc: stable@vger.kernel.org # v3.7+
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Improper arithmetics when calculting the address of the extended ref could
lead to an out of bounds memory read and kernel panic.

Signed-off-by: Quentin Casasnovas &lt;quentin.casasnovas@oracle.com&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.cz&gt;
cc: stable@vger.kernel.org # v3.7+
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Btrfs: fix data loss in the fast fsync path</title>
<updated>2015-03-06T01:28:32+00:00</updated>
<author>
<name>Filipe Manana</name>
<email>fdmanana@suse.com</email>
</author>
<published>2015-03-01T20:36:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3a8b36f378060d20062a0918e99fae39ff077bf0'/>
<id>3a8b36f378060d20062a0918e99fae39ff077bf0</id>
<content type='text'>
When using the fast file fsync code path we can miss the fact that new
writes happened since the last file fsync and therefore return without
waiting for the IO to finish and write the new extents to the fsync log.

Here's an example scenario where the fsync will miss the fact that new
file data exists that wasn't yet durably persisted:

1. fs_info-&gt;last_trans_committed == N - 1 and current transaction is
   transaction N (fs_info-&gt;generation == N);

2. do a buffered write;

3. fsync our inode, this clears our inode's full sync flag, starts
   an ordered extent and waits for it to complete - when it completes
   at btrfs_finish_ordered_io(), the inode's last_trans is set to the
   value N (via btrfs_update_inode_fallback -&gt; btrfs_update_inode -&gt;
   btrfs_set_inode_last_trans);

4. transaction N is committed, so fs_info-&gt;last_trans_committed is now
   set to the value N and fs_info-&gt;generation remains with the value N;

5. do another buffered write, when this happens btrfs_file_write_iter
   sets our inode's last_trans to the value N + 1 (that is
   fs_info-&gt;generation + 1 == N + 1);

6. transaction N + 1 is started and fs_info-&gt;generation now has the
   value N + 1;

7. transaction N + 1 is committed, so fs_info-&gt;last_trans_committed
   is set to the value N + 1;

8. fsync our inode - because it doesn't have the full sync flag set,
   we only start the ordered extent, we don't wait for it to complete
   (only in a later phase) therefore its last_trans field has the
   value N + 1 set previously by btrfs_file_write_iter(), and so we
   have:

       inode-&gt;last_trans &lt;= fs_info-&gt;last_trans_committed
           (N + 1)              (N + 1)

   Which made us not log the last buffered write and exit the fsync
   handler immediately, returning success (0) to user space and resulting
   in data loss after a crash.

This can actually be triggered deterministically and the following excerpt
from a testcase I made for xfstests triggers the issue. It moves a dummy
file across directories and then fsyncs the old parent directory - this
is just to trigger a transaction commit, so moving files around isn't
directly related to the issue but it was chosen because running 'sync' for
example does more than just committing the current transaction, as it
flushes/waits for all file data to be persisted. The issue can also happen
at random periods, since the transaction kthread periodicaly commits the
current transaction (about every 30 seconds by default).
The body of the test is:

  _scratch_mkfs &gt;&gt; $seqres.full 2&gt;&amp;1
  _init_flakey
  _mount_flakey

  # Create our main test file 'foo', the one we check for data loss.
  # By doing an fsync against our file, it makes btrfs clear the 'needs_full_sync'
  # bit from its flags (btrfs inode specific flags).
  $XFS_IO_PROG -f -c "pwrite -S 0xaa 0 8K" \
                  -c "fsync" $SCRATCH_MNT/foo | _filter_xfs_io

  # Now create one other file and 2 directories. We will move this second file
  # from one directory to the other later because it forces btrfs to commit its
  # currently open transaction if we fsync the old parent directory. This is
  # necessary to trigger the data loss bug that affected btrfs.
  mkdir $SCRATCH_MNT/testdir_1
  touch $SCRATCH_MNT/testdir_1/bar
  mkdir $SCRATCH_MNT/testdir_2

  # Make sure everything is durably persisted.
  sync

  # Write more 8Kb of data to our file.
  $XFS_IO_PROG -c "pwrite -S 0xbb 8K 8K" $SCRATCH_MNT/foo | _filter_xfs_io

  # Move our 'bar' file into a new directory.
  mv $SCRATCH_MNT/testdir_1/bar $SCRATCH_MNT/testdir_2/bar

  # Fsync our first directory. Because it had a file moved into some other
  # directory, this made btrfs commit the currently open transaction. This is
  # a condition necessary to trigger the data loss bug.
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/testdir_1

  # Now fsync our main test file. If the fsync succeeds, we expect the 8Kb of
  # data we wrote previously to be persisted and available if a crash happens.
  # This did not happen with btrfs, because of the transaction commit that
  # happened when we fsynced the parent directory.
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo

  # Simulate a crash/power loss.
  _load_flakey_table $FLAKEY_DROP_WRITES
  _unmount_flakey

  _load_flakey_table $FLAKEY_ALLOW_WRITES
  _mount_flakey

  # Now check that all data we wrote before are available.
  echo "File content after log replay:"
  od -t x1 $SCRATCH_MNT/foo

  status=0
  exit

The expected golden output for the test, which is what we get with this
fix applied (or when running against ext3/4 and xfs), is:

  wrote 8192/8192 bytes at offset 0
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  wrote 8192/8192 bytes at offset 8192
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  File content after log replay:
  0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
  *
  0020000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
  *
  0040000

Without this fix applied, the output shows the test file does not have
the second 8Kb extent that we successfully fsynced:

  wrote 8192/8192 bytes at offset 0
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  wrote 8192/8192 bytes at offset 8192
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  File content after log replay:
  0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
  *
  0020000

So fix this by skipping the fsync only if we're doing a full sync and
if the inode's last_trans is &lt;= fs_info-&gt;last_trans_committed, or if
the inode is already in the log. Also remove setting the inode's
last_trans in btrfs_file_write_iter since it's useless/unreliable.

Also because btrfs_file_write_iter no longer sets inode-&gt;last_trans to
fs_info-&gt;generation + 1, don't set last_trans to 0 if we bail out and don't
bail out if last_trans is 0, otherwise something as simple as the following
example wouldn't log the second write on the last fsync:

  1. write to file

  2. fsync file

  3. fsync file
       |--&gt; btrfs_inode_in_log() returns true and it set last_trans to 0

  4. write to file
       |--&gt; btrfs_file_write_iter() no longers sets last_trans, so it
            remained with a value of 0
  5. fsync
       |--&gt; inode-&gt;last_trans == 0, so it bails out without logging the
            second write

A test case for xfstests will be sent soon.

CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Filipe Manana &lt;fdmanana@suse.com&gt;
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When using the fast file fsync code path we can miss the fact that new
writes happened since the last file fsync and therefore return without
waiting for the IO to finish and write the new extents to the fsync log.

Here's an example scenario where the fsync will miss the fact that new
file data exists that wasn't yet durably persisted:

1. fs_info-&gt;last_trans_committed == N - 1 and current transaction is
   transaction N (fs_info-&gt;generation == N);

2. do a buffered write;

3. fsync our inode, this clears our inode's full sync flag, starts
   an ordered extent and waits for it to complete - when it completes
   at btrfs_finish_ordered_io(), the inode's last_trans is set to the
   value N (via btrfs_update_inode_fallback -&gt; btrfs_update_inode -&gt;
   btrfs_set_inode_last_trans);

4. transaction N is committed, so fs_info-&gt;last_trans_committed is now
   set to the value N and fs_info-&gt;generation remains with the value N;

5. do another buffered write, when this happens btrfs_file_write_iter
   sets our inode's last_trans to the value N + 1 (that is
   fs_info-&gt;generation + 1 == N + 1);

6. transaction N + 1 is started and fs_info-&gt;generation now has the
   value N + 1;

7. transaction N + 1 is committed, so fs_info-&gt;last_trans_committed
   is set to the value N + 1;

8. fsync our inode - because it doesn't have the full sync flag set,
   we only start the ordered extent, we don't wait for it to complete
   (only in a later phase) therefore its last_trans field has the
   value N + 1 set previously by btrfs_file_write_iter(), and so we
   have:

       inode-&gt;last_trans &lt;= fs_info-&gt;last_trans_committed
           (N + 1)              (N + 1)

   Which made us not log the last buffered write and exit the fsync
   handler immediately, returning success (0) to user space and resulting
   in data loss after a crash.

This can actually be triggered deterministically and the following excerpt
from a testcase I made for xfstests triggers the issue. It moves a dummy
file across directories and then fsyncs the old parent directory - this
is just to trigger a transaction commit, so moving files around isn't
directly related to the issue but it was chosen because running 'sync' for
example does more than just committing the current transaction, as it
flushes/waits for all file data to be persisted. The issue can also happen
at random periods, since the transaction kthread periodicaly commits the
current transaction (about every 30 seconds by default).
The body of the test is:

  _scratch_mkfs &gt;&gt; $seqres.full 2&gt;&amp;1
  _init_flakey
  _mount_flakey

  # Create our main test file 'foo', the one we check for data loss.
  # By doing an fsync against our file, it makes btrfs clear the 'needs_full_sync'
  # bit from its flags (btrfs inode specific flags).
  $XFS_IO_PROG -f -c "pwrite -S 0xaa 0 8K" \
                  -c "fsync" $SCRATCH_MNT/foo | _filter_xfs_io

  # Now create one other file and 2 directories. We will move this second file
  # from one directory to the other later because it forces btrfs to commit its
  # currently open transaction if we fsync the old parent directory. This is
  # necessary to trigger the data loss bug that affected btrfs.
  mkdir $SCRATCH_MNT/testdir_1
  touch $SCRATCH_MNT/testdir_1/bar
  mkdir $SCRATCH_MNT/testdir_2

  # Make sure everything is durably persisted.
  sync

  # Write more 8Kb of data to our file.
  $XFS_IO_PROG -c "pwrite -S 0xbb 8K 8K" $SCRATCH_MNT/foo | _filter_xfs_io

  # Move our 'bar' file into a new directory.
  mv $SCRATCH_MNT/testdir_1/bar $SCRATCH_MNT/testdir_2/bar

  # Fsync our first directory. Because it had a file moved into some other
  # directory, this made btrfs commit the currently open transaction. This is
  # a condition necessary to trigger the data loss bug.
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/testdir_1

  # Now fsync our main test file. If the fsync succeeds, we expect the 8Kb of
  # data we wrote previously to be persisted and available if a crash happens.
  # This did not happen with btrfs, because of the transaction commit that
  # happened when we fsynced the parent directory.
  $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo

  # Simulate a crash/power loss.
  _load_flakey_table $FLAKEY_DROP_WRITES
  _unmount_flakey

  _load_flakey_table $FLAKEY_ALLOW_WRITES
  _mount_flakey

  # Now check that all data we wrote before are available.
  echo "File content after log replay:"
  od -t x1 $SCRATCH_MNT/foo

  status=0
  exit

The expected golden output for the test, which is what we get with this
fix applied (or when running against ext3/4 and xfs), is:

  wrote 8192/8192 bytes at offset 0
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  wrote 8192/8192 bytes at offset 8192
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  File content after log replay:
  0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
  *
  0020000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
  *
  0040000

Without this fix applied, the output shows the test file does not have
the second 8Kb extent that we successfully fsynced:

  wrote 8192/8192 bytes at offset 0
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  wrote 8192/8192 bytes at offset 8192
  XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  File content after log replay:
  0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
  *
  0020000

So fix this by skipping the fsync only if we're doing a full sync and
if the inode's last_trans is &lt;= fs_info-&gt;last_trans_committed, or if
the inode is already in the log. Also remove setting the inode's
last_trans in btrfs_file_write_iter since it's useless/unreliable.

Also because btrfs_file_write_iter no longer sets inode-&gt;last_trans to
fs_info-&gt;generation + 1, don't set last_trans to 0 if we bail out and don't
bail out if last_trans is 0, otherwise something as simple as the following
example wouldn't log the second write on the last fsync:

  1. write to file

  2. fsync file

  3. fsync file
       |--&gt; btrfs_inode_in_log() returns true and it set last_trans to 0

  4. write to file
       |--&gt; btrfs_file_write_iter() no longers sets last_trans, so it
            remained with a value of 0
  5. fsync
       |--&gt; inode-&gt;last_trans == 0, so it bails out without logging the
            second write

A test case for xfstests will be sent soon.

CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Filipe Manana &lt;fdmanana@suse.com&gt;
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Btrfs: remove extra run_delayed_refs in update_cowonly_root</title>
<updated>2015-03-06T01:28:30+00:00</updated>
<author>
<name>Josef Bacik</name>
<email>jbacik@fb.com</email>
</author>
<published>2015-03-02T17:51:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f5c0a122800c301eecef93275b0c5d58bb4c15d9'/>
<id>f5c0a122800c301eecef93275b0c5d58bb4c15d9</id>
<content type='text'>
This got added with my dirty_bgs patch, it's not needed.  Thanks,

Signed-off-by: Josef Bacik &lt;jbacik@fb.com&gt;
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This got added with my dirty_bgs patch, it's not needed.  Thanks,

Signed-off-by: Josef Bacik &lt;jbacik@fb.com&gt;
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
