<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs, branch v5.3.4</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>CIFS: Fix oplock handling for SMB 2.1+ protocols</title>
<updated>2019-10-05T13:12:37+00:00</updated>
<author>
<name>Pavel Shilovsky</name>
<email>pshilov@microsoft.com</email>
</author>
<published>2019-09-26T19:31:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4e679ab4b95aee9eae6f6a2fc60b9072389d6fb7'/>
<id>4e679ab4b95aee9eae6f6a2fc60b9072389d6fb7</id>
<content type='text'>
commit a016e2794fc3a245a91946038dd8f34d65e53cc3 upstream.

There may be situations when a server negotiates SMB 2.1
protocol version or higher but responds to a CREATE request
with an oplock rather than a lease.

Currently the client doesn't handle such a case correctly:
when another CREATE comes in the server sends an oplock
break to the initial CREATE and the client doesn't send
an ack back due to a wrong caching level being set (READ
instead of RWH). Missing an oplock break ack makes the
server wait until the break times out which dramatically
increases the latency of the second CREATE.

Fix this by properly detecting oplocks when using SMB 2.1
protocol version and higher.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Pavel Shilovsky &lt;pshilov@microsoft.com&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
Reviewed-by: Ronnie Sahlberg &lt;lsahlber@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a016e2794fc3a245a91946038dd8f34d65e53cc3 upstream.

There may be situations when a server negotiates SMB 2.1
protocol version or higher but responds to a CREATE request
with an oplock rather than a lease.

Currently the client doesn't handle such a case correctly:
when another CREATE comes in the server sends an oplock
break to the initial CREATE and the client doesn't send
an ack back due to a wrong caching level being set (READ
instead of RWH). Missing an oplock break ack makes the
server wait until the break times out which dramatically
increases the latency of the second CREATE.

Fix this by properly detecting oplocks when using SMB 2.1
protocol version and higher.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Pavel Shilovsky &lt;pshilov@microsoft.com&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
Reviewed-by: Ronnie Sahlberg &lt;lsahlber@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>CIFS: fix max ea value size</title>
<updated>2019-10-05T13:12:36+00:00</updated>
<author>
<name>Murphy Zhou</name>
<email>jencce.kernel@gmail.com</email>
</author>
<published>2019-09-21T11:26:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9ea37d18a5bbedea0c65fcfa7c97ddec13ea618b'/>
<id>9ea37d18a5bbedea0c65fcfa7c97ddec13ea618b</id>
<content type='text'>
commit 63d37fb4ce5ae7bf1e58f906d1bf25f036fe79b2 upstream.

It should not be larger then the slab max buf size. If user
specifies a larger size, it passes this check and goes
straightly to SMB2_set_info_init performing an insecure memcpy.

Signed-off-by: Murphy Zhou &lt;jencce.kernel@gmail.com&gt;
Reviewed-by: Aurelien Aptel &lt;aaptel@suse.com&gt;
CC: Stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 63d37fb4ce5ae7bf1e58f906d1bf25f036fe79b2 upstream.

It should not be larger then the slab max buf size. If user
specifies a larger size, it passes this check and goes
straightly to SMB2_set_info_init performing an insecure memcpy.

Signed-off-by: Murphy Zhou &lt;jencce.kernel@gmail.com&gt;
Reviewed-by: Aurelien Aptel &lt;aaptel@suse.com&gt;
CC: Stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: fix punch hole for inline_data file systems</title>
<updated>2019-10-05T13:12:35+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2019-08-24T02:38:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d92c8d1e740efcbf1bcde236ed8b8397aed88e4d'/>
<id>d92c8d1e740efcbf1bcde236ed8b8397aed88e4d</id>
<content type='text'>
commit c1e8220bd316d8ae8e524df39534b8a412a45d5e upstream.

If a program attempts to punch a hole on an inline data file, we need
to convert it to a normal file first.

This was detected using ext4/032 using the adv configuration.  Simple
reproducer:

mke2fs -Fq -t ext4 -O inline_data /dev/vdc
mount /vdc
echo "" &gt; /vdc/testfile
xfs_io -c 'truncate 33554432' /vdc/testfile
xfs_io -c 'fpunch 0 1048576' /vdc/testfile
umount /vdc
e2fsck -fy /dev/vdc

Cc: stable@vger.kernel.org
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c1e8220bd316d8ae8e524df39534b8a412a45d5e upstream.

If a program attempts to punch a hole on an inline data file, we need
to convert it to a normal file first.

This was detected using ext4/032 using the adv configuration.  Simple
reproducer:

mke2fs -Fq -t ext4 -O inline_data /dev/vdc
mount /vdc
echo "" &gt; /vdc/testfile
xfs_io -c 'truncate 33554432' /vdc/testfile
xfs_io -c 'fpunch 0 1048576' /vdc/testfile
umount /vdc
e2fsck -fy /dev/vdc

Cc: stable@vger.kernel.org
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: fix warning inside ext4_convert_unwritten_extents_endio</title>
<updated>2019-10-05T13:12:35+00:00</updated>
<author>
<name>Rakesh Pandit</name>
<email>rakesh@tuxera.com</email>
</author>
<published>2019-08-23T02:53:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7587f2a2a93da4069d2514eda96bbe11a71595b9'/>
<id>7587f2a2a93da4069d2514eda96bbe11a71595b9</id>
<content type='text'>
commit e3d550c2c4f2f3dba469bc3c4b83d9332b4e99e1 upstream.

Really enable warning when CONFIG_EXT4_DEBUG is set and fix missing
first argument.  This was introduced in commit ff95ec22cd7f ("ext4:
add warning to ext4_convert_unwritten_extents_endio") and splitting
extents inside endio would trigger it.

Fixes: ff95ec22cd7f ("ext4: add warning to ext4_convert_unwritten_extents_endio")
Signed-off-by: Rakesh Pandit &lt;rakesh@tuxera.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e3d550c2c4f2f3dba469bc3c4b83d9332b4e99e1 upstream.

Really enable warning when CONFIG_EXT4_DEBUG is set and fix missing
first argument.  This was introduced in commit ff95ec22cd7f ("ext4:
add warning to ext4_convert_unwritten_extents_endio") and splitting
extents inside endio would trigger it.

Fixes: ff95ec22cd7f ("ext4: add warning to ext4_convert_unwritten_extents_endio")
Signed-off-by: Rakesh Pandit &lt;rakesh@tuxera.com&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xfs: Fix stale data exposure when readahead races with hole punch</title>
<updated>2019-10-05T13:12:34+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2019-08-29T16:04:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ff6d7192d95268df6b18e745a5bd50d04c648bc6'/>
<id>ff6d7192d95268df6b18e745a5bd50d04c648bc6</id>
<content type='text'>
commit 40144e49ff84c3bd6bd091b58115257670be8803 upstream.

Hole puching currently evicts pages from page cache and then goes on to
remove blocks from the inode. This happens under both XFS_IOLOCK_EXCL
and XFS_MMAPLOCK_EXCL which provides appropriate serialization with
racing reads or page faults. However there is currently nothing that
prevents readahead triggered by fadvise() or madvise() from racing with
the hole punch and instantiating page cache page after hole punching has
evicted page cache in xfs_flush_unmap_range() but before it has removed
blocks from the inode. This page cache page will be mapping soon to be
freed block and that can lead to returning stale data to userspace or
even filesystem corruption.

Fix the problem by protecting handling of readahead requests by
XFS_IOLOCK_SHARED similarly as we protect reads.

CC: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxjQNmxqmtA_VbYW0Su9rKRk2zobJmahcyeaEVOFKVQ5dw@mail.gmail.com/
Reported-by: Amir Goldstein &lt;amir73il@gmail.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 40144e49ff84c3bd6bd091b58115257670be8803 upstream.

Hole puching currently evicts pages from page cache and then goes on to
remove blocks from the inode. This happens under both XFS_IOLOCK_EXCL
and XFS_MMAPLOCK_EXCL which provides appropriate serialization with
racing reads or page faults. However there is currently nothing that
prevents readahead triggered by fadvise() or madvise() from racing with
the hole punch and instantiating page cache page after hole punching has
evicted page cache in xfs_flush_unmap_range() but before it has removed
blocks from the inode. This page cache page will be mapping soon to be
freed block and that can lead to returning stale data to userspace or
even filesystem corruption.

Fix the problem by protecting handling of readahead requests by
XFS_IOLOCK_SHARED similarly as we protect reads.

CC: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxjQNmxqmtA_VbYW0Su9rKRk2zobJmahcyeaEVOFKVQ5dw@mail.gmail.com/
Reported-by: Amir Goldstein &lt;amir73il@gmail.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>btrfs: Fix a regression which we can't convert to SINGLE profile</title>
<updated>2019-10-05T13:12:32+00:00</updated>
<author>
<name>Qu Wenruo</name>
<email>wqu@suse.com</email>
</author>
<published>2019-09-25T02:13:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=773ded9d9853fc78c29a454250dacd0cc215798f'/>
<id>773ded9d9853fc78c29a454250dacd0cc215798f</id>
<content type='text'>
commit fab273595507a9ec7035df6d5512a955d80a80ba upstream.

[BUG]
With v5.3 kernel, we can't convert to SINGLE profile:

  # btrfs balance start -f -dconvert=single $mnt
  ERROR: error during balancing '/mnt/btrfs': Invalid argument
  # dmesg -t | tail
  validate_convert_profile: data profile=0x1000000000000 allowed=0x20 is_valid=1 final=0x1000000000000 ret=1
  BTRFS error (device dm-3): balance: invalid convert data profile single

[CAUSE]
With the extra debug output added, it shows that the @allowed bit is
lacking the special in-memory only SINGLE profile bit.

Thus we fail at that (profile &amp; ~allowed) check.

This regression is caused by commit 081db89b13cb ("btrfs: use raid_attr
to get allowed profiles for balance conversion") and the fact that we
don't use any bit to indicate SINGLE profile on-disk, but uses special
in-memory only bit to help distinguish different profiles.

[FIX]
Add that BTRFS_AVAIL_ALLOC_BIT_SINGLE to @allowed, so the code should be
the same as it was and fix the regression.

Reported-by: Chris Murphy &lt;lists@colorremedies.com&gt;
Fixes: 081db89b13cb ("btrfs: use raid_attr to get allowed profiles for balance conversion")
CC: stable@vger.kernel.org # 5.3+
Reviewed-by: Anand Jain &lt;anand.jain@oracle.com&gt;
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fab273595507a9ec7035df6d5512a955d80a80ba upstream.

[BUG]
With v5.3 kernel, we can't convert to SINGLE profile:

  # btrfs balance start -f -dconvert=single $mnt
  ERROR: error during balancing '/mnt/btrfs': Invalid argument
  # dmesg -t | tail
  validate_convert_profile: data profile=0x1000000000000 allowed=0x20 is_valid=1 final=0x1000000000000 ret=1
  BTRFS error (device dm-3): balance: invalid convert data profile single

[CAUSE]
With the extra debug output added, it shows that the @allowed bit is
lacking the special in-memory only SINGLE profile bit.

Thus we fail at that (profile &amp; ~allowed) check.

This regression is caused by commit 081db89b13cb ("btrfs: use raid_attr
to get allowed profiles for balance conversion") and the fact that we
don't use any bit to indicate SINGLE profile on-disk, but uses special
in-memory only bit to help distinguish different profiles.

[FIX]
Add that BTRFS_AVAIL_ALLOC_BIT_SINGLE to @allowed, so the code should be
the same as it was and fix the regression.

Reported-by: Chris Murphy &lt;lists@colorremedies.com&gt;
Fixes: 081db89b13cb ("btrfs: use raid_attr to get allowed profiles for balance conversion")
CC: stable@vger.kernel.org # 5.3+
Reviewed-by: Anand Jain &lt;anand.jain@oracle.com&gt;
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Reviewed-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Btrfs: fix race setting up and completing qgroup rescan workers</title>
<updated>2019-10-05T13:12:32+00:00</updated>
<author>
<name>Filipe Manana</name>
<email>fdmanana@suse.com</email>
</author>
<published>2019-09-24T09:49:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0e007f8e0dba65bb03c3ea0531fde29aa484ab00'/>
<id>0e007f8e0dba65bb03c3ea0531fde29aa484ab00</id>
<content type='text'>
commit 13fc1d271a2e3ab8a02071e711add01fab9271f6 upstream.

There is a race between setting up a qgroup rescan worker and completing
a qgroup rescan worker that can lead to callers of the qgroup rescan wait
ioctl to either not wait for the rescan worker to complete or to hang
forever due to missing wake ups. The following diagram shows a sequence
of steps that illustrates the race.

        CPU 1                                                         CPU 2                                  CPU 3

 btrfs_ioctl_quota_rescan()
  btrfs_qgroup_rescan()
   qgroup_rescan_init()
    mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)
    spin_lock(&amp;fs_info-&gt;qgroup_lock)

    fs_info-&gt;qgroup_flags |=
      BTRFS_QGROUP_STATUS_FLAG_RESCAN

    init_completion(
      &amp;fs_info-&gt;qgroup_rescan_completion)

    fs_info-&gt;qgroup_rescan_running = true

    mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)
    spin_unlock(&amp;fs_info-&gt;qgroup_lock)

    btrfs_init_work()
     --&gt; starts the worker

                                                        btrfs_qgroup_rescan_worker()
                                                         mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)

                                                         fs_info-&gt;qgroup_flags &amp;=
                                                           ~BTRFS_QGROUP_STATUS_FLAG_RESCAN

                                                         mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)

                                                         starts transaction, updates qgroup status
                                                         item, etc

                                                                                                           btrfs_ioctl_quota_rescan()
                                                                                                            btrfs_qgroup_rescan()
                                                                                                             qgroup_rescan_init()
                                                                                                              mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)
                                                                                                              spin_lock(&amp;fs_info-&gt;qgroup_lock)

                                                                                                              fs_info-&gt;qgroup_flags |=
                                                                                                                BTRFS_QGROUP_STATUS_FLAG_RESCAN

                                                                                                              init_completion(
                                                                                                                &amp;fs_info-&gt;qgroup_rescan_completion)

                                                                                                              fs_info-&gt;qgroup_rescan_running = true

                                                                                                              mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)
                                                                                                              spin_unlock(&amp;fs_info-&gt;qgroup_lock)

                                                                                                              btrfs_init_work()
                                                                                                               --&gt; starts another worker

                                                         mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)

                                                         fs_info-&gt;qgroup_rescan_running = false

                                                         mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)

							 complete_all(&amp;fs_info-&gt;qgroup_rescan_completion)

Before the rescan worker started by the task at CPU 3 completes, if
another task calls btrfs_ioctl_quota_rescan(), it will get -EINPROGRESS
because the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN is set at
fs_info-&gt;qgroup_flags, which is expected and correct behaviour.

However if other task calls btrfs_ioctl_quota_rescan_wait() before the
rescan worker started by the task at CPU 3 completes, it will return
immediately without waiting for the new rescan worker to complete,
because fs_info-&gt;qgroup_rescan_running is set to false by CPU 2.

This race is making test case btrfs/171 (from fstests) to fail often:

  btrfs/171 9s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad)
#      --- tests/btrfs/171.out     2018-09-16 21:30:48.505104287 +0100
#      +++ /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad      2019-09-19 02:01:36.938486039 +0100
#      @@ -1,2 +1,3 @@
#       QA output created by 171
#      +ERROR: quota rescan failed: Operation now in progress
#       Silence is golden
#      ...
#      (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/171.out /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad'  to see the entire diff)

That is because the test calls the btrfs-progs commands "qgroup quota
rescan -w", "qgroup assign" and "qgroup remove" in a sequence that makes
calls to the rescan start ioctl fail with -EINPROGRESS (note the "btrfs"
commands 'qgroup assign' and 'qgroup remove' often call the rescan start
ioctl after calling the qgroup assign ioctl,
btrfs_ioctl_qgroup_assign()), since previous waits didn't actually wait
for a rescan worker to complete.

Another problem the race can cause is missing wake ups for waiters,
since the call to complete_all() happens outside a critical section and
after clearing the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN. In the sequence
diagram above, if we have a waiter for the first rescan task (executed
by CPU 2), then fs_info-&gt;qgroup_rescan_completion.wait is not empty, and
if after the rescan worker clears BTRFS_QGROUP_STATUS_FLAG_RESCAN and
before it calls complete_all() against
fs_info-&gt;qgroup_rescan_completion, the task at CPU 3 calls
init_completion() against fs_info-&gt;qgroup_rescan_completion which
re-initilizes its wait queue to an empty queue, therefore causing the
rescan worker at CPU 2 to call complete_all() against an empty queue,
never waking up the task waiting for that rescan worker.

Fix this by clearing BTRFS_QGROUP_STATUS_FLAG_RESCAN and setting
fs_info-&gt;qgroup_rescan_running to false in the same critical section,
delimited by the mutex fs_info-&gt;qgroup_rescan_lock, as well as doing the
call to complete_all() in that same critical section. This gives the
protection needed to avoid rescan wait ioctl callers not waiting for a
running rescan worker and the lost wake ups problem, since setting that
rescan flag and boolean as well as initializing the wait queue is done
already in a critical section delimited by that mutex (at
qgroup_rescan_init()).

Fixes: 57254b6ebce4ce ("Btrfs: add ioctl to wait for qgroup rescan completion")
Fixes: d2c609b834d62f ("btrfs: properly track when rescan worker is running")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Signed-off-by: Filipe Manana &lt;fdmanana@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 13fc1d271a2e3ab8a02071e711add01fab9271f6 upstream.

There is a race between setting up a qgroup rescan worker and completing
a qgroup rescan worker that can lead to callers of the qgroup rescan wait
ioctl to either not wait for the rescan worker to complete or to hang
forever due to missing wake ups. The following diagram shows a sequence
of steps that illustrates the race.

        CPU 1                                                         CPU 2                                  CPU 3

 btrfs_ioctl_quota_rescan()
  btrfs_qgroup_rescan()
   qgroup_rescan_init()
    mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)
    spin_lock(&amp;fs_info-&gt;qgroup_lock)

    fs_info-&gt;qgroup_flags |=
      BTRFS_QGROUP_STATUS_FLAG_RESCAN

    init_completion(
      &amp;fs_info-&gt;qgroup_rescan_completion)

    fs_info-&gt;qgroup_rescan_running = true

    mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)
    spin_unlock(&amp;fs_info-&gt;qgroup_lock)

    btrfs_init_work()
     --&gt; starts the worker

                                                        btrfs_qgroup_rescan_worker()
                                                         mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)

                                                         fs_info-&gt;qgroup_flags &amp;=
                                                           ~BTRFS_QGROUP_STATUS_FLAG_RESCAN

                                                         mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)

                                                         starts transaction, updates qgroup status
                                                         item, etc

                                                                                                           btrfs_ioctl_quota_rescan()
                                                                                                            btrfs_qgroup_rescan()
                                                                                                             qgroup_rescan_init()
                                                                                                              mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)
                                                                                                              spin_lock(&amp;fs_info-&gt;qgroup_lock)

                                                                                                              fs_info-&gt;qgroup_flags |=
                                                                                                                BTRFS_QGROUP_STATUS_FLAG_RESCAN

                                                                                                              init_completion(
                                                                                                                &amp;fs_info-&gt;qgroup_rescan_completion)

                                                                                                              fs_info-&gt;qgroup_rescan_running = true

                                                                                                              mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)
                                                                                                              spin_unlock(&amp;fs_info-&gt;qgroup_lock)

                                                                                                              btrfs_init_work()
                                                                                                               --&gt; starts another worker

                                                         mutex_lock(&amp;fs_info-&gt;qgroup_rescan_lock)

                                                         fs_info-&gt;qgroup_rescan_running = false

                                                         mutex_unlock(&amp;fs_info-&gt;qgroup_rescan_lock)

							 complete_all(&amp;fs_info-&gt;qgroup_rescan_completion)

Before the rescan worker started by the task at CPU 3 completes, if
another task calls btrfs_ioctl_quota_rescan(), it will get -EINPROGRESS
because the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN is set at
fs_info-&gt;qgroup_flags, which is expected and correct behaviour.

However if other task calls btrfs_ioctl_quota_rescan_wait() before the
rescan worker started by the task at CPU 3 completes, it will return
immediately without waiting for the new rescan worker to complete,
because fs_info-&gt;qgroup_rescan_running is set to false by CPU 2.

This race is making test case btrfs/171 (from fstests) to fail often:

  btrfs/171 9s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad)
#      --- tests/btrfs/171.out     2018-09-16 21:30:48.505104287 +0100
#      +++ /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad      2019-09-19 02:01:36.938486039 +0100
#      @@ -1,2 +1,3 @@
#       QA output created by 171
#      +ERROR: quota rescan failed: Operation now in progress
#       Silence is golden
#      ...
#      (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/171.out /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad'  to see the entire diff)

That is because the test calls the btrfs-progs commands "qgroup quota
rescan -w", "qgroup assign" and "qgroup remove" in a sequence that makes
calls to the rescan start ioctl fail with -EINPROGRESS (note the "btrfs"
commands 'qgroup assign' and 'qgroup remove' often call the rescan start
ioctl after calling the qgroup assign ioctl,
btrfs_ioctl_qgroup_assign()), since previous waits didn't actually wait
for a rescan worker to complete.

Another problem the race can cause is missing wake ups for waiters,
since the call to complete_all() happens outside a critical section and
after clearing the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN. In the sequence
diagram above, if we have a waiter for the first rescan task (executed
by CPU 2), then fs_info-&gt;qgroup_rescan_completion.wait is not empty, and
if after the rescan worker clears BTRFS_QGROUP_STATUS_FLAG_RESCAN and
before it calls complete_all() against
fs_info-&gt;qgroup_rescan_completion, the task at CPU 3 calls
init_completion() against fs_info-&gt;qgroup_rescan_completion which
re-initilizes its wait queue to an empty queue, therefore causing the
rescan worker at CPU 2 to call complete_all() against an empty queue,
never waking up the task waiting for that rescan worker.

Fix this by clearing BTRFS_QGROUP_STATUS_FLAG_RESCAN and setting
fs_info-&gt;qgroup_rescan_running to false in the same critical section,
delimited by the mutex fs_info-&gt;qgroup_rescan_lock, as well as doing the
call to complete_all() in that same critical section. This gives the
protection needed to avoid rescan wait ioctl callers not waiting for a
running rescan worker and the lost wake ups problem, since setting that
rescan flag and boolean as well as initializing the wait queue is done
already in a critical section delimited by that mutex (at
qgroup_rescan_init()).

Fixes: 57254b6ebce4ce ("Btrfs: add ioctl to wait for qgroup rescan completion")
Fixes: d2c609b834d62f ("btrfs: properly track when rescan worker is running")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Signed-off-by: Filipe Manana &lt;fdmanana@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>btrfs: qgroup: Fix reserved data space leak if we have multiple reserve calls</title>
<updated>2019-10-05T13:12:32+00:00</updated>
<author>
<name>Qu Wenruo</name>
<email>wqu@suse.com</email>
</author>
<published>2019-09-16T12:02:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=88b870760d1912a1e4f94bae7ac9965f9a0da91e'/>
<id>88b870760d1912a1e4f94bae7ac9965f9a0da91e</id>
<content type='text'>
commit d4e204948fe3e0dc8e1fbf3f8f3290c9c2823be3 upstream.

[BUG]
The following script can cause btrfs qgroup data space leak:

  mkfs.btrfs -f $dev
  mount $dev -o nospace_cache $mnt

  btrfs subv create $mnt/subv
  btrfs quota en $mnt
  btrfs quota rescan -w $mnt
  btrfs qgroup limit 128m $mnt/subv

  for (( i = 0; i &lt; 3; i++)); do
          # Create 3 64M holes for latter fallocate to fail
          truncate -s 192m $mnt/subv/file
          xfs_io -c "pwrite 64m 4k" $mnt/subv/file &gt; /dev/null
          xfs_io -c "pwrite 128m 4k" $mnt/subv/file &gt; /dev/null
          sync

          # it's supposed to fail, and each failure will leak at least 64M
          # data space
          xfs_io -f -c "falloc 0 192m" $mnt/subv/file &amp;&gt; /dev/null
          rm $mnt/subv/file
          sync
  done

  # Shouldn't fail after we removed the file
  xfs_io -f -c "falloc 0 64m" $mnt/subv/file

[CAUSE]
Btrfs qgroup data reserve code allow multiple reservations to happen on
a single extent_changeset:
E.g:
	btrfs_qgroup_reserve_data(inode, &amp;data_reserved, 0, SZ_1M);
	btrfs_qgroup_reserve_data(inode, &amp;data_reserved, SZ_1M, SZ_2M);
	btrfs_qgroup_reserve_data(inode, &amp;data_reserved, 0, SZ_4M);

Btrfs qgroup code has its internal tracking to make sure we don't
double-reserve in above example.

The only pattern utilizing this feature is in the main while loop of
btrfs_fallocate() function.

However btrfs_qgroup_reserve_data()'s error handling has a bug in that
on error it clears all ranges in the io_tree with EXTENT_QGROUP_RESERVED
flag but doesn't free previously reserved bytes.

This bug has a two fold effect:
- Clearing EXTENT_QGROUP_RESERVED ranges
  This is the correct behavior, but it prevents
  btrfs_qgroup_check_reserved_leak() to catch the leakage as the
  detector is purely EXTENT_QGROUP_RESERVED flag based.

- Leak the previously reserved data bytes.

The bug manifests when N calls to btrfs_qgroup_reserve_data are made and
the last one fails, leaking space reserved in the previous ones.

[FIX]
Also free previously reserved data bytes when btrfs_qgroup_reserve_data
fails.

Fixes: 524725537023 ("btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d4e204948fe3e0dc8e1fbf3f8f3290c9c2823be3 upstream.

[BUG]
The following script can cause btrfs qgroup data space leak:

  mkfs.btrfs -f $dev
  mount $dev -o nospace_cache $mnt

  btrfs subv create $mnt/subv
  btrfs quota en $mnt
  btrfs quota rescan -w $mnt
  btrfs qgroup limit 128m $mnt/subv

  for (( i = 0; i &lt; 3; i++)); do
          # Create 3 64M holes for latter fallocate to fail
          truncate -s 192m $mnt/subv/file
          xfs_io -c "pwrite 64m 4k" $mnt/subv/file &gt; /dev/null
          xfs_io -c "pwrite 128m 4k" $mnt/subv/file &gt; /dev/null
          sync

          # it's supposed to fail, and each failure will leak at least 64M
          # data space
          xfs_io -f -c "falloc 0 192m" $mnt/subv/file &amp;&gt; /dev/null
          rm $mnt/subv/file
          sync
  done

  # Shouldn't fail after we removed the file
  xfs_io -f -c "falloc 0 64m" $mnt/subv/file

[CAUSE]
Btrfs qgroup data reserve code allow multiple reservations to happen on
a single extent_changeset:
E.g:
	btrfs_qgroup_reserve_data(inode, &amp;data_reserved, 0, SZ_1M);
	btrfs_qgroup_reserve_data(inode, &amp;data_reserved, SZ_1M, SZ_2M);
	btrfs_qgroup_reserve_data(inode, &amp;data_reserved, 0, SZ_4M);

Btrfs qgroup code has its internal tracking to make sure we don't
double-reserve in above example.

The only pattern utilizing this feature is in the main while loop of
btrfs_fallocate() function.

However btrfs_qgroup_reserve_data()'s error handling has a bug in that
on error it clears all ranges in the io_tree with EXTENT_QGROUP_RESERVED
flag but doesn't free previously reserved bytes.

This bug has a two fold effect:
- Clearing EXTENT_QGROUP_RESERVED ranges
  This is the correct behavior, but it prevents
  btrfs_qgroup_check_reserved_leak() to catch the leakage as the
  detector is purely EXTENT_QGROUP_RESERVED flag based.

- Leak the previously reserved data bytes.

The bug manifests when N calls to btrfs_qgroup_reserve_data are made and
the last one fails, leaking space reserved in the previous ones.

[FIX]
Also free previously reserved data bytes when btrfs_qgroup_reserve_data
fails.

Fixes: 524725537023 ("btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>btrfs: qgroup: Fix the wrong target io_tree when freeing reserved data space</title>
<updated>2019-10-05T13:12:31+00:00</updated>
<author>
<name>Qu Wenruo</name>
<email>wqu@suse.com</email>
</author>
<published>2019-09-16T12:02:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=53daf6b7a0117b0d8aa54f2e65878fb7f4477bd0'/>
<id>53daf6b7a0117b0d8aa54f2e65878fb7f4477bd0</id>
<content type='text'>
commit bab32fc069ce8829c416e8737c119f62a57970f9 upstream.

[BUG]
Under the following case with qgroup enabled, if some error happened
after we have reserved delalloc space, then in error handling path, we
could cause qgroup data space leakage:

From btrfs_truncate_block() in inode.c:

	ret = btrfs_delalloc_reserve_space(inode, &amp;data_reserved,
					   block_start, blocksize);
	if (ret)
		goto out;

 again:
	page = find_or_create_page(mapping, index, mask);
	if (!page) {
		btrfs_delalloc_release_space(inode, data_reserved,
					     block_start, blocksize, true);
		btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true);
		ret = -ENOMEM;
		goto out;
	}

[CAUSE]
In the above case, btrfs_delalloc_reserve_space() will call
btrfs_qgroup_reserve_data() and mark the io_tree range with
EXTENT_QGROUP_RESERVED flag.

In the error handling path, we have the following call stack:
btrfs_delalloc_release_space()
|- btrfs_free_reserved_data_space()
   |- btrsf_qgroup_free_data()
      |- __btrfs_qgroup_release_data(reserved=@reserved, free=1)
         |- qgroup_free_reserved_data(reserved=@reserved)
            |- clear_record_extent_bits();
            |- freed += changeset.bytes_changed;

However due to a completion bug, qgroup_free_reserved_data() will clear
EXTENT_QGROUP_RESERVED flag in BTRFS_I(inode)-&gt;io_failure_tree, other
than the correct BTRFS_I(inode)-&gt;io_tree.
Since io_failure_tree is never marked with that flag,
btrfs_qgroup_free_data() will not free any data reserved space at all,
causing a leakage.

This type of error handling can only be triggered by errors outside of
qgroup code. So EDQUOT error from qgroup can't trigger it.

[FIX]
Fix the wrong target io_tree.

Reported-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Fixes: bc42bda22345 ("btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Nikolay Borisov &lt;nborisov@suse.com&gt;
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit bab32fc069ce8829c416e8737c119f62a57970f9 upstream.

[BUG]
Under the following case with qgroup enabled, if some error happened
after we have reserved delalloc space, then in error handling path, we
could cause qgroup data space leakage:

From btrfs_truncate_block() in inode.c:

	ret = btrfs_delalloc_reserve_space(inode, &amp;data_reserved,
					   block_start, blocksize);
	if (ret)
		goto out;

 again:
	page = find_or_create_page(mapping, index, mask);
	if (!page) {
		btrfs_delalloc_release_space(inode, data_reserved,
					     block_start, blocksize, true);
		btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true);
		ret = -ENOMEM;
		goto out;
	}

[CAUSE]
In the above case, btrfs_delalloc_reserve_space() will call
btrfs_qgroup_reserve_data() and mark the io_tree range with
EXTENT_QGROUP_RESERVED flag.

In the error handling path, we have the following call stack:
btrfs_delalloc_release_space()
|- btrfs_free_reserved_data_space()
   |- btrsf_qgroup_free_data()
      |- __btrfs_qgroup_release_data(reserved=@reserved, free=1)
         |- qgroup_free_reserved_data(reserved=@reserved)
            |- clear_record_extent_bits();
            |- freed += changeset.bytes_changed;

However due to a completion bug, qgroup_free_reserved_data() will clear
EXTENT_QGROUP_RESERVED flag in BTRFS_I(inode)-&gt;io_failure_tree, other
than the correct BTRFS_I(inode)-&gt;io_tree.
Since io_failure_tree is never marked with that flag,
btrfs_qgroup_free_data() will not free any data reserved space at all,
causing a leakage.

This type of error handling can only be triggered by errors outside of
qgroup code. So EDQUOT error from qgroup can't trigger it.

[FIX]
Fix the wrong target io_tree.

Reported-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Fixes: bc42bda22345 ("btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Nikolay Borisov &lt;nborisov@suse.com&gt;
Signed-off-by: Qu Wenruo &lt;wqu@suse.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>btrfs: adjust dirty_metadata_bytes after writeback failure of extent buffer</title>
<updated>2019-10-05T13:12:31+00:00</updated>
<author>
<name>Dennis Zhou</name>
<email>dennis@kernel.org</email>
</author>
<published>2019-09-13T13:54:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=79b8b06b726c17525140fa5b1376a8f4b8a78249'/>
<id>79b8b06b726c17525140fa5b1376a8f4b8a78249</id>
<content type='text'>
commit eb5b64f142504a597d67e2109d603055ff765e52 upstream.

Before, if a eb failed to write out, we would end up triggering a
BUG_ON(). As of f4340622e0226 ("btrfs: extent_io: Move the BUG_ON() in
flush_write_bio() one level up"), we no longer BUG_ON(), so we should
make life consistent and add back the unwritten bytes to
dirty_metadata_bytes.

Fixes: f4340622e022 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Filipe Manana &lt;fdmanana@kernel.org&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit eb5b64f142504a597d67e2109d603055ff765e52 upstream.

Before, if a eb failed to write out, we would end up triggering a
BUG_ON(). As of f4340622e0226 ("btrfs: extent_io: Move the BUG_ON() in
flush_write_bio() one level up"), we no longer BUG_ON(), so we should
make life consistent and add back the unwritten bytes to
dirty_metadata_bytes.

Fixes: f4340622e022 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Filipe Manana &lt;fdmanana@kernel.org&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
