<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/fs, branch v5.4.50</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v5.4.50</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v5.4.50'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2020-06-30T19:37:13+00:00</updated>
<entry>
<title>xfs: add agf freeblocks verify in xfs_agf_verify</title>
<updated>2020-06-30T19:37:13+00:00</updated>
<author>
<name>Zheng Bin</name>
<email>zhengbin13@huawei.com</email>
</author>
<published>2020-02-21T15:38:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=ffd40b7962d463daa531a8110e5b708bcb5c6da7'/>
<id>urn:sha1:ffd40b7962d463daa531a8110e5b708bcb5c6da7</id>
<content type='text'>
[ Upstream commit d0c7feaf87678371c2c09b3709400be416b2dc62 ]

We recently used fuzz(hydra) to test XFS and automatically generate
tmp.img(XFS v5 format, but some metadata is wrong)

xfs_repair information(just one AG):
agf_freeblks 0, counted 3224 in ag 0
agf_longest 536874136, counted 3224 in ag 0
sb_fdblocks 613, counted 3228

Test as follows:
mount tmp.img tmpdir
cp file1M tmpdir
sync

In 4.19-stable, sync will stuck, the reason is:
xfs_mountfs
  xfs_check_summary_counts
    if ((!xfs_sb_version_haslazysbcount(&amp;mp-&gt;m_sb) ||
       XFS_LAST_UNMOUNT_WAS_CLEAN(mp)) &amp;&amp;
       !xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS))
	return 0;  --&gt;just return, incore sb_fdblocks still be 613
    xfs_initialize_perag_data

cp file1M tmpdir --&gt;ok(write file to pagecache)
sync --&gt;stuck(write pagecache to disk)
xfs_map_blocks
  xfs_iomap_write_allocate
    while (count_fsb != 0) {
      nimaps = 0;
      while (nimaps == 0) { --&gt; endless loop
         nimaps = 1;
         xfs_bmapi_write(..., &amp;nimaps) --&gt; nimaps becomes 0 again
xfs_bmapi_write
  xfs_bmap_alloc
    xfs_bmap_btalloc
      xfs_alloc_vextent
        xfs_alloc_fix_freelist
          xfs_alloc_space_available --&gt;fail(agf_freeblks is 0)

In linux-next, sync not stuck, cause commit c2b3164320b5 ("xfs:
use the latest extent at writeback delalloc conversion time") remove
the above while, dmesg is as follows:
[   55.250114] XFS (loop0): page discard on page ffffea0008bc7380, inode 0x1b0c, offset 0.

Users do not know why this page is discard, the better soultion is:
1. Like xfs_repair, make sure sb_fdblocks is equal to counted
(xfs_initialize_perag_data did this, who is not called at this mount)
2. Add agf verify, if fail, will tell users to repair

This patch use the second soultion.

Signed-off-by: Zheng Bin &lt;zhengbin13@huawei.com&gt;
Signed-off-by: Ren Xudong &lt;renxudong1@huawei.com&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: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>NFSv4 fix CLOSE not waiting for direct IO compeletion</title>
<updated>2020-06-30T19:37:12+00:00</updated>
<author>
<name>Olga Kornievskaia</name>
<email>olga.kornievskaia@gmail.com</email>
</author>
<published>2020-06-24T17:54:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4d35ca872ac3c7464f062231f6a55444dbbcc106'/>
<id>urn:sha1:4d35ca872ac3c7464f062231f6a55444dbbcc106</id>
<content type='text'>
commit d03727b248d0dae6199569a8d7b629a681154633 upstream.

Figuring out the root case for the REMOVE/CLOSE race and
suggesting the solution was done by Neil Brown.

Currently what happens is that direct IO calls hold a reference
on the open context which is decremented as an asynchronous task
in the nfs_direct_complete(). Before reference is decremented,
control is returned to the application which is free to close the
file. When close is being processed, it decrements its reference
on the open_context but since directIO still holds one, it doesn't
sent a close on the wire. It returns control to the application
which is free to do other operations. For instance, it can delete a
file. Direct IO is finally releasing its reference and triggering
an asynchronous close. Which races with the REMOVE. On the server,
REMOVE can be processed before the CLOSE, failing the REMOVE with
EACCES as the file is still opened.

Signed-off-by: Olga Kornievskaia &lt;kolga@netapp.com&gt;
Suggested-by: Neil Brown &lt;neilb@suse.com&gt;
CC: stable@vger.kernel.org
Signed-off-by: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>pNFS/flexfiles: Fix list corruption if the mirror count changes</title>
<updated>2020-06-30T19:37:12+00:00</updated>
<author>
<name>Trond Myklebust</name>
<email>trond.myklebust@hammerspace.com</email>
</author>
<published>2020-06-22T19:04:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=02917bef8f1b08cde7027446177c5cb288456f99'/>
<id>urn:sha1:02917bef8f1b08cde7027446177c5cb288456f99</id>
<content type='text'>
commit 8b04013737341442ed914b336cde866b902664ae upstream.

If the mirror count changes in the new layout we pick up inside
ff_layout_pg_init_write(), then we can end up adding the
request to the wrong mirror and corrupting the mirror-&gt;pg_list.

Fixes: d600ad1f2bdb ("NFS41: pop some layoutget errors to application")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Signed-off-by: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ocfs2: fix panic on nfs server over ocfs2</title>
<updated>2020-06-30T19:37:09+00:00</updated>
<author>
<name>Junxiao Bi</name>
<email>junxiao.bi@oracle.com</email>
</author>
<published>2020-06-26T03:29:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=ff6aff13a8cfc421418b902647ac84bf027bedb9'/>
<id>urn:sha1:ff6aff13a8cfc421418b902647ac84bf027bedb9</id>
<content type='text'>
commit e5a15e17a78d58f933d17cafedfcf7486a29f5b4 upstream.

The following kernel panic was captured when running nfs server over
ocfs2, at that time ocfs2_test_inode_bit() was checking whether one
inode locating at "blkno" 5 was valid, that is ocfs2 root inode, its
"suballoc_slot" was OCFS2_INVALID_SLOT(65535) and it was allocted from
//global_inode_alloc, but here it wrongly assumed that it was got from per
slot inode alloctor which would cause array overflow and trigger kernel
panic.

  BUG: unable to handle kernel paging request at 0000000000001088
  IP: [&lt;ffffffff816f6898&gt;] _raw_spin_lock+0x18/0xf0
  PGD 1e06ba067 PUD 1e9e7d067 PMD 0
  Oops: 0002 [#1] SMP
  CPU: 6 PID: 24873 Comm: nfsd Not tainted 4.1.12-124.36.1.el6uek.x86_64 #2
  Hardware name: Huawei CH121 V3/IT11SGCA1, BIOS 3.87 02/02/2018
  RIP: _raw_spin_lock+0x18/0xf0
  RSP: e02b:ffff88005ae97908  EFLAGS: 00010206
  RAX: ffff88005ae98000 RBX: 0000000000001088 RCX: 0000000000000000
  RDX: 0000000000020000 RSI: 0000000000000009 RDI: 0000000000001088
  RBP: ffff88005ae97928 R08: 0000000000000000 R09: ffff880212878e00
  R10: 0000000000007ff0 R11: 0000000000000000 R12: 0000000000001088
  R13: ffff8800063c0aa8 R14: ffff8800650c27d0 R15: 000000000000ffff
  FS:  0000000000000000(0000) GS:ffff880218180000(0000) knlGS:ffff880218180000
  CS:  e033 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000001088 CR3: 00000002033d0000 CR4: 0000000000042660
  Call Trace:
    igrab+0x1e/0x60
    ocfs2_get_system_file_inode+0x63/0x3a0 [ocfs2]
    ocfs2_test_inode_bit+0x328/0xa00 [ocfs2]
    ocfs2_get_parent+0xba/0x3e0 [ocfs2]
    reconnect_path+0xb5/0x300
    exportfs_decode_fh+0xf6/0x2b0
    fh_verify+0x350/0x660 [nfsd]
    nfsd4_putfh+0x4d/0x60 [nfsd]
    nfsd4_proc_compound+0x3d3/0x6f0 [nfsd]
    nfsd_dispatch+0xe0/0x290 [nfsd]
    svc_process_common+0x412/0x6a0 [sunrpc]
    svc_process+0x123/0x210 [sunrpc]
    nfsd+0xff/0x170 [nfsd]
    kthread+0xcb/0xf0
    ret_from_fork+0x61/0x90
  Code: 83 c2 02 0f b7 f2 e8 18 dc 91 ff 66 90 eb bf 0f 1f 40 00 55 48 89 e5 41 56 41 55 41 54 53 0f 1f 44 00 00 48 89 fb ba 00 00 02 00 &lt;f0&gt; 0f c1 17 89 d0 45 31 e4 45 31 ed c1 e8 10 66 39 d0 41 89 c6
  RIP   _raw_spin_lock+0x18/0xf0
  CR2: 0000000000001088
  ---[ end trace 7264463cd1aac8f9 ]---
  Kernel panic - not syncing: Fatal exception

Link: http://lkml.kernel.org/r/20200616183829.87211-4-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Reviewed-by: Joseph Qi &lt;joseph.qi@linux.alibaba.com&gt;
Cc: Changwei Ge &lt;gechangwei@live.cn&gt;
Cc: Gang He &lt;ghe@suse.com&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&gt;
Cc: Jun Piao &lt;piaojun@huawei.com&gt;
Cc: Mark Fasheh &lt;mark@fasheh.com&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;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ocfs2: fix value of OCFS2_INVALID_SLOT</title>
<updated>2020-06-30T19:37:09+00:00</updated>
<author>
<name>Junxiao Bi</name>
<email>junxiao.bi@oracle.com</email>
</author>
<published>2020-06-26T03:29:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=a8d82ebaee9747302d6ec9cbed0ced84943ebacc'/>
<id>urn:sha1:a8d82ebaee9747302d6ec9cbed0ced84943ebacc</id>
<content type='text'>
commit 9277f8334ffc719fe922d776444d6e4e884dbf30 upstream.

In the ocfs2 disk layout, slot number is 16 bits, but in ocfs2
implementation, slot number is 32 bits.  Usually this will not cause any
issue, because slot number is converted from u16 to u32, but
OCFS2_INVALID_SLOT was defined as -1, when an invalid slot number from
disk was obtained, its value was (u16)-1, and it was converted to u32.
Then the following checking in get_local_system_inode will be always
skipped:

 static struct inode **get_local_system_inode(struct ocfs2_super *osb,
                                               int type,
                                               u32 slot)
 {
 	BUG_ON(slot == OCFS2_INVALID_SLOT);
	...
 }

Link: http://lkml.kernel.org/r/20200616183829.87211-5-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Reviewed-by: Joseph Qi &lt;joseph.qi@linux.alibaba.com&gt;
Cc: Mark Fasheh &lt;mark@fasheh.com&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&gt;
Cc: Changwei Ge &lt;gechangwei@live.cn&gt;
Cc: Gang He &lt;ghe@suse.com&gt;
Cc: Jun Piao &lt;piaojun@huawei.com&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;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ocfs2: load global_inode_alloc</title>
<updated>2020-06-30T19:37:09+00:00</updated>
<author>
<name>Junxiao Bi</name>
<email>junxiao.bi@oracle.com</email>
</author>
<published>2020-06-26T03:29:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4685df862c8b8fcc16d754f3135e2c7ee4baf5de'/>
<id>urn:sha1:4685df862c8b8fcc16d754f3135e2c7ee4baf5de</id>
<content type='text'>
commit 7569d3c754e452769a5747eeeba488179e38a5da upstream.

Set global_inode_alloc as OCFS2_FIRST_ONLINE_SYSTEM_INODE, that will
make it load during mount.  It can be used to test whether some
global/system inodes are valid.  One use case is that nfsd will test
whether root inode is valid.

Link: http://lkml.kernel.org/r/20200616183829.87211-3-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Reviewed-by: Joseph Qi &lt;joseph.qi@linux.alibaba.com&gt;
Cc: Changwei Ge &lt;gechangwei@live.cn&gt;
Cc: Gang He &lt;ghe@suse.com&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&gt;
Cc: Jun Piao &lt;piaojun@huawei.com&gt;
Cc: Mark Fasheh &lt;mark@fasheh.com&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;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ocfs2: avoid inode removal while nfsd is accessing it</title>
<updated>2020-06-30T19:37:09+00:00</updated>
<author>
<name>Junxiao Bi</name>
<email>junxiao.bi@oracle.com</email>
</author>
<published>2020-06-26T03:29:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=7fa716a594a6ec6830222260f6502b25f3f86ed5'/>
<id>urn:sha1:7fa716a594a6ec6830222260f6502b25f3f86ed5</id>
<content type='text'>
commit 4cd9973f9ff69e37dd0ba2bd6e6423f8179c329a upstream.

Patch series "ocfs2: fix nfsd over ocfs2 issues", v2.

This is a series of patches to fix issues on nfsd over ocfs2.  patch 1
is to avoid inode removed while nfsd access it patch 2 &amp; 3 is to fix a
panic issue.

This patch (of 4):

When nfsd is getting file dentry using handle or parent dentry of some
dentry, one cluster lock is used to avoid inode removed from other node,
but it still could be removed from local node, so use a rw lock to avoid
this.

Link: http://lkml.kernel.org/r/20200616183829.87211-1-junxiao.bi@oracle.com
Link: http://lkml.kernel.org/r/20200616183829.87211-2-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Reviewed-by: Joseph Qi &lt;joseph.qi@linux.alibaba.com&gt;
Cc: Changwei Ge &lt;gechangwei@live.cn&gt;
Cc: Gang He &lt;ghe@suse.com&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&gt;
Cc: Jun Piao &lt;piaojun@huawei.com&gt;
Cc: Mark Fasheh &lt;mark@fasheh.com&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;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>btrfs: fix failure of RWF_NOWAIT write into prealloc extent beyond eof</title>
<updated>2020-06-30T19:37:08+00:00</updated>
<author>
<name>Filipe Manana</name>
<email>fdmanana@suse.com</email>
</author>
<published>2020-06-15T17:48:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=a79c3a99ac8187d79ce7cc6be8329454d2321ef5'/>
<id>urn:sha1:a79c3a99ac8187d79ce7cc6be8329454d2321ef5</id>
<content type='text'>
commit 4b1946284dd6641afdb9457101056d9e6ee6204c upstream.

If we attempt to write to prealloc extent located after eof using a
RWF_NOWAIT write, we always fail with -EAGAIN.

We do actually check if we have an allocated extent for the write at
the start of btrfs_file_write_iter() through a call to check_can_nocow(),
but later when we go into the actual direct IO write path we simply
return -EAGAIN if the write starts at or beyond EOF.

Trivial to reproduce:

  $ mkfs.btrfs -f /dev/sdb
  $ mount /dev/sdb /mnt

  $ touch /mnt/foo
  $ chattr +C /mnt/foo

  $ xfs_io -d -c "pwrite -S 0xab 0 64K" /mnt/foo
  wrote 65536/65536 bytes at offset 0
  64 KiB, 16 ops; 0.0004 sec (135.575 MiB/sec and 34707.1584 ops/sec)

  $ xfs_io -c "falloc -k 64K 1M" /mnt/foo

  $ xfs_io -d -c "pwrite -N -V 1 -S 0xfe -b 64K 64K 64K" /mnt/foo
  pwrite: Resource temporarily unavailable

On xfs and ext4 the write succeeds, as expected.

Fix this by removing the wrong check at btrfs_direct_IO().

Fixes: edf064e7c6fec3 ("btrfs: nowait aio support")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana &lt;fdmanana@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>
</entry>
<entry>
<title>btrfs: check if a log root exists before locking the log_mutex on unlink</title>
<updated>2020-06-30T19:37:08+00:00</updated>
<author>
<name>Filipe Manana</name>
<email>fdmanana@suse.com</email>
</author>
<published>2020-06-15T09:38:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=863a197f7f102bfbd42f79b40c50947e9019f011'/>
<id>urn:sha1:863a197f7f102bfbd42f79b40c50947e9019f011</id>
<content type='text'>
commit e7a79811d0db136dc2d336b56d54cf1b774ce972 upstream.

This brings back an optimization that commit e678934cbe5f02 ("btrfs:
Remove unnecessary check from join_running_log_trans") removed, but in
a different form. So it's almost equivalent to a revert.

That commit removed an optimization where we avoid locking a root's
log_mutex when there is no log tree created in the current transaction.
The affected code path is triggered through unlink operations.

That commit was based on the assumption that the optimization was not
necessary because we used to have the following checks when the patch
was authored:

  int btrfs_del_dir_entries_in_log(...)
  {
        (...)
        if (dir-&gt;logged_trans &lt; trans-&gt;transid)
            return 0;

        ret = join_running_log_trans(root);
        (...)
   }

   int btrfs_del_inode_ref_in_log(...)
   {
        (...)
        if (inode-&gt;logged_trans &lt; trans-&gt;transid)
            return 0;

        ret = join_running_log_trans(root);
        (...)
   }

However before that patch was merged, another patch was merged first which
replaced those checks because they were buggy.

That other patch corresponds to commit 803f0f64d17769 ("Btrfs: fix fsync
not persisting dentry deletions due to inode evictions"). The assumption
that if the logged_trans field of an inode had a smaller value then the
current transaction's generation (transid) meant that the inode was not
logged in the current transaction was only correct if the inode was not
evicted and reloaded in the current transaction. So the corresponding bug
fix changed those checks and replaced them with the following helper
function:

  static bool inode_logged(struct btrfs_trans_handle *trans,
                           struct btrfs_inode *inode)
  {
        if (inode-&gt;logged_trans == trans-&gt;transid)
                return true;

        if (inode-&gt;last_trans == trans-&gt;transid &amp;&amp;
            test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &amp;inode-&gt;runtime_flags) &amp;&amp;
            !test_bit(BTRFS_FS_LOG_RECOVERING, &amp;trans-&gt;fs_info-&gt;flags))
                return true;

        return false;
  }

So if we have a subvolume without a log tree in the current transaction
(because we had no fsyncs), every time we unlink an inode we can end up
trying to lock the log_mutex of the root through join_running_log_trans()
twice, once for the inode being unlinked (by btrfs_del_inode_ref_in_log())
and once for the parent directory (with btrfs_del_dir_entries_in_log()).

This means if we have several unlink operations happening in parallel for
inodes in the same subvolume, and the those inodes and/or their parent
inode were changed in the current transaction, we end up having a lot of
contention on the log_mutex.

The test robots from intel reported a -30.7% performance regression for
a REAIM test after commit e678934cbe5f02 ("btrfs: Remove unnecessary check
from join_running_log_trans").

So just bring back the optimization to join_running_log_trans() where we
check first if a log root exists before trying to lock the log_mutex. This
is done by checking for a bit that is set on the root when a log tree is
created and removed when a log tree is freed (at transaction commit time).

Commit e678934cbe5f02 ("btrfs: Remove unnecessary check from
join_running_log_trans") was merged in the 5.4 merge window while commit
803f0f64d17769 ("Btrfs: fix fsync not persisting dentry deletions due to
inode evictions") was merged in the 5.3 merge window. But the first
commit was actually authored before the second commit (May 23 2019 vs
June 19 2019).

Reported-by: kernel test robot &lt;rong.a.chen@intel.com&gt;
Link: https://lore.kernel.org/lkml/20200611090233.GL12456@shao2-debian/
Fixes: e678934cbe5f02 ("btrfs: Remove unnecessary check from join_running_log_trans")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik &lt;josef@toxicpanda.com&gt;
Signed-off-by: Filipe Manana &lt;fdmanana@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>
</entry>
<entry>
<title>btrfs: fix data block group relocation failure due to concurrent scrub</title>
<updated>2020-06-30T19:37:08+00:00</updated>
<author>
<name>Filipe Manana</name>
<email>fdmanana@suse.com</email>
</author>
<published>2020-06-08T12:32:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=53a0816610478ef21f72fa3898c96930203255b6'/>
<id>urn:sha1:53a0816610478ef21f72fa3898c96930203255b6</id>
<content type='text'>
commit 432cd2a10f1c10cead91fe706ff5dc52f06d642a upstream.

When running relocation of a data block group while scrub is running in
parallel, it is possible that the relocation will fail and abort the
current transaction with an -EINVAL error:

   [134243.988595] BTRFS info (device sdc): found 14 extents, stage: move data extents
   [134243.999871] ------------[ cut here ]------------
   [134244.000741] BTRFS: Transaction aborted (error -22)
   [134244.001692] WARNING: CPU: 0 PID: 26954 at fs/btrfs/ctree.c:1071 __btrfs_cow_block+0x6a7/0x790 [btrfs]
   [134244.003380] Modules linked in: btrfs blake2b_generic xor raid6_pq (...)
   [134244.012577] CPU: 0 PID: 26954 Comm: btrfs Tainted: G        W         5.6.0-rc7-btrfs-next-58 #5
   [134244.014162] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
   [134244.016184] RIP: 0010:__btrfs_cow_block+0x6a7/0x790 [btrfs]
   [134244.017151] Code: 48 c7 c7 (...)
   [134244.020549] RSP: 0018:ffffa41607863888 EFLAGS: 00010286
   [134244.021515] RAX: 0000000000000000 RBX: ffff9614bdfe09c8 RCX: 0000000000000000
   [134244.022822] RDX: 0000000000000001 RSI: ffffffffb3d63980 RDI: 0000000000000001
   [134244.024124] RBP: ffff961589e8c000 R08: 0000000000000000 R09: 0000000000000001
   [134244.025424] R10: ffffffffc0ae5955 R11: 0000000000000000 R12: ffff9614bd530d08
   [134244.026725] R13: ffff9614ced41b88 R14: ffff9614bdfe2a48 R15: 0000000000000000
   [134244.028024] FS:  00007f29b63c08c0(0000) GS:ffff9615ba600000(0000) knlGS:0000000000000000
   [134244.029491] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   [134244.030560] CR2: 00007f4eb339b000 CR3: 0000000130d6e006 CR4: 00000000003606f0
   [134244.031997] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   [134244.033153] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   [134244.034484] Call Trace:
   [134244.034984]  btrfs_cow_block+0x12b/0x2b0 [btrfs]
   [134244.035859]  do_relocation+0x30b/0x790 [btrfs]
   [134244.036681]  ? do_raw_spin_unlock+0x49/0xc0
   [134244.037460]  ? _raw_spin_unlock+0x29/0x40
   [134244.038235]  relocate_tree_blocks+0x37b/0x730 [btrfs]
   [134244.039245]  relocate_block_group+0x388/0x770 [btrfs]
   [134244.040228]  btrfs_relocate_block_group+0x161/0x2e0 [btrfs]
   [134244.041323]  btrfs_relocate_chunk+0x36/0x110 [btrfs]
   [134244.041345]  btrfs_balance+0xc06/0x1860 [btrfs]
   [134244.043382]  ? btrfs_ioctl_balance+0x27c/0x310 [btrfs]
   [134244.045586]  btrfs_ioctl_balance+0x1ed/0x310 [btrfs]
   [134244.045611]  btrfs_ioctl+0x1880/0x3760 [btrfs]
   [134244.049043]  ? do_raw_spin_unlock+0x49/0xc0
   [134244.049838]  ? _raw_spin_unlock+0x29/0x40
   [134244.050587]  ? __handle_mm_fault+0x11b3/0x14b0
   [134244.051417]  ? ksys_ioctl+0x92/0xb0
   [134244.052070]  ksys_ioctl+0x92/0xb0
   [134244.052701]  ? trace_hardirqs_off_thunk+0x1a/0x1c
   [134244.053511]  __x64_sys_ioctl+0x16/0x20
   [134244.054206]  do_syscall_64+0x5c/0x280
   [134244.054891]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
   [134244.055819] RIP: 0033:0x7f29b51c9dd7
   [134244.056491] Code: 00 00 00 (...)
   [134244.059767] RSP: 002b:00007ffcccc1dd08 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
   [134244.061168] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f29b51c9dd7
   [134244.062474] RDX: 00007ffcccc1dda0 RSI: 00000000c4009420 RDI: 0000000000000003
   [134244.063771] RBP: 0000000000000003 R08: 00005565cea4b000 R09: 0000000000000000
   [134244.065032] R10: 0000000000000541 R11: 0000000000000202 R12: 00007ffcccc2060a
   [134244.066327] R13: 00007ffcccc1dda0 R14: 0000000000000002 R15: 00007ffcccc1dec0
   [134244.067626] irq event stamp: 0
   [134244.068202] hardirqs last  enabled at (0): [&lt;0000000000000000&gt;] 0x0
   [134244.069351] hardirqs last disabled at (0): [&lt;ffffffffb2abdedf&gt;] copy_process+0x74f/0x2020
   [134244.070909] softirqs last  enabled at (0): [&lt;ffffffffb2abdedf&gt;] copy_process+0x74f/0x2020
   [134244.072392] softirqs last disabled at (0): [&lt;0000000000000000&gt;] 0x0
   [134244.073432] ---[ end trace bd7c03622e0b0a99 ]---

The -EINVAL error comes from the following chain of function calls:

  __btrfs_cow_block() &lt;-- aborts the transaction
    btrfs_reloc_cow_block()
      replace_file_extents()
        get_new_location() &lt;-- returns -EINVAL

When relocating a data block group, for each allocated extent of the block
group, we preallocate another extent (at prealloc_file_extent_cluster()),
associated with the data relocation inode, and then dirty all its pages.
These preallocated extents have, and must have, the same size that extents
from the data block group being relocated have.

Later before we start the relocation stage that updates pointers (bytenr
field of file extent items) to point to the the new extents, we trigger
writeback for the data relocation inode. The expectation is that writeback
will write the pages to the previously preallocated extents, that it
follows the NOCOW path. That is generally the case, however, if a scrub
is running it may have turned the block group that contains those extents
into RO mode, in which case writeback falls back to the COW path.

However in the COW path instead of allocating exactly one extent with the
expected size, the allocator may end up allocating several smaller extents
due to free space fragmentation - because we tell it at cow_file_range()
that the minimum allocation size can match the filesystem's sector size.
This later breaks the relocation's expectation that an extent associated
to a file extent item in the data relocation inode has the same size as
the respective extent pointed by a file extent item in another tree - in
this case the extent to which the relocation inode poins to is smaller,
causing relocation.c:get_new_location() to return -EINVAL.

For example, if we are relocating a data block group X that has a logical
address of X and the block group has an extent allocated at the logical
address X + 128KiB with a size of 64KiB:

1) At prealloc_file_extent_cluster() we allocate an extent for the data
   relocation inode with a size of 64KiB and associate it to the file
   offset 128KiB (X + 128KiB - X) of the data relocation inode. This
   preallocated extent was allocated at block group Z;

2) A scrub running in parallel turns block group Z into RO mode and
   starts scrubing its extents;

3) Relocation triggers writeback for the data relocation inode;

4) When running delalloc (btrfs_run_delalloc_range()), we try first the
   NOCOW path because the data relocation inode has BTRFS_INODE_PREALLOC
   set in its flags. However, because block group Z is in RO mode, the
   NOCOW path (run_delalloc_nocow()) falls back into the COW path, by
   calling cow_file_range();

5) At cow_file_range(), in the first iteration of the while loop we call
   btrfs_reserve_extent() to allocate a 64KiB extent and pass it a minimum
   allocation size of 4KiB (fs_info-&gt;sectorsize). Due to free space
   fragmentation, btrfs_reserve_extent() ends up allocating two extents
   of 32KiB each, each one on a different iteration of that while loop;

6) Writeback of the data relocation inode completes;

7) Relocation proceeds and ends up at relocation.c:replace_file_extents(),
   with a leaf which has a file extent item that points to the data extent
   from block group X, that has a logical address (bytenr) of X + 128KiB
   and a size of 64KiB. Then it calls get_new_location(), which does a
   lookup in the data relocation tree for a file extent item starting at
   offset 128KiB (X + 128KiB - X) and belonging to the data relocation
   inode. It finds a corresponding file extent item, however that item
   points to an extent that has a size of 32KiB, which doesn't match the
   expected size of 64KiB, resuling in -EINVAL being returned from this
   function and propagated up to __btrfs_cow_block(), which aborts the
   current transaction.

To fix this make sure that at cow_file_range() when we call the allocator
we pass it a minimum allocation size corresponding the desired extent size
if the inode belongs to the data relocation tree, otherwise pass it the
filesystem's sector size as the minimum allocation size.

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>
</entry>
</feed>
