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| author | Anand Jain <anand.jain@oracle.com> | 2018-05-17 15:16:51 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-05-17 14:38:24 +0200 |
| commit | 02ee654d3a04563c67bfe658a05384548b9bb105 (patch) | |
| tree | 28fd96d01ae0bca8ef64a8b588234ad1593ae36e /fs | |
| parent | fe816d0f1d4c31c4c31d42ca78a87660565fc800 (diff) | |
| download | linux-02ee654d3a04563c67bfe658a05384548b9bb105.tar.gz linux-02ee654d3a04563c67bfe658a05384548b9bb105.tar.bz2 linux-02ee654d3a04563c67bfe658a05384548b9bb105.zip | |
btrfs: fix crash when trying to resume balance without the resume flag
We set the BTRFS_BALANCE_RESUME flag in the btrfs_recover_balance()
only, which isn't called during the remount. So when resuming from
the paused balance we hit the bug:
kernel: kernel BUG at fs/btrfs/volumes.c:3890!
::
kernel: balance_kthread+0x51/0x60 [btrfs]
kernel: kthread+0x111/0x130
::
kernel: RIP: btrfs_balance+0x12e1/0x1570 [btrfs] RSP: ffffba7d0090bde8
Reproducer:
On a mounted filesystem:
btrfs balance start --full-balance /btrfs
btrfs balance pause /btrfs
mount -o remount,ro /dev/sdb /btrfs
mount -o remount,rw /dev/sdb /btrfs
To fix this set the BTRFS_BALANCE_RESUME flag in
btrfs_resume_balance_async().
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/volumes.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 292266f6ab9c..be3fc701f389 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4052,6 +4052,15 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info) return 0; } + /* + * A ro->rw remount sequence should continue with the paused balance + * regardless of who pauses it, system or the user as of now, so set + * the resume flag. + */ + spin_lock(&fs_info->balance_lock); + fs_info->balance_ctl->flags |= BTRFS_BALANCE_RESUME; + spin_unlock(&fs_info->balance_lock); + tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance"); return PTR_ERR_OR_ZERO(tsk); } |