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    btrfs: fix crash when trying to resume balance without the resume flag · 02ee654d
    Anand Jain 提交于
    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: NAnand Jain <anand.jain@oracle.com>
    Reviewed-by: NDavid Sterba <dsterba@suse.com>
    Signed-off-by: NDavid Sterba <dsterba@suse.com>
    02ee654d
volumes.c 194.4 KB