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    btrfs: resume qgroup rescan on rw remount · 6c6b5a39
    Aleksa Sarai 提交于
    Several distributions mount the "proper root" as ro during initrd and
    then remount it as rw before pivot_root(2). Thus, if a rescan had been
    aborted by a previous shutdown, the rescan would never be resumed.
    
    This issue would manifest itself as several btrfs ioctl(2)s causing the
    entire machine to hang when btrfs_qgroup_wait_for_completion was hit
    (due to the fs_info->qgroup_rescan_running flag being set but the rescan
    itself not being resumed). Notably, Docker's btrfs storage driver makes
    regular use of BTRFS_QUOTA_CTL_DISABLE and BTRFS_IOC_QUOTA_RESCAN_WAIT
    (causing this problem to be manifested on boot for some machines).
    
    Cc: <stable@vger.kernel.org> # v3.11+
    Cc: Jeff Mahoney <jeffm@suse.com>
    Fixes: b382a324 ("Btrfs: fix qgroup rescan resume on mount")
    Signed-off-by: NAleksa Sarai <asarai@suse.de>
    Reviewed-by: NNikolay Borisov <nborisov@suse.com>
    Tested-by: NNikolay Borisov <nborisov@suse.com>
    Signed-off-by: NDavid Sterba <dsterba@suse.com>
    6c6b5a39
super.c 63.3 KB