On Tuesday 30 June 2020 9:11:56 PM IST Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> In commit 8d3d7e2b35ea, we changed xfs_qm_dqpurge to bail out if we
> can't lock the dquot buf to flush the dquot. This prevents the AIL from
> blocking on the dquot, but it also forgets to clear the FREEING flag on
> its way out. A subsequent purge attempt will see the FREEING flag is
> set and bail out, which leads to dqpurge_all failing to purge all the
> dquots. This causes unmounts and quotaoff operations to hang.
>
xfs_qm_dqpurge() checks for the presence of XFS_DQ_FREEING. If it is set, it
indicates that another task is freeing this dquot.
A failed read operation could return -EAGAIN and hence xfs_qm_dqpurge()
returning without clearing XFS_DQ_FREEING would mean that future invocations
of this function would turn out to be a nop and hence the corresponding dquot
would linger around forever. Hence the fix is correct.
Reviewed-by: Chandan Babu R <chandanrlinux@xxxxxxxxx>
> Fixes: 8d3d7e2b35ea ("xfs: trylock underlying buffer on dquot flush")
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/xfs_qm.c | 1 +
> 1 file changed, 1 insertion(+)
>
>
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index d6cd83317344..938023dd8ce5 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -148,6 +148,7 @@ xfs_qm_dqpurge(
> error = xfs_bwrite(bp);
> xfs_buf_relse(bp);
> } else if (error == -EAGAIN) {
> + dqp->dq_flags &= ~XFS_DQ_FREEING;
> goto out_unlock;
> }
> xfs_dqflock(dqp);
>
>
--
chandan
