xfs: release dquot buffer after dqflush failure

xfs: release dquot buffer after dqflush failure

xfs_qm_dqpurge() gets a locked buffer from xfs_dquot_use_attached_buf().
If xfs_qm_dqflush() fails, the error path skips xfs_buf_relse() and then
calls xfs_dquot_detach_buf(), which tries to lock the same buffer again.

Release the buffer after xfs_qm_dqflush() returns so the error path drops
the caller hold and unlocks the buffer before the dquot is detached,
matching the other dqflush callers.

Fixes: a40fe30868ba ("xfs: separate dquot buffer reads from xfs_dqflush")
Cc: stable@vger.kernel.org # v6.13+
Signed-off-by: Yingjie Gao <gaoyingjie@uniontech.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>