We should return -EROFS rather than other errno if filesystem becomes
read-only.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/5B191B26.9010501@huawei.comSigned-off-by: NJun Piao <piaojun@huawei.com>
Reviewed-by: NYiwen Jiang <jiangyiwen@huawei.com>
Acked-by: NJoseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>