Jan Kara 34cf865d54 ext4: fix deadlock when writing in ENOSPC conditions
Akira-san has been reporting rare deadlocks of his machine when running
xfstests test 269 on ext4 filesystem. The problem turned out to be in
ext4_da_reserve_metadata() and ext4_da_reserve_space() which called
ext4_should_retry_alloc() while holding i_data_sem. Since
ext4_should_retry_alloc() can force a transaction commit, this is a
lock ordering violation and leads to deadlocks.

Fix the problem by just removing the retry loops. These functions should
just report ENOSPC to the caller (e.g. ext4_da_write_begin()) and that
function must take care of retrying after dropping all necessary locks.

Reported-and-tested-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2013-12-18 00:44:44 -05:00
..
2013-10-24 23:43:27 -04:00
2013-11-13 12:09:12 +09:00
2013-06-29 12:56:53 +04:00
2013-12-08 21:14:59 -05:00
2013-10-27 16:27:07 -07:00
2013-09-16 18:20:25 -07:00
2013-11-16 13:14:56 -08:00
2013-11-09 00:16:32 -05:00
2013-06-29 12:56:39 +04:00
2013-11-22 08:37:47 -08:00
2013-11-22 08:42:14 -08:00
2013-06-29 12:57:04 +04:00
2013-10-24 23:34:54 -04:00
2013-09-13 23:06:40 -04:00
2013-10-24 23:34:54 -04:00
2013-06-29 12:57:05 +04:00
2013-09-10 18:56:31 -04:00
2013-10-24 23:34:54 -04:00
2013-11-09 00:16:20 -05:00
2013-10-24 23:34:54 -04:00
2013-11-09 00:16:19 -05:00
2013-11-09 00:16:19 -05:00
2013-10-24 23:35:00 -04:00
2013-10-24 23:34:54 -04:00
2013-10-24 23:34:54 -04:00
2013-10-24 23:34:54 -04:00
2013-11-09 00:16:31 -05:00
2013-11-09 00:16:20 -05:00