From: Hugh Dickins <hughd@google.com>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: next/mmotm: ext4 causes !rwsem_is_locked warnings
Date: Thu, 27 Sep 2012 14:05:00 -0700 (PDT) [thread overview]
Message-ID: <alpine.LSU.2.00.1209271334560.2226@eggly.anvils> (raw)
Hi Ted,
mmotm (or next) now gives me lots of WARNING at fs/fs-writeback.c:1312 from
writeback_inodes_sb_nr(). That's WARN_ON(!rwsem_is_locked(&sb->s_umount))
(some useful safety from hch) in writeback_inodes_sb_nr().
Your commit 40e684e5c597a98996cf4616e31fb2581ec82060
"ext4: fix potential deadlock in ext4_nonda_switch()" needs more change
to fs/fs-writeback.c. I guess I'm the only one using a nearly full ext4.
I am, of course, applying the patch at the bottom to my tree for now;
but I think you'd do better not to eliminate that check. Maybe add a
special wb_reason for your case, and skip rwsem check in that case.
Hugh
WARNING: at fs/fs-writeback.c:1312 writeback_inodes_sb_nr+0x6e/0xca()
Hardware name: GU658AA-ABU a6250.uk
ACPI: Invalid Power Resource to register!
Modules linked in: snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device
Pid: 20839, comm: objcopy Not tainted 3.6.0-rc7-mm1 #1
Call Trace:
[<ffffffff8102f7b7>] warn_slowpath_common+0x80/0x98
[<ffffffff8102f7e4>] warn_slowpath_null+0x15/0x17
[<ffffffff810f55a8>] writeback_inodes_sb_nr+0x6e/0xca
[<ffffffff810f58a1>] writeback_inodes_sb+0x22/0x29
[<ffffffff81131b2a>] ext4_nonda_switch+0x8b/0x93
[<ffffffff81134cda>] ext4_da_write_begin+0x48/0x180
[<ffffffff8108718d>] generic_perform_write+0xc0/0x1e0
[<ffffffff81087300>] generic_file_buffered_write+0x53/0x7d
[<ffffffff81088c64>] __generic_file_aio_write+0x2a5/0x2d5
[<ffffffff81088d05>] generic_file_aio_write+0x71/0xda
[<ffffffff8112f203>] ext4_file_write+0xb0/0xb7
[<ffffffff810d6f0a>] do_sync_write+0x98/0xd5
[<ffffffff810d75d2>] vfs_write+0xb0/0x12c
[<ffffffff810d783f>] sys_write+0x4f/0x79
[<ffffffff813b6732>] system_call_fastpath+0x16/0x1b
---
fs/fs-writeback.c | 1 -
1 file changed, 1 deletion(-)
--- mmotm/fs/fs-writeback.c 2012-09-26 10:15:29.368071559 -0700
+++ linux/fs/fs-writeback.c 2012-09-26 22:38:25.648719969 -0700
@@ -1309,7 +1309,6 @@ void writeback_inodes_sb_nr(struct super
if (sb->s_bdi == &noop_backing_dev_info)
return;
- WARN_ON(!rwsem_is_locked(&sb->s_umount));
bdi_queue_work(sb->s_bdi, &work);
wait_for_completion(&done);
}
next reply other threads:[~2012-09-27 21:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 21:05 Hugh Dickins [this message]
2012-09-27 21:27 ` next/mmotm: ext4 causes !rwsem_is_locked warnings Theodore Ts'o
2012-09-28 3:31 ` [PATCH v2] ext4: fix potential deadlock in ext4_nonda_switch() Theodore Ts'o
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