2008-12-02 11:22:42

by Toshiyuki Okajima

[permalink] [raw]
Subject: [BUG][PATCH 2/4] ext4: fix a cause of __schedule_bug via blkdev_releasepage

ext4: fix a cause of __schedule_bug via blkdev_releasepage
From: Toshiyuki Okajima <[email protected]>

A cause of this problem is calling jbd2_log_wait_commit() on
jbd2_journal_try_to_free_buffers() with a read-lock via blkdev_releasepage().
This logic is for uncommitted data buffers. And a read/write-lock is required
for a client usage of blkdev_releasepage.

By the way, we want to release only metadata buffers on ext4_release_metadata().
Because a page which binds to blkdev is used as metadata for ext4.

Therefore we don't need to wait for a commit on
jbd2_journal_try_to_free_buffers() via ext4_release_matadata().
As a result, we add a jbd2_journal_try_to_free_metadata_buffers() almost same
as jbd2_journal_try_to_free_buffers() except not calling jbd2_log_wait_commit().
So, we change jbd2_journal_try_to_free_buffers() with

This issue was reported by Aneesh Kumar K.V.

Reported-by: "Aneesh Kumar K.V" <[email protected]>
Signed-off-by: Toshiyuki Okajima <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
fs/ext4/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff -Nurp linux-2.6.28-rc6/fs/ext4/inode.c linux-2.6.28-rc6.2/fs/ext4/inode.c
--- linux-2.6.28-rc6/fs/ext4/inode.c 2008-12-02 09:32:27.000000000 +0900
+++ linux-2.6.28-rc6.2/fs/ext4/inode.c 2008-12-02 09:52:46.000000000 +0900
@@ -3018,7 +3018,7 @@ int ext4_release_metadata(void *client,
BUG_ON(EXT4_SB(sb) == NULL);
journal = EXT4_SB(sb)->s_journal;
if (journal != NULL)
- return jbd2_journal_try_to_free_buffers(journal, page, wait);
+ return jbd2_journal_try_to_free_metadata_buffers(journal, page, wait);
return try_to_free_buffers(page);