This is a note to let you know that I've just added the patch titled
ext4: Fix ext4_should_writeback_data() for no-journal mode
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-ext4_should_writeback_data-for-no-journal-mode.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 441c850857148935babe000fc2ba1455fe54a6a9 Mon Sep 17 00:00:00 2001
From: Curt Wohlgemuth <[email protected]>
Date: Sat, 13 Aug 2011 11:25:18 -0400
Subject: ext4: Fix ext4_should_writeback_data() for no-journal mode
From: Curt Wohlgemuth <[email protected]>
commit 441c850857148935babe000fc2ba1455fe54a6a9 upstream.
ext4_should_writeback_data() had an incorrect sequence of
tests to determine if it should return 0 or 1: in
particular, even in no-journal mode, 0 was being returned
for a non-regular-file inode.
This meant that, in non-journal mode, we would use
ext4_journalled_aops for directories, symlinks, and other
non-regular files. However, calling journalled aop
callbacks when there is no valid handle, can cause problems.
This would cause a kernel crash with Jan Kara's commit
2d859db3e4 ("ext4: fix data corruption in inodes with
journalled data"), because we now dereference 'handle' in
ext4_journalled_write_end().
I also added BUG_ONs to check for a valid handle in the
obviously journal-only aops callbacks.
I tested this running xfstests with a scratch device in
these modes:
- no-journal
- data=ordered
- data=writeback
- data=journal
All work fine; the data=journal run has many failures and a
crash in xfstests 074, but this is no different from a
vanilla kernel.
Signed-off-by: Curt Wohlgemuth <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/ext4/ext4_jbd2.h | 4 ++--
fs/ext4/inode.c | 4 ++++
2 files changed, 6 insertions(+), 2 deletions(-)
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -289,10 +289,10 @@ static inline int ext4_should_order_data
static inline int ext4_should_writeback_data(struct inode *inode)
{
- if (!S_ISREG(inode->i_mode))
- return 0;
if (EXT4_JOURNAL(inode) == NULL)
return 1;
+ if (!S_ISREG(inode->i_mode))
+ return 0;
if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
return 0;
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1849,6 +1849,8 @@ static int ext4_journalled_write_end(str
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + len;
+ BUG_ON(!ext4_handle_valid(handle));
+
if (copied < len) {
if (!PageUptodate(page))
copied = 0;
@@ -2564,6 +2566,8 @@ static int __ext4_journalled_writepage(s
goto out;
}
+ BUG_ON(!ext4_handle_valid(handle));
+
ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
do_journal_get_write_access);
Patches currently in stable-queue which might be from [email protected] are
queue-3.0/ext4-fix-ext4_should_writeback_data-for-no-journal-mode.patch
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