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authorTheodore Ts'o <tytso@mit.edu>2012-10-10 01:06:58 -0400
committerTheodore Ts'o <tytso@mit.edu>2012-10-10 01:06:58 -0400
commit06db49e68ae70cf16819b85a14057acb2820776a (patch)
tree4b9ac4222aef2c6605ffea5e0986b91be6e2c797 /fs/ext4/ext4_jbd2.c
parentdee1f973ca341c266229faa5a1a5bb268bed3531 (diff)
downloadlinux-linaro-stable-06db49e68ae70cf16819b85a14057acb2820776a.tar.gz
ext4: fix metadata checksum calculation for the superblock
The function ext4_handle_dirty_super() was calculating the superblock on the wrong block data. As a result, when the superblock is modified while it is mounted (most commonly, when inodes are added or removed from the orphan list), the superblock checksum would be wrong. We didn't notice because the superblock *was* being correctly calculated in ext4_commit_super(), and this would get called when the file system was unmounted. So the problem only became obvious if the system crashed while the file system was mounted. Fix this by removing the poorly designed function signature for ext4_superblock_csum_set(); if it only took a single argument, the pointer to a struct superblock, the ambiguity which caused this mistake would have been impossible. Reported-by: George Spelvin <linux@horizon.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/ext4_jbd2.c')
-rw-r--r--fs/ext4/ext4_jbd2.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index bfa65b49d424..b4323ba846b5 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -143,17 +143,13 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line,
struct buffer_head *bh = EXT4_SB(sb)->s_sbh;
int err = 0;
+ ext4_superblock_csum_set(sb);
if (ext4_handle_valid(handle)) {
- ext4_superblock_csum_set(sb,
- (struct ext4_super_block *)bh->b_data);
err = jbd2_journal_dirty_metadata(handle, bh);
if (err)
ext4_journal_abort_handle(where, line, __func__,
bh, handle, err);
- } else {
- ext4_superblock_csum_set(sb,
- (struct ext4_super_block *)bh->b_data);
+ } else
mark_buffer_dirty(bh);
- }
return err;
}