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authorTheodore Ts'o <tytso@mit.edu>2012-10-10 01:06:58 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-11-26 12:14:31 -0800
commit19dfc178ae0ed43e3cc8407f7876497a3ee5ba95 (patch)
parent03faff7a2288f69b0a2218f1cd0e0d81e31e6509 (diff)
ext4: fix metadata checksum calculation for the superblock
commit 06db49e68ae70cf16819b85a14057acb2820776a upstream. 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> Tested-by: George Spelvin <linux@horizon.com>
4 files changed, 8 insertions, 12 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5c69f2b32b1c..b686b43164ae 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2046,8 +2046,7 @@ extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);
extern int ext4_calculate_overhead(struct super_block *sb);
extern int ext4_superblock_csum_verify(struct super_block *sb,
struct ext4_super_block *es);
-extern void ext4_superblock_csum_set(struct super_block *sb,
- struct ext4_super_block *es);
+extern void ext4_superblock_csum_set(struct super_block *sb);
extern void *ext4_kvmalloc(size_t size, gfp_t flags);
extern void *ext4_kvzalloc(size_t size, gfp_t flags);
extern void ext4_kvfree(void *ptr);
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
- }
return err;
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 71241bc0eea6..101b41c6844c 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -979,7 +979,7 @@ static void update_backups(struct super_block *sb,
goto exit_err;
- ext4_superblock_csum_set(sb, (struct ext4_super_block *)data);
+ ext4_superblock_csum_set(sb);
while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
struct buffer_head *bh;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e44b23362088..2b5fb603b2b6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -143,9 +143,10 @@ int ext4_superblock_csum_verify(struct super_block *sb,
return es->s_checksum == ext4_superblock_csum(sb, es);
-void ext4_superblock_csum_set(struct super_block *sb,
- struct ext4_super_block *es)
+void ext4_superblock_csum_set(struct super_block *sb)
+ struct ext4_super_block *es = EXT4_SB(sb)->s_es;
@@ -4343,7 +4344,7 @@ static int ext4_commit_super(struct super_block *sb, int sync)
BUFFER_TRACE(sbh, "marking dirty");
- ext4_superblock_csum_set(sb, es);
+ ext4_superblock_csum_set(sb);
if (sync) {
error = sync_dirty_buffer(sbh);