ext4: don't call ext4_should_journal_data() on the journal inode

commit 6a7fd522a7c94cdef0a3b08acf8e6702056e635c upstream.

If ext4_fill_super() fails early, it's possible for ext4_evict_inode()
to call ext4_should_journal_data() before superblock options and flags
are fully set up.  In that case, the iput() on the journal inode can
end up causing a BUG().

Work around this problem by reordering the tests so we only call
ext4_should_journal_data() after we know it's not the journal inode.

Fixes: 2d859db3e4 ("ext4: fix data corruption in inodes with journalled data")
Fixes: 2b405bfa84 ("ext4: fix data=journal fast mount/umount hang")
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 010f050..2b534b5 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -142,9 +142,9 @@ void ext4_evict_inode(struct inode *inode)
                 * Note that directories do not have this problem because they
                 * don't use page cache.
                 */
                 * Note that directories do not have this problem because they
                 * don't use page cache.
                 */

-               if (ext4_should_journal_data(inode) &&
-                   (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
-                   inode->i_ino != EXT4_JOURNAL_INO) {
+               if (inode->i_ino != EXT4_JOURNAL_INO &&
+                   ext4_should_journal_data(inode) &&
+                   (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {

                        journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
                        tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
 
                        journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
                        tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;