linux-kernel - [PATCH 3.10 086/180] ext4: don't call ext4_should_journal

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Message-Id: <1471793510-13022-87-git-send-email-w@1wt.eu>
Date:   Sun, 21 Aug 2016 17:30:16 +0200
From:   Willy Tarreau <w@....eu>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Vegard Nossum <vegard.nossum@...cle.com>, Jan Kara <jack@...e.cz>,
        "Theodore Ts'o" <tytso@....edu>, Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 086/180] ext4: don't call ext4_should_journal_data() on the journal inode

From: Vegard Nossum <vegard.nossum@...cle.com>

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@...e.cz>
Cc: stable@...r.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@...cle.com>
Signed-off-by: Theodore Ts'o <tytso@....edu>
Reviewed-by: Jan Kara <jack@...e.cz>
Signed-off-by: Willy Tarreau <w@....eu>
---
 fs/ext4/inode.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fb7e576d..221b582 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -206,9 +206,9 @@ void ext4_evict_inode(struct inode *inode)
 		 * 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;
 
-- 
2.8.0.rc2.1.gbe9624a