ext4: fix deadlock with quota feature

We didn't mark hidden quota files with S_NOQUOTA flag and thus quota was
accounted even for quota files. Thus we could recurse back to quota code
when adding new blocks to quota file which can easily deadlock. Mark
hidden quota files properly.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 525beb6e3e1e..968ca9369175 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4953,6 +4953,8 @@ static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
                 return PTR_ERR(qf_inode);
         }
 
+        /* Don't account quota for quota files to avoid recursion */
+        qf_inode->i_flags |= S_NOQUOTA;
         err = dquot_enable(qf_inode, type, format_id, flags);
         iput(qf_inode);