From: Jan Kara jack@suse.cz
[ Upstream commit e0770e91424f694b461141cbc99adf6b23006b60 ]
When we try to use file already used as a quota file again (for the same or different quota type), strange things can happen. At the very least lockdep annotations may be wrong but also inode flags may be wrongly set / reset. When the file is used for two quota types at once we can even corrupt the file and likely crash the kernel. Catch all these cases by checking whether passed file is already used as quota file and bail early in that case.
This fixes occasional generic/219 failure due to lockdep complaint.
Reviewed-by: Andreas Dilger adilger@dilger.ca Reported-by: Ritesh Harjani riteshh@linux.ibm.com Signed-off-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20201015110330.28716-1-jack@suse.cz Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/super.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index aca086a25b2ef..6350971852e19 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5185,6 +5185,11 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id, /* Quotafile not on the same filesystem? */ if (path->dentry->d_sb != sb) return -EXDEV; + + /* Quota already enabled for this file? */ + if (IS_NOQUOTA(d_inode(path->dentry))) + return -EBUSY; + /* Journaling quota? */ if (EXT4_SB(sb)->s_qf_names[type]) { /* Quotafile not in fs root? */