ext4: Fix deadlock with quota feature

Submitted by Jan Kara on April 5, 2013, 10:06 a.m.

Details

Message ID 1365156382-16703-1-git-send-email-jack@suse.cz
State Accepted, archived
Headers show

Commit Message

Jan Kara April 5, 2013, 10:06 a.m.
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>
---
 fs/ext4/super.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

Comments

Theodore Ts'o April 9, 2013, 1:20 p.m.
On Fri, Apr 05, 2013 at 12:06:22PM +0200, Jan Kara wrote:
> 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>

Thanks, applied.

					- Ted
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diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5d6d535..fc203b3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4945,6 +4945,8 @@  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);