The patch titled
circular locking dependency found in QUOTA OFF
has been added to the -mm tree. Its filename is
circular-locking-dependency-found-in-quota-off.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: circular locking dependency found in QUOTA OFF
From: Jan Kara <jack@xxxxxxx>
i_mutex on quota files is special. Unlike i_mutexes for other inodes it is
acquired under dqonoff_mutex. Tell lockdep about this lock ranking. Also
comment and code in quota_sync_sb() seem to be bogus (as i_mutex for quota
file can be acquired under dqonoff_mutex). Move truncate_inode_pages()
call under dqonoff_mutex and save some problems with races...
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/dquot.c | 2 +-
fs/quota.c | 23 +++++++----------------
2 files changed, 8 insertions(+), 17 deletions(-)
diff -puN fs/dquot.c~circular-locking-dependency-found-in-quota-off fs/dquot.c
--- a/fs/dquot.c~circular-locking-dependency-found-in-quota-off
+++ a/fs/dquot.c
@@ -1421,7 +1421,7 @@ int vfs_quota_off(struct super_block *sb
/* If quota was reenabled in the meantime, we have
* nothing to do */
if (!sb_has_quota_enabled(sb, cnt)) {
- mutex_lock(&toputinode[cnt]->i_mutex);
+ mutex_lock_nested(&toputinode[cnt]->i_mutex, I_MUTEX_QUOTA);
toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
S_NOATIME | S_NOQUOTA);
truncate_inode_pages(&toputinode[cnt]->i_data, 0);
diff -puN fs/quota.c~circular-locking-dependency-found-in-quota-off fs/quota.c
--- a/fs/quota.c~circular-locking-dependency-found-in-quota-off
+++ a/fs/quota.c
@@ -157,7 +157,6 @@ static int check_quotactl_valid(struct s
static void quota_sync_sb(struct super_block *sb, int type)
{
int cnt;
- struct inode *discard[MAXQUOTAS];
sb->s_qcop->quota_sync(sb, type);
/* This is not very clever (and fast) but currently I don't know about
@@ -167,29 +166,21 @@ static void quota_sync_sb(struct super_b
sb->s_op->sync_fs(sb, 1);
sync_blockdev(sb->s_bdev);
- /* Now when everything is written we can discard the pagecache so
- * that userspace sees the changes. We need i_mutex and so we could
- * not do it inside dqonoff_mutex. Moreover we need to be carefull
- * about races with quotaoff() (that is the reason why we have own
- * reference to inode). */
+ /*
+ * Now when everything is written we can discard the pagecache so
+ * that userspace sees the changes.
+ */
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
- discard[cnt] = NULL;
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_enabled(sb, cnt))
continue;
- discard[cnt] = igrab(sb_dqopt(sb)->files[cnt]);
+ mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA);
+ truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
+ mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
}
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
- for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
- if (discard[cnt]) {
- mutex_lock(&discard[cnt]->i_mutex);
- truncate_inode_pages(&discard[cnt]->i_data, 0);
- mutex_unlock(&discard[cnt]->i_mutex);
- iput(discard[cnt]);
- }
- }
}
void sync_dquots(struct super_block *sb, int type)
_
Patches currently in -mm which might be from jack@xxxxxxx are
circular-locking-dependency-found-in-quota-off.patch
ext4-copy-i_flags-to-inode-flags-on-write.patch
-
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