aboutsummaryrefslogtreecommitdiff
path: root/fs/quota
diff options
context:
space:
mode:
authorJan Kara <jack@suse.cz>2012-04-25 21:15:53 +0200
committerJan Kara <jack@suse.cz>2012-05-15 23:34:39 +0200
commita80b12c3d08dbbf15e6a551e481c32a2df4911f3 (patch)
tree364989f0fc990496820296b5fc6b655e29416c14 /fs/quota
parentf9ef178412cab442719c9ffdc659933f5f2fa87e (diff)
downloadlinaro-lsk-a80b12c3d08dbbf15e6a551e481c32a2df4911f3.tar.gz
quota: Get rid of nested I_MUTEX_QUOTA locking subclass
So far i_mutex was ranking above dqonoff_mutex and i_mutex on quota files was special and ranking below dqonoff_mutex (and several other locks). However there's no real need for i_mutex on quota files to be special. IO on quota files is serialized by dqio_mutex anyway so we don't need to take i_mutex when writing to quota files. Other places where we take i_mutex on quota file can accomodate standard i_mutex lock ranking, we only need to change the lock ranking to be dqonoff_mutex > i_mutex which is a matter of changing documentation because there's no place which would enforce ordering in the other direction. Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/quota')
-rw-r--r--fs/quota/dquot.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 6e429fdda17..10cbe841cb7 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -116,15 +116,15 @@
* spinlock to internal buffers before writing.
*
* Lock ordering (including related VFS locks) is the following:
- * i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
+ * dqonoff_mutex > i_mutex > journal_lock > dqptr_sem > dquot->dq_lock >
* dqio_mutex
+ * dqonoff_mutex > i_mutex comes from dquot_quota_sync, dquot_enable, etc.
* The lock ordering of dqptr_sem imposed by quota code is only dqonoff_sem >
* dqptr_sem. But filesystem has to count with the fact that functions such as
* dquot_alloc_space() acquire dqptr_sem and they usually have to be called
* from inside a transaction to keep filesystem consistency after a crash. Also
* filesystems usually want to do some IO on dquot from ->mark_dirty which is
* called with dqptr_sem held.
- * i_mutex on quota files is special (it's below dqio_mutex)
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
@@ -658,8 +658,7 @@ int dquot_quota_sync(struct super_block *sb, int type, int wait)
continue;
if (!sb_has_quota_active(sb, cnt))
continue;
- mutex_lock_nested(&dqopt->files[cnt]->i_mutex,
- I_MUTEX_QUOTA);
+ mutex_lock(&dqopt->files[cnt]->i_mutex);
truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
mutex_unlock(&dqopt->files[cnt]->i_mutex);
}
@@ -2037,8 +2036,7 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags)
/* If quota was reenabled in the meantime, we have
* nothing to do */
if (!sb_has_quota_loaded(sb, cnt)) {
- mutex_lock_nested(&toputinode[cnt]->i_mutex,
- I_MUTEX_QUOTA);
+ mutex_lock(&toputinode[cnt]->i_mutex);
toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
S_NOATIME | S_NOQUOTA);
truncate_inode_pages(&toputinode[cnt]->i_data,
@@ -2133,7 +2131,7 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
/* We don't want quota and atime on quota files (deadlocks
* possible) Also nobody should write to the file - we use
* special IO operations which ignore the immutable bit. */
- mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
+ mutex_lock(&inode->i_mutex);
oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE |
S_NOQUOTA);
inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
@@ -2180,7 +2178,7 @@ out_file_init:
iput(inode);
out_lock:
if (oldflags != -1) {
- mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
+ mutex_lock(&inode->i_mutex);
/* Set the flags back (in the case of accidental quotaon()
* on a wrong file we don't want to mess up the flags) */
inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);