diff options
| author | Jan Kara <jack@suse.cz> | 2010-03-31 16:25:37 +0200 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2010-05-21 19:30:47 +0200 |
| commit | fb8dd8d780140a3f0e9074831a59054fec6cc451 (patch) | |
| tree | 09e9f7bf157784fc6b0a7df71c1fbfe711349055 /fs/ocfs2/quota.h | |
| parent | ae4f6ef13417deaa49471c0e903914a3ef3be258 (diff) | |
ocfs2: Fix quota locking
OCFS2 had three issues with quota locking:
a) When reading dquot from global quota file, we started a transaction while
holding dqio_mutex which is prone to deadlocks because other paths do it
the other way around
b) During ocfs2_sync_dquot we were not protected against concurrent writers
on the same node. Because we first copy data to local buffer, a race
could happen resulting in old data being written to global quota file and
thus causing quota inconsistency after a crash.
c) ip_alloc_sem of quota files was acquired while a transaction is started
in ocfs2_quota_write which can deadlock because we first get ip_alloc_sem
and then start a transaction when extending quota files.
We fix the problem a) by pulling all necessary code to ocfs2_acquire_dquot
and ocfs2_release_dquot. Thus we no longer depend on generic dquot_acquire
to do the locking and can force proper lock ordering.
Problems b) and c) are fixed by locking i_mutex and ip_alloc_sem of
global quota file in ocfs2_lock_global_qf and removing ip_alloc_sem from
ocfs2_quota_read and ocfs2_quota_write.
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ocfs2/quota.h')
| -rw-r--r-- | fs/ocfs2/quota.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/ocfs2/quota.h b/fs/ocfs2/quota.h index c7623430ca3..903ffa933d5 100644 --- a/fs/ocfs2/quota.h +++ b/fs/ocfs2/quota.h @@ -104,10 +104,11 @@ static inline int ocfs2_global_release_dquot(struct dquot *dquot) int ocfs2_lock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex); void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex); -int ocfs2_read_quota_block(struct inode *inode, u64 v_block, - struct buffer_head **bh); +int ocfs2_validate_quota_block(struct super_block *sb, struct buffer_head *bh); int ocfs2_read_quota_phys_block(struct inode *inode, u64 p_block, struct buffer_head **bh); +int ocfs2_create_local_dquot(struct dquot *dquot); +int ocfs2_local_release_dquot(handle_t *handle, struct dquot *dquot); extern const struct dquot_operations ocfs2_quota_operations; extern struct quota_format_type ocfs2_quota_format; |