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authorJan Kara <jack@suse.cz>2010-03-31 16:25:37 +0200
committerJan Kara <jack@suse.cz>2010-05-21 19:30:47 +0200
commitfb8dd8d780140a3f0e9074831a59054fec6cc451 (patch)
tree09e9f7bf157784fc6b0a7df71c1fbfe711349055 /fs/ocfs2/quota.h
parentae4f6ef13417deaa49471c0e903914a3ef3be258 (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.h5
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;