diff options
| -rw-r--r-- | fs/fs-writeback.c | 11 | ||||
| -rw-r--r-- | fs/super.c | 1 | ||||
| -rw-r--r-- | include/linux/fs.h | 2 |
3 files changed, 14 insertions, 0 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index f45bf876579f..3c974442bdf0 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2114,6 +2114,15 @@ out_unlock_inode: } EXPORT_SYMBOL(__mark_inode_dirty); +/* + * The @s_sync_lock is used to serialise concurrent sync operations + * to avoid lock contention problems with concurrent wait_sb_inodes() calls. + * Concurrent callers will block on the s_sync_lock rather than doing contending + * walks. The queueing maintains sync(2) required behaviour as all the IO that + * has been issued up to the time this function is enter is guaranteed to be + * completed by the time we have gained the lock and waited for all IO that is + * in progress regardless of the order callers are granted the lock. + */ static void wait_sb_inodes(struct super_block *sb) { struct inode *inode, *old_inode = NULL; @@ -2124,6 +2133,7 @@ static void wait_sb_inodes(struct super_block *sb) */ WARN_ON(!rwsem_is_locked(&sb->s_umount)); + mutex_lock(&sb->s_sync_lock); spin_lock(&sb->s_inode_list_lock); /* @@ -2165,6 +2175,7 @@ static void wait_sb_inodes(struct super_block *sb) } spin_unlock(&sb->s_inode_list_lock); iput(old_inode); + mutex_unlock(&sb->s_sync_lock); } static void __writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr, diff --git a/fs/super.c b/fs/super.c index c808183554a2..fd427ec0b372 100644 --- a/fs/super.c +++ b/fs/super.c @@ -190,6 +190,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags) s->s_flags = flags; INIT_HLIST_NODE(&s->s_instances); INIT_HLIST_BL_HEAD(&s->s_anon); + mutex_init(&s->s_sync_lock); INIT_LIST_HEAD(&s->s_inodes); spin_lock_init(&s->s_inode_list_lock); diff --git a/include/linux/fs.h b/include/linux/fs.h index 09bbd38485f9..82dfc5519b4b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1375,6 +1375,8 @@ struct super_block { struct list_lru s_inode_lru ____cacheline_aligned_in_smp; struct rcu_head rcu; + struct mutex s_sync_lock; /* sync serialisation lock */ + /* * Indicates how deep in a filesystem stack this SB is */ |