diff options
Diffstat (limited to 'fs/fs-writeback.c')
| -rw-r--r-- | fs/fs-writeback.c | 11 |
1 files changed, 11 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, |