Btrfs: split the global ordered extents mutex

When we create a snapshot, we just need wait the ordered extents in
the source fs/file root, but because we use the global mutex to protect
this ordered extents list of the source fs/file root to avoid accessing
a empty list, if someone got the mutex to access the ordered extents list
of the other fs/file root, we had to wait.

This patch splits the above global mutex, now every fs/file root has
its own mutex to protect its own list.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5a80098..5f49215 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1814,6 +1814,8 @@ struct btrfs_root {
        struct list_head delalloc_inodes;
        struct list_head delalloc_root;
        u64 nr_delalloc_inodes;
+
+       struct mutex ordered_extent_mutex;
        /*
         * this is used by the balancing code to wait for all the pending
         * ordered extents

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7d09ca4..237b5b5 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1220,6 +1220,7 @@ static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
        spin_lock_init(&root->log_extents_lock[1]);
        mutex_init(&root->objectid_mutex);
        mutex_init(&root->log_mutex);
+       mutex_init(&root->ordered_extent_mutex);
        init_waitqueue_head(&root->log_writer_wait);
        init_waitqueue_head(&root->log_commit_wait[0]);
        init_waitqueue_head(&root->log_commit_wait[1]);

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index a75eaa2..a94b05f 100644 (file)
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -595,7 +595,7 @@ static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
  * wait for all the ordered extents in a root.  This is done when balancing
  * space between drives.
  */
-static int __btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
+int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
 {
        struct list_head splice, works;
        struct btrfs_ordered_extent *ordered, *next;
@@ -604,6 +604,7 @@ static int __btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
        INIT_LIST_HEAD(&splice);
        INIT_LIST_HEAD(&works);
 
+       mutex_lock(&root->ordered_extent_mutex);
        spin_lock(&root->ordered_extent_lock);
        list_splice_init(&root->ordered_extents, &splice);
        while (!list_empty(&splice) && nr) {
@@ -635,17 +636,7 @@ static int __btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
                btrfs_put_ordered_extent(ordered);
                cond_resched();
        }
-
-       return count;
-}
-
-int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
-{
-       int count;
-
-       mutex_lock(&root->fs_info->ordered_operations_mutex);
-       count = __btrfs_wait_ordered_extents(root, nr);
-       mutex_unlock(&root->fs_info->ordered_operations_mutex);
+       mutex_unlock(&root->ordered_extent_mutex);
 
        return count;
 }
@@ -670,7 +661,7 @@ void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr)
                               &fs_info->ordered_roots);
                spin_unlock(&fs_info->ordered_root_lock);
 
-               done = __btrfs_wait_ordered_extents(root, nr);
+               done = btrfs_wait_ordered_extents(root, nr);
                btrfs_put_fs_root(root);
 
                spin_lock(&fs_info->ordered_root_lock);