Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs fixes from Chris Mason:
 "I've split out the big send/receive update from my last pull request
  and now have just the fixes in my for-linus branch.  The send/recv
  branch will wander over to linux-next shortly though.

  The largest patches in this pull are Josef's patches to fix DIO
  locking problems and his patch to fix a crash during balance.  They
  are both well tested.

  The rest are smaller fixes that we've had queued.  The last rc came
  out while I was hacking new and exciting ways to recover from a
  misplaced rm -rf on my dev box, so these missed rc3."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (25 commits)
  Btrfs: fix that repair code is spuriously executed for transid failures
  Btrfs: fix ordered extent leak when failing to start a transaction
  Btrfs: fix a dio write regression
  Btrfs: fix deadlock with freeze and sync V2
  Btrfs: revert checksum error statistic which can cause a BUG()
  Btrfs: remove superblock writing after fatal error
  Btrfs: allow delayed refs to be merged
  Btrfs: fix enospc problems when deleting a subvol
  Btrfs: fix wrong mtime and ctime when creating snapshots
  Btrfs: fix race in run_clustered_refs
  Btrfs: don't run __tree_mod_log_free_eb on leaves
  Btrfs: increase the size of the free space cache
  Btrfs: barrier before waitqueue_active
  Btrfs: fix deadlock in wait_for_more_refs
  btrfs: fix second lock in btrfs_delete_delayed_items()
  Btrfs: don't allocate a seperate csums array for direct reads
  Btrfs: do not strdup non existent strings
  Btrfs: do not use missing devices when showing devname
  Btrfs: fix that error value is changed by mistake
  Btrfs: lock extents as we map them in DIO
  ...

1 files changed, 6 insertions, 27 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e86ae04abe6a..88b969aeeb71 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -227,9 +227,8 @@ loop_lock:
                 cur = pending;
                 pending = pending->bi_next;
                 cur->bi_next = NULL;
-                atomic_dec(&fs_info->nr_async_bios);
 
-                if (atomic_read(&fs_info->nr_async_bios) < limit &&
+                if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
                     waitqueue_active(&fs_info->async_submit_wait))
                         wake_up(&fs_info->async_submit_wait);
 
@@ -569,9 +568,11 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
                 memcpy(new_device, device, sizeof(*new_device));
 
                 /* Safe because we are under uuid_mutex */
-                name = rcu_string_strdup(device->name->str, GFP_NOFS);
-                BUG_ON(device->name && !name); /* -ENOMEM */
-                rcu_assign_pointer(new_device->name, name);
+                if (device->name) {
+                        name = rcu_string_strdup(device->name->str, GFP_NOFS);
+                        BUG_ON(device->name && !name); /* -ENOMEM */
+                        rcu_assign_pointer(new_device->name, name);
+                }
                 new_device->bdev = NULL;
                 new_device->writeable = 0;
                 new_device->in_fs_metadata = 0;
@@ -4605,28 +4606,6 @@ int btrfs_read_sys_array(struct btrfs_root *root)
         return ret;
 }
 
-struct btrfs_device *btrfs_find_device_for_logical(struct btrfs_root *root,
-                                                   u64 logical, int mirror_num)
-{
-        struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
-        int ret;
-        u64 map_length = 0;
-        struct btrfs_bio *bbio = NULL;
-        struct btrfs_device *device;
-
-        BUG_ON(mirror_num == 0);
-        ret = btrfs_map_block(map_tree, WRITE, logical, &map_length, &bbio,
-                              mirror_num);
-        if (ret) {
-                BUG_ON(bbio != NULL);
-                return NULL;
-        }
-        BUG_ON(mirror_num != bbio->mirror_num);
-        device = bbio->stripes[mirror_num - 1].dev;
-        kfree(bbio);
-        return device;
-}
-
 int btrfs_read_chunk_tree(struct btrfs_root *root)
 {
         struct btrfs_path *path;