Merge branch 'writeback-workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq into for-3.10/core

Tejun writes:

-----

This is the pull request for the earlier patchset[1] with the same
name.  It's only three patches (the first one was committed to
workqueue tree) but the merge strategy is a bit involved due to the
dependencies.

* Because the conversion needs features from wq/for-3.10,
  block/for-3.10/core is based on rc3, and wq/for-3.10 has conflicts
  with rc3, I pulled mainline (rc5) into wq/for-3.10 to prevent those
  workqueue conflicts from flaring up in block tree.

* Resolving the issue that Jan and Dave raised about debugging
  requires arch-wide changes.  The patchset is being worked on[2] but
  it'll have to go through -mm after these changes show up in -next,
  and not included in this pull request.

The three commits are located in the following git branch.

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git writeback-workqueue

Pulling it into block/for-3.10/core produces a conflict in
drivers/md/raid5.c between the following two commits.

  e3620a3ad5 ("MD RAID5: Avoid accessing gendisk or queue structs when not available")
  2f6db2a707 ("raid5: use bio_reset()")

The conflict is trivial - one removes an "if ()" conditional while the
other removes "rbi->bi_next = NULL" right above it.  We just need to
remove both.  The merged branch is available at

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git block-test-merge

so that you can use it for verification.  The test merge commit has
proper merge description.

While these changes are a bit of pain to route, they make code simpler
and even have, while minute, measureable performance gain[3] even on a
workload which isn't particularly favorable to showing the benefits of
this conversion.

----

Fixed up the conflict.

Conflicts:
	drivers/md/raid5.c

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 10 insertions, 4 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7d84651..6d19a0a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1291,6 +1291,7 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 				      0, objectid, NULL, 0, 0, 0);
 	if (IS_ERR(leaf)) {
 		ret = PTR_ERR(leaf);
+		leaf = NULL;
 		goto fail;
 	}
 
@@ -1334,11 +1335,16 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 
 	btrfs_tree_unlock(leaf);
 
+	return root;
+
 fail:
-	if (ret)
-		return ERR_PTR(ret);
+	if (leaf) {
+		btrfs_tree_unlock(leaf);
+		free_extent_buffer(leaf);
+	}
+	kfree(root);
 
-	return root;
+	return ERR_PTR(ret);
 }
 
 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
@@ -3253,7 +3259,7 @@ void btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
 	if (btrfs_root_refs(&root->root_item) == 0)
 		synchronize_srcu(&fs_info->subvol_srcu);
 
-	if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 		btrfs_free_log(NULL, root);
 		btrfs_free_log_root_tree(NULL, fs_info);
 	}