Drop stale btrfs revert patch

This was merged in 3.18-rc1 and we just forgot to drop it.

Revert-Btrfs-race-free-update-of-commit-root-for-ro-.patch

@@ -1,105 +0,0 @@
-From: Josh Boyer <jwboyer@fedoraproject.org>
-Date: Wed, 15 Oct 2014 10:09:50 -0400
-Subject: [PATCH] Revert "Btrfs: race free update of commit root for ro
- snapshots"
-
-This reverts commit 9c3b306e1c9e6be4be09e99a8fe2227d1005effc.
----
- fs/btrfs/inode.c | 36 ------------------------------------
- fs/btrfs/ioctl.c | 33 +++++++++++++++++++++++++++++++++
- 2 files changed, 33 insertions(+), 36 deletions(-)
-
-diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
-index fc9c0439caa3..d23362f4464e 100644
---- a/fs/btrfs/inode.c
-+++ b/fs/btrfs/inode.c
-@@ -5261,42 +5261,6 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
- 			iput(inode);
- 			inode = ERR_PTR(ret);
- 		}
--		/*
--		 * If orphan cleanup did remove any orphans, it means the tree
--		 * was modified and therefore the commit root is not the same as
--		 * the current root anymore. This is a problem, because send
--		 * uses the commit root and therefore can see inode items that
--		 * don't exist in the current root anymore, and for example make
--		 * calls to btrfs_iget, which will do tree lookups based on the
--		 * current root and not on the commit root. Those lookups will
--		 * fail, returning a -ESTALE error, and making send fail with
--		 * that error. So make sure a send does not see any orphans we
--		 * have just removed, and that it will see the same inodes
--		 * regardless of whether a transaction commit happened before
--		 * it started (meaning that the commit root will be the same as
--		 * the current root) or not.
--		 */
--		if (sub_root->node != sub_root->commit_root) {
--			u64 sub_flags = btrfs_root_flags(&sub_root->root_item);
--
--			if (sub_flags & BTRFS_ROOT_SUBVOL_RDONLY) {
--				struct extent_buffer *eb;
--
--				/*
--				 * Assert we can't have races between dentry
--				 * lookup called through the snapshot creation
--				 * ioctl and the VFS.
--				 */
--				ASSERT(mutex_is_locked(&dir->i_mutex));
--
--				down_write(&root->fs_info->commit_root_sem);
--				eb = sub_root->commit_root;
--				sub_root->commit_root =
--					btrfs_root_node(sub_root);
--				up_write(&root->fs_info->commit_root_sem);
--				free_extent_buffer(eb);
--			}
--		}
- 	}
- 
- 	return inode;
-diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
-index 0fe1aa047f15..8d2b76e29d3b 100644
---- a/fs/btrfs/ioctl.c
-+++ b/fs/btrfs/ioctl.c
-@@ -713,6 +713,39 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
- 	if (ret)
- 		goto fail;
- 
-+	ret = btrfs_orphan_cleanup(pending_snapshot->snap);
-+	if (ret)
-+		goto fail;
-+
-+	/*
-+	 * If orphan cleanup did remove any orphans, it means the tree was
-+	 * modified and therefore the commit root is not the same as the
-+	 * current root anymore. This is a problem, because send uses the
-+	 * commit root and therefore can see inode items that don't exist
-+	 * in the current root anymore, and for example make calls to
-+	 * btrfs_iget, which will do tree lookups based on the current root
-+	 * and not on the commit root. Those lookups will fail, returning a
-+	 * -ESTALE error, and making send fail with that error. So make sure
-+	 * a send does not see any orphans we have just removed, and that it
-+	 * will see the same inodes regardless of whether a transaction
-+	 * commit happened before it started (meaning that the commit root
-+	 * will be the same as the current root) or not.
-+	 */
-+	if (readonly && pending_snapshot->snap->node !=
-+	    pending_snapshot->snap->commit_root) {
-+		trans = btrfs_join_transaction(pending_snapshot->snap);
-+		if (IS_ERR(trans) && PTR_ERR(trans) != -ENOENT) {
-+			ret = PTR_ERR(trans);
-+			goto fail;
-+		}
-+		if (!IS_ERR(trans)) {
-+			ret = btrfs_commit_transaction(trans,
-+						       pending_snapshot->snap);
-+			if (ret)
-+				goto fail;
-+		}
-+	}
-+
- 	inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry);
- 	if (IS_ERR(inode)) {
- 		ret = PTR_ERR(inode);
--- 
-1.9.3
-