Merge branch 'sched/urgent' into sched/core

Merge reason: Pick up fixes that did not make it into .32.0

Signed-off-by: Ingo Molnar <mingo@elte.hu>

43 files changed, 472 insertions, 212 deletions

diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 873cd31baa4..15cce53bf61 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -40,6 +40,24 @@
 #include "fid.h"
 
 /**
+ * struct p9_rdir - readdir accounting
+ * @mutex: mutex protecting readdir
+ * @head: start offset of current dirread buffer
+ * @tail: end offset of current dirread buffer
+ * @buf: dirread buffer
+ *
+ * private structure for keeping track of readdir
+ * allocated on demand
+ */
+
+struct p9_rdir {
+	struct mutex mutex;
+	int head;
+	int tail;
+	uint8_t *buf;
+};
+
+/**
  * dt_type - return file type
  * @mistat: mistat structure
  *
@@ -70,56 +88,79 @@ static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 {
 	int over;
 	struct p9_wstat st;
-	int err;
+	int err = 0;
 	struct p9_fid *fid;
 	int buflen;
-	char *statbuf;
-	int n, i = 0;
+	int reclen = 0;
+	struct p9_rdir *rdir;
 
 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
 	fid = filp->private_data;
 
 	buflen = fid->clnt->msize - P9_IOHDRSZ;
-	statbuf = kmalloc(buflen, GFP_KERNEL);
-	if (!statbuf)
-		return -ENOMEM;
-
-	while (1) {
-		err = v9fs_file_readn(filp, statbuf, NULL, buflen,
-								fid->rdir_fpos);
-		if (err <= 0)
-			break;
-
-		n = err;
-		while (i < n) {
-			err = p9stat_read(statbuf + i, buflen-i, &st,
-							fid->clnt->dotu);
+
+	/* allocate rdir on demand */
+	if (!fid->rdir) {
+		rdir = kmalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
+
+		if (rdir == NULL) {
+			err = -ENOMEM;
+			goto exit;
+		}
+		spin_lock(&filp->f_dentry->d_lock);
+		if (!fid->rdir) {
+			rdir->buf = (uint8_t *)rdir + sizeof(struct p9_rdir);
+			mutex_init(&rdir->mutex);
+			rdir->head = rdir->tail = 0;
+			fid->rdir = (void *) rdir;
+			rdir = NULL;
+		}
+		spin_unlock(&filp->f_dentry->d_lock);
+		kfree(rdir);
+	}
+	rdir = (struct p9_rdir *) fid->rdir;
+
+	err = mutex_lock_interruptible(&rdir->mutex);
+	while (err == 0) {
+		if (rdir->tail == rdir->head) {
+			err = v9fs_file_readn(filp, rdir->buf, NULL,
+							buflen, filp->f_pos);
+			if (err <= 0)
+				goto unlock_and_exit;
+
+			rdir->head = 0;
+			rdir->tail = err;
+		}
+
+		while (rdir->head < rdir->tail) {
+			err = p9stat_read(rdir->buf + rdir->head,
+						buflen - rdir->head, &st,
+						fid->clnt->dotu);
 			if (err) {
 				P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
 				err = -EIO;
 				p9stat_free(&st);
-				goto free_and_exit;
+				goto unlock_and_exit;
 			}
-
-			i += st.size+2;
-			fid->rdir_fpos += st.size+2;
+			reclen = st.size+2;
 
 			over = filldir(dirent, st.name, strlen(st.name),
 			    filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
 
-			filp->f_pos += st.size+2;
-
 			p9stat_free(&st);
 
 			if (over) {
 				err = 0;
-				goto free_and_exit;
+				goto unlock_and_exit;
 			}
+			rdir->head += reclen;
+			filp->f_pos += reclen;
 		}
 	}
 
-free_and_exit:
-	kfree(statbuf);
+unlock_and_exit:
+	mutex_unlock(&rdir->mutex);
+exit:
 	return err;
 }
 
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 5947628aefe..18f74ec4dce 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -994,8 +994,7 @@ static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
 	P9_DPRINTK(P9_DEBUG_VFS,
 		"%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
 
-	retval = buflen;
-
+	retval = strnlen(buffer, buflen);
 done:
 	kfree(st);
 	return retval;
@@ -1062,7 +1061,7 @@ static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 			__putname(link);
 			link = ERR_PTR(len);
 		} else
-			link[len] = 0;
+			link[min(len, PATH_MAX-1)] = 0;
 	}
 	nd_set_link(nd, link);
 
diff --git a/fs/Kconfig b/fs/Kconfig
index d4bf8caad8d..64d44efad7a 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -135,8 +135,8 @@ config TMPFS_POSIX_ACL
 
 config HUGETLBFS
 	bool "HugeTLB file system support"
-	depends on X86 || IA64 || PPC64 || SPARC64 || (SUPERH && MMU) || \
-		   (S390 && 64BIT) || SYS_SUPPORTS_HUGETLBFS || BROKEN
+	depends on X86 || IA64 || SPARC64 || (S390 && 64BIT) || \
+		   SYS_SUPPORTS_HUGETLBFS || BROKEN
 	help
 	  hugetlbfs is a filesystem backing for HugeTLB pages, based on
 	  ramfs. For architectures that support it, say Y here and read
diff --git a/fs/bio.c b/fs/bio.c
index 402cb84a92a..12da5db8682 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -325,8 +325,16 @@ static void bio_fs_destructor(struct bio *bio)
  *	@gfp_mask: allocation mask to use
  *	@nr_iovecs: number of iovecs
  *
- *	Allocate a new bio with @nr_iovecs bvecs.  If @gfp_mask
- *	contains __GFP_WAIT, the allocation is guaranteed to succeed.
+ *	bio_alloc will allocate a bio and associated bio_vec array that can hold
+ *	at least @nr_iovecs entries. Allocations will be done from the
+ *	fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc.
+ *
+ *	If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
+ *	a bio. This is due to the mempool guarantees. To make this work, callers
+ *	must never allocate more than 1 bio at a time from this pool. Callers
+ *	that need to allocate more than 1 bio must always submit the previously
+ *	allocated bio for IO before attempting to allocate a new one. Failure to
+ *	do so can cause livelocks under memory pressure.
  *
  *	RETURNS:
  *	Pointer to new bio on success, NULL on failure.
@@ -350,21 +358,13 @@ static void bio_kmalloc_destructor(struct bio *bio)
 }
 
 /**
- * bio_alloc - allocate a bio for I/O
+ * bio_kmalloc - allocate a bio for I/O using kmalloc()
  * @gfp_mask:   the GFP_ mask given to the slab allocator
  * @nr_iovecs:	number of iovecs to pre-allocate
  *
  * Description:
- *   bio_alloc will allocate a bio and associated bio_vec array that can hold
- *   at least @nr_iovecs entries. Allocations will be done from the
- *   fs_bio_set. Also see @bio_alloc_bioset.
- *
- *   If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
- *   a bio. This is due to the mempool guarantees. To make this work, callers
- *   must never allocate more than 1 bio at a time from this pool. Callers
- *   that need to allocate more than 1 bio must always submit the previously
- *   allocated bio for IO before attempting to allocate a new one. Failure to
- *   do so can cause livelocks under memory pressure.
+ *   Allocate a new bio with @nr_iovecs bvecs.  If @gfp_mask contains
+ *   %__GFP_WAIT, the allocation is guaranteed to succeed.
  *
  **/
 struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
@@ -407,7 +407,7 @@ EXPORT_SYMBOL(zero_fill_bio);
  *
  * Description:
  *   Put a reference to a &struct bio, either one you have gotten with
- *   bio_alloc or bio_get. The last put of a bio will free it.
+ *   bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
  **/
 void bio_put(struct bio *bio)
 {
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9cf4b926f8e..8bed0557d88 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1248,8 +1248,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 			bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
 		}
 	} else {
-		put_disk(disk);
 		module_put(disk->fops->owner);
+		put_disk(disk);
 		disk = NULL;
 		if (bdev->bd_contains == bdev) {
 			if (bdev->bd_disk->fops->open) {
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e238a0cdac6..94627c4cc19 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2977,10 +2977,10 @@ static int maybe_allocate_chunk(struct btrfs_root *root,
 
 	free_space = btrfs_super_total_bytes(disk_super);
 	/*
-	 * we allow the metadata to grow to a max of either 5gb or 5% of the
+	 * we allow the metadata to grow to a max of either 10gb or 5% of the
 	 * space in the volume.
 	 */
-	min_metadata = min((u64)5 * 1024 * 1024 * 1024,
+	min_metadata = min((u64)10 * 1024 * 1024 * 1024,
 			     div64_u64(free_space * 5, 100));
 	if (info->total_bytes >= min_metadata) {
 		spin_unlock(&info->lock);
@@ -4102,7 +4102,7 @@ wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
 }
 
 enum btrfs_loop_type {
-	LOOP_CACHED_ONLY = 0,
+	LOOP_FIND_IDEAL = 0,
 	LOOP_CACHING_NOWAIT = 1,
 	LOOP_CACHING_WAIT = 2,
 	LOOP_ALLOC_CHUNK = 3,
@@ -4131,12 +4131,15 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
 	struct btrfs_block_group_cache *block_group = NULL;
 	int empty_cluster = 2 * 1024 * 1024;
 	int allowed_chunk_alloc = 0;
+	int done_chunk_alloc = 0;
 	struct btrfs_space_info *space_info;
 	int last_ptr_loop = 0;
 	int loop = 0;
 	bool found_uncached_bg = false;
 	bool failed_cluster_refill = false;
 	bool failed_alloc = false;
+	u64 ideal_cache_percent = 0;
+	u64 ideal_cache_offset = 0;
 
 	WARN_ON(num_bytes < root->sectorsize);
 	btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
@@ -4172,14 +4175,19 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
 		empty_cluster = 0;
 
 	if (search_start == hint_byte) {
+ideal_cache:
 		block_group = btrfs_lookup_block_group(root->fs_info,
 						       search_start);
 		/*
 		 * we don't want to use the block group if it doesn't match our
 		 * allocation bits, or if its not cached.
+		 *
+		 * However if we are re-searching with an ideal block group
+		 * picked out then we don't care that the block group is cached.
 		 */
 		if (block_group && block_group_bits(block_group, data) &&
-		    block_group_cache_done(block_group)) {
+		    (block_group->cached != BTRFS_CACHE_NO ||
+		     search_start == ideal_cache_offset)) {
 			down_read(&space_info->groups_sem);
 			if (list_empty(&block_group->list) ||
 			    block_group->ro) {
@@ -4191,13 +4199,13 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
 				 */
 				btrfs_put_block_group(block_group);
 				up_read(&space_info->groups_sem);
-			} else
+			} else {
 				goto have_block_group;
+			}
 		} else if (block_group) {
 			btrfs_put_block_group(block_group);
 		}
 	}
-
 search:
 	down_read(&space_info->groups_sem);
 	list_for_each_entry(block_group, &space_info->block_groups, list) {
@@ -4209,28 +4217,45 @@ search:
 
 have_block_group:
 		if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
+			u64 free_percent;
+
+			free_percent = btrfs_block_group_used(&block_group->item);
+			free_percent *= 100;
+			free_percent = div64_u64(free_percent,
+						 block_group->key.offset);
+			free_percent = 100 - free_percent;
+			if (free_percent > ideal_cache_percent &&
+			    likely(!block_group->ro)) {
+				ideal_cache_offset = block_group->key.objectid;
+				ideal_cache_percent = free_percent;
+			}
+
 			/*
-			 * we want to start caching kthreads, but not too many
-			 * right off the bat so we don't overwhelm the system,
-			 * so only start them if there are less than 2 and we're
-			 * in the initial allocation phase.
+			 * We only want to start kthread caching if we are at
+			 * the point where we will wait for caching to make
+			 * progress, or if our ideal search is over and we've
+			 * found somebody to start caching.
 			 */
 			if (loop > LOOP_CACHING_NOWAIT ||
-			    atomic_read(&space_info->caching_threads) < 2) {
+			    (loop > LOOP_FIND_IDEAL &&
+			     atomic_read(&space_info->caching_threads) < 2)) {
 				ret = cache_block_group(block_group);
 				BUG_ON(ret);
 			}
-		}
-
-		cached = block_group_cache_done(block_group);
-		if (unlikely(!cached)) {
 			found_uncached_bg = true;
 
-			/* if we only want cached bgs, loop */
-			if (loop == LOOP_CACHED_ONLY)
+			/*
+			 * If loop is set for cached only, try the next block
+			 * group.
+			 */
+			if (loop == LOOP_FIND_IDEAL)
 				goto loop;
 		}
 
+		cached = block_group_cache_done(block_group);
+		if (unlikely(!cached))
+			found_uncached_bg = true;
+
 		if (unlikely(block_group->ro))
 			goto loop;
 
@@ -4410,9 +4435,11 @@ loop:
 	}
 	up_read(&space_info->groups_sem);
 
-	/* LOOP_CACHED_ONLY, only search fully cached block groups
-	 * LOOP_CACHING_NOWAIT, search partially cached block groups, but
-	 *			dont wait foR them to finish caching
+	/* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
+	 *			for them to make caching progress.  Also
+	 *			determine the best possible bg to cache
+	 * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
+	 *			caching kthreads as we move along
 	 * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
 	 * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
 	 * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
@@ -4421,12 +4448,47 @@ loop:
 	if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE &&
 	    (found_uncached_bg || empty_size || empty_cluster ||
 	     allowed_chunk_alloc)) {
-		if (found_uncached_bg) {
+		if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
 			found_uncached_bg = false;
-			if (loop < LOOP_CACHING_WAIT) {
-				loop++;
+			loop++;
+			if (!ideal_cache_percent &&
+			    atomic_read(&space_info->caching_threads))
 				goto search;
-			}
+
+			/*
+			 * 1 of the following 2 things have happened so far
+			 *
+			 * 1) We found an ideal block group for caching that
+			 * is mostly full and will cache quickly, so we might
+			 * as well wait for it.
+			 *
+			 * 2) We searched for cached only and we didn't find
+			 * anything, and we didn't start any caching kthreads
+			 * either, so chances are we will loop through and
+			 * start a couple caching kthreads, and then come back
+			 * around and just wait for them.  This will be slower
+			 * because we will have 2 caching kthreads reading at
+			 * the same time when we could have just started one
+			 * and waited for it to get far enough to give us an
+			 * allocation, so go ahead and go to the wait caching
+			 * loop.
+			 */
+			loop = LOOP_CACHING_WAIT;
+			search_start = ideal_cache_offset;
+			ideal_cache_percent = 0;
+			goto ideal_cache;
+		} else if (loop == LOOP_FIND_IDEAL) {
+			/*
+			 * Didn't find a uncached bg, wait on anything we find
+			 * next.
+			 */
+			loop = LOOP_CACHING_WAIT;
+			goto search;
+		}
+
+		if (loop < LOOP_CACHING_WAIT) {
+			loop++;
+			goto search;
 		}
 
 		if (loop == LOOP_ALLOC_CHUNK) {
@@ -4438,7 +4500,8 @@ loop:
 			ret = do_chunk_alloc(trans, root, num_bytes +
 					     2 * 1024 * 1024, data, 1);
 			allowed_chunk_alloc = 0;
-		} else {
+			done_chunk_alloc = 1;
+		} else if (!done_chunk_alloc) {
 			space_info->force_alloc = 1;
 		}
 
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 2c726b7b9fa..ccbdcb54ec5 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -208,7 +208,7 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
 	write_lock(&tree->lock);
 	em = lookup_extent_mapping(tree, start, len);
 
-	WARN_ON(em->start != start || !em);
+	WARN_ON(!em || em->start != start);
 
 	if (!em)
 		goto out;
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 5c2caad7621..cb2849f0325 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1296,7 +1296,7 @@ again:
 			window_start = entry->offset;
 			window_free = entry->bytes;
 			last = entry;
-			max_extent = 0;
+			max_extent = entry->bytes;
 		} else {
 			last = next;
 			window_free += next->bytes;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dae12dc7e15..b3ad168a0bf 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -538,7 +538,7 @@ static noinline int submit_compressed_extents(struct inode *inode,
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 	struct extent_io_tree *io_tree;
-	int ret;
+	int ret = 0;
 
 	if (list_empty(&async_cow->extents))
 		return 0;
@@ -552,6 +552,7 @@ static noinline int submit_compressed_extents(struct inode *inode,
 
 		io_tree = &BTRFS_I(inode)->io_tree;
 
+retry:
 		/* did the compression code fall back to uncompressed IO? */
 		if (!async_extent->pages) {
 			int page_started = 0;
@@ -562,11 +563,11 @@ static noinline int submit_compressed_extents(struct inode *inode,
 				    async_extent->ram_size - 1, GFP_NOFS);
 
 			/* allocate blocks */
-			cow_file_range(inode, async_cow->locked_page,
-				       async_extent->start,
-				       async_extent->start +
-				       async_extent->ram_size - 1,
-				       &page_started, &nr_written, 0);
+			ret = cow_file_range(inode, async_cow->locked_page,
+					     async_extent->start,
+					     async_extent->start +
+					     async_extent->ram_size - 1,
+					     &page_started, &nr_written, 0);
 
 			/*
 			 * if page_started, cow_file_range inserted an
@@ -574,7 +575,7 @@ static noinline int submit_compressed_extents(struct inode *inode,
 			 * and IO for us.  Otherwise, we need to submit
 			 * all those pages down to the drive.
 			 */
-			if (!page_started)
+			if (!page_started && !ret)
 				extent_write_locked_range(io_tree,
 						  inode, async_extent->start,
 						  async_extent->start +
@@ -602,7 +603,21 @@ static noinline int submit_compressed_extents(struct inode *inode,
 					   async_extent->compressed_size,
 					   0, alloc_hint,
 					   (u64)-1, &ins, 1);
-		BUG_ON(ret);
+		if (ret) {
+			int i;
+			for (i = 0; i < async_extent->nr_pages; i++) {
+				WARN_ON(async_extent->pages[i]->mapping);
+				page_cache_release(async_extent->pages[i]);
+			}
+			kfree(async_extent->pages);
+			async_extent->nr_pages = 0;
+			async_extent->pages = NULL;
+			unlock_extent(io_tree, async_extent->start,
+				      async_extent->start +
+				      async_extent->ram_size - 1, GFP_NOFS);
+			goto retry;
+		}
+
 		em = alloc_extent_map(GFP_NOFS);
 		em->start = async_extent->start;
 		em->len = async_extent->ram_size;
@@ -743,8 +758,22 @@ static noinline int cow_file_range(struct inode *inode,
 	em = search_extent_mapping(&BTRFS_I(inode)->extent_tree,
 				   start, num_bytes);
 	if (em) {
-		alloc_hint = em->block_start;
-		free_extent_map(em);
+		/*
+		 * if block start isn't an actual block number then find the
+		 * first block in this inode and use that as a hint.  If that
+		 * block is also bogus then just don't worry about it.
+		 */
+		if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
+			free_extent_map(em);
+			em = search_extent_mapping(em_tree, 0, 0);
+			if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
+				alloc_hint = em->block_start;
+			if (em)
+				free_extent_map(em);
+		} else {
+			alloc_hint = em->block_start;
+			free_extent_map(em);
+		}
 	}
 	read_unlock(&BTRFS_I(inode)->extent_tree.lock);
 	btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
@@ -2474,7 +2503,19 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
 
 	root = BTRFS_I(dir)->root;
 
+	/*
+	 * 5 items for unlink inode
+	 * 1 for orphan
+	 */
+	ret = btrfs_reserve_metadata_space(root, 6);
+	if (ret)
+		return ret;
+
 	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		btrfs_unreserve_metadata_space(root, 6);
+		return PTR_ERR(trans);
+	}
 
 	btrfs_set_trans_block_group(trans, dir);
 
@@ -2489,6 +2530,7 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
 	nr = trans->blocks_used;
 
 	btrfs_end_transaction_throttle(trans, root);
+	btrfs_unreserve_metadata_space(root, 6);
 	btrfs_btree_balance_dirty(root, nr);
 	return ret;
 }
@@ -2569,7 +2611,16 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 	    inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
 		return -ENOTEMPTY;
 
+	ret = btrfs_reserve_metadata_space(root, 5);
+	if (ret)
+		return ret;
+
 	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		btrfs_unreserve_metadata_space(root, 5);
+		return PTR_ERR(trans);
+	}
+
 	btrfs_set_trans_block_group(trans, dir);
 
 	if (unlikely(inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
@@ -2592,6 +2643,7 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 out:
 	nr = trans->blocks_used;
 	ret = btrfs_end_transaction_throttle(trans, root);
+	btrfs_unreserve_metadata_space(root, 5);
 	btrfs_btree_balance_dirty(root, nr);
 
 	if (ret && !err)
@@ -5128,6 +5180,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
 	ei->logged_trans = 0;
 	ei->outstanding_extents = 0;
 	ei->reserved_extents = 0;
+	ei->root = NULL;
 	spin_lock_init(&ei->accounting_lock);
 	btrfs_ordered_inode_tree_init(&ei->ordered_tree);
 	INIT_LIST_HEAD(&ei->i_orphan);
@@ -5144,6 +5197,14 @@ void btrfs_destroy_inode(struct inode *inode)
 	WARN_ON(inode->i_data.nrpages);
 
 	/*
+	 * This can happen where we create an inode, but somebody else also
+	 * created the same inode and we need to destroy the one we already
+	 * created.
+	 */
+	if (!root)
+		goto free;
+
+	/*
 	 * Make sure we're properly removed from the ordered operation
 	 * lists.
 	 */
@@ -5178,6 +5239,7 @@ void btrfs_destroy_inode(struct inode *inode)
 	}
 	inode_tree_del(inode);
 	btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
+free:
 	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
@@ -5283,11 +5345,14 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		return -ENOTEMPTY;
 
 	/*
-	 * 2 items for dir items
-	 * 1 item for orphan entry
-	 * 1 item for ref
+	 * We want to reserve the absolute worst case amount of items.  So if
+	 * both inodes are subvols and we need to unlink them then that would
+	 * require 4 item modifications, but if they are both normal inodes it
+	 * would require 5 item modifications, so we'll assume their normal
+	 * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
+	 * should cover the worst case number of items we'll modify.
 	 */
-	ret = btrfs_reserve_metadata_space(root, 4);
+	ret = btrfs_reserve_metadata_space(root, 11);
 	if (ret)
 		return ret;
 
@@ -5403,7 +5468,7 @@ out_fail:
 	if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
 		up_read(&root->fs_info->subvol_sem);
 
-	btrfs_unreserve_metadata_space(root, 4);
+	btrfs_unreserve_metadata_space(root, 11);
 	return ret;
 }
 
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 9351428f30e..67fa2d29d66 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -159,7 +159,6 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 	write_extent_buffer(l, item, ptr, sizeof(*item));
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 out:
-	btrfs_release_path(root, path);
 	btrfs_free_path(path);
 	return ret;
 }
@@ -332,7 +331,6 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	BUG_ON(refs != 0);
 	ret = btrfs_del_item(trans, root, path);
 out:
-	btrfs_release_path(root, path);
 	btrfs_free_path(path);
 	return ret;
 }
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index bca82a4ca8e..c207e8c32c9 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -163,8 +163,14 @@ static void wait_current_trans(struct btrfs_root *root)
 	}
 }
 
+enum btrfs_trans_type {
+	TRANS_START,
+	TRANS_JOIN,
+	TRANS_USERSPACE,
+};
+
 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
-					     int num_blocks, int wait)
+					     int num_blocks, int type)
 {
 	struct btrfs_trans_handle *h =
 		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
@@ -172,7 +178,8 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 
 	mutex_lock(&root->fs_info->trans_mutex);
 	if (!root->fs_info