Merge branch 'for-chris' of git://repo.or.cz/linux-btrfs-devel into integration

Conflicts:
	fs/btrfs/volumes.c

Signed-off-by: Chris Mason <chris.mason@oracle.com>

6 files changed, 280 insertions, 226 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9c1a744e595b..e5167219c266 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2278,9 +2278,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	   (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
 	   BTRFS_UUID_SIZE);
 
-	mutex_lock(&fs_info->chunk_mutex);
 	ret = btrfs_read_chunk_tree(chunk_root);
-	mutex_unlock(&fs_info->chunk_mutex);
 	if (ret) {
 		printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
 		       sb->s_id);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 352083ad233c..1c1cf216be80 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7143,7 +7143,7 @@ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
 		 * space to fit our block group in.
 		 */
 		if (device->total_bytes > device->bytes_used + min_free) {
-			ret = find_free_dev_extent(NULL, device, min_free,
+			ret = find_free_dev_extent(device, min_free,
 						   &dev_offset, NULL);
 			if (!ret)
 				dev_nr++;
@@ -7505,6 +7505,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
 	ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
 				&cache->space_info);
 	BUG_ON(ret);
+	update_global_block_rsv(root->fs_info);
 
 	spin_lock(&cache->space_info->lock);
 	cache->space_info->bytes_readonly += cache->bytes_super;
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index ce40db59c706..6c7887a7770c 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -319,9 +319,11 @@ static void io_ctl_drop_pages(struct io_ctl *io_ctl)
 	io_ctl_unmap_page(io_ctl);
 
 	for (i = 0; i < io_ctl->num_pages; i++) {
-		ClearPageChecked(io_ctl->pages[i]);
-		unlock_page(io_ctl->pages[i]);
-		page_cache_release(io_ctl->pages[i]);
+		if (io_ctl->pages[i]) {
+			ClearPageChecked(io_ctl->pages[i]);
+			unlock_page(io_ctl->pages[i]);
+			page_cache_release(io_ctl->pages[i]);
+		}
 	}
 }
 
@@ -635,7 +637,10 @@ int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 	if (!num_entries)
 		return 0;
 
-	io_ctl_init(&io_ctl, inode, root);
+	ret = io_ctl_init(&io_ctl, inode, root);
+	if (ret)
+		return ret;
+
 	ret = readahead_cache(inode);
 	if (ret)
 		goto out;
@@ -838,7 +843,7 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 	struct io_ctl io_ctl;
 	struct list_head bitmap_list;
 	struct btrfs_key key;
-	u64 start, end, len;
+	u64 start, extent_start, extent_end, len;
 	int entries = 0;
 	int bitmaps = 0;
 	int ret;
@@ -849,7 +854,9 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 	if (!i_size_read(inode))
 		return -1;
 
-	io_ctl_init(&io_ctl, inode, root);
+	ret = io_ctl_init(&io_ctl, inode, root);
+	if (ret)
+		return -1;
 
 	/* Get the cluster for this block_group if it exists */
 	if (block_group && !list_empty(&block_group->cluster_list))
@@ -857,25 +864,12 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 				     struct btrfs_free_cluster,
 				     block_group_list);
 
-	/*
-	 * We shouldn't have switched the pinned extents yet so this is the
-	 * right one
-	 */
-	unpin = root->fs_info->pinned_extents;
-
 	/* Lock all pages first so we can lock the extent safely. */
 	io_ctl_prepare_pages(&io_ctl, inode, 0);
 
 	lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
 			 0, &cached_state, GFP_NOFS);
 
-	/*
-	 * When searching for pinned extents, we need to start at our start
-	 * offset.
-	 */
-	if (block_group)
-		start = block_group->key.objectid;
-
 	node = rb_first(&ctl->free_space_offset);
 	if (!node && cluster) {
 		node = rb_first(&cluster->root);
@@ -918,9 +912,20 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 	 * We want to add any pinned extents to our free space cache
 	 * so we don't leak the space
 	 */
+
+	/*
+	 * We shouldn't have switched the pinned extents yet so this is the
+	 * right one
+	 */
+	unpin = root->fs_info->pinned_extents;
+
+	if (block_group)
+		start = block_group->key.objectid;
+
 	while (block_group && (start < block_group->key.objectid +
 			       block_group->key.offset)) {
-		ret = find_first_extent_bit(unpin, start, &start, &end,
+		ret = find_first_extent_bit(unpin, start,
+					    &extent_start, &extent_end,
 					    EXTENT_DIRTY);
 		if (ret) {
 			ret = 0;
@@ -928,20 +933,21 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 		}
 
 		/* This pinned extent is out of our range */
-		if (start >= block_group->key.objectid +
+		if (extent_start >= block_group->key.objectid +
 		    block_group->key.offset)
 			break;
 
-		len = block_group->key.objectid +
-			block_group->key.offset - start;
-		len = min(len, end + 1 - start);
+		extent_start = max(extent_start, start);
+		extent_end = min(block_group->key.objectid +
+				 block_group->key.offset, extent_end + 1);
+		len = extent_end - extent_start;
 
 		entries++;
-		ret = io_ctl_add_entry(&io_ctl, start, len, NULL);
+		ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
 		if (ret)
 			goto out_nospc;
 
-		start = end + 1;
+		start = extent_end;
 	}
 
 	/* Write out the bitmaps */
@@ -2574,17 +2580,57 @@ void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
 	cluster->block_group = NULL;
 }
 
-int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
-			   u64 *trimmed, u64 start, u64 end, u64 minlen)
+static int do_trimming(struct btrfs_block_group_cache *block_group,
+		       u64 *total_trimmed, u64 start, u64 bytes,
+		       u64 reserved_start, u64 reserved_bytes)
 {
-	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
-	struct btrfs_free_space *entry = NULL;
+	struct btrfs_space_info *space_info = block_group->space_info;
 	struct btrfs_fs_info *fs_info = block_group->fs_info;
-	u64 bytes = 0;
-	u64 actually_trimmed;
-	int ret = 0;
+	int ret;
+	int update = 0;
+	u64 trimmed = 0;
 
-	*trimmed = 0;
+	spin_lock(&space_info->lock);
+	spin_lock(&block_group->lock);
+	if (!block_group->ro) {
+		block_group->reserved += reserved_bytes;
+		space_info->bytes_reserved += reserved_bytes;
+		update = 1;
+	}
+	spin_unlock(&block_group->lock);
+	spin_unlock(&space_info->lock);
+
+	ret = btrfs_error_discard_extent(fs_info->extent_root,
+					 start, bytes, &trimmed);
+	if (!ret)
+		*total_trimmed += trimmed;
+
+	btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
+
+	if (update) {
+		spin_lock(&space_info->lock);
+		spin_lock(&block_group->lock);
+		if (block_group->ro)
+			space_info->bytes_readonly += reserved_bytes;
+		block_group->reserved -= reserved_bytes;
+		space_info->bytes_reserved -= reserved_bytes;
+		spin_unlock(&space_info->lock);
+		spin_unlock(&block_group->lock);
+	}
+
+	return ret;
+}
+
+static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
+			  u64 *total_trimmed, u64 start, u64 end, u64 minlen)
+{
+	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
+	struct btrfs_free_space *entry;
+	struct rb_node *node;
+	int ret = 0;
+	u64 extent_start;
+	u64 extent_bytes;
+	u64 bytes;
 
 	while (start < end) {
 		spin_lock(&ctl->tree_lock);
@@ -2595,81 +2641,118 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 		}
 
 		entry = tree_search_offset(ctl, start, 0, 1);
-		if (!entry)
-			entry = tree_search_offset(ctl,
-						   offset_to_bitmap(ctl, start),
-						   1, 1);
-
-		if (!entry || entry->offset >= end) {
+		if (!entry) {
 			spin_unlock(&ctl->tree_lock);
 			break;
 		}
 
-		if (entry->bitmap) {
-			ret = search_bitmap(ctl, entry, &start, &bytes);
-			if (!ret) {
-				if (start >= end) {
-					spin_unlock(&ctl->tree_lock);
-					break;
-				}
-				bytes = min(bytes, end - start);
-				bitmap_clear_bits(ctl, entry, start, bytes);
-				if (entry->bytes == 0)
-					free_bitmap(ctl, entry);
-			} else {
-				start = entry->offset + BITS_PER_BITMAP *
-					block_group->sectorsize;
+		/* skip bitmaps */
+		while (entry->bitmap) {
+			node = rb_next(&entry->offset_index);
+			if (!node) {
 				spin_unlock(&ctl->tree_lock);
-				ret = 0;
-				continue;
+				goto out;
 			}
-		} else {
-			start = entry->offset;
-			bytes = min(entry->bytes, end - start);
-			unlink_free_space(ctl, entry);
-			kmem_cache_free(btrfs_free_space_cachep, entry);
+			entry = rb_entry(node, struct btrfs_free_space,
+					 offset_index);
+		}
+
+		if (entry->offset >= end) {
+			spin_unlock(&ctl->tree_lock);
+			break;
 		}
 
+		extent_start = entry->offset;
+		extent_bytes = entry->bytes;
+		start = max(start, extent_start);
+		bytes = min(extent_start + extent_bytes, end) - start;
+		if (bytes < minlen) {
+			spin_unlock(&ctl->tree_lock);
+			goto next;
+		}
+
+		unlink_free_space(ctl, entry);
+		kmem_cache_free(btrfs_free_space_cachep, entry);
+
 		spin_unlock(&ctl->tree_lock);
 
-		if (bytes >= minlen) {
-			struct btrfs_space_info *space_info;
-			int update = 0;
-
-			space_info = block_group->space_info;
-			spin_lock(&space_info->lock);
-			spin_lock(&block_group->lock);
-			if (!block_group->ro) {
-				block_group->reserved += bytes;
-				space_info->bytes_reserved += bytes;
-				update = 1;
-			}
-			spin_unlock(&block_group->lock);
-			spin_unlock(&space_info->lock);
-
-			ret = btrfs_error_discard_extent(fs_info->extent_root,
-							 start,
-							 bytes,
-							 &actually_trimmed);
-
-			btrfs_add_free_space(block_group, start, bytes);
-			if (update) {
-				spin_lock(&space_info->lock);
-				spin_lock(&block_group->lock);
-				if (block_group->ro)
-					space_info->bytes_readonly += bytes;
-				block_group->reserved -= bytes;
-				space_info->bytes_reserved -= bytes;
-				spin_unlock(&space_info->lock);
-				spin_unlock(&block_group->lock);
-			}
+		ret = do_trimming(block_group, total_trimmed, start, bytes,
+				  extent_start, extent_bytes);
+		if (ret)
+			break;
+next:
+		start += bytes;
 
-			if (ret)
-				break;
-			*trimmed += actually_trimmed;
+		if (fatal_signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+
+		cond_resched();
+	}
+out:
+	return ret;
+}
+
+static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
+			u64 *total_trimmed, u64 start, u64 end, u64 minlen)
+{
+	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
+	struct btrfs_free_space *entry;
+	int ret = 0;
+	int ret2;
+	u64 bytes;
+	u64 offset = offset_to_bitmap(ctl, start);
+
+	while (offset < end) {
+		bool next_bitmap = false;
+
+		spin_lock(&ctl->tree_lock);
+
+		if (ctl->free_space < minlen) {
+			spin_unlock(&ctl->tree_lock);
+			break;
+		}
+
+		entry = tree_search_offset(ctl, offset, 1, 0);
+		if (!entry) {
+			spin_unlock(&ctl->tree_lock);
+			next_bitmap = true;
+			goto next;
+		}
+
+		bytes = minlen;
+		ret2 = search_bitmap(ctl, entry, &start, &bytes);
+		if (ret2 || start >= end) {
+			spin_unlock(&ctl->tree_lock);
+			next_bitmap = true;
+			goto next;
+		}
+
+		bytes = min(bytes, end - start);
+		if (bytes < minlen) {
+			spin_unlock(&ctl->tree_lock);
+			goto next;
+		}
+
+		bitmap_clear_bits(ctl, entry, start, bytes);
+		if (entry->bytes == 0)
+			free_bitmap(ctl, entry);
+
+		spin_unlock(&ctl->tree_lock);
+
+		ret = do_trimming(block_group, total_trimmed, start, bytes,
+				  start, bytes);
+		if (ret)
+			break;
+next:
+		if (next_bitmap) {
+			offset += BITS_PER_BITMAP * ctl->unit;
+		} else {
+			start += bytes;
+			if (start >= offset + BITS_PER_BITMAP * ctl->unit)
+				offset += BITS_PER_BITMAP * ctl->unit;
 		}
-		start += bytes;
-		bytes = 0;
 
 		if (fatal_signal_pending(current)) {
 			ret = -ERESTARTSYS;
@@ -2682,6 +2765,22 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 	return ret;
 }
 
+int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
+			   u64 *trimmed, u64 start, u64 end, u64 minlen)
+{
+	int ret;
+
+	*trimmed = 0;
+
+	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
+	if (ret)
+		return ret;
+
+	ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
+
+	return ret;
+}
+
 /*
  * Find the left-most item in the cache tree, and then return the
  * smallest inode number in the item.
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 1e7a9bac31ab..ef909b5d3d2e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -176,6 +176,8 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 	struct btrfs_trans_handle *trans;
 	unsigned int flags, oldflags;
 	int ret;
+	u64 ip_oldflags;
+	unsigned int i_oldflags;
 
 	if (btrfs_root_readonly(root))
 		return -EROFS;
@@ -192,6 +194,9 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 
 	mutex_lock(&inode->i_mutex);
 
+	ip_oldflags = ip->flags;
+	i_oldflags = inode->i_flags;
+
 	flags = btrfs_mask_flags(inode->i_mode, flags);
 	oldflags = btrfs_flags_to_ioctl(ip->flags);
 	if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
@@ -249,19 +254,24 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 		ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
 	}
 
-	trans = btrfs_join_transaction(root);
-	BUG_ON(IS_ERR(trans));
+	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		goto out_drop;
+	}
 
 	btrfs_update_iflags(inode);
 	inode->i_ctime = CURRENT_TIME;
 	ret = btrfs_update_inode(trans, root, inode);
-	BUG_ON(ret);
 
 	btrfs_end_transaction(trans, root);
+ out_drop:
+	if (ret) {
+		ip->flags = ip_oldflags;
+		inode->i_flags = i_oldflags;
+	}
 
 	mnt_drop_write(file->f_path.mnt);
-
-	ret = 0;
  out_unlock:
 	mutex_unlock(&inode->i_mutex);
 	return ret;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9489a2aca47b..e0b7bb92a170 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -830,7 +830,6 @@ out:
 
 /*
  * find_free_dev_extent - find free space in the specified device
- * @trans:	transaction handler
  * @device:	the device which we search the free space in
  * @num_bytes:	the size of the free space that we need
  * @start:	store the start of the free space.
@@ -849,8 +848,7 @@ out:
  * But if we don't find suitable free space, it is used to store the size of
  * the max free space.
  */
-int find_free_dev_extent(struct btrfs_trans_handle *trans,
-			 struct btrfs_device *device, u64 num_bytes,
+int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 			 u64 *start, u64 *len)
 {
 	struct btrfs_key key;
@@ -894,7 +892,7 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans,
 	key.offset = search_start;
 	key.type = BTRFS_DEV_EXTENT_KEY;
 
-	ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
+	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
 		goto out;
 	if (ret > 0) {
@@ -1468,8 +1466,7 @@ error_undo:
 /*
  * does all the dirty work required for changing file system's UUID.
  */
-static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
-				struct btrfs_root *root)
+static int btrfs_prepare_sprout(struct btrfs_root *root)
 {
 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 	struct btrfs_fs_devices *old_devices;
@@ -1693,7 +1690,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 
 	if (seeding_dev) {
 		sb->s_flags &= ~MS_RDONLY;
-		ret = btrfs_prepare_sprout(trans, root);
+		ret = btrfs_prepare_sprout(root);
 		BUG_ON(ret);
 	}
 
@@ -3044,8 +3041,7 @@ done:
 	return ret;
 }
 
-static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
-			   struct btrfs_root *root,
+static int btrfs_add_system_chunk(struct btrfs_root *root,
 			   struct btrfs_key *key,
 			   struct btrfs_chunk *chunk, int item_size)
 {
@@ -3221,7 +3217,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 		if (total_avail == 0)
 			continue;
 
-		ret = find_free_dev_extent(trans, device,
+		ret = find_free_dev_extent(device,
 					   max_stripe_size * dev_stripes,
 					   &dev_offset, &max_avail);
 		if (ret && ret != -ENOSPC)
@@ -3412,7 +3408,7 @@ static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
 	BUG_ON(ret);
 
 	if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
-		ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
+		ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
 					     item_size);
 		BUG_ON(ret);
 	}
@@ -3624,26 +3620,13 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 	u64 stripe_nr;
 	u64 stripe_nr_orig;
 	u64 stripe_nr_end;
-	int stripes_allocated = 8;
-	int stripes_required = 1;
 	int stripe_index;
 	int i;
+	int ret = 0;
 	int num_stripes;
 	int max_errors = 0;
 	struct btrfs_bio *bbio = NULL;
 
-	if (bbio_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
-		stripes_allocated = 1;
-again:
-	if (bbio_ret) {
-		bbio = kzalloc(btrfs_bio_size(stripes_allocated),
-				GFP_NOFS);
-		if (!bbio)
-			return -ENOMEM;
-
-		atomic_set(&bbio->error, 0);
-	}
-
 	read_lock(&em_tree->lock);
 	em = lookup_extent_mapping(em_tree, logical, *length);
 	read_unlock(&em_tree->lock);
@@ -3662,28 +3645,6 @@ again:
 	if (mirror_num > map->num_stripes)
 		mirror_num = 0;
 
-	/* if our btrfs_bio struct is too small, back off and try again */
-	if (rw & REQ_WRITE) {
-		if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
-				 BTRFS_BLOCK_GROUP_DUP)) {
-			stripes_required = map->num_stripes;
-			max_errors = 1;
-		} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
-			stripes_required = map->sub_stripes;
-			max_errors = 1;
-		}
-	}
-	if (rw & REQ_DISCARD) {
-		if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK)
-			stripes_required = map->num_stripes;
-	}
-	if (bbio_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
-	    stripes_allocated < stripes_required) {
-		stripes_allocated = map->num_stripes;
-		free_extent_map(em);
-		kfree(bbio);
-		goto again;
-	}
 	stripe_nr = offset;
 	/*
 	 * stripe_nr counts the total number of stripes we have to stride
@@ -3775,81 +3736,55 @@ again:
 	}
 	BUG_ON(stripe_index >= map->num_stripes);
 
+	bbio = kzalloc(btrfs_bio_size(num_stripes), GFP_NOFS);
+	if (!bbio) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	atomic_set(&bbio->error, 0);
+
 	if (rw & REQ_DISCARD) {
+		int factor = 0;
+		int sub_stripes = 0;
+		u64 stripes_per_dev = 0;
+		u32 remaining_stripes = 0;
+
+		if (map->type &
+		    (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
+			if (map->type & BTRFS_BLOCK_GROUP_RAID0)
+				sub_stripes = 1;
+			else
+				sub_stripes = map->sub_stripes;
+
+			factor = map->num_stripes / sub_stripes;
+			stripes_per_dev = div_u64_rem(stripe_nr_end -
+						      stripe_nr_orig,
+						      factor,
+						      &remaining_stripes);
+		}
+
 		for (i = 0; i < num_stripes; i++) {
 			bbio->stripes[i].physical =
 				map->stripes[stripe_index].physical +
 				stripe_offset + stripe_nr * map->stripe_len;
 			bbio->stripes[i].dev = map->stripes[stripe_index].dev;
 
-			if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
-				u64 stripes;
-				u32 last_stripe = 0;
-				int j;
-
-				div_u64_rem(stripe_nr_end - 1,
-					    map->num_stripes,
-					    &last_stripe);
-
-				for (j = 0; j < map->num_stripes; j++) {
-					u32 test;
-
-					div_u64_rem(stripe_nr_end - 1 - j,
-						    map->num_stripes, &test);
-					if (test == stripe_index)
-						break;
-				}
-				stripes = stripe_nr_end - 1 - j;
-				do_div(stripes, map->num_stripes);
-				bbio->stripes[i].length = map->stripe_len *
-					(stripes - stripe_nr + 1);
-
-				if (i == 0) {
-					bbio->stripes[i].length -=
-						stripe_offset;
-					stripe_offset = 0;
-				}
-				if (stripe_index == last_stripe)
-					bbio->stripes[i].length -=
-						stripe_end_offset;
-			} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
-				u64 stripes;
-				int j;
-				int factor = map->num_stripes /
-					     map->sub_stripes;
-				u32 last_stripe = 0;
-
-				div_u64_rem(stripe_nr_end - 1,
-					    factor, &last_stripe);
-				last_stripe *= map->sub_stripes;
-
-				for (j = 0; j < factor; j++) {
-					u32 test;
-
-					div_u64_rem(stripe_nr_end - 1 - j,
-						    factor, &test);
-
-					if (test ==
-					    stripe_index / map->sub_stripes)
-						break;
-				}
-				stripes = stripe_nr_end - 1 - j;
-				do_div(stripes, factor);
-				bbio->stripes[i].length = map->stripe_len *
-					(stripes - stripe_nr + 1);
-
-				if (i < map->sub_stripes) {
+			if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
+					 BTRFS_BLOCK_GROUP_RAID10)) {
+				bbio->stripes[i].length = stripes_per_dev *
+							  map->stripe_len;
+				if (i / sub_stripes < remaining_stripes)
+					bbio->stripes[i].length +=
+						map->stripe_len;
+				if (i < sub_stripes)
 					bbio->stripes[i].length -=
 						stripe_offset;
-					if (i == map->sub_stripes - 1)
-						stripe_offset = 0;
-				}
-				if (stripe_index >= last_stripe &&
-				    stripe_index <= (last_stripe +
-						     map->sub_stripes - 1)) {
+				if ((i / sub_stripes + 1) %
+				    sub_stripes == remaining_stripes)
 					bbio->stripes[i].length -=
 						stripe_end_offset;
-				}
+				if (i == sub_stripes - 1)
+					stripe_offset = 0;
 			} else
 				bbio->stripes[i].length = *length;
 
@@ -3871,15 +3806,22 @@ again:
 			stripe_index++;
 		}
 	}
-	if (bbio_ret) {
-		*bbio_ret = bbio;
-		bbio->num_stripes = num_stripes;
-		bbio->max_errors = max_errors;
-		bbio->mirror_num = mirror_num;
+
+	if (rw & REQ_WRITE) {
+		if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
+				 BTRFS_BLOCK_GROUP_RAID10 |
+				 BTRFS_BLOCK_GROUP_DUP)) {
+			max_errors = 1;
+		}
 	}
+
+	*bbio_ret = bbio;
+	bbio->num_stripes = num_stripes;
+	bbio->max_errors = max_errors;
+	bbio->mirror_num = mirror_num;
 out:
 	free_extent_map(em);
-	return 0;
+	return ret;
 }
 
 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
@@ -4284,7 +4226,7 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
 	struct btrfs_fs_devices *fs_devices;
 	int ret;
 
-	mutex_lock(&uuid_mutex);
+	BUG_ON(!mutex_is_locked(&uuid_mutex));
 
 	fs_devices = root->fs_info->fs_devices->seed;
 	while (fs_devices) {
@@ -4322,7 +4264,6 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
 	fs_devices->seed = root->fs_info->fs_devices->seed;
 	root->fs_info->fs_devices->seed = fs_devices;
 out:
-	mutex_unlock(&uuid_mutex);
 	return ret;
 }
 
@@ -4465,6 +4406,9 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
 	if (!path)
 		return -ENOMEM;
 
+	mutex_lock(&uuid_mutex);
+	lock_chunks(root);
+
 	/* first we search for all of the device items, and then we
 	 * read in all of the chunk items.  This way we can create chunk
 	 * mappings that reference all of the devices that are afound
@@ -4515,6 +4459,9 @@ again:
 	}
 	ret = 0;
 error:
+	unlock_chunks(root);
+	mutex_unlock(&uuid_mutex);
+
 	btrfs_free_path(path);
 	return ret;
 }
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 6faec9dd1f93..19ac95048b88 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -279,7 +279,6 @@ int btrfs_recover_balance(struct btrfs_root *tree_root);
 int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);
-int find_free_dev_extent(struct btrfs_trans_handle *trans,
-			 struct btrfs_device *device, u64 num_bytes,
+int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 			 u64 *start, u64 *max_avail);
 #endif