Btrfs: Replace the big fs_mutex with a collection of other locks

Extent alloctions are still protected by a large alloc_mutex.
Objectid allocations are covered by a objectid mutex
Other btree operations are protected by a lock on individual btree nodes

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

12 files changed, 101 insertions, 165 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 75625c68fdd8..dff4da082d06 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -63,6 +63,9 @@ void btrfs_free_path(struct btrfs_path *p)
 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
 {
         int i;
+        int skip = p->skip_locking;
+        int keep = p->keep_locks;
+
         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
                 if (!p->nodes[i])
                         continue;
@@ -73,6 +76,8 @@ void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
                 free_extent_buffer(p->nodes[i]);
         }
         memset(p, 0, sizeof(*p));
+        p->skip_locking = skip;
+        p->keep_locks = keep;
 }
 
 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
@@ -1202,13 +1207,19 @@ static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
                         u32 nritems;
                         t = path->nodes[i];
                         nritems = btrfs_header_nritems(t);
-                        if (path->slots[i] >= nritems - 1) {
+                        if (nritems < 2 || path->slots[i] >= nritems - 2) {
+if (path->keep_locks) {
+//printk("path %p skip level now %d\n", path, skip_level);
+}
                                 skip_level = i + 1;
                                 continue;
                         }
                 }
                 t = path->nodes[i];
                 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
+if (path->keep_locks) {
+//printk("path %p unlocking level %d slot %d nritems %d skip_level %d\n", path, i, path->slots[i], btrfs_header_nritems(t), skip_level);
+}
                         btrfs_tree_unlock(t);
                         path->locks[i] = 0;
                 }
@@ -1243,7 +1254,6 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
         lowest_level = p->lowest_level;
         WARN_ON(lowest_level && ins_len);
         WARN_ON(p->nodes[0] != NULL);
-        // WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
         WARN_ON(root == root->fs_info->extent_root &&
                 !mutex_is_locked(&root->fs_info->alloc_mutex));
         WARN_ON(root == root->fs_info->chunk_root &&
@@ -1321,7 +1331,7 @@ again:
                         b = read_node_slot(root, b, slot);
                         if (!p->skip_locking)
                                 btrfs_tree_lock(b);
-                        unlock_up(p, level, lowest_unlock);
+                        unlock_up(p, level + 1, lowest_unlock);
                 } else {
                         p->slots[level] = slot;
                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
@@ -1804,6 +1814,8 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
         if (slot >= btrfs_header_nritems(upper) - 1)
                 return 1;
 
+        WARN_ON(!btrfs_tree_locked(path->nodes[1]));
+
         right = read_node_slot(root, upper, slot + 1);
         btrfs_tree_lock(right);
         free_space = btrfs_leaf_free_space(root, right);
@@ -1981,6 +1993,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                 return 1;
         }
 
+        WARN_ON(!btrfs_tree_locked(path->nodes[1]));
+
         left = read_node_slot(root, path->nodes[1], slot - 1);
         btrfs_tree_lock(left);
         free_space = btrfs_leaf_free_space(root, left);
@@ -2957,15 +2971,16 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
 
         btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
 
-        path->keep_locks = 1;
         btrfs_release_path(root, path);
+        path->keep_locks = 1;
         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
         path->keep_locks = 0;
 
         if (ret < 0)
                 return ret;
 
-        if (path->slots[0] < nritems - 1) {
+        nritems = btrfs_header_nritems(path->nodes[0]);
+        if (nritems > 0 && path->slots[0] < nritems - 1) {
                 goto done;
         }
 
@@ -2992,8 +3007,17 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
                         reada_for_search(root, path, level, slot, 0);
 
                 next = read_node_slot(root, c, slot);
-                if (!path->skip_locking)
+                if (!path->skip_locking) {
+                        if (!btrfs_tree_locked(c)) {
+                                int i;
+                                WARN_ON(1);
+printk("path %p no lock on level %d\n", path, level);
+for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
+printk("path %p level %d slot %d nritems %d\n", path, i, path->slots[i], btrfs_header_nritems(path->nodes[i]));
+}
+                        }
                         btrfs_tree_lock(next);
+                }
                 break;
         }
         path->slots[level] = slot;
@@ -3011,8 +3035,10 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
                 if (level == 1 && path->locks[1] && path->reada)
                         reada_for_search(root, path, level, slot, 0);
                 next = read_node_slot(root, next, 0);
-                if (!path->skip_locking)
+                if (!path->skip_locking) {
+                        WARN_ON(!btrfs_tree_locked(path->nodes[level]));
                         btrfs_tree_lock(next);
+                }
         }
 done:
         unlock_up(path, 0, 1);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 50891b39f366..692b8ea42de1 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -519,9 +519,9 @@ struct btrfs_fs_info {
         struct backing_dev_info bdi;
         spinlock_t hash_lock;
         struct mutex trans_mutex;
-        struct mutex fs_mutex;
         struct mutex alloc_mutex;
         struct mutex chunk_mutex;
+        struct mutex drop_mutex;
         struct list_head trans_list;
         struct list_head hashers;
         struct list_head dead_roots;
@@ -554,7 +554,7 @@ struct btrfs_fs_info {
         struct completion kobj_unregister;
         int do_barriers;
         int closing;
-        unsigned long throttles;
+        atomic_t throttles;
 
         u64 total_pinned;
         struct list_head dirty_cowonly_roots;
@@ -594,6 +594,7 @@ struct btrfs_root {
         struct inode *inode;
         struct kobject root_kobj;
         struct completion kobj_unregister;
+        struct mutex objectid_mutex;
         u64 objectid;
         u64 last_trans;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fe40bdd984ff..f638803549e0 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -724,6 +724,7 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 
         INIT_LIST_HEAD(&root->dirty_list);
         spin_lock_init(&root->node_lock);
+        mutex_init(&root->objectid_mutex);
         memset(&root->root_key, 0, sizeof(root->root_key));
         memset(&root->root_item, 0, sizeof(root->root_item));
         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
@@ -1146,6 +1147,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         INIT_LIST_HEAD(&fs_info->space_info);
         btrfs_mapping_init(&fs_info->mapping_tree);
         atomic_set(&fs_info->nr_async_submits, 0);
+        atomic_set(&fs_info->throttles, 0);
         fs_info->sb = sb;
         fs_info->max_extent = (u64)-1;
         fs_info->max_inline = 8192 * 1024;
@@ -1199,7 +1201,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
 
         mutex_init(&fs_info->trans_mutex);
-        mutex_init(&fs_info->fs_mutex);
+        mutex_init(&fs_info->drop_mutex);
         mutex_init(&fs_info->alloc_mutex);
         mutex_init(&fs_info->chunk_mutex);
 
@@ -1278,8 +1280,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
                 goto fail_sb_buffer;
         }
 
-        mutex_lock(&fs_info->fs_mutex);
-
         mutex_lock(&fs_info->chunk_mutex);
         ret = btrfs_read_sys_array(tree_root);
         mutex_unlock(&fs_info->chunk_mutex);
@@ -1342,7 +1342,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         fs_info->metadata_alloc_profile = (u64)-1;
         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
 
-        mutex_unlock(&fs_info->fs_mutex);
         return tree_root;
 
 fail_extent_root:
@@ -1350,7 +1349,6 @@ fail_extent_root:
 fail_tree_root:
         free_extent_buffer(tree_root->node);
 fail_sys_array:
-        mutex_unlock(&fs_info->fs_mutex);
 fail_sb_buffer:
         extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
         btrfs_stop_workers(&fs_info->workers);
@@ -1562,8 +1560,9 @@ int close_ctree(struct btrfs_root *root)
         struct btrfs_fs_info *fs_info = root->fs_info;
 
         fs_info->closing = 1;
+        smp_mb();
+
         btrfs_transaction_flush_work(root);
-        mutex_lock(&fs_info->fs_mutex);
         btrfs_defrag_dirty_roots(root->fs_info);
         trans = btrfs_start_transaction(root, 1);
         ret = btrfs_commit_transaction(trans, root);
@@ -1574,7 +1573,6 @@ int close_ctree(struct btrfs_root *root)
         BUG_ON(ret);
 
         write_ctree_super(NULL, root);
-        mutex_unlock(&fs_info->fs_mutex);
 
         btrfs_transaction_flush_work(root);
 
@@ -1679,7 +1677,8 @@ void btrfs_throttle(struct btrfs_root *root)
         struct backing_dev_info *bdi;
 
         bdi = &root->fs_info->bdi;
-        if (root->fs_info->throttles && bdi_write_congested(bdi)) {
+        if (atomic_read(&root->fs_info->throttles) &&
+            bdi_write_congested(bdi)) {
 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18)
                 congestion_wait(WRITE, HZ/20);
 #else
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7e40c516fe62..890b9e9d8e27 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1577,9 +1577,11 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                 }
 
                 /* block accounting for super block */
+                spin_lock_irq(&info->delalloc_lock);
                 super_used = btrfs_super_bytes_used(&info->super_copy);
                 btrfs_set_super_bytes_used(&info->super_copy,
                                            super_used - num_bytes);
+                spin_unlock_irq(&info->delalloc_lock);
 
                 /* block accounting for root item */
                 root_used = btrfs_root_used(&root->root_item);
@@ -1968,8 +1970,10 @@ again:
         }
 
         /* block accounting for super block */
+        spin_lock_irq(&info->delalloc_lock);
         super_used = btrfs_super_bytes_used(&info->super_copy);
         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
+        spin_unlock_irq(&info->delalloc_lock);
 
         /* block accounting for root item */
         root_used = btrfs_root_used(&root->root_item);
@@ -2172,12 +2176,12 @@ static void noinline reada_walk_down(struct btrfs_root *root,
                                 continue;
                         }
                 }
-                mutex_unlock(&root->fs_info->fs_mutex);
+                mutex_unlock(&root->fs_info->alloc_mutex);
                 ret = readahead_tree_block(root, bytenr, blocksize,
                                            btrfs_node_ptr_generation(node, i));
                 last = bytenr + blocksize;
                 cond_resched();
-                mutex_lock(&root->fs_info->fs_mutex);
+                mutex_lock(&root->fs_info->alloc_mutex);
                 if (ret)
                         break;
         }
@@ -2254,11 +2258,9 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
                         free_extent_buffer(next);
                         reada_walk_down(root, cur, path->slots[*level]);
 
-                        mutex_unlock(&root->fs_info->fs_mutex);
                         mutex_unlock(&root->fs_info->alloc_mutex);
                         next = read_tree_block(root, bytenr, blocksize,
                                                ptr_gen);
-                        mutex_lock(&root->fs_info->fs_mutex);
                         mutex_lock(&root->fs_info->alloc_mutex);
 
                         /* we've dropped the lock, double check */
@@ -2381,6 +2383,7 @@ int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
         int orig_level;
         struct btrfs_root_item *root_item = &root->root_item;
 
+        WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
         path = btrfs_alloc_path();
         BUG_ON(!path);
 
@@ -2710,7 +2713,6 @@ static int noinline relocate_one_reference(struct btrfs_root *extent_root,
                     *last_file_root == ref_root)
                         goto out;
 
-                mutex_unlock(&extent_root->fs_info->fs_mutex);
                 inode = btrfs_iget_locked(extent_root->fs_info->sb,
                                           ref_objectid, found_root);
                 if (inode->i_state & I_NEW) {
@@ -2727,7 +2729,6 @@ static int noinline relocate_one_reference(struct btrfs_root *extent_root,
                  * the latest version of the tree root
                  */
                 if (is_bad_inode(inode)) {
-                        mutex_lock(&extent_root->fs_info->fs_mutex);
                         goto out;
                 }
                 *last_file_objectid = inode->i_ino;
@@ -2736,7 +2737,6 @@ static int noinline relocate_one_reference(struct btrfs_root *extent_root,
 
                 relocate_inode_pages(inode, ref_offset, extent_key->offset);
                 iput(inode);
-                mutex_lock(&extent_root->fs_info->fs_mutex);
         } else {
                 struct btrfs_trans_handle *trans;
                 struct extent_buffer *eb;
@@ -3033,9 +3033,7 @@ next:
 
                 if (progress && need_resched()) {
                         memcpy(&key, &found_key, sizeof(key));
-                        mutex_unlock(&root->fs_info->fs_mutex);
                         cond_resched();
-                        mutex_lock(&root->fs_info->fs_mutex);
                         btrfs_release_path(root, path);
                         btrfs_search_slot(NULL, root, &key, path, 0, 0);
                         progress = 0;
@@ -3068,9 +3066,7 @@ next:
                 trans = btrfs_start_transaction(tree_root, 1);
                 btrfs_commit_transaction(trans, tree_root);
 
-                mutex_unlock(&root->fs_info->fs_mutex);
                 btrfs_clean_old_snapshots(tree_root);
-                mutex_lock(&root->fs_info->fs_mutex);
 
                 trans = btrfs_start_transaction(tree_root, 1);
                 btrfs_commit_transaction(trans, tree_root);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 73c6d085bd90..18bbe108a0e6 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -252,7 +252,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
         end_of_last_block = start_pos + num_bytes - 1;
 
         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         if (!trans) {
                 err = -ENOMEM;
@@ -341,7 +340,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 failed:
         err = btrfs_end_transaction(trans, root);
 out_unlock:
-        mutex_unlock(&root->fs_info->fs_mutex);
         unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
         return err;
 }
@@ -905,9 +903,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 WARN_ON(num_pages > nrptrs);
                 memset(pages, 0, sizeof(pages));
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 ret = btrfs_check_free_space(root, write_bytes, 0);
-                mutex_unlock(&root->fs_info->fs_mutex);
                 if (ret)
                         goto out;
 
@@ -998,9 +994,9 @@ static int btrfs_sync_file(struct file *file,
          * check the transaction that last modified this inode
          * and see if its already been committed
          */
-        mutex_lock(&root->fs_info->fs_mutex);
         if (!BTRFS_I(inode)->last_trans)
                 goto out;
+
         mutex_lock(&root->fs_info->trans_mutex);
         if (BTRFS_I(inode)->last_trans <=
             root->fs_info->last_trans_committed) {
@@ -1023,7 +1019,6 @@ static int btrfs_sync_file(struct file *file,
         }
         ret = btrfs_commit_transaction(trans, root);
 out:
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret > 0 ? EIO : ret;
 }
 
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index a0925eabdaa2..298346ae1481 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -69,6 +69,12 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
         struct btrfs_key search_key;
         u64 search_start = dirid;
 
+        mutex_lock(&root->objectid_mutex);
+        if (root->last_inode_alloc) {
+                *objectid = ++root->last_inode_alloc;
+                mutex_unlock(&root->objectid_mutex);
+                return 0;
+        }
         path = btrfs_alloc_path();
         BUG_ON(!path);
         search_start = root->last_inode_alloc;
@@ -124,9 +130,11 @@ found:
         btrfs_release_path(root, path);
         btrfs_free_path(path);
         BUG_ON(*objectid < search_start);
+        mutex_unlock(&root->objectid_mutex);
         return 0;
 error:
         btrfs_release_path(root, path);
         btrfs_free_path(path);
+        mutex_unlock(&root->objectid_mutex);
         return ret;
 }
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 61bd8953a683..b2251e27ac84 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -79,12 +79,15 @@ static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
 int btrfs_check_free_space(struct btrfs_root *root, u64 num_required,
                            int for_del)
 {
-        u64 total = btrfs_super_total_bytes(&root->fs_info->super_copy);
-        u64 used = btrfs_super_bytes_used(&root->fs_info->super_copy);
+        u64 total;
+        u64 used;
         u64 thresh;
         unsigned long flags;
         int ret = 0;
 
+        spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
+        total = btrfs_super_total_bytes(&root->fs_info->super_copy);
+        used = btrfs_super_bytes_used(&root->fs_info->super_copy);
         if (for_del)
                 thresh = total * 90;
         else
@@ -92,7 +95,6 @@ int btrfs_check_free_space(struct btrfs_root *root, u64 num_required,
 
         do_div(thresh, 100);
 
-        spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
         if (used + root->fs_info->delalloc_bytes + num_required > thresh)
                 ret = -ENOSPC;
         spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);
@@ -115,7 +117,6 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end)
         trans = btrfs_start_transaction(root, 1);
         BUG_ON(!trans);
         btrfs_set_trans_block_group(trans, inode);
-        mutex_unlock(&root->fs_info->fs_mutex);
 
         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
         num_bytes = max(blocksize,  num_bytes);
@@ -160,7 +161,6 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end)
         btrfs_add_ordered_inode(inode);
         btrfs_update_inode(trans, root, inode);
 out:
-        mutex_lock(&root->fs_info->fs_mutex);
         btrfs_end_transaction(trans, root);
         return ret;
 }
@@ -269,14 +269,13 @@ static int run_delalloc_range(struct inode *inode, u64 start, u64 end)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         int ret;
-        mutex_lock(&root->fs_info->fs_mutex);
+
         if (btrfs_test_opt(root, NODATACOW) ||
             btrfs_test_flag(inode, NODATACOW))
                 ret = run_delalloc_nocow(inode, start, end);
         else
                 ret = cow_file_range(inode, start, end);
 
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
 
@@ -349,17 +348,13 @@ int __btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
         ret = btrfs_csum_one_bio(root, bio, &sums);
         BUG_ON(ret);
 
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
-        mutex_unlock(&root->fs_info->fs_mutex);
 
         btrfs_set_trans_block_group(trans, inode);
         btrfs_csum_file_blocks(trans, root, inode, bio, sums);
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_end_transaction(trans, root);
         BUG_ON(ret);
-        mutex_unlock(&root->fs_info->fs_mutex);
 
         kfree(sums);
 
@@ -404,7 +399,6 @@ int btrfs_readpage_io_hook(struct page *page, u64 start, u64 end)
             btrfs_test_flag(inode, NODATASUM))
                 return 0;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         path = btrfs_alloc_path();
         item = btrfs_lookup_csum(NULL, root, path, inode->i_ino, start, 0);
         if (IS_ERR(item)) {
@@ -422,7 +416,6 @@ int btrfs_readpage_io_hook(struct page *page, u64 start, u64 end)
 out:
         if (path)
                 btrfs_free_path(path);
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
 
@@ -616,7 +609,6 @@ void btrfs_read_locked_inode(struct inode *inode)
 
         path = btrfs_alloc_path();
         BUG_ON(!path);
-        mutex_lock(&root->fs_info->fs_mutex);
         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
 
         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
@@ -662,8 +654,6 @@ void btrfs_read_locked_inode(struct inode *inode)
         btrfs_free_path(path);
         inode_item = NULL;
 
-        mutex_unlock(&root->fs_info->fs_mutex);
-
         switch (inode->i_mode & S_IFMT) {
         case S_IFREG:
                 inode->i_mapping->a_ops = &btrfs_aops;
@@ -691,9 +681,7 @@ void btrfs_read_locked_inode(struct inode *inode)
         return;
 
 make_bad:
-        btrfs_release_path(root, path);
         btrfs_free_path(path);
-        mutex_unlock(&root->fs_info->fs_mutex);
         make_bad_inode(inode);
 }
 
@@ -758,7 +746,6 @@ int btrfs_update_inode(struct btrfs_trans_handle *trans,
         btrfs_set_inode_last_trans(trans, inode);
         ret = 0;
 failed:
-        btrfs_release_path(root, path);
         btrfs_free_path(path);
         return ret;
 }
@@ -849,7 +836,6 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
         unsigned long nr = 0;
 
         root = BTRFS_I(dir)->root;
-        mutex_lock(&root->fs_info->fs_mutex);
 
         ret = btrfs_check_free_space(root, 1, 1);
         if (ret)
@@ -871,7 +857,6 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
 
         btrfs_end_transaction(trans, root);
 fail:
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
         btrfs_throttle(root);
         return ret;
@@ -890,7 +875,6 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
                 return -ENOTEMPTY;
         }
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_check_free_space(root, 1, 1);
         if (ret)
                 goto fail;
@@ -907,7 +891,6 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
         nr = trans->blocks_used;
         ret = btrfs_end_transaction(trans, root);
 fail:
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
         btrfs_throttle(root);
 
@@ -1129,7 +1112,6 @@ error:
                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
                                       pending_del_nr);
         }
-        btrfs_release_path(root, path);
         btrfs_free_path(path);
         inode->i_sb->s_dirt = 1;
         return ret;
@@ -1234,9 +1216,7 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
                 if (attr->ia_size <= hole_start)
                         goto out;
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 err = btrfs_check_free_space(root, 1, 0);
-                mutex_unlock(&root->fs_info->fs_mutex);
                 if (err)
                         goto fail;
 
@@ -1245,7 +1225,6 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
                 lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
                 hole_size = block_end - hole_start;
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 trans = btrfs_start_transaction(root, 1);
                 btrfs_set_trans_block_group(trans, inode);
                 err = btrfs_drop_extents(trans, root, inode,
@@ -1262,7 +1241,6 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
                         btrfs_check_file(root, inode);
                 }
                 btrfs_end_transaction(trans, root);
-                mutex_unlock(&root->fs_info->fs_mutex);
                 unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
                 if (err)
                         return err;
@@ -1286,7 +1264,6 @@ void btrfs_delete_inode(struct inode *inode)
         }
 
         inode->i_size = 0;
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
 
         btrfs_set_trans_block_group(trans, inode);
@@ -1298,7 +1275,6 @@ void btrfs_delete_inode(struct inode *inode)
         clear_inode(inode);
 
         btrfs_end_transaction(trans, root);
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
         btrfs_throttle(root);
         return;
@@ -1306,7 +1282,6 @@ void btrfs_delete_inode(struct inode *inode)
 no_delete_lock:
         nr = trans->blocks_used;
         btrfs_end_transaction(trans, root);
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
         btrfs_throttle(root);
 no_delete:
@@ -1402,7 +1377,6 @@ static int fixup_tree_root_location(struct btrfs_root *root,
 
         path = btrfs_alloc_path();
         BUG_ON(!path);
-        mutex_lock(&root->fs_info->fs_mutex);
 
         *sub_root = btrfs_read_fs_root(root->fs_info, location,
                                         dentry->d_name.name,
@@ -1416,7 +1390,6 @@ static int fixup_tree_root_location(struct btrfs_root *root,
         location->offset = 0;
 
         btrfs_free_path(path);
-        mutex_unlock(&root->fs_info->fs_mutex);
         return 0;
 }
 
@@ -1482,9 +1455,7 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
         if (dentry->d_name.len > BTRFS_NAME_LEN)
                 return ERR_PTR(-ENAMETOOLONG);
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_inode_by_name(dir, dentry, &location);
-        mutex_unlock(&root->fs_info->fs_mutex);
 
         if (ret < 0)
                 return ERR_PTR(ret);
@@ -1559,7 +1530,6 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
                 filp->f_pos = 1;
         }
 
-        mutex_lock(&root->fs_info->fs_mutex);
         key.objectid = inode->i_ino;
         path = btrfs_alloc_path();
         path->reada = 2;
@@ -1668,9 +1638,7 @@ read_dir_items:
 nopos:
         ret = 0;
 err:
-        btrfs_release_path(root, path);
         btrfs_free_path(path);
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
 
@@ -1681,11 +1649,9 @@ int btrfs_write_inode(struct inode *inode, int wait)
         int ret = 0;
 
         if (wait) {
-                mutex_lock(&root->fs_info->fs_mutex);
                 trans = btrfs_start_transaction(root, 1);
                 btrfs_set_trans_block_group(trans, inode);
                 ret = btrfs_commit_transaction(trans, root);
-                mutex_unlock(&root->fs_info->fs_mutex);
         }
         return ret;
 }
@@ -1701,12 +1667,10 @@ void btrfs_dirty_inode(struct inode *inode)
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         btrfs_set_trans_block_group(trans, inode);
         btrfs_update_inode(trans, root, inode);
         btrfs_end_transaction(trans, root);
-        mutex_unlock(&root->fs_info->fs_mutex);
 }
 
 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
@@ -1874,7 +1838,6 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
         if (!new_valid_dev(rdev))
                 return -EINVAL;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         err = btrfs_check_free_space(root, 1, 0);
         if (err)
                 goto fail;
@@ -1912,8 +1875,6 @@ out_unlock:
         nr = trans->blocks_used;
         btrfs_end_transaction(trans, root);
 fail:
-        mutex_unlock(&root->fs_info->fs_mutex);
-
         if (drop_inode) {
                 inode_dec_link_count(inode);
                 iput(inode);
@@ -1934,7 +1895,6 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         unsigned long nr = 0;
         u64 objectid;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         err = btrfs_check_free_space(root, 1, 0);
         if (err)
                 goto fail;
@@ -1980,8 +1940,6 @@ out_unlock:
         nr = trans->blocks_used;
         btrfs_end_transaction(trans, root);
 fail:
-        mutex_unlock(&root->fs_info->fs_mutex);
-
         if (drop_inode) {
                 inode_dec_link_count(inode);
                 iput(inode);
@@ -2009,7 +1967,6 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 #else
         inc_nlink(inode);
 #endif
-        mutex_lock(&root->fs_info->fs_mutex);
         err = btrfs_check_free_space(root, 1, 0);
         if (err)
                 goto fail;
@@ -2032,8 +1989,6 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
         nr = trans->blocks_used;
         btrfs_end_transaction(trans, root);
 fail:
-        mutex_unlock(&root->fs_info->fs_mutex);
-
         if (drop_inode) {
                 inode_dec_link_count(inode);
                 iput(inode);
@@ -2053,7 +2008,6 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         u64 objectid = 0;
         unsigned long nr = 1;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         err = btrfs_check_free_space(root, 1, 0);
         if (err)
                 goto out_unlock;
@@ -2106,7 +2060,6 @@ out_fail:
         btrfs_end_transaction(trans, root);
 
 out_unlock:
-        mutex_unlock(&root->fs_info->fs_mutex);
         if (drop_on_err)
                 iput(inode);
         btrfs_btree_balance_dirty(root, nr);
@@ -2199,7 +2152,6 @@ struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
 
         path = btrfs_alloc_path();
         BUG_ON(!path);
-        mutex_lock(&root->fs_info->fs_mutex);
 
 again:
         spin_lock(&em_tree->lock);
@@ -2402,7 +2354,6 @@ out:
                 if (!err)
                         err = ret;
         }
-        mutex_unlock(&root->fs_info->fs_mutex);
         if (err) {
                 free_extent_map(em);
                 WARN_ON(1);
@@ -2584,9 +2535,7 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
         int ret;
         u64 page_start;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_check_free_space(root, PAGE_CACHE_SIZE, 0);
-        mutex_unlock(&root->fs_info->fs_mutex);
         if (ret)
                 goto out;
 
@@ -2631,7 +2580,6 @@ static void btrfs_truncate(struct inode *inode)
 
         btrfs_truncate_page(inode->i_mapping, inode->i_size);
 
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         btrfs_set_trans_block_group(trans, inode);
 
@@ -2643,7 +2591,6 @@ static void btrfs_truncate(struct inode *inode)
 
         ret = btrfs_end_transaction(trans, root);
         BUG_ON(ret);
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
         btrfs_throttle(root);
 }
@@ -2827,7 +2774,6 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
         struct inode *new_inode = new_dentry->d_inode;
         struct inode *old_inode = old_dentry->d_inode;
         struct timespec ctime = CURRENT_TIME;
-        struct btrfs_path *path;
         int ret;
 
         if (S_ISDIR(old_inode->i_mode) && new_inode &&
@@ -2835,7 +2781,6 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
                 return -ENOTEMPTY;
         }
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_check_free_space(root, 1, 0);
         if (ret)
                 goto out_unlock;
@@ -2843,11 +2788,6 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
         trans = btrfs_start_transaction(root, 1);
 
         btrfs_set_trans_block_group(trans, new_dir);
-        path = btrfs_alloc_path();
-        if (!path) {
-                ret = -ENOMEM;
-                goto out_fail;
-        }
 
         old_dentry->d_inode->i_nlink++;
         old_dir->i_ctime = old_dir->i_mtime = ctime;
@@ -2869,10 +2809,8 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
                 goto out_fail;
 
 out_fail:
-        btrfs_free_path(path);
         btrfs_end_transaction(trans, root);
 out_unlock:
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
 
@@ -2898,7 +2836,6 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
                 return -ENAMETOOLONG;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         err = btrfs_check_free_space(root, 1, 0);
         if (err)
                 goto out_fail;
@@ -2979,7 +2916,6 @@ out_unlock:
         nr = trans->blocks_used;
         btrfs_end_transaction(trans, root);
 out_fail:
-        mutex_unlock(&root->fs_info->fs_mutex);
         if (drop_inode) {
                 inode_dec_link_count(inode);
                 iput(inode);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3fbf74e93dba..6002eb64daf9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -63,7 +63,6 @@ static noinline int create_subvol(struct btrfs_root *root, char *name,
         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
         unsigned long nr = 1;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_check_free_space(root, 1, 0);
         if (ret)
                 goto fail_commit;
@@ -164,7 +163,6 @@ fail:
         if (err && !ret)
                 ret = err;
 fail_commit:
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
         btrfs_throttle(root);
         return ret;
@@ -181,7 +179,6 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
         if (!root->ref_cows)
                 return -EINVAL;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_check_free_space(root, 1, 0);
         if (ret)
                 goto fail_unlock;
@@ -208,7 +205,6 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
         err = btrfs_commit_transaction(trans, root);
 
 fail_unlock:
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
         btrfs_throttle(root);
         return ret;
@@ -228,9 +224,7 @@ int btrfs_defrag_file(struct file *file)
         unsigned long i;
         int ret;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         ret = btrfs_check_free_space(root, inode->i_size, 0);
-        mutex_unlock(&root->fs_info->fs_mutex);
         if (ret)
                 return -ENOSPC;
 
@@ -315,7 +309,8 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
                 goto out;
         }
 
-        mutex_lock(&root->fs_info->fs_mutex);
+        mutex_lock(&root->fs_info->alloc_mutex);
+        mutex_lock(&root->fs_info->chunk_mutex);
         sizestr = vol_args->name;
         devstr = strchr(sizestr, ':');
         if (devstr) {
@@ -385,7 +380,8 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
         }
 
 out_unlock:
-        mutex_unlock(&root->fs_info->fs_mutex);
+        mutex_lock(&root->fs_info->alloc_mutex);
+        mutex_lock(&root->fs_info->chunk_mutex);
 out:
         kfree(vol_args);
         return ret;
@@ -428,11 +424,9 @@ static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
         }
 
         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
-        mutex_lock(&root->fs_info->fs_mutex);
         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
                             path, root_dirid,
                             vol_args->name, namelen, 0);
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_free_path(path);
 
         if (di && !IS_ERR(di)) {
@@ -445,10 +439,12 @@ static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
                 goto out;
         }
 
+        mutex_lock(&root->fs_info->drop_mutex);
         if (root == root->fs_info->tree_root)
                 ret = create_subvol(root, vol_args->name, namelen);
         else
                 ret = create_snapshot(root, vol_args->name, namelen);
+        mutex_unlock(&root->fs_info->drop_mutex);
 out:
         kfree(vol_args);
         return ret;
@@ -461,10 +457,8 @@ static int btrfs_ioctl_defrag(struct file *file)
 
         switch (inode->i_mode & S_IFMT) {
         case S_IFDIR:
-                mutex_lock(&root->fs_info->fs_mutex);
                 btrfs_defrag_root(root, 0);
                 btrfs_defrag_root(root->fs_info->extent_root, 0);
-                mutex_unlock(&root->fs_info->fs_mutex);
                 break;
         case S_IFREG:
                 btrfs_defrag_file(file);
@@ -588,7 +582,6 @@ long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
         }
 
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 0);
         path = btrfs_alloc_path();
         if (!path) {
@@ -685,7 +678,6 @@ out:
         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 
         btrfs_end_transaction(trans, root);
-        mutex_unlock(&root->fs_info->fs_mutex);
 
 out_unlock:
         mutex_unlock(&src->i_mutex);
@@ -711,7 +703,6 @@ long btrfs_ioctl_trans_start(struct file *file)
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         if (file->private_data) {
                 ret = -EINPROGRESS;
                 goto out;
@@ -723,7 +714,6 @@ long btrfs_ioctl_trans_start(struct file *file)
                 ret = -ENOMEM;
         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
 out:
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
 
@@ -740,7 +730,6 @@ long btrfs_ioctl_trans_end(struct file *file)
         struct btrfs_trans_handle *trans;
         int ret = 0;
 
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = file->private_data;
         if (!trans) {
                 ret = -EINVAL;
@@ -749,7 +738,6 @@ long btrfs_ioctl_trans_end(struct file *file)
         btrfs_end_transaction(trans, root);
         file->private_data = 0;
 out:
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 196d0e280b19..b61ded7a20c9 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -366,12 +366,10 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
                 return 0;
         }
         btrfs_clean_old_snapshots(root);
-        mutex_lock(&root->fs_info->fs_mutex);
         btrfs_defrag_dirty_roots(root->fs_info);
         trans = btrfs_start_transaction(root, 1);
         ret = btrfs_commit_transaction(trans, root);
         sb->s_dirt = 0;
-        mutex_unlock(&root->fs_info->fs_mutex);
         return ret;
 }
 
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 1ed433a71493..5a1ee0665ae8 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -370,6 +370,7 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
         struct btrfs_trans_handle *trans;
         unsigned long nr;
 
+        smp_mb();
         if (root->defrag_running)
                 return 0;
         trans = btrfs_start_transaction(root, 1);
@@ -378,16 +379,15 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
                 nr = trans->blocks_used;
                 btrfs_end_transaction(trans, root);
-                mutex_unlock(&info->fs_mutex);
                 btrfs_btree_balance_dirty(info->tree_root, nr);
                 cond_resched();
 
-                mutex_lock(&info->fs_mutex);
                 trans = btrfs_start_transaction(root, 1);
                 if (ret != -EAGAIN)
                         break;
         }
         root->defrag_running = 0;
+        smp_mb();
         radix_tree_tag_clear(&info->fs_roots_radix,
                      (unsigned long)root->root_key.objectid,
                      BTRFS_ROOT_DEFRAG_TAG);
@@ -435,14 +435,14 @@ static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
         while(!list_empty(list)) {
                 struct btrfs_root *root;
 
-                mutex_lock(&tree_root->fs_info->fs_mutex);
                 dirty = list_entry(list->next, struct dirty_root, list);
                 list_del_init(&dirty->list);
 
                 num_bytes = btrfs_root_used(&dirty->root->root_item);
                 root = dirty->latest_root;
-                root->fs_info->throttles++;
+                atomic_inc(&root->fs_info->throttles);
 
+                mutex_lock(&root->fs_info->drop_mutex);
                 while(1) {
                         trans = btrfs_start_transaction(tree_root, 1);
                         ret = btrfs_drop_snapshot(trans, dirty->root);
@@ -459,14 +459,16 @@ static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
                         nr = trans->blocks_used;
                         ret = btrfs_end_transaction(trans, tree_root);
                         BUG_ON(ret);
-                        mutex_unlock(&tree_root->fs_info->fs_mutex);
+
+                        mutex_unlock(&root->fs_info->drop_mutex);
                         btrfs_btree_balance_dirty(tree_root, nr);
                         cond_resched();
-                        mutex_lock(&tree_root->fs_info->fs_mutex);
+                        mutex_lock(&root->fs_info->drop_mutex);
                 }
                 BUG_ON(ret);
-                root->fs_info->throttles--;
+                atomic_dec(&root->fs_info->throttles);
 
+                mutex_lock(&root->fs_info->alloc_mutex);
                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
                 bytes_used = btrfs_root_used(&root->root_item);
                 if (num_bytes) {
@@ -474,11 +476,15 @@ static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
                         btrfs_set_root_used(&root->root_item,
                                             bytes_used - num_bytes);
                 }
+                mutex_unlock(&root->fs_info->alloc_mutex);
+
                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
                 if (ret) {
                         BUG();
                         break;
                 }
+                mutex_unlock(&root->fs_info->drop_mutex);
+
                 nr = trans->blocks_used;
                 ret = btrfs_end_transaction(trans, tree_root);
                 BUG_ON(ret);
@@ -486,7 +492,6 @@ static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
                 free_extent_buffer(dirty->root->node);
                 kfree(dirty->root);
                 kfree(dirty);
-                mutex_unlock(&tree_root->fs_info->fs_mutex);
 
                 btrfs_btree_balance_dirty(tree_root, nr);
                 cond_resched();
@@ -503,7 +508,7 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
         u64 objectid = 0;
         int ret;
 
-        root->fs_info->throttles++;
+        atomic_inc(&root->fs_info->throttles);
         while(1) {
                 ret = btrfs_find_first_ordered_inode(
                                 &cur_trans->ordered_inode_tree,
@@ -512,7 +517,6 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
                         break;
 
                 mutex_unlock(&root->fs_info->trans_mutex);
-                mutex_unlock(&root->fs_info->fs_mutex);
 
                 if (S_ISREG(inode->i_mode)) {
                         atomic_inc(&BTRFS_I(inode)->ordered_writeback);
@@ -521,7 +525,6 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
                 }
                 iput(inode);
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 mutex_lock(&root->fs_info->trans_mutex);
         }
         while(1) {
@@ -533,7 +536,6 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
                 if (!ret)
                         break;
                 mutex_unlock(&root->fs_info->trans_mutex);
-                mutex_unlock(&root->fs_info->fs_mutex);
 
                 if (S_ISREG(inode->i_mode)) {
                         atomic_inc(&BTRFS_I(inode)->ordered_writeback);
@@ -543,10 +545,9 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
                 atomic_dec(&inode->i_count);
                 iput(inode);
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 mutex_lock(&root->fs_info->trans_mutex);
         }
-        root->fs_info->throttles--;
+        atomic_dec(&root->fs_info->throttles);
         return 0;
 }
 
@@ -661,7 +662,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 mutex_unlock(&root->fs_info->trans_mutex);
                 btrfs_end_transaction(trans, root);
 
-                mutex_unlock(&root->fs_info->fs_mutex);
                 ret = wait_for_commit(root, cur_trans);
                 BUG_ON(ret);
 
@@ -669,7 +669,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 put_transaction(cur_trans);
                 mutex_unlock(&root->fs_info->trans_mutex);
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 return 0;
         }
 
@@ -687,12 +686,10 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                                         struct btrfs_transaction, list);
                 if (!prev_trans->commit_done) {
                         prev_trans->use_count++;
-                        mutex_unlock(&root->fs_info->fs_mutex);
                         mutex_unlock(&root->fs_info->trans_mutex);
 
                         wait_for_commit(root, prev_trans);
 
-                        mutex_lock(&root->fs_info->fs_mutex);
                         mutex_lock(&root->fs_info->trans_mutex);
                         put_transaction(prev_trans);
                 }
@@ -709,12 +706,10 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 else
                         timeout = 1;
 
-                mutex_unlock(&root->fs_info->fs_mutex);
                 mutex_unlock(&root->fs_info->trans_mutex);
 
                 schedule_timeout(timeout);
 
-                mutex_lock(&root->fs_info->fs_mutex);
                 mutex_lock(&root->fs_info->trans_mutex);
                 finish_wait(&cur_trans->writer_wait, &wait);
                 ret = btrfs_write_ordered_inodes(trans, root);
@@ -755,12 +750,10 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         btrfs_copy_pinned(root, pinned_copy);
 
         mutex_unlock(&root->fs_info->trans_mutex);
-        mutex_unlock(&root->fs_info->fs_mutex);
         ret = btrfs_write_and_wait_transaction(trans, root);
         BUG_ON(ret);
         write_ctree_super(trans, root);
 
-        mutex_lock(&root->fs_info->fs_mutex);
         btrfs_finish_extent_commit(trans, root, pinned_copy);
         mutex_lock(&root->fs_info->trans_mutex);
 
@@ -781,9 +774,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 
         if (root->fs_info->closing) {
-                mutex_unlock(&root->fs_info->fs_mutex);
                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
-                mutex_lock(&root->fs_info->fs_mutex);
         }
         return ret;
 }
@@ -823,7 +814,7 @@ void btrfs_transaction_cleaner(struct work_struct *work)
         unsigned long delay = HZ * 30;
         int ret;
 
-        mutex_lock(&root->fs_info->fs_mutex);
+        smp_mb();
         if (root->fs_info->closing)
                 goto out;
 
@@ -844,7 +835,6 @@ void btrfs_transaction_cleaner(struct work_struct *work)
         trans = btrfs_start_transaction(root, 1);
         ret = btrfs_commit_transaction(trans, root);
 out:
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_clean_old_snapshots(root);
         btrfs_transaction_queue_work(root, delay);
 }
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ba3968571024..869864ddcc29 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -866,7 +866,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
         u64 devid;
         int ret = 0;
 
-        mutex_lock(&root->fs_info->fs_mutex);
+        mutex_lock(&root->fs_info->alloc_mutex);
+        mutex_lock(&root->fs_info->chunk_mutex);
         mutex_lock(&uuid_mutex);
 
         all_avail = root->fs_info->avail_data_alloc_bits |
@@ -984,7 +985,8 @@ error_close:
                 close_bdev_excl(bdev);
 out:
         mutex_unlock(&uuid_mutex);
-        mutex_unlock(&root->fs_info->fs_mutex);
+        mutex_unlock(&root->fs_info->chunk_mutex);
+        mutex_unlock(&root->fs_info->alloc_mutex);
         return ret;
 }
 
@@ -1003,7 +1005,10 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         if (!bdev) {
                 return -EIO;
         }
-        mutex_lock(&root->fs_info->fs_mutex);
+
+        mutex_lock(&root->fs_info->alloc_mutex);
+        mutex_lock(&root->fs_info->chunk_mutex);
+
         trans = btrfs_start_transaction(root, 1);
         devices = &root->fs_info->fs_devices->devices;
         list_for_each(cur, devices) {
@@ -1057,7 +1062,9 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         root->fs_info->fs_devices->open_devices++;
 out:
         btrfs_end_transaction(trans, root);
-        mutex_unlock(&root->fs_info->fs_mutex);
+        mutex_unlock(&root->fs_info->chunk_mutex);
+        mutex_unlock(&root->fs_info->alloc_mutex);
+
         return ret;
 
 out_close_bdev:
@@ -1297,9 +1304,10 @@ int btrfs_balance(struct btrfs_root *dev_root)
         struct btrfs_key found_key;
 
 
+        BUG(); /* FIXME, needs locking */
+
         dev_root = dev_root->fs_info->dev_root;
 
-        mutex_lock(&dev_root->fs_info->fs_mutex);
         /* step one make some room on all the devices */
         list_for_each(cur, devices) {
                 device = list_entry(cur, struct btrfs_device, dev_list);
@@ -1368,7 +1376,6 @@ int btrfs_balance(struct btrfs_root *dev_root)
         ret = 0;
 error:
         btrfs_free_path(path);
-        mutex_unlock(&dev_root->fs_info->fs_mutex);
         return ret;
 }
 
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index f63488dc2f16..3e9eb91c3c89 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -153,7 +153,6 @@ ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
                 return -ENOMEM;
         }
 
-        mutex_lock(&root->fs_info->fs_mutex);
         /* lookup the xattr by name */
         di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
                                 strlen(name), 0);
@@ -181,7 +180,6 @@ ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
         ret = btrfs_dir_data_len(leaf, di);
 
 out:
-        mutex_unlock(&root->fs_info->fs_mutex);
         kfree(name);
         btrfs_free_path(path);
         return ret;
@@ -210,7 +208,6 @@ int btrfs_xattr_set(struct inode *inode, int name_index,
                 return -ENOMEM;
         }
 
-        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         btrfs_set_trans_block_group(trans, inode);
 
@@ -260,7 +257,6 @@ out:
         }
 
         btrfs_end_transaction(trans, root);
-        mutex_unlock(&root->fs_info->fs_mutex);
         kfree(name);
         btrfs_free_path(path);
 
@@ -297,8 +293,6 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
                 return -ENOMEM;
         path->reada = 2;
 
-        mutex_lock(&root->fs_info->fs_mutex);
-
         /* search for our xattrs */
         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
         if (ret < 0)
@@ -379,15 +373,13 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
         ret = total_size;
 
 err:
-        mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_free_path(path);
 
         return ret;
 }
 
 /*
- * delete all the xattrs associated with the inode.  fs_mutex should be
- * held when we come into here
+ * delete all the xattrs associated with the inode.
  */
 int btrfs_delete_xattrs(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root, struct inode *inode)