Btrfs: fix data space leak fix
[deliverable/linux.git] / fs / btrfs / inode.c
index 81ba6654c3326dd38ba42944d8c121959b24b892..3a6f953337b51eb7068ae7e0f1489a582b9b054e 100644 (file)
@@ -1159,6 +1159,83 @@ static int run_delalloc_range(struct inode *inode, struct page *locked_page,
        return ret;
 }
 
+static int btrfs_split_extent_hook(struct inode *inode,
+                                   struct extent_state *orig, u64 split)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       u64 size;
+
+       if (!(orig->state & EXTENT_DELALLOC))
+               return 0;
+
+       size = orig->end - orig->start + 1;
+       if (size > root->fs_info->max_extent) {
+               u64 num_extents;
+               u64 new_size;
+
+               new_size = orig->end - split + 1;
+               num_extents = div64_u64(size + root->fs_info->max_extent - 1,
+                                       root->fs_info->max_extent);
+
+               /*
+                * if we break a large extent up then leave delalloc_extents be,
+                * since we've already accounted for the large extent.
+                */
+               if (div64_u64(new_size + root->fs_info->max_extent - 1,
+                             root->fs_info->max_extent) < num_extents)
+                       return 0;
+       }
+
+       BTRFS_I(inode)->delalloc_extents++;
+
+       return 0;
+}
+
+/*
+ * extent_io.c merge_extent_hook, used to track merged delayed allocation
+ * extents so we can keep track of new extents that are just merged onto old
+ * extents, such as when we are doing sequential writes, so we can properly
+ * account for the metadata space we'll need.
+ */
+static int btrfs_merge_extent_hook(struct inode *inode,
+                                  struct extent_state *new,
+                                  struct extent_state *other)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       u64 new_size, old_size;
+       u64 num_extents;
+
+       /* not delalloc, ignore it */
+       if (!(other->state & EXTENT_DELALLOC))
+               return 0;
+
+       old_size = other->end - other->start + 1;
+       if (new->start < other->start)
+               new_size = other->end - new->start + 1;
+       else
+               new_size = new->end - other->start + 1;
+
+       /* we're not bigger than the max, unreserve the space and go */
+       if (new_size <= root->fs_info->max_extent) {
+               BTRFS_I(inode)->delalloc_extents--;
+               return 0;
+       }
+
+       /*
+        * If we grew by another max_extent, just return, we want to keep that
+        * reserved amount.
+        */
+       num_extents = div64_u64(old_size + root->fs_info->max_extent - 1,
+                               root->fs_info->max_extent);
+       if (div64_u64(new_size + root->fs_info->max_extent - 1,
+                     root->fs_info->max_extent) > num_extents)
+               return 0;
+
+       BTRFS_I(inode)->delalloc_extents--;
+
+       return 0;
+}
+
 /*
  * extent_io.c set_bit_hook, used to track delayed allocation
  * bytes in this file, and to maintain the list of inodes that
@@ -1167,6 +1244,7 @@ static int run_delalloc_range(struct inode *inode, struct page *locked_page,
 static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
                       unsigned long old, unsigned long bits)
 {
+
        /*
         * set_bit and clear bit hooks normally require _irqsave/restore
         * but in this case, we are only testeing for the DELALLOC
@@ -1174,6 +1252,8 @@ static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
         */
        if (!(old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
                struct btrfs_root *root = BTRFS_I(inode)->root;
+
+               BTRFS_I(inode)->delalloc_extents++;
                btrfs_delalloc_reserve_space(root, inode, end - start + 1);
                spin_lock(&root->fs_info->delalloc_lock);
                BTRFS_I(inode)->delalloc_bytes += end - start + 1;
@@ -1190,22 +1270,27 @@ static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
 /*
  * extent_io.c clear_bit_hook, see set_bit_hook for why
  */
-static int btrfs_clear_bit_hook(struct inode *inode, u64 start, u64 end,
-                        unsigned long old, unsigned long bits)
+static int btrfs_clear_bit_hook(struct inode *inode,
+                               struct extent_state *state, unsigned long bits)
 {
        /*
         * set_bit and clear bit hooks normally require _irqsave/restore
         * but in this case, we are only testeing for the DELALLOC
         * bit, which is only set or cleared with irqs on
         */
-       if ((old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
+       if ((state->state & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
                struct btrfs_root *root = BTRFS_I(inode)->root;
 
+               BTRFS_I(inode)->delalloc_extents--;
+               btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
+
                spin_lock(&root->fs_info->delalloc_lock);
-               if (end - start + 1 > root->fs_info->delalloc_bytes) {
+               if (state->end - state->start + 1 >
+                   root->fs_info->delalloc_bytes) {
                        printk(KERN_INFO "btrfs warning: delalloc account "
                               "%llu %llu\n",
-                              (unsigned long long)end - start + 1,
+                              (unsigned long long)
+                              state->end - state->start + 1,
                               (unsigned long long)
                               root->fs_info->delalloc_bytes);
                        btrfs_delalloc_free_space(root, inode, (u64)-1);
@@ -1213,9 +1298,12 @@ static int btrfs_clear_bit_hook(struct inode *inode, u64 start, u64 end,
                        BTRFS_I(inode)->delalloc_bytes = 0;
                } else {
                        btrfs_delalloc_free_space(root, inode,
-                                                 end - start + 1);
-                       root->fs_info->delalloc_bytes -= end - start + 1;
-                       BTRFS_I(inode)->delalloc_bytes -= end - start + 1;
+                                                 state->end -
+                                                 state->start + 1);
+                       root->fs_info->delalloc_bytes -= state->end -
+                               state->start + 1;
+                       BTRFS_I(inode)->delalloc_bytes -= state->end -
+                               state->start + 1;
                }
                if (BTRFS_I(inode)->delalloc_bytes == 0 &&
                    !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
@@ -2373,6 +2461,69 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
        return ret;
 }
 
+int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
+                       struct btrfs_root *root,
+                       struct inode *dir, u64 objectid,
+                       const char *name, int name_len)
+{
+       struct btrfs_path *path;
+       struct extent_buffer *leaf;
+       struct btrfs_dir_item *di;
+       struct btrfs_key key;
+       u64 index;
+       int ret;
+
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+       di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
+                                  name, name_len, -1);
+       BUG_ON(!di || IS_ERR(di));
+
+       leaf = path->nodes[0];
+       btrfs_dir_item_key_to_cpu(leaf, di, &key);
+       WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
+       ret = btrfs_delete_one_dir_name(trans, root, path, di);
+       BUG_ON(ret);
+       btrfs_release_path(root, path);
+
+       ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
+                                objectid, root->root_key.objectid,
+                                dir->i_ino, &index, name, name_len);
+       if (ret < 0) {
+               BUG_ON(ret != -ENOENT);
+               di = btrfs_search_dir_index_item(root, path, dir->i_ino,
+                                                name, name_len);
+               BUG_ON(!di || IS_ERR(di));
+
+               leaf = path->nodes[0];
+               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               btrfs_release_path(root, path);
+               index = key.offset;
+       }
+
+       di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
+                                        index, name, name_len, -1);
+       BUG_ON(!di || IS_ERR(di));
+
+       leaf = path->nodes[0];
+       btrfs_dir_item_key_to_cpu(leaf, di, &key);
+       WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
+       ret = btrfs_delete_one_dir_name(trans, root, path, di);
+       BUG_ON(ret);
+       btrfs_release_path(root, path);
+
+       btrfs_i_size_write(dir, dir->i_size - name_len * 2);
+       dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+       ret = btrfs_update_inode(trans, root, dir);
+       BUG_ON(ret);
+       dir->i_sb->s_dirt = 1;
+
+       btrfs_free_path(path);
+       return 0;
+}
+
 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
        struct inode *inode = dentry->d_inode;
@@ -2382,29 +2533,31 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
        struct btrfs_trans_handle *trans;
        unsigned long nr = 0;
 
-       /*
-        * the FIRST_FREE_OBJECTID check makes sure we don't try to rmdir
-        * the root of a subvolume or snapshot
-        */
        if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
-           inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
+           inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
                return -ENOTEMPTY;
-       }
 
        trans = btrfs_start_transaction(root, 1);
        btrfs_set_trans_block_group(trans, dir);
 
+       if (unlikely(inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
+               err = btrfs_unlink_subvol(trans, root, dir,
+                                         BTRFS_I(inode)->location.objectid,
+                                         dentry->d_name.name,
+                                         dentry->d_name.len);
+               goto out;
+       }
+
        err = btrfs_orphan_add(trans, inode);
        if (err)
-               goto fail_trans;
+               goto out;
 
        /* now the directory is empty */
        err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
                                 dentry->d_name.name, dentry->d_name.len);
        if (!err)
                btrfs_i_size_write(inode, 0);
-
-fail_trans:
+out:
        nr = trans->blocks_used;
        ret = btrfs_end_transaction_throttle(trans, root);
        btrfs_btree_balance_dirty(root, nr);
@@ -2885,7 +3038,12 @@ again:
                goto again;
        }
 
-       btrfs_set_extent_delalloc(inode, page_start, page_end);
+       ret = btrfs_set_extent_delalloc(inode, page_start, page_end);
+       if (ret) {
+               unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+               goto out_unlock;
+       }
+
        ret = 0;
        if (offset != PAGE_CACHE_SIZE) {
                kaddr = kmap(page);
@@ -2916,15 +3074,11 @@ int btrfs_cont_expand(struct inode *inode, loff_t size)
        u64 last_byte;
        u64 cur_offset;
        u64 hole_size;
-       int err;
+       int err = 0;
 
        if (size <= hole_start)
                return 0;
 
-       err = btrfs_check_metadata_free_space(root);
-       if (err)
-               return err;
-
        btrfs_truncate_page(inode->i_mapping, inode->i_size);
 
        while (1) {
@@ -2959,12 +3113,18 @@ int btrfs_cont_expand(struct inode *inode, loff_t size)
                                                 cur_offset, &hint_byte, 1);
                        if (err)
                                break;
+
+                       err = btrfs_reserve_metadata_space(root, 1);
+                       if (err)
+                               break;
+
                        err = btrfs_insert_file_extent(trans, root,
                                        inode->i_ino, cur_offset, 0,
                                        0, hole_size, 0, hole_size,
                                        0, 0, 0);
                        btrfs_drop_extent_cache(inode, hole_start,
                                        last_byte - 1, 0);
+                       btrfs_unreserve_metadata_space(root, 1);
                }
                free_extent_map(em);
                cur_offset = last_byte;
@@ -3024,6 +3184,11 @@ void btrfs_delete_inode(struct inode *inode)
        }
        btrfs_wait_ordered_range(inode, 0, (u64)-1);
 
+       if (inode->i_nlink > 0) {
+               BUG_ON(btrfs_root_refs(&root->root_item) != 0);
+               goto no_delete;
+       }
+
        btrfs_i_size_write(inode, 0);
        trans = btrfs_join_transaction(root, 1);
 
@@ -3091,29 +3256,67 @@ out_err:
  * is kind of like crossing a mount point.
  */
 static int fixup_tree_root_location(struct btrfs_root *root,
-                            struct btrfs_key *location,
-                            struct btrfs_root **sub_root,
-                            struct dentry *dentry)
+                                   struct inode *dir,
+                                   struct dentry *dentry,
+                                   struct btrfs_key *location,
+                                   struct btrfs_root **sub_root)
 {
-       struct btrfs_root_item *ri;
+       struct btrfs_path *path;
+       struct btrfs_root *new_root;
+       struct btrfs_root_ref *ref;
+       struct extent_buffer *leaf;
+       int ret;
+       int err = 0;
 
-       if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
-               return 0;
-       if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
-               return 0;
+       path = btrfs_alloc_path();
+       if (!path) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       err = -ENOENT;
+       ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
+                                 BTRFS_I(dir)->root->root_key.objectid,
+                                 location->objectid);
+       if (ret) {
+               if (ret < 0)
+                       err = ret;
+               goto out;
+       }
 
-       *sub_root = btrfs_read_fs_root(root->fs_info, location,
-                                       dentry->d_name.name,
-                                       dentry->d_name.len);
-       if (IS_ERR(*sub_root))
-               return PTR_ERR(*sub_root);
+       leaf = path->nodes[0];
+       ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
+       if (btrfs_root_ref_dirid(leaf, ref) != dir->i_ino ||
+           btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
+               goto out;
 
-       ri = &(*sub_root)->root_item;
-       location->objectid = btrfs_root_dirid(ri);
-       btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
-       location->offset = 0;
+       ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
+                                  (unsigned long)(ref + 1),
+                                  dentry->d_name.len);
+       if (ret)
+               goto out;
 
-       return 0;
+       btrfs_release_path(root->fs_info->tree_root, path);
+
+       new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
+       if (IS_ERR(new_root)) {
+               err = PTR_ERR(new_root);
+               goto out;
+       }
+
+       if (btrfs_root_refs(&new_root->root_item) == 0) {
+               err = -ENOENT;
+               goto out;
+       }
+
+       *sub_root = new_root;
+       location->objectid = btrfs_root_dirid(&new_root->root_item);
+       location->type = BTRFS_INODE_ITEM_KEY;
+       location->offset = 0;
+       err = 0;
+out:
+       btrfs_free_path(path);
+       return err;
 }
 
 static void inode_tree_add(struct inode *inode)
@@ -3122,11 +3325,13 @@ static void inode_tree_add(struct inode *inode)
        struct btrfs_inode *entry;
        struct rb_node **p;
        struct rb_node *parent;
-
 again:
        p = &root->inode_tree.rb_node;
        parent = NULL;
 
+       if (hlist_unhashed(&inode->i_hash))
+               return;
+
        spin_lock(&root->inode_lock);
        while (*p) {
                parent = *p;
@@ -3153,13 +3358,87 @@ again:
 static void inode_tree_del(struct inode *inode)
 {
        struct btrfs_root *root = BTRFS_I(inode)->root;
+       int empty = 0;
 
        spin_lock(&root->inode_lock);
        if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
                rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
                RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
+               empty = RB_EMPTY_ROOT(&root->inode_tree);
        }
        spin_unlock(&root->inode_lock);
+
+       if (empty && btrfs_root_refs(&root->root_item) == 0) {
+               synchronize_srcu(&root->fs_info->subvol_srcu);
+               spin_lock(&root->inode_lock);
+               empty = RB_EMPTY_ROOT(&root->inode_tree);
+               spin_unlock(&root->inode_lock);
+               if (empty)
+                       btrfs_add_dead_root(root);
+       }
+}
+
+int btrfs_invalidate_inodes(struct btrfs_root *root)
+{
+       struct rb_node *node;
+       struct rb_node *prev;
+       struct btrfs_inode *entry;
+       struct inode *inode;
+       u64 objectid = 0;
+
+       WARN_ON(btrfs_root_refs(&root->root_item) != 0);
+
+       spin_lock(&root->inode_lock);
+again:
+       node = root->inode_tree.rb_node;
+       prev = NULL;
+       while (node) {
+               prev = node;
+               entry = rb_entry(node, struct btrfs_inode, rb_node);
+
+               if (objectid < entry->vfs_inode.i_ino)
+                       node = node->rb_left;
+               else if (objectid > entry->vfs_inode.i_ino)
+                       node = node->rb_right;
+               else
+                       break;
+       }
+       if (!node) {
+               while (prev) {
+                       entry = rb_entry(prev, struct btrfs_inode, rb_node);
+                       if (objectid <= entry->vfs_inode.i_ino) {
+                               node = prev;
+                               break;
+                       }
+                       prev = rb_next(prev);
+               }
+       }
+       while (node) {
+               entry = rb_entry(node, struct btrfs_inode, rb_node);
+               objectid = entry->vfs_inode.i_ino + 1;
+               inode = igrab(&entry->vfs_inode);
+               if (inode) {
+                       spin_unlock(&root->inode_lock);
+                       if (atomic_read(&inode->i_count) > 1)
+                               d_prune_aliases(inode);
+                       /*
+                        * btrfs_drop_inode will remove it from
+                        * the inode cache when its usage count
+                        * hits zero.
+                        */
+                       iput(inode);
+                       cond_resched();
+                       spin_lock(&root->inode_lock);
+                       goto again;
+               }
+
+               if (cond_resched_lock(&root->inode_lock))
+                       goto again;
+
+               node = rb_next(node);
+       }
+       spin_unlock(&root->inode_lock);
+       return 0;
 }
 
 static noinline void init_btrfs_i(struct inode *inode)
@@ -3246,15 +3525,41 @@ struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
        return inode;
 }
 
+static struct inode *new_simple_dir(struct super_block *s,
+                                   struct btrfs_key *key,
+                                   struct btrfs_root *root)
+{
+       struct inode *inode = new_inode(s);
+
+       if (!inode)
+               return ERR_PTR(-ENOMEM);
+
+       init_btrfs_i(inode);
+
+       BTRFS_I(inode)->root = root;
+       memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
+       BTRFS_I(inode)->dummy_inode = 1;
+
+       inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
+       inode->i_op = &simple_dir_inode_operations;
+       inode->i_fop = &simple_dir_operations;
+       inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
+       inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+
+       return inode;
+}
+
 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
 {
        struct inode *inode;
-       struct btrfs_inode *bi = BTRFS_I(dir);
-       struct btrfs_root *root = bi->root;
+       struct btrfs_root *root = BTRFS_I(dir)->root;
        struct btrfs_root *sub_root = root;
        struct btrfs_key location;
+       int index;
        int ret;
 
+       dentry->d_op = &btrfs_dentry_operations;
+
        if (dentry->d_name.len > BTRFS_NAME_LEN)
                return ERR_PTR(-ENAMETOOLONG);
 
@@ -3263,29 +3568,50 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
        if (ret < 0)
                return ERR_PTR(ret);
 
-       inode = NULL;
-       if (location.objectid) {
-               ret = fixup_tree_root_location(root, &location, &sub_root,
-                                               dentry);
-               if (ret < 0)
-                       return ERR_PTR(ret);
-               if (ret > 0)
-                       return ERR_PTR(-ENOENT);
+       if (location.objectid == 0)
+               return NULL;
+
+       if (location.type == BTRFS_INODE_ITEM_KEY) {
+               inode = btrfs_iget(dir->i_sb, &location, root);
+               return inode;
+       }
+
+       BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
+
+       index = srcu_read_lock(&root->fs_info->subvol_srcu);
+       ret = fixup_tree_root_location(root, dir, dentry,
+                                      &location, &sub_root);
+       if (ret < 0) {
+               if (ret != -ENOENT)
+                       inode = ERR_PTR(ret);
+               else
+                       inode = new_simple_dir(dir->i_sb, &location, sub_root);
+       } else {
                inode = btrfs_iget(dir->i_sb, &location, sub_root);
-               if (IS_ERR(inode))
-                       return ERR_CAST(inode);
        }
+       srcu_read_unlock(&root->fs_info->subvol_srcu, index);
+
        return inode;
 }
 
+static int btrfs_dentry_delete(struct dentry *dentry)
+{
+       struct btrfs_root *root;
+
+       if (!dentry->d_inode)
+               return 0;
+
+       root = BTRFS_I(dentry->d_inode)->root;
+       if (btrfs_root_refs(&root->root_item) == 0)
+               return 1;
+       return 0;
+}
+
 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
                                   struct nameidata *nd)
 {
        struct inode *inode;
 
-       if (dentry->d_name.len > BTRFS_NAME_LEN)
-               return ERR_PTR(-ENAMETOOLONG);
-
        inode = btrfs_lookup_dentry(dir, dentry);
        if (IS_ERR(inode))
                return ERR_CAST(inode);
@@ -3624,9 +3950,6 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
        if (ret != 0)
                goto fail;
 
-       if (objectid > root->highest_inode)
-               root->highest_inode = objectid;
-
        inode->i_uid = current_fsuid();
 
        if (dir && (dir->i_mode & S_ISGID)) {
@@ -3694,26 +4017,35 @@ int btrfs_add_link(struct btrfs_trans_handle *trans,
                   struct inode *parent_inode, struct inode *inode,
                   const char *name, int name_len, int add_backref, u64 index)
 {
-       int ret;
+       int ret = 0;
        struct btrfs_key key;
        struct btrfs_root *root = BTRFS_I(parent_inode)->root;
 
-       key.objectid = inode->i_ino;
-       btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
-       key.offset = 0;
+       if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+               memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
+       } else {
+               key.objectid = inode->i_ino;
+               btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+               key.offset = 0;
+       }
+
+       if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+               ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
+                                        key.objectid, root->root_key.objectid,
+                                        parent_inode->i_ino,
+                                        index, name, name_len);
+       } else if (add_backref) {
+               ret = btrfs_insert_inode_ref(trans, root,
+                                            name, name_len, inode->i_ino,
+                                            parent_inode->i_ino, index);
+       }
 
-       ret = btrfs_insert_dir_item(trans, root, name, name_len,
-                                   parent_inode->i_ino,
-                                   &key, btrfs_inode_type(inode),
-                                   index);
        if (ret == 0) {
-               if (add_backref) {
-                       ret = btrfs_insert_inode_ref(trans, root,
-                                                    name, name_len,
-                                                    inode->i_ino,
-                                                    parent_inode->i_ino,
-                                                    index);
-               }
+               ret = btrfs_insert_dir_item(trans, root, name, name_len,
+                                           parent_inode->i_ino, &key,
+                                           btrfs_inode_type(inode), index);
+               BUG_ON(ret);
+
                btrfs_i_size_write(parent_inode, parent_inode->i_size +
                                   name_len * 2);
                parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
@@ -3753,11 +4085,18 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
        if (!new_valid_dev(rdev))
                return -EINVAL;
 
-       err = btrfs_check_metadata_free_space(root);
+       /*
+        * 2 for inode item and ref
+        * 2 for dir items
+        * 1 for xattr if selinux is on
+        */
+       err = btrfs_reserve_metadata_space(root, 5);
        if (err)
-               goto fail;
+               return err;
 
        trans = btrfs_start_transaction(root, 1);
+       if (!trans)
+               goto fail;
        btrfs_set_trans_block_group(trans, dir);
 
        err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
@@ -3795,6 +4134,7 @@ out_unlock:
        nr = trans->blocks_used;
        btrfs_end_transaction_throttle(trans, root);
 fail:
+       btrfs_unreserve_metadata_space(root, 5);
        if (drop_inode) {
                inode_dec_link_count(inode);
                iput(inode);
@@ -3815,10 +4155,18 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
        u64 objectid;
        u64 index = 0;
 
-       err = btrfs_check_metadata_free_space(root);
+       /*
+        * 2 for inode item and ref
+        * 2 for dir items
+        * 1 for xattr if selinux is on
+        */
+       err = btrfs_reserve_metadata_space(root, 5);
        if (err)
-               goto fail;
+               return err;
+
        trans = btrfs_start_transaction(root, 1);
+       if (!trans)
+               goto fail;
        btrfs_set_trans_block_group(trans, dir);
 
        err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
@@ -3859,6 +4207,7 @@ out_unlock:
        nr = trans->blocks_used;
        btrfs_end_transaction_throttle(trans, root);
 fail:
+       btrfs_unreserve_metadata_space(root, 5);
        if (drop_inode) {
                inode_dec_link_count(inode);
                iput(inode);
@@ -3881,10 +4230,16 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
        if (inode->i_nlink == 0)
                return -ENOENT;
 
-       btrfs_inc_nlink(inode);
-       err = btrfs_check_metadata_free_space(root);
+       /*
+        * 1 item for inode ref
+        * 2 items for dir items
+        */
+       err = btrfs_reserve_metadata_space(root, 3);
        if (err)
-               goto fail;
+               return err;
+
+       btrfs_inc_nlink(inode);
+
        err = btrfs_set_inode_index(dir, &index);
        if (err)
                goto fail;
@@ -3896,20 +4251,19 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 
        err = btrfs_add_nondir(trans, dentry, inode, 1, index);
 
-       if (err)
-               drop_inode = 1;
-
-       btrfs_update_inode_block_group(trans, dir);
-       err = btrfs_update_inode(trans, root, inode);
-
-       if (err)
+       if (err) {
                drop_inode = 1;
+       } else {
+               btrfs_update_inode_block_group(trans, dir);
+               err = btrfs_update_inode(trans, root, inode);
+               BUG_ON(err);
+               btrfs_log_new_name(trans, inode, NULL, dentry->d_parent);
+       }
 
        nr = trans->blocks_used;
-
-       btrfs_log_new_name(trans, inode, NULL, dentry->d_parent);
        btrfs_end_transaction_throttle(trans, root);
 fail:
+       btrfs_unreserve_metadata_space(root, 3);
        if (drop_inode) {
                inode_dec_link_count(inode);
                iput(inode);
@@ -3929,17 +4283,21 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
        u64 index = 0;
        unsigned long nr = 1;
 
-       err = btrfs_check_metadata_free_space(root);
+       /*
+        * 2 items for inode and ref
+        * 2 items for dir items
+        * 1 for xattr if selinux is on
+        */
+       err = btrfs_reserve_metadata_space(root, 5);
        if (err)
-               goto out_unlock;
+               return err;
 
        trans = btrfs_start_transaction(root, 1);
-       btrfs_set_trans_block_group(trans, dir);
-
-       if (IS_ERR(trans)) {
-               err = PTR_ERR(trans);
+       if (!trans) {
+               err = -ENOMEM;
                goto out_unlock;
        }
+       btrfs_set_trans_block_group(trans, dir);
 
        err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
        if (err) {
@@ -3988,6 +4346,7 @@ out_fail:
        btrfs_end_transaction_throttle(trans, root);
 
 out_unlock:
+       btrfs_unreserve_metadata_space(root, 5);
        if (drop_on_err)
                iput(inode);
        btrfs_btree_balance_dirty(root, nr);
@@ -4512,6 +4871,13 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
                goto out;
        }
 
+       ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
+       if (ret) {
+               btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
+               ret = VM_FAULT_SIGBUS;
+               goto out;
+       }
+
        ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
 again:
        lock_page(page);
@@ -4543,7 +4909,23 @@ again:
                goto again;
        }
 
-       btrfs_set_extent_delalloc(inode, page_start, page_end);
+       /*
+        * XXX - page_mkwrite gets called every time the page is dirtied, even
+        * if it was already dirty, so for space accounting reasons we need to
+        * clear any delalloc bits for the range we are fixing to save.  There
+        * is probably a better way to do this, but for now keep consistent with
+        * prepare_pages in the normal write path.
+        */
+       clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
+                         EXTENT_DIRTY | EXTENT_DELALLOC, GFP_NOFS);
+
+       ret = btrfs_set_extent_delalloc(inode, page_start, page_end);
+       if (ret) {
+               unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+               ret = VM_FAULT_SIGBUS;
+               btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
+               goto out_unlock;
+       }
        ret = 0;
 
        /* page is wholly or partially inside EOF */
@@ -4566,6 +4948,7 @@ again:
        unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 
 out_unlock:
+       btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
        if (!ret)
                return VM_FAULT_LOCKED;
        unlock_page(page);
@@ -4636,11 +5019,11 @@ out:
  * create a new subvolume directory/inode (helper for the ioctl).
  */
 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
-                            struct btrfs_root *new_root, struct dentry *dentry,
+                            struct btrfs_root *new_root,
                             u64 new_dirid, u64 alloc_hint)
 {
        struct inode *inode;
-       int error;
+       int err;
        u64 index = 0;
 
        inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
@@ -4653,11 +5036,10 @@ int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
        inode->i_nlink = 1;
        btrfs_i_size_write(inode, 0);
 
-       error = btrfs_update_inode(trans, new_root, inode);
-       if (error)
-               return error;
+       err = btrfs_update_inode(trans, new_root, inode);
+       BUG_ON(err);
 
-       d_instantiate(dentry, inode);
+       iput(inode);
        return 0;
 }
 
@@ -4683,6 +5065,8 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
                return NULL;
        ei->last_trans = 0;
        ei->logged_trans = 0;
+       ei->delalloc_extents = 0;
+       ei->delalloc_reserved_extents = 0;
        btrfs_ordered_inode_tree_init(&ei->ordered_tree);
        INIT_LIST_HEAD(&ei->i_orphan);
        INIT_LIST_HEAD(&ei->ordered_operations);
@@ -4735,6 +5119,16 @@ void btrfs_destroy_inode(struct inode *inode)
        kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
+void btrfs_drop_inode(struct inode *inode)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+
+       if (inode->i_nlink > 0 && btrfs_root_refs(&root->root_item) == 0)
+               generic_delete_inode(inode);
+       else
+               generic_drop_inode(inode);
+}
+
 static void init_once(void *foo)
 {
        struct btrfs_inode *ei = (struct btrfs_inode *) foo;
@@ -4803,31 +5197,37 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 {
        struct btrfs_trans_handle *trans;
        struct btrfs_root *root = BTRFS_I(old_dir)->root;
+       struct btrfs_root *dest = BTRFS_I(new_dir)->root;
        struct inode *new_inode = new_dentry->d_inode;
        struct inode *old_inode = old_dentry->d_inode;
        struct timespec ctime = CURRENT_TIME;
        u64 index = 0;
+       u64 root_objectid;
        int ret;
 
-       /* we're not allowed to rename between subvolumes */
-       if (BTRFS_I(old_inode)->root->root_key.objectid !=
-           BTRFS_I(new_dir)->root->root_key.objectid)
+       if (new_dir->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
+               return -EPERM;
+
+       /* we only allow rename subvolume link between subvolumes */
+       if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
                return -EXDEV;
 
+       if (old_inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
+           (new_inode && new_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID))
+               return -ENOTEMPTY;
+
        if (S_ISDIR(old_inode->i_mode) && new_inode &&
-           new_inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
+           new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
                return -ENOTEMPTY;
-       }
 
-       /* to rename a snapshot or subvolume, we need to juggle the
-        * backrefs.  This isn't coded yet
+       /*
+        * 2 items for dir items
+        * 1 item for orphan entry
+        * 1 item for ref
         */
-       if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
-               return -EXDEV;
-
-       ret = btrfs_check_metadata_free_space(root);
+       ret = btrfs_reserve_metadata_space(root, 4);
        if (ret)
-               goto out_unlock;
+               return ret;
 
        /*
         * we're using rename to replace one file with another.
@@ -4838,8 +5238,40 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
            old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
                filemap_flush(old_inode->i_mapping);
 
+       /* close the racy window with snapshot create/destroy ioctl */
+       if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
+               down_read(&root->fs_info->subvol_sem);
+
        trans = btrfs_start_transaction(root, 1);
+       btrfs_set_trans_block_group(trans, new_dir);
 
+       if (dest != root)
+               btrfs_record_root_in_trans(trans, dest);
+
+       ret = btrfs_set_inode_index(new_dir, &index);
+       if (ret)
+               goto out_fail;
+
+       if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+               /* force full log commit if subvolume involved. */
+               root->fs_info->last_trans_log_full_commit = trans->transid;
+       } else {
+               ret = btrfs_insert_inode_ref(trans, dest,
+                                            new_dentry->d_name.name,
+                                            new_dentry->d_name.len,
+                                            old_inode->i_ino,
+                                            new_dir->i_ino, index);
+               if (ret)
+                       goto out_fail;
+               /*
+                * this is an ugly little race, but the rename is required
+                * to make sure that if we crash, the inode is either at the
+                * old name or the new one.  pinning the log transaction lets
+                * us make sure we don't allow a log commit to come in after
+                * we unlink the name but before we add the new name back in.
+                */
+               btrfs_pin_log_trans(root);
+       }
        /*
         * make sure the inode gets flushed if it is replacing
         * something.
@@ -4849,18 +5281,6 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
                btrfs_add_ordered_operation(trans, root, old_inode);
        }
 
-       /*
-        * this is an ugly little race, but the rename is required to make
-        * sure that if we crash, the inode is either at the old name
-        * or the new one.  pinning the log transaction lets us make sure
-        * we don't allow a log commit to come in after we unlink the
-        * name but before we add the new name back in.
-        */
-       btrfs_pin_log_trans(root);
-
-       btrfs_set_trans_block_group(trans, new_dir);
-
-       btrfs_inc_nlink(old_dentry->d_inode);
        old_dir->i_ctime = old_dir->i_mtime = ctime;
        new_dir->i_ctime = new_dir->i_mtime = ctime;
        old_inode->i_ctime = ctime;
@@ -4868,47 +5288,60 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
        if (old_dentry->d_parent != new_dentry->d_parent)
                btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
 
-       ret = btrfs_unlink_inode(trans, root, old_dir, old_dentry->d_inode,
-                                old_dentry->d_name.name,
-                                old_dentry->d_name.len);
-       if (ret)
-               goto out_fail;
+       if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+               root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
+               ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
+                                       old_dentry->d_name.name,
+                                       old_dentry->d_name.len);
+       } else {
+               btrfs_inc_nlink(old_dentry->d_inode);
+               ret = btrfs_unlink_inode(trans, root, old_dir,
+                                        old_dentry->d_inode,
+                                        old_dentry->d_name.name,
+                                        old_dentry->d_name.len);
+       }
+       BUG_ON(ret);
 
        if (new_inode) {
                new_inode->i_ctime = CURRENT_TIME;
-               ret = btrfs_unlink_inode(trans, root, new_dir,
-                                        new_dentry->d_inode,
-                                        new_dentry->d_name.name,
-                                        new_dentry->d_name.len);
-               if (ret)
-                       goto out_fail;
+               if (unlikely(new_inode->i_ino ==
+                            BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
+                       root_objectid = BTRFS_I(new_inode)->location.objectid;
+                       ret = btrfs_unlink_subvol(trans, dest, new_dir,
+                                               root_objectid,
+                                               new_dentry->d_name.name,
+                                               new_dentry->d_name.len);
+                       BUG_ON(new_inode->i_nlink == 0);
+               } else {
+                       ret = btrfs_unlink_inode(trans, dest, new_dir,
+                                                new_dentry->d_inode,
+                                                new_dentry->d_name.name,
+                                                new_dentry->d_name.len);
+               }
+               BUG_ON(ret);
                if (new_inode->i_nlink == 0) {
                        ret = btrfs_orphan_add(trans, new_dentry->d_inode);
-                       if (ret)
-                               goto out_fail;
+                       BUG_ON(ret);
                }
-
        }
-       ret = btrfs_set_inode_index(new_dir, &index);
-       if (ret)
-               goto out_fail;
 
-       ret = btrfs_add_link(trans, new_dentry->d_parent->d_inode,
-                            old_inode, new_dentry->d_name.name,
-                            new_dentry->d_name.len, 1, index);
-       if (ret)
-               goto out_fail;
+       ret = btrfs_add_link(trans, new_dir, old_inode,
+                            new_dentry->d_name.name,
+                            new_dentry->d_name.len, 0, index);
+       BUG_ON(ret);
 
-       btrfs_log_new_name(trans, old_inode, old_dir,
-                                      new_dentry->d_parent);
+       if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
+               btrfs_log_new_name(trans, old_inode, old_dir,
+                                  new_dentry->d_parent);
+               btrfs_end_log_trans(root);
+       }
 out_fail:
-
-       /* this btrfs_end_log_trans just allows the current
-        * log-sub transaction to complete
-        */
-       btrfs_end_log_trans(root);
        btrfs_end_transaction_throttle(trans, root);
-out_unlock:
+
+       if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
+               up_read(&root->fs_info->subvol_sem);
+
+       btrfs_unreserve_metadata_space(root, 4);
        return ret;
 }
 
@@ -4980,11 +5413,18 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
        if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
                return -ENAMETOOLONG;
 
-       err = btrfs_check_metadata_free_space(root);
+       /*
+        * 2 items for inode item and ref
+        * 2 items for dir items
+        * 1 item for xattr if selinux is on
+        */
+       err = btrfs_reserve_metadata_space(root, 5);
        if (err)
-               goto out_fail;
+               return err;
 
        trans = btrfs_start_transaction(root, 1);
+       if (!trans)
+               goto out_fail;
        btrfs_set_trans_block_group(trans, dir);
 
        err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
@@ -5065,6 +5505,7 @@ out_unlock:
        nr = trans->blocks_used;
        btrfs_end_transaction_throttle(trans, root);
 out_fail:
+       btrfs_unreserve_metadata_space(root, 5);
        if (drop_inode) {
                inode_dec_link_count(inode);
                iput(inode);
@@ -5086,6 +5527,11 @@ static int prealloc_file_range(struct btrfs_trans_handle *trans,
 
        while (num_bytes > 0) {
                alloc_size = min(num_bytes, root->fs_info->max_extent);
+
+               ret = btrfs_reserve_metadata_space(root, 1);
+               if (ret)
+                       goto out;
+
                ret = btrfs_reserve_extent(trans, root, alloc_size,
                                           root->sectorsize, 0, alloc_hint,
                                           (u64)-1, &ins, 1);
@@ -5105,6 +5551,7 @@ static int prealloc_file_range(struct btrfs_trans_handle *trans,
                num_bytes -= ins.offset;
                cur_offset += ins.offset;
                alloc_hint = ins.objectid + ins.offset;
+               btrfs_unreserve_metadata_space(root, 1);
        }
 out:
        if (cur_offset > start) {
@@ -5267,6 +5714,7 @@ static struct inode_operations btrfs_dir_ro_inode_operations = {
        .lookup         = btrfs_lookup,
        .permission     = btrfs_permission,
 };
+
 static struct file_operations btrfs_dir_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = generic_read_dir,
@@ -5289,6 +5737,8 @@ static struct extent_io_ops btrfs_extent_io_ops = {
        .readpage_io_failed_hook = btrfs_io_failed_hook,
        .set_bit_hook = btrfs_set_bit_hook,
        .clear_bit_hook = btrfs_clear_bit_hook,
+       .merge_extent_hook = btrfs_merge_extent_hook,
+       .split_extent_hook = btrfs_split_extent_hook,
 };
 
 /*
@@ -5353,3 +5803,7 @@ static struct inode_operations btrfs_symlink_inode_operations = {
        .listxattr      = btrfs_listxattr,
        .removexattr    = btrfs_removexattr,
 };
+
+struct dentry_operations btrfs_dentry_operations = {
+       .d_delete       = btrfs_dentry_delete,
+};
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