1 files changed, 269 insertions, 59 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e9b76bcd1c12..9e138b793dc7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -62,7 +62,7 @@ static const struct inode_operations btrfs_special_inode_operations;
 static const struct inode_operations btrfs_file_inode_operations;
 static const struct address_space_operations btrfs_aops;
 static const struct address_space_operations btrfs_symlink_aops;
-static struct file_operations btrfs_dir_file_operations;
+static const struct file_operations btrfs_dir_file_operations;
 static struct extent_io_ops btrfs_extent_io_ops;
 
 static struct kmem_cache *btrfs_inode_cachep;
@@ -424,9 +424,12 @@ again:
                          * and free up our temp pages.
                          */
                         extent_clear_unlock_delalloc(inode,
-                                                     &BTRFS_I(inode)->io_tree,
-                                                     start, end, NULL, 1, 0,
-                                                     0, 1, 1, 1, 0);
+                             &BTRFS_I(inode)->io_tree,
+                             start, end, NULL,
+                             EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
+                             EXTENT_CLEAR_DELALLOC |
+                             EXTENT_CLEAR_ACCOUNTING |
+                             EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
                         ret = 0;
                         goto free_pages_out;
                 }
@@ -637,11 +640,14 @@ static noinline int submit_compressed_extents(struct inode *inode,
                  * clear dirty, set writeback and unlock the pages.
                  */
                 extent_clear_unlock_delalloc(inode,
-                                             &BTRFS_I(inode)->io_tree,
-                                             async_extent->start,
-                                             async_extent->start +
-                                             async_extent->ram_size - 1,
-                                             NULL, 1, 1, 0, 1, 1, 0, 0);
+                                &BTRFS_I(inode)->io_tree,
+                                async_extent->start,
+                                async_extent->start +
+                                async_extent->ram_size - 1,
+                                NULL, EXTENT_CLEAR_UNLOCK_PAGE |
+                                EXTENT_CLEAR_UNLOCK |
+                                EXTENT_CLEAR_DELALLOC |
+                                EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
 
                 ret = btrfs_submit_compressed_write(inode,
                                     async_extent->start,
@@ -712,9 +718,15 @@ static noinline int cow_file_range(struct inode *inode,
                                             start, end, 0, NULL);
                 if (ret == 0) {
                         extent_clear_unlock_delalloc(inode,
-                                                     &BTRFS_I(inode)->io_tree,
-                                                     start, end, NULL, 1, 1,
-                                                     1, 1, 1, 1, 0);
+                                     &BTRFS_I(inode)->io_tree,
+                                     start, end, NULL,
+                                     EXTENT_CLEAR_UNLOCK_PAGE |
+                                     EXTENT_CLEAR_UNLOCK |
+                                     EXTENT_CLEAR_DELALLOC |
+                                     EXTENT_CLEAR_ACCOUNTING |
+                                     EXTENT_CLEAR_DIRTY |
+                                     EXTENT_SET_WRITEBACK |
+                                     EXTENT_END_WRITEBACK);
                         *nr_written = *nr_written +
                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
                         *page_started = 1;
@@ -738,6 +750,8 @@ static noinline int cow_file_range(struct inode *inode,
         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 
         while (disk_num_bytes > 0) {
+                unsigned long op;
+
                 cur_alloc_size = min(disk_num_bytes, root->fs_info->max_extent);
                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
                                            root->sectorsize, 0, alloc_hint,
@@ -789,10 +803,13 @@ static noinline int cow_file_range(struct inode *inode,
                  * Do set the Private2 bit so we know this page was properly
                  * setup for writepage
                  */
+                op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
+                op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
+                        EXTENT_SET_PRIVATE2;
+
                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
                                              start, start + ram_size - 1,
-                                             locked_page, unlock, 1,
-                                             1, 0, 0, 0, 1);
+                                             locked_page, op);
                 disk_num_bytes -= cur_alloc_size;
                 num_bytes -= cur_alloc_size;
                 alloc_hint = ins.objectid + ins.offset;
@@ -864,8 +881,8 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page,
         u64 cur_end;
         int limit = 10 * 1024 * 1042;
 
-        clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED |
-                         EXTENT_DELALLOC, 1, 0, NULL, GFP_NOFS);
+        clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
+                         1, 0, NULL, GFP_NOFS);
         while (start < end) {
                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
                 async_cow->inode = inode;
@@ -1006,6 +1023,7 @@ next_slot:
 
                 if (found_key.offset > cur_offset) {
                         extent_end = found_key.offset;
+                        extent_type = 0;
                         goto out_check;
                 }
 
@@ -1112,8 +1130,10 @@ out_check:
                 BUG_ON(ret);
 
                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
-                                        cur_offset, cur_offset + num_bytes - 1,
-                                        locked_page, 1, 1, 1, 0, 0, 0, 1);
+                                cur_offset, cur_offset + num_bytes - 1,
+                                locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
+                                EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
+                                EXTENT_SET_PRIVATE2);
                 cur_offset = extent_end;
                 if (cur_offset > end)
                         break;
@@ -1159,6 +1179,89 @@ 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 oustanding_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;
+        }
+
+        spin_lock(&BTRFS_I(inode)->accounting_lock);
+        BTRFS_I(inode)->outstanding_extents++;
+        spin_unlock(&BTRFS_I(inode)->accounting_lock);
+
+        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) {
+                spin_lock(&BTRFS_I(inode)->accounting_lock);
+                BTRFS_I(inode)->outstanding_extents--;
+                spin_unlock(&BTRFS_I(inode)->accounting_lock);
+                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;
+
+        spin_lock(&BTRFS_I(inode)->accounting_lock);
+        BTRFS_I(inode)->outstanding_extents--;
+        spin_unlock(&BTRFS_I(inode)->accounting_lock);
+
+        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 +1270,7 @@ 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 +1278,10 @@ 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;
+
+                spin_lock(&BTRFS_I(inode)->accounting_lock);
+                BTRFS_I(inode)->outstanding_extents++;
+                spin_unlock(&BTRFS_I(inode)->accounting_lock);
                 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 +1298,31 @@ 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;
 
+                if (bits & EXTENT_DO_ACCOUNTING) {
+                        spin_lock(&BTRFS_I(inode)->accounting_lock);
+                        BTRFS_I(inode)->outstanding_extents--;
+                        spin_unlock(&BTRFS_I(inode)->accounting_lock);
+                        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 +1330,12 @@ 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)) {
@@ -2950,7 +3070,12 @@ 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);
@@ -2981,15 +3106,11 @@ 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) {
@@ -3024,12 +3145,18 @@ 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;
@@ -3503,12 +3630,14 @@ static int btrfs_dentry_delete(struct dentry *dentry)
 {
         struct btrfs_root *root;
 
-        if (!dentry->d_inode)
-                return 0;
+        if (!dentry->d_inode && !IS_ROOT(dentry))
+                dentry = dentry->d_parent;
 
-        root = BTRFS_I(dentry->d_inode)->root;
-        if (btrfs_root_refs(&root->root_item) == 0)
-                return 1;
+        if (dentry->d_inode) {
+                root = BTRFS_I(dentry->d_inode)->root;
+                if (btrfs_root_refs(&root->root_item) == 0)
+                        return 1;
+        }
         return 0;
 }
 
@@ -3990,11 +4119,18 @@ 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);
@@ -4032,6 +4168,7 @@ 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);
@@ -4052,10 +4189,18 @@ 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);
@@ -4096,6 +4241,7 @@ 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);
@@ -4118,10 +4264,16 @@ 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;
@@ -4145,6 +4297,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
         nr = trans->blocks_used;
         btrfs_end_transaction_throttle(trans, root);
 fail:
+        btrfs_unreserve_metadata_space(root, 3);
         if (drop_inode) {
                 inode_dec_link_count(inode);
                 iput(inode);
@@ -4164,17 +4317,21 @@ 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) {
@@ -4223,6 +4380,7 @@ 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);
@@ -4684,7 +4842,8 @@ static void btrfs_invalidatepage(struct page *page, unsigned long offset)
                  */
                 clear_extent_bit(tree, page_start, page_end,
                                  EXTENT_DIRTY | EXTENT_DELALLOC |
-                                 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
+                                 EXTENT_LOCKED | EXTENT_DO_ACCOUNTING, 1, 0,
+                                 NULL, GFP_NOFS);
                 /*
                  * whoever cleared the private bit is responsible
                  * for the finish_ordered_io
@@ -4697,8 +4856,8 @@ static void btrfs_invalidatepage(struct page *page, unsigned long offset)
                 lock_extent(tree, page_start, page_end, GFP_NOFS);
         }
         clear_extent_bit(tree, page_start, page_end,
-                 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
-                 1, 1, NULL, GFP_NOFS);
+                 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
+                 EXTENT_DO_ACCOUNTING, 1, 1, NULL, GFP_NOFS);
         __btrfs_releasepage(page, GFP_NOFS);
 
         ClearPageChecked(page);
@@ -4747,6 +4906,13 @@ 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);
@@ -4778,7 +4944,24 @@ 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 | EXTENT_DO_ACCOUNTING,
+                          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 */
@@ -4801,6 +4984,7 @@ 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);
@@ -4917,6 +5101,9 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
                 return NULL;
         ei->last_trans = 0;
         ei->logged_trans = 0;
+        ei->outstanding_extents = 0;
+        ei->reserved_extents = 0;
+        spin_lock_init(&ei->accounting_lock);
         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
         INIT_LIST_HEAD(&ei->i_orphan);
         INIT_LIST_HEAD(&ei->ordered_operations);
@@ -5070,7 +5257,12 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
                 return -ENOTEMPTY;
 
-        ret = btrfs_check_metadata_free_space(root);
+        /*
+         * 2 items for dir items
+         * 1 item for orphan entry
+         * 1 item for ref
+         */
+        ret = btrfs_reserve_metadata_space(root, 4);
         if (ret)
                 return ret;
 
@@ -5185,6 +5377,8 @@ out_fail:
 
         if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
                 up_read(&root->fs_info->subvol_sem);
+
+        btrfs_unreserve_metadata_space(root, 4);
         return ret;
 }
 
@@ -5256,11 +5450,18 @@ 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);
@@ -5341,6 +5542,7 @@ 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);
@@ -5362,6 +5564,11 @@ 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);
@@ -5381,6 +5588,7 @@ 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) {
@@ -5544,7 +5752,7 @@ static const struct inode_operations btrfs_dir_ro_inode_operations = {
         .permission     = btrfs_permission,
 };
 
-static struct file_operations btrfs_dir_file_operations = {
+static const struct file_operations btrfs_dir_file_operations = {
         .llseek         = generic_file_llseek,
         .read           = generic_read_dir,
         .readdir        = btrfs_real_readdir,
@@ -5566,6 +5774,8 @@ 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,
 };
 
 /*
@@ -5632,6 +5842,6 @@ static const struct inode_operations btrfs_symlink_inode_operations = {
         .removexattr    = btrfs_removexattr,
 };
 
-struct dentry_operations btrfs_dentry_operations = {
+const struct dentry_operations btrfs_dentry_operations = {
         .d_delete       = btrfs_dentry_delete,
 };