Btrfs: cleanup to make the function btrfs_delalloc_reserve_metadata more logic

The original code is a little confusing and not clear, The right
way to deal with the kernel code like this:
		[...]
		if (ret)
			goto out;
		[...]

So i move the common clean_up code to the place labeled with
out_fail, this will be easier to maintain.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 38 insertions, 44 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 075854e7a044..aaee2b7fee78 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4721,6 +4721,8 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
         int ret = 0;
         bool delalloc_lock = true;
+        u64 to_free = 0;
+        unsigned dropped;
 
         /* If we are a free space inode we need to not flush since we will be in
          * the middle of a transaction commit.  We also don't need the delalloc
@@ -4764,55 +4766,19 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         csum_bytes = BTRFS_I(inode)->csum_bytes;
         spin_unlock(&BTRFS_I(inode)->lock);
 
-        if (root->fs_info->quota_enabled)
+        if (root->fs_info->quota_enabled) {
                 ret = btrfs_qgroup_reserve(root, num_bytes +
                                            nr_extents * root->leafsize);
+                if (ret)
+                        goto out_fail;
+        }
 
-        /*
-         * ret != 0 here means the qgroup reservation failed, we go straight to
-         * the shared error handling then.
-         */
-        if (ret == 0) {
-                ret = reserve_metadata_bytes(root, block_rsv,
-                                             to_reserve, flush);
-                if (ret && root->fs_info->quota_enabled) {
+        ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
+        if (unlikely(ret)) {
+                if (root->fs_info->quota_enabled)
                         btrfs_qgroup_free(root, num_bytes +
                                                 nr_extents * root->leafsize);
-                }
-        }
-
-        if (ret) {
-                u64 to_free = 0;
-                unsigned dropped;
-
-                spin_lock(&BTRFS_I(inode)->lock);
-                dropped = drop_outstanding_extent(inode);
-                /*
-                 * If the inodes csum_bytes is the same as the original
-                 * csum_bytes then we know we haven't raced with any free()ers
-                 * so we can just reduce our inodes csum bytes and carry on.
-                 * Otherwise we have to do the normal free thing to account for
-                 * the case that the free side didn't free up its reserve
-                 * because of this outstanding reservation.
-                 */
-                if (BTRFS_I(inode)->csum_bytes == csum_bytes)
-                        calc_csum_metadata_size(inode, num_bytes, 0);
-                else
-                        to_free = calc_csum_metadata_size(inode, num_bytes, 0);
-                spin_unlock(&BTRFS_I(inode)->lock);
-                if (dropped)
-                        to_free += btrfs_calc_trans_metadata_size(root, dropped);
-
-                if (to_free) {
-                        btrfs_block_rsv_release(root, block_rsv, to_free);
-                        trace_btrfs_space_reservation(root->fs_info,
-                                                      "delalloc",
-                                                      btrfs_ino(inode),
-                                                      to_free, 0);
-                }
-                if (delalloc_lock)
-                        mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
-                return ret;
+                goto out_fail;
         }
 
         spin_lock(&BTRFS_I(inode)->lock);
@@ -4833,6 +4799,34 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         block_rsv_add_bytes(block_rsv, to_reserve, 1);
 
         return 0;
+
+out_fail:
+        spin_lock(&BTRFS_I(inode)->lock);
+        dropped = drop_outstanding_extent(inode);
+        /*
+         * If the inodes csum_bytes is the same as the original
+         * csum_bytes then we know we haven't raced with any free()ers
+         * so we can just reduce our inodes csum bytes and carry on.
+         * Otherwise we have to do the normal free thing to account for
+         * the case that the free side didn't free up its reserve
+         * because of this outstanding reservation.
+         */
+        if (BTRFS_I(inode)->csum_bytes == csum_bytes)
+                calc_csum_metadata_size(inode, num_bytes, 0);
+        else
+                to_free = calc_csum_metadata_size(inode, num_bytes, 0);
+        spin_unlock(&BTRFS_I(inode)->lock);
+        if (dropped)
+                to_free += btrfs_calc_trans_metadata_size(root, dropped);
+
+        if (to_free) {
+                btrfs_block_rsv_release(root, block_rsv, to_free);
+                trace_btrfs_space_reservation(root->fs_info, "delalloc",
+                                              btrfs_ino(inode), to_free, 0);
+        }
+        if (delalloc_lock)
+                mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
+        return ret;
 }
 
 /**