btrfs: improved readablity for add_inode_ref

Moved part of the code into a sub function and replaced most of the gotos
by ifs, hoping that it will be easier to read now.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Mark Fasheh <mfasheh@suse.de>

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index e0ef92f..15dae58 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -785,76 +785,18 @@ out:
        return match;
 }
 
-
-/*
- * replay one inode back reference item found in the log tree.
- * eb, slot and key refer to the buffer and key found in the log tree.
- * root is the destination we are replaying into, and path is for temp
- * use by this function.  (it should be released on return).
- */
-static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
+static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
                                  struct btrfs_root *root,
-                                 struct btrfs_root *log,
                                  struct btrfs_path *path,
-                                 struct extent_buffer *eb, int slot,
-                                 struct btrfs_key *key)
+                                 struct btrfs_root *log_root,
+                                 struct inode *dir, struct inode *inode,
+                                 struct btrfs_key *key,
+                                 struct extent_buffer *eb,
+                                 struct btrfs_inode_ref *ref,
+                                 char *name, int namelen, int *search_done)
 {
-       struct btrfs_inode_ref *ref;
-       struct btrfs_dir_item *di;
-       struct inode *dir;
-       struct inode *inode;
-       unsigned long ref_ptr;
-       unsigned long ref_end;
-       char *name;
-       int namelen;
        int ret;
-       int search_done = 0;
-
-       /*
-        * it is possible that we didn't log all the parent directories
-        * for a given inode.  If we don't find the dir, just don't
-        * copy the back ref in.  The link count fixup code will take
-        * care of the rest
-        */
-       dir = read_one_inode(root, key->offset);
-       if (!dir)
-               return -ENOENT;
-
-       inode = read_one_inode(root, key->objectid);
-       if (!inode) {
-               iput(dir);
-               return -EIO;
-       }
-
-       ref_ptr = btrfs_item_ptr_offset(eb, slot);
-       ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
-
-again:
-       ref = (struct btrfs_inode_ref *)ref_ptr;
-
-       namelen = btrfs_inode_ref_name_len(eb, ref);
-       name = kmalloc(namelen, GFP_NOFS);
-       BUG_ON(!name);
-
-       read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
-
-       /* if we already have a perfect match, we're done */
-       if (inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
-                        btrfs_inode_ref_index(eb, ref),
-                        name, namelen)) {
-               goto out;
-       }
-
-       /*
-        * look for a conflicting back reference in the metadata.
-        * if we find one we have to unlink that name of the file
-        * before we add our new link.  Later on, we overwrite any
-        * existing back reference, and we don't want to create
-        * dangling pointers in the directory.
-        */
-
-       if (search_done)
-               goto insert;
+       struct btrfs_dir_item *di;
 
        ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
        if (ret == 0) {
@@ -869,7 +811,7 @@ again:
                 * if so, just jump out, we're done
                 */
                if (key->objectid == key->offset)
-                       goto out_nowrite;
+                       return 1;
 
                /* check all the names in this back reference to see
                 * if they are in the log.  if so, we allow them to stay
@@ -888,7 +830,7 @@ again:
                                           (unsigned long)(victim_ref + 1),
                                           victim_name_len);
 
-                       if (!backref_in_log(log, key, victim_name,
+                       if (!backref_in_log(log_root, key, victim_name,
                                            victim_name_len)) {
                                btrfs_inc_nlink(inode);
                                btrfs_release_path(path);
@@ -907,7 +849,7 @@ again:
                 * NOTE: we have searched root tree and checked the
                 * coresponding ref, it does not need to check again.
                 */
-               search_done = 1;
+               *search_done = 1;
        }
        btrfs_release_path(path);
 
@@ -930,25 +872,99 @@ again:
        }
        btrfs_release_path(path);
 
-insert:
-       /* insert our name */
-       ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,
-                            btrfs_inode_ref_index(eb, ref));
-       BUG_ON(ret);
+       return 0;
+}
+
+/*
+ * replay one inode back reference item found in the log tree.
+ * eb, slot and key refer to the buffer and key found in the log tree.
+ * root is the destination we are replaying into, and path is for temp
+ * use by this function.  (it should be released on return).
+ */
+static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
+                                 struct btrfs_root *root,
+                                 struct btrfs_root *log,
+                                 struct btrfs_path *path,
+                                 struct extent_buffer *eb, int slot,
+                                 struct btrfs_key *key)
+{
+       struct btrfs_inode_ref *ref;
+       struct inode *dir;
+       struct inode *inode;
+       unsigned long ref_ptr;
+       unsigned long ref_end;
+       char *name;
+       int namelen;
+       int ret;
+       int search_done = 0;
+
+       /*
+        * it is possible that we didn't log all the parent directories
+        * for a given inode.  If we don't find the dir, just don't
+        * copy the back ref in.  The link count fixup code will take
+        * care of the rest
+        */
+       dir = read_one_inode(root, key->offset);
+       if (!dir)
+               return -ENOENT;
 
-       btrfs_update_inode(trans, root, inode);
+       inode = read_one_inode(root, key->objectid);
+       if (!inode) {
+               iput(dir);
+               return -EIO;
+       }
 
-out:
-       ref_ptr = (unsigned long)(ref + 1) + namelen;
-       kfree(name);
-       if (ref_ptr < ref_end)
-               goto again;
+       ref_ptr = btrfs_item_ptr_offset(eb, slot);
+       ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
+
+       while (ref_ptr < ref_end) {
+               ref = (struct btrfs_inode_ref *)ref_ptr;
+
+               namelen = btrfs_inode_ref_name_len(eb, ref);
+               name = kmalloc(namelen, GFP_NOFS);
+               BUG_ON(!name);
+
+               read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
+
+               /* if we already have a perfect match, we're done */
+               if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
+                                 btrfs_inode_ref_index(eb, ref),
+                                 name, namelen)) {
+                       /*
+                        * look for a conflicting back reference in the
+                        * metadata. if we find one we have to unlink that name
+                        * of the file before we add our new link.  Later on, we
+                        * overwrite any existing back reference, and we don't
+                        * want to create dangling pointers in the directory.
+                        */
+
+                       if (!search_done) {
+                               ret = __add_inode_ref(trans, root, path, log,
+                                                     dir, inode, key, eb, ref,
+                                                     name, namelen,
+                                                     &search_done);
+                               if (ret == 1)
+                                       goto out;
+                               BUG_ON(ret);
+                       }
+
+                       /* insert our name */
+                       ret = btrfs_add_link(trans, dir, inode, name, namelen,
+                                            0, btrfs_inode_ref_index(eb, ref));
+                       BUG_ON(ret);
+
+                       btrfs_update_inode(trans, root, inode);
+               }
+
+               ref_ptr = (unsigned long)(ref + 1) + namelen;
+               kfree(name);
+       }
 
        /* finally write the back reference in the inode */
        ret = overwrite_item(trans, root, path, eb, slot, key);
        BUG_ON(ret);
 
-out_nowrite:
+out:
        btrfs_release_path(path);
        iput(dir);
        iput(inode);