btrfs: send: directly return from did_overwrite_ref() and simplify it

There are no resources to release before did_overwrite_ref() returns, so
we don't really need the 'out' label and jumping to it when conditions are
met - we can directly return and get rid of the label and jumps. Also we
can deal with -ENOENT and other errors in a single if-else logic, as it's
more straightforward.

This helps the next patch in the series to be more simple as well.

This patch is part of a larger patchset and the changelog of the last
patch in the series contains a sample performance test and results.
The patches that comprise the patchset are the following:

  btrfs: send: directly return from did_overwrite_ref() and simplify it
  btrfs: send: avoid unnecessary generation search at did_overwrite_ref()
  btrfs: send: directly return from will_overwrite_ref() and simplify it
  btrfs: send: avoid extra b+tree searches when checking reference overrides
  btrfs: send: remove send_progress argument from can_rmdir()
  btrfs: send: avoid duplicated orphan dir allocation and initialization
  btrfs: send: avoid unnecessary orphan dir rbtree search at can_rmdir()
  btrfs: send: reduce searches on parent root when checking if dir can be removed
  btrfs: send: iterate waiting dir move rbtree only once when processing refs
  btrfs: send: initialize all the red black trees earlier
  btrfs: send: genericize the backref cache to allow it to be reused
  btrfs: adapt lru cache to allow for 64 bits keys on 32 bits systems
  btrfs: send: cache information about created directories
  btrfs: allow a generation number to be associated with lru cache entries
  btrfs: add an api to delete a specific entry from the lru cache
  btrfs: send: use the lru cache to implement the name cache
  btrfs: send: update size of roots array for backref cache entries
  btrfs: send: cache utimes operations for directories if possible

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 1c2dc8e0323d48a7ad7700bff78126aedf0d005b..c77508b7ed68991223d7a36863bcbd770e4f40ee 100644 (file)
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -2192,48 +2192,44 @@ static int did_overwrite_ref(struct send_ctx *sctx,
                            u64 ino, u64 ino_gen,
                            const char *name, int name_len)
 {
-       int ret = 0;
+       int ret;
        u64 gen;
        u64 ow_inode;
 
        if (!sctx->parent_root)
-               goto out;
+               return 0;
 
        ret = is_inode_existent(sctx, dir, dir_gen);
        if (ret <= 0)
-               goto out;
+               return ret;
 
        if (dir != BTRFS_FIRST_FREE_OBJECTID) {
                ret = get_inode_gen(sctx->send_root, dir, &gen);
-               if (ret < 0 && ret != -ENOENT)
-                       goto out;
-               if (ret) {
-                       ret = 0;
-                       goto out;
-               }
+               if (ret == -ENOENT)
+                       return 0;
+               else if (ret < 0)
+                       return ret;
+
                if (gen != dir_gen)
-                       goto out;
+                       return 0;
        }
 
        /* check if the ref was overwritten by another ref */
        ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
                                    &ow_inode);
-       if (ret < 0 && ret != -ENOENT)
-               goto out;
-       if (ret) {
+       if (ret == -ENOENT) {
                /* was never and will never be overwritten */
-               ret = 0;
-               goto out;
+               return 0;
+       } else if (ret < 0) {
+               return ret;
        }
 
        ret = get_inode_gen(sctx->send_root, ow_inode, &gen);
        if (ret < 0)
-               goto out;
+               return ret;
 
-       if (ow_inode == ino && gen == ino_gen) {
-               ret = 0;
-               goto out;
-       }
+       if (ow_inode == ino && gen == ino_gen)
+               return 0;
 
        /*
         * We know that it is or will be overwritten. Check this now.
@@ -2244,12 +2240,9 @@ static int did_overwrite_ref(struct send_ctx *sctx,
        if ((ow_inode < sctx->send_progress) ||
            (ino != sctx->cur_ino && ow_inode == sctx->cur_ino &&
             gen == sctx->cur_inode_gen))
-               ret = 1;
-       else
-               ret = 0;
+               return 1;
 
-out:
-       return ret;
+       return 0;
 }
 
 /*