Merge branch 'work.lookup' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull more ->lookup() cleanups from Al Viro:
 "Some ->lookup() instances are still overcomplicating the life
  for themselves, open-coding the stuff that would be handled by
  d_splice_alias() just fine.

  Simplify a couple of such cases caught this cycle and document
  d_splice_alias() intended use"

* 'work.lookup' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  Document d_splice_alias() calling conventions for ->lookup() users.
  simplify btrfs_lookup()
  clean erofs_lookup()

diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 7b7b845c490a4b187183b5acc7dead9e0141c45d..321d74b73937231d0dbf927ec89689082d14fcce 100644 (file)
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -622,3 +622,14 @@ in your dentry operations instead.
        alloc_file_clone(file, flags, ops) does not affect any caller's references.
        On success you get a new struct file sharing the mount/dentry with the
        original, on failure - ERR_PTR().
+--
+[recommended]
+       ->lookup() instances doing an equivalent of
+               if (IS_ERR(inode))
+                       return ERR_CAST(inode);
+               return d_splice_alias(inode, dentry);
+       don't need to bother with the check - d_splice_alias() will do the
+       right thing when given ERR_PTR(...) as inode.  Moreover, passing NULL
+       inode to d_splice_alias() will also do the right thing (equivalent of
+       d_add(dentry, NULL); return NULL;), so that kind of special cases
+       also doesn't need a separate treatment.

diff --git a/drivers/staging/erofs/namei.c b/drivers/staging/erofs/namei.c
index 546a47156101ab73784072c2826be383549c5c23..8cf0617d4ea01108c961c6fd3099d7752fdc4c31 100644 (file)
--- a/drivers/staging/erofs/namei.c
+++ b/drivers/staging/erofs/namei.c
@@ -223,18 +223,13 @@ static struct dentry *erofs_lookup(struct inode *dir,
        if (err == -ENOENT) {
                /* negative dentry */
                inode = NULL;
-               goto negative_out;
-       } else if (unlikely(err))
-               return ERR_PTR(err);
-
-       debugln("%s, %s (nid %llu) found, d_type %u", __func__,
-               dentry->d_name.name, nid, d_type);
-
-       inode = erofs_iget(dir->i_sb, nid, d_type == EROFS_FT_DIR);
-       if (IS_ERR(inode))
-               return ERR_CAST(inode);
-
-negative_out:
+       } else if (unlikely(err)) {
+               inode = ERR_PTR(err);
+       } else {
+               debugln("%s, %s (nid %llu) found, d_type %u", __func__,
+                       dentry->d_name.name, nid, d_type);
+               inode = erofs_iget(dir->i_sb, nid, d_type == EROFS_FT_DIR);
+       }
        return d_splice_alias(inode, dentry);
 }
 

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f22f77172c5ff5299b37aa8e10be770929c61a44..181c58b231103e5a7381be49cddc10c2faf3fdc5 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5764,16 +5764,10 @@ static int btrfs_dentry_delete(const struct dentry *dentry)
 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
                                   unsigned int flags)
 {
-       struct inode *inode;
-
-       inode = btrfs_lookup_dentry(dir, dentry);
-       if (IS_ERR(inode)) {
-               if (PTR_ERR(inode) == -ENOENT)
-                       inode = NULL;
-               else
-                       return ERR_CAST(inode);
-       }
+       struct inode *inode = btrfs_lookup_dentry(dir, dentry);
 
+       if (inode == ERR_PTR(-ENOENT))
+               inode = NULL;
        return d_splice_alias(inode, dentry);
 }