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

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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()
This commit is contained in:
Linus Torvalds 2018-10-25 12:55:31 -07:00
commit 4ba9628fe5
3 changed files with 21 additions and 21 deletions
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11
Documentation/filesystems/porting
View File

@ -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.

19
drivers/staging/erofs/namei.c
View File

@ -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);
}

12
fs/btrfs/inode.c
View File

@ -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);
}