lookup_one_len_unlocked(): use lookup_dcache() (d6d95ded) · Commits · 戴 / test

No need to lock parent just because of ->d_revalidate() on child; contrary to the stale comment, lookup_dcache() *can* be used without locking the parent. Result can be moved as soon as we return, of course, but the same is true for lookup_one_len_unlocked() itself. Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

+1 −11

Original line number	Diff line number	Diff line
		@@ -1444,8 +1444,6 @@ static int follow_dotdot(struct nameidata *nd)
		* This looks up the name in dcache, possibly revalidates the old dentry and
		* allocates a new one if not found or not valid. In the need_lookup argument
		* returns whether i_op->lookup is necessary.
		*
		* dir->d_inode->i_mutex must be held
		*/
		static struct dentry lookup_dcache(struct qstr name, struct dentry *dir,
		unsigned int flags)
		@@ -2351,15 +2349,7 @@ struct dentry lookup_one_len_unlocked(const char name,
		if (err)
		return ERR_PTR(err);

		/*
		* __d_lookup() is used to try to get a quick answer and avoid the
		* mutex. A false-negative does no harm.
		*/
		ret = __d_lookup(base, &this);
		if (ret && unlikely(ret->d_flags & DCACHE_OP_REVALIDATE)) {
		dput(ret);
		ret = NULL;
		}
		ret = lookup_dcache(&this, base, 0);
		if (ret)
		return ret;

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