VFS: Combine inode checks with d_is_negative() and d_is_positive() in pathwalk (698934df) · Commits · 戴 / test

Where we have: if (!dentry->d_inode || d_is_negative(dentry)) { type constructions in pathwalk we should be able to eliminate the check of d_inode and rely solely on the result of d_is_negative() or d_is_positive(). What we do have to take care to do is to read d_inode after calling a d_is_xxx() typecheck function to get the barriering right. Signed-off-by:

David Howells <dhowells@redhat.com> Signed-off-by:

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

fs/namei.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1585,7 +1585,7 @@ static inline int walk_component(struct nameidata nd, struct path path,
		inode = path->dentry->d_inode;
		}
		err = -ENOENT;
		if (!inode \|\| d_is_negative(path->dentry))
		if (d_is_negative(path->dentry))
		goto out_path_put;

		if (should_follow_link(path->dentry, follow)) {
		@@ -2310,7 +2310,7 @@ mountpoint_last(struct nameidata nd, struct path path)
		mutex_unlock(&dir->d_inode->i_mutex);

		done:
		if (!dentry->d_inode \|\| d_is_negative(dentry)) {
		if (d_is_negative(dentry)) {
		error = -ENOENT;
		dput(dentry);
		goto out;
		@@ -3038,7 +3038,7 @@ retry_lookup:
		finish_lookup:
		/* we _can_ be in RCU mode here */
		error = -ENOENT;
		if (!inode \|\| d_is_negative(path->dentry)) {
		if (d_is_negative(path->dentry)) {
		path_to_nameidata(path, nd);
		goto out;
		}

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