Unverified Commit 3661a788 authored by NeilBrown's avatar NeilBrown Committed by Christian Brauner
Browse files

VFS: tidy up do_unlinkat() 



The simplification of locking in the previous patch opens up some room
for tidying up do_unlinkat()

- change all "exit" labels to describe what will happen at the label.
- always goto an exit label on an error - unwrap the "if (!IS_ERR())" branch.
- Move the "slashes" handing inline, but mark it as unlikely()
- simplify use of the "inode" variable - we no longer need to test for NULL.

Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarNeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-4-neilb@ownmail.net


Tested-by: default avatar <syzbot@syzkaller.appspotmail.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 4037d966

fs/namei.c

+26 −29
Original line number Diff line number Diff line
@@ -4755,65 +4755,62 @@ int do_unlinkat(int dfd, struct filename *name) 
	struct path path;

	struct qstr last;

	int type;

	struct inode *inode = NULL;

	struct inode *inode;

	struct inode *delegated_inode = NULL;

	unsigned int lookup_flags = 0;

retry:

	error = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);

	if (error)

		goto exit1;

		goto exit_putname;



	error = -EISDIR;

	if (type != LAST_NORM)

		goto exit2;

		goto exit_path_put;



	error = mnt_want_write(path.mnt);

	if (error)

		goto exit2;

		goto exit_path_put;

retry_deleg:

	dentry = start_dirop(path.dentry, &last, lookup_flags);

	error = PTR_ERR(dentry);

	if (!IS_ERR(dentry)) {

	if (IS_ERR(dentry))

		goto exit_drop_write;



	/* Why not before? Because we want correct error value */

		if (last.name[last.len])

			goto slashes;

	if (unlikely(last.name[last.len])) {

		if (d_is_dir(dentry))

			error = -EISDIR;

		else

			error = -ENOTDIR;

		end_dirop(dentry);

		goto exit_drop_write;

	}

	inode = dentry->d_inode;

	ihold(inode);

	error = security_path_unlink(&path, dentry);

	if (error)

			goto exit3;

		goto exit_end_dirop;

	error = vfs_unlink(mnt_idmap(path.mnt), path.dentry->d_inode,

			   dentry, &delegated_inode);

exit3:

exit_end_dirop:

	end_dirop(dentry);

	}

	if (inode)

	iput(inode);	/* truncate the inode here */

	inode = NULL;

	if (delegated_inode) {

		error = break_deleg_wait(&delegated_inode);

		if (!error)

			goto retry_deleg;

	}

exit_drop_write:

	mnt_drop_write(path.mnt);

exit2:

exit_path_put:

	path_put(&path);

	if (retry_estale(error, lookup_flags)) {

		lookup_flags |= LOOKUP_REVAL;

		inode = NULL;

		goto retry;

	}

exit1:

exit_putname:

	putname(name);

	return error;



slashes:

	if (d_is_dir(dentry))

		error = -EISDIR;

	else

		error = -ENOTDIR;

	goto exit3;

}



SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)