io_uring: correct check for O_TMPFILE

O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old
check for whether RESOLVE_CACHED can be used would incorrectly think
that O_DIRECTORY could not be used with RESOLVE_CACHED.

Cc: stable@vger.kernel.org # v5.12+
Fixes: 3a81fd0 ("io_uring: enable LOOKUP_CACHED path resolution for filename lookups")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20230807-resolve_cached-o_tmpfile-v3-1-e49323e1ef6f@cyphar.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: cyphar

io_uring/openclose.c

@@ -35,9 +35,11 @@ static bool io_openat_force_async(struct io_open *open)
 {
 	/*
 	 * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
-	 * it'll always -EAGAIN
+	 * it'll always -EAGAIN. Note that we test for __O_TMPFILE because
+	 * O_TMPFILE includes O_DIRECTORY, which isn't a flag we need to force
+	 * async for.
 	 */
-	return open->how.flags & (O_TRUNC | O_CREAT | O_TMPFILE);
+	return open->how.flags & (O_TRUNC | O_CREAT | __O_TMPFILE);
 }
 
 static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)