io_uring: correct check for O_TMPFILE

Commit 72dbde0 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

io_uring/openclose.c

@@ -110,9 +110,11 @@ int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
 	if (issue_flags & IO_URING_F_NONBLOCK) {
 		/*
 		 * 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.
 		 */
-		if (open->how.flags & (O_TRUNC | O_CREAT | O_TMPFILE))
+		if (open->how.flags & (O_TRUNC | O_CREAT | __O_TMPFILE))
 			return -EAGAIN;
 		op.lookup_flags |= LOOKUP_CACHED;
 		op.open_flag |= O_NONBLOCK;