anon_inode: rework assertions

Making anonymous inodes regular files comes with a lot of risk and
regression potential as evidenced by a recent hickup in io_uring. We're
better of continuing to not have them be regular files. Since we have
S_ANON_INODE we can port all of our assertions easily.

Link: https://lore.kernel.org/[email protected]
Fixes: cfd86ef7e8e7 ("anon_inode: use a proper mode internally")
Acked-by: Jens Axboe <[email protected]>
Cc: [email protected]
Reported-by: Jens Axboe <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

1 files changed, 3 insertions, 5 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 9ea0ecc325a8..6f487fc6be34 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1649,12 +1649,10 @@ struct inode *alloc_anon_inode(struct super_block *s)
 	 */
 	inode->i_state = I_DIRTY;
 	/*
-	 * Historically anonymous inodes didn't have a type at all and
-	 * userspace has come to rely on this. Internally they're just
-	 * regular files but S_IFREG is masked off when reporting
-	 * information to userspace.
+	 * Historically anonymous inodes don't have a type at all and
+	 * userspace has come to rely on this.
 	 */
-	inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
+	inode->i_mode = S_IRUSR | S_IWUSR;
 	inode->i_uid = current_fsuid();
 	inode->i_gid = current_fsgid();
 	inode->i_flags |= S_PRIVATE | S_ANON_INODE;