Found by syzbot (https://syzkaller.appspot.com/bug?extid=9177d065333561cd6fd0):
EXT4-fs (loop0): encrypted files will use data=ordered instead of data journaling mode EXT4-fs (loop0): 1 truncate cleaned up EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none. fscrypt: AES-256-CTS-CBC using implementation "cts-cbc-aes-aesni" ------------[ cut here ]------------ WARNING: CPU: 1 PID: 4245 at fs/crypto/fname.c:567 fscrypt_fname_siphash+0xb9/0xf0 Modules linked in: CPU: 1 PID: 4245 Comm: syz-executor375 Not tainted 6.1.116-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:fscrypt_fname_siphash+0xb9/0xf0 fs/crypto/fname.c:567 Call Trace: <TASK> __ext4fs_dirhash+0xdd2/0x14c0 fs/ext4/hash.c:268 ext4fs_dirhash+0x1b8/0x320 fs/ext4/hash.c:322 htree_dirblock_to_tree+0x723/0x10d0 fs/ext4/namei.c:1125 ext4_htree_fill_tree+0x73d/0x13f0 fs/ext4/namei.c:1220 ext4_dx_readdir fs/ext4/dir.c:605 [inline] ext4_readdir+0x2e87/0x3880 fs/ext4/dir.c:142 iterate_dir+0x224/0x560 __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 </TASK>
These patches address a warning encountered when mounting ext4 filesystems with the default hash version set to SIPHASH while the casefold feature is not enabled. The warning occurs due to incorrect error handling and setup of the default hash version.
[PATCH 1/3 ] ext4: factor out ext4_hash_info_init() Simplifies the ext4 filesystem setup by factoring out the ext4_hash_info_init function, with no functional change.
[PATCH 2/3] ext4: filesystems without casefold feature cannot be mounted with siphash Ensures that ext4 filesystems with the default hash set to SIPHASH cannot be mounted if the casefold feature is not enabled.
[PATCH 3/3] ext4: fix error message when rejecting the default hash Corrects the error message logic for rejecting filesystems with the default SIPHASH hash version, ensuring the error message doesn't incorrectly reference the casefold setup. Also moves the check to ext4_hash_info_init to ensure consistency.