Release fstests v2025.05.11
f2fs/012: test red heart lookup
As Han Qi reported in bugzilla [1], commit 5c26d2f1d3f5 ("unicode: Don't
special case ignorable code points") changes logic to handle ignorable
code points, when we handle filename which has special unicode charactor
like red heart ❤️, utf8_casefold() may return different length than in the
past, result in that f2fs cacluates hash code incorreclty, eventually,
filename w/ special unicode charactor will not be found w/ the wrong hash
code.
f2fs has introduced a linear lookup fallback w/ commit 91b587ba79e1
("f2fs: Introduce linear search for dentries"), once hash-based lookup
fails, it tries linear lookup as a fallback.
This patch can help to check whether linear lookup fallback works well
or not.
Firstly, we use below testcase to check how hash code changes:
mkfs.f2fs -f -O casefold -C utf8 /dev/vda
mount /dev/vda /mnt/f2fs
mkdir /mnt/f2fs/dir/
f2fs_io setflags casefold /mnt/f2fs/dir
touch /mnt/f2fs/dir/$'\u2764\ufe0f'
umount /mnt/f2fs
dump.f2fs -i 4 -d 3 /dev/vda
dump.f2fs -b $blkaddr_of_dir -d 3 /dev/vda
w/o ("unicode: Don't special case ignorable code points")
[dump_dirent: 991] bitmap pos[0x2] name[❤️] len[0x6] hash[0x19dd7132] ino[0x5] type[0x1]
[dump_dirent: 998] name(hex)[0xe2 0x9d 0xa4 0xef 0xb8 0x8f 0x0]
w/ ("unicode: Don't special case ignorable code points")
[dump_dirent: 991] bitmap pos[0x2] name[❤️] len[0x6] hash[0x9a2ea068] ino[0x5] type[0x1]
[dump_dirent: 998] name(hex)[0xe2 0x9d 0xa4 0xef 0xb8 0x8f 0x0]
Correct hash code: 0x19dd7132
Wrong hash code: 0x9a2ea068
So, we can test as below:
1. create file w/ red heart as its filename
2. inject wrong hash code to the file
3. disable linear lookup, expect lookup failure
4. enable linear lookup, expect lookup succeed
[1] https://bugzilla.kernel.org/show_bug.cgi?id=219586
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Daniel Lee <chullee@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>
2 files changed
