| Message ID | 20200316090512.21519-1-nborisov@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs-progs: Fix xxhash on big endian machines | expand |
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
On Mon, Mar 16, 2020 at 11:05:12AM +0200, Nikolay Borisov wrote: > xxhash's state and results are always in little, but in progs after the > hash was calculated it was copied to the final buffer via memcpy, > meaning it'd be parsed as a big endian number on big endian machines. > This is incompatible with the kernel implementation of xxhash which > results in erroneous "checksum didn't match" errors on mount. > > Fix it by using put_unaligned_le64 which always ensures the resulting > checksum will be copied in little endian format as the kernel expects > it. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206835 > Fixes: f070ece2e98f ("btrfs-progs: add xxhash64 to mkfs") > Signed-off-by: Nikolay Borisov <nborisov@suse.com> Added to devel, thanks.
On Mon, Mar 16, 2020 at 11:05:12AM +0200, Nikolay Borisov wrote: > xxhash's state and results are always in little, but in progs after the > hash was calculated it was copied to the final buffer via memcpy, > meaning it'd be parsed as a big endian number on big endian machines. > This is incompatible with the kernel implementation of xxhash which > results in erroneous "checksum didn't match" errors on mount. > > Fix it by using put_unaligned_le64 which always ensures the resulting > checksum will be copied in little endian format as the kernel expects > it. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206835 > Fixes: f070ece2e98f ("btrfs-progs: add xxhash64 to mkfs") > Signed-off-by: Nikolay Borisov <nborisov@suse.com> > --- > crypto/hash.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/crypto/hash.c b/crypto/hash.c > index 48623c798739..4009e84e8b2c 100644 > --- a/crypto/hash.c > +++ b/crypto/hash.c > @@ -19,12 +19,7 @@ int hash_xxhash(const u8 *buf, size_t length, u8 *out) > XXH64_hash_t hash; > > hash = XXH64(buf, length, 0); > - /* > - * NOTE: we're not taking the canonical form here but the plain hash to > - * be compatible with the kernel implementation! > - */ > - memcpy(out, &hash, 8); > - > + put_unaligned_le64(&hash, out); This does not work, the test mkfs/019 fails.
diff --git a/crypto/hash.c b/crypto/hash.c index 48623c798739..4009e84e8b2c 100644 --- a/crypto/hash.c +++ b/crypto/hash.c @@ -19,12 +19,7 @@ int hash_xxhash(const u8 *buf, size_t length, u8 *out) XXH64_hash_t hash; hash = XXH64(buf, length, 0); - /* - * NOTE: we're not taking the canonical form here but the plain hash to - * be compatible with the kernel implementation! - */ - memcpy(out, &hash, 8); - + put_unaligned_le64(&hash, out); return 0; }
xxhash's state and results are always in little, but in progs after the hash was calculated it was copied to the final buffer via memcpy, meaning it'd be parsed as a big endian number on big endian machines. This is incompatible with the kernel implementation of xxhash which results in erroneous "checksum didn't match" errors on mount. Fix it by using put_unaligned_le64 which always ensures the resulting checksum will be copied in little endian format as the kernel expects it. Link: https://bugzilla.kernel.org/show_bug.cgi?id=206835 Fixes: f070ece2e98f ("btrfs-progs: add xxhash64 to mkfs") Signed-off-by: Nikolay Borisov <nborisov@suse.com> --- crypto/hash.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) -- 2.17.1