The old hash function didn't work well for 64-bit block numbers, and
used undefined (negative) shift right behavior. Use the generic
64-bit hash function instead.
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Reported-by: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
---
fs/jbd2/revoke.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index d5e95a1..c6cbaef 100644
--- a/fs/jbd2/revoke.c
+++ b/fs/jbd2/revoke.c
@@ -92,6 +92,7 @@
#include <linux/init.h>
#include <linux/bio.h>
#include <linux/log2.h>
+#include <linux/hash.h>
#endif
static struct kmem_cache *jbd2_revoke_record_cache;
@@ -130,16 +131,9 @@ static void flush_descriptor(journal_t *, struct buffer_head *, int, int);
/* Utility functions to maintain the revoke table */
-/* Borrowed from buffer.c: this is a tried and tested block hash function */
static inline int hash(journal_t *journal, unsigned long long block)
{
- struct jbd2_revoke_table_s *table = journal->j_revoke;
- int hash_shift = table->hash_shift;
- int hash = (int)block ^ (int)((block >> 31) >> 1);
-
- return ((hash << (hash_shift - 6)) ^
- (hash >> 13) ^
- (hash << (hash_shift - 12))) & (table->hash_size - 1);
+ return hash_64(block, journal->j_revoke->hash_shift);
}
static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr,
--
2.1.0
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
