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authorTheodore Ts'o <tytso@mit.edu>2014-10-30 17:53:17 +0300
committerTheodore Ts'o <tytso@mit.edu>2014-10-30 17:53:17 +0300
commitd48458d4a768cece43f80a081a26cf912877da9c (patch)
treee713d0ba1a20da5561f181cd9a17fe1e9cfc550e /fs
parenta41537e69b4aa43f0fea02498c2595a81267383b (diff)
downloadlinux-d48458d4a768cece43f80a081a26cf912877da9c.tar.xz
jbd2: use a better hash function for the revoke table
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@mit.edu> Reported-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/jbd2/revoke.c10
1 files changed, 2 insertions, 8 deletions
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index d5e95a175c92..c6cbaef2bda1 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,