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| author | Theodore Ts'o <tytso@mit.edu> | 2014-10-30 15:53:17 +0100 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-10-30 15:53:17 +0100 |
| commit | d48458d4a768cece43f80a081a26cf912877da9c (patch) | |
| tree | e713d0ba1a20da5561f181cd9a17fe1e9cfc550e | |
| parent | ext4: prevent bugon on race between write/fcntl (diff) | |
| download | linux-d48458d4a768cece43f80a081a26cf912877da9c.tar.xz linux-d48458d4a768cece43f80a081a26cf912877da9c.zip | |
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>
| -rw-r--r-- | fs/jbd2/revoke.c | 10 |
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, |