diff options
| -rw-r--r-- | fs/ceph/ceph_fs.c | 93 | ||||
| -rw-r--r-- | fs/ceph/ceph_fs.h | 2 |
2 files changed, 71 insertions, 24 deletions
diff --git a/fs/ceph/ceph_fs.c b/fs/ceph/ceph_fs.c index a950b4083577..b3ecf1b07521 100644 --- a/fs/ceph/ceph_fs.c +++ b/fs/ceph/ceph_fs.c @@ -73,32 +73,79 @@ int ceph_caps_for_mode(int mode) return 0; } -/* Name hashing routines. Initial hash value */ -/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */ -#define ceph_init_name_hash() 0 - -/* partial hash update function. Assume roughly 4 bits per character */ -static unsigned long ceph_partial_name_hash(unsigned long c, - unsigned long prevhash) -{ - return (prevhash + (c << 4) + (c >> 4)) * 11; -} - /* - * Finally: cut down the number of bits to a int value (and try to avoid - * losing bits) + * Robert Jenkin's hash function. + * http://burtleburtle.net/bob/hash/evahash.html + * This is in the public domain. */ -static unsigned long ceph_end_name_hash(unsigned long hash) -{ - return hash & 0xffffffff; -} +#define mix(a, b, c) \ + do { \ + a = a - b; a = a - c; a = a ^ (c >> 13); \ + b = b - c; b = b - a; b = b ^ (a << 8); \ + c = c - a; c = c - b; c = c ^ (b >> 13); \ + a = a - b; a = a - c; a = a ^ (c >> 12); \ + b = b - c; b = b - a; b = b ^ (a << 16); \ + c = c - a; c = c - b; c = c ^ (b >> 5); \ + a = a - b; a = a - c; a = a ^ (c >> 3); \ + b = b - c; b = b - a; b = b ^ (a << 10); \ + c = c - a; c = c - b; c = c ^ (b >> 15); \ + } while (0) -/* Compute the hash for a name string. */ -unsigned int ceph_full_name_hash(const char *name, unsigned int len) +unsigned int ceph_full_name_hash(const char *str, unsigned int length) { - unsigned long hash = ceph_init_name_hash(); - while (len--) - hash = ceph_partial_name_hash(*name++, hash); - return ceph_end_name_hash(hash); + const unsigned char *k = (const unsigned char *)str; + __u32 a, b, c; /* the internal state */ + __u32 len; /* how many key bytes still need mixing */ + + /* Set up the internal state */ + len = length; + a = 0x9e3779b9; /* the golden ratio; an arbitrary value */ + b = a; + c = 0; /* variable initialization of internal state */ + + /* handle most of the key */ + while (len >= 12) { + a = a + (k[0] + ((__u32)k[1] << 8) + ((__u32)k[2] << 16) + + ((__u32)k[3] << 24)); + b = b + (k[4] + ((__u32)k[5] << 8) + ((__u32)k[6] << 16) + + ((__u32)k[7] << 24)); + c = c + (k[8] + ((__u32)k[9] << 8) + ((__u32)k[10] << 16) + + ((__u32)k[11] << 24)); + mix(a, b, c); + k = k + 12; + len = len - 12; + } + + /* handle the last 11 bytes */ + c = c + length; + switch (len) { /* all the case statements fall through */ + case 11: + c = c + ((__u32)k[10] << 24); + case 10: + c = c + ((__u32)k[9] << 16); + case 9: + c = c + ((__u32)k[8] << 8); + /* the first byte of c is reserved for the length */ + case 8: + b = b + ((__u32)k[7] << 24); + case 7: + b = b + ((__u32)k[6] << 16); + case 6: + b = b + ((__u32)k[5] << 8); + case 5: + b = b + k[4]; + case 4: + a = a + ((__u32)k[3] << 24); + case 3: + a = a + ((__u32)k[2] << 16); + case 2: + a = a + ((__u32)k[1] << 8); + case 1: + a = a + k[0]; + /* case 0: nothing left to add */ + } + mix(a, b, c); + + return c; } diff --git a/fs/ceph/ceph_fs.h b/fs/ceph/ceph_fs.h index ae523828c538..25fc537f4140 100644 --- a/fs/ceph/ceph_fs.h +++ b/fs/ceph/ceph_fs.h @@ -38,7 +38,7 @@ #define CEPH_OSD_PROTOCOL 7 /* cluster internal */ #define CEPH_MDS_PROTOCOL 9 /* cluster internal */ #define CEPH_MON_PROTOCOL 5 /* cluster internal */ -#define CEPH_OSDC_PROTOCOL 21 /* server/client */ +#define CEPH_OSDC_PROTOCOL 22 /* server/client */ #define CEPH_MDSC_PROTOCOL 29 /* server/client */ #define CEPH_MONC_PROTOCOL 15 /* server/client */ |