filehash.c

   1 #include <stdlib.h>
   2 #include <assert.h>
   3
   4 #include "fio.h"
   5 #include "flist.h"
   6 #include "crc/crc16.h"
   7
   8 #include "spinlock.h"
   9
  10 #define HASH_BUCKETS    512
  11 #define HASH_MASK       (HASH_BUCKETS - 1)
  12
  13 unsigned int file_hash_size = HASH_BUCKETS * sizeof(struct flist_head);
  14
  15 static struct flist_head *file_hash;
  16 static struct fio_spinlock *hash_lock;
  17
  18 static unsigned short hash(const char *name)
  19 {
  20         return crc16((const unsigned char *) name, strlen(name)) & HASH_MASK;
  21 }
  22
  23 void remove_file_hash(struct fio_file *f)
  24 {
  25         fio_spin_lock(hash_lock);
  26
  27         if (f->flags & FIO_FILE_HASHED) {
  28                 assert(!flist_empty(&f->hash_list));
  29                 flist_del_init(&f->hash_list);
  30                 f->flags &= ~FIO_FILE_HASHED;
  31         }
  32
  33         fio_spin_unlock(hash_lock);
  34 }
  35
  36 static struct fio_file *__lookup_file_hash(const char *name)
  37 {
  38         struct flist_head *bucket = &file_hash[hash(name)];
  39         struct flist_head *n;
  40
  41         flist_for_each(n, bucket) {
  42                 struct fio_file *f = flist_entry(n, struct fio_file, hash_list);
  43
  44                 if (!strcmp(f->file_name, name)) {
  45                         assert(f->fd != -1);
  46                         return f;
  47                 }
  48         }
  49
  50         return NULL;
  51 }
  52
  53 struct fio_file *lookup_file_hash(const char *name)
  54 {
  55         struct fio_file *f;
  56
  57         fio_spin_lock(hash_lock);
  58         f = __lookup_file_hash(name);
  59         fio_spin_unlock(hash_lock);
  60         return f;
  61 }
  62
  63 struct fio_file *add_file_hash(struct fio_file *f)
  64 {
  65         struct fio_file *alias;
  66
  67         if (f->flags & FIO_FILE_HASHED)
  68                 return NULL;
  69
  70         INIT_FLIST_HEAD(&f->hash_list);
  71
  72         fio_spin_lock(hash_lock);
  73
  74         alias = __lookup_file_hash(f->file_name);
  75         if (!alias) {
  76                 f->flags |= FIO_FILE_HASHED;
  77                 flist_add_tail(&f->hash_list, &file_hash[hash(f->file_name)]);
  78         }
  79
  80         fio_spin_unlock(hash_lock);
  81         return alias;
  82 }
  83
  84 void file_hash_exit(void)
  85 {
  86         unsigned int i, has_entries = 0;
  87
  88         fio_spin_lock(hash_lock);
  89         for (i = 0; i < HASH_BUCKETS; i++)
  90                 has_entries += !flist_empty(&file_hash[i]);
  91
  92         file_hash = NULL;
  93         fio_spin_unlock(hash_lock);
  94
  95         if (has_entries)
  96                 log_err("fio: file hash not empty on exit\n");
  97
  98         fio_spinlock_remove(hash_lock);
  99         hash_lock = NULL;
 100 }
 101
 102 void file_hash_init(void *ptr)
 103 {
 104         unsigned int i;
 105
 106         file_hash = ptr;
 107         for (i = 0; i < HASH_BUCKETS; i++)
 108                 INIT_FLIST_HEAD(&file_hash[i]);
 109
 110         hash_lock = fio_spinlock_init();
 111 }