git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/nocow_locking.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BCACHEFS_NOCOW_LOCKING_H
   3 #define _BCACHEFS_NOCOW_LOCKING_H
   4
   5 #include "bcachefs_format.h"
   6 #include "two_state_shared_lock.h"
   7
   8 #include <linux/hash.h>
   9
  10 #define BUCKET_NOCOW_LOCKS_BITS         10
  11 #define BUCKET_NOCOW_LOCKS              (1U << BUCKET_NOCOW_LOCKS_BITS)
  12
  13 struct bucket_nocow_lock_table {
  14         two_state_lock_t                l[BUCKET_NOCOW_LOCKS];
  15 };
  16
  17 #define BUCKET_NOCOW_LOCK_UPDATE        (1 << 0)
  18
  19 static inline two_state_lock_t *bucket_nocow_lock(struct bucket_nocow_lock_table *t,
  20                                                   struct bpos bucket)
  21 {
  22         u64 dev_bucket = bucket.inode << 56 | bucket.offset;
  23         unsigned h = hash_64(dev_bucket, BUCKET_NOCOW_LOCKS_BITS);
  24
  25         return t->l + (h & (BUCKET_NOCOW_LOCKS - 1));
  26 }
  27
  28 static inline bool bch2_bucket_nocow_is_locked(struct bucket_nocow_lock_table *t,
  29                                                struct bpos bucket)
  30 {
  31         two_state_lock_t *l = bucket_nocow_lock(t, bucket);
  32
  33         return atomic_long_read(&l->v) != 0;
  34 }
  35
  36 static inline void bch2_bucket_nocow_unlock(struct bucket_nocow_lock_table *t,
  37                                             struct bpos bucket, int flags)
  38 {
  39         two_state_lock_t *l = bucket_nocow_lock(t, bucket);
  40
  41         bch2_two_state_unlock(l, flags & BUCKET_NOCOW_LOCK_UPDATE);
  42 }
  43
  44 void __bch2_bucket_nocow_lock(struct bucket_nocow_lock_table *, two_state_lock_t *, int);
  45
  46 static inline void bch2_bucket_nocow_lock(struct bucket_nocow_lock_table *t,
  47                                           struct bpos bucket, int flags)
  48 {
  49         two_state_lock_t *l = bucket_nocow_lock(t, bucket);
  50
  51         if (!bch2_two_state_trylock(l, flags & BUCKET_NOCOW_LOCK_UPDATE))
  52                 __bch2_bucket_nocow_lock(t, l, flags);
  53 }
  54
  55 #endif /* _BCACHEFS_NOCOW_LOCKING_H */