fs/xfs/libxfs/xfs_refcount.h

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2016 Oracle.  All Rights Reserved.
   4  * Author: Darrick J. Wong <darrick.wong@oracle.com>
   5  */
   6 #ifndef __XFS_REFCOUNT_H__
   7 #define __XFS_REFCOUNT_H__
   8
   9 struct xfs_trans;
  10 struct xfs_mount;
  11 struct xfs_perag;
  12 struct xfs_btree_cur;
  13 struct xfs_bmbt_irec;
  14 struct xfs_refcount_irec;
  15
  16 extern int xfs_refcount_lookup_le(struct xfs_btree_cur *cur,
  17                 enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
  18 extern int xfs_refcount_lookup_ge(struct xfs_btree_cur *cur,
  19                 enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
  20 extern int xfs_refcount_lookup_eq(struct xfs_btree_cur *cur,
  21                 enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
  22 extern int xfs_refcount_get_rec(struct xfs_btree_cur *cur,
  23                 struct xfs_refcount_irec *irec, int *stat);
  24
  25 static inline uint32_t
  26 xfs_refcount_encode_startblock(
  27         xfs_agblock_t           startblock,
  28         enum xfs_refc_domain    domain)
  29 {
  30         uint32_t                start;
  31
  32         /*
  33          * low level btree operations need to handle the generic btree range
  34          * query functions (which set rc_domain == -1U), so we check that the
  35          * domain is /not/ shared.
  36          */
  37         start = startblock & ~XFS_REFC_COWFLAG;
  38         if (domain != XFS_REFC_DOMAIN_SHARED)
  39                 start |= XFS_REFC_COWFLAG;
  40
  41         return start;
  42 }
  43
  44 enum xfs_refcount_intent_type {
  45         XFS_REFCOUNT_INCREASE = 1,
  46         XFS_REFCOUNT_DECREASE,
  47         XFS_REFCOUNT_ALLOC_COW,
  48         XFS_REFCOUNT_FREE_COW,
  49 };
  50
  51 #define XFS_REFCOUNT_INTENT_STRINGS \
  52         { XFS_REFCOUNT_INCREASE,        "incr" }, \
  53         { XFS_REFCOUNT_DECREASE,        "decr" }, \
  54         { XFS_REFCOUNT_ALLOC_COW,       "alloc_cow" }, \
  55         { XFS_REFCOUNT_FREE_COW,        "free_cow" }
  56
  57 struct xfs_refcount_intent {
  58         struct list_head                        ri_list;
  59         struct xfs_group                        *ri_group;
  60         enum xfs_refcount_intent_type           ri_type;
  61         xfs_extlen_t                            ri_blockcount;
  62         xfs_fsblock_t                           ri_startblock;
  63 };
  64
  65 /* Check that the refcount is appropriate for the record domain. */
  66 static inline bool
  67 xfs_refcount_check_domain(
  68         const struct xfs_refcount_irec  *irec)
  69 {
  70         if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
  71                 return false;
  72         if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
  73                 return false;
  74         return true;
  75 }
  76
  77 void xfs_refcount_increase_extent(struct xfs_trans *tp,
  78                 struct xfs_bmbt_irec *irec);
  79 void xfs_refcount_decrease_extent(struct xfs_trans *tp,
  80                 struct xfs_bmbt_irec *irec);
  81
  82 extern int xfs_refcount_finish_one(struct xfs_trans *tp,
  83                 struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);
  84
  85 extern int xfs_refcount_find_shared(struct xfs_btree_cur *cur,
  86                 xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
  87                 xfs_extlen_t *flen, bool find_end_of_shared);
  88
  89 void xfs_refcount_alloc_cow_extent(struct xfs_trans *tp, xfs_fsblock_t fsb,
  90                 xfs_extlen_t len);
  91 void xfs_refcount_free_cow_extent(struct xfs_trans *tp, xfs_fsblock_t fsb,
  92                 xfs_extlen_t len);
  93 extern int xfs_refcount_recover_cow_leftovers(struct xfs_mount *mp,
  94                 struct xfs_perag *pag);
  95
  96 /*
  97  * While we're adjusting the refcounts records of an extent, we have
  98  * to keep an eye on the number of extents we're dirtying -- run too
  99  * many in a single transaction and we'll exceed the transaction's
 100  * reservation and crash the fs.  Each record adds 12 bytes to the
 101  * log (plus any key updates) so we'll conservatively assume 32 bytes
 102  * per record.  We must also leave space for btree splits on both ends
 103  * of the range and space for the CUD and a new CUI.
 104  *
 105  * Each EFI that we attach to the transaction is assumed to consume ~32 bytes.
 106  * This is a low estimate for an EFI tracking a single extent (16 bytes for the
 107  * EFI header, 16 for the extent, and 12 for the xlog op header), but the
 108  * estimate is acceptable if there's more than one extent being freed.
 109  * In the worst case of freeing every other block during a refcount decrease
 110  * operation, we amortize the space used for one EFI log item across 16
 111  * extents.
 112  */
 113 #define XFS_REFCOUNT_ITEM_OVERHEAD      32
 114
 115 extern int xfs_refcount_has_records(struct xfs_btree_cur *cur,
 116                 enum xfs_refc_domain domain, xfs_agblock_t bno,
 117                 xfs_extlen_t len, enum xbtree_recpacking *outcome);
 118 union xfs_btree_rec;
 119 extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
 120                 struct xfs_refcount_irec *irec);
 121 xfs_failaddr_t xfs_refcount_check_irec(struct xfs_perag *pag,
 122                 const struct xfs_refcount_irec *irec);
 123 extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
 124                 struct xfs_refcount_irec *irec, int *stat);
 125
 126 extern struct kmem_cache        *xfs_refcount_intent_cache;
 127
 128 int __init xfs_refcount_intent_init_cache(void);
 129 void xfs_refcount_intent_destroy_cache(void);
 130
 131 typedef int (*xfs_refcount_query_range_fn)(
 132         struct xfs_btree_cur            *cur,
 133         const struct xfs_refcount_irec  *rec,
 134         void                            *priv);
 135
 136 int xfs_refcount_query_range(struct xfs_btree_cur *cur,
 137                 const struct xfs_refcount_irec *low_rec,
 138                 const struct xfs_refcount_irec *high_rec,
 139                 xfs_refcount_query_range_fn fn, void *priv);
 140
 141 #endif  /* __XFS_REFCOUNT_H__ */