LXR linux/fs/xfs/libxfs/xfs

   1/*
   2 * Copyright (C) 2016 Oracle.  All Rights Reserved.
   3 *
   4 * Author: Darrick J. Wong <darrick.wong@oracle.com>
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version 2
   9 * of the License, or (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it would be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write the Free Software Foundation,
  18 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
  19 */
  20#ifndef __XFS_REFCOUNT_H__
  21#define __XFS_REFCOUNT_H__
  22
  23extern int xfs_refcount_lookup_le(struct xfs_btree_cur *cur,
  24                xfs_agblock_t bno, int *stat);
  25extern int xfs_refcount_lookup_ge(struct xfs_btree_cur *cur,
  26                xfs_agblock_t bno, int *stat);
  27extern int xfs_refcount_get_rec(struct xfs_btree_cur *cur,
  28                struct xfs_refcount_irec *irec, int *stat);
  29
  30enum xfs_refcount_intent_type {
  31        XFS_REFCOUNT_INCREASE = 1,
  32        XFS_REFCOUNT_DECREASE,
  33        XFS_REFCOUNT_ALLOC_COW,
  34        XFS_REFCOUNT_FREE_COW,
  35};
  36
  37struct xfs_refcount_intent {
  38        struct list_head                        ri_list;
  39        enum xfs_refcount_intent_type           ri_type;
  40        xfs_fsblock_t                           ri_startblock;
  41        xfs_extlen_t                            ri_blockcount;
  42};
  43
  44extern int xfs_refcount_increase_extent(struct xfs_mount *mp,
  45                struct xfs_defer_ops *dfops, struct xfs_bmbt_irec *irec);
  46extern int xfs_refcount_decrease_extent(struct xfs_mount *mp,
  47                struct xfs_defer_ops *dfops, struct xfs_bmbt_irec *irec);
  48
  49extern void xfs_refcount_finish_one_cleanup(struct xfs_trans *tp,
  50                struct xfs_btree_cur *rcur, int error);
  51extern int xfs_refcount_finish_one(struct xfs_trans *tp,
  52                struct xfs_defer_ops *dfops, enum xfs_refcount_intent_type type,
  53                xfs_fsblock_t startblock, xfs_extlen_t blockcount,
  54                xfs_fsblock_t *new_fsb, xfs_extlen_t *new_len,
  55                struct xfs_btree_cur **pcur);
  56
  57extern int xfs_refcount_find_shared(struct xfs_btree_cur *cur,
  58                xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
  59                xfs_extlen_t *flen, bool find_end_of_shared);
  60
  61extern int xfs_refcount_alloc_cow_extent(struct xfs_mount *mp,
  62                struct xfs_defer_ops *dfops, xfs_fsblock_t fsb,
  63                xfs_extlen_t len);
  64extern int xfs_refcount_free_cow_extent(struct xfs_mount *mp,
  65                struct xfs_defer_ops *dfops, xfs_fsblock_t fsb,
  66                xfs_extlen_t len);
  67extern int xfs_refcount_recover_cow_leftovers(struct xfs_mount *mp,
  68                xfs_agnumber_t agno);
  69
  70/*
  71 * While we're adjusting the refcounts records of an extent, we have
  72 * to keep an eye on the number of extents we're dirtying -- run too
  73 * many in a single transaction and we'll exceed the transaction's
  74 * reservation and crash the fs.  Each record adds 12 bytes to the
  75 * log (plus any key updates) so we'll conservatively assume 32 bytes
  76 * per record.  We must also leave space for btree splits on both ends
  77 * of the range and space for the CUD and a new CUI.
  78 */
  79#define XFS_REFCOUNT_ITEM_OVERHEAD      32
  80
  81static inline xfs_fileoff_t xfs_refcount_max_unmap(int log_res)
  82{
  83        return (log_res * 3 / 4) / XFS_REFCOUNT_ITEM_OVERHEAD;
  84}
  85
  86extern int xfs_refcount_has_record(struct xfs_btree_cur *cur,
  87                xfs_agblock_t bno, xfs_extlen_t len, bool *exists);
  88
  89#endif  /* __XFS_REFCOUNT_H__ */
  90