LXR linux/fs/xfs/xfs_refcount

   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_ITEM_H__
  21#define __XFS_REFCOUNT_ITEM_H__
  22
  23/*
  24 * There are (currently) two pairs of refcount btree redo item types:
  25 * increase and decrease.  The log items for these are CUI (refcount
  26 * update intent) and CUD (refcount update done).  The redo item type
  27 * is encoded in the flags field of each xfs_map_extent.
  28 *
  29 * *I items should be recorded in the *first* of a series of rolled
  30 * transactions, and the *D items should be recorded in the same
  31 * transaction that records the associated refcountbt updates.
  32 *
  33 * Should the system crash after the commit of the first transaction
  34 * but before the commit of the final transaction in a series, log
  35 * recovery will use the redo information recorded by the intent items
  36 * to replay the refcountbt metadata updates.
  37 */
  38
  39/* kernel only CUI/CUD definitions */
  40
  41struct xfs_mount;
  42struct kmem_zone;
  43
  44/*
  45 * Max number of extents in fast allocation path.
  46 */
  47#define XFS_CUI_MAX_FAST_EXTENTS        16
  48
  49/*
  50 * Define CUI flag bits. Manipulated by set/clear/test_bit operators.
  51 */
  52#define XFS_CUI_RECOVERED               1
  53
  54/*
  55 * This is the "refcount update intent" log item.  It is used to log
  56 * the fact that some reverse mappings need to change.  It is used in
  57 * conjunction with the "refcount update done" log item described
  58 * below.
  59 *
  60 * These log items follow the same rules as struct xfs_efi_log_item;
  61 * see the comments about that structure (in xfs_extfree_item.h) for
  62 * more details.
  63 */
  64struct xfs_cui_log_item {
  65        struct xfs_log_item             cui_item;
  66        atomic_t                        cui_refcount;
  67        atomic_t                        cui_next_extent;
  68        unsigned long                   cui_flags;      /* misc flags */
  69        struct xfs_cui_log_format       cui_format;
  70};
  71
  72static inline size_t
  73xfs_cui_log_item_sizeof(
  74        unsigned int            nr)
  75{
  76        return offsetof(struct xfs_cui_log_item, cui_format) +
  77                        xfs_cui_log_format_sizeof(nr);
  78}
  79
  80/*
  81 * This is the "refcount update done" log item.  It is used to log the
  82 * fact that some refcountbt updates mentioned in an earlier cui item
  83 * have been performed.
  84 */
  85struct xfs_cud_log_item {
  86        struct xfs_log_item             cud_item;
  87        struct xfs_cui_log_item         *cud_cuip;
  88        struct xfs_cud_log_format       cud_format;
  89};
  90
  91extern struct kmem_zone *xfs_cui_zone;
  92extern struct kmem_zone *xfs_cud_zone;
  93
  94struct xfs_cui_log_item *xfs_cui_init(struct xfs_mount *, uint);
  95struct xfs_cud_log_item *xfs_cud_init(struct xfs_mount *,
  96                struct xfs_cui_log_item *);
  97void xfs_cui_item_free(struct xfs_cui_log_item *);
  98void xfs_cui_release(struct xfs_cui_log_item *);
  99int xfs_cui_recover(struct xfs_mount *mp, struct xfs_cui_log_item *cuip);
 100
 101#endif  /* __XFS_REFCOUNT_ITEM_H__ */
 102