fs/xfs/xfs_refcount_item.h

   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
  41 struct xfs_mount;
  42 struct 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  */
  64 struct 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
  72 static inline size_t
  73 xfs_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  */
  85 struct 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
  91 extern struct kmem_zone *xfs_cui_zone;
  92 extern struct kmem_zone *xfs_cud_zone;
  93
  94 struct xfs_cui_log_item *xfs_cui_init(struct xfs_mount *, uint);
  95 struct xfs_cud_log_item *xfs_cud_init(struct xfs_mount *,
  96                 struct xfs_cui_log_item *);
  97 void xfs_cui_item_free(struct xfs_cui_log_item *);
  98 void xfs_cui_release(struct xfs_cui_log_item *);
  99 int xfs_cui_recover(struct xfs_mount *mp, struct xfs_cui_log_item *cuip);
 100
 101 #endif  /* __XFS_REFCOUNT_ITEM_H__ */