fs/xfs/xfs_rmap_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_RMAP_ITEM_H__
  21 #define __XFS_RMAP_ITEM_H__
  22
  23 /*
  24  * There are (currently) three pairs of rmap btree redo item types: map, unmap,
  25  * and convert.  The common abbreviations for these are RUI (rmap update
  26  * intent) and RUD (rmap update done).  The redo item type is encoded in the
  27  * 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 transaction
  31  * that records the associated rmapbt updates.  Typically, the first
  32  * transaction will record a bmbt update, followed by some number of
  33  * transactions containing rmapbt updates, and finally transactions with any
  34  * bnobt/cntbt updates.
  35  *
  36  * Should the system crash after the commit of the first transaction but
  37  * before the commit of the final transaction in a series, log recovery will
  38  * use the redo information recorded by the intent items to replay the
  39  * (rmapbt/bnobt/cntbt) metadata updates in the non-first transaction.
  40  */
  41
  42 /* kernel only RUI/RUD definitions */
  43
  44 struct xfs_mount;
  45 struct kmem_zone;
  46
  47 /*
  48  * Max number of extents in fast allocation path.
  49  */
  50 #define XFS_RUI_MAX_FAST_EXTENTS        16
  51
  52 /*
  53  * Define RUI flag bits. Manipulated by set/clear/test_bit operators.
  54  */
  55 #define XFS_RUI_RECOVERED               1
  56
  57 /*
  58  * This is the "rmap update intent" log item.  It is used to log the fact that
  59  * some reverse mappings need to change.  It is used in conjunction with the
  60  * "rmap update done" log item described below.
  61  *
  62  * These log items follow the same rules as struct xfs_efi_log_item; see the
  63  * comments about that structure (in xfs_extfree_item.h) for more details.
  64  */
  65 struct xfs_rui_log_item {
  66         struct xfs_log_item             rui_item;
  67         atomic_t                        rui_refcount;
  68         atomic_t                        rui_next_extent;
  69         unsigned long                   rui_flags;      /* misc flags */
  70         struct xfs_rui_log_format       rui_format;
  71 };
  72
  73 static inline size_t
  74 xfs_rui_log_item_sizeof(
  75         unsigned int            nr)
  76 {
  77         return offsetof(struct xfs_rui_log_item, rui_format) +
  78                         xfs_rui_log_format_sizeof(nr);
  79 }
  80
  81 /*
  82  * This is the "rmap update done" log item.  It is used to log the fact that
  83  * some rmapbt updates mentioned in an earlier rui item have been performed.
  84  */
  85 struct xfs_rud_log_item {
  86         struct xfs_log_item             rud_item;
  87         struct xfs_rui_log_item         *rud_ruip;
  88         struct xfs_rud_log_format       rud_format;
  89 };
  90
  91 extern struct kmem_zone *xfs_rui_zone;
  92 extern struct kmem_zone *xfs_rud_zone;
  93
  94 struct xfs_rui_log_item *xfs_rui_init(struct xfs_mount *, uint);
  95 struct xfs_rud_log_item *xfs_rud_init(struct xfs_mount *,
  96                 struct xfs_rui_log_item *);
  97 int xfs_rui_copy_format(struct xfs_log_iovec *buf,
  98                 struct xfs_rui_log_format *dst_rui_fmt);
  99 void xfs_rui_item_free(struct xfs_rui_log_item *);
 100 void xfs_rui_release(struct xfs_rui_log_item *);
 101 int xfs_rui_recover(struct xfs_mount *mp, struct xfs_rui_log_item *ruip);
 102
 103 #endif  /* __XFS_RMAP_ITEM_H__ */