alistair23-linux/fs/xfs/xfs_buf_item.h
Dave Chinner 372cc85ec6 xfs: support discontiguous buffers in the xfs_buf_log_item
discontigous buffer in separate buffer format structures. This means log
recovery will recover all the changes on a per segment basis without
requiring any knowledge of the fact that it was logged from a
compound buffer.

To do this, we need to be able to determine what buffer segment any
given offset into the compound buffer sits over. This enables us to
translate the dirty bitmap in the number of separate buffer format
structures required.

We also need to be able to determine the number of bitmap elements
that a given buffer segment has, as this determines the size of the
buffer format structure. Hence we need to be able to determine the
both the start offset into the buffer and the length of a given
segment to be able to calculate this.

With this information, we can preallocate, build and format the
correct log vector array for each segment in a compound buffer to
appear exactly the same as individually logged buffers in the log.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-01 14:50:06 -05:00

133 lines
4.2 KiB
C

/*
* Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_BUF_ITEM_H__
#define __XFS_BUF_ITEM_H__
extern kmem_zone_t *xfs_buf_item_zone;
/*
* This flag indicates that the buffer contains on disk inodes
* and requires special recovery handling.
*/
#define XFS_BLF_INODE_BUF 0x1
/*
* This flag indicates that the buffer should not be replayed
* during recovery because its blocks are being freed.
*/
#define XFS_BLF_CANCEL 0x2
/*
* This flag indicates that the buffer contains on disk
* user or group dquots and may require special recovery handling.
*/
#define XFS_BLF_UDQUOT_BUF 0x4
#define XFS_BLF_PDQUOT_BUF 0x8
#define XFS_BLF_GDQUOT_BUF 0x10
#define XFS_BLF_CHUNK 128
#define XFS_BLF_SHIFT 7
#define BIT_TO_WORD_SHIFT 5
#define NBWORD (NBBY * sizeof(unsigned int))
/*
* This is the structure used to lay out a buf log item in the
* log. The data map describes which 128 byte chunks of the buffer
* have been logged.
*/
#define XFS_BLF_DATAMAP_SIZE ((XFS_MAX_BLOCKSIZE / XFS_BLF_CHUNK) / NBWORD)
typedef struct xfs_buf_log_format {
unsigned short blf_type; /* buf log item type indicator */
unsigned short blf_size; /* size of this item */
ushort blf_flags; /* misc state */
ushort blf_len; /* number of blocks in this buf */
__int64_t blf_blkno; /* starting blkno of this buf */
unsigned int blf_map_size; /* used size of data bitmap in words */
unsigned int blf_data_map[XFS_BLF_DATAMAP_SIZE]; /* dirty bitmap */
} xfs_buf_log_format_t;
/*
* buf log item flags
*/
#define XFS_BLI_HOLD 0x01
#define XFS_BLI_DIRTY 0x02
#define XFS_BLI_STALE 0x04
#define XFS_BLI_LOGGED 0x08
#define XFS_BLI_INODE_ALLOC_BUF 0x10
#define XFS_BLI_STALE_INODE 0x20
#define XFS_BLI_INODE_BUF 0x40
#define XFS_BLI_FLAGS \
{ XFS_BLI_HOLD, "HOLD" }, \
{ XFS_BLI_DIRTY, "DIRTY" }, \
{ XFS_BLI_STALE, "STALE" }, \
{ XFS_BLI_LOGGED, "LOGGED" }, \
{ XFS_BLI_INODE_ALLOC_BUF, "INODE_ALLOC" }, \
{ XFS_BLI_STALE_INODE, "STALE_INODE" }, \
{ XFS_BLI_INODE_BUF, "INODE_BUF" }
#ifdef __KERNEL__
struct xfs_buf;
struct xfs_mount;
struct xfs_buf_log_item;
/*
* This is the in core log item structure used to track information
* needed to log buffers. It tracks how many times the lock has been
* locked, and which 128 byte chunks of the buffer are dirty.
*/
typedef struct xfs_buf_log_item {
xfs_log_item_t bli_item; /* common item structure */
struct xfs_buf *bli_buf; /* real buffer pointer */
unsigned int bli_flags; /* misc flags */
unsigned int bli_recur; /* lock recursion count */
atomic_t bli_refcount; /* cnt of tp refs */
#ifdef XFS_TRANS_DEBUG
char *bli_orig; /* original buffer copy */
char *bli_logged; /* bytes logged (bitmap) */
#endif
int bli_format_count; /* count of headers */
struct xfs_buf_log_format *bli_formats; /* array of in-log header ptrs */
struct xfs_buf_log_format bli_format; /* embedded in-log header */
} xfs_buf_log_item_t;
void xfs_buf_item_init(struct xfs_buf *, struct xfs_mount *);
void xfs_buf_item_relse(struct xfs_buf *);
void xfs_buf_item_log(xfs_buf_log_item_t *, uint, uint);
uint xfs_buf_item_dirty(xfs_buf_log_item_t *);
void xfs_buf_attach_iodone(struct xfs_buf *,
void(*)(struct xfs_buf *, xfs_log_item_t *),
xfs_log_item_t *);
void xfs_buf_iodone_callbacks(struct xfs_buf *);
void xfs_buf_iodone(struct xfs_buf *, struct xfs_log_item *);
#ifdef XFS_TRANS_DEBUG
void
xfs_buf_item_flush_log_debug(
struct xfs_buf *bp,
uint first,
uint last);
#else
#define xfs_buf_item_flush_log_debug(bp, first, last)
#endif
#endif /* __KERNEL__ */
#endif /* __XFS_BUF_ITEM_H__ */