linux/fs/xfs/xfs_buf_item.h
Dave Chinner 5f6bed76c0 xfs: Introduce an ordered buffer item
If we have a buffer that we have modified but we do not wish to
physically log in a transaction (e.g. we've logged a logical
change), we still need to ensure that transactional integrity is
maintained. Hence we must not move the tail of the log past the
transaction that the buffer is associated with before the buffer is
written to disk.

This means these special buffers still need to be included in the
transaction and added to the AIL just like a normal buffer, but we
do not want the modifications to the buffer written into the
transaction. IOWs, what we want is an "ordered buffer" that
maintains the same transactional life cycle as a physically logged
buffer, just without the transcribing of the modifications to the
log.

Hence we need to flag the buffer as an "ordered buffer" to avoid
including it in vector size calculations or formatting during the
transaction. Once the transaction is committed, the buffer appears
for all intents to be the same as a physically logged buffer as it
transitions through the log and AIL.

Relogging will also work just fine for such an ordered buffer - the
logical transaction will be replayed before the subsequent
modifications that relog the buffer, so everything will be
reconstructed correctly by recovery.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-27 13:33:11 -05:00

175 lines
5.5 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 (1<<0)
/*
* This flag indicates that the buffer should not be replayed
* during recovery because its blocks are being freed.
*/
#define XFS_BLF_CANCEL (1<<1)
/*
* This flag indicates that the buffer contains on disk
* user or group dquots and may require special recovery handling.
*/
#define XFS_BLF_UDQUOT_BUF (1<<2)
#define XFS_BLF_PDQUOT_BUF (1<<3)
#define XFS_BLF_GDQUOT_BUF (1<<4)
#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;
/*
* All buffers now need to tell recovery where the magic number
* is so that it can verify and calculate the CRCs on the buffer correctly
* once the changes have been replayed into the buffer.
*
* The type value is held in the upper 5 bits of the blf_flags field, which is
* an unsigned 16 bit field. Hence we need to shift it 11 bits up and down.
*/
#define XFS_BLFT_BITS 5
#define XFS_BLFT_SHIFT 11
#define XFS_BLFT_MASK (((1 << XFS_BLFT_BITS) - 1) << XFS_BLFT_SHIFT)
enum xfs_blft {
XFS_BLFT_UNKNOWN_BUF = 0,
XFS_BLFT_UDQUOT_BUF,
XFS_BLFT_PDQUOT_BUF,
XFS_BLFT_GDQUOT_BUF,
XFS_BLFT_BTREE_BUF,
XFS_BLFT_AGF_BUF,
XFS_BLFT_AGFL_BUF,
XFS_BLFT_AGI_BUF,
XFS_BLFT_DINO_BUF,
XFS_BLFT_SYMLINK_BUF,
XFS_BLFT_DIR_BLOCK_BUF,
XFS_BLFT_DIR_DATA_BUF,
XFS_BLFT_DIR_FREE_BUF,
XFS_BLFT_DIR_LEAF1_BUF,
XFS_BLFT_DIR_LEAFN_BUF,
XFS_BLFT_DA_NODE_BUF,
XFS_BLFT_ATTR_LEAF_BUF,
XFS_BLFT_ATTR_RMT_BUF,
XFS_BLFT_SB_BUF,
XFS_BLFT_MAX_BUF = (1 << XFS_BLFT_BITS),
};
static inline void
xfs_blft_to_flags(struct xfs_buf_log_format *blf, enum xfs_blft type)
{
ASSERT(type > XFS_BLFT_UNKNOWN_BUF && type < XFS_BLFT_MAX_BUF);
blf->blf_flags &= ~XFS_BLFT_MASK;
blf->blf_flags |= ((type << XFS_BLFT_SHIFT) & XFS_BLFT_MASK);
}
static inline __uint16_t
xfs_blft_from_flags(struct xfs_buf_log_format *blf)
{
return (blf->blf_flags & XFS_BLFT_MASK) >> XFS_BLFT_SHIFT;
}
/*
* 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_ORDERED 0x80
#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" }, \
{ XFS_BLI_ORDERED, "ORDERED" }
#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 */
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 *);
void xfs_trans_buf_set_type(struct xfs_trans *, struct xfs_buf *,
enum xfs_blft);
void xfs_trans_buf_copy_type(struct xfs_buf *dst_bp, struct xfs_buf *src_bp);
#endif /* __KERNEL__ */
#endif /* __XFS_BUF_ITEM_H__ */