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linux-next/fs/xfs/xfs_alloc_btree.h
Dave Chinner 77c1a08fc9 xfs: struct xfs_buf_log_format isn't variable sized.
The struct xfs_buf_log_format wants to think the dirty bitmap is
variable sized.  In fact, it is variable size on disk simply due to
the way we map it from the in-memory structure, but we still just
use a fixed size memory allocation for the in-memory structure.

Hence it makes no sense to set the function up as a variable sized
structure when we already know it's maximum size, and we always
allocate it as such. Simplify the structure by making the dirty
bitmap a fixed sized array and just using the size of the structure
for the allocation size.

This will make it much simpler to allocate and manipulate an array
of format structures for discontiguous buffer support.

The previous struct xfs_buf_log_item size according to
/proc/slabinfo was 224 bytes. pahole doesn't give the same size
because of the variable size definition. With this modification,
pahole reports the same as /proc/slabinfo:

	/* size: 224, cachelines: 4, members: 6 */

Because the xfs_buf_log_item size is now determined by the maximum
supported block size we introduce a dependency on xfs_alloc_btree.h.
Avoid this dependency by moving the idefines for the maximum block
sizes supported to xfs_types.h with all the other max/min type
defines to avoid any new dependencies.

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 14:50:04 -05:00

97 lines
2.9 KiB
C

/*
* Copyright (c) 2000,2005 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_ALLOC_BTREE_H__
#define __XFS_ALLOC_BTREE_H__
/*
* Freespace on-disk structures
*/
struct xfs_buf;
struct xfs_btree_cur;
struct xfs_mount;
/*
* There are two on-disk btrees, one sorted by blockno and one sorted
* by blockcount and blockno. All blocks look the same to make the code
* simpler; if we have time later, we'll make the optimizations.
*/
#define XFS_ABTB_MAGIC 0x41425442 /* 'ABTB' for bno tree */
#define XFS_ABTC_MAGIC 0x41425443 /* 'ABTC' for cnt tree */
/*
* Data record/key structure
*/
typedef struct xfs_alloc_rec {
__be32 ar_startblock; /* starting block number */
__be32 ar_blockcount; /* count of free blocks */
} xfs_alloc_rec_t, xfs_alloc_key_t;
typedef struct xfs_alloc_rec_incore {
xfs_agblock_t ar_startblock; /* starting block number */
xfs_extlen_t ar_blockcount; /* count of free blocks */
} xfs_alloc_rec_incore_t;
/* btree pointer type */
typedef __be32 xfs_alloc_ptr_t;
/*
* Block numbers in the AG:
* SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
*/
#define XFS_BNO_BLOCK(mp) ((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
#define XFS_CNT_BLOCK(mp) ((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
/*
* Btree block header size depends on a superblock flag.
*
* (not quite yet, but soon)
*/
#define XFS_ALLOC_BLOCK_LEN(mp) XFS_BTREE_SBLOCK_LEN
/*
* Record, key, and pointer address macros for btree blocks.
*
* (note that some of these may appear unused, but they are used in userspace)
*/
#define XFS_ALLOC_REC_ADDR(mp, block, index) \
((xfs_alloc_rec_t *) \
((char *)(block) + \
XFS_ALLOC_BLOCK_LEN(mp) + \
(((index) - 1) * sizeof(xfs_alloc_rec_t))))
#define XFS_ALLOC_KEY_ADDR(mp, block, index) \
((xfs_alloc_key_t *) \
((char *)(block) + \
XFS_ALLOC_BLOCK_LEN(mp) + \
((index) - 1) * sizeof(xfs_alloc_key_t)))
#define XFS_ALLOC_PTR_ADDR(mp, block, index, maxrecs) \
((xfs_alloc_ptr_t *) \
((char *)(block) + \
XFS_ALLOC_BLOCK_LEN(mp) + \
(maxrecs) * sizeof(xfs_alloc_key_t) + \
((index) - 1) * sizeof(xfs_alloc_ptr_t)))
extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
struct xfs_trans *, struct xfs_buf *,
xfs_agnumber_t, xfs_btnum_t);
extern int xfs_allocbt_maxrecs(struct xfs_mount *, int, int);
#endif /* __XFS_ALLOC_BTREE_H__ */