365 lines
12 KiB
C
365 lines
12 KiB
C
/*
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* Copyright (c) 2000-2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __XFS_BUF_H__
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#define __XFS_BUF_H__
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#include <linux/list.h>
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/uio.h>
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/*
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* Base types
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*/
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#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
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typedef enum {
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XBRW_READ = 1, /* transfer into target memory */
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XBRW_WRITE = 2, /* transfer from target memory */
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XBRW_ZERO = 3, /* Zero target memory */
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} xfs_buf_rw_t;
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#define XBF_READ (1 << 0) /* buffer intended for reading from device */
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#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
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#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
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#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
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#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
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#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
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/* I/O hints for the BIO layer */
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#define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
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#define XBF_FUA (1 << 11)/* force cache write through mode */
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#define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
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/* flags used only as arguments to access routines */
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#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
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#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
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/* flags used only internally */
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#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
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#define _XBF_KMEM (1 << 21)/* backed by heap memory */
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#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
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#define _XBF_COMPOUND (1 << 23)/* compound buffer */
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#define _XBF_LRU_DISPOSE (1 << 24)/* buffer being discarded */
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typedef unsigned int xfs_buf_flags_t;
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#define XFS_BUF_FLAGS \
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{ XBF_READ, "READ" }, \
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{ XBF_WRITE, "WRITE" }, \
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{ XBF_READ_AHEAD, "READ_AHEAD" }, \
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{ XBF_ASYNC, "ASYNC" }, \
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{ XBF_DONE, "DONE" }, \
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{ XBF_STALE, "STALE" }, \
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{ XBF_SYNCIO, "SYNCIO" }, \
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{ XBF_FUA, "FUA" }, \
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{ XBF_FLUSH, "FLUSH" }, \
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{ XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
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{ XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
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{ _XBF_PAGES, "PAGES" }, \
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{ _XBF_KMEM, "KMEM" }, \
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{ _XBF_DELWRI_Q, "DELWRI_Q" }, \
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{ _XBF_COMPOUND, "COMPOUND" }, \
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{ _XBF_LRU_DISPOSE, "LRU_DISPOSE" }
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typedef struct xfs_buftarg {
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dev_t bt_dev;
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struct block_device *bt_bdev;
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struct backing_dev_info *bt_bdi;
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struct xfs_mount *bt_mount;
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unsigned int bt_bsize;
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unsigned int bt_sshift;
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size_t bt_smask;
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/* LRU control structures */
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struct shrinker bt_shrinker;
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struct list_head bt_lru;
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spinlock_t bt_lru_lock;
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unsigned int bt_lru_nr;
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} xfs_buftarg_t;
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struct xfs_buf;
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typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
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#define XB_PAGES 2
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struct xfs_buf_map {
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xfs_daddr_t bm_bn; /* block number for I/O */
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int bm_len; /* size of I/O */
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};
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#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
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struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
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struct xfs_buf_ops {
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void (*verify_read)(struct xfs_buf *);
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void (*verify_write)(struct xfs_buf *);
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};
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typedef struct xfs_buf {
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/*
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* first cacheline holds all the fields needed for an uncontended cache
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* hit to be fully processed. The semaphore straddles the cacheline
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* boundary, but the counter and lock sits on the first cacheline,
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* which is the only bit that is touched if we hit the semaphore
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* fast-path on locking.
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*/
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struct rb_node b_rbnode; /* rbtree node */
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xfs_daddr_t b_bn; /* block number of buffer */
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int b_length; /* size of buffer in BBs */
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atomic_t b_hold; /* reference count */
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atomic_t b_lru_ref; /* lru reclaim ref count */
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xfs_buf_flags_t b_flags; /* status flags */
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struct semaphore b_sema; /* semaphore for lockables */
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/*
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* concurrent access to b_lru and b_lru_flags are protected by
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* bt_lru_lock and not by b_sema
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*/
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struct list_head b_lru; /* lru list */
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xfs_buf_flags_t b_lru_flags; /* internal lru status flags */
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wait_queue_head_t b_waiters; /* unpin waiters */
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struct list_head b_list;
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struct xfs_perag *b_pag; /* contains rbtree root */
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xfs_buftarg_t *b_target; /* buffer target (device) */
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void *b_addr; /* virtual address of buffer */
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struct work_struct b_iodone_work;
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xfs_buf_iodone_t b_iodone; /* I/O completion function */
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struct completion b_iowait; /* queue for I/O waiters */
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void *b_fspriv;
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struct xfs_trans *b_transp;
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struct page **b_pages; /* array of page pointers */
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struct page *b_page_array[XB_PAGES]; /* inline pages */
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struct xfs_buf_map *b_maps; /* compound buffer map */
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struct xfs_buf_map __b_map; /* inline compound buffer map */
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int b_map_count;
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int b_io_length; /* IO size in BBs */
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atomic_t b_pin_count; /* pin count */
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atomic_t b_io_remaining; /* #outstanding I/O requests */
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unsigned int b_page_count; /* size of page array */
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unsigned int b_offset; /* page offset in first page */
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unsigned short b_error; /* error code on I/O */
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const struct xfs_buf_ops *b_ops;
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#ifdef XFS_BUF_LOCK_TRACKING
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int b_last_holder;
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#endif
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} xfs_buf_t;
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/* Finding and Reading Buffers */
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struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags, struct xfs_buf *new_bp);
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static inline struct xfs_buf *
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xfs_incore(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return _xfs_buf_find(target, &map, 1, flags, NULL);
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}
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struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags);
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static inline struct xfs_buf *
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xfs_buf_alloc(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return _xfs_buf_alloc(target, &map, 1, flags);
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}
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struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags);
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struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags,
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const struct xfs_buf_ops *ops);
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void xfs_buf_readahead_map(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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const struct xfs_buf_ops *ops);
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static inline struct xfs_buf *
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xfs_buf_get(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return xfs_buf_get_map(target, &map, 1, flags);
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}
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static inline struct xfs_buf *
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xfs_buf_read(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags,
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const struct xfs_buf_ops *ops)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return xfs_buf_read_map(target, &map, 1, flags, ops);
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}
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static inline void
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xfs_buf_readahead(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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const struct xfs_buf_ops *ops)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return xfs_buf_readahead_map(target, &map, 1, ops);
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}
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struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
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void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
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int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
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struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
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int flags);
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struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
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xfs_daddr_t daddr, size_t numblks, int flags,
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const struct xfs_buf_ops *ops);
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void xfs_buf_hold(struct xfs_buf *bp);
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/* Releasing Buffers */
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extern void xfs_buf_free(xfs_buf_t *);
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extern void xfs_buf_rele(xfs_buf_t *);
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/* Locking and Unlocking Buffers */
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extern int xfs_buf_trylock(xfs_buf_t *);
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extern void xfs_buf_lock(xfs_buf_t *);
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extern void xfs_buf_unlock(xfs_buf_t *);
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#define xfs_buf_islocked(bp) \
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((bp)->b_sema.count <= 0)
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/* Buffer Read and Write Routines */
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extern int xfs_bwrite(struct xfs_buf *bp);
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extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
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extern void xfs_buf_ioend(xfs_buf_t *, int);
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extern void xfs_buf_ioerror(xfs_buf_t *, int);
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extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
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extern void xfs_buf_iorequest(xfs_buf_t *);
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extern int xfs_buf_iowait(xfs_buf_t *);
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extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
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xfs_buf_rw_t);
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#define xfs_buf_zero(bp, off, len) \
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xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
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static inline int xfs_buf_geterror(xfs_buf_t *bp)
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{
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return bp ? bp->b_error : ENOMEM;
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}
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/* Buffer Utility Routines */
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extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
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/* Delayed Write Buffer Routines */
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extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
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extern int xfs_buf_delwri_submit(struct list_head *);
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extern int xfs_buf_delwri_submit_nowait(struct list_head *);
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/* Buffer Daemon Setup Routines */
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extern int xfs_buf_init(void);
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extern void xfs_buf_terminate(void);
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#define XFS_BUF_ZEROFLAGS(bp) \
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((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
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XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
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void xfs_buf_stale(struct xfs_buf *bp);
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#define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
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#define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
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#define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
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#define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
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#define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
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#define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
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#define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
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#define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
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#define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
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#define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
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#define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
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#define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
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#define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
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#define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
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/*
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* These macros use the IO block map rather than b_bn. b_bn is now really
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* just for the buffer cache index for cached buffers. As IO does not use b_bn
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* anymore, uncached buffers do not use b_bn at all and hence must modify the IO
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* map directly. Uncached buffers are not allowed to be discontiguous, so this
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* is safe to do.
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*
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* In future, uncached buffers will pass the block number directly to the io
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* request function and hence these macros will go away at that point.
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*/
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#define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn)
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#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
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static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
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{
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atomic_set(&bp->b_lru_ref, lru_ref);
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}
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static inline int xfs_buf_ispinned(struct xfs_buf *bp)
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{
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return atomic_read(&bp->b_pin_count);
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}
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static inline void xfs_buf_relse(xfs_buf_t *bp)
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{
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xfs_buf_unlock(bp);
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xfs_buf_rele(bp);
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}
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/*
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* Handling of buftargs.
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*/
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extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
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struct block_device *, int, const char *);
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extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
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extern void xfs_wait_buftarg(xfs_buftarg_t *);
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extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
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#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
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#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
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#endif /* __XFS_BUF_H__ */
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