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Diffstat (limited to 'fs/xfs/xfs_buf.h')
| -rw-r--r-- | fs/xfs/xfs_buf.h | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h new file mode 100644 index 000000000..75ff5d5a7 --- /dev/null +++ b/fs/xfs/xfs_buf.h @@ -0,0 +1,393 @@ +/* + * 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_BUF_H__ +#define __XFS_BUF_H__ + +#include <linux/list.h> +#include <linux/types.h> +#include <linux/spinlock.h> +#include <linux/mm.h> +#include <linux/fs.h> +#include <linux/buffer_head.h> +#include <linux/uio.h> +#include <linux/list_lru.h> + +/* + * Base types + */ + +#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL)) + +typedef enum { + XBRW_READ = 1, /* transfer into target memory */ + XBRW_WRITE = 2, /* transfer from target memory */ + XBRW_ZERO = 3, /* Zero target memory */ +} xfs_buf_rw_t; + +#define XBF_READ (1 << 0) /* buffer intended for reading from device */ +#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */ +#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */ +#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */ +#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */ +#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */ +#define XBF_WRITE_FAIL (1 << 24)/* async writes have failed on this buffer */ + +/* I/O hints for the BIO layer */ +#define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */ +#define XBF_FUA (1 << 11)/* force cache write through mode */ +#define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */ + +/* flags used only as arguments to access routines */ +#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */ +#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */ + +/* flags used only internally */ +#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */ +#define _XBF_KMEM (1 << 21)/* backed by heap memory */ +#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */ +#define _XBF_COMPOUND (1 << 23)/* compound buffer */ + +typedef unsigned int xfs_buf_flags_t; + +#define XFS_BUF_FLAGS \ + { XBF_READ, "READ" }, \ + { XBF_WRITE, "WRITE" }, \ + { XBF_READ_AHEAD, "READ_AHEAD" }, \ + { XBF_ASYNC, "ASYNC" }, \ + { XBF_DONE, "DONE" }, \ + { XBF_STALE, "STALE" }, \ + { XBF_WRITE_FAIL, "WRITE_FAIL" }, \ + { XBF_SYNCIO, "SYNCIO" }, \ + { XBF_FUA, "FUA" }, \ + { XBF_FLUSH, "FLUSH" }, \ + { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\ + { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\ + { _XBF_PAGES, "PAGES" }, \ + { _XBF_KMEM, "KMEM" }, \ + { _XBF_DELWRI_Q, "DELWRI_Q" }, \ + { _XBF_COMPOUND, "COMPOUND" } + + +/* + * Internal state flags. + */ +#define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */ + +/* + * The xfs_buftarg contains 2 notions of "sector size" - + * + * 1) The metadata sector size, which is the minimum unit and + * alignment of IO which will be performed by metadata operations. + * 2) The device logical sector size + * + * The first is specified at mkfs time, and is stored on-disk in the + * superblock's sb_sectsize. + * + * The latter is derived from the underlying device, and controls direct IO + * alignment constraints. + */ +typedef struct xfs_buftarg { + dev_t bt_dev; + struct block_device *bt_bdev; + struct backing_dev_info *bt_bdi; + struct xfs_mount *bt_mount; + unsigned int bt_meta_sectorsize; + size_t bt_meta_sectormask; + size_t bt_logical_sectorsize; + size_t bt_logical_sectormask; + + /* LRU control structures */ + struct shrinker bt_shrinker; + struct list_lru bt_lru; +} xfs_buftarg_t; + +struct xfs_buf; +typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); + + +#define XB_PAGES 2 + +struct xfs_buf_map { + xfs_daddr_t bm_bn; /* block number for I/O */ + int bm_len; /* size of I/O */ +}; + +#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \ + struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) }; + +struct xfs_buf_ops { + void (*verify_read)(struct xfs_buf *); + void (*verify_write)(struct xfs_buf *); +}; + +typedef struct xfs_buf { + /* + * first cacheline holds all the fields needed for an uncontended cache + * hit to be fully processed. The semaphore straddles the cacheline + * boundary, but the counter and lock sits on the first cacheline, + * which is the only bit that is touched if we hit the semaphore + * fast-path on locking. + */ + struct rb_node b_rbnode; /* rbtree node */ + xfs_daddr_t b_bn; /* block number of buffer */ + int b_length; /* size of buffer in BBs */ + atomic_t b_hold; /* reference count */ + atomic_t b_lru_ref; /* lru reclaim ref count */ + xfs_buf_flags_t b_flags; /* status flags */ + struct semaphore b_sema; /* semaphore for lockables */ + + /* + * concurrent access to b_lru and b_lru_flags are protected by + * bt_lru_lock and not by b_sema + */ + struct list_head b_lru; /* lru list */ + spinlock_t b_lock; /* internal state lock */ + unsigned int b_state; /* internal state flags */ + int b_io_error; /* internal IO error state */ + wait_queue_head_t b_waiters; /* unpin waiters */ + struct list_head b_list; + struct xfs_perag *b_pag; /* contains rbtree root */ + xfs_buftarg_t *b_target; /* buffer target (device) */ + void *b_addr; /* virtual address of buffer */ + struct work_struct b_ioend_work; + struct workqueue_struct *b_ioend_wq; /* I/O completion wq */ + xfs_buf_iodone_t b_iodone; /* I/O completion function */ + struct completion b_iowait; /* queue for I/O waiters */ + void *b_fspriv; + struct xfs_trans *b_transp; + struct page **b_pages; /* array of page pointers */ + struct page *b_page_array[XB_PAGES]; /* inline pages */ + struct xfs_buf_map *b_maps; /* compound buffer map */ + struct xfs_buf_map __b_map; /* inline compound buffer map */ + int b_map_count; + int b_io_length; /* IO size in BBs */ + atomic_t b_pin_count; /* pin count */ + atomic_t b_io_remaining; /* #outstanding I/O requests */ + unsigned int b_page_count; /* size of page array */ + unsigned int b_offset; /* page offset in first page */ + int b_error; /* error code on I/O */ + const struct xfs_buf_ops *b_ops; + +#ifdef XFS_BUF_LOCK_TRACKING + int b_last_holder; +#endif +} xfs_buf_t; + +/* Finding and Reading Buffers */ +struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, + struct xfs_buf_map *map, int nmaps, + xfs_buf_flags_t flags, struct xfs_buf *new_bp); + +static inline struct xfs_buf * +xfs_incore( + struct xfs_buftarg *target, + xfs_daddr_t blkno, + size_t numblks, + xfs_buf_flags_t flags) +{ + DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); + return _xfs_buf_find(target, &map, 1, flags, NULL); +} + +struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, + struct xfs_buf_map *map, int nmaps, + xfs_buf_flags_t flags); + +static inline struct xfs_buf * +xfs_buf_alloc( + struct xfs_buftarg *target, + xfs_daddr_t blkno, + size_t numblks, + xfs_buf_flags_t flags) +{ + DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); + return _xfs_buf_alloc(target, &map, 1, flags); +} + +struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, + struct xfs_buf_map *map, int nmaps, + xfs_buf_flags_t flags); +struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, + struct xfs_buf_map *map, int nmaps, + xfs_buf_flags_t flags, + const struct xfs_buf_ops *ops); +void xfs_buf_readahead_map(struct xfs_buftarg *target, + struct xfs_buf_map *map, int nmaps, + const struct xfs_buf_ops *ops); + +static inline struct xfs_buf * +xfs_buf_get( + struct xfs_buftarg *target, + xfs_daddr_t blkno, + size_t numblks, + xfs_buf_flags_t flags) +{ + DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); + return xfs_buf_get_map(target, &map, 1, flags); +} + +static inline struct xfs_buf * +xfs_buf_read( + struct xfs_buftarg *target, + xfs_daddr_t blkno, + size_t numblks, + xfs_buf_flags_t flags, + const struct xfs_buf_ops *ops) +{ + DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); + return xfs_buf_read_map(target, &map, 1, flags, ops); +} + +static inline void +xfs_buf_readahead( + struct xfs_buftarg *target, + xfs_daddr_t blkno, + size_t numblks, + const struct xfs_buf_ops *ops) +{ + DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); + return xfs_buf_readahead_map(target, &map, 1, ops); +} + +struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); +void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); +int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); + +struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, + int flags); +int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr, + size_t numblks, int flags, struct xfs_buf **bpp, + const struct xfs_buf_ops *ops); +void xfs_buf_hold(struct xfs_buf *bp); + +/* Releasing Buffers */ +extern void xfs_buf_free(xfs_buf_t *); +extern void xfs_buf_rele(xfs_buf_t *); + +/* Locking and Unlocking Buffers */ +extern int xfs_buf_trylock(xfs_buf_t *); +extern void xfs_buf_lock(xfs_buf_t *); +extern void xfs_buf_unlock(xfs_buf_t *); +#define xfs_buf_islocked(bp) \ + ((bp)->b_sema.count <= 0) + +/* Buffer Read and Write Routines */ +extern int xfs_bwrite(struct xfs_buf *bp); +extern void xfs_buf_ioend(struct xfs_buf *bp); +extern void xfs_buf_ioerror(xfs_buf_t *, int); +extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); +extern void xfs_buf_submit(struct xfs_buf *bp); +extern int xfs_buf_submit_wait(struct xfs_buf *bp); +extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, + xfs_buf_rw_t); +#define xfs_buf_zero(bp, off, len) \ + xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) + +/* Buffer Utility Routines */ +extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t); + +/* Delayed Write Buffer Routines */ +extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); +extern int xfs_buf_delwri_submit(struct list_head *); +extern int xfs_buf_delwri_submit_nowait(struct list_head *); + +/* Buffer Daemon Setup Routines */ +extern int xfs_buf_init(void); +extern void xfs_buf_terminate(void); + +#define XFS_BUF_ZEROFLAGS(bp) \ + ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \ + XBF_SYNCIO|XBF_FUA|XBF_FLUSH| \ + XBF_WRITE_FAIL)) + +void xfs_buf_stale(struct xfs_buf *bp); +#define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) +#define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) + +#define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) +#define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) +#define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) + +#define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) +#define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) +#define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) + +#define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) +#define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) +#define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) + +#define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) +#define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) +#define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) + +/* + * These macros use the IO block map rather than b_bn. b_bn is now really + * just for the buffer cache index for cached buffers. As IO does not use b_bn + * anymore, uncached buffers do not use b_bn at all and hence must modify the IO + * map directly. Uncached buffers are not allowed to be discontiguous, so this + * is safe to do. + * + * In future, uncached buffers will pass the block number directly to the io + * request function and hence these macros will go away at that point. + */ +#define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) +#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno)) + +static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) +{ + atomic_set(&bp->b_lru_ref, lru_ref); +} + +static inline int xfs_buf_ispinned(struct xfs_buf *bp) +{ + return atomic_read(&bp->b_pin_count); +} + +static inline void xfs_buf_relse(xfs_buf_t *bp) +{ + xfs_buf_unlock(bp); + xfs_buf_rele(bp); +} + +static inline int +xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset) +{ + return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), + cksum_offset); +} + +static inline void +xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset) +{ + xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), + cksum_offset); +} + +/* + * Handling of buftargs. + */ +extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, + struct block_device *); +extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); +extern void xfs_wait_buftarg(xfs_buftarg_t *); +extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); + +#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) +#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) + +#endif /* __XFS_BUF_H__ */ |