/* * 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/dax.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_NO_IOACCT (1 << 3) /* bypass I/O accounting (non-LRU bufs) */ #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 */ #define _XBF_IN_FLIGHT (1 << 25) /* I/O in flight, for accounting purposes */ typedef unsigned int xfs_buf_flags_t; #define XFS_BUF_FLAGS \ { XBF_READ, "READ" }, \ { XBF_WRITE, "WRITE" }, \ { XBF_READ_AHEAD, "READ_AHEAD" }, \ { XBF_NO_IOACCT, "NO_IOACCT" }, \ { 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" }, \ { _XBF_IN_FLIGHT, "IN_FLIGHT" } /* * 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; struct percpu_counter bt_io_count; } 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 { char *name; 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 rhash_head b_rhash_head; /* pag buffer hash 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 */ /* * async write failure retry count. Initialised to zero on the first * failure, then when it exceeds the maximum configured without a * success the write is considered to be failed permanently and the * iodone handler will take appropriate action. * * For retry timeouts, we record the jiffie of the first failure. This * means that we can change the retry timeout for buffers already under * I/O and thus avoid getting stuck in a retry loop with a long timeout. * * last_error is used to ensure that we are getting repeated errors, not * different errors. e.g. a block device might change ENOSPC to EIO when * a failure timeout occurs, so we want to re-initialise the error * retry behaviour appropriately when that happens. */ int b_retries; unsigned long b_first_retry_time; /* in jiffies */ int b_last_error; 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 void *xfs_buf_offset(struct xfs_buf *, size_t); extern void xfs_buf_stale(struct xfs_buf *bp); /* 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); /* * 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__ */