1 /* 2 * Copyright (c) 2000-2005 Silicon Graphics, Inc. 3 * All Rights Reserved. 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 #ifndef __XFS_BUF_H__ 19 #define __XFS_BUF_H__ 20 21 #include <linux/list.h> 22 #include <linux/types.h> 23 #include <linux/spinlock.h> 24 #include <linux/mm.h> 25 #include <linux/fs.h> 26 #include <linux/buffer_head.h> 27 #include <linux/uio.h> 28 29 /* 30 * Base types 31 */ 32 33 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL)) 34 35 typedef enum { 36 XBRW_READ = 1, /* transfer into target memory */ 37 XBRW_WRITE = 2, /* transfer from target memory */ 38 XBRW_ZERO = 3, /* Zero target memory */ 39 } xfs_buf_rw_t; 40 41 #define XBF_READ (1 << 0) /* buffer intended for reading from device */ 42 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */ 43 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */ 44 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */ 45 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */ 46 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */ 47 48 /* I/O hints for the BIO layer */ 49 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */ 50 #define XBF_FUA (1 << 11)/* force cache write through mode */ 51 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */ 52 53 /* flags used only as arguments to access routines */ 54 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */ 55 #define XBF_UNMAPPED (1 << 17)/* do not map the buffer */ 56 57 /* flags used only internally */ 58 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */ 59 #define _XBF_KMEM (1 << 21)/* backed by heap memory */ 60 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */ 61 62 typedef unsigned int xfs_buf_flags_t; 63 64 #define XFS_BUF_FLAGS \ 65 { XBF_READ, "READ" }, \ 66 { XBF_WRITE, "WRITE" }, \ 67 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 68 { XBF_ASYNC, "ASYNC" }, \ 69 { XBF_DONE, "DONE" }, \ 70 { XBF_STALE, "STALE" }, \ 71 { XBF_SYNCIO, "SYNCIO" }, \ 72 { XBF_FUA, "FUA" }, \ 73 { XBF_FLUSH, "FLUSH" }, \ 74 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\ 75 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\ 76 { _XBF_PAGES, "PAGES" }, \ 77 { _XBF_KMEM, "KMEM" }, \ 78 { _XBF_DELWRI_Q, "DELWRI_Q" } 79 80 typedef struct xfs_buftarg { 81 dev_t bt_dev; 82 struct block_device *bt_bdev; 83 struct backing_dev_info *bt_bdi; 84 struct xfs_mount *bt_mount; 85 unsigned int bt_bsize; 86 unsigned int bt_sshift; 87 size_t bt_smask; 88 89 /* LRU control structures */ 90 struct shrinker bt_shrinker; 91 struct list_head bt_lru; 92 spinlock_t bt_lru_lock; 93 unsigned int bt_lru_nr; 94 } xfs_buftarg_t; 95 96 struct xfs_buf; 97 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 98 99 #define XB_PAGES 2 100 101 typedef struct xfs_buf { 102 /* 103 * first cacheline holds all the fields needed for an uncontended cache 104 * hit to be fully processed. The semaphore straddles the cacheline 105 * boundary, but the counter and lock sits on the first cacheline, 106 * which is the only bit that is touched if we hit the semaphore 107 * fast-path on locking. 108 */ 109 struct rb_node b_rbnode; /* rbtree node */ 110 xfs_daddr_t b_bn; /* block number for I/O */ 111 int b_length; /* size of buffer in BBs */ 112 atomic_t b_hold; /* reference count */ 113 atomic_t b_lru_ref; /* lru reclaim ref count */ 114 xfs_buf_flags_t b_flags; /* status flags */ 115 struct semaphore b_sema; /* semaphore for lockables */ 116 117 struct list_head b_lru; /* lru list */ 118 wait_queue_head_t b_waiters; /* unpin waiters */ 119 struct list_head b_list; 120 struct xfs_perag *b_pag; /* contains rbtree root */ 121 xfs_buftarg_t *b_target; /* buffer target (device) */ 122 void *b_addr; /* virtual address of buffer */ 123 struct work_struct b_iodone_work; 124 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 125 struct completion b_iowait; /* queue for I/O waiters */ 126 void *b_fspriv; 127 struct xfs_trans *b_transp; 128 struct page **b_pages; /* array of page pointers */ 129 struct page *b_page_array[XB_PAGES]; /* inline pages */ 130 int b_io_length; /* IO size in BBs */ 131 atomic_t b_pin_count; /* pin count */ 132 atomic_t b_io_remaining; /* #outstanding I/O requests */ 133 unsigned int b_page_count; /* size of page array */ 134 unsigned int b_offset; /* page offset in first page */ 135 unsigned short b_error; /* error code on I/O */ 136 #ifdef XFS_BUF_LOCK_TRACKING 137 int b_last_holder; 138 #endif 139 } xfs_buf_t; 140 141 142 /* Finding and Reading Buffers */ 143 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, xfs_daddr_t blkno, 144 size_t numblks, xfs_buf_flags_t flags, 145 struct xfs_buf *new_bp); 146 #define xfs_incore(buftarg,blkno,len,lockit) \ 147 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL) 148 149 struct xfs_buf *xfs_buf_get(struct xfs_buftarg *target, xfs_daddr_t blkno, 150 size_t numblks, xfs_buf_flags_t flags); 151 struct xfs_buf *xfs_buf_read(struct xfs_buftarg *target, xfs_daddr_t blkno, 152 size_t numblks, xfs_buf_flags_t flags); 153 void xfs_buf_readahead(struct xfs_buftarg *target, xfs_daddr_t blkno, 154 size_t numblks); 155 156 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); 157 struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *target, xfs_daddr_t blkno, 158 size_t numblks, xfs_buf_flags_t flags); 159 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 160 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 161 162 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 163 int flags); 164 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target, 165 xfs_daddr_t daddr, size_t numblks, int flags); 166 void xfs_buf_hold(struct xfs_buf *bp); 167 168 /* Releasing Buffers */ 169 extern void xfs_buf_free(xfs_buf_t *); 170 extern void xfs_buf_rele(xfs_buf_t *); 171 172 /* Locking and Unlocking Buffers */ 173 extern int xfs_buf_trylock(xfs_buf_t *); 174 extern void xfs_buf_lock(xfs_buf_t *); 175 extern void xfs_buf_unlock(xfs_buf_t *); 176 #define xfs_buf_islocked(bp) \ 177 ((bp)->b_sema.count <= 0) 178 179 /* Buffer Read and Write Routines */ 180 extern int xfs_bwrite(struct xfs_buf *bp); 181 182 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *); 183 extern int xfs_bdstrat_cb(struct xfs_buf *); 184 185 extern void xfs_buf_ioend(xfs_buf_t *, int); 186 extern void xfs_buf_ioerror(xfs_buf_t *, int); 187 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 188 extern void xfs_buf_iorequest(xfs_buf_t *); 189 extern int xfs_buf_iowait(xfs_buf_t *); 190 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 191 xfs_buf_rw_t); 192 #define xfs_buf_zero(bp, off, len) \ 193 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 194 195 static inline int xfs_buf_geterror(xfs_buf_t *bp) 196 { 197 return bp ? bp->b_error : ENOMEM; 198 } 199 200 /* Buffer Utility Routines */ 201 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t); 202 203 /* Delayed Write Buffer Routines */ 204 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 205 extern int xfs_buf_delwri_submit(struct list_head *); 206 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 207 208 /* Buffer Daemon Setup Routines */ 209 extern int xfs_buf_init(void); 210 extern void xfs_buf_terminate(void); 211 212 #define XFS_BUF_ZEROFLAGS(bp) \ 213 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \ 214 XBF_SYNCIO|XBF_FUA|XBF_FLUSH)) 215 216 void xfs_buf_stale(struct xfs_buf *bp); 217 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) 218 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) 219 220 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) 221 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) 222 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) 223 224 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) 225 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) 226 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) 227 228 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) 229 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) 230 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) 231 232 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) 233 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) 234 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) 235 236 #define XFS_BUF_ADDR(bp) ((bp)->b_bn) 237 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno)) 238 239 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 240 { 241 atomic_set(&bp->b_lru_ref, lru_ref); 242 } 243 244 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 245 { 246 return atomic_read(&bp->b_pin_count); 247 } 248 249 static inline void xfs_buf_relse(xfs_buf_t *bp) 250 { 251 xfs_buf_unlock(bp); 252 xfs_buf_rele(bp); 253 } 254 255 /* 256 * Handling of buftargs. 257 */ 258 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 259 struct block_device *, int, const char *); 260 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 261 extern void xfs_wait_buftarg(xfs_buftarg_t *); 262 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int); 263 264 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 265 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 266 267 #endif /* __XFS_BUF_H__ */ 268