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 #define _XBF_COMPOUND (1 << 23)/* compound buffer */ 62 63 typedef unsigned int xfs_buf_flags_t; 64 65 #define XFS_BUF_FLAGS \ 66 { XBF_READ, "READ" }, \ 67 { XBF_WRITE, "WRITE" }, \ 68 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 69 { XBF_ASYNC, "ASYNC" }, \ 70 { XBF_DONE, "DONE" }, \ 71 { XBF_STALE, "STALE" }, \ 72 { XBF_SYNCIO, "SYNCIO" }, \ 73 { XBF_FUA, "FUA" }, \ 74 { XBF_FLUSH, "FLUSH" }, \ 75 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\ 76 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\ 77 { _XBF_PAGES, "PAGES" }, \ 78 { _XBF_KMEM, "KMEM" }, \ 79 { _XBF_DELWRI_Q, "DELWRI_Q" }, \ 80 { _XBF_COMPOUND, "COMPOUND" } 81 82 typedef struct xfs_buftarg { 83 dev_t bt_dev; 84 struct block_device *bt_bdev; 85 struct backing_dev_info *bt_bdi; 86 struct xfs_mount *bt_mount; 87 unsigned int bt_bsize; 88 unsigned int bt_sshift; 89 size_t bt_smask; 90 91 /* LRU control structures */ 92 struct shrinker bt_shrinker; 93 struct list_head bt_lru; 94 spinlock_t bt_lru_lock; 95 unsigned int bt_lru_nr; 96 } xfs_buftarg_t; 97 98 struct xfs_buf; 99 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 100 101 #define XB_PAGES 2 102 103 struct xfs_buf_map { 104 xfs_daddr_t bm_bn; /* block number for I/O */ 105 int bm_len; /* size of I/O */ 106 }; 107 108 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \ 109 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) }; 110 111 typedef struct xfs_buf { 112 /* 113 * first cacheline holds all the fields needed for an uncontended cache 114 * hit to be fully processed. The semaphore straddles the cacheline 115 * boundary, but the counter and lock sits on the first cacheline, 116 * which is the only bit that is touched if we hit the semaphore 117 * fast-path on locking. 118 */ 119 struct rb_node b_rbnode; /* rbtree node */ 120 xfs_daddr_t b_bn; /* block number of buffer */ 121 int b_length; /* size of buffer in BBs */ 122 atomic_t b_hold; /* reference count */ 123 atomic_t b_lru_ref; /* lru reclaim ref count */ 124 xfs_buf_flags_t b_flags; /* status flags */ 125 struct semaphore b_sema; /* semaphore for lockables */ 126 127 struct list_head b_lru; /* lru list */ 128 wait_queue_head_t b_waiters; /* unpin waiters */ 129 struct list_head b_list; 130 struct xfs_perag *b_pag; /* contains rbtree root */ 131 xfs_buftarg_t *b_target; /* buffer target (device) */ 132 void *b_addr; /* virtual address of buffer */ 133 struct work_struct b_iodone_work; 134 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 135 struct completion b_iowait; /* queue for I/O waiters */ 136 void *b_fspriv; 137 struct xfs_trans *b_transp; 138 struct page **b_pages; /* array of page pointers */ 139 struct page *b_page_array[XB_PAGES]; /* inline pages */ 140 struct xfs_buf_map *b_maps; /* compound buffer map */ 141 struct xfs_buf_map b_map; /* inline compound buffer map */ 142 int b_map_count; 143 int b_io_length; /* IO size in BBs */ 144 atomic_t b_pin_count; /* pin count */ 145 atomic_t b_io_remaining; /* #outstanding I/O requests */ 146 unsigned int b_page_count; /* size of page array */ 147 unsigned int b_offset; /* page offset in first page */ 148 unsigned short b_error; /* error code on I/O */ 149 150 #ifdef XFS_BUF_LOCK_TRACKING 151 int b_last_holder; 152 #endif 153 } xfs_buf_t; 154 155 156 /* Finding and Reading Buffers */ 157 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, 158 struct xfs_buf_map *map, int nmaps, 159 xfs_buf_flags_t flags, struct xfs_buf *new_bp); 160 161 static inline struct xfs_buf * 162 xfs_incore( 163 struct xfs_buftarg *target, 164 xfs_daddr_t blkno, 165 size_t numblks, 166 xfs_buf_flags_t flags) 167 { 168 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 169 return _xfs_buf_find(target, &map, 1, flags, NULL); 170 } 171 172 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 173 struct xfs_buf_map *map, int nmaps, 174 xfs_buf_flags_t flags); 175 176 static inline struct xfs_buf * 177 xfs_buf_alloc( 178 struct xfs_buftarg *target, 179 xfs_daddr_t blkno, 180 size_t numblks, 181 xfs_buf_flags_t flags) 182 { 183 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 184 return _xfs_buf_alloc(target, &map, 1, flags); 185 } 186 187 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 188 struct xfs_buf_map *map, int nmaps, 189 xfs_buf_flags_t flags); 190 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 191 struct xfs_buf_map *map, int nmaps, 192 xfs_buf_flags_t flags); 193 void xfs_buf_readahead_map(struct xfs_buftarg *target, 194 struct xfs_buf_map *map, int nmaps); 195 196 static inline struct xfs_buf * 197 xfs_buf_get( 198 struct xfs_buftarg *target, 199 xfs_daddr_t blkno, 200 size_t numblks, 201 xfs_buf_flags_t flags) 202 { 203 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 204 return xfs_buf_get_map(target, &map, 1, flags); 205 } 206 207 static inline struct xfs_buf * 208 xfs_buf_read( 209 struct xfs_buftarg *target, 210 xfs_daddr_t blkno, 211 size_t numblks, 212 xfs_buf_flags_t flags) 213 { 214 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 215 return xfs_buf_read_map(target, &map, 1, flags); 216 } 217 218 static inline void 219 xfs_buf_readahead( 220 struct xfs_buftarg *target, 221 xfs_daddr_t blkno, 222 size_t numblks) 223 { 224 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 225 return xfs_buf_readahead_map(target, &map, 1); 226 } 227 228 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); 229 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 230 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 231 232 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 233 int flags); 234 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target, 235 xfs_daddr_t daddr, size_t numblks, int flags); 236 void xfs_buf_hold(struct xfs_buf *bp); 237 238 /* Releasing Buffers */ 239 extern void xfs_buf_free(xfs_buf_t *); 240 extern void xfs_buf_rele(xfs_buf_t *); 241 242 /* Locking and Unlocking Buffers */ 243 extern int xfs_buf_trylock(xfs_buf_t *); 244 extern void xfs_buf_lock(xfs_buf_t *); 245 extern void xfs_buf_unlock(xfs_buf_t *); 246 #define xfs_buf_islocked(bp) \ 247 ((bp)->b_sema.count <= 0) 248 249 /* Buffer Read and Write Routines */ 250 extern int xfs_bwrite(struct xfs_buf *bp); 251 252 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *); 253 254 extern void xfs_buf_ioend(xfs_buf_t *, int); 255 extern void xfs_buf_ioerror(xfs_buf_t *, int); 256 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 257 extern void xfs_buf_iorequest(xfs_buf_t *); 258 extern int xfs_buf_iowait(xfs_buf_t *); 259 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 260 xfs_buf_rw_t); 261 #define xfs_buf_zero(bp, off, len) \ 262 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 263 264 static inline int xfs_buf_geterror(xfs_buf_t *bp) 265 { 266 return bp ? bp->b_error : ENOMEM; 267 } 268 269 /* Buffer Utility Routines */ 270 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t); 271 272 /* Delayed Write Buffer Routines */ 273 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 274 extern int xfs_buf_delwri_submit(struct list_head *); 275 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 276 277 /* Buffer Daemon Setup Routines */ 278 extern int xfs_buf_init(void); 279 extern void xfs_buf_terminate(void); 280 281 #define XFS_BUF_ZEROFLAGS(bp) \ 282 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \ 283 XBF_SYNCIO|XBF_FUA|XBF_FLUSH)) 284 285 void xfs_buf_stale(struct xfs_buf *bp); 286 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) 287 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) 288 289 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) 290 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) 291 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) 292 293 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) 294 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) 295 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) 296 297 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) 298 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) 299 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) 300 301 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) 302 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) 303 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) 304 305 /* 306 * These macros use the IO block map rather than b_bn. b_bn is now really 307 * just for the buffer cache index for cached buffers. As IO does not use b_bn 308 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 309 * map directly. Uncached buffers are not allowed to be discontiguous, so this 310 * is safe to do. 311 * 312 * In future, uncached buffers will pass the block number directly to the io 313 * request function and hence these macros will go away at that point. 314 */ 315 #define XFS_BUF_ADDR(bp) ((bp)->b_map.bm_bn) 316 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_map.bm_bn = (xfs_daddr_t)(bno)) 317 318 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 319 { 320 atomic_set(&bp->b_lru_ref, lru_ref); 321 } 322 323 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 324 { 325 return atomic_read(&bp->b_pin_count); 326 } 327 328 static inline void xfs_buf_relse(xfs_buf_t *bp) 329 { 330 xfs_buf_unlock(bp); 331 xfs_buf_rele(bp); 332 } 333 334 /* 335 * Handling of buftargs. 336 */ 337 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 338 struct block_device *, int, const char *); 339 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 340 extern void xfs_wait_buftarg(xfs_buftarg_t *); 341 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int); 342 343 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 344 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 345 346 #endif /* __XFS_BUF_H__ */ 347