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 #define _XBF_LRU_DISPOSE (1 << 24)/* buffer being discarded */ 63 64 typedef unsigned int xfs_buf_flags_t; 65 66 #define XFS_BUF_FLAGS \ 67 { XBF_READ, "READ" }, \ 68 { XBF_WRITE, "WRITE" }, \ 69 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 70 { XBF_ASYNC, "ASYNC" }, \ 71 { XBF_DONE, "DONE" }, \ 72 { XBF_STALE, "STALE" }, \ 73 { XBF_SYNCIO, "SYNCIO" }, \ 74 { XBF_FUA, "FUA" }, \ 75 { XBF_FLUSH, "FLUSH" }, \ 76 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\ 77 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\ 78 { _XBF_PAGES, "PAGES" }, \ 79 { _XBF_KMEM, "KMEM" }, \ 80 { _XBF_DELWRI_Q, "DELWRI_Q" }, \ 81 { _XBF_COMPOUND, "COMPOUND" }, \ 82 { _XBF_LRU_DISPOSE, "LRU_DISPOSE" } 83 84 typedef struct xfs_buftarg { 85 dev_t bt_dev; 86 struct block_device *bt_bdev; 87 struct backing_dev_info *bt_bdi; 88 struct xfs_mount *bt_mount; 89 unsigned int bt_bsize; 90 unsigned int bt_sshift; 91 size_t bt_smask; 92 93 /* LRU control structures */ 94 struct shrinker bt_shrinker; 95 struct list_head bt_lru; 96 spinlock_t bt_lru_lock; 97 unsigned int bt_lru_nr; 98 } xfs_buftarg_t; 99 100 struct xfs_buf; 101 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 102 103 104 #define XB_PAGES 2 105 106 struct xfs_buf_map { 107 xfs_daddr_t bm_bn; /* block number for I/O */ 108 int bm_len; /* size of I/O */ 109 }; 110 111 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \ 112 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) }; 113 114 struct xfs_buf_ops { 115 void (*verify_read)(struct xfs_buf *); 116 void (*verify_write)(struct xfs_buf *); 117 }; 118 119 typedef struct xfs_buf { 120 /* 121 * first cacheline holds all the fields needed for an uncontended cache 122 * hit to be fully processed. The semaphore straddles the cacheline 123 * boundary, but the counter and lock sits on the first cacheline, 124 * which is the only bit that is touched if we hit the semaphore 125 * fast-path on locking. 126 */ 127 struct rb_node b_rbnode; /* rbtree node */ 128 xfs_daddr_t b_bn; /* block number of buffer */ 129 int b_length; /* size of buffer in BBs */ 130 atomic_t b_hold; /* reference count */ 131 atomic_t b_lru_ref; /* lru reclaim ref count */ 132 xfs_buf_flags_t b_flags; /* status flags */ 133 struct semaphore b_sema; /* semaphore for lockables */ 134 135 /* 136 * concurrent access to b_lru and b_lru_flags are protected by 137 * bt_lru_lock and not by b_sema 138 */ 139 struct list_head b_lru; /* lru list */ 140 xfs_buf_flags_t b_lru_flags; /* internal lru status flags */ 141 wait_queue_head_t b_waiters; /* unpin waiters */ 142 struct list_head b_list; 143 struct xfs_perag *b_pag; /* contains rbtree root */ 144 xfs_buftarg_t *b_target; /* buffer target (device) */ 145 void *b_addr; /* virtual address of buffer */ 146 struct work_struct b_iodone_work; 147 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 148 struct completion b_iowait; /* queue for I/O waiters */ 149 void *b_fspriv; 150 struct xfs_trans *b_transp; 151 struct page **b_pages; /* array of page pointers */ 152 struct page *b_page_array[XB_PAGES]; /* inline pages */ 153 struct xfs_buf_map *b_maps; /* compound buffer map */ 154 struct xfs_buf_map b_map; /* inline compound buffer map */ 155 int b_map_count; 156 int b_io_length; /* IO size in BBs */ 157 atomic_t b_pin_count; /* pin count */ 158 atomic_t b_io_remaining; /* #outstanding I/O requests */ 159 unsigned int b_page_count; /* size of page array */ 160 unsigned int b_offset; /* page offset in first page */ 161 unsigned short b_error; /* error code on I/O */ 162 const struct xfs_buf_ops *b_ops; 163 164 #ifdef XFS_BUF_LOCK_TRACKING 165 int b_last_holder; 166 #endif 167 } xfs_buf_t; 168 169 /* Finding and Reading Buffers */ 170 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, 171 struct xfs_buf_map *map, int nmaps, 172 xfs_buf_flags_t flags, struct xfs_buf *new_bp); 173 174 static inline struct xfs_buf * 175 xfs_incore( 176 struct xfs_buftarg *target, 177 xfs_daddr_t blkno, 178 size_t numblks, 179 xfs_buf_flags_t flags) 180 { 181 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 182 return _xfs_buf_find(target, &map, 1, flags, NULL); 183 } 184 185 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 186 struct xfs_buf_map *map, int nmaps, 187 xfs_buf_flags_t flags); 188 189 static inline struct xfs_buf * 190 xfs_buf_alloc( 191 struct xfs_buftarg *target, 192 xfs_daddr_t blkno, 193 size_t numblks, 194 xfs_buf_flags_t flags) 195 { 196 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 197 return _xfs_buf_alloc(target, &map, 1, flags); 198 } 199 200 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 201 struct xfs_buf_map *map, int nmaps, 202 xfs_buf_flags_t flags); 203 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 204 struct xfs_buf_map *map, int nmaps, 205 xfs_buf_flags_t flags, 206 const struct xfs_buf_ops *ops); 207 void xfs_buf_readahead_map(struct xfs_buftarg *target, 208 struct xfs_buf_map *map, int nmaps, 209 const struct xfs_buf_ops *ops); 210 211 static inline struct xfs_buf * 212 xfs_buf_get( 213 struct xfs_buftarg *target, 214 xfs_daddr_t blkno, 215 size_t numblks, 216 xfs_buf_flags_t flags) 217 { 218 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 219 return xfs_buf_get_map(target, &map, 1, flags); 220 } 221 222 static inline struct xfs_buf * 223 xfs_buf_read( 224 struct xfs_buftarg *target, 225 xfs_daddr_t blkno, 226 size_t numblks, 227 xfs_buf_flags_t flags, 228 const struct xfs_buf_ops *ops) 229 { 230 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 231 return xfs_buf_read_map(target, &map, 1, flags, ops); 232 } 233 234 static inline void 235 xfs_buf_readahead( 236 struct xfs_buftarg *target, 237 xfs_daddr_t blkno, 238 size_t numblks, 239 const struct xfs_buf_ops *ops) 240 { 241 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 242 return xfs_buf_readahead_map(target, &map, 1, ops); 243 } 244 245 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); 246 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 247 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 248 249 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 250 int flags); 251 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target, 252 xfs_daddr_t daddr, size_t numblks, int flags, 253 const struct xfs_buf_ops *ops); 254 void xfs_buf_hold(struct xfs_buf *bp); 255 256 /* Releasing Buffers */ 257 extern void xfs_buf_free(xfs_buf_t *); 258 extern void xfs_buf_rele(xfs_buf_t *); 259 260 /* Locking and Unlocking Buffers */ 261 extern int xfs_buf_trylock(xfs_buf_t *); 262 extern void xfs_buf_lock(xfs_buf_t *); 263 extern void xfs_buf_unlock(xfs_buf_t *); 264 #define xfs_buf_islocked(bp) \ 265 ((bp)->b_sema.count <= 0) 266 267 /* Buffer Read and Write Routines */ 268 extern int xfs_bwrite(struct xfs_buf *bp); 269 270 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *); 271 272 extern void xfs_buf_ioend(xfs_buf_t *, int); 273 extern void xfs_buf_ioerror(xfs_buf_t *, int); 274 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 275 extern void xfs_buf_iorequest(xfs_buf_t *); 276 extern int xfs_buf_iowait(xfs_buf_t *); 277 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 278 xfs_buf_rw_t); 279 #define xfs_buf_zero(bp, off, len) \ 280 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 281 282 static inline int xfs_buf_geterror(xfs_buf_t *bp) 283 { 284 return bp ? bp->b_error : ENOMEM; 285 } 286 287 /* Buffer Utility Routines */ 288 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t); 289 290 /* Delayed Write Buffer Routines */ 291 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 292 extern int xfs_buf_delwri_submit(struct list_head *); 293 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 294 295 /* Buffer Daemon Setup Routines */ 296 extern int xfs_buf_init(void); 297 extern void xfs_buf_terminate(void); 298 299 #define XFS_BUF_ZEROFLAGS(bp) \ 300 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \ 301 XBF_SYNCIO|XBF_FUA|XBF_FLUSH)) 302 303 void xfs_buf_stale(struct xfs_buf *bp); 304 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) 305 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) 306 307 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) 308 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) 309 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) 310 311 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) 312 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) 313 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) 314 315 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) 316 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) 317 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) 318 319 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) 320 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) 321 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) 322 323 /* 324 * These macros use the IO block map rather than b_bn. b_bn is now really 325 * just for the buffer cache index for cached buffers. As IO does not use b_bn 326 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 327 * map directly. Uncached buffers are not allowed to be discontiguous, so this 328 * is safe to do. 329 * 330 * In future, uncached buffers will pass the block number directly to the io 331 * request function and hence these macros will go away at that point. 332 */ 333 #define XFS_BUF_ADDR(bp) ((bp)->b_map.bm_bn) 334 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_map.bm_bn = (xfs_daddr_t)(bno)) 335 336 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 337 { 338 atomic_set(&bp->b_lru_ref, lru_ref); 339 } 340 341 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 342 { 343 return atomic_read(&bp->b_pin_count); 344 } 345 346 static inline void xfs_buf_relse(xfs_buf_t *bp) 347 { 348 xfs_buf_unlock(bp); 349 xfs_buf_rele(bp); 350 } 351 352 /* 353 * Handling of buftargs. 354 */ 355 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 356 struct block_device *, int, const char *); 357 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 358 extern void xfs_wait_buftarg(xfs_buftarg_t *); 359 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int); 360 361 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 362 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 363 364 #endif /* __XFS_BUF_H__ */ 365