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 #include <linux/list_lru.h> 29 30 /* 31 * Base types 32 */ 33 34 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL)) 35 36 typedef enum { 37 XBRW_READ = 1, /* transfer into target memory */ 38 XBRW_WRITE = 2, /* transfer from target memory */ 39 XBRW_ZERO = 3, /* Zero target memory */ 40 } xfs_buf_rw_t; 41 42 #define XBF_READ (1 << 0) /* buffer intended for reading from device */ 43 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */ 44 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */ 45 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */ 46 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */ 47 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */ 48 #define XBF_WRITE_FAIL (1 << 24)/* async writes have failed on this buffer */ 49 50 /* I/O hints for the BIO layer */ 51 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */ 52 #define XBF_FUA (1 << 11)/* force cache write through mode */ 53 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */ 54 55 /* flags used only as arguments to access routines */ 56 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */ 57 #define XBF_UNMAPPED (1 << 17)/* do not map the buffer */ 58 59 /* flags used only internally */ 60 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */ 61 #define _XBF_KMEM (1 << 21)/* backed by heap memory */ 62 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */ 63 #define _XBF_COMPOUND (1 << 23)/* compound buffer */ 64 65 typedef unsigned int xfs_buf_flags_t; 66 67 #define XFS_BUF_FLAGS \ 68 { XBF_READ, "READ" }, \ 69 { XBF_WRITE, "WRITE" }, \ 70 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 71 { XBF_ASYNC, "ASYNC" }, \ 72 { XBF_DONE, "DONE" }, \ 73 { XBF_STALE, "STALE" }, \ 74 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \ 75 { XBF_SYNCIO, "SYNCIO" }, \ 76 { XBF_FUA, "FUA" }, \ 77 { XBF_FLUSH, "FLUSH" }, \ 78 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\ 79 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\ 80 { _XBF_PAGES, "PAGES" }, \ 81 { _XBF_KMEM, "KMEM" }, \ 82 { _XBF_DELWRI_Q, "DELWRI_Q" }, \ 83 { _XBF_COMPOUND, "COMPOUND" } 84 85 86 /* 87 * Internal state flags. 88 */ 89 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */ 90 91 typedef struct xfs_buftarg { 92 dev_t bt_dev; 93 struct block_device *bt_bdev; 94 struct backing_dev_info *bt_bdi; 95 struct xfs_mount *bt_mount; 96 unsigned int bt_bsize; 97 unsigned int bt_sshift; 98 size_t bt_smask; 99 100 /* LRU control structures */ 101 struct shrinker bt_shrinker; 102 struct list_lru bt_lru; 103 } xfs_buftarg_t; 104 105 struct xfs_buf; 106 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 107 108 109 #define XB_PAGES 2 110 111 struct xfs_buf_map { 112 xfs_daddr_t bm_bn; /* block number for I/O */ 113 int bm_len; /* size of I/O */ 114 }; 115 116 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \ 117 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) }; 118 119 struct xfs_buf_ops { 120 void (*verify_read)(struct xfs_buf *); 121 void (*verify_write)(struct xfs_buf *); 122 }; 123 124 typedef struct xfs_buf { 125 /* 126 * first cacheline holds all the fields needed for an uncontended cache 127 * hit to be fully processed. The semaphore straddles the cacheline 128 * boundary, but the counter and lock sits on the first cacheline, 129 * which is the only bit that is touched if we hit the semaphore 130 * fast-path on locking. 131 */ 132 struct rb_node b_rbnode; /* rbtree node */ 133 xfs_daddr_t b_bn; /* block number of buffer */ 134 int b_length; /* size of buffer in BBs */ 135 atomic_t b_hold; /* reference count */ 136 atomic_t b_lru_ref; /* lru reclaim ref count */ 137 xfs_buf_flags_t b_flags; /* status flags */ 138 struct semaphore b_sema; /* semaphore for lockables */ 139 140 /* 141 * concurrent access to b_lru and b_lru_flags are protected by 142 * bt_lru_lock and not by b_sema 143 */ 144 struct list_head b_lru; /* lru list */ 145 spinlock_t b_lock; /* internal state lock */ 146 unsigned int b_state; /* internal state flags */ 147 wait_queue_head_t b_waiters; /* unpin waiters */ 148 struct list_head b_list; 149 struct xfs_perag *b_pag; /* contains rbtree root */ 150 xfs_buftarg_t *b_target; /* buffer target (device) */ 151 void *b_addr; /* virtual address of buffer */ 152 struct work_struct b_iodone_work; 153 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 154 struct completion b_iowait; /* queue for I/O waiters */ 155 void *b_fspriv; 156 struct xfs_trans *b_transp; 157 struct page **b_pages; /* array of page pointers */ 158 struct page *b_page_array[XB_PAGES]; /* inline pages */ 159 struct xfs_buf_map *b_maps; /* compound buffer map */ 160 struct xfs_buf_map __b_map; /* inline compound buffer map */ 161 int b_map_count; 162 int b_io_length; /* IO size in BBs */ 163 atomic_t b_pin_count; /* pin count */ 164 atomic_t b_io_remaining; /* #outstanding I/O requests */ 165 unsigned int b_page_count; /* size of page array */ 166 unsigned int b_offset; /* page offset in first page */ 167 unsigned short b_error; /* error code on I/O */ 168 const struct xfs_buf_ops *b_ops; 169 170 #ifdef XFS_BUF_LOCK_TRACKING 171 int b_last_holder; 172 #endif 173 } xfs_buf_t; 174 175 /* Finding and Reading Buffers */ 176 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, 177 struct xfs_buf_map *map, int nmaps, 178 xfs_buf_flags_t flags, struct xfs_buf *new_bp); 179 180 static inline struct xfs_buf * 181 xfs_incore( 182 struct xfs_buftarg *target, 183 xfs_daddr_t blkno, 184 size_t numblks, 185 xfs_buf_flags_t flags) 186 { 187 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 188 return _xfs_buf_find(target, &map, 1, flags, NULL); 189 } 190 191 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 192 struct xfs_buf_map *map, int nmaps, 193 xfs_buf_flags_t flags); 194 195 static inline struct xfs_buf * 196 xfs_buf_alloc( 197 struct xfs_buftarg *target, 198 xfs_daddr_t blkno, 199 size_t numblks, 200 xfs_buf_flags_t flags) 201 { 202 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 203 return _xfs_buf_alloc(target, &map, 1, flags); 204 } 205 206 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 207 struct xfs_buf_map *map, int nmaps, 208 xfs_buf_flags_t flags); 209 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 210 struct xfs_buf_map *map, int nmaps, 211 xfs_buf_flags_t flags, 212 const struct xfs_buf_ops *ops); 213 void xfs_buf_readahead_map(struct xfs_buftarg *target, 214 struct xfs_buf_map *map, int nmaps, 215 const struct xfs_buf_ops *ops); 216 217 static inline struct xfs_buf * 218 xfs_buf_get( 219 struct xfs_buftarg *target, 220 xfs_daddr_t blkno, 221 size_t numblks, 222 xfs_buf_flags_t flags) 223 { 224 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 225 return xfs_buf_get_map(target, &map, 1, flags); 226 } 227 228 static inline struct xfs_buf * 229 xfs_buf_read( 230 struct xfs_buftarg *target, 231 xfs_daddr_t blkno, 232 size_t numblks, 233 xfs_buf_flags_t flags, 234 const struct xfs_buf_ops *ops) 235 { 236 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 237 return xfs_buf_read_map(target, &map, 1, flags, ops); 238 } 239 240 static inline void 241 xfs_buf_readahead( 242 struct xfs_buftarg *target, 243 xfs_daddr_t blkno, 244 size_t numblks, 245 const struct xfs_buf_ops *ops) 246 { 247 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 248 return xfs_buf_readahead_map(target, &map, 1, ops); 249 } 250 251 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); 252 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 253 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 254 255 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 256 int flags); 257 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target, 258 xfs_daddr_t daddr, size_t numblks, int flags, 259 const struct xfs_buf_ops *ops); 260 void xfs_buf_hold(struct xfs_buf *bp); 261 262 /* Releasing Buffers */ 263 extern void xfs_buf_free(xfs_buf_t *); 264 extern void xfs_buf_rele(xfs_buf_t *); 265 266 /* Locking and Unlocking Buffers */ 267 extern int xfs_buf_trylock(xfs_buf_t *); 268 extern void xfs_buf_lock(xfs_buf_t *); 269 extern void xfs_buf_unlock(xfs_buf_t *); 270 #define xfs_buf_islocked(bp) \ 271 ((bp)->b_sema.count <= 0) 272 273 /* Buffer Read and Write Routines */ 274 extern int xfs_bwrite(struct xfs_buf *bp); 275 extern void xfs_buf_ioend(xfs_buf_t *, int); 276 extern void xfs_buf_ioerror(xfs_buf_t *, int); 277 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 278 extern void xfs_buf_iorequest(xfs_buf_t *); 279 extern int xfs_buf_iowait(xfs_buf_t *); 280 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 281 xfs_buf_rw_t); 282 #define xfs_buf_zero(bp, off, len) \ 283 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 284 285 extern int xfs_bioerror_relse(struct xfs_buf *); 286 287 static inline int xfs_buf_geterror(xfs_buf_t *bp) 288 { 289 return bp ? bp->b_error : ENOMEM; 290 } 291 292 /* Buffer Utility Routines */ 293 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t); 294 295 /* Delayed Write Buffer Routines */ 296 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 297 extern int xfs_buf_delwri_submit(struct list_head *); 298 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 299 300 /* Buffer Daemon Setup Routines */ 301 extern int xfs_buf_init(void); 302 extern void xfs_buf_terminate(void); 303 304 #define XFS_BUF_ZEROFLAGS(bp) \ 305 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \ 306 XBF_SYNCIO|XBF_FUA|XBF_FLUSH| \ 307 XBF_WRITE_FAIL)) 308 309 void xfs_buf_stale(struct xfs_buf *bp); 310 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) 311 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) 312 313 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) 314 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) 315 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) 316 317 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) 318 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) 319 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) 320 321 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) 322 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) 323 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) 324 325 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) 326 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) 327 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) 328 329 /* 330 * These macros use the IO block map rather than b_bn. b_bn is now really 331 * just for the buffer cache index for cached buffers. As IO does not use b_bn 332 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 333 * map directly. Uncached buffers are not allowed to be discontiguous, so this 334 * is safe to do. 335 * 336 * In future, uncached buffers will pass the block number directly to the io 337 * request function and hence these macros will go away at that point. 338 */ 339 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) 340 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno)) 341 342 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 343 { 344 atomic_set(&bp->b_lru_ref, lru_ref); 345 } 346 347 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 348 { 349 return atomic_read(&bp->b_pin_count); 350 } 351 352 static inline void xfs_buf_relse(xfs_buf_t *bp) 353 { 354 xfs_buf_unlock(bp); 355 xfs_buf_rele(bp); 356 } 357 358 /* 359 * Handling of buftargs. 360 */ 361 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 362 struct block_device *, int, const char *); 363 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 364 extern void xfs_wait_buftarg(xfs_buftarg_t *); 365 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int); 366 367 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 368 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 369 370 #endif /* __XFS_BUF_H__ */ 371