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/dax.h> 27 #include <linux/buffer_head.h> 28 #include <linux/uio.h> 29 #include <linux/list_lru.h> 30 31 /* 32 * Base types 33 */ 34 35 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL)) 36 37 typedef enum { 38 XBRW_READ = 1, /* transfer into target memory */ 39 XBRW_WRITE = 2, /* transfer from target memory */ 40 XBRW_ZERO = 3, /* Zero target memory */ 41 } xfs_buf_rw_t; 42 43 #define XBF_READ (1 << 0) /* buffer intended for reading from device */ 44 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */ 45 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */ 46 #define XBF_NO_IOACCT (1 << 3) /* bypass I/O accounting (non-LRU bufs) */ 47 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */ 48 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */ 49 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */ 50 #define XBF_WRITE_FAIL (1 << 24)/* async writes have failed on this buffer */ 51 52 /* I/O hints for the BIO layer */ 53 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */ 54 #define XBF_FUA (1 << 11)/* force cache write through mode */ 55 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */ 56 57 /* flags used only as arguments to access routines */ 58 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */ 59 #define XBF_UNMAPPED (1 << 17)/* do not map the buffer */ 60 61 /* flags used only internally */ 62 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */ 63 #define _XBF_KMEM (1 << 21)/* backed by heap memory */ 64 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */ 65 #define _XBF_COMPOUND (1 << 23)/* compound buffer */ 66 #define _XBF_IN_FLIGHT (1 << 25) /* I/O in flight, for accounting purposes */ 67 68 typedef unsigned int xfs_buf_flags_t; 69 70 #define XFS_BUF_FLAGS \ 71 { XBF_READ, "READ" }, \ 72 { XBF_WRITE, "WRITE" }, \ 73 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 74 { XBF_ASYNC, "ASYNC" }, \ 75 { XBF_DONE, "DONE" }, \ 76 { XBF_STALE, "STALE" }, \ 77 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \ 78 { XBF_SYNCIO, "SYNCIO" }, \ 79 { XBF_FUA, "FUA" }, \ 80 { XBF_FLUSH, "FLUSH" }, \ 81 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\ 82 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\ 83 { _XBF_PAGES, "PAGES" }, \ 84 { _XBF_KMEM, "KMEM" }, \ 85 { _XBF_DELWRI_Q, "DELWRI_Q" }, \ 86 { _XBF_COMPOUND, "COMPOUND" }, \ 87 { _XBF_IN_FLIGHT, "IN_FLIGHT" } 88 89 90 /* 91 * Internal state flags. 92 */ 93 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */ 94 95 /* 96 * The xfs_buftarg contains 2 notions of "sector size" - 97 * 98 * 1) The metadata sector size, which is the minimum unit and 99 * alignment of IO which will be performed by metadata operations. 100 * 2) The device logical sector size 101 * 102 * The first is specified at mkfs time, and is stored on-disk in the 103 * superblock's sb_sectsize. 104 * 105 * The latter is derived from the underlying device, and controls direct IO 106 * alignment constraints. 107 */ 108 typedef struct xfs_buftarg { 109 dev_t bt_dev; 110 struct block_device *bt_bdev; 111 struct backing_dev_info *bt_bdi; 112 struct xfs_mount *bt_mount; 113 unsigned int bt_meta_sectorsize; 114 size_t bt_meta_sectormask; 115 size_t bt_logical_sectorsize; 116 size_t bt_logical_sectormask; 117 118 /* LRU control structures */ 119 struct shrinker bt_shrinker; 120 struct list_lru bt_lru; 121 122 struct percpu_counter bt_io_count; 123 } xfs_buftarg_t; 124 125 struct xfs_buf; 126 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 127 128 129 #define XB_PAGES 2 130 131 struct xfs_buf_map { 132 xfs_daddr_t bm_bn; /* block number for I/O */ 133 int bm_len; /* size of I/O */ 134 }; 135 136 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \ 137 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) }; 138 139 struct xfs_buf_ops { 140 char *name; 141 void (*verify_read)(struct xfs_buf *); 142 void (*verify_write)(struct xfs_buf *); 143 }; 144 145 typedef struct xfs_buf { 146 /* 147 * first cacheline holds all the fields needed for an uncontended cache 148 * hit to be fully processed. The semaphore straddles the cacheline 149 * boundary, but the counter and lock sits on the first cacheline, 150 * which is the only bit that is touched if we hit the semaphore 151 * fast-path on locking. 152 */ 153 struct rb_node b_rbnode; /* rbtree node */ 154 xfs_daddr_t b_bn; /* block number of buffer */ 155 int b_length; /* size of buffer in BBs */ 156 atomic_t b_hold; /* reference count */ 157 atomic_t b_lru_ref; /* lru reclaim ref count */ 158 xfs_buf_flags_t b_flags; /* status flags */ 159 struct semaphore b_sema; /* semaphore for lockables */ 160 161 /* 162 * concurrent access to b_lru and b_lru_flags are protected by 163 * bt_lru_lock and not by b_sema 164 */ 165 struct list_head b_lru; /* lru list */ 166 spinlock_t b_lock; /* internal state lock */ 167 unsigned int b_state; /* internal state flags */ 168 int b_io_error; /* internal IO error state */ 169 wait_queue_head_t b_waiters; /* unpin waiters */ 170 struct list_head b_list; 171 struct xfs_perag *b_pag; /* contains rbtree root */ 172 xfs_buftarg_t *b_target; /* buffer target (device) */ 173 void *b_addr; /* virtual address of buffer */ 174 struct work_struct b_ioend_work; 175 struct workqueue_struct *b_ioend_wq; /* I/O completion wq */ 176 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 177 struct completion b_iowait; /* queue for I/O waiters */ 178 void *b_fspriv; 179 struct xfs_trans *b_transp; 180 struct page **b_pages; /* array of page pointers */ 181 struct page *b_page_array[XB_PAGES]; /* inline pages */ 182 struct xfs_buf_map *b_maps; /* compound buffer map */ 183 struct xfs_buf_map __b_map; /* inline compound buffer map */ 184 int b_map_count; 185 int b_io_length; /* IO size in BBs */ 186 atomic_t b_pin_count; /* pin count */ 187 atomic_t b_io_remaining; /* #outstanding I/O requests */ 188 unsigned int b_page_count; /* size of page array */ 189 unsigned int b_offset; /* page offset in first page */ 190 int b_error; /* error code on I/O */ 191 192 /* 193 * async write failure retry count. Initialised to zero on the first 194 * failure, then when it exceeds the maximum configured without a 195 * success the write is considered to be failed permanently and the 196 * iodone handler will take appropriate action. 197 * 198 * For retry timeouts, we record the jiffie of the first failure. This 199 * means that we can change the retry timeout for buffers already under 200 * I/O and thus avoid getting stuck in a retry loop with a long timeout. 201 * 202 * last_error is used to ensure that we are getting repeated errors, not 203 * different errors. e.g. a block device might change ENOSPC to EIO when 204 * a failure timeout occurs, so we want to re-initialise the error 205 * retry behaviour appropriately when that happens. 206 */ 207 int b_retries; 208 unsigned long b_first_retry_time; /* in jiffies */ 209 int b_last_error; 210 211 const struct xfs_buf_ops *b_ops; 212 213 #ifdef XFS_BUF_LOCK_TRACKING 214 int b_last_holder; 215 #endif 216 } xfs_buf_t; 217 218 /* Finding and Reading Buffers */ 219 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, 220 struct xfs_buf_map *map, int nmaps, 221 xfs_buf_flags_t flags, struct xfs_buf *new_bp); 222 223 static inline struct xfs_buf * 224 xfs_incore( 225 struct xfs_buftarg *target, 226 xfs_daddr_t blkno, 227 size_t numblks, 228 xfs_buf_flags_t flags) 229 { 230 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 231 return _xfs_buf_find(target, &map, 1, flags, NULL); 232 } 233 234 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 235 struct xfs_buf_map *map, int nmaps, 236 xfs_buf_flags_t flags); 237 238 static inline struct xfs_buf * 239 xfs_buf_alloc( 240 struct xfs_buftarg *target, 241 xfs_daddr_t blkno, 242 size_t numblks, 243 xfs_buf_flags_t flags) 244 { 245 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 246 return _xfs_buf_alloc(target, &map, 1, flags); 247 } 248 249 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 250 struct xfs_buf_map *map, int nmaps, 251 xfs_buf_flags_t flags); 252 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 253 struct xfs_buf_map *map, int nmaps, 254 xfs_buf_flags_t flags, 255 const struct xfs_buf_ops *ops); 256 void xfs_buf_readahead_map(struct xfs_buftarg *target, 257 struct xfs_buf_map *map, int nmaps, 258 const struct xfs_buf_ops *ops); 259 260 static inline struct xfs_buf * 261 xfs_buf_get( 262 struct xfs_buftarg *target, 263 xfs_daddr_t blkno, 264 size_t numblks, 265 xfs_buf_flags_t flags) 266 { 267 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 268 return xfs_buf_get_map(target, &map, 1, flags); 269 } 270 271 static inline struct xfs_buf * 272 xfs_buf_read( 273 struct xfs_buftarg *target, 274 xfs_daddr_t blkno, 275 size_t numblks, 276 xfs_buf_flags_t flags, 277 const struct xfs_buf_ops *ops) 278 { 279 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 280 return xfs_buf_read_map(target, &map, 1, flags, ops); 281 } 282 283 static inline void 284 xfs_buf_readahead( 285 struct xfs_buftarg *target, 286 xfs_daddr_t blkno, 287 size_t numblks, 288 const struct xfs_buf_ops *ops) 289 { 290 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 291 return xfs_buf_readahead_map(target, &map, 1, ops); 292 } 293 294 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); 295 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 296 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 297 298 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 299 int flags); 300 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr, 301 size_t numblks, int flags, struct xfs_buf **bpp, 302 const struct xfs_buf_ops *ops); 303 void xfs_buf_hold(struct xfs_buf *bp); 304 305 /* Releasing Buffers */ 306 extern void xfs_buf_free(xfs_buf_t *); 307 extern void xfs_buf_rele(xfs_buf_t *); 308 309 /* Locking and Unlocking Buffers */ 310 extern int xfs_buf_trylock(xfs_buf_t *); 311 extern void xfs_buf_lock(xfs_buf_t *); 312 extern void xfs_buf_unlock(xfs_buf_t *); 313 #define xfs_buf_islocked(bp) \ 314 ((bp)->b_sema.count <= 0) 315 316 /* Buffer Read and Write Routines */ 317 extern int xfs_bwrite(struct xfs_buf *bp); 318 extern void xfs_buf_ioend(struct xfs_buf *bp); 319 extern void xfs_buf_ioerror(xfs_buf_t *, int); 320 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 321 extern void xfs_buf_submit(struct xfs_buf *bp); 322 extern int xfs_buf_submit_wait(struct xfs_buf *bp); 323 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 324 xfs_buf_rw_t); 325 #define xfs_buf_zero(bp, off, len) \ 326 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 327 328 /* Buffer Utility Routines */ 329 extern void *xfs_buf_offset(struct xfs_buf *, size_t); 330 extern void xfs_buf_stale(struct xfs_buf *bp); 331 332 /* Delayed Write Buffer Routines */ 333 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 334 extern int xfs_buf_delwri_submit(struct list_head *); 335 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 336 337 /* Buffer Daemon Setup Routines */ 338 extern int xfs_buf_init(void); 339 extern void xfs_buf_terminate(void); 340 341 /* 342 * These macros use the IO block map rather than b_bn. b_bn is now really 343 * just for the buffer cache index for cached buffers. As IO does not use b_bn 344 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 345 * map directly. Uncached buffers are not allowed to be discontiguous, so this 346 * is safe to do. 347 * 348 * In future, uncached buffers will pass the block number directly to the io 349 * request function and hence these macros will go away at that point. 350 */ 351 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) 352 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno)) 353 354 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 355 { 356 atomic_set(&bp->b_lru_ref, lru_ref); 357 } 358 359 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 360 { 361 return atomic_read(&bp->b_pin_count); 362 } 363 364 static inline void xfs_buf_relse(xfs_buf_t *bp) 365 { 366 xfs_buf_unlock(bp); 367 xfs_buf_rele(bp); 368 } 369 370 static inline int 371 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 372 { 373 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), 374 cksum_offset); 375 } 376 377 static inline void 378 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 379 { 380 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), 381 cksum_offset); 382 } 383 384 /* 385 * Handling of buftargs. 386 */ 387 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 388 struct block_device *); 389 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 390 extern void xfs_wait_buftarg(xfs_buftarg_t *); 391 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); 392 393 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 394 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 395 396 #endif /* __XFS_BUF_H__ */ 397