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_NO_IOACCT, "NO_IOACCT" }, \ 75 { XBF_ASYNC, "ASYNC" }, \ 76 { XBF_DONE, "DONE" }, \ 77 { XBF_STALE, "STALE" }, \ 78 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \ 79 { XBF_SYNCIO, "SYNCIO" }, \ 80 { XBF_FUA, "FUA" }, \ 81 { XBF_FLUSH, "FLUSH" }, \ 82 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\ 83 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\ 84 { _XBF_PAGES, "PAGES" }, \ 85 { _XBF_KMEM, "KMEM" }, \ 86 { _XBF_DELWRI_Q, "DELWRI_Q" }, \ 87 { _XBF_COMPOUND, "COMPOUND" }, \ 88 { _XBF_IN_FLIGHT, "IN_FLIGHT" } 89 90 91 /* 92 * Internal state flags. 93 */ 94 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */ 95 96 /* 97 * The xfs_buftarg contains 2 notions of "sector size" - 98 * 99 * 1) The metadata sector size, which is the minimum unit and 100 * alignment of IO which will be performed by metadata operations. 101 * 2) The device logical sector size 102 * 103 * The first is specified at mkfs time, and is stored on-disk in the 104 * superblock's sb_sectsize. 105 * 106 * The latter is derived from the underlying device, and controls direct IO 107 * alignment constraints. 108 */ 109 typedef struct xfs_buftarg { 110 dev_t bt_dev; 111 struct block_device *bt_bdev; 112 struct backing_dev_info *bt_bdi; 113 struct xfs_mount *bt_mount; 114 unsigned int bt_meta_sectorsize; 115 size_t bt_meta_sectormask; 116 size_t bt_logical_sectorsize; 117 size_t bt_logical_sectormask; 118 119 /* LRU control structures */ 120 struct shrinker bt_shrinker; 121 struct list_lru bt_lru; 122 123 struct percpu_counter bt_io_count; 124 } xfs_buftarg_t; 125 126 struct xfs_buf; 127 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 128 129 130 #define XB_PAGES 2 131 132 struct xfs_buf_map { 133 xfs_daddr_t bm_bn; /* block number for I/O */ 134 int bm_len; /* size of I/O */ 135 }; 136 137 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \ 138 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) }; 139 140 struct xfs_buf_ops { 141 char *name; 142 void (*verify_read)(struct xfs_buf *); 143 void (*verify_write)(struct xfs_buf *); 144 }; 145 146 typedef struct xfs_buf { 147 /* 148 * first cacheline holds all the fields needed for an uncontended cache 149 * hit to be fully processed. The semaphore straddles the cacheline 150 * boundary, but the counter and lock sits on the first cacheline, 151 * which is the only bit that is touched if we hit the semaphore 152 * fast-path on locking. 153 */ 154 struct rhash_head b_rhash_head; /* pag buffer hash node */ 155 xfs_daddr_t b_bn; /* block number of buffer */ 156 int b_length; /* size of buffer in BBs */ 157 atomic_t b_hold; /* reference count */ 158 atomic_t b_lru_ref; /* lru reclaim ref count */ 159 xfs_buf_flags_t b_flags; /* status flags */ 160 struct semaphore b_sema; /* semaphore for lockables */ 161 162 /* 163 * concurrent access to b_lru and b_lru_flags are protected by 164 * bt_lru_lock and not by b_sema 165 */ 166 struct list_head b_lru; /* lru list */ 167 spinlock_t b_lock; /* internal state lock */ 168 unsigned int b_state; /* internal state flags */ 169 int b_io_error; /* internal IO error state */ 170 wait_queue_head_t b_waiters; /* unpin waiters */ 171 struct list_head b_list; 172 struct xfs_perag *b_pag; /* contains rbtree root */ 173 xfs_buftarg_t *b_target; /* buffer target (device) */ 174 void *b_addr; /* virtual address of buffer */ 175 struct work_struct b_ioend_work; 176 struct workqueue_struct *b_ioend_wq; /* I/O completion wq */ 177 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 178 struct completion b_iowait; /* queue for I/O waiters */ 179 void *b_fspriv; 180 struct xfs_trans *b_transp; 181 struct page **b_pages; /* array of page pointers */ 182 struct page *b_page_array[XB_PAGES]; /* inline pages */ 183 struct xfs_buf_map *b_maps; /* compound buffer map */ 184 struct xfs_buf_map __b_map; /* inline compound buffer map */ 185 int b_map_count; 186 int b_io_length; /* IO size in BBs */ 187 atomic_t b_pin_count; /* pin count */ 188 atomic_t b_io_remaining; /* #outstanding I/O requests */ 189 unsigned int b_page_count; /* size of page array */ 190 unsigned int b_offset; /* page offset in first page */ 191 int b_error; /* error code on I/O */ 192 193 /* 194 * async write failure retry count. Initialised to zero on the first 195 * failure, then when it exceeds the maximum configured without a 196 * success the write is considered to be failed permanently and the 197 * iodone handler will take appropriate action. 198 * 199 * For retry timeouts, we record the jiffie of the first failure. This 200 * means that we can change the retry timeout for buffers already under 201 * I/O and thus avoid getting stuck in a retry loop with a long timeout. 202 * 203 * last_error is used to ensure that we are getting repeated errors, not 204 * different errors. e.g. a block device might change ENOSPC to EIO when 205 * a failure timeout occurs, so we want to re-initialise the error 206 * retry behaviour appropriately when that happens. 207 */ 208 int b_retries; 209 unsigned long b_first_retry_time; /* in jiffies */ 210 int b_last_error; 211 212 const struct xfs_buf_ops *b_ops; 213 214 #ifdef XFS_BUF_LOCK_TRACKING 215 int b_last_holder; 216 #endif 217 } xfs_buf_t; 218 219 /* Finding and Reading Buffers */ 220 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, 221 struct xfs_buf_map *map, int nmaps, 222 xfs_buf_flags_t flags, struct xfs_buf *new_bp); 223 224 static inline struct xfs_buf * 225 xfs_incore( 226 struct xfs_buftarg *target, 227 xfs_daddr_t blkno, 228 size_t numblks, 229 xfs_buf_flags_t flags) 230 { 231 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 232 return _xfs_buf_find(target, &map, 1, flags, NULL); 233 } 234 235 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 236 struct xfs_buf_map *map, int nmaps, 237 xfs_buf_flags_t flags); 238 239 static inline struct xfs_buf * 240 xfs_buf_alloc( 241 struct xfs_buftarg *target, 242 xfs_daddr_t blkno, 243 size_t numblks, 244 xfs_buf_flags_t flags) 245 { 246 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 247 return _xfs_buf_alloc(target, &map, 1, flags); 248 } 249 250 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 251 struct xfs_buf_map *map, int nmaps, 252 xfs_buf_flags_t flags); 253 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 254 struct xfs_buf_map *map, int nmaps, 255 xfs_buf_flags_t flags, 256 const struct xfs_buf_ops *ops); 257 void xfs_buf_readahead_map(struct xfs_buftarg *target, 258 struct xfs_buf_map *map, int nmaps, 259 const struct xfs_buf_ops *ops); 260 261 static inline struct xfs_buf * 262 xfs_buf_get( 263 struct xfs_buftarg *target, 264 xfs_daddr_t blkno, 265 size_t numblks, 266 xfs_buf_flags_t flags) 267 { 268 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 269 return xfs_buf_get_map(target, &map, 1, flags); 270 } 271 272 static inline struct xfs_buf * 273 xfs_buf_read( 274 struct xfs_buftarg *target, 275 xfs_daddr_t blkno, 276 size_t numblks, 277 xfs_buf_flags_t flags, 278 const struct xfs_buf_ops *ops) 279 { 280 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 281 return xfs_buf_read_map(target, &map, 1, flags, ops); 282 } 283 284 static inline void 285 xfs_buf_readahead( 286 struct xfs_buftarg *target, 287 xfs_daddr_t blkno, 288 size_t numblks, 289 const struct xfs_buf_ops *ops) 290 { 291 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 292 return xfs_buf_readahead_map(target, &map, 1, ops); 293 } 294 295 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); 296 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 297 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 298 299 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 300 int flags); 301 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr, 302 size_t numblks, int flags, struct xfs_buf **bpp, 303 const struct xfs_buf_ops *ops); 304 void xfs_buf_hold(struct xfs_buf *bp); 305 306 /* Releasing Buffers */ 307 extern void xfs_buf_free(xfs_buf_t *); 308 extern void xfs_buf_rele(xfs_buf_t *); 309 310 /* Locking and Unlocking Buffers */ 311 extern int xfs_buf_trylock(xfs_buf_t *); 312 extern void xfs_buf_lock(xfs_buf_t *); 313 extern void xfs_buf_unlock(xfs_buf_t *); 314 #define xfs_buf_islocked(bp) \ 315 ((bp)->b_sema.count <= 0) 316 317 /* Buffer Read and Write Routines */ 318 extern int xfs_bwrite(struct xfs_buf *bp); 319 extern void xfs_buf_ioend(struct xfs_buf *bp); 320 extern void xfs_buf_ioerror(xfs_buf_t *, int); 321 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 322 extern void xfs_buf_submit(struct xfs_buf *bp); 323 extern int xfs_buf_submit_wait(struct xfs_buf *bp); 324 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 325 xfs_buf_rw_t); 326 #define xfs_buf_zero(bp, off, len) \ 327 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 328 329 /* Buffer Utility Routines */ 330 extern void *xfs_buf_offset(struct xfs_buf *, size_t); 331 extern void xfs_buf_stale(struct xfs_buf *bp); 332 333 /* Delayed Write Buffer Routines */ 334 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 335 extern int xfs_buf_delwri_submit(struct list_head *); 336 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 337 338 /* Buffer Daemon Setup Routines */ 339 extern int xfs_buf_init(void); 340 extern void xfs_buf_terminate(void); 341 342 /* 343 * These macros use the IO block map rather than b_bn. b_bn is now really 344 * just for the buffer cache index for cached buffers. As IO does not use b_bn 345 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 346 * map directly. Uncached buffers are not allowed to be discontiguous, so this 347 * is safe to do. 348 * 349 * In future, uncached buffers will pass the block number directly to the io 350 * request function and hence these macros will go away at that point. 351 */ 352 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) 353 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno)) 354 355 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 356 { 357 atomic_set(&bp->b_lru_ref, lru_ref); 358 } 359 360 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 361 { 362 return atomic_read(&bp->b_pin_count); 363 } 364 365 static inline void xfs_buf_relse(xfs_buf_t *bp) 366 { 367 xfs_buf_unlock(bp); 368 xfs_buf_rele(bp); 369 } 370 371 static inline int 372 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 373 { 374 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), 375 cksum_offset); 376 } 377 378 static inline void 379 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 380 { 381 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), 382 cksum_offset); 383 } 384 385 /* 386 * Handling of buftargs. 387 */ 388 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 389 struct block_device *); 390 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 391 extern void xfs_wait_buftarg(xfs_buftarg_t *); 392 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); 393 394 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 395 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 396 397 #endif /* __XFS_BUF_H__ */ 398