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 67 typedef unsigned int xfs_buf_flags_t; 68 69 #define XFS_BUF_FLAGS \ 70 { XBF_READ, "READ" }, \ 71 { XBF_WRITE, "WRITE" }, \ 72 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 73 { XBF_NO_IOACCT, "NO_IOACCT" }, \ 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 88 89 /* 90 * Internal state flags. 91 */ 92 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */ 93 #define XFS_BSTATE_IN_FLIGHT (1 << 1) /* I/O in flight */ 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 xfs_mount *bt_mount; 112 unsigned int bt_meta_sectorsize; 113 size_t bt_meta_sectormask; 114 size_t bt_logical_sectorsize; 115 size_t bt_logical_sectormask; 116 117 /* LRU control structures */ 118 struct shrinker bt_shrinker; 119 struct list_lru bt_lru; 120 121 struct percpu_counter bt_io_count; 122 } xfs_buftarg_t; 123 124 struct xfs_buf; 125 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 126 127 128 #define XB_PAGES 2 129 130 struct xfs_buf_map { 131 xfs_daddr_t bm_bn; /* block number for I/O */ 132 int bm_len; /* size of I/O */ 133 }; 134 135 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \ 136 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) }; 137 138 struct xfs_buf_ops { 139 char *name; 140 void (*verify_read)(struct xfs_buf *); 141 void (*verify_write)(struct xfs_buf *); 142 }; 143 144 typedef struct xfs_buf { 145 /* 146 * first cacheline holds all the fields needed for an uncontended cache 147 * hit to be fully processed. The semaphore straddles the cacheline 148 * boundary, but the counter and lock sits on the first cacheline, 149 * which is the only bit that is touched if we hit the semaphore 150 * fast-path on locking. 151 */ 152 struct rhash_head b_rhash_head; /* pag buffer hash node */ 153 xfs_daddr_t b_bn; /* block number of buffer */ 154 int b_length; /* size of buffer in BBs */ 155 atomic_t b_hold; /* reference count */ 156 atomic_t b_lru_ref; /* lru reclaim ref count */ 157 xfs_buf_flags_t b_flags; /* status flags */ 158 struct semaphore b_sema; /* semaphore for lockables */ 159 160 /* 161 * concurrent access to b_lru and b_lru_flags are protected by 162 * bt_lru_lock and not by b_sema 163 */ 164 struct list_head b_lru; /* lru list */ 165 spinlock_t b_lock; /* internal state lock */ 166 unsigned int b_state; /* internal state flags */ 167 int b_io_error; /* internal IO error state */ 168 wait_queue_head_t b_waiters; /* unpin waiters */ 169 struct list_head b_list; 170 struct xfs_perag *b_pag; /* contains rbtree root */ 171 xfs_buftarg_t *b_target; /* buffer target (device) */ 172 void *b_addr; /* virtual address of buffer */ 173 struct work_struct b_ioend_work; 174 struct workqueue_struct *b_ioend_wq; /* I/O completion wq */ 175 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 176 struct completion b_iowait; /* queue for I/O waiters */ 177 void *b_fspriv; 178 struct xfs_trans *b_transp; 179 struct page **b_pages; /* array of page pointers */ 180 struct page *b_page_array[XB_PAGES]; /* inline pages */ 181 struct xfs_buf_map *b_maps; /* compound buffer map */ 182 struct xfs_buf_map __b_map; /* inline compound buffer map */ 183 int b_map_count; 184 int b_io_length; /* IO size in BBs */ 185 atomic_t b_pin_count; /* pin count */ 186 atomic_t b_io_remaining; /* #outstanding I/O requests */ 187 unsigned int b_page_count; /* size of page array */ 188 unsigned int b_offset; /* page offset in first page */ 189 int b_error; /* error code on I/O */ 190 191 /* 192 * async write failure retry count. Initialised to zero on the first 193 * failure, then when it exceeds the maximum configured without a 194 * success the write is considered to be failed permanently and the 195 * iodone handler will take appropriate action. 196 * 197 * For retry timeouts, we record the jiffie of the first failure. This 198 * means that we can change the retry timeout for buffers already under 199 * I/O and thus avoid getting stuck in a retry loop with a long timeout. 200 * 201 * last_error is used to ensure that we are getting repeated errors, not 202 * different errors. e.g. a block device might change ENOSPC to EIO when 203 * a failure timeout occurs, so we want to re-initialise the error 204 * retry behaviour appropriately when that happens. 205 */ 206 int b_retries; 207 unsigned long b_first_retry_time; /* in jiffies */ 208 int b_last_error; 209 210 const struct xfs_buf_ops *b_ops; 211 212 #ifdef XFS_BUF_LOCK_TRACKING 213 int b_last_holder; 214 #endif 215 } xfs_buf_t; 216 217 /* Finding and Reading Buffers */ 218 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, 219 struct xfs_buf_map *map, int nmaps, 220 xfs_buf_flags_t flags, struct xfs_buf *new_bp); 221 222 static inline struct xfs_buf * 223 xfs_incore( 224 struct xfs_buftarg *target, 225 xfs_daddr_t blkno, 226 size_t numblks, 227 xfs_buf_flags_t flags) 228 { 229 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 230 return _xfs_buf_find(target, &map, 1, flags, NULL); 231 } 232 233 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 234 struct xfs_buf_map *map, int nmaps, 235 xfs_buf_flags_t flags); 236 237 static inline struct xfs_buf * 238 xfs_buf_alloc( 239 struct xfs_buftarg *target, 240 xfs_daddr_t blkno, 241 size_t numblks, 242 xfs_buf_flags_t flags) 243 { 244 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 245 return _xfs_buf_alloc(target, &map, 1, flags); 246 } 247 248 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 249 struct xfs_buf_map *map, int nmaps, 250 xfs_buf_flags_t flags); 251 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 252 struct xfs_buf_map *map, int nmaps, 253 xfs_buf_flags_t flags, 254 const struct xfs_buf_ops *ops); 255 void xfs_buf_readahead_map(struct xfs_buftarg *target, 256 struct xfs_buf_map *map, int nmaps, 257 const struct xfs_buf_ops *ops); 258 259 static inline struct xfs_buf * 260 xfs_buf_get( 261 struct xfs_buftarg *target, 262 xfs_daddr_t blkno, 263 size_t numblks, 264 xfs_buf_flags_t flags) 265 { 266 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 267 return xfs_buf_get_map(target, &map, 1, flags); 268 } 269 270 static inline struct xfs_buf * 271 xfs_buf_read( 272 struct xfs_buftarg *target, 273 xfs_daddr_t blkno, 274 size_t numblks, 275 xfs_buf_flags_t flags, 276 const struct xfs_buf_ops *ops) 277 { 278 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 279 return xfs_buf_read_map(target, &map, 1, flags, ops); 280 } 281 282 static inline void 283 xfs_buf_readahead( 284 struct xfs_buftarg *target, 285 xfs_daddr_t blkno, 286 size_t numblks, 287 const struct xfs_buf_ops *ops) 288 { 289 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 290 return xfs_buf_readahead_map(target, &map, 1, ops); 291 } 292 293 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 294 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 295 296 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 297 int flags); 298 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr, 299 size_t numblks, int flags, struct xfs_buf **bpp, 300 const struct xfs_buf_ops *ops); 301 void xfs_buf_hold(struct xfs_buf *bp); 302 303 /* Releasing Buffers */ 304 extern void xfs_buf_free(xfs_buf_t *); 305 extern void xfs_buf_rele(xfs_buf_t *); 306 307 /* Locking and Unlocking Buffers */ 308 extern int xfs_buf_trylock(xfs_buf_t *); 309 extern void xfs_buf_lock(xfs_buf_t *); 310 extern void xfs_buf_unlock(xfs_buf_t *); 311 #define xfs_buf_islocked(bp) \ 312 ((bp)->b_sema.count <= 0) 313 314 /* Buffer Read and Write Routines */ 315 extern int xfs_bwrite(struct xfs_buf *bp); 316 extern void xfs_buf_ioend(struct xfs_buf *bp); 317 extern void xfs_buf_ioerror(xfs_buf_t *, int); 318 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 319 extern void xfs_buf_submit(struct xfs_buf *bp); 320 extern int xfs_buf_submit_wait(struct xfs_buf *bp); 321 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 322 xfs_buf_rw_t); 323 #define xfs_buf_zero(bp, off, len) \ 324 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 325 326 /* Buffer Utility Routines */ 327 extern void *xfs_buf_offset(struct xfs_buf *, size_t); 328 extern void xfs_buf_stale(struct xfs_buf *bp); 329 330 /* Delayed Write Buffer Routines */ 331 extern void xfs_buf_delwri_cancel(struct list_head *); 332 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 333 extern int xfs_buf_delwri_submit(struct list_head *); 334 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 335 336 /* Buffer Daemon Setup Routines */ 337 extern int xfs_buf_init(void); 338 extern void xfs_buf_terminate(void); 339 340 /* 341 * These macros use the IO block map rather than b_bn. b_bn is now really 342 * just for the buffer cache index for cached buffers. As IO does not use b_bn 343 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 344 * map directly. Uncached buffers are not allowed to be discontiguous, so this 345 * is safe to do. 346 * 347 * In future, uncached buffers will pass the block number directly to the io 348 * request function and hence these macros will go away at that point. 349 */ 350 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) 351 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno)) 352 353 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 354 { 355 atomic_set(&bp->b_lru_ref, lru_ref); 356 } 357 358 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 359 { 360 return atomic_read(&bp->b_pin_count); 361 } 362 363 static inline void xfs_buf_relse(xfs_buf_t *bp) 364 { 365 xfs_buf_unlock(bp); 366 xfs_buf_rele(bp); 367 } 368 369 static inline int 370 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 371 { 372 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), 373 cksum_offset); 374 } 375 376 static inline void 377 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 378 { 379 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), 380 cksum_offset); 381 } 382 383 /* 384 * Handling of buftargs. 385 */ 386 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 387 struct block_device *); 388 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 389 extern void xfs_wait_buftarg(xfs_buftarg_t *); 390 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); 391 392 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 393 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 394 395 #endif /* __XFS_BUF_H__ */ 396