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