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 dax_device *bt_daxdev; 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 xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp); 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_log_item; 180 struct list_head b_li_list; /* Log items list head */ 181 struct xfs_trans *b_transp; 182 struct page **b_pages; /* array of page pointers */ 183 struct page *b_page_array[XB_PAGES]; /* inline pages */ 184 struct xfs_buf_map *b_maps; /* compound buffer map */ 185 struct xfs_buf_map __b_map; /* inline compound buffer map */ 186 int b_map_count; 187 int b_io_length; /* IO size in BBs */ 188 atomic_t b_pin_count; /* pin count */ 189 atomic_t b_io_remaining; /* #outstanding I/O requests */ 190 unsigned int b_page_count; /* size of page array */ 191 unsigned int b_offset; /* page offset in first page */ 192 int b_error; /* error code on I/O */ 193 194 /* 195 * async write failure retry count. Initialised to zero on the first 196 * failure, then when it exceeds the maximum configured without a 197 * success the write is considered to be failed permanently and the 198 * iodone handler will take appropriate action. 199 * 200 * For retry timeouts, we record the jiffie of the first failure. This 201 * means that we can change the retry timeout for buffers already under 202 * I/O and thus avoid getting stuck in a retry loop with a long timeout. 203 * 204 * last_error is used to ensure that we are getting repeated errors, not 205 * different errors. e.g. a block device might change ENOSPC to EIO when 206 * a failure timeout occurs, so we want to re-initialise the error 207 * retry behaviour appropriately when that happens. 208 */ 209 int b_retries; 210 unsigned long b_first_retry_time; /* in jiffies */ 211 int b_last_error; 212 213 const struct xfs_buf_ops *b_ops; 214 215 #ifdef XFS_BUF_LOCK_TRACKING 216 int b_last_holder; 217 #endif 218 } xfs_buf_t; 219 220 /* Finding and Reading Buffers */ 221 struct xfs_buf *xfs_buf_incore(struct xfs_buftarg *target, 222 xfs_daddr_t blkno, size_t numblks, 223 xfs_buf_flags_t flags); 224 225 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 226 struct xfs_buf_map *map, int nmaps, 227 xfs_buf_flags_t flags); 228 229 static inline struct xfs_buf * 230 xfs_buf_alloc( 231 struct xfs_buftarg *target, 232 xfs_daddr_t blkno, 233 size_t numblks, 234 xfs_buf_flags_t flags) 235 { 236 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 237 return _xfs_buf_alloc(target, &map, 1, flags); 238 } 239 240 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 241 struct xfs_buf_map *map, int nmaps, 242 xfs_buf_flags_t flags); 243 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 244 struct xfs_buf_map *map, int nmaps, 245 xfs_buf_flags_t flags, 246 const struct xfs_buf_ops *ops); 247 void xfs_buf_readahead_map(struct xfs_buftarg *target, 248 struct xfs_buf_map *map, int nmaps, 249 const struct xfs_buf_ops *ops); 250 251 static inline struct xfs_buf * 252 xfs_buf_get( 253 struct xfs_buftarg *target, 254 xfs_daddr_t blkno, 255 size_t numblks, 256 xfs_buf_flags_t flags) 257 { 258 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 259 return xfs_buf_get_map(target, &map, 1, flags); 260 } 261 262 static inline struct xfs_buf * 263 xfs_buf_read( 264 struct xfs_buftarg *target, 265 xfs_daddr_t blkno, 266 size_t numblks, 267 xfs_buf_flags_t flags, 268 const struct xfs_buf_ops *ops) 269 { 270 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 271 return xfs_buf_read_map(target, &map, 1, flags, ops); 272 } 273 274 static inline void 275 xfs_buf_readahead( 276 struct xfs_buftarg *target, 277 xfs_daddr_t blkno, 278 size_t numblks, 279 const struct xfs_buf_ops *ops) 280 { 281 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 282 return xfs_buf_readahead_map(target, &map, 1, ops); 283 } 284 285 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 286 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 287 288 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 289 int flags); 290 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr, 291 size_t numblks, int flags, struct xfs_buf **bpp, 292 const struct xfs_buf_ops *ops); 293 void xfs_buf_hold(struct xfs_buf *bp); 294 295 /* Releasing Buffers */ 296 extern void xfs_buf_free(xfs_buf_t *); 297 extern void xfs_buf_rele(xfs_buf_t *); 298 299 /* Locking and Unlocking Buffers */ 300 extern int xfs_buf_trylock(xfs_buf_t *); 301 extern void xfs_buf_lock(xfs_buf_t *); 302 extern void xfs_buf_unlock(xfs_buf_t *); 303 #define xfs_buf_islocked(bp) \ 304 ((bp)->b_sema.count <= 0) 305 306 /* Buffer Read and Write Routines */ 307 extern int xfs_bwrite(struct xfs_buf *bp); 308 extern void xfs_buf_ioend(struct xfs_buf *bp); 309 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error, 310 xfs_failaddr_t failaddr); 311 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address) 312 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 313 extern void xfs_buf_submit(struct xfs_buf *bp); 314 extern int xfs_buf_submit_wait(struct xfs_buf *bp); 315 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 316 xfs_buf_rw_t); 317 #define xfs_buf_zero(bp, off, len) \ 318 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 319 320 /* Buffer Utility Routines */ 321 extern void *xfs_buf_offset(struct xfs_buf *, size_t); 322 extern void xfs_buf_stale(struct xfs_buf *bp); 323 324 /* Delayed Write Buffer Routines */ 325 extern void xfs_buf_delwri_cancel(struct list_head *); 326 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 327 extern int xfs_buf_delwri_submit(struct list_head *); 328 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 329 extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *); 330 331 /* Buffer Daemon Setup Routines */ 332 extern int xfs_buf_init(void); 333 extern void xfs_buf_terminate(void); 334 335 /* 336 * These macros use the IO block map rather than b_bn. b_bn is now really 337 * just for the buffer cache index for cached buffers. As IO does not use b_bn 338 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 339 * map directly. Uncached buffers are not allowed to be discontiguous, so this 340 * is safe to do. 341 * 342 * In future, uncached buffers will pass the block number directly to the io 343 * request function and hence these macros will go away at that point. 344 */ 345 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) 346 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno)) 347 348 void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref); 349 350 /* 351 * If the buffer is already on the LRU, do nothing. Otherwise set the buffer 352 * up with a reference count of 0 so it will be tossed from the cache when 353 * released. 354 */ 355 static inline void xfs_buf_oneshot(struct xfs_buf *bp) 356 { 357 if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1) 358 return; 359 atomic_set(&bp->b_lru_ref, 0); 360 } 361 362 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 363 { 364 return atomic_read(&bp->b_pin_count); 365 } 366 367 static inline void xfs_buf_relse(xfs_buf_t *bp) 368 { 369 xfs_buf_unlock(bp); 370 xfs_buf_rele(bp); 371 } 372 373 static inline int 374 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 375 { 376 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), 377 cksum_offset); 378 } 379 380 static inline void 381 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 382 { 383 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), 384 cksum_offset); 385 } 386 387 /* 388 * Handling of buftargs. 389 */ 390 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 391 struct block_device *, struct dax_device *); 392 extern void xfs_free_buftarg(struct xfs_buftarg *); 393 extern void xfs_wait_buftarg(xfs_buftarg_t *); 394 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); 395 396 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 397 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 398 399 #endif /* __XFS_BUF_H__ */ 400