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 void (*verify_read)(struct xfs_buf *); 136 void (*verify_write)(struct xfs_buf *); 137 }; 138 139 typedef struct xfs_buf { 140 /* 141 * first cacheline holds all the fields needed for an uncontended cache 142 * hit to be fully processed. The semaphore straddles the cacheline 143 * boundary, but the counter and lock sits on the first cacheline, 144 * which is the only bit that is touched if we hit the semaphore 145 * fast-path on locking. 146 */ 147 struct rb_node b_rbnode; /* rbtree node */ 148 xfs_daddr_t b_bn; /* block number of buffer */ 149 int b_length; /* size of buffer in BBs */ 150 atomic_t b_hold; /* reference count */ 151 atomic_t b_lru_ref; /* lru reclaim ref count */ 152 xfs_buf_flags_t b_flags; /* status flags */ 153 struct semaphore b_sema; /* semaphore for lockables */ 154 155 /* 156 * concurrent access to b_lru and b_lru_flags are protected by 157 * bt_lru_lock and not by b_sema 158 */ 159 struct list_head b_lru; /* lru list */ 160 spinlock_t b_lock; /* internal state lock */ 161 unsigned int b_state; /* internal state flags */ 162 int b_io_error; /* internal IO error state */ 163 wait_queue_head_t b_waiters; /* unpin waiters */ 164 struct list_head b_list; 165 struct xfs_perag *b_pag; /* contains rbtree root */ 166 xfs_buftarg_t *b_target; /* buffer target (device) */ 167 void *b_addr; /* virtual address of buffer */ 168 struct work_struct b_ioend_work; 169 struct workqueue_struct *b_ioend_wq; /* I/O completion wq */ 170 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 171 struct completion b_iowait; /* queue for I/O waiters */ 172 void *b_fspriv; 173 struct xfs_trans *b_transp; 174 struct page **b_pages; /* array of page pointers */ 175 struct page *b_page_array[XB_PAGES]; /* inline pages */ 176 struct xfs_buf_map *b_maps; /* compound buffer map */ 177 struct xfs_buf_map __b_map; /* inline compound buffer map */ 178 int b_map_count; 179 int b_io_length; /* IO size in BBs */ 180 atomic_t b_pin_count; /* pin count */ 181 atomic_t b_io_remaining; /* #outstanding I/O requests */ 182 unsigned int b_page_count; /* size of page array */ 183 unsigned int b_offset; /* page offset in first page */ 184 int b_error; /* error code on I/O */ 185 const struct xfs_buf_ops *b_ops; 186 187 #ifdef XFS_BUF_LOCK_TRACKING 188 int b_last_holder; 189 #endif 190 } xfs_buf_t; 191 192 /* Finding and Reading Buffers */ 193 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, 194 struct xfs_buf_map *map, int nmaps, 195 xfs_buf_flags_t flags, struct xfs_buf *new_bp); 196 197 static inline struct xfs_buf * 198 xfs_incore( 199 struct xfs_buftarg *target, 200 xfs_daddr_t blkno, 201 size_t numblks, 202 xfs_buf_flags_t flags) 203 { 204 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 205 return _xfs_buf_find(target, &map, 1, flags, NULL); 206 } 207 208 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, 209 struct xfs_buf_map *map, int nmaps, 210 xfs_buf_flags_t flags); 211 212 static inline struct xfs_buf * 213 xfs_buf_alloc( 214 struct xfs_buftarg *target, 215 xfs_daddr_t blkno, 216 size_t numblks, 217 xfs_buf_flags_t flags) 218 { 219 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 220 return _xfs_buf_alloc(target, &map, 1, flags); 221 } 222 223 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, 224 struct xfs_buf_map *map, int nmaps, 225 xfs_buf_flags_t flags); 226 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, 227 struct xfs_buf_map *map, int nmaps, 228 xfs_buf_flags_t flags, 229 const struct xfs_buf_ops *ops); 230 void xfs_buf_readahead_map(struct xfs_buftarg *target, 231 struct xfs_buf_map *map, int nmaps, 232 const struct xfs_buf_ops *ops); 233 234 static inline struct xfs_buf * 235 xfs_buf_get( 236 struct xfs_buftarg *target, 237 xfs_daddr_t blkno, 238 size_t numblks, 239 xfs_buf_flags_t flags) 240 { 241 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 242 return xfs_buf_get_map(target, &map, 1, flags); 243 } 244 245 static inline struct xfs_buf * 246 xfs_buf_read( 247 struct xfs_buftarg *target, 248 xfs_daddr_t blkno, 249 size_t numblks, 250 xfs_buf_flags_t flags, 251 const struct xfs_buf_ops *ops) 252 { 253 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 254 return xfs_buf_read_map(target, &map, 1, flags, ops); 255 } 256 257 static inline void 258 xfs_buf_readahead( 259 struct xfs_buftarg *target, 260 xfs_daddr_t blkno, 261 size_t numblks, 262 const struct xfs_buf_ops *ops) 263 { 264 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); 265 return xfs_buf_readahead_map(target, &map, 1, ops); 266 } 267 268 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); 269 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); 270 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); 271 272 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, 273 int flags); 274 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr, 275 size_t numblks, int flags, struct xfs_buf **bpp, 276 const struct xfs_buf_ops *ops); 277 void xfs_buf_hold(struct xfs_buf *bp); 278 279 /* Releasing Buffers */ 280 extern void xfs_buf_free(xfs_buf_t *); 281 extern void xfs_buf_rele(xfs_buf_t *); 282 283 /* Locking and Unlocking Buffers */ 284 extern int xfs_buf_trylock(xfs_buf_t *); 285 extern void xfs_buf_lock(xfs_buf_t *); 286 extern void xfs_buf_unlock(xfs_buf_t *); 287 #define xfs_buf_islocked(bp) \ 288 ((bp)->b_sema.count <= 0) 289 290 /* Buffer Read and Write Routines */ 291 extern int xfs_bwrite(struct xfs_buf *bp); 292 extern void xfs_buf_ioend(struct xfs_buf *bp); 293 extern void xfs_buf_ioerror(xfs_buf_t *, int); 294 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 295 extern void xfs_buf_submit(struct xfs_buf *bp); 296 extern int xfs_buf_submit_wait(struct xfs_buf *bp); 297 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 298 xfs_buf_rw_t); 299 #define xfs_buf_zero(bp, off, len) \ 300 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 301 302 /* Buffer Utility Routines */ 303 extern void *xfs_buf_offset(struct xfs_buf *, size_t); 304 305 /* Delayed Write Buffer Routines */ 306 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); 307 extern int xfs_buf_delwri_submit(struct list_head *); 308 extern int xfs_buf_delwri_submit_nowait(struct list_head *); 309 310 /* Buffer Daemon Setup Routines */ 311 extern int xfs_buf_init(void); 312 extern void xfs_buf_terminate(void); 313 314 #define XFS_BUF_ZEROFLAGS(bp) \ 315 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \ 316 XBF_SYNCIO|XBF_FUA|XBF_FLUSH| \ 317 XBF_WRITE_FAIL)) 318 319 void xfs_buf_stale(struct xfs_buf *bp); 320 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) 321 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) 322 323 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) 324 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) 325 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) 326 327 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) 328 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) 329 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) 330 331 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) 332 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) 333 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) 334 335 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) 336 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) 337 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) 338 339 /* 340 * These macros use the IO block map rather than b_bn. b_bn is now really 341 * just for the buffer cache index for cached buffers. As IO does not use b_bn 342 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO 343 * map directly. Uncached buffers are not allowed to be discontiguous, so this 344 * is safe to do. 345 * 346 * In future, uncached buffers will pass the block number directly to the io 347 * request function and hence these macros will go away at that point. 348 */ 349 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) 350 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno)) 351 352 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 353 { 354 atomic_set(&bp->b_lru_ref, lru_ref); 355 } 356 357 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 358 { 359 return atomic_read(&bp->b_pin_count); 360 } 361 362 static inline void xfs_buf_relse(xfs_buf_t *bp) 363 { 364 xfs_buf_unlock(bp); 365 xfs_buf_rele(bp); 366 } 367 368 static inline int 369 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 370 { 371 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), 372 cksum_offset); 373 } 374 375 static inline void 376 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset) 377 { 378 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), 379 cksum_offset); 380 } 381 382 /* 383 * Handling of buftargs. 384 */ 385 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 386 struct block_device *); 387 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 388 extern void xfs_wait_buftarg(xfs_buftarg_t *); 389 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); 390 391 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 392 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 393 394 #endif /* __XFS_BUF_H__ */ 395