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/buffer_head.h> 27 #include <linux/uio.h> 28 29 /* 30 * Base types 31 */ 32 33 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL)) 34 35 #define xfs_buf_ctob(pp) ((pp) * PAGE_CACHE_SIZE) 36 #define xfs_buf_btoc(dd) (((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT) 37 #define xfs_buf_btoct(dd) ((dd) >> PAGE_CACHE_SHIFT) 38 #define xfs_buf_poff(aa) ((aa) & ~PAGE_CACHE_MASK) 39 40 typedef enum { 41 XBRW_READ = 1, /* transfer into target memory */ 42 XBRW_WRITE = 2, /* transfer from target memory */ 43 XBRW_ZERO = 3, /* Zero target memory */ 44 } xfs_buf_rw_t; 45 46 #define XBF_READ (1 << 0) /* buffer intended for reading from device */ 47 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */ 48 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */ 49 #define XBF_MAPPED (1 << 3) /* buffer mapped (b_addr valid) */ 50 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */ 51 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */ 52 #define XBF_DELWRI (1 << 6) /* buffer has dirty pages */ 53 #define XBF_STALE (1 << 7) /* buffer has been staled, do not find it */ 54 55 /* I/O hints for the BIO layer */ 56 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */ 57 #define XBF_FUA (1 << 11)/* force cache write through mode */ 58 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */ 59 60 /* flags used only as arguments to access routines */ 61 #define XBF_LOCK (1 << 15)/* lock requested */ 62 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */ 63 #define XBF_DONT_BLOCK (1 << 17)/* do not block in current thread */ 64 65 /* flags used only internally */ 66 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */ 67 #define _XBF_KMEM (1 << 21)/* backed by heap memory */ 68 #define _XBF_DELWRI_Q (1 << 22)/* buffer on delwri queue */ 69 70 typedef unsigned int xfs_buf_flags_t; 71 72 #define XFS_BUF_FLAGS \ 73 { XBF_READ, "READ" }, \ 74 { XBF_WRITE, "WRITE" }, \ 75 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 76 { XBF_MAPPED, "MAPPED" }, \ 77 { XBF_ASYNC, "ASYNC" }, \ 78 { XBF_DONE, "DONE" }, \ 79 { XBF_DELWRI, "DELWRI" }, \ 80 { XBF_STALE, "STALE" }, \ 81 { XBF_SYNCIO, "SYNCIO" }, \ 82 { XBF_FUA, "FUA" }, \ 83 { XBF_FLUSH, "FLUSH" }, \ 84 { XBF_LOCK, "LOCK" }, /* should never be set */\ 85 { XBF_TRYLOCK, "TRYLOCK" }, /* ditto */\ 86 { XBF_DONT_BLOCK, "DONT_BLOCK" }, /* ditto */\ 87 { _XBF_PAGES, "PAGES" }, \ 88 { _XBF_KMEM, "KMEM" }, \ 89 { _XBF_DELWRI_Q, "DELWRI_Q" } 90 91 typedef enum { 92 XBT_FORCE_FLUSH = 0, 93 } xfs_buftarg_flags_t; 94 95 typedef struct xfs_buftarg { 96 dev_t bt_dev; 97 struct block_device *bt_bdev; 98 struct backing_dev_info *bt_bdi; 99 struct xfs_mount *bt_mount; 100 unsigned int bt_bsize; 101 unsigned int bt_sshift; 102 size_t bt_smask; 103 104 /* per device delwri queue */ 105 struct task_struct *bt_task; 106 struct list_head bt_delwri_queue; 107 spinlock_t bt_delwri_lock; 108 unsigned long bt_flags; 109 110 /* LRU control structures */ 111 struct shrinker bt_shrinker; 112 struct list_head bt_lru; 113 spinlock_t bt_lru_lock; 114 unsigned int bt_lru_nr; 115 } xfs_buftarg_t; 116 117 struct xfs_buf; 118 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 119 120 #define XB_PAGES 2 121 122 typedef struct xfs_buf { 123 /* 124 * first cacheline holds all the fields needed for an uncontended cache 125 * hit to be fully processed. The semaphore straddles the cacheline 126 * boundary, but the counter and lock sits on the first cacheline, 127 * which is the only bit that is touched if we hit the semaphore 128 * fast-path on locking. 129 */ 130 struct rb_node b_rbnode; /* rbtree node */ 131 xfs_off_t b_file_offset; /* offset in file */ 132 size_t b_buffer_length;/* size of buffer in bytes */ 133 atomic_t b_hold; /* reference count */ 134 atomic_t b_lru_ref; /* lru reclaim ref count */ 135 xfs_buf_flags_t b_flags; /* status flags */ 136 struct semaphore b_sema; /* semaphore for lockables */ 137 138 struct list_head b_lru; /* lru list */ 139 wait_queue_head_t b_waiters; /* unpin waiters */ 140 struct list_head b_list; 141 struct xfs_perag *b_pag; /* contains rbtree root */ 142 xfs_buftarg_t *b_target; /* buffer target (device) */ 143 xfs_daddr_t b_bn; /* block number for I/O */ 144 size_t b_count_desired;/* desired transfer size */ 145 void *b_addr; /* virtual address of buffer */ 146 struct work_struct b_iodone_work; 147 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 148 struct completion b_iowait; /* queue for I/O waiters */ 149 void *b_fspriv; 150 struct xfs_trans *b_transp; 151 struct page **b_pages; /* array of page pointers */ 152 struct page *b_page_array[XB_PAGES]; /* inline pages */ 153 unsigned long b_queuetime; /* time buffer was queued */ 154 atomic_t b_pin_count; /* pin count */ 155 atomic_t b_io_remaining; /* #outstanding I/O requests */ 156 unsigned int b_page_count; /* size of page array */ 157 unsigned int b_offset; /* page offset in first page */ 158 unsigned short b_error; /* error code on I/O */ 159 #ifdef XFS_BUF_LOCK_TRACKING 160 int b_last_holder; 161 #endif 162 } xfs_buf_t; 163 164 165 /* Finding and Reading Buffers */ 166 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t, 167 xfs_buf_flags_t, xfs_buf_t *); 168 #define xfs_incore(buftarg,blkno,len,lockit) \ 169 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL) 170 171 extern xfs_buf_t *xfs_buf_get(xfs_buftarg_t *, xfs_off_t, size_t, 172 xfs_buf_flags_t); 173 extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t, 174 xfs_buf_flags_t); 175 176 struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *, xfs_off_t, size_t, 177 xfs_buf_flags_t); 178 extern void xfs_buf_set_empty(struct xfs_buf *bp, size_t len); 179 extern xfs_buf_t *xfs_buf_get_uncached(struct xfs_buftarg *, size_t, int); 180 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t); 181 extern void xfs_buf_hold(xfs_buf_t *); 182 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t); 183 struct xfs_buf *xfs_buf_read_uncached(struct xfs_mount *mp, 184 struct xfs_buftarg *target, 185 xfs_daddr_t daddr, size_t length, int flags); 186 187 /* Releasing Buffers */ 188 extern void xfs_buf_free(xfs_buf_t *); 189 extern void xfs_buf_rele(xfs_buf_t *); 190 191 /* Locking and Unlocking Buffers */ 192 extern int xfs_buf_trylock(xfs_buf_t *); 193 extern void xfs_buf_lock(xfs_buf_t *); 194 extern void xfs_buf_unlock(xfs_buf_t *); 195 #define xfs_buf_islocked(bp) \ 196 ((bp)->b_sema.count <= 0) 197 198 /* Buffer Read and Write Routines */ 199 extern int xfs_bwrite(struct xfs_buf *bp); 200 201 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *); 202 extern int xfs_bdstrat_cb(struct xfs_buf *); 203 204 extern void xfs_buf_ioend(xfs_buf_t *, int); 205 extern void xfs_buf_ioerror(xfs_buf_t *, int); 206 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 207 extern int xfs_buf_iorequest(xfs_buf_t *); 208 extern int xfs_buf_iowait(xfs_buf_t *); 209 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 210 xfs_buf_rw_t); 211 #define xfs_buf_zero(bp, off, len) \ 212 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 213 214 static inline int xfs_buf_geterror(xfs_buf_t *bp) 215 { 216 return bp ? bp->b_error : ENOMEM; 217 } 218 219 /* Buffer Utility Routines */ 220 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t); 221 222 /* Delayed Write Buffer Routines */ 223 extern void xfs_buf_delwri_queue(struct xfs_buf *); 224 extern void xfs_buf_delwri_dequeue(struct xfs_buf *); 225 extern void xfs_buf_delwri_promote(struct xfs_buf *); 226 227 /* Buffer Daemon Setup Routines */ 228 extern int xfs_buf_init(void); 229 extern void xfs_buf_terminate(void); 230 231 #define XFS_BUF_ZEROFLAGS(bp) \ 232 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI| \ 233 XBF_SYNCIO|XBF_FUA|XBF_FLUSH)) 234 235 void xfs_buf_stale(struct xfs_buf *bp); 236 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) 237 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) 238 239 #define XFS_BUF_ISDELAYWRITE(bp) ((bp)->b_flags & XBF_DELWRI) 240 241 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) 242 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) 243 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) 244 245 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) 246 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) 247 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) 248 249 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) 250 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) 251 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) 252 253 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) 254 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) 255 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) 256 257 #define XFS_BUF_ADDR(bp) ((bp)->b_bn) 258 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno)) 259 #define XFS_BUF_OFFSET(bp) ((bp)->b_file_offset) 260 #define XFS_BUF_SET_OFFSET(bp, off) ((bp)->b_file_offset = (off)) 261 #define XFS_BUF_COUNT(bp) ((bp)->b_count_desired) 262 #define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt)) 263 #define XFS_BUF_SIZE(bp) ((bp)->b_buffer_length) 264 #define XFS_BUF_SET_SIZE(bp, cnt) ((bp)->b_buffer_length = (cnt)) 265 266 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 267 { 268 atomic_set(&bp->b_lru_ref, lru_ref); 269 } 270 271 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 272 { 273 return atomic_read(&bp->b_pin_count); 274 } 275 276 static inline void xfs_buf_relse(xfs_buf_t *bp) 277 { 278 xfs_buf_unlock(bp); 279 xfs_buf_rele(bp); 280 } 281 282 /* 283 * Handling of buftargs. 284 */ 285 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 286 struct block_device *, int, const char *); 287 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 288 extern void xfs_wait_buftarg(xfs_buftarg_t *); 289 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int); 290 extern int xfs_flush_buftarg(xfs_buftarg_t *, int); 291 292 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 293 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 294 295 #endif /* __XFS_BUF_H__ */ 296