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 <asm/system.h> 25 #include <linux/mm.h> 26 #include <linux/fs.h> 27 #include <linux/buffer_head.h> 28 #include <linux/uio.h> 29 30 /* 31 * Base types 32 */ 33 34 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL)) 35 36 #define xfs_buf_ctob(pp) ((pp) * PAGE_CACHE_SIZE) 37 #define xfs_buf_btoc(dd) (((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT) 38 #define xfs_buf_btoct(dd) ((dd) >> PAGE_CACHE_SHIFT) 39 #define xfs_buf_poff(aa) ((aa) & ~PAGE_CACHE_MASK) 40 41 typedef enum { 42 XBRW_READ = 1, /* transfer into target memory */ 43 XBRW_WRITE = 2, /* transfer from target memory */ 44 XBRW_ZERO = 3, /* Zero target memory */ 45 } xfs_buf_rw_t; 46 47 #define XBF_READ (1 << 0) /* buffer intended for reading from device */ 48 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */ 49 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */ 50 #define XBF_MAPPED (1 << 3) /* buffer mapped (b_addr valid) */ 51 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */ 52 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */ 53 #define XBF_DELWRI (1 << 6) /* buffer has dirty pages */ 54 #define XBF_STALE (1 << 7) /* buffer has been staled, do not find it */ 55 56 /* I/O hints for the BIO layer */ 57 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */ 58 #define XBF_FUA (1 << 11)/* force cache write through mode */ 59 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */ 60 61 /* flags used only as arguments to access routines */ 62 #define XBF_LOCK (1 << 15)/* lock requested */ 63 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */ 64 #define XBF_DONT_BLOCK (1 << 17)/* do not block in current thread */ 65 66 /* flags used only internally */ 67 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */ 68 #define _XBF_KMEM (1 << 21)/* backed by heap memory */ 69 #define _XBF_DELWRI_Q (1 << 22)/* buffer on delwri queue */ 70 71 typedef unsigned int xfs_buf_flags_t; 72 73 #define XFS_BUF_FLAGS \ 74 { XBF_READ, "READ" }, \ 75 { XBF_WRITE, "WRITE" }, \ 76 { XBF_READ_AHEAD, "READ_AHEAD" }, \ 77 { XBF_MAPPED, "MAPPED" }, \ 78 { XBF_ASYNC, "ASYNC" }, \ 79 { XBF_DONE, "DONE" }, \ 80 { XBF_DELWRI, "DELWRI" }, \ 81 { XBF_STALE, "STALE" }, \ 82 { XBF_SYNCIO, "SYNCIO" }, \ 83 { XBF_FUA, "FUA" }, \ 84 { XBF_FLUSH, "FLUSH" }, \ 85 { XBF_LOCK, "LOCK" }, /* should never be set */\ 86 { XBF_TRYLOCK, "TRYLOCK" }, /* ditto */\ 87 { XBF_DONT_BLOCK, "DONT_BLOCK" }, /* ditto */\ 88 { _XBF_PAGES, "PAGES" }, \ 89 { _XBF_KMEM, "KMEM" }, \ 90 { _XBF_DELWRI_Q, "DELWRI_Q" } 91 92 typedef enum { 93 XBT_FORCE_FLUSH = 0, 94 } xfs_buftarg_flags_t; 95 96 typedef struct xfs_buftarg { 97 dev_t bt_dev; 98 struct block_device *bt_bdev; 99 struct backing_dev_info *bt_bdi; 100 struct xfs_mount *bt_mount; 101 unsigned int bt_bsize; 102 unsigned int bt_sshift; 103 size_t bt_smask; 104 105 /* per device delwri queue */ 106 struct task_struct *bt_task; 107 struct list_head bt_delwri_queue; 108 spinlock_t bt_delwri_lock; 109 unsigned long bt_flags; 110 111 /* LRU control structures */ 112 struct shrinker bt_shrinker; 113 struct list_head bt_lru; 114 spinlock_t bt_lru_lock; 115 unsigned int bt_lru_nr; 116 } xfs_buftarg_t; 117 118 struct xfs_buf; 119 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *); 120 121 #define XB_PAGES 2 122 123 typedef struct xfs_buf { 124 /* 125 * first cacheline holds all the fields needed for an uncontended cache 126 * hit to be fully processed. The semaphore straddles the cacheline 127 * boundary, but the counter and lock sits on the first cacheline, 128 * which is the only bit that is touched if we hit the semaphore 129 * fast-path on locking. 130 */ 131 struct rb_node b_rbnode; /* rbtree node */ 132 xfs_off_t b_file_offset; /* offset in file */ 133 size_t b_buffer_length;/* size of buffer in bytes */ 134 atomic_t b_hold; /* reference count */ 135 atomic_t b_lru_ref; /* lru reclaim ref count */ 136 xfs_buf_flags_t b_flags; /* status flags */ 137 struct semaphore b_sema; /* semaphore for lockables */ 138 139 struct list_head b_lru; /* lru list */ 140 wait_queue_head_t b_waiters; /* unpin waiters */ 141 struct list_head b_list; 142 struct xfs_perag *b_pag; /* contains rbtree root */ 143 xfs_buftarg_t *b_target; /* buffer target (device) */ 144 xfs_daddr_t b_bn; /* block number for I/O */ 145 size_t b_count_desired;/* desired transfer size */ 146 void *b_addr; /* virtual address of buffer */ 147 struct work_struct b_iodone_work; 148 xfs_buf_iodone_t b_iodone; /* I/O completion function */ 149 struct completion b_iowait; /* queue for I/O waiters */ 150 void *b_fspriv; 151 struct xfs_trans *b_transp; 152 struct page **b_pages; /* array of page pointers */ 153 struct page *b_page_array[XB_PAGES]; /* inline pages */ 154 unsigned long b_queuetime; /* time buffer was queued */ 155 atomic_t b_pin_count; /* pin count */ 156 atomic_t b_io_remaining; /* #outstanding I/O requests */ 157 unsigned int b_page_count; /* size of page array */ 158 unsigned int b_offset; /* page offset in first page */ 159 unsigned short b_error; /* error code on I/O */ 160 #ifdef XFS_BUF_LOCK_TRACKING 161 int b_last_holder; 162 #endif 163 } xfs_buf_t; 164 165 166 /* Finding and Reading Buffers */ 167 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t, 168 xfs_buf_flags_t, xfs_buf_t *); 169 #define xfs_incore(buftarg,blkno,len,lockit) \ 170 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL) 171 172 extern xfs_buf_t *xfs_buf_get(xfs_buftarg_t *, xfs_off_t, size_t, 173 xfs_buf_flags_t); 174 extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t, 175 xfs_buf_flags_t); 176 177 struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *, xfs_off_t, size_t, 178 xfs_buf_flags_t); 179 extern void xfs_buf_set_empty(struct xfs_buf *bp, size_t len); 180 extern xfs_buf_t *xfs_buf_get_uncached(struct xfs_buftarg *, size_t, int); 181 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t); 182 extern void xfs_buf_hold(xfs_buf_t *); 183 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t); 184 struct xfs_buf *xfs_buf_read_uncached(struct xfs_mount *mp, 185 struct xfs_buftarg *target, 186 xfs_daddr_t daddr, size_t length, int flags); 187 188 /* Releasing Buffers */ 189 extern void xfs_buf_free(xfs_buf_t *); 190 extern void xfs_buf_rele(xfs_buf_t *); 191 192 /* Locking and Unlocking Buffers */ 193 extern int xfs_buf_trylock(xfs_buf_t *); 194 extern void xfs_buf_lock(xfs_buf_t *); 195 extern void xfs_buf_unlock(xfs_buf_t *); 196 #define xfs_buf_islocked(bp) \ 197 ((bp)->b_sema.count <= 0) 198 199 /* Buffer Read and Write Routines */ 200 extern int xfs_bwrite(struct xfs_buf *bp); 201 202 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *); 203 extern int xfs_bdstrat_cb(struct xfs_buf *); 204 205 extern void xfs_buf_ioend(xfs_buf_t *, int); 206 extern void xfs_buf_ioerror(xfs_buf_t *, int); 207 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); 208 extern int xfs_buf_iorequest(xfs_buf_t *); 209 extern int xfs_buf_iowait(xfs_buf_t *); 210 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, 211 xfs_buf_rw_t); 212 #define xfs_buf_zero(bp, off, len) \ 213 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) 214 215 static inline int xfs_buf_geterror(xfs_buf_t *bp) 216 { 217 return bp ? bp->b_error : ENOMEM; 218 } 219 220 /* Buffer Utility Routines */ 221 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t); 222 223 /* Delayed Write Buffer Routines */ 224 extern void xfs_buf_delwri_queue(struct xfs_buf *); 225 extern void xfs_buf_delwri_dequeue(struct xfs_buf *); 226 extern void xfs_buf_delwri_promote(struct xfs_buf *); 227 228 /* Buffer Daemon Setup Routines */ 229 extern int xfs_buf_init(void); 230 extern void xfs_buf_terminate(void); 231 232 #define XFS_BUF_ZEROFLAGS(bp) \ 233 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI| \ 234 XBF_SYNCIO|XBF_FUA|XBF_FLUSH)) 235 236 void xfs_buf_stale(struct xfs_buf *bp); 237 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE) 238 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE) 239 240 #define XFS_BUF_ISDELAYWRITE(bp) ((bp)->b_flags & XBF_DELWRI) 241 242 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE) 243 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE) 244 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE) 245 246 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC) 247 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC) 248 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC) 249 250 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ) 251 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ) 252 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ) 253 254 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE) 255 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE) 256 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE) 257 258 #define XFS_BUF_ADDR(bp) ((bp)->b_bn) 259 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno)) 260 #define XFS_BUF_OFFSET(bp) ((bp)->b_file_offset) 261 #define XFS_BUF_SET_OFFSET(bp, off) ((bp)->b_file_offset = (off)) 262 #define XFS_BUF_COUNT(bp) ((bp)->b_count_desired) 263 #define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt)) 264 #define XFS_BUF_SIZE(bp) ((bp)->b_buffer_length) 265 #define XFS_BUF_SET_SIZE(bp, cnt) ((bp)->b_buffer_length = (cnt)) 266 267 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) 268 { 269 atomic_set(&bp->b_lru_ref, lru_ref); 270 } 271 272 static inline int xfs_buf_ispinned(struct xfs_buf *bp) 273 { 274 return atomic_read(&bp->b_pin_count); 275 } 276 277 static inline void xfs_buf_relse(xfs_buf_t *bp) 278 { 279 xfs_buf_unlock(bp); 280 xfs_buf_rele(bp); 281 } 282 283 /* 284 * Handling of buftargs. 285 */ 286 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, 287 struct block_device *, int, const char *); 288 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); 289 extern void xfs_wait_buftarg(xfs_buftarg_t *); 290 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int); 291 extern int xfs_flush_buftarg(xfs_buftarg_t *, int); 292 293 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) 294 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) 295 296 #endif /* __XFS_BUF_H__ */ 297