fs/xfs/linux-2.6/xfs_buf.h

   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 typedef enum {
  48         XBF_READ = (1 << 0),    /* buffer intended for reading from device */
  49         XBF_WRITE = (1 << 1),   /* buffer intended for writing to device   */
  50         XBF_MAPPED = (1 << 2),  /* buffer mapped (b_addr valid)            */
  51         XBF_ASYNC = (1 << 4),   /* initiator will not wait for completion  */
  52         XBF_DONE = (1 << 5),    /* all pages in the buffer uptodate        */
  53         XBF_DELWRI = (1 << 6),  /* buffer has dirty pages                  */
  54         XBF_STALE = (1 << 7),   /* buffer has been staled, do not find it  */
  55         XBF_FS_MANAGED = (1 << 8),  /* filesystem controls freeing memory  */
  56         XBF_ORDERED = (1 << 11),    /* use ordered writes                  */
  57         XBF_READ_AHEAD = (1 << 12), /* asynchronous read-ahead             */
  58
  59         /* flags used only as arguments to access routines */
  60         XBF_LOCK = (1 << 14),       /* lock requested                      */
  61         XBF_TRYLOCK = (1 << 15),    /* lock requested, but do not wait     */
  62         XBF_DONT_BLOCK = (1 << 16), /* do not block in current thread      */
  63
  64         /* flags used only internally */
  65         _XBF_PAGE_CACHE = (1 << 17),/* backed by pagecache                 */
  66         _XBF_KMEM_ALLOC = (1 << 18),/* backed by kmem_alloc()              */
  67         _XBF_RUN_QUEUES = (1 << 19),/* run block device task queue         */
  68         _XBF_DELWRI_Q = (1 << 21),   /* buffer on delwri queue             */
  69 } xfs_buf_flags_t;
  70
  71 typedef enum {
  72         XBT_FORCE_SLEEP = (0 << 1),
  73         XBT_FORCE_FLUSH = (1 << 1),
  74 } xfs_buftarg_flags_t;
  75
  76 typedef struct xfs_bufhash {
  77         struct list_head        bh_list;
  78         spinlock_t              bh_lock;
  79 } xfs_bufhash_t;
  80
  81 typedef struct xfs_buftarg {
  82         dev_t                   bt_dev;
  83         struct block_device     *bt_bdev;
  84         struct address_space    *bt_mapping;
  85         unsigned int            bt_bsize;
  86         unsigned int            bt_sshift;
  87         size_t                  bt_smask;
  88
  89         /* per device buffer hash table */
  90         uint                    bt_hashmask;
  91         uint                    bt_hashshift;
  92         xfs_bufhash_t           *bt_hash;
  93
  94         /* per device delwri queue */
  95         struct task_struct      *bt_task;
  96         struct list_head        bt_list;
  97         struct list_head        bt_delwrite_queue;
  98         spinlock_t              bt_delwrite_lock;
  99         unsigned long           bt_flags;
 100 } xfs_buftarg_t;
 101
 102 /*
 103  *      xfs_buf_t:  Buffer structure for pagecache-based buffers
 104  *
 105  * This buffer structure is used by the pagecache buffer management routines
 106  * to refer to an assembly of pages forming a logical buffer.
 107  *
 108  * The buffer structure is used on a temporary basis only, and discarded when
 109  * released.  The real data storage is recorded in the pagecache. Buffers are
 110  * hashed to the block device on which the file system resides.
 111  */
 112
 113 struct xfs_buf;
 114 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
 115 typedef void (*xfs_buf_relse_t)(struct xfs_buf *);
 116 typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);
 117
 118 #define XB_PAGES        2
 119
 120 typedef struct xfs_buf {
 121         struct semaphore        b_sema;         /* semaphore for lockables */
 122         unsigned long           b_queuetime;    /* time buffer was queued */
 123         atomic_t                b_pin_count;    /* pin count */
 124         wait_queue_head_t       b_waiters;      /* unpin waiters */
 125         struct list_head        b_list;
 126         xfs_buf_flags_t         b_flags;        /* status flags */
 127         struct list_head        b_hash_list;    /* hash table list */
 128         xfs_bufhash_t           *b_hash;        /* hash table list start */
 129         xfs_buftarg_t           *b_target;      /* buffer target (device) */
 130         atomic_t                b_hold;         /* reference count */
 131         xfs_daddr_t             b_bn;           /* block number for I/O */
 132         xfs_off_t               b_file_offset;  /* offset in file */
 133         size_t                  b_buffer_length;/* size of buffer in bytes */
 134         size_t                  b_count_desired;/* desired transfer size */
 135         void                    *b_addr;        /* virtual address of buffer */
 136         struct work_struct      b_iodone_work;
 137         atomic_t                b_io_remaining; /* #outstanding I/O requests */
 138         xfs_buf_iodone_t        b_iodone;       /* I/O completion function */
 139         xfs_buf_relse_t         b_relse;        /* releasing function */
 140         xfs_buf_bdstrat_t       b_strat;        /* pre-write function */
 141         struct semaphore        b_iodonesema;   /* Semaphore for I/O waiters */
 142         void                    *b_fspriv;
 143         void                    *b_fspriv2;
 144         void                    *b_fspriv3;
 145         unsigned short          b_error;        /* error code on I/O */
 146         unsigned short          b_locked;       /* page array is locked */
 147         unsigned int            b_page_count;   /* size of page array */
 148         unsigned int            b_offset;       /* page offset in first page */
 149         struct page             **b_pages;      /* array of page pointers */
 150         struct page             *b_page_array[XB_PAGES]; /* inline pages */
 151 #ifdef XFS_BUF_LOCK_TRACKING
 152         int                     b_last_holder;
 153 #endif
 154 } xfs_buf_t;
 155
 156
 157 /* Finding and Reading Buffers */
 158 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
 159                                 xfs_buf_flags_t, xfs_buf_t *);
 160 #define xfs_incore(buftarg,blkno,len,lockit) \
 161         _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
 162
 163 extern xfs_buf_t *xfs_buf_get_flags(xfs_buftarg_t *, xfs_off_t, size_t,
 164                                 xfs_buf_flags_t);
 165 #define xfs_buf_get(target, blkno, len, flags) \
 166         xfs_buf_get_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)
 167
 168 extern xfs_buf_t *xfs_buf_read_flags(xfs_buftarg_t *, xfs_off_t, size_t,
 169                                 xfs_buf_flags_t);
 170 #define xfs_buf_read(target, blkno, len, flags) \
 171         xfs_buf_read_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)
 172
 173 extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
 174 extern xfs_buf_t *xfs_buf_get_noaddr(size_t, xfs_buftarg_t *);
 175 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
 176 extern void xfs_buf_hold(xfs_buf_t *);
 177 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t,
 178                                 xfs_buf_flags_t);
 179
 180 /* Releasing Buffers */
 181 extern void xfs_buf_free(xfs_buf_t *);
 182 extern void xfs_buf_rele(xfs_buf_t *);
 183
 184 /* Locking and Unlocking Buffers */
 185 extern int xfs_buf_cond_lock(xfs_buf_t *);
 186 extern int xfs_buf_lock_value(xfs_buf_t *);
 187 extern void xfs_buf_lock(xfs_buf_t *);
 188 extern void xfs_buf_unlock(xfs_buf_t *);
 189
 190 /* Buffer Read and Write Routines */
 191 extern void xfs_buf_ioend(xfs_buf_t *,  int);
 192 extern void xfs_buf_ioerror(xfs_buf_t *, int);
 193 extern int xfs_buf_iostart(xfs_buf_t *, xfs_buf_flags_t);
 194 extern int xfs_buf_iorequest(xfs_buf_t *);
 195 extern int xfs_buf_iowait(xfs_buf_t *);
 196 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, xfs_caddr_t,
 197                                 xfs_buf_rw_t);
 198
 199 static inline int xfs_buf_iostrategy(xfs_buf_t *bp)
 200 {
 201         return bp->b_strat ? bp->b_strat(bp) : xfs_buf_iorequest(bp);
 202 }
 203
 204 static inline int xfs_buf_geterror(xfs_buf_t *bp)
 205 {
 206         return bp ? bp->b_error : ENOMEM;
 207 }
 208
 209 /* Buffer Utility Routines */
 210 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
 211
 212 /* Pinning Buffer Storage in Memory */
 213 extern void xfs_buf_pin(xfs_buf_t *);
 214 extern void xfs_buf_unpin(xfs_buf_t *);
 215 extern int xfs_buf_ispin(xfs_buf_t *);
 216
 217 /* Delayed Write Buffer Routines */
 218 extern void xfs_buf_delwri_dequeue(xfs_buf_t *);
 219
 220 /* Buffer Daemon Setup Routines */
 221 extern int xfs_buf_init(void);
 222 extern void xfs_buf_terminate(void);
 223
 224 #ifdef XFS_BUF_TRACE
 225 extern ktrace_t *xfs_buf_trace_buf;
 226 extern void xfs_buf_trace(xfs_buf_t *, char *, void *, void *);
 227 #else
 228 #define xfs_buf_trace(bp,id,ptr,ra)     do { } while (0)
 229 #endif
 230
 231 #define xfs_buf_target_name(target)     \
 232         ({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })
 233
 234
 235 #define XFS_B_ASYNC             XBF_ASYNC
 236 #define XFS_B_DELWRI            XBF_DELWRI
 237 #define XFS_B_READ              XBF_READ
 238 #define XFS_B_WRITE             XBF_WRITE
 239 #define XFS_B_STALE             XBF_STALE
 240
 241 #define XFS_BUF_TRYLOCK         XBF_TRYLOCK
 242 #define XFS_INCORE_TRYLOCK      XBF_TRYLOCK
 243 #define XFS_BUF_LOCK            XBF_LOCK
 244 #define XFS_BUF_MAPPED          XBF_MAPPED
 245
 246 #define BUF_BUSY                XBF_DONT_BLOCK
 247
 248 #define XFS_BUF_BFLAGS(bp)      ((bp)->b_flags)
 249 #define XFS_BUF_ZEROFLAGS(bp)   ((bp)->b_flags &= \
 250                 ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI|XBF_ORDERED))
 251
 252 #define XFS_BUF_STALE(bp)       ((bp)->b_flags |= XFS_B_STALE)
 253 #define XFS_BUF_UNSTALE(bp)     ((bp)->b_flags &= ~XFS_B_STALE)
 254 #define XFS_BUF_ISSTALE(bp)     ((bp)->b_flags & XFS_B_STALE)
 255 #define XFS_BUF_SUPER_STALE(bp) do {                            \
 256                                         XFS_BUF_STALE(bp);      \
 257                                         xfs_buf_delwri_dequeue(bp);     \
 258                                         XFS_BUF_DONE(bp);       \
 259                                 } while (0)
 260
 261 #define XFS_BUF_MANAGE          XBF_FS_MANAGED
 262 #define XFS_BUF_UNMANAGE(bp)    ((bp)->b_flags &= ~XBF_FS_MANAGED)
 263
 264 #define XFS_BUF_DELAYWRITE(bp)          ((bp)->b_flags |= XBF_DELWRI)
 265 #define XFS_BUF_UNDELAYWRITE(bp)        xfs_buf_delwri_dequeue(bp)
 266 #define XFS_BUF_ISDELAYWRITE(bp)        ((bp)->b_flags & XBF_DELWRI)
 267
 268 #define XFS_BUF_ERROR(bp,no)    xfs_buf_ioerror(bp,no)
 269 #define XFS_BUF_GETERROR(bp)    xfs_buf_geterror(bp)
 270 #define XFS_BUF_ISERROR(bp)     (xfs_buf_geterror(bp) ? 1 : 0)
 271
 272 #define XFS_BUF_DONE(bp)        ((bp)->b_flags |= XBF_DONE)
 273 #define XFS_BUF_UNDONE(bp)      ((bp)->b_flags &= ~XBF_DONE)
 274 #define XFS_BUF_ISDONE(bp)      ((bp)->b_flags & XBF_DONE)
 275
 276 #define XFS_BUF_BUSY(bp)        do { } while (0)
 277 #define XFS_BUF_UNBUSY(bp)      do { } while (0)
 278 #define XFS_BUF_ISBUSY(bp)      (1)
 279
 280 #define XFS_BUF_ASYNC(bp)       ((bp)->b_flags |= XBF_ASYNC)
 281 #define XFS_BUF_UNASYNC(bp)     ((bp)->b_flags &= ~XBF_ASYNC)
 282 #define XFS_BUF_ISASYNC(bp)     ((bp)->b_flags & XBF_ASYNC)
 283
 284 #define XFS_BUF_ORDERED(bp)     ((bp)->b_flags |= XBF_ORDERED)
 285 #define XFS_BUF_UNORDERED(bp)   ((bp)->b_flags &= ~XBF_ORDERED)
 286 #define XFS_BUF_ISORDERED(bp)   ((bp)->b_flags & XBF_ORDERED)
 287
 288 #define XFS_BUF_SHUT(bp)        do { } while (0)
 289 #define XFS_BUF_UNSHUT(bp)      do { } while (0)
 290 #define XFS_BUF_ISSHUT(bp)      (0)
 291
 292 #define XFS_BUF_HOLD(bp)        xfs_buf_hold(bp)
 293 #define XFS_BUF_READ(bp)        ((bp)->b_flags |= XBF_READ)
 294 #define XFS_BUF_UNREAD(bp)      ((bp)->b_flags &= ~XBF_READ)
 295 #define XFS_BUF_ISREAD(bp)      ((bp)->b_flags & XBF_READ)
 296
 297 #define XFS_BUF_WRITE(bp)       ((bp)->b_flags |= XBF_WRITE)
 298 #define XFS_BUF_UNWRITE(bp)     ((bp)->b_flags &= ~XBF_WRITE)
 299 #define XFS_BUF_ISWRITE(bp)     ((bp)->b_flags & XBF_WRITE)
 300
 301 #define XFS_BUF_IODONE_FUNC(bp)                 ((bp)->b_iodone)
 302 #define XFS_BUF_SET_IODONE_FUNC(bp, func)       ((bp)->b_iodone = (func))
 303 #define XFS_BUF_CLR_IODONE_FUNC(bp)             ((bp)->b_iodone = NULL)
 304 #define XFS_BUF_SET_BDSTRAT_FUNC(bp, func)      ((bp)->b_strat = (func))
 305 #define XFS_BUF_CLR_BDSTRAT_FUNC(bp)            ((bp)->b_strat = NULL)
 306
 307 #define XFS_BUF_FSPRIVATE(bp, type)             ((type)(bp)->b_fspriv)
 308 #define XFS_BUF_SET_FSPRIVATE(bp, val)          ((bp)->b_fspriv = (void*)(val))
 309 #define XFS_BUF_FSPRIVATE2(bp, type)            ((type)(bp)->b_fspriv2)
 310 #define XFS_BUF_SET_FSPRIVATE2(bp, val)         ((bp)->b_fspriv2 = (void*)(val))
 311 #define XFS_BUF_FSPRIVATE3(bp, type)            ((type)(bp)->b_fspriv3)
 312 #define XFS_BUF_SET_FSPRIVATE3(bp, val)         ((bp)->b_fspriv3 = (void*)(val))
 313 #define XFS_BUF_SET_START(bp)                   do { } while (0)
 314 #define XFS_BUF_SET_BRELSE_FUNC(bp, func)       ((bp)->b_relse = (func))
 315
 316 #define XFS_BUF_PTR(bp)                 (xfs_caddr_t)((bp)->b_addr)
 317 #define XFS_BUF_SET_PTR(bp, val, cnt)   xfs_buf_associate_memory(bp, val, cnt)
 318 #define XFS_BUF_ADDR(bp)                ((bp)->b_bn)
 319 #define XFS_BUF_SET_ADDR(bp, bno)       ((bp)->b_bn = (xfs_daddr_t)(bno))
 320 #define XFS_BUF_OFFSET(bp)              ((bp)->b_file_offset)
 321 #define XFS_BUF_SET_OFFSET(bp, off)     ((bp)->b_file_offset = (off))
 322 #define XFS_BUF_COUNT(bp)               ((bp)->b_count_desired)
 323 #define XFS_BUF_SET_COUNT(bp, cnt)      ((bp)->b_count_desired = (cnt))
 324 #define XFS_BUF_SIZE(bp)                ((bp)->b_buffer_length)
 325 #define XFS_BUF_SET_SIZE(bp, cnt)       ((bp)->b_buffer_length = (cnt))
 326
 327 #define XFS_BUF_SET_VTYPE_REF(bp, type, ref)    do { } while (0)
 328 #define XFS_BUF_SET_VTYPE(bp, type)             do { } while (0)
 329 #define XFS_BUF_SET_REF(bp, ref)                do { } while (0)
 330
 331 #define XFS_BUF_ISPINNED(bp)    xfs_buf_ispin(bp)
 332
 333 #define XFS_BUF_VALUSEMA(bp)    xfs_buf_lock_value(bp)
 334 #define XFS_BUF_CPSEMA(bp)      (xfs_buf_cond_lock(bp) == 0)
 335 #define XFS_BUF_VSEMA(bp)       xfs_buf_unlock(bp)
 336 #define XFS_BUF_PSEMA(bp,x)     xfs_buf_lock(bp)
 337 #define XFS_BUF_V_IODONESEMA(bp) up(&bp->b_iodonesema);
 338
 339 #define XFS_BUF_SET_TARGET(bp, target)  ((bp)->b_target = (target))
 340 #define XFS_BUF_TARGET(bp)              ((bp)->b_target)
 341 #define XFS_BUFTARG_NAME(target)        xfs_buf_target_name(target)
 342
 343 static inline int xfs_bawrite(void *mp, xfs_buf_t *bp)
 344 {
 345         bp->b_fspriv3 = mp;
 346         bp->b_strat = xfs_bdstrat_cb;
 347         xfs_buf_delwri_dequeue(bp);
 348         return xfs_buf_iostart(bp, XBF_WRITE | XBF_ASYNC | _XBF_RUN_QUEUES);
 349 }
 350
 351 static inline void xfs_buf_relse(xfs_buf_t *bp)
 352 {
 353         if (!bp->b_relse)
 354                 xfs_buf_unlock(bp);
 355         xfs_buf_rele(bp);
 356 }
 357
 358 #define xfs_bpin(bp)            xfs_buf_pin(bp)
 359 #define xfs_bunpin(bp)          xfs_buf_unpin(bp)
 360
 361 #define xfs_buftrace(id, bp)    \
 362             xfs_buf_trace(bp, id, NULL, (void *)__builtin_return_address(0))
 363
 364 #define xfs_biodone(bp)         xfs_buf_ioend(bp, 0)
 365
 366 #define xfs_biomove(bp, off, len, data, rw) \
 367             xfs_buf_iomove((bp), (off), (len), (data), \
 368                 ((rw) == XFS_B_WRITE) ? XBRW_WRITE : XBRW_READ)
 369
 370 #define xfs_biozero(bp, off, len) \
 371             xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
 372
 373
 374 static inline int XFS_bwrite(xfs_buf_t *bp)
 375 {
 376         int     iowait = (bp->b_flags & XBF_ASYNC) == 0;
 377         int     error = 0;
 378
 379         if (!iowait)
 380                 bp->b_flags |= _XBF_RUN_QUEUES;
 381
 382         xfs_buf_delwri_dequeue(bp);
 383         xfs_buf_iostrategy(bp);
 384         if (iowait) {
 385                 error = xfs_buf_iowait(bp);
 386                 xfs_buf_relse(bp);
 387         }
 388         return error;
 389 }
 390
 391 static inline int xfs_bdwrite(void *mp, xfs_buf_t *bp)
 392 {
 393         bp->b_strat = xfs_bdstrat_cb;
 394         bp->b_fspriv3 = mp;
 395         return xfs_buf_iostart(bp, XBF_DELWRI | XBF_ASYNC);
 396 }
 397
 398 #define XFS_bdstrat(bp) xfs_buf_iorequest(bp)
 399
 400 #define xfs_iowait(bp)  xfs_buf_iowait(bp)
 401
 402 #define xfs_baread(target, rablkno, ralen)  \
 403         xfs_buf_readahead((target), (rablkno), (ralen), XBF_DONT_BLOCK)
 404
 405
 406 /*
 407  *      Handling of buftargs.
 408  */
 409 extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
 410 extern void xfs_free_buftarg(xfs_buftarg_t *, int);
 411 extern void xfs_wait_buftarg(xfs_buftarg_t *);
 412 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
 413 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
 414
 415 #define xfs_getsize_buftarg(buftarg)    block_size((buftarg)->bt_bdev)
 416 #define xfs_readonly_buftarg(buftarg)   bdev_read_only((buftarg)->bt_bdev)
 417
 418 #define xfs_binval(buftarg)             xfs_flush_buftarg(buftarg, 1)
 419 #define XFS_bflush(buftarg)             xfs_flush_buftarg(buftarg, 1)
 420
 421 #endif  /* __XFS_BUF_H__ */