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_PAGES = (1 << 18),     /* backed by refcounted pages          */
  67         _XBF_RUN_QUEUES = (1 << 19),/* run block device task queue         */
  68         _XBF_DELWRI_Q = (1 << 21),   /* buffer on delwri queue             */
  69
  70         /*
  71          * Special flag for supporting metadata blocks smaller than a FSB.
  72          *
  73          * In this case we can have multiple xfs_buf_t on a single page and
  74          * need to lock out concurrent xfs_buf_t readers as they only
  75          * serialise access to the buffer.
  76          *
  77          * If the FSB size >= PAGE_CACHE_SIZE case, we have no serialisation
  78          * between reads of the page. Hence we can have one thread read the
  79          * page and modify it, but then race with another thread that thinks
  80          * the page is not up-to-date and hence reads it again.
  81          *
  82          * The result is that the first modifcation to the page is lost.
  83          * This sort of AGF/AGI reading race can happen when unlinking inodes
  84          * that require truncation and results in the AGI unlinked list
  85          * modifications being lost.
  86          */
  87         _XBF_PAGE_LOCKED = (1 << 22),
  88
  89         /*
  90          * If we try a barrier write, but it fails we have to communicate
  91          * this to the upper layers.  Unfortunately b_error gets overwritten
  92          * when the buffer is re-issued so we have to add another flag to
  93          * keep this information.
  94          */
  95         _XFS_BARRIER_FAILED = (1 << 23),
  96 } xfs_buf_flags_t;
  97
  98 typedef enum {
  99         XBT_FORCE_SLEEP = 0,
 100         XBT_FORCE_FLUSH = 1,
 101 } xfs_buftarg_flags_t;
 102
 103 typedef struct xfs_bufhash {
 104         struct list_head        bh_list;
 105         spinlock_t              bh_lock;
 106 } xfs_bufhash_t;
 107
 108 typedef struct xfs_buftarg {
 109         dev_t                   bt_dev;
 110         struct block_device     *bt_bdev;
 111         struct address_space    *bt_mapping;
 112         unsigned int            bt_bsize;
 113         unsigned int            bt_sshift;
 114         size_t                  bt_smask;
 115
 116         /* per device buffer hash table */
 117         uint                    bt_hashmask;
 118         uint                    bt_hashshift;
 119         xfs_bufhash_t           *bt_hash;
 120
 121         /* per device delwri queue */
 122         struct task_struct      *bt_task;
 123         struct list_head        bt_list;
 124         struct list_head        bt_delwrite_queue;
 125         spinlock_t              bt_delwrite_lock;
 126         unsigned long           bt_flags;
 127 } xfs_buftarg_t;
 128
 129 /*
 130  *      xfs_buf_t:  Buffer structure for pagecache-based buffers
 131  *
 132  * This buffer structure is used by the pagecache buffer management routines
 133  * to refer to an assembly of pages forming a logical buffer.
 134  *
 135  * The buffer structure is used on a temporary basis only, and discarded when
 136  * released.  The real data storage is recorded in the pagecache. Buffers are
 137  * hashed to the block device on which the file system resides.
 138  */
 139
 140 struct xfs_buf;
 141 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
 142 typedef void (*xfs_buf_relse_t)(struct xfs_buf *);
 143 typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);
 144
 145 #define XB_PAGES        2
 146
 147 typedef struct xfs_buf {
 148         struct semaphore        b_sema;         /* semaphore for lockables */
 149         unsigned long           b_queuetime;    /* time buffer was queued */
 150         atomic_t                b_pin_count;    /* pin count */
 151         wait_queue_head_t       b_waiters;      /* unpin waiters */
 152         struct list_head        b_list;
 153         xfs_buf_flags_t         b_flags;        /* status flags */
 154         struct list_head        b_hash_list;    /* hash table list */
 155         xfs_bufhash_t           *b_hash;        /* hash table list start */
 156         xfs_buftarg_t           *b_target;      /* buffer target (device) */
 157         atomic_t                b_hold;         /* reference count */
 158         xfs_daddr_t             b_bn;           /* block number for I/O */
 159         xfs_off_t               b_file_offset;  /* offset in file */
 160         size_t                  b_buffer_length;/* size of buffer in bytes */
 161         size_t                  b_count_desired;/* desired transfer size */
 162         void                    *b_addr;        /* virtual address of buffer */
 163         struct work_struct      b_iodone_work;
 164         atomic_t                b_io_remaining; /* #outstanding I/O requests */
 165         xfs_buf_iodone_t        b_iodone;       /* I/O completion function */
 166         xfs_buf_relse_t         b_relse;        /* releasing function */
 167         xfs_buf_bdstrat_t       b_strat;        /* pre-write function */
 168         struct completion       b_iowait;       /* queue for I/O waiters */
 169         void                    *b_fspriv;
 170         void                    *b_fspriv2;
 171         struct xfs_mount        *b_mount;
 172         unsigned short          b_error;        /* error code on I/O */
 173         unsigned int            b_page_count;   /* size of page array */
 174         unsigned int            b_offset;       /* page offset in first page */
 175         struct page             **b_pages;      /* array of page pointers */
 176         struct page             *b_page_array[XB_PAGES]; /* inline pages */
 177 #ifdef XFS_BUF_LOCK_TRACKING
 178         int                     b_last_holder;
 179 #endif
 180 } xfs_buf_t;
 181
 182
 183 /* Finding and Reading Buffers */
 184 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
 185                                 xfs_buf_flags_t, xfs_buf_t *);
 186 #define xfs_incore(buftarg,blkno,len,lockit) \
 187         _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
 188
 189 extern xfs_buf_t *xfs_buf_get_flags(xfs_buftarg_t *, xfs_off_t, size_t,
 190                                 xfs_buf_flags_t);
 191 #define xfs_buf_get(target, blkno, len, flags) \
 192         xfs_buf_get_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)
 193
 194 extern xfs_buf_t *xfs_buf_read_flags(xfs_buftarg_t *, xfs_off_t, size_t,
 195                                 xfs_buf_flags_t);
 196 #define xfs_buf_read(target, blkno, len, flags) \
 197         xfs_buf_read_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)
 198
 199 extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
 200 extern xfs_buf_t *xfs_buf_get_noaddr(size_t, xfs_buftarg_t *);
 201 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
 202 extern void xfs_buf_hold(xfs_buf_t *);
 203 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t,
 204                                 xfs_buf_flags_t);
 205
 206 /* Releasing Buffers */
 207 extern void xfs_buf_free(xfs_buf_t *);
 208 extern void xfs_buf_rele(xfs_buf_t *);
 209
 210 /* Locking and Unlocking Buffers */
 211 extern int xfs_buf_cond_lock(xfs_buf_t *);
 212 extern int xfs_buf_lock_value(xfs_buf_t *);
 213 extern void xfs_buf_lock(xfs_buf_t *);
 214 extern void xfs_buf_unlock(xfs_buf_t *);
 215
 216 /* Buffer Read and Write Routines */
 217 extern int xfs_bawrite(void *mp, xfs_buf_t *bp);
 218 extern void xfs_bdwrite(void *mp, xfs_buf_t *bp);
 219 extern void xfs_buf_ioend(xfs_buf_t *,  int);
 220 extern void xfs_buf_ioerror(xfs_buf_t *, int);
 221 extern int xfs_buf_iorequest(xfs_buf_t *);
 222 extern int xfs_buf_iowait(xfs_buf_t *);
 223 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, xfs_caddr_t,
 224                                 xfs_buf_rw_t);
 225
 226 static inline int xfs_buf_iostrategy(xfs_buf_t *bp)
 227 {
 228         return bp->b_strat ? bp->b_strat(bp) : xfs_buf_iorequest(bp);
 229 }
 230
 231 static inline int xfs_buf_geterror(xfs_buf_t *bp)
 232 {
 233         return bp ? bp->b_error : ENOMEM;
 234 }
 235
 236 /* Buffer Utility Routines */
 237 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
 238
 239 /* Pinning Buffer Storage in Memory */
 240 extern void xfs_buf_pin(xfs_buf_t *);
 241 extern void xfs_buf_unpin(xfs_buf_t *);
 242 extern int xfs_buf_ispin(xfs_buf_t *);
 243
 244 /* Delayed Write Buffer Routines */
 245 extern void xfs_buf_delwri_dequeue(xfs_buf_t *);
 246
 247 /* Buffer Daemon Setup Routines */
 248 extern int xfs_buf_init(void);
 249 extern void xfs_buf_terminate(void);
 250
 251 #ifdef XFS_BUF_TRACE
 252 extern ktrace_t *xfs_buf_trace_buf;
 253 extern void xfs_buf_trace(xfs_buf_t *, char *, void *, void *);
 254 #else
 255 #define xfs_buf_trace(bp,id,ptr,ra)     do { } while (0)
 256 #endif
 257
 258 #define xfs_buf_target_name(target)     \
 259         ({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })
 260
 261
 262 #define XFS_B_ASYNC             XBF_ASYNC
 263 #define XFS_B_DELWRI            XBF_DELWRI
 264 #define XFS_B_READ              XBF_READ
 265 #define XFS_B_WRITE             XBF_WRITE
 266 #define XFS_B_STALE             XBF_STALE
 267
 268 #define XFS_BUF_TRYLOCK         XBF_TRYLOCK
 269 #define XFS_INCORE_TRYLOCK      XBF_TRYLOCK
 270 #define XFS_BUF_LOCK            XBF_LOCK
 271 #define XFS_BUF_MAPPED          XBF_MAPPED
 272
 273 #define BUF_BUSY                XBF_DONT_BLOCK
 274
 275 #define XFS_BUF_BFLAGS(bp)      ((bp)->b_flags)
 276 #define XFS_BUF_ZEROFLAGS(bp)   ((bp)->b_flags &= \
 277                 ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI|XBF_ORDERED))
 278
 279 #define XFS_BUF_STALE(bp)       ((bp)->b_flags |= XFS_B_STALE)
 280 #define XFS_BUF_UNSTALE(bp)     ((bp)->b_flags &= ~XFS_B_STALE)
 281 #define XFS_BUF_ISSTALE(bp)     ((bp)->b_flags & XFS_B_STALE)
 282 #define XFS_BUF_SUPER_STALE(bp) do {                            \
 283                                         XFS_BUF_STALE(bp);      \
 284                                         xfs_buf_delwri_dequeue(bp);     \
 285                                         XFS_BUF_DONE(bp);       \
 286                                 } while (0)
 287
 288 #define XFS_BUF_MANAGE          XBF_FS_MANAGED
 289 #define XFS_BUF_UNMANAGE(bp)    ((bp)->b_flags &= ~XBF_FS_MANAGED)
 290
 291 #define XFS_BUF_DELAYWRITE(bp)          ((bp)->b_flags |= XBF_DELWRI)
 292 #define XFS_BUF_UNDELAYWRITE(bp)        xfs_buf_delwri_dequeue(bp)
 293 #define XFS_BUF_ISDELAYWRITE(bp)        ((bp)->b_flags & XBF_DELWRI)
 294
 295 #define XFS_BUF_ERROR(bp,no)    xfs_buf_ioerror(bp,no)
 296 #define XFS_BUF_GETERROR(bp)    xfs_buf_geterror(bp)
 297 #define XFS_BUF_ISERROR(bp)     (xfs_buf_geterror(bp) ? 1 : 0)
 298
 299 #define XFS_BUF_DONE(bp)        ((bp)->b_flags |= XBF_DONE)
 300 #define XFS_BUF_UNDONE(bp)      ((bp)->b_flags &= ~XBF_DONE)
 301 #define XFS_BUF_ISDONE(bp)      ((bp)->b_flags & XBF_DONE)
 302
 303 #define XFS_BUF_BUSY(bp)        do { } while (0)
 304 #define XFS_BUF_UNBUSY(bp)      do { } while (0)
 305 #define XFS_BUF_ISBUSY(bp)      (1)
 306
 307 #define XFS_BUF_ASYNC(bp)       ((bp)->b_flags |= XBF_ASYNC)
 308 #define XFS_BUF_UNASYNC(bp)     ((bp)->b_flags &= ~XBF_ASYNC)
 309 #define XFS_BUF_ISASYNC(bp)     ((bp)->b_flags & XBF_ASYNC)
 310
 311 #define XFS_BUF_ORDERED(bp)     ((bp)->b_flags |= XBF_ORDERED)
 312 #define XFS_BUF_UNORDERED(bp)   ((bp)->b_flags &= ~XBF_ORDERED)
 313 #define XFS_BUF_ISORDERED(bp)   ((bp)->b_flags & XBF_ORDERED)
 314
 315 #define XFS_BUF_HOLD(bp)        xfs_buf_hold(bp)
 316 #define XFS_BUF_READ(bp)        ((bp)->b_flags |= XBF_READ)
 317 #define XFS_BUF_UNREAD(bp)      ((bp)->b_flags &= ~XBF_READ)
 318 #define XFS_BUF_ISREAD(bp)      ((bp)->b_flags & XBF_READ)
 319
 320 #define XFS_BUF_WRITE(bp)       ((bp)->b_flags |= XBF_WRITE)
 321 #define XFS_BUF_UNWRITE(bp)     ((bp)->b_flags &= ~XBF_WRITE)
 322 #define XFS_BUF_ISWRITE(bp)     ((bp)->b_flags & XBF_WRITE)
 323
 324 #define XFS_BUF_IODONE_FUNC(bp)                 ((bp)->b_iodone)
 325 #define XFS_BUF_SET_IODONE_FUNC(bp, func)       ((bp)->b_iodone = (func))
 326 #define XFS_BUF_CLR_IODONE_FUNC(bp)             ((bp)->b_iodone = NULL)
 327 #define XFS_BUF_SET_BDSTRAT_FUNC(bp, func)      ((bp)->b_strat = (func))
 328 #define XFS_BUF_CLR_BDSTRAT_FUNC(bp)            ((bp)->b_strat = NULL)
 329
 330 #define XFS_BUF_FSPRIVATE(bp, type)             ((type)(bp)->b_fspriv)
 331 #define XFS_BUF_SET_FSPRIVATE(bp, val)          ((bp)->b_fspriv = (void*)(val))
 332 #define XFS_BUF_FSPRIVATE2(bp, type)            ((type)(bp)->b_fspriv2)
 333 #define XFS_BUF_SET_FSPRIVATE2(bp, val)         ((bp)->b_fspriv2 = (void*)(val))
 334 #define XFS_BUF_SET_START(bp)                   do { } while (0)
 335 #define XFS_BUF_SET_BRELSE_FUNC(bp, func)       ((bp)->b_relse = (func))
 336
 337 #define XFS_BUF_PTR(bp)                 (xfs_caddr_t)((bp)->b_addr)
 338 #define XFS_BUF_SET_PTR(bp, val, cnt)   xfs_buf_associate_memory(bp, val, cnt)
 339 #define XFS_BUF_ADDR(bp)                ((bp)->b_bn)
 340 #define XFS_BUF_SET_ADDR(bp, bno)       ((bp)->b_bn = (xfs_daddr_t)(bno))
 341 #define XFS_BUF_OFFSET(bp)              ((bp)->b_file_offset)
 342 #define XFS_BUF_SET_OFFSET(bp, off)     ((bp)->b_file_offset = (off))
 343 #define XFS_BUF_COUNT(bp)               ((bp)->b_count_desired)
 344 #define XFS_BUF_SET_COUNT(bp, cnt)      ((bp)->b_count_desired = (cnt))
 345 #define XFS_BUF_SIZE(bp)                ((bp)->b_buffer_length)
 346 #define XFS_BUF_SET_SIZE(bp, cnt)       ((bp)->b_buffer_length = (cnt))
 347
 348 #define XFS_BUF_SET_VTYPE_REF(bp, type, ref)    do { } while (0)
 349 #define XFS_BUF_SET_VTYPE(bp, type)             do { } while (0)
 350 #define XFS_BUF_SET_REF(bp, ref)                do { } while (0)
 351
 352 #define XFS_BUF_ISPINNED(bp)    xfs_buf_ispin(bp)
 353
 354 #define XFS_BUF_VALUSEMA(bp)    xfs_buf_lock_value(bp)
 355 #define XFS_BUF_CPSEMA(bp)      (xfs_buf_cond_lock(bp) == 0)
 356 #define XFS_BUF_VSEMA(bp)       xfs_buf_unlock(bp)
 357 #define XFS_BUF_PSEMA(bp,x)     xfs_buf_lock(bp)
 358 #define XFS_BUF_FINISH_IOWAIT(bp)       complete(&bp->b_iowait);
 359
 360 #define XFS_BUF_SET_TARGET(bp, target)  ((bp)->b_target = (target))
 361 #define XFS_BUF_TARGET(bp)              ((bp)->b_target)
 362 #define XFS_BUFTARG_NAME(target)        xfs_buf_target_name(target)
 363
 364 static inline void xfs_buf_relse(xfs_buf_t *bp)
 365 {
 366         if (!bp->b_relse)
 367                 xfs_buf_unlock(bp);
 368         xfs_buf_rele(bp);
 369 }
 370
 371 #define xfs_bpin(bp)            xfs_buf_pin(bp)
 372 #define xfs_bunpin(bp)          xfs_buf_unpin(bp)
 373
 374 #define xfs_buftrace(id, bp)    \
 375             xfs_buf_trace(bp, id, NULL, (void *)__builtin_return_address(0))
 376
 377 #define xfs_biodone(bp)         xfs_buf_ioend(bp, 0)
 378
 379 #define xfs_biomove(bp, off, len, data, rw) \
 380             xfs_buf_iomove((bp), (off), (len), (data), \
 381                 ((rw) == XFS_B_WRITE) ? XBRW_WRITE : XBRW_READ)
 382
 383 #define xfs_biozero(bp, off, len) \
 384             xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
 385
 386
 387 static inline int XFS_bwrite(xfs_buf_t *bp)
 388 {
 389         int     iowait = (bp->b_flags & XBF_ASYNC) == 0;
 390         int     error = 0;
 391
 392         if (!iowait)
 393                 bp->b_flags |= _XBF_RUN_QUEUES;
 394
 395         xfs_buf_delwri_dequeue(bp);
 396         xfs_buf_iostrategy(bp);
 397         if (iowait) {
 398                 error = xfs_buf_iowait(bp);
 399                 xfs_buf_relse(bp);
 400         }
 401         return error;
 402 }
 403
 404 #define XFS_bdstrat(bp) xfs_buf_iorequest(bp)
 405
 406 #define xfs_iowait(bp)  xfs_buf_iowait(bp)
 407
 408 #define xfs_baread(target, rablkno, ralen)  \
 409         xfs_buf_readahead((target), (rablkno), (ralen), XBF_DONT_BLOCK)
 410
 411
 412 /*
 413  *      Handling of buftargs.
 414  */
 415 extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
 416 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
 417 extern void xfs_wait_buftarg(xfs_buftarg_t *);
 418 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
 419 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
 420 #ifdef CONFIG_KDB_MODULES
 421 extern struct list_head *xfs_get_buftarg_list(void);
 422 #endif
 423
 424 #define xfs_getsize_buftarg(buftarg)    block_size((buftarg)->bt_bdev)
 425 #define xfs_readonly_buftarg(buftarg)   bdev_read_only((buftarg)->bt_bdev)
 426
 427 #define xfs_binval(buftarg)             xfs_flush_buftarg(buftarg, 1)
 428 #define XFS_bflush(buftarg)             xfs_flush_buftarg(buftarg, 1)
 429
 430 #endif  /* __XFS_BUF_H__ */