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 #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_MAPPED      (1 << 2) /* 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 #define XBF_ORDERED     (1 << 11)/* use ordered writes */
  55 #define XBF_READ_AHEAD  (1 << 12)/* asynchronous read-ahead */
  56 #define XBF_LOG_BUFFER  (1 << 13)/* this is a buffer used for the log */
  57
  58 /* flags used only as arguments to access routines */
  59 #define XBF_LOCK        (1 << 14)/* lock requested */
  60 #define XBF_TRYLOCK     (1 << 15)/* lock requested, but do not wait */
  61 #define XBF_DONT_BLOCK  (1 << 16)/* do not block in current thread */
  62
  63 /* flags used only internally */
  64 #define _XBF_PAGES      (1 << 18)/* backed by refcounted pages */
  65 #define _XBF_RUN_QUEUES (1 << 19)/* run block device task queue */
  66 #define _XBF_KMEM       (1 << 20)/* backed by heap memory */
  67 #define _XBF_DELWRI_Q   (1 << 21)/* buffer on delwri queue */
  68
  69 typedef unsigned int xfs_buf_flags_t;
  70
  71 #define XFS_BUF_FLAGS \
  72         { XBF_READ,             "READ" }, \
  73         { XBF_WRITE,            "WRITE" }, \
  74         { XBF_MAPPED,           "MAPPED" }, \
  75         { XBF_ASYNC,            "ASYNC" }, \
  76         { XBF_DONE,             "DONE" }, \
  77         { XBF_DELWRI,           "DELWRI" }, \
  78         { XBF_STALE,            "STALE" }, \
  79         { XBF_ORDERED,          "ORDERED" }, \
  80         { XBF_READ_AHEAD,       "READ_AHEAD" }, \
  81         { XBF_LOCK,             "LOCK" },       /* should never be set */\
  82         { XBF_TRYLOCK,          "TRYLOCK" },    /* ditto */\
  83         { XBF_DONT_BLOCK,       "DONT_BLOCK" }, /* ditto */\
  84         { _XBF_PAGES,           "PAGES" }, \
  85         { _XBF_RUN_QUEUES,      "RUN_QUEUES" }, \
  86         { _XBF_KMEM,            "KMEM" }, \
  87         { _XBF_DELWRI_Q,        "DELWRI_Q" }
  88
  89 typedef enum {
  90         XBT_FORCE_SLEEP = 0,
  91         XBT_FORCE_FLUSH = 1,
  92 } xfs_buftarg_flags_t;
  93
  94 typedef struct xfs_buftarg {
  95         dev_t                   bt_dev;
  96         struct block_device     *bt_bdev;
  97         struct backing_dev_info *bt_bdi;
  98         struct xfs_mount        *bt_mount;
  99         unsigned int            bt_bsize;
 100         unsigned int            bt_sshift;
 101         size_t                  bt_smask;
 102
 103         /* per device delwri queue */
 104         struct task_struct      *bt_task;
 105         struct list_head        bt_delwrite_queue;
 106         spinlock_t              bt_delwrite_lock;
 107         unsigned long           bt_flags;
 108
 109         /* LRU control structures */
 110         struct shrinker         bt_shrinker;
 111         struct list_head        bt_lru;
 112         spinlock_t              bt_lru_lock;
 113         unsigned int            bt_lru_nr;
 114 } xfs_buftarg_t;
 115
 116 struct xfs_buf;
 117 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
 118
 119 #define XB_PAGES        2
 120
 121 typedef struct xfs_buf {
 122         /*
 123          * first cacheline holds all the fields needed for an uncontended cache
 124          * hit to be fully processed. The semaphore straddles the cacheline
 125          * boundary, but the counter and lock sits on the first cacheline,
 126          * which is the only bit that is touched if we hit the semaphore
 127          * fast-path on locking.
 128          */
 129         struct rb_node          b_rbnode;       /* rbtree node */
 130         xfs_off_t               b_file_offset;  /* offset in file */
 131         size_t                  b_buffer_length;/* size of buffer in bytes */
 132         atomic_t                b_hold;         /* reference count */
 133         atomic_t                b_lru_ref;      /* lru reclaim ref count */
 134         xfs_buf_flags_t         b_flags;        /* status flags */
 135         struct semaphore        b_sema;         /* semaphore for lockables */
 136
 137         struct list_head        b_lru;          /* lru list */
 138         wait_queue_head_t       b_waiters;      /* unpin waiters */
 139         struct list_head        b_list;
 140         struct xfs_perag        *b_pag;         /* contains rbtree root */
 141         xfs_buftarg_t           *b_target;      /* buffer target (device) */
 142         xfs_daddr_t             b_bn;           /* block number for I/O */
 143         size_t                  b_count_desired;/* desired transfer size */
 144         void                    *b_addr;        /* virtual address of buffer */
 145         struct work_struct      b_iodone_work;
 146         xfs_buf_iodone_t        b_iodone;       /* I/O completion function */
 147         struct completion       b_iowait;       /* queue for I/O waiters */
 148         void                    *b_fspriv;
 149         void                    *b_fspriv2;
 150         struct page             **b_pages;      /* array of page pointers */
 151         struct page             *b_page_array[XB_PAGES]; /* inline pages */
 152         unsigned long           b_queuetime;    /* time buffer was queued */
 153         atomic_t                b_pin_count;    /* pin count */
 154         atomic_t                b_io_remaining; /* #outstanding I/O requests */
 155         unsigned int            b_page_count;   /* size of page array */
 156         unsigned int            b_offset;       /* page offset in first page */
 157         unsigned short          b_error;        /* error code on I/O */
 158 #ifdef XFS_BUF_LOCK_TRACKING
 159         int                     b_last_holder;
 160 #endif
 161 } xfs_buf_t;
 162
 163
 164 /* Finding and Reading Buffers */
 165 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
 166                                 xfs_buf_flags_t, xfs_buf_t *);
 167 #define xfs_incore(buftarg,blkno,len,lockit) \
 168         _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
 169
 170 extern xfs_buf_t *xfs_buf_get(xfs_buftarg_t *, xfs_off_t, size_t,
 171                                 xfs_buf_flags_t);
 172 extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t,
 173                                 xfs_buf_flags_t);
 174
 175 extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
 176 extern void xfs_buf_set_empty(struct xfs_buf *bp, size_t len);
 177 extern xfs_buf_t *xfs_buf_get_uncached(struct xfs_buftarg *, size_t, int);
 178 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
 179 extern void xfs_buf_hold(xfs_buf_t *);
 180 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t);
 181 struct xfs_buf *xfs_buf_read_uncached(struct xfs_mount *mp,
 182                                 struct xfs_buftarg *target,
 183                                 xfs_daddr_t daddr, size_t length, int flags);
 184
 185 /* Releasing Buffers */
 186 extern void xfs_buf_free(xfs_buf_t *);
 187 extern void xfs_buf_rele(xfs_buf_t *);
 188
 189 /* Locking and Unlocking Buffers */
 190 extern int xfs_buf_trylock(xfs_buf_t *);
 191 extern void xfs_buf_lock(xfs_buf_t *);
 192 extern void xfs_buf_unlock(xfs_buf_t *);
 193 #define xfs_buf_islocked(bp) \
 194         ((bp)->b_sema.count <= 0)
 195
 196 /* Buffer Read and Write Routines */
 197 extern int xfs_bwrite(struct xfs_mount *mp, struct xfs_buf *bp);
 198 extern void xfs_bdwrite(void *mp, xfs_buf_t *bp);
 199
 200 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
 201 extern int xfs_bdstrat_cb(struct xfs_buf *);
 202
 203 extern void xfs_buf_ioend(xfs_buf_t *,  int);
 204 extern void xfs_buf_ioerror(xfs_buf_t *, int);
 205 extern int xfs_buf_iorequest(xfs_buf_t *);
 206 extern int xfs_buf_iowait(xfs_buf_t *);
 207 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
 208                                 xfs_buf_rw_t);
 209 #define xfs_buf_zero(bp, off, len) \
 210             xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
 211
 212 static inline int xfs_buf_geterror(xfs_buf_t *bp)
 213 {
 214         return bp ? bp->b_error : ENOMEM;
 215 }
 216
 217 /* Buffer Utility Routines */
 218 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
 219
 220 /* Delayed Write Buffer Routines */
 221 extern void xfs_buf_delwri_dequeue(xfs_buf_t *);
 222 extern void xfs_buf_delwri_promote(xfs_buf_t *);
 223
 224 /* Buffer Daemon Setup Routines */
 225 extern int xfs_buf_init(void);
 226 extern void xfs_buf_terminate(void);
 227
 228 #define xfs_buf_target_name(target)     \
 229         ({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })
 230
 231
 232 #define XFS_BUF_BFLAGS(bp)      ((bp)->b_flags)
 233 #define XFS_BUF_ZEROFLAGS(bp)   ((bp)->b_flags &= \
 234                 ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI|XBF_ORDERED))
 235
 236 void xfs_buf_stale(struct xfs_buf *bp);
 237 #define XFS_BUF_STALE(bp)       xfs_buf_stale(bp);
 238 #define XFS_BUF_UNSTALE(bp)     ((bp)->b_flags &= ~XBF_STALE)
 239 #define XFS_BUF_ISSTALE(bp)     ((bp)->b_flags & XBF_STALE)
 240 #define XFS_BUF_SUPER_STALE(bp) do {                            \
 241                                         XFS_BUF_STALE(bp);      \
 242                                         xfs_buf_delwri_dequeue(bp);     \
 243                                         XFS_BUF_DONE(bp);       \
 244                                 } while (0)
 245
 246 #define XFS_BUF_DELAYWRITE(bp)          ((bp)->b_flags |= XBF_DELWRI)
 247 #define XFS_BUF_UNDELAYWRITE(bp)        xfs_buf_delwri_dequeue(bp)
 248 #define XFS_BUF_ISDELAYWRITE(bp)        ((bp)->b_flags & XBF_DELWRI)
 249
 250 #define XFS_BUF_ERROR(bp,no)    xfs_buf_ioerror(bp,no)
 251 #define XFS_BUF_GETERROR(bp)    xfs_buf_geterror(bp)
 252 #define XFS_BUF_ISERROR(bp)     (xfs_buf_geterror(bp) ? 1 : 0)
 253
 254 #define XFS_BUF_DONE(bp)        ((bp)->b_flags |= XBF_DONE)
 255 #define XFS_BUF_UNDONE(bp)      ((bp)->b_flags &= ~XBF_DONE)
 256 #define XFS_BUF_ISDONE(bp)      ((bp)->b_flags & XBF_DONE)
 257
 258 #define XFS_BUF_BUSY(bp)        do { } while (0)
 259 #define XFS_BUF_UNBUSY(bp)      do { } while (0)
 260 #define XFS_BUF_ISBUSY(bp)      (1)
 261
 262 #define XFS_BUF_ASYNC(bp)       ((bp)->b_flags |= XBF_ASYNC)
 263 #define XFS_BUF_UNASYNC(bp)     ((bp)->b_flags &= ~XBF_ASYNC)
 264 #define XFS_BUF_ISASYNC(bp)     ((bp)->b_flags & XBF_ASYNC)
 265
 266 #define XFS_BUF_ORDERED(bp)     ((bp)->b_flags |= XBF_ORDERED)
 267 #define XFS_BUF_UNORDERED(bp)   ((bp)->b_flags &= ~XBF_ORDERED)
 268 #define XFS_BUF_ISORDERED(bp)   ((bp)->b_flags & XBF_ORDERED)
 269
 270 #define XFS_BUF_HOLD(bp)        xfs_buf_hold(bp)
 271 #define XFS_BUF_READ(bp)        ((bp)->b_flags |= XBF_READ)
 272 #define XFS_BUF_UNREAD(bp)      ((bp)->b_flags &= ~XBF_READ)
 273 #define XFS_BUF_ISREAD(bp)      ((bp)->b_flags & XBF_READ)
 274
 275 #define XFS_BUF_WRITE(bp)       ((bp)->b_flags |= XBF_WRITE)
 276 #define XFS_BUF_UNWRITE(bp)     ((bp)->b_flags &= ~XBF_WRITE)
 277 #define XFS_BUF_ISWRITE(bp)     ((bp)->b_flags & XBF_WRITE)
 278
 279 #define XFS_BUF_IODONE_FUNC(bp)                 ((bp)->b_iodone)
 280 #define XFS_BUF_SET_IODONE_FUNC(bp, func)       ((bp)->b_iodone = (func))
 281 #define XFS_BUF_CLR_IODONE_FUNC(bp)             ((bp)->b_iodone = NULL)
 282
 283 #define XFS_BUF_FSPRIVATE(bp, type)             ((type)(bp)->b_fspriv)
 284 #define XFS_BUF_SET_FSPRIVATE(bp, val)          ((bp)->b_fspriv = (void*)(val))
 285 #define XFS_BUF_FSPRIVATE2(bp, type)            ((type)(bp)->b_fspriv2)
 286 #define XFS_BUF_SET_FSPRIVATE2(bp, val)         ((bp)->b_fspriv2 = (void*)(val))
 287 #define XFS_BUF_SET_START(bp)                   do { } while (0)
 288
 289 #define XFS_BUF_PTR(bp)                 (xfs_caddr_t)((bp)->b_addr)
 290 #define XFS_BUF_SET_PTR(bp, val, cnt)   xfs_buf_associate_memory(bp, val, cnt)
 291 #define XFS_BUF_ADDR(bp)                ((bp)->b_bn)
 292 #define XFS_BUF_SET_ADDR(bp, bno)       ((bp)->b_bn = (xfs_daddr_t)(bno))
 293 #define XFS_BUF_OFFSET(bp)              ((bp)->b_file_offset)
 294 #define XFS_BUF_SET_OFFSET(bp, off)     ((bp)->b_file_offset = (off))
 295 #define XFS_BUF_COUNT(bp)               ((bp)->b_count_desired)
 296 #define XFS_BUF_SET_COUNT(bp, cnt)      ((bp)->b_count_desired = (cnt))
 297 #define XFS_BUF_SIZE(bp)                ((bp)->b_buffer_length)
 298 #define XFS_BUF_SET_SIZE(bp, cnt)       ((bp)->b_buffer_length = (cnt))
 299
 300 static inline void
 301 xfs_buf_set_ref(
 302         struct xfs_buf  *bp,
 303         int             lru_ref)
 304 {
 305         atomic_set(&bp->b_lru_ref, lru_ref);
 306 }
 307 #define XFS_BUF_SET_VTYPE_REF(bp, type, ref)    xfs_buf_set_ref(bp, ref)
 308 #define XFS_BUF_SET_VTYPE(bp, type)             do { } while (0)
 309
 310 #define XFS_BUF_ISPINNED(bp)    atomic_read(&((bp)->b_pin_count))
 311
 312 #define XFS_BUF_FINISH_IOWAIT(bp)       complete(&bp->b_iowait);
 313
 314 #define XFS_BUF_SET_TARGET(bp, target)  ((bp)->b_target = (target))
 315 #define XFS_BUF_TARGET(bp)              ((bp)->b_target)
 316 #define XFS_BUFTARG_NAME(target)        xfs_buf_target_name(target)
 317
 318 static inline void xfs_buf_relse(xfs_buf_t *bp)
 319 {
 320         xfs_buf_unlock(bp);
 321         xfs_buf_rele(bp);
 322 }
 323
 324 /*
 325  *      Handling of buftargs.
 326  */
 327 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
 328                         struct block_device *, int, const char *);
 329 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
 330 extern void xfs_wait_buftarg(xfs_buftarg_t *);
 331 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
 332 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
 333
 334 #ifdef CONFIG_KDB_MODULES
 335 extern struct list_head *xfs_get_buftarg_list(void);
 336 #endif
 337
 338 #define xfs_getsize_buftarg(buftarg)    block_size((buftarg)->bt_bdev)
 339 #define xfs_readonly_buftarg(buftarg)   bdev_read_only((buftarg)->bt_bdev)
 340
 341 #define xfs_binval(buftarg)             xfs_flush_buftarg(buftarg, 1)
 342 #define XFS_bflush(buftarg)             xfs_flush_buftarg(buftarg, 1)
 343
 344 #endif  /* __XFS_BUF_H__ */