fs/xfs/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_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__ */