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