2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
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.
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.
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
21 #include <linux/list.h>
22 #include <linux/types.h>
23 #include <linux/spinlock.h>
26 #include <linux/buffer_head.h>
27 #include <linux/uio.h>
33 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
35 #define xfs_buf_ctob(pp) ((pp) * PAGE_CACHE_SIZE)
36 #define xfs_buf_btoc(dd) (((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
37 #define xfs_buf_btoct(dd) ((dd) >> PAGE_CACHE_SHIFT)
38 #define xfs_buf_poff(aa) ((aa) & ~PAGE_CACHE_MASK)
41 XBRW_READ = 1, /* transfer into target memory */
42 XBRW_WRITE = 2, /* transfer from target memory */
43 XBRW_ZERO = 3, /* Zero target memory */
46 #define XBF_READ (1 << 0) /* buffer intended for reading from device */
47 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
48 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
49 #define XBF_MAPPED (1 << 3) /* 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_STALE (1 << 6) /* buffer has been staled, do not find it */
54 /* I/O hints for the BIO layer */
55 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
56 #define XBF_FUA (1 << 11)/* force cache write through mode */
57 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
59 /* flags used only as arguments to access routines */
60 #define XBF_LOCK (1 << 15)/* lock requested */
61 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
62 #define XBF_DONT_BLOCK (1 << 17)/* do not block in current thread */
64 /* flags used only internally */
65 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
66 #define _XBF_KMEM (1 << 21)/* backed by heap memory */
67 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
69 typedef unsigned int xfs_buf_flags_t;
71 #define XFS_BUF_FLAGS \
72 { XBF_READ, "READ" }, \
73 { XBF_WRITE, "WRITE" }, \
74 { XBF_READ_AHEAD, "READ_AHEAD" }, \
75 { XBF_MAPPED, "MAPPED" }, \
76 { XBF_ASYNC, "ASYNC" }, \
77 { XBF_DONE, "DONE" }, \
78 { XBF_STALE, "STALE" }, \
79 { XBF_SYNCIO, "SYNCIO" }, \
81 { XBF_FLUSH, "FLUSH" }, \
82 { XBF_LOCK, "LOCK" }, /* should never be set */\
83 { XBF_TRYLOCK, "TRYLOCK" }, /* ditto */\
84 { XBF_DONT_BLOCK, "DONT_BLOCK" }, /* ditto */\
85 { _XBF_PAGES, "PAGES" }, \
86 { _XBF_KMEM, "KMEM" }, \
87 { _XBF_DELWRI_Q, "DELWRI_Q" }
89 typedef struct xfs_buftarg {
91 struct block_device *bt_bdev;
92 struct backing_dev_info *bt_bdi;
93 struct xfs_mount *bt_mount;
94 unsigned int bt_bsize;
95 unsigned int bt_sshift;
98 /* LRU control structures */
99 struct shrinker bt_shrinker;
100 struct list_head bt_lru;
101 spinlock_t bt_lru_lock;
102 unsigned int bt_lru_nr;
106 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
110 typedef struct xfs_buf {
112 * first cacheline holds all the fields needed for an uncontended cache
113 * hit to be fully processed. The semaphore straddles the cacheline
114 * boundary, but the counter and lock sits on the first cacheline,
115 * which is the only bit that is touched if we hit the semaphore
116 * fast-path on locking.
118 struct rb_node b_rbnode; /* rbtree node */
119 xfs_off_t b_file_offset; /* offset in file */
120 size_t b_buffer_length;/* size of buffer in bytes */
121 atomic_t b_hold; /* reference count */
122 atomic_t b_lru_ref; /* lru reclaim ref count */
123 xfs_buf_flags_t b_flags; /* status flags */
124 struct semaphore b_sema; /* semaphore for lockables */
126 struct list_head b_lru; /* lru list */
127 wait_queue_head_t b_waiters; /* unpin waiters */
128 struct list_head b_list;
129 struct xfs_perag *b_pag; /* contains rbtree root */
130 xfs_buftarg_t *b_target; /* buffer target (device) */
131 xfs_daddr_t b_bn; /* block number for I/O */
132 size_t b_count_desired;/* desired transfer size */
133 void *b_addr; /* virtual address of buffer */
134 struct work_struct b_iodone_work;
135 xfs_buf_iodone_t b_iodone; /* I/O completion function */
136 struct completion b_iowait; /* queue for I/O waiters */
138 struct xfs_trans *b_transp;
139 struct page **b_pages; /* array of page pointers */
140 struct page *b_page_array[XB_PAGES]; /* inline pages */
141 atomic_t b_pin_count; /* pin count */
142 atomic_t b_io_remaining; /* #outstanding I/O requests */
143 unsigned int b_page_count; /* size of page array */
144 unsigned int b_offset; /* page offset in first page */
145 unsigned short b_error; /* error code on I/O */
146 #ifdef XFS_BUF_LOCK_TRACKING
152 /* Finding and Reading Buffers */
153 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
154 xfs_buf_flags_t, xfs_buf_t *);
155 #define xfs_incore(buftarg,blkno,len,lockit) \
156 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
158 extern xfs_buf_t *xfs_buf_get(xfs_buftarg_t *, xfs_off_t, size_t,
160 extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t,
163 struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *, xfs_off_t, size_t,
165 extern void xfs_buf_set_empty(struct xfs_buf *bp, size_t len);
166 extern xfs_buf_t *xfs_buf_get_uncached(struct xfs_buftarg *, size_t, int);
167 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
168 extern void xfs_buf_hold(xfs_buf_t *);
169 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t);
170 struct xfs_buf *xfs_buf_read_uncached(struct xfs_mount *mp,
171 struct xfs_buftarg *target,
172 xfs_daddr_t daddr, size_t length, int flags);
174 /* Releasing Buffers */
175 extern void xfs_buf_free(xfs_buf_t *);
176 extern void xfs_buf_rele(xfs_buf_t *);
178 /* Locking and Unlocking Buffers */
179 extern int xfs_buf_trylock(xfs_buf_t *);
180 extern void xfs_buf_lock(xfs_buf_t *);
181 extern void xfs_buf_unlock(xfs_buf_t *);
182 #define xfs_buf_islocked(bp) \
183 ((bp)->b_sema.count <= 0)
185 /* Buffer Read and Write Routines */
186 extern int xfs_bwrite(struct xfs_buf *bp);
188 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
189 extern int xfs_bdstrat_cb(struct xfs_buf *);
191 extern void xfs_buf_ioend(xfs_buf_t *, int);
192 extern void xfs_buf_ioerror(xfs_buf_t *, int);
193 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
194 extern void 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, void *,
198 #define xfs_buf_zero(bp, off, len) \
199 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
201 static inline int xfs_buf_geterror(xfs_buf_t *bp)
203 return bp ? bp->b_error : ENOMEM;
206 /* Buffer Utility Routines */
207 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
209 /* Delayed Write Buffer Routines */
210 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
211 extern int xfs_buf_delwri_submit(struct list_head *);
212 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
214 /* Buffer Daemon Setup Routines */
215 extern int xfs_buf_init(void);
216 extern void xfs_buf_terminate(void);
218 #define XFS_BUF_ZEROFLAGS(bp) \
219 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
220 XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
222 void xfs_buf_stale(struct xfs_buf *bp);
223 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
224 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
226 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
227 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
228 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
230 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
231 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
232 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
234 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
235 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
236 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
238 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
239 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
240 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
242 #define XFS_BUF_ADDR(bp) ((bp)->b_bn)
243 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
244 #define XFS_BUF_OFFSET(bp) ((bp)->b_file_offset)
245 #define XFS_BUF_SET_OFFSET(bp, off) ((bp)->b_file_offset = (off))
246 #define XFS_BUF_COUNT(bp) ((bp)->b_count_desired)
247 #define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt))
248 #define XFS_BUF_SIZE(bp) ((bp)->b_buffer_length)
249 #define XFS_BUF_SET_SIZE(bp, cnt) ((bp)->b_buffer_length = (cnt))
251 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
253 atomic_set(&bp->b_lru_ref, lru_ref);
256 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
258 return atomic_read(&bp->b_pin_count);
261 static inline void xfs_buf_relse(xfs_buf_t *bp)
268 * Handling of buftargs.
270 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
271 struct block_device *, int, const char *);
272 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
273 extern void xfs_wait_buftarg(xfs_buftarg_t *);
274 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
276 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
277 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
279 #endif /* __XFS_BUF_H__ */