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_daddr_t b_bn; /* block number for I/O */
120 int b_length; /* size of buffer in BBs */
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 size_t b_count_desired;/* desired transfer size */
132 void *b_addr; /* virtual address of buffer */
133 struct work_struct b_iodone_work;
134 xfs_buf_iodone_t b_iodone; /* I/O completion function */
135 struct completion b_iowait; /* queue for I/O waiters */
137 struct xfs_trans *b_transp;
138 struct page **b_pages; /* array of page pointers */
139 struct page *b_page_array[XB_PAGES]; /* inline pages */
140 atomic_t b_pin_count; /* pin count */
141 atomic_t b_io_remaining; /* #outstanding I/O requests */
142 unsigned int b_page_count; /* size of page array */
143 unsigned int b_offset; /* page offset in first page */
144 unsigned short b_error; /* error code on I/O */
145 #ifdef XFS_BUF_LOCK_TRACKING
151 /* Finding and Reading Buffers */
152 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, xfs_daddr_t blkno,
153 size_t numblks, xfs_buf_flags_t flags,
154 struct xfs_buf *new_bp);
155 #define xfs_incore(buftarg,blkno,len,lockit) \
156 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
158 struct xfs_buf *xfs_buf_get(struct xfs_buftarg *target, xfs_daddr_t blkno,
159 size_t numblks, xfs_buf_flags_t flags);
160 struct xfs_buf *xfs_buf_read(struct xfs_buftarg *target, xfs_daddr_t blkno,
161 size_t numblks, xfs_buf_flags_t flags);
162 void xfs_buf_readahead(struct xfs_buftarg *target, xfs_daddr_t blkno,
165 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
166 struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *target, xfs_daddr_t blkno,
167 size_t numblks, xfs_buf_flags_t flags);
168 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
169 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
171 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
173 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
174 xfs_daddr_t daddr, size_t numblks, int flags);
175 void xfs_buf_hold(struct xfs_buf *bp);
177 /* Releasing Buffers */
178 extern void xfs_buf_free(xfs_buf_t *);
179 extern void xfs_buf_rele(xfs_buf_t *);
181 /* Locking and Unlocking Buffers */
182 extern int xfs_buf_trylock(xfs_buf_t *);
183 extern void xfs_buf_lock(xfs_buf_t *);
184 extern void xfs_buf_unlock(xfs_buf_t *);
185 #define xfs_buf_islocked(bp) \
186 ((bp)->b_sema.count <= 0)
188 /* Buffer Read and Write Routines */
189 extern int xfs_bwrite(struct xfs_buf *bp);
191 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
192 extern int xfs_bdstrat_cb(struct xfs_buf *);
194 extern void xfs_buf_ioend(xfs_buf_t *, int);
195 extern void xfs_buf_ioerror(xfs_buf_t *, int);
196 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
197 extern void xfs_buf_iorequest(xfs_buf_t *);
198 extern int xfs_buf_iowait(xfs_buf_t *);
199 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
201 #define xfs_buf_zero(bp, off, len) \
202 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
204 static inline int xfs_buf_geterror(xfs_buf_t *bp)
206 return bp ? bp->b_error : ENOMEM;
209 /* Buffer Utility Routines */
210 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
212 /* Delayed Write Buffer Routines */
213 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
214 extern int xfs_buf_delwri_submit(struct list_head *);
215 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
217 /* Buffer Daemon Setup Routines */
218 extern int xfs_buf_init(void);
219 extern void xfs_buf_terminate(void);
221 #define XFS_BUF_ZEROFLAGS(bp) \
222 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
223 XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
225 void xfs_buf_stale(struct xfs_buf *bp);
226 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
227 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
229 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
230 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
231 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
233 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
234 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
235 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
237 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
238 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
239 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
241 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
242 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
243 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
245 #define XFS_BUF_ADDR(bp) ((bp)->b_bn)
246 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
247 #define XFS_BUF_COUNT(bp) ((bp)->b_count_desired)
248 #define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt))
250 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
252 atomic_set(&bp->b_lru_ref, lru_ref);
255 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
257 return atomic_read(&bp->b_pin_count);
260 static inline void xfs_buf_relse(xfs_buf_t *bp)
267 * Handling of buftargs.
269 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
270 struct block_device *, int, const char *);
271 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
272 extern void xfs_wait_buftarg(xfs_buftarg_t *);
273 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
275 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
276 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
278 #endif /* __XFS_BUF_H__ */