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 #include <linux/list_lru.h>
29
30 /*
31 * Base types
32 */
33
34 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
35
36 typedef enum {
37 XBRW_READ = 1, /* transfer into target memory */
38 XBRW_WRITE = 2, /* transfer from target memory */
39 XBRW_ZERO = 3, /* Zero target memory */
40 } xfs_buf_rw_t;
41
42 #define XBF_READ (1 << 0) /* buffer intended for reading from device */
43 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
44 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
45 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
46 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
47 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
48 #define XBF_WRITE_FAIL (1 << 24)/* async writes have failed on this buffer */
49
50 /* I/O hints for the BIO layer */
51 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
52 #define XBF_FUA (1 << 11)/* force cache write through mode */
53 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
54
55 /* flags used only as arguments to access routines */
56 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
57 #define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
58
59 /* flags used only internally */
60 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
61 #define _XBF_KMEM (1 << 21)/* backed by heap memory */
62 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
63 #define _XBF_COMPOUND (1 << 23)/* compound buffer */
64
65 typedef unsigned int xfs_buf_flags_t;
66
67 #define XFS_BUF_FLAGS \
68 { XBF_READ, "READ" }, \
69 { XBF_WRITE, "WRITE" }, \
70 { XBF_READ_AHEAD, "READ_AHEAD" }, \
71 { XBF_ASYNC, "ASYNC" }, \
72 { XBF_DONE, "DONE" }, \
73 { XBF_STALE, "STALE" }, \
74 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \
75 { XBF_SYNCIO, "SYNCIO" }, \
76 { XBF_FUA, "FUA" }, \
77 { XBF_FLUSH, "FLUSH" }, \
78 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
79 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
80 { _XBF_PAGES, "PAGES" }, \
81 { _XBF_KMEM, "KMEM" }, \
82 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
83 { _XBF_COMPOUND, "COMPOUND" }
84
85
86 /*
87 * Internal state flags.
88 */
89 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
90
91 /*
92 * The xfs_buftarg contains 2 notions of "sector size" -
93 *
94 * 1) The metadata sector size, which is the minimum unit and
95 * alignment of IO which will be performed by metadata operations.
96 * 2) The device logical sector size
97 *
98 * The first is specified at mkfs time, and is stored on-disk in the
99 * superblock's sb_sectsize.
100 *
101 * The latter is derived from the underlying device, and controls direct IO
102 * alignment constraints.
103 */
104 typedef struct xfs_buftarg {
105 dev_t bt_dev;
106 struct block_device *bt_bdev;
107 struct backing_dev_info *bt_bdi;
108 struct xfs_mount *bt_mount;
109 unsigned int bt_meta_sectorsize;
110 size_t bt_meta_sectormask;
111 size_t bt_logical_sectorsize;
112 size_t bt_logical_sectormask;
113
114 /* LRU control structures */
115 struct shrinker bt_shrinker;
116 struct list_lru bt_lru;
117 } xfs_buftarg_t;
118
119 struct xfs_buf;
120 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
121
122
123 #define XB_PAGES 2
124
125 struct xfs_buf_map {
126 xfs_daddr_t bm_bn; /* block number for I/O */
127 int bm_len; /* size of I/O */
128 };
129
130 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
131 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
132
133 struct xfs_buf_ops {
134 char *name;
135 void (*verify_read)(struct xfs_buf *);
136 void (*verify_write)(struct xfs_buf *);
137 };
138
139 typedef struct xfs_buf {
140 /*
141 * first cacheline holds all the fields needed for an uncontended cache
142 * hit to be fully processed. The semaphore straddles the cacheline
143 * boundary, but the counter and lock sits on the first cacheline,
144 * which is the only bit that is touched if we hit the semaphore
145 * fast-path on locking.
146 */
147 struct rb_node b_rbnode; /* rbtree node */
148 xfs_daddr_t b_bn; /* block number of buffer */
149 int b_length; /* size of buffer in BBs */
150 atomic_t b_hold; /* reference count */
151 atomic_t b_lru_ref; /* lru reclaim ref count */
152 xfs_buf_flags_t b_flags; /* status flags */
153 struct semaphore b_sema; /* semaphore for lockables */
154
155 /*
156 * concurrent access to b_lru and b_lru_flags are protected by
157 * bt_lru_lock and not by b_sema
158 */
159 struct list_head b_lru; /* lru list */
160 spinlock_t b_lock; /* internal state lock */
161 unsigned int b_state; /* internal state flags */
162 int b_io_error; /* internal IO error state */
163 wait_queue_head_t b_waiters; /* unpin waiters */
164 struct list_head b_list;
165 struct xfs_perag *b_pag; /* contains rbtree root */
166 xfs_buftarg_t *b_target; /* buffer target (device) */
167 void *b_addr; /* virtual address of buffer */
168 struct work_struct b_iodone_work;
169 xfs_buf_iodone_t b_iodone; /* I/O completion function */
170 struct completion b_iowait; /* queue for I/O waiters */
171 void *b_fspriv;
172 struct xfs_trans *b_transp;
173 struct page **b_pages; /* array of page pointers */
174 struct page *b_page_array[XB_PAGES]; /* inline pages */
175 struct xfs_buf_map *b_maps; /* compound buffer map */
176 struct xfs_buf_map __b_map; /* inline compound buffer map */
177 int b_map_count;
178 int b_io_length; /* IO size in BBs */
179 atomic_t b_pin_count; /* pin count */
180 atomic_t b_io_remaining; /* #outstanding I/O requests */
181 unsigned int b_page_count; /* size of page array */
182 unsigned int b_offset; /* page offset in first page */
183 int b_error; /* error code on I/O */
184 const struct xfs_buf_ops *b_ops;
185
186 #ifdef XFS_BUF_LOCK_TRACKING
187 int b_last_holder;
188 #endif
189 } xfs_buf_t;
190
191 /* Finding and Reading Buffers */
192 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
193 struct xfs_buf_map *map, int nmaps,
194 xfs_buf_flags_t flags, struct xfs_buf *new_bp);
195
196 static inline struct xfs_buf *
xfs_incore(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags)197 xfs_incore(
198 struct xfs_buftarg *target,
199 xfs_daddr_t blkno,
200 size_t numblks,
201 xfs_buf_flags_t flags)
202 {
203 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
204 return _xfs_buf_find(target, &map, 1, flags, NULL);
205 }
206
207 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
208 struct xfs_buf_map *map, int nmaps,
209 xfs_buf_flags_t flags);
210
211 static inline struct xfs_buf *
xfs_buf_alloc(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags)212 xfs_buf_alloc(
213 struct xfs_buftarg *target,
214 xfs_daddr_t blkno,
215 size_t numblks,
216 xfs_buf_flags_t flags)
217 {
218 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
219 return _xfs_buf_alloc(target, &map, 1, flags);
220 }
221
222 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
223 struct xfs_buf_map *map, int nmaps,
224 xfs_buf_flags_t flags);
225 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
226 struct xfs_buf_map *map, int nmaps,
227 xfs_buf_flags_t flags,
228 const struct xfs_buf_ops *ops);
229 void xfs_buf_readahead_map(struct xfs_buftarg *target,
230 struct xfs_buf_map *map, int nmaps,
231 const struct xfs_buf_ops *ops);
232
233 static inline struct xfs_buf *
xfs_buf_get(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags)234 xfs_buf_get(
235 struct xfs_buftarg *target,
236 xfs_daddr_t blkno,
237 size_t numblks,
238 xfs_buf_flags_t flags)
239 {
240 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
241 return xfs_buf_get_map(target, &map, 1, flags);
242 }
243
244 static inline struct xfs_buf *
xfs_buf_read(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags,const struct xfs_buf_ops * ops)245 xfs_buf_read(
246 struct xfs_buftarg *target,
247 xfs_daddr_t blkno,
248 size_t numblks,
249 xfs_buf_flags_t flags,
250 const struct xfs_buf_ops *ops)
251 {
252 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
253 return xfs_buf_read_map(target, &map, 1, flags, ops);
254 }
255
256 static inline void
xfs_buf_readahead(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,const struct xfs_buf_ops * ops)257 xfs_buf_readahead(
258 struct xfs_buftarg *target,
259 xfs_daddr_t blkno,
260 size_t numblks,
261 const struct xfs_buf_ops *ops)
262 {
263 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
264 return xfs_buf_readahead_map(target, &map, 1, ops);
265 }
266
267 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
268 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
269 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
270
271 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
272 int flags);
273 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
274 size_t numblks, int flags, struct xfs_buf **bpp,
275 const struct xfs_buf_ops *ops);
276 void xfs_buf_hold(struct xfs_buf *bp);
277
278 /* Releasing Buffers */
279 extern void xfs_buf_free(xfs_buf_t *);
280 extern void xfs_buf_rele(xfs_buf_t *);
281
282 /* Locking and Unlocking Buffers */
283 extern int xfs_buf_trylock(xfs_buf_t *);
284 extern void xfs_buf_lock(xfs_buf_t *);
285 extern void xfs_buf_unlock(xfs_buf_t *);
286 #define xfs_buf_islocked(bp) \
287 ((bp)->b_sema.count <= 0)
288
289 /* Buffer Read and Write Routines */
290 extern int xfs_bwrite(struct xfs_buf *bp);
291 extern void xfs_buf_ioend(struct xfs_buf *bp);
292 extern void xfs_buf_ioerror(xfs_buf_t *, int);
293 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
294 extern void xfs_buf_submit(struct xfs_buf *bp);
295 extern int xfs_buf_submit_wait(struct xfs_buf *bp);
296 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
297 xfs_buf_rw_t);
298 #define xfs_buf_zero(bp, off, len) \
299 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
300
301 /* Buffer Utility Routines */
302 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
303
304 /* Delayed Write Buffer Routines */
305 extern void xfs_buf_delwri_cancel(struct list_head *);
306 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
307 extern int xfs_buf_delwri_submit(struct list_head *);
308 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
309
310 /* Buffer Daemon Setup Routines */
311 extern int xfs_buf_init(void);
312 extern void xfs_buf_terminate(void);
313
314 #define XFS_BUF_ZEROFLAGS(bp) \
315 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
316 XBF_SYNCIO|XBF_FUA|XBF_FLUSH| \
317 XBF_WRITE_FAIL))
318
319 void xfs_buf_stale(struct xfs_buf *bp);
320 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
321 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
322
323 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
324 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
325 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
326
327 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
328 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
329 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
330
331 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
332 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
333 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
334
335 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
336 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
337 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
338
339 /*
340 * These macros use the IO block map rather than b_bn. b_bn is now really
341 * just for the buffer cache index for cached buffers. As IO does not use b_bn
342 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO
343 * map directly. Uncached buffers are not allowed to be discontiguous, so this
344 * is safe to do.
345 *
346 * In future, uncached buffers will pass the block number directly to the io
347 * request function and hence these macros will go away at that point.
348 */
349 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn)
350 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
351
xfs_buf_set_ref(struct xfs_buf * bp,int lru_ref)352 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
353 {
354 atomic_set(&bp->b_lru_ref, lru_ref);
355 }
356
xfs_buf_ispinned(struct xfs_buf * bp)357 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
358 {
359 return atomic_read(&bp->b_pin_count);
360 }
361
xfs_buf_relse(xfs_buf_t * bp)362 static inline void xfs_buf_relse(xfs_buf_t *bp)
363 {
364 xfs_buf_unlock(bp);
365 xfs_buf_rele(bp);
366 }
367
368 static inline int
xfs_buf_verify_cksum(struct xfs_buf * bp,unsigned long cksum_offset)369 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
370 {
371 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
372 cksum_offset);
373 }
374
375 static inline void
xfs_buf_update_cksum(struct xfs_buf * bp,unsigned long cksum_offset)376 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
377 {
378 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
379 cksum_offset);
380 }
381
382 /*
383 * Handling of buftargs.
384 */
385 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
386 struct block_device *);
387 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
388 extern void xfs_wait_buftarg(xfs_buftarg_t *);
389 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int);
390
391 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
392 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
393
394 #endif /* __XFS_BUF_H__ */
395