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/dax.h>
27 #include <linux/buffer_head.h>
28 #include <linux/uio.h>
29 #include <linux/list_lru.h>
30
31 /*
32 * Base types
33 */
34
35 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
36
37 typedef enum {
38 XBRW_READ = 1, /* transfer into target memory */
39 XBRW_WRITE = 2, /* transfer from target memory */
40 XBRW_ZERO = 3, /* Zero target memory */
41 } xfs_buf_rw_t;
42
43 #define XBF_READ (1 << 0) /* buffer intended for reading from device */
44 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
45 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
46 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
47 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
48 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
49 #define XBF_WRITE_FAIL (1 << 24)/* async writes have failed on this buffer */
50
51 /* I/O hints for the BIO layer */
52 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
53 #define XBF_FUA (1 << 11)/* force cache write through mode */
54 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
55
56 /* flags used only as arguments to access routines */
57 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
58 #define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
59
60 /* flags used only internally */
61 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
62 #define _XBF_KMEM (1 << 21)/* backed by heap memory */
63 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
64 #define _XBF_COMPOUND (1 << 23)/* compound buffer */
65
66 typedef unsigned int xfs_buf_flags_t;
67
68 #define XFS_BUF_FLAGS \
69 { XBF_READ, "READ" }, \
70 { XBF_WRITE, "WRITE" }, \
71 { XBF_READ_AHEAD, "READ_AHEAD" }, \
72 { XBF_ASYNC, "ASYNC" }, \
73 { XBF_DONE, "DONE" }, \
74 { XBF_STALE, "STALE" }, \
75 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \
76 { XBF_SYNCIO, "SYNCIO" }, \
77 { XBF_FUA, "FUA" }, \
78 { XBF_FLUSH, "FLUSH" }, \
79 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
80 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
81 { _XBF_PAGES, "PAGES" }, \
82 { _XBF_KMEM, "KMEM" }, \
83 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
84 { _XBF_COMPOUND, "COMPOUND" }
85
86
87 /*
88 * Internal state flags.
89 */
90 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
91
92 /*
93 * The xfs_buftarg contains 2 notions of "sector size" -
94 *
95 * 1) The metadata sector size, which is the minimum unit and
96 * alignment of IO which will be performed by metadata operations.
97 * 2) The device logical sector size
98 *
99 * The first is specified at mkfs time, and is stored on-disk in the
100 * superblock's sb_sectsize.
101 *
102 * The latter is derived from the underlying device, and controls direct IO
103 * alignment constraints.
104 */
105 typedef struct xfs_buftarg {
106 dev_t bt_dev;
107 struct block_device *bt_bdev;
108 struct backing_dev_info *bt_bdi;
109 struct xfs_mount *bt_mount;
110 unsigned int bt_meta_sectorsize;
111 size_t bt_meta_sectormask;
112 size_t bt_logical_sectorsize;
113 size_t bt_logical_sectormask;
114
115 /* LRU control structures */
116 struct shrinker bt_shrinker;
117 struct list_lru bt_lru;
118 } xfs_buftarg_t;
119
120 struct xfs_buf;
121 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
122
123
124 #define XB_PAGES 2
125
126 struct xfs_buf_map {
127 xfs_daddr_t bm_bn; /* block number for I/O */
128 int bm_len; /* size of I/O */
129 };
130
131 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
132 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
133
134 struct xfs_buf_ops {
135 char *name;
136 void (*verify_read)(struct xfs_buf *);
137 void (*verify_write)(struct xfs_buf *);
138 };
139
140 typedef struct xfs_buf {
141 /*
142 * first cacheline holds all the fields needed for an uncontended cache
143 * hit to be fully processed. The semaphore straddles the cacheline
144 * boundary, but the counter and lock sits on the first cacheline,
145 * which is the only bit that is touched if we hit the semaphore
146 * fast-path on locking.
147 */
148 struct rb_node b_rbnode; /* rbtree node */
149 xfs_daddr_t b_bn; /* block number of buffer */
150 int b_length; /* size of buffer in BBs */
151 atomic_t b_hold; /* reference count */
152 atomic_t b_lru_ref; /* lru reclaim ref count */
153 xfs_buf_flags_t b_flags; /* status flags */
154 struct semaphore b_sema; /* semaphore for lockables */
155
156 /*
157 * concurrent access to b_lru and b_lru_flags are protected by
158 * bt_lru_lock and not by b_sema
159 */
160 struct list_head b_lru; /* lru list */
161 spinlock_t b_lock; /* internal state lock */
162 unsigned int b_state; /* internal state flags */
163 int b_io_error; /* internal IO error state */
164 wait_queue_head_t b_waiters; /* unpin waiters */
165 struct list_head b_list;
166 struct xfs_perag *b_pag; /* contains rbtree root */
167 xfs_buftarg_t *b_target; /* buffer target (device) */
168 void *b_addr; /* virtual address of buffer */
169 struct work_struct b_ioend_work;
170 struct workqueue_struct *b_ioend_wq; /* I/O completion wq */
171 xfs_buf_iodone_t b_iodone; /* I/O completion function */
172 struct completion b_iowait; /* queue for I/O waiters */
173 void *b_fspriv;
174 struct xfs_trans *b_transp;
175 struct page **b_pages; /* array of page pointers */
176 struct page *b_page_array[XB_PAGES]; /* inline pages */
177 struct xfs_buf_map *b_maps; /* compound buffer map */
178 struct xfs_buf_map __b_map; /* inline compound buffer map */
179 int b_map_count;
180 int b_io_length; /* IO size in BBs */
181 atomic_t b_pin_count; /* pin count */
182 atomic_t b_io_remaining; /* #outstanding I/O requests */
183 unsigned int b_page_count; /* size of page array */
184 unsigned int b_offset; /* page offset in first page */
185 int b_error; /* error code on I/O */
186 const struct xfs_buf_ops *b_ops;
187
188 #ifdef XFS_BUF_LOCK_TRACKING
189 int b_last_holder;
190 #endif
191 } xfs_buf_t;
192
193 /* Finding and Reading Buffers */
194 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
195 struct xfs_buf_map *map, int nmaps,
196 xfs_buf_flags_t flags, struct xfs_buf *new_bp);
197
198 static inline struct xfs_buf *
xfs_incore(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags)199 xfs_incore(
200 struct xfs_buftarg *target,
201 xfs_daddr_t blkno,
202 size_t numblks,
203 xfs_buf_flags_t flags)
204 {
205 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
206 return _xfs_buf_find(target, &map, 1, flags, NULL);
207 }
208
209 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
210 struct xfs_buf_map *map, int nmaps,
211 xfs_buf_flags_t flags);
212
213 static inline struct xfs_buf *
xfs_buf_alloc(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags)214 xfs_buf_alloc(
215 struct xfs_buftarg *target,
216 xfs_daddr_t blkno,
217 size_t numblks,
218 xfs_buf_flags_t flags)
219 {
220 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
221 return _xfs_buf_alloc(target, &map, 1, flags);
222 }
223
224 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
225 struct xfs_buf_map *map, int nmaps,
226 xfs_buf_flags_t flags);
227 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
228 struct xfs_buf_map *map, int nmaps,
229 xfs_buf_flags_t flags,
230 const struct xfs_buf_ops *ops);
231 void xfs_buf_readahead_map(struct xfs_buftarg *target,
232 struct xfs_buf_map *map, int nmaps,
233 const struct xfs_buf_ops *ops);
234
235 static inline struct xfs_buf *
xfs_buf_get(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags)236 xfs_buf_get(
237 struct xfs_buftarg *target,
238 xfs_daddr_t blkno,
239 size_t numblks,
240 xfs_buf_flags_t flags)
241 {
242 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
243 return xfs_buf_get_map(target, &map, 1, flags);
244 }
245
246 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)247 xfs_buf_read(
248 struct xfs_buftarg *target,
249 xfs_daddr_t blkno,
250 size_t numblks,
251 xfs_buf_flags_t flags,
252 const struct xfs_buf_ops *ops)
253 {
254 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
255 return xfs_buf_read_map(target, &map, 1, flags, ops);
256 }
257
258 static inline void
xfs_buf_readahead(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,const struct xfs_buf_ops * ops)259 xfs_buf_readahead(
260 struct xfs_buftarg *target,
261 xfs_daddr_t blkno,
262 size_t numblks,
263 const struct xfs_buf_ops *ops)
264 {
265 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
266 return xfs_buf_readahead_map(target, &map, 1, ops);
267 }
268
269 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
270 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
271 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
272
273 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
274 int flags);
275 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
276 size_t numblks, int flags, struct xfs_buf **bpp,
277 const struct xfs_buf_ops *ops);
278 void xfs_buf_hold(struct xfs_buf *bp);
279
280 /* Releasing Buffers */
281 extern void xfs_buf_free(xfs_buf_t *);
282 extern void xfs_buf_rele(xfs_buf_t *);
283
284 /* Locking and Unlocking Buffers */
285 extern int xfs_buf_trylock(xfs_buf_t *);
286 extern void xfs_buf_lock(xfs_buf_t *);
287 extern void xfs_buf_unlock(xfs_buf_t *);
288 #define xfs_buf_islocked(bp) \
289 ((bp)->b_sema.count <= 0)
290
291 /* Buffer Read and Write Routines */
292 extern int xfs_bwrite(struct xfs_buf *bp);
293 extern void xfs_buf_ioend(struct xfs_buf *bp);
294 extern void xfs_buf_ioerror(xfs_buf_t *, int);
295 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
296 extern void xfs_buf_submit(struct xfs_buf *bp);
297 extern int xfs_buf_submit_wait(struct xfs_buf *bp);
298 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
299 xfs_buf_rw_t);
300 #define xfs_buf_zero(bp, off, len) \
301 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
302
303 /* Buffer Utility Routines */
304 extern void *xfs_buf_offset(struct xfs_buf *, size_t);
305
306 /* Delayed Write Buffer Routines */
307 extern void xfs_buf_delwri_cancel(struct list_head *);
308 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
309 extern int xfs_buf_delwri_submit(struct list_head *);
310 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
311
312 /* Buffer Daemon Setup Routines */
313 extern int xfs_buf_init(void);
314 extern void xfs_buf_terminate(void);
315
316 #define XFS_BUF_ZEROFLAGS(bp) \
317 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
318 XBF_SYNCIO|XBF_FUA|XBF_FLUSH| \
319 XBF_WRITE_FAIL))
320
321 void xfs_buf_stale(struct xfs_buf *bp);
322 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
323 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
324
325 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
326 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
327 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
328
329 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
330 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
331 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
332
333 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
334 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
335 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
336
337 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
338 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
339 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
340
341 /*
342 * These macros use the IO block map rather than b_bn. b_bn is now really
343 * just for the buffer cache index for cached buffers. As IO does not use b_bn
344 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO
345 * map directly. Uncached buffers are not allowed to be discontiguous, so this
346 * is safe to do.
347 *
348 * In future, uncached buffers will pass the block number directly to the io
349 * request function and hence these macros will go away at that point.
350 */
351 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn)
352 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
353
xfs_buf_set_ref(struct xfs_buf * bp,int lru_ref)354 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
355 {
356 atomic_set(&bp->b_lru_ref, lru_ref);
357 }
358
xfs_buf_ispinned(struct xfs_buf * bp)359 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
360 {
361 return atomic_read(&bp->b_pin_count);
362 }
363
xfs_buf_relse(xfs_buf_t * bp)364 static inline void xfs_buf_relse(xfs_buf_t *bp)
365 {
366 xfs_buf_unlock(bp);
367 xfs_buf_rele(bp);
368 }
369
370 static inline int
xfs_buf_verify_cksum(struct xfs_buf * bp,unsigned long cksum_offset)371 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
372 {
373 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
374 cksum_offset);
375 }
376
377 static inline void
xfs_buf_update_cksum(struct xfs_buf * bp,unsigned long cksum_offset)378 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
379 {
380 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
381 cksum_offset);
382 }
383
384 /*
385 * Handling of buftargs.
386 */
387 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
388 struct block_device *);
389 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
390 extern void xfs_wait_buftarg(xfs_buftarg_t *);
391 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int);
392
393 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
394 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
395
396 #endif /* __XFS_BUF_H__ */
397