1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6 #ifndef __XFS_BUF_H__
7 #define __XFS_BUF_H__
8
9 #include <linux/list.h>
10 #include <linux/types.h>
11 #include <linux/spinlock.h>
12 #include <linux/mm.h>
13 #include <linux/fs.h>
14 #include <linux/dax.h>
15 #include <linux/uio.h>
16 #include <linux/list_lru.h>
17
18 extern struct kmem_cache *xfs_buf_cache;
19
20 /*
21 * Base types
22 */
23 struct xfs_buf;
24
25 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
26
27 #define XBF_READ (1u << 0) /* buffer intended for reading from device */
28 #define XBF_WRITE (1u << 1) /* buffer intended for writing to device */
29 #define XBF_READ_AHEAD (1u << 2) /* asynchronous read-ahead */
30 #define XBF_NO_IOACCT (1u << 3) /* bypass I/O accounting (non-LRU bufs) */
31 #define XBF_ASYNC (1u << 4) /* initiator will not wait for completion */
32 #define XBF_DONE (1u << 5) /* all pages in the buffer uptodate */
33 #define XBF_STALE (1u << 6) /* buffer has been staled, do not find it */
34 #define XBF_WRITE_FAIL (1u << 7) /* async writes have failed on this buffer */
35
36 /* buffer type flags for write callbacks */
37 #define _XBF_INODES (1u << 16)/* inode buffer */
38 #define _XBF_DQUOTS (1u << 17)/* dquot buffer */
39 #define _XBF_LOGRECOVERY (1u << 18)/* log recovery buffer */
40
41 /* flags used only internally */
42 #define _XBF_PAGES (1u << 20)/* backed by refcounted pages */
43 #define _XBF_KMEM (1u << 21)/* backed by heap memory */
44 #define _XBF_DELWRI_Q (1u << 22)/* buffer on a delwri queue */
45
46 /* flags used only as arguments to access routines */
47 /*
48 * Online fsck is scanning the buffer cache for live buffers. Do not warn
49 * about length mismatches during lookups and do not return stale buffers.
50 */
51 #define XBF_LIVESCAN (1u << 28)
52 #define XBF_INCORE (1u << 29)/* lookup only, return if found in cache */
53 #define XBF_TRYLOCK (1u << 30)/* lock requested, but do not wait */
54 #define XBF_UNMAPPED (1u << 31)/* do not map the buffer */
55
56
57 typedef unsigned int xfs_buf_flags_t;
58
59 #define XFS_BUF_FLAGS \
60 { XBF_READ, "READ" }, \
61 { XBF_WRITE, "WRITE" }, \
62 { XBF_READ_AHEAD, "READ_AHEAD" }, \
63 { XBF_NO_IOACCT, "NO_IOACCT" }, \
64 { XBF_ASYNC, "ASYNC" }, \
65 { XBF_DONE, "DONE" }, \
66 { XBF_STALE, "STALE" }, \
67 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \
68 { _XBF_INODES, "INODES" }, \
69 { _XBF_DQUOTS, "DQUOTS" }, \
70 { _XBF_LOGRECOVERY, "LOG_RECOVERY" }, \
71 { _XBF_PAGES, "PAGES" }, \
72 { _XBF_KMEM, "KMEM" }, \
73 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
74 /* The following interface flags should never be set */ \
75 { XBF_LIVESCAN, "LIVESCAN" }, \
76 { XBF_INCORE, "INCORE" }, \
77 { XBF_TRYLOCK, "TRYLOCK" }, \
78 { XBF_UNMAPPED, "UNMAPPED" }
79
80 /*
81 * Internal state flags.
82 */
83 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
84 #define XFS_BSTATE_IN_FLIGHT (1 << 1) /* I/O in flight */
85
86 struct xfs_buf_cache {
87 spinlock_t bc_lock;
88 struct rhashtable bc_hash;
89 };
90
91 int xfs_buf_cache_init(struct xfs_buf_cache *bch);
92 void xfs_buf_cache_destroy(struct xfs_buf_cache *bch);
93
94 /*
95 * The xfs_buftarg contains 2 notions of "sector size" -
96 *
97 * 1) The metadata sector size, which is the minimum unit and
98 * alignment of IO which will be performed by metadata operations.
99 * 2) The device logical sector size
100 *
101 * The first is specified at mkfs time, and is stored on-disk in the
102 * superblock's sb_sectsize.
103 *
104 * The latter is derived from the underlying device, and controls direct IO
105 * alignment constraints.
106 */
107 struct xfs_buftarg {
108 dev_t bt_dev;
109 struct file *bt_bdev_file;
110 struct block_device *bt_bdev;
111 struct dax_device *bt_daxdev;
112 struct file *bt_file;
113 u64 bt_dax_part_off;
114 struct xfs_mount *bt_mount;
115 unsigned int bt_meta_sectorsize;
116 size_t bt_meta_sectormask;
117 size_t bt_logical_sectorsize;
118 size_t bt_logical_sectormask;
119
120 /* LRU control structures */
121 struct shrinker *bt_shrinker;
122 struct list_lru bt_lru;
123
124 struct percpu_counter bt_io_count;
125 struct ratelimit_state bt_ioerror_rl;
126
127 /* built-in cache, if we're not using the perag one */
128 struct xfs_buf_cache bt_cache[];
129 };
130
131 #define XB_PAGES 2
132
133 struct xfs_buf_map {
134 xfs_daddr_t bm_bn; /* block number for I/O */
135 int bm_len; /* size of I/O */
136 unsigned int bm_flags;
137 };
138
139 /*
140 * Online fsck is scanning the buffer cache for live buffers. Do not warn
141 * about length mismatches during lookups and do not return stale buffers.
142 */
143 #define XBM_LIVESCAN (1U << 0)
144
145 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
146 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
147
148 struct xfs_buf_ops {
149 char *name;
150 union {
151 __be32 magic[2]; /* v4 and v5 on disk magic values */
152 __be16 magic16[2]; /* v4 and v5 on disk magic values */
153 };
154 void (*verify_read)(struct xfs_buf *);
155 void (*verify_write)(struct xfs_buf *);
156 xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
157 };
158
159 struct xfs_buf {
160 /*
161 * first cacheline holds all the fields needed for an uncontended cache
162 * hit to be fully processed. The semaphore straddles the cacheline
163 * boundary, but the counter and lock sits on the first cacheline,
164 * which is the only bit that is touched if we hit the semaphore
165 * fast-path on locking.
166 */
167 struct rhash_head b_rhash_head; /* pag buffer hash node */
168
169 xfs_daddr_t b_rhash_key; /* buffer cache index */
170 int b_length; /* size of buffer in BBs */
171 atomic_t b_hold; /* reference count */
172 atomic_t b_lru_ref; /* lru reclaim ref count */
173 xfs_buf_flags_t b_flags; /* status flags */
174 struct semaphore b_sema; /* semaphore for lockables */
175
176 /*
177 * concurrent access to b_lru and b_lru_flags are protected by
178 * bt_lru_lock and not by b_sema
179 */
180 struct list_head b_lru; /* lru list */
181 spinlock_t b_lock; /* internal state lock */
182 unsigned int b_state; /* internal state flags */
183 int b_io_error; /* internal IO error state */
184 wait_queue_head_t b_waiters; /* unpin waiters */
185 struct list_head b_list;
186 struct xfs_perag *b_pag; /* contains rbtree root */
187 struct xfs_mount *b_mount;
188 struct xfs_buftarg *b_target; /* buffer target (device) */
189 void *b_addr; /* virtual address of buffer */
190 struct work_struct b_ioend_work;
191 struct completion b_iowait; /* queue for I/O waiters */
192 struct xfs_buf_log_item *b_log_item;
193 struct list_head b_li_list; /* Log items list head */
194 struct xfs_trans *b_transp;
195 struct page **b_pages; /* array of page pointers */
196 struct page *b_page_array[XB_PAGES]; /* inline pages */
197 struct xfs_buf_map *b_maps; /* compound buffer map */
198 struct xfs_buf_map __b_map; /* inline compound buffer map */
199 int b_map_count;
200 atomic_t b_pin_count; /* pin count */
201 atomic_t b_io_remaining; /* #outstanding I/O requests */
202 unsigned int b_page_count; /* size of page array */
203 unsigned int b_offset; /* page offset of b_addr,
204 only for _XBF_KMEM buffers */
205 int b_error; /* error code on I/O */
206
207 /*
208 * async write failure retry count. Initialised to zero on the first
209 * failure, then when it exceeds the maximum configured without a
210 * success the write is considered to be failed permanently and the
211 * iodone handler will take appropriate action.
212 *
213 * For retry timeouts, we record the jiffie of the first failure. This
214 * means that we can change the retry timeout for buffers already under
215 * I/O and thus avoid getting stuck in a retry loop with a long timeout.
216 *
217 * last_error is used to ensure that we are getting repeated errors, not
218 * different errors. e.g. a block device might change ENOSPC to EIO when
219 * a failure timeout occurs, so we want to re-initialise the error
220 * retry behaviour appropriately when that happens.
221 */
222 int b_retries;
223 unsigned long b_first_retry_time; /* in jiffies */
224 int b_last_error;
225
226 const struct xfs_buf_ops *b_ops;
227 struct rcu_head b_rcu;
228 };
229
230 /* Finding and Reading Buffers */
231 int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
232 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
233 int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
234 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
235 const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
236 void xfs_buf_readahead_map(struct xfs_buftarg *target,
237 struct xfs_buf_map *map, int nmaps,
238 const struct xfs_buf_ops *ops);
239
240 static inline int
241 xfs_buf_incore(
242 struct xfs_buftarg *target,
243 xfs_daddr_t blkno,
244 size_t numblks,
245 xfs_buf_flags_t flags,
246 struct xfs_buf **bpp)
247 {
248 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
249
250 return xfs_buf_get_map(target, &map, 1, XBF_INCORE | flags, bpp);
251 }
252
253 static inline int
254 xfs_buf_get(
255 struct xfs_buftarg *target,
256 xfs_daddr_t blkno,
257 size_t numblks,
258 struct xfs_buf **bpp)
259 {
260 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
261
262 return xfs_buf_get_map(target, &map, 1, 0, bpp);
263 }
264
265 static inline int
266 xfs_buf_read(
267 struct xfs_buftarg *target,
268 xfs_daddr_t blkno,
269 size_t numblks,
270 xfs_buf_flags_t flags,
271 struct xfs_buf **bpp,
272 const struct xfs_buf_ops *ops)
273 {
274 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
275
276 return xfs_buf_read_map(target, &map, 1, flags, bpp, ops,
277 __builtin_return_address(0));
278 }
279
280 static inline void
281 xfs_buf_readahead(
282 struct xfs_buftarg *target,
283 xfs_daddr_t blkno,
284 size_t numblks,
285 const struct xfs_buf_ops *ops)
286 {
287 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
288 return xfs_buf_readahead_map(target, &map, 1, ops);
289 }
290
291 int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
292 xfs_buf_flags_t flags, struct xfs_buf **bpp);
293 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
294 size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
295 const struct xfs_buf_ops *ops);
296 int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
297 void xfs_buf_hold(struct xfs_buf *bp);
298
299 /* Releasing Buffers */
300 extern void xfs_buf_rele(struct xfs_buf *);
301
302 /* Locking and Unlocking Buffers */
303 extern int xfs_buf_trylock(struct xfs_buf *);
304 extern void xfs_buf_lock(struct xfs_buf *);
305 extern void xfs_buf_unlock(struct xfs_buf *);
306 #define xfs_buf_islocked(bp) \
307 ((bp)->b_sema.count <= 0)
308
309 static inline void xfs_buf_relse(struct xfs_buf *bp)
310 {
311 xfs_buf_unlock(bp);
312 xfs_buf_rele(bp);
313 }
314
315 /* Buffer Read and Write Routines */
316 extern int xfs_bwrite(struct xfs_buf *bp);
317
318 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
319 xfs_failaddr_t failaddr);
320 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
321 extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
322 void xfs_buf_ioend_fail(struct xfs_buf *);
323 void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
324 void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
325 #define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
326
327 /* Buffer Utility Routines */
328 extern void *xfs_buf_offset(struct xfs_buf *, size_t);
329 extern void xfs_buf_stale(struct xfs_buf *bp);
330
331 /* Delayed Write Buffer Routines */
332 extern void xfs_buf_delwri_cancel(struct list_head *);
333 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
334 void xfs_buf_delwri_queue_here(struct xfs_buf *bp, struct list_head *bl);
335 extern int xfs_buf_delwri_submit(struct list_head *);
336 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
337 extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
338
339 static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
340 {
341 return bp->b_maps[0].bm_bn;
342 }
343
344 void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
345
346 /*
347 * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
348 * up with a reference count of 0 so it will be tossed from the cache when
349 * released.
350 */
351 static inline void xfs_buf_oneshot(struct xfs_buf *bp)
352 {
353 if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
354 return;
355 atomic_set(&bp->b_lru_ref, 0);
356 }
357
358 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
359 {
360 return atomic_read(&bp->b_pin_count);
361 }
362
363 static inline int
364 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
365 {
366 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
367 cksum_offset);
368 }
369
370 static inline void
371 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
372 {
373 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
374 cksum_offset);
375 }
376
377 /*
378 * Handling of buftargs.
379 */
380 struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
381 struct file *bdev_file);
382 extern void xfs_free_buftarg(struct xfs_buftarg *);
383 extern void xfs_buftarg_wait(struct xfs_buftarg *);
384 extern void xfs_buftarg_drain(struct xfs_buftarg *);
385 extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);
386
387 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
388 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
389
390 int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
391 bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
392 bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
393
394 /* for xfs_buf_mem.c only: */
395 int xfs_init_buftarg(struct xfs_buftarg *btp, size_t logical_sectorsize,
396 const char *descr);
397 void xfs_destroy_buftarg(struct xfs_buftarg *btp);
398
399 #endif /* __XFS_BUF_H__ */
400
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