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