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
18extern struct kmem_cache *xfs_buf_cache;
19
20/*
21 * Base types
22 */
23struct xfs_buf;
24
25#define XFS_BUF_DADDR_MAX ((xfs_daddr_t) S64_MAX)
26#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
27
28#define XBF_READ (1u << 0) /* buffer intended for reading from device */
29#define XBF_WRITE (1u << 1) /* buffer intended for writing to device */
30#define XBF_READ_AHEAD (1u << 2) /* asynchronous read-ahead */
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_LOGRECOVERY (1u << 18)/* log recovery buffer */
38
39/* flags used only internally */
40#define _XBF_KMEM (1u << 21)/* backed by heap memory */
41#define _XBF_DELWRI_Q (1u << 22)/* buffer on a delwri queue */
42
43/* flags used only as arguments to access routines */
44/*
45 * Online fsck is scanning the buffer cache for live buffers. Do not warn
46 * about length mismatches during lookups and do not return stale buffers.
47 */
48#define XBF_LIVESCAN (1u << 28)
49#define XBF_INCORE (1u << 29)/* lookup only, return if found in cache */
50#define XBF_TRYLOCK (1u << 30)/* lock requested, but do not wait */
51
52
53typedef unsigned int xfs_buf_flags_t;
54
55#define XFS_BUF_FLAGS \
56 { XBF_READ, "READ" }, \
57 { XBF_WRITE, "WRITE" }, \
58 { XBF_READ_AHEAD, "READ_AHEAD" }, \
59 { XBF_ASYNC, "ASYNC" }, \
60 { XBF_DONE, "DONE" }, \
61 { XBF_STALE, "STALE" }, \
62 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \
63 { _XBF_LOGRECOVERY, "LOG_RECOVERY" }, \
64 { _XBF_KMEM, "KMEM" }, \
65 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
66 /* The following interface flags should never be set */ \
67 { XBF_LIVESCAN, "LIVESCAN" }, \
68 { XBF_INCORE, "INCORE" }, \
69 { XBF_TRYLOCK, "TRYLOCK" }
70
71/*
72 * Internal state flags.
73 */
74#define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
75
76struct xfs_buf_cache {
77 struct rhashtable bc_hash;
78};
79
80int xfs_buf_cache_init(struct xfs_buf_cache *bch);
81void xfs_buf_cache_destroy(struct xfs_buf_cache *bch);
82
83/*
84 * The xfs_buftarg contains 2 notions of "sector size" -
85 *
86 * 1) The metadata sector size, which is the minimum unit and
87 * alignment of IO which will be performed by metadata operations.
88 * 2) The device logical sector size
89 *
90 * The first is specified at mkfs time, and is stored on-disk in the
91 * superblock's sb_sectsize.
92 *
93 * The latter is derived from the underlying device, and controls direct IO
94 * alignment constraints.
95 */
96struct xfs_buftarg {
97 dev_t bt_dev;
98 struct block_device *bt_bdev;
99 struct dax_device *bt_daxdev;
100 struct file *bt_file;
101 u64 bt_dax_part_off;
102 struct xfs_mount *bt_mount;
103 unsigned int bt_meta_sectorsize;
104 size_t bt_meta_sectormask;
105 size_t bt_logical_sectorsize;
106 size_t bt_logical_sectormask;
107 xfs_daddr_t bt_nr_sectors;
108
109 /* LRU control structures */
110 struct shrinker *bt_shrinker;
111 struct list_lru bt_lru;
112
113 struct percpu_counter bt_readahead_count;
114 struct ratelimit_state bt_ioerror_rl;
115
116 /* Hardware atomic write unit values, bytes */
117 unsigned int bt_awu_min;
118 unsigned int bt_awu_max;
119
120 /* built-in cache, if we're not using the perag one */
121 struct xfs_buf_cache bt_cache[];
122};
123
124struct xfs_buf_map {
125 xfs_daddr_t bm_bn; /* block number for I/O */
126 int bm_len; /* size of I/O */
127 unsigned int bm_flags;
128};
129
130/*
131 * Online fsck is scanning the buffer cache for live buffers. Do not warn
132 * about length mismatches during lookups and do not return stale buffers.
133 */
134#define XBM_LIVESCAN (1U << 0)
135
136#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
137 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
138
139struct xfs_buf_ops {
140 char *name;
141 union {
142 __be32 magic[2]; /* v4 and v5 on disk magic values */
143 __be16 magic16[2]; /* v4 and v5 on disk magic values */
144 };
145 void (*verify_read)(struct xfs_buf *);
146 void (*verify_write)(struct xfs_buf *);
147 xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
148};
149
150struct xfs_buf {
151 /*
152 * first cacheline holds all the fields needed for an uncontended cache
153 * hit to be fully processed. The semaphore straddles the cacheline
154 * boundary, but the counter and lock sits on the first cacheline,
155 * which is the only bit that is touched if we hit the semaphore
156 * fast-path on locking.
157 */
158 struct rhash_head b_rhash_head; /* pag buffer hash node */
159
160 xfs_daddr_t b_rhash_key; /* buffer cache index */
161 int b_length; /* size of buffer in BBs */
162 unsigned int b_hold; /* reference count */
163 atomic_t b_lru_ref; /* lru reclaim ref count */
164 xfs_buf_flags_t b_flags; /* status flags */
165 struct semaphore b_sema; /* semaphore for lockables */
166
167 /*
168 * concurrent access to b_lru and b_lru_flags are protected by
169 * bt_lru_lock and not by b_sema
170 */
171 struct list_head b_lru; /* lru list */
172 spinlock_t b_lock; /* internal state lock */
173 unsigned int b_state; /* internal state flags */
174 wait_queue_head_t b_waiters; /* unpin waiters */
175 struct list_head b_list;
176 struct xfs_perag *b_pag;
177 struct xfs_mount *b_mount;
178 struct xfs_buftarg *b_target; /* buffer target (device) */
179 void *b_addr; /* virtual address of buffer */
180 struct work_struct b_ioend_work;
181 struct completion b_iowait; /* queue for I/O waiters */
182 struct xfs_buf_log_item *b_log_item;
183 struct list_head b_li_list; /* Log items list head */
184 struct xfs_trans *b_transp;
185 struct xfs_buf_map *b_maps; /* compound buffer map */
186 struct xfs_buf_map __b_map; /* inline compound buffer map */
187 int b_map_count;
188 atomic_t b_pin_count; /* pin count */
189 int b_error; /* error code on I/O */
190 void (*b_iodone)(struct xfs_buf *bp);
191
192 /*
193 * async write failure retry count. Initialised to zero on the first
194 * failure, then when it exceeds the maximum configured without a
195 * success the write is considered to be failed permanently and the
196 * iodone handler will take appropriate action.
197 *
198 * For retry timeouts, we record the jiffy of the first failure. This
199 * means that we can change the retry timeout for buffers already under
200 * I/O and thus avoid getting stuck in a retry loop with a long timeout.
201 *
202 * last_error is used to ensure that we are getting repeated errors, not
203 * different errors. e.g. a block device might change ENOSPC to EIO when
204 * a failure timeout occurs, so we want to re-initialise the error
205 * retry behaviour appropriately when that happens.
206 */
207 int b_retries;
208 unsigned long b_first_retry_time; /* in jiffies */
209 int b_last_error;
210
211 const struct xfs_buf_ops *b_ops;
212 struct rcu_head b_rcu;
213};
214
215/* Finding and Reading Buffers */
216int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
217 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
218int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
219 int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
220 const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
221void xfs_buf_readahead_map(struct xfs_buftarg *target,
222 struct xfs_buf_map *map, int nmaps,
223 const struct xfs_buf_ops *ops);
224
225static inline int
226xfs_buf_incore(
227 struct xfs_buftarg *target,
228 xfs_daddr_t blkno,
229 size_t numblks,
230 xfs_buf_flags_t flags,
231 struct xfs_buf **bpp)
232{
233 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
234
235 return xfs_buf_get_map(target, map: &map, nmaps: 1, XBF_INCORE | flags, bpp);
236}
237
238static inline int
239xfs_buf_get(
240 struct xfs_buftarg *target,
241 xfs_daddr_t blkno,
242 size_t numblks,
243 struct xfs_buf **bpp)
244{
245 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
246
247 return xfs_buf_get_map(target, map: &map, nmaps: 1, flags: 0, bpp);
248}
249
250static inline int
251xfs_buf_read(
252 struct xfs_buftarg *target,
253 xfs_daddr_t blkno,
254 size_t numblks,
255 xfs_buf_flags_t flags,
256 struct xfs_buf **bpp,
257 const struct xfs_buf_ops *ops)
258{
259 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
260
261 return xfs_buf_read_map(target, map: &map, nmaps: 1, flags, bpp, ops,
262 fa: __builtin_return_address(0));
263}
264
265static inline void
266xfs_buf_readahead(
267 struct xfs_buftarg *target,
268 xfs_daddr_t blkno,
269 size_t numblks,
270 const struct xfs_buf_ops *ops)
271{
272 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
273 return xfs_buf_readahead_map(target, map: &map, nmaps: 1, ops);
274}
275
276int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
277 struct xfs_buf **bpp);
278int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
279 size_t numblks, struct xfs_buf **bpp,
280 const struct xfs_buf_ops *ops);
281int _xfs_buf_read(struct xfs_buf *bp);
282void xfs_buf_hold(struct xfs_buf *bp);
283
284/* Releasing Buffers */
285extern void xfs_buf_rele(struct xfs_buf *);
286
287/* Locking and Unlocking Buffers */
288extern int xfs_buf_trylock(struct xfs_buf *);
289extern void xfs_buf_lock(struct xfs_buf *);
290extern void xfs_buf_unlock(struct xfs_buf *);
291#define xfs_buf_islocked(bp) \
292 ((bp)->b_sema.count <= 0)
293
294static inline void xfs_buf_relse(struct xfs_buf *bp)
295{
296 xfs_buf_unlock(bp);
297 xfs_buf_rele(bp);
298}
299
300/* Buffer Read and Write Routines */
301extern int xfs_bwrite(struct xfs_buf *bp);
302
303extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
304 xfs_failaddr_t failaddr);
305#define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
306extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
307void xfs_buf_ioend_fail(struct xfs_buf *);
308void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
309#define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
310
311/* Buffer Utility Routines */
312static inline void *xfs_buf_offset(struct xfs_buf *bp, size_t offset)
313{
314 return bp->b_addr + offset;
315}
316
317static inline void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize)
318{
319 memset(bp->b_addr + boff, 0, bsize);
320}
321
322extern void xfs_buf_stale(struct xfs_buf *bp);
323
324/* Delayed Write Buffer Routines */
325extern void xfs_buf_delwri_cancel(struct list_head *);
326extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
327void xfs_buf_delwri_queue_here(struct xfs_buf *bp, struct list_head *bl);
328extern int xfs_buf_delwri_submit(struct list_head *);
329extern int xfs_buf_delwri_submit_nowait(struct list_head *);
330
331static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
332{
333 return bp->b_maps[0].bm_bn;
334}
335
336void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
337
338/*
339 * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
340 * up with a reference count of 0 so it will be tossed from the cache when
341 * released.
342 */
343static inline void xfs_buf_oneshot(struct xfs_buf *bp)
344{
345 if (!list_empty(head: &bp->b_lru) || atomic_read(v: &bp->b_lru_ref) > 1)
346 return;
347 atomic_set(v: &bp->b_lru_ref, i: 0);
348}
349
350static inline int xfs_buf_ispinned(struct xfs_buf *bp)
351{
352 return atomic_read(v: &bp->b_pin_count);
353}
354
355static inline int
356xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
357{
358 return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
359 cksum_offset);
360}
361
362static inline void
363xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
364{
365 xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
366 cksum_offset);
367}
368
369/*
370 * Handling of buftargs.
371 */
372struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
373 struct file *bdev_file);
374extern void xfs_free_buftarg(struct xfs_buftarg *);
375extern void xfs_buftarg_wait(struct xfs_buftarg *);
376extern void xfs_buftarg_drain(struct xfs_buftarg *);
377int xfs_configure_buftarg(struct xfs_buftarg *btp, unsigned int sectorsize,
378 xfs_fsblock_t nr_blocks);
379
380#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
381
382int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
383bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
384bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
385
386/* for xfs_buf_mem.c only: */
387int xfs_init_buftarg(struct xfs_buftarg *btp, size_t logical_sectorsize,
388 const char *descr);
389void xfs_destroy_buftarg(struct xfs_buftarg *btp);
390
391#endif /* __XFS_BUF_H__ */
392

source code of linux/fs/xfs/xfs_buf.h