xref: /linux/fs/xfs/xfs_buf.h (revision d9a9c94dbc8bfeab2b29f860d38e5056894813ec)
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_PAGES	 (1u << 20)/* backed by refcounted pages */
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 #define XBF_UNMAPPED	 (1u << 31)/* do not map the buffer */
52 
53 
54 typedef unsigned int xfs_buf_flags_t;
55 
56 #define XFS_BUF_FLAGS \
57 	{ XBF_READ,		"READ" }, \
58 	{ XBF_WRITE,		"WRITE" }, \
59 	{ XBF_READ_AHEAD,	"READ_AHEAD" }, \
60 	{ XBF_ASYNC,		"ASYNC" }, \
61 	{ XBF_DONE,		"DONE" }, \
62 	{ XBF_STALE,		"STALE" }, \
63 	{ XBF_WRITE_FAIL,	"WRITE_FAIL" }, \
64 	{ _XBF_LOGRECOVERY,	"LOG_RECOVERY" }, \
65 	{ _XBF_PAGES,		"PAGES" }, \
66 	{ _XBF_KMEM,		"KMEM" }, \
67 	{ _XBF_DELWRI_Q,	"DELWRI_Q" }, \
68 	/* The following interface flags should never be set */ \
69 	{ XBF_LIVESCAN,		"LIVESCAN" }, \
70 	{ XBF_INCORE,		"INCORE" }, \
71 	{ XBF_TRYLOCK,		"TRYLOCK" }, \
72 	{ XBF_UNMAPPED,		"UNMAPPED" }
73 
74 /*
75  * Internal state flags.
76  */
77 #define XFS_BSTATE_DISPOSE	 (1 << 0)	/* buffer being discarded */
78 
79 struct xfs_buf_cache {
80 	struct rhashtable	bc_hash;
81 };
82 
83 int xfs_buf_cache_init(struct xfs_buf_cache *bch);
84 void xfs_buf_cache_destroy(struct xfs_buf_cache *bch);
85 
86 /*
87  * The xfs_buftarg contains 2 notions of "sector size" -
88  *
89  * 1) The metadata sector size, which is the minimum unit and
90  *    alignment of IO which will be performed by metadata operations.
91  * 2) The device logical sector size
92  *
93  * The first is specified at mkfs time, and is stored on-disk in the
94  * superblock's sb_sectsize.
95  *
96  * The latter is derived from the underlying device, and controls direct IO
97  * alignment constraints.
98  */
99 struct xfs_buftarg {
100 	dev_t			bt_dev;
101 	struct file		*bt_bdev_file;
102 	struct block_device	*bt_bdev;
103 	struct dax_device	*bt_daxdev;
104 	struct file		*bt_file;
105 	u64			bt_dax_part_off;
106 	struct xfs_mount	*bt_mount;
107 	unsigned int		bt_meta_sectorsize;
108 	size_t			bt_meta_sectormask;
109 	size_t			bt_logical_sectorsize;
110 	size_t			bt_logical_sectormask;
111 
112 	/* LRU control structures */
113 	struct shrinker		*bt_shrinker;
114 	struct list_lru		bt_lru;
115 
116 	struct percpu_counter	bt_readahead_count;
117 	struct ratelimit_state	bt_ioerror_rl;
118 
119 	/* Atomic write unit values */
120 	unsigned int		bt_bdev_awu_min;
121 	unsigned int		bt_bdev_awu_max;
122 
123 	/* built-in cache, if we're not using the perag one */
124 	struct xfs_buf_cache	bt_cache[];
125 };
126 
127 #define XB_PAGES	2
128 
129 struct xfs_buf_map {
130 	xfs_daddr_t		bm_bn;	/* block number for I/O */
131 	int			bm_len;	/* size of I/O */
132 	unsigned int		bm_flags;
133 };
134 
135 /*
136  * Online fsck is scanning the buffer cache for live buffers.  Do not warn
137  * about length mismatches during lookups and do not return stale buffers.
138  */
139 #define XBM_LIVESCAN		(1U << 0)
140 
141 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
142 	struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
143 
144 struct xfs_buf_ops {
145 	char *name;
146 	union {
147 		__be32 magic[2];	/* v4 and v5 on disk magic values */
148 		__be16 magic16[2];	/* v4 and v5 on disk magic values */
149 	};
150 	void (*verify_read)(struct xfs_buf *);
151 	void (*verify_write)(struct xfs_buf *);
152 	xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
153 };
154 
155 struct xfs_buf {
156 	/*
157 	 * first cacheline holds all the fields needed for an uncontended cache
158 	 * hit to be fully processed. The semaphore straddles the cacheline
159 	 * boundary, but the counter and lock sits on the first cacheline,
160 	 * which is the only bit that is touched if we hit the semaphore
161 	 * fast-path on locking.
162 	 */
163 	struct rhash_head	b_rhash_head;	/* pag buffer hash node */
164 
165 	xfs_daddr_t		b_rhash_key;	/* buffer cache index */
166 	int			b_length;	/* size of buffer in BBs */
167 	unsigned int		b_hold;		/* reference count */
168 	atomic_t		b_lru_ref;	/* lru reclaim ref count */
169 	xfs_buf_flags_t		b_flags;	/* status flags */
170 	struct semaphore	b_sema;		/* semaphore for lockables */
171 
172 	/*
173 	 * concurrent access to b_lru and b_lru_flags are protected by
174 	 * bt_lru_lock and not by b_sema
175 	 */
176 	struct list_head	b_lru;		/* lru list */
177 	spinlock_t		b_lock;		/* internal state lock */
178 	unsigned int		b_state;	/* internal state flags */
179 	wait_queue_head_t	b_waiters;	/* unpin waiters */
180 	struct list_head	b_list;
181 	struct xfs_perag	*b_pag;
182 	struct xfs_mount	*b_mount;
183 	struct xfs_buftarg	*b_target;	/* buffer target (device) */
184 	void			*b_addr;	/* virtual address of buffer */
185 	struct work_struct	b_ioend_work;
186 	struct completion	b_iowait;	/* queue for I/O waiters */
187 	struct xfs_buf_log_item	*b_log_item;
188 	struct list_head	b_li_list;	/* Log items list head */
189 	struct xfs_trans	*b_transp;
190 	struct page		**b_pages;	/* array of page pointers */
191 	struct page		*b_page_array[XB_PAGES]; /* inline pages */
192 	struct xfs_buf_map	*b_maps;	/* compound buffer map */
193 	struct xfs_buf_map	__b_map;	/* inline compound buffer map */
194 	int			b_map_count;
195 	atomic_t		b_pin_count;	/* pin count */
196 	unsigned int		b_page_count;	/* size of page array */
197 	unsigned int		b_offset;	/* page offset of b_addr,
198 						   only for _XBF_KMEM buffers */
199 	int			b_error;	/* error code on I/O */
200 	void			(*b_iodone)(struct xfs_buf *bp);
201 
202 	/*
203 	 * async write failure retry count. Initialised to zero on the first
204 	 * failure, then when it exceeds the maximum configured without a
205 	 * success the write is considered to be failed permanently and the
206 	 * iodone handler will take appropriate action.
207 	 *
208 	 * For retry timeouts, we record the jiffy of the first failure. This
209 	 * means that we can change the retry timeout for buffers already under
210 	 * I/O and thus avoid getting stuck in a retry loop with a long timeout.
211 	 *
212 	 * last_error is used to ensure that we are getting repeated errors, not
213 	 * different errors. e.g. a block device might change ENOSPC to EIO when
214 	 * a failure timeout occurs, so we want to re-initialise the error
215 	 * retry behaviour appropriately when that happens.
216 	 */
217 	int			b_retries;
218 	unsigned long		b_first_retry_time; /* in jiffies */
219 	int			b_last_error;
220 
221 	const struct xfs_buf_ops	*b_ops;
222 	struct rcu_head		b_rcu;
223 };
224 
225 /* Finding and Reading Buffers */
226 int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
227 		int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
228 int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
229 		int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
230 		const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
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 int
xfs_buf_incore(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,xfs_buf_flags_t flags,struct xfs_buf ** bpp)236 xfs_buf_incore(
237 	struct xfs_buftarg	*target,
238 	xfs_daddr_t		blkno,
239 	size_t			numblks,
240 	xfs_buf_flags_t		flags,
241 	struct xfs_buf		**bpp)
242 {
243 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
244 
245 	return xfs_buf_get_map(target, &map, 1, XBF_INCORE | flags, bpp);
246 }
247 
248 static inline int
xfs_buf_get(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,struct xfs_buf ** bpp)249 xfs_buf_get(
250 	struct xfs_buftarg	*target,
251 	xfs_daddr_t		blkno,
252 	size_t			numblks,
253 	struct xfs_buf		**bpp)
254 {
255 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
256 
257 	return xfs_buf_get_map(target, &map, 1, 0, bpp);
258 }
259 
260 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)261 xfs_buf_read(
262 	struct xfs_buftarg	*target,
263 	xfs_daddr_t		blkno,
264 	size_t			numblks,
265 	xfs_buf_flags_t		flags,
266 	struct xfs_buf		**bpp,
267 	const struct xfs_buf_ops *ops)
268 {
269 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
270 
271 	return xfs_buf_read_map(target, &map, 1, flags, bpp, ops,
272 			__builtin_return_address(0));
273 }
274 
275 static inline void
xfs_buf_readahead(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,const struct xfs_buf_ops * ops)276 xfs_buf_readahead(
277 	struct xfs_buftarg	*target,
278 	xfs_daddr_t		blkno,
279 	size_t			numblks,
280 	const struct xfs_buf_ops *ops)
281 {
282 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
283 	return xfs_buf_readahead_map(target, &map, 1, ops);
284 }
285 
286 int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
287 		xfs_buf_flags_t flags, struct xfs_buf **bpp);
288 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
289 		size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
290 		const struct xfs_buf_ops *ops);
291 int _xfs_buf_read(struct xfs_buf *bp);
292 void xfs_buf_hold(struct xfs_buf *bp);
293 
294 /* Releasing Buffers */
295 extern void xfs_buf_rele(struct xfs_buf *);
296 
297 /* Locking and Unlocking Buffers */
298 extern int xfs_buf_trylock(struct xfs_buf *);
299 extern void xfs_buf_lock(struct xfs_buf *);
300 extern void xfs_buf_unlock(struct xfs_buf *);
301 #define xfs_buf_islocked(bp) \
302 	((bp)->b_sema.count <= 0)
303 
xfs_buf_relse(struct xfs_buf * bp)304 static inline void xfs_buf_relse(struct xfs_buf *bp)
305 {
306 	xfs_buf_unlock(bp);
307 	xfs_buf_rele(bp);
308 }
309 
310 /* Buffer Read and Write Routines */
311 extern int xfs_bwrite(struct xfs_buf *bp);
312 
313 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
314 		xfs_failaddr_t failaddr);
315 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
316 extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
317 void xfs_buf_ioend_fail(struct xfs_buf *);
318 void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
319 void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
320 #define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
321 
322 /* Buffer Utility Routines */
323 extern void *xfs_buf_offset(struct xfs_buf *, size_t);
324 extern void xfs_buf_stale(struct xfs_buf *bp);
325 
326 /* Delayed Write Buffer Routines */
327 extern void xfs_buf_delwri_cancel(struct list_head *);
328 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
329 void xfs_buf_delwri_queue_here(struct xfs_buf *bp, struct list_head *bl);
330 extern int xfs_buf_delwri_submit(struct list_head *);
331 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
332 extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
333 
xfs_buf_daddr(struct xfs_buf * bp)334 static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
335 {
336 	return bp->b_maps[0].bm_bn;
337 }
338 
339 void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
340 
341 /*
342  * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
343  * up with a reference count of 0 so it will be tossed from the cache when
344  * released.
345  */
xfs_buf_oneshot(struct xfs_buf * bp)346 static inline void xfs_buf_oneshot(struct xfs_buf *bp)
347 {
348 	if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
349 		return;
350 	atomic_set(&bp->b_lru_ref, 0);
351 }
352 
xfs_buf_ispinned(struct xfs_buf * bp)353 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
354 {
355 	return atomic_read(&bp->b_pin_count);
356 }
357 
358 static inline int
xfs_buf_verify_cksum(struct xfs_buf * bp,unsigned long cksum_offset)359 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
360 {
361 	return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
362 				cksum_offset);
363 }
364 
365 static inline void
xfs_buf_update_cksum(struct xfs_buf * bp,unsigned long cksum_offset)366 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
367 {
368 	xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
369 			 cksum_offset);
370 }
371 
372 /*
373  *	Handling of buftargs.
374  */
375 struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
376 		struct file *bdev_file);
377 extern void xfs_free_buftarg(struct xfs_buftarg *);
378 extern void xfs_buftarg_wait(struct xfs_buftarg *);
379 extern void xfs_buftarg_drain(struct xfs_buftarg *);
380 extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);
381 
382 #define xfs_getsize_buftarg(buftarg)	block_size((buftarg)->bt_bdev)
383 #define xfs_readonly_buftarg(buftarg)	bdev_read_only((buftarg)->bt_bdev)
384 
385 int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
386 bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
387 bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
388 
389 /* for xfs_buf_mem.c only: */
390 int xfs_init_buftarg(struct xfs_buftarg *btp, size_t logical_sectorsize,
391 		const char *descr);
392 void xfs_destroy_buftarg(struct xfs_buftarg *btp);
393 
394 #endif	/* __XFS_BUF_H__ */
395