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 /*
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 typedef struct xfs_buftarg {
100 	dev_t			bt_dev;
101 	struct block_device	*bt_bdev;
102 	struct dax_device	*bt_daxdev;
103 	u64			bt_dax_part_off;
104 	struct xfs_mount	*bt_mount;
105 	unsigned int		bt_meta_sectorsize;
106 	size_t			bt_meta_sectormask;
107 	size_t			bt_logical_sectorsize;
108 	size_t			bt_logical_sectormask;
109 
110 	/* LRU control structures */
111 	struct shrinker		bt_shrinker;
112 	struct list_lru		bt_lru;
113 
114 	struct percpu_counter	bt_io_count;
115 	struct ratelimit_state	bt_ioerror_rl;
116 } xfs_buftarg_t;
117 
118 #define XB_PAGES	2
119 
120 struct xfs_buf_map {
121 	xfs_daddr_t		bm_bn;	/* block number for I/O */
122 	int			bm_len;	/* size of I/O */
123 	unsigned int		bm_flags;
124 };
125 
126 /*
127  * Online fsck is scanning the buffer cache for live buffers.  Do not warn
128  * about length mismatches during lookups and do not return stale buffers.
129  */
130 #define XBM_LIVESCAN		(1U << 0)
131 
132 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
133 	struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
134 
135 struct xfs_buf_ops {
136 	char *name;
137 	union {
138 		__be32 magic[2];	/* v4 and v5 on disk magic values */
139 		__be16 magic16[2];	/* v4 and v5 on disk magic values */
140 	};
141 	void (*verify_read)(struct xfs_buf *);
142 	void (*verify_write)(struct xfs_buf *);
143 	xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
144 };
145 
146 struct xfs_buf {
147 	/*
148 	 * first cacheline holds all the fields needed for an uncontended cache
149 	 * hit to be fully processed. The semaphore straddles the cacheline
150 	 * boundary, but the counter and lock sits on the first cacheline,
151 	 * which is the only bit that is touched if we hit the semaphore
152 	 * fast-path on locking.
153 	 */
154 	struct rhash_head	b_rhash_head;	/* pag buffer hash node */
155 
156 	xfs_daddr_t		b_rhash_key;	/* buffer cache index */
157 	int			b_length;	/* size of buffer in BBs */
158 	atomic_t		b_hold;		/* reference count */
159 	atomic_t		b_lru_ref;	/* lru reclaim ref count */
160 	xfs_buf_flags_t		b_flags;	/* status flags */
161 	struct semaphore	b_sema;		/* semaphore for lockables */
162 
163 	/*
164 	 * concurrent access to b_lru and b_lru_flags are protected by
165 	 * bt_lru_lock and not by b_sema
166 	 */
167 	struct list_head	b_lru;		/* lru list */
168 	spinlock_t		b_lock;		/* internal state lock */
169 	unsigned int		b_state;	/* internal state flags */
170 	int			b_io_error;	/* internal IO error state */
171 	wait_queue_head_t	b_waiters;	/* unpin waiters */
172 	struct list_head	b_list;
173 	struct xfs_perag	*b_pag;		/* contains rbtree root */
174 	struct xfs_mount	*b_mount;
175 	struct xfs_buftarg	*b_target;	/* buffer target (device) */
176 	void			*b_addr;	/* virtual address of buffer */
177 	struct work_struct	b_ioend_work;
178 	struct completion	b_iowait;	/* queue for I/O waiters */
179 	struct xfs_buf_log_item	*b_log_item;
180 	struct list_head	b_li_list;	/* Log items list head */
181 	struct xfs_trans	*b_transp;
182 	struct page		**b_pages;	/* array of page pointers */
183 	struct page		*b_page_array[XB_PAGES]; /* inline pages */
184 	struct xfs_buf_map	*b_maps;	/* compound buffer map */
185 	struct xfs_buf_map	__b_map;	/* inline compound buffer map */
186 	int			b_map_count;
187 	atomic_t		b_pin_count;	/* pin count */
188 	atomic_t		b_io_remaining;	/* #outstanding I/O requests */
189 	unsigned int		b_page_count;	/* size of page array */
190 	unsigned int		b_offset;	/* page offset of b_addr,
191 						   only for _XBF_KMEM buffers */
192 	int			b_error;	/* error code on I/O */
193 
194 	/*
195 	 * async write failure retry count. Initialised to zero on the first
196 	 * failure, then when it exceeds the maximum configured without a
197 	 * success the write is considered to be failed permanently and the
198 	 * iodone handler will take appropriate action.
199 	 *
200 	 * For retry timeouts, we record the jiffie of the first failure. This
201 	 * means that we can change the retry timeout for buffers already under
202 	 * I/O and thus avoid getting stuck in a retry loop with a long timeout.
203 	 *
204 	 * last_error is used to ensure that we are getting repeated errors, not
205 	 * different errors. e.g. a block device might change ENOSPC to EIO when
206 	 * a failure timeout occurs, so we want to re-initialise the error
207 	 * retry behaviour appropriately when that happens.
208 	 */
209 	int			b_retries;
210 	unsigned long		b_first_retry_time; /* in jiffies */
211 	int			b_last_error;
212 
213 	const struct xfs_buf_ops	*b_ops;
214 	struct rcu_head		b_rcu;
215 };
216 
217 /* Finding and Reading Buffers */
218 int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
219 		int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
220 int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
221 		int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
222 		const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
223 void xfs_buf_readahead_map(struct xfs_buftarg *target,
224 			       struct xfs_buf_map *map, int nmaps,
225 			       const struct xfs_buf_ops *ops);
226 
227 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)228 xfs_buf_incore(
229 	struct xfs_buftarg	*target,
230 	xfs_daddr_t		blkno,
231 	size_t			numblks,
232 	xfs_buf_flags_t		flags,
233 	struct xfs_buf		**bpp)
234 {
235 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
236 
237 	return xfs_buf_get_map(target, &map, 1, XBF_INCORE | flags, bpp);
238 }
239 
240 static inline int
xfs_buf_get(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,struct xfs_buf ** bpp)241 xfs_buf_get(
242 	struct xfs_buftarg	*target,
243 	xfs_daddr_t		blkno,
244 	size_t			numblks,
245 	struct xfs_buf		**bpp)
246 {
247 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
248 
249 	return xfs_buf_get_map(target, &map, 1, 0, bpp);
250 }
251 
252 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)253 xfs_buf_read(
254 	struct xfs_buftarg	*target,
255 	xfs_daddr_t		blkno,
256 	size_t			numblks,
257 	xfs_buf_flags_t		flags,
258 	struct xfs_buf		**bpp,
259 	const struct xfs_buf_ops *ops)
260 {
261 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
262 
263 	return xfs_buf_read_map(target, &map, 1, flags, bpp, ops,
264 			__builtin_return_address(0));
265 }
266 
267 static inline void
xfs_buf_readahead(struct xfs_buftarg * target,xfs_daddr_t blkno,size_t numblks,const struct xfs_buf_ops * ops)268 xfs_buf_readahead(
269 	struct xfs_buftarg	*target,
270 	xfs_daddr_t		blkno,
271 	size_t			numblks,
272 	const struct xfs_buf_ops *ops)
273 {
274 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
275 	return xfs_buf_readahead_map(target, &map, 1, ops);
276 }
277 
278 int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
279 		xfs_buf_flags_t flags, struct xfs_buf **bpp);
280 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
281 		size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
282 		const struct xfs_buf_ops *ops);
283 int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
284 void xfs_buf_hold(struct xfs_buf *bp);
285 
286 /* Releasing Buffers */
287 extern void xfs_buf_rele(struct xfs_buf *);
288 
289 /* Locking and Unlocking Buffers */
290 extern int xfs_buf_trylock(struct xfs_buf *);
291 extern void xfs_buf_lock(struct xfs_buf *);
292 extern void xfs_buf_unlock(struct xfs_buf *);
293 #define xfs_buf_islocked(bp) \
294 	((bp)->b_sema.count <= 0)
295 
xfs_buf_relse(struct xfs_buf * bp)296 static inline void xfs_buf_relse(struct xfs_buf *bp)
297 {
298 	xfs_buf_unlock(bp);
299 	xfs_buf_rele(bp);
300 }
301 
302 /* Buffer Read and Write Routines */
303 extern int xfs_bwrite(struct xfs_buf *bp);
304 
305 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
306 		xfs_failaddr_t failaddr);
307 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
308 extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
309 void xfs_buf_ioend_fail(struct xfs_buf *);
310 void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
311 void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
312 #define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
313 
314 /* Buffer Utility Routines */
315 extern void *xfs_buf_offset(struct xfs_buf *, size_t);
316 extern void xfs_buf_stale(struct xfs_buf *bp);
317 
318 /* Delayed Write Buffer Routines */
319 extern void xfs_buf_delwri_cancel(struct list_head *);
320 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
321 extern int xfs_buf_delwri_submit(struct list_head *);
322 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
323 extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
324 
xfs_buf_daddr(struct xfs_buf * bp)325 static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
326 {
327 	return bp->b_maps[0].bm_bn;
328 }
329 
330 void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
331 
332 /*
333  * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
334  * up with a reference count of 0 so it will be tossed from the cache when
335  * released.
336  */
xfs_buf_oneshot(struct xfs_buf * bp)337 static inline void xfs_buf_oneshot(struct xfs_buf *bp)
338 {
339 	if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
340 		return;
341 	atomic_set(&bp->b_lru_ref, 0);
342 }
343 
xfs_buf_ispinned(struct xfs_buf * bp)344 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
345 {
346 	return atomic_read(&bp->b_pin_count);
347 }
348 
349 static inline int
xfs_buf_verify_cksum(struct xfs_buf * bp,unsigned long cksum_offset)350 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
351 {
352 	return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
353 				cksum_offset);
354 }
355 
356 static inline void
xfs_buf_update_cksum(struct xfs_buf * bp,unsigned long cksum_offset)357 xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
358 {
359 	xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
360 			 cksum_offset);
361 }
362 
363 /*
364  *	Handling of buftargs.
365  */
366 struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
367 		struct block_device *bdev);
368 extern void xfs_free_buftarg(struct xfs_buftarg *);
369 extern void xfs_buftarg_wait(struct xfs_buftarg *);
370 extern void xfs_buftarg_drain(struct xfs_buftarg *);
371 extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);
372 
373 #define xfs_getsize_buftarg(buftarg)	block_size((buftarg)->bt_bdev)
374 #define xfs_readonly_buftarg(buftarg)	bdev_read_only((buftarg)->bt_bdev)
375 
376 int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
377 bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
378 bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
379 
380 #endif	/* __XFS_BUF_H__ */
381