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