xref: /openbmc/linux/fs/xfs/xfs_buf.h (revision 3a2699cf)
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	 (1u << 0) /* buffer intended for reading from device */
26  #define XBF_WRITE	 (1u << 1) /* buffer intended for writing to device */
27  #define XBF_READ_AHEAD	 (1u << 2) /* asynchronous read-ahead */
28  #define XBF_NO_IOACCT	 (1u << 3) /* bypass I/O accounting (non-LRU bufs) */
29  #define XBF_ASYNC	 (1u << 4) /* initiator will not wait for completion */
30  #define XBF_DONE	 (1u << 5) /* all pages in the buffer uptodate */
31  #define XBF_STALE	 (1u << 6) /* buffer has been staled, do not find it */
32  #define XBF_WRITE_FAIL	 (1u << 7) /* async writes have failed on this buffer */
33  
34  /* buffer type flags for write callbacks */
35  #define _XBF_INODES	 (1u << 16)/* inode buffer */
36  #define _XBF_DQUOTS	 (1u << 17)/* dquot buffer */
37  #define _XBF_LOGRECOVERY (1u << 18)/* log recovery buffer */
38  
39  /* flags used only internally */
40  #define _XBF_PAGES	 (1u << 20)/* backed by refcounted pages */
41  #define _XBF_KMEM	 (1u << 21)/* backed by heap memory */
42  #define _XBF_DELWRI_Q	 (1u << 22)/* buffer on a delwri queue */
43  
44  /* flags used only as arguments to access routines */
45  #define XBF_TRYLOCK	 (1u << 30)/* lock requested, but do not wait */
46  #define XBF_UNMAPPED	 (1u << 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  	u64			bt_dax_part_off;
93  	struct xfs_mount	*bt_mount;
94  	unsigned int		bt_meta_sectorsize;
95  	size_t			bt_meta_sectormask;
96  	size_t			bt_logical_sectorsize;
97  	size_t			bt_logical_sectormask;
98  
99  	/* LRU control structures */
100  	struct shrinker		bt_shrinker;
101  	struct list_lru		bt_lru;
102  
103  	struct percpu_counter	bt_io_count;
104  	struct ratelimit_state	bt_ioerror_rl;
105  } xfs_buftarg_t;
106  
107  #define XB_PAGES	2
108  
109  struct xfs_buf_map {
110  	xfs_daddr_t		bm_bn;	/* block number for I/O */
111  	int			bm_len;	/* size of I/O */
112  };
113  
114  #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
115  	struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
116  
117  struct xfs_buf_ops {
118  	char *name;
119  	union {
120  		__be32 magic[2];	/* v4 and v5 on disk magic values */
121  		__be16 magic16[2];	/* v4 and v5 on disk magic values */
122  	};
123  	void (*verify_read)(struct xfs_buf *);
124  	void (*verify_write)(struct xfs_buf *);
125  	xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
126  };
127  
128  struct xfs_buf {
129  	/*
130  	 * first cacheline holds all the fields needed for an uncontended cache
131  	 * hit to be fully processed. The semaphore straddles the cacheline
132  	 * boundary, but the counter and lock sits on the first cacheline,
133  	 * which is the only bit that is touched if we hit the semaphore
134  	 * fast-path on locking.
135  	 */
136  	struct rhash_head	b_rhash_head;	/* pag buffer hash node */
137  
138  	xfs_daddr_t		b_rhash_key;	/* buffer cache index */
139  	int			b_length;	/* size of buffer in BBs */
140  	atomic_t		b_hold;		/* reference count */
141  	atomic_t		b_lru_ref;	/* lru reclaim ref count */
142  	xfs_buf_flags_t		b_flags;	/* status flags */
143  	struct semaphore	b_sema;		/* semaphore for lockables */
144  
145  	/*
146  	 * concurrent access to b_lru and b_lru_flags are protected by
147  	 * bt_lru_lock and not by b_sema
148  	 */
149  	struct list_head	b_lru;		/* lru list */
150  	spinlock_t		b_lock;		/* internal state lock */
151  	unsigned int		b_state;	/* internal state flags */
152  	int			b_io_error;	/* internal IO error state */
153  	wait_queue_head_t	b_waiters;	/* unpin waiters */
154  	struct list_head	b_list;
155  	struct xfs_perag	*b_pag;		/* contains rbtree root */
156  	struct xfs_mount	*b_mount;
157  	struct xfs_buftarg	*b_target;	/* buffer target (device) */
158  	void			*b_addr;	/* virtual address of buffer */
159  	struct work_struct	b_ioend_work;
160  	struct completion	b_iowait;	/* queue for I/O waiters */
161  	struct xfs_buf_log_item	*b_log_item;
162  	struct list_head	b_li_list;	/* Log items list head */
163  	struct xfs_trans	*b_transp;
164  	struct page		**b_pages;	/* array of page pointers */
165  	struct page		*b_page_array[XB_PAGES]; /* inline pages */
166  	struct xfs_buf_map	*b_maps;	/* compound buffer map */
167  	struct xfs_buf_map	__b_map;	/* inline compound buffer map */
168  	int			b_map_count;
169  	atomic_t		b_pin_count;	/* pin count */
170  	atomic_t		b_io_remaining;	/* #outstanding I/O requests */
171  	unsigned int		b_page_count;	/* size of page array */
172  	unsigned int		b_offset;	/* page offset of b_addr,
173  						   only for _XBF_KMEM buffers */
174  	int			b_error;	/* error code on I/O */
175  
176  	/*
177  	 * async write failure retry count. Initialised to zero on the first
178  	 * failure, then when it exceeds the maximum configured without a
179  	 * success the write is considered to be failed permanently and the
180  	 * iodone handler will take appropriate action.
181  	 *
182  	 * For retry timeouts, we record the jiffie of the first failure. This
183  	 * means that we can change the retry timeout for buffers already under
184  	 * I/O and thus avoid getting stuck in a retry loop with a long timeout.
185  	 *
186  	 * last_error is used to ensure that we are getting repeated errors, not
187  	 * different errors. e.g. a block device might change ENOSPC to EIO when
188  	 * a failure timeout occurs, so we want to re-initialise the error
189  	 * retry behaviour appropriately when that happens.
190  	 */
191  	int			b_retries;
192  	unsigned long		b_first_retry_time; /* in jiffies */
193  	int			b_last_error;
194  
195  	const struct xfs_buf_ops	*b_ops;
196  };
197  
198  /* Finding and Reading Buffers */
199  struct xfs_buf *xfs_buf_incore(struct xfs_buftarg *target,
200  			   xfs_daddr_t blkno, size_t numblks,
201  			   xfs_buf_flags_t flags);
202  
203  int xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
204  		int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp);
205  int xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map,
206  		int nmaps, xfs_buf_flags_t flags, struct xfs_buf **bpp,
207  		const struct xfs_buf_ops *ops, xfs_failaddr_t fa);
208  void xfs_buf_readahead_map(struct xfs_buftarg *target,
209  			       struct xfs_buf_map *map, int nmaps,
210  			       const struct xfs_buf_ops *ops);
211  
212  static inline int
213  xfs_buf_get(
214  	struct xfs_buftarg	*target,
215  	xfs_daddr_t		blkno,
216  	size_t			numblks,
217  	struct xfs_buf		**bpp)
218  {
219  	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
220  
221  	return xfs_buf_get_map(target, &map, 1, 0, bpp);
222  }
223  
224  static inline int
225  xfs_buf_read(
226  	struct xfs_buftarg	*target,
227  	xfs_daddr_t		blkno,
228  	size_t			numblks,
229  	xfs_buf_flags_t		flags,
230  	struct xfs_buf		**bpp,
231  	const struct xfs_buf_ops *ops)
232  {
233  	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
234  
235  	return xfs_buf_read_map(target, &map, 1, flags, bpp, ops,
236  			__builtin_return_address(0));
237  }
238  
239  static inline void
240  xfs_buf_readahead(
241  	struct xfs_buftarg	*target,
242  	xfs_daddr_t		blkno,
243  	size_t			numblks,
244  	const struct xfs_buf_ops *ops)
245  {
246  	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
247  	return xfs_buf_readahead_map(target, &map, 1, ops);
248  }
249  
250  int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
251  		xfs_buf_flags_t flags, struct xfs_buf **bpp);
252  int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
253  		size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
254  		const struct xfs_buf_ops *ops);
255  int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
256  void xfs_buf_hold(struct xfs_buf *bp);
257  
258  /* Releasing Buffers */
259  extern void xfs_buf_rele(struct xfs_buf *);
260  
261  /* Locking and Unlocking Buffers */
262  extern int xfs_buf_trylock(struct xfs_buf *);
263  extern void xfs_buf_lock(struct xfs_buf *);
264  extern void xfs_buf_unlock(struct xfs_buf *);
265  #define xfs_buf_islocked(bp) \
266  	((bp)->b_sema.count <= 0)
267  
268  static inline void xfs_buf_relse(struct xfs_buf *bp)
269  {
270  	xfs_buf_unlock(bp);
271  	xfs_buf_rele(bp);
272  }
273  
274  /* Buffer Read and Write Routines */
275  extern int xfs_bwrite(struct xfs_buf *bp);
276  
277  extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
278  		xfs_failaddr_t failaddr);
279  #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
280  extern void xfs_buf_ioerror_alert(struct xfs_buf *bp, xfs_failaddr_t fa);
281  void xfs_buf_ioend_fail(struct xfs_buf *);
282  void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
283  void __xfs_buf_mark_corrupt(struct xfs_buf *bp, xfs_failaddr_t fa);
284  #define xfs_buf_mark_corrupt(bp) __xfs_buf_mark_corrupt((bp), __this_address)
285  
286  /* Buffer Utility Routines */
287  extern void *xfs_buf_offset(struct xfs_buf *, size_t);
288  extern void xfs_buf_stale(struct xfs_buf *bp);
289  
290  /* Delayed Write Buffer Routines */
291  extern void xfs_buf_delwri_cancel(struct list_head *);
292  extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
293  extern int xfs_buf_delwri_submit(struct list_head *);
294  extern int xfs_buf_delwri_submit_nowait(struct list_head *);
295  extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
296  
297  /* Buffer Daemon Setup Routines */
298  extern int xfs_buf_init(void);
299  extern void xfs_buf_terminate(void);
300  
301  static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
302  {
303  	return bp->b_maps[0].bm_bn;
304  }
305  
306  void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
307  
308  /*
309   * If the buffer is already on the LRU, do nothing. Otherwise set the buffer
310   * up with a reference count of 0 so it will be tossed from the cache when
311   * released.
312   */
313  static inline void xfs_buf_oneshot(struct xfs_buf *bp)
314  {
315  	if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
316  		return;
317  	atomic_set(&bp->b_lru_ref, 0);
318  }
319  
320  static inline int xfs_buf_ispinned(struct xfs_buf *bp)
321  {
322  	return atomic_read(&bp->b_pin_count);
323  }
324  
325  static inline int
326  xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
327  {
328  	return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
329  				cksum_offset);
330  }
331  
332  static inline void
333  xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
334  {
335  	xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
336  			 cksum_offset);
337  }
338  
339  /*
340   *	Handling of buftargs.
341   */
342  struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
343  		struct block_device *bdev);
344  extern void xfs_free_buftarg(struct xfs_buftarg *);
345  extern void xfs_buftarg_wait(struct xfs_buftarg *);
346  extern void xfs_buftarg_drain(struct xfs_buftarg *);
347  extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);
348  
349  #define xfs_getsize_buftarg(buftarg)	block_size((buftarg)->bt_bdev)
350  #define xfs_readonly_buftarg(buftarg)	bdev_read_only((buftarg)->bt_bdev)
351  
352  int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
353  bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
354  bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
355  
356  #endif	/* __XFS_BUF_H__ */
357