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1/*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18#ifndef __XFS_BUF_H__
19#define __XFS_BUF_H__
20
21#include <linux/list.h>
22#include <linux/types.h>
23#include <linux/spinlock.h>
24#include <linux/mm.h>
25#include <linux/fs.h>
26#include <linux/buffer_head.h>
27#include <linux/uio.h>
28
29/*
30 * Base types
31 */
32
33#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
34
35typedef enum {
36 XBRW_READ = 1, /* transfer into target memory */
37 XBRW_WRITE = 2, /* transfer from target memory */
38 XBRW_ZERO = 3, /* Zero target memory */
39} xfs_buf_rw_t;
40
41#define XBF_READ (1 << 0) /* buffer intended for reading from device */
42#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
43#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
44#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
45#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
46#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
47
48/* I/O hints for the BIO layer */
49#define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
50#define XBF_FUA (1 << 11)/* force cache write through mode */
51#define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
52
53/* flags used only as arguments to access routines */
54#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
55#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
56
57/* flags used only internally */
58#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
59#define _XBF_KMEM (1 << 21)/* backed by heap memory */
60#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
61
62typedef unsigned int xfs_buf_flags_t;
63
64#define XFS_BUF_FLAGS \
65 { XBF_READ, "READ" }, \
66 { XBF_WRITE, "WRITE" }, \
67 { XBF_READ_AHEAD, "READ_AHEAD" }, \
68 { XBF_ASYNC, "ASYNC" }, \
69 { XBF_DONE, "DONE" }, \
70 { XBF_STALE, "STALE" }, \
71 { XBF_SYNCIO, "SYNCIO" }, \
72 { XBF_FUA, "FUA" }, \
73 { XBF_FLUSH, "FLUSH" }, \
74 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
75 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
76 { _XBF_PAGES, "PAGES" }, \
77 { _XBF_KMEM, "KMEM" }, \
78 { _XBF_DELWRI_Q, "DELWRI_Q" }
79
80typedef struct xfs_buftarg {
81 dev_t bt_dev;
82 struct block_device *bt_bdev;
83 struct backing_dev_info *bt_bdi;
84 struct xfs_mount *bt_mount;
85 unsigned int bt_bsize;
86 unsigned int bt_sshift;
87 size_t bt_smask;
88
89 /* LRU control structures */
90 struct shrinker bt_shrinker;
91 struct list_head bt_lru;
92 spinlock_t bt_lru_lock;
93 unsigned int bt_lru_nr;
94} xfs_buftarg_t;
95
96struct xfs_buf;
97typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
98
99#define XB_PAGES 2
100
101typedef struct xfs_buf {
102 /*
103 * first cacheline holds all the fields needed for an uncontended cache
104 * hit to be fully processed. The semaphore straddles the cacheline
105 * boundary, but the counter and lock sits on the first cacheline,
106 * which is the only bit that is touched if we hit the semaphore
107 * fast-path on locking.
108 */
109 struct rb_node b_rbnode; /* rbtree node */
110 xfs_daddr_t b_bn; /* block number for I/O */
111 int b_length; /* size of buffer in BBs */
112 atomic_t b_hold; /* reference count */
113 atomic_t b_lru_ref; /* lru reclaim ref count */
114 xfs_buf_flags_t b_flags; /* status flags */
115 struct semaphore b_sema; /* semaphore for lockables */
116
117 struct list_head b_lru; /* lru list */
118 wait_queue_head_t b_waiters; /* unpin waiters */
119 struct list_head b_list;
120 struct xfs_perag *b_pag; /* contains rbtree root */
121 xfs_buftarg_t *b_target; /* buffer target (device) */
122 void *b_addr; /* virtual address of buffer */
123 struct work_struct b_iodone_work;
124 xfs_buf_iodone_t b_iodone; /* I/O completion function */
125 struct completion b_iowait; /* queue for I/O waiters */
126 void *b_fspriv;
127 struct xfs_trans *b_transp;
128 struct page **b_pages; /* array of page pointers */
129 struct page *b_page_array[XB_PAGES]; /* inline pages */
130 int b_io_length; /* IO size in BBs */
131 atomic_t b_pin_count; /* pin count */
132 atomic_t b_io_remaining; /* #outstanding I/O requests */
133 unsigned int b_page_count; /* size of page array */
134 unsigned int b_offset; /* page offset in first page */
135 unsigned short b_error; /* error code on I/O */
136#ifdef XFS_BUF_LOCK_TRACKING
137 int b_last_holder;
138#endif
139} xfs_buf_t;
140
141
142/* Finding and Reading Buffers */
143struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target, xfs_daddr_t blkno,
144 size_t numblks, xfs_buf_flags_t flags,
145 struct xfs_buf *new_bp);
146#define xfs_incore(buftarg,blkno,len,lockit) \
147 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
148
149struct xfs_buf *xfs_buf_get(struct xfs_buftarg *target, xfs_daddr_t blkno,
150 size_t numblks, xfs_buf_flags_t flags);
151struct xfs_buf *xfs_buf_read(struct xfs_buftarg *target, xfs_daddr_t blkno,
152 size_t numblks, xfs_buf_flags_t flags);
153void xfs_buf_readahead(struct xfs_buftarg *target, xfs_daddr_t blkno,
154 size_t numblks);
155
156struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
157struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *target, xfs_daddr_t blkno,
158 size_t numblks, xfs_buf_flags_t flags);
159void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
160int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
161
162struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
163 int flags);
164struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
165 xfs_daddr_t daddr, size_t numblks, int flags);
166void xfs_buf_hold(struct xfs_buf *bp);
167
168/* Releasing Buffers */
169extern void xfs_buf_free(xfs_buf_t *);
170extern void xfs_buf_rele(xfs_buf_t *);
171
172/* Locking and Unlocking Buffers */
173extern int xfs_buf_trylock(xfs_buf_t *);
174extern void xfs_buf_lock(xfs_buf_t *);
175extern void xfs_buf_unlock(xfs_buf_t *);
176#define xfs_buf_islocked(bp) \
177 ((bp)->b_sema.count <= 0)
178
179/* Buffer Read and Write Routines */
180extern int xfs_bwrite(struct xfs_buf *bp);
181
182extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
183
184extern void xfs_buf_ioend(xfs_buf_t *, int);
185extern void xfs_buf_ioerror(xfs_buf_t *, int);
186extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
187extern void xfs_buf_iorequest(xfs_buf_t *);
188extern int xfs_buf_iowait(xfs_buf_t *);
189extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
190 xfs_buf_rw_t);
191#define xfs_buf_zero(bp, off, len) \
192 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
193
194static inline int xfs_buf_geterror(xfs_buf_t *bp)
195{
196 return bp ? bp->b_error : ENOMEM;
197}
198
199/* Buffer Utility Routines */
200extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
201
202/* Delayed Write Buffer Routines */
203extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
204extern int xfs_buf_delwri_submit(struct list_head *);
205extern int xfs_buf_delwri_submit_nowait(struct list_head *);
206
207/* Buffer Daemon Setup Routines */
208extern int xfs_buf_init(void);
209extern void xfs_buf_terminate(void);
210
211#define XFS_BUF_ZEROFLAGS(bp) \
212 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
213 XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
214
215void xfs_buf_stale(struct xfs_buf *bp);
216#define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
217#define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
218
219#define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
220#define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
221#define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
222
223#define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
224#define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
225#define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
226
227#define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
228#define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
229#define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
230
231#define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
232#define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
233#define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
234
235#define XFS_BUF_ADDR(bp) ((bp)->b_bn)
236#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
237
238static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
239{
240 atomic_set(&bp->b_lru_ref, lru_ref);
241}
242
243static inline int xfs_buf_ispinned(struct xfs_buf *bp)
244{
245 return atomic_read(&bp->b_pin_count);
246}
247
248static inline void xfs_buf_relse(xfs_buf_t *bp)
249{
250 xfs_buf_unlock(bp);
251 xfs_buf_rele(bp);
252}
253
254/*
255 * Handling of buftargs.
256 */
257extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
258 struct block_device *, int, const char *);
259extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
260extern void xfs_wait_buftarg(xfs_buftarg_t *);
261extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
262
263#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
264#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
265
266#endif /* __XFS_BUF_H__ */