Stop depending upon an implicit 'int' as the return type of main().
[dragonfly.git] / sys / sys / buf.h
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1/*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)buf.h 8.9 (Berkeley) 3/30/95
39 * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
54f51aeb 40 * $DragonFly: src/sys/sys/buf.h,v 1.9 2004/07/14 03:10:17 hmp Exp $
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41 */
42
43#ifndef _SYS_BUF_H_
44#define _SYS_BUF_H_
45
335dda38 46#ifndef _SYS_QUEUE_H_
984263bc 47#include <sys/queue.h>
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48#endif
49#ifndef _SYS_LOCK_H_
984263bc 50#include <sys/lock.h>
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51#endif
52#ifndef _SYS_DEVICE_H_
53#include <sys/device.h>
54#endif
984263bc 55
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56#ifndef _SYS_XIO_H_
57#include <sys/xio.h>
58#endif
59
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60struct buf;
61struct mount;
62struct vnode;
54f51aeb 63struct xio;
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64
65/*
66 * To avoid including <ufs/ffs/softdep.h>
67 */
68LIST_HEAD(workhead, worklist);
69/*
70 * These are currently used only by the soft dependency code, hence
71 * are stored once in a global variable. If other subsystems wanted
72 * to use these hooks, a pointer to a set of bio_ops could be added
73 * to each buffer.
74 */
75extern struct bio_ops {
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76 void (*io_start) (struct buf *);
77 void (*io_complete) (struct buf *);
78 void (*io_deallocate) (struct buf *);
79 int (*io_fsync) (struct vnode *);
80 int (*io_sync) (struct mount *);
81 void (*io_movedeps) (struct buf *, struct buf *);
82 int (*io_countdeps) (struct buf *, int);
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83} bioops;
84
85struct iodone_chain {
86 long ic_prev_flags;
b153f746 87 void (*ic_prev_iodone) (struct buf *);
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88 void *ic_prev_iodone_chain;
89 struct {
90 long ia_long;
91 void *ia_ptr;
92 } ic_args[5];
93};
94
95/*
96 * The buffer header describes an I/O operation in the kernel.
97 *
98 * NOTES:
99 * b_bufsize, b_bcount. b_bufsize is the allocation size of the
100 * buffer, either DEV_BSIZE or PAGE_SIZE aligned. b_bcount is the
101 * originally requested buffer size and can serve as a bounds check
102 * against EOF. For most, but not all uses, b_bcount == b_bufsize.
103 *
104 * b_dirtyoff, b_dirtyend. Buffers support piecemeal, unaligned
105 * ranges of dirty data that need to be written to backing store.
106 * The range is typically clipped at b_bcount ( not b_bufsize ).
107 *
108 * b_resid. Number of bytes remaining in I/O. After an I/O operation
109 * completes, b_resid is usually 0 indicating 100% success.
110 */
111struct buf {
112 LIST_ENTRY(buf) b_hash; /* Hash chain. */
113 TAILQ_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
114 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
115 TAILQ_ENTRY(buf) b_act; /* Device driver queue when active. *new* */
116 long b_flags; /* B_* flags. */
117 unsigned short b_qindex; /* buffer queue index */
118 unsigned char b_xflags; /* extra flags */
119 struct lock b_lock; /* Buffer lock */
120 int b_error; /* Errno value. */
121 long b_bufsize; /* Allocated buffer size. */
122 long b_runningbufspace; /* when I/O is running, pipelining */
123 long b_bcount; /* Valid bytes in buffer. */
124 long b_resid; /* Remaining I/O. */
125 dev_t b_dev; /* Device associated with buffer. */
126 caddr_t b_data; /* Memory, superblocks, indirect etc. */
127 caddr_t b_kvabase; /* base kva for buffer */
128 int b_kvasize; /* size of kva for buffer */
129 daddr_t b_lblkno; /* Logical block number. */
130 daddr_t b_blkno; /* Underlying physical block number. */
131 off_t b_offset; /* Offset into file */
132 /* Function to call upon completion. */
b153f746 133 void (*b_iodone) (struct buf *);
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134 /* For nested b_iodone's. */
135 struct iodone_chain *b_iodone_chain;
136 struct vnode *b_vp; /* Device vnode. */
137 int b_dirtyoff; /* Offset in buffer of dirty region. */
138 int b_dirtyend; /* Offset of end of dirty region. */
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139 daddr_t b_pblkno; /* physical block number */
140 void *b_saveaddr; /* Original b_addr for physio. */
141 void *b_driver1; /* for private use by the driver */
142 void *b_driver2; /* for private use by the driver */
143 void *b_caller1; /* for private use by the caller */
144 void *b_caller2; /* for private use by the caller */
145 union pager_info {
146 void *pg_spc;
147 int pg_reqpage;
148 } b_pager;
149 union cluster_info {
150 TAILQ_HEAD(cluster_list_head, buf) cluster_head;
151 TAILQ_ENTRY(buf) cluster_entry;
152 } b_cluster;
54f51aeb 153 struct xio b_xio;
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154 struct workhead b_dep; /* List of filesystem dependencies. */
155 struct chain_info { /* buffer chaining */
156 struct buf *parent;
157 int count;
158 } b_chain;
159};
160
161#define b_spc b_pager.pg_spc
162
163/*
164 * These flags are kept in b_flags.
165 *
166 * Notes:
167 *
168 * B_ASYNC VOP calls on bp's are usually async whether or not
169 * B_ASYNC is set, but some subsystems, such as NFS, like
170 * to know what is best for the caller so they can
171 * optimize the I/O.
172 *
173 * B_PAGING Indicates that bp is being used by the paging system or
174 * some paging system and that the bp is not linked into
175 * the b_vp's clean/dirty linked lists or ref counts.
176 * Buffer vp reassignments are illegal in this case.
177 *
178 * B_CACHE This may only be set if the buffer is entirely valid.
179 * The situation where B_DELWRI is set and B_CACHE is
180 * clear MUST be committed to disk by getblk() so
181 * B_DELWRI can also be cleared. See the comments for
182 * getblk() in kern/vfs_bio.c. If B_CACHE is clear,
183 * the caller is expected to clear B_ERROR|B_INVAL,
184 * set B_READ, and initiate an I/O.
185 *
186 * The 'entire buffer' is defined to be the range from
187 * 0 through b_bcount.
188 *
189 * B_MALLOC Request that the buffer be allocated from the malloc
190 * pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
191 *
192 * B_CLUSTEROK This flag is typically set for B_DELWRI buffers
193 * by filesystems that allow clustering when the buffer
194 * is fully dirty and indicates that it may be clustered
195 * with other adjacent dirty buffers. Note the clustering
196 * may not be used with the stage 1 data write under NFS
197 * but may be used for the commit rpc portion.
198 *
199 * B_VMIO Indicates that the buffer is tied into an VM object.
200 * The buffer's data is always PAGE_SIZE aligned even
201 * if b_bufsize and b_bcount are not. ( b_bufsize is
202 * always at least DEV_BSIZE aligned, though ).
203 *
204 * B_DIRECT Hint that we should attempt to completely free
205 * the pages underlying the buffer. B_DIRECT is
206 * sticky until the buffer is released and typically
207 * only has an effect when B_RELBUF is also set.
208 *
209 * B_NOWDRAIN This flag should be set when a device (like VN)
210 * does a turn-around VOP_WRITE from its strategy
211 * routine. This flag prevents bwrite() from blocking
212 * in wdrain, avoiding a deadlock situation.
213 */
214
215#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
216#define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
217#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
218#define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */
219#define B_DEFERRED 0x00000010 /* Skipped over for cleaning */
220#define B_CACHE 0x00000020 /* Bread found us in the cache. */
221#define B_CALL 0x00000040 /* Call b_iodone from biodone. */
222#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
223#define B_FREEBUF 0x00000100 /* Instruct driver: free blocks */
224#define B_DONE 0x00000200 /* I/O completed. */
225#define B_EINTR 0x00000400 /* I/O was interrupted */
226#define B_ERROR 0x00000800 /* I/O error occurred. */
227#define B_SCANNED 0x00001000 /* VOP_FSYNC funcs mark written bufs */
228#define B_INVAL 0x00002000 /* Does not contain valid info. */
229#define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
230#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
231#define B_MALLOC 0x00010000 /* malloced b_data */
232#define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
233#define B_PHYS 0x00040000 /* I/O to user memory. */
234#define B_RAW 0x00080000 /* Set by physio for raw transfers. */
235#define B_READ 0x00100000 /* Read buffer. */
236#define B_DIRTY 0x00200000 /* Needs writing later. */
237#define B_RELBUF 0x00400000 /* Release VMIO buffer. */
238#define B_WANT 0x00800000 /* Used by vm_pager.c */
239#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
240#define B_WRITEINPROG 0x01000000 /* Write in progress. */
241#define B_XXX 0x02000000 /* Debugging flag. */
242#define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
243#define B_ORDERED 0x08000000 /* Must guarantee I/O ordering */
244#define B_RAM 0x10000000 /* Read ahead mark (flag) */
245#define B_VMIO 0x20000000 /* VMIO flag */
246#define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
247#define B_NOWDRAIN 0x80000000 /* Avoid wdrain deadlock */
248
249#define PRINT_BUF_FLAGS "\20\40nowdrain\37cluster\36vmio\35ram\34ordered" \
250 "\33paging\32xxx\31writeinprog\30want\27relbuf\26dirty" \
251 "\25read\24raw\23phys\22clusterok\21malloc\20nocache" \
252 "\17locked\16inval\15scanned\14error\13eintr\12done\11freebuf" \
253 "\10delwri\7call\6cache\4direct\3async\2needcommit\1age"
254
255/*
256 * These flags are kept in b_xflags.
257 */
258#define BX_VNDIRTY 0x00000001 /* On vnode dirty list */
259#define BX_VNCLEAN 0x00000002 /* On vnode clean list */
260#define BX_BKGRDWRITE 0x00000004 /* Do writes in background */
261#define BX_BKGRDINPROG 0x00000008 /* Background write in progress */
262#define BX_BKGRDWAIT 0x00000010 /* Background write waiting */
263#define BX_AUTOCHAINDONE 0x00000020 /* pager I/O chain auto mode */
264
265#define NOOFFSET (-1LL) /* No buffer offset calculated yet */
266
267#ifdef _KERNEL
268/*
3020e3be 269 * Buffer locking. See sys/buf2.h for inline functions.
984263bc 270 */
3b1fced4 271extern struct lwkt_token buftimetoken; /* Interlock on setting prio and timo */
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272extern char *buf_wmesg; /* Default buffer lock message */
273#define BUF_WMESG "bufwait"
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274
275#endif /* _KERNEL */
276
277struct buf_queue_head {
278 TAILQ_HEAD(buf_queue, buf) queue;
279 daddr_t last_pblkno;
280 struct buf *insert_point;
281 struct buf *switch_point;
282};
283
284/*
285 * This structure describes a clustered I/O. It is stored in the b_saveaddr
286 * field of the buffer on which I/O is done. At I/O completion, cluster
287 * callback uses the structure to parcel I/O's to individual buffers, and
288 * then free's this structure.
289 */
290struct cluster_save {
291 long bs_bcount; /* Saved b_bcount. */
292 long bs_bufsize; /* Saved b_bufsize. */
293 void *bs_saveaddr; /* Saved b_addr. */
294 int bs_nchildren; /* Number of associated buffers. */
295 struct buf **bs_children; /* List of associated buffers. */
296};
297
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298/*
299 * Definitions for the buffer free lists.
300 */
301#define BUFFER_QUEUES 6 /* number of free buffer queues */
302
303#define QUEUE_NONE 0 /* on no queue */
304#define QUEUE_LOCKED 1 /* locked buffers */
305#define QUEUE_CLEAN 2 /* non-B_DELWRI buffers */
306#define QUEUE_DIRTY 3 /* B_DELWRI buffers */
307#define QUEUE_EMPTYKVA 4 /* empty buffer headers w/KVA assignment */
308#define QUEUE_EMPTY 5 /* empty buffer headers */
309
310/*
311 * Zero out the buffer's data area.
312 */
313#define clrbuf(bp) { \
314 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
315 (bp)->b_resid = 0; \
316}
317
318/*
319 * Flags to low-level bitmap allocation routines (balloc).
320 *
321 * Note: sequential_heuristic() in kern/vfs_vnops.c limits the count
322 * to 127.
323 */
324#define B_SEQMASK 0x7F000000 /* Sequential heuristic mask. */
325#define B_SEQSHIFT 24 /* Sequential heuristic shift. */
326#define B_SEQMAX 0x7F
327#define B_CLRBUF 0x01 /* Cleared invalid areas of buffer. */
328#define B_SYNC 0x02 /* Do all allocations synchronously. */
329
330#ifdef _KERNEL
331extern int nbuf; /* The number of buffer headers */
332extern int maxswzone; /* Max KVA for swap structures */
333extern int maxbcache; /* Max KVA for buffer cache */
334extern int runningbufspace;
335extern int buf_maxio; /* nominal maximum I/O for buffer */
336extern struct buf *buf; /* The buffer headers. */
337extern char *buffers; /* The buffer contents. */
338extern int bufpages; /* Number of memory pages in the buffer pool. */
339extern struct buf *swbuf; /* Swap I/O buffer headers. */
340extern int nswbuf; /* Number of swap I/O buffer headers. */
341extern TAILQ_HEAD(swqueue, buf) bswlist;
342extern TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES];
343
344struct uio;
345
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346caddr_t bufhashinit (caddr_t);
347void bufinit (void);
348void bwillwrite (void);
349int buf_dirty_count_severe (void);
350void bremfree (struct buf *);
351int bread (struct vnode *, daddr_t, int, struct buf **);
352int breadn (struct vnode *, daddr_t, int, daddr_t *, int *, int,
353 struct buf **);
354int bwrite (struct buf *);
355void bdwrite (struct buf *);
356void bawrite (struct buf *);
357void bdirty (struct buf *);
358void bundirty (struct buf *);
359int bowrite (struct buf *);
360void brelse (struct buf *);
361void bqrelse (struct buf *);
362int vfs_bio_awrite (struct buf *);
363struct buf * getpbuf (int *);
364struct buf *incore (struct vnode *, daddr_t);
365struct buf *gbincore (struct vnode *, daddr_t);
366int inmem (struct vnode *, daddr_t);
367struct buf *getblk (struct vnode *, daddr_t, int, int, int);
368struct buf *geteblk (int);
369int biowait (struct buf *);
370void biodone (struct buf *);
984263bc 371
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372void cluster_callback (struct buf *);
373int cluster_read (struct vnode *, u_quad_t, daddr_t, long,
374 long, int, struct buf **);
375int cluster_wbuild (struct vnode *, long, daddr_t, int);
376void cluster_write (struct buf *, u_quad_t, int);
377int physio (dev_t dev, struct uio *uio, int ioflag);
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378#define physread physio
379#define physwrite physio
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380void vfs_bio_set_validclean (struct buf *, int base, int size);
381void vfs_bio_clrbuf (struct buf *);
382void vfs_busy_pages (struct buf *, int clear_modify);
383void vfs_unbusy_pages (struct buf *);
384void vwakeup (struct buf *);
385int vmapbuf (struct buf *);
386void vunmapbuf (struct buf *);
387void relpbuf (struct buf *, int *);
388void brelvp (struct buf *);
389void bgetvp (struct vnode *, struct buf *);
390void pbgetvp (struct vnode *, struct buf *);
391void pbrelvp (struct buf *);
392int allocbuf (struct buf *bp, int size);
393void reassignbuf (struct buf *, struct vnode *);
394void pbreassignbuf (struct buf *, struct vnode *);
395struct buf *trypbuf (int *);
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396
397#endif /* _KERNEL */
398
399#endif /* !_SYS_BUF_H_ */