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[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 $
bb3e0be6 40 * $DragonFly: src/sys/sys/buf.h,v 1.18 2005/08/08 16:53:12 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
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59#ifndef _SYS_TREE_H_
60#include <sys/tree.h>
61#endif
54f51aeb 62
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63#ifndef _SYS_BIO_H_
64#include <sys/bio.h>
65#endif
66
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67struct buf;
68struct mount;
69struct vnode;
54f51aeb 70struct xio;
984263bc 71
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72struct buf_rb_tree;
73RB_PROTOTYPE(buf_rb_tree, buf, b_rbnode, rb_buf_compare);
74
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75/*
76 * To avoid including <ufs/ffs/softdep.h>
77 */
78LIST_HEAD(workhead, worklist);
79/*
80 * These are currently used only by the soft dependency code, hence
81 * are stored once in a global variable. If other subsystems wanted
82 * to use these hooks, a pointer to a set of bio_ops could be added
83 * to each buffer.
84 */
85extern struct bio_ops {
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86 void (*io_start) (struct buf *);
87 void (*io_complete) (struct buf *);
88 void (*io_deallocate) (struct buf *);
89 int (*io_fsync) (struct vnode *);
90 int (*io_sync) (struct mount *);
91 void (*io_movedeps) (struct buf *, struct buf *);
92 int (*io_countdeps) (struct buf *, int);
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93} bioops;
94
95struct iodone_chain {
96 long ic_prev_flags;
b153f746 97 void (*ic_prev_iodone) (struct buf *);
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98 void *ic_prev_iodone_chain;
99 struct {
100 long ia_long;
101 void *ia_ptr;
102 } ic_args[5];
103};
104
105/*
106 * The buffer header describes an I/O operation in the kernel.
107 *
108 * NOTES:
109 * b_bufsize, b_bcount. b_bufsize is the allocation size of the
110 * buffer, either DEV_BSIZE or PAGE_SIZE aligned. b_bcount is the
111 * originally requested buffer size and can serve as a bounds check
112 * against EOF. For most, but not all uses, b_bcount == b_bufsize.
113 *
114 * b_dirtyoff, b_dirtyend. Buffers support piecemeal, unaligned
115 * ranges of dirty data that need to be written to backing store.
116 * The range is typically clipped at b_bcount ( not b_bufsize ).
117 *
118 * b_resid. Number of bytes remaining in I/O. After an I/O operation
119 * completes, b_resid is usually 0 indicating 100% success.
120 */
121struct buf {
122 LIST_ENTRY(buf) b_hash; /* Hash chain. */
6bae6177 123 RB_ENTRY(buf) b_rbnode; /* Red-Black node in vnode RB tree */
984263bc 124 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
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125 TAILQ_ENTRY(buf) b_act; /* driver queue when active. *new* */
126 struct bio b_bio; /* Underlying I/O */
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127 long b_flags; /* B_* flags. */
128 unsigned short b_qindex; /* buffer queue index */
129 unsigned char b_xflags; /* extra flags */
130 struct lock b_lock; /* Buffer lock */
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131 long b_bufsize; /* Allocated buffer size. */
132 long b_runningbufspace; /* when I/O is running, pipelining */
133 long b_bcount; /* Valid bytes in buffer. */
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134 caddr_t b_data; /* Memory, superblocks, indirect etc. */
135 caddr_t b_kvabase; /* base kva for buffer */
136 int b_kvasize; /* size of kva for buffer */
984263bc 137 off_t b_offset; /* Offset into file */
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138 /* For nested b_iodone's. */
139 struct iodone_chain *b_iodone_chain;
140 struct vnode *b_vp; /* Device vnode. */
141 int b_dirtyoff; /* Offset in buffer of dirty region. */
142 int b_dirtyend; /* Offset of end of dirty region. */
984263bc 143 void *b_saveaddr; /* Original b_addr for physio. */
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144 union pager_info {
145 void *pg_spc;
146 int pg_reqpage;
147 } b_pager;
148 union cluster_info {
149 TAILQ_HEAD(cluster_list_head, buf) cluster_head;
150 TAILQ_ENTRY(buf) cluster_entry;
151 } b_cluster;
837ddd46 152 struct xio b_xio; /* page list management for buffer head. */
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153 struct workhead b_dep; /* List of filesystem dependencies. */
154 struct chain_info { /* buffer chaining */
155 struct buf *parent;
156 int count;
157 } b_chain;
158};
159
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160#define b_dev b_bio.bio_dev
161#define b_resid b_bio.bio_resid
162#define b_error b_bio.bio_error
163#define b_lblkno b_bio.bio_lblkno
164#define b_blkno b_bio.bio_blkno
165#define b_pblkno b_bio.bio_pblkno
166#define b_driver1 b_bio.bio_driver_ctx
167#define b_caller1 b_bio.bio_caller_ctx
168#define b_iodone b_bio.bio_done
169#define b_spc b_pager.pg_spc
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170
171/*
172 * These flags are kept in b_flags.
173 *
174 * Notes:
175 *
176 * B_ASYNC VOP calls on bp's are usually async whether or not
177 * B_ASYNC is set, but some subsystems, such as NFS, like
178 * to know what is best for the caller so they can
179 * optimize the I/O.
180 *
181 * B_PAGING Indicates that bp is being used by the paging system or
182 * some paging system and that the bp is not linked into
183 * the b_vp's clean/dirty linked lists or ref counts.
184 * Buffer vp reassignments are illegal in this case.
185 *
186 * B_CACHE This may only be set if the buffer is entirely valid.
187 * The situation where B_DELWRI is set and B_CACHE is
188 * clear MUST be committed to disk by getblk() so
189 * B_DELWRI can also be cleared. See the comments for
190 * getblk() in kern/vfs_bio.c. If B_CACHE is clear,
191 * the caller is expected to clear B_ERROR|B_INVAL,
192 * set B_READ, and initiate an I/O.
193 *
194 * The 'entire buffer' is defined to be the range from
195 * 0 through b_bcount.
196 *
197 * B_MALLOC Request that the buffer be allocated from the malloc
198 * pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
199 *
200 * B_CLUSTEROK This flag is typically set for B_DELWRI buffers
201 * by filesystems that allow clustering when the buffer
202 * is fully dirty and indicates that it may be clustered
203 * with other adjacent dirty buffers. Note the clustering
204 * may not be used with the stage 1 data write under NFS
205 * but may be used for the commit rpc portion.
206 *
207 * B_VMIO Indicates that the buffer is tied into an VM object.
208 * The buffer's data is always PAGE_SIZE aligned even
209 * if b_bufsize and b_bcount are not. ( b_bufsize is
210 * always at least DEV_BSIZE aligned, though ).
211 *
212 * B_DIRECT Hint that we should attempt to completely free
213 * the pages underlying the buffer. B_DIRECT is
214 * sticky until the buffer is released and typically
215 * only has an effect when B_RELBUF is also set.
216 *
217 * B_NOWDRAIN This flag should be set when a device (like VN)
218 * does a turn-around VOP_WRITE from its strategy
219 * routine. This flag prevents bwrite() from blocking
220 * in wdrain, avoiding a deadlock situation.
221 */
222
223#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
224#define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
225#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
226#define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */
227#define B_DEFERRED 0x00000010 /* Skipped over for cleaning */
228#define B_CACHE 0x00000020 /* Bread found us in the cache. */
71bc1d95 229#define B_UNUSED40 0x00000040 /* Unused */
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230#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
231#define B_FREEBUF 0x00000100 /* Instruct driver: free blocks */
232#define B_DONE 0x00000200 /* I/O completed. */
233#define B_EINTR 0x00000400 /* I/O was interrupted */
234#define B_ERROR 0x00000800 /* I/O error occurred. */
71bc1d95 235#define B_UNUSED1000 0x00001000 /* Unused */
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236#define B_INVAL 0x00002000 /* Does not contain valid info. */
237#define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
238#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
239#define B_MALLOC 0x00010000 /* malloced b_data */
240#define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
241#define B_PHYS 0x00040000 /* I/O to user memory. */
242#define B_RAW 0x00080000 /* Set by physio for raw transfers. */
243#define B_READ 0x00100000 /* Read buffer. */
244#define B_DIRTY 0x00200000 /* Needs writing later. */
245#define B_RELBUF 0x00400000 /* Release VMIO buffer. */
246#define B_WANT 0x00800000 /* Used by vm_pager.c */
247#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
71bc1d95 248#define B_UNUSED1000000 0x01000000 /* Unused */
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249#define B_XXX 0x02000000 /* Debugging flag. */
250#define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
251#define B_ORDERED 0x08000000 /* Must guarantee I/O ordering */
252#define B_RAM 0x10000000 /* Read ahead mark (flag) */
253#define B_VMIO 0x20000000 /* VMIO flag */
254#define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
255#define B_NOWDRAIN 0x80000000 /* Avoid wdrain deadlock */
256
257#define PRINT_BUF_FLAGS "\20\40nowdrain\37cluster\36vmio\35ram\34ordered" \
258 "\33paging\32xxx\31writeinprog\30want\27relbuf\26dirty" \
259 "\25read\24raw\23phys\22clusterok\21malloc\20nocache" \
260 "\17locked\16inval\15scanned\14error\13eintr\12done\11freebuf" \
261 "\10delwri\7call\6cache\4direct\3async\2needcommit\1age"
262
263/*
264 * These flags are kept in b_xflags.
265 */
266#define BX_VNDIRTY 0x00000001 /* On vnode dirty list */
267#define BX_VNCLEAN 0x00000002 /* On vnode clean list */
268#define BX_BKGRDWRITE 0x00000004 /* Do writes in background */
269#define BX_BKGRDINPROG 0x00000008 /* Background write in progress */
270#define BX_BKGRDWAIT 0x00000010 /* Background write waiting */
271#define BX_AUTOCHAINDONE 0x00000020 /* pager I/O chain auto mode */
272
273#define NOOFFSET (-1LL) /* No buffer offset calculated yet */
274
275#ifdef _KERNEL
276/*
3020e3be 277 * Buffer locking. See sys/buf2.h for inline functions.
984263bc 278 */
3b1fced4 279extern struct lwkt_token buftimetoken; /* Interlock on setting prio and timo */
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280extern char *buf_wmesg; /* Default buffer lock message */
281#define BUF_WMESG "bufwait"
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282
283#endif /* _KERNEL */
284
285struct buf_queue_head {
286 TAILQ_HEAD(buf_queue, buf) queue;
287 daddr_t last_pblkno;
288 struct buf *insert_point;
289 struct buf *switch_point;
290};
291
292/*
293 * This structure describes a clustered I/O. It is stored in the b_saveaddr
294 * field of the buffer on which I/O is done. At I/O completion, cluster
295 * callback uses the structure to parcel I/O's to individual buffers, and
296 * then free's this structure.
297 */
298struct cluster_save {
299 long bs_bcount; /* Saved b_bcount. */
300 long bs_bufsize; /* Saved b_bufsize. */
301 void *bs_saveaddr; /* Saved b_addr. */
302 int bs_nchildren; /* Number of associated buffers. */
303 struct buf **bs_children; /* List of associated buffers. */
304};
305
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306/*
307 * Zero out the buffer's data area.
308 */
309#define clrbuf(bp) { \
310 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
311 (bp)->b_resid = 0; \
312}
313
314/*
315 * Flags to low-level bitmap allocation routines (balloc).
316 *
317 * Note: sequential_heuristic() in kern/vfs_vnops.c limits the count
318 * to 127.
319 */
320#define B_SEQMASK 0x7F000000 /* Sequential heuristic mask. */
321#define B_SEQSHIFT 24 /* Sequential heuristic shift. */
322#define B_SEQMAX 0x7F
323#define B_CLRBUF 0x01 /* Cleared invalid areas of buffer. */
324#define B_SYNC 0x02 /* Do all allocations synchronously. */
325
326#ifdef _KERNEL
327extern int nbuf; /* The number of buffer headers */
328extern int maxswzone; /* Max KVA for swap structures */
329extern int maxbcache; /* Max KVA for buffer cache */
330extern int runningbufspace;
331extern int buf_maxio; /* nominal maximum I/O for buffer */
332extern struct buf *buf; /* The buffer headers. */
333extern char *buffers; /* The buffer contents. */
334extern int bufpages; /* Number of memory pages in the buffer pool. */
335extern struct buf *swbuf; /* Swap I/O buffer headers. */
336extern int nswbuf; /* Number of swap I/O buffer headers. */
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337
338struct uio;
339
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340caddr_t bufhashinit (caddr_t);
341void bufinit (void);
342void bwillwrite (void);
343int buf_dirty_count_severe (void);
344void bremfree (struct buf *);
345int bread (struct vnode *, daddr_t, int, struct buf **);
346int breadn (struct vnode *, daddr_t, int, daddr_t *, int *, int,
347 struct buf **);
348int bwrite (struct buf *);
349void bdwrite (struct buf *);
350void bawrite (struct buf *);
351void bdirty (struct buf *);
352void bundirty (struct buf *);
353int bowrite (struct buf *);
354void brelse (struct buf *);
355void bqrelse (struct buf *);
356int vfs_bio_awrite (struct buf *);
357struct buf * getpbuf (int *);
358struct buf *incore (struct vnode *, daddr_t);
359struct buf *gbincore (struct vnode *, daddr_t);
360int inmem (struct vnode *, daddr_t);
361struct buf *getblk (struct vnode *, daddr_t, int, int, int);
362struct buf *geteblk (int);
363int biowait (struct buf *);
364void biodone (struct buf *);
984263bc 365
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366void cluster_callback (struct buf *);
367int cluster_read (struct vnode *, u_quad_t, daddr_t, long,
368 long, int, struct buf **);
369int cluster_wbuild (struct vnode *, long, daddr_t, int);
370void cluster_write (struct buf *, u_quad_t, int);
371int physio (dev_t dev, struct uio *uio, int ioflag);
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372#define physread physio
373#define physwrite physio
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374void vfs_bio_set_validclean (struct buf *, int base, int size);
375void vfs_bio_clrbuf (struct buf *);
376void vfs_busy_pages (struct buf *, int clear_modify);
377void vfs_unbusy_pages (struct buf *);
378void vwakeup (struct buf *);
379int vmapbuf (struct buf *);
380void vunmapbuf (struct buf *);
381void relpbuf (struct buf *, int *);
382void brelvp (struct buf *);
383void bgetvp (struct vnode *, struct buf *);
384void pbgetvp (struct vnode *, struct buf *);
385void pbrelvp (struct buf *);
386int allocbuf (struct buf *bp, int size);
387void reassignbuf (struct buf *, struct vnode *);
388void pbreassignbuf (struct buf *, struct vnode *);
389struct buf *trypbuf (int *);
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390
391#endif /* _KERNEL */
392
393#endif /* !_SYS_BUF_H_ */