Unlock vnodes prior to issuing VOP_NREMOVE to accomodate filesystem
[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 $
65c6c519 40 * $DragonFly: src/sys/sys/buf.h,v 1.23 2006/03/02 19:26:17 dillon 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
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62#ifndef _SYS_BIO_H_
63#include <sys/bio.h>
64#endif
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65#ifndef _SYS_SPINLOCK_H_
66#include <sys/spinlock.h>
67#endif
1eabbf32 68
984263bc 69struct buf;
81b5c339 70struct bio;
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71struct mount;
72struct vnode;
54f51aeb 73struct xio;
984263bc 74
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75#define NBUF_BIO 4
76
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77struct buf_rb_tree;
78RB_PROTOTYPE(buf_rb_tree, buf, b_rbnode, rb_buf_compare);
79
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80/*
81 * To avoid including <ufs/ffs/softdep.h>
82 */
83LIST_HEAD(workhead, worklist);
84/*
85 * These are currently used only by the soft dependency code, hence
86 * are stored once in a global variable. If other subsystems wanted
87 * to use these hooks, a pointer to a set of bio_ops could be added
88 * to each buffer.
89 */
90extern struct bio_ops {
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91 void (*io_start) (struct buf *);
92 void (*io_complete) (struct buf *);
93 void (*io_deallocate) (struct buf *);
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94 int (*io_fsync) (struct vnode *);
95 int (*io_sync) (struct mount *);
b153f746 96 void (*io_movedeps) (struct buf *, struct buf *);
1e5a0c40 97 int (*io_countdeps) (struct buf *, int);
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98} bioops;
99
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100/*
101 * The buffer header describes an I/O operation in the kernel.
102 *
103 * NOTES:
104 * b_bufsize, b_bcount. b_bufsize is the allocation size of the
105 * buffer, either DEV_BSIZE or PAGE_SIZE aligned. b_bcount is the
106 * originally requested buffer size and can serve as a bounds check
107 * against EOF. For most, but not all uses, b_bcount == b_bufsize.
108 *
109 * b_dirtyoff, b_dirtyend. Buffers support piecemeal, unaligned
110 * ranges of dirty data that need to be written to backing store.
111 * The range is typically clipped at b_bcount ( not b_bufsize ).
112 *
113 * b_resid. Number of bytes remaining in I/O. After an I/O operation
114 * completes, b_resid is usually 0 indicating 100% success.
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115 *
116 * b_bio1 and b_bio2 represent the two primary I/O layers. Additional
117 * I/O layers are allocated out of the object cache and may also exist.
118 *
119 * b_bio1 is the logical layer and contains offset or block number
120 * data for the primary vnode, b_vp. I/O operations are almost
121 * universally initiated from the logical layer, so you will often
122 * see things like: vn_strategy(bp->b_vp, &bp->b_bio1).
123 *
124 * b_bio2 is the first physical layer (typically the slice-relative
125 * layer) and contains the translated offset or block number for
126 * the block device underlying a filesystem. Filesystems such as UFS
127 * will maintain cached translations and you may see them initiate
128 * a 'physical' I/O using vn_strategy(devvp, &bp->b_bio2). BUT,
129 * remember that the layering is relative to bp->b_vp, so the
130 * device-relative block numbers for buffer cache operations that occur
131 * directly on a block device will be in the first BIO layer.
132 *
133 * NOTE!!! Only the BIO subsystem accesses b_bio1 and b_bio2 directly.
134 * ALL STRATEGY LAYERS FOR BOTH VNODES AND DEVICES ONLY ACCESS THE BIO
135 * PASSED TO THEM, AND WILL PUSH ANOTHER BIO LAYER IF FORWARDING THE
136 * I/O DEEPER. In particular, a vn_strategy() or dev_dstrategy()
137 * call should not ever access buf->b_vp as this vnode may be totally
138 * unrelated to the vnode/device whos strategy routine was called.
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139 */
140struct buf {
141 LIST_ENTRY(buf) b_hash; /* Hash chain. */
6bae6177 142 RB_ENTRY(buf) b_rbnode; /* Red-Black node in vnode RB tree */
984263bc 143 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
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144 struct buf *b_cluster_next; /* Next buffer (cluster code) */
145 struct vnode *b_vp; /* (vp, lblkno) index */
146 struct bio b_bio_array[NBUF_BIO]; /* BIO translation layers */
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147 long b_flags; /* B_* flags. */
148 unsigned short b_qindex; /* buffer queue index */
149 unsigned char b_xflags; /* extra flags */
150 struct lock b_lock; /* Buffer lock */
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151 long b_bufsize; /* Allocated buffer size. */
152 long b_runningbufspace; /* when I/O is running, pipelining */
153 long b_bcount; /* Valid bytes in buffer. */
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154 long b_resid; /* Remaining I/O */
155 int b_error; /* Error return */
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156 caddr_t b_data; /* Memory, superblocks, indirect etc. */
157 caddr_t b_kvabase; /* base kva for buffer */
158 int b_kvasize; /* size of kva for buffer */
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159 int b_dirtyoff; /* Offset in buffer of dirty region. */
160 int b_dirtyend; /* Offset of end of dirty region. */
984263bc 161 void *b_saveaddr; /* Original b_addr for physio. */
81b5c339 162 struct xio b_xio; /* data buffer page list management */
984263bc 163 struct workhead b_dep; /* List of filesystem dependencies. */
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164};
165
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166/*
167 * XXX temporary
168 */
169#define b_bio1 b_bio_array[0] /* logical layer */
170#define b_bio2 b_bio_array[1] /* (typically) the disk layer */
171#define b_loffset b_bio1.bio_offset
172#define b_lblkno b_bio1.bio_blkno
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173
174/*
175 * These flags are kept in b_flags.
176 *
177 * Notes:
178 *
179 * B_ASYNC VOP calls on bp's are usually async whether or not
180 * B_ASYNC is set, but some subsystems, such as NFS, like
181 * to know what is best for the caller so they can
182 * optimize the I/O.
183 *
184 * B_PAGING Indicates that bp is being used by the paging system or
185 * some paging system and that the bp is not linked into
186 * the b_vp's clean/dirty linked lists or ref counts.
187 * Buffer vp reassignments are illegal in this case.
188 *
189 * B_CACHE This may only be set if the buffer is entirely valid.
190 * The situation where B_DELWRI is set and B_CACHE is
191 * clear MUST be committed to disk by getblk() so
192 * B_DELWRI can also be cleared. See the comments for
193 * getblk() in kern/vfs_bio.c. If B_CACHE is clear,
194 * the caller is expected to clear B_ERROR|B_INVAL,
195 * set B_READ, and initiate an I/O.
196 *
197 * The 'entire buffer' is defined to be the range from
198 * 0 through b_bcount.
199 *
200 * B_MALLOC Request that the buffer be allocated from the malloc
201 * pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
202 *
203 * B_CLUSTEROK This flag is typically set for B_DELWRI buffers
204 * by filesystems that allow clustering when the buffer
205 * is fully dirty and indicates that it may be clustered
206 * with other adjacent dirty buffers. Note the clustering
207 * may not be used with the stage 1 data write under NFS
208 * but may be used for the commit rpc portion.
209 *
210 * B_VMIO Indicates that the buffer is tied into an VM object.
211 * The buffer's data is always PAGE_SIZE aligned even
212 * if b_bufsize and b_bcount are not. ( b_bufsize is
213 * always at least DEV_BSIZE aligned, though ).
214 *
215 * B_DIRECT Hint that we should attempt to completely free
216 * the pages underlying the buffer. B_DIRECT is
217 * sticky until the buffer is released and typically
218 * only has an effect when B_RELBUF is also set.
219 *
220 * B_NOWDRAIN This flag should be set when a device (like VN)
221 * does a turn-around VOP_WRITE from its strategy
222 * routine. This flag prevents bwrite() from blocking
223 * in wdrain, avoiding a deadlock situation.
224 */
225
226#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
227#define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
228#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
229#define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */
230#define B_DEFERRED 0x00000010 /* Skipped over for cleaning */
231#define B_CACHE 0x00000020 /* Bread found us in the cache. */
1e5a0c40 232#define B_UNUSED40 0x00000040 /* Unused */
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233#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
234#define B_FREEBUF 0x00000100 /* Instruct driver: free blocks */
235#define B_DONE 0x00000200 /* I/O completed. */
236#define B_EINTR 0x00000400 /* I/O was interrupted */
237#define B_ERROR 0x00000800 /* I/O error occurred. */
71bc1d95 238#define B_UNUSED1000 0x00001000 /* Unused */
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239#define B_INVAL 0x00002000 /* Does not contain valid info. */
240#define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
241#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
242#define B_MALLOC 0x00010000 /* malloced b_data */
243#define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
244#define B_PHYS 0x00040000 /* I/O to user memory. */
245#define B_RAW 0x00080000 /* Set by physio for raw transfers. */
246#define B_READ 0x00100000 /* Read buffer. */
247#define B_DIRTY 0x00200000 /* Needs writing later. */
248#define B_RELBUF 0x00400000 /* Release VMIO buffer. */
249#define B_WANT 0x00800000 /* Used by vm_pager.c */
250#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
71bc1d95 251#define B_UNUSED1000000 0x01000000 /* Unused */
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252#define B_XXX 0x02000000 /* Debugging flag. */
253#define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
254#define B_ORDERED 0x08000000 /* Must guarantee I/O ordering */
255#define B_RAM 0x10000000 /* Read ahead mark (flag) */
256#define B_VMIO 0x20000000 /* VMIO flag */
257#define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
258#define B_NOWDRAIN 0x80000000 /* Avoid wdrain deadlock */
259
260#define PRINT_BUF_FLAGS "\20\40nowdrain\37cluster\36vmio\35ram\34ordered" \
261 "\33paging\32xxx\31writeinprog\30want\27relbuf\26dirty" \
262 "\25read\24raw\23phys\22clusterok\21malloc\20nocache" \
263 "\17locked\16inval\15scanned\14error\13eintr\12done\11freebuf" \
264 "\10delwri\7call\6cache\4direct\3async\2needcommit\1age"
265
266/*
267 * These flags are kept in b_xflags.
268 */
269#define BX_VNDIRTY 0x00000001 /* On vnode dirty list */
270#define BX_VNCLEAN 0x00000002 /* On vnode clean list */
271#define BX_BKGRDWRITE 0x00000004 /* Do writes in background */
272#define BX_BKGRDINPROG 0x00000008 /* Background write in progress */
273#define BX_BKGRDWAIT 0x00000010 /* Background write waiting */
274#define BX_AUTOCHAINDONE 0x00000020 /* pager I/O chain auto mode */
275
276#define NOOFFSET (-1LL) /* No buffer offset calculated yet */
277
278#ifdef _KERNEL
279/*
3020e3be 280 * Buffer locking. See sys/buf2.h for inline functions.
984263bc 281 */
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282extern char *buf_wmesg; /* Default buffer lock message */
283#define BUF_WMESG "bufwait"
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284
285#endif /* _KERNEL */
286
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287struct bio_queue_head {
288 TAILQ_HEAD(bio_queue, bio) queue;
289 daddr_t last_blkno;
290 struct bio *insert_point;
291 struct bio *switch_point;
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292};
293
294/*
295 * This structure describes a clustered I/O. It is stored in the b_saveaddr
296 * field of the buffer on which I/O is done. At I/O completion, cluster
297 * callback uses the structure to parcel I/O's to individual buffers, and
298 * then free's this structure.
299 */
300struct cluster_save {
301 long bs_bcount; /* Saved b_bcount. */
302 long bs_bufsize; /* Saved b_bufsize. */
303 void *bs_saveaddr; /* Saved b_addr. */
304 int bs_nchildren; /* Number of associated buffers. */
305 struct buf **bs_children; /* List of associated buffers. */
306};
307
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308/*
309 * Zero out the buffer's data area.
310 */
311#define clrbuf(bp) { \
312 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
313 (bp)->b_resid = 0; \
314}
315
316/*
317 * Flags to low-level bitmap allocation routines (balloc).
318 *
319 * Note: sequential_heuristic() in kern/vfs_vnops.c limits the count
320 * to 127.
321 */
322#define B_SEQMASK 0x7F000000 /* Sequential heuristic mask. */
323#define B_SEQSHIFT 24 /* Sequential heuristic shift. */
324#define B_SEQMAX 0x7F
325#define B_CLRBUF 0x01 /* Cleared invalid areas of buffer. */
326#define B_SYNC 0x02 /* Do all allocations synchronously. */
327
328#ifdef _KERNEL
329extern int nbuf; /* The number of buffer headers */
330extern int maxswzone; /* Max KVA for swap structures */
331extern int maxbcache; /* Max KVA for buffer cache */
332extern int runningbufspace;
333extern int buf_maxio; /* nominal maximum I/O for buffer */
334extern struct buf *buf; /* The buffer headers. */
335extern char *buffers; /* The buffer contents. */
336extern int bufpages; /* Number of memory pages in the buffer pool. */
337extern struct buf *swbuf; /* Swap I/O buffer headers. */
338extern int nswbuf; /* Number of swap I/O buffer headers. */
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339
340struct uio;
341
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342caddr_t bufhashinit (caddr_t);
343void bufinit (void);
344void bwillwrite (void);
345int buf_dirty_count_severe (void);
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346void initbufbio(struct buf *);
347void reinitbufbio(struct buf *);
348void clearbiocache(struct bio *);
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349void bremfree (struct buf *);
350int bread (struct vnode *, daddr_t, int, struct buf **);
351int breadn (struct vnode *, daddr_t, int, daddr_t *, int *, int,
352 struct buf **);
353int bwrite (struct buf *);
354void bdwrite (struct buf *);
355void bawrite (struct buf *);
356void bdirty (struct buf *);
357void bundirty (struct buf *);
358int bowrite (struct buf *);
359void brelse (struct buf *);
360void bqrelse (struct buf *);
361int vfs_bio_awrite (struct buf *);
81b5c339 362struct buf *getpbuf (int *);
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363struct buf *incore (struct vnode *, daddr_t);
364struct buf *gbincore (struct vnode *, daddr_t);
365int inmem (struct vnode *, daddr_t);
366struct buf *getblk (struct vnode *, daddr_t, int, int, int);
367struct buf *geteblk (int);
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368struct bio *push_bio(struct bio *);
369void pop_bio(struct bio *);
b153f746 370int biowait (struct buf *);
81b5c339 371void biodone (struct bio *);
984263bc 372
81b5c339 373void cluster_append(struct bio *, struct buf *);
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374int cluster_read (struct vnode *, u_quad_t, daddr_t, long,
375 long, int, struct buf **);
376int cluster_wbuild (struct vnode *, long, daddr_t, int);
377void cluster_write (struct buf *, u_quad_t, int);
378int physio (dev_t dev, struct uio *uio, int ioflag);
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379#define physread physio
380#define physwrite physio
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381void vfs_bio_set_validclean (struct buf *, int base, int size);
382void vfs_bio_clrbuf (struct buf *);
383void vfs_busy_pages (struct buf *, int clear_modify);
384void vfs_unbusy_pages (struct buf *);
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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_ */