2 * Copyright (c) 2004 Poul-Henning Kamp
3 * Copyright (c) 1994,1997 John S. Dyson
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * this file contains a new buffer I/O scheme implementing a coherent
30 * VM object and buffer cache scheme. Pains have been taken to make
31 * sure that the performance degradation associated with schemes such
32 * as this is not realized.
34 * Author: John S. Dyson
35 * Significant help during the development and debugging phases
36 * had been provided by David Greenman, also of the FreeBSD core team.
38 * see man buf(9) for more info.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/systm.h>
49 #include <sys/devicestat.h>
50 #include <sys/eventhandler.h>
51 #include <sys/limits.h>
53 #include <sys/malloc.h>
54 #include <sys/mount.h>
55 #include <sys/mutex.h>
56 #include <sys/kernel.h>
57 #include <sys/kthread.h>
59 #include <sys/resourcevar.h>
60 #include <sys/sysctl.h>
61 #include <sys/vmmeter.h>
62 #include <sys/vnode.h>
63 #include <geom/geom.h>
65 #include <vm/vm_param.h>
66 #include <vm/vm_kern.h>
67 #include <vm/vm_pageout.h>
68 #include <vm/vm_page.h>
69 #include <vm/vm_object.h>
70 #include <vm/vm_extern.h>
71 #include <vm/vm_map.h>
72 #include "opt_compat.h"
73 #include "opt_directio.h"
76 static MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer");
78 struct bio_ops bioops; /* I/O operation notification */
80 struct buf_ops buf_ops_bio = {
81 .bop_name = "buf_ops_bio",
82 .bop_write = bufwrite,
83 .bop_strategy = bufstrategy,
85 .bop_bdflush = bufbdflush,
89 * XXX buf is global because kern_shutdown.c and ffs_checkoverlap has
90 * carnal knowledge of buffers. This knowledge should be moved to vfs_bio.c.
92 struct buf *buf; /* buffer header pool */
94 static struct proc *bufdaemonproc;
96 static int inmem(struct vnode *vp, daddr_t blkno);
97 static void vm_hold_free_pages(struct buf *bp, vm_offset_t from,
99 static void vm_hold_load_pages(struct buf *bp, vm_offset_t from,
101 static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m);
102 static void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off,
104 static void vfs_clean_pages(struct buf *bp);
105 static void vfs_setdirty(struct buf *bp);
106 static void vfs_setdirty_locked_object(struct buf *bp);
107 static void vfs_vmio_release(struct buf *bp);
108 static int vfs_bio_clcheck(struct vnode *vp, int size,
109 daddr_t lblkno, daddr_t blkno);
110 static int buf_do_flush(struct vnode *vp);
111 static int flushbufqueues(struct vnode *, int, int);
112 static void buf_daemon(void);
113 static void bremfreel(struct buf *bp);
114 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
115 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
116 static int sysctl_bufspace(SYSCTL_HANDLER_ARGS);
119 int vmiodirenable = TRUE;
120 SYSCTL_INT(_vfs, OID_AUTO, vmiodirenable, CTLFLAG_RW, &vmiodirenable, 0,
121 "Use the VM system for directory writes");
122 long runningbufspace;
123 SYSCTL_LONG(_vfs, OID_AUTO, runningbufspace, CTLFLAG_RD, &runningbufspace, 0,
124 "Amount of presently outstanding async buffer io");
125 static long bufspace;
126 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
127 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
128 SYSCTL_PROC(_vfs, OID_AUTO, bufspace, CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RD,
129 &bufspace, 0, sysctl_bufspace, "L", "Virtual memory used for buffers");
131 SYSCTL_LONG(_vfs, OID_AUTO, bufspace, CTLFLAG_RD, &bufspace, 0,
132 "Virtual memory used for buffers");
134 static long maxbufspace;
135 SYSCTL_LONG(_vfs, OID_AUTO, maxbufspace, CTLFLAG_RD, &maxbufspace, 0,
136 "Maximum allowed value of bufspace (including buf_daemon)");
137 static long bufmallocspace;
138 SYSCTL_LONG(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0,
139 "Amount of malloced memory for buffers");
140 static long maxbufmallocspace;
141 SYSCTL_LONG(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace, 0,
142 "Maximum amount of malloced memory for buffers");
143 static long lobufspace;
144 SYSCTL_LONG(_vfs, OID_AUTO, lobufspace, CTLFLAG_RD, &lobufspace, 0,
145 "Minimum amount of buffers we want to have");
147 SYSCTL_LONG(_vfs, OID_AUTO, hibufspace, CTLFLAG_RD, &hibufspace, 0,
148 "Maximum allowed value of bufspace (excluding buf_daemon)");
149 static int bufreusecnt;
150 SYSCTL_INT(_vfs, OID_AUTO, bufreusecnt, CTLFLAG_RW, &bufreusecnt, 0,
151 "Number of times we have reused a buffer");
152 static int buffreekvacnt;
153 SYSCTL_INT(_vfs, OID_AUTO, buffreekvacnt, CTLFLAG_RW, &buffreekvacnt, 0,
154 "Number of times we have freed the KVA space from some buffer");
155 static int bufdefragcnt;
156 SYSCTL_INT(_vfs, OID_AUTO, bufdefragcnt, CTLFLAG_RW, &bufdefragcnt, 0,
157 "Number of times we have had to repeat buffer allocation to defragment");
158 static long lorunningspace;
159 SYSCTL_LONG(_vfs, OID_AUTO, lorunningspace, CTLFLAG_RW, &lorunningspace, 0,
160 "Minimum preferred space used for in-progress I/O");
161 static long hirunningspace;
162 SYSCTL_LONG(_vfs, OID_AUTO, hirunningspace, CTLFLAG_RW, &hirunningspace, 0,
163 "Maximum amount of space to use for in-progress I/O");
164 int dirtybufferflushes;
165 SYSCTL_INT(_vfs, OID_AUTO, dirtybufferflushes, CTLFLAG_RW, &dirtybufferflushes,
166 0, "Number of bdwrite to bawrite conversions to limit dirty buffers");
168 SYSCTL_INT(_vfs, OID_AUTO, bdwriteskip, CTLFLAG_RW, &bdwriteskip,
169 0, "Number of buffers supplied to bdwrite with snapshot deadlock risk");
170 int altbufferflushes;
171 SYSCTL_INT(_vfs, OID_AUTO, altbufferflushes, CTLFLAG_RW, &altbufferflushes,
172 0, "Number of fsync flushes to limit dirty buffers");
173 static int recursiveflushes;
174 SYSCTL_INT(_vfs, OID_AUTO, recursiveflushes, CTLFLAG_RW, &recursiveflushes,
175 0, "Number of flushes skipped due to being recursive");
176 static int numdirtybuffers;
177 SYSCTL_INT(_vfs, OID_AUTO, numdirtybuffers, CTLFLAG_RD, &numdirtybuffers, 0,
178 "Number of buffers that are dirty (has unwritten changes) at the moment");
179 static int lodirtybuffers;
180 SYSCTL_INT(_vfs, OID_AUTO, lodirtybuffers, CTLFLAG_RW, &lodirtybuffers, 0,
181 "How many buffers we want to have free before bufdaemon can sleep");
182 static int hidirtybuffers;
183 SYSCTL_INT(_vfs, OID_AUTO, hidirtybuffers, CTLFLAG_RW, &hidirtybuffers, 0,
184 "When the number of dirty buffers is considered severe");
186 SYSCTL_INT(_vfs, OID_AUTO, dirtybufthresh, CTLFLAG_RW, &dirtybufthresh,
187 0, "Number of bdwrite to bawrite conversions to clear dirty buffers");
188 static int numfreebuffers;
189 SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0,
190 "Number of free buffers");
191 static int lofreebuffers;
192 SYSCTL_INT(_vfs, OID_AUTO, lofreebuffers, CTLFLAG_RW, &lofreebuffers, 0,
194 static int hifreebuffers;
195 SYSCTL_INT(_vfs, OID_AUTO, hifreebuffers, CTLFLAG_RW, &hifreebuffers, 0,
196 "XXX Complicatedly unused");
197 static int getnewbufcalls;
198 SYSCTL_INT(_vfs, OID_AUTO, getnewbufcalls, CTLFLAG_RW, &getnewbufcalls, 0,
199 "Number of calls to getnewbuf");
200 static int getnewbufrestarts;
201 SYSCTL_INT(_vfs, OID_AUTO, getnewbufrestarts, CTLFLAG_RW, &getnewbufrestarts, 0,
202 "Number of times getnewbuf has had to restart a buffer aquisition");
203 static int flushbufqtarget = 100;
204 SYSCTL_INT(_vfs, OID_AUTO, flushbufqtarget, CTLFLAG_RW, &flushbufqtarget, 0,
205 "Amount of work to do in flushbufqueues when helping bufdaemon");
206 static long notbufdflashes;
207 SYSCTL_LONG(_vfs, OID_AUTO, notbufdflashes, CTLFLAG_RD, ¬bufdflashes, 0,
208 "Number of dirty buffer flushes done by the bufdaemon helpers");
211 * Wakeup point for bufdaemon, as well as indicator of whether it is already
212 * active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it
215 static int bd_request;
218 * This lock synchronizes access to bd_request.
220 static struct mtx bdlock;
223 * bogus page -- for I/O to/from partially complete buffers
224 * this is a temporary solution to the problem, but it is not
225 * really that bad. it would be better to split the buffer
226 * for input in the case of buffers partially already in memory,
227 * but the code is intricate enough already.
229 vm_page_t bogus_page;
232 * Synchronization (sleep/wakeup) variable for active buffer space requests.
233 * Set when wait starts, cleared prior to wakeup().
234 * Used in runningbufwakeup() and waitrunningbufspace().
236 static int runningbufreq;
239 * This lock protects the runningbufreq and synchronizes runningbufwakeup and
240 * waitrunningbufspace().
242 static struct mtx rbreqlock;
245 * Synchronization (sleep/wakeup) variable for buffer requests.
246 * Can contain the VFS_BIO_NEED flags defined below; setting/clearing is done
248 * Used in numdirtywakeup(), bufspacewakeup(), bufcountwakeup(), bwillwrite(),
249 * getnewbuf(), and getblk().
251 static int needsbuffer;
254 * Lock that protects needsbuffer and the sleeps/wakeups surrounding it.
256 static struct mtx nblock;
259 * Definitions for the buffer free lists.
261 #define BUFFER_QUEUES 6 /* number of free buffer queues */
263 #define QUEUE_NONE 0 /* on no queue */
264 #define QUEUE_CLEAN 1 /* non-B_DELWRI buffers */
265 #define QUEUE_DIRTY 2 /* B_DELWRI buffers */
266 #define QUEUE_DIRTY_GIANT 3 /* B_DELWRI buffers that need giant */
267 #define QUEUE_EMPTYKVA 4 /* empty buffer headers w/KVA assignment */
268 #define QUEUE_EMPTY 5 /* empty buffer headers */
269 #define QUEUE_SENTINEL 1024 /* not an queue index, but mark for sentinel */
271 /* Queues for free buffers with various properties */
272 static TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES] = { { 0 } };
274 /* Lock for the bufqueues */
275 static struct mtx bqlock;
278 * Single global constant for BUF_WMESG, to avoid getting multiple references.
279 * buf_wmesg is referred from macros.
281 const char *buf_wmesg = BUF_WMESG;
283 #define VFS_BIO_NEED_ANY 0x01 /* any freeable buffer */
284 #define VFS_BIO_NEED_DIRTYFLUSH 0x02 /* waiting for dirty buffer flush */
285 #define VFS_BIO_NEED_FREE 0x04 /* wait for free bufs, hi hysteresis */
286 #define VFS_BIO_NEED_BUFSPACE 0x08 /* wait for buf space, lo hysteresis */
288 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
289 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
291 sysctl_bufspace(SYSCTL_HANDLER_ARGS)
296 if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long))
297 return (sysctl_handle_long(oidp, arg1, arg2, req));
298 lvalue = *(long *)arg1;
299 if (lvalue > INT_MAX)
300 /* On overflow, still write out a long to trigger ENOMEM. */
301 return (sysctl_handle_long(oidp, &lvalue, 0, req));
303 return (sysctl_handle_int(oidp, &ivalue, 0, req));
308 extern void ffs_rawread_setup(void);
309 #endif /* DIRECTIO */
313 * If someone is blocked due to there being too many dirty buffers,
314 * and numdirtybuffers is now reasonable, wake them up.
318 numdirtywakeup(int level)
321 if (numdirtybuffers <= level) {
323 if (needsbuffer & VFS_BIO_NEED_DIRTYFLUSH) {
324 needsbuffer &= ~VFS_BIO_NEED_DIRTYFLUSH;
325 wakeup(&needsbuffer);
334 * Called when buffer space is potentially available for recovery.
335 * getnewbuf() will block on this flag when it is unable to free
336 * sufficient buffer space. Buffer space becomes recoverable when
337 * bp's get placed back in the queues.
345 * If someone is waiting for BUF space, wake them up. Even
346 * though we haven't freed the kva space yet, the waiting
347 * process will be able to now.
350 if (needsbuffer & VFS_BIO_NEED_BUFSPACE) {
351 needsbuffer &= ~VFS_BIO_NEED_BUFSPACE;
352 wakeup(&needsbuffer);
358 * runningbufwakeup() - in-progress I/O accounting.
362 runningbufwakeup(struct buf *bp)
365 if (bp->b_runningbufspace) {
366 atomic_subtract_long(&runningbufspace, bp->b_runningbufspace);
367 bp->b_runningbufspace = 0;
368 mtx_lock(&rbreqlock);
369 if (runningbufreq && runningbufspace <= lorunningspace) {
371 wakeup(&runningbufreq);
373 mtx_unlock(&rbreqlock);
380 * Called when a buffer has been added to one of the free queues to
381 * account for the buffer and to wakeup anyone waiting for free buffers.
382 * This typically occurs when large amounts of metadata are being handled
383 * by the buffer cache ( else buffer space runs out first, usually ).
390 atomic_add_int(&numfreebuffers, 1);
393 needsbuffer &= ~VFS_BIO_NEED_ANY;
394 if (numfreebuffers >= hifreebuffers)
395 needsbuffer &= ~VFS_BIO_NEED_FREE;
396 wakeup(&needsbuffer);
402 * waitrunningbufspace()
404 * runningbufspace is a measure of the amount of I/O currently
405 * running. This routine is used in async-write situations to
406 * prevent creating huge backups of pending writes to a device.
407 * Only asynchronous writes are governed by this function.
409 * Reads will adjust runningbufspace, but will not block based on it.
410 * The read load has a side effect of reducing the allowed write load.
412 * This does NOT turn an async write into a sync write. It waits
413 * for earlier writes to complete and generally returns before the
414 * caller's write has reached the device.
417 waitrunningbufspace(void)
420 mtx_lock(&rbreqlock);
421 while (runningbufspace > hirunningspace) {
423 msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0);
425 mtx_unlock(&rbreqlock);
430 * vfs_buf_test_cache:
432 * Called when a buffer is extended. This function clears the B_CACHE
433 * bit if the newly extended portion of the buffer does not contain
438 vfs_buf_test_cache(struct buf *bp,
439 vm_ooffset_t foff, vm_offset_t off, vm_offset_t size,
443 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
444 if (bp->b_flags & B_CACHE) {
445 int base = (foff + off) & PAGE_MASK;
446 if (vm_page_is_valid(m, base, size) == 0)
447 bp->b_flags &= ~B_CACHE;
451 /* Wake up the buffer daemon if necessary */
454 bd_wakeup(int dirtybuflevel)
458 if (bd_request == 0 && numdirtybuffers >= dirtybuflevel) {
466 * bd_speedup - speedup the buffer cache flushing code
478 * Calculating buffer cache scaling values and reserve space for buffer
479 * headers. This is called during low level kernel initialization and
480 * may be called more then once. We CANNOT write to the memory area
481 * being reserved at this time.
484 kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est)
490 * physmem_est is in pages. Convert it to kilobytes (assumes
491 * PAGE_SIZE is >= 1K)
493 physmem_est = physmem_est * (PAGE_SIZE / 1024);
496 * The nominal buffer size (and minimum KVA allocation) is BKVASIZE.
497 * For the first 64MB of ram nominally allocate sufficient buffers to
498 * cover 1/4 of our ram. Beyond the first 64MB allocate additional
499 * buffers to cover 1/10 of our ram over 64MB. When auto-sizing
500 * the buffer cache we limit the eventual kva reservation to
503 * factor represents the 1/4 x ram conversion.
506 int factor = 4 * BKVASIZE / 1024;
509 if (physmem_est > 4096)
510 nbuf += min((physmem_est - 4096) / factor,
512 if (physmem_est > 65536)
513 nbuf += (physmem_est - 65536) * 2 / (factor * 5);
515 if (maxbcache && nbuf > maxbcache / BKVASIZE)
516 nbuf = maxbcache / BKVASIZE;
521 /* XXX Avoid unsigned long overflows later on with maxbufspace. */
522 maxbuf = (LONG_MAX / 3) / BKVASIZE;
525 printf("Warning: nbufs lowered from %d to %ld\n", nbuf,
531 * swbufs are used as temporary holders for I/O, such as paging I/O.
532 * We have no less then 16 and no more then 256.
534 nswbuf = max(min(nbuf/4, 256), 16);
536 if (nswbuf < NSWBUF_MIN)
544 * Reserve space for the buffer cache buffers
547 v = (caddr_t)(swbuf + nswbuf);
549 v = (caddr_t)(buf + nbuf);
554 /* Initialize the buffer subsystem. Called before use of any buffers. */
561 mtx_init(&bqlock, "buf queue lock", NULL, MTX_DEF);
562 mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF);
563 mtx_init(&nblock, "needsbuffer lock", NULL, MTX_DEF);
564 mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF);
566 /* next, make a null set of free lists */
567 for (i = 0; i < BUFFER_QUEUES; i++)
568 TAILQ_INIT(&bufqueues[i]);
570 /* finally, initialize each buffer header and stick on empty q */
571 for (i = 0; i < nbuf; i++) {
573 bzero(bp, sizeof *bp);
574 bp->b_flags = B_INVAL; /* we're just an empty header */
575 bp->b_rcred = NOCRED;
576 bp->b_wcred = NOCRED;
577 bp->b_qindex = QUEUE_EMPTY;
580 LIST_INIT(&bp->b_dep);
582 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
586 * maxbufspace is the absolute maximum amount of buffer space we are
587 * allowed to reserve in KVM and in real terms. The absolute maximum
588 * is nominally used by buf_daemon. hibufspace is the nominal maximum
589 * used by most other processes. The differential is required to
590 * ensure that buf_daemon is able to run when other processes might
591 * be blocked waiting for buffer space.
593 * maxbufspace is based on BKVASIZE. Allocating buffers larger then
594 * this may result in KVM fragmentation which is not handled optimally
597 maxbufspace = (long)nbuf * BKVASIZE;
598 hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - MAXBSIZE * 10);
599 lobufspace = hibufspace - MAXBSIZE;
601 lorunningspace = 512 * 1024;
602 hirunningspace = 1024 * 1024;
605 * Limit the amount of malloc memory since it is wired permanently into
606 * the kernel space. Even though this is accounted for in the buffer
607 * allocation, we don't want the malloced region to grow uncontrolled.
608 * The malloc scheme improves memory utilization significantly on average
609 * (small) directories.
611 maxbufmallocspace = hibufspace / 20;
614 * Reduce the chance of a deadlock occuring by limiting the number
615 * of delayed-write dirty buffers we allow to stack up.
617 hidirtybuffers = nbuf / 4 + 20;
618 dirtybufthresh = hidirtybuffers * 9 / 10;
621 * To support extreme low-memory systems, make sure hidirtybuffers cannot
622 * eat up all available buffer space. This occurs when our minimum cannot
623 * be met. We try to size hidirtybuffers to 3/4 our buffer space assuming
624 * BKVASIZE'd (8K) buffers.
626 while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) {
627 hidirtybuffers >>= 1;
629 lodirtybuffers = hidirtybuffers / 2;
632 * Try to keep the number of free buffers in the specified range,
633 * and give special processes (e.g. like buf_daemon) access to an
636 lofreebuffers = nbuf / 18 + 5;
637 hifreebuffers = 2 * lofreebuffers;
638 numfreebuffers = nbuf;
641 * Maximum number of async ops initiated per buf_daemon loop. This is
642 * somewhat of a hack at the moment, we really need to limit ourselves
643 * based on the number of bytes of I/O in-transit that were initiated
647 bogus_page = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ |
648 VM_ALLOC_NORMAL | VM_ALLOC_WIRED);
652 * bfreekva() - free the kva allocation for a buffer.
654 * Since this call frees up buffer space, we call bufspacewakeup().
657 bfreekva(struct buf *bp)
661 atomic_add_int(&buffreekvacnt, 1);
662 atomic_subtract_long(&bufspace, bp->b_kvasize);
663 vm_map_remove(buffer_map, (vm_offset_t) bp->b_kvabase,
664 (vm_offset_t) bp->b_kvabase + bp->b_kvasize);
673 * Mark the buffer for removal from the appropriate free list in brelse.
677 bremfree(struct buf *bp)
680 CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
681 KASSERT((bp->b_flags & B_REMFREE) == 0,
682 ("bremfree: buffer %p already marked for delayed removal.", bp));
683 KASSERT(bp->b_qindex != QUEUE_NONE,
684 ("bremfree: buffer %p not on a queue.", bp));
687 bp->b_flags |= B_REMFREE;
688 /* Fixup numfreebuffers count. */
689 if ((bp->b_flags & B_INVAL) || (bp->b_flags & B_DELWRI) == 0)
690 atomic_subtract_int(&numfreebuffers, 1);
696 * Force an immediate removal from a free list. Used only in nfs when
697 * it abuses the b_freelist pointer.
700 bremfreef(struct buf *bp)
710 * Removes a buffer from the free list, must be called with the
714 bremfreel(struct buf *bp)
716 CTR3(KTR_BUF, "bremfreel(%p) vp %p flags %X",
717 bp, bp->b_vp, bp->b_flags);
718 KASSERT(bp->b_qindex != QUEUE_NONE,
719 ("bremfreel: buffer %p not on a queue.", bp));
721 mtx_assert(&bqlock, MA_OWNED);
723 TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist);
724 bp->b_qindex = QUEUE_NONE;
726 * If this was a delayed bremfree() we only need to remove the buffer
727 * from the queue and return the stats are already done.
729 if (bp->b_flags & B_REMFREE) {
730 bp->b_flags &= ~B_REMFREE;
734 * Fixup numfreebuffers count. If the buffer is invalid or not
735 * delayed-write, the buffer was free and we must decrement
738 if ((bp->b_flags & B_INVAL) || (bp->b_flags & B_DELWRI) == 0)
739 atomic_subtract_int(&numfreebuffers, 1);
744 * Get a buffer with the specified data. Look in the cache first. We
745 * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE
746 * is set, the buffer is valid and we do not have to do anything ( see
747 * getblk() ). This is really just a special case of breadn().
750 bread(struct vnode * vp, daddr_t blkno, int size, struct ucred * cred,
754 return (breadn(vp, blkno, size, 0, 0, 0, cred, bpp));
758 * Attempt to initiate asynchronous I/O on read-ahead blocks. We must
759 * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set,
760 * the buffer is valid and we do not have to do anything.
763 breada(struct vnode * vp, daddr_t * rablkno, int * rabsize,
764 int cnt, struct ucred * cred)
769 for (i = 0; i < cnt; i++, rablkno++, rabsize++) {
770 if (inmem(vp, *rablkno))
772 rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0);
774 if ((rabp->b_flags & B_CACHE) == 0) {
775 if (!TD_IS_IDLETHREAD(curthread))
776 curthread->td_ru.ru_inblock++;
777 rabp->b_flags |= B_ASYNC;
778 rabp->b_flags &= ~B_INVAL;
779 rabp->b_ioflags &= ~BIO_ERROR;
780 rabp->b_iocmd = BIO_READ;
781 if (rabp->b_rcred == NOCRED && cred != NOCRED)
782 rabp->b_rcred = crhold(cred);
783 vfs_busy_pages(rabp, 0);
785 rabp->b_iooffset = dbtob(rabp->b_blkno);
794 * Operates like bread, but also starts asynchronous I/O on
798 breadn(struct vnode * vp, daddr_t blkno, int size,
799 daddr_t * rablkno, int *rabsize,
800 int cnt, struct ucred * cred, struct buf **bpp)
803 int rv = 0, readwait = 0;
805 CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size);
806 *bpp = bp = getblk(vp, blkno, size, 0, 0, 0);
808 /* if not found in cache, do some I/O */
809 if ((bp->b_flags & B_CACHE) == 0) {
810 if (!TD_IS_IDLETHREAD(curthread))
811 curthread->td_ru.ru_inblock++;
812 bp->b_iocmd = BIO_READ;
813 bp->b_flags &= ~B_INVAL;
814 bp->b_ioflags &= ~BIO_ERROR;
815 if (bp->b_rcred == NOCRED && cred != NOCRED)
816 bp->b_rcred = crhold(cred);
817 vfs_busy_pages(bp, 0);
818 bp->b_iooffset = dbtob(bp->b_blkno);
823 breada(vp, rablkno, rabsize, cnt, cred);
832 * Write, release buffer on completion. (Done by iodone
833 * if async). Do not bother writing anything if the buffer
836 * Note that we set B_CACHE here, indicating that buffer is
837 * fully valid and thus cacheable. This is true even of NFS
838 * now so we set it generally. This could be set either here
839 * or in biodone() since the I/O is synchronous. We put it
843 bufwrite(struct buf *bp)
849 CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
850 if (bp->b_flags & B_INVAL) {
855 oldflags = bp->b_flags;
859 if (bp->b_pin_count > 0)
862 KASSERT(!(bp->b_vflags & BV_BKGRDINPROG),
863 ("FFS background buffer should not get here %p", bp));
867 vp_md = vp->v_vflag & VV_MD;
871 /* Mark the buffer clean */
874 bp->b_flags &= ~B_DONE;
875 bp->b_ioflags &= ~BIO_ERROR;
876 bp->b_flags |= B_CACHE;
877 bp->b_iocmd = BIO_WRITE;
879 bufobj_wref(bp->b_bufobj);
880 vfs_busy_pages(bp, 1);
883 * Normal bwrites pipeline writes
885 bp->b_runningbufspace = bp->b_bufsize;
886 atomic_add_long(&runningbufspace, bp->b_runningbufspace);
888 if (!TD_IS_IDLETHREAD(curthread))
889 curthread->td_ru.ru_oublock++;
890 if (oldflags & B_ASYNC)
892 bp->b_iooffset = dbtob(bp->b_blkno);
895 if ((oldflags & B_ASYNC) == 0) {
896 int rtval = bufwait(bp);
901 * don't allow the async write to saturate the I/O
902 * system. We will not deadlock here because
903 * we are blocking waiting for I/O that is already in-progress
904 * to complete. We do not block here if it is the update
905 * or syncer daemon trying to clean up as that can lead
908 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md)
909 waitrunningbufspace();
916 bufbdflush(struct bufobj *bo, struct buf *bp)
920 if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10) {
921 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread);
923 } else if (bo->bo_dirty.bv_cnt > dirtybufthresh) {
926 * Try to find a buffer to flush.
928 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) {
929 if ((nbp->b_vflags & BV_BKGRDINPROG) ||
931 LK_EXCLUSIVE | LK_NOWAIT, NULL))
934 panic("bdwrite: found ourselves");
936 /* Don't countdeps with the bo lock held. */
937 if (buf_countdeps(nbp, 0)) {
942 if (nbp->b_flags & B_CLUSTEROK) {
948 dirtybufferflushes++;
957 * Delayed write. (Buffer is marked dirty). Do not bother writing
958 * anything if the buffer is marked invalid.
960 * Note that since the buffer must be completely valid, we can safely
961 * set B_CACHE. In fact, we have to set B_CACHE here rather then in
962 * biodone() in order to prevent getblk from writing the buffer
966 bdwrite(struct buf *bp)
968 struct thread *td = curthread;
972 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
973 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
976 if (bp->b_flags & B_INVAL) {
982 * If we have too many dirty buffers, don't create any more.
983 * If we are wildly over our limit, then force a complete
984 * cleanup. Otherwise, just keep the situation from getting
985 * out of control. Note that we have to avoid a recursive
986 * disaster and not try to clean up after our own cleanup!
990 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) {
991 td->td_pflags |= TDP_INBDFLUSH;
993 td->td_pflags &= ~TDP_INBDFLUSH;
999 * Set B_CACHE, indicating that the buffer is fully valid. This is
1000 * true even of NFS now.
1002 bp->b_flags |= B_CACHE;
1005 * This bmap keeps the system from needing to do the bmap later,
1006 * perhaps when the system is attempting to do a sync. Since it
1007 * is likely that the indirect block -- or whatever other datastructure
1008 * that the filesystem needs is still in memory now, it is a good
1009 * thing to do this. Note also, that if the pageout daemon is
1010 * requesting a sync -- there might not be enough memory to do
1011 * the bmap then... So, this is important to do.
1013 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) {
1014 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL);
1018 * Set the *dirty* buffer range based upon the VM system dirty pages.
1023 * We need to do this here to satisfy the vnode_pager and the
1024 * pageout daemon, so that it thinks that the pages have been
1025 * "cleaned". Note that since the pages are in a delayed write
1026 * buffer -- the VFS layer "will" see that the pages get written
1027 * out on the next sync, or perhaps the cluster will be completed.
1029 vfs_clean_pages(bp);
1033 * Wakeup the buffer flushing daemon if we have a lot of dirty
1034 * buffers (midpoint between our recovery point and our stall
1037 bd_wakeup((lodirtybuffers + hidirtybuffers) / 2);
1040 * note: we cannot initiate I/O from a bdwrite even if we wanted to,
1041 * due to the softdep code.
1048 * Turn buffer into delayed write request. We must clear BIO_READ and
1049 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to
1050 * itself to properly update it in the dirty/clean lists. We mark it
1051 * B_DONE to ensure that any asynchronization of the buffer properly
1052 * clears B_DONE ( else a panic will occur later ).
1054 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which
1055 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty()
1056 * should only be called if the buffer is known-good.
1058 * Since the buffer is not on a queue, we do not update the numfreebuffers
1061 * The buffer must be on QUEUE_NONE.
1064 bdirty(struct buf *bp)
1067 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X",
1068 bp, bp->b_vp, bp->b_flags);
1069 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
1070 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE,
1071 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex));
1072 BUF_ASSERT_HELD(bp);
1073 bp->b_flags &= ~(B_RELBUF);
1074 bp->b_iocmd = BIO_WRITE;
1076 if ((bp->b_flags & B_DELWRI) == 0) {
1077 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI;
1079 atomic_add_int(&numdirtybuffers, 1);
1080 bd_wakeup((lodirtybuffers + hidirtybuffers) / 2);
1087 * Clear B_DELWRI for buffer.
1089 * Since the buffer is not on a queue, we do not update the numfreebuffers
1092 * The buffer must be on QUEUE_NONE.
1096 bundirty(struct buf *bp)
1099 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
1100 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
1101 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE,
1102 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex));
1103 BUF_ASSERT_HELD(bp);
1105 if (bp->b_flags & B_DELWRI) {
1106 bp->b_flags &= ~B_DELWRI;
1108 atomic_subtract_int(&numdirtybuffers, 1);
1109 numdirtywakeup(lodirtybuffers);
1112 * Since it is now being written, we can clear its deferred write flag.
1114 bp->b_flags &= ~B_DEFERRED;
1120 * Asynchronous write. Start output on a buffer, but do not wait for
1121 * it to complete. The buffer is released when the output completes.
1123 * bwrite() ( or the VOP routine anyway ) is responsible for handling
1124 * B_INVAL buffers. Not us.
1127 bawrite(struct buf *bp)
1130 bp->b_flags |= B_ASYNC;
1137 * Called prior to the locking of any vnodes when we are expecting to
1138 * write. We do not want to starve the buffer cache with too many
1139 * dirty buffers so we block here. By blocking prior to the locking
1140 * of any vnodes we attempt to avoid the situation where a locked vnode
1141 * prevents the various system daemons from flushing related buffers.
1148 if (numdirtybuffers >= hidirtybuffers) {
1150 while (numdirtybuffers >= hidirtybuffers) {
1152 needsbuffer |= VFS_BIO_NEED_DIRTYFLUSH;
1153 msleep(&needsbuffer, &nblock,
1154 (PRIBIO + 4), "flswai", 0);
1156 mtx_unlock(&nblock);
1161 * Return true if we have too many dirty buffers.
1164 buf_dirty_count_severe(void)
1167 return(numdirtybuffers >= hidirtybuffers);
1173 * Release a busy buffer and, if requested, free its resources. The
1174 * buffer will be stashed in the appropriate bufqueue[] allowing it
1175 * to be accessed later as a cache entity or reused for other purposes.
1178 brelse(struct buf *bp)
1180 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X",
1181 bp, bp->b_vp, bp->b_flags);
1182 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)),
1183 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp));
1185 if (bp->b_flags & B_MANAGED) {
1190 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) &&
1191 bp->b_error == EIO && !(bp->b_flags & B_INVAL)) {
1193 * Failed write, redirty. Must clear BIO_ERROR to prevent
1194 * pages from being scrapped. If the error is anything
1195 * other than an I/O error (EIO), assume that retryingi
1198 bp->b_ioflags &= ~BIO_ERROR;
1200 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) ||
1201 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) {
1203 * Either a failed I/O or we were asked to free or not
1206 bp->b_flags |= B_INVAL;
1207 if (!LIST_EMPTY(&bp->b_dep))
1209 if (bp->b_flags & B_DELWRI) {
1210 atomic_subtract_int(&numdirtybuffers, 1);
1211 numdirtywakeup(lodirtybuffers);
1213 bp->b_flags &= ~(B_DELWRI | B_CACHE);
1214 if ((bp->b_flags & B_VMIO) == 0) {
1223 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_release()
1224 * is called with B_DELWRI set, the underlying pages may wind up
1225 * getting freed causing a previous write (bdwrite()) to get 'lost'
1226 * because pages associated with a B_DELWRI bp are marked clean.
1228 * We still allow the B_INVAL case to call vfs_vmio_release(), even
1229 * if B_DELWRI is set.
1231 * If B_DELWRI is not set we may have to set B_RELBUF if we are low
1232 * on pages to return pages to the VM page queues.
1234 if (bp->b_flags & B_DELWRI)
1235 bp->b_flags &= ~B_RELBUF;
1236 else if (vm_page_count_severe()) {
1238 * The locking of the BO_LOCK is not necessary since
1239 * BKGRDINPROG cannot be set while we hold the buf
1240 * lock, it can only be cleared if it is already
1244 if (!(bp->b_vflags & BV_BKGRDINPROG))
1245 bp->b_flags |= B_RELBUF;
1247 bp->b_flags |= B_RELBUF;
1251 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer
1252 * constituted, not even NFS buffers now. Two flags effect this. If
1253 * B_INVAL, the struct buf is invalidated but the VM object is kept
1254 * around ( i.e. so it is trivial to reconstitute the buffer later ).
1256 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be
1257 * invalidated. BIO_ERROR cannot be set for a failed write unless the
1258 * buffer is also B_INVAL because it hits the re-dirtying code above.
1260 * Normally we can do this whether a buffer is B_DELWRI or not. If
1261 * the buffer is an NFS buffer, it is tracking piecemeal writes or
1262 * the commit state and we cannot afford to lose the buffer. If the
1263 * buffer has a background write in progress, we need to keep it
1264 * around to prevent it from being reconstituted and starting a second
1267 if ((bp->b_flags & B_VMIO)
1268 && !(bp->b_vp->v_mount != NULL &&
1269 (bp->b_vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 &&
1270 !vn_isdisk(bp->b_vp, NULL) &&
1271 (bp->b_flags & B_DELWRI))
1280 obj = bp->b_bufobj->bo_object;
1283 * Get the base offset and length of the buffer. Note that
1284 * in the VMIO case if the buffer block size is not
1285 * page-aligned then b_data pointer may not be page-aligned.
1286 * But our b_pages[] array *IS* page aligned.
1288 * block sizes less then DEV_BSIZE (usually 512) are not
1289 * supported due to the page granularity bits (m->valid,
1290 * m->dirty, etc...).
1292 * See man buf(9) for more information
1294 resid = bp->b_bufsize;
1295 foff = bp->b_offset;
1296 VM_OBJECT_LOCK(obj);
1297 for (i = 0; i < bp->b_npages; i++) {
1303 * If we hit a bogus page, fixup *all* the bogus pages
1306 if (m == bogus_page) {
1307 poff = OFF_TO_IDX(bp->b_offset);
1310 for (j = i; j < bp->b_npages; j++) {
1312 mtmp = bp->b_pages[j];
1313 if (mtmp == bogus_page) {
1314 mtmp = vm_page_lookup(obj, poff + j);
1316 panic("brelse: page missing\n");
1318 bp->b_pages[j] = mtmp;
1322 if ((bp->b_flags & B_INVAL) == 0) {
1324 trunc_page((vm_offset_t)bp->b_data),
1325 bp->b_pages, bp->b_npages);
1329 if ((bp->b_flags & B_NOCACHE) ||
1330 (bp->b_ioflags & BIO_ERROR)) {
1331 int poffset = foff & PAGE_MASK;
1332 int presid = resid > (PAGE_SIZE - poffset) ?
1333 (PAGE_SIZE - poffset) : resid;
1335 KASSERT(presid >= 0, ("brelse: extra page"));
1336 vm_page_lock_queues();
1337 vm_page_set_invalid(m, poffset, presid);
1338 vm_page_unlock_queues();
1340 printf("avoided corruption bug in bogus_page/brelse code\n");
1342 resid -= PAGE_SIZE - (foff & PAGE_MASK);
1343 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
1345 VM_OBJECT_UNLOCK(obj);
1346 if (bp->b_flags & (B_INVAL | B_RELBUF))
1347 vfs_vmio_release(bp);
1349 } else if (bp->b_flags & B_VMIO) {
1351 if (bp->b_flags & (B_INVAL | B_RELBUF)) {
1352 vfs_vmio_release(bp);
1355 } else if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0) {
1356 if (bp->b_bufsize != 0)
1358 if (bp->b_vp != NULL)
1362 if (BUF_LOCKRECURSED(bp)) {
1363 /* do not release to free list */
1370 /* Handle delayed bremfree() processing. */
1371 if (bp->b_flags & B_REMFREE)
1373 if (bp->b_qindex != QUEUE_NONE)
1374 panic("brelse: free buffer onto another queue???");
1377 * If the buffer has junk contents signal it and eventually
1378 * clean up B_DELWRI and diassociate the vnode so that gbincore()
1381 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 ||
1382 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0)
1383 bp->b_flags |= B_INVAL;
1384 if (bp->b_flags & B_INVAL) {
1385 if (bp->b_flags & B_DELWRI)
1391 /* buffers with no memory */
1392 if (bp->b_bufsize == 0) {
1393 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA);
1394 if (bp->b_vflags & BV_BKGRDINPROG)
1395 panic("losing buffer 1");
1396 if (bp->b_kvasize) {
1397 bp->b_qindex = QUEUE_EMPTYKVA;
1399 bp->b_qindex = QUEUE_EMPTY;
1401 TAILQ_INSERT_HEAD(&bufqueues[bp->b_qindex], bp, b_freelist);
1402 /* buffers with junk contents */
1403 } else if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) ||
1404 (bp->b_ioflags & BIO_ERROR)) {
1405 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA);
1406 if (bp->b_vflags & BV_BKGRDINPROG)
1407 panic("losing buffer 2");
1408 bp->b_qindex = QUEUE_CLEAN;
1409 TAILQ_INSERT_HEAD(&bufqueues[QUEUE_CLEAN], bp, b_freelist);
1410 /* remaining buffers */
1412 if ((bp->b_flags & (B_DELWRI|B_NEEDSGIANT)) ==
1413 (B_DELWRI|B_NEEDSGIANT))
1414 bp->b_qindex = QUEUE_DIRTY_GIANT;
1415 else if (bp->b_flags & B_DELWRI)
1416 bp->b_qindex = QUEUE_DIRTY;
1418 bp->b_qindex = QUEUE_CLEAN;
1419 if (bp->b_flags & B_AGE)
1420 TAILQ_INSERT_HEAD(&bufqueues[bp->b_qindex], bp, b_freelist);
1422 TAILQ_INSERT_TAIL(&bufqueues[bp->b_qindex], bp, b_freelist);
1424 mtx_unlock(&bqlock);
1427 * Fixup numfreebuffers count. The bp is on an appropriate queue
1428 * unless locked. We then bump numfreebuffers if it is not B_DELWRI.
1429 * We've already handled the B_INVAL case ( B_DELWRI will be clear
1430 * if B_INVAL is set ).
1433 if (!(bp->b_flags & B_DELWRI))
1437 * Something we can maybe free or reuse
1439 if (bp->b_bufsize || bp->b_kvasize)
1442 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF | B_DIRECT);
1443 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY))
1444 panic("brelse: not dirty");
1450 * Release a buffer back to the appropriate queue but do not try to free
1451 * it. The buffer is expected to be used again soon.
1453 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by
1454 * biodone() to requeue an async I/O on completion. It is also used when
1455 * known good buffers need to be requeued but we think we may need the data
1458 * XXX we should be able to leave the B_RELBUF hint set on completion.
1461 bqrelse(struct buf *bp)
1463 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
1464 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)),
1465 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp));
1467 if (BUF_LOCKRECURSED(bp)) {
1468 /* do not release to free list */
1473 if (bp->b_flags & B_MANAGED) {
1474 if (bp->b_flags & B_REMFREE) {
1477 mtx_unlock(&bqlock);
1479 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF);
1485 /* Handle delayed bremfree() processing. */
1486 if (bp->b_flags & B_REMFREE)
1488 if (bp->b_qindex != QUEUE_NONE)
1489 panic("bqrelse: free buffer onto another queue???");
1490 /* buffers with stale but valid contents */
1491 if (bp->b_flags & B_DELWRI) {
1492 if (bp->b_flags & B_NEEDSGIANT)
1493 bp->b_qindex = QUEUE_DIRTY_GIANT;
1495 bp->b_qindex = QUEUE_DIRTY;
1496 TAILQ_INSERT_TAIL(&bufqueues[bp->b_qindex], bp, b_freelist);
1499 * The locking of the BO_LOCK for checking of the
1500 * BV_BKGRDINPROG is not necessary since the
1501 * BV_BKGRDINPROG cannot be set while we hold the buf
1502 * lock, it can only be cleared if it is already
1505 if (!vm_page_count_severe() || (bp->b_vflags & BV_BKGRDINPROG)) {
1506 bp->b_qindex = QUEUE_CLEAN;
1507 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_CLEAN], bp,
1511 * We are too low on memory, we have to try to free
1512 * the buffer (most importantly: the wired pages
1513 * making up its backing store) *now*.
1515 mtx_unlock(&bqlock);
1520 mtx_unlock(&bqlock);
1522 if ((bp->b_flags & B_INVAL) || !(bp->b_flags & B_DELWRI))
1526 * Something we can maybe free or reuse.
1528 if (bp->b_bufsize && !(bp->b_flags & B_DELWRI))
1531 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF);
1532 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY))
1533 panic("bqrelse: not dirty");
1538 /* Give pages used by the bp back to the VM system (where possible) */
1540 vfs_vmio_release(struct buf *bp)
1545 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
1546 vm_page_lock_queues();
1547 for (i = 0; i < bp->b_npages; i++) {
1549 bp->b_pages[i] = NULL;
1551 * In order to keep page LRU ordering consistent, put
1552 * everything on the inactive queue.
1554 vm_page_unwire(m, 0);
1556 * We don't mess with busy pages, it is
1557 * the responsibility of the process that
1558 * busied the pages to deal with them.
1560 if ((m->oflags & VPO_BUSY) || (m->busy != 0))
1563 if (m->wire_count == 0) {
1565 * Might as well free the page if we can and it has
1566 * no valid data. We also free the page if the
1567 * buffer was used for direct I/O
1569 if ((bp->b_flags & B_ASYNC) == 0 && !m->valid &&
1570 m->hold_count == 0) {
1572 } else if (bp->b_flags & B_DIRECT) {
1573 vm_page_try_to_free(m);
1574 } else if (vm_page_count_severe()) {
1575 vm_page_try_to_cache(m);
1579 vm_page_unlock_queues();
1580 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
1581 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages);
1583 if (bp->b_bufsize) {
1588 bp->b_flags &= ~B_VMIO;
1594 * Check to see if a block at a particular lbn is available for a clustered
1598 vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno)
1605 /* If the buf isn't in core skip it */
1606 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL)
1609 /* If the buf is busy we don't want to wait for it */
1610 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0)
1613 /* Only cluster with valid clusterable delayed write buffers */
1614 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) !=
1615 (B_DELWRI | B_CLUSTEROK))
1618 if (bpa->b_bufsize != size)
1622 * Check to see if it is in the expected place on disk and that the
1623 * block has been mapped.
1625 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno))
1635 * Implement clustered async writes for clearing out B_DELWRI buffers.
1636 * This is much better then the old way of writing only one buffer at
1637 * a time. Note that we may not be presented with the buffers in the
1638 * correct order, so we search for the cluster in both directions.
1641 vfs_bio_awrite(struct buf *bp)
1646 daddr_t lblkno = bp->b_lblkno;
1647 struct vnode *vp = bp->b_vp;
1655 * right now we support clustered writing only to regular files. If
1656 * we find a clusterable block we could be in the middle of a cluster
1657 * rather then at the beginning.
1659 if ((vp->v_type == VREG) &&
1660 (vp->v_mount != 0) && /* Only on nodes that have the size info */
1661 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) {
1663 size = vp->v_mount->mnt_stat.f_iosize;
1664 maxcl = MAXPHYS / size;
1667 for (i = 1; i < maxcl; i++)
1668 if (vfs_bio_clcheck(vp, size, lblkno + i,
1669 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0)
1672 for (j = 1; i + j <= maxcl && j <= lblkno; j++)
1673 if (vfs_bio_clcheck(vp, size, lblkno - j,
1674 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0)
1680 * this is a possible cluster write
1684 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl);
1689 bp->b_flags |= B_ASYNC;
1691 * default (old) behavior, writing out only one block
1693 * XXX returns b_bufsize instead of b_bcount for nwritten?
1695 nwritten = bp->b_bufsize;
1704 * Find and initialize a new buffer header, freeing up existing buffers
1705 * in the bufqueues as necessary. The new buffer is returned locked.
1707 * Important: B_INVAL is not set. If the caller wishes to throw the
1708 * buffer away, the caller must set B_INVAL prior to calling brelse().
1711 * We have insufficient buffer headers
1712 * We have insufficient buffer space
1713 * buffer_map is too fragmented ( space reservation fails )
1714 * If we have to flush dirty buffers ( but we try to avoid this )
1716 * To avoid VFS layer recursion we do not flush dirty buffers ourselves.
1717 * Instead we ask the buf daemon to do it for us. We attempt to
1718 * avoid piecemeal wakeups of the pageout daemon.
1722 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int size, int maxsize,
1730 static int flushingbufs;
1734 * We can't afford to block since we might be holding a vnode lock,
1735 * which may prevent system daemons from running. We deal with
1736 * low-memory situations by proactively returning memory and running
1737 * async I/O rather then sync I/O.
1739 atomic_add_int(&getnewbufcalls, 1);
1740 atomic_subtract_int(&getnewbufrestarts, 1);
1742 atomic_add_int(&getnewbufrestarts, 1);
1745 * Setup for scan. If we do not have enough free buffers,
1746 * we setup a degenerate case that immediately fails. Note
1747 * that if we are specially marked process, we are allowed to
1748 * dip into our reserves.
1750 * The scanning sequence is nominally: EMPTY->EMPTYKVA->CLEAN
1752 * We start with EMPTYKVA. If the list is empty we backup to EMPTY.
1753 * However, there are a number of cases (defragging, reusing, ...)
1754 * where we cannot backup.
1757 nqindex = QUEUE_EMPTYKVA;
1758 nbp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTYKVA]);
1762 * If no EMPTYKVA buffers and we are either
1763 * defragging or reusing, locate a CLEAN buffer
1764 * to free or reuse. If bufspace useage is low
1765 * skip this step so we can allocate a new buffer.
1767 if (defrag || bufspace >= lobufspace) {
1768 nqindex = QUEUE_CLEAN;
1769 nbp = TAILQ_FIRST(&bufqueues[QUEUE_CLEAN]);
1773 * If we could not find or were not allowed to reuse a
1774 * CLEAN buffer, check to see if it is ok to use an EMPTY
1775 * buffer. We can only use an EMPTY buffer if allocating
1776 * its KVA would not otherwise run us out of buffer space.
1778 if (nbp == NULL && defrag == 0 &&
1779 bufspace + maxsize < hibufspace) {
1780 nqindex = QUEUE_EMPTY;
1781 nbp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]);
1786 * Run scan, possibly freeing data and/or kva mappings on the fly
1790 while ((bp = nbp) != NULL) {
1791 int qindex = nqindex;
1794 * Calculate next bp ( we can only use it if we do not block
1795 * or do other fancy things ).
1797 if ((nbp = TAILQ_NEXT(bp, b_freelist)) == NULL) {
1800 nqindex = QUEUE_EMPTYKVA;
1801 if ((nbp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTYKVA])))
1804 case QUEUE_EMPTYKVA:
1805 nqindex = QUEUE_CLEAN;
1806 if ((nbp = TAILQ_FIRST(&bufqueues[QUEUE_CLEAN])))
1817 * If we are defragging then we need a buffer with
1818 * b_kvasize != 0. XXX this situation should no longer
1819 * occur, if defrag is non-zero the buffer's b_kvasize
1820 * should also be non-zero at this point. XXX
1822 if (defrag && bp->b_kvasize == 0) {
1823 printf("Warning: defrag empty buffer %p\n", bp);
1828 * Start freeing the bp. This is somewhat involved. nbp
1829 * remains valid only for QUEUE_EMPTY[KVA] bp's.
1831 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0)
1834 BO_LOCK(bp->b_bufobj);
1835 if (bp->b_vflags & BV_BKGRDINPROG) {
1836 BO_UNLOCK(bp->b_bufobj);
1840 BO_UNLOCK(bp->b_bufobj);
1843 "getnewbuf(%p) vp %p flags %X kvasize %d bufsize %d "
1844 "queue %d (recycling)", bp, bp->b_vp, bp->b_flags,
1845 bp->b_kvasize, bp->b_bufsize, qindex);
1850 KASSERT(bp->b_qindex == qindex, ("getnewbuf: inconsistant queue %d bp %p", qindex, bp));
1853 * Note: we no longer distinguish between VMIO and non-VMIO
1857 KASSERT((bp->b_flags & B_DELWRI) == 0, ("delwri buffer %p found in queue %d", bp, qindex));
1860 mtx_unlock(&bqlock);
1862 if (qindex == QUEUE_CLEAN) {
1863 if (bp->b_flags & B_VMIO) {
1864 bp->b_flags &= ~B_ASYNC;
1865 vfs_vmio_release(bp);
1872 * NOTE: nbp is now entirely invalid. We can only restart
1873 * the scan from this point on.
1875 * Get the rest of the buffer freed up. b_kva* is still
1876 * valid after this operation.
1879 if (bp->b_rcred != NOCRED) {
1880 crfree(bp->b_rcred);
1881 bp->b_rcred = NOCRED;
1883 if (bp->b_wcred != NOCRED) {
1884 crfree(bp->b_wcred);
1885 bp->b_wcred = NOCRED;
1887 if (!LIST_EMPTY(&bp->b_dep))
1889 if (bp->b_vflags & BV_BKGRDINPROG)
1890 panic("losing buffer 3");
1891 KASSERT(bp->b_vp == NULL,
1892 ("bp: %p still has vnode %p. qindex: %d",
1893 bp, bp->b_vp, qindex));
1894 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0,
1895 ("bp: %p still on a buffer list. xflags %X",
1906 bp->b_blkno = bp->b_lblkno = 0;
1907 bp->b_offset = NOOFFSET;
1913 bp->b_dirtyoff = bp->b_dirtyend = 0;
1914 bp->b_bufobj = NULL;
1915 bp->b_pin_count = 0;
1916 bp->b_fsprivate1 = NULL;
1917 bp->b_fsprivate2 = NULL;
1918 bp->b_fsprivate3 = NULL;
1920 LIST_INIT(&bp->b_dep);
1923 * If we are defragging then free the buffer.
1926 bp->b_flags |= B_INVAL;
1934 * Notify any waiters for the buffer lock about
1935 * identity change by freeing the buffer.
1937 if (qindex == QUEUE_CLEAN && BUF_LOCKWAITERS(bp)) {
1938 bp->b_flags |= B_INVAL;
1945 * If we are overcomitted then recover the buffer and its
1946 * KVM space. This occurs in rare situations when multiple
1947 * processes are blocked in getnewbuf() or allocbuf().
1949 if (bufspace >= hibufspace)
1951 if (flushingbufs && bp->b_kvasize != 0) {
1952 bp->b_flags |= B_INVAL;
1957 if (bufspace < lobufspace)
1963 * If we exhausted our list, sleep as appropriate. We may have to
1964 * wakeup various daemons and write out some dirty buffers.
1966 * Generally we are sleeping due to insufficient buffer space.
1970 int flags, norunbuf;
1975 flags = VFS_BIO_NEED_BUFSPACE;
1977 } else if (bufspace >= hibufspace) {
1979 flags = VFS_BIO_NEED_BUFSPACE;
1982 flags = VFS_BIO_NEED_ANY;
1985 needsbuffer |= flags;
1986 mtx_unlock(&nblock);
1987 mtx_unlock(&bqlock);
1989 bd_speedup(); /* heeeelp */
1990 if (gbflags & GB_NOWAIT_BD)
1994 while (needsbuffer & flags) {
1995 if (vp != NULL && (td->td_pflags & TDP_BUFNEED) == 0) {
1996 mtx_unlock(&nblock);
1998 * getblk() is called with a vnode
1999 * locked, and some majority of the
2000 * dirty buffers may as well belong to
2001 * the vnode. Flushing the buffers
2002 * there would make a progress that
2003 * cannot be achieved by the
2004 * buf_daemon, that cannot lock the
2007 norunbuf = ~(TDP_BUFNEED | TDP_NORUNNINGBUF) |
2008 (td->td_pflags & TDP_NORUNNINGBUF);
2009 /* play bufdaemon */
2010 td->td_pflags |= TDP_BUFNEED | TDP_NORUNNINGBUF;
2011 fl = buf_do_flush(vp);
2012 td->td_pflags &= norunbuf;
2016 if ((needsbuffer & flags) == 0)
2019 if (msleep(&needsbuffer, &nblock,
2020 (PRIBIO + 4) | slpflag, waitmsg, slptimeo)) {
2021 mtx_unlock(&nblock);
2025 mtx_unlock(&nblock);
2028 * We finally have a valid bp. We aren't quite out of the
2029 * woods, we still have to reserve kva space. In order
2030 * to keep fragmentation sane we only allocate kva in
2033 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK;
2035 if (maxsize != bp->b_kvasize) {
2036 vm_offset_t addr = 0;
2040 vm_map_lock(buffer_map);
2041 if (vm_map_findspace(buffer_map,
2042 vm_map_min(buffer_map), maxsize, &addr)) {
2044 * Uh oh. Buffer map is to fragmented. We
2045 * must defragment the map.
2047 atomic_add_int(&bufdefragcnt, 1);
2048 vm_map_unlock(buffer_map);
2050 bp->b_flags |= B_INVAL;
2055 vm_map_insert(buffer_map, NULL, 0,
2056 addr, addr + maxsize,
2057 VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
2059 bp->b_kvabase = (caddr_t) addr;
2060 bp->b_kvasize = maxsize;
2061 atomic_add_long(&bufspace, bp->b_kvasize);
2062 atomic_add_int(&bufreusecnt, 1);
2064 vm_map_unlock(buffer_map);
2066 bp->b_saveaddr = bp->b_kvabase;
2067 bp->b_data = bp->b_saveaddr;
2075 * buffer flushing daemon. Buffers are normally flushed by the
2076 * update daemon but if it cannot keep up this process starts to
2077 * take the load in an attempt to prevent getnewbuf() from blocking.
2080 static struct kproc_desc buf_kp = {
2085 SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp);
2088 buf_do_flush(struct vnode *vp)
2092 flushed = flushbufqueues(vp, QUEUE_DIRTY, 0);
2093 /* The list empty check here is slightly racy */
2094 if (!TAILQ_EMPTY(&bufqueues[QUEUE_DIRTY_GIANT])) {
2096 flushed += flushbufqueues(vp, QUEUE_DIRTY_GIANT, 0);
2101 * Could not find any buffers without rollback
2102 * dependencies, so just write the first one
2103 * in the hopes of eventually making progress.
2105 flushbufqueues(vp, QUEUE_DIRTY, 1);
2107 &bufqueues[QUEUE_DIRTY_GIANT])) {
2109 flushbufqueues(vp, QUEUE_DIRTY_GIANT, 1);
2121 * This process needs to be suspended prior to shutdown sync.
2123 EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, bufdaemonproc,
2127 * This process is allowed to take the buffer cache to the limit
2129 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED;
2133 mtx_unlock(&bdlock);
2135 kproc_suspend_check(bufdaemonproc);
2138 * Do the flush. Limit the amount of in-transit I/O we
2139 * allow to build up, otherwise we would completely saturate
2140 * the I/O system. Wakeup any waiting processes before we
2141 * normally would so they can run in parallel with our drain.
2143 while (numdirtybuffers > lodirtybuffers) {
2144 if (buf_do_flush(NULL) == 0)
2150 * Only clear bd_request if we have reached our low water
2151 * mark. The buf_daemon normally waits 1 second and
2152 * then incrementally flushes any dirty buffers that have
2153 * built up, within reason.
2155 * If we were unable to hit our low water mark and couldn't
2156 * find any flushable buffers, we sleep half a second.
2157 * Otherwise we loop immediately.
2160 if (numdirtybuffers <= lodirtybuffers) {
2162 * We reached our low water mark, reset the
2163 * request and sleep until we are needed again.
2164 * The sleep is just so the suspend code works.
2167 msleep(&bd_request, &bdlock, PVM, "psleep", hz);
2170 * We couldn't find any flushable dirty buffers but
2171 * still have too many dirty buffers, we
2172 * have to sleep and try again. (rare)
2174 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10);
2182 * Try to flush a buffer in the dirty queue. We must be careful to
2183 * free up B_INVAL buffers instead of write them, which NFS is
2184 * particularly sensitive to.
2186 static int flushwithdeps = 0;
2187 SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW, &flushwithdeps,
2188 0, "Number of buffers flushed with dependecies that require rollbacks");
2191 flushbufqueues(struct vnode *lvp, int queue, int flushdeps)
2193 struct buf *sentinel;
2202 target = numdirtybuffers - lodirtybuffers;
2203 if (flushdeps && target > 2)
2206 target = flushbufqtarget;
2209 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO);
2210 sentinel->b_qindex = QUEUE_SENTINEL;
2212 TAILQ_INSERT_HEAD(&bufqueues[queue], sentinel, b_freelist);
2213 while (flushed != target) {
2214 bp = TAILQ_NEXT(sentinel, b_freelist);
2216 TAILQ_REMOVE(&bufqueues[queue], sentinel, b_freelist);
2217 TAILQ_INSERT_AFTER(&bufqueues[queue], bp, sentinel,
2222 * Skip sentinels inserted by other invocations of the
2223 * flushbufqueues(), taking care to not reorder them.
2225 if (bp->b_qindex == QUEUE_SENTINEL)
2228 * Only flush the buffers that belong to the
2229 * vnode locked by the curthread.
2231 if (lvp != NULL && bp->b_vp != lvp)
2233 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0)
2235 if (bp->b_pin_count > 0) {
2239 BO_LOCK(bp->b_bufobj);
2240 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 ||
2241 (bp->b_flags & B_DELWRI) == 0) {
2242 BO_UNLOCK(bp->b_bufobj);
2246 BO_UNLOCK(bp->b_bufobj);
2247 if (bp->b_flags & B_INVAL) {
2249 mtx_unlock(&bqlock);
2252 numdirtywakeup((lodirtybuffers + hidirtybuffers) / 2);
2257 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) {
2258 if (flushdeps == 0) {
2266 * We must hold the lock on a vnode before writing
2267 * one of its buffers. Otherwise we may confuse, or
2268 * in the case of a snapshot vnode, deadlock the
2271 * The lock order here is the reverse of the normal
2272 * of vnode followed by buf lock. This is ok because
2273 * the NOWAIT will prevent deadlock.
2276 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
2280 if (vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_CANRECURSE) == 0) {
2281 mtx_unlock(&bqlock);
2282 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X",
2283 bp, bp->b_vp, bp->b_flags);
2284 if (curproc == bufdaemonproc)
2291 vn_finished_write(mp);
2293 flushwithdeps += hasdeps;
2297 * Sleeping on runningbufspace while holding
2298 * vnode lock leads to deadlock.
2300 if (curproc == bufdaemonproc)
2301 waitrunningbufspace();
2302 numdirtywakeup((lodirtybuffers + hidirtybuffers) / 2);
2306 vn_finished_write(mp);
2309 TAILQ_REMOVE(&bufqueues[queue], sentinel, b_freelist);
2310 mtx_unlock(&bqlock);
2311 free(sentinel, M_TEMP);
2316 * Check to see if a block is currently memory resident.
2319 incore(struct bufobj *bo, daddr_t blkno)
2324 bp = gbincore(bo, blkno);
2330 * Returns true if no I/O is needed to access the
2331 * associated VM object. This is like incore except
2332 * it also hunts around in the VM system for the data.
2336 inmem(struct vnode * vp, daddr_t blkno)
2339 vm_offset_t toff, tinc, size;
2343 ASSERT_VOP_LOCKED(vp, "inmem");
2345 if (incore(&vp->v_bufobj, blkno))
2347 if (vp->v_mount == NULL)
2354 if (size > vp->v_mount->mnt_stat.f_iosize)
2355 size = vp->v_mount->mnt_stat.f_iosize;
2356 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize;
2358 VM_OBJECT_LOCK(obj);
2359 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) {
2360 m = vm_page_lookup(obj, OFF_TO_IDX(off + toff));
2364 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK))
2365 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK);
2366 if (vm_page_is_valid(m,
2367 (vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0)
2370 VM_OBJECT_UNLOCK(obj);
2374 VM_OBJECT_UNLOCK(obj);
2381 * Sets the dirty range for a buffer based on the status of the dirty
2382 * bits in the pages comprising the buffer.
2384 * The range is limited to the size of the buffer.
2386 * This routine is primarily used by NFS, but is generalized for the
2390 vfs_setdirty(struct buf *bp)
2394 * Degenerate case - empty buffer
2397 if (bp->b_bufsize == 0)
2401 * We qualify the scan for modified pages on whether the
2402 * object has been flushed yet.
2405 if ((bp->b_flags & B_VMIO) == 0)
2408 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
2409 vfs_setdirty_locked_object(bp);
2410 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
2414 vfs_setdirty_locked_object(struct buf *bp)
2419 object = bp->b_bufobj->bo_object;
2420 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
2421 if (object->flags & (OBJ_MIGHTBEDIRTY|OBJ_CLEANING)) {
2422 vm_offset_t boffset;
2423 vm_offset_t eoffset;
2425 vm_page_lock_queues();
2427 * test the pages to see if they have been modified directly
2428 * by users through the VM system.
2430 for (i = 0; i < bp->b_npages; i++)
2431 vm_page_test_dirty(bp->b_pages[i]);
2434 * Calculate the encompassing dirty range, boffset and eoffset,
2435 * (eoffset - boffset) bytes.
2438 for (i = 0; i < bp->b_npages; i++) {
2439 if (bp->b_pages[i]->dirty)
2442 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK);
2444 for (i = bp->b_npages - 1; i >= 0; --i) {
2445 if (bp->b_pages[i]->dirty) {
2449 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK);
2451 vm_page_unlock_queues();
2453 * Fit it to the buffer.
2456 if (eoffset > bp->b_bcount)
2457 eoffset = bp->b_bcount;
2460 * If we have a good dirty range, merge with the existing
2464 if (boffset < eoffset) {
2465 if (bp->b_dirtyoff > boffset)
2466 bp->b_dirtyoff = boffset;
2467 if (bp->b_dirtyend < eoffset)
2468 bp->b_dirtyend = eoffset;
2476 * Get a block given a specified block and offset into a file/device.
2477 * The buffers B_DONE bit will be cleared on return, making it almost
2478 * ready for an I/O initiation. B_INVAL may or may not be set on
2479 * return. The caller should clear B_INVAL prior to initiating a
2482 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for
2483 * an existing buffer.
2485 * For a VMIO buffer, B_CACHE is modified according to the backing VM.
2486 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set
2487 * and then cleared based on the backing VM. If the previous buffer is
2488 * non-0-sized but invalid, B_CACHE will be cleared.
2490 * If getblk() must create a new buffer, the new buffer is returned with
2491 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which
2492 * case it is returned with B_INVAL clear and B_CACHE set based on the
2495 * getblk() also forces a bwrite() for any B_DELWRI buffer whos
2496 * B_CACHE bit is clear.
2498 * What this means, basically, is that the caller should use B_CACHE to
2499 * determine whether the buffer is fully valid or not and should clear
2500 * B_INVAL prior to issuing a read. If the caller intends to validate
2501 * the buffer by loading its data area with something, the caller needs
2502 * to clear B_INVAL. If the caller does this without issuing an I/O,
2503 * the caller should set B_CACHE ( as an optimization ), else the caller
2504 * should issue the I/O and biodone() will set B_CACHE if the I/O was
2505 * a write attempt or if it was a successfull read. If the caller
2506 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR
2507 * prior to issuing the READ. biodone() will *not* clear B_INVAL.
2510 getblk(struct vnode * vp, daddr_t blkno, int size, int slpflag, int slptimeo,
2517 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size);
2518 ASSERT_VOP_LOCKED(vp, "getblk");
2519 if (size > MAXBSIZE)
2520 panic("getblk: size(%d) > MAXBSIZE(%d)\n", size, MAXBSIZE);
2525 * Block if we are low on buffers. Certain processes are allowed
2526 * to completely exhaust the buffer cache.
2528 * If this check ever becomes a bottleneck it may be better to
2529 * move it into the else, when gbincore() fails. At the moment
2530 * it isn't a problem.
2532 * XXX remove if 0 sections (clean this up after its proven)
2534 if (numfreebuffers == 0) {
2535 if (TD_IS_IDLETHREAD(curthread))
2538 needsbuffer |= VFS_BIO_NEED_ANY;
2539 mtx_unlock(&nblock);
2543 bp = gbincore(bo, blkno);
2547 * Buffer is in-core. If the buffer is not busy, it must
2550 lockflags = LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK;
2552 if (flags & GB_LOCK_NOWAIT)
2553 lockflags |= LK_NOWAIT;
2555 error = BUF_TIMELOCK(bp, lockflags,
2556 BO_MTX(bo), "getblk", slpflag, slptimeo);
2559 * If we slept and got the lock we have to restart in case
2560 * the buffer changed identities.
2562 if (error == ENOLCK)
2564 /* We timed out or were interrupted. */
2569 * The buffer is locked. B_CACHE is cleared if the buffer is
2570 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set
2571 * and for a VMIO buffer B_CACHE is adjusted according to the
2574 if (bp->b_flags & B_INVAL)
2575 bp->b_flags &= ~B_CACHE;
2576 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0)
2577 bp->b_flags |= B_CACHE;
2581 * check for size inconsistancies for non-VMIO case.
2584 if (bp->b_bcount != size) {
2585 if ((bp->b_flags & B_VMIO) == 0 ||
2586 (size > bp->b_kvasize)) {
2587 if (bp->b_flags & B_DELWRI) {
2589 * If buffer is pinned and caller does
2590 * not want sleep waiting for it to be
2591 * unpinned, bail out
2593 if (bp->b_pin_count > 0) {
2594 if (flags & GB_LOCK_NOWAIT) {
2601 bp->b_flags |= B_NOCACHE;
2604 if (LIST_EMPTY(&bp->b_dep)) {
2605 bp->b_flags |= B_RELBUF;
2608 bp->b_flags |= B_NOCACHE;
2617 * If the size is inconsistant in the VMIO case, we can resize
2618 * the buffer. This might lead to B_CACHE getting set or
2619 * cleared. If the size has not changed, B_CACHE remains
2620 * unchanged from its previous state.
2623 if (bp->b_bcount != size)
2626 KASSERT(bp->b_offset != NOOFFSET,
2627 ("getblk: no buffer offset"));
2630 * A buffer with B_DELWRI set and B_CACHE clear must
2631 * be committed before we can return the buffer in
2632 * order to prevent the caller from issuing a read
2633 * ( due to B_CACHE not being set ) and overwriting
2636 * Most callers, including NFS and FFS, need this to
2637 * operate properly either because they assume they
2638 * can issue a read if B_CACHE is not set, or because
2639 * ( for example ) an uncached B_DELWRI might loop due
2640 * to softupdates re-dirtying the buffer. In the latter
2641 * case, B_CACHE is set after the first write completes,
2642 * preventing further loops.
2643 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE
2644 * above while extending the buffer, we cannot allow the
2645 * buffer to remain with B_CACHE set after the write
2646 * completes or it will represent a corrupt state. To
2647 * deal with this we set B_NOCACHE to scrap the buffer
2650 * We might be able to do something fancy, like setting
2651 * B_CACHE in bwrite() except if B_DELWRI is already set,
2652 * so the below call doesn't set B_CACHE, but that gets real
2653 * confusing. This is much easier.
2656 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) {
2657 bp->b_flags |= B_NOCACHE;
2661 bp->b_flags &= ~B_DONE;
2663 int bsize, maxsize, vmio;
2667 * Buffer is not in-core, create new buffer. The buffer
2668 * returned by getnewbuf() is locked. Note that the returned
2669 * buffer is also considered valid (not marked B_INVAL).
2673 * If the user does not want us to create the buffer, bail out
2676 if (flags & GB_NOCREAT)
2678 bsize = bo->bo_bsize;
2679 offset = blkno * bsize;
2680 vmio = vp->v_object != NULL;
2681 maxsize = vmio ? size + (offset & PAGE_MASK) : size;
2682 maxsize = imax(maxsize, bsize);
2684 bp = getnewbuf(vp, slpflag, slptimeo, size, maxsize, flags);
2686 if (slpflag || slptimeo)
2692 * This code is used to make sure that a buffer is not
2693 * created while the getnewbuf routine is blocked.
2694 * This can be a problem whether the vnode is locked or not.
2695 * If the buffer is created out from under us, we have to
2696 * throw away the one we just created.
2698 * Note: this must occur before we associate the buffer
2699 * with the vp especially considering limitations in
2700 * the splay tree implementation when dealing with duplicate
2704 if (gbincore(bo, blkno)) {
2706 bp->b_flags |= B_INVAL;
2712 * Insert the buffer into the hash, so that it can
2713 * be found by incore.
2715 bp->b_blkno = bp->b_lblkno = blkno;
2716 bp->b_offset = offset;
2721 * set B_VMIO bit. allocbuf() the buffer bigger. Since the
2722 * buffer size starts out as 0, B_CACHE will be set by
2723 * allocbuf() for the VMIO case prior to it testing the
2724 * backing store for validity.
2728 bp->b_flags |= B_VMIO;
2729 #if defined(VFS_BIO_DEBUG)
2730 if (vn_canvmio(vp) != TRUE)
2731 printf("getblk: VMIO on vnode type %d\n",
2734 KASSERT(vp->v_object == bp->b_bufobj->bo_object,
2735 ("ARGH! different b_bufobj->bo_object %p %p %p\n",
2736 bp, vp->v_object, bp->b_bufobj->bo_object));
2738 bp->b_flags &= ~B_VMIO;
2739 KASSERT(bp->b_bufobj->bo_object == NULL,
2740 ("ARGH! has b_bufobj->bo_object %p %p\n",
2741 bp, bp->b_bufobj->bo_object));
2745 bp->b_flags &= ~B_DONE;
2747 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp);
2748 BUF_ASSERT_HELD(bp);
2749 KASSERT(bp->b_bufobj == bo,
2750 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
2755 * Get an empty, disassociated buffer of given size. The buffer is initially
2759 geteblk(int size, int flags)
2764 maxsize = (size + BKVAMASK) & ~BKVAMASK;
2765 while ((bp = getnewbuf(NULL, 0, 0, size, maxsize, flags)) == NULL) {
2766 if ((flags & GB_NOWAIT_BD) &&
2767 (curthread->td_pflags & TDP_BUFNEED) != 0)
2771 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */
2772 BUF_ASSERT_HELD(bp);
2778 * This code constitutes the buffer memory from either anonymous system
2779 * memory (in the case of non-VMIO operations) or from an associated
2780 * VM object (in the case of VMIO operations). This code is able to
2781 * resize a buffer up or down.
2783 * Note that this code is tricky, and has many complications to resolve
2784 * deadlock or inconsistant data situations. Tread lightly!!!
2785 * There are B_CACHE and B_DELWRI interactions that must be dealt with by
2786 * the caller. Calling this code willy nilly can result in the loss of data.
2788 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with
2789 * B_CACHE for the non-VMIO case.
2793 allocbuf(struct buf *bp, int size)
2795 int newbsize, mbsize;
2798 BUF_ASSERT_HELD(bp);
2800 if (bp->b_kvasize < size)
2801 panic("allocbuf: buffer too small");
2803 if ((bp->b_flags & B_VMIO) == 0) {
2807 * Just get anonymous memory from the kernel. Don't
2808 * mess with B_CACHE.
2810 mbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1);
2811 if (bp->b_flags & B_MALLOC)
2814 newbsize = round_page(size);
2816 if (newbsize < bp->b_bufsize) {
2818 * malloced buffers are not shrunk
2820 if (bp->b_flags & B_MALLOC) {
2822 bp->b_bcount = size;
2824 free(bp->b_data, M_BIOBUF);
2825 if (bp->b_bufsize) {
2826 atomic_subtract_long(
2832 bp->b_saveaddr = bp->b_kvabase;
2833 bp->b_data = bp->b_saveaddr;
2835 bp->b_flags &= ~B_MALLOC;
2841 (vm_offset_t) bp->b_data + newbsize,
2842 (vm_offset_t) bp->b_data + bp->b_bufsize);
2843 } else if (newbsize > bp->b_bufsize) {
2845 * We only use malloced memory on the first allocation.
2846 * and revert to page-allocated memory when the buffer
2850 * There is a potential smp race here that could lead
2851 * to bufmallocspace slightly passing the max. It
2852 * is probably extremely rare and not worth worrying
2855 if ( (bufmallocspace < maxbufmallocspace) &&
2856 (bp->b_bufsize == 0) &&
2857 (mbsize <= PAGE_SIZE/2)) {
2859 bp->b_data = malloc(mbsize, M_BIOBUF, M_WAITOK);
2860 bp->b_bufsize = mbsize;
2861 bp->b_bcount = size;
2862 bp->b_flags |= B_MALLOC;
2863 atomic_add_long(&bufmallocspace, mbsize);
2869 * If the buffer is growing on its other-than-first allocation,
2870 * then we revert to the page-allocation scheme.
2872 if (bp->b_flags & B_MALLOC) {
2873 origbuf = bp->b_data;
2874 origbufsize = bp->b_bufsize;
2875 bp->b_data = bp->b_kvabase;
2876 if (bp->b_bufsize) {
2877 atomic_subtract_long(&bufmallocspace,
2882 bp->b_flags &= ~B_MALLOC;
2883 newbsize = round_page(newbsize);
2887 (vm_offset_t) bp->b_data + bp->b_bufsize,
2888 (vm_offset_t) bp->b_data + newbsize);
2890 bcopy(origbuf, bp->b_data, origbufsize);
2891 free(origbuf, M_BIOBUF);
2897 newbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1);
2898 desiredpages = (size == 0) ? 0 :
2899 num_pages((bp->b_offset & PAGE_MASK) + newbsize);
2901 if (bp->b_flags & B_MALLOC)
2902 panic("allocbuf: VMIO buffer can't be malloced");
2904 * Set B_CACHE initially if buffer is 0 length or will become
2907 if (size == 0 || bp->b_bufsize == 0)
2908 bp->b_flags |= B_CACHE;
2910 if (newbsize < bp->b_bufsize) {
2912 * DEV_BSIZE aligned new buffer size is less then the
2913 * DEV_BSIZE aligned existing buffer size. Figure out
2914 * if we have to remove any pages.
2916 if (desiredpages < bp->b_npages) {
2919 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
2920 vm_page_lock_queues();
2921 for (i = desiredpages; i < bp->b_npages; i++) {
2923 * the page is not freed here -- it
2924 * is the responsibility of
2925 * vnode_pager_setsize
2928 KASSERT(m != bogus_page,
2929 ("allocbuf: bogus page found"));
2930 while (vm_page_sleep_if_busy(m, TRUE, "biodep"))
2931 vm_page_lock_queues();
2933 bp->b_pages[i] = NULL;
2934 vm_page_unwire(m, 0);
2936 vm_page_unlock_queues();
2937 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
2938 pmap_qremove((vm_offset_t) trunc_page((vm_offset_t)bp->b_data) +
2939 (desiredpages << PAGE_SHIFT), (bp->b_npages - desiredpages));
2940 bp->b_npages = desiredpages;
2942 } else if (size > bp->b_bcount) {
2944 * We are growing the buffer, possibly in a
2945 * byte-granular fashion.
2953 * Step 1, bring in the VM pages from the object,
2954 * allocating them if necessary. We must clear
2955 * B_CACHE if these pages are not valid for the
2956 * range covered by the buffer.
2960 obj = bp->b_bufobj->bo_object;
2962 VM_OBJECT_LOCK(obj);
2963 while (bp->b_npages < desiredpages) {
2967 pi = OFF_TO_IDX(bp->b_offset) + bp->b_npages;
2968 if ((m = vm_page_lookup(obj, pi)) == NULL) {
2970 * note: must allocate system pages
2971 * since blocking here could intefere
2972 * with paging I/O, no matter which
2975 m = vm_page_alloc(obj, pi,
2976 VM_ALLOC_NOBUSY | VM_ALLOC_SYSTEM |
2979 atomic_add_int(&vm_pageout_deficit,
2980 desiredpages - bp->b_npages);
2981 VM_OBJECT_UNLOCK(obj);
2983 VM_OBJECT_LOCK(obj);
2986 bp->b_flags &= ~B_CACHE;
2987 bp->b_pages[bp->b_npages] = m;
2994 * We found a page. If we have to sleep on it,
2995 * retry because it might have gotten freed out
2998 * We can only test VPO_BUSY here. Blocking on
2999 * m->busy might lead to a deadlock:
3001 * vm_fault->getpages->cluster_read->allocbuf
3004 if (vm_page_sleep_if_busy(m, FALSE, "pgtblk"))
3008 * We have a good page.
3010 vm_page_lock_queues();
3012 vm_page_unlock_queues();
3013 bp->b_pages[bp->b_npages] = m;
3018 * Step 2. We've loaded the pages into the buffer,
3019 * we have to figure out if we can still have B_CACHE
3020 * set. Note that B_CACHE is set according to the
3021 * byte-granular range ( bcount and size ), new the
3022 * aligned range ( newbsize ).
3024 * The VM test is against m->valid, which is DEV_BSIZE
3025 * aligned. Needless to say, the validity of the data
3026 * needs to also be DEV_BSIZE aligned. Note that this
3027 * fails with NFS if the server or some other client
3028 * extends the file's EOF. If our buffer is resized,
3029 * B_CACHE may remain set! XXX
3032 toff = bp->b_bcount;
3033 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK);
3035 while ((bp->b_flags & B_CACHE) && toff < size) {
3038 if (tinc > (size - toff))
3041 pi = ((bp->b_offset & PAGE_MASK) + toff) >>
3054 VM_OBJECT_UNLOCK(obj);
3057 * Step 3, fixup the KVM pmap. Remember that
3058 * bp->b_data is relative to bp->b_offset, but
3059 * bp->b_offset may be offset into the first page.
3062 bp->b_data = (caddr_t)
3063 trunc_page((vm_offset_t)bp->b_data);
3065 (vm_offset_t)bp->b_data,
3070 bp->b_data = (caddr_t)((vm_offset_t)bp->b_data |
3071 (vm_offset_t)(bp->b_offset & PAGE_MASK));
3074 if (newbsize < bp->b_bufsize)
3076 bp->b_bufsize = newbsize; /* actual buffer allocation */
3077 bp->b_bcount = size; /* requested buffer size */
3082 biodone(struct bio *bp)
3085 void (*done)(struct bio *);
3087 mtxp = mtx_pool_find(mtxpool_sleep, bp);
3089 bp->bio_flags |= BIO_DONE;
3090 done = bp->bio_done;
3099 * Wait for a BIO to finish.
3101 * XXX: resort to a timeout for now. The optimal locking (if any) for this
3102 * case is not yet clear.
3105 biowait(struct bio *bp, const char *wchan)
3109 mtxp = mtx_pool_find(mtxpool_sleep, bp);
3111 while ((bp->bio_flags & BIO_DONE) == 0)
3112 msleep(bp, mtxp, PRIBIO, wchan, hz / 10);
3114 if (bp->bio_error != 0)
3115 return (bp->bio_error);
3116 if (!(bp->bio_flags & BIO_ERROR))
3122 biofinish(struct bio *bp, struct devstat *stat, int error)
3126 bp->bio_error = error;
3127 bp->bio_flags |= BIO_ERROR;
3130 devstat_end_transaction_bio(stat, bp);
3137 * Wait for buffer I/O completion, returning error status. The buffer
3138 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR
3139 * error and cleared.
3142 bufwait(struct buf *bp)
3144 if (bp->b_iocmd == BIO_READ)
3145 bwait(bp, PRIBIO, "biord");
3147 bwait(bp, PRIBIO, "biowr");
3148 if (bp->b_flags & B_EINTR) {
3149 bp->b_flags &= ~B_EINTR;
3152 if (bp->b_ioflags & BIO_ERROR) {
3153 return (bp->b_error ? bp->b_error : EIO);
3160 * Call back function from struct bio back up to struct buf.
3163 bufdonebio(struct bio *bip)
3167 bp = bip->bio_caller2;
3168 bp->b_resid = bp->b_bcount - bip->bio_completed;
3169 bp->b_resid = bip->bio_resid; /* XXX: remove */
3170 bp->b_ioflags = bip->bio_flags;
3171 bp->b_error = bip->bio_error;
3173 bp->b_ioflags |= BIO_ERROR;
3179 dev_strategy(struct cdev *dev, struct buf *bp)
3184 if ((!bp->b_iocmd) || (bp->b_iocmd & (bp->b_iocmd - 1)))
3185 panic("b_iocmd botch");
3190 /* Try again later */
3191 tsleep(&bp, PRIBIO, "dev_strat", hz/10);
3193 bip->bio_cmd = bp->b_iocmd;
3194 bip->bio_offset = bp->b_iooffset;
3195 bip->bio_length = bp->b_bcount;
3196 bip->bio_bcount = bp->b_bcount; /* XXX: remove */
3197 bip->bio_data = bp->b_data;
3198 bip->bio_done = bufdonebio;
3199 bip->bio_caller2 = bp;
3201 KASSERT(dev->si_refcount > 0,
3202 ("dev_strategy on un-referenced struct cdev *(%s)",
3204 csw = dev_refthread(dev);
3207 bp->b_error = ENXIO;
3208 bp->b_ioflags = BIO_ERROR;
3212 (*csw->d_strategy)(bip);
3219 * Finish I/O on a buffer, optionally calling a completion function.
3220 * This is usually called from an interrupt so process blocking is
3223 * biodone is also responsible for setting B_CACHE in a B_VMIO bp.
3224 * In a non-VMIO bp, B_CACHE will be set on the next getblk()
3225 * assuming B_INVAL is clear.
3227 * For the VMIO case, we set B_CACHE if the op was a read and no
3228 * read error occured, or if the op was a write. B_CACHE is never
3229 * set if the buffer is invalid or otherwise uncacheable.
3231 * biodone does not mess with B_INVAL, allowing the I/O routine or the
3232 * initiator to leave B_INVAL set to brelse the buffer out of existance
3233 * in the biodone routine.
3236 bufdone(struct buf *bp)
3238 struct bufobj *dropobj;
3239 void (*biodone)(struct buf *);
3241 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
3244 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp));
3245 BUF_ASSERT_HELD(bp);
3247 runningbufwakeup(bp);
3248 if (bp->b_iocmd == BIO_WRITE)
3249 dropobj = bp->b_bufobj;
3250 /* call optional completion function if requested */
3251 if (bp->b_iodone != NULL) {
3252 biodone = bp->b_iodone;
3253 bp->b_iodone = NULL;
3256 bufobj_wdrop(dropobj);
3263 bufobj_wdrop(dropobj);
3267 bufdone_finish(struct buf *bp)
3269 BUF_ASSERT_HELD(bp);
3271 if (!LIST_EMPTY(&bp->b_dep))
3274 if (bp->b_flags & B_VMIO) {
3280 struct vnode *vp = bp->b_vp;
3282 obj = bp->b_bufobj->bo_object;
3284 #if defined(VFS_BIO_DEBUG)
3285 mp_fixme("usecount and vflag accessed without locks.");
3286 if (vp->v_usecount == 0) {
3287 panic("biodone: zero vnode ref count");
3290 KASSERT(vp->v_object != NULL,
3291 ("biodone: vnode %p has no vm_object", vp));
3294 foff = bp->b_offset;
3295 KASSERT(bp->b_offset != NOOFFSET,
3296 ("biodone: no buffer offset"));
3298 VM_OBJECT_LOCK(obj);
3299 #if defined(VFS_BIO_DEBUG)
3300 if (obj->paging_in_progress < bp->b_npages) {
3301 printf("biodone: paging in progress(%d) < bp->b_npages(%d)\n",
3302 obj->paging_in_progress, bp->b_npages);
3307 * Set B_CACHE if the op was a normal read and no error
3308 * occured. B_CACHE is set for writes in the b*write()
3311 iosize = bp->b_bcount - bp->b_resid;
3312 if (bp->b_iocmd == BIO_READ &&
3313 !(bp->b_flags & (B_INVAL|B_NOCACHE)) &&
3314 !(bp->b_ioflags & BIO_ERROR)) {
3315 bp->b_flags |= B_CACHE;
3317 for (i = 0; i < bp->b_npages; i++) {
3321 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff;
3326 * cleanup bogus pages, restoring the originals
3329 if (m == bogus_page) {
3331 m = vm_page_lookup(obj, OFF_TO_IDX(foff));
3333 panic("biodone: page disappeared!");
3335 pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
3336 bp->b_pages, bp->b_npages);
3338 #if defined(VFS_BIO_DEBUG)
3339 if (OFF_TO_IDX(foff) != m->pindex) {
3341 "biodone: foff(%jd)/m->pindex(%ju) mismatch\n",
3342 (intmax_t)foff, (uintmax_t)m->pindex);
3347 * In the write case, the valid and clean bits are
3348 * already changed correctly ( see bdwrite() ), so we
3349 * only need to do this here in the read case.
3351 if ((bp->b_iocmd == BIO_READ) && !bogusflag && resid > 0) {
3352 KASSERT((m->dirty & vm_page_bits(foff &
3353 PAGE_MASK, resid)) == 0, ("bufdone_finish:"
3354 " page %p has unexpected dirty bits", m));
3355 vfs_page_set_valid(bp, foff, m);
3359 * when debugging new filesystems or buffer I/O methods, this
3360 * is the most common error that pops up. if you see this, you
3361 * have not set the page busy flag correctly!!!
3364 printf("biodone: page busy < 0, "
3365 "pindex: %d, foff: 0x(%x,%x), "
3366 "resid: %d, index: %d\n",
3367 (int) m->pindex, (int)(foff >> 32),
3368 (int) foff & 0xffffffff, resid, i);
3369 if (!vn_isdisk(vp, NULL))
3370 printf(" iosize: %jd, lblkno: %jd, flags: 0x%x, npages: %d\n",
3371 (intmax_t)bp->b_vp->v_mount->mnt_stat.f_iosize,
3372 (intmax_t) bp->b_lblkno,
3373 bp->b_flags, bp->b_npages);
3375 printf(" VDEV, lblkno: %jd, flags: 0x%x, npages: %d\n",
3376 (intmax_t) bp->b_lblkno,
3377 bp->b_flags, bp->b_npages);
3378 printf(" valid: 0x%lx, dirty: 0x%lx, wired: %d\n",
3379 (u_long)m->valid, (u_long)m->dirty,
3381 panic("biodone: page busy < 0\n");
3383 vm_page_io_finish(m);
3384 vm_object_pip_subtract(obj, 1);
3385 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
3388 vm_object_pip_wakeupn(obj, 0);
3389 VM_OBJECT_UNLOCK(obj);
3393 * For asynchronous completions, release the buffer now. The brelse
3394 * will do a wakeup there if necessary - so no need to do a wakeup
3395 * here in the async case. The sync case always needs to do a wakeup.
3398 if (bp->b_flags & B_ASYNC) {
3399 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || (bp->b_ioflags & BIO_ERROR))
3408 * This routine is called in lieu of iodone in the case of
3409 * incomplete I/O. This keeps the busy status for pages
3413 vfs_unbusy_pages(struct buf *bp)
3419 runningbufwakeup(bp);
3420 if (!(bp->b_flags & B_VMIO))
3423 obj = bp->b_bufobj->bo_object;
3424 VM_OBJECT_LOCK(obj);
3425 for (i = 0; i < bp->b_npages; i++) {
3427 if (m == bogus_page) {
3428 m = vm_page_lookup(obj, OFF_TO_IDX(bp->b_offset) + i);
3430 panic("vfs_unbusy_pages: page missing\n");
3432 pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
3433 bp->b_pages, bp->b_npages);
3435 vm_object_pip_subtract(obj, 1);
3436 vm_page_io_finish(m);
3438 vm_object_pip_wakeupn(obj, 0);
3439 VM_OBJECT_UNLOCK(obj);
3443 * vfs_page_set_valid:
3445 * Set the valid bits in a page based on the supplied offset. The
3446 * range is restricted to the buffer's size.
3448 * This routine is typically called after a read completes.
3451 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m)
3456 * Compute the end offset, eoff, such that [off, eoff) does not span a
3457 * page boundary and eoff is not greater than the end of the buffer.
3458 * The end of the buffer, in this case, is our file EOF, not the
3459 * allocation size of the buffer.
3461 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK;
3462 if (eoff > bp->b_offset + bp->b_bcount)
3463 eoff = bp->b_offset + bp->b_bcount;
3466 * Set valid range. This is typically the entire buffer and thus the
3470 vm_page_set_valid(m, off & PAGE_MASK, eoff - off);
3474 * vfs_page_set_validclean:
3476 * Set the valid bits and clear the dirty bits in a page based on the
3477 * supplied offset. The range is restricted to the buffer's size.
3480 vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m)
3482 vm_ooffset_t soff, eoff;
3484 mtx_assert(&vm_page_queue_mtx, MA_OWNED);
3486 * Start and end offsets in buffer. eoff - soff may not cross a
3487 * page boundry or cross the end of the buffer. The end of the
3488 * buffer, in this case, is our file EOF, not the allocation size
3492 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK;
3493 if (eoff > bp->b_offset + bp->b_bcount)
3494 eoff = bp->b_offset + bp->b_bcount;
3497 * Set valid range. This is typically the entire buffer and thus the
3501 vm_page_set_validclean(
3503 (vm_offset_t) (soff & PAGE_MASK),
3504 (vm_offset_t) (eoff - soff)
3510 * This routine is called before a device strategy routine.
3511 * It is used to tell the VM system that paging I/O is in
3512 * progress, and treat the pages associated with the buffer
3513 * almost as being VPO_BUSY. Also the object paging_in_progress
3514 * flag is handled to make sure that the object doesn't become
3517 * Since I/O has not been initiated yet, certain buffer flags
3518 * such as BIO_ERROR or B_INVAL may be in an inconsistant state
3519 * and should be ignored.
3522 vfs_busy_pages(struct buf *bp, int clear_modify)
3529 if (!(bp->b_flags & B_VMIO))
3532 obj = bp->b_bufobj->bo_object;
3533 foff = bp->b_offset;
3534 KASSERT(bp->b_offset != NOOFFSET,
3535 ("vfs_busy_pages: no buffer offset"));
3536 VM_OBJECT_LOCK(obj);
3537 if (bp->b_bufsize != 0)
3538 vfs_setdirty_locked_object(bp);
3540 for (i = 0; i < bp->b_npages; i++) {
3543 if (vm_page_sleep_if_busy(m, FALSE, "vbpage"))
3548 vm_page_lock_queues();
3549 for (i = 0; i < bp->b_npages; i++) {
3552 if ((bp->b_flags & B_CLUSTER) == 0) {
3553 vm_object_pip_add(obj, 1);
3554 vm_page_io_start(m);
3557 * When readying a buffer for a read ( i.e
3558 * clear_modify == 0 ), it is important to do
3559 * bogus_page replacement for valid pages in
3560 * partially instantiated buffers. Partially
3561 * instantiated buffers can, in turn, occur when
3562 * reconstituting a buffer from its VM backing store
3563 * base. We only have to do this if B_CACHE is
3564 * clear ( which causes the I/O to occur in the
3565 * first place ). The replacement prevents the read
3566 * I/O from overwriting potentially dirty VM-backed
3567 * pages. XXX bogus page replacement is, uh, bogus.
3568 * It may not work properly with small-block devices.
3569 * We need to find a better way.
3572 pmap_remove_write(m);
3573 vfs_page_set_validclean(bp, foff, m);
3574 } else if (m->valid == VM_PAGE_BITS_ALL &&
3575 (bp->b_flags & B_CACHE) == 0) {
3576 bp->b_pages[i] = bogus_page;
3579 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
3582 vm_page_unlock_queues();
3583 VM_OBJECT_UNLOCK(obj);
3585 pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
3586 bp->b_pages, bp->b_npages);
3590 * Tell the VM system that the pages associated with this buffer
3591 * are clean. This is used for delayed writes where the data is
3592 * going to go to disk eventually without additional VM intevention.
3594 * Note that while we only really need to clean through to b_bcount, we
3595 * just go ahead and clean through to b_bufsize.
3598 vfs_clean_pages(struct buf *bp)
3601 vm_ooffset_t foff, noff, eoff;
3604 if (!(bp->b_flags & B_VMIO))
3607 foff = bp->b_offset;
3608 KASSERT(bp->b_offset != NOOFFSET,
3609 ("vfs_clean_pages: no buffer offset"));
3610 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
3611 vm_page_lock_queues();
3612 for (i = 0; i < bp->b_npages; i++) {
3614 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
3617 if (eoff > bp->b_offset + bp->b_bufsize)
3618 eoff = bp->b_offset + bp->b_bufsize;
3619 vfs_page_set_validclean(bp, foff, m);
3620 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */
3623 vm_page_unlock_queues();
3624 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
3628 * vfs_bio_set_valid:
3630 * Set the range within the buffer to valid. The range is
3631 * relative to the beginning of the buffer, b_offset. Note that
3632 * b_offset itself may be offset from the beginning of the first
3636 vfs_bio_set_valid(struct buf *bp, int base, int size)
3641 if (!(bp->b_flags & B_VMIO))
3645 * Fixup base to be relative to beginning of first page.
3646 * Set initial n to be the maximum number of bytes in the
3647 * first page that can be validated.
3649 base += (bp->b_offset & PAGE_MASK);
3650 n = PAGE_SIZE - (base & PAGE_MASK);
3652 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
3653 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) {
3657 vm_page_set_valid(m, base & PAGE_MASK, n);
3662 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
3666 * vfs_bio_set_validclean:
3668 * Set the range within the buffer to valid and clean. The range is
3669 * relative to the beginning of the buffer, b_offset. Note that b_offset
3670 * itself may be offset from the beginning of the first page.
3675 vfs_bio_set_validclean(struct buf *bp, int base, int size)
3680 if (!(bp->b_flags & B_VMIO))
3683 * Fixup base to be relative to beginning of first page.
3684 * Set initial n to be the maximum number of bytes in the
3685 * first page that can be validated.
3688 base += (bp->b_offset & PAGE_MASK);
3689 n = PAGE_SIZE - (base & PAGE_MASK);
3691 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
3692 vm_page_lock_queues();
3693 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) {
3697 vm_page_set_validclean(m, base & PAGE_MASK, n);
3702 vm_page_unlock_queues();
3703 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
3709 * If the specified buffer is a non-VMIO buffer, clear the entire
3710 * buffer. If the specified buffer is a VMIO buffer, clear and
3711 * validate only the previously invalid portions of the buffer.
3712 * This routine essentially fakes an I/O, so we need to clear
3713 * BIO_ERROR and B_INVAL.
3715 * Note that while we only theoretically need to clear through b_bcount,
3716 * we go ahead and clear through b_bufsize.
3719 vfs_bio_clrbuf(struct buf *bp)
3724 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) {
3728 bp->b_flags &= ~B_INVAL;
3729 bp->b_ioflags &= ~BIO_ERROR;
3730 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
3731 if ((bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE) &&
3732 (bp->b_offset & PAGE_MASK) == 0) {
3733 if (bp->b_pages[0] == bogus_page)
3735 mask = (1 << (bp->b_bufsize / DEV_BSIZE)) - 1;
3736 VM_OBJECT_LOCK_ASSERT(bp->b_pages[0]->object, MA_OWNED);
3737 if ((bp->b_pages[0]->valid & mask) == mask)
3739 if ((bp->b_pages[0]->valid & mask) == 0) {
3740 bzero(bp->b_data, bp->b_bufsize);
3741 bp->b_pages[0]->valid |= mask;
3745 ea = sa = bp->b_data;
3746 for(i = 0; i < bp->b_npages; i++, sa = ea) {
3747 ea = (caddr_t)trunc_page((vm_offset_t)sa + PAGE_SIZE);
3748 ea = (caddr_t)(vm_offset_t)ulmin(
3749 (u_long)(vm_offset_t)ea,
3750 (u_long)(vm_offset_t)bp->b_data + bp->b_bufsize);
3751 if (bp->b_pages[i] == bogus_page)
3753 j = ((vm_offset_t)sa & PAGE_MASK) / DEV_BSIZE;
3754 mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j;
3755 VM_OBJECT_LOCK_ASSERT(bp->b_pages[i]->object, MA_OWNED);
3756 if ((bp->b_pages[i]->valid & mask) == mask)
3758 if ((bp->b_pages[i]->valid & mask) == 0)
3761 for (; sa < ea; sa += DEV_BSIZE, j++) {
3762 if ((bp->b_pages[i]->valid & (1 << j)) == 0)
3763 bzero(sa, DEV_BSIZE);
3766 bp->b_pages[i]->valid |= mask;
3769 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
3774 * vm_hold_load_pages and vm_hold_free_pages get pages into
3775 * a buffers address space. The pages are anonymous and are
3776 * not associated with a file object.
3779 vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to)
3785 to = round_page(to);
3786 from = round_page(from);
3787 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT;
3789 VM_OBJECT_LOCK(kernel_object);
3790 for (pg = from; pg < to; pg += PAGE_SIZE, index++) {
3793 * note: must allocate system pages since blocking here
3794 * could intefere with paging I/O, no matter which
3797 p = vm_page_alloc(kernel_object,
3798 ((pg - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT),
3799 VM_ALLOC_NOBUSY | VM_ALLOC_SYSTEM | VM_ALLOC_WIRED);
3801 atomic_add_int(&vm_pageout_deficit,
3802 (to - pg) >> PAGE_SHIFT);
3803 VM_OBJECT_UNLOCK(kernel_object);
3805 VM_OBJECT_LOCK(kernel_object);
3808 p->valid = VM_PAGE_BITS_ALL;
3809 pmap_qenter(pg, &p, 1);
3810 bp->b_pages[index] = p;
3812 VM_OBJECT_UNLOCK(kernel_object);
3813 bp->b_npages = index;
3816 /* Return pages associated with this buf to the vm system */
3818 vm_hold_free_pages(struct buf *bp, vm_offset_t from, vm_offset_t to)
3822 int index, newnpages;
3824 from = round_page(from);
3825 to = round_page(to);
3826 newnpages = index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT;
3828 VM_OBJECT_LOCK(kernel_object);
3829 for (pg = from; pg < to; pg += PAGE_SIZE, index++) {
3830 p = bp->b_pages[index];
3831 if (p && (index < bp->b_npages)) {
3834 "vm_hold_free_pages: blkno: %jd, lblkno: %jd\n",
3835 (intmax_t)bp->b_blkno,
3836 (intmax_t)bp->b_lblkno);
3838 bp->b_pages[index] = NULL;
3839 pmap_qremove(pg, 1);
3840 vm_page_lock_queues();
3841 vm_page_unwire(p, 0);
3843 vm_page_unlock_queues();
3846 VM_OBJECT_UNLOCK(kernel_object);
3847 bp->b_npages = newnpages;
3851 * Map an IO request into kernel virtual address space.
3853 * All requests are (re)mapped into kernel VA space.
3854 * Notice that we use b_bufsize for the size of the buffer
3855 * to be mapped. b_bcount might be modified by the driver.
3857 * Note that even if the caller determines that the address space should
3858 * be valid, a race or a smaller-file mapped into a larger space may
3859 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST
3860 * check the return value.
3863 vmapbuf(struct buf *bp)
3869 struct pmap *pmap = &curproc->p_vmspace->vm_pmap;
3871 if (bp->b_bufsize < 0)
3873 prot = VM_PROT_READ;
3874 if (bp->b_iocmd == BIO_READ)
3875 prot |= VM_PROT_WRITE; /* Less backwards than it looks */
3876 for (addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data), pidx = 0;
3877 addr < bp->b_data + bp->b_bufsize;
3878 addr += PAGE_SIZE, pidx++) {
3880 * Do the vm_fault if needed; do the copy-on-write thing
3881 * when reading stuff off device into memory.
3883 * NOTE! Must use pmap_extract() because addr may be in
3884 * the userland address space, and kextract is only guarenteed
3885 * to work for the kernland address space (see: sparc64 port).
3888 if (vm_fault_quick(addr >= bp->b_data ? addr : bp->b_data,
3890 vm_page_lock_queues();
3891 for (i = 0; i < pidx; ++i) {
3892 vm_page_unhold(bp->b_pages[i]);
3893 bp->b_pages[i] = NULL;
3895 vm_page_unlock_queues();
3898 m = pmap_extract_and_hold(pmap, (vm_offset_t)addr, prot);
3901 bp->b_pages[pidx] = m;
3903 if (pidx > btoc(MAXPHYS))
3904 panic("vmapbuf: mapped more than MAXPHYS");
3905 pmap_qenter((vm_offset_t)bp->b_saveaddr, bp->b_pages, pidx);
3907 kva = bp->b_saveaddr;
3908 bp->b_npages = pidx;
3909 bp->b_saveaddr = bp->b_data;
3910 bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
3915 * Free the io map PTEs associated with this IO operation.
3916 * We also invalidate the TLB entries and restore the original b_addr.
3919 vunmapbuf(struct buf *bp)
3924 npages = bp->b_npages;
3925 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages);
3926 vm_page_lock_queues();
3927 for (pidx = 0; pidx < npages; pidx++)
3928 vm_page_unhold(bp->b_pages[pidx]);
3929 vm_page_unlock_queues();
3931 bp->b_data = bp->b_saveaddr;
3935 bdone(struct buf *bp)
3939 mtxp = mtx_pool_find(mtxpool_sleep, bp);
3941 bp->b_flags |= B_DONE;
3947 bwait(struct buf *bp, u_char pri, const char *wchan)
3951 mtxp = mtx_pool_find(mtxpool_sleep, bp);
3953 while ((bp->b_flags & B_DONE) == 0)
3954 msleep(bp, mtxp, pri, wchan, 0);
3959 bufsync(struct bufobj *bo, int waitfor)
3962 return (VOP_FSYNC(bo->__bo_vnode, waitfor, curthread));
3966 bufstrategy(struct bufobj *bo, struct buf *bp)
3972 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy"));
3973 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
3974 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp));
3975 i = VOP_STRATEGY(vp, bp);
3976 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp));
3980 bufobj_wrefl(struct bufobj *bo)
3983 KASSERT(bo != NULL, ("NULL bo in bufobj_wref"));
3984 ASSERT_BO_LOCKED(bo);
3989 bufobj_wref(struct bufobj *bo)
3992 KASSERT(bo != NULL, ("NULL bo in bufobj_wref"));
3999 bufobj_wdrop(struct bufobj *bo)
4002 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop"));
4004 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count"));
4005 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) {
4006 bo->bo_flag &= ~BO_WWAIT;
4007 wakeup(&bo->bo_numoutput);
4013 bufobj_wwait(struct bufobj *bo, int slpflag, int timeo)
4017 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait"));
4018 ASSERT_BO_LOCKED(bo);
4020 while (bo->bo_numoutput) {
4021 bo->bo_flag |= BO_WWAIT;
4022 error = msleep(&bo->bo_numoutput, BO_MTX(bo),
4023 slpflag | (PRIBIO + 1), "bo_wwait", timeo);
4031 bpin(struct buf *bp)
4035 mtxp = mtx_pool_find(mtxpool_sleep, bp);
4042 bunpin(struct buf *bp)
4046 mtxp = mtx_pool_find(mtxpool_sleep, bp);
4048 if (--bp->b_pin_count == 0)
4054 bunpin_wait(struct buf *bp)
4058 mtxp = mtx_pool_find(mtxpool_sleep, bp);
4060 while (bp->b_pin_count > 0)
4061 msleep(bp, mtxp, PRIBIO, "bwunpin", 0);
4065 #include "opt_ddb.h"
4067 #include <ddb/ddb.h>
4069 /* DDB command to show buffer data */
4070 DB_SHOW_COMMAND(buffer, db_show_buffer)
4073 struct buf *bp = (struct buf *)addr;
4076 db_printf("usage: show buffer <addr>\n");
4080 db_printf("buf at %p\n", bp);
4081 db_printf("b_flags = 0x%b\n", (u_int)bp->b_flags, PRINT_BUF_FLAGS);
4083 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n"
4084 "b_bufobj = (%p), b_data = %p, b_blkno = %jd, b_dep = %p\n",
4085 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid,
4086 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno,
4087 bp->b_dep.lh_first);
4090 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages);
4091 for (i = 0; i < bp->b_npages; i++) {
4094 db_printf("(%p, 0x%lx, 0x%lx)", (void *)m->object,
4095 (u_long)m->pindex, (u_long)VM_PAGE_TO_PHYS(m));
4096 if ((i + 1) < bp->b_npages)
4102 lockmgr_printinfo(&bp->b_lock);
4105 DB_SHOW_COMMAND(lockedbufs, lockedbufs)
4110 for (i = 0; i < nbuf; i++) {
4112 if (BUF_ISLOCKED(bp)) {
4113 db_show_buffer((uintptr_t)bp, 1, 0, NULL);
4119 DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs)
4125 db_printf("usage: show vnodebufs <addr>\n");
4128 vp = (struct vnode *)addr;
4129 db_printf("Clean buffers:\n");
4130 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) {
4131 db_show_buffer((uintptr_t)bp, 1, 0, NULL);
4134 db_printf("Dirty buffers:\n");
4135 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) {
4136 db_show_buffer((uintptr_t)bp, 1, 0, NULL);