vfs_bio.c revision 260354
11573Srgrimes/*- 21573Srgrimes * Copyright (c) 2004 Poul-Henning Kamp 31573Srgrimes * Copyright (c) 1994,1997 John S. Dyson 41573Srgrimes * Copyright (c) 2013 The FreeBSD Foundation 51573Srgrimes * All rights reserved. 61573Srgrimes * 71573Srgrimes * Portions of this software were developed by Konstantin Belousov 81573Srgrimes * under sponsorship from the FreeBSD Foundation. 91573Srgrimes * 101573Srgrimes * Redistribution and use in source and binary forms, with or without 111573Srgrimes * modification, are permitted provided that the following conditions 121573Srgrimes * are met: 131573Srgrimes * 1. Redistributions of source code must retain the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer. 151573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 161573Srgrimes * notice, this list of conditions and the following disclaimer in the 171573Srgrimes * documentation and/or other materials provided with the distribution. 181573Srgrimes * 191573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 201573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 211573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 221573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 231573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 241573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 251573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 261573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 271573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 281573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 291573Srgrimes * SUCH DAMAGE. 301573Srgrimes */ 311573Srgrimes 321573Srgrimes/* 331573Srgrimes * this file contains a new buffer I/O scheme implementing a coherent 341573Srgrimes * VM object and buffer cache scheme. Pains have been taken to make 351573Srgrimes * sure that the performance degradation associated with schemes such 3692986Sobrien * as this is not realized. 3792986Sobrien * 3892986Sobrien * Author: John S. Dyson 391573Srgrimes * Significant help during the development and debugging phases 401573Srgrimes * had been provided by David Greenman, also of the FreeBSD core team. 411573Srgrimes * 421573Srgrimes * see man buf(9) for more info. 431573Srgrimes */ 441573Srgrimes 451573Srgrimes#include <sys/cdefs.h> 461573Srgrimes__FBSDID("$FreeBSD: stable/10/sys/kern/vfs_bio.c 260354 2014-01-05 23:00:38Z mav $"); 471573Srgrimes 481573Srgrimes#include <sys/param.h> 491573Srgrimes#include <sys/systm.h> 501573Srgrimes#include <sys/bio.h> 511573Srgrimes#include <sys/conf.h> 521573Srgrimes#include <sys/buf.h> 531573Srgrimes#include <sys/devicestat.h> 541573Srgrimes#include <sys/eventhandler.h> 551573Srgrimes#include <sys/fail.h> 561573Srgrimes#include <sys/limits.h> 571573Srgrimes#include <sys/lock.h> 581573Srgrimes#include <sys/malloc.h> 591573Srgrimes#include <sys/mount.h> 601573Srgrimes#include <sys/mutex.h> 611573Srgrimes#include <sys/kernel.h> 621573Srgrimes#include <sys/kthread.h> 631573Srgrimes#include <sys/proc.h> 641573Srgrimes#include <sys/resourcevar.h> 651573Srgrimes#include <sys/rwlock.h> 661573Srgrimes#include <sys/sysctl.h> 671573Srgrimes#include <sys/vmem.h> 68132019Stjr#include <sys/vmmeter.h> 69132019Stjr#include <sys/vnode.h> 70132019Stjr#include <geom/geom.h> 71132019Stjr#include <vm/vm.h> 72132019Stjr#include <vm/vm_param.h> 73132019Stjr#include <vm/vm_kern.h> 74132019Stjr#include <vm/vm_pageout.h> 75132019Stjr#include <vm/vm_page.h> 76132019Stjr#include <vm/vm_object.h> 77132019Stjr#include <vm/vm_extern.h> 78132019Stjr#include <vm/vm_map.h> 791573Srgrimes#include "opt_compat.h" 801573Srgrimes#include "opt_directio.h" 811573Srgrimes#include "opt_swap.h" 821573Srgrimes 831573Srgrimesstatic MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer"); 841573Srgrimes 851573Srgrimesstruct bio_ops bioops; /* I/O operation notification */ 861573Srgrimes 871573Srgrimesstruct buf_ops buf_ops_bio = { 881573Srgrimes .bop_name = "buf_ops_bio", 891573Srgrimes .bop_write = bufwrite, 901573Srgrimes .bop_strategy = bufstrategy, 911573Srgrimes .bop_sync = bufsync, 921573Srgrimes .bop_bdflush = bufbdflush, 931573Srgrimes}; 941573Srgrimes 95132019Stjr/* 961573Srgrimes * XXX buf is global because kern_shutdown.c and ffs_checkoverlap has 971573Srgrimes * carnal knowledge of buffers. This knowledge should be moved to vfs_bio.c. 981573Srgrimes */ 991573Srgrimesstruct buf *buf; /* buffer header pool */ 1001573Srgrimescaddr_t unmapped_buf; 1011573Srgrimes 1021573Srgrimesstatic struct proc *bufdaemonproc; 1031573Srgrimes 10492905Sobrienstatic int inmem(struct vnode *vp, daddr_t blkno); 10592905Sobrienstatic void vm_hold_free_pages(struct buf *bp, int newbsize); 106167222Sdelphijstatic void vm_hold_load_pages(struct buf *bp, vm_offset_t from, 10792905Sobrien vm_offset_t to); 10892905Sobrienstatic void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m); 109132019Stjrstatic void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, 110167222Sdelphij vm_page_t m); 111132019Stjrstatic void vfs_clean_pages_dirty_buf(struct buf *bp); 112132019Stjrstatic void vfs_setdirty_locked_object(struct buf *bp); 113132019Stjrstatic void vfs_vmio_release(struct buf *bp); 114132019Stjrstatic int vfs_bio_clcheck(struct vnode *vp, int size, 115132019Stjr daddr_t lblkno, daddr_t blkno); 116132019Stjrstatic int buf_flush(int); 117132019Stjrstatic int flushbufqueues(int, int); 118132019Stjrstatic void buf_daemon(void); 1191573Srgrimesstatic void bremfreel(struct buf *bp); 12092905Sobrienstatic __inline void bd_wakeup(void); 1211573Srgrimes#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 1221573Srgrimes defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 12392905Sobrienstatic int sysctl_bufspace(SYSCTL_HANDLER_ARGS); 1241573Srgrimes#endif 1251573Srgrimes 12692905Sobrienint vmiodirenable = TRUE; 1271573SrgrimesSYSCTL_INT(_vfs, OID_AUTO, vmiodirenable, CTLFLAG_RW, &vmiodirenable, 0, 1281573Srgrimes "Use the VM system for directory writes"); 1291573Srgrimeslong runningbufspace; 1301573SrgrimesSYSCTL_LONG(_vfs, OID_AUTO, runningbufspace, CTLFLAG_RD, &runningbufspace, 0, 1311573Srgrimes "Amount of presently outstanding async buffer io"); 1321573Srgrimesstatic long bufspace; 1331573Srgrimes#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 1341573Srgrimes defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 1351573SrgrimesSYSCTL_PROC(_vfs, OID_AUTO, bufspace, CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RD, 1361573Srgrimes &bufspace, 0, sysctl_bufspace, "L", "Virtual memory used for buffers"); 1371573Srgrimes#else 1381573SrgrimesSYSCTL_LONG(_vfs, OID_AUTO, bufspace, CTLFLAG_RD, &bufspace, 0, 1391573Srgrimes "Virtual memory used for buffers"); 1401573Srgrimes#endif 1411573Srgrimesstatic long unmapped_bufspace; 1421573SrgrimesSYSCTL_LONG(_vfs, OID_AUTO, unmapped_bufspace, CTLFLAG_RD, 1431573Srgrimes &unmapped_bufspace, 0, 1441573Srgrimes "Amount of unmapped buffers, inclusive in the bufspace"); 1451573Srgrimesstatic long maxbufspace; 14692889SobrienSYSCTL_LONG(_vfs, OID_AUTO, maxbufspace, CTLFLAG_RD, &maxbufspace, 0, 1471573Srgrimes "Maximum allowed value of bufspace (including buf_daemon)"); 1481573Srgrimesstatic long bufmallocspace; 1491573SrgrimesSYSCTL_LONG(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0, 1501573Srgrimes "Amount of malloced memory for buffers"); 15192889Sobrienstatic long maxbufmallocspace; 1521573SrgrimesSYSCTL_LONG(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace, 0, 1531573Srgrimes "Maximum amount of malloced memory for buffers"); 1541573Srgrimesstatic long lobufspace; 1551573SrgrimesSYSCTL_LONG(_vfs, OID_AUTO, lobufspace, CTLFLAG_RD, &lobufspace, 0, 1561573Srgrimes "Minimum amount of buffers we want to have"); 15792889Sobrienlong hibufspace; 15892889SobrienSYSCTL_LONG(_vfs, OID_AUTO, hibufspace, CTLFLAG_RD, &hibufspace, 0, 1591573Srgrimes "Maximum allowed value of bufspace (excluding buf_daemon)"); 16092889Sobrienstatic int bufreusecnt; 16192889SobrienSYSCTL_INT(_vfs, OID_AUTO, bufreusecnt, CTLFLAG_RW, &bufreusecnt, 0, 16292889Sobrien "Number of times we have reused a buffer"); 16392889Sobrienstatic int buffreekvacnt; 1641573SrgrimesSYSCTL_INT(_vfs, OID_AUTO, buffreekvacnt, CTLFLAG_RW, &buffreekvacnt, 0, 1651573Srgrimes "Number of times we have freed the KVA space from some buffer"); 16662232Sdcsstatic int bufdefragcnt; 16792889SobrienSYSCTL_INT(_vfs, OID_AUTO, bufdefragcnt, CTLFLAG_RW, &bufdefragcnt, 0, 16862232Sdcs "Number of times we have had to repeat buffer allocation to defragment"); 16992889Sobrienstatic long lorunningspace; 17092889SobrienSYSCTL_LONG(_vfs, OID_AUTO, lorunningspace, CTLFLAG_RW, &lorunningspace, 0, 17192889Sobrien "Minimum preferred space used for in-progress I/O"); 17292889Sobrienstatic long hirunningspace; 1731573SrgrimesSYSCTL_LONG(_vfs, OID_AUTO, hirunningspace, CTLFLAG_RW, &hirunningspace, 0, 1741573Srgrimes "Maximum amount of space to use for in-progress I/O"); 1751573Srgrimesint dirtybufferflushes; 1761573SrgrimesSYSCTL_INT(_vfs, OID_AUTO, dirtybufferflushes, CTLFLAG_RW, &dirtybufferflushes, 1771573Srgrimes 0, "Number of bdwrite to bawrite conversions to limit dirty buffers"); 1781573Srgrimesint bdwriteskip; 1791573SrgrimesSYSCTL_INT(_vfs, OID_AUTO, bdwriteskip, CTLFLAG_RW, &bdwriteskip, 1801573Srgrimes 0, "Number of buffers supplied to bdwrite with snapshot deadlock risk"); 1811573Srgrimesint altbufferflushes; 1821573SrgrimesSYSCTL_INT(_vfs, OID_AUTO, altbufferflushes, CTLFLAG_RW, &altbufferflushes, 1831573Srgrimes 0, "Number of fsync flushes to limit dirty buffers"); 1841573Srgrimesstatic int recursiveflushes; 1851573SrgrimesSYSCTL_INT(_vfs, OID_AUTO, recursiveflushes, CTLFLAG_RW, &recursiveflushes, 1861573Srgrimes 0, "Number of flushes skipped due to being recursive"); 1871573Srgrimesstatic int numdirtybuffers; 1881573SrgrimesSYSCTL_INT(_vfs, OID_AUTO, numdirtybuffers, CTLFLAG_RD, &numdirtybuffers, 0, 18962391Sdcs "Number of buffers that are dirty (has unwritten changes) at the moment"); 19062232Sdcsstatic int lodirtybuffers; 19162232SdcsSYSCTL_INT(_vfs, OID_AUTO, lodirtybuffers, CTLFLAG_RW, &lodirtybuffers, 0, 19262232Sdcs "How many buffers we want to have free before bufdaemon can sleep"); 19362232Sdcsstatic int hidirtybuffers; 19462232SdcsSYSCTL_INT(_vfs, OID_AUTO, hidirtybuffers, CTLFLAG_RW, &hidirtybuffers, 0, 19562754Sdcs "When the number of dirty buffers is considered severe"); 19662232Sdcsint dirtybufthresh; 197111010SnectarSYSCTL_INT(_vfs, OID_AUTO, dirtybufthresh, CTLFLAG_RW, &dirtybufthresh, 198111010Snectar 0, "Number of bdwrite to bawrite conversions to clear dirty buffers"); 19962232Sdcsstatic int numfreebuffers; 20062754SdcsSYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0, 20162232Sdcs "Number of free buffers"); 20262232Sdcsstatic int lofreebuffers; 20362232SdcsSYSCTL_INT(_vfs, OID_AUTO, lofreebuffers, CTLFLAG_RW, &lofreebuffers, 0, 20462232Sdcs "XXX Unused"); 20562232Sdcsstatic int hifreebuffers; 20662232SdcsSYSCTL_INT(_vfs, OID_AUTO, hifreebuffers, CTLFLAG_RW, &hifreebuffers, 0, 20762754Sdcs "XXX Complicatedly unused"); 20862232Sdcsstatic int getnewbufcalls; 20962754SdcsSYSCTL_INT(_vfs, OID_AUTO, getnewbufcalls, CTLFLAG_RW, &getnewbufcalls, 0, 21062232Sdcs "Number of calls to getnewbuf"); 21162232Sdcsstatic int getnewbufrestarts; 21262232SdcsSYSCTL_INT(_vfs, OID_AUTO, getnewbufrestarts, CTLFLAG_RW, &getnewbufrestarts, 0, 21362232Sdcs "Number of times getnewbuf has had to restart a buffer aquisition"); 214111010Snectarstatic int mappingrestarts; 21562754SdcsSYSCTL_INT(_vfs, OID_AUTO, mappingrestarts, CTLFLAG_RW, &mappingrestarts, 0, 21662754Sdcs "Number of times getblk has had to restart a buffer mapping for " 21762232Sdcs "unmapped buffer"); 21862391Sdcsstatic int flushbufqtarget = 100; 21962232SdcsSYSCTL_INT(_vfs, OID_AUTO, flushbufqtarget, CTLFLAG_RW, &flushbufqtarget, 0, 22062232Sdcs "Amount of work to do in flushbufqueues when helping bufdaemon"); 22162232Sdcsstatic long notbufdflushes; 22262232SdcsSYSCTL_LONG(_vfs, OID_AUTO, notbufdflushes, CTLFLAG_RD, ¬bufdflushes, 0, 22362232Sdcs "Number of dirty buffer flushes done by the bufdaemon helpers"); 22462232Sdcsstatic long barrierwrites; 22562232SdcsSYSCTL_LONG(_vfs, OID_AUTO, barrierwrites, CTLFLAG_RW, &barrierwrites, 0, 22662232Sdcs "Number of barrier writes"); 22762232SdcsSYSCTL_INT(_vfs, OID_AUTO, unmapped_buf_allowed, CTLFLAG_RD, 22862232Sdcs &unmapped_buf_allowed, 0, 2291573Srgrimes "Permit the use of the unmapped i/o"); 2301573Srgrimes 2311573Srgrimes/* 2321573Srgrimes * Lock for the non-dirty bufqueues 2331573Srgrimes */ 2341573Srgrimesstatic struct mtx_padalign bqclean; 2351573Srgrimes 2361573Srgrimes/* 2371573Srgrimes * Lock for the dirty queue. 2381573Srgrimes */ 2391573Srgrimesstatic struct mtx_padalign bqdirty; 2401573Srgrimes 2411573Srgrimes/* 2421573Srgrimes * This lock synchronizes access to bd_request. 2431573Srgrimes */ 2441573Srgrimesstatic struct mtx_padalign bdlock; 245132019Stjr 2461573Srgrimes/* 24762391Sdcs * This lock protects the runningbufreq and synchronizes runningbufwakeup and 24862391Sdcs * waitrunningbufspace(). 24962854Sdcs */ 25062391Sdcsstatic struct mtx_padalign rbreqlock; 2511573Srgrimes 2521573Srgrimes/* 2531573Srgrimes * Lock that protects needsbuffer and the sleeps/wakeups surrounding it. 2541573Srgrimes */ 255139437Sddsstatic struct mtx_padalign nblock; 256139437Sdds 257139437Sdds/* 258139437Sdds * Lock that protects bdirtywait. 2591573Srgrimes */ 2601573Srgrimesstatic struct mtx_padalign bdirtylock; 2611573Srgrimes 2621573Srgrimes/* 2631573Srgrimes * Wakeup point for bufdaemon, as well as indicator of whether it is already 2641573Srgrimes * active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it 2651573Srgrimes * is idling. 2661573Srgrimes */ 2671573Srgrimesstatic int bd_request; 2681573Srgrimes 2691573Srgrimes/* 2701573Srgrimes * Request for the buf daemon to write more buffers than is indicated by 2711573Srgrimes * lodirtybuf. This may be necessary to push out excess dependencies or 2721573Srgrimes * defragment the address space where a simple count of the number of dirty 273132019Stjr * buffers is insufficient to characterize the demand for flushing them. 274132019Stjr */ 2751573Srgrimesstatic int bd_speedupreq; 2761573Srgrimes 2771573Srgrimes/* 2781573Srgrimes * bogus page -- for I/O to/from partially complete buffers 2791573Srgrimes * this is a temporary solution to the problem, but it is not 2801573Srgrimes * really that bad. it would be better to split the buffer 2811573Srgrimes * for input in the case of buffers partially already in memory, 2821573Srgrimes * but the code is intricate enough already. 2831573Srgrimes */ 2841573Srgrimesvm_page_t bogus_page; 2851573Srgrimes 2861573Srgrimes/* 2871573Srgrimes * Synchronization (sleep/wakeup) variable for active buffer space requests. 2881573Srgrimes * Set when wait starts, cleared prior to wakeup(). 2891573Srgrimes * Used in runningbufwakeup() and waitrunningbufspace(). 2901573Srgrimes */ 2911573Srgrimesstatic int runningbufreq; 2921573Srgrimes 2931573Srgrimes/* 2941573Srgrimes * Synchronization (sleep/wakeup) variable for buffer requests. 2951573Srgrimes * Can contain the VFS_BIO_NEED flags defined below; setting/clearing is done 2961573Srgrimes * by and/or. 2971573Srgrimes * Used in numdirtywakeup(), bufspacewakeup(), bufcountadd(), bwillwrite(), 2981573Srgrimes * getnewbuf(), and getblk(). 2991573Srgrimes */ 3001573Srgrimesstatic int needsbuffer; 3011573Srgrimes 302167222Sdelphij/* 3031573Srgrimes * Synchronization for bwillwrite() waiters. 3041573Srgrimes */ 3051573Srgrimesstatic int bdirtywait; 3061573Srgrimes 3071573Srgrimes/* 3081573Srgrimes * Definitions for the buffer free lists. 3091573Srgrimes */ 3101573Srgrimes#define BUFFER_QUEUES 5 /* number of free buffer queues */ 3111573Srgrimes 3121573Srgrimes#define QUEUE_NONE 0 /* on no queue */ 3131573Srgrimes#define QUEUE_CLEAN 1 /* non-B_DELWRI buffers */ 3141573Srgrimes#define QUEUE_DIRTY 2 /* B_DELWRI buffers */ 3151573Srgrimes#define QUEUE_EMPTYKVA 3 /* empty buffer headers w/KVA assignment */ 3161573Srgrimes#define QUEUE_EMPTY 4 /* empty buffer headers */ 3171573Srgrimes#define QUEUE_SENTINEL 1024 /* not an queue index, but mark for sentinel */ 3181573Srgrimes 3191573Srgrimes/* Queues for free buffers with various properties */ 3201573Srgrimesstatic TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES] = { { 0 } }; 3211573Srgrimes#ifdef INVARIANTS 3221573Srgrimesstatic int bq_len[BUFFER_QUEUES]; 3231573Srgrimes#endif 3241573Srgrimes 325167222Sdelphij/* 3261573Srgrimes * Single global constant for BUF_WMESG, to avoid getting multiple references. 3271573Srgrimes * buf_wmesg is referred from macros. 3281573Srgrimes */ 3291573Srgrimesconst char *buf_wmesg = BUF_WMESG; 3301573Srgrimes 3311573Srgrimes#define VFS_BIO_NEED_ANY 0x01 /* any freeable buffer */ 3321573Srgrimes#define VFS_BIO_NEED_FREE 0x04 /* wait for free bufs, hi hysteresis */ 333132019Stjr#define VFS_BIO_NEED_BUFSPACE 0x08 /* wait for buf space, lo hysteresis */ 334132019Stjr 335137959Stjr#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 3361573Srgrimes defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 3371573Srgrimesstatic int 3381573Srgrimessysctl_bufspace(SYSCTL_HANDLER_ARGS) 3391573Srgrimes{ 3401573Srgrimes long lvalue; 3411573Srgrimes int ivalue; 3421573Srgrimes 3431573Srgrimes if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long)) 3441573Srgrimes return (sysctl_handle_long(oidp, arg1, arg2, req)); 3451573Srgrimes lvalue = *(long *)arg1; 3461573Srgrimes if (lvalue > INT_MAX) 3471573Srgrimes /* On overflow, still write out a long to trigger ENOMEM. */ 3481573Srgrimes return (sysctl_handle_long(oidp, &lvalue, 0, req)); 3491573Srgrimes ivalue = lvalue; 3501573Srgrimes return (sysctl_handle_int(oidp, &ivalue, 0, req)); 3511573Srgrimes} 3521573Srgrimes#endif 3531573Srgrimes 3541573Srgrimes#ifdef DIRECTIO 3551573Srgrimesextern void ffs_rawread_setup(void); 3561573Srgrimes#endif /* DIRECTIO */ 3571573Srgrimes 3581573Srgrimes/* 3591573Srgrimes * bqlock: 3601573Srgrimes * 3611573Srgrimes * Return the appropriate queue lock based on the index. 3621573Srgrimes */ 3631573Srgrimesstatic inline struct mtx * 3641573Srgrimesbqlock(int qindex) 36592889Sobrien{ 3661573Srgrimes 3671573Srgrimes if (qindex == QUEUE_DIRTY) 3681573Srgrimes return (struct mtx *)(&bqdirty); 3691573Srgrimes return (struct mtx *)(&bqclean); 37092889Sobrien} 3711573Srgrimes 3721573Srgrimes/* 3731573Srgrimes * bdirtywakeup: 3741573Srgrimes * 3751573Srgrimes * Wakeup any bwillwrite() waiters. 37692889Sobrien */ 37792889Sobrienstatic void 37892889Sobrienbdirtywakeup(void) 37992889Sobrien{ 38092889Sobrien mtx_lock(&bdirtylock); 38192889Sobrien if (bdirtywait) { 38292889Sobrien bdirtywait = 0; 38392889Sobrien wakeup(&bdirtywait); 38492889Sobrien } 38592889Sobrien mtx_unlock(&bdirtylock); 38692889Sobrien} 38792889Sobrien 38892889Sobrien/* 3891573Srgrimes * bdirtysub: 3901573Srgrimes * 3911573Srgrimes * Decrement the numdirtybuffers count by one and wakeup any 3921573Srgrimes * threads blocked in bwillwrite(). 3931573Srgrimes */ 3941573Srgrimesstatic void 3951573Srgrimesbdirtysub(void) 3961573Srgrimes{ 3971573Srgrimes 3981573Srgrimes if (atomic_fetchadd_int(&numdirtybuffers, -1) == 3991573Srgrimes (lodirtybuffers + hidirtybuffers) / 2) 4001573Srgrimes bdirtywakeup(); 4011573Srgrimes} 4021573Srgrimes 4031573Srgrimes/* 4041573Srgrimes * bdirtyadd: 4051573Srgrimes * 4061573Srgrimes * Increment the numdirtybuffers count by one and wakeup the buf 4071573Srgrimes * daemon if needed. 4081573Srgrimes */ 4091573Srgrimesstatic void 4101573Srgrimesbdirtyadd(void) 4111573Srgrimes{ 4121573Srgrimes 413132019Stjr /* 4141573Srgrimes * Only do the wakeup once as we cross the boundary. The 4151573Srgrimes * buf daemon will keep running until the condition clears. 4161573Srgrimes */ 4171573Srgrimes if (atomic_fetchadd_int(&numdirtybuffers, 1) == 4181573Srgrimes (lodirtybuffers + hidirtybuffers) / 2) 4191573Srgrimes bd_wakeup(); 4201573Srgrimes} 4211573Srgrimes 422132019Stjr/* 4231573Srgrimes * bufspacewakeup: 4241573Srgrimes * 4251573Srgrimes * Called when buffer space is potentially available for recovery. 4261573Srgrimes * getnewbuf() will block on this flag when it is unable to free 4271573Srgrimes * sufficient buffer space. Buffer space becomes recoverable when 4281573Srgrimes * bp's get placed back in the queues. 4291573Srgrimes */ 4301573Srgrimes 4311573Srgrimesstatic __inline void 4321573Srgrimesbufspacewakeup(void) 4331573Srgrimes{ 4341573Srgrimes 4351573Srgrimes /* 4361573Srgrimes * If someone is waiting for BUF space, wake them up. Even 4371573Srgrimes * though we haven't freed the kva space yet, the waiting 4381573Srgrimes * process will be able to now. 4391573Srgrimes */ 4401573Srgrimes mtx_lock(&nblock); 4411573Srgrimes if (needsbuffer & VFS_BIO_NEED_BUFSPACE) { 4421573Srgrimes needsbuffer &= ~VFS_BIO_NEED_BUFSPACE; 4431573Srgrimes wakeup(&needsbuffer); 4441573Srgrimes } 4451573Srgrimes mtx_unlock(&nblock); 4461573Srgrimes} 4471573Srgrimes 4481573Srgrimes/* 4491573Srgrimes * runningwakeup: 4501573Srgrimes * 4511573Srgrimes * Wake up processes that are waiting on asynchronous writes to fall 4521573Srgrimes * below lorunningspace. 4531573Srgrimes */ 4541573Srgrimesstatic void 4551573Srgrimesrunningwakeup(void) 4561573Srgrimes{ 4571573Srgrimes 4581573Srgrimes mtx_lock(&rbreqlock); 4591573Srgrimes if (runningbufreq) { 4601573Srgrimes runningbufreq = 0; 4611573Srgrimes wakeup(&runningbufreq); 4621573Srgrimes } 4631573Srgrimes mtx_unlock(&rbreqlock); 4641573Srgrimes} 4651573Srgrimes 4661573Srgrimes/* 4671573Srgrimes * runningbufwakeup: 4681573Srgrimes * 4691573Srgrimes * Decrement the outstanding write count according. 4701573Srgrimes */ 4711573Srgrimesvoid 4721573Srgrimesrunningbufwakeup(struct buf *bp) 4731573Srgrimes{ 4741573Srgrimes long space, bspace; 4751573Srgrimes 4761573Srgrimes bspace = bp->b_runningbufspace; 4771573Srgrimes if (bspace == 0) 4781573Srgrimes return; 4791573Srgrimes space = atomic_fetchadd_long(&runningbufspace, -bspace); 4801573Srgrimes KASSERT(space >= bspace, ("runningbufspace underflow %ld %ld", 4811573Srgrimes space, bspace)); 4821573Srgrimes bp->b_runningbufspace = 0; 4831573Srgrimes /* 4841573Srgrimes * Only acquire the lock and wakeup on the transition from exceeding 4851573Srgrimes * the threshold to falling below it. 4861573Srgrimes */ 4871573Srgrimes if (space < lorunningspace) 4881573Srgrimes return; 4891573Srgrimes if (space - bspace > lorunningspace) 4901573Srgrimes return; 4911573Srgrimes runningwakeup(); 4921573Srgrimes} 4931573Srgrimes 4941573Srgrimes/* 4951573Srgrimes * bufcountadd: 4961573Srgrimes * 4971573Srgrimes * Called when a buffer has been added to one of the free queues to 4981573Srgrimes * account for the buffer and to wakeup anyone waiting for free buffers. 4991573Srgrimes * This typically occurs when large amounts of metadata are being handled 5001573Srgrimes * by the buffer cache ( else buffer space runs out first, usually ). 5011573Srgrimes */ 5021573Srgrimesstatic __inline void 5031573Srgrimesbufcountadd(struct buf *bp) 5041573Srgrimes{ 5051573Srgrimes int old; 5061573Srgrimes 5071573Srgrimes KASSERT((bp->b_flags & B_INFREECNT) == 0, 5081573Srgrimes ("buf %p already counted as free", bp)); 5091573Srgrimes bp->b_flags |= B_INFREECNT; 5101573Srgrimes old = atomic_fetchadd_int(&numfreebuffers, 1); 5111573Srgrimes KASSERT(old >= 0 && old < nbuf, 5121573Srgrimes ("numfreebuffers climbed to %d", old + 1)); 5131573Srgrimes mtx_lock(&nblock); 5141573Srgrimes if (needsbuffer) { 5151573Srgrimes needsbuffer &= ~VFS_BIO_NEED_ANY; 5161573Srgrimes if (numfreebuffers >= hifreebuffers) 5171573Srgrimes needsbuffer &= ~VFS_BIO_NEED_FREE; 5181573Srgrimes wakeup(&needsbuffer); 5191573Srgrimes } 5201573Srgrimes mtx_unlock(&nblock); 5211573Srgrimes} 5221573Srgrimes 5231573Srgrimes/* 5241573Srgrimes * bufcountsub: 5251573Srgrimes * 5261573Srgrimes * Decrement the numfreebuffers count as needed. 5271573Srgrimes */ 5281573Srgrimesstatic void 5291573Srgrimesbufcountsub(struct buf *bp) 5301573Srgrimes{ 5311573Srgrimes int old; 5321573Srgrimes 5331573Srgrimes /* 5341573Srgrimes * Fixup numfreebuffers count. If the buffer is invalid or not 5351573Srgrimes * delayed-write, the buffer was free and we must decrement 5361573Srgrimes * numfreebuffers. 5371573Srgrimes */ 5381573Srgrimes if ((bp->b_flags & B_INVAL) || (bp->b_flags & B_DELWRI) == 0) { 5391573Srgrimes KASSERT((bp->b_flags & B_INFREECNT) != 0, 5401573Srgrimes ("buf %p not counted in numfreebuffers", bp)); 5411573Srgrimes bp->b_flags &= ~B_INFREECNT; 5421573Srgrimes old = atomic_fetchadd_int(&numfreebuffers, -1); 5431573Srgrimes KASSERT(old > 0, ("numfreebuffers dropped to %d", old - 1)); 5441573Srgrimes } 5451573Srgrimes} 5461573Srgrimes 5471573Srgrimes/* 5481573Srgrimes * waitrunningbufspace() 5491573Srgrimes * 5501573Srgrimes * runningbufspace is a measure of the amount of I/O currently 5511573Srgrimes * running. This routine is used in async-write situations to 5521573Srgrimes * prevent creating huge backups of pending writes to a device. 55392889Sobrien * Only asynchronous writes are governed by this function. 5541573Srgrimes * 5551573Srgrimes * This does NOT turn an async write into a sync write. It waits 5561573Srgrimes * for earlier writes to complete and generally returns before the 557167222Sdelphij * caller's write has reached the device. 55892889Sobrien */ 5591573Srgrimesvoid 5601573Srgrimeswaitrunningbufspace(void) 5611573Srgrimes{ 5621573Srgrimes 5631573Srgrimes mtx_lock(&rbreqlock); 564167222Sdelphij while (runningbufspace > hirunningspace) { 5651573Srgrimes runningbufreq = 1; 56692889Sobrien msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0); 56792889Sobrien } 56892889Sobrien mtx_unlock(&rbreqlock); 56992889Sobrien} 57092889Sobrien 57192889Sobrien 57292889Sobrien/* 57392889Sobrien * vfs_buf_test_cache: 57492889Sobrien * 57592889Sobrien * Called when a buffer is extended. This function clears the B_CACHE 57692889Sobrien * bit if the newly extended portion of the buffer does not contain 57792889Sobrien * valid data. 578132019Stjr */ 5791573Srgrimesstatic __inline 5801573Srgrimesvoid 5811573Srgrimesvfs_buf_test_cache(struct buf *bp, 5821573Srgrimes vm_ooffset_t foff, vm_offset_t off, vm_offset_t size, 5831573Srgrimes vm_page_t m) 5841573Srgrimes{ 5851573Srgrimes 5861573Srgrimes VM_OBJECT_ASSERT_LOCKED(m->object); 5871573Srgrimes if (bp->b_flags & B_CACHE) { 588132019Stjr int base = (foff + off) & PAGE_MASK; 5891573Srgrimes if (vm_page_is_valid(m, base, size) == 0) 590132019Stjr bp->b_flags &= ~B_CACHE; 591132019Stjr } 592132019Stjr} 5931573Srgrimes 5941573Srgrimes/* Wake up the buffer daemon if necessary */ 5951573Srgrimesstatic __inline void 5961573Srgrimesbd_wakeup(void) 597132019Stjr{ 598132019Stjr 599132019Stjr mtx_lock(&bdlock); 6001573Srgrimes if (bd_request == 0) { 6011573Srgrimes bd_request = 1; 602132019Stjr wakeup(&bd_request); 603132019Stjr } 6041573Srgrimes mtx_unlock(&bdlock); 605132019Stjr} 606132019Stjr 6071573Srgrimes/* 6081573Srgrimes * bd_speedup - speedup the buffer cache flushing code 6091573Srgrimes */ 6101573Srgrimesvoid 6111573Srgrimesbd_speedup(void) 6121573Srgrimes{ 6131573Srgrimes int needwake; 6141573Srgrimes 6151573Srgrimes mtx_lock(&bdlock); 6161573Srgrimes needwake = 0; 6171573Srgrimes if (bd_speedupreq == 0 || bd_request == 0) 6181573Srgrimes needwake = 1; 6191573Srgrimes bd_speedupreq = 1; 6201573Srgrimes bd_request = 1; 6211573Srgrimes if (needwake) 6221573Srgrimes wakeup(&bd_request); 6231573Srgrimes mtx_unlock(&bdlock); 6241573Srgrimes} 6251573Srgrimes 6261573Srgrimes#ifdef __i386__ 6271573Srgrimes#define TRANSIENT_DENOM 5 6281573Srgrimes#else 6291573Srgrimes#define TRANSIENT_DENOM 10 6301573Srgrimes#endif 6311573Srgrimes 6321573Srgrimes/* 6331573Srgrimes * Calculating buffer cache scaling values and reserve space for buffer 6341573Srgrimes * headers. This is called during low level kernel initialization and 6351573Srgrimes * may be called more then once. We CANNOT write to the memory area 6361573Srgrimes * being reserved at this time. 6371573Srgrimes */ 6381573Srgrimescaddr_t 6391573Srgrimeskern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est) 6401573Srgrimes{ 6411573Srgrimes int tuned_nbuf; 6421573Srgrimes long maxbuf, maxbuf_sz, buf_sz, biotmap_sz; 6431573Srgrimes 6441573Srgrimes /* 6451573Srgrimes * physmem_est is in pages. Convert it to kilobytes (assumes 6461573Srgrimes * PAGE_SIZE is >= 1K) 6471573Srgrimes */ 6481573Srgrimes physmem_est = physmem_est * (PAGE_SIZE / 1024); 6491573Srgrimes 6501573Srgrimes /* 6511573Srgrimes * The nominal buffer size (and minimum KVA allocation) is BKVASIZE. 6521573Srgrimes * For the first 64MB of ram nominally allocate sufficient buffers to 6531573Srgrimes * cover 1/4 of our ram. Beyond the first 64MB allocate additional 6541573Srgrimes * buffers to cover 1/10 of our ram over 64MB. When auto-sizing 6551573Srgrimes * the buffer cache we limit the eventual kva reservation to 6561573Srgrimes * maxbcache bytes. 6571573Srgrimes * 6581573Srgrimes * factor represents the 1/4 x ram conversion. 6591573Srgrimes */ 6601573Srgrimes if (nbuf == 0) { 6611573Srgrimes int factor = 4 * BKVASIZE / 1024; 6621573Srgrimes 6631573Srgrimes nbuf = 50; 6641573Srgrimes if (physmem_est > 4096) 6651573Srgrimes nbuf += min((physmem_est - 4096) / factor, 6661573Srgrimes 65536 / factor); 6671573Srgrimes if (physmem_est > 65536) 6681573Srgrimes nbuf += min((physmem_est - 65536) * 2 / (factor * 5), 6691573Srgrimes 32 * 1024 * 1024 / (factor * 5)); 6701573Srgrimes 6711573Srgrimes if (maxbcache && nbuf > maxbcache / BKVASIZE) 6721573Srgrimes nbuf = maxbcache / BKVASIZE; 6731573Srgrimes tuned_nbuf = 1; 6741573Srgrimes } else 6751573Srgrimes tuned_nbuf = 0; 6761573Srgrimes 6771573Srgrimes /* XXX Avoid unsigned long overflows later on with maxbufspace. */ 6781573Srgrimes maxbuf = (LONG_MAX / 3) / BKVASIZE; 679167222Sdelphij if (nbuf > maxbuf) { 680167216Sdelphij if (!tuned_nbuf) 6811573Srgrimes printf("Warning: nbufs lowered from %d to %ld\n", nbuf, 6821573Srgrimes maxbuf); 6831573Srgrimes nbuf = maxbuf; 6841573Srgrimes } 6851573Srgrimes 6861573Srgrimes /* 6871573Srgrimes * Ideal allocation size for the transient bio submap if 10% 6881573Srgrimes * of the maximal space buffer map. This roughly corresponds 689167222Sdelphij * to the amount of the buffer mapped for typical UFS load. 6901573Srgrimes * 6911573Srgrimes * Clip the buffer map to reserve space for the transient 692167222Sdelphij * BIOs, if its extent is bigger than 90% (80% on i386) of the 6931573Srgrimes * maximum buffer map extent on the platform. 6941573Srgrimes * 695167222Sdelphij * The fall-back to the maxbuf in case of maxbcache unset, 6961573Srgrimes * allows to not trim the buffer KVA for the architectures 6971573Srgrimes * with ample KVA space. 6981573Srgrimes */ 6991573Srgrimes if (bio_transient_maxcnt == 0 && unmapped_buf_allowed) { 7001573Srgrimes maxbuf_sz = maxbcache != 0 ? maxbcache : maxbuf * BKVASIZE; 701167222Sdelphij buf_sz = (long)nbuf * BKVASIZE; 7021573Srgrimes if (buf_sz < maxbuf_sz / TRANSIENT_DENOM * 7031573Srgrimes (TRANSIENT_DENOM - 1)) { 7041573Srgrimes /* 705167222Sdelphij * There is more KVA than memory. Do not 7061573Srgrimes * adjust buffer map size, and assign the rest 7071573Srgrimes * of maxbuf to transient map. 708167222Sdelphij */ 7091573Srgrimes biotmap_sz = maxbuf_sz - buf_sz; 710167222Sdelphij } else { 7111573Srgrimes /* 7121573Srgrimes * Buffer map spans all KVA we could afford on 7131573Srgrimes * this platform. Give 10% (20% on i386) of 7141573Srgrimes * the buffer map to the transient bio map. 7151573Srgrimes */ 7161573Srgrimes biotmap_sz = buf_sz / TRANSIENT_DENOM; 7171573Srgrimes buf_sz -= biotmap_sz; 7181573Srgrimes } 719167222Sdelphij if (biotmap_sz / INT_MAX > MAXPHYS) 7201573Srgrimes bio_transient_maxcnt = INT_MAX; 7211573Srgrimes else 7221573Srgrimes bio_transient_maxcnt = biotmap_sz / MAXPHYS; 7231573Srgrimes /* 7241573Srgrimes * Artifically limit to 1024 simultaneous in-flight I/Os 7251573Srgrimes * using the transient mapping. 7261573Srgrimes */ 7271573Srgrimes if (bio_transient_maxcnt > 1024) 7281573Srgrimes bio_transient_maxcnt = 1024; 7291573Srgrimes if (tuned_nbuf) 7301573Srgrimes nbuf = buf_sz / BKVASIZE; 7311573Srgrimes } 7321573Srgrimes 7331573Srgrimes /* 7341573Srgrimes * swbufs are used as temporary holders for I/O, such as paging I/O. 7351573Srgrimes * We have no less then 16 and no more then 256. 7361573Srgrimes */ 7371573Srgrimes nswbuf = max(min(nbuf/4, 256), 16); 7381573Srgrimes#ifdef NSWBUF_MIN 7391573Srgrimes if (nswbuf < NSWBUF_MIN) 740167222Sdelphij nswbuf = NSWBUF_MIN; 7411573Srgrimes#endif 7421573Srgrimes#ifdef DIRECTIO 7431573Srgrimes ffs_rawread_setup(); 7441573Srgrimes#endif 7451573Srgrimes 7461573Srgrimes /* 7471573Srgrimes * Reserve space for the buffer cache buffers 7481573Srgrimes */ 7491573Srgrimes swbuf = (void *)v; 7501573Srgrimes v = (caddr_t)(swbuf + nswbuf); 751167222Sdelphij buf = (void *)v; 7521573Srgrimes v = (caddr_t)(buf + nbuf); 7531573Srgrimes 7541573Srgrimes return(v); 7551573Srgrimes} 7561573Srgrimes 7571573Srgrimes/* Initialize the buffer subsystem. Called before use of any buffers. */ 7581573Srgrimesvoid 7591573Srgrimesbufinit(void) 7601573Srgrimes{ 7611573Srgrimes struct buf *bp; 7621573Srgrimes int i; 7631573Srgrimes 7641573Srgrimes mtx_init(&bqclean, "bufq clean lock", NULL, MTX_DEF); 76511664Sphk mtx_init(&bqdirty, "bufq dirty lock", NULL, MTX_DEF); 7661573Srgrimes mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF); 7671573Srgrimes mtx_init(&nblock, "needsbuffer lock", NULL, MTX_DEF); 7681573Srgrimes mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF); 7691573Srgrimes mtx_init(&bdirtylock, "dirty buf lock", NULL, MTX_DEF); 77092889Sobrien 7711573Srgrimes /* next, make a null set of free lists */ 7721573Srgrimes for (i = 0; i < BUFFER_QUEUES; i++) 7731573Srgrimes TAILQ_INIT(&bufqueues[i]); 7741573Srgrimes 77592889Sobrien /* finally, initialize each buffer header and stick on empty q */ 7761573Srgrimes for (i = 0; i < nbuf; i++) { 7771573Srgrimes bp = &buf[i]; 7781573Srgrimes bzero(bp, sizeof *bp); 7791573Srgrimes bp->b_flags = B_INVAL | B_INFREECNT; 7801573Srgrimes bp->b_rcred = NOCRED; 78192889Sobrien bp->b_wcred = NOCRED; 78292889Sobrien bp->b_qindex = QUEUE_EMPTY; 78392889Sobrien bp->b_xflags = 0; 78492889Sobrien LIST_INIT(&bp->b_dep); 785132019Stjr BUF_LOCKINIT(bp); 786132019Stjr TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist); 787132019Stjr#ifdef INVARIANTS 78892889Sobrien bq_len[QUEUE_EMPTY]++; 78992889Sobrien#endif 790132019Stjr } 7911573Srgrimes 7921573Srgrimes /* 7931573Srgrimes * maxbufspace is the absolute maximum amount of buffer space we are 7941573Srgrimes * allowed to reserve in KVM and in real terms. The absolute maximum 7951573Srgrimes * is nominally used by buf_daemon. hibufspace is the nominal maximum 7961573Srgrimes * used by most other processes. The differential is required to 7971573Srgrimes * ensure that buf_daemon is able to run when other processes might 798132019Stjr * be blocked waiting for buffer space. 799132019Stjr * 800132019Stjr * maxbufspace is based on BKVASIZE. Allocating buffers larger then 801132019Stjr * this may result in KVM fragmentation which is not handled optimally 802132019Stjr * by the system. 803132019Stjr */ 804132019Stjr maxbufspace = (long)nbuf * BKVASIZE; 805132019Stjr hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - MAXBSIZE * 10); 806132019Stjr lobufspace = hibufspace - MAXBSIZE; 807132019Stjr 8081573Srgrimes /* 8091573Srgrimes * Note: The 16 MiB upper limit for hirunningspace was chosen 8101573Srgrimes * arbitrarily and may need further tuning. It corresponds to 811149180Stjr * 128 outstanding write IO requests (if IO size is 128 KiB), 812149180Stjr * which fits with many RAID controllers' tagged queuing limits. 813132019Stjr * The lower 1 MiB limit is the historical upper limit for 814149180Stjr * hirunningspace. 815149180Stjr */ 8161573Srgrimes hirunningspace = lmax(lmin(roundup(hibufspace / 64, MAXBSIZE), 8171573Srgrimes 16 * 1024 * 1024), 1024 * 1024); 8181573Srgrimes lorunningspace = roundup((hirunningspace * 2) / 3, MAXBSIZE); 8191573Srgrimes 8201573Srgrimes/* 8211573Srgrimes * Limit the amount of malloc memory since it is wired permanently into 8221573Srgrimes * the kernel space. Even though this is accounted for in the buffer 8231573Srgrimes * allocation, we don't want the malloced region to grow uncontrolled. 8241573Srgrimes * The malloc scheme improves memory utilization significantly on average 8251573Srgrimes * (small) directories. 8261573Srgrimes */ 8271573Srgrimes maxbufmallocspace = hibufspace / 20; 8281573Srgrimes 8291573Srgrimes/* 8301573Srgrimes * Reduce the chance of a deadlock occuring by limiting the number 8311573Srgrimes * of delayed-write dirty buffers we allow to stack up. 8321573Srgrimes */ 8331573Srgrimes hidirtybuffers = nbuf / 4 + 20; 8341573Srgrimes dirtybufthresh = hidirtybuffers * 9 / 10; 8351573Srgrimes numdirtybuffers = 0; 8361573Srgrimes/* 8371573Srgrimes * To support extreme low-memory systems, make sure hidirtybuffers cannot 8381573Srgrimes * eat up all available buffer space. This occurs when our minimum cannot 8391573Srgrimes * be met. We try to size hidirtybuffers to 3/4 our buffer space assuming 8401573Srgrimes * BKVASIZE'd buffers. 8411573Srgrimes */ 8421573Srgrimes while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) { 8431573Srgrimes hidirtybuffers >>= 1; 8441573Srgrimes } 8451573Srgrimes lodirtybuffers = hidirtybuffers / 2; 8461573Srgrimes 8471573Srgrimes/* 8481573Srgrimes * Try to keep the number of free buffers in the specified range, 8491573Srgrimes * and give special processes (e.g. like buf_daemon) access to an 8501573Srgrimes * emergency reserve. 8511573Srgrimes */ 8521573Srgrimes lofreebuffers = nbuf / 18 + 5; 853149180Stjr hifreebuffers = 2 * lofreebuffers; 8541573Srgrimes numfreebuffers = nbuf; 8551573Srgrimes 8561573Srgrimes bogus_page = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ | 8571573Srgrimes VM_ALLOC_NORMAL | VM_ALLOC_WIRED); 8581573Srgrimes unmapped_buf = (caddr_t)kva_alloc(MAXPHYS); 8591573Srgrimes} 8601573Srgrimes 8611573Srgrimes#ifdef INVARIANTS 8621573Srgrimesstatic inline void 863132019Stjrvfs_buf_check_mapped(struct buf *bp) 8641573Srgrimes{ 8651573Srgrimes 8661573Srgrimes KASSERT((bp->b_flags & B_UNMAPPED) == 0, 8671573Srgrimes ("mapped buf %p %x", bp, bp->b_flags)); 8681573Srgrimes KASSERT(bp->b_kvabase != unmapped_buf, 869137959Stjr ("mapped buf: b_kvabase was not updated %p", bp)); 8701573Srgrimes KASSERT(bp->b_data != unmapped_buf, 8711573Srgrimes ("mapped buf: b_data was not updated %p", bp)); 8721573Srgrimes} 8731573Srgrimes 8741573Srgrimesstatic inline void 8751573Srgrimesvfs_buf_check_unmapped(struct buf *bp) 87692889Sobrien{ 8771573Srgrimes 8781573Srgrimes KASSERT((bp->b_flags & B_UNMAPPED) == B_UNMAPPED, 8791573Srgrimes ("unmapped buf %p %x", bp, bp->b_flags)); 8801573Srgrimes KASSERT(bp->b_kvabase == unmapped_buf, 88192889Sobrien ("unmapped buf: corrupted b_kvabase %p", bp)); 8821573Srgrimes KASSERT(bp->b_data == unmapped_buf, 8831573Srgrimes ("unmapped buf: corrupted b_data %p", bp)); 8841573Srgrimes} 8851573Srgrimes 8861573Srgrimes#define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp) 88792889Sobrien#define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp) 88892889Sobrien#else 88992889Sobrien#define BUF_CHECK_MAPPED(bp) do {} while (0) 89092889Sobrien#define BUF_CHECK_UNMAPPED(bp) do {} while (0) 891132019Stjr#endif 892132019Stjr 893132019Stjrstatic void 89492889Sobrienbpmap_qenter(struct buf *bp) 89592889Sobrien{ 896132019Stjr 8971573Srgrimes BUF_CHECK_MAPPED(bp); 8981573Srgrimes 8991573Srgrimes /* 9001573Srgrimes * bp->b_data is relative to bp->b_offset, but 9011573Srgrimes * bp->b_offset may be offset into the first page. 9021573Srgrimes */ 9031573Srgrimes bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data); 904132019Stjr pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 905132019Stjr bp->b_data = (caddr_t)((vm_offset_t)bp->b_data | 906132019Stjr (vm_offset_t)(bp->b_offset & PAGE_MASK)); 907132019Stjr} 908132019Stjr 909132019Stjr/* 910132019Stjr * bfreekva() - free the kva allocation for a buffer. 911132019Stjr * 912132019Stjr * Since this call frees up buffer space, we call bufspacewakeup(). 913132019Stjr */ 9141573Srgrimesstatic void 9151573Srgrimesbfreekva(struct buf *bp) 9161573Srgrimes{ 917132019Stjr 918132019Stjr if (bp->b_kvasize == 0) 919132019Stjr return; 920132019Stjr 921149180Stjr atomic_add_int(&buffreekvacnt, 1); 9221573Srgrimes atomic_subtract_long(&bufspace, bp->b_kvasize); 9231573Srgrimes if ((bp->b_flags & B_UNMAPPED) == 0) { 9241573Srgrimes BUF_CHECK_MAPPED(bp); 9251573Srgrimes vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, 9261573Srgrimes bp->b_kvasize); 9271573Srgrimes } else { 9281573Srgrimes BUF_CHECK_UNMAPPED(bp); 9291573Srgrimes if ((bp->b_flags & B_KVAALLOC) != 0) { 9301573Srgrimes vmem_free(buffer_arena, (vm_offset_t)bp->b_kvaalloc, 9311573Srgrimes bp->b_kvasize); 9321573Srgrimes } 9331573Srgrimes atomic_subtract_long(&unmapped_bufspace, bp->b_kvasize); 9341573Srgrimes bp->b_flags &= ~(B_UNMAPPED | B_KVAALLOC); 9351573Srgrimes } 9361573Srgrimes bp->b_kvasize = 0; 9371573Srgrimes bufspacewakeup(); 9381573Srgrimes} 9391573Srgrimes 9401573Srgrimes/* 9411573Srgrimes * binsfree: 9421573Srgrimes * 9431573Srgrimes * Insert the buffer into the appropriate free list. 9441573Srgrimes */ 9451573Srgrimesstatic void 9461573Srgrimesbinsfree(struct buf *bp, int qindex) 9471573Srgrimes{ 9481573Srgrimes struct mtx *olock, *nlock; 9491573Srgrimes 9501573Srgrimes BUF_ASSERT_XLOCKED(bp); 9511573Srgrimes 9521573Srgrimes olock = bqlock(bp->b_qindex); 9531573Srgrimes nlock = bqlock(qindex); 9541573Srgrimes mtx_lock(olock); 9551573Srgrimes /* Handle delayed bremfree() processing. */ 9561573Srgrimes if (bp->b_flags & B_REMFREE) 9571573Srgrimes bremfreel(bp); 9581573Srgrimes 959149180Stjr if (bp->b_qindex != QUEUE_NONE) 9601573Srgrimes panic("binsfree: free buffer onto another queue???"); 9611573Srgrimes 9621573Srgrimes bp->b_qindex = qindex; 9631573Srgrimes if (olock != nlock) { 9641573Srgrimes mtx_unlock(olock); 9651573Srgrimes mtx_lock(nlock); 9661573Srgrimes } 9671573Srgrimes if (bp->b_flags & B_AGE) 9681573Srgrimes TAILQ_INSERT_HEAD(&bufqueues[bp->b_qindex], bp, b_freelist); 969132019Stjr else 9701573Srgrimes TAILQ_INSERT_TAIL(&bufqueues[bp->b_qindex], bp, b_freelist); 9711573Srgrimes#ifdef INVARIANTS 9721573Srgrimes bq_len[bp->b_qindex]++; 9731573Srgrimes#endif 9741573Srgrimes mtx_unlock(nlock); 9751573Srgrimes 9761573Srgrimes /* 9771573Srgrimes * Something we can maybe free or reuse. 97892889Sobrien */ 97992889Sobrien if (bp->b_bufsize && !(bp->b_flags & B_DELWRI)) 980132019Stjr bufspacewakeup(); 981132019Stjr 982132019Stjr if ((bp->b_flags & B_INVAL) || !(bp->b_flags & B_DELWRI)) 983132019Stjr bufcountadd(bp); 984132019Stjr} 985132019Stjr 986132019Stjr/* 987132019Stjr * bremfree: 9881573Srgrimes * 9891573Srgrimes * Mark the buffer for removal from the appropriate free list. 9901573Srgrimes * 99192889Sobrien */ 9921573Srgrimesvoid 9931573Srgrimesbremfree(struct buf *bp) 99492889Sobrien{ 995132019Stjr 99692889Sobrien CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 9971573Srgrimes KASSERT((bp->b_flags & B_REMFREE) == 0, 99892889Sobrien ("bremfree: buffer %p already marked for delayed removal.", bp)); 99992889Sobrien KASSERT(bp->b_qindex != QUEUE_NONE, 100092889Sobrien ("bremfree: buffer %p not on a queue.", bp)); 100192889Sobrien BUF_ASSERT_XLOCKED(bp); 100292889Sobrien 100392889Sobrien bp->b_flags |= B_REMFREE; 10041573Srgrimes bufcountsub(bp); 10051573Srgrimes} 10061573Srgrimes 10071573Srgrimes/* 10081573Srgrimes * bremfreef: 10091573Srgrimes * 10101573Srgrimes * Force an immediate removal from a free list. Used only in nfs when 10111573Srgrimes * it abuses the b_freelist pointer. 10121573Srgrimes */ 1013132019Stjrvoid 1014132019Stjrbremfreef(struct buf *bp) 10151573Srgrimes{ 10161573Srgrimes struct mtx *qlock; 10171573Srgrimes 10181573Srgrimes qlock = bqlock(bp->b_qindex); 10191573Srgrimes mtx_lock(qlock); 10201573Srgrimes bremfreel(bp); 10211573Srgrimes mtx_unlock(qlock); 10221573Srgrimes} 10231573Srgrimes 10241573Srgrimes/* 10251573Srgrimes * bremfreel: 10261573Srgrimes * 10271573Srgrimes * Removes a buffer from the free list, must be called with the 10281573Srgrimes * correct qlock held. 10291573Srgrimes */ 10301573Srgrimesstatic void 10311573Srgrimesbremfreel(struct buf *bp) 10321573Srgrimes{ 10331573Srgrimes 10341573Srgrimes CTR3(KTR_BUF, "bremfreel(%p) vp %p flags %X", 10351573Srgrimes bp, bp->b_vp, bp->b_flags); 10361573Srgrimes KASSERT(bp->b_qindex != QUEUE_NONE, 10371573Srgrimes ("bremfreel: buffer %p not on a queue.", bp)); 10381573Srgrimes BUF_ASSERT_XLOCKED(bp); 10391573Srgrimes mtx_assert(bqlock(bp->b_qindex), MA_OWNED); 10401573Srgrimes 10411573Srgrimes TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist); 10421573Srgrimes#ifdef INVARIANTS 10431573Srgrimes KASSERT(bq_len[bp->b_qindex] >= 1, ("queue %d underflow", 10441573Srgrimes bp->b_qindex)); 10451573Srgrimes bq_len[bp->b_qindex]--; 10461573Srgrimes#endif 10471573Srgrimes bp->b_qindex = QUEUE_NONE; 10481573Srgrimes /* 10491573Srgrimes * If this was a delayed bremfree() we only need to remove the buffer 10501573Srgrimes * from the queue and return the stats are already done. 10511573Srgrimes */ 10521573Srgrimes if (bp->b_flags & B_REMFREE) { 10531573Srgrimes bp->b_flags &= ~B_REMFREE; 10541573Srgrimes return; 10551573Srgrimes } 10561573Srgrimes bufcountsub(bp); 10571573Srgrimes} 10581573Srgrimes 10591573Srgrimes/* 10601573Srgrimes * Attempt to initiate asynchronous I/O on read-ahead blocks. We must 10611573Srgrimes * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set, 10621573Srgrimes * the buffer is valid and we do not have to do anything. 10631573Srgrimes */ 10641573Srgrimesvoid 10651573Srgrimesbreada(struct vnode * vp, daddr_t * rablkno, int * rabsize, 10661573Srgrimes int cnt, struct ucred * cred) 10671573Srgrimes{ 10681573Srgrimes struct buf *rabp; 10691573Srgrimes int i; 10701573Srgrimes 10711573Srgrimes for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 10721573Srgrimes if (inmem(vp, *rablkno)) 10731573Srgrimes continue; 10741573Srgrimes rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0); 10751573Srgrimes 10761573Srgrimes if ((rabp->b_flags & B_CACHE) == 0) { 10771573Srgrimes if (!TD_IS_IDLETHREAD(curthread)) 10781573Srgrimes curthread->td_ru.ru_inblock++; 10791573Srgrimes rabp->b_flags |= B_ASYNC; 10801573Srgrimes rabp->b_flags &= ~B_INVAL; 10811573Srgrimes rabp->b_ioflags &= ~BIO_ERROR; 10821573Srgrimes rabp->b_iocmd = BIO_READ; 10831573Srgrimes if (rabp->b_rcred == NOCRED && cred != NOCRED) 10841573Srgrimes rabp->b_rcred = crhold(cred); 10851573Srgrimes vfs_busy_pages(rabp, 0); 10861573Srgrimes BUF_KERNPROC(rabp); 10871573Srgrimes rabp->b_iooffset = dbtob(rabp->b_blkno); 10881573Srgrimes bstrategy(rabp); 10891573Srgrimes } else { 10901573Srgrimes brelse(rabp); 10911573Srgrimes } 10921573Srgrimes } 10931573Srgrimes} 10941573Srgrimes 10951573Srgrimes/* 10961573Srgrimes * Entry point for bread() and breadn() via #defines in sys/buf.h. 10971573Srgrimes * 10981573Srgrimes * Get a buffer with the specified data. Look in the cache first. We 10991573Srgrimes * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE 11001573Srgrimes * is set, the buffer is valid and we do not have to do anything, see 11011573Srgrimes * getblk(). Also starts asynchronous I/O on read-ahead blocks. 11021573Srgrimes */ 11031573Srgrimesint 11041573Srgrimesbreadn_flags(struct vnode *vp, daddr_t blkno, int size, daddr_t *rablkno, 11051573Srgrimes int *rabsize, int cnt, struct ucred *cred, int flags, struct buf **bpp) 11061573Srgrimes{ 11071573Srgrimes struct buf *bp; 11081573Srgrimes int rv = 0, readwait = 0; 11091573Srgrimes 11101573Srgrimes CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size); 11111573Srgrimes /* 11121573Srgrimes * Can only return NULL if GB_LOCK_NOWAIT flag is specified. 11131573Srgrimes */ 11141573Srgrimes *bpp = bp = getblk(vp, blkno, size, 0, 0, flags); 11151573Srgrimes if (bp == NULL) 11161573Srgrimes return (EBUSY); 11171573Srgrimes 11181573Srgrimes /* if not found in cache, do some I/O */ 111992889Sobrien if ((bp->b_flags & B_CACHE) == 0) { 112092889Sobrien if (!TD_IS_IDLETHREAD(curthread)) 112192889Sobrien curthread->td_ru.ru_inblock++; 11221573Srgrimes bp->b_iocmd = BIO_READ; 11231573Srgrimes bp->b_flags &= ~B_INVAL; 11241573Srgrimes bp->b_ioflags &= ~BIO_ERROR; 11251573Srgrimes if (bp->b_rcred == NOCRED && cred != NOCRED) 11261573Srgrimes bp->b_rcred = crhold(cred); 11271573Srgrimes vfs_busy_pages(bp, 0); 11281573Srgrimes bp->b_iooffset = dbtob(bp->b_blkno); 11291573Srgrimes bstrategy(bp); 11301573Srgrimes ++readwait; 11311573Srgrimes } 11321573Srgrimes 11331573Srgrimes breada(vp, rablkno, rabsize, cnt, cred); 11341573Srgrimes 11351573Srgrimes if (readwait) { 11361573Srgrimes rv = bufwait(bp); 11378870Srgrimes } 11381573Srgrimes return (rv); 11391573Srgrimes} 11401573Srgrimes 11411573Srgrimes/* 11421573Srgrimes * Write, release buffer on completion. (Done by iodone 11431573Srgrimes * if async). Do not bother writing anything if the buffer 11441573Srgrimes * is invalid. 11451573Srgrimes * 11461573Srgrimes * Note that we set B_CACHE here, indicating that buffer is 11471573Srgrimes * fully valid and thus cacheable. This is true even of NFS 11481573Srgrimes * now so we set it generally. This could be set either here 11491573Srgrimes * or in biodone() since the I/O is synchronous. We put it 11501573Srgrimes * here. 11511573Srgrimes */ 11521573Srgrimesint 11531573Srgrimesbufwrite(struct buf *bp) 11541573Srgrimes{ 11551573Srgrimes int oldflags; 11561573Srgrimes struct vnode *vp; 11571573Srgrimes long space; 11581573Srgrimes int vp_md; 11591573Srgrimes 11601573Srgrimes CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 11611573Srgrimes if (bp->b_flags & B_INVAL) { 11621573Srgrimes brelse(bp); 11631573Srgrimes return (0); 11641573Srgrimes } 11651573Srgrimes 11661573Srgrimes if (bp->b_flags & B_BARRIER) 11671573Srgrimes barrierwrites++; 11681573Srgrimes 11691573Srgrimes oldflags = bp->b_flags; 11701573Srgrimes 11711573Srgrimes BUF_ASSERT_HELD(bp); 11721573Srgrimes 11731573Srgrimes if (bp->b_pin_count > 0) 11741573Srgrimes bunpin_wait(bp); 11751573Srgrimes 11761573Srgrimes KASSERT(!(bp->b_vflags & BV_BKGRDINPROG), 11771573Srgrimes ("FFS background buffer should not get here %p", bp)); 11781573Srgrimes 11791573Srgrimes vp = bp->b_vp; 118017508Sache if (vp) 11811573Srgrimes vp_md = vp->v_vflag & VV_MD; 11821573Srgrimes else 11831573Srgrimes vp_md = 0; 11841573Srgrimes 11851573Srgrimes /* 11861573Srgrimes * Mark the buffer clean. Increment the bufobj write count 11871573Srgrimes * before bundirty() call, to prevent other thread from seeing 11881573Srgrimes * empty dirty list and zero counter for writes in progress, 11891573Srgrimes * falsely indicating that the bufobj is clean. 11901573Srgrimes */ 11911573Srgrimes bufobj_wref(bp->b_bufobj); 11921573Srgrimes bundirty(bp); 11931573Srgrimes 11941573Srgrimes bp->b_flags &= ~B_DONE; 11951573Srgrimes bp->b_ioflags &= ~BIO_ERROR; 11961573Srgrimes bp->b_flags |= B_CACHE; 11971573Srgrimes bp->b_iocmd = BIO_WRITE; 1198 1199 vfs_busy_pages(bp, 1); 1200 1201 /* 1202 * Normal bwrites pipeline writes 1203 */ 1204 bp->b_runningbufspace = bp->b_bufsize; 1205 space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace); 1206 1207 if (!TD_IS_IDLETHREAD(curthread)) 1208 curthread->td_ru.ru_oublock++; 1209 if (oldflags & B_ASYNC) 1210 BUF_KERNPROC(bp); 1211 bp->b_iooffset = dbtob(bp->b_blkno); 1212 bstrategy(bp); 1213 1214 if ((oldflags & B_ASYNC) == 0) { 1215 int rtval = bufwait(bp); 1216 brelse(bp); 1217 return (rtval); 1218 } else if (space > hirunningspace) { 1219 /* 1220 * don't allow the async write to saturate the I/O 1221 * system. We will not deadlock here because 1222 * we are blocking waiting for I/O that is already in-progress 1223 * to complete. We do not block here if it is the update 1224 * or syncer daemon trying to clean up as that can lead 1225 * to deadlock. 1226 */ 1227 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md) 1228 waitrunningbufspace(); 1229 } 1230 1231 return (0); 1232} 1233 1234void 1235bufbdflush(struct bufobj *bo, struct buf *bp) 1236{ 1237 struct buf *nbp; 1238 1239 if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10) { 1240 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); 1241 altbufferflushes++; 1242 } else if (bo->bo_dirty.bv_cnt > dirtybufthresh) { 1243 BO_LOCK(bo); 1244 /* 1245 * Try to find a buffer to flush. 1246 */ 1247 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 1248 if ((nbp->b_vflags & BV_BKGRDINPROG) || 1249 BUF_LOCK(nbp, 1250 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 1251 continue; 1252 if (bp == nbp) 1253 panic("bdwrite: found ourselves"); 1254 BO_UNLOCK(bo); 1255 /* Don't countdeps with the bo lock held. */ 1256 if (buf_countdeps(nbp, 0)) { 1257 BO_LOCK(bo); 1258 BUF_UNLOCK(nbp); 1259 continue; 1260 } 1261 if (nbp->b_flags & B_CLUSTEROK) { 1262 vfs_bio_awrite(nbp); 1263 } else { 1264 bremfree(nbp); 1265 bawrite(nbp); 1266 } 1267 dirtybufferflushes++; 1268 break; 1269 } 1270 if (nbp == NULL) 1271 BO_UNLOCK(bo); 1272 } 1273} 1274 1275/* 1276 * Delayed write. (Buffer is marked dirty). Do not bother writing 1277 * anything if the buffer is marked invalid. 1278 * 1279 * Note that since the buffer must be completely valid, we can safely 1280 * set B_CACHE. In fact, we have to set B_CACHE here rather then in 1281 * biodone() in order to prevent getblk from writing the buffer 1282 * out synchronously. 1283 */ 1284void 1285bdwrite(struct buf *bp) 1286{ 1287 struct thread *td = curthread; 1288 struct vnode *vp; 1289 struct bufobj *bo; 1290 1291 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1292 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 1293 KASSERT((bp->b_flags & B_BARRIER) == 0, 1294 ("Barrier request in delayed write %p", bp)); 1295 BUF_ASSERT_HELD(bp); 1296 1297 if (bp->b_flags & B_INVAL) { 1298 brelse(bp); 1299 return; 1300 } 1301 1302 /* 1303 * If we have too many dirty buffers, don't create any more. 1304 * If we are wildly over our limit, then force a complete 1305 * cleanup. Otherwise, just keep the situation from getting 1306 * out of control. Note that we have to avoid a recursive 1307 * disaster and not try to clean up after our own cleanup! 1308 */ 1309 vp = bp->b_vp; 1310 bo = bp->b_bufobj; 1311 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) { 1312 td->td_pflags |= TDP_INBDFLUSH; 1313 BO_BDFLUSH(bo, bp); 1314 td->td_pflags &= ~TDP_INBDFLUSH; 1315 } else 1316 recursiveflushes++; 1317 1318 bdirty(bp); 1319 /* 1320 * Set B_CACHE, indicating that the buffer is fully valid. This is 1321 * true even of NFS now. 1322 */ 1323 bp->b_flags |= B_CACHE; 1324 1325 /* 1326 * This bmap keeps the system from needing to do the bmap later, 1327 * perhaps when the system is attempting to do a sync. Since it 1328 * is likely that the indirect block -- or whatever other datastructure 1329 * that the filesystem needs is still in memory now, it is a good 1330 * thing to do this. Note also, that if the pageout daemon is 1331 * requesting a sync -- there might not be enough memory to do 1332 * the bmap then... So, this is important to do. 1333 */ 1334 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) { 1335 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1336 } 1337 1338 /* 1339 * Set the *dirty* buffer range based upon the VM system dirty 1340 * pages. 1341 * 1342 * Mark the buffer pages as clean. We need to do this here to 1343 * satisfy the vnode_pager and the pageout daemon, so that it 1344 * thinks that the pages have been "cleaned". Note that since 1345 * the pages are in a delayed write buffer -- the VFS layer 1346 * "will" see that the pages get written out on the next sync, 1347 * or perhaps the cluster will be completed. 1348 */ 1349 vfs_clean_pages_dirty_buf(bp); 1350 bqrelse(bp); 1351 1352 /* 1353 * note: we cannot initiate I/O from a bdwrite even if we wanted to, 1354 * due to the softdep code. 1355 */ 1356} 1357 1358/* 1359 * bdirty: 1360 * 1361 * Turn buffer into delayed write request. We must clear BIO_READ and 1362 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to 1363 * itself to properly update it in the dirty/clean lists. We mark it 1364 * B_DONE to ensure that any asynchronization of the buffer properly 1365 * clears B_DONE ( else a panic will occur later ). 1366 * 1367 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which 1368 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty() 1369 * should only be called if the buffer is known-good. 1370 * 1371 * Since the buffer is not on a queue, we do not update the numfreebuffers 1372 * count. 1373 * 1374 * The buffer must be on QUEUE_NONE. 1375 */ 1376void 1377bdirty(struct buf *bp) 1378{ 1379 1380 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X", 1381 bp, bp->b_vp, bp->b_flags); 1382 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 1383 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 1384 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex)); 1385 BUF_ASSERT_HELD(bp); 1386 bp->b_flags &= ~(B_RELBUF); 1387 bp->b_iocmd = BIO_WRITE; 1388 1389 if ((bp->b_flags & B_DELWRI) == 0) { 1390 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI; 1391 reassignbuf(bp); 1392 bdirtyadd(); 1393 } 1394} 1395 1396/* 1397 * bundirty: 1398 * 1399 * Clear B_DELWRI for buffer. 1400 * 1401 * Since the buffer is not on a queue, we do not update the numfreebuffers 1402 * count. 1403 * 1404 * The buffer must be on QUEUE_NONE. 1405 */ 1406 1407void 1408bundirty(struct buf *bp) 1409{ 1410 1411 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1412 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 1413 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 1414 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex)); 1415 BUF_ASSERT_HELD(bp); 1416 1417 if (bp->b_flags & B_DELWRI) { 1418 bp->b_flags &= ~B_DELWRI; 1419 reassignbuf(bp); 1420 bdirtysub(); 1421 } 1422 /* 1423 * Since it is now being written, we can clear its deferred write flag. 1424 */ 1425 bp->b_flags &= ~B_DEFERRED; 1426} 1427 1428/* 1429 * bawrite: 1430 * 1431 * Asynchronous write. Start output on a buffer, but do not wait for 1432 * it to complete. The buffer is released when the output completes. 1433 * 1434 * bwrite() ( or the VOP routine anyway ) is responsible for handling 1435 * B_INVAL buffers. Not us. 1436 */ 1437void 1438bawrite(struct buf *bp) 1439{ 1440 1441 bp->b_flags |= B_ASYNC; 1442 (void) bwrite(bp); 1443} 1444 1445/* 1446 * babarrierwrite: 1447 * 1448 * Asynchronous barrier write. Start output on a buffer, but do not 1449 * wait for it to complete. Place a write barrier after this write so 1450 * that this buffer and all buffers written before it are committed to 1451 * the disk before any buffers written after this write are committed 1452 * to the disk. The buffer is released when the output completes. 1453 */ 1454void 1455babarrierwrite(struct buf *bp) 1456{ 1457 1458 bp->b_flags |= B_ASYNC | B_BARRIER; 1459 (void) bwrite(bp); 1460} 1461 1462/* 1463 * bbarrierwrite: 1464 * 1465 * Synchronous barrier write. Start output on a buffer and wait for 1466 * it to complete. Place a write barrier after this write so that 1467 * this buffer and all buffers written before it are committed to 1468 * the disk before any buffers written after this write are committed 1469 * to the disk. The buffer is released when the output completes. 1470 */ 1471int 1472bbarrierwrite(struct buf *bp) 1473{ 1474 1475 bp->b_flags |= B_BARRIER; 1476 return (bwrite(bp)); 1477} 1478 1479/* 1480 * bwillwrite: 1481 * 1482 * Called prior to the locking of any vnodes when we are expecting to 1483 * write. We do not want to starve the buffer cache with too many 1484 * dirty buffers so we block here. By blocking prior to the locking 1485 * of any vnodes we attempt to avoid the situation where a locked vnode 1486 * prevents the various system daemons from flushing related buffers. 1487 */ 1488void 1489bwillwrite(void) 1490{ 1491 1492 if (numdirtybuffers >= hidirtybuffers) { 1493 mtx_lock(&bdirtylock); 1494 while (numdirtybuffers >= hidirtybuffers) { 1495 bdirtywait = 1; 1496 msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4), 1497 "flswai", 0); 1498 } 1499 mtx_unlock(&bdirtylock); 1500 } 1501} 1502 1503/* 1504 * Return true if we have too many dirty buffers. 1505 */ 1506int 1507buf_dirty_count_severe(void) 1508{ 1509 1510 return(numdirtybuffers >= hidirtybuffers); 1511} 1512 1513static __noinline int 1514buf_vm_page_count_severe(void) 1515{ 1516 1517 KFAIL_POINT_CODE(DEBUG_FP, buf_pressure, return 1); 1518 1519 return vm_page_count_severe(); 1520} 1521 1522/* 1523 * brelse: 1524 * 1525 * Release a busy buffer and, if requested, free its resources. The 1526 * buffer will be stashed in the appropriate bufqueue[] allowing it 1527 * to be accessed later as a cache entity or reused for other purposes. 1528 */ 1529void 1530brelse(struct buf *bp) 1531{ 1532 int qindex; 1533 1534 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X", 1535 bp, bp->b_vp, bp->b_flags); 1536 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 1537 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 1538 1539 if (BUF_LOCKRECURSED(bp)) { 1540 /* 1541 * Do not process, in particular, do not handle the 1542 * B_INVAL/B_RELBUF and do not release to free list. 1543 */ 1544 BUF_UNLOCK(bp); 1545 return; 1546 } 1547 1548 if (bp->b_flags & B_MANAGED) { 1549 bqrelse(bp); 1550 return; 1551 } 1552 1553 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 1554 bp->b_error == EIO && !(bp->b_flags & B_INVAL)) { 1555 /* 1556 * Failed write, redirty. Must clear BIO_ERROR to prevent 1557 * pages from being scrapped. If the error is anything 1558 * other than an I/O error (EIO), assume that retrying 1559 * is futile. 1560 */ 1561 bp->b_ioflags &= ~BIO_ERROR; 1562 bdirty(bp); 1563 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) || 1564 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) { 1565 /* 1566 * Either a failed I/O or we were asked to free or not 1567 * cache the buffer. 1568 */ 1569 bp->b_flags |= B_INVAL; 1570 if (!LIST_EMPTY(&bp->b_dep)) 1571 buf_deallocate(bp); 1572 if (bp->b_flags & B_DELWRI) 1573 bdirtysub(); 1574 bp->b_flags &= ~(B_DELWRI | B_CACHE); 1575 if ((bp->b_flags & B_VMIO) == 0) { 1576 if (bp->b_bufsize) 1577 allocbuf(bp, 0); 1578 if (bp->b_vp) 1579 brelvp(bp); 1580 } 1581 } 1582 1583 /* 1584 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_release() 1585 * is called with B_DELWRI set, the underlying pages may wind up 1586 * getting freed causing a previous write (bdwrite()) to get 'lost' 1587 * because pages associated with a B_DELWRI bp are marked clean. 1588 * 1589 * We still allow the B_INVAL case to call vfs_vmio_release(), even 1590 * if B_DELWRI is set. 1591 * 1592 * If B_DELWRI is not set we may have to set B_RELBUF if we are low 1593 * on pages to return pages to the VM page queues. 1594 */ 1595 if (bp->b_flags & B_DELWRI) 1596 bp->b_flags &= ~B_RELBUF; 1597 else if (buf_vm_page_count_severe()) { 1598 /* 1599 * BKGRDINPROG can only be set with the buf and bufobj 1600 * locks both held. We tolerate a race to clear it here. 1601 */ 1602 if (!(bp->b_vflags & BV_BKGRDINPROG)) 1603 bp->b_flags |= B_RELBUF; 1604 } 1605 1606 /* 1607 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 1608 * constituted, not even NFS buffers now. Two flags effect this. If 1609 * B_INVAL, the struct buf is invalidated but the VM object is kept 1610 * around ( i.e. so it is trivial to reconstitute the buffer later ). 1611 * 1612 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be 1613 * invalidated. BIO_ERROR cannot be set for a failed write unless the 1614 * buffer is also B_INVAL because it hits the re-dirtying code above. 1615 * 1616 * Normally we can do this whether a buffer is B_DELWRI or not. If 1617 * the buffer is an NFS buffer, it is tracking piecemeal writes or 1618 * the commit state and we cannot afford to lose the buffer. If the 1619 * buffer has a background write in progress, we need to keep it 1620 * around to prevent it from being reconstituted and starting a second 1621 * background write. 1622 */ 1623 if ((bp->b_flags & B_VMIO) 1624 && !(bp->b_vp->v_mount != NULL && 1625 (bp->b_vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 && 1626 !vn_isdisk(bp->b_vp, NULL) && 1627 (bp->b_flags & B_DELWRI)) 1628 ) { 1629 1630 int i, j, resid; 1631 vm_page_t m; 1632 off_t foff; 1633 vm_pindex_t poff; 1634 vm_object_t obj; 1635 1636 obj = bp->b_bufobj->bo_object; 1637 1638 /* 1639 * Get the base offset and length of the buffer. Note that 1640 * in the VMIO case if the buffer block size is not 1641 * page-aligned then b_data pointer may not be page-aligned. 1642 * But our b_pages[] array *IS* page aligned. 1643 * 1644 * block sizes less then DEV_BSIZE (usually 512) are not 1645 * supported due to the page granularity bits (m->valid, 1646 * m->dirty, etc...). 1647 * 1648 * See man buf(9) for more information 1649 */ 1650 resid = bp->b_bufsize; 1651 foff = bp->b_offset; 1652 for (i = 0; i < bp->b_npages; i++) { 1653 int had_bogus = 0; 1654 1655 m = bp->b_pages[i]; 1656 1657 /* 1658 * If we hit a bogus page, fixup *all* the bogus pages 1659 * now. 1660 */ 1661 if (m == bogus_page) { 1662 poff = OFF_TO_IDX(bp->b_offset); 1663 had_bogus = 1; 1664 1665 VM_OBJECT_RLOCK(obj); 1666 for (j = i; j < bp->b_npages; j++) { 1667 vm_page_t mtmp; 1668 mtmp = bp->b_pages[j]; 1669 if (mtmp == bogus_page) { 1670 mtmp = vm_page_lookup(obj, poff + j); 1671 if (!mtmp) { 1672 panic("brelse: page missing\n"); 1673 } 1674 bp->b_pages[j] = mtmp; 1675 } 1676 } 1677 VM_OBJECT_RUNLOCK(obj); 1678 1679 if ((bp->b_flags & (B_INVAL | B_UNMAPPED)) == 0) { 1680 BUF_CHECK_MAPPED(bp); 1681 pmap_qenter( 1682 trunc_page((vm_offset_t)bp->b_data), 1683 bp->b_pages, bp->b_npages); 1684 } 1685 m = bp->b_pages[i]; 1686 } 1687 if ((bp->b_flags & B_NOCACHE) || 1688 (bp->b_ioflags & BIO_ERROR && 1689 bp->b_iocmd == BIO_READ)) { 1690 int poffset = foff & PAGE_MASK; 1691 int presid = resid > (PAGE_SIZE - poffset) ? 1692 (PAGE_SIZE - poffset) : resid; 1693 1694 KASSERT(presid >= 0, ("brelse: extra page")); 1695 VM_OBJECT_WLOCK(obj); 1696 while (vm_page_xbusied(m)) { 1697 vm_page_lock(m); 1698 VM_OBJECT_WUNLOCK(obj); 1699 vm_page_busy_sleep(m, "mbncsh"); 1700 VM_OBJECT_WLOCK(obj); 1701 } 1702 if (pmap_page_wired_mappings(m) == 0) 1703 vm_page_set_invalid(m, poffset, presid); 1704 VM_OBJECT_WUNLOCK(obj); 1705 if (had_bogus) 1706 printf("avoided corruption bug in bogus_page/brelse code\n"); 1707 } 1708 resid -= PAGE_SIZE - (foff & PAGE_MASK); 1709 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 1710 } 1711 if (bp->b_flags & (B_INVAL | B_RELBUF)) 1712 vfs_vmio_release(bp); 1713 1714 } else if (bp->b_flags & B_VMIO) { 1715 1716 if (bp->b_flags & (B_INVAL | B_RELBUF)) { 1717 vfs_vmio_release(bp); 1718 } 1719 1720 } else if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0) { 1721 if (bp->b_bufsize != 0) 1722 allocbuf(bp, 0); 1723 if (bp->b_vp != NULL) 1724 brelvp(bp); 1725 } 1726 1727 /* 1728 * If the buffer has junk contents signal it and eventually 1729 * clean up B_DELWRI and diassociate the vnode so that gbincore() 1730 * doesn't find it. 1731 */ 1732 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 || 1733 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0) 1734 bp->b_flags |= B_INVAL; 1735 if (bp->b_flags & B_INVAL) { 1736 if (bp->b_flags & B_DELWRI) 1737 bundirty(bp); 1738 if (bp->b_vp) 1739 brelvp(bp); 1740 } 1741 1742 /* buffers with no memory */ 1743 if (bp->b_bufsize == 0) { 1744 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 1745 if (bp->b_vflags & BV_BKGRDINPROG) 1746 panic("losing buffer 1"); 1747 if (bp->b_kvasize) 1748 qindex = QUEUE_EMPTYKVA; 1749 else 1750 qindex = QUEUE_EMPTY; 1751 bp->b_flags |= B_AGE; 1752 /* buffers with junk contents */ 1753 } else if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) || 1754 (bp->b_ioflags & BIO_ERROR)) { 1755 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 1756 if (bp->b_vflags & BV_BKGRDINPROG) 1757 panic("losing buffer 2"); 1758 qindex = QUEUE_CLEAN; 1759 bp->b_flags |= B_AGE; 1760 /* remaining buffers */ 1761 } else if (bp->b_flags & B_DELWRI) 1762 qindex = QUEUE_DIRTY; 1763 else 1764 qindex = QUEUE_CLEAN; 1765 1766 binsfree(bp, qindex); 1767 1768 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF | B_DIRECT); 1769 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) 1770 panic("brelse: not dirty"); 1771 /* unlock */ 1772 BUF_UNLOCK(bp); 1773} 1774 1775/* 1776 * Release a buffer back to the appropriate queue but do not try to free 1777 * it. The buffer is expected to be used again soon. 1778 * 1779 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by 1780 * biodone() to requeue an async I/O on completion. It is also used when 1781 * known good buffers need to be requeued but we think we may need the data 1782 * again soon. 1783 * 1784 * XXX we should be able to leave the B_RELBUF hint set on completion. 1785 */ 1786void 1787bqrelse(struct buf *bp) 1788{ 1789 int qindex; 1790 1791 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1792 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 1793 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 1794 1795 if (BUF_LOCKRECURSED(bp)) { 1796 /* do not release to free list */ 1797 BUF_UNLOCK(bp); 1798 return; 1799 } 1800 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 1801 1802 if (bp->b_flags & B_MANAGED) { 1803 if (bp->b_flags & B_REMFREE) 1804 bremfreef(bp); 1805 goto out; 1806 } 1807 1808 /* buffers with stale but valid contents */ 1809 if (bp->b_flags & B_DELWRI) { 1810 qindex = QUEUE_DIRTY; 1811 } else { 1812 if ((bp->b_flags & B_DELWRI) == 0 && 1813 (bp->b_xflags & BX_VNDIRTY)) 1814 panic("bqrelse: not dirty"); 1815 /* 1816 * BKGRDINPROG can only be set with the buf and bufobj 1817 * locks both held. We tolerate a race to clear it here. 1818 */ 1819 if (buf_vm_page_count_severe() && 1820 (bp->b_vflags & BV_BKGRDINPROG) == 0) { 1821 /* 1822 * We are too low on memory, we have to try to free 1823 * the buffer (most importantly: the wired pages 1824 * making up its backing store) *now*. 1825 */ 1826 brelse(bp); 1827 return; 1828 } 1829 qindex = QUEUE_CLEAN; 1830 } 1831 binsfree(bp, qindex); 1832 1833out: 1834 /* unlock */ 1835 BUF_UNLOCK(bp); 1836} 1837 1838/* Give pages used by the bp back to the VM system (where possible) */ 1839static void 1840vfs_vmio_release(struct buf *bp) 1841{ 1842 int i; 1843 vm_page_t m; 1844 1845 if ((bp->b_flags & B_UNMAPPED) == 0) { 1846 BUF_CHECK_MAPPED(bp); 1847 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages); 1848 } else 1849 BUF_CHECK_UNMAPPED(bp); 1850 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 1851 for (i = 0; i < bp->b_npages; i++) { 1852 m = bp->b_pages[i]; 1853 bp->b_pages[i] = NULL; 1854 /* 1855 * In order to keep page LRU ordering consistent, put 1856 * everything on the inactive queue. 1857 */ 1858 vm_page_lock(m); 1859 vm_page_unwire(m, 0); 1860 1861 /* 1862 * Might as well free the page if we can and it has 1863 * no valid data. We also free the page if the 1864 * buffer was used for direct I/O 1865 */ 1866 if ((bp->b_flags & B_ASYNC) == 0 && !m->valid) { 1867 if (m->wire_count == 0 && !vm_page_busied(m)) 1868 vm_page_free(m); 1869 } else if (bp->b_flags & B_DIRECT) 1870 vm_page_try_to_free(m); 1871 else if (buf_vm_page_count_severe()) 1872 vm_page_try_to_cache(m); 1873 vm_page_unlock(m); 1874 } 1875 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 1876 1877 if (bp->b_bufsize) { 1878 bufspacewakeup(); 1879 bp->b_bufsize = 0; 1880 } 1881 bp->b_npages = 0; 1882 bp->b_flags &= ~B_VMIO; 1883 if (bp->b_vp) 1884 brelvp(bp); 1885} 1886 1887/* 1888 * Check to see if a block at a particular lbn is available for a clustered 1889 * write. 1890 */ 1891static int 1892vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno) 1893{ 1894 struct buf *bpa; 1895 int match; 1896 1897 match = 0; 1898 1899 /* If the buf isn't in core skip it */ 1900 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL) 1901 return (0); 1902 1903 /* If the buf is busy we don't want to wait for it */ 1904 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 1905 return (0); 1906 1907 /* Only cluster with valid clusterable delayed write buffers */ 1908 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) != 1909 (B_DELWRI | B_CLUSTEROK)) 1910 goto done; 1911 1912 if (bpa->b_bufsize != size) 1913 goto done; 1914 1915 /* 1916 * Check to see if it is in the expected place on disk and that the 1917 * block has been mapped. 1918 */ 1919 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno)) 1920 match = 1; 1921done: 1922 BUF_UNLOCK(bpa); 1923 return (match); 1924} 1925 1926/* 1927 * vfs_bio_awrite: 1928 * 1929 * Implement clustered async writes for clearing out B_DELWRI buffers. 1930 * This is much better then the old way of writing only one buffer at 1931 * a time. Note that we may not be presented with the buffers in the 1932 * correct order, so we search for the cluster in both directions. 1933 */ 1934int 1935vfs_bio_awrite(struct buf *bp) 1936{ 1937 struct bufobj *bo; 1938 int i; 1939 int j; 1940 daddr_t lblkno = bp->b_lblkno; 1941 struct vnode *vp = bp->b_vp; 1942 int ncl; 1943 int nwritten; 1944 int size; 1945 int maxcl; 1946 int gbflags; 1947 1948 bo = &vp->v_bufobj; 1949 gbflags = (bp->b_flags & B_UNMAPPED) != 0 ? GB_UNMAPPED : 0; 1950 /* 1951 * right now we support clustered writing only to regular files. If 1952 * we find a clusterable block we could be in the middle of a cluster 1953 * rather then at the beginning. 1954 */ 1955 if ((vp->v_type == VREG) && 1956 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 1957 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 1958 1959 size = vp->v_mount->mnt_stat.f_iosize; 1960 maxcl = MAXPHYS / size; 1961 1962 BO_RLOCK(bo); 1963 for (i = 1; i < maxcl; i++) 1964 if (vfs_bio_clcheck(vp, size, lblkno + i, 1965 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0) 1966 break; 1967 1968 for (j = 1; i + j <= maxcl && j <= lblkno; j++) 1969 if (vfs_bio_clcheck(vp, size, lblkno - j, 1970 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0) 1971 break; 1972 BO_RUNLOCK(bo); 1973 --j; 1974 ncl = i + j; 1975 /* 1976 * this is a possible cluster write 1977 */ 1978 if (ncl != 1) { 1979 BUF_UNLOCK(bp); 1980 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, 1981 gbflags); 1982 return (nwritten); 1983 } 1984 } 1985 bremfree(bp); 1986 bp->b_flags |= B_ASYNC; 1987 /* 1988 * default (old) behavior, writing out only one block 1989 * 1990 * XXX returns b_bufsize instead of b_bcount for nwritten? 1991 */ 1992 nwritten = bp->b_bufsize; 1993 (void) bwrite(bp); 1994 1995 return (nwritten); 1996} 1997 1998static void 1999setbufkva(struct buf *bp, vm_offset_t addr, int maxsize, int gbflags) 2000{ 2001 2002 KASSERT((bp->b_flags & (B_UNMAPPED | B_KVAALLOC)) == 0 && 2003 bp->b_kvasize == 0, ("call bfreekva(%p)", bp)); 2004 if ((gbflags & GB_UNMAPPED) == 0) { 2005 bp->b_kvabase = (caddr_t)addr; 2006 } else if ((gbflags & GB_KVAALLOC) != 0) { 2007 KASSERT((gbflags & GB_UNMAPPED) != 0, 2008 ("GB_KVAALLOC without GB_UNMAPPED")); 2009 bp->b_kvaalloc = (caddr_t)addr; 2010 bp->b_flags |= B_UNMAPPED | B_KVAALLOC; 2011 atomic_add_long(&unmapped_bufspace, bp->b_kvasize); 2012 } 2013 bp->b_kvasize = maxsize; 2014} 2015 2016/* 2017 * Allocate the buffer KVA and set b_kvasize. Also set b_kvabase if 2018 * needed. 2019 */ 2020static int 2021allocbufkva(struct buf *bp, int maxsize, int gbflags) 2022{ 2023 vm_offset_t addr; 2024 2025 bfreekva(bp); 2026 addr = 0; 2027 2028 if (vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr)) { 2029 /* 2030 * Buffer map is too fragmented. Request the caller 2031 * to defragment the map. 2032 */ 2033 atomic_add_int(&bufdefragcnt, 1); 2034 return (1); 2035 } 2036 setbufkva(bp, addr, maxsize, gbflags); 2037 atomic_add_long(&bufspace, bp->b_kvasize); 2038 return (0); 2039} 2040 2041/* 2042 * Ask the bufdaemon for help, or act as bufdaemon itself, when a 2043 * locked vnode is supplied. 2044 */ 2045static void 2046getnewbuf_bufd_help(struct vnode *vp, int gbflags, int slpflag, int slptimeo, 2047 int defrag) 2048{ 2049 struct thread *td; 2050 char *waitmsg; 2051 int cnt, error, flags, norunbuf, wait; 2052 2053 mtx_assert(&bqclean, MA_OWNED); 2054 2055 if (defrag) { 2056 flags = VFS_BIO_NEED_BUFSPACE; 2057 waitmsg = "nbufkv"; 2058 } else if (bufspace >= hibufspace) { 2059 waitmsg = "nbufbs"; 2060 flags = VFS_BIO_NEED_BUFSPACE; 2061 } else { 2062 waitmsg = "newbuf"; 2063 flags = VFS_BIO_NEED_ANY; 2064 } 2065 mtx_lock(&nblock); 2066 needsbuffer |= flags; 2067 mtx_unlock(&nblock); 2068 mtx_unlock(&bqclean); 2069 2070 bd_speedup(); /* heeeelp */ 2071 if ((gbflags & GB_NOWAIT_BD) != 0) 2072 return; 2073 2074 td = curthread; 2075 cnt = 0; 2076 wait = MNT_NOWAIT; 2077 mtx_lock(&nblock); 2078 while (needsbuffer & flags) { 2079 if (vp != NULL && vp->v_type != VCHR && 2080 (td->td_pflags & TDP_BUFNEED) == 0) { 2081 mtx_unlock(&nblock); 2082 2083 /* 2084 * getblk() is called with a vnode locked, and 2085 * some majority of the dirty buffers may as 2086 * well belong to the vnode. Flushing the 2087 * buffers there would make a progress that 2088 * cannot be achieved by the buf_daemon, that 2089 * cannot lock the vnode. 2090 */ 2091 if (cnt++ > 2) 2092 wait = MNT_WAIT; 2093 ASSERT_VOP_LOCKED(vp, "bufd_helper"); 2094 error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : 2095 vn_lock(vp, LK_TRYUPGRADE); 2096 if (error == 0) { 2097 /* play bufdaemon */ 2098 norunbuf = curthread_pflags_set(TDP_BUFNEED | 2099 TDP_NORUNNINGBUF); 2100 VOP_FSYNC(vp, wait, td); 2101 atomic_add_long(¬bufdflushes, 1); 2102 curthread_pflags_restore(norunbuf); 2103 } 2104 mtx_lock(&nblock); 2105 if ((needsbuffer & flags) == 0) 2106 break; 2107 } 2108 if (msleep(&needsbuffer, &nblock, (PRIBIO + 4) | slpflag, 2109 waitmsg, slptimeo)) 2110 break; 2111 } 2112 mtx_unlock(&nblock); 2113} 2114 2115static void 2116getnewbuf_reuse_bp(struct buf *bp, int qindex) 2117{ 2118 2119 CTR6(KTR_BUF, "getnewbuf(%p) vp %p flags %X kvasize %d bufsize %d " 2120 "queue %d (recycling)", bp, bp->b_vp, bp->b_flags, 2121 bp->b_kvasize, bp->b_bufsize, qindex); 2122 mtx_assert(&bqclean, MA_NOTOWNED); 2123 2124 /* 2125 * Note: we no longer distinguish between VMIO and non-VMIO 2126 * buffers. 2127 */ 2128 KASSERT((bp->b_flags & B_DELWRI) == 0, 2129 ("delwri buffer %p found in queue %d", bp, qindex)); 2130 2131 if (qindex == QUEUE_CLEAN) { 2132 if (bp->b_flags & B_VMIO) { 2133 bp->b_flags &= ~B_ASYNC; 2134 vfs_vmio_release(bp); 2135 } 2136 if (bp->b_vp != NULL) 2137 brelvp(bp); 2138 } 2139 2140 /* 2141 * Get the rest of the buffer freed up. b_kva* is still valid 2142 * after this operation. 2143 */ 2144 2145 if (bp->b_rcred != NOCRED) { 2146 crfree(bp->b_rcred); 2147 bp->b_rcred = NOCRED; 2148 } 2149 if (bp->b_wcred != NOCRED) { 2150 crfree(bp->b_wcred); 2151 bp->b_wcred = NOCRED; 2152 } 2153 if (!LIST_EMPTY(&bp->b_dep)) 2154 buf_deallocate(bp); 2155 if (bp->b_vflags & BV_BKGRDINPROG) 2156 panic("losing buffer 3"); 2157 KASSERT(bp->b_vp == NULL, ("bp: %p still has vnode %p. qindex: %d", 2158 bp, bp->b_vp, qindex)); 2159 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0, 2160 ("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags)); 2161 2162 if (bp->b_bufsize) 2163 allocbuf(bp, 0); 2164 2165 bp->b_flags &= B_UNMAPPED | B_KVAALLOC; 2166 bp->b_ioflags = 0; 2167 bp->b_xflags = 0; 2168 KASSERT((bp->b_flags & B_INFREECNT) == 0, 2169 ("buf %p still counted as free?", bp)); 2170 bp->b_vflags = 0; 2171 bp->b_vp = NULL; 2172 bp->b_blkno = bp->b_lblkno = 0; 2173 bp->b_offset = NOOFFSET; 2174 bp->b_iodone = 0; 2175 bp->b_error = 0; 2176 bp->b_resid = 0; 2177 bp->b_bcount = 0; 2178 bp->b_npages = 0; 2179 bp->b_dirtyoff = bp->b_dirtyend = 0; 2180 bp->b_bufobj = NULL; 2181 bp->b_pin_count = 0; 2182 bp->b_fsprivate1 = NULL; 2183 bp->b_fsprivate2 = NULL; 2184 bp->b_fsprivate3 = NULL; 2185 2186 LIST_INIT(&bp->b_dep); 2187} 2188 2189static int flushingbufs; 2190 2191static struct buf * 2192getnewbuf_scan(int maxsize, int defrag, int unmapped, int metadata) 2193{ 2194 struct buf *bp, *nbp; 2195 int nqindex, qindex, pass; 2196 2197 KASSERT(!unmapped || !defrag, ("both unmapped and defrag")); 2198 2199 pass = 1; 2200restart: 2201 atomic_add_int(&getnewbufrestarts, 1); 2202 2203 /* 2204 * Setup for scan. If we do not have enough free buffers, 2205 * we setup a degenerate case that immediately fails. Note 2206 * that if we are specially marked process, we are allowed to 2207 * dip into our reserves. 2208 * 2209 * The scanning sequence is nominally: EMPTY->EMPTYKVA->CLEAN 2210 * for the allocation of the mapped buffer. For unmapped, the 2211 * easiest is to start with EMPTY outright. 2212 * 2213 * We start with EMPTYKVA. If the list is empty we backup to EMPTY. 2214 * However, there are a number of cases (defragging, reusing, ...) 2215 * where we cannot backup. 2216 */ 2217 nbp = NULL; 2218 mtx_lock(&bqclean); 2219 if (!defrag && unmapped) { 2220 nqindex = QUEUE_EMPTY; 2221 nbp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]); 2222 } 2223 if (nbp == NULL) { 2224 nqindex = QUEUE_EMPTYKVA; 2225 nbp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTYKVA]); 2226 } 2227 2228 /* 2229 * If no EMPTYKVA buffers and we are either defragging or 2230 * reusing, locate a CLEAN buffer to free or reuse. If 2231 * bufspace useage is low skip this step so we can allocate a 2232 * new buffer. 2233 */ 2234 if (nbp == NULL && (defrag || bufspace >= lobufspace)) { 2235 nqindex = QUEUE_CLEAN; 2236 nbp = TAILQ_FIRST(&bufqueues[QUEUE_CLEAN]); 2237 } 2238 2239 /* 2240 * If we could not find or were not allowed to reuse a CLEAN 2241 * buffer, check to see if it is ok to use an EMPTY buffer. 2242 * We can only use an EMPTY buffer if allocating its KVA would 2243 * not otherwise run us out of buffer space. No KVA is needed 2244 * for the unmapped allocation. 2245 */ 2246 if (nbp == NULL && defrag == 0 && (bufspace + maxsize < hibufspace || 2247 metadata)) { 2248 nqindex = QUEUE_EMPTY; 2249 nbp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]); 2250 } 2251 2252 /* 2253 * All available buffers might be clean, retry ignoring the 2254 * lobufspace as the last resort. 2255 */ 2256 if (nbp == NULL && !TAILQ_EMPTY(&bufqueues[QUEUE_CLEAN])) { 2257 nqindex = QUEUE_CLEAN; 2258 nbp = TAILQ_FIRST(&bufqueues[QUEUE_CLEAN]); 2259 } 2260 2261 /* 2262 * Run scan, possibly freeing data and/or kva mappings on the fly 2263 * depending. 2264 */ 2265 while ((bp = nbp) != NULL) { 2266 qindex = nqindex; 2267 2268 /* 2269 * Calculate next bp (we can only use it if we do not 2270 * block or do other fancy things). 2271 */ 2272 if ((nbp = TAILQ_NEXT(bp, b_freelist)) == NULL) { 2273 switch (qindex) { 2274 case QUEUE_EMPTY: 2275 nqindex = QUEUE_EMPTYKVA; 2276 nbp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTYKVA]); 2277 if (nbp != NULL) 2278 break; 2279 /* FALLTHROUGH */ 2280 case QUEUE_EMPTYKVA: 2281 nqindex = QUEUE_CLEAN; 2282 nbp = TAILQ_FIRST(&bufqueues[QUEUE_CLEAN]); 2283 if (nbp != NULL) 2284 break; 2285 /* FALLTHROUGH */ 2286 case QUEUE_CLEAN: 2287 if (metadata && pass == 1) { 2288 pass = 2; 2289 nqindex = QUEUE_EMPTY; 2290 nbp = TAILQ_FIRST( 2291 &bufqueues[QUEUE_EMPTY]); 2292 } 2293 /* 2294 * nbp is NULL. 2295 */ 2296 break; 2297 } 2298 } 2299 /* 2300 * If we are defragging then we need a buffer with 2301 * b_kvasize != 0. XXX this situation should no longer 2302 * occur, if defrag is non-zero the buffer's b_kvasize 2303 * should also be non-zero at this point. XXX 2304 */ 2305 if (defrag && bp->b_kvasize == 0) { 2306 printf("Warning: defrag empty buffer %p\n", bp); 2307 continue; 2308 } 2309 2310 /* 2311 * Start freeing the bp. This is somewhat involved. nbp 2312 * remains valid only for QUEUE_EMPTY[KVA] bp's. 2313 */ 2314 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 2315 continue; 2316 /* 2317 * BKGRDINPROG can only be set with the buf and bufobj 2318 * locks both held. We tolerate a race to clear it here. 2319 */ 2320 if (bp->b_vflags & BV_BKGRDINPROG) { 2321 BUF_UNLOCK(bp); 2322 continue; 2323 } 2324 2325 KASSERT(bp->b_qindex == qindex, 2326 ("getnewbuf: inconsistent queue %d bp %p", qindex, bp)); 2327 2328 bremfreel(bp); 2329 mtx_unlock(&bqclean); 2330 /* 2331 * NOTE: nbp is now entirely invalid. We can only restart 2332 * the scan from this point on. 2333 */ 2334 2335 getnewbuf_reuse_bp(bp, qindex); 2336 mtx_assert(&bqclean, MA_NOTOWNED); 2337 2338 /* 2339 * If we are defragging then free the buffer. 2340 */ 2341 if (defrag) { 2342 bp->b_flags |= B_INVAL; 2343 bfreekva(bp); 2344 brelse(bp); 2345 defrag = 0; 2346 goto restart; 2347 } 2348 2349 /* 2350 * Notify any waiters for the buffer lock about 2351 * identity change by freeing the buffer. 2352 */ 2353 if (qindex == QUEUE_CLEAN && BUF_LOCKWAITERS(bp)) { 2354 bp->b_flags |= B_INVAL; 2355 bfreekva(bp); 2356 brelse(bp); 2357 goto restart; 2358 } 2359 2360 if (metadata) 2361 break; 2362 2363 /* 2364 * If we are overcomitted then recover the buffer and its 2365 * KVM space. This occurs in rare situations when multiple 2366 * processes are blocked in getnewbuf() or allocbuf(). 2367 */ 2368 if (bufspace >= hibufspace) 2369 flushingbufs = 1; 2370 if (flushingbufs && bp->b_kvasize != 0) { 2371 bp->b_flags |= B_INVAL; 2372 bfreekva(bp); 2373 brelse(bp); 2374 goto restart; 2375 } 2376 if (bufspace < lobufspace) 2377 flushingbufs = 0; 2378 break; 2379 } 2380 return (bp); 2381} 2382 2383/* 2384 * getnewbuf: 2385 * 2386 * Find and initialize a new buffer header, freeing up existing buffers 2387 * in the bufqueues as necessary. The new buffer is returned locked. 2388 * 2389 * Important: B_INVAL is not set. If the caller wishes to throw the 2390 * buffer away, the caller must set B_INVAL prior to calling brelse(). 2391 * 2392 * We block if: 2393 * We have insufficient buffer headers 2394 * We have insufficient buffer space 2395 * buffer_arena is too fragmented ( space reservation fails ) 2396 * If we have to flush dirty buffers ( but we try to avoid this ) 2397 */ 2398static struct buf * 2399getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int size, int maxsize, 2400 int gbflags) 2401{ 2402 struct buf *bp; 2403 int defrag, metadata; 2404 2405 KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 2406 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 2407 if (!unmapped_buf_allowed) 2408 gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC); 2409 2410 defrag = 0; 2411 if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 || 2412 vp->v_type == VCHR) 2413 metadata = 1; 2414 else 2415 metadata = 0; 2416 /* 2417 * We can't afford to block since we might be holding a vnode lock, 2418 * which may prevent system daemons from running. We deal with 2419 * low-memory situations by proactively returning memory and running 2420 * async I/O rather then sync I/O. 2421 */ 2422 atomic_add_int(&getnewbufcalls, 1); 2423 atomic_subtract_int(&getnewbufrestarts, 1); 2424restart: 2425 bp = getnewbuf_scan(maxsize, defrag, (gbflags & (GB_UNMAPPED | 2426 GB_KVAALLOC)) == GB_UNMAPPED, metadata); 2427 if (bp != NULL) 2428 defrag = 0; 2429 2430 /* 2431 * If we exhausted our list, sleep as appropriate. We may have to 2432 * wakeup various daemons and write out some dirty buffers. 2433 * 2434 * Generally we are sleeping due to insufficient buffer space. 2435 */ 2436 if (bp == NULL) { 2437 mtx_assert(&bqclean, MA_OWNED); 2438 getnewbuf_bufd_help(vp, gbflags, slpflag, slptimeo, defrag); 2439 mtx_assert(&bqclean, MA_NOTOWNED); 2440 } else if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) == GB_UNMAPPED) { 2441 mtx_assert(&bqclean, MA_NOTOWNED); 2442 2443 bfreekva(bp); 2444 bp->b_flags |= B_UNMAPPED; 2445 bp->b_kvabase = bp->b_data = unmapped_buf; 2446 bp->b_kvasize = maxsize; 2447 atomic_add_long(&bufspace, bp->b_kvasize); 2448 atomic_add_long(&unmapped_bufspace, bp->b_kvasize); 2449 atomic_add_int(&bufreusecnt, 1); 2450 } else { 2451 mtx_assert(&bqclean, MA_NOTOWNED); 2452 2453 /* 2454 * We finally have a valid bp. We aren't quite out of the 2455 * woods, we still have to reserve kva space. In order 2456 * to keep fragmentation sane we only allocate kva in 2457 * BKVASIZE chunks. 2458 */ 2459 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK; 2460 2461 if (maxsize != bp->b_kvasize || (bp->b_flags & (B_UNMAPPED | 2462 B_KVAALLOC)) == B_UNMAPPED) { 2463 if (allocbufkva(bp, maxsize, gbflags)) { 2464 defrag = 1; 2465 bp->b_flags |= B_INVAL; 2466 brelse(bp); 2467 goto restart; 2468 } 2469 atomic_add_int(&bufreusecnt, 1); 2470 } else if ((bp->b_flags & B_KVAALLOC) != 0 && 2471 (gbflags & (GB_UNMAPPED | GB_KVAALLOC)) == 0) { 2472 /* 2473 * If the reused buffer has KVA allocated, 2474 * reassign b_kvaalloc to b_kvabase. 2475 */ 2476 bp->b_kvabase = bp->b_kvaalloc; 2477 bp->b_flags &= ~B_KVAALLOC; 2478 atomic_subtract_long(&unmapped_bufspace, 2479 bp->b_kvasize); 2480 atomic_add_int(&bufreusecnt, 1); 2481 } else if ((bp->b_flags & (B_UNMAPPED | B_KVAALLOC)) == 0 && 2482 (gbflags & (GB_UNMAPPED | GB_KVAALLOC)) == (GB_UNMAPPED | 2483 GB_KVAALLOC)) { 2484 /* 2485 * The case of reused buffer already have KVA 2486 * mapped, but the request is for unmapped 2487 * buffer with KVA allocated. 2488 */ 2489 bp->b_kvaalloc = bp->b_kvabase; 2490 bp->b_data = bp->b_kvabase = unmapped_buf; 2491 bp->b_flags |= B_UNMAPPED | B_KVAALLOC; 2492 atomic_add_long(&unmapped_bufspace, 2493 bp->b_kvasize); 2494 atomic_add_int(&bufreusecnt, 1); 2495 } 2496 if ((gbflags & GB_UNMAPPED) == 0) { 2497 bp->b_saveaddr = bp->b_kvabase; 2498 bp->b_data = bp->b_saveaddr; 2499 bp->b_flags &= ~B_UNMAPPED; 2500 BUF_CHECK_MAPPED(bp); 2501 } 2502 } 2503 return (bp); 2504} 2505 2506/* 2507 * buf_daemon: 2508 * 2509 * buffer flushing daemon. Buffers are normally flushed by the 2510 * update daemon but if it cannot keep up this process starts to 2511 * take the load in an attempt to prevent getnewbuf() from blocking. 2512 */ 2513 2514static struct kproc_desc buf_kp = { 2515 "bufdaemon", 2516 buf_daemon, 2517 &bufdaemonproc 2518}; 2519SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp); 2520 2521static int 2522buf_flush(int target) 2523{ 2524 int flushed; 2525 2526 flushed = flushbufqueues(target, 0); 2527 if (flushed == 0) { 2528 /* 2529 * Could not find any buffers without rollback 2530 * dependencies, so just write the first one 2531 * in the hopes of eventually making progress. 2532 */ 2533 flushed = flushbufqueues(target, 1); 2534 } 2535 return (flushed); 2536} 2537 2538static void 2539buf_daemon() 2540{ 2541 int lodirty; 2542 2543 /* 2544 * This process needs to be suspended prior to shutdown sync. 2545 */ 2546 EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, bufdaemonproc, 2547 SHUTDOWN_PRI_LAST); 2548 2549 /* 2550 * This process is allowed to take the buffer cache to the limit 2551 */ 2552 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED; 2553 mtx_lock(&bdlock); 2554 for (;;) { 2555 bd_request = 0; 2556 mtx_unlock(&bdlock); 2557 2558 kproc_suspend_check(bufdaemonproc); 2559 lodirty = lodirtybuffers; 2560 if (bd_speedupreq) { 2561 lodirty = numdirtybuffers / 2; 2562 bd_speedupreq = 0; 2563 } 2564 /* 2565 * Do the flush. Limit the amount of in-transit I/O we 2566 * allow to build up, otherwise we would completely saturate 2567 * the I/O system. 2568 */ 2569 while (numdirtybuffers > lodirty) { 2570 if (buf_flush(numdirtybuffers - lodirty) == 0) 2571 break; 2572 kern_yield(PRI_USER); 2573 } 2574 2575 /* 2576 * Only clear bd_request if we have reached our low water 2577 * mark. The buf_daemon normally waits 1 second and 2578 * then incrementally flushes any dirty buffers that have 2579 * built up, within reason. 2580 * 2581 * If we were unable to hit our low water mark and couldn't 2582 * find any flushable buffers, we sleep for a short period 2583 * to avoid endless loops on unlockable buffers. 2584 */ 2585 mtx_lock(&bdlock); 2586 if (numdirtybuffers <= lodirtybuffers) { 2587 /* 2588 * We reached our low water mark, reset the 2589 * request and sleep until we are needed again. 2590 * The sleep is just so the suspend code works. 2591 */ 2592 bd_request = 0; 2593 /* 2594 * Do an extra wakeup in case dirty threshold 2595 * changed via sysctl and the explicit transition 2596 * out of shortfall was missed. 2597 */ 2598 bdirtywakeup(); 2599 if (runningbufspace <= lorunningspace) 2600 runningwakeup(); 2601 msleep(&bd_request, &bdlock, PVM, "psleep", hz); 2602 } else { 2603 /* 2604 * We couldn't find any flushable dirty buffers but 2605 * still have too many dirty buffers, we 2606 * have to sleep and try again. (rare) 2607 */ 2608 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10); 2609 } 2610 } 2611} 2612 2613/* 2614 * flushbufqueues: 2615 * 2616 * Try to flush a buffer in the dirty queue. We must be careful to 2617 * free up B_INVAL buffers instead of write them, which NFS is 2618 * particularly sensitive to. 2619 */ 2620static int flushwithdeps = 0; 2621SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW, &flushwithdeps, 2622 0, "Number of buffers flushed with dependecies that require rollbacks"); 2623 2624static int 2625flushbufqueues(int target, int flushdeps) 2626{ 2627 struct buf *sentinel; 2628 struct vnode *vp; 2629 struct mount *mp; 2630 struct buf *bp; 2631 int hasdeps; 2632 int flushed; 2633 int queue; 2634 int error; 2635 2636 flushed = 0; 2637 queue = QUEUE_DIRTY; 2638 bp = NULL; 2639 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO); 2640 sentinel->b_qindex = QUEUE_SENTINEL; 2641 mtx_lock(&bqdirty); 2642 TAILQ_INSERT_HEAD(&bufqueues[queue], sentinel, b_freelist); 2643 mtx_unlock(&bqdirty); 2644 while (flushed != target) { 2645 maybe_yield(); 2646 mtx_lock(&bqdirty); 2647 bp = TAILQ_NEXT(sentinel, b_freelist); 2648 if (bp != NULL) { 2649 TAILQ_REMOVE(&bufqueues[queue], sentinel, b_freelist); 2650 TAILQ_INSERT_AFTER(&bufqueues[queue], bp, sentinel, 2651 b_freelist); 2652 } else { 2653 mtx_unlock(&bqdirty); 2654 break; 2655 } 2656 KASSERT(bp->b_qindex != QUEUE_SENTINEL, 2657 ("parallel calls to flushbufqueues() bp %p", bp)); 2658 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 2659 mtx_unlock(&bqdirty); 2660 if (error != 0) 2661 continue; 2662 if (bp->b_pin_count > 0) { 2663 BUF_UNLOCK(bp); 2664 continue; 2665 } 2666 /* 2667 * BKGRDINPROG can only be set with the buf and bufobj 2668 * locks both held. We tolerate a race to clear it here. 2669 */ 2670 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 || 2671 (bp->b_flags & B_DELWRI) == 0) { 2672 BUF_UNLOCK(bp); 2673 continue; 2674 } 2675 if (bp->b_flags & B_INVAL) { 2676 bremfreef(bp); 2677 brelse(bp); 2678 flushed++; 2679 continue; 2680 } 2681 2682 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) { 2683 if (flushdeps == 0) { 2684 BUF_UNLOCK(bp); 2685 continue; 2686 } 2687 hasdeps = 1; 2688 } else 2689 hasdeps = 0; 2690 /* 2691 * We must hold the lock on a vnode before writing 2692 * one of its buffers. Otherwise we may confuse, or 2693 * in the case of a snapshot vnode, deadlock the 2694 * system. 2695 * 2696 * The lock order here is the reverse of the normal 2697 * of vnode followed by buf lock. This is ok because 2698 * the NOWAIT will prevent deadlock. 2699 */ 2700 vp = bp->b_vp; 2701 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { 2702 BUF_UNLOCK(bp); 2703 continue; 2704 } 2705 error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); 2706 if (error == 0) { 2707 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", 2708 bp, bp->b_vp, bp->b_flags); 2709 vfs_bio_awrite(bp); 2710 vn_finished_write(mp); 2711 VOP_UNLOCK(vp, 0); 2712 flushwithdeps += hasdeps; 2713 flushed++; 2714 if (runningbufspace > hirunningspace) 2715 waitrunningbufspace(); 2716 continue; 2717 } 2718 vn_finished_write(mp); 2719 BUF_UNLOCK(bp); 2720 } 2721 mtx_lock(&bqdirty); 2722 TAILQ_REMOVE(&bufqueues[queue], sentinel, b_freelist); 2723 mtx_unlock(&bqdirty); 2724 free(sentinel, M_TEMP); 2725 return (flushed); 2726} 2727 2728/* 2729 * Check to see if a block is currently memory resident. 2730 */ 2731struct buf * 2732incore(struct bufobj *bo, daddr_t blkno) 2733{ 2734 struct buf *bp; 2735 2736 BO_RLOCK(bo); 2737 bp = gbincore(bo, blkno); 2738 BO_RUNLOCK(bo); 2739 return (bp); 2740} 2741 2742/* 2743 * Returns true if no I/O is needed to access the 2744 * associated VM object. This is like incore except 2745 * it also hunts around in the VM system for the data. 2746 */ 2747 2748static int 2749inmem(struct vnode * vp, daddr_t blkno) 2750{ 2751 vm_object_t obj; 2752 vm_offset_t toff, tinc, size; 2753 vm_page_t m; 2754 vm_ooffset_t off; 2755 2756 ASSERT_VOP_LOCKED(vp, "inmem"); 2757 2758 if (incore(&vp->v_bufobj, blkno)) 2759 return 1; 2760 if (vp->v_mount == NULL) 2761 return 0; 2762 obj = vp->v_object; 2763 if (obj == NULL) 2764 return (0); 2765 2766 size = PAGE_SIZE; 2767 if (size > vp->v_mount->mnt_stat.f_iosize) 2768 size = vp->v_mount->mnt_stat.f_iosize; 2769 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 2770 2771 VM_OBJECT_RLOCK(obj); 2772 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 2773 m = vm_page_lookup(obj, OFF_TO_IDX(off + toff)); 2774 if (!m) 2775 goto notinmem; 2776 tinc = size; 2777 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 2778 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 2779 if (vm_page_is_valid(m, 2780 (vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0) 2781 goto notinmem; 2782 } 2783 VM_OBJECT_RUNLOCK(obj); 2784 return 1; 2785 2786notinmem: 2787 VM_OBJECT_RUNLOCK(obj); 2788 return (0); 2789} 2790 2791/* 2792 * Set the dirty range for a buffer based on the status of the dirty 2793 * bits in the pages comprising the buffer. The range is limited 2794 * to the size of the buffer. 2795 * 2796 * Tell the VM system that the pages associated with this buffer 2797 * are clean. This is used for delayed writes where the data is 2798 * going to go to disk eventually without additional VM intevention. 2799 * 2800 * Note that while we only really need to clean through to b_bcount, we 2801 * just go ahead and clean through to b_bufsize. 2802 */ 2803static void 2804vfs_clean_pages_dirty_buf(struct buf *bp) 2805{ 2806 vm_ooffset_t foff, noff, eoff; 2807 vm_page_t m; 2808 int i; 2809 2810 if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0) 2811 return; 2812 2813 foff = bp->b_offset; 2814 KASSERT(bp->b_offset != NOOFFSET, 2815 ("vfs_clean_pages_dirty_buf: no buffer offset")); 2816 2817 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 2818 vfs_drain_busy_pages(bp); 2819 vfs_setdirty_locked_object(bp); 2820 for (i = 0; i < bp->b_npages; i++) { 2821 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 2822 eoff = noff; 2823 if (eoff > bp->b_offset + bp->b_bufsize) 2824 eoff = bp->b_offset + bp->b_bufsize; 2825 m = bp->b_pages[i]; 2826 vfs_page_set_validclean(bp, foff, m); 2827 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */ 2828 foff = noff; 2829 } 2830 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 2831} 2832 2833static void 2834vfs_setdirty_locked_object(struct buf *bp) 2835{ 2836 vm_object_t object; 2837 int i; 2838 2839 object = bp->b_bufobj->bo_object; 2840 VM_OBJECT_ASSERT_WLOCKED(object); 2841 2842 /* 2843 * We qualify the scan for modified pages on whether the 2844 * object has been flushed yet. 2845 */ 2846 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) { 2847 vm_offset_t boffset; 2848 vm_offset_t eoffset; 2849 2850 /* 2851 * test the pages to see if they have been modified directly 2852 * by users through the VM system. 2853 */ 2854 for (i = 0; i < bp->b_npages; i++) 2855 vm_page_test_dirty(bp->b_pages[i]); 2856 2857 /* 2858 * Calculate the encompassing dirty range, boffset and eoffset, 2859 * (eoffset - boffset) bytes. 2860 */ 2861 2862 for (i = 0; i < bp->b_npages; i++) { 2863 if (bp->b_pages[i]->dirty) 2864 break; 2865 } 2866 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 2867 2868 for (i = bp->b_npages - 1; i >= 0; --i) { 2869 if (bp->b_pages[i]->dirty) { 2870 break; 2871 } 2872 } 2873 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 2874 2875 /* 2876 * Fit it to the buffer. 2877 */ 2878 2879 if (eoffset > bp->b_bcount) 2880 eoffset = bp->b_bcount; 2881 2882 /* 2883 * If we have a good dirty range, merge with the existing 2884 * dirty range. 2885 */ 2886 2887 if (boffset < eoffset) { 2888 if (bp->b_dirtyoff > boffset) 2889 bp->b_dirtyoff = boffset; 2890 if (bp->b_dirtyend < eoffset) 2891 bp->b_dirtyend = eoffset; 2892 } 2893 } 2894} 2895 2896/* 2897 * Allocate the KVA mapping for an existing buffer. It handles the 2898 * cases of both B_UNMAPPED buffer, and buffer with the preallocated 2899 * KVA which is not mapped (B_KVAALLOC). 2900 */ 2901static void 2902bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags) 2903{ 2904 struct buf *scratch_bp; 2905 int bsize, maxsize, need_mapping, need_kva; 2906 off_t offset; 2907 2908 need_mapping = (bp->b_flags & B_UNMAPPED) != 0 && 2909 (gbflags & GB_UNMAPPED) == 0; 2910 need_kva = (bp->b_flags & (B_KVAALLOC | B_UNMAPPED)) == B_UNMAPPED && 2911 (gbflags & GB_KVAALLOC) != 0; 2912 if (!need_mapping && !need_kva) 2913 return; 2914 2915 BUF_CHECK_UNMAPPED(bp); 2916 2917 if (need_mapping && (bp->b_flags & B_KVAALLOC) != 0) { 2918 /* 2919 * Buffer is not mapped, but the KVA was already 2920 * reserved at the time of the instantiation. Use the 2921 * allocated space. 2922 */ 2923 bp->b_flags &= ~B_KVAALLOC; 2924 KASSERT(bp->b_kvaalloc != 0, ("kvaalloc == 0")); 2925 bp->b_kvabase = bp->b_kvaalloc; 2926 atomic_subtract_long(&unmapped_bufspace, bp->b_kvasize); 2927 goto has_addr; 2928 } 2929 2930 /* 2931 * Calculate the amount of the address space we would reserve 2932 * if the buffer was mapped. 2933 */ 2934 bsize = vn_isdisk(bp->b_vp, NULL) ? DEV_BSIZE : bp->b_bufobj->bo_bsize; 2935 offset = blkno * bsize; 2936 maxsize = size + (offset & PAGE_MASK); 2937 maxsize = imax(maxsize, bsize); 2938 2939mapping_loop: 2940 if (allocbufkva(bp, maxsize, gbflags)) { 2941 /* 2942 * Request defragmentation. getnewbuf() returns us the 2943 * allocated space by the scratch buffer KVA. 2944 */ 2945 scratch_bp = getnewbuf(bp->b_vp, 0, 0, size, maxsize, gbflags | 2946 (GB_UNMAPPED | GB_KVAALLOC)); 2947 if (scratch_bp == NULL) { 2948 if ((gbflags & GB_NOWAIT_BD) != 0) { 2949 /* 2950 * XXXKIB: defragmentation cannot 2951 * succeed, not sure what else to do. 2952 */ 2953 panic("GB_NOWAIT_BD and B_UNMAPPED %p", bp); 2954 } 2955 atomic_add_int(&mappingrestarts, 1); 2956 goto mapping_loop; 2957 } 2958 KASSERT((scratch_bp->b_flags & B_KVAALLOC) != 0, 2959 ("scratch bp !B_KVAALLOC %p", scratch_bp)); 2960 setbufkva(bp, (vm_offset_t)scratch_bp->b_kvaalloc, 2961 scratch_bp->b_kvasize, gbflags); 2962 2963 /* Get rid of the scratch buffer. */ 2964 scratch_bp->b_kvasize = 0; 2965 scratch_bp->b_flags |= B_INVAL; 2966 scratch_bp->b_flags &= ~(B_UNMAPPED | B_KVAALLOC); 2967 brelse(scratch_bp); 2968 } 2969 if (!need_mapping) 2970 return; 2971 2972has_addr: 2973 bp->b_saveaddr = bp->b_kvabase; 2974 bp->b_data = bp->b_saveaddr; /* b_offset is handled by bpmap_qenter */ 2975 bp->b_flags &= ~B_UNMAPPED; 2976 BUF_CHECK_MAPPED(bp); 2977 bpmap_qenter(bp); 2978} 2979 2980/* 2981 * getblk: 2982 * 2983 * Get a block given a specified block and offset into a file/device. 2984 * The buffers B_DONE bit will be cleared on return, making it almost 2985 * ready for an I/O initiation. B_INVAL may or may not be set on 2986 * return. The caller should clear B_INVAL prior to initiating a 2987 * READ. 2988 * 2989 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for 2990 * an existing buffer. 2991 * 2992 * For a VMIO buffer, B_CACHE is modified according to the backing VM. 2993 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set 2994 * and then cleared based on the backing VM. If the previous buffer is 2995 * non-0-sized but invalid, B_CACHE will be cleared. 2996 * 2997 * If getblk() must create a new buffer, the new buffer is returned with 2998 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which 2999 * case it is returned with B_INVAL clear and B_CACHE set based on the 3000 * backing VM. 3001 * 3002 * getblk() also forces a bwrite() for any B_DELWRI buffer whos 3003 * B_CACHE bit is clear. 3004 * 3005 * What this means, basically, is that the caller should use B_CACHE to 3006 * determine whether the buffer is fully valid or not and should clear 3007 * B_INVAL prior to issuing a read. If the caller intends to validate 3008 * the buffer by loading its data area with something, the caller needs 3009 * to clear B_INVAL. If the caller does this without issuing an I/O, 3010 * the caller should set B_CACHE ( as an optimization ), else the caller 3011 * should issue the I/O and biodone() will set B_CACHE if the I/O was 3012 * a write attempt or if it was a successfull read. If the caller 3013 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR 3014 * prior to issuing the READ. biodone() will *not* clear B_INVAL. 3015 */ 3016struct buf * 3017getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo, 3018 int flags) 3019{ 3020 struct buf *bp; 3021 struct bufobj *bo; 3022 int bsize, error, maxsize, vmio; 3023 off_t offset; 3024 3025 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size); 3026 KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3027 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3028 ASSERT_VOP_LOCKED(vp, "getblk"); 3029 if (size > MAXBSIZE) 3030 panic("getblk: size(%d) > MAXBSIZE(%d)\n", size, MAXBSIZE); 3031 if (!unmapped_buf_allowed) 3032 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3033 3034 bo = &vp->v_bufobj; 3035loop: 3036 BO_RLOCK(bo); 3037 bp = gbincore(bo, blkno); 3038 if (bp != NULL) { 3039 int lockflags; 3040 /* 3041 * Buffer is in-core. If the buffer is not busy nor managed, 3042 * it must be on a queue. 3043 */ 3044 lockflags = LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK; 3045 3046 if (flags & GB_LOCK_NOWAIT) 3047 lockflags |= LK_NOWAIT; 3048 3049 error = BUF_TIMELOCK(bp, lockflags, 3050 BO_LOCKPTR(bo), "getblk", slpflag, slptimeo); 3051 3052 /* 3053 * If we slept and got the lock we have to restart in case 3054 * the buffer changed identities. 3055 */ 3056 if (error == ENOLCK) 3057 goto loop; 3058 /* We timed out or were interrupted. */ 3059 else if (error) 3060 return (NULL); 3061 /* If recursed, assume caller knows the rules. */ 3062 else if (BUF_LOCKRECURSED(bp)) 3063 goto end; 3064 3065 /* 3066 * The buffer is locked. B_CACHE is cleared if the buffer is 3067 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set 3068 * and for a VMIO buffer B_CACHE is adjusted according to the 3069 * backing VM cache. 3070 */ 3071 if (bp->b_flags & B_INVAL) 3072 bp->b_flags &= ~B_CACHE; 3073 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0) 3074 bp->b_flags |= B_CACHE; 3075 if (bp->b_flags & B_MANAGED) 3076 MPASS(bp->b_qindex == QUEUE_NONE); 3077 else 3078 bremfree(bp); 3079 3080 /* 3081 * check for size inconsistencies for non-VMIO case. 3082 */ 3083 if (bp->b_bcount != size) { 3084 if ((bp->b_flags & B_VMIO) == 0 || 3085 (size > bp->b_kvasize)) { 3086 if (bp->b_flags & B_DELWRI) { 3087 /* 3088 * If buffer is pinned and caller does 3089 * not want sleep waiting for it to be 3090 * unpinned, bail out 3091 * */ 3092 if (bp->b_pin_count > 0) { 3093 if (flags & GB_LOCK_NOWAIT) { 3094 bqrelse(bp); 3095 return (NULL); 3096 } else { 3097 bunpin_wait(bp); 3098 } 3099 } 3100 bp->b_flags |= B_NOCACHE; 3101 bwrite(bp); 3102 } else { 3103 if (LIST_EMPTY(&bp->b_dep)) { 3104 bp->b_flags |= B_RELBUF; 3105 brelse(bp); 3106 } else { 3107 bp->b_flags |= B_NOCACHE; 3108 bwrite(bp); 3109 } 3110 } 3111 goto loop; 3112 } 3113 } 3114 3115 /* 3116 * Handle the case of unmapped buffer which should 3117 * become mapped, or the buffer for which KVA 3118 * reservation is requested. 3119 */ 3120 bp_unmapped_get_kva(bp, blkno, size, flags); 3121 3122 /* 3123 * If the size is inconsistant in the VMIO case, we can resize 3124 * the buffer. This might lead to B_CACHE getting set or 3125 * cleared. If the size has not changed, B_CACHE remains 3126 * unchanged from its previous state. 3127 */ 3128 if (bp->b_bcount != size) 3129 allocbuf(bp, size); 3130 3131 KASSERT(bp->b_offset != NOOFFSET, 3132 ("getblk: no buffer offset")); 3133 3134 /* 3135 * A buffer with B_DELWRI set and B_CACHE clear must 3136 * be committed before we can return the buffer in 3137 * order to prevent the caller from issuing a read 3138 * ( due to B_CACHE not being set ) and overwriting 3139 * it. 3140 * 3141 * Most callers, including NFS and FFS, need this to 3142 * operate properly either because they assume they 3143 * can issue a read if B_CACHE is not set, or because 3144 * ( for example ) an uncached B_DELWRI might loop due 3145 * to softupdates re-dirtying the buffer. In the latter 3146 * case, B_CACHE is set after the first write completes, 3147 * preventing further loops. 3148 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE 3149 * above while extending the buffer, we cannot allow the 3150 * buffer to remain with B_CACHE set after the write 3151 * completes or it will represent a corrupt state. To 3152 * deal with this we set B_NOCACHE to scrap the buffer 3153 * after the write. 3154 * 3155 * We might be able to do something fancy, like setting 3156 * B_CACHE in bwrite() except if B_DELWRI is already set, 3157 * so the below call doesn't set B_CACHE, but that gets real 3158 * confusing. This is much easier. 3159 */ 3160 3161 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) { 3162 bp->b_flags |= B_NOCACHE; 3163 bwrite(bp); 3164 goto loop; 3165 } 3166 bp->b_flags &= ~B_DONE; 3167 } else { 3168 /* 3169 * Buffer is not in-core, create new buffer. The buffer 3170 * returned by getnewbuf() is locked. Note that the returned 3171 * buffer is also considered valid (not marked B_INVAL). 3172 */ 3173 BO_RUNLOCK(bo); 3174 /* 3175 * If the user does not want us to create the buffer, bail out 3176 * here. 3177 */ 3178 if (flags & GB_NOCREAT) 3179 return NULL; 3180 if (numfreebuffers == 0 && TD_IS_IDLETHREAD(curthread)) 3181 return NULL; 3182 3183 bsize = vn_isdisk(vp, NULL) ? DEV_BSIZE : bo->bo_bsize; 3184 offset = blkno * bsize; 3185 vmio = vp->v_object != NULL; 3186 if (vmio) { 3187 maxsize = size + (offset & PAGE_MASK); 3188 } else { 3189 maxsize = size; 3190 /* Do not allow non-VMIO notmapped buffers. */ 3191 flags &= ~GB_UNMAPPED; 3192 } 3193 maxsize = imax(maxsize, bsize); 3194 3195 bp = getnewbuf(vp, slpflag, slptimeo, size, maxsize, flags); 3196 if (bp == NULL) { 3197 if (slpflag || slptimeo) 3198 return NULL; 3199 goto loop; 3200 } 3201 3202 /* 3203 * This code is used to make sure that a buffer is not 3204 * created while the getnewbuf routine is blocked. 3205 * This can be a problem whether the vnode is locked or not. 3206 * If the buffer is created out from under us, we have to 3207 * throw away the one we just created. 3208 * 3209 * Note: this must occur before we associate the buffer 3210 * with the vp especially considering limitations in 3211 * the splay tree implementation when dealing with duplicate 3212 * lblkno's. 3213 */ 3214 BO_LOCK(bo); 3215 if (gbincore(bo, blkno)) { 3216 BO_UNLOCK(bo); 3217 bp->b_flags |= B_INVAL; 3218 brelse(bp); 3219 goto loop; 3220 } 3221 3222 /* 3223 * Insert the buffer into the hash, so that it can 3224 * be found by incore. 3225 */ 3226 bp->b_blkno = bp->b_lblkno = blkno; 3227 bp->b_offset = offset; 3228 bgetvp(vp, bp); 3229 BO_UNLOCK(bo); 3230 3231 /* 3232 * set B_VMIO bit. allocbuf() the buffer bigger. Since the 3233 * buffer size starts out as 0, B_CACHE will be set by 3234 * allocbuf() for the VMIO case prior to it testing the 3235 * backing store for validity. 3236 */ 3237 3238 if (vmio) { 3239 bp->b_flags |= B_VMIO; 3240 KASSERT(vp->v_object == bp->b_bufobj->bo_object, 3241 ("ARGH! different b_bufobj->bo_object %p %p %p\n", 3242 bp, vp->v_object, bp->b_bufobj->bo_object)); 3243 } else { 3244 bp->b_flags &= ~B_VMIO; 3245 KASSERT(bp->b_bufobj->bo_object == NULL, 3246 ("ARGH! has b_bufobj->bo_object %p %p\n", 3247 bp, bp->b_bufobj->bo_object)); 3248 BUF_CHECK_MAPPED(bp); 3249 } 3250 3251 allocbuf(bp, size); 3252 bp->b_flags &= ~B_DONE; 3253 } 3254 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp); 3255 BUF_ASSERT_HELD(bp); 3256end: 3257 KASSERT(bp->b_bufobj == bo, 3258 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo)); 3259 return (bp); 3260} 3261 3262/* 3263 * Get an empty, disassociated buffer of given size. The buffer is initially 3264 * set to B_INVAL. 3265 */ 3266struct buf * 3267geteblk(int size, int flags) 3268{ 3269 struct buf *bp; 3270 int maxsize; 3271 3272 maxsize = (size + BKVAMASK) & ~BKVAMASK; 3273 while ((bp = getnewbuf(NULL, 0, 0, size, maxsize, flags)) == NULL) { 3274 if ((flags & GB_NOWAIT_BD) && 3275 (curthread->td_pflags & TDP_BUFNEED) != 0) 3276 return (NULL); 3277 } 3278 allocbuf(bp, size); 3279 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 3280 BUF_ASSERT_HELD(bp); 3281 return (bp); 3282} 3283 3284 3285/* 3286 * This code constitutes the buffer memory from either anonymous system 3287 * memory (in the case of non-VMIO operations) or from an associated 3288 * VM object (in the case of VMIO operations). This code is able to 3289 * resize a buffer up or down. 3290 * 3291 * Note that this code is tricky, and has many complications to resolve 3292 * deadlock or inconsistant data situations. Tread lightly!!! 3293 * There are B_CACHE and B_DELWRI interactions that must be dealt with by 3294 * the caller. Calling this code willy nilly can result in the loss of data. 3295 * 3296 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with 3297 * B_CACHE for the non-VMIO case. 3298 */ 3299 3300int 3301allocbuf(struct buf *bp, int size) 3302{ 3303 int newbsize, mbsize; 3304 int i; 3305 3306 BUF_ASSERT_HELD(bp); 3307 3308 if (bp->b_kvasize < size) 3309 panic("allocbuf: buffer too small"); 3310 3311 if ((bp->b_flags & B_VMIO) == 0) { 3312 caddr_t origbuf; 3313 int origbufsize; 3314 /* 3315 * Just get anonymous memory from the kernel. Don't 3316 * mess with B_CACHE. 3317 */ 3318 mbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); 3319 if (bp->b_flags & B_MALLOC) 3320 newbsize = mbsize; 3321 else 3322 newbsize = round_page(size); 3323 3324 if (newbsize < bp->b_bufsize) { 3325 /* 3326 * malloced buffers are not shrunk 3327 */ 3328 if (bp->b_flags & B_MALLOC) { 3329 if (newbsize) { 3330 bp->b_bcount = size; 3331 } else { 3332 free(bp->b_data, M_BIOBUF); 3333 if (bp->b_bufsize) { 3334 atomic_subtract_long( 3335 &bufmallocspace, 3336 bp->b_bufsize); 3337 bufspacewakeup(); 3338 bp->b_bufsize = 0; 3339 } 3340 bp->b_saveaddr = bp->b_kvabase; 3341 bp->b_data = bp->b_saveaddr; 3342 bp->b_bcount = 0; 3343 bp->b_flags &= ~B_MALLOC; 3344 } 3345 return 1; 3346 } 3347 vm_hold_free_pages(bp, newbsize); 3348 } else if (newbsize > bp->b_bufsize) { 3349 /* 3350 * We only use malloced memory on the first allocation. 3351 * and revert to page-allocated memory when the buffer 3352 * grows. 3353 */ 3354 /* 3355 * There is a potential smp race here that could lead 3356 * to bufmallocspace slightly passing the max. It 3357 * is probably extremely rare and not worth worrying 3358 * over. 3359 */ 3360 if ( (bufmallocspace < maxbufmallocspace) && 3361 (bp->b_bufsize == 0) && 3362 (mbsize <= PAGE_SIZE/2)) { 3363 3364 bp->b_data = malloc(mbsize, M_BIOBUF, M_WAITOK); 3365 bp->b_bufsize = mbsize; 3366 bp->b_bcount = size; 3367 bp->b_flags |= B_MALLOC; 3368 atomic_add_long(&bufmallocspace, mbsize); 3369 return 1; 3370 } 3371 origbuf = NULL; 3372 origbufsize = 0; 3373 /* 3374 * If the buffer is growing on its other-than-first allocation, 3375 * then we revert to the page-allocation scheme. 3376 */ 3377 if (bp->b_flags & B_MALLOC) { 3378 origbuf = bp->b_data; 3379 origbufsize = bp->b_bufsize; 3380 bp->b_data = bp->b_kvabase; 3381 if (bp->b_bufsize) { 3382 atomic_subtract_long(&bufmallocspace, 3383 bp->b_bufsize); 3384 bufspacewakeup(); 3385 bp->b_bufsize = 0; 3386 } 3387 bp->b_flags &= ~B_MALLOC; 3388 newbsize = round_page(newbsize); 3389 } 3390 vm_hold_load_pages( 3391 bp, 3392 (vm_offset_t) bp->b_data + bp->b_bufsize, 3393 (vm_offset_t) bp->b_data + newbsize); 3394 if (origbuf) { 3395 bcopy(origbuf, bp->b_data, origbufsize); 3396 free(origbuf, M_BIOBUF); 3397 } 3398 } 3399 } else { 3400 int desiredpages; 3401 3402 newbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); 3403 desiredpages = (size == 0) ? 0 : 3404 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 3405 3406 if (bp->b_flags & B_MALLOC) 3407 panic("allocbuf: VMIO buffer can't be malloced"); 3408 /* 3409 * Set B_CACHE initially if buffer is 0 length or will become 3410 * 0-length. 3411 */ 3412 if (size == 0 || bp->b_bufsize == 0) 3413 bp->b_flags |= B_CACHE; 3414 3415 if (newbsize < bp->b_bufsize) { 3416 /* 3417 * DEV_BSIZE aligned new buffer size is less then the 3418 * DEV_BSIZE aligned existing buffer size. Figure out 3419 * if we have to remove any pages. 3420 */ 3421 if (desiredpages < bp->b_npages) { 3422 vm_page_t m; 3423 3424 if ((bp->b_flags & B_UNMAPPED) == 0) { 3425 BUF_CHECK_MAPPED(bp); 3426 pmap_qremove((vm_offset_t)trunc_page( 3427 (vm_offset_t)bp->b_data) + 3428 (desiredpages << PAGE_SHIFT), 3429 (bp->b_npages - desiredpages)); 3430 } else 3431 BUF_CHECK_UNMAPPED(bp); 3432 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 3433 for (i = desiredpages; i < bp->b_npages; i++) { 3434 /* 3435 * the page is not freed here -- it 3436 * is the responsibility of 3437 * vnode_pager_setsize 3438 */ 3439 m = bp->b_pages[i]; 3440 KASSERT(m != bogus_page, 3441 ("allocbuf: bogus page found")); 3442 while (vm_page_sleep_if_busy(m, 3443 "biodep")) 3444 continue; 3445 3446 bp->b_pages[i] = NULL; 3447 vm_page_lock(m); 3448 vm_page_unwire(m, 0); 3449 vm_page_unlock(m); 3450 } 3451 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 3452 bp->b_npages = desiredpages; 3453 } 3454 } else if (size > bp->b_bcount) { 3455 /* 3456 * We are growing the buffer, possibly in a 3457 * byte-granular fashion. 3458 */ 3459 vm_object_t obj; 3460 vm_offset_t toff; 3461 vm_offset_t tinc; 3462 3463 /* 3464 * Step 1, bring in the VM pages from the object, 3465 * allocating them if necessary. We must clear 3466 * B_CACHE if these pages are not valid for the 3467 * range covered by the buffer. 3468 */ 3469 3470 obj = bp->b_bufobj->bo_object; 3471 3472 VM_OBJECT_WLOCK(obj); 3473 while (bp->b_npages < desiredpages) { 3474 vm_page_t m; 3475 3476 /* 3477 * We must allocate system pages since blocking 3478 * here could interfere with paging I/O, no 3479 * matter which process we are. 3480 * 3481 * Only exclusive busy can be tested here. 3482 * Blocking on shared busy might lead to 3483 * deadlocks once allocbuf() is called after 3484 * pages are vfs_busy_pages(). 3485 */ 3486 m = vm_page_grab(obj, OFF_TO_IDX(bp->b_offset) + 3487 bp->b_npages, VM_ALLOC_NOBUSY | 3488 VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | 3489 VM_ALLOC_IGN_SBUSY | 3490 VM_ALLOC_COUNT(desiredpages - bp->b_npages)); 3491 if (m->valid == 0) 3492 bp->b_flags &= ~B_CACHE; 3493 bp->b_pages[bp->b_npages] = m; 3494 ++bp->b_npages; 3495 } 3496 3497 /* 3498 * Step 2. We've loaded the pages into the buffer, 3499 * we have to figure out if we can still have B_CACHE 3500 * set. Note that B_CACHE is set according to the 3501 * byte-granular range ( bcount and size ), new the 3502 * aligned range ( newbsize ). 3503 * 3504 * The VM test is against m->valid, which is DEV_BSIZE 3505 * aligned. Needless to say, the validity of the data 3506 * needs to also be DEV_BSIZE aligned. Note that this 3507 * fails with NFS if the server or some other client 3508 * extends the file's EOF. If our buffer is resized, 3509 * B_CACHE may remain set! XXX 3510 */ 3511 3512 toff = bp->b_bcount; 3513 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK); 3514 3515 while ((bp->b_flags & B_CACHE) && toff < size) { 3516 vm_pindex_t pi; 3517 3518 if (tinc > (size - toff)) 3519 tinc = size - toff; 3520 3521 pi = ((bp->b_offset & PAGE_MASK) + toff) >> 3522 PAGE_SHIFT; 3523 3524 vfs_buf_test_cache( 3525 bp, 3526 bp->b_offset, 3527 toff, 3528 tinc, 3529 bp->b_pages[pi] 3530 ); 3531 toff += tinc; 3532 tinc = PAGE_SIZE; 3533 } 3534 VM_OBJECT_WUNLOCK(obj); 3535 3536 /* 3537 * Step 3, fixup the KVM pmap. 3538 */ 3539 if ((bp->b_flags & B_UNMAPPED) == 0) 3540 bpmap_qenter(bp); 3541 else 3542 BUF_CHECK_UNMAPPED(bp); 3543 } 3544 } 3545 if (newbsize < bp->b_bufsize) 3546 bufspacewakeup(); 3547 bp->b_bufsize = newbsize; /* actual buffer allocation */ 3548 bp->b_bcount = size; /* requested buffer size */ 3549 return 1; 3550} 3551 3552extern int inflight_transient_maps; 3553 3554void 3555biodone(struct bio *bp) 3556{ 3557 struct mtx *mtxp; 3558 void (*done)(struct bio *); 3559 vm_offset_t start, end; 3560 int transient; 3561 3562 if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { 3563 start = trunc_page((vm_offset_t)bp->bio_data); 3564 end = round_page((vm_offset_t)bp->bio_data + bp->bio_length); 3565 transient = 1; 3566 } else { 3567 transient = 0; 3568 start = end = 0; 3569 } 3570 done = bp->bio_done; 3571 if (done == NULL) { 3572 mtxp = mtx_pool_find(mtxpool_sleep, bp); 3573 mtx_lock(mtxp); 3574 bp->bio_flags |= BIO_DONE; 3575 wakeup(bp); 3576 mtx_unlock(mtxp); 3577 } else { 3578 bp->bio_flags |= BIO_DONE; 3579 done(bp); 3580 } 3581 if (transient) { 3582 pmap_qremove(start, OFF_TO_IDX(end - start)); 3583 vmem_free(transient_arena, start, end - start); 3584 atomic_add_int(&inflight_transient_maps, -1); 3585 } 3586} 3587 3588/* 3589 * Wait for a BIO to finish. 3590 */ 3591int 3592biowait(struct bio *bp, const char *wchan) 3593{ 3594 struct mtx *mtxp; 3595 3596 mtxp = mtx_pool_find(mtxpool_sleep, bp); 3597 mtx_lock(mtxp); 3598 while ((bp->bio_flags & BIO_DONE) == 0) 3599 msleep(bp, mtxp, PRIBIO, wchan, 0); 3600 mtx_unlock(mtxp); 3601 if (bp->bio_error != 0) 3602 return (bp->bio_error); 3603 if (!(bp->bio_flags & BIO_ERROR)) 3604 return (0); 3605 return (EIO); 3606} 3607 3608void 3609biofinish(struct bio *bp, struct devstat *stat, int error) 3610{ 3611 3612 if (error) { 3613 bp->bio_error = error; 3614 bp->bio_flags |= BIO_ERROR; 3615 } 3616 if (stat != NULL) 3617 devstat_end_transaction_bio(stat, bp); 3618 biodone(bp); 3619} 3620 3621/* 3622 * bufwait: 3623 * 3624 * Wait for buffer I/O completion, returning error status. The buffer 3625 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR 3626 * error and cleared. 3627 */ 3628int 3629bufwait(struct buf *bp) 3630{ 3631 if (bp->b_iocmd == BIO_READ) 3632 bwait(bp, PRIBIO, "biord"); 3633 else 3634 bwait(bp, PRIBIO, "biowr"); 3635 if (bp->b_flags & B_EINTR) { 3636 bp->b_flags &= ~B_EINTR; 3637 return (EINTR); 3638 } 3639 if (bp->b_ioflags & BIO_ERROR) { 3640 return (bp->b_error ? bp->b_error : EIO); 3641 } else { 3642 return (0); 3643 } 3644} 3645 3646 /* 3647 * Call back function from struct bio back up to struct buf. 3648 */ 3649static void 3650bufdonebio(struct bio *bip) 3651{ 3652 struct buf *bp; 3653 3654 bp = bip->bio_caller2; 3655 bp->b_resid = bp->b_bcount - bip->bio_completed; 3656 bp->b_resid = bip->bio_resid; /* XXX: remove */ 3657 bp->b_ioflags = bip->bio_flags; 3658 bp->b_error = bip->bio_error; 3659 if (bp->b_error) 3660 bp->b_ioflags |= BIO_ERROR; 3661 bufdone(bp); 3662 g_destroy_bio(bip); 3663} 3664 3665void 3666dev_strategy(struct cdev *dev, struct buf *bp) 3667{ 3668 struct cdevsw *csw; 3669 int ref; 3670 3671 KASSERT(dev->si_refcount > 0, 3672 ("dev_strategy on un-referenced struct cdev *(%s) %p", 3673 devtoname(dev), dev)); 3674 3675 csw = dev_refthread(dev, &ref); 3676 dev_strategy_csw(dev, csw, bp); 3677 dev_relthread(dev, ref); 3678} 3679 3680void 3681dev_strategy_csw(struct cdev *dev, struct cdevsw *csw, struct buf *bp) 3682{ 3683 struct bio *bip; 3684 3685 KASSERT(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE, 3686 ("b_iocmd botch")); 3687 KASSERT(((dev->si_flags & SI_ETERNAL) != 0 && csw != NULL) || 3688 dev->si_threadcount > 0, 3689 ("dev_strategy_csw threadcount cdev *(%s) %p", devtoname(dev), 3690 dev)); 3691 if (csw == NULL) { 3692 bp->b_error = ENXIO; 3693 bp->b_ioflags = BIO_ERROR; 3694 bufdone(bp); 3695 return; 3696 } 3697 for (;;) { 3698 bip = g_new_bio(); 3699 if (bip != NULL) 3700 break; 3701 /* Try again later */ 3702 tsleep(&bp, PRIBIO, "dev_strat", hz/10); 3703 } 3704 bip->bio_cmd = bp->b_iocmd; 3705 bip->bio_offset = bp->b_iooffset; 3706 bip->bio_length = bp->b_bcount; 3707 bip->bio_bcount = bp->b_bcount; /* XXX: remove */ 3708 bdata2bio(bp, bip); 3709 bip->bio_done = bufdonebio; 3710 bip->bio_caller2 = bp; 3711 bip->bio_dev = dev; 3712 (*csw->d_strategy)(bip); 3713} 3714 3715/* 3716 * bufdone: 3717 * 3718 * Finish I/O on a buffer, optionally calling a completion function. 3719 * This is usually called from an interrupt so process blocking is 3720 * not allowed. 3721 * 3722 * biodone is also responsible for setting B_CACHE in a B_VMIO bp. 3723 * In a non-VMIO bp, B_CACHE will be set on the next getblk() 3724 * assuming B_INVAL is clear. 3725 * 3726 * For the VMIO case, we set B_CACHE if the op was a read and no 3727 * read error occured, or if the op was a write. B_CACHE is never 3728 * set if the buffer is invalid or otherwise uncacheable. 3729 * 3730 * biodone does not mess with B_INVAL, allowing the I/O routine or the 3731 * initiator to leave B_INVAL set to brelse the buffer out of existance 3732 * in the biodone routine. 3733 */ 3734void 3735bufdone(struct buf *bp) 3736{ 3737 struct bufobj *dropobj; 3738 void (*biodone)(struct buf *); 3739 3740 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 3741 dropobj = NULL; 3742 3743 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp)); 3744 BUF_ASSERT_HELD(bp); 3745 3746 runningbufwakeup(bp); 3747 if (bp->b_iocmd == BIO_WRITE) 3748 dropobj = bp->b_bufobj; 3749 /* call optional completion function if requested */ 3750 if (bp->b_iodone != NULL) { 3751 biodone = bp->b_iodone; 3752 bp->b_iodone = NULL; 3753 (*biodone) (bp); 3754 if (dropobj) 3755 bufobj_wdrop(dropobj); 3756 return; 3757 } 3758 3759 bufdone_finish(bp); 3760 3761 if (dropobj) 3762 bufobj_wdrop(dropobj); 3763} 3764 3765void 3766bufdone_finish(struct buf *bp) 3767{ 3768 BUF_ASSERT_HELD(bp); 3769 3770 if (!LIST_EMPTY(&bp->b_dep)) 3771 buf_complete(bp); 3772 3773 if (bp->b_flags & B_VMIO) { 3774 vm_ooffset_t foff; 3775 vm_page_t m; 3776 vm_object_t obj; 3777 struct vnode *vp; 3778 int bogus, i, iosize; 3779 3780 obj = bp->b_bufobj->bo_object; 3781 KASSERT(obj->paging_in_progress >= bp->b_npages, 3782 ("biodone_finish: paging in progress(%d) < b_npages(%d)", 3783 obj->paging_in_progress, bp->b_npages)); 3784 3785 vp = bp->b_vp; 3786 KASSERT(vp->v_holdcnt > 0, 3787 ("biodone_finish: vnode %p has zero hold count", vp)); 3788 KASSERT(vp->v_object != NULL, 3789 ("biodone_finish: vnode %p has no vm_object", vp)); 3790 3791 foff = bp->b_offset; 3792 KASSERT(bp->b_offset != NOOFFSET, 3793 ("biodone_finish: bp %p has no buffer offset", bp)); 3794 3795 /* 3796 * Set B_CACHE if the op was a normal read and no error 3797 * occured. B_CACHE is set for writes in the b*write() 3798 * routines. 3799 */ 3800 iosize = bp->b_bcount - bp->b_resid; 3801 if (bp->b_iocmd == BIO_READ && 3802 !(bp->b_flags & (B_INVAL|B_NOCACHE)) && 3803 !(bp->b_ioflags & BIO_ERROR)) { 3804 bp->b_flags |= B_CACHE; 3805 } 3806 bogus = 0; 3807 VM_OBJECT_WLOCK(obj); 3808 for (i = 0; i < bp->b_npages; i++) { 3809 int bogusflag = 0; 3810 int resid; 3811 3812 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff; 3813 if (resid > iosize) 3814 resid = iosize; 3815 3816 /* 3817 * cleanup bogus pages, restoring the originals 3818 */ 3819 m = bp->b_pages[i]; 3820 if (m == bogus_page) { 3821 bogus = bogusflag = 1; 3822 m = vm_page_lookup(obj, OFF_TO_IDX(foff)); 3823 if (m == NULL) 3824 panic("biodone: page disappeared!"); 3825 bp->b_pages[i] = m; 3826 } 3827 KASSERT(OFF_TO_IDX(foff) == m->pindex, 3828 ("biodone_finish: foff(%jd)/pindex(%ju) mismatch", 3829 (intmax_t)foff, (uintmax_t)m->pindex)); 3830 3831 /* 3832 * In the write case, the valid and clean bits are 3833 * already changed correctly ( see bdwrite() ), so we 3834 * only need to do this here in the read case. 3835 */ 3836 if ((bp->b_iocmd == BIO_READ) && !bogusflag && resid > 0) { 3837 KASSERT((m->dirty & vm_page_bits(foff & 3838 PAGE_MASK, resid)) == 0, ("bufdone_finish:" 3839 " page %p has unexpected dirty bits", m)); 3840 vfs_page_set_valid(bp, foff, m); 3841 } 3842 3843 vm_page_sunbusy(m); 3844 vm_object_pip_subtract(obj, 1); 3845 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3846 iosize -= resid; 3847 } 3848 vm_object_pip_wakeupn(obj, 0); 3849 VM_OBJECT_WUNLOCK(obj); 3850 if (bogus && (bp->b_flags & B_UNMAPPED) == 0) { 3851 BUF_CHECK_MAPPED(bp); 3852 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 3853 bp->b_pages, bp->b_npages); 3854 } 3855 } 3856 3857 /* 3858 * For asynchronous completions, release the buffer now. The brelse 3859 * will do a wakeup there if necessary - so no need to do a wakeup 3860 * here in the async case. The sync case always needs to do a wakeup. 3861 */ 3862 3863 if (bp->b_flags & B_ASYNC) { 3864 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || (bp->b_ioflags & BIO_ERROR)) 3865 brelse(bp); 3866 else 3867 bqrelse(bp); 3868 } else 3869 bdone(bp); 3870} 3871 3872/* 3873 * This routine is called in lieu of iodone in the case of 3874 * incomplete I/O. This keeps the busy status for pages 3875 * consistant. 3876 */ 3877void 3878vfs_unbusy_pages(struct buf *bp) 3879{ 3880 int i; 3881 vm_object_t obj; 3882 vm_page_t m; 3883 3884 runningbufwakeup(bp); 3885 if (!(bp->b_flags & B_VMIO)) 3886 return; 3887 3888 obj = bp->b_bufobj->bo_object; 3889 VM_OBJECT_WLOCK(obj); 3890 for (i = 0; i < bp->b_npages; i++) { 3891 m = bp->b_pages[i]; 3892 if (m == bogus_page) { 3893 m = vm_page_lookup(obj, OFF_TO_IDX(bp->b_offset) + i); 3894 if (!m) 3895 panic("vfs_unbusy_pages: page missing\n"); 3896 bp->b_pages[i] = m; 3897 if ((bp->b_flags & B_UNMAPPED) == 0) { 3898 BUF_CHECK_MAPPED(bp); 3899 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 3900 bp->b_pages, bp->b_npages); 3901 } else 3902 BUF_CHECK_UNMAPPED(bp); 3903 } 3904 vm_object_pip_subtract(obj, 1); 3905 vm_page_sunbusy(m); 3906 } 3907 vm_object_pip_wakeupn(obj, 0); 3908 VM_OBJECT_WUNLOCK(obj); 3909} 3910 3911/* 3912 * vfs_page_set_valid: 3913 * 3914 * Set the valid bits in a page based on the supplied offset. The 3915 * range is restricted to the buffer's size. 3916 * 3917 * This routine is typically called after a read completes. 3918 */ 3919static void 3920vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m) 3921{ 3922 vm_ooffset_t eoff; 3923 3924 /* 3925 * Compute the end offset, eoff, such that [off, eoff) does not span a 3926 * page boundary and eoff is not greater than the end of the buffer. 3927 * The end of the buffer, in this case, is our file EOF, not the 3928 * allocation size of the buffer. 3929 */ 3930 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK; 3931 if (eoff > bp->b_offset + bp->b_bcount) 3932 eoff = bp->b_offset + bp->b_bcount; 3933 3934 /* 3935 * Set valid range. This is typically the entire buffer and thus the 3936 * entire page. 3937 */ 3938 if (eoff > off) 3939 vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off); 3940} 3941 3942/* 3943 * vfs_page_set_validclean: 3944 * 3945 * Set the valid bits and clear the dirty bits in a page based on the 3946 * supplied offset. The range is restricted to the buffer's size. 3947 */ 3948static void 3949vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m) 3950{ 3951 vm_ooffset_t soff, eoff; 3952 3953 /* 3954 * Start and end offsets in buffer. eoff - soff may not cross a 3955 * page boundry or cross the end of the buffer. The end of the 3956 * buffer, in this case, is our file EOF, not the allocation size 3957 * of the buffer. 3958 */ 3959 soff = off; 3960 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3961 if (eoff > bp->b_offset + bp->b_bcount) 3962 eoff = bp->b_offset + bp->b_bcount; 3963 3964 /* 3965 * Set valid range. This is typically the entire buffer and thus the 3966 * entire page. 3967 */ 3968 if (eoff > soff) { 3969 vm_page_set_validclean( 3970 m, 3971 (vm_offset_t) (soff & PAGE_MASK), 3972 (vm_offset_t) (eoff - soff) 3973 ); 3974 } 3975} 3976 3977/* 3978 * Ensure that all buffer pages are not exclusive busied. If any page is 3979 * exclusive busy, drain it. 3980 */ 3981void 3982vfs_drain_busy_pages(struct buf *bp) 3983{ 3984 vm_page_t m; 3985 int i, last_busied; 3986 3987 VM_OBJECT_ASSERT_WLOCKED(bp->b_bufobj->bo_object); 3988 last_busied = 0; 3989 for (i = 0; i < bp->b_npages; i++) { 3990 m = bp->b_pages[i]; 3991 if (vm_page_xbusied(m)) { 3992 for (; last_busied < i; last_busied++) 3993 vm_page_sbusy(bp->b_pages[last_busied]); 3994 while (vm_page_xbusied(m)) { 3995 vm_page_lock(m); 3996 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 3997 vm_page_busy_sleep(m, "vbpage"); 3998 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 3999 } 4000 } 4001 } 4002 for (i = 0; i < last_busied; i++) 4003 vm_page_sunbusy(bp->b_pages[i]); 4004} 4005 4006/* 4007 * This routine is called before a device strategy routine. 4008 * It is used to tell the VM system that paging I/O is in 4009 * progress, and treat the pages associated with the buffer 4010 * almost as being exclusive busy. Also the object paging_in_progress 4011 * flag is handled to make sure that the object doesn't become 4012 * inconsistant. 4013 * 4014 * Since I/O has not been initiated yet, certain buffer flags 4015 * such as BIO_ERROR or B_INVAL may be in an inconsistant state 4016 * and should be ignored. 4017 */ 4018void 4019vfs_busy_pages(struct buf *bp, int clear_modify) 4020{ 4021 int i, bogus; 4022 vm_object_t obj; 4023 vm_ooffset_t foff; 4024 vm_page_t m; 4025 4026 if (!(bp->b_flags & B_VMIO)) 4027 return; 4028 4029 obj = bp->b_bufobj->bo_object; 4030 foff = bp->b_offset; 4031 KASSERT(bp->b_offset != NOOFFSET, 4032 ("vfs_busy_pages: no buffer offset")); 4033 VM_OBJECT_WLOCK(obj); 4034 vfs_drain_busy_pages(bp); 4035 if (bp->b_bufsize != 0) 4036 vfs_setdirty_locked_object(bp); 4037 bogus = 0; 4038 for (i = 0; i < bp->b_npages; i++) { 4039 m = bp->b_pages[i]; 4040 4041 if ((bp->b_flags & B_CLUSTER) == 0) { 4042 vm_object_pip_add(obj, 1); 4043 vm_page_sbusy(m); 4044 } 4045 /* 4046 * When readying a buffer for a read ( i.e 4047 * clear_modify == 0 ), it is important to do 4048 * bogus_page replacement for valid pages in 4049 * partially instantiated buffers. Partially 4050 * instantiated buffers can, in turn, occur when 4051 * reconstituting a buffer from its VM backing store 4052 * base. We only have to do this if B_CACHE is 4053 * clear ( which causes the I/O to occur in the 4054 * first place ). The replacement prevents the read 4055 * I/O from overwriting potentially dirty VM-backed 4056 * pages. XXX bogus page replacement is, uh, bogus. 4057 * It may not work properly with small-block devices. 4058 * We need to find a better way. 4059 */ 4060 if (clear_modify) { 4061 pmap_remove_write(m); 4062 vfs_page_set_validclean(bp, foff, m); 4063 } else if (m->valid == VM_PAGE_BITS_ALL && 4064 (bp->b_flags & B_CACHE) == 0) { 4065 bp->b_pages[i] = bogus_page; 4066 bogus++; 4067 } 4068 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4069 } 4070 VM_OBJECT_WUNLOCK(obj); 4071 if (bogus && (bp->b_flags & B_UNMAPPED) == 0) { 4072 BUF_CHECK_MAPPED(bp); 4073 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4074 bp->b_pages, bp->b_npages); 4075 } 4076} 4077 4078/* 4079 * vfs_bio_set_valid: 4080 * 4081 * Set the range within the buffer to valid. The range is 4082 * relative to the beginning of the buffer, b_offset. Note that 4083 * b_offset itself may be offset from the beginning of the first 4084 * page. 4085 */ 4086void 4087vfs_bio_set_valid(struct buf *bp, int base, int size) 4088{ 4089 int i, n; 4090 vm_page_t m; 4091 4092 if (!(bp->b_flags & B_VMIO)) 4093 return; 4094 4095 /* 4096 * Fixup base to be relative to beginning of first page. 4097 * Set initial n to be the maximum number of bytes in the 4098 * first page that can be validated. 4099 */ 4100 base += (bp->b_offset & PAGE_MASK); 4101 n = PAGE_SIZE - (base & PAGE_MASK); 4102 4103 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 4104 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4105 m = bp->b_pages[i]; 4106 if (n > size) 4107 n = size; 4108 vm_page_set_valid_range(m, base & PAGE_MASK, n); 4109 base += n; 4110 size -= n; 4111 n = PAGE_SIZE; 4112 } 4113 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 4114} 4115 4116/* 4117 * vfs_bio_clrbuf: 4118 * 4119 * If the specified buffer is a non-VMIO buffer, clear the entire 4120 * buffer. If the specified buffer is a VMIO buffer, clear and 4121 * validate only the previously invalid portions of the buffer. 4122 * This routine essentially fakes an I/O, so we need to clear 4123 * BIO_ERROR and B_INVAL. 4124 * 4125 * Note that while we only theoretically need to clear through b_bcount, 4126 * we go ahead and clear through b_bufsize. 4127 */ 4128void 4129vfs_bio_clrbuf(struct buf *bp) 4130{ 4131 int i, j, mask, sa, ea, slide; 4132 4133 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) { 4134 clrbuf(bp); 4135 return; 4136 } 4137 bp->b_flags &= ~B_INVAL; 4138 bp->b_ioflags &= ~BIO_ERROR; 4139 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 4140 if ((bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE) && 4141 (bp->b_offset & PAGE_MASK) == 0) { 4142 if (bp->b_pages[0] == bogus_page) 4143 goto unlock; 4144 mask = (1 << (bp->b_bufsize / DEV_BSIZE)) - 1; 4145 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[0]->object); 4146 if ((bp->b_pages[0]->valid & mask) == mask) 4147 goto unlock; 4148 if ((bp->b_pages[0]->valid & mask) == 0) { 4149 pmap_zero_page_area(bp->b_pages[0], 0, bp->b_bufsize); 4150 bp->b_pages[0]->valid |= mask; 4151 goto unlock; 4152 } 4153 } 4154 sa = bp->b_offset & PAGE_MASK; 4155 slide = 0; 4156 for (i = 0; i < bp->b_npages; i++, sa = 0) { 4157 slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize); 4158 ea = slide & PAGE_MASK; 4159 if (ea == 0) 4160 ea = PAGE_SIZE; 4161 if (bp->b_pages[i] == bogus_page) 4162 continue; 4163 j = sa / DEV_BSIZE; 4164 mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j; 4165 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[i]->object); 4166 if ((bp->b_pages[i]->valid & mask) == mask) 4167 continue; 4168 if ((bp->b_pages[i]->valid & mask) == 0) 4169 pmap_zero_page_area(bp->b_pages[i], sa, ea - sa); 4170 else { 4171 for (; sa < ea; sa += DEV_BSIZE, j++) { 4172 if ((bp->b_pages[i]->valid & (1 << j)) == 0) { 4173 pmap_zero_page_area(bp->b_pages[i], 4174 sa, DEV_BSIZE); 4175 } 4176 } 4177 } 4178 bp->b_pages[i]->valid |= mask; 4179 } 4180unlock: 4181 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 4182 bp->b_resid = 0; 4183} 4184 4185void 4186vfs_bio_bzero_buf(struct buf *bp, int base, int size) 4187{ 4188 vm_page_t m; 4189 int i, n; 4190 4191 if ((bp->b_flags & B_UNMAPPED) == 0) { 4192 BUF_CHECK_MAPPED(bp); 4193 bzero(bp->b_data + base, size); 4194 } else { 4195 BUF_CHECK_UNMAPPED(bp); 4196 n = PAGE_SIZE - (base & PAGE_MASK); 4197 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4198 m = bp->b_pages[i]; 4199 if (n > size) 4200 n = size; 4201 pmap_zero_page_area(m, base & PAGE_MASK, n); 4202 base += n; 4203 size -= n; 4204 n = PAGE_SIZE; 4205 } 4206 } 4207} 4208 4209/* 4210 * vm_hold_load_pages and vm_hold_free_pages get pages into 4211 * a buffers address space. The pages are anonymous and are 4212 * not associated with a file object. 4213 */ 4214static void 4215vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to) 4216{ 4217 vm_offset_t pg; 4218 vm_page_t p; 4219 int index; 4220 4221 BUF_CHECK_MAPPED(bp); 4222 4223 to = round_page(to); 4224 from = round_page(from); 4225 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 4226 4227 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 4228tryagain: 4229 /* 4230 * note: must allocate system pages since blocking here 4231 * could interfere with paging I/O, no matter which 4232 * process we are. 4233 */ 4234 p = vm_page_alloc(NULL, 0, VM_ALLOC_SYSTEM | VM_ALLOC_NOOBJ | 4235 VM_ALLOC_WIRED | VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT)); 4236 if (p == NULL) { 4237 VM_WAIT; 4238 goto tryagain; 4239 } 4240 pmap_qenter(pg, &p, 1); 4241 bp->b_pages[index] = p; 4242 } 4243 bp->b_npages = index; 4244} 4245 4246/* Return pages associated with this buf to the vm system */ 4247static void 4248vm_hold_free_pages(struct buf *bp, int newbsize) 4249{ 4250 vm_offset_t from; 4251 vm_page_t p; 4252 int index, newnpages; 4253 4254 BUF_CHECK_MAPPED(bp); 4255 4256 from = round_page((vm_offset_t)bp->b_data + newbsize); 4257 newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 4258 if (bp->b_npages > newnpages) 4259 pmap_qremove(from, bp->b_npages - newnpages); 4260 for (index = newnpages; index < bp->b_npages; index++) { 4261 p = bp->b_pages[index]; 4262 bp->b_pages[index] = NULL; 4263 if (vm_page_sbusied(p)) 4264 printf("vm_hold_free_pages: blkno: %jd, lblkno: %jd\n", 4265 (intmax_t)bp->b_blkno, (intmax_t)bp->b_lblkno); 4266 p->wire_count--; 4267 vm_page_free(p); 4268 atomic_subtract_int(&cnt.v_wire_count, 1); 4269 } 4270 bp->b_npages = newnpages; 4271} 4272 4273/* 4274 * Map an IO request into kernel virtual address space. 4275 * 4276 * All requests are (re)mapped into kernel VA space. 4277 * Notice that we use b_bufsize for the size of the buffer 4278 * to be mapped. b_bcount might be modified by the driver. 4279 * 4280 * Note that even if the caller determines that the address space should 4281 * be valid, a race or a smaller-file mapped into a larger space may 4282 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST 4283 * check the return value. 4284 */ 4285int 4286vmapbuf(struct buf *bp, int mapbuf) 4287{ 4288 caddr_t kva; 4289 vm_prot_t prot; 4290 int pidx; 4291 4292 if (bp->b_bufsize < 0) 4293 return (-1); 4294 prot = VM_PROT_READ; 4295 if (bp->b_iocmd == BIO_READ) 4296 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 4297 if ((pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 4298 (vm_offset_t)bp->b_data, bp->b_bufsize, prot, bp->b_pages, 4299 btoc(MAXPHYS))) < 0) 4300 return (-1); 4301 bp->b_npages = pidx; 4302 if (mapbuf || !unmapped_buf_allowed) { 4303 pmap_qenter((vm_offset_t)bp->b_saveaddr, bp->b_pages, pidx); 4304 kva = bp->b_saveaddr; 4305 bp->b_saveaddr = bp->b_data; 4306 bp->b_data = kva + (((vm_offset_t)bp->b_data) & PAGE_MASK); 4307 bp->b_flags &= ~B_UNMAPPED; 4308 } else { 4309 bp->b_flags |= B_UNMAPPED; 4310 bp->b_offset = ((vm_offset_t)bp->b_data) & PAGE_MASK; 4311 bp->b_saveaddr = bp->b_data; 4312 bp->b_data = unmapped_buf; 4313 } 4314 return(0); 4315} 4316 4317/* 4318 * Free the io map PTEs associated with this IO operation. 4319 * We also invalidate the TLB entries and restore the original b_addr. 4320 */ 4321void 4322vunmapbuf(struct buf *bp) 4323{ 4324 int npages; 4325 4326 npages = bp->b_npages; 4327 if (bp->b_flags & B_UNMAPPED) 4328 bp->b_flags &= ~B_UNMAPPED; 4329 else 4330 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages); 4331 vm_page_unhold_pages(bp->b_pages, npages); 4332 4333 bp->b_data = bp->b_saveaddr; 4334} 4335 4336void 4337bdone(struct buf *bp) 4338{ 4339 struct mtx *mtxp; 4340 4341 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4342 mtx_lock(mtxp); 4343 bp->b_flags |= B_DONE; 4344 wakeup(bp); 4345 mtx_unlock(mtxp); 4346} 4347 4348void 4349bwait(struct buf *bp, u_char pri, const char *wchan) 4350{ 4351 struct mtx *mtxp; 4352 4353 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4354 mtx_lock(mtxp); 4355 while ((bp->b_flags & B_DONE) == 0) 4356 msleep(bp, mtxp, pri, wchan, 0); 4357 mtx_unlock(mtxp); 4358} 4359 4360int 4361bufsync(struct bufobj *bo, int waitfor) 4362{ 4363 4364 return (VOP_FSYNC(bo->__bo_vnode, waitfor, curthread)); 4365} 4366 4367void 4368bufstrategy(struct bufobj *bo, struct buf *bp) 4369{ 4370 int i = 0; 4371 struct vnode *vp; 4372 4373 vp = bp->b_vp; 4374 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy")); 4375 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 4376 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp)); 4377 i = VOP_STRATEGY(vp, bp); 4378 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp)); 4379} 4380 4381void 4382bufobj_wrefl(struct bufobj *bo) 4383{ 4384 4385 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 4386 ASSERT_BO_WLOCKED(bo); 4387 bo->bo_numoutput++; 4388} 4389 4390void 4391bufobj_wref(struct bufobj *bo) 4392{ 4393 4394 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 4395 BO_LOCK(bo); 4396 bo->bo_numoutput++; 4397 BO_UNLOCK(bo); 4398} 4399 4400void 4401bufobj_wdrop(struct bufobj *bo) 4402{ 4403 4404 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop")); 4405 BO_LOCK(bo); 4406 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count")); 4407 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) { 4408 bo->bo_flag &= ~BO_WWAIT; 4409 wakeup(&bo->bo_numoutput); 4410 } 4411 BO_UNLOCK(bo); 4412} 4413 4414int 4415bufobj_wwait(struct bufobj *bo, int slpflag, int timeo) 4416{ 4417 int error; 4418 4419 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait")); 4420 ASSERT_BO_WLOCKED(bo); 4421 error = 0; 4422 while (bo->bo_numoutput) { 4423 bo->bo_flag |= BO_WWAIT; 4424 error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo), 4425 slpflag | (PRIBIO + 1), "bo_wwait", timeo); 4426 if (error) 4427 break; 4428 } 4429 return (error); 4430} 4431 4432void 4433bpin(struct buf *bp) 4434{ 4435 struct mtx *mtxp; 4436 4437 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4438 mtx_lock(mtxp); 4439 bp->b_pin_count++; 4440 mtx_unlock(mtxp); 4441} 4442 4443void 4444bunpin(struct buf *bp) 4445{ 4446 struct mtx *mtxp; 4447 4448 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4449 mtx_lock(mtxp); 4450 if (--bp->b_pin_count == 0) 4451 wakeup(bp); 4452 mtx_unlock(mtxp); 4453} 4454 4455void 4456bunpin_wait(struct buf *bp) 4457{ 4458 struct mtx *mtxp; 4459 4460 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4461 mtx_lock(mtxp); 4462 while (bp->b_pin_count > 0) 4463 msleep(bp, mtxp, PRIBIO, "bwunpin", 0); 4464 mtx_unlock(mtxp); 4465} 4466 4467/* 4468 * Set bio_data or bio_ma for struct bio from the struct buf. 4469 */ 4470void 4471bdata2bio(struct buf *bp, struct bio *bip) 4472{ 4473 4474 if ((bp->b_flags & B_UNMAPPED) != 0) { 4475 KASSERT(unmapped_buf_allowed, ("unmapped")); 4476 bip->bio_ma = bp->b_pages; 4477 bip->bio_ma_n = bp->b_npages; 4478 bip->bio_data = unmapped_buf; 4479 bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK; 4480 bip->bio_flags |= BIO_UNMAPPED; 4481 KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) / 4482 PAGE_SIZE == bp->b_npages, 4483 ("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset, 4484 (long long)bip->bio_length, bip->bio_ma_n)); 4485 } else { 4486 bip->bio_data = bp->b_data; 4487 bip->bio_ma = NULL; 4488 } 4489} 4490 4491#include "opt_ddb.h" 4492#ifdef DDB 4493#include <ddb/ddb.h> 4494 4495/* DDB command to show buffer data */ 4496DB_SHOW_COMMAND(buffer, db_show_buffer) 4497{ 4498 /* get args */ 4499 struct buf *bp = (struct buf *)addr; 4500 4501 if (!have_addr) { 4502 db_printf("usage: show buffer <addr>\n"); 4503 return; 4504 } 4505 4506 db_printf("buf at %p\n", bp); 4507 db_printf("b_flags = 0x%b, b_xflags=0x%b, b_vflags=0x%b\n", 4508 (u_int)bp->b_flags, PRINT_BUF_FLAGS, (u_int)bp->b_xflags, 4509 PRINT_BUF_XFLAGS, (u_int)bp->b_vflags, PRINT_BUF_VFLAGS); 4510 db_printf( 4511 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n" 4512 "b_bufobj = (%p), b_data = %p, b_blkno = %jd, b_lblkno = %jd, " 4513 "b_dep = %p\n", 4514 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 4515 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno, 4516 (intmax_t)bp->b_lblkno, bp->b_dep.lh_first); 4517 if (bp->b_npages) { 4518 int i; 4519 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 4520 for (i = 0; i < bp->b_npages; i++) { 4521 vm_page_t m; 4522 m = bp->b_pages[i]; 4523 db_printf("(%p, 0x%lx, 0x%lx)", (void *)m->object, 4524 (u_long)m->pindex, (u_long)VM_PAGE_TO_PHYS(m)); 4525 if ((i + 1) < bp->b_npages) 4526 db_printf(","); 4527 } 4528 db_printf("\n"); 4529 } 4530 db_printf(" "); 4531 BUF_LOCKPRINTINFO(bp); 4532} 4533 4534DB_SHOW_COMMAND(lockedbufs, lockedbufs) 4535{ 4536 struct buf *bp; 4537 int i; 4538 4539 for (i = 0; i < nbuf; i++) { 4540 bp = &buf[i]; 4541 if (BUF_ISLOCKED(bp)) { 4542 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 4543 db_printf("\n"); 4544 } 4545 } 4546} 4547 4548DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs) 4549{ 4550 struct vnode *vp; 4551 struct buf *bp; 4552 4553 if (!have_addr) { 4554 db_printf("usage: show vnodebufs <addr>\n"); 4555 return; 4556 } 4557 vp = (struct vnode *)addr; 4558 db_printf("Clean buffers:\n"); 4559 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) { 4560 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 4561 db_printf("\n"); 4562 } 4563 db_printf("Dirty buffers:\n"); 4564 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) { 4565 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 4566 db_printf("\n"); 4567 } 4568} 4569 4570DB_COMMAND(countfreebufs, db_coundfreebufs) 4571{ 4572 struct buf *bp; 4573 int i, used = 0, nfree = 0; 4574 4575 if (have_addr) { 4576 db_printf("usage: countfreebufs\n"); 4577 return; 4578 } 4579 4580 for (i = 0; i < nbuf; i++) { 4581 bp = &buf[i]; 4582 if ((bp->b_flags & B_INFREECNT) != 0) 4583 nfree++; 4584 else 4585 used++; 4586 } 4587 4588 db_printf("Counted %d free, %d used (%d tot)\n", nfree, used, 4589 nfree + used); 4590 db_printf("numfreebuffers is %d\n", numfreebuffers); 4591} 4592#endif /* DDB */ 4593