1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2004 Poul-Henning Kamp 5 * Copyright (c) 1994,1997 John S. Dyson 6 * Copyright (c) 2013 The FreeBSD Foundation 7 * All rights reserved. 8 * 9 * Portions of this software were developed by Konstantin Belousov 10 * under sponsorship from the FreeBSD Foundation. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * this file contains a new buffer I/O scheme implementing a coherent 36 * VM object and buffer cache scheme. Pains have been taken to make 37 * sure that the performance degradation associated with schemes such 38 * as this is not realized. 39 * 40 * Author: John S. Dyson 41 * Significant help during the development and debugging phases 42 * had been provided by David Greenman, also of the FreeBSD core team. 43 * 44 * see man buf(9) for more info. 45 */ 46 47 #include <sys/cdefs.h> 48 __FBSDID("$FreeBSD$"); 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/asan.h> 53 #include <sys/bio.h> 54 #include <sys/bitset.h> 55 #include <sys/boottrace.h> 56 #include <sys/buf.h> 57 #include <sys/conf.h> 58 #include <sys/counter.h> 59 #include <sys/devicestat.h> 60 #include <sys/eventhandler.h> 61 #include <sys/fail.h> 62 #include <sys/ktr.h> 63 #include <sys/limits.h> 64 #include <sys/lock.h> 65 #include <sys/malloc.h> 66 #include <sys/mount.h> 67 #include <sys/mutex.h> 68 #include <sys/kernel.h> 69 #include <sys/kthread.h> 70 #include <sys/proc.h> 71 #include <sys/racct.h> 72 #include <sys/refcount.h> 73 #include <sys/resourcevar.h> 74 #include <sys/rwlock.h> 75 #include <sys/sched.h> 76 #include <sys/smp.h> 77 #include <sys/sysctl.h> 78 #include <sys/syscallsubr.h> 79 #include <sys/vmem.h> 80 #include <sys/vmmeter.h> 81 #include <sys/vnode.h> 82 #include <sys/watchdog.h> 83 #include <geom/geom.h> 84 #include <vm/vm.h> 85 #include <vm/vm_param.h> 86 #include <vm/vm_kern.h> 87 #include <vm/vm_object.h> 88 #include <vm/vm_page.h> 89 #include <vm/vm_pageout.h> 90 #include <vm/vm_pager.h> 91 #include <vm/vm_extern.h> 92 #include <vm/vm_map.h> 93 #include <vm/swap_pager.h> 94 95 static MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer"); 96 97 struct bio_ops bioops; /* I/O operation notification */ 98 99 struct buf_ops buf_ops_bio = { 100 .bop_name = "buf_ops_bio", 101 .bop_write = bufwrite, 102 .bop_strategy = bufstrategy, 103 .bop_sync = bufsync, 104 .bop_bdflush = bufbdflush, 105 }; 106 107 struct bufqueue { 108 struct mtx_padalign bq_lock; 109 TAILQ_HEAD(, buf) bq_queue; 110 uint8_t bq_index; 111 uint16_t bq_subqueue; 112 int bq_len; 113 } __aligned(CACHE_LINE_SIZE); 114 115 #define BQ_LOCKPTR(bq) (&(bq)->bq_lock) 116 #define BQ_LOCK(bq) mtx_lock(BQ_LOCKPTR((bq))) 117 #define BQ_UNLOCK(bq) mtx_unlock(BQ_LOCKPTR((bq))) 118 #define BQ_ASSERT_LOCKED(bq) mtx_assert(BQ_LOCKPTR((bq)), MA_OWNED) 119 120 struct bufdomain { 121 struct bufqueue *bd_subq; 122 struct bufqueue bd_dirtyq; 123 struct bufqueue *bd_cleanq; 124 struct mtx_padalign bd_run_lock; 125 /* Constants */ 126 long bd_maxbufspace; 127 long bd_hibufspace; 128 long bd_lobufspace; 129 long bd_bufspacethresh; 130 int bd_hifreebuffers; 131 int bd_lofreebuffers; 132 int bd_hidirtybuffers; 133 int bd_lodirtybuffers; 134 int bd_dirtybufthresh; 135 int bd_lim; 136 /* atomics */ 137 int bd_wanted; 138 bool bd_shutdown; 139 int __aligned(CACHE_LINE_SIZE) bd_numdirtybuffers; 140 int __aligned(CACHE_LINE_SIZE) bd_running; 141 long __aligned(CACHE_LINE_SIZE) bd_bufspace; 142 int __aligned(CACHE_LINE_SIZE) bd_freebuffers; 143 } __aligned(CACHE_LINE_SIZE); 144 145 #define BD_LOCKPTR(bd) (&(bd)->bd_cleanq->bq_lock) 146 #define BD_LOCK(bd) mtx_lock(BD_LOCKPTR((bd))) 147 #define BD_UNLOCK(bd) mtx_unlock(BD_LOCKPTR((bd))) 148 #define BD_ASSERT_LOCKED(bd) mtx_assert(BD_LOCKPTR((bd)), MA_OWNED) 149 #define BD_RUN_LOCKPTR(bd) (&(bd)->bd_run_lock) 150 #define BD_RUN_LOCK(bd) mtx_lock(BD_RUN_LOCKPTR((bd))) 151 #define BD_RUN_UNLOCK(bd) mtx_unlock(BD_RUN_LOCKPTR((bd))) 152 #define BD_DOMAIN(bd) (bd - bdomain) 153 154 static char *buf; /* buffer header pool */ 155 static struct buf * 156 nbufp(unsigned i) 157 { 158 return ((struct buf *)(buf + (sizeof(struct buf) + 159 sizeof(vm_page_t) * atop(maxbcachebuf)) * i)); 160 } 161 162 caddr_t __read_mostly unmapped_buf; 163 164 /* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.c */ 165 struct proc *bufdaemonproc; 166 167 static void vm_hold_free_pages(struct buf *bp, int newbsize); 168 static void vm_hold_load_pages(struct buf *bp, vm_offset_t from, 169 vm_offset_t to); 170 static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m); 171 static void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, 172 vm_page_t m); 173 static void vfs_clean_pages_dirty_buf(struct buf *bp); 174 static void vfs_setdirty_range(struct buf *bp); 175 static void vfs_vmio_invalidate(struct buf *bp); 176 static void vfs_vmio_truncate(struct buf *bp, int npages); 177 static void vfs_vmio_extend(struct buf *bp, int npages, int size); 178 static int vfs_bio_clcheck(struct vnode *vp, int size, 179 daddr_t lblkno, daddr_t blkno); 180 static void breada(struct vnode *, daddr_t *, int *, int, struct ucred *, int, 181 void (*)(struct buf *)); 182 static int buf_flush(struct vnode *vp, struct bufdomain *, int); 183 static int flushbufqueues(struct vnode *, struct bufdomain *, int, int); 184 static void buf_daemon(void); 185 static __inline void bd_wakeup(void); 186 static int sysctl_runningspace(SYSCTL_HANDLER_ARGS); 187 static void bufkva_reclaim(vmem_t *, int); 188 static void bufkva_free(struct buf *); 189 static int buf_import(void *, void **, int, int, int); 190 static void buf_release(void *, void **, int); 191 static void maxbcachebuf_adjust(void); 192 static inline struct bufdomain *bufdomain(struct buf *); 193 static void bq_remove(struct bufqueue *bq, struct buf *bp); 194 static void bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock); 195 static int buf_recycle(struct bufdomain *, bool kva); 196 static void bq_init(struct bufqueue *bq, int qindex, int cpu, 197 const char *lockname); 198 static void bd_init(struct bufdomain *bd); 199 static int bd_flushall(struct bufdomain *bd); 200 static int sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS); 201 static int sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS); 202 203 static int sysctl_bufspace(SYSCTL_HANDLER_ARGS); 204 int vmiodirenable = TRUE; 205 SYSCTL_INT(_vfs, OID_AUTO, vmiodirenable, CTLFLAG_RW, &vmiodirenable, 0, 206 "Use the VM system for directory writes"); 207 long runningbufspace; 208 SYSCTL_LONG(_vfs, OID_AUTO, runningbufspace, CTLFLAG_RD, &runningbufspace, 0, 209 "Amount of presently outstanding async buffer io"); 210 SYSCTL_PROC(_vfs, OID_AUTO, bufspace, CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RD, 211 NULL, 0, sysctl_bufspace, "L", "Physical memory used for buffers"); 212 static counter_u64_t bufkvaspace; 213 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufkvaspace, CTLFLAG_RD, &bufkvaspace, 214 "Kernel virtual memory used for buffers"); 215 static long maxbufspace; 216 SYSCTL_PROC(_vfs, OID_AUTO, maxbufspace, 217 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &maxbufspace, 218 __offsetof(struct bufdomain, bd_maxbufspace), sysctl_bufdomain_long, "L", 219 "Maximum allowed value of bufspace (including metadata)"); 220 static long bufmallocspace; 221 SYSCTL_LONG(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0, 222 "Amount of malloced memory for buffers"); 223 static long maxbufmallocspace; 224 SYSCTL_LONG(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace, 225 0, "Maximum amount of malloced memory for buffers"); 226 static long lobufspace; 227 SYSCTL_PROC(_vfs, OID_AUTO, lobufspace, 228 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &lobufspace, 229 __offsetof(struct bufdomain, bd_lobufspace), sysctl_bufdomain_long, "L", 230 "Minimum amount of buffers we want to have"); 231 long hibufspace; 232 SYSCTL_PROC(_vfs, OID_AUTO, hibufspace, 233 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &hibufspace, 234 __offsetof(struct bufdomain, bd_hibufspace), sysctl_bufdomain_long, "L", 235 "Maximum allowed value of bufspace (excluding metadata)"); 236 long bufspacethresh; 237 SYSCTL_PROC(_vfs, OID_AUTO, bufspacethresh, 238 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &bufspacethresh, 239 __offsetof(struct bufdomain, bd_bufspacethresh), sysctl_bufdomain_long, "L", 240 "Bufspace consumed before waking the daemon to free some"); 241 static counter_u64_t buffreekvacnt; 242 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, buffreekvacnt, CTLFLAG_RW, &buffreekvacnt, 243 "Number of times we have freed the KVA space from some buffer"); 244 static counter_u64_t bufdefragcnt; 245 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufdefragcnt, CTLFLAG_RW, &bufdefragcnt, 246 "Number of times we have had to repeat buffer allocation to defragment"); 247 static long lorunningspace; 248 SYSCTL_PROC(_vfs, OID_AUTO, lorunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 249 CTLFLAG_RW, &lorunningspace, 0, sysctl_runningspace, "L", 250 "Minimum preferred space used for in-progress I/O"); 251 static long hirunningspace; 252 SYSCTL_PROC(_vfs, OID_AUTO, hirunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 253 CTLFLAG_RW, &hirunningspace, 0, sysctl_runningspace, "L", 254 "Maximum amount of space to use for in-progress I/O"); 255 int dirtybufferflushes; 256 SYSCTL_INT(_vfs, OID_AUTO, dirtybufferflushes, CTLFLAG_RW, &dirtybufferflushes, 257 0, "Number of bdwrite to bawrite conversions to limit dirty buffers"); 258 int bdwriteskip; 259 SYSCTL_INT(_vfs, OID_AUTO, bdwriteskip, CTLFLAG_RW, &bdwriteskip, 260 0, "Number of buffers supplied to bdwrite with snapshot deadlock risk"); 261 int altbufferflushes; 262 SYSCTL_INT(_vfs, OID_AUTO, altbufferflushes, CTLFLAG_RW | CTLFLAG_STATS, 263 &altbufferflushes, 0, "Number of fsync flushes to limit dirty buffers"); 264 static int recursiveflushes; 265 SYSCTL_INT(_vfs, OID_AUTO, recursiveflushes, CTLFLAG_RW | CTLFLAG_STATS, 266 &recursiveflushes, 0, "Number of flushes skipped due to being recursive"); 267 static int sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS); 268 SYSCTL_PROC(_vfs, OID_AUTO, numdirtybuffers, 269 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RD, NULL, 0, sysctl_numdirtybuffers, "I", 270 "Number of buffers that are dirty (has unwritten changes) at the moment"); 271 static int lodirtybuffers; 272 SYSCTL_PROC(_vfs, OID_AUTO, lodirtybuffers, 273 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lodirtybuffers, 274 __offsetof(struct bufdomain, bd_lodirtybuffers), sysctl_bufdomain_int, "I", 275 "How many buffers we want to have free before bufdaemon can sleep"); 276 static int hidirtybuffers; 277 SYSCTL_PROC(_vfs, OID_AUTO, hidirtybuffers, 278 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hidirtybuffers, 279 __offsetof(struct bufdomain, bd_hidirtybuffers), sysctl_bufdomain_int, "I", 280 "When the number of dirty buffers is considered severe"); 281 int dirtybufthresh; 282 SYSCTL_PROC(_vfs, OID_AUTO, dirtybufthresh, 283 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &dirtybufthresh, 284 __offsetof(struct bufdomain, bd_dirtybufthresh), sysctl_bufdomain_int, "I", 285 "Number of bdwrite to bawrite conversions to clear dirty buffers"); 286 static int numfreebuffers; 287 SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0, 288 "Number of free buffers"); 289 static int lofreebuffers; 290 SYSCTL_PROC(_vfs, OID_AUTO, lofreebuffers, 291 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lofreebuffers, 292 __offsetof(struct bufdomain, bd_lofreebuffers), sysctl_bufdomain_int, "I", 293 "Target number of free buffers"); 294 static int hifreebuffers; 295 SYSCTL_PROC(_vfs, OID_AUTO, hifreebuffers, 296 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hifreebuffers, 297 __offsetof(struct bufdomain, bd_hifreebuffers), sysctl_bufdomain_int, "I", 298 "Threshold for clean buffer recycling"); 299 static counter_u64_t getnewbufcalls; 300 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufcalls, CTLFLAG_RD, 301 &getnewbufcalls, "Number of calls to getnewbuf"); 302 static counter_u64_t getnewbufrestarts; 303 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufrestarts, CTLFLAG_RD, 304 &getnewbufrestarts, 305 "Number of times getnewbuf has had to restart a buffer acquisition"); 306 static counter_u64_t mappingrestarts; 307 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, mappingrestarts, CTLFLAG_RD, 308 &mappingrestarts, 309 "Number of times getblk has had to restart a buffer mapping for " 310 "unmapped buffer"); 311 static counter_u64_t numbufallocfails; 312 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, numbufallocfails, CTLFLAG_RW, 313 &numbufallocfails, "Number of times buffer allocations failed"); 314 static int flushbufqtarget = 100; 315 SYSCTL_INT(_vfs, OID_AUTO, flushbufqtarget, CTLFLAG_RW, &flushbufqtarget, 0, 316 "Amount of work to do in flushbufqueues when helping bufdaemon"); 317 static counter_u64_t notbufdflushes; 318 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, notbufdflushes, CTLFLAG_RD, ¬bufdflushes, 319 "Number of dirty buffer flushes done by the bufdaemon helpers"); 320 static long barrierwrites; 321 SYSCTL_LONG(_vfs, OID_AUTO, barrierwrites, CTLFLAG_RW | CTLFLAG_STATS, 322 &barrierwrites, 0, "Number of barrier writes"); 323 SYSCTL_INT(_vfs, OID_AUTO, unmapped_buf_allowed, CTLFLAG_RD, 324 &unmapped_buf_allowed, 0, 325 "Permit the use of the unmapped i/o"); 326 int maxbcachebuf = MAXBCACHEBUF; 327 SYSCTL_INT(_vfs, OID_AUTO, maxbcachebuf, CTLFLAG_RDTUN, &maxbcachebuf, 0, 328 "Maximum size of a buffer cache block"); 329 330 /* 331 * This lock synchronizes access to bd_request. 332 */ 333 static struct mtx_padalign __exclusive_cache_line bdlock; 334 335 /* 336 * This lock protects the runningbufreq and synchronizes runningbufwakeup and 337 * waitrunningbufspace(). 338 */ 339 static struct mtx_padalign __exclusive_cache_line rbreqlock; 340 341 /* 342 * Lock that protects bdirtywait. 343 */ 344 static struct mtx_padalign __exclusive_cache_line bdirtylock; 345 346 /* 347 * bufdaemon shutdown request and sleep channel. 348 */ 349 static bool bd_shutdown; 350 351 /* 352 * Wakeup point for bufdaemon, as well as indicator of whether it is already 353 * active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it 354 * is idling. 355 */ 356 static int bd_request; 357 358 /* 359 * Request for the buf daemon to write more buffers than is indicated by 360 * lodirtybuf. This may be necessary to push out excess dependencies or 361 * defragment the address space where a simple count of the number of dirty 362 * buffers is insufficient to characterize the demand for flushing them. 363 */ 364 static int bd_speedupreq; 365 366 /* 367 * Synchronization (sleep/wakeup) variable for active buffer space requests. 368 * Set when wait starts, cleared prior to wakeup(). 369 * Used in runningbufwakeup() and waitrunningbufspace(). 370 */ 371 static int runningbufreq; 372 373 /* 374 * Synchronization for bwillwrite() waiters. 375 */ 376 static int bdirtywait; 377 378 /* 379 * Definitions for the buffer free lists. 380 */ 381 #define QUEUE_NONE 0 /* on no queue */ 382 #define QUEUE_EMPTY 1 /* empty buffer headers */ 383 #define QUEUE_DIRTY 2 /* B_DELWRI buffers */ 384 #define QUEUE_CLEAN 3 /* non-B_DELWRI buffers */ 385 #define QUEUE_SENTINEL 4 /* not an queue index, but mark for sentinel */ 386 387 /* Maximum number of buffer domains. */ 388 #define BUF_DOMAINS 8 389 390 struct bufdomainset bdlodirty; /* Domains > lodirty */ 391 struct bufdomainset bdhidirty; /* Domains > hidirty */ 392 393 /* Configured number of clean queues. */ 394 static int __read_mostly buf_domains; 395 396 BITSET_DEFINE(bufdomainset, BUF_DOMAINS); 397 struct bufdomain __exclusive_cache_line bdomain[BUF_DOMAINS]; 398 struct bufqueue __exclusive_cache_line bqempty; 399 400 /* 401 * per-cpu empty buffer cache. 402 */ 403 uma_zone_t buf_zone; 404 405 static int 406 sysctl_runningspace(SYSCTL_HANDLER_ARGS) 407 { 408 long value; 409 int error; 410 411 value = *(long *)arg1; 412 error = sysctl_handle_long(oidp, &value, 0, req); 413 if (error != 0 || req->newptr == NULL) 414 return (error); 415 mtx_lock(&rbreqlock); 416 if (arg1 == &hirunningspace) { 417 if (value < lorunningspace) 418 error = EINVAL; 419 else 420 hirunningspace = value; 421 } else { 422 KASSERT(arg1 == &lorunningspace, 423 ("%s: unknown arg1", __func__)); 424 if (value > hirunningspace) 425 error = EINVAL; 426 else 427 lorunningspace = value; 428 } 429 mtx_unlock(&rbreqlock); 430 return (error); 431 } 432 433 static int 434 sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS) 435 { 436 int error; 437 int value; 438 int i; 439 440 value = *(int *)arg1; 441 error = sysctl_handle_int(oidp, &value, 0, req); 442 if (error != 0 || req->newptr == NULL) 443 return (error); 444 *(int *)arg1 = value; 445 for (i = 0; i < buf_domains; i++) 446 *(int *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 447 value / buf_domains; 448 449 return (error); 450 } 451 452 static int 453 sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS) 454 { 455 long value; 456 int error; 457 int i; 458 459 value = *(long *)arg1; 460 error = sysctl_handle_long(oidp, &value, 0, req); 461 if (error != 0 || req->newptr == NULL) 462 return (error); 463 *(long *)arg1 = value; 464 for (i = 0; i < buf_domains; i++) 465 *(long *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 466 value / buf_domains; 467 468 return (error); 469 } 470 471 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 472 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 473 static int 474 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 475 { 476 long lvalue; 477 int ivalue; 478 int i; 479 480 lvalue = 0; 481 for (i = 0; i < buf_domains; i++) 482 lvalue += bdomain[i].bd_bufspace; 483 if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long)) 484 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 485 if (lvalue > INT_MAX) 486 /* On overflow, still write out a long to trigger ENOMEM. */ 487 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 488 ivalue = lvalue; 489 return (sysctl_handle_int(oidp, &ivalue, 0, req)); 490 } 491 #else 492 static int 493 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 494 { 495 long lvalue; 496 int i; 497 498 lvalue = 0; 499 for (i = 0; i < buf_domains; i++) 500 lvalue += bdomain[i].bd_bufspace; 501 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 502 } 503 #endif 504 505 static int 506 sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS) 507 { 508 int value; 509 int i; 510 511 value = 0; 512 for (i = 0; i < buf_domains; i++) 513 value += bdomain[i].bd_numdirtybuffers; 514 return (sysctl_handle_int(oidp, &value, 0, req)); 515 } 516 517 /* 518 * bdirtywakeup: 519 * 520 * Wakeup any bwillwrite() waiters. 521 */ 522 static void 523 bdirtywakeup(void) 524 { 525 mtx_lock(&bdirtylock); 526 if (bdirtywait) { 527 bdirtywait = 0; 528 wakeup(&bdirtywait); 529 } 530 mtx_unlock(&bdirtylock); 531 } 532 533 /* 534 * bd_clear: 535 * 536 * Clear a domain from the appropriate bitsets when dirtybuffers 537 * is decremented. 538 */ 539 static void 540 bd_clear(struct bufdomain *bd) 541 { 542 543 mtx_lock(&bdirtylock); 544 if (bd->bd_numdirtybuffers <= bd->bd_lodirtybuffers) 545 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 546 if (bd->bd_numdirtybuffers <= bd->bd_hidirtybuffers) 547 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 548 mtx_unlock(&bdirtylock); 549 } 550 551 /* 552 * bd_set: 553 * 554 * Set a domain in the appropriate bitsets when dirtybuffers 555 * is incremented. 556 */ 557 static void 558 bd_set(struct bufdomain *bd) 559 { 560 561 mtx_lock(&bdirtylock); 562 if (bd->bd_numdirtybuffers > bd->bd_lodirtybuffers) 563 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 564 if (bd->bd_numdirtybuffers > bd->bd_hidirtybuffers) 565 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 566 mtx_unlock(&bdirtylock); 567 } 568 569 /* 570 * bdirtysub: 571 * 572 * Decrement the numdirtybuffers count by one and wakeup any 573 * threads blocked in bwillwrite(). 574 */ 575 static void 576 bdirtysub(struct buf *bp) 577 { 578 struct bufdomain *bd; 579 int num; 580 581 bd = bufdomain(bp); 582 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, -1); 583 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 584 bdirtywakeup(); 585 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 586 bd_clear(bd); 587 } 588 589 /* 590 * bdirtyadd: 591 * 592 * Increment the numdirtybuffers count by one and wakeup the buf 593 * daemon if needed. 594 */ 595 static void 596 bdirtyadd(struct buf *bp) 597 { 598 struct bufdomain *bd; 599 int num; 600 601 /* 602 * Only do the wakeup once as we cross the boundary. The 603 * buf daemon will keep running until the condition clears. 604 */ 605 bd = bufdomain(bp); 606 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, 1); 607 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 608 bd_wakeup(); 609 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 610 bd_set(bd); 611 } 612 613 /* 614 * bufspace_daemon_wakeup: 615 * 616 * Wakeup the daemons responsible for freeing clean bufs. 617 */ 618 static void 619 bufspace_daemon_wakeup(struct bufdomain *bd) 620 { 621 622 /* 623 * avoid the lock if the daemon is running. 624 */ 625 if (atomic_fetchadd_int(&bd->bd_running, 1) == 0) { 626 BD_RUN_LOCK(bd); 627 atomic_store_int(&bd->bd_running, 1); 628 wakeup(&bd->bd_running); 629 BD_RUN_UNLOCK(bd); 630 } 631 } 632 633 /* 634 * bufspace_adjust: 635 * 636 * Adjust the reported bufspace for a KVA managed buffer, possibly 637 * waking any waiters. 638 */ 639 static void 640 bufspace_adjust(struct buf *bp, int bufsize) 641 { 642 struct bufdomain *bd; 643 long space; 644 int diff; 645 646 KASSERT((bp->b_flags & B_MALLOC) == 0, 647 ("bufspace_adjust: malloc buf %p", bp)); 648 bd = bufdomain(bp); 649 diff = bufsize - bp->b_bufsize; 650 if (diff < 0) { 651 atomic_subtract_long(&bd->bd_bufspace, -diff); 652 } else if (diff > 0) { 653 space = atomic_fetchadd_long(&bd->bd_bufspace, diff); 654 /* Wake up the daemon on the transition. */ 655 if (space < bd->bd_bufspacethresh && 656 space + diff >= bd->bd_bufspacethresh) 657 bufspace_daemon_wakeup(bd); 658 } 659 bp->b_bufsize = bufsize; 660 } 661 662 /* 663 * bufspace_reserve: 664 * 665 * Reserve bufspace before calling allocbuf(). metadata has a 666 * different space limit than data. 667 */ 668 static int 669 bufspace_reserve(struct bufdomain *bd, int size, bool metadata) 670 { 671 long limit, new; 672 long space; 673 674 if (metadata) 675 limit = bd->bd_maxbufspace; 676 else 677 limit = bd->bd_hibufspace; 678 space = atomic_fetchadd_long(&bd->bd_bufspace, size); 679 new = space + size; 680 if (new > limit) { 681 atomic_subtract_long(&bd->bd_bufspace, size); 682 return (ENOSPC); 683 } 684 685 /* Wake up the daemon on the transition. */ 686 if (space < bd->bd_bufspacethresh && new >= bd->bd_bufspacethresh) 687 bufspace_daemon_wakeup(bd); 688 689 return (0); 690 } 691 692 /* 693 * bufspace_release: 694 * 695 * Release reserved bufspace after bufspace_adjust() has consumed it. 696 */ 697 static void 698 bufspace_release(struct bufdomain *bd, int size) 699 { 700 701 atomic_subtract_long(&bd->bd_bufspace, size); 702 } 703 704 /* 705 * bufspace_wait: 706 * 707 * Wait for bufspace, acting as the buf daemon if a locked vnode is 708 * supplied. bd_wanted must be set prior to polling for space. The 709 * operation must be re-tried on return. 710 */ 711 static void 712 bufspace_wait(struct bufdomain *bd, struct vnode *vp, int gbflags, 713 int slpflag, int slptimeo) 714 { 715 struct thread *td; 716 int error, fl, norunbuf; 717 718 if ((gbflags & GB_NOWAIT_BD) != 0) 719 return; 720 721 td = curthread; 722 BD_LOCK(bd); 723 while (bd->bd_wanted) { 724 if (vp != NULL && vp->v_type != VCHR && 725 (td->td_pflags & TDP_BUFNEED) == 0) { 726 BD_UNLOCK(bd); 727 /* 728 * getblk() is called with a vnode locked, and 729 * some majority of the dirty buffers may as 730 * well belong to the vnode. Flushing the 731 * buffers there would make a progress that 732 * cannot be achieved by the buf_daemon, that 733 * cannot lock the vnode. 734 */ 735 norunbuf = ~(TDP_BUFNEED | TDP_NORUNNINGBUF) | 736 (td->td_pflags & TDP_NORUNNINGBUF); 737 738 /* 739 * Play bufdaemon. The getnewbuf() function 740 * may be called while the thread owns lock 741 * for another dirty buffer for the same 742 * vnode, which makes it impossible to use 743 * VOP_FSYNC() there, due to the buffer lock 744 * recursion. 745 */ 746 td->td_pflags |= TDP_BUFNEED | TDP_NORUNNINGBUF; 747 fl = buf_flush(vp, bd, flushbufqtarget); 748 td->td_pflags &= norunbuf; 749 BD_LOCK(bd); 750 if (fl != 0) 751 continue; 752 if (bd->bd_wanted == 0) 753 break; 754 } 755 error = msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 756 (PRIBIO + 4) | slpflag, "newbuf", slptimeo); 757 if (error != 0) 758 break; 759 } 760 BD_UNLOCK(bd); 761 } 762 763 static void 764 bufspace_daemon_shutdown(void *arg, int howto __unused) 765 { 766 struct bufdomain *bd = arg; 767 int error; 768 769 if (KERNEL_PANICKED()) 770 return; 771 772 BD_RUN_LOCK(bd); 773 bd->bd_shutdown = true; 774 wakeup(&bd->bd_running); 775 error = msleep(&bd->bd_shutdown, BD_RUN_LOCKPTR(bd), 0, 776 "bufspace_shutdown", 60 * hz); 777 BD_RUN_UNLOCK(bd); 778 if (error != 0) 779 printf("bufspacedaemon wait error: %d\n", error); 780 } 781 782 /* 783 * bufspace_daemon: 784 * 785 * buffer space management daemon. Tries to maintain some marginal 786 * amount of free buffer space so that requesting processes neither 787 * block nor work to reclaim buffers. 788 */ 789 static void 790 bufspace_daemon(void *arg) 791 { 792 struct bufdomain *bd = arg; 793 794 EVENTHANDLER_REGISTER(shutdown_pre_sync, bufspace_daemon_shutdown, bd, 795 SHUTDOWN_PRI_LAST + 100); 796 797 BD_RUN_LOCK(bd); 798 while (!bd->bd_shutdown) { 799 BD_RUN_UNLOCK(bd); 800 801 /* 802 * Free buffers from the clean queue until we meet our 803 * targets. 804 * 805 * Theory of operation: The buffer cache is most efficient 806 * when some free buffer headers and space are always 807 * available to getnewbuf(). This daemon attempts to prevent 808 * the excessive blocking and synchronization associated 809 * with shortfall. It goes through three phases according 810 * demand: 811 * 812 * 1) The daemon wakes up voluntarily once per-second 813 * during idle periods when the counters are below 814 * the wakeup thresholds (bufspacethresh, lofreebuffers). 815 * 816 * 2) The daemon wakes up as we cross the thresholds 817 * ahead of any potential blocking. This may bounce 818 * slightly according to the rate of consumption and 819 * release. 820 * 821 * 3) The daemon and consumers are starved for working 822 * clean buffers. This is the 'bufspace' sleep below 823 * which will inefficiently trade bufs with bqrelse 824 * until we return to condition 2. 825 */ 826 while (bd->bd_bufspace > bd->bd_lobufspace || 827 bd->bd_freebuffers < bd->bd_hifreebuffers) { 828 if (buf_recycle(bd, false) != 0) { 829 if (bd_flushall(bd)) 830 continue; 831 /* 832 * Speedup dirty if we've run out of clean 833 * buffers. This is possible in particular 834 * because softdep may held many bufs locked 835 * pending writes to other bufs which are 836 * marked for delayed write, exhausting 837 * clean space until they are written. 838 */ 839 bd_speedup(); 840 BD_LOCK(bd); 841 if (bd->bd_wanted) { 842 msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 843 PRIBIO|PDROP, "bufspace", hz/10); 844 } else 845 BD_UNLOCK(bd); 846 } 847 maybe_yield(); 848 } 849 850 /* 851 * Re-check our limits and sleep. bd_running must be 852 * cleared prior to checking the limits to avoid missed 853 * wakeups. The waker will adjust one of bufspace or 854 * freebuffers prior to checking bd_running. 855 */ 856 BD_RUN_LOCK(bd); 857 if (bd->bd_shutdown) 858 break; 859 atomic_store_int(&bd->bd_running, 0); 860 if (bd->bd_bufspace < bd->bd_bufspacethresh && 861 bd->bd_freebuffers > bd->bd_lofreebuffers) { 862 msleep(&bd->bd_running, BD_RUN_LOCKPTR(bd), 863 PRIBIO, "-", hz); 864 } else { 865 /* Avoid spurious wakeups while running. */ 866 atomic_store_int(&bd->bd_running, 1); 867 } 868 } 869 wakeup(&bd->bd_shutdown); 870 BD_RUN_UNLOCK(bd); 871 kthread_exit(); 872 } 873 874 /* 875 * bufmallocadjust: 876 * 877 * Adjust the reported bufspace for a malloc managed buffer, possibly 878 * waking any waiters. 879 */ 880 static void 881 bufmallocadjust(struct buf *bp, int bufsize) 882 { 883 int diff; 884 885 KASSERT((bp->b_flags & B_MALLOC) != 0, 886 ("bufmallocadjust: non-malloc buf %p", bp)); 887 diff = bufsize - bp->b_bufsize; 888 if (diff < 0) 889 atomic_subtract_long(&bufmallocspace, -diff); 890 else 891 atomic_add_long(&bufmallocspace, diff); 892 bp->b_bufsize = bufsize; 893 } 894 895 /* 896 * runningwakeup: 897 * 898 * Wake up processes that are waiting on asynchronous writes to fall 899 * below lorunningspace. 900 */ 901 static void 902 runningwakeup(void) 903 { 904 905 mtx_lock(&rbreqlock); 906 if (runningbufreq) { 907 runningbufreq = 0; 908 wakeup(&runningbufreq); 909 } 910 mtx_unlock(&rbreqlock); 911 } 912 913 /* 914 * runningbufwakeup: 915 * 916 * Decrement the outstanding write count according. 917 */ 918 void 919 runningbufwakeup(struct buf *bp) 920 { 921 long space, bspace; 922 923 bspace = bp->b_runningbufspace; 924 if (bspace == 0) 925 return; 926 space = atomic_fetchadd_long(&runningbufspace, -bspace); 927 KASSERT(space >= bspace, ("runningbufspace underflow %ld %ld", 928 space, bspace)); 929 bp->b_runningbufspace = 0; 930 /* 931 * Only acquire the lock and wakeup on the transition from exceeding 932 * the threshold to falling below it. 933 */ 934 if (space < lorunningspace) 935 return; 936 if (space - bspace > lorunningspace) 937 return; 938 runningwakeup(); 939 } 940 941 /* 942 * waitrunningbufspace() 943 * 944 * runningbufspace is a measure of the amount of I/O currently 945 * running. This routine is used in async-write situations to 946 * prevent creating huge backups of pending writes to a device. 947 * Only asynchronous writes are governed by this function. 948 * 949 * This does NOT turn an async write into a sync write. It waits 950 * for earlier writes to complete and generally returns before the 951 * caller's write has reached the device. 952 */ 953 void 954 waitrunningbufspace(void) 955 { 956 957 mtx_lock(&rbreqlock); 958 while (runningbufspace > hirunningspace) { 959 runningbufreq = 1; 960 msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0); 961 } 962 mtx_unlock(&rbreqlock); 963 } 964 965 /* 966 * vfs_buf_test_cache: 967 * 968 * Called when a buffer is extended. This function clears the B_CACHE 969 * bit if the newly extended portion of the buffer does not contain 970 * valid data. 971 */ 972 static __inline void 973 vfs_buf_test_cache(struct buf *bp, vm_ooffset_t foff, vm_offset_t off, 974 vm_offset_t size, vm_page_t m) 975 { 976 977 /* 978 * This function and its results are protected by higher level 979 * synchronization requiring vnode and buf locks to page in and 980 * validate pages. 981 */ 982 if (bp->b_flags & B_CACHE) { 983 int base = (foff + off) & PAGE_MASK; 984 if (vm_page_is_valid(m, base, size) == 0) 985 bp->b_flags &= ~B_CACHE; 986 } 987 } 988 989 /* Wake up the buffer daemon if necessary */ 990 static void 991 bd_wakeup(void) 992 { 993 994 mtx_lock(&bdlock); 995 if (bd_request == 0) { 996 bd_request = 1; 997 wakeup(&bd_request); 998 } 999 mtx_unlock(&bdlock); 1000 } 1001 1002 /* 1003 * Adjust the maxbcachbuf tunable. 1004 */ 1005 static void 1006 maxbcachebuf_adjust(void) 1007 { 1008 int i; 1009 1010 /* 1011 * maxbcachebuf must be a power of 2 >= MAXBSIZE. 1012 */ 1013 i = 2; 1014 while (i * 2 <= maxbcachebuf) 1015 i *= 2; 1016 maxbcachebuf = i; 1017 if (maxbcachebuf < MAXBSIZE) 1018 maxbcachebuf = MAXBSIZE; 1019 if (maxbcachebuf > maxphys) 1020 maxbcachebuf = maxphys; 1021 if (bootverbose != 0 && maxbcachebuf != MAXBCACHEBUF) 1022 printf("maxbcachebuf=%d\n", maxbcachebuf); 1023 } 1024 1025 /* 1026 * bd_speedup - speedup the buffer cache flushing code 1027 */ 1028 void 1029 bd_speedup(void) 1030 { 1031 int needwake; 1032 1033 mtx_lock(&bdlock); 1034 needwake = 0; 1035 if (bd_speedupreq == 0 || bd_request == 0) 1036 needwake = 1; 1037 bd_speedupreq = 1; 1038 bd_request = 1; 1039 if (needwake) 1040 wakeup(&bd_request); 1041 mtx_unlock(&bdlock); 1042 } 1043 1044 #ifdef __i386__ 1045 #define TRANSIENT_DENOM 5 1046 #else 1047 #define TRANSIENT_DENOM 10 1048 #endif 1049 1050 /* 1051 * Calculating buffer cache scaling values and reserve space for buffer 1052 * headers. This is called during low level kernel initialization and 1053 * may be called more then once. We CANNOT write to the memory area 1054 * being reserved at this time. 1055 */ 1056 caddr_t 1057 kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est) 1058 { 1059 int tuned_nbuf; 1060 long maxbuf, maxbuf_sz, buf_sz, biotmap_sz; 1061 1062 /* 1063 * With KASAN or KMSAN enabled, the kernel map is shadowed. Account for 1064 * this when sizing maps based on the amount of physical memory 1065 * available. 1066 */ 1067 #if defined(KASAN) 1068 physmem_est = (physmem_est * KASAN_SHADOW_SCALE) / 1069 (KASAN_SHADOW_SCALE + 1); 1070 #elif defined(KMSAN) 1071 physmem_est /= 3; 1072 1073 /* 1074 * KMSAN cannot reliably determine whether buffer data is initialized 1075 * unless it is updated through a KVA mapping. 1076 */ 1077 unmapped_buf_allowed = 0; 1078 #endif 1079 1080 /* 1081 * physmem_est is in pages. Convert it to kilobytes (assumes 1082 * PAGE_SIZE is >= 1K) 1083 */ 1084 physmem_est = physmem_est * (PAGE_SIZE / 1024); 1085 1086 maxbcachebuf_adjust(); 1087 /* 1088 * The nominal buffer size (and minimum KVA allocation) is BKVASIZE. 1089 * For the first 64MB of ram nominally allocate sufficient buffers to 1090 * cover 1/4 of our ram. Beyond the first 64MB allocate additional 1091 * buffers to cover 1/10 of our ram over 64MB. When auto-sizing 1092 * the buffer cache we limit the eventual kva reservation to 1093 * maxbcache bytes. 1094 * 1095 * factor represents the 1/4 x ram conversion. 1096 */ 1097 if (nbuf == 0) { 1098 int factor = 4 * BKVASIZE / 1024; 1099 1100 nbuf = 50; 1101 if (physmem_est > 4096) 1102 nbuf += min((physmem_est - 4096) / factor, 1103 65536 / factor); 1104 if (physmem_est > 65536) 1105 nbuf += min((physmem_est - 65536) * 2 / (factor * 5), 1106 32 * 1024 * 1024 / (factor * 5)); 1107 1108 if (maxbcache && nbuf > maxbcache / BKVASIZE) 1109 nbuf = maxbcache / BKVASIZE; 1110 tuned_nbuf = 1; 1111 } else 1112 tuned_nbuf = 0; 1113 1114 /* XXX Avoid unsigned long overflows later on with maxbufspace. */ 1115 maxbuf = (LONG_MAX / 3) / BKVASIZE; 1116 if (nbuf > maxbuf) { 1117 if (!tuned_nbuf) 1118 printf("Warning: nbufs lowered from %d to %ld\n", nbuf, 1119 maxbuf); 1120 nbuf = maxbuf; 1121 } 1122 1123 /* 1124 * Ideal allocation size for the transient bio submap is 10% 1125 * of the maximal space buffer map. This roughly corresponds 1126 * to the amount of the buffer mapped for typical UFS load. 1127 * 1128 * Clip the buffer map to reserve space for the transient 1129 * BIOs, if its extent is bigger than 90% (80% on i386) of the 1130 * maximum buffer map extent on the platform. 1131 * 1132 * The fall-back to the maxbuf in case of maxbcache unset, 1133 * allows to not trim the buffer KVA for the architectures 1134 * with ample KVA space. 1135 */ 1136 if (bio_transient_maxcnt == 0 && unmapped_buf_allowed) { 1137 maxbuf_sz = maxbcache != 0 ? maxbcache : maxbuf * BKVASIZE; 1138 buf_sz = (long)nbuf * BKVASIZE; 1139 if (buf_sz < maxbuf_sz / TRANSIENT_DENOM * 1140 (TRANSIENT_DENOM - 1)) { 1141 /* 1142 * There is more KVA than memory. Do not 1143 * adjust buffer map size, and assign the rest 1144 * of maxbuf to transient map. 1145 */ 1146 biotmap_sz = maxbuf_sz - buf_sz; 1147 } else { 1148 /* 1149 * Buffer map spans all KVA we could afford on 1150 * this platform. Give 10% (20% on i386) of 1151 * the buffer map to the transient bio map. 1152 */ 1153 biotmap_sz = buf_sz / TRANSIENT_DENOM; 1154 buf_sz -= biotmap_sz; 1155 } 1156 if (biotmap_sz / INT_MAX > maxphys) 1157 bio_transient_maxcnt = INT_MAX; 1158 else 1159 bio_transient_maxcnt = biotmap_sz / maxphys; 1160 /* 1161 * Artificially limit to 1024 simultaneous in-flight I/Os 1162 * using the transient mapping. 1163 */ 1164 if (bio_transient_maxcnt > 1024) 1165 bio_transient_maxcnt = 1024; 1166 if (tuned_nbuf) 1167 nbuf = buf_sz / BKVASIZE; 1168 } 1169 1170 if (nswbuf == 0) { 1171 /* 1172 * Pager buffers are allocated for short periods, so scale the 1173 * number of reserved buffers based on the number of CPUs rather 1174 * than amount of memory. 1175 */ 1176 nswbuf = min(nbuf / 4, 32 * mp_ncpus); 1177 if (nswbuf < NSWBUF_MIN) 1178 nswbuf = NSWBUF_MIN; 1179 } 1180 1181 /* 1182 * Reserve space for the buffer cache buffers 1183 */ 1184 buf = (char *)v; 1185 v = (caddr_t)buf + (sizeof(struct buf) + sizeof(vm_page_t) * 1186 atop(maxbcachebuf)) * nbuf; 1187 1188 return (v); 1189 } 1190 1191 /* 1192 * Single global constant for BUF_WMESG, to avoid getting multiple 1193 * references. 1194 */ 1195 static const char buf_wmesg[] = "bufwait"; 1196 1197 /* Initialize the buffer subsystem. Called before use of any buffers. */ 1198 void 1199 bufinit(void) 1200 { 1201 struct buf *bp; 1202 int i; 1203 1204 TSENTER(); 1205 KASSERT(maxbcachebuf >= MAXBSIZE, 1206 ("maxbcachebuf (%d) must be >= MAXBSIZE (%d)\n", maxbcachebuf, 1207 MAXBSIZE)); 1208 bq_init(&bqempty, QUEUE_EMPTY, -1, "bufq empty lock"); 1209 mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF); 1210 mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF); 1211 mtx_init(&bdirtylock, "dirty buf lock", NULL, MTX_DEF); 1212 1213 unmapped_buf = (caddr_t)kva_alloc(maxphys); 1214 1215 /* finally, initialize each buffer header and stick on empty q */ 1216 for (i = 0; i < nbuf; i++) { 1217 bp = nbufp(i); 1218 bzero(bp, sizeof(*bp) + sizeof(vm_page_t) * atop(maxbcachebuf)); 1219 bp->b_flags = B_INVAL; 1220 bp->b_rcred = NOCRED; 1221 bp->b_wcred = NOCRED; 1222 bp->b_qindex = QUEUE_NONE; 1223 bp->b_domain = -1; 1224 bp->b_subqueue = mp_maxid + 1; 1225 bp->b_xflags = 0; 1226 bp->b_data = bp->b_kvabase = unmapped_buf; 1227 LIST_INIT(&bp->b_dep); 1228 BUF_LOCKINIT(bp, buf_wmesg); 1229 bq_insert(&bqempty, bp, false); 1230 } 1231 1232 /* 1233 * maxbufspace is the absolute maximum amount of buffer space we are 1234 * allowed to reserve in KVM and in real terms. The absolute maximum 1235 * is nominally used by metadata. hibufspace is the nominal maximum 1236 * used by most other requests. The differential is required to 1237 * ensure that metadata deadlocks don't occur. 1238 * 1239 * maxbufspace is based on BKVASIZE. Allocating buffers larger then 1240 * this may result in KVM fragmentation which is not handled optimally 1241 * by the system. XXX This is less true with vmem. We could use 1242 * PAGE_SIZE. 1243 */ 1244 maxbufspace = (long)nbuf * BKVASIZE; 1245 hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - maxbcachebuf * 10); 1246 lobufspace = (hibufspace / 20) * 19; /* 95% */ 1247 bufspacethresh = lobufspace + (hibufspace - lobufspace) / 2; 1248 1249 /* 1250 * Note: The 16 MiB upper limit for hirunningspace was chosen 1251 * arbitrarily and may need further tuning. It corresponds to 1252 * 128 outstanding write IO requests (if IO size is 128 KiB), 1253 * which fits with many RAID controllers' tagged queuing limits. 1254 * The lower 1 MiB limit is the historical upper limit for 1255 * hirunningspace. 1256 */ 1257 hirunningspace = lmax(lmin(roundup(hibufspace / 64, maxbcachebuf), 1258 16 * 1024 * 1024), 1024 * 1024); 1259 lorunningspace = roundup((hirunningspace * 2) / 3, maxbcachebuf); 1260 1261 /* 1262 * Limit the amount of malloc memory since it is wired permanently into 1263 * the kernel space. Even though this is accounted for in the buffer 1264 * allocation, we don't want the malloced region to grow uncontrolled. 1265 * The malloc scheme improves memory utilization significantly on 1266 * average (small) directories. 1267 */ 1268 maxbufmallocspace = hibufspace / 20; 1269 1270 /* 1271 * Reduce the chance of a deadlock occurring by limiting the number 1272 * of delayed-write dirty buffers we allow to stack up. 1273 */ 1274 hidirtybuffers = nbuf / 4 + 20; 1275 dirtybufthresh = hidirtybuffers * 9 / 10; 1276 /* 1277 * To support extreme low-memory systems, make sure hidirtybuffers 1278 * cannot eat up all available buffer space. This occurs when our 1279 * minimum cannot be met. We try to size hidirtybuffers to 3/4 our 1280 * buffer space assuming BKVASIZE'd buffers. 1281 */ 1282 while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) { 1283 hidirtybuffers >>= 1; 1284 } 1285 lodirtybuffers = hidirtybuffers / 2; 1286 1287 /* 1288 * lofreebuffers should be sufficient to avoid stalling waiting on 1289 * buf headers under heavy utilization. The bufs in per-cpu caches 1290 * are counted as free but will be unavailable to threads executing 1291 * on other cpus. 1292 * 1293 * hifreebuffers is the free target for the bufspace daemon. This 1294 * should be set appropriately to limit work per-iteration. 1295 */ 1296 lofreebuffers = MIN((nbuf / 25) + (20 * mp_ncpus), 128 * mp_ncpus); 1297 hifreebuffers = (3 * lofreebuffers) / 2; 1298 numfreebuffers = nbuf; 1299 1300 /* Setup the kva and free list allocators. */ 1301 vmem_set_reclaim(buffer_arena, bufkva_reclaim); 1302 buf_zone = uma_zcache_create("buf free cache", 1303 sizeof(struct buf) + sizeof(vm_page_t) * atop(maxbcachebuf), 1304 NULL, NULL, NULL, NULL, buf_import, buf_release, NULL, 0); 1305 1306 /* 1307 * Size the clean queue according to the amount of buffer space. 1308 * One queue per-256mb up to the max. More queues gives better 1309 * concurrency but less accurate LRU. 1310 */ 1311 buf_domains = MIN(howmany(maxbufspace, 256*1024*1024), BUF_DOMAINS); 1312 for (i = 0 ; i < buf_domains; i++) { 1313 struct bufdomain *bd; 1314 1315 bd = &bdomain[i]; 1316 bd_init(bd); 1317 bd->bd_freebuffers = nbuf / buf_domains; 1318 bd->bd_hifreebuffers = hifreebuffers / buf_domains; 1319 bd->bd_lofreebuffers = lofreebuffers / buf_domains; 1320 bd->bd_bufspace = 0; 1321 bd->bd_maxbufspace = maxbufspace / buf_domains; 1322 bd->bd_hibufspace = hibufspace / buf_domains; 1323 bd->bd_lobufspace = lobufspace / buf_domains; 1324 bd->bd_bufspacethresh = bufspacethresh / buf_domains; 1325 bd->bd_numdirtybuffers = 0; 1326 bd->bd_hidirtybuffers = hidirtybuffers / buf_domains; 1327 bd->bd_lodirtybuffers = lodirtybuffers / buf_domains; 1328 bd->bd_dirtybufthresh = dirtybufthresh / buf_domains; 1329 /* Don't allow more than 2% of bufs in the per-cpu caches. */ 1330 bd->bd_lim = nbuf / buf_domains / 50 / mp_ncpus; 1331 } 1332 getnewbufcalls = counter_u64_alloc(M_WAITOK); 1333 getnewbufrestarts = counter_u64_alloc(M_WAITOK); 1334 mappingrestarts = counter_u64_alloc(M_WAITOK); 1335 numbufallocfails = counter_u64_alloc(M_WAITOK); 1336 notbufdflushes = counter_u64_alloc(M_WAITOK); 1337 buffreekvacnt = counter_u64_alloc(M_WAITOK); 1338 bufdefragcnt = counter_u64_alloc(M_WAITOK); 1339 bufkvaspace = counter_u64_alloc(M_WAITOK); 1340 TSEXIT(); 1341 } 1342 1343 #ifdef INVARIANTS 1344 static inline void 1345 vfs_buf_check_mapped(struct buf *bp) 1346 { 1347 1348 KASSERT(bp->b_kvabase != unmapped_buf, 1349 ("mapped buf: b_kvabase was not updated %p", bp)); 1350 KASSERT(bp->b_data != unmapped_buf, 1351 ("mapped buf: b_data was not updated %p", bp)); 1352 KASSERT(bp->b_data < unmapped_buf || bp->b_data >= unmapped_buf + 1353 maxphys, ("b_data + b_offset unmapped %p", bp)); 1354 } 1355 1356 static inline void 1357 vfs_buf_check_unmapped(struct buf *bp) 1358 { 1359 1360 KASSERT(bp->b_data == unmapped_buf, 1361 ("unmapped buf: corrupted b_data %p", bp)); 1362 } 1363 1364 #define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp) 1365 #define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp) 1366 #else 1367 #define BUF_CHECK_MAPPED(bp) do {} while (0) 1368 #define BUF_CHECK_UNMAPPED(bp) do {} while (0) 1369 #endif 1370 1371 static int 1372 isbufbusy(struct buf *bp) 1373 { 1374 if (((bp->b_flags & B_INVAL) == 0 && BUF_ISLOCKED(bp)) || 1375 ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)) 1376 return (1); 1377 return (0); 1378 } 1379 1380 /* 1381 * Shutdown the system cleanly to prepare for reboot, halt, or power off. 1382 */ 1383 void 1384 bufshutdown(int show_busybufs) 1385 { 1386 static int first_buf_printf = 1; 1387 struct buf *bp; 1388 int i, iter, nbusy, pbusy; 1389 #ifndef PREEMPTION 1390 int subiter; 1391 #endif 1392 1393 /* 1394 * Sync filesystems for shutdown 1395 */ 1396 wdog_kern_pat(WD_LASTVAL); 1397 kern_sync(curthread); 1398 1399 /* 1400 * With soft updates, some buffers that are 1401 * written will be remarked as dirty until other 1402 * buffers are written. 1403 */ 1404 for (iter = pbusy = 0; iter < 20; iter++) { 1405 nbusy = 0; 1406 for (i = nbuf - 1; i >= 0; i--) { 1407 bp = nbufp(i); 1408 if (isbufbusy(bp)) 1409 nbusy++; 1410 } 1411 if (nbusy == 0) { 1412 if (first_buf_printf) 1413 printf("All buffers synced."); 1414 break; 1415 } 1416 if (first_buf_printf) { 1417 printf("Syncing disks, buffers remaining... "); 1418 first_buf_printf = 0; 1419 } 1420 printf("%d ", nbusy); 1421 if (nbusy < pbusy) 1422 iter = 0; 1423 pbusy = nbusy; 1424 1425 wdog_kern_pat(WD_LASTVAL); 1426 kern_sync(curthread); 1427 1428 #ifdef PREEMPTION 1429 /* 1430 * Spin for a while to allow interrupt threads to run. 1431 */ 1432 DELAY(50000 * iter); 1433 #else 1434 /* 1435 * Context switch several times to allow interrupt 1436 * threads to run. 1437 */ 1438 for (subiter = 0; subiter < 50 * iter; subiter++) { 1439 sched_relinquish(curthread); 1440 DELAY(1000); 1441 } 1442 #endif 1443 } 1444 printf("\n"); 1445 /* 1446 * Count only busy local buffers to prevent forcing 1447 * a fsck if we're just a client of a wedged NFS server 1448 */ 1449 nbusy = 0; 1450 for (i = nbuf - 1; i >= 0; i--) { 1451 bp = nbufp(i); 1452 if (isbufbusy(bp)) { 1453 #if 0 1454 /* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */ 1455 if (bp->b_dev == NULL) { 1456 TAILQ_REMOVE(&mountlist, 1457 bp->b_vp->v_mount, mnt_list); 1458 continue; 1459 } 1460 #endif 1461 nbusy++; 1462 if (show_busybufs > 0) { 1463 printf( 1464 "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:", 1465 nbusy, bp, bp->b_vp, bp->b_flags, 1466 (intmax_t)bp->b_blkno, 1467 (intmax_t)bp->b_lblkno); 1468 BUF_LOCKPRINTINFO(bp); 1469 if (show_busybufs > 1) 1470 vn_printf(bp->b_vp, 1471 "vnode content: "); 1472 } 1473 } 1474 } 1475 if (nbusy) { 1476 /* 1477 * Failed to sync all blocks. Indicate this and don't 1478 * unmount filesystems (thus forcing an fsck on reboot). 1479 */ 1480 BOOTTRACE("shutdown failed to sync buffers"); 1481 printf("Giving up on %d buffers\n", nbusy); 1482 DELAY(5000000); /* 5 seconds */ 1483 swapoff_all(); 1484 } else { 1485 BOOTTRACE("shutdown sync complete"); 1486 if (!first_buf_printf) 1487 printf("Final sync complete\n"); 1488 1489 /* 1490 * Unmount filesystems and perform swapoff, to quiesce 1491 * the system as much as possible. In particular, no 1492 * I/O should be initiated from top levels since it 1493 * might be abruptly terminated by reset, or otherwise 1494 * erronously handled because other parts of the 1495 * system are disabled. 1496 * 1497 * Swapoff before unmount, because file-backed swap is 1498 * non-operational after unmount of the underlying 1499 * filesystem. 1500 */ 1501 if (!KERNEL_PANICKED()) { 1502 swapoff_all(); 1503 vfs_unmountall(); 1504 } 1505 BOOTTRACE("shutdown unmounted all filesystems"); 1506 } 1507 DELAY(100000); /* wait for console output to finish */ 1508 } 1509 1510 static void 1511 bpmap_qenter(struct buf *bp) 1512 { 1513 1514 BUF_CHECK_MAPPED(bp); 1515 1516 /* 1517 * bp->b_data is relative to bp->b_offset, but 1518 * bp->b_offset may be offset into the first page. 1519 */ 1520 bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data); 1521 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 1522 bp->b_data = (caddr_t)((vm_offset_t)bp->b_data | 1523 (vm_offset_t)(bp->b_offset & PAGE_MASK)); 1524 } 1525 1526 static inline struct bufdomain * 1527 bufdomain(struct buf *bp) 1528 { 1529 1530 return (&bdomain[bp->b_domain]); 1531 } 1532 1533 static struct bufqueue * 1534 bufqueue(struct buf *bp) 1535 { 1536 1537 switch (bp->b_qindex) { 1538 case QUEUE_NONE: 1539 /* FALLTHROUGH */ 1540 case QUEUE_SENTINEL: 1541 return (NULL); 1542 case QUEUE_EMPTY: 1543 return (&bqempty); 1544 case QUEUE_DIRTY: 1545 return (&bufdomain(bp)->bd_dirtyq); 1546 case QUEUE_CLEAN: 1547 return (&bufdomain(bp)->bd_subq[bp->b_subqueue]); 1548 default: 1549 break; 1550 } 1551 panic("bufqueue(%p): Unhandled type %d\n", bp, bp->b_qindex); 1552 } 1553 1554 /* 1555 * Return the locked bufqueue that bp is a member of. 1556 */ 1557 static struct bufqueue * 1558 bufqueue_acquire(struct buf *bp) 1559 { 1560 struct bufqueue *bq, *nbq; 1561 1562 /* 1563 * bp can be pushed from a per-cpu queue to the 1564 * cleanq while we're waiting on the lock. Retry 1565 * if the queues don't match. 1566 */ 1567 bq = bufqueue(bp); 1568 BQ_LOCK(bq); 1569 for (;;) { 1570 nbq = bufqueue(bp); 1571 if (bq == nbq) 1572 break; 1573 BQ_UNLOCK(bq); 1574 BQ_LOCK(nbq); 1575 bq = nbq; 1576 } 1577 return (bq); 1578 } 1579 1580 /* 1581 * binsfree: 1582 * 1583 * Insert the buffer into the appropriate free list. Requires a 1584 * locked buffer on entry and buffer is unlocked before return. 1585 */ 1586 static void 1587 binsfree(struct buf *bp, int qindex) 1588 { 1589 struct bufdomain *bd; 1590 struct bufqueue *bq; 1591 1592 KASSERT(qindex == QUEUE_CLEAN || qindex == QUEUE_DIRTY, 1593 ("binsfree: Invalid qindex %d", qindex)); 1594 BUF_ASSERT_XLOCKED(bp); 1595 1596 /* 1597 * Handle delayed bremfree() processing. 1598 */ 1599 if (bp->b_flags & B_REMFREE) { 1600 if (bp->b_qindex == qindex) { 1601 bp->b_flags |= B_REUSE; 1602 bp->b_flags &= ~B_REMFREE; 1603 BUF_UNLOCK(bp); 1604 return; 1605 } 1606 bq = bufqueue_acquire(bp); 1607 bq_remove(bq, bp); 1608 BQ_UNLOCK(bq); 1609 } 1610 bd = bufdomain(bp); 1611 if (qindex == QUEUE_CLEAN) { 1612 if (bd->bd_lim != 0) 1613 bq = &bd->bd_subq[PCPU_GET(cpuid)]; 1614 else 1615 bq = bd->bd_cleanq; 1616 } else 1617 bq = &bd->bd_dirtyq; 1618 bq_insert(bq, bp, true); 1619 } 1620 1621 /* 1622 * buf_free: 1623 * 1624 * Free a buffer to the buf zone once it no longer has valid contents. 1625 */ 1626 static void 1627 buf_free(struct buf *bp) 1628 { 1629 1630 if (bp->b_flags & B_REMFREE) 1631 bremfreef(bp); 1632 if (bp->b_vflags & BV_BKGRDINPROG) 1633 panic("losing buffer 1"); 1634 if (bp->b_rcred != NOCRED) { 1635 crfree(bp->b_rcred); 1636 bp->b_rcred = NOCRED; 1637 } 1638 if (bp->b_wcred != NOCRED) { 1639 crfree(bp->b_wcred); 1640 bp->b_wcred = NOCRED; 1641 } 1642 if (!LIST_EMPTY(&bp->b_dep)) 1643 buf_deallocate(bp); 1644 bufkva_free(bp); 1645 atomic_add_int(&bufdomain(bp)->bd_freebuffers, 1); 1646 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1647 BUF_UNLOCK(bp); 1648 uma_zfree(buf_zone, bp); 1649 } 1650 1651 /* 1652 * buf_import: 1653 * 1654 * Import bufs into the uma cache from the buf list. The system still 1655 * expects a static array of bufs and much of the synchronization 1656 * around bufs assumes type stable storage. As a result, UMA is used 1657 * only as a per-cpu cache of bufs still maintained on a global list. 1658 */ 1659 static int 1660 buf_import(void *arg, void **store, int cnt, int domain, int flags) 1661 { 1662 struct buf *bp; 1663 int i; 1664 1665 BQ_LOCK(&bqempty); 1666 for (i = 0; i < cnt; i++) { 1667 bp = TAILQ_FIRST(&bqempty.bq_queue); 1668 if (bp == NULL) 1669 break; 1670 bq_remove(&bqempty, bp); 1671 store[i] = bp; 1672 } 1673 BQ_UNLOCK(&bqempty); 1674 1675 return (i); 1676 } 1677 1678 /* 1679 * buf_release: 1680 * 1681 * Release bufs from the uma cache back to the buffer queues. 1682 */ 1683 static void 1684 buf_release(void *arg, void **store, int cnt) 1685 { 1686 struct bufqueue *bq; 1687 struct buf *bp; 1688 int i; 1689 1690 bq = &bqempty; 1691 BQ_LOCK(bq); 1692 for (i = 0; i < cnt; i++) { 1693 bp = store[i]; 1694 /* Inline bq_insert() to batch locking. */ 1695 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1696 bp->b_flags &= ~(B_AGE | B_REUSE); 1697 bq->bq_len++; 1698 bp->b_qindex = bq->bq_index; 1699 } 1700 BQ_UNLOCK(bq); 1701 } 1702 1703 /* 1704 * buf_alloc: 1705 * 1706 * Allocate an empty buffer header. 1707 */ 1708 static struct buf * 1709 buf_alloc(struct bufdomain *bd) 1710 { 1711 struct buf *bp; 1712 int freebufs, error; 1713 1714 /* 1715 * We can only run out of bufs in the buf zone if the average buf 1716 * is less than BKVASIZE. In this case the actual wait/block will 1717 * come from buf_reycle() failing to flush one of these small bufs. 1718 */ 1719 bp = NULL; 1720 freebufs = atomic_fetchadd_int(&bd->bd_freebuffers, -1); 1721 if (freebufs > 0) 1722 bp = uma_zalloc(buf_zone, M_NOWAIT); 1723 if (bp == NULL) { 1724 atomic_add_int(&bd->bd_freebuffers, 1); 1725 bufspace_daemon_wakeup(bd); 1726 counter_u64_add(numbufallocfails, 1); 1727 return (NULL); 1728 } 1729 /* 1730 * Wake-up the bufspace daemon on transition below threshold. 1731 */ 1732 if (freebufs == bd->bd_lofreebuffers) 1733 bufspace_daemon_wakeup(bd); 1734 1735 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL); 1736 KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, 1737 error)); 1738 (void)error; 1739 1740 KASSERT(bp->b_vp == NULL, 1741 ("bp: %p still has vnode %p.", bp, bp->b_vp)); 1742 KASSERT((bp->b_flags & (B_DELWRI | B_NOREUSE)) == 0, 1743 ("invalid buffer %p flags %#x", bp, bp->b_flags)); 1744 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0, 1745 ("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags)); 1746 KASSERT(bp->b_npages == 0, 1747 ("bp: %p still has %d vm pages\n", bp, bp->b_npages)); 1748 KASSERT(bp->b_kvasize == 0, ("bp: %p still has kva\n", bp)); 1749 KASSERT(bp->b_bufsize == 0, ("bp: %p still has bufspace\n", bp)); 1750 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1751 1752 bp->b_domain = BD_DOMAIN(bd); 1753 bp->b_flags = 0; 1754 bp->b_ioflags = 0; 1755 bp->b_xflags = 0; 1756 bp->b_vflags = 0; 1757 bp->b_vp = NULL; 1758 bp->b_blkno = bp->b_lblkno = 0; 1759 bp->b_offset = NOOFFSET; 1760 bp->b_iodone = 0; 1761 bp->b_error = 0; 1762 bp->b_resid = 0; 1763 bp->b_bcount = 0; 1764 bp->b_npages = 0; 1765 bp->b_dirtyoff = bp->b_dirtyend = 0; 1766 bp->b_bufobj = NULL; 1767 bp->b_data = bp->b_kvabase = unmapped_buf; 1768 bp->b_fsprivate1 = NULL; 1769 bp->b_fsprivate2 = NULL; 1770 bp->b_fsprivate3 = NULL; 1771 LIST_INIT(&bp->b_dep); 1772 1773 return (bp); 1774 } 1775 1776 /* 1777 * buf_recycle: 1778 * 1779 * Free a buffer from the given bufqueue. kva controls whether the 1780 * freed buf must own some kva resources. This is used for 1781 * defragmenting. 1782 */ 1783 static int 1784 buf_recycle(struct bufdomain *bd, bool kva) 1785 { 1786 struct bufqueue *bq; 1787 struct buf *bp, *nbp; 1788 1789 if (kva) 1790 counter_u64_add(bufdefragcnt, 1); 1791 nbp = NULL; 1792 bq = bd->bd_cleanq; 1793 BQ_LOCK(bq); 1794 KASSERT(BQ_LOCKPTR(bq) == BD_LOCKPTR(bd), 1795 ("buf_recycle: Locks don't match")); 1796 nbp = TAILQ_FIRST(&bq->bq_queue); 1797 1798 /* 1799 * Run scan, possibly freeing data and/or kva mappings on the fly 1800 * depending. 1801 */ 1802 while ((bp = nbp) != NULL) { 1803 /* 1804 * Calculate next bp (we can only use it if we do not 1805 * release the bqlock). 1806 */ 1807 nbp = TAILQ_NEXT(bp, b_freelist); 1808 1809 /* 1810 * If we are defragging then we need a buffer with 1811 * some kva to reclaim. 1812 */ 1813 if (kva && bp->b_kvasize == 0) 1814 continue; 1815 1816 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 1817 continue; 1818 1819 /* 1820 * Implement a second chance algorithm for frequently 1821 * accessed buffers. 1822 */ 1823 if ((bp->b_flags & B_REUSE) != 0) { 1824 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1825 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1826 bp->b_flags &= ~B_REUSE; 1827 BUF_UNLOCK(bp); 1828 continue; 1829 } 1830 1831 /* 1832 * Skip buffers with background writes in progress. 1833 */ 1834 if ((bp->b_vflags & BV_BKGRDINPROG) != 0) { 1835 BUF_UNLOCK(bp); 1836 continue; 1837 } 1838 1839 KASSERT(bp->b_qindex == QUEUE_CLEAN, 1840 ("buf_recycle: inconsistent queue %d bp %p", 1841 bp->b_qindex, bp)); 1842 KASSERT(bp->b_domain == BD_DOMAIN(bd), 1843 ("getnewbuf: queue domain %d doesn't match request %d", 1844 bp->b_domain, (int)BD_DOMAIN(bd))); 1845 /* 1846 * NOTE: nbp is now entirely invalid. We can only restart 1847 * the scan from this point on. 1848 */ 1849 bq_remove(bq, bp); 1850 BQ_UNLOCK(bq); 1851 1852 /* 1853 * Requeue the background write buffer with error and 1854 * restart the scan. 1855 */ 1856 if ((bp->b_vflags & BV_BKGRDERR) != 0) { 1857 bqrelse(bp); 1858 BQ_LOCK(bq); 1859 nbp = TAILQ_FIRST(&bq->bq_queue); 1860 continue; 1861 } 1862 bp->b_flags |= B_INVAL; 1863 brelse(bp); 1864 return (0); 1865 } 1866 bd->bd_wanted = 1; 1867 BQ_UNLOCK(bq); 1868 1869 return (ENOBUFS); 1870 } 1871 1872 /* 1873 * bremfree: 1874 * 1875 * Mark the buffer for removal from the appropriate free list. 1876 * 1877 */ 1878 void 1879 bremfree(struct buf *bp) 1880 { 1881 1882 CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1883 KASSERT((bp->b_flags & B_REMFREE) == 0, 1884 ("bremfree: buffer %p already marked for delayed removal.", bp)); 1885 KASSERT(bp->b_qindex != QUEUE_NONE, 1886 ("bremfree: buffer %p not on a queue.", bp)); 1887 BUF_ASSERT_XLOCKED(bp); 1888 1889 bp->b_flags |= B_REMFREE; 1890 } 1891 1892 /* 1893 * bremfreef: 1894 * 1895 * Force an immediate removal from a free list. Used only in nfs when 1896 * it abuses the b_freelist pointer. 1897 */ 1898 void 1899 bremfreef(struct buf *bp) 1900 { 1901 struct bufqueue *bq; 1902 1903 bq = bufqueue_acquire(bp); 1904 bq_remove(bq, bp); 1905 BQ_UNLOCK(bq); 1906 } 1907 1908 static void 1909 bq_init(struct bufqueue *bq, int qindex, int subqueue, const char *lockname) 1910 { 1911 1912 mtx_init(&bq->bq_lock, lockname, NULL, MTX_DEF); 1913 TAILQ_INIT(&bq->bq_queue); 1914 bq->bq_len = 0; 1915 bq->bq_index = qindex; 1916 bq->bq_subqueue = subqueue; 1917 } 1918 1919 static void 1920 bd_init(struct bufdomain *bd) 1921 { 1922 int i; 1923 1924 /* Per-CPU clean buf queues, plus one global queue. */ 1925 bd->bd_subq = mallocarray(mp_maxid + 2, sizeof(struct bufqueue), 1926 M_BIOBUF, M_WAITOK | M_ZERO); 1927 bd->bd_cleanq = &bd->bd_subq[mp_maxid + 1]; 1928 bq_init(bd->bd_cleanq, QUEUE_CLEAN, mp_maxid + 1, "bufq clean lock"); 1929 bq_init(&bd->bd_dirtyq, QUEUE_DIRTY, -1, "bufq dirty lock"); 1930 for (i = 0; i <= mp_maxid; i++) 1931 bq_init(&bd->bd_subq[i], QUEUE_CLEAN, i, 1932 "bufq clean subqueue lock"); 1933 mtx_init(&bd->bd_run_lock, "bufspace daemon run lock", NULL, MTX_DEF); 1934 } 1935 1936 /* 1937 * bq_remove: 1938 * 1939 * Removes a buffer from the free list, must be called with the 1940 * correct qlock held. 1941 */ 1942 static void 1943 bq_remove(struct bufqueue *bq, struct buf *bp) 1944 { 1945 1946 CTR3(KTR_BUF, "bq_remove(%p) vp %p flags %X", 1947 bp, bp->b_vp, bp->b_flags); 1948 KASSERT(bp->b_qindex != QUEUE_NONE, 1949 ("bq_remove: buffer %p not on a queue.", bp)); 1950 KASSERT(bufqueue(bp) == bq, 1951 ("bq_remove: Remove buffer %p from wrong queue.", bp)); 1952 1953 BQ_ASSERT_LOCKED(bq); 1954 if (bp->b_qindex != QUEUE_EMPTY) { 1955 BUF_ASSERT_XLOCKED(bp); 1956 } 1957 KASSERT(bq->bq_len >= 1, 1958 ("queue %d underflow", bp->b_qindex)); 1959 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1960 bq->bq_len--; 1961 bp->b_qindex = QUEUE_NONE; 1962 bp->b_flags &= ~(B_REMFREE | B_REUSE); 1963 } 1964 1965 static void 1966 bd_flush(struct bufdomain *bd, struct bufqueue *bq) 1967 { 1968 struct buf *bp; 1969 1970 BQ_ASSERT_LOCKED(bq); 1971 if (bq != bd->bd_cleanq) { 1972 BD_LOCK(bd); 1973 while ((bp = TAILQ_FIRST(&bq->bq_queue)) != NULL) { 1974 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1975 TAILQ_INSERT_TAIL(&bd->bd_cleanq->bq_queue, bp, 1976 b_freelist); 1977 bp->b_subqueue = bd->bd_cleanq->bq_subqueue; 1978 } 1979 bd->bd_cleanq->bq_len += bq->bq_len; 1980 bq->bq_len = 0; 1981 } 1982 if (bd->bd_wanted) { 1983 bd->bd_wanted = 0; 1984 wakeup(&bd->bd_wanted); 1985 } 1986 if (bq != bd->bd_cleanq) 1987 BD_UNLOCK(bd); 1988 } 1989 1990 static int 1991 bd_flushall(struct bufdomain *bd) 1992 { 1993 struct bufqueue *bq; 1994 int flushed; 1995 int i; 1996 1997 if (bd->bd_lim == 0) 1998 return (0); 1999 flushed = 0; 2000 for (i = 0; i <= mp_maxid; i++) { 2001 bq = &bd->bd_subq[i]; 2002 if (bq->bq_len == 0) 2003 continue; 2004 BQ_LOCK(bq); 2005 bd_flush(bd, bq); 2006 BQ_UNLOCK(bq); 2007 flushed++; 2008 } 2009 2010 return (flushed); 2011 } 2012 2013 static void 2014 bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock) 2015 { 2016 struct bufdomain *bd; 2017 2018 if (bp->b_qindex != QUEUE_NONE) 2019 panic("bq_insert: free buffer %p onto another queue?", bp); 2020 2021 bd = bufdomain(bp); 2022 if (bp->b_flags & B_AGE) { 2023 /* Place this buf directly on the real queue. */ 2024 if (bq->bq_index == QUEUE_CLEAN) 2025 bq = bd->bd_cleanq; 2026 BQ_LOCK(bq); 2027 TAILQ_INSERT_HEAD(&bq->bq_queue, bp, b_freelist); 2028 } else { 2029 BQ_LOCK(bq); 2030 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 2031 } 2032 bp->b_flags &= ~(B_AGE | B_REUSE); 2033 bq->bq_len++; 2034 bp->b_qindex = bq->bq_index; 2035 bp->b_subqueue = bq->bq_subqueue; 2036 2037 /* 2038 * Unlock before we notify so that we don't wakeup a waiter that 2039 * fails a trylock on the buf and sleeps again. 2040 */ 2041 if (unlock) 2042 BUF_UNLOCK(bp); 2043 2044 if (bp->b_qindex == QUEUE_CLEAN) { 2045 /* 2046 * Flush the per-cpu queue and notify any waiters. 2047 */ 2048 if (bd->bd_wanted || (bq != bd->bd_cleanq && 2049 bq->bq_len >= bd->bd_lim)) 2050 bd_flush(bd, bq); 2051 } 2052 BQ_UNLOCK(bq); 2053 } 2054 2055 /* 2056 * bufkva_free: 2057 * 2058 * Free the kva allocation for a buffer. 2059 * 2060 */ 2061 static void 2062 bufkva_free(struct buf *bp) 2063 { 2064 2065 #ifdef INVARIANTS 2066 if (bp->b_kvasize == 0) { 2067 KASSERT(bp->b_kvabase == unmapped_buf && 2068 bp->b_data == unmapped_buf, 2069 ("Leaked KVA space on %p", bp)); 2070 } else if (buf_mapped(bp)) 2071 BUF_CHECK_MAPPED(bp); 2072 else 2073 BUF_CHECK_UNMAPPED(bp); 2074 #endif 2075 if (bp->b_kvasize == 0) 2076 return; 2077 2078 vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, bp->b_kvasize); 2079 counter_u64_add(bufkvaspace, -bp->b_kvasize); 2080 counter_u64_add(buffreekvacnt, 1); 2081 bp->b_data = bp->b_kvabase = unmapped_buf; 2082 bp->b_kvasize = 0; 2083 } 2084 2085 /* 2086 * bufkva_alloc: 2087 * 2088 * Allocate the buffer KVA and set b_kvasize and b_kvabase. 2089 */ 2090 static int 2091 bufkva_alloc(struct buf *bp, int maxsize, int gbflags) 2092 { 2093 vm_offset_t addr; 2094 int error; 2095 2096 KASSERT((gbflags & GB_UNMAPPED) == 0 || (gbflags & GB_KVAALLOC) != 0, 2097 ("Invalid gbflags 0x%x in %s", gbflags, __func__)); 2098 MPASS((bp->b_flags & B_MAXPHYS) == 0); 2099 KASSERT(maxsize <= maxbcachebuf, 2100 ("bufkva_alloc kva too large %d %u", maxsize, maxbcachebuf)); 2101 2102 bufkva_free(bp); 2103 2104 addr = 0; 2105 error = vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr); 2106 if (error != 0) { 2107 /* 2108 * Buffer map is too fragmented. Request the caller 2109 * to defragment the map. 2110 */ 2111 return (error); 2112 } 2113 bp->b_kvabase = (caddr_t)addr; 2114 bp->b_kvasize = maxsize; 2115 counter_u64_add(bufkvaspace, bp->b_kvasize); 2116 if ((gbflags & GB_UNMAPPED) != 0) { 2117 bp->b_data = unmapped_buf; 2118 BUF_CHECK_UNMAPPED(bp); 2119 } else { 2120 bp->b_data = bp->b_kvabase; 2121 BUF_CHECK_MAPPED(bp); 2122 } 2123 return (0); 2124 } 2125 2126 /* 2127 * bufkva_reclaim: 2128 * 2129 * Reclaim buffer kva by freeing buffers holding kva. This is a vmem 2130 * callback that fires to avoid returning failure. 2131 */ 2132 static void 2133 bufkva_reclaim(vmem_t *vmem, int flags) 2134 { 2135 bool done; 2136 int q; 2137 int i; 2138 2139 done = false; 2140 for (i = 0; i < 5; i++) { 2141 for (q = 0; q < buf_domains; q++) 2142 if (buf_recycle(&bdomain[q], true) != 0) 2143 done = true; 2144 if (done) 2145 break; 2146 } 2147 return; 2148 } 2149 2150 /* 2151 * Attempt to initiate asynchronous I/O on read-ahead blocks. We must 2152 * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set, 2153 * the buffer is valid and we do not have to do anything. 2154 */ 2155 static void 2156 breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt, 2157 struct ucred * cred, int flags, void (*ckhashfunc)(struct buf *)) 2158 { 2159 struct buf *rabp; 2160 struct thread *td; 2161 int i; 2162 2163 td = curthread; 2164 2165 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 2166 if (inmem(vp, *rablkno)) 2167 continue; 2168 rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0); 2169 if ((rabp->b_flags & B_CACHE) != 0) { 2170 brelse(rabp); 2171 continue; 2172 } 2173 #ifdef RACCT 2174 if (racct_enable) { 2175 PROC_LOCK(curproc); 2176 racct_add_buf(curproc, rabp, 0); 2177 PROC_UNLOCK(curproc); 2178 } 2179 #endif /* RACCT */ 2180 td->td_ru.ru_inblock++; 2181 rabp->b_flags |= B_ASYNC; 2182 rabp->b_flags &= ~B_INVAL; 2183 if ((flags & GB_CKHASH) != 0) { 2184 rabp->b_flags |= B_CKHASH; 2185 rabp->b_ckhashcalc = ckhashfunc; 2186 } 2187 rabp->b_ioflags &= ~BIO_ERROR; 2188 rabp->b_iocmd = BIO_READ; 2189 if (rabp->b_rcred == NOCRED && cred != NOCRED) 2190 rabp->b_rcred = crhold(cred); 2191 vfs_busy_pages(rabp, 0); 2192 BUF_KERNPROC(rabp); 2193 rabp->b_iooffset = dbtob(rabp->b_blkno); 2194 bstrategy(rabp); 2195 } 2196 } 2197 2198 /* 2199 * Entry point for bread() and breadn() via #defines in sys/buf.h. 2200 * 2201 * Get a buffer with the specified data. Look in the cache first. We 2202 * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE 2203 * is set, the buffer is valid and we do not have to do anything, see 2204 * getblk(). Also starts asynchronous I/O on read-ahead blocks. 2205 * 2206 * Always return a NULL buffer pointer (in bpp) when returning an error. 2207 * 2208 * The blkno parameter is the logical block being requested. Normally 2209 * the mapping of logical block number to disk block address is done 2210 * by calling VOP_BMAP(). However, if the mapping is already known, the 2211 * disk block address can be passed using the dblkno parameter. If the 2212 * disk block address is not known, then the same value should be passed 2213 * for blkno and dblkno. 2214 */ 2215 int 2216 breadn_flags(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, 2217 daddr_t *rablkno, int *rabsize, int cnt, struct ucred *cred, int flags, 2218 void (*ckhashfunc)(struct buf *), struct buf **bpp) 2219 { 2220 struct buf *bp; 2221 struct thread *td; 2222 int error, readwait, rv; 2223 2224 CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size); 2225 td = curthread; 2226 /* 2227 * Can only return NULL if GB_LOCK_NOWAIT or GB_SPARSE flags 2228 * are specified. 2229 */ 2230 error = getblkx(vp, blkno, dblkno, size, 0, 0, flags, &bp); 2231 if (error != 0) { 2232 *bpp = NULL; 2233 return (error); 2234 } 2235 KASSERT(blkno == bp->b_lblkno, 2236 ("getblkx returned buffer for blkno %jd instead of blkno %jd", 2237 (intmax_t)bp->b_lblkno, (intmax_t)blkno)); 2238 flags &= ~GB_NOSPARSE; 2239 *bpp = bp; 2240 2241 /* 2242 * If not found in cache, do some I/O 2243 */ 2244 readwait = 0; 2245 if ((bp->b_flags & B_CACHE) == 0) { 2246 #ifdef RACCT 2247 if (racct_enable) { 2248 PROC_LOCK(td->td_proc); 2249 racct_add_buf(td->td_proc, bp, 0); 2250 PROC_UNLOCK(td->td_proc); 2251 } 2252 #endif /* RACCT */ 2253 td->td_ru.ru_inblock++; 2254 bp->b_iocmd = BIO_READ; 2255 bp->b_flags &= ~B_INVAL; 2256 if ((flags & GB_CKHASH) != 0) { 2257 bp->b_flags |= B_CKHASH; 2258 bp->b_ckhashcalc = ckhashfunc; 2259 } 2260 if ((flags & GB_CVTENXIO) != 0) 2261 bp->b_xflags |= BX_CVTENXIO; 2262 bp->b_ioflags &= ~BIO_ERROR; 2263 if (bp->b_rcred == NOCRED && cred != NOCRED) 2264 bp->b_rcred = crhold(cred); 2265 vfs_busy_pages(bp, 0); 2266 bp->b_iooffset = dbtob(bp->b_blkno); 2267 bstrategy(bp); 2268 ++readwait; 2269 } 2270 2271 /* 2272 * Attempt to initiate asynchronous I/O on read-ahead blocks. 2273 */ 2274 breada(vp, rablkno, rabsize, cnt, cred, flags, ckhashfunc); 2275 2276 rv = 0; 2277 if (readwait) { 2278 rv = bufwait(bp); 2279 if (rv != 0) { 2280 brelse(bp); 2281 *bpp = NULL; 2282 } 2283 } 2284 return (rv); 2285 } 2286 2287 /* 2288 * Write, release buffer on completion. (Done by iodone 2289 * if async). Do not bother writing anything if the buffer 2290 * is invalid. 2291 * 2292 * Note that we set B_CACHE here, indicating that buffer is 2293 * fully valid and thus cacheable. This is true even of NFS 2294 * now so we set it generally. This could be set either here 2295 * or in biodone() since the I/O is synchronous. We put it 2296 * here. 2297 */ 2298 int 2299 bufwrite(struct buf *bp) 2300 { 2301 int oldflags; 2302 struct vnode *vp; 2303 long space; 2304 int vp_md; 2305 2306 CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2307 if ((bp->b_bufobj->bo_flag & BO_DEAD) != 0) { 2308 bp->b_flags |= B_INVAL | B_RELBUF; 2309 bp->b_flags &= ~B_CACHE; 2310 brelse(bp); 2311 return (ENXIO); 2312 } 2313 if (bp->b_flags & B_INVAL) { 2314 brelse(bp); 2315 return (0); 2316 } 2317 2318 if (bp->b_flags & B_BARRIER) 2319 atomic_add_long(&barrierwrites, 1); 2320 2321 oldflags = bp->b_flags; 2322 2323 KASSERT(!(bp->b_vflags & BV_BKGRDINPROG), 2324 ("FFS background buffer should not get here %p", bp)); 2325 2326 vp = bp->b_vp; 2327 if (vp) 2328 vp_md = vp->v_vflag & VV_MD; 2329 else 2330 vp_md = 0; 2331 2332 /* 2333 * Mark the buffer clean. Increment the bufobj write count 2334 * before bundirty() call, to prevent other thread from seeing 2335 * empty dirty list and zero counter for writes in progress, 2336 * falsely indicating that the bufobj is clean. 2337 */ 2338 bufobj_wref(bp->b_bufobj); 2339 bundirty(bp); 2340 2341 bp->b_flags &= ~B_DONE; 2342 bp->b_ioflags &= ~BIO_ERROR; 2343 bp->b_flags |= B_CACHE; 2344 bp->b_iocmd = BIO_WRITE; 2345 2346 vfs_busy_pages(bp, 1); 2347 2348 /* 2349 * Normal bwrites pipeline writes 2350 */ 2351 bp->b_runningbufspace = bp->b_bufsize; 2352 space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace); 2353 2354 #ifdef RACCT 2355 if (racct_enable) { 2356 PROC_LOCK(curproc); 2357 racct_add_buf(curproc, bp, 1); 2358 PROC_UNLOCK(curproc); 2359 } 2360 #endif /* RACCT */ 2361 curthread->td_ru.ru_oublock++; 2362 if (oldflags & B_ASYNC) 2363 BUF_KERNPROC(bp); 2364 bp->b_iooffset = dbtob(bp->b_blkno); 2365 buf_track(bp, __func__); 2366 bstrategy(bp); 2367 2368 if ((oldflags & B_ASYNC) == 0) { 2369 int rtval = bufwait(bp); 2370 brelse(bp); 2371 return (rtval); 2372 } else if (space > hirunningspace) { 2373 /* 2374 * don't allow the async write to saturate the I/O 2375 * system. We will not deadlock here because 2376 * we are blocking waiting for I/O that is already in-progress 2377 * to complete. We do not block here if it is the update 2378 * or syncer daemon trying to clean up as that can lead 2379 * to deadlock. 2380 */ 2381 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md) 2382 waitrunningbufspace(); 2383 } 2384 2385 return (0); 2386 } 2387 2388 void 2389 bufbdflush(struct bufobj *bo, struct buf *bp) 2390 { 2391 struct buf *nbp; 2392 struct bufdomain *bd; 2393 2394 bd = &bdomain[bo->bo_domain]; 2395 if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh + 10) { 2396 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); 2397 altbufferflushes++; 2398 } else if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh) { 2399 BO_LOCK(bo); 2400 /* 2401 * Try to find a buffer to flush. 2402 */ 2403 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2404 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2405 BUF_LOCK(nbp, 2406 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2407 continue; 2408 if (bp == nbp) 2409 panic("bdwrite: found ourselves"); 2410 BO_UNLOCK(bo); 2411 /* Don't countdeps with the bo lock held. */ 2412 if (buf_countdeps(nbp, 0)) { 2413 BO_LOCK(bo); 2414 BUF_UNLOCK(nbp); 2415 continue; 2416 } 2417 if (nbp->b_flags & B_CLUSTEROK) { 2418 vfs_bio_awrite(nbp); 2419 } else { 2420 bremfree(nbp); 2421 bawrite(nbp); 2422 } 2423 dirtybufferflushes++; 2424 break; 2425 } 2426 if (nbp == NULL) 2427 BO_UNLOCK(bo); 2428 } 2429 } 2430 2431 /* 2432 * Delayed write. (Buffer is marked dirty). Do not bother writing 2433 * anything if the buffer is marked invalid. 2434 * 2435 * Note that since the buffer must be completely valid, we can safely 2436 * set B_CACHE. In fact, we have to set B_CACHE here rather then in 2437 * biodone() in order to prevent getblk from writing the buffer 2438 * out synchronously. 2439 */ 2440 void 2441 bdwrite(struct buf *bp) 2442 { 2443 struct thread *td = curthread; 2444 struct vnode *vp; 2445 struct bufobj *bo; 2446 2447 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2448 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2449 KASSERT((bp->b_flags & B_BARRIER) == 0, 2450 ("Barrier request in delayed write %p", bp)); 2451 2452 if (bp->b_flags & B_INVAL) { 2453 brelse(bp); 2454 return; 2455 } 2456 2457 /* 2458 * If we have too many dirty buffers, don't create any more. 2459 * If we are wildly over our limit, then force a complete 2460 * cleanup. Otherwise, just keep the situation from getting 2461 * out of control. Note that we have to avoid a recursive 2462 * disaster and not try to clean up after our own cleanup! 2463 */ 2464 vp = bp->b_vp; 2465 bo = bp->b_bufobj; 2466 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) { 2467 td->td_pflags |= TDP_INBDFLUSH; 2468 BO_BDFLUSH(bo, bp); 2469 td->td_pflags &= ~TDP_INBDFLUSH; 2470 } else 2471 recursiveflushes++; 2472 2473 bdirty(bp); 2474 /* 2475 * Set B_CACHE, indicating that the buffer is fully valid. This is 2476 * true even of NFS now. 2477 */ 2478 bp->b_flags |= B_CACHE; 2479 2480 /* 2481 * This bmap keeps the system from needing to do the bmap later, 2482 * perhaps when the system is attempting to do a sync. Since it 2483 * is likely that the indirect block -- or whatever other datastructure 2484 * that the filesystem needs is still in memory now, it is a good 2485 * thing to do this. Note also, that if the pageout daemon is 2486 * requesting a sync -- there might not be enough memory to do 2487 * the bmap then... So, this is important to do. 2488 */ 2489 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) { 2490 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 2491 } 2492 2493 buf_track(bp, __func__); 2494 2495 /* 2496 * Set the *dirty* buffer range based upon the VM system dirty 2497 * pages. 2498 * 2499 * Mark the buffer pages as clean. We need to do this here to 2500 * satisfy the vnode_pager and the pageout daemon, so that it 2501 * thinks that the pages have been "cleaned". Note that since 2502 * the pages are in a delayed write buffer -- the VFS layer 2503 * "will" see that the pages get written out on the next sync, 2504 * or perhaps the cluster will be completed. 2505 */ 2506 vfs_clean_pages_dirty_buf(bp); 2507 bqrelse(bp); 2508 2509 /* 2510 * note: we cannot initiate I/O from a bdwrite even if we wanted to, 2511 * due to the softdep code. 2512 */ 2513 } 2514 2515 /* 2516 * bdirty: 2517 * 2518 * Turn buffer into delayed write request. We must clear BIO_READ and 2519 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to 2520 * itself to properly update it in the dirty/clean lists. We mark it 2521 * B_DONE to ensure that any asynchronization of the buffer properly 2522 * clears B_DONE ( else a panic will occur later ). 2523 * 2524 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which 2525 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty() 2526 * should only be called if the buffer is known-good. 2527 * 2528 * Since the buffer is not on a queue, we do not update the numfreebuffers 2529 * count. 2530 * 2531 * The buffer must be on QUEUE_NONE. 2532 */ 2533 void 2534 bdirty(struct buf *bp) 2535 { 2536 2537 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X", 2538 bp, bp->b_vp, bp->b_flags); 2539 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2540 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2541 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2542 bp->b_flags &= ~(B_RELBUF); 2543 bp->b_iocmd = BIO_WRITE; 2544 2545 if ((bp->b_flags & B_DELWRI) == 0) { 2546 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI; 2547 reassignbuf(bp); 2548 bdirtyadd(bp); 2549 } 2550 } 2551 2552 /* 2553 * bundirty: 2554 * 2555 * Clear B_DELWRI for buffer. 2556 * 2557 * Since the buffer is not on a queue, we do not update the numfreebuffers 2558 * count. 2559 * 2560 * The buffer must be on QUEUE_NONE. 2561 */ 2562 2563 void 2564 bundirty(struct buf *bp) 2565 { 2566 2567 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2568 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2569 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2570 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2571 2572 if (bp->b_flags & B_DELWRI) { 2573 bp->b_flags &= ~B_DELWRI; 2574 reassignbuf(bp); 2575 bdirtysub(bp); 2576 } 2577 /* 2578 * Since it is now being written, we can clear its deferred write flag. 2579 */ 2580 bp->b_flags &= ~B_DEFERRED; 2581 } 2582 2583 /* 2584 * bawrite: 2585 * 2586 * Asynchronous write. Start output on a buffer, but do not wait for 2587 * it to complete. The buffer is released when the output completes. 2588 * 2589 * bwrite() ( or the VOP routine anyway ) is responsible for handling 2590 * B_INVAL buffers. Not us. 2591 */ 2592 void 2593 bawrite(struct buf *bp) 2594 { 2595 2596 bp->b_flags |= B_ASYNC; 2597 (void) bwrite(bp); 2598 } 2599 2600 /* 2601 * babarrierwrite: 2602 * 2603 * Asynchronous barrier write. Start output on a buffer, but do not 2604 * wait for it to complete. Place a write barrier after this write so 2605 * that this buffer and all buffers written before it are committed to 2606 * the disk before any buffers written after this write are committed 2607 * to the disk. The buffer is released when the output completes. 2608 */ 2609 void 2610 babarrierwrite(struct buf *bp) 2611 { 2612 2613 bp->b_flags |= B_ASYNC | B_BARRIER; 2614 (void) bwrite(bp); 2615 } 2616 2617 /* 2618 * bbarrierwrite: 2619 * 2620 * Synchronous barrier write. Start output on a buffer and wait for 2621 * it to complete. Place a write barrier after this write so that 2622 * this buffer and all buffers written before it are committed to 2623 * the disk before any buffers written after this write are committed 2624 * to the disk. The buffer is released when the output completes. 2625 */ 2626 int 2627 bbarrierwrite(struct buf *bp) 2628 { 2629 2630 bp->b_flags |= B_BARRIER; 2631 return (bwrite(bp)); 2632 } 2633 2634 /* 2635 * bwillwrite: 2636 * 2637 * Called prior to the locking of any vnodes when we are expecting to 2638 * write. We do not want to starve the buffer cache with too many 2639 * dirty buffers so we block here. By blocking prior to the locking 2640 * of any vnodes we attempt to avoid the situation where a locked vnode 2641 * prevents the various system daemons from flushing related buffers. 2642 */ 2643 void 2644 bwillwrite(void) 2645 { 2646 2647 if (buf_dirty_count_severe()) { 2648 mtx_lock(&bdirtylock); 2649 while (buf_dirty_count_severe()) { 2650 bdirtywait = 1; 2651 msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4), 2652 "flswai", 0); 2653 } 2654 mtx_unlock(&bdirtylock); 2655 } 2656 } 2657 2658 /* 2659 * Return true if we have too many dirty buffers. 2660 */ 2661 int 2662 buf_dirty_count_severe(void) 2663 { 2664 2665 return (!BIT_EMPTY(BUF_DOMAINS, &bdhidirty)); 2666 } 2667 2668 /* 2669 * brelse: 2670 * 2671 * Release a busy buffer and, if requested, free its resources. The 2672 * buffer will be stashed in the appropriate bufqueue[] allowing it 2673 * to be accessed later as a cache entity or reused for other purposes. 2674 */ 2675 void 2676 brelse(struct buf *bp) 2677 { 2678 struct mount *v_mnt; 2679 int qindex; 2680 2681 /* 2682 * Many functions erroneously call brelse with a NULL bp under rare 2683 * error conditions. Simply return when called with a NULL bp. 2684 */ 2685 if (bp == NULL) 2686 return; 2687 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X", 2688 bp, bp->b_vp, bp->b_flags); 2689 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2690 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2691 KASSERT((bp->b_flags & B_VMIO) != 0 || (bp->b_flags & B_NOREUSE) == 0, 2692 ("brelse: non-VMIO buffer marked NOREUSE")); 2693 2694 if (BUF_LOCKRECURSED(bp)) { 2695 /* 2696 * Do not process, in particular, do not handle the 2697 * B_INVAL/B_RELBUF and do not release to free list. 2698 */ 2699 BUF_UNLOCK(bp); 2700 return; 2701 } 2702 2703 if (bp->b_flags & B_MANAGED) { 2704 bqrelse(bp); 2705 return; 2706 } 2707 2708 if (LIST_EMPTY(&bp->b_dep)) { 2709 bp->b_flags &= ~B_IOSTARTED; 2710 } else { 2711 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2712 ("brelse: SU io not finished bp %p", bp)); 2713 } 2714 2715 if ((bp->b_vflags & (BV_BKGRDINPROG | BV_BKGRDERR)) == BV_BKGRDERR) { 2716 BO_LOCK(bp->b_bufobj); 2717 bp->b_vflags &= ~BV_BKGRDERR; 2718 BO_UNLOCK(bp->b_bufobj); 2719 bdirty(bp); 2720 } 2721 2722 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2723 (bp->b_flags & B_INVALONERR)) { 2724 /* 2725 * Forced invalidation of dirty buffer contents, to be used 2726 * after a failed write in the rare case that the loss of the 2727 * contents is acceptable. The buffer is invalidated and 2728 * freed. 2729 */ 2730 bp->b_flags |= B_INVAL | B_RELBUF | B_NOCACHE; 2731 bp->b_flags &= ~(B_ASYNC | B_CACHE); 2732 } 2733 2734 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2735 (bp->b_error != ENXIO || !LIST_EMPTY(&bp->b_dep)) && 2736 !(bp->b_flags & B_INVAL)) { 2737 /* 2738 * Failed write, redirty. All errors except ENXIO (which 2739 * means the device is gone) are treated as being 2740 * transient. 2741 * 2742 * XXX Treating EIO as transient is not correct; the 2743 * contract with the local storage device drivers is that 2744 * they will only return EIO once the I/O is no longer 2745 * retriable. Network I/O also respects this through the 2746 * guarantees of TCP and/or the internal retries of NFS. 2747 * ENOMEM might be transient, but we also have no way of 2748 * knowing when its ok to retry/reschedule. In general, 2749 * this entire case should be made obsolete through better 2750 * error handling/recovery and resource scheduling. 2751 * 2752 * Do this also for buffers that failed with ENXIO, but have 2753 * non-empty dependencies - the soft updates code might need 2754 * to access the buffer to untangle them. 2755 * 2756 * Must clear BIO_ERROR to prevent pages from being scrapped. 2757 */ 2758 bp->b_ioflags &= ~BIO_ERROR; 2759 bdirty(bp); 2760 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) || 2761 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) { 2762 /* 2763 * Either a failed read I/O, or we were asked to free or not 2764 * cache the buffer, or we failed to write to a device that's 2765 * no longer present. 2766 */ 2767 bp->b_flags |= B_INVAL; 2768 if (!LIST_EMPTY(&bp->b_dep)) 2769 buf_deallocate(bp); 2770 if (bp->b_flags & B_DELWRI) 2771 bdirtysub(bp); 2772 bp->b_flags &= ~(B_DELWRI | B_CACHE); 2773 if ((bp->b_flags & B_VMIO) == 0) { 2774 allocbuf(bp, 0); 2775 if (bp->b_vp) 2776 brelvp(bp); 2777 } 2778 } 2779 2780 /* 2781 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_truncate() 2782 * is called with B_DELWRI set, the underlying pages may wind up 2783 * getting freed causing a previous write (bdwrite()) to get 'lost' 2784 * because pages associated with a B_DELWRI bp are marked clean. 2785 * 2786 * We still allow the B_INVAL case to call vfs_vmio_truncate(), even 2787 * if B_DELWRI is set. 2788 */ 2789 if (bp->b_flags & B_DELWRI) 2790 bp->b_flags &= ~B_RELBUF; 2791 2792 /* 2793 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 2794 * constituted, not even NFS buffers now. Two flags effect this. If 2795 * B_INVAL, the struct buf is invalidated but the VM object is kept 2796 * around ( i.e. so it is trivial to reconstitute the buffer later ). 2797 * 2798 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be 2799 * invalidated. BIO_ERROR cannot be set for a failed write unless the 2800 * buffer is also B_INVAL because it hits the re-dirtying code above. 2801 * 2802 * Normally we can do this whether a buffer is B_DELWRI or not. If 2803 * the buffer is an NFS buffer, it is tracking piecemeal writes or 2804 * the commit state and we cannot afford to lose the buffer. If the 2805 * buffer has a background write in progress, we need to keep it 2806 * around to prevent it from being reconstituted and starting a second 2807 * background write. 2808 */ 2809 2810 v_mnt = bp->b_vp != NULL ? bp->b_vp->v_mount : NULL; 2811 2812 if ((bp->b_flags & B_VMIO) && (bp->b_flags & B_NOCACHE || 2813 (bp->b_ioflags & BIO_ERROR && bp->b_iocmd == BIO_READ)) && 2814 (v_mnt == NULL || (v_mnt->mnt_vfc->vfc_flags & VFCF_NETWORK) == 0 || 2815 vn_isdisk(bp->b_vp) || (bp->b_flags & B_DELWRI) == 0)) { 2816 vfs_vmio_invalidate(bp); 2817 allocbuf(bp, 0); 2818 } 2819 2820 if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0 || 2821 (bp->b_flags & (B_DELWRI | B_NOREUSE)) == B_NOREUSE) { 2822 allocbuf(bp, 0); 2823 bp->b_flags &= ~B_NOREUSE; 2824 if (bp->b_vp != NULL) 2825 brelvp(bp); 2826 } 2827 2828 /* 2829 * If the buffer has junk contents signal it and eventually 2830 * clean up B_DELWRI and diassociate the vnode so that gbincore() 2831 * doesn't find it. 2832 */ 2833 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 || 2834 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0) 2835 bp->b_flags |= B_INVAL; 2836 if (bp->b_flags & B_INVAL) { 2837 if (bp->b_flags & B_DELWRI) 2838 bundirty(bp); 2839 if (bp->b_vp) 2840 brelvp(bp); 2841 } 2842 2843 buf_track(bp, __func__); 2844 2845 /* buffers with no memory */ 2846 if (bp->b_bufsize == 0) { 2847 buf_free(bp); 2848 return; 2849 } 2850 /* buffers with junk contents */ 2851 if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) || 2852 (bp->b_ioflags & BIO_ERROR)) { 2853 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 2854 if (bp->b_vflags & BV_BKGRDINPROG) 2855 panic("losing buffer 2"); 2856 qindex = QUEUE_CLEAN; 2857 bp->b_flags |= B_AGE; 2858 /* remaining buffers */ 2859 } else if (bp->b_flags & B_DELWRI) 2860 qindex = QUEUE_DIRTY; 2861 else 2862 qindex = QUEUE_CLEAN; 2863 2864 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) 2865 panic("brelse: not dirty"); 2866 2867 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_RELBUF | B_DIRECT); 2868 bp->b_xflags &= ~(BX_CVTENXIO); 2869 /* binsfree unlocks bp. */ 2870 binsfree(bp, qindex); 2871 } 2872 2873 /* 2874 * Release a buffer back to the appropriate queue but do not try to free 2875 * it. The buffer is expected to be used again soon. 2876 * 2877 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by 2878 * biodone() to requeue an async I/O on completion. It is also used when 2879 * known good buffers need to be requeued but we think we may need the data 2880 * again soon. 2881 * 2882 * XXX we should be able to leave the B_RELBUF hint set on completion. 2883 */ 2884 void 2885 bqrelse(struct buf *bp) 2886 { 2887 int qindex; 2888 2889 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2890 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2891 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2892 2893 qindex = QUEUE_NONE; 2894 if (BUF_LOCKRECURSED(bp)) { 2895 /* do not release to free list */ 2896 BUF_UNLOCK(bp); 2897 return; 2898 } 2899 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 2900 bp->b_xflags &= ~(BX_CVTENXIO); 2901 2902 if (LIST_EMPTY(&bp->b_dep)) { 2903 bp->b_flags &= ~B_IOSTARTED; 2904 } else { 2905 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2906 ("bqrelse: SU io not finished bp %p", bp)); 2907 } 2908 2909 if (bp->b_flags & B_MANAGED) { 2910 if (bp->b_flags & B_REMFREE) 2911 bremfreef(bp); 2912 goto out; 2913 } 2914 2915 /* buffers with stale but valid contents */ 2916 if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG | 2917 BV_BKGRDERR)) == BV_BKGRDERR) { 2918 BO_LOCK(bp->b_bufobj); 2919 bp->b_vflags &= ~BV_BKGRDERR; 2920 BO_UNLOCK(bp->b_bufobj); 2921 qindex = QUEUE_DIRTY; 2922 } else { 2923 if ((bp->b_flags & B_DELWRI) == 0 && 2924 (bp->b_xflags & BX_VNDIRTY)) 2925 panic("bqrelse: not dirty"); 2926 if ((bp->b_flags & B_NOREUSE) != 0) { 2927 brelse(bp); 2928 return; 2929 } 2930 qindex = QUEUE_CLEAN; 2931 } 2932 buf_track(bp, __func__); 2933 /* binsfree unlocks bp. */ 2934 binsfree(bp, qindex); 2935 return; 2936 2937 out: 2938 buf_track(bp, __func__); 2939 /* unlock */ 2940 BUF_UNLOCK(bp); 2941 } 2942 2943 /* 2944 * Complete I/O to a VMIO backed page. Validate the pages as appropriate, 2945 * restore bogus pages. 2946 */ 2947 static void 2948 vfs_vmio_iodone(struct buf *bp) 2949 { 2950 vm_ooffset_t foff; 2951 vm_page_t m; 2952 vm_object_t obj; 2953 struct vnode *vp __unused; 2954 int i, iosize, resid; 2955 bool bogus; 2956 2957 obj = bp->b_bufobj->bo_object; 2958 KASSERT(blockcount_read(&obj->paging_in_progress) >= bp->b_npages, 2959 ("vfs_vmio_iodone: paging in progress(%d) < b_npages(%d)", 2960 blockcount_read(&obj->paging_in_progress), bp->b_npages)); 2961 2962 vp = bp->b_vp; 2963 VNPASS(vp->v_holdcnt > 0, vp); 2964 VNPASS(vp->v_object != NULL, vp); 2965 2966 foff = bp->b_offset; 2967 KASSERT(bp->b_offset != NOOFFSET, 2968 ("vfs_vmio_iodone: bp %p has no buffer offset", bp)); 2969 2970 bogus = false; 2971 iosize = bp->b_bcount - bp->b_resid; 2972 for (i = 0; i < bp->b_npages; i++) { 2973 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff; 2974 if (resid > iosize) 2975 resid = iosize; 2976 2977 /* 2978 * cleanup bogus pages, restoring the originals 2979 */ 2980 m = bp->b_pages[i]; 2981 if (m == bogus_page) { 2982 bogus = true; 2983 m = vm_page_relookup(obj, OFF_TO_IDX(foff)); 2984 if (m == NULL) 2985 panic("biodone: page disappeared!"); 2986 bp->b_pages[i] = m; 2987 } else if ((bp->b_iocmd == BIO_READ) && resid > 0) { 2988 /* 2989 * In the write case, the valid and clean bits are 2990 * already changed correctly ( see bdwrite() ), so we 2991 * only need to do this here in the read case. 2992 */ 2993 KASSERT((m->dirty & vm_page_bits(foff & PAGE_MASK, 2994 resid)) == 0, ("vfs_vmio_iodone: page %p " 2995 "has unexpected dirty bits", m)); 2996 vfs_page_set_valid(bp, foff, m); 2997 } 2998 KASSERT(OFF_TO_IDX(foff) == m->pindex, 2999 ("vfs_vmio_iodone: foff(%jd)/pindex(%ju) mismatch", 3000 (intmax_t)foff, (uintmax_t)m->pindex)); 3001 3002 vm_page_sunbusy(m); 3003 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3004 iosize -= resid; 3005 } 3006 vm_object_pip_wakeupn(obj, bp->b_npages); 3007 if (bogus && buf_mapped(bp)) { 3008 BUF_CHECK_MAPPED(bp); 3009 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 3010 bp->b_pages, bp->b_npages); 3011 } 3012 } 3013 3014 /* 3015 * Perform page invalidation when a buffer is released. The fully invalid 3016 * pages will be reclaimed later in vfs_vmio_truncate(). 3017 */ 3018 static void 3019 vfs_vmio_invalidate(struct buf *bp) 3020 { 3021 vm_object_t obj; 3022 vm_page_t m; 3023 int flags, i, resid, poffset, presid; 3024 3025 if (buf_mapped(bp)) { 3026 BUF_CHECK_MAPPED(bp); 3027 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages); 3028 } else 3029 BUF_CHECK_UNMAPPED(bp); 3030 /* 3031 * Get the base offset and length of the buffer. Note that 3032 * in the VMIO case if the buffer block size is not 3033 * page-aligned then b_data pointer may not be page-aligned. 3034 * But our b_pages[] array *IS* page aligned. 3035 * 3036 * block sizes less then DEV_BSIZE (usually 512) are not 3037 * supported due to the page granularity bits (m->valid, 3038 * m->dirty, etc...). 3039 * 3040 * See man buf(9) for more information 3041 */ 3042 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3043 obj = bp->b_bufobj->bo_object; 3044 resid = bp->b_bufsize; 3045 poffset = bp->b_offset & PAGE_MASK; 3046 VM_OBJECT_WLOCK(obj); 3047 for (i = 0; i < bp->b_npages; i++) { 3048 m = bp->b_pages[i]; 3049 if (m == bogus_page) 3050 panic("vfs_vmio_invalidate: Unexpected bogus page."); 3051 bp->b_pages[i] = NULL; 3052 3053 presid = resid > (PAGE_SIZE - poffset) ? 3054 (PAGE_SIZE - poffset) : resid; 3055 KASSERT(presid >= 0, ("brelse: extra page")); 3056 vm_page_busy_acquire(m, VM_ALLOC_SBUSY); 3057 if (pmap_page_wired_mappings(m) == 0) 3058 vm_page_set_invalid(m, poffset, presid); 3059 vm_page_sunbusy(m); 3060 vm_page_release_locked(m, flags); 3061 resid -= presid; 3062 poffset = 0; 3063 } 3064 VM_OBJECT_WUNLOCK(obj); 3065 bp->b_npages = 0; 3066 } 3067 3068 /* 3069 * Page-granular truncation of an existing VMIO buffer. 3070 */ 3071 static void 3072 vfs_vmio_truncate(struct buf *bp, int desiredpages) 3073 { 3074 vm_object_t obj; 3075 vm_page_t m; 3076 int flags, i; 3077 3078 if (bp->b_npages == desiredpages) 3079 return; 3080 3081 if (buf_mapped(bp)) { 3082 BUF_CHECK_MAPPED(bp); 3083 pmap_qremove((vm_offset_t)trunc_page((vm_offset_t)bp->b_data) + 3084 (desiredpages << PAGE_SHIFT), bp->b_npages - desiredpages); 3085 } else 3086 BUF_CHECK_UNMAPPED(bp); 3087 3088 /* 3089 * The object lock is needed only if we will attempt to free pages. 3090 */ 3091 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3092 if ((bp->b_flags & B_DIRECT) != 0) { 3093 flags |= VPR_TRYFREE; 3094 obj = bp->b_bufobj->bo_object; 3095 VM_OBJECT_WLOCK(obj); 3096 } else { 3097 obj = NULL; 3098 } 3099 for (i = desiredpages; i < bp->b_npages; i++) { 3100 m = bp->b_pages[i]; 3101 KASSERT(m != bogus_page, ("allocbuf: bogus page found")); 3102 bp->b_pages[i] = NULL; 3103 if (obj != NULL) 3104 vm_page_release_locked(m, flags); 3105 else 3106 vm_page_release(m, flags); 3107 } 3108 if (obj != NULL) 3109 VM_OBJECT_WUNLOCK(obj); 3110 bp->b_npages = desiredpages; 3111 } 3112 3113 /* 3114 * Byte granular extension of VMIO buffers. 3115 */ 3116 static void 3117 vfs_vmio_extend(struct buf *bp, int desiredpages, int size) 3118 { 3119 /* 3120 * We are growing the buffer, possibly in a 3121 * byte-granular fashion. 3122 */ 3123 vm_object_t obj; 3124 vm_offset_t toff; 3125 vm_offset_t tinc; 3126 vm_page_t m; 3127 3128 /* 3129 * Step 1, bring in the VM pages from the object, allocating 3130 * them if necessary. We must clear B_CACHE if these pages 3131 * are not valid for the range covered by the buffer. 3132 */ 3133 obj = bp->b_bufobj->bo_object; 3134 if (bp->b_npages < desiredpages) { 3135 KASSERT(desiredpages <= atop(maxbcachebuf), 3136 ("vfs_vmio_extend past maxbcachebuf %p %d %u", 3137 bp, desiredpages, maxbcachebuf)); 3138 3139 /* 3140 * We must allocate system pages since blocking 3141 * here could interfere with paging I/O, no 3142 * matter which process we are. 3143 * 3144 * Only exclusive busy can be tested here. 3145 * Blocking on shared busy might lead to 3146 * deadlocks once allocbuf() is called after 3147 * pages are vfs_busy_pages(). 3148 */ 3149 (void)vm_page_grab_pages_unlocked(obj, 3150 OFF_TO_IDX(bp->b_offset) + bp->b_npages, 3151 VM_ALLOC_SYSTEM | VM_ALLOC_IGN_SBUSY | 3152 VM_ALLOC_NOBUSY | VM_ALLOC_WIRED, 3153 &bp->b_pages[bp->b_npages], desiredpages - bp->b_npages); 3154 bp->b_npages = desiredpages; 3155 } 3156 3157 /* 3158 * Step 2. We've loaded the pages into the buffer, 3159 * we have to figure out if we can still have B_CACHE 3160 * set. Note that B_CACHE is set according to the 3161 * byte-granular range ( bcount and size ), not the 3162 * aligned range ( newbsize ). 3163 * 3164 * The VM test is against m->valid, which is DEV_BSIZE 3165 * aligned. Needless to say, the validity of the data 3166 * needs to also be DEV_BSIZE aligned. Note that this 3167 * fails with NFS if the server or some other client 3168 * extends the file's EOF. If our buffer is resized, 3169 * B_CACHE may remain set! XXX 3170 */ 3171 toff = bp->b_bcount; 3172 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK); 3173 while ((bp->b_flags & B_CACHE) && toff < size) { 3174 vm_pindex_t pi; 3175 3176 if (tinc > (size - toff)) 3177 tinc = size - toff; 3178 pi = ((bp->b_offset & PAGE_MASK) + toff) >> PAGE_SHIFT; 3179 m = bp->b_pages[pi]; 3180 vfs_buf_test_cache(bp, bp->b_offset, toff, tinc, m); 3181 toff += tinc; 3182 tinc = PAGE_SIZE; 3183 } 3184 3185 /* 3186 * Step 3, fixup the KVA pmap. 3187 */ 3188 if (buf_mapped(bp)) 3189 bpmap_qenter(bp); 3190 else 3191 BUF_CHECK_UNMAPPED(bp); 3192 } 3193 3194 /* 3195 * Check to see if a block at a particular lbn is available for a clustered 3196 * write. 3197 */ 3198 static int 3199 vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno) 3200 { 3201 struct buf *bpa; 3202 int match; 3203 3204 match = 0; 3205 3206 /* If the buf isn't in core skip it */ 3207 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL) 3208 return (0); 3209 3210 /* If the buf is busy we don't want to wait for it */ 3211 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 3212 return (0); 3213 3214 /* Only cluster with valid clusterable delayed write buffers */ 3215 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) != 3216 (B_DELWRI | B_CLUSTEROK)) 3217 goto done; 3218 3219 if (bpa->b_bufsize != size) 3220 goto done; 3221 3222 /* 3223 * Check to see if it is in the expected place on disk and that the 3224 * block has been mapped. 3225 */ 3226 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno)) 3227 match = 1; 3228 done: 3229 BUF_UNLOCK(bpa); 3230 return (match); 3231 } 3232 3233 /* 3234 * vfs_bio_awrite: 3235 * 3236 * Implement clustered async writes for clearing out B_DELWRI buffers. 3237 * This is much better then the old way of writing only one buffer at 3238 * a time. Note that we may not be presented with the buffers in the 3239 * correct order, so we search for the cluster in both directions. 3240 */ 3241 int 3242 vfs_bio_awrite(struct buf *bp) 3243 { 3244 struct bufobj *bo; 3245 int i; 3246 int j; 3247 daddr_t lblkno = bp->b_lblkno; 3248 struct vnode *vp = bp->b_vp; 3249 int ncl; 3250 int nwritten; 3251 int size; 3252 int maxcl; 3253 int gbflags; 3254 3255 bo = &vp->v_bufobj; 3256 gbflags = (bp->b_data == unmapped_buf) ? GB_UNMAPPED : 0; 3257 /* 3258 * right now we support clustered writing only to regular files. If 3259 * we find a clusterable block we could be in the middle of a cluster 3260 * rather then at the beginning. 3261 */ 3262 if ((vp->v_type == VREG) && 3263 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 3264 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 3265 size = vp->v_mount->mnt_stat.f_iosize; 3266 maxcl = maxphys / size; 3267 3268 BO_RLOCK(bo); 3269 for (i = 1; i < maxcl; i++) 3270 if (vfs_bio_clcheck(vp, size, lblkno + i, 3271 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0) 3272 break; 3273 3274 for (j = 1; i + j <= maxcl && j <= lblkno; j++) 3275 if (vfs_bio_clcheck(vp, size, lblkno - j, 3276 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0) 3277 break; 3278 BO_RUNLOCK(bo); 3279 --j; 3280 ncl = i + j; 3281 /* 3282 * this is a possible cluster write 3283 */ 3284 if (ncl != 1) { 3285 BUF_UNLOCK(bp); 3286 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, 3287 gbflags); 3288 return (nwritten); 3289 } 3290 } 3291 bremfree(bp); 3292 bp->b_flags |= B_ASYNC; 3293 /* 3294 * default (old) behavior, writing out only one block 3295 * 3296 * XXX returns b_bufsize instead of b_bcount for nwritten? 3297 */ 3298 nwritten = bp->b_bufsize; 3299 (void) bwrite(bp); 3300 3301 return (nwritten); 3302 } 3303 3304 /* 3305 * getnewbuf_kva: 3306 * 3307 * Allocate KVA for an empty buf header according to gbflags. 3308 */ 3309 static int 3310 getnewbuf_kva(struct buf *bp, int gbflags, int maxsize) 3311 { 3312 3313 if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_UNMAPPED) { 3314 /* 3315 * In order to keep fragmentation sane we only allocate kva 3316 * in BKVASIZE chunks. XXX with vmem we can do page size. 3317 */ 3318 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK; 3319 3320 if (maxsize != bp->b_kvasize && 3321 bufkva_alloc(bp, maxsize, gbflags)) 3322 return (ENOSPC); 3323 } 3324 return (0); 3325 } 3326 3327 /* 3328 * getnewbuf: 3329 * 3330 * Find and initialize a new buffer header, freeing up existing buffers 3331 * in the bufqueues as necessary. The new buffer is returned locked. 3332 * 3333 * We block if: 3334 * We have insufficient buffer headers 3335 * We have insufficient buffer space 3336 * buffer_arena is too fragmented ( space reservation fails ) 3337 * If we have to flush dirty buffers ( but we try to avoid this ) 3338 * 3339 * The caller is responsible for releasing the reserved bufspace after 3340 * allocbuf() is called. 3341 */ 3342 static struct buf * 3343 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int maxsize, int gbflags) 3344 { 3345 struct bufdomain *bd; 3346 struct buf *bp; 3347 bool metadata, reserved; 3348 3349 bp = NULL; 3350 KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3351 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3352 if (!unmapped_buf_allowed) 3353 gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3354 3355 if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 || 3356 vp->v_type == VCHR) 3357 metadata = true; 3358 else 3359 metadata = false; 3360 if (vp == NULL) 3361 bd = &bdomain[0]; 3362 else 3363 bd = &bdomain[vp->v_bufobj.bo_domain]; 3364 3365 counter_u64_add(getnewbufcalls, 1); 3366 reserved = false; 3367 do { 3368 if (reserved == false && 3369 bufspace_reserve(bd, maxsize, metadata) != 0) { 3370 counter_u64_add(getnewbufrestarts, 1); 3371 continue; 3372 } 3373 reserved = true; 3374 if ((bp = buf_alloc(bd)) == NULL) { 3375 counter_u64_add(getnewbufrestarts, 1); 3376 continue; 3377 } 3378 if (getnewbuf_kva(bp, gbflags, maxsize) == 0) 3379 return (bp); 3380 break; 3381 } while (buf_recycle(bd, false) == 0); 3382 3383 if (reserved) 3384 bufspace_release(bd, maxsize); 3385 if (bp != NULL) { 3386 bp->b_flags |= B_INVAL; 3387 brelse(bp); 3388 } 3389 bufspace_wait(bd, vp, gbflags, slpflag, slptimeo); 3390 3391 return (NULL); 3392 } 3393 3394 /* 3395 * buf_daemon: 3396 * 3397 * buffer flushing daemon. Buffers are normally flushed by the 3398 * update daemon but if it cannot keep up this process starts to 3399 * take the load in an attempt to prevent getnewbuf() from blocking. 3400 */ 3401 static struct kproc_desc buf_kp = { 3402 "bufdaemon", 3403 buf_daemon, 3404 &bufdaemonproc 3405 }; 3406 SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp); 3407 3408 static int 3409 buf_flush(struct vnode *vp, struct bufdomain *bd, int target) 3410 { 3411 int flushed; 3412 3413 flushed = flushbufqueues(vp, bd, target, 0); 3414 if (flushed == 0) { 3415 /* 3416 * Could not find any buffers without rollback 3417 * dependencies, so just write the first one 3418 * in the hopes of eventually making progress. 3419 */ 3420 if (vp != NULL && target > 2) 3421 target /= 2; 3422 flushbufqueues(vp, bd, target, 1); 3423 } 3424 return (flushed); 3425 } 3426 3427 static void 3428 buf_daemon_shutdown(void *arg __unused, int howto __unused) 3429 { 3430 int error; 3431 3432 if (KERNEL_PANICKED()) 3433 return; 3434 3435 mtx_lock(&bdlock); 3436 bd_shutdown = true; 3437 wakeup(&bd_request); 3438 error = msleep(&bd_shutdown, &bdlock, 0, "buf_daemon_shutdown", 3439 60 * hz); 3440 mtx_unlock(&bdlock); 3441 if (error != 0) 3442 printf("bufdaemon wait error: %d\n", error); 3443 } 3444 3445 static void 3446 buf_daemon(void) 3447 { 3448 struct bufdomain *bd; 3449 int speedupreq; 3450 int lodirty; 3451 int i; 3452 3453 /* 3454 * This process needs to be suspended prior to shutdown sync. 3455 */ 3456 EVENTHANDLER_REGISTER(shutdown_pre_sync, buf_daemon_shutdown, NULL, 3457 SHUTDOWN_PRI_LAST + 100); 3458 3459 /* 3460 * Start the buf clean daemons as children threads. 3461 */ 3462 for (i = 0 ; i < buf_domains; i++) { 3463 int error; 3464 3465 error = kthread_add((void (*)(void *))bufspace_daemon, 3466 &bdomain[i], curproc, NULL, 0, 0, "bufspacedaemon-%d", i); 3467 if (error) 3468 panic("error %d spawning bufspace daemon", error); 3469 } 3470 3471 /* 3472 * This process is allowed to take the buffer cache to the limit 3473 */ 3474 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED; 3475 mtx_lock(&bdlock); 3476 while (!bd_shutdown) { 3477 bd_request = 0; 3478 mtx_unlock(&bdlock); 3479 3480 /* 3481 * Save speedupreq for this pass and reset to capture new 3482 * requests. 3483 */ 3484 speedupreq = bd_speedupreq; 3485 bd_speedupreq = 0; 3486 3487 /* 3488 * Flush each domain sequentially according to its level and 3489 * the speedup request. 3490 */ 3491 for (i = 0; i < buf_domains; i++) { 3492 bd = &bdomain[i]; 3493 if (speedupreq) 3494 lodirty = bd->bd_numdirtybuffers / 2; 3495 else 3496 lodirty = bd->bd_lodirtybuffers; 3497 while (bd->bd_numdirtybuffers > lodirty) { 3498 if (buf_flush(NULL, bd, 3499 bd->bd_numdirtybuffers - lodirty) == 0) 3500 break; 3501 kern_yield(PRI_USER); 3502 } 3503 } 3504 3505 /* 3506 * Only clear bd_request if we have reached our low water 3507 * mark. The buf_daemon normally waits 1 second and 3508 * then incrementally flushes any dirty buffers that have 3509 * built up, within reason. 3510 * 3511 * If we were unable to hit our low water mark and couldn't 3512 * find any flushable buffers, we sleep for a short period 3513 * to avoid endless loops on unlockable buffers. 3514 */ 3515 mtx_lock(&bdlock); 3516 if (bd_shutdown) 3517 break; 3518 if (BIT_EMPTY(BUF_DOMAINS, &bdlodirty)) { 3519 /* 3520 * We reached our low water mark, reset the 3521 * request and sleep until we are needed again. 3522 * The sleep is just so the suspend code works. 3523 */ 3524 bd_request = 0; 3525 /* 3526 * Do an extra wakeup in case dirty threshold 3527 * changed via sysctl and the explicit transition 3528 * out of shortfall was missed. 3529 */ 3530 bdirtywakeup(); 3531 if (runningbufspace <= lorunningspace) 3532 runningwakeup(); 3533 msleep(&bd_request, &bdlock, PVM, "psleep", hz); 3534 } else { 3535 /* 3536 * We couldn't find any flushable dirty buffers but 3537 * still have too many dirty buffers, we 3538 * have to sleep and try again. (rare) 3539 */ 3540 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10); 3541 } 3542 } 3543 wakeup(&bd_shutdown); 3544 mtx_unlock(&bdlock); 3545 kthread_exit(); 3546 } 3547 3548 /* 3549 * flushbufqueues: 3550 * 3551 * Try to flush a buffer in the dirty queue. We must be careful to 3552 * free up B_INVAL buffers instead of write them, which NFS is 3553 * particularly sensitive to. 3554 */ 3555 static int flushwithdeps = 0; 3556 SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW | CTLFLAG_STATS, 3557 &flushwithdeps, 0, 3558 "Number of buffers flushed with dependencies that require rollbacks"); 3559 3560 static int 3561 flushbufqueues(struct vnode *lvp, struct bufdomain *bd, int target, 3562 int flushdeps) 3563 { 3564 struct bufqueue *bq; 3565 struct buf *sentinel; 3566 struct vnode *vp; 3567 struct mount *mp; 3568 struct buf *bp; 3569 int hasdeps; 3570 int flushed; 3571 int error; 3572 bool unlock; 3573 3574 flushed = 0; 3575 bq = &bd->bd_dirtyq; 3576 bp = NULL; 3577 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO); 3578 sentinel->b_qindex = QUEUE_SENTINEL; 3579 BQ_LOCK(bq); 3580 TAILQ_INSERT_HEAD(&bq->bq_queue, sentinel, b_freelist); 3581 BQ_UNLOCK(bq); 3582 while (flushed != target) { 3583 maybe_yield(); 3584 BQ_LOCK(bq); 3585 bp = TAILQ_NEXT(sentinel, b_freelist); 3586 if (bp != NULL) { 3587 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3588 TAILQ_INSERT_AFTER(&bq->bq_queue, bp, sentinel, 3589 b_freelist); 3590 } else { 3591 BQ_UNLOCK(bq); 3592 break; 3593 } 3594 /* 3595 * Skip sentinels inserted by other invocations of the 3596 * flushbufqueues(), taking care to not reorder them. 3597 * 3598 * Only flush the buffers that belong to the 3599 * vnode locked by the curthread. 3600 */ 3601 if (bp->b_qindex == QUEUE_SENTINEL || (lvp != NULL && 3602 bp->b_vp != lvp)) { 3603 BQ_UNLOCK(bq); 3604 continue; 3605 } 3606 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 3607 BQ_UNLOCK(bq); 3608 if (error != 0) 3609 continue; 3610 3611 /* 3612 * BKGRDINPROG can only be set with the buf and bufobj 3613 * locks both held. We tolerate a race to clear it here. 3614 */ 3615 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 || 3616 (bp->b_flags & B_DELWRI) == 0) { 3617 BUF_UNLOCK(bp); 3618 continue; 3619 } 3620 if (bp->b_flags & B_INVAL) { 3621 bremfreef(bp); 3622 brelse(bp); 3623 flushed++; 3624 continue; 3625 } 3626 3627 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) { 3628 if (flushdeps == 0) { 3629 BUF_UNLOCK(bp); 3630 continue; 3631 } 3632 hasdeps = 1; 3633 } else 3634 hasdeps = 0; 3635 /* 3636 * We must hold the lock on a vnode before writing 3637 * one of its buffers. Otherwise we may confuse, or 3638 * in the case of a snapshot vnode, deadlock the 3639 * system. 3640 * 3641 * The lock order here is the reverse of the normal 3642 * of vnode followed by buf lock. This is ok because 3643 * the NOWAIT will prevent deadlock. 3644 */ 3645 vp = bp->b_vp; 3646 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { 3647 BUF_UNLOCK(bp); 3648 continue; 3649 } 3650 if (lvp == NULL) { 3651 unlock = true; 3652 error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); 3653 } else { 3654 ASSERT_VOP_LOCKED(vp, "getbuf"); 3655 unlock = false; 3656 error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : 3657 vn_lock(vp, LK_TRYUPGRADE); 3658 } 3659 if (error == 0) { 3660 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", 3661 bp, bp->b_vp, bp->b_flags); 3662 if (curproc == bufdaemonproc) { 3663 vfs_bio_awrite(bp); 3664 } else { 3665 bremfree(bp); 3666 bwrite(bp); 3667 counter_u64_add(notbufdflushes, 1); 3668 } 3669 vn_finished_write(mp); 3670 if (unlock) 3671 VOP_UNLOCK(vp); 3672 flushwithdeps += hasdeps; 3673 flushed++; 3674 3675 /* 3676 * Sleeping on runningbufspace while holding 3677 * vnode lock leads to deadlock. 3678 */ 3679 if (curproc == bufdaemonproc && 3680 runningbufspace > hirunningspace) 3681 waitrunningbufspace(); 3682 continue; 3683 } 3684 vn_finished_write(mp); 3685 BUF_UNLOCK(bp); 3686 } 3687 BQ_LOCK(bq); 3688 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3689 BQ_UNLOCK(bq); 3690 free(sentinel, M_TEMP); 3691 return (flushed); 3692 } 3693 3694 /* 3695 * Check to see if a block is currently memory resident. 3696 */ 3697 struct buf * 3698 incore(struct bufobj *bo, daddr_t blkno) 3699 { 3700 return (gbincore_unlocked(bo, blkno)); 3701 } 3702 3703 /* 3704 * Returns true if no I/O is needed to access the 3705 * associated VM object. This is like incore except 3706 * it also hunts around in the VM system for the data. 3707 */ 3708 bool 3709 inmem(struct vnode * vp, daddr_t blkno) 3710 { 3711 vm_object_t obj; 3712 vm_offset_t toff, tinc, size; 3713 vm_page_t m, n; 3714 vm_ooffset_t off; 3715 int valid; 3716 3717 ASSERT_VOP_LOCKED(vp, "inmem"); 3718 3719 if (incore(&vp->v_bufobj, blkno)) 3720 return (true); 3721 if (vp->v_mount == NULL) 3722 return (false); 3723 obj = vp->v_object; 3724 if (obj == NULL) 3725 return (false); 3726 3727 size = PAGE_SIZE; 3728 if (size > vp->v_mount->mnt_stat.f_iosize) 3729 size = vp->v_mount->mnt_stat.f_iosize; 3730 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 3731 3732 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 3733 m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3734 recheck: 3735 if (m == NULL) 3736 return (false); 3737 3738 tinc = size; 3739 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 3740 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 3741 /* 3742 * Consider page validity only if page mapping didn't change 3743 * during the check. 3744 */ 3745 valid = vm_page_is_valid(m, 3746 (vm_offset_t)((toff + off) & PAGE_MASK), tinc); 3747 n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3748 if (m != n) { 3749 m = n; 3750 goto recheck; 3751 } 3752 if (!valid) 3753 return (false); 3754 } 3755 return (true); 3756 } 3757 3758 /* 3759 * Set the dirty range for a buffer based on the status of the dirty 3760 * bits in the pages comprising the buffer. The range is limited 3761 * to the size of the buffer. 3762 * 3763 * Tell the VM system that the pages associated with this buffer 3764 * are clean. This is used for delayed writes where the data is 3765 * going to go to disk eventually without additional VM intevention. 3766 * 3767 * Note that while we only really need to clean through to b_bcount, we 3768 * just go ahead and clean through to b_bufsize. 3769 */ 3770 static void 3771 vfs_clean_pages_dirty_buf(struct buf *bp) 3772 { 3773 vm_ooffset_t foff, noff, eoff; 3774 vm_page_t m; 3775 int i; 3776 3777 if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0) 3778 return; 3779 3780 foff = bp->b_offset; 3781 KASSERT(bp->b_offset != NOOFFSET, 3782 ("vfs_clean_pages_dirty_buf: no buffer offset")); 3783 3784 vfs_busy_pages_acquire(bp); 3785 vfs_setdirty_range(bp); 3786 for (i = 0; i < bp->b_npages; i++) { 3787 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3788 eoff = noff; 3789 if (eoff > bp->b_offset + bp->b_bufsize) 3790 eoff = bp->b_offset + bp->b_bufsize; 3791 m = bp->b_pages[i]; 3792 vfs_page_set_validclean(bp, foff, m); 3793 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */ 3794 foff = noff; 3795 } 3796 vfs_busy_pages_release(bp); 3797 } 3798 3799 static void 3800 vfs_setdirty_range(struct buf *bp) 3801 { 3802 vm_offset_t boffset; 3803 vm_offset_t eoffset; 3804 int i; 3805 3806 /* 3807 * test the pages to see if they have been modified directly 3808 * by users through the VM system. 3809 */ 3810 for (i = 0; i < bp->b_npages; i++) 3811 vm_page_test_dirty(bp->b_pages[i]); 3812 3813 /* 3814 * Calculate the encompassing dirty range, boffset and eoffset, 3815 * (eoffset - boffset) bytes. 3816 */ 3817 3818 for (i = 0; i < bp->b_npages; i++) { 3819 if (bp->b_pages[i]->dirty) 3820 break; 3821 } 3822 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3823 3824 for (i = bp->b_npages - 1; i >= 0; --i) { 3825 if (bp->b_pages[i]->dirty) { 3826 break; 3827 } 3828 } 3829 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3830 3831 /* 3832 * Fit it to the buffer. 3833 */ 3834 3835 if (eoffset > bp->b_bcount) 3836 eoffset = bp->b_bcount; 3837 3838 /* 3839 * If we have a good dirty range, merge with the existing 3840 * dirty range. 3841 */ 3842 3843 if (boffset < eoffset) { 3844 if (bp->b_dirtyoff > boffset) 3845 bp->b_dirtyoff = boffset; 3846 if (bp->b_dirtyend < eoffset) 3847 bp->b_dirtyend = eoffset; 3848 } 3849 } 3850 3851 /* 3852 * Allocate the KVA mapping for an existing buffer. 3853 * If an unmapped buffer is provided but a mapped buffer is requested, take 3854 * also care to properly setup mappings between pages and KVA. 3855 */ 3856 static void 3857 bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags) 3858 { 3859 int bsize, maxsize, need_mapping, need_kva; 3860 off_t offset; 3861 3862 need_mapping = bp->b_data == unmapped_buf && 3863 (gbflags & GB_UNMAPPED) == 0; 3864 need_kva = bp->b_kvabase == unmapped_buf && 3865 bp->b_data == unmapped_buf && 3866 (gbflags & GB_KVAALLOC) != 0; 3867 if (!need_mapping && !need_kva) 3868 return; 3869 3870 BUF_CHECK_UNMAPPED(bp); 3871 3872 if (need_mapping && bp->b_kvabase != unmapped_buf) { 3873 /* 3874 * Buffer is not mapped, but the KVA was already 3875 * reserved at the time of the instantiation. Use the 3876 * allocated space. 3877 */ 3878 goto has_addr; 3879 } 3880 3881 /* 3882 * Calculate the amount of the address space we would reserve 3883 * if the buffer was mapped. 3884 */ 3885 bsize = vn_isdisk(bp->b_vp) ? DEV_BSIZE : bp->b_bufobj->bo_bsize; 3886 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 3887 offset = blkno * bsize; 3888 maxsize = size + (offset & PAGE_MASK); 3889 maxsize = imax(maxsize, bsize); 3890 3891 while (bufkva_alloc(bp, maxsize, gbflags) != 0) { 3892 if ((gbflags & GB_NOWAIT_BD) != 0) { 3893 /* 3894 * XXXKIB: defragmentation cannot 3895 * succeed, not sure what else to do. 3896 */ 3897 panic("GB_NOWAIT_BD and GB_UNMAPPED %p", bp); 3898 } 3899 counter_u64_add(mappingrestarts, 1); 3900 bufspace_wait(bufdomain(bp), bp->b_vp, gbflags, 0, 0); 3901 } 3902 has_addr: 3903 if (need_mapping) { 3904 /* b_offset is handled by bpmap_qenter. */ 3905 bp->b_data = bp->b_kvabase; 3906 BUF_CHECK_MAPPED(bp); 3907 bpmap_qenter(bp); 3908 } 3909 } 3910 3911 struct buf * 3912 getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo, 3913 int flags) 3914 { 3915 struct buf *bp; 3916 int error; 3917 3918 error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp); 3919 if (error != 0) 3920 return (NULL); 3921 return (bp); 3922 } 3923 3924 /* 3925 * getblkx: 3926 * 3927 * Get a block given a specified block and offset into a file/device. 3928 * The buffers B_DONE bit will be cleared on return, making it almost 3929 * ready for an I/O initiation. B_INVAL may or may not be set on 3930 * return. The caller should clear B_INVAL prior to initiating a 3931 * READ. 3932 * 3933 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for 3934 * an existing buffer. 3935 * 3936 * For a VMIO buffer, B_CACHE is modified according to the backing VM. 3937 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set 3938 * and then cleared based on the backing VM. If the previous buffer is 3939 * non-0-sized but invalid, B_CACHE will be cleared. 3940 * 3941 * If getblk() must create a new buffer, the new buffer is returned with 3942 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which 3943 * case it is returned with B_INVAL clear and B_CACHE set based on the 3944 * backing VM. 3945 * 3946 * getblk() also forces a bwrite() for any B_DELWRI buffer whose 3947 * B_CACHE bit is clear. 3948 * 3949 * What this means, basically, is that the caller should use B_CACHE to 3950 * determine whether the buffer is fully valid or not and should clear 3951 * B_INVAL prior to issuing a read. If the caller intends to validate 3952 * the buffer by loading its data area with something, the caller needs 3953 * to clear B_INVAL. If the caller does this without issuing an I/O, 3954 * the caller should set B_CACHE ( as an optimization ), else the caller 3955 * should issue the I/O and biodone() will set B_CACHE if the I/O was 3956 * a write attempt or if it was a successful read. If the caller 3957 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR 3958 * prior to issuing the READ. biodone() will *not* clear B_INVAL. 3959 * 3960 * The blkno parameter is the logical block being requested. Normally 3961 * the mapping of logical block number to disk block address is done 3962 * by calling VOP_BMAP(). However, if the mapping is already known, the 3963 * disk block address can be passed using the dblkno parameter. If the 3964 * disk block address is not known, then the same value should be passed 3965 * for blkno and dblkno. 3966 */ 3967 int 3968 getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag, 3969 int slptimeo, int flags, struct buf **bpp) 3970 { 3971 struct buf *bp; 3972 struct bufobj *bo; 3973 daddr_t d_blkno; 3974 int bsize, error, maxsize, vmio; 3975 off_t offset; 3976 3977 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size); 3978 KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3979 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3980 if (vp->v_type != VCHR) 3981 ASSERT_VOP_LOCKED(vp, "getblk"); 3982 if (size > maxbcachebuf) 3983 panic("getblk: size(%d) > maxbcachebuf(%d)\n", size, 3984 maxbcachebuf); 3985 if (!unmapped_buf_allowed) 3986 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3987 3988 bo = &vp->v_bufobj; 3989 d_blkno = dblkno; 3990 3991 /* Attempt lockless lookup first. */ 3992 bp = gbincore_unlocked(bo, blkno); 3993 if (bp == NULL) { 3994 /* 3995 * With GB_NOCREAT we must be sure about not finding the buffer 3996 * as it may have been reassigned during unlocked lookup. 3997 */ 3998 if ((flags & GB_NOCREAT) != 0) 3999 goto loop; 4000 goto newbuf_unlocked; 4001 } 4002 4003 error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL, "getblku", 0, 4004 0); 4005 if (error != 0) 4006 goto loop; 4007 4008 /* Verify buf identify has not changed since lookup. */ 4009 if (bp->b_bufobj == bo && bp->b_lblkno == blkno) 4010 goto foundbuf_fastpath; 4011 4012 /* It changed, fallback to locked lookup. */ 4013 BUF_UNLOCK_RAW(bp); 4014 4015 loop: 4016 BO_RLOCK(bo); 4017 bp = gbincore(bo, blkno); 4018 if (bp != NULL) { 4019 int lockflags; 4020 4021 /* 4022 * Buffer is in-core. If the buffer is not busy nor managed, 4023 * it must be on a queue. 4024 */ 4025 lockflags = LK_EXCLUSIVE | LK_INTERLOCK | 4026 ((flags & GB_LOCK_NOWAIT) != 0 ? LK_NOWAIT : LK_SLEEPFAIL); 4027 #ifdef WITNESS 4028 lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0; 4029 #endif 4030 4031 error = BUF_TIMELOCK(bp, lockflags, 4032 BO_LOCKPTR(bo), "getblk", slpflag, slptimeo); 4033 4034 /* 4035 * If we slept and got the lock we have to restart in case 4036 * the buffer changed identities. 4037 */ 4038 if (error == ENOLCK) 4039 goto loop; 4040 /* We timed out or were interrupted. */ 4041 else if (error != 0) 4042 return (error); 4043 4044 foundbuf_fastpath: 4045 /* If recursed, assume caller knows the rules. */ 4046 if (BUF_LOCKRECURSED(bp)) 4047 goto end; 4048 4049 /* 4050 * The buffer is locked. B_CACHE is cleared if the buffer is 4051 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set 4052 * and for a VMIO buffer B_CACHE is adjusted according to the 4053 * backing VM cache. 4054 */ 4055 if (bp->b_flags & B_INVAL) 4056 bp->b_flags &= ~B_CACHE; 4057 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0) 4058 bp->b_flags |= B_CACHE; 4059 if (bp->b_flags & B_MANAGED) 4060 MPASS(bp->b_qindex == QUEUE_NONE); 4061 else 4062 bremfree(bp); 4063 4064 /* 4065 * check for size inconsistencies for non-VMIO case. 4066 */ 4067 if (bp->b_bcount != size) { 4068 if ((bp->b_flags & B_VMIO) == 0 || 4069 (size > bp->b_kvasize)) { 4070 if (bp->b_flags & B_DELWRI) { 4071 bp->b_flags |= B_NOCACHE; 4072 bwrite(bp); 4073 } else { 4074 if (LIST_EMPTY(&bp->b_dep)) { 4075 bp->b_flags |= B_RELBUF; 4076 brelse(bp); 4077 } else { 4078 bp->b_flags |= B_NOCACHE; 4079 bwrite(bp); 4080 } 4081 } 4082 goto loop; 4083 } 4084 } 4085 4086 /* 4087 * Handle the case of unmapped buffer which should 4088 * become mapped, or the buffer for which KVA 4089 * reservation is requested. 4090 */ 4091 bp_unmapped_get_kva(bp, blkno, size, flags); 4092 4093 /* 4094 * If the size is inconsistent in the VMIO case, we can resize 4095 * the buffer. This might lead to B_CACHE getting set or 4096 * cleared. If the size has not changed, B_CACHE remains 4097 * unchanged from its previous state. 4098 */ 4099 allocbuf(bp, size); 4100 4101 KASSERT(bp->b_offset != NOOFFSET, 4102 ("getblk: no buffer offset")); 4103 4104 /* 4105 * A buffer with B_DELWRI set and B_CACHE clear must 4106 * be committed before we can return the buffer in 4107 * order to prevent the caller from issuing a read 4108 * ( due to B_CACHE not being set ) and overwriting 4109 * it. 4110 * 4111 * Most callers, including NFS and FFS, need this to 4112 * operate properly either because they assume they 4113 * can issue a read if B_CACHE is not set, or because 4114 * ( for example ) an uncached B_DELWRI might loop due 4115 * to softupdates re-dirtying the buffer. In the latter 4116 * case, B_CACHE is set after the first write completes, 4117 * preventing further loops. 4118 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE 4119 * above while extending the buffer, we cannot allow the 4120 * buffer to remain with B_CACHE set after the write 4121 * completes or it will represent a corrupt state. To 4122 * deal with this we set B_NOCACHE to scrap the buffer 4123 * after the write. 4124 * 4125 * We might be able to do something fancy, like setting 4126 * B_CACHE in bwrite() except if B_DELWRI is already set, 4127 * so the below call doesn't set B_CACHE, but that gets real 4128 * confusing. This is much easier. 4129 */ 4130 4131 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) { 4132 bp->b_flags |= B_NOCACHE; 4133 bwrite(bp); 4134 goto loop; 4135 } 4136 bp->b_flags &= ~B_DONE; 4137 } else { 4138 /* 4139 * Buffer is not in-core, create new buffer. The buffer 4140 * returned by getnewbuf() is locked. Note that the returned 4141 * buffer is also considered valid (not marked B_INVAL). 4142 */ 4143 BO_RUNLOCK(bo); 4144 newbuf_unlocked: 4145 /* 4146 * If the user does not want us to create the buffer, bail out 4147 * here. 4148 */ 4149 if (flags & GB_NOCREAT) 4150 return (EEXIST); 4151 4152 bsize = vn_isdisk(vp) ? DEV_BSIZE : bo->bo_bsize; 4153 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 4154 offset = blkno * bsize; 4155 vmio = vp->v_object != NULL; 4156 if (vmio) { 4157 maxsize = size + (offset & PAGE_MASK); 4158 } else { 4159 maxsize = size; 4160 /* Do not allow non-VMIO notmapped buffers. */ 4161 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 4162 } 4163 maxsize = imax(maxsize, bsize); 4164 if ((flags & GB_NOSPARSE) != 0 && vmio && 4165 !vn_isdisk(vp)) { 4166 error = VOP_BMAP(vp, blkno, NULL, &d_blkno, 0, 0); 4167 KASSERT(error != EOPNOTSUPP, 4168 ("GB_NOSPARSE from fs not supporting bmap, vp %p", 4169 vp)); 4170 if (error != 0) 4171 return (error); 4172 if (d_blkno == -1) 4173 return (EJUSTRETURN); 4174 } 4175 4176 bp = getnewbuf(vp, slpflag, slptimeo, maxsize, flags); 4177 if (bp == NULL) { 4178 if (slpflag || slptimeo) 4179 return (ETIMEDOUT); 4180 /* 4181 * XXX This is here until the sleep path is diagnosed 4182 * enough to work under very low memory conditions. 4183 * 4184 * There's an issue on low memory, 4BSD+non-preempt 4185 * systems (eg MIPS routers with 32MB RAM) where buffer 4186 * exhaustion occurs without sleeping for buffer 4187 * reclaimation. This just sticks in a loop and 4188 * constantly attempts to allocate a buffer, which 4189 * hits exhaustion and tries to wakeup bufdaemon. 4190 * This never happens because we never yield. 4191 * 4192 * The real solution is to identify and fix these cases 4193 * so we aren't effectively busy-waiting in a loop 4194 * until the reclaimation path has cycles to run. 4195 */ 4196 kern_yield(PRI_USER); 4197 goto loop; 4198 } 4199 4200 /* 4201 * This code is used to make sure that a buffer is not 4202 * created while the getnewbuf routine is blocked. 4203 * This can be a problem whether the vnode is locked or not. 4204 * If the buffer is created out from under us, we have to 4205 * throw away the one we just created. 4206 * 4207 * Note: this must occur before we associate the buffer 4208 * with the vp especially considering limitations in 4209 * the splay tree implementation when dealing with duplicate 4210 * lblkno's. 4211 */ 4212 BO_LOCK(bo); 4213 if (gbincore(bo, blkno)) { 4214 BO_UNLOCK(bo); 4215 bp->b_flags |= B_INVAL; 4216 bufspace_release(bufdomain(bp), maxsize); 4217 brelse(bp); 4218 goto loop; 4219 } 4220 4221 /* 4222 * Insert the buffer into the hash, so that it can 4223 * be found by incore. 4224 */ 4225 bp->b_lblkno = blkno; 4226 bp->b_blkno = d_blkno; 4227 bp->b_offset = offset; 4228 bgetvp(vp, bp); 4229 BO_UNLOCK(bo); 4230 4231 /* 4232 * set B_VMIO bit. allocbuf() the buffer bigger. Since the 4233 * buffer size starts out as 0, B_CACHE will be set by 4234 * allocbuf() for the VMIO case prior to it testing the 4235 * backing store for validity. 4236 */ 4237 4238 if (vmio) { 4239 bp->b_flags |= B_VMIO; 4240 KASSERT(vp->v_object == bp->b_bufobj->bo_object, 4241 ("ARGH! different b_bufobj->bo_object %p %p %p\n", 4242 bp, vp->v_object, bp->b_bufobj->bo_object)); 4243 } else { 4244 bp->b_flags &= ~B_VMIO; 4245 KASSERT(bp->b_bufobj->bo_object == NULL, 4246 ("ARGH! has b_bufobj->bo_object %p %p\n", 4247 bp, bp->b_bufobj->bo_object)); 4248 BUF_CHECK_MAPPED(bp); 4249 } 4250 4251 allocbuf(bp, size); 4252 bufspace_release(bufdomain(bp), maxsize); 4253 bp->b_flags &= ~B_DONE; 4254 } 4255 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp); 4256 end: 4257 buf_track(bp, __func__); 4258 KASSERT(bp->b_bufobj == bo, 4259 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo)); 4260 *bpp = bp; 4261 return (0); 4262 } 4263 4264 /* 4265 * Get an empty, disassociated buffer of given size. The buffer is initially 4266 * set to B_INVAL. 4267 */ 4268 struct buf * 4269 geteblk(int size, int flags) 4270 { 4271 struct buf *bp; 4272 int maxsize; 4273 4274 maxsize = (size + BKVAMASK) & ~BKVAMASK; 4275 while ((bp = getnewbuf(NULL, 0, 0, maxsize, flags)) == NULL) { 4276 if ((flags & GB_NOWAIT_BD) && 4277 (curthread->td_pflags & TDP_BUFNEED) != 0) 4278 return (NULL); 4279 } 4280 allocbuf(bp, size); 4281 bufspace_release(bufdomain(bp), maxsize); 4282 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 4283 return (bp); 4284 } 4285 4286 /* 4287 * Truncate the backing store for a non-vmio buffer. 4288 */ 4289 static void 4290 vfs_nonvmio_truncate(struct buf *bp, int newbsize) 4291 { 4292 4293 if (bp->b_flags & B_MALLOC) { 4294 /* 4295 * malloced buffers are not shrunk 4296 */ 4297 if (newbsize == 0) { 4298 bufmallocadjust(bp, 0); 4299 free(bp->b_data, M_BIOBUF); 4300 bp->b_data = bp->b_kvabase; 4301 bp->b_flags &= ~B_MALLOC; 4302 } 4303 return; 4304 } 4305 vm_hold_free_pages(bp, newbsize); 4306 bufspace_adjust(bp, newbsize); 4307 } 4308 4309 /* 4310 * Extend the backing for a non-VMIO buffer. 4311 */ 4312 static void 4313 vfs_nonvmio_extend(struct buf *bp, int newbsize) 4314 { 4315 caddr_t origbuf; 4316 int origbufsize; 4317 4318 /* 4319 * We only use malloced memory on the first allocation. 4320 * and revert to page-allocated memory when the buffer 4321 * grows. 4322 * 4323 * There is a potential smp race here that could lead 4324 * to bufmallocspace slightly passing the max. It 4325 * is probably extremely rare and not worth worrying 4326 * over. 4327 */ 4328 if (bp->b_bufsize == 0 && newbsize <= PAGE_SIZE/2 && 4329 bufmallocspace < maxbufmallocspace) { 4330 bp->b_data = malloc(newbsize, M_BIOBUF, M_WAITOK); 4331 bp->b_flags |= B_MALLOC; 4332 bufmallocadjust(bp, newbsize); 4333 return; 4334 } 4335 4336 /* 4337 * If the buffer is growing on its other-than-first 4338 * allocation then we revert to the page-allocation 4339 * scheme. 4340 */ 4341 origbuf = NULL; 4342 origbufsize = 0; 4343 if (bp->b_flags & B_MALLOC) { 4344 origbuf = bp->b_data; 4345 origbufsize = bp->b_bufsize; 4346 bp->b_data = bp->b_kvabase; 4347 bufmallocadjust(bp, 0); 4348 bp->b_flags &= ~B_MALLOC; 4349 newbsize = round_page(newbsize); 4350 } 4351 vm_hold_load_pages(bp, (vm_offset_t) bp->b_data + bp->b_bufsize, 4352 (vm_offset_t) bp->b_data + newbsize); 4353 if (origbuf != NULL) { 4354 bcopy(origbuf, bp->b_data, origbufsize); 4355 free(origbuf, M_BIOBUF); 4356 } 4357 bufspace_adjust(bp, newbsize); 4358 } 4359 4360 /* 4361 * This code constitutes the buffer memory from either anonymous system 4362 * memory (in the case of non-VMIO operations) or from an associated 4363 * VM object (in the case of VMIO operations). This code is able to 4364 * resize a buffer up or down. 4365 * 4366 * Note that this code is tricky, and has many complications to resolve 4367 * deadlock or inconsistent data situations. Tread lightly!!! 4368 * There are B_CACHE and B_DELWRI interactions that must be dealt with by 4369 * the caller. Calling this code willy nilly can result in the loss of data. 4370 * 4371 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with 4372 * B_CACHE for the non-VMIO case. 4373 */ 4374 int 4375 allocbuf(struct buf *bp, int size) 4376 { 4377 int newbsize; 4378 4379 if (bp->b_bcount == size) 4380 return (1); 4381 4382 KASSERT(bp->b_kvasize == 0 || bp->b_kvasize >= size, 4383 ("allocbuf: buffer too small %p %#x %#x", 4384 bp, bp->b_kvasize, size)); 4385 4386 newbsize = roundup2(size, DEV_BSIZE); 4387 if ((bp->b_flags & B_VMIO) == 0) { 4388 if ((bp->b_flags & B_MALLOC) == 0) 4389 newbsize = round_page(newbsize); 4390 /* 4391 * Just get anonymous memory from the kernel. Don't 4392 * mess with B_CACHE. 4393 */ 4394 if (newbsize < bp->b_bufsize) 4395 vfs_nonvmio_truncate(bp, newbsize); 4396 else if (newbsize > bp->b_bufsize) 4397 vfs_nonvmio_extend(bp, newbsize); 4398 } else { 4399 int desiredpages; 4400 4401 desiredpages = size == 0 ? 0 : 4402 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 4403 4404 KASSERT((bp->b_flags & B_MALLOC) == 0, 4405 ("allocbuf: VMIO buffer can't be malloced %p", bp)); 4406 4407 /* 4408 * Set B_CACHE initially if buffer is 0 length or will become 4409 * 0-length. 4410 */ 4411 if (size == 0 || bp->b_bufsize == 0) 4412 bp->b_flags |= B_CACHE; 4413 4414 if (newbsize < bp->b_bufsize) 4415 vfs_vmio_truncate(bp, desiredpages); 4416 /* XXX This looks as if it should be newbsize > b_bufsize */ 4417 else if (size > bp->b_bcount) 4418 vfs_vmio_extend(bp, desiredpages, size); 4419 bufspace_adjust(bp, newbsize); 4420 } 4421 bp->b_bcount = size; /* requested buffer size. */ 4422 return (1); 4423 } 4424 4425 extern int inflight_transient_maps; 4426 4427 static struct bio_queue nondump_bios; 4428 4429 void 4430 biodone(struct bio *bp) 4431 { 4432 struct mtx *mtxp; 4433 void (*done)(struct bio *); 4434 vm_offset_t start, end; 4435 4436 biotrack(bp, __func__); 4437 4438 /* 4439 * Avoid completing I/O when dumping after a panic since that may 4440 * result in a deadlock in the filesystem or pager code. Note that 4441 * this doesn't affect dumps that were started manually since we aim 4442 * to keep the system usable after it has been resumed. 4443 */ 4444 if (__predict_false(dumping && SCHEDULER_STOPPED())) { 4445 TAILQ_INSERT_HEAD(&nondump_bios, bp, bio_queue); 4446 return; 4447 } 4448 if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { 4449 bp->bio_flags &= ~BIO_TRANSIENT_MAPPING; 4450 bp->bio_flags |= BIO_UNMAPPED; 4451 start = trunc_page((vm_offset_t)bp->bio_data); 4452 end = round_page((vm_offset_t)bp->bio_data + bp->bio_length); 4453 bp->bio_data = unmapped_buf; 4454 pmap_qremove(start, atop(end - start)); 4455 vmem_free(transient_arena, start, end - start); 4456 atomic_add_int(&inflight_transient_maps, -1); 4457 } 4458 done = bp->bio_done; 4459 /* 4460 * The check for done == biodone is to allow biodone to be 4461 * used as a bio_done routine. 4462 */ 4463 if (done == NULL || done == biodone) { 4464 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4465 mtx_lock(mtxp); 4466 bp->bio_flags |= BIO_DONE; 4467 wakeup(bp); 4468 mtx_unlock(mtxp); 4469 } else 4470 done(bp); 4471 } 4472 4473 /* 4474 * Wait for a BIO to finish. 4475 */ 4476 int 4477 biowait(struct bio *bp, const char *wmesg) 4478 { 4479 struct mtx *mtxp; 4480 4481 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4482 mtx_lock(mtxp); 4483 while ((bp->bio_flags & BIO_DONE) == 0) 4484 msleep(bp, mtxp, PRIBIO, wmesg, 0); 4485 mtx_unlock(mtxp); 4486 if (bp->bio_error != 0) 4487 return (bp->bio_error); 4488 if (!(bp->bio_flags & BIO_ERROR)) 4489 return (0); 4490 return (EIO); 4491 } 4492 4493 void 4494 biofinish(struct bio *bp, struct devstat *stat, int error) 4495 { 4496 4497 if (error) { 4498 bp->bio_error = error; 4499 bp->bio_flags |= BIO_ERROR; 4500 } 4501 if (stat != NULL) 4502 devstat_end_transaction_bio(stat, bp); 4503 biodone(bp); 4504 } 4505 4506 #if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING) 4507 void 4508 biotrack_buf(struct bio *bp, const char *location) 4509 { 4510 4511 buf_track(bp->bio_track_bp, location); 4512 } 4513 #endif 4514 4515 /* 4516 * bufwait: 4517 * 4518 * Wait for buffer I/O completion, returning error status. The buffer 4519 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR 4520 * error and cleared. 4521 */ 4522 int 4523 bufwait(struct buf *bp) 4524 { 4525 if (bp->b_iocmd == BIO_READ) 4526 bwait(bp, PRIBIO, "biord"); 4527 else 4528 bwait(bp, PRIBIO, "biowr"); 4529 if (bp->b_flags & B_EINTR) { 4530 bp->b_flags &= ~B_EINTR; 4531 return (EINTR); 4532 } 4533 if (bp->b_ioflags & BIO_ERROR) { 4534 return (bp->b_error ? bp->b_error : EIO); 4535 } else { 4536 return (0); 4537 } 4538 } 4539 4540 /* 4541 * bufdone: 4542 * 4543 * Finish I/O on a buffer, optionally calling a completion function. 4544 * This is usually called from an interrupt so process blocking is 4545 * not allowed. 4546 * 4547 * biodone is also responsible for setting B_CACHE in a B_VMIO bp. 4548 * In a non-VMIO bp, B_CACHE will be set on the next getblk() 4549 * assuming B_INVAL is clear. 4550 * 4551 * For the VMIO case, we set B_CACHE if the op was a read and no 4552 * read error occurred, or if the op was a write. B_CACHE is never 4553 * set if the buffer is invalid or otherwise uncacheable. 4554 * 4555 * bufdone does not mess with B_INVAL, allowing the I/O routine or the 4556 * initiator to leave B_INVAL set to brelse the buffer out of existence 4557 * in the biodone routine. 4558 */ 4559 void 4560 bufdone(struct buf *bp) 4561 { 4562 struct bufobj *dropobj; 4563 void (*biodone)(struct buf *); 4564 4565 buf_track(bp, __func__); 4566 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 4567 dropobj = NULL; 4568 4569 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp)); 4570 4571 runningbufwakeup(bp); 4572 if (bp->b_iocmd == BIO_WRITE) 4573 dropobj = bp->b_bufobj; 4574 /* call optional completion function if requested */ 4575 if (bp->b_iodone != NULL) { 4576 biodone = bp->b_iodone; 4577 bp->b_iodone = NULL; 4578 (*biodone) (bp); 4579 if (dropobj) 4580 bufobj_wdrop(dropobj); 4581 return; 4582 } 4583 if (bp->b_flags & B_VMIO) { 4584 /* 4585 * Set B_CACHE if the op was a normal read and no error 4586 * occurred. B_CACHE is set for writes in the b*write() 4587 * routines. 4588 */ 4589 if (bp->b_iocmd == BIO_READ && 4590 !(bp->b_flags & (B_INVAL|B_NOCACHE)) && 4591 !(bp->b_ioflags & BIO_ERROR)) 4592 bp->b_flags |= B_CACHE; 4593 vfs_vmio_iodone(bp); 4594 } 4595 if (!LIST_EMPTY(&bp->b_dep)) 4596 buf_complete(bp); 4597 if ((bp->b_flags & B_CKHASH) != 0) { 4598 KASSERT(bp->b_iocmd == BIO_READ, 4599 ("bufdone: b_iocmd %d not BIO_READ", bp->b_iocmd)); 4600 KASSERT(buf_mapped(bp), ("bufdone: bp %p not mapped", bp)); 4601 (*bp->b_ckhashcalc)(bp); 4602 } 4603 /* 4604 * For asynchronous completions, release the buffer now. The brelse 4605 * will do a wakeup there if necessary - so no need to do a wakeup 4606 * here in the async case. The sync case always needs to do a wakeup. 4607 */ 4608 if (bp->b_flags & B_ASYNC) { 4609 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || 4610 (bp->b_ioflags & BIO_ERROR)) 4611 brelse(bp); 4612 else 4613 bqrelse(bp); 4614 } else 4615 bdone(bp); 4616 if (dropobj) 4617 bufobj_wdrop(dropobj); 4618 } 4619 4620 /* 4621 * This routine is called in lieu of iodone in the case of 4622 * incomplete I/O. This keeps the busy status for pages 4623 * consistent. 4624 */ 4625 void 4626 vfs_unbusy_pages(struct buf *bp) 4627 { 4628 int i; 4629 vm_object_t obj; 4630 vm_page_t m; 4631 4632 runningbufwakeup(bp); 4633 if (!(bp->b_flags & B_VMIO)) 4634 return; 4635 4636 obj = bp->b_bufobj->bo_object; 4637 for (i = 0; i < bp->b_npages; i++) { 4638 m = bp->b_pages[i]; 4639 if (m == bogus_page) { 4640 m = vm_page_relookup(obj, OFF_TO_IDX(bp->b_offset) + i); 4641 if (!m) 4642 panic("vfs_unbusy_pages: page missing\n"); 4643 bp->b_pages[i] = m; 4644 if (buf_mapped(bp)) { 4645 BUF_CHECK_MAPPED(bp); 4646 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4647 bp->b_pages, bp->b_npages); 4648 } else 4649 BUF_CHECK_UNMAPPED(bp); 4650 } 4651 vm_page_sunbusy(m); 4652 } 4653 vm_object_pip_wakeupn(obj, bp->b_npages); 4654 } 4655 4656 /* 4657 * vfs_page_set_valid: 4658 * 4659 * Set the valid bits in a page based on the supplied offset. The 4660 * range is restricted to the buffer's size. 4661 * 4662 * This routine is typically called after a read completes. 4663 */ 4664 static void 4665 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4666 { 4667 vm_ooffset_t eoff; 4668 4669 /* 4670 * Compute the end offset, eoff, such that [off, eoff) does not span a 4671 * page boundary and eoff is not greater than the end of the buffer. 4672 * The end of the buffer, in this case, is our file EOF, not the 4673 * allocation size of the buffer. 4674 */ 4675 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK; 4676 if (eoff > bp->b_offset + bp->b_bcount) 4677 eoff = bp->b_offset + bp->b_bcount; 4678 4679 /* 4680 * Set valid range. This is typically the entire buffer and thus the 4681 * entire page. 4682 */ 4683 if (eoff > off) 4684 vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off); 4685 } 4686 4687 /* 4688 * vfs_page_set_validclean: 4689 * 4690 * Set the valid bits and clear the dirty bits in a page based on the 4691 * supplied offset. The range is restricted to the buffer's size. 4692 */ 4693 static void 4694 vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4695 { 4696 vm_ooffset_t soff, eoff; 4697 4698 /* 4699 * Start and end offsets in buffer. eoff - soff may not cross a 4700 * page boundary or cross the end of the buffer. The end of the 4701 * buffer, in this case, is our file EOF, not the allocation size 4702 * of the buffer. 4703 */ 4704 soff = off; 4705 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4706 if (eoff > bp->b_offset + bp->b_bcount) 4707 eoff = bp->b_offset + bp->b_bcount; 4708 4709 /* 4710 * Set valid range. This is typically the entire buffer and thus the 4711 * entire page. 4712 */ 4713 if (eoff > soff) { 4714 vm_page_set_validclean( 4715 m, 4716 (vm_offset_t) (soff & PAGE_MASK), 4717 (vm_offset_t) (eoff - soff) 4718 ); 4719 } 4720 } 4721 4722 /* 4723 * Acquire a shared busy on all pages in the buf. 4724 */ 4725 void 4726 vfs_busy_pages_acquire(struct buf *bp) 4727 { 4728 int i; 4729 4730 for (i = 0; i < bp->b_npages; i++) 4731 vm_page_busy_acquire(bp->b_pages[i], VM_ALLOC_SBUSY); 4732 } 4733 4734 void 4735 vfs_busy_pages_release(struct buf *bp) 4736 { 4737 int i; 4738 4739 for (i = 0; i < bp->b_npages; i++) 4740 vm_page_sunbusy(bp->b_pages[i]); 4741 } 4742 4743 /* 4744 * This routine is called before a device strategy routine. 4745 * It is used to tell the VM system that paging I/O is in 4746 * progress, and treat the pages associated with the buffer 4747 * almost as being exclusive busy. Also the object paging_in_progress 4748 * flag is handled to make sure that the object doesn't become 4749 * inconsistent. 4750 * 4751 * Since I/O has not been initiated yet, certain buffer flags 4752 * such as BIO_ERROR or B_INVAL may be in an inconsistent state 4753 * and should be ignored. 4754 */ 4755 void 4756 vfs_busy_pages(struct buf *bp, int clear_modify) 4757 { 4758 vm_object_t obj; 4759 vm_ooffset_t foff; 4760 vm_page_t m; 4761 int i; 4762 bool bogus; 4763 4764 if (!(bp->b_flags & B_VMIO)) 4765 return; 4766 4767 obj = bp->b_bufobj->bo_object; 4768 foff = bp->b_offset; 4769 KASSERT(bp->b_offset != NOOFFSET, 4770 ("vfs_busy_pages: no buffer offset")); 4771 if ((bp->b_flags & B_CLUSTER) == 0) { 4772 vm_object_pip_add(obj, bp->b_npages); 4773 vfs_busy_pages_acquire(bp); 4774 } 4775 if (bp->b_bufsize != 0) 4776 vfs_setdirty_range(bp); 4777 bogus = false; 4778 for (i = 0; i < bp->b_npages; i++) { 4779 m = bp->b_pages[i]; 4780 vm_page_assert_sbusied(m); 4781 4782 /* 4783 * When readying a buffer for a read ( i.e 4784 * clear_modify == 0 ), it is important to do 4785 * bogus_page replacement for valid pages in 4786 * partially instantiated buffers. Partially 4787 * instantiated buffers can, in turn, occur when 4788 * reconstituting a buffer from its VM backing store 4789 * base. We only have to do this if B_CACHE is 4790 * clear ( which causes the I/O to occur in the 4791 * first place ). The replacement prevents the read 4792 * I/O from overwriting potentially dirty VM-backed 4793 * pages. XXX bogus page replacement is, uh, bogus. 4794 * It may not work properly with small-block devices. 4795 * We need to find a better way. 4796 */ 4797 if (clear_modify) { 4798 pmap_remove_write(m); 4799 vfs_page_set_validclean(bp, foff, m); 4800 } else if (vm_page_all_valid(m) && 4801 (bp->b_flags & B_CACHE) == 0) { 4802 bp->b_pages[i] = bogus_page; 4803 bogus = true; 4804 } 4805 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4806 } 4807 if (bogus && buf_mapped(bp)) { 4808 BUF_CHECK_MAPPED(bp); 4809 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4810 bp->b_pages, bp->b_npages); 4811 } 4812 } 4813 4814 /* 4815 * vfs_bio_set_valid: 4816 * 4817 * Set the range within the buffer to valid. The range is 4818 * relative to the beginning of the buffer, b_offset. Note that 4819 * b_offset itself may be offset from the beginning of the first 4820 * page. 4821 */ 4822 void 4823 vfs_bio_set_valid(struct buf *bp, int base, int size) 4824 { 4825 int i, n; 4826 vm_page_t m; 4827 4828 if (!(bp->b_flags & B_VMIO)) 4829 return; 4830 4831 /* 4832 * Fixup base to be relative to beginning of first page. 4833 * Set initial n to be the maximum number of bytes in the 4834 * first page that can be validated. 4835 */ 4836 base += (bp->b_offset & PAGE_MASK); 4837 n = PAGE_SIZE - (base & PAGE_MASK); 4838 4839 /* 4840 * Busy may not be strictly necessary here because the pages are 4841 * unlikely to be fully valid and the vnode lock will synchronize 4842 * their access via getpages. It is grabbed for consistency with 4843 * other page validation. 4844 */ 4845 vfs_busy_pages_acquire(bp); 4846 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4847 m = bp->b_pages[i]; 4848 if (n > size) 4849 n = size; 4850 vm_page_set_valid_range(m, base & PAGE_MASK, n); 4851 base += n; 4852 size -= n; 4853 n = PAGE_SIZE; 4854 } 4855 vfs_busy_pages_release(bp); 4856 } 4857 4858 /* 4859 * vfs_bio_clrbuf: 4860 * 4861 * If the specified buffer is a non-VMIO buffer, clear the entire 4862 * buffer. If the specified buffer is a VMIO buffer, clear and 4863 * validate only the previously invalid portions of the buffer. 4864 * This routine essentially fakes an I/O, so we need to clear 4865 * BIO_ERROR and B_INVAL. 4866 * 4867 * Note that while we only theoretically need to clear through b_bcount, 4868 * we go ahead and clear through b_bufsize. 4869 */ 4870 void 4871 vfs_bio_clrbuf(struct buf *bp) 4872 { 4873 int i, j, sa, ea, slide, zbits; 4874 vm_page_bits_t mask; 4875 4876 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) { 4877 clrbuf(bp); 4878 return; 4879 } 4880 bp->b_flags &= ~B_INVAL; 4881 bp->b_ioflags &= ~BIO_ERROR; 4882 vfs_busy_pages_acquire(bp); 4883 sa = bp->b_offset & PAGE_MASK; 4884 slide = 0; 4885 for (i = 0; i < bp->b_npages; i++, sa = 0) { 4886 slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize); 4887 ea = slide & PAGE_MASK; 4888 if (ea == 0) 4889 ea = PAGE_SIZE; 4890 if (bp->b_pages[i] == bogus_page) 4891 continue; 4892 j = sa / DEV_BSIZE; 4893 zbits = (sizeof(vm_page_bits_t) * NBBY) - 4894 (ea - sa) / DEV_BSIZE; 4895 mask = (VM_PAGE_BITS_ALL >> zbits) << j; 4896 if ((bp->b_pages[i]->valid & mask) == mask) 4897 continue; 4898 if ((bp->b_pages[i]->valid & mask) == 0) 4899 pmap_zero_page_area(bp->b_pages[i], sa, ea - sa); 4900 else { 4901 for (; sa < ea; sa += DEV_BSIZE, j++) { 4902 if ((bp->b_pages[i]->valid & (1 << j)) == 0) { 4903 pmap_zero_page_area(bp->b_pages[i], 4904 sa, DEV_BSIZE); 4905 } 4906 } 4907 } 4908 vm_page_set_valid_range(bp->b_pages[i], j * DEV_BSIZE, 4909 roundup2(ea - sa, DEV_BSIZE)); 4910 } 4911 vfs_busy_pages_release(bp); 4912 bp->b_resid = 0; 4913 } 4914 4915 void 4916 vfs_bio_bzero_buf(struct buf *bp, int base, int size) 4917 { 4918 vm_page_t m; 4919 int i, n; 4920 4921 if (buf_mapped(bp)) { 4922 BUF_CHECK_MAPPED(bp); 4923 bzero(bp->b_data + base, size); 4924 } else { 4925 BUF_CHECK_UNMAPPED(bp); 4926 n = PAGE_SIZE - (base & PAGE_MASK); 4927 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4928 m = bp->b_pages[i]; 4929 if (n > size) 4930 n = size; 4931 pmap_zero_page_area(m, base & PAGE_MASK, n); 4932 base += n; 4933 size -= n; 4934 n = PAGE_SIZE; 4935 } 4936 } 4937 } 4938 4939 /* 4940 * Update buffer flags based on I/O request parameters, optionally releasing the 4941 * buffer. If it's VMIO or direct I/O, the buffer pages are released to the VM, 4942 * where they may be placed on a page queue (VMIO) or freed immediately (direct 4943 * I/O). Otherwise the buffer is released to the cache. 4944 */ 4945 static void 4946 b_io_dismiss(struct buf *bp, int ioflag, bool release) 4947 { 4948 4949 KASSERT((ioflag & IO_NOREUSE) == 0 || (ioflag & IO_VMIO) != 0, 4950 ("buf %p non-VMIO noreuse", bp)); 4951 4952 if ((ioflag & IO_DIRECT) != 0) 4953 bp->b_flags |= B_DIRECT; 4954 if ((ioflag & IO_EXT) != 0) 4955 bp->b_xflags |= BX_ALTDATA; 4956 if ((ioflag & (IO_VMIO | IO_DIRECT)) != 0 && LIST_EMPTY(&bp->b_dep)) { 4957 bp->b_flags |= B_RELBUF; 4958 if ((ioflag & IO_NOREUSE) != 0) 4959 bp->b_flags |= B_NOREUSE; 4960 if (release) 4961 brelse(bp); 4962 } else if (release) 4963 bqrelse(bp); 4964 } 4965 4966 void 4967 vfs_bio_brelse(struct buf *bp, int ioflag) 4968 { 4969 4970 b_io_dismiss(bp, ioflag, true); 4971 } 4972 4973 void 4974 vfs_bio_set_flags(struct buf *bp, int ioflag) 4975 { 4976 4977 b_io_dismiss(bp, ioflag, false); 4978 } 4979 4980 /* 4981 * vm_hold_load_pages and vm_hold_free_pages get pages into 4982 * a buffers address space. The pages are anonymous and are 4983 * not associated with a file object. 4984 */ 4985 static void 4986 vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to) 4987 { 4988 vm_offset_t pg; 4989 vm_page_t p; 4990 int index; 4991 4992 BUF_CHECK_MAPPED(bp); 4993 4994 to = round_page(to); 4995 from = round_page(from); 4996 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 4997 MPASS((bp->b_flags & B_MAXPHYS) == 0); 4998 KASSERT(to - from <= maxbcachebuf, 4999 ("vm_hold_load_pages too large %p %#jx %#jx %u", 5000 bp, (uintmax_t)from, (uintmax_t)to, maxbcachebuf)); 5001 5002 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 5003 /* 5004 * note: must allocate system pages since blocking here 5005 * could interfere with paging I/O, no matter which 5006 * process we are. 5007 */ 5008 p = vm_page_alloc_noobj(VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | 5009 VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT) | VM_ALLOC_WAITOK); 5010 pmap_qenter(pg, &p, 1); 5011 bp->b_pages[index] = p; 5012 } 5013 bp->b_npages = index; 5014 } 5015 5016 /* Return pages associated with this buf to the vm system */ 5017 static void 5018 vm_hold_free_pages(struct buf *bp, int newbsize) 5019 { 5020 vm_offset_t from; 5021 vm_page_t p; 5022 int index, newnpages; 5023 5024 BUF_CHECK_MAPPED(bp); 5025 5026 from = round_page((vm_offset_t)bp->b_data + newbsize); 5027 newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 5028 if (bp->b_npages > newnpages) 5029 pmap_qremove(from, bp->b_npages - newnpages); 5030 for (index = newnpages; index < bp->b_npages; index++) { 5031 p = bp->b_pages[index]; 5032 bp->b_pages[index] = NULL; 5033 vm_page_unwire_noq(p); 5034 vm_page_free(p); 5035 } 5036 bp->b_npages = newnpages; 5037 } 5038 5039 /* 5040 * Map an IO request into kernel virtual address space. 5041 * 5042 * All requests are (re)mapped into kernel VA space. 5043 * Notice that we use b_bufsize for the size of the buffer 5044 * to be mapped. b_bcount might be modified by the driver. 5045 * 5046 * Note that even if the caller determines that the address space should 5047 * be valid, a race or a smaller-file mapped into a larger space may 5048 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST 5049 * check the return value. 5050 * 5051 * This function only works with pager buffers. 5052 */ 5053 int 5054 vmapbuf(struct buf *bp, void *uaddr, size_t len, int mapbuf) 5055 { 5056 vm_prot_t prot; 5057 int pidx; 5058 5059 MPASS((bp->b_flags & B_MAXPHYS) != 0); 5060 prot = VM_PROT_READ; 5061 if (bp->b_iocmd == BIO_READ) 5062 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 5063 pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 5064 (vm_offset_t)uaddr, len, prot, bp->b_pages, PBUF_PAGES); 5065 if (pidx < 0) 5066 return (-1); 5067 bp->b_bufsize = len; 5068 bp->b_npages = pidx; 5069 bp->b_offset = ((vm_offset_t)uaddr) & PAGE_MASK; 5070 if (mapbuf || !unmapped_buf_allowed) { 5071 pmap_qenter((vm_offset_t)bp->b_kvabase, bp->b_pages, pidx); 5072 bp->b_data = bp->b_kvabase + bp->b_offset; 5073 } else 5074 bp->b_data = unmapped_buf; 5075 return (0); 5076 } 5077 5078 /* 5079 * Free the io map PTEs associated with this IO operation. 5080 * We also invalidate the TLB entries and restore the original b_addr. 5081 * 5082 * This function only works with pager buffers. 5083 */ 5084 void 5085 vunmapbuf(struct buf *bp) 5086 { 5087 int npages; 5088 5089 npages = bp->b_npages; 5090 if (buf_mapped(bp)) 5091 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages); 5092 vm_page_unhold_pages(bp->b_pages, npages); 5093 5094 bp->b_data = unmapped_buf; 5095 } 5096 5097 void 5098 bdone(struct buf *bp) 5099 { 5100 struct mtx *mtxp; 5101 5102 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5103 mtx_lock(mtxp); 5104 bp->b_flags |= B_DONE; 5105 wakeup(bp); 5106 mtx_unlock(mtxp); 5107 } 5108 5109 void 5110 bwait(struct buf *bp, u_char pri, const char *wchan) 5111 { 5112 struct mtx *mtxp; 5113 5114 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5115 mtx_lock(mtxp); 5116 while ((bp->b_flags & B_DONE) == 0) 5117 msleep(bp, mtxp, pri, wchan, 0); 5118 mtx_unlock(mtxp); 5119 } 5120 5121 int 5122 bufsync(struct bufobj *bo, int waitfor) 5123 { 5124 5125 return (VOP_FSYNC(bo2vnode(bo), waitfor, curthread)); 5126 } 5127 5128 void 5129 bufstrategy(struct bufobj *bo, struct buf *bp) 5130 { 5131 int i __unused; 5132 struct vnode *vp; 5133 5134 vp = bp->b_vp; 5135 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy")); 5136 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 5137 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp)); 5138 i = VOP_STRATEGY(vp, bp); 5139 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp)); 5140 } 5141 5142 /* 5143 * Initialize a struct bufobj before use. Memory is assumed zero filled. 5144 */ 5145 void 5146 bufobj_init(struct bufobj *bo, void *private) 5147 { 5148 static volatile int bufobj_cleanq; 5149 5150 bo->bo_domain = 5151 atomic_fetchadd_int(&bufobj_cleanq, 1) % buf_domains; 5152 rw_init(BO_LOCKPTR(bo), "bufobj interlock"); 5153 bo->bo_private = private; 5154 TAILQ_INIT(&bo->bo_clean.bv_hd); 5155 TAILQ_INIT(&bo->bo_dirty.bv_hd); 5156 } 5157 5158 void 5159 bufobj_wrefl(struct bufobj *bo) 5160 { 5161 5162 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5163 ASSERT_BO_WLOCKED(bo); 5164 bo->bo_numoutput++; 5165 } 5166 5167 void 5168 bufobj_wref(struct bufobj *bo) 5169 { 5170 5171 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5172 BO_LOCK(bo); 5173 bo->bo_numoutput++; 5174 BO_UNLOCK(bo); 5175 } 5176 5177 void 5178 bufobj_wdrop(struct bufobj *bo) 5179 { 5180 5181 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop")); 5182 BO_LOCK(bo); 5183 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count")); 5184 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) { 5185 bo->bo_flag &= ~BO_WWAIT; 5186 wakeup(&bo->bo_numoutput); 5187 } 5188 BO_UNLOCK(bo); 5189 } 5190 5191 int 5192 bufobj_wwait(struct bufobj *bo, int slpflag, int timeo) 5193 { 5194 int error; 5195 5196 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait")); 5197 ASSERT_BO_WLOCKED(bo); 5198 error = 0; 5199 while (bo->bo_numoutput) { 5200 bo->bo_flag |= BO_WWAIT; 5201 error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo), 5202 slpflag | (PRIBIO + 1), "bo_wwait", timeo); 5203 if (error) 5204 break; 5205 } 5206 return (error); 5207 } 5208 5209 /* 5210 * Set bio_data or bio_ma for struct bio from the struct buf. 5211 */ 5212 void 5213 bdata2bio(struct buf *bp, struct bio *bip) 5214 { 5215 5216 if (!buf_mapped(bp)) { 5217 KASSERT(unmapped_buf_allowed, ("unmapped")); 5218 bip->bio_ma = bp->b_pages; 5219 bip->bio_ma_n = bp->b_npages; 5220 bip->bio_data = unmapped_buf; 5221 bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK; 5222 bip->bio_flags |= BIO_UNMAPPED; 5223 KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) / 5224 PAGE_SIZE == bp->b_npages, 5225 ("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset, 5226 (long long)bip->bio_length, bip->bio_ma_n)); 5227 } else { 5228 bip->bio_data = bp->b_data; 5229 bip->bio_ma = NULL; 5230 } 5231 } 5232 5233 static int buf_pager_relbuf; 5234 SYSCTL_INT(_vfs, OID_AUTO, buf_pager_relbuf, CTLFLAG_RWTUN, 5235 &buf_pager_relbuf, 0, 5236 "Make buffer pager release buffers after reading"); 5237 5238 /* 5239 * The buffer pager. It uses buffer reads to validate pages. 5240 * 5241 * In contrast to the generic local pager from vm/vnode_pager.c, this 5242 * pager correctly and easily handles volumes where the underlying 5243 * device block size is greater than the machine page size. The 5244 * buffer cache transparently extends the requested page run to be 5245 * aligned at the block boundary, and does the necessary bogus page 5246 * replacements in the addends to avoid obliterating already valid 5247 * pages. 5248 * 5249 * The only non-trivial issue is that the exclusive busy state for 5250 * pages, which is assumed by the vm_pager_getpages() interface, is 5251 * incompatible with the VMIO buffer cache's desire to share-busy the 5252 * pages. This function performs a trivial downgrade of the pages' 5253 * state before reading buffers, and a less trivial upgrade from the 5254 * shared-busy to excl-busy state after the read. 5255 */ 5256 int 5257 vfs_bio_getpages(struct vnode *vp, vm_page_t *ma, int count, 5258 int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno, 5259 vbg_get_blksize_t get_blksize) 5260 { 5261 vm_page_t m; 5262 vm_object_t object; 5263 struct buf *bp; 5264 struct mount *mp; 5265 daddr_t lbn, lbnp; 5266 vm_ooffset_t la, lb, poff, poffe; 5267 long bo_bs, bsize; 5268 int br_flags, error, i, pgsin, pgsin_a, pgsin_b; 5269 bool redo, lpart; 5270 5271 object = vp->v_object; 5272 mp = vp->v_mount; 5273 error = 0; 5274 la = IDX_TO_OFF(ma[count - 1]->pindex); 5275 if (la >= object->un_pager.vnp.vnp_size) 5276 return (VM_PAGER_BAD); 5277 5278 /* 5279 * Change the meaning of la from where the last requested page starts 5280 * to where it ends, because that's the end of the requested region 5281 * and the start of the potential read-ahead region. 5282 */ 5283 la += PAGE_SIZE; 5284 lpart = la > object->un_pager.vnp.vnp_size; 5285 error = get_blksize(vp, get_lblkno(vp, IDX_TO_OFF(ma[0]->pindex)), 5286 &bo_bs); 5287 if (error != 0) 5288 return (VM_PAGER_ERROR); 5289 5290 /* 5291 * Calculate read-ahead, behind and total pages. 5292 */ 5293 pgsin = count; 5294 lb = IDX_TO_OFF(ma[0]->pindex); 5295 pgsin_b = OFF_TO_IDX(lb - rounddown2(lb, bo_bs)); 5296 pgsin += pgsin_b; 5297 if (rbehind != NULL) 5298 *rbehind = pgsin_b; 5299 pgsin_a = OFF_TO_IDX(roundup2(la, bo_bs) - la); 5300 if (la + IDX_TO_OFF(pgsin_a) >= object->un_pager.vnp.vnp_size) 5301 pgsin_a = OFF_TO_IDX(roundup2(object->un_pager.vnp.vnp_size, 5302 PAGE_SIZE) - la); 5303 pgsin += pgsin_a; 5304 if (rahead != NULL) 5305 *rahead = pgsin_a; 5306 VM_CNT_INC(v_vnodein); 5307 VM_CNT_ADD(v_vnodepgsin, pgsin); 5308 5309 br_flags = (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) 5310 != 0) ? GB_UNMAPPED : 0; 5311 again: 5312 for (i = 0; i < count; i++) { 5313 if (ma[i] != bogus_page) 5314 vm_page_busy_downgrade(ma[i]); 5315 } 5316 5317 lbnp = -1; 5318 for (i = 0; i < count; i++) { 5319 m = ma[i]; 5320 if (m == bogus_page) 5321 continue; 5322 5323 /* 5324 * Pages are shared busy and the object lock is not 5325 * owned, which together allow for the pages' 5326 * invalidation. The racy test for validity avoids 5327 * useless creation of the buffer for the most typical 5328 * case when invalidation is not used in redo or for 5329 * parallel read. The shared->excl upgrade loop at 5330 * the end of the function catches the race in a 5331 * reliable way (protected by the object lock). 5332 */ 5333 if (vm_page_all_valid(m)) 5334 continue; 5335 5336 poff = IDX_TO_OFF(m->pindex); 5337 poffe = MIN(poff + PAGE_SIZE, object->un_pager.vnp.vnp_size); 5338 for (; poff < poffe; poff += bsize) { 5339 lbn = get_lblkno(vp, poff); 5340 if (lbn == lbnp) 5341 goto next_page; 5342 lbnp = lbn; 5343 5344 error = get_blksize(vp, lbn, &bsize); 5345 if (error == 0) 5346 error = bread_gb(vp, lbn, bsize, 5347 curthread->td_ucred, br_flags, &bp); 5348 if (error != 0) 5349 goto end_pages; 5350 if (bp->b_rcred == curthread->td_ucred) { 5351 crfree(bp->b_rcred); 5352 bp->b_rcred = NOCRED; 5353 } 5354 if (LIST_EMPTY(&bp->b_dep)) { 5355 /* 5356 * Invalidation clears m->valid, but 5357 * may leave B_CACHE flag if the 5358 * buffer existed at the invalidation 5359 * time. In this case, recycle the 5360 * buffer to do real read on next 5361 * bread() after redo. 5362 * 5363 * Otherwise B_RELBUF is not strictly 5364 * necessary, enable to reduce buf 5365 * cache pressure. 5366 */ 5367 if (buf_pager_relbuf || 5368 !vm_page_all_valid(m)) 5369 bp->b_flags |= B_RELBUF; 5370 5371 bp->b_flags &= ~B_NOCACHE; 5372 brelse(bp); 5373 } else { 5374 bqrelse(bp); 5375 } 5376 } 5377 KASSERT(1 /* racy, enable for debugging */ || 5378 vm_page_all_valid(m) || i == count - 1, 5379 ("buf %d %p invalid", i, m)); 5380 if (i == count - 1 && lpart) { 5381 if (!vm_page_none_valid(m) && 5382 !vm_page_all_valid(m)) 5383 vm_page_zero_invalid(m, TRUE); 5384 } 5385 next_page:; 5386 } 5387 end_pages: 5388 5389 redo = false; 5390 for (i = 0; i < count; i++) { 5391 if (ma[i] == bogus_page) 5392 continue; 5393 if (vm_page_busy_tryupgrade(ma[i]) == 0) { 5394 vm_page_sunbusy(ma[i]); 5395 ma[i] = vm_page_grab_unlocked(object, ma[i]->pindex, 5396 VM_ALLOC_NORMAL); 5397 } 5398 5399 /* 5400 * Since the pages were only sbusy while neither the 5401 * buffer nor the object lock was held by us, or 5402 * reallocated while vm_page_grab() slept for busy 5403 * relinguish, they could have been invalidated. 5404 * Recheck the valid bits and re-read as needed. 5405 * 5406 * Note that the last page is made fully valid in the 5407 * read loop, and partial validity for the page at 5408 * index count - 1 could mean that the page was 5409 * invalidated or removed, so we must restart for 5410 * safety as well. 5411 */ 5412 if (!vm_page_all_valid(ma[i])) 5413 redo = true; 5414 } 5415 if (redo && error == 0) 5416 goto again; 5417 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 5418 } 5419 5420 #include "opt_ddb.h" 5421 #ifdef DDB 5422 #include <ddb/ddb.h> 5423 5424 /* DDB command to show buffer data */ 5425 DB_SHOW_COMMAND(buffer, db_show_buffer) 5426 { 5427 /* get args */ 5428 struct buf *bp = (struct buf *)addr; 5429 #ifdef FULL_BUF_TRACKING 5430 uint32_t i, j; 5431 #endif 5432 5433 if (!have_addr) { 5434 db_printf("usage: show buffer <addr>\n"); 5435 return; 5436 } 5437 5438 db_printf("buf at %p\n", bp); 5439 db_printf("b_flags = 0x%b, b_xflags=0x%b\n", 5440 (u_int)bp->b_flags, PRINT_BUF_FLAGS, 5441 (u_int)bp->b_xflags, PRINT_BUF_XFLAGS); 5442 db_printf("b_vflags=0x%b b_ioflags0x%b\n", 5443 (u_int)bp->b_vflags, PRINT_BUF_VFLAGS, 5444 (u_int)bp->b_ioflags, PRINT_BIO_FLAGS); 5445 db_printf( 5446 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n" 5447 "b_bufobj = (%p), b_data = %p\n, b_blkno = %jd, b_lblkno = %jd, " 5448 "b_vp = %p, b_dep = %p\n", 5449 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 5450 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno, 5451 (intmax_t)bp->b_lblkno, bp->b_vp, bp->b_dep.lh_first); 5452 db_printf("b_kvabase = %p, b_kvasize = %d\n", 5453 bp->b_kvabase, bp->b_kvasize); 5454 if (bp->b_npages) { 5455 int i; 5456 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 5457 for (i = 0; i < bp->b_npages; i++) { 5458 vm_page_t m; 5459 m = bp->b_pages[i]; 5460 if (m != NULL) 5461 db_printf("(%p, 0x%lx, 0x%lx)", m->object, 5462 (u_long)m->pindex, 5463 (u_long)VM_PAGE_TO_PHYS(m)); 5464 else 5465 db_printf("( ??? )"); 5466 if ((i + 1) < bp->b_npages) 5467 db_printf(","); 5468 } 5469 db_printf("\n"); 5470 } 5471 BUF_LOCKPRINTINFO(bp); 5472 #if defined(FULL_BUF_TRACKING) 5473 db_printf("b_io_tracking: b_io_tcnt = %u\n", bp->b_io_tcnt); 5474 5475 i = bp->b_io_tcnt % BUF_TRACKING_SIZE; 5476 for (j = 1; j <= BUF_TRACKING_SIZE; j++) { 5477 if (bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)] == NULL) 5478 continue; 5479 db_printf(" %2u: %s\n", j, 5480 bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)]); 5481 } 5482 #elif defined(BUF_TRACKING) 5483 db_printf("b_io_tracking: %s\n", bp->b_io_tracking); 5484 #endif 5485 db_printf(" "); 5486 } 5487 5488 DB_SHOW_COMMAND_FLAGS(bufqueues, bufqueues, DB_CMD_MEMSAFE) 5489 { 5490 struct bufdomain *bd; 5491 struct buf *bp; 5492 long total; 5493 int i, j, cnt; 5494 5495 db_printf("bqempty: %d\n", bqempty.bq_len); 5496 5497 for (i = 0; i < buf_domains; i++) { 5498 bd = &bdomain[i]; 5499 db_printf("Buf domain %d\n", i); 5500 db_printf("\tfreebufs\t%d\n", bd->bd_freebuffers); 5501 db_printf("\tlofreebufs\t%d\n", bd->bd_lofreebuffers); 5502 db_printf("\thifreebufs\t%d\n", bd->bd_hifreebuffers); 5503 db_printf("\n"); 5504 db_printf("\tbufspace\t%ld\n", bd->bd_bufspace); 5505 db_printf("\tmaxbufspace\t%ld\n", bd->bd_maxbufspace); 5506 db_printf("\thibufspace\t%ld\n", bd->bd_hibufspace); 5507 db_printf("\tlobufspace\t%ld\n", bd->bd_lobufspace); 5508 db_printf("\tbufspacethresh\t%ld\n", bd->bd_bufspacethresh); 5509 db_printf("\n"); 5510 db_printf("\tnumdirtybuffers\t%d\n", bd->bd_numdirtybuffers); 5511 db_printf("\tlodirtybuffers\t%d\n", bd->bd_lodirtybuffers); 5512 db_printf("\thidirtybuffers\t%d\n", bd->bd_hidirtybuffers); 5513 db_printf("\tdirtybufthresh\t%d\n", bd->bd_dirtybufthresh); 5514 db_printf("\n"); 5515 total = 0; 5516 TAILQ_FOREACH(bp, &bd->bd_cleanq->bq_queue, b_freelist) 5517 total += bp->b_bufsize; 5518 db_printf("\tcleanq count\t%d (%ld)\n", 5519 bd->bd_cleanq->bq_len, total); 5520 total = 0; 5521 TAILQ_FOREACH(bp, &bd->bd_dirtyq.bq_queue, b_freelist) 5522 total += bp->b_bufsize; 5523 db_printf("\tdirtyq count\t%d (%ld)\n", 5524 bd->bd_dirtyq.bq_len, total); 5525 db_printf("\twakeup\t\t%d\n", bd->bd_wanted); 5526 db_printf("\tlim\t\t%d\n", bd->bd_lim); 5527 db_printf("\tCPU "); 5528 for (j = 0; j <= mp_maxid; j++) 5529 db_printf("%d, ", bd->bd_subq[j].bq_len); 5530 db_printf("\n"); 5531 cnt = 0; 5532 total = 0; 5533 for (j = 0; j < nbuf; j++) { 5534 bp = nbufp(j); 5535 if (bp->b_domain == i && BUF_ISLOCKED(bp)) { 5536 cnt++; 5537 total += bp->b_bufsize; 5538 } 5539 } 5540 db_printf("\tLocked buffers: %d space %ld\n", cnt, total); 5541 cnt = 0; 5542 total = 0; 5543 for (j = 0; j < nbuf; j++) { 5544 bp = nbufp(j); 5545 if (bp->b_domain == i) { 5546 cnt++; 5547 total += bp->b_bufsize; 5548 } 5549 } 5550 db_printf("\tTotal buffers: %d space %ld\n", cnt, total); 5551 } 5552 } 5553 5554 DB_SHOW_COMMAND_FLAGS(lockedbufs, lockedbufs, DB_CMD_MEMSAFE) 5555 { 5556 struct buf *bp; 5557 int i; 5558 5559 for (i = 0; i < nbuf; i++) { 5560 bp = nbufp(i); 5561 if (BUF_ISLOCKED(bp)) { 5562 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5563 db_printf("\n"); 5564 if (db_pager_quit) 5565 break; 5566 } 5567 } 5568 } 5569 5570 DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs) 5571 { 5572 struct vnode *vp; 5573 struct buf *bp; 5574 5575 if (!have_addr) { 5576 db_printf("usage: show vnodebufs <addr>\n"); 5577 return; 5578 } 5579 vp = (struct vnode *)addr; 5580 db_printf("Clean buffers:\n"); 5581 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) { 5582 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5583 db_printf("\n"); 5584 } 5585 db_printf("Dirty buffers:\n"); 5586 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) { 5587 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5588 db_printf("\n"); 5589 } 5590 } 5591 5592 DB_COMMAND_FLAGS(countfreebufs, db_coundfreebufs, DB_CMD_MEMSAFE) 5593 { 5594 struct buf *bp; 5595 int i, used = 0, nfree = 0; 5596 5597 if (have_addr) { 5598 db_printf("usage: countfreebufs\n"); 5599 return; 5600 } 5601 5602 for (i = 0; i < nbuf; i++) { 5603 bp = nbufp(i); 5604 if (bp->b_qindex == QUEUE_EMPTY) 5605 nfree++; 5606 else 5607 used++; 5608 } 5609 5610 db_printf("Counted %d free, %d used (%d tot)\n", nfree, used, 5611 nfree + used); 5612 db_printf("numfreebuffers is %d\n", numfreebuffers); 5613 } 5614 #endif /* DDB */ 5615