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/pctrie.h> 71 #include <sys/proc.h> 72 #include <sys/racct.h> 73 #include <sys/refcount.h> 74 #include <sys/resourcevar.h> 75 #include <sys/rwlock.h> 76 #include <sys/sched.h> 77 #include <sys/smp.h> 78 #include <sys/sysctl.h> 79 #include <sys/syscallsubr.h> 80 #include <sys/vmem.h> 81 #include <sys/vmmeter.h> 82 #include <sys/vnode.h> 83 #include <sys/watchdog.h> 84 #include <geom/geom.h> 85 #include <vm/vm.h> 86 #include <vm/vm_param.h> 87 #include <vm/vm_kern.h> 88 #include <vm/vm_object.h> 89 #include <vm/vm_page.h> 90 #include <vm/vm_pageout.h> 91 #include <vm/vm_pager.h> 92 #include <vm/vm_extern.h> 93 #include <vm/vm_map.h> 94 #include <vm/swap_pager.h> 95 96 static MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer"); 97 98 struct bio_ops bioops; /* I/O operation notification */ 99 100 struct buf_ops buf_ops_bio = { 101 .bop_name = "buf_ops_bio", 102 .bop_write = bufwrite, 103 .bop_strategy = bufstrategy, 104 .bop_sync = bufsync, 105 .bop_bdflush = bufbdflush, 106 }; 107 108 struct bufqueue { 109 struct mtx_padalign bq_lock; 110 TAILQ_HEAD(, buf) bq_queue; 111 uint8_t bq_index; 112 uint16_t bq_subqueue; 113 int bq_len; 114 } __aligned(CACHE_LINE_SIZE); 115 116 #define BQ_LOCKPTR(bq) (&(bq)->bq_lock) 117 #define BQ_LOCK(bq) mtx_lock(BQ_LOCKPTR((bq))) 118 #define BQ_UNLOCK(bq) mtx_unlock(BQ_LOCKPTR((bq))) 119 #define BQ_ASSERT_LOCKED(bq) mtx_assert(BQ_LOCKPTR((bq)), MA_OWNED) 120 121 struct bufdomain { 122 struct bufqueue *bd_subq; 123 struct bufqueue bd_dirtyq; 124 struct bufqueue *bd_cleanq; 125 struct mtx_padalign bd_run_lock; 126 /* Constants */ 127 long bd_maxbufspace; 128 long bd_hibufspace; 129 long bd_lobufspace; 130 long bd_bufspacethresh; 131 int bd_hifreebuffers; 132 int bd_lofreebuffers; 133 int bd_hidirtybuffers; 134 int bd_lodirtybuffers; 135 int bd_dirtybufthresh; 136 int bd_lim; 137 /* atomics */ 138 int bd_wanted; 139 bool bd_shutdown; 140 int __aligned(CACHE_LINE_SIZE) bd_numdirtybuffers; 141 int __aligned(CACHE_LINE_SIZE) bd_running; 142 long __aligned(CACHE_LINE_SIZE) bd_bufspace; 143 int __aligned(CACHE_LINE_SIZE) bd_freebuffers; 144 } __aligned(CACHE_LINE_SIZE); 145 146 #define BD_LOCKPTR(bd) (&(bd)->bd_cleanq->bq_lock) 147 #define BD_LOCK(bd) mtx_lock(BD_LOCKPTR((bd))) 148 #define BD_UNLOCK(bd) mtx_unlock(BD_LOCKPTR((bd))) 149 #define BD_ASSERT_LOCKED(bd) mtx_assert(BD_LOCKPTR((bd)), MA_OWNED) 150 #define BD_RUN_LOCKPTR(bd) (&(bd)->bd_run_lock) 151 #define BD_RUN_LOCK(bd) mtx_lock(BD_RUN_LOCKPTR((bd))) 152 #define BD_RUN_UNLOCK(bd) mtx_unlock(BD_RUN_LOCKPTR((bd))) 153 #define BD_DOMAIN(bd) (bd - bdomain) 154 155 static char *buf; /* buffer header pool */ 156 static struct buf * 157 nbufp(unsigned i) 158 { 159 return ((struct buf *)(buf + (sizeof(struct buf) + 160 sizeof(vm_page_t) * atop(maxbcachebuf)) * i)); 161 } 162 163 caddr_t __read_mostly unmapped_buf; 164 165 /* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.c */ 166 struct proc *bufdaemonproc; 167 168 static void vm_hold_free_pages(struct buf *bp, int newbsize); 169 static void vm_hold_load_pages(struct buf *bp, vm_offset_t from, 170 vm_offset_t to); 171 static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m); 172 static void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, 173 vm_page_t m); 174 static void vfs_clean_pages_dirty_buf(struct buf *bp); 175 static void vfs_setdirty_range(struct buf *bp); 176 static void vfs_vmio_invalidate(struct buf *bp); 177 static void vfs_vmio_truncate(struct buf *bp, int npages); 178 static void vfs_vmio_extend(struct buf *bp, int npages, int size); 179 static int vfs_bio_clcheck(struct vnode *vp, int size, 180 daddr_t lblkno, daddr_t blkno); 181 static void breada(struct vnode *, daddr_t *, int *, int, struct ucred *, int, 182 void (*)(struct buf *)); 183 static int buf_flush(struct vnode *vp, struct bufdomain *, int); 184 static int flushbufqueues(struct vnode *, struct bufdomain *, int, int); 185 static void buf_daemon(void); 186 static __inline void bd_wakeup(void); 187 static int sysctl_runningspace(SYSCTL_HANDLER_ARGS); 188 static void bufkva_reclaim(vmem_t *, int); 189 static void bufkva_free(struct buf *); 190 static int buf_import(void *, void **, int, int, int); 191 static void buf_release(void *, void **, int); 192 static void maxbcachebuf_adjust(void); 193 static inline struct bufdomain *bufdomain(struct buf *); 194 static void bq_remove(struct bufqueue *bq, struct buf *bp); 195 static void bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock); 196 static int buf_recycle(struct bufdomain *, bool kva); 197 static void bq_init(struct bufqueue *bq, int qindex, int cpu, 198 const char *lockname); 199 static void bd_init(struct bufdomain *bd); 200 static int bd_flushall(struct bufdomain *bd); 201 static int sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS); 202 static int sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS); 203 204 static int sysctl_bufspace(SYSCTL_HANDLER_ARGS); 205 int vmiodirenable = TRUE; 206 SYSCTL_INT(_vfs, OID_AUTO, vmiodirenable, CTLFLAG_RW, &vmiodirenable, 0, 207 "Use the VM system for directory writes"); 208 long runningbufspace; 209 SYSCTL_LONG(_vfs, OID_AUTO, runningbufspace, CTLFLAG_RD, &runningbufspace, 0, 210 "Amount of presently outstanding async buffer io"); 211 SYSCTL_PROC(_vfs, OID_AUTO, bufspace, CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RD, 212 NULL, 0, sysctl_bufspace, "L", "Physical memory used for buffers"); 213 static counter_u64_t bufkvaspace; 214 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufkvaspace, CTLFLAG_RD, &bufkvaspace, 215 "Kernel virtual memory used for buffers"); 216 static long maxbufspace; 217 SYSCTL_PROC(_vfs, OID_AUTO, maxbufspace, 218 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &maxbufspace, 219 __offsetof(struct bufdomain, bd_maxbufspace), sysctl_bufdomain_long, "L", 220 "Maximum allowed value of bufspace (including metadata)"); 221 static long bufmallocspace; 222 SYSCTL_LONG(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0, 223 "Amount of malloced memory for buffers"); 224 static long maxbufmallocspace; 225 SYSCTL_LONG(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace, 226 0, "Maximum amount of malloced memory for buffers"); 227 static long lobufspace; 228 SYSCTL_PROC(_vfs, OID_AUTO, lobufspace, 229 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &lobufspace, 230 __offsetof(struct bufdomain, bd_lobufspace), sysctl_bufdomain_long, "L", 231 "Minimum amount of buffers we want to have"); 232 long hibufspace; 233 SYSCTL_PROC(_vfs, OID_AUTO, hibufspace, 234 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &hibufspace, 235 __offsetof(struct bufdomain, bd_hibufspace), sysctl_bufdomain_long, "L", 236 "Maximum allowed value of bufspace (excluding metadata)"); 237 long bufspacethresh; 238 SYSCTL_PROC(_vfs, OID_AUTO, bufspacethresh, 239 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &bufspacethresh, 240 __offsetof(struct bufdomain, bd_bufspacethresh), sysctl_bufdomain_long, "L", 241 "Bufspace consumed before waking the daemon to free some"); 242 static counter_u64_t buffreekvacnt; 243 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, buffreekvacnt, CTLFLAG_RW, &buffreekvacnt, 244 "Number of times we have freed the KVA space from some buffer"); 245 static counter_u64_t bufdefragcnt; 246 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufdefragcnt, CTLFLAG_RW, &bufdefragcnt, 247 "Number of times we have had to repeat buffer allocation to defragment"); 248 static long lorunningspace; 249 SYSCTL_PROC(_vfs, OID_AUTO, lorunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 250 CTLFLAG_RW, &lorunningspace, 0, sysctl_runningspace, "L", 251 "Minimum preferred space used for in-progress I/O"); 252 static long hirunningspace; 253 SYSCTL_PROC(_vfs, OID_AUTO, hirunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 254 CTLFLAG_RW, &hirunningspace, 0, sysctl_runningspace, "L", 255 "Maximum amount of space to use for in-progress I/O"); 256 int dirtybufferflushes; 257 SYSCTL_INT(_vfs, OID_AUTO, dirtybufferflushes, CTLFLAG_RW, &dirtybufferflushes, 258 0, "Number of bdwrite to bawrite conversions to limit dirty buffers"); 259 int bdwriteskip; 260 SYSCTL_INT(_vfs, OID_AUTO, bdwriteskip, CTLFLAG_RW, &bdwriteskip, 261 0, "Number of buffers supplied to bdwrite with snapshot deadlock risk"); 262 int altbufferflushes; 263 SYSCTL_INT(_vfs, OID_AUTO, altbufferflushes, CTLFLAG_RW | CTLFLAG_STATS, 264 &altbufferflushes, 0, "Number of fsync flushes to limit dirty buffers"); 265 static int recursiveflushes; 266 SYSCTL_INT(_vfs, OID_AUTO, recursiveflushes, CTLFLAG_RW | CTLFLAG_STATS, 267 &recursiveflushes, 0, "Number of flushes skipped due to being recursive"); 268 static int sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS); 269 SYSCTL_PROC(_vfs, OID_AUTO, numdirtybuffers, 270 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RD, NULL, 0, sysctl_numdirtybuffers, "I", 271 "Number of buffers that are dirty (has unwritten changes) at the moment"); 272 static int lodirtybuffers; 273 SYSCTL_PROC(_vfs, OID_AUTO, lodirtybuffers, 274 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lodirtybuffers, 275 __offsetof(struct bufdomain, bd_lodirtybuffers), sysctl_bufdomain_int, "I", 276 "How many buffers we want to have free before bufdaemon can sleep"); 277 static int hidirtybuffers; 278 SYSCTL_PROC(_vfs, OID_AUTO, hidirtybuffers, 279 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hidirtybuffers, 280 __offsetof(struct bufdomain, bd_hidirtybuffers), sysctl_bufdomain_int, "I", 281 "When the number of dirty buffers is considered severe"); 282 int dirtybufthresh; 283 SYSCTL_PROC(_vfs, OID_AUTO, dirtybufthresh, 284 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &dirtybufthresh, 285 __offsetof(struct bufdomain, bd_dirtybufthresh), sysctl_bufdomain_int, "I", 286 "Number of bdwrite to bawrite conversions to clear dirty buffers"); 287 static int numfreebuffers; 288 SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0, 289 "Number of free buffers"); 290 static int lofreebuffers; 291 SYSCTL_PROC(_vfs, OID_AUTO, lofreebuffers, 292 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lofreebuffers, 293 __offsetof(struct bufdomain, bd_lofreebuffers), sysctl_bufdomain_int, "I", 294 "Target number of free buffers"); 295 static int hifreebuffers; 296 SYSCTL_PROC(_vfs, OID_AUTO, hifreebuffers, 297 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hifreebuffers, 298 __offsetof(struct bufdomain, bd_hifreebuffers), sysctl_bufdomain_int, "I", 299 "Threshold for clean buffer recycling"); 300 static counter_u64_t getnewbufcalls; 301 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufcalls, CTLFLAG_RD, 302 &getnewbufcalls, "Number of calls to getnewbuf"); 303 static counter_u64_t getnewbufrestarts; 304 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufrestarts, CTLFLAG_RD, 305 &getnewbufrestarts, 306 "Number of times getnewbuf has had to restart a buffer acquisition"); 307 static counter_u64_t mappingrestarts; 308 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, mappingrestarts, CTLFLAG_RD, 309 &mappingrestarts, 310 "Number of times getblk has had to restart a buffer mapping for " 311 "unmapped buffer"); 312 static counter_u64_t numbufallocfails; 313 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, numbufallocfails, CTLFLAG_RW, 314 &numbufallocfails, "Number of times buffer allocations failed"); 315 static int flushbufqtarget = 100; 316 SYSCTL_INT(_vfs, OID_AUTO, flushbufqtarget, CTLFLAG_RW, &flushbufqtarget, 0, 317 "Amount of work to do in flushbufqueues when helping bufdaemon"); 318 static counter_u64_t notbufdflushes; 319 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, notbufdflushes, CTLFLAG_RD, ¬bufdflushes, 320 "Number of dirty buffer flushes done by the bufdaemon helpers"); 321 static long barrierwrites; 322 SYSCTL_LONG(_vfs, OID_AUTO, barrierwrites, CTLFLAG_RW | CTLFLAG_STATS, 323 &barrierwrites, 0, "Number of barrier writes"); 324 SYSCTL_INT(_vfs, OID_AUTO, unmapped_buf_allowed, CTLFLAG_RD, 325 &unmapped_buf_allowed, 0, 326 "Permit the use of the unmapped i/o"); 327 int maxbcachebuf = MAXBCACHEBUF; 328 SYSCTL_INT(_vfs, OID_AUTO, maxbcachebuf, CTLFLAG_RDTUN, &maxbcachebuf, 0, 329 "Maximum size of a buffer cache block"); 330 331 /* 332 * This lock synchronizes access to bd_request. 333 */ 334 static struct mtx_padalign __exclusive_cache_line bdlock; 335 336 /* 337 * This lock protects the runningbufreq and synchronizes runningbufwakeup and 338 * waitrunningbufspace(). 339 */ 340 static struct mtx_padalign __exclusive_cache_line rbreqlock; 341 342 /* 343 * Lock that protects bdirtywait. 344 */ 345 static struct mtx_padalign __exclusive_cache_line bdirtylock; 346 347 /* 348 * bufdaemon shutdown request and sleep channel. 349 */ 350 static bool bd_shutdown; 351 352 /* 353 * Wakeup point for bufdaemon, as well as indicator of whether it is already 354 * active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it 355 * is idling. 356 */ 357 static int bd_request; 358 359 /* 360 * Request for the buf daemon to write more buffers than is indicated by 361 * lodirtybuf. This may be necessary to push out excess dependencies or 362 * defragment the address space where a simple count of the number of dirty 363 * buffers is insufficient to characterize the demand for flushing them. 364 */ 365 static int bd_speedupreq; 366 367 /* 368 * Synchronization (sleep/wakeup) variable for active buffer space requests. 369 * Set when wait starts, cleared prior to wakeup(). 370 * Used in runningbufwakeup() and waitrunningbufspace(). 371 */ 372 static int runningbufreq; 373 374 /* 375 * Synchronization for bwillwrite() waiters. 376 */ 377 static int bdirtywait; 378 379 /* 380 * Definitions for the buffer free lists. 381 */ 382 #define QUEUE_NONE 0 /* on no queue */ 383 #define QUEUE_EMPTY 1 /* empty buffer headers */ 384 #define QUEUE_DIRTY 2 /* B_DELWRI buffers */ 385 #define QUEUE_CLEAN 3 /* non-B_DELWRI buffers */ 386 #define QUEUE_SENTINEL 4 /* not an queue index, but mark for sentinel */ 387 388 /* Maximum number of buffer domains. */ 389 #define BUF_DOMAINS 8 390 391 struct bufdomainset bdlodirty; /* Domains > lodirty */ 392 struct bufdomainset bdhidirty; /* Domains > hidirty */ 393 394 /* Configured number of clean queues. */ 395 static int __read_mostly buf_domains; 396 397 BITSET_DEFINE(bufdomainset, BUF_DOMAINS); 398 struct bufdomain __exclusive_cache_line bdomain[BUF_DOMAINS]; 399 struct bufqueue __exclusive_cache_line bqempty; 400 401 /* 402 * per-cpu empty buffer cache. 403 */ 404 uma_zone_t buf_zone; 405 406 static int 407 sysctl_runningspace(SYSCTL_HANDLER_ARGS) 408 { 409 long value; 410 int error; 411 412 value = *(long *)arg1; 413 error = sysctl_handle_long(oidp, &value, 0, req); 414 if (error != 0 || req->newptr == NULL) 415 return (error); 416 mtx_lock(&rbreqlock); 417 if (arg1 == &hirunningspace) { 418 if (value < lorunningspace) 419 error = EINVAL; 420 else 421 hirunningspace = value; 422 } else { 423 KASSERT(arg1 == &lorunningspace, 424 ("%s: unknown arg1", __func__)); 425 if (value > hirunningspace) 426 error = EINVAL; 427 else 428 lorunningspace = value; 429 } 430 mtx_unlock(&rbreqlock); 431 return (error); 432 } 433 434 static int 435 sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS) 436 { 437 int error; 438 int value; 439 int i; 440 441 value = *(int *)arg1; 442 error = sysctl_handle_int(oidp, &value, 0, req); 443 if (error != 0 || req->newptr == NULL) 444 return (error); 445 *(int *)arg1 = value; 446 for (i = 0; i < buf_domains; i++) 447 *(int *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 448 value / buf_domains; 449 450 return (error); 451 } 452 453 static int 454 sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS) 455 { 456 long value; 457 int error; 458 int i; 459 460 value = *(long *)arg1; 461 error = sysctl_handle_long(oidp, &value, 0, req); 462 if (error != 0 || req->newptr == NULL) 463 return (error); 464 *(long *)arg1 = value; 465 for (i = 0; i < buf_domains; i++) 466 *(long *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 467 value / buf_domains; 468 469 return (error); 470 } 471 472 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 473 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 474 static int 475 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 476 { 477 long lvalue; 478 int ivalue; 479 int i; 480 481 lvalue = 0; 482 for (i = 0; i < buf_domains; i++) 483 lvalue += bdomain[i].bd_bufspace; 484 if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long)) 485 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 486 if (lvalue > INT_MAX) 487 /* On overflow, still write out a long to trigger ENOMEM. */ 488 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 489 ivalue = lvalue; 490 return (sysctl_handle_int(oidp, &ivalue, 0, req)); 491 } 492 #else 493 static int 494 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 495 { 496 long lvalue; 497 int i; 498 499 lvalue = 0; 500 for (i = 0; i < buf_domains; i++) 501 lvalue += bdomain[i].bd_bufspace; 502 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 503 } 504 #endif 505 506 static int 507 sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS) 508 { 509 int value; 510 int i; 511 512 value = 0; 513 for (i = 0; i < buf_domains; i++) 514 value += bdomain[i].bd_numdirtybuffers; 515 return (sysctl_handle_int(oidp, &value, 0, req)); 516 } 517 518 /* 519 * bdirtywakeup: 520 * 521 * Wakeup any bwillwrite() waiters. 522 */ 523 static void 524 bdirtywakeup(void) 525 { 526 mtx_lock(&bdirtylock); 527 if (bdirtywait) { 528 bdirtywait = 0; 529 wakeup(&bdirtywait); 530 } 531 mtx_unlock(&bdirtylock); 532 } 533 534 /* 535 * bd_clear: 536 * 537 * Clear a domain from the appropriate bitsets when dirtybuffers 538 * is decremented. 539 */ 540 static void 541 bd_clear(struct bufdomain *bd) 542 { 543 544 mtx_lock(&bdirtylock); 545 if (bd->bd_numdirtybuffers <= bd->bd_lodirtybuffers) 546 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 547 if (bd->bd_numdirtybuffers <= bd->bd_hidirtybuffers) 548 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 549 mtx_unlock(&bdirtylock); 550 } 551 552 /* 553 * bd_set: 554 * 555 * Set a domain in the appropriate bitsets when dirtybuffers 556 * is incremented. 557 */ 558 static void 559 bd_set(struct bufdomain *bd) 560 { 561 562 mtx_lock(&bdirtylock); 563 if (bd->bd_numdirtybuffers > bd->bd_lodirtybuffers) 564 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 565 if (bd->bd_numdirtybuffers > bd->bd_hidirtybuffers) 566 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 567 mtx_unlock(&bdirtylock); 568 } 569 570 /* 571 * bdirtysub: 572 * 573 * Decrement the numdirtybuffers count by one and wakeup any 574 * threads blocked in bwillwrite(). 575 */ 576 static void 577 bdirtysub(struct buf *bp) 578 { 579 struct bufdomain *bd; 580 int num; 581 582 bd = bufdomain(bp); 583 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, -1); 584 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 585 bdirtywakeup(); 586 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 587 bd_clear(bd); 588 } 589 590 /* 591 * bdirtyadd: 592 * 593 * Increment the numdirtybuffers count by one and wakeup the buf 594 * daemon if needed. 595 */ 596 static void 597 bdirtyadd(struct buf *bp) 598 { 599 struct bufdomain *bd; 600 int num; 601 602 /* 603 * Only do the wakeup once as we cross the boundary. The 604 * buf daemon will keep running until the condition clears. 605 */ 606 bd = bufdomain(bp); 607 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, 1); 608 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 609 bd_wakeup(); 610 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 611 bd_set(bd); 612 } 613 614 /* 615 * bufspace_daemon_wakeup: 616 * 617 * Wakeup the daemons responsible for freeing clean bufs. 618 */ 619 static void 620 bufspace_daemon_wakeup(struct bufdomain *bd) 621 { 622 623 /* 624 * avoid the lock if the daemon is running. 625 */ 626 if (atomic_fetchadd_int(&bd->bd_running, 1) == 0) { 627 BD_RUN_LOCK(bd); 628 atomic_store_int(&bd->bd_running, 1); 629 wakeup(&bd->bd_running); 630 BD_RUN_UNLOCK(bd); 631 } 632 } 633 634 /* 635 * bufspace_adjust: 636 * 637 * Adjust the reported bufspace for a KVA managed buffer, possibly 638 * waking any waiters. 639 */ 640 static void 641 bufspace_adjust(struct buf *bp, int bufsize) 642 { 643 struct bufdomain *bd; 644 long space; 645 int diff; 646 647 KASSERT((bp->b_flags & B_MALLOC) == 0, 648 ("bufspace_adjust: malloc buf %p", bp)); 649 bd = bufdomain(bp); 650 diff = bufsize - bp->b_bufsize; 651 if (diff < 0) { 652 atomic_subtract_long(&bd->bd_bufspace, -diff); 653 } else if (diff > 0) { 654 space = atomic_fetchadd_long(&bd->bd_bufspace, diff); 655 /* Wake up the daemon on the transition. */ 656 if (space < bd->bd_bufspacethresh && 657 space + diff >= bd->bd_bufspacethresh) 658 bufspace_daemon_wakeup(bd); 659 } 660 bp->b_bufsize = bufsize; 661 } 662 663 /* 664 * bufspace_reserve: 665 * 666 * Reserve bufspace before calling allocbuf(). metadata has a 667 * different space limit than data. 668 */ 669 static int 670 bufspace_reserve(struct bufdomain *bd, int size, bool metadata) 671 { 672 long limit, new; 673 long space; 674 675 if (metadata) 676 limit = bd->bd_maxbufspace; 677 else 678 limit = bd->bd_hibufspace; 679 space = atomic_fetchadd_long(&bd->bd_bufspace, size); 680 new = space + size; 681 if (new > limit) { 682 atomic_subtract_long(&bd->bd_bufspace, size); 683 return (ENOSPC); 684 } 685 686 /* Wake up the daemon on the transition. */ 687 if (space < bd->bd_bufspacethresh && new >= bd->bd_bufspacethresh) 688 bufspace_daemon_wakeup(bd); 689 690 return (0); 691 } 692 693 /* 694 * bufspace_release: 695 * 696 * Release reserved bufspace after bufspace_adjust() has consumed it. 697 */ 698 static void 699 bufspace_release(struct bufdomain *bd, int size) 700 { 701 702 atomic_subtract_long(&bd->bd_bufspace, size); 703 } 704 705 /* 706 * bufspace_wait: 707 * 708 * Wait for bufspace, acting as the buf daemon if a locked vnode is 709 * supplied. bd_wanted must be set prior to polling for space. The 710 * operation must be re-tried on return. 711 */ 712 static void 713 bufspace_wait(struct bufdomain *bd, struct vnode *vp, int gbflags, 714 int slpflag, int slptimeo) 715 { 716 struct thread *td; 717 int error, fl, norunbuf; 718 719 if ((gbflags & GB_NOWAIT_BD) != 0) 720 return; 721 722 td = curthread; 723 BD_LOCK(bd); 724 while (bd->bd_wanted) { 725 if (vp != NULL && vp->v_type != VCHR && 726 (td->td_pflags & TDP_BUFNEED) == 0) { 727 BD_UNLOCK(bd); 728 /* 729 * getblk() is called with a vnode locked, and 730 * some majority of the dirty buffers may as 731 * well belong to the vnode. Flushing the 732 * buffers there would make a progress that 733 * cannot be achieved by the buf_daemon, that 734 * cannot lock the vnode. 735 */ 736 norunbuf = ~(TDP_BUFNEED | TDP_NORUNNINGBUF) | 737 (td->td_pflags & TDP_NORUNNINGBUF); 738 739 /* 740 * Play bufdaemon. The getnewbuf() function 741 * may be called while the thread owns lock 742 * for another dirty buffer for the same 743 * vnode, which makes it impossible to use 744 * VOP_FSYNC() there, due to the buffer lock 745 * recursion. 746 */ 747 td->td_pflags |= TDP_BUFNEED | TDP_NORUNNINGBUF; 748 fl = buf_flush(vp, bd, flushbufqtarget); 749 td->td_pflags &= norunbuf; 750 BD_LOCK(bd); 751 if (fl != 0) 752 continue; 753 if (bd->bd_wanted == 0) 754 break; 755 } 756 error = msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 757 (PRIBIO + 4) | slpflag, "newbuf", slptimeo); 758 if (error != 0) 759 break; 760 } 761 BD_UNLOCK(bd); 762 } 763 764 static void 765 bufspace_daemon_shutdown(void *arg, int howto __unused) 766 { 767 struct bufdomain *bd = arg; 768 int error; 769 770 if (KERNEL_PANICKED()) 771 return; 772 773 BD_RUN_LOCK(bd); 774 bd->bd_shutdown = true; 775 wakeup(&bd->bd_running); 776 error = msleep(&bd->bd_shutdown, BD_RUN_LOCKPTR(bd), 0, 777 "bufspace_shutdown", 60 * hz); 778 BD_RUN_UNLOCK(bd); 779 if (error != 0) 780 printf("bufspacedaemon wait error: %d\n", error); 781 } 782 783 /* 784 * bufspace_daemon: 785 * 786 * buffer space management daemon. Tries to maintain some marginal 787 * amount of free buffer space so that requesting processes neither 788 * block nor work to reclaim buffers. 789 */ 790 static void 791 bufspace_daemon(void *arg) 792 { 793 struct bufdomain *bd = arg; 794 795 EVENTHANDLER_REGISTER(shutdown_pre_sync, bufspace_daemon_shutdown, bd, 796 SHUTDOWN_PRI_LAST + 100); 797 798 BD_RUN_LOCK(bd); 799 while (!bd->bd_shutdown) { 800 BD_RUN_UNLOCK(bd); 801 802 /* 803 * Free buffers from the clean queue until we meet our 804 * targets. 805 * 806 * Theory of operation: The buffer cache is most efficient 807 * when some free buffer headers and space are always 808 * available to getnewbuf(). This daemon attempts to prevent 809 * the excessive blocking and synchronization associated 810 * with shortfall. It goes through three phases according 811 * demand: 812 * 813 * 1) The daemon wakes up voluntarily once per-second 814 * during idle periods when the counters are below 815 * the wakeup thresholds (bufspacethresh, lofreebuffers). 816 * 817 * 2) The daemon wakes up as we cross the thresholds 818 * ahead of any potential blocking. This may bounce 819 * slightly according to the rate of consumption and 820 * release. 821 * 822 * 3) The daemon and consumers are starved for working 823 * clean buffers. This is the 'bufspace' sleep below 824 * which will inefficiently trade bufs with bqrelse 825 * until we return to condition 2. 826 */ 827 while (bd->bd_bufspace > bd->bd_lobufspace || 828 bd->bd_freebuffers < bd->bd_hifreebuffers) { 829 if (buf_recycle(bd, false) != 0) { 830 if (bd_flushall(bd)) 831 continue; 832 /* 833 * Speedup dirty if we've run out of clean 834 * buffers. This is possible in particular 835 * because softdep may held many bufs locked 836 * pending writes to other bufs which are 837 * marked for delayed write, exhausting 838 * clean space until they are written. 839 */ 840 bd_speedup(); 841 BD_LOCK(bd); 842 if (bd->bd_wanted) { 843 msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 844 PRIBIO|PDROP, "bufspace", hz/10); 845 } else 846 BD_UNLOCK(bd); 847 } 848 maybe_yield(); 849 } 850 851 /* 852 * Re-check our limits and sleep. bd_running must be 853 * cleared prior to checking the limits to avoid missed 854 * wakeups. The waker will adjust one of bufspace or 855 * freebuffers prior to checking bd_running. 856 */ 857 BD_RUN_LOCK(bd); 858 if (bd->bd_shutdown) 859 break; 860 atomic_store_int(&bd->bd_running, 0); 861 if (bd->bd_bufspace < bd->bd_bufspacethresh && 862 bd->bd_freebuffers > bd->bd_lofreebuffers) { 863 msleep(&bd->bd_running, BD_RUN_LOCKPTR(bd), 864 PRIBIO, "-", hz); 865 } else { 866 /* Avoid spurious wakeups while running. */ 867 atomic_store_int(&bd->bd_running, 1); 868 } 869 } 870 wakeup(&bd->bd_shutdown); 871 BD_RUN_UNLOCK(bd); 872 kthread_exit(); 873 } 874 875 /* 876 * bufmallocadjust: 877 * 878 * Adjust the reported bufspace for a malloc managed buffer, possibly 879 * waking any waiters. 880 */ 881 static void 882 bufmallocadjust(struct buf *bp, int bufsize) 883 { 884 int diff; 885 886 KASSERT((bp->b_flags & B_MALLOC) != 0, 887 ("bufmallocadjust: non-malloc buf %p", bp)); 888 diff = bufsize - bp->b_bufsize; 889 if (diff < 0) 890 atomic_subtract_long(&bufmallocspace, -diff); 891 else 892 atomic_add_long(&bufmallocspace, diff); 893 bp->b_bufsize = bufsize; 894 } 895 896 /* 897 * runningwakeup: 898 * 899 * Wake up processes that are waiting on asynchronous writes to fall 900 * below lorunningspace. 901 */ 902 static void 903 runningwakeup(void) 904 { 905 906 mtx_lock(&rbreqlock); 907 if (runningbufreq) { 908 runningbufreq = 0; 909 wakeup(&runningbufreq); 910 } 911 mtx_unlock(&rbreqlock); 912 } 913 914 /* 915 * runningbufwakeup: 916 * 917 * Decrement the outstanding write count according. 918 */ 919 void 920 runningbufwakeup(struct buf *bp) 921 { 922 long space, bspace; 923 924 bspace = bp->b_runningbufspace; 925 if (bspace == 0) 926 return; 927 space = atomic_fetchadd_long(&runningbufspace, -bspace); 928 KASSERT(space >= bspace, ("runningbufspace underflow %ld %ld", 929 space, bspace)); 930 bp->b_runningbufspace = 0; 931 /* 932 * Only acquire the lock and wakeup on the transition from exceeding 933 * the threshold to falling below it. 934 */ 935 if (space < lorunningspace) 936 return; 937 if (space - bspace > lorunningspace) 938 return; 939 runningwakeup(); 940 } 941 942 /* 943 * waitrunningbufspace() 944 * 945 * runningbufspace is a measure of the amount of I/O currently 946 * running. This routine is used in async-write situations to 947 * prevent creating huge backups of pending writes to a device. 948 * Only asynchronous writes are governed by this function. 949 * 950 * This does NOT turn an async write into a sync write. It waits 951 * for earlier writes to complete and generally returns before the 952 * caller's write has reached the device. 953 */ 954 void 955 waitrunningbufspace(void) 956 { 957 958 mtx_lock(&rbreqlock); 959 while (runningbufspace > hirunningspace) { 960 runningbufreq = 1; 961 msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0); 962 } 963 mtx_unlock(&rbreqlock); 964 } 965 966 /* 967 * vfs_buf_test_cache: 968 * 969 * Called when a buffer is extended. This function clears the B_CACHE 970 * bit if the newly extended portion of the buffer does not contain 971 * valid data. 972 */ 973 static __inline void 974 vfs_buf_test_cache(struct buf *bp, vm_ooffset_t foff, vm_offset_t off, 975 vm_offset_t size, vm_page_t m) 976 { 977 978 /* 979 * This function and its results are protected by higher level 980 * synchronization requiring vnode and buf locks to page in and 981 * validate pages. 982 */ 983 if (bp->b_flags & B_CACHE) { 984 int base = (foff + off) & PAGE_MASK; 985 if (vm_page_is_valid(m, base, size) == 0) 986 bp->b_flags &= ~B_CACHE; 987 } 988 } 989 990 /* Wake up the buffer daemon if necessary */ 991 static void 992 bd_wakeup(void) 993 { 994 995 mtx_lock(&bdlock); 996 if (bd_request == 0) { 997 bd_request = 1; 998 wakeup(&bd_request); 999 } 1000 mtx_unlock(&bdlock); 1001 } 1002 1003 /* 1004 * Adjust the maxbcachbuf tunable. 1005 */ 1006 static void 1007 maxbcachebuf_adjust(void) 1008 { 1009 int i; 1010 1011 /* 1012 * maxbcachebuf must be a power of 2 >= MAXBSIZE. 1013 */ 1014 i = 2; 1015 while (i * 2 <= maxbcachebuf) 1016 i *= 2; 1017 maxbcachebuf = i; 1018 if (maxbcachebuf < MAXBSIZE) 1019 maxbcachebuf = MAXBSIZE; 1020 if (maxbcachebuf > maxphys) 1021 maxbcachebuf = maxphys; 1022 if (bootverbose != 0 && maxbcachebuf != MAXBCACHEBUF) 1023 printf("maxbcachebuf=%d\n", maxbcachebuf); 1024 } 1025 1026 /* 1027 * bd_speedup - speedup the buffer cache flushing code 1028 */ 1029 void 1030 bd_speedup(void) 1031 { 1032 int needwake; 1033 1034 mtx_lock(&bdlock); 1035 needwake = 0; 1036 if (bd_speedupreq == 0 || bd_request == 0) 1037 needwake = 1; 1038 bd_speedupreq = 1; 1039 bd_request = 1; 1040 if (needwake) 1041 wakeup(&bd_request); 1042 mtx_unlock(&bdlock); 1043 } 1044 1045 #ifdef __i386__ 1046 #define TRANSIENT_DENOM 5 1047 #else 1048 #define TRANSIENT_DENOM 10 1049 #endif 1050 1051 /* 1052 * Calculating buffer cache scaling values and reserve space for buffer 1053 * headers. This is called during low level kernel initialization and 1054 * may be called more then once. We CANNOT write to the memory area 1055 * being reserved at this time. 1056 */ 1057 caddr_t 1058 kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est) 1059 { 1060 int tuned_nbuf; 1061 long maxbuf, maxbuf_sz, buf_sz, biotmap_sz; 1062 1063 /* 1064 * With KASAN or KMSAN enabled, the kernel map is shadowed. Account for 1065 * this when sizing maps based on the amount of physical memory 1066 * available. 1067 */ 1068 #if defined(KASAN) 1069 physmem_est = (physmem_est * KASAN_SHADOW_SCALE) / 1070 (KASAN_SHADOW_SCALE + 1); 1071 #elif defined(KMSAN) 1072 physmem_est /= 3; 1073 1074 /* 1075 * KMSAN cannot reliably determine whether buffer data is initialized 1076 * unless it is updated through a KVA mapping. 1077 */ 1078 unmapped_buf_allowed = 0; 1079 #endif 1080 1081 /* 1082 * physmem_est is in pages. Convert it to kilobytes (assumes 1083 * PAGE_SIZE is >= 1K) 1084 */ 1085 physmem_est = physmem_est * (PAGE_SIZE / 1024); 1086 1087 maxbcachebuf_adjust(); 1088 /* 1089 * The nominal buffer size (and minimum KVA allocation) is BKVASIZE. 1090 * For the first 64MB of ram nominally allocate sufficient buffers to 1091 * cover 1/4 of our ram. Beyond the first 64MB allocate additional 1092 * buffers to cover 1/10 of our ram over 64MB. When auto-sizing 1093 * the buffer cache we limit the eventual kva reservation to 1094 * maxbcache bytes. 1095 * 1096 * factor represents the 1/4 x ram conversion. 1097 */ 1098 if (nbuf == 0) { 1099 int factor = 4 * BKVASIZE / 1024; 1100 1101 nbuf = 50; 1102 if (physmem_est > 4096) 1103 nbuf += min((physmem_est - 4096) / factor, 1104 65536 / factor); 1105 if (physmem_est > 65536) 1106 nbuf += min((physmem_est - 65536) * 2 / (factor * 5), 1107 32 * 1024 * 1024 / (factor * 5)); 1108 1109 if (maxbcache && nbuf > maxbcache / BKVASIZE) 1110 nbuf = maxbcache / BKVASIZE; 1111 tuned_nbuf = 1; 1112 } else 1113 tuned_nbuf = 0; 1114 1115 /* XXX Avoid unsigned long overflows later on with maxbufspace. */ 1116 maxbuf = (LONG_MAX / 3) / BKVASIZE; 1117 if (nbuf > maxbuf) { 1118 if (!tuned_nbuf) 1119 printf("Warning: nbufs lowered from %d to %ld\n", nbuf, 1120 maxbuf); 1121 nbuf = maxbuf; 1122 } 1123 1124 /* 1125 * Ideal allocation size for the transient bio submap is 10% 1126 * of the maximal space buffer map. This roughly corresponds 1127 * to the amount of the buffer mapped for typical UFS load. 1128 * 1129 * Clip the buffer map to reserve space for the transient 1130 * BIOs, if its extent is bigger than 90% (80% on i386) of the 1131 * maximum buffer map extent on the platform. 1132 * 1133 * The fall-back to the maxbuf in case of maxbcache unset, 1134 * allows to not trim the buffer KVA for the architectures 1135 * with ample KVA space. 1136 */ 1137 if (bio_transient_maxcnt == 0 && unmapped_buf_allowed) { 1138 maxbuf_sz = maxbcache != 0 ? maxbcache : maxbuf * BKVASIZE; 1139 buf_sz = (long)nbuf * BKVASIZE; 1140 if (buf_sz < maxbuf_sz / TRANSIENT_DENOM * 1141 (TRANSIENT_DENOM - 1)) { 1142 /* 1143 * There is more KVA than memory. Do not 1144 * adjust buffer map size, and assign the rest 1145 * of maxbuf to transient map. 1146 */ 1147 biotmap_sz = maxbuf_sz - buf_sz; 1148 } else { 1149 /* 1150 * Buffer map spans all KVA we could afford on 1151 * this platform. Give 10% (20% on i386) of 1152 * the buffer map to the transient bio map. 1153 */ 1154 biotmap_sz = buf_sz / TRANSIENT_DENOM; 1155 buf_sz -= biotmap_sz; 1156 } 1157 if (biotmap_sz / INT_MAX > maxphys) 1158 bio_transient_maxcnt = INT_MAX; 1159 else 1160 bio_transient_maxcnt = biotmap_sz / maxphys; 1161 /* 1162 * Artificially limit to 1024 simultaneous in-flight I/Os 1163 * using the transient mapping. 1164 */ 1165 if (bio_transient_maxcnt > 1024) 1166 bio_transient_maxcnt = 1024; 1167 if (tuned_nbuf) 1168 nbuf = buf_sz / BKVASIZE; 1169 } 1170 1171 if (nswbuf == 0) { 1172 /* 1173 * Pager buffers are allocated for short periods, so scale the 1174 * number of reserved buffers based on the number of CPUs rather 1175 * than amount of memory. 1176 */ 1177 nswbuf = min(nbuf / 4, 32 * mp_ncpus); 1178 if (nswbuf < NSWBUF_MIN) 1179 nswbuf = NSWBUF_MIN; 1180 } 1181 1182 /* 1183 * Reserve space for the buffer cache buffers 1184 */ 1185 buf = (char *)v; 1186 v = (caddr_t)buf + (sizeof(struct buf) + sizeof(vm_page_t) * 1187 atop(maxbcachebuf)) * nbuf; 1188 1189 return (v); 1190 } 1191 1192 /* 1193 * Single global constant for BUF_WMESG, to avoid getting multiple 1194 * references. 1195 */ 1196 static const char buf_wmesg[] = "bufwait"; 1197 1198 /* Initialize the buffer subsystem. Called before use of any buffers. */ 1199 void 1200 bufinit(void) 1201 { 1202 struct buf *bp; 1203 int i; 1204 1205 TSENTER(); 1206 KASSERT(maxbcachebuf >= MAXBSIZE, 1207 ("maxbcachebuf (%d) must be >= MAXBSIZE (%d)\n", maxbcachebuf, 1208 MAXBSIZE)); 1209 bq_init(&bqempty, QUEUE_EMPTY, -1, "bufq empty lock"); 1210 mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF); 1211 mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF); 1212 mtx_init(&bdirtylock, "dirty buf lock", NULL, MTX_DEF); 1213 1214 unmapped_buf = (caddr_t)kva_alloc(maxphys); 1215 1216 /* finally, initialize each buffer header and stick on empty q */ 1217 for (i = 0; i < nbuf; i++) { 1218 bp = nbufp(i); 1219 bzero(bp, sizeof(*bp) + sizeof(vm_page_t) * atop(maxbcachebuf)); 1220 bp->b_flags = B_INVAL; 1221 bp->b_rcred = NOCRED; 1222 bp->b_wcred = NOCRED; 1223 bp->b_qindex = QUEUE_NONE; 1224 bp->b_domain = -1; 1225 bp->b_subqueue = mp_maxid + 1; 1226 bp->b_xflags = 0; 1227 bp->b_data = bp->b_kvabase = unmapped_buf; 1228 LIST_INIT(&bp->b_dep); 1229 BUF_LOCKINIT(bp, buf_wmesg); 1230 bq_insert(&bqempty, bp, false); 1231 } 1232 1233 /* 1234 * maxbufspace is the absolute maximum amount of buffer space we are 1235 * allowed to reserve in KVM and in real terms. The absolute maximum 1236 * is nominally used by metadata. hibufspace is the nominal maximum 1237 * used by most other requests. The differential is required to 1238 * ensure that metadata deadlocks don't occur. 1239 * 1240 * maxbufspace is based on BKVASIZE. Allocating buffers larger then 1241 * this may result in KVM fragmentation which is not handled optimally 1242 * by the system. XXX This is less true with vmem. We could use 1243 * PAGE_SIZE. 1244 */ 1245 maxbufspace = (long)nbuf * BKVASIZE; 1246 hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - maxbcachebuf * 10); 1247 lobufspace = (hibufspace / 20) * 19; /* 95% */ 1248 bufspacethresh = lobufspace + (hibufspace - lobufspace) / 2; 1249 1250 /* 1251 * Note: The 16 MiB upper limit for hirunningspace was chosen 1252 * arbitrarily and may need further tuning. It corresponds to 1253 * 128 outstanding write IO requests (if IO size is 128 KiB), 1254 * which fits with many RAID controllers' tagged queuing limits. 1255 * The lower 1 MiB limit is the historical upper limit for 1256 * hirunningspace. 1257 */ 1258 hirunningspace = lmax(lmin(roundup(hibufspace / 64, maxbcachebuf), 1259 16 * 1024 * 1024), 1024 * 1024); 1260 lorunningspace = roundup((hirunningspace * 2) / 3, maxbcachebuf); 1261 1262 /* 1263 * Limit the amount of malloc memory since it is wired permanently into 1264 * the kernel space. Even though this is accounted for in the buffer 1265 * allocation, we don't want the malloced region to grow uncontrolled. 1266 * The malloc scheme improves memory utilization significantly on 1267 * average (small) directories. 1268 */ 1269 maxbufmallocspace = hibufspace / 20; 1270 1271 /* 1272 * Reduce the chance of a deadlock occurring by limiting the number 1273 * of delayed-write dirty buffers we allow to stack up. 1274 */ 1275 hidirtybuffers = nbuf / 4 + 20; 1276 dirtybufthresh = hidirtybuffers * 9 / 10; 1277 /* 1278 * To support extreme low-memory systems, make sure hidirtybuffers 1279 * cannot eat up all available buffer space. This occurs when our 1280 * minimum cannot be met. We try to size hidirtybuffers to 3/4 our 1281 * buffer space assuming BKVASIZE'd buffers. 1282 */ 1283 while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) { 1284 hidirtybuffers >>= 1; 1285 } 1286 lodirtybuffers = hidirtybuffers / 2; 1287 1288 /* 1289 * lofreebuffers should be sufficient to avoid stalling waiting on 1290 * buf headers under heavy utilization. The bufs in per-cpu caches 1291 * are counted as free but will be unavailable to threads executing 1292 * on other cpus. 1293 * 1294 * hifreebuffers is the free target for the bufspace daemon. This 1295 * should be set appropriately to limit work per-iteration. 1296 */ 1297 lofreebuffers = MIN((nbuf / 25) + (20 * mp_ncpus), 128 * mp_ncpus); 1298 hifreebuffers = (3 * lofreebuffers) / 2; 1299 numfreebuffers = nbuf; 1300 1301 /* Setup the kva and free list allocators. */ 1302 vmem_set_reclaim(buffer_arena, bufkva_reclaim); 1303 buf_zone = uma_zcache_create("buf free cache", 1304 sizeof(struct buf) + sizeof(vm_page_t) * atop(maxbcachebuf), 1305 NULL, NULL, NULL, NULL, buf_import, buf_release, NULL, 0); 1306 1307 /* 1308 * Size the clean queue according to the amount of buffer space. 1309 * One queue per-256mb up to the max. More queues gives better 1310 * concurrency but less accurate LRU. 1311 */ 1312 buf_domains = MIN(howmany(maxbufspace, 256*1024*1024), BUF_DOMAINS); 1313 for (i = 0 ; i < buf_domains; i++) { 1314 struct bufdomain *bd; 1315 1316 bd = &bdomain[i]; 1317 bd_init(bd); 1318 bd->bd_freebuffers = nbuf / buf_domains; 1319 bd->bd_hifreebuffers = hifreebuffers / buf_domains; 1320 bd->bd_lofreebuffers = lofreebuffers / buf_domains; 1321 bd->bd_bufspace = 0; 1322 bd->bd_maxbufspace = maxbufspace / buf_domains; 1323 bd->bd_hibufspace = hibufspace / buf_domains; 1324 bd->bd_lobufspace = lobufspace / buf_domains; 1325 bd->bd_bufspacethresh = bufspacethresh / buf_domains; 1326 bd->bd_numdirtybuffers = 0; 1327 bd->bd_hidirtybuffers = hidirtybuffers / buf_domains; 1328 bd->bd_lodirtybuffers = lodirtybuffers / buf_domains; 1329 bd->bd_dirtybufthresh = dirtybufthresh / buf_domains; 1330 /* Don't allow more than 2% of bufs in the per-cpu caches. */ 1331 bd->bd_lim = nbuf / buf_domains / 50 / mp_ncpus; 1332 } 1333 getnewbufcalls = counter_u64_alloc(M_WAITOK); 1334 getnewbufrestarts = counter_u64_alloc(M_WAITOK); 1335 mappingrestarts = counter_u64_alloc(M_WAITOK); 1336 numbufallocfails = counter_u64_alloc(M_WAITOK); 1337 notbufdflushes = counter_u64_alloc(M_WAITOK); 1338 buffreekvacnt = counter_u64_alloc(M_WAITOK); 1339 bufdefragcnt = counter_u64_alloc(M_WAITOK); 1340 bufkvaspace = counter_u64_alloc(M_WAITOK); 1341 TSEXIT(); 1342 } 1343 1344 #ifdef INVARIANTS 1345 static inline void 1346 vfs_buf_check_mapped(struct buf *bp) 1347 { 1348 1349 KASSERT(bp->b_kvabase != unmapped_buf, 1350 ("mapped buf: b_kvabase was not updated %p", bp)); 1351 KASSERT(bp->b_data != unmapped_buf, 1352 ("mapped buf: b_data was not updated %p", bp)); 1353 KASSERT(bp->b_data < unmapped_buf || bp->b_data >= unmapped_buf + 1354 maxphys, ("b_data + b_offset unmapped %p", bp)); 1355 } 1356 1357 static inline void 1358 vfs_buf_check_unmapped(struct buf *bp) 1359 { 1360 1361 KASSERT(bp->b_data == unmapped_buf, 1362 ("unmapped buf: corrupted b_data %p", bp)); 1363 } 1364 1365 #define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp) 1366 #define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp) 1367 #else 1368 #define BUF_CHECK_MAPPED(bp) do {} while (0) 1369 #define BUF_CHECK_UNMAPPED(bp) do {} while (0) 1370 #endif 1371 1372 static int 1373 isbufbusy(struct buf *bp) 1374 { 1375 if (((bp->b_flags & B_INVAL) == 0 && BUF_ISLOCKED(bp)) || 1376 ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)) 1377 return (1); 1378 return (0); 1379 } 1380 1381 /* 1382 * Shutdown the system cleanly to prepare for reboot, halt, or power off. 1383 */ 1384 void 1385 bufshutdown(int show_busybufs) 1386 { 1387 static int first_buf_printf = 1; 1388 struct buf *bp; 1389 int i, iter, nbusy, pbusy; 1390 #ifndef PREEMPTION 1391 int subiter; 1392 #endif 1393 1394 /* 1395 * Sync filesystems for shutdown 1396 */ 1397 wdog_kern_pat(WD_LASTVAL); 1398 kern_sync(curthread); 1399 1400 /* 1401 * With soft updates, some buffers that are 1402 * written will be remarked as dirty until other 1403 * buffers are written. 1404 */ 1405 for (iter = pbusy = 0; iter < 20; iter++) { 1406 nbusy = 0; 1407 for (i = nbuf - 1; i >= 0; i--) { 1408 bp = nbufp(i); 1409 if (isbufbusy(bp)) 1410 nbusy++; 1411 } 1412 if (nbusy == 0) { 1413 if (first_buf_printf) 1414 printf("All buffers synced."); 1415 break; 1416 } 1417 if (first_buf_printf) { 1418 printf("Syncing disks, buffers remaining... "); 1419 first_buf_printf = 0; 1420 } 1421 printf("%d ", nbusy); 1422 if (nbusy < pbusy) 1423 iter = 0; 1424 pbusy = nbusy; 1425 1426 wdog_kern_pat(WD_LASTVAL); 1427 kern_sync(curthread); 1428 1429 #ifdef PREEMPTION 1430 /* 1431 * Spin for a while to allow interrupt threads to run. 1432 */ 1433 DELAY(50000 * iter); 1434 #else 1435 /* 1436 * Context switch several times to allow interrupt 1437 * threads to run. 1438 */ 1439 for (subiter = 0; subiter < 50 * iter; subiter++) { 1440 sched_relinquish(curthread); 1441 DELAY(1000); 1442 } 1443 #endif 1444 } 1445 printf("\n"); 1446 /* 1447 * Count only busy local buffers to prevent forcing 1448 * a fsck if we're just a client of a wedged NFS server 1449 */ 1450 nbusy = 0; 1451 for (i = nbuf - 1; i >= 0; i--) { 1452 bp = nbufp(i); 1453 if (isbufbusy(bp)) { 1454 #if 0 1455 /* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */ 1456 if (bp->b_dev == NULL) { 1457 TAILQ_REMOVE(&mountlist, 1458 bp->b_vp->v_mount, mnt_list); 1459 continue; 1460 } 1461 #endif 1462 nbusy++; 1463 if (show_busybufs > 0) { 1464 printf( 1465 "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:", 1466 nbusy, bp, bp->b_vp, bp->b_flags, 1467 (intmax_t)bp->b_blkno, 1468 (intmax_t)bp->b_lblkno); 1469 BUF_LOCKPRINTINFO(bp); 1470 if (show_busybufs > 1) 1471 vn_printf(bp->b_vp, 1472 "vnode content: "); 1473 } 1474 } 1475 } 1476 if (nbusy) { 1477 /* 1478 * Failed to sync all blocks. Indicate this and don't 1479 * unmount filesystems (thus forcing an fsck on reboot). 1480 */ 1481 BOOTTRACE("shutdown failed to sync buffers"); 1482 printf("Giving up on %d buffers\n", nbusy); 1483 DELAY(5000000); /* 5 seconds */ 1484 swapoff_all(); 1485 } else { 1486 BOOTTRACE("shutdown sync complete"); 1487 if (!first_buf_printf) 1488 printf("Final sync complete\n"); 1489 1490 /* 1491 * Unmount filesystems and perform swapoff, to quiesce 1492 * the system as much as possible. In particular, no 1493 * I/O should be initiated from top levels since it 1494 * might be abruptly terminated by reset, or otherwise 1495 * erronously handled because other parts of the 1496 * system are disabled. 1497 * 1498 * Swapoff before unmount, because file-backed swap is 1499 * non-operational after unmount of the underlying 1500 * filesystem. 1501 */ 1502 if (!KERNEL_PANICKED()) { 1503 swapoff_all(); 1504 vfs_unmountall(); 1505 } 1506 BOOTTRACE("shutdown unmounted all filesystems"); 1507 } 1508 DELAY(100000); /* wait for console output to finish */ 1509 } 1510 1511 static void 1512 bpmap_qenter(struct buf *bp) 1513 { 1514 1515 BUF_CHECK_MAPPED(bp); 1516 1517 /* 1518 * bp->b_data is relative to bp->b_offset, but 1519 * bp->b_offset may be offset into the first page. 1520 */ 1521 bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data); 1522 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 1523 bp->b_data = (caddr_t)((vm_offset_t)bp->b_data | 1524 (vm_offset_t)(bp->b_offset & PAGE_MASK)); 1525 } 1526 1527 static inline struct bufdomain * 1528 bufdomain(struct buf *bp) 1529 { 1530 1531 return (&bdomain[bp->b_domain]); 1532 } 1533 1534 static struct bufqueue * 1535 bufqueue(struct buf *bp) 1536 { 1537 1538 switch (bp->b_qindex) { 1539 case QUEUE_NONE: 1540 /* FALLTHROUGH */ 1541 case QUEUE_SENTINEL: 1542 return (NULL); 1543 case QUEUE_EMPTY: 1544 return (&bqempty); 1545 case QUEUE_DIRTY: 1546 return (&bufdomain(bp)->bd_dirtyq); 1547 case QUEUE_CLEAN: 1548 return (&bufdomain(bp)->bd_subq[bp->b_subqueue]); 1549 default: 1550 break; 1551 } 1552 panic("bufqueue(%p): Unhandled type %d\n", bp, bp->b_qindex); 1553 } 1554 1555 /* 1556 * Return the locked bufqueue that bp is a member of. 1557 */ 1558 static struct bufqueue * 1559 bufqueue_acquire(struct buf *bp) 1560 { 1561 struct bufqueue *bq, *nbq; 1562 1563 /* 1564 * bp can be pushed from a per-cpu queue to the 1565 * cleanq while we're waiting on the lock. Retry 1566 * if the queues don't match. 1567 */ 1568 bq = bufqueue(bp); 1569 BQ_LOCK(bq); 1570 for (;;) { 1571 nbq = bufqueue(bp); 1572 if (bq == nbq) 1573 break; 1574 BQ_UNLOCK(bq); 1575 BQ_LOCK(nbq); 1576 bq = nbq; 1577 } 1578 return (bq); 1579 } 1580 1581 /* 1582 * binsfree: 1583 * 1584 * Insert the buffer into the appropriate free list. Requires a 1585 * locked buffer on entry and buffer is unlocked before return. 1586 */ 1587 static void 1588 binsfree(struct buf *bp, int qindex) 1589 { 1590 struct bufdomain *bd; 1591 struct bufqueue *bq; 1592 1593 KASSERT(qindex == QUEUE_CLEAN || qindex == QUEUE_DIRTY, 1594 ("binsfree: Invalid qindex %d", qindex)); 1595 BUF_ASSERT_XLOCKED(bp); 1596 1597 /* 1598 * Handle delayed bremfree() processing. 1599 */ 1600 if (bp->b_flags & B_REMFREE) { 1601 if (bp->b_qindex == qindex) { 1602 bp->b_flags |= B_REUSE; 1603 bp->b_flags &= ~B_REMFREE; 1604 BUF_UNLOCK(bp); 1605 return; 1606 } 1607 bq = bufqueue_acquire(bp); 1608 bq_remove(bq, bp); 1609 BQ_UNLOCK(bq); 1610 } 1611 bd = bufdomain(bp); 1612 if (qindex == QUEUE_CLEAN) { 1613 if (bd->bd_lim != 0) 1614 bq = &bd->bd_subq[PCPU_GET(cpuid)]; 1615 else 1616 bq = bd->bd_cleanq; 1617 } else 1618 bq = &bd->bd_dirtyq; 1619 bq_insert(bq, bp, true); 1620 } 1621 1622 /* 1623 * buf_free: 1624 * 1625 * Free a buffer to the buf zone once it no longer has valid contents. 1626 */ 1627 static void 1628 buf_free(struct buf *bp) 1629 { 1630 1631 if (bp->b_flags & B_REMFREE) 1632 bremfreef(bp); 1633 if (bp->b_vflags & BV_BKGRDINPROG) 1634 panic("losing buffer 1"); 1635 if (bp->b_rcred != NOCRED) { 1636 crfree(bp->b_rcred); 1637 bp->b_rcred = NOCRED; 1638 } 1639 if (bp->b_wcred != NOCRED) { 1640 crfree(bp->b_wcred); 1641 bp->b_wcred = NOCRED; 1642 } 1643 if (!LIST_EMPTY(&bp->b_dep)) 1644 buf_deallocate(bp); 1645 bufkva_free(bp); 1646 atomic_add_int(&bufdomain(bp)->bd_freebuffers, 1); 1647 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1648 BUF_UNLOCK(bp); 1649 uma_zfree(buf_zone, bp); 1650 } 1651 1652 /* 1653 * buf_import: 1654 * 1655 * Import bufs into the uma cache from the buf list. The system still 1656 * expects a static array of bufs and much of the synchronization 1657 * around bufs assumes type stable storage. As a result, UMA is used 1658 * only as a per-cpu cache of bufs still maintained on a global list. 1659 */ 1660 static int 1661 buf_import(void *arg, void **store, int cnt, int domain, int flags) 1662 { 1663 struct buf *bp; 1664 int i; 1665 1666 BQ_LOCK(&bqempty); 1667 for (i = 0; i < cnt; i++) { 1668 bp = TAILQ_FIRST(&bqempty.bq_queue); 1669 if (bp == NULL) 1670 break; 1671 bq_remove(&bqempty, bp); 1672 store[i] = bp; 1673 } 1674 BQ_UNLOCK(&bqempty); 1675 1676 return (i); 1677 } 1678 1679 /* 1680 * buf_release: 1681 * 1682 * Release bufs from the uma cache back to the buffer queues. 1683 */ 1684 static void 1685 buf_release(void *arg, void **store, int cnt) 1686 { 1687 struct bufqueue *bq; 1688 struct buf *bp; 1689 int i; 1690 1691 bq = &bqempty; 1692 BQ_LOCK(bq); 1693 for (i = 0; i < cnt; i++) { 1694 bp = store[i]; 1695 /* Inline bq_insert() to batch locking. */ 1696 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1697 bp->b_flags &= ~(B_AGE | B_REUSE); 1698 bq->bq_len++; 1699 bp->b_qindex = bq->bq_index; 1700 } 1701 BQ_UNLOCK(bq); 1702 } 1703 1704 /* 1705 * buf_alloc: 1706 * 1707 * Allocate an empty buffer header. 1708 */ 1709 static struct buf * 1710 buf_alloc(struct bufdomain *bd) 1711 { 1712 struct buf *bp; 1713 int freebufs, error; 1714 1715 /* 1716 * We can only run out of bufs in the buf zone if the average buf 1717 * is less than BKVASIZE. In this case the actual wait/block will 1718 * come from buf_reycle() failing to flush one of these small bufs. 1719 */ 1720 bp = NULL; 1721 freebufs = atomic_fetchadd_int(&bd->bd_freebuffers, -1); 1722 if (freebufs > 0) 1723 bp = uma_zalloc(buf_zone, M_NOWAIT); 1724 if (bp == NULL) { 1725 atomic_add_int(&bd->bd_freebuffers, 1); 1726 bufspace_daemon_wakeup(bd); 1727 counter_u64_add(numbufallocfails, 1); 1728 return (NULL); 1729 } 1730 /* 1731 * Wake-up the bufspace daemon on transition below threshold. 1732 */ 1733 if (freebufs == bd->bd_lofreebuffers) 1734 bufspace_daemon_wakeup(bd); 1735 1736 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL); 1737 KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, 1738 error)); 1739 (void)error; 1740 1741 KASSERT(bp->b_vp == NULL, 1742 ("bp: %p still has vnode %p.", bp, bp->b_vp)); 1743 KASSERT((bp->b_flags & (B_DELWRI | B_NOREUSE)) == 0, 1744 ("invalid buffer %p flags %#x", bp, bp->b_flags)); 1745 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0, 1746 ("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags)); 1747 KASSERT(bp->b_npages == 0, 1748 ("bp: %p still has %d vm pages\n", bp, bp->b_npages)); 1749 KASSERT(bp->b_kvasize == 0, ("bp: %p still has kva\n", bp)); 1750 KASSERT(bp->b_bufsize == 0, ("bp: %p still has bufspace\n", bp)); 1751 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1752 1753 bp->b_domain = BD_DOMAIN(bd); 1754 bp->b_flags = 0; 1755 bp->b_ioflags = 0; 1756 bp->b_xflags = 0; 1757 bp->b_vflags = 0; 1758 bp->b_vp = NULL; 1759 bp->b_blkno = bp->b_lblkno = 0; 1760 bp->b_offset = NOOFFSET; 1761 bp->b_iodone = 0; 1762 bp->b_error = 0; 1763 bp->b_resid = 0; 1764 bp->b_bcount = 0; 1765 bp->b_npages = 0; 1766 bp->b_dirtyoff = bp->b_dirtyend = 0; 1767 bp->b_bufobj = NULL; 1768 bp->b_data = bp->b_kvabase = unmapped_buf; 1769 bp->b_fsprivate1 = NULL; 1770 bp->b_fsprivate2 = NULL; 1771 bp->b_fsprivate3 = NULL; 1772 LIST_INIT(&bp->b_dep); 1773 1774 return (bp); 1775 } 1776 1777 /* 1778 * buf_recycle: 1779 * 1780 * Free a buffer from the given bufqueue. kva controls whether the 1781 * freed buf must own some kva resources. This is used for 1782 * defragmenting. 1783 */ 1784 static int 1785 buf_recycle(struct bufdomain *bd, bool kva) 1786 { 1787 struct bufqueue *bq; 1788 struct buf *bp, *nbp; 1789 1790 if (kva) 1791 counter_u64_add(bufdefragcnt, 1); 1792 nbp = NULL; 1793 bq = bd->bd_cleanq; 1794 BQ_LOCK(bq); 1795 KASSERT(BQ_LOCKPTR(bq) == BD_LOCKPTR(bd), 1796 ("buf_recycle: Locks don't match")); 1797 nbp = TAILQ_FIRST(&bq->bq_queue); 1798 1799 /* 1800 * Run scan, possibly freeing data and/or kva mappings on the fly 1801 * depending. 1802 */ 1803 while ((bp = nbp) != NULL) { 1804 /* 1805 * Calculate next bp (we can only use it if we do not 1806 * release the bqlock). 1807 */ 1808 nbp = TAILQ_NEXT(bp, b_freelist); 1809 1810 /* 1811 * If we are defragging then we need a buffer with 1812 * some kva to reclaim. 1813 */ 1814 if (kva && bp->b_kvasize == 0) 1815 continue; 1816 1817 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 1818 continue; 1819 1820 /* 1821 * Implement a second chance algorithm for frequently 1822 * accessed buffers. 1823 */ 1824 if ((bp->b_flags & B_REUSE) != 0) { 1825 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1826 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1827 bp->b_flags &= ~B_REUSE; 1828 BUF_UNLOCK(bp); 1829 continue; 1830 } 1831 1832 /* 1833 * Skip buffers with background writes in progress. 1834 */ 1835 if ((bp->b_vflags & BV_BKGRDINPROG) != 0) { 1836 BUF_UNLOCK(bp); 1837 continue; 1838 } 1839 1840 KASSERT(bp->b_qindex == QUEUE_CLEAN, 1841 ("buf_recycle: inconsistent queue %d bp %p", 1842 bp->b_qindex, bp)); 1843 KASSERT(bp->b_domain == BD_DOMAIN(bd), 1844 ("getnewbuf: queue domain %d doesn't match request %d", 1845 bp->b_domain, (int)BD_DOMAIN(bd))); 1846 /* 1847 * NOTE: nbp is now entirely invalid. We can only restart 1848 * the scan from this point on. 1849 */ 1850 bq_remove(bq, bp); 1851 BQ_UNLOCK(bq); 1852 1853 /* 1854 * Requeue the background write buffer with error and 1855 * restart the scan. 1856 */ 1857 if ((bp->b_vflags & BV_BKGRDERR) != 0) { 1858 bqrelse(bp); 1859 BQ_LOCK(bq); 1860 nbp = TAILQ_FIRST(&bq->bq_queue); 1861 continue; 1862 } 1863 bp->b_flags |= B_INVAL; 1864 brelse(bp); 1865 return (0); 1866 } 1867 bd->bd_wanted = 1; 1868 BQ_UNLOCK(bq); 1869 1870 return (ENOBUFS); 1871 } 1872 1873 /* 1874 * bremfree: 1875 * 1876 * Mark the buffer for removal from the appropriate free list. 1877 * 1878 */ 1879 void 1880 bremfree(struct buf *bp) 1881 { 1882 1883 CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1884 KASSERT((bp->b_flags & B_REMFREE) == 0, 1885 ("bremfree: buffer %p already marked for delayed removal.", bp)); 1886 KASSERT(bp->b_qindex != QUEUE_NONE, 1887 ("bremfree: buffer %p not on a queue.", bp)); 1888 BUF_ASSERT_XLOCKED(bp); 1889 1890 bp->b_flags |= B_REMFREE; 1891 } 1892 1893 /* 1894 * bremfreef: 1895 * 1896 * Force an immediate removal from a free list. Used only in nfs when 1897 * it abuses the b_freelist pointer. 1898 */ 1899 void 1900 bremfreef(struct buf *bp) 1901 { 1902 struct bufqueue *bq; 1903 1904 bq = bufqueue_acquire(bp); 1905 bq_remove(bq, bp); 1906 BQ_UNLOCK(bq); 1907 } 1908 1909 static void 1910 bq_init(struct bufqueue *bq, int qindex, int subqueue, const char *lockname) 1911 { 1912 1913 mtx_init(&bq->bq_lock, lockname, NULL, MTX_DEF); 1914 TAILQ_INIT(&bq->bq_queue); 1915 bq->bq_len = 0; 1916 bq->bq_index = qindex; 1917 bq->bq_subqueue = subqueue; 1918 } 1919 1920 static void 1921 bd_init(struct bufdomain *bd) 1922 { 1923 int i; 1924 1925 /* Per-CPU clean buf queues, plus one global queue. */ 1926 bd->bd_subq = mallocarray(mp_maxid + 2, sizeof(struct bufqueue), 1927 M_BIOBUF, M_WAITOK | M_ZERO); 1928 bd->bd_cleanq = &bd->bd_subq[mp_maxid + 1]; 1929 bq_init(bd->bd_cleanq, QUEUE_CLEAN, mp_maxid + 1, "bufq clean lock"); 1930 bq_init(&bd->bd_dirtyq, QUEUE_DIRTY, -1, "bufq dirty lock"); 1931 for (i = 0; i <= mp_maxid; i++) 1932 bq_init(&bd->bd_subq[i], QUEUE_CLEAN, i, 1933 "bufq clean subqueue lock"); 1934 mtx_init(&bd->bd_run_lock, "bufspace daemon run lock", NULL, MTX_DEF); 1935 } 1936 1937 /* 1938 * bq_remove: 1939 * 1940 * Removes a buffer from the free list, must be called with the 1941 * correct qlock held. 1942 */ 1943 static void 1944 bq_remove(struct bufqueue *bq, struct buf *bp) 1945 { 1946 1947 CTR3(KTR_BUF, "bq_remove(%p) vp %p flags %X", 1948 bp, bp->b_vp, bp->b_flags); 1949 KASSERT(bp->b_qindex != QUEUE_NONE, 1950 ("bq_remove: buffer %p not on a queue.", bp)); 1951 KASSERT(bufqueue(bp) == bq, 1952 ("bq_remove: Remove buffer %p from wrong queue.", bp)); 1953 1954 BQ_ASSERT_LOCKED(bq); 1955 if (bp->b_qindex != QUEUE_EMPTY) { 1956 BUF_ASSERT_XLOCKED(bp); 1957 } 1958 KASSERT(bq->bq_len >= 1, 1959 ("queue %d underflow", bp->b_qindex)); 1960 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1961 bq->bq_len--; 1962 bp->b_qindex = QUEUE_NONE; 1963 bp->b_flags &= ~(B_REMFREE | B_REUSE); 1964 } 1965 1966 static void 1967 bd_flush(struct bufdomain *bd, struct bufqueue *bq) 1968 { 1969 struct buf *bp; 1970 1971 BQ_ASSERT_LOCKED(bq); 1972 if (bq != bd->bd_cleanq) { 1973 BD_LOCK(bd); 1974 while ((bp = TAILQ_FIRST(&bq->bq_queue)) != NULL) { 1975 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1976 TAILQ_INSERT_TAIL(&bd->bd_cleanq->bq_queue, bp, 1977 b_freelist); 1978 bp->b_subqueue = bd->bd_cleanq->bq_subqueue; 1979 } 1980 bd->bd_cleanq->bq_len += bq->bq_len; 1981 bq->bq_len = 0; 1982 } 1983 if (bd->bd_wanted) { 1984 bd->bd_wanted = 0; 1985 wakeup(&bd->bd_wanted); 1986 } 1987 if (bq != bd->bd_cleanq) 1988 BD_UNLOCK(bd); 1989 } 1990 1991 static int 1992 bd_flushall(struct bufdomain *bd) 1993 { 1994 struct bufqueue *bq; 1995 int flushed; 1996 int i; 1997 1998 if (bd->bd_lim == 0) 1999 return (0); 2000 flushed = 0; 2001 for (i = 0; i <= mp_maxid; i++) { 2002 bq = &bd->bd_subq[i]; 2003 if (bq->bq_len == 0) 2004 continue; 2005 BQ_LOCK(bq); 2006 bd_flush(bd, bq); 2007 BQ_UNLOCK(bq); 2008 flushed++; 2009 } 2010 2011 return (flushed); 2012 } 2013 2014 static void 2015 bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock) 2016 { 2017 struct bufdomain *bd; 2018 2019 if (bp->b_qindex != QUEUE_NONE) 2020 panic("bq_insert: free buffer %p onto another queue?", bp); 2021 2022 bd = bufdomain(bp); 2023 if (bp->b_flags & B_AGE) { 2024 /* Place this buf directly on the real queue. */ 2025 if (bq->bq_index == QUEUE_CLEAN) 2026 bq = bd->bd_cleanq; 2027 BQ_LOCK(bq); 2028 TAILQ_INSERT_HEAD(&bq->bq_queue, bp, b_freelist); 2029 } else { 2030 BQ_LOCK(bq); 2031 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 2032 } 2033 bp->b_flags &= ~(B_AGE | B_REUSE); 2034 bq->bq_len++; 2035 bp->b_qindex = bq->bq_index; 2036 bp->b_subqueue = bq->bq_subqueue; 2037 2038 /* 2039 * Unlock before we notify so that we don't wakeup a waiter that 2040 * fails a trylock on the buf and sleeps again. 2041 */ 2042 if (unlock) 2043 BUF_UNLOCK(bp); 2044 2045 if (bp->b_qindex == QUEUE_CLEAN) { 2046 /* 2047 * Flush the per-cpu queue and notify any waiters. 2048 */ 2049 if (bd->bd_wanted || (bq != bd->bd_cleanq && 2050 bq->bq_len >= bd->bd_lim)) 2051 bd_flush(bd, bq); 2052 } 2053 BQ_UNLOCK(bq); 2054 } 2055 2056 /* 2057 * bufkva_free: 2058 * 2059 * Free the kva allocation for a buffer. 2060 * 2061 */ 2062 static void 2063 bufkva_free(struct buf *bp) 2064 { 2065 2066 #ifdef INVARIANTS 2067 if (bp->b_kvasize == 0) { 2068 KASSERT(bp->b_kvabase == unmapped_buf && 2069 bp->b_data == unmapped_buf, 2070 ("Leaked KVA space on %p", bp)); 2071 } else if (buf_mapped(bp)) 2072 BUF_CHECK_MAPPED(bp); 2073 else 2074 BUF_CHECK_UNMAPPED(bp); 2075 #endif 2076 if (bp->b_kvasize == 0) 2077 return; 2078 2079 vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, bp->b_kvasize); 2080 counter_u64_add(bufkvaspace, -bp->b_kvasize); 2081 counter_u64_add(buffreekvacnt, 1); 2082 bp->b_data = bp->b_kvabase = unmapped_buf; 2083 bp->b_kvasize = 0; 2084 } 2085 2086 /* 2087 * bufkva_alloc: 2088 * 2089 * Allocate the buffer KVA and set b_kvasize and b_kvabase. 2090 */ 2091 static int 2092 bufkva_alloc(struct buf *bp, int maxsize, int gbflags) 2093 { 2094 vm_offset_t addr; 2095 int error; 2096 2097 KASSERT((gbflags & GB_UNMAPPED) == 0 || (gbflags & GB_KVAALLOC) != 0, 2098 ("Invalid gbflags 0x%x in %s", gbflags, __func__)); 2099 MPASS((bp->b_flags & B_MAXPHYS) == 0); 2100 KASSERT(maxsize <= maxbcachebuf, 2101 ("bufkva_alloc kva too large %d %u", maxsize, maxbcachebuf)); 2102 2103 bufkva_free(bp); 2104 2105 addr = 0; 2106 error = vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr); 2107 if (error != 0) { 2108 /* 2109 * Buffer map is too fragmented. Request the caller 2110 * to defragment the map. 2111 */ 2112 return (error); 2113 } 2114 bp->b_kvabase = (caddr_t)addr; 2115 bp->b_kvasize = maxsize; 2116 counter_u64_add(bufkvaspace, bp->b_kvasize); 2117 if ((gbflags & GB_UNMAPPED) != 0) { 2118 bp->b_data = unmapped_buf; 2119 BUF_CHECK_UNMAPPED(bp); 2120 } else { 2121 bp->b_data = bp->b_kvabase; 2122 BUF_CHECK_MAPPED(bp); 2123 } 2124 return (0); 2125 } 2126 2127 /* 2128 * bufkva_reclaim: 2129 * 2130 * Reclaim buffer kva by freeing buffers holding kva. This is a vmem 2131 * callback that fires to avoid returning failure. 2132 */ 2133 static void 2134 bufkva_reclaim(vmem_t *vmem, int flags) 2135 { 2136 bool done; 2137 int q; 2138 int i; 2139 2140 done = false; 2141 for (i = 0; i < 5; i++) { 2142 for (q = 0; q < buf_domains; q++) 2143 if (buf_recycle(&bdomain[q], true) != 0) 2144 done = true; 2145 if (done) 2146 break; 2147 } 2148 return; 2149 } 2150 2151 /* 2152 * Attempt to initiate asynchronous I/O on read-ahead blocks. We must 2153 * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set, 2154 * the buffer is valid and we do not have to do anything. 2155 */ 2156 static void 2157 breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt, 2158 struct ucred * cred, int flags, void (*ckhashfunc)(struct buf *)) 2159 { 2160 struct buf *rabp; 2161 struct thread *td; 2162 int i; 2163 2164 td = curthread; 2165 2166 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 2167 if (inmem(vp, *rablkno)) 2168 continue; 2169 rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0); 2170 if ((rabp->b_flags & B_CACHE) != 0) { 2171 brelse(rabp); 2172 continue; 2173 } 2174 #ifdef RACCT 2175 if (racct_enable) { 2176 PROC_LOCK(curproc); 2177 racct_add_buf(curproc, rabp, 0); 2178 PROC_UNLOCK(curproc); 2179 } 2180 #endif /* RACCT */ 2181 td->td_ru.ru_inblock++; 2182 rabp->b_flags |= B_ASYNC; 2183 rabp->b_flags &= ~B_INVAL; 2184 if ((flags & GB_CKHASH) != 0) { 2185 rabp->b_flags |= B_CKHASH; 2186 rabp->b_ckhashcalc = ckhashfunc; 2187 } 2188 rabp->b_ioflags &= ~BIO_ERROR; 2189 rabp->b_iocmd = BIO_READ; 2190 if (rabp->b_rcred == NOCRED && cred != NOCRED) 2191 rabp->b_rcred = crhold(cred); 2192 vfs_busy_pages(rabp, 0); 2193 BUF_KERNPROC(rabp); 2194 rabp->b_iooffset = dbtob(rabp->b_blkno); 2195 bstrategy(rabp); 2196 } 2197 } 2198 2199 /* 2200 * Entry point for bread() and breadn() via #defines in sys/buf.h. 2201 * 2202 * Get a buffer with the specified data. Look in the cache first. We 2203 * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE 2204 * is set, the buffer is valid and we do not have to do anything, see 2205 * getblk(). Also starts asynchronous I/O on read-ahead blocks. 2206 * 2207 * Always return a NULL buffer pointer (in bpp) when returning an error. 2208 * 2209 * The blkno parameter is the logical block being requested. Normally 2210 * the mapping of logical block number to disk block address is done 2211 * by calling VOP_BMAP(). However, if the mapping is already known, the 2212 * disk block address can be passed using the dblkno parameter. If the 2213 * disk block address is not known, then the same value should be passed 2214 * for blkno and dblkno. 2215 */ 2216 int 2217 breadn_flags(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, 2218 daddr_t *rablkno, int *rabsize, int cnt, struct ucred *cred, int flags, 2219 void (*ckhashfunc)(struct buf *), struct buf **bpp) 2220 { 2221 struct buf *bp; 2222 struct thread *td; 2223 int error, readwait, rv; 2224 2225 CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size); 2226 td = curthread; 2227 /* 2228 * Can only return NULL if GB_LOCK_NOWAIT or GB_SPARSE flags 2229 * are specified. 2230 */ 2231 error = getblkx(vp, blkno, dblkno, size, 0, 0, flags, &bp); 2232 if (error != 0) { 2233 *bpp = NULL; 2234 return (error); 2235 } 2236 KASSERT(blkno == bp->b_lblkno, 2237 ("getblkx returned buffer for blkno %jd instead of blkno %jd", 2238 (intmax_t)bp->b_lblkno, (intmax_t)blkno)); 2239 flags &= ~GB_NOSPARSE; 2240 *bpp = bp; 2241 2242 /* 2243 * If not found in cache, do some I/O 2244 */ 2245 readwait = 0; 2246 if ((bp->b_flags & B_CACHE) == 0) { 2247 #ifdef RACCT 2248 if (racct_enable) { 2249 PROC_LOCK(td->td_proc); 2250 racct_add_buf(td->td_proc, bp, 0); 2251 PROC_UNLOCK(td->td_proc); 2252 } 2253 #endif /* RACCT */ 2254 td->td_ru.ru_inblock++; 2255 bp->b_iocmd = BIO_READ; 2256 bp->b_flags &= ~B_INVAL; 2257 if ((flags & GB_CKHASH) != 0) { 2258 bp->b_flags |= B_CKHASH; 2259 bp->b_ckhashcalc = ckhashfunc; 2260 } 2261 if ((flags & GB_CVTENXIO) != 0) 2262 bp->b_xflags |= BX_CVTENXIO; 2263 bp->b_ioflags &= ~BIO_ERROR; 2264 if (bp->b_rcred == NOCRED && cred != NOCRED) 2265 bp->b_rcred = crhold(cred); 2266 vfs_busy_pages(bp, 0); 2267 bp->b_iooffset = dbtob(bp->b_blkno); 2268 bstrategy(bp); 2269 ++readwait; 2270 } 2271 2272 /* 2273 * Attempt to initiate asynchronous I/O on read-ahead blocks. 2274 */ 2275 breada(vp, rablkno, rabsize, cnt, cred, flags, ckhashfunc); 2276 2277 rv = 0; 2278 if (readwait) { 2279 rv = bufwait(bp); 2280 if (rv != 0) { 2281 brelse(bp); 2282 *bpp = NULL; 2283 } 2284 } 2285 return (rv); 2286 } 2287 2288 /* 2289 * Write, release buffer on completion. (Done by iodone 2290 * if async). Do not bother writing anything if the buffer 2291 * is invalid. 2292 * 2293 * Note that we set B_CACHE here, indicating that buffer is 2294 * fully valid and thus cacheable. This is true even of NFS 2295 * now so we set it generally. This could be set either here 2296 * or in biodone() since the I/O is synchronous. We put it 2297 * here. 2298 */ 2299 int 2300 bufwrite(struct buf *bp) 2301 { 2302 int oldflags; 2303 struct vnode *vp; 2304 long space; 2305 int vp_md; 2306 2307 CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2308 if ((bp->b_bufobj->bo_flag & BO_DEAD) != 0) { 2309 bp->b_flags |= B_INVAL | B_RELBUF; 2310 bp->b_flags &= ~B_CACHE; 2311 brelse(bp); 2312 return (ENXIO); 2313 } 2314 if (bp->b_flags & B_INVAL) { 2315 brelse(bp); 2316 return (0); 2317 } 2318 2319 if (bp->b_flags & B_BARRIER) 2320 atomic_add_long(&barrierwrites, 1); 2321 2322 oldflags = bp->b_flags; 2323 2324 KASSERT(!(bp->b_vflags & BV_BKGRDINPROG), 2325 ("FFS background buffer should not get here %p", bp)); 2326 2327 vp = bp->b_vp; 2328 if (vp) 2329 vp_md = vp->v_vflag & VV_MD; 2330 else 2331 vp_md = 0; 2332 2333 /* 2334 * Mark the buffer clean. Increment the bufobj write count 2335 * before bundirty() call, to prevent other thread from seeing 2336 * empty dirty list and zero counter for writes in progress, 2337 * falsely indicating that the bufobj is clean. 2338 */ 2339 bufobj_wref(bp->b_bufobj); 2340 bundirty(bp); 2341 2342 bp->b_flags &= ~B_DONE; 2343 bp->b_ioflags &= ~BIO_ERROR; 2344 bp->b_flags |= B_CACHE; 2345 bp->b_iocmd = BIO_WRITE; 2346 2347 vfs_busy_pages(bp, 1); 2348 2349 /* 2350 * Normal bwrites pipeline writes 2351 */ 2352 bp->b_runningbufspace = bp->b_bufsize; 2353 space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace); 2354 2355 #ifdef RACCT 2356 if (racct_enable) { 2357 PROC_LOCK(curproc); 2358 racct_add_buf(curproc, bp, 1); 2359 PROC_UNLOCK(curproc); 2360 } 2361 #endif /* RACCT */ 2362 curthread->td_ru.ru_oublock++; 2363 if (oldflags & B_ASYNC) 2364 BUF_KERNPROC(bp); 2365 bp->b_iooffset = dbtob(bp->b_blkno); 2366 buf_track(bp, __func__); 2367 bstrategy(bp); 2368 2369 if ((oldflags & B_ASYNC) == 0) { 2370 int rtval = bufwait(bp); 2371 brelse(bp); 2372 return (rtval); 2373 } else if (space > hirunningspace) { 2374 /* 2375 * don't allow the async write to saturate the I/O 2376 * system. We will not deadlock here because 2377 * we are blocking waiting for I/O that is already in-progress 2378 * to complete. We do not block here if it is the update 2379 * or syncer daemon trying to clean up as that can lead 2380 * to deadlock. 2381 */ 2382 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md) 2383 waitrunningbufspace(); 2384 } 2385 2386 return (0); 2387 } 2388 2389 void 2390 bufbdflush(struct bufobj *bo, struct buf *bp) 2391 { 2392 struct buf *nbp; 2393 struct bufdomain *bd; 2394 2395 bd = &bdomain[bo->bo_domain]; 2396 if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh + 10) { 2397 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); 2398 altbufferflushes++; 2399 } else if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh) { 2400 BO_LOCK(bo); 2401 /* 2402 * Try to find a buffer to flush. 2403 */ 2404 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2405 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2406 BUF_LOCK(nbp, 2407 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2408 continue; 2409 if (bp == nbp) 2410 panic("bdwrite: found ourselves"); 2411 BO_UNLOCK(bo); 2412 /* Don't countdeps with the bo lock held. */ 2413 if (buf_countdeps(nbp, 0)) { 2414 BO_LOCK(bo); 2415 BUF_UNLOCK(nbp); 2416 continue; 2417 } 2418 if (nbp->b_flags & B_CLUSTEROK) { 2419 vfs_bio_awrite(nbp); 2420 } else { 2421 bremfree(nbp); 2422 bawrite(nbp); 2423 } 2424 dirtybufferflushes++; 2425 break; 2426 } 2427 if (nbp == NULL) 2428 BO_UNLOCK(bo); 2429 } 2430 } 2431 2432 /* 2433 * Delayed write. (Buffer is marked dirty). Do not bother writing 2434 * anything if the buffer is marked invalid. 2435 * 2436 * Note that since the buffer must be completely valid, we can safely 2437 * set B_CACHE. In fact, we have to set B_CACHE here rather then in 2438 * biodone() in order to prevent getblk from writing the buffer 2439 * out synchronously. 2440 */ 2441 void 2442 bdwrite(struct buf *bp) 2443 { 2444 struct thread *td = curthread; 2445 struct vnode *vp; 2446 struct bufobj *bo; 2447 2448 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2449 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2450 KASSERT((bp->b_flags & B_BARRIER) == 0, 2451 ("Barrier request in delayed write %p", bp)); 2452 2453 if (bp->b_flags & B_INVAL) { 2454 brelse(bp); 2455 return; 2456 } 2457 2458 /* 2459 * If we have too many dirty buffers, don't create any more. 2460 * If we are wildly over our limit, then force a complete 2461 * cleanup. Otherwise, just keep the situation from getting 2462 * out of control. Note that we have to avoid a recursive 2463 * disaster and not try to clean up after our own cleanup! 2464 */ 2465 vp = bp->b_vp; 2466 bo = bp->b_bufobj; 2467 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) { 2468 td->td_pflags |= TDP_INBDFLUSH; 2469 BO_BDFLUSH(bo, bp); 2470 td->td_pflags &= ~TDP_INBDFLUSH; 2471 } else 2472 recursiveflushes++; 2473 2474 bdirty(bp); 2475 /* 2476 * Set B_CACHE, indicating that the buffer is fully valid. This is 2477 * true even of NFS now. 2478 */ 2479 bp->b_flags |= B_CACHE; 2480 2481 /* 2482 * This bmap keeps the system from needing to do the bmap later, 2483 * perhaps when the system is attempting to do a sync. Since it 2484 * is likely that the indirect block -- or whatever other datastructure 2485 * that the filesystem needs is still in memory now, it is a good 2486 * thing to do this. Note also, that if the pageout daemon is 2487 * requesting a sync -- there might not be enough memory to do 2488 * the bmap then... So, this is important to do. 2489 */ 2490 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) { 2491 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 2492 } 2493 2494 buf_track(bp, __func__); 2495 2496 /* 2497 * Set the *dirty* buffer range based upon the VM system dirty 2498 * pages. 2499 * 2500 * Mark the buffer pages as clean. We need to do this here to 2501 * satisfy the vnode_pager and the pageout daemon, so that it 2502 * thinks that the pages have been "cleaned". Note that since 2503 * the pages are in a delayed write buffer -- the VFS layer 2504 * "will" see that the pages get written out on the next sync, 2505 * or perhaps the cluster will be completed. 2506 */ 2507 vfs_clean_pages_dirty_buf(bp); 2508 bqrelse(bp); 2509 2510 /* 2511 * note: we cannot initiate I/O from a bdwrite even if we wanted to, 2512 * due to the softdep code. 2513 */ 2514 } 2515 2516 /* 2517 * bdirty: 2518 * 2519 * Turn buffer into delayed write request. We must clear BIO_READ and 2520 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to 2521 * itself to properly update it in the dirty/clean lists. We mark it 2522 * B_DONE to ensure that any asynchronization of the buffer properly 2523 * clears B_DONE ( else a panic will occur later ). 2524 * 2525 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which 2526 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty() 2527 * should only be called if the buffer is known-good. 2528 * 2529 * Since the buffer is not on a queue, we do not update the numfreebuffers 2530 * count. 2531 * 2532 * The buffer must be on QUEUE_NONE. 2533 */ 2534 void 2535 bdirty(struct buf *bp) 2536 { 2537 2538 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X", 2539 bp, bp->b_vp, bp->b_flags); 2540 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2541 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2542 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2543 bp->b_flags &= ~(B_RELBUF); 2544 bp->b_iocmd = BIO_WRITE; 2545 2546 if ((bp->b_flags & B_DELWRI) == 0) { 2547 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI; 2548 reassignbuf(bp); 2549 bdirtyadd(bp); 2550 } 2551 } 2552 2553 /* 2554 * bundirty: 2555 * 2556 * Clear B_DELWRI for buffer. 2557 * 2558 * Since the buffer is not on a queue, we do not update the numfreebuffers 2559 * count. 2560 * 2561 * The buffer must be on QUEUE_NONE. 2562 */ 2563 2564 void 2565 bundirty(struct buf *bp) 2566 { 2567 2568 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2569 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2570 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2571 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2572 2573 if (bp->b_flags & B_DELWRI) { 2574 bp->b_flags &= ~B_DELWRI; 2575 reassignbuf(bp); 2576 bdirtysub(bp); 2577 } 2578 /* 2579 * Since it is now being written, we can clear its deferred write flag. 2580 */ 2581 bp->b_flags &= ~B_DEFERRED; 2582 } 2583 2584 /* 2585 * bawrite: 2586 * 2587 * Asynchronous write. Start output on a buffer, but do not wait for 2588 * it to complete. The buffer is released when the output completes. 2589 * 2590 * bwrite() ( or the VOP routine anyway ) is responsible for handling 2591 * B_INVAL buffers. Not us. 2592 */ 2593 void 2594 bawrite(struct buf *bp) 2595 { 2596 2597 bp->b_flags |= B_ASYNC; 2598 (void) bwrite(bp); 2599 } 2600 2601 /* 2602 * babarrierwrite: 2603 * 2604 * Asynchronous barrier write. Start output on a buffer, but do not 2605 * wait for it to complete. Place a write barrier after this write so 2606 * that this buffer and all buffers written before it are committed to 2607 * the disk before any buffers written after this write are committed 2608 * to the disk. The buffer is released when the output completes. 2609 */ 2610 void 2611 babarrierwrite(struct buf *bp) 2612 { 2613 2614 bp->b_flags |= B_ASYNC | B_BARRIER; 2615 (void) bwrite(bp); 2616 } 2617 2618 /* 2619 * bbarrierwrite: 2620 * 2621 * Synchronous barrier write. Start output on a buffer and wait for 2622 * it to complete. Place a write barrier after this write so that 2623 * this buffer and all buffers written before it are committed to 2624 * the disk before any buffers written after this write are committed 2625 * to the disk. The buffer is released when the output completes. 2626 */ 2627 int 2628 bbarrierwrite(struct buf *bp) 2629 { 2630 2631 bp->b_flags |= B_BARRIER; 2632 return (bwrite(bp)); 2633 } 2634 2635 /* 2636 * bwillwrite: 2637 * 2638 * Called prior to the locking of any vnodes when we are expecting to 2639 * write. We do not want to starve the buffer cache with too many 2640 * dirty buffers so we block here. By blocking prior to the locking 2641 * of any vnodes we attempt to avoid the situation where a locked vnode 2642 * prevents the various system daemons from flushing related buffers. 2643 */ 2644 void 2645 bwillwrite(void) 2646 { 2647 2648 if (buf_dirty_count_severe()) { 2649 mtx_lock(&bdirtylock); 2650 while (buf_dirty_count_severe()) { 2651 bdirtywait = 1; 2652 msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4), 2653 "flswai", 0); 2654 } 2655 mtx_unlock(&bdirtylock); 2656 } 2657 } 2658 2659 /* 2660 * Return true if we have too many dirty buffers. 2661 */ 2662 int 2663 buf_dirty_count_severe(void) 2664 { 2665 2666 return (!BIT_EMPTY(BUF_DOMAINS, &bdhidirty)); 2667 } 2668 2669 /* 2670 * brelse: 2671 * 2672 * Release a busy buffer and, if requested, free its resources. The 2673 * buffer will be stashed in the appropriate bufqueue[] allowing it 2674 * to be accessed later as a cache entity or reused for other purposes. 2675 */ 2676 void 2677 brelse(struct buf *bp) 2678 { 2679 struct mount *v_mnt; 2680 int qindex; 2681 2682 /* 2683 * Many functions erroneously call brelse with a NULL bp under rare 2684 * error conditions. Simply return when called with a NULL bp. 2685 */ 2686 if (bp == NULL) 2687 return; 2688 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X", 2689 bp, bp->b_vp, bp->b_flags); 2690 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2691 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2692 KASSERT((bp->b_flags & B_VMIO) != 0 || (bp->b_flags & B_NOREUSE) == 0, 2693 ("brelse: non-VMIO buffer marked NOREUSE")); 2694 2695 if (BUF_LOCKRECURSED(bp)) { 2696 /* 2697 * Do not process, in particular, do not handle the 2698 * B_INVAL/B_RELBUF and do not release to free list. 2699 */ 2700 BUF_UNLOCK(bp); 2701 return; 2702 } 2703 2704 if (bp->b_flags & B_MANAGED) { 2705 bqrelse(bp); 2706 return; 2707 } 2708 2709 if (LIST_EMPTY(&bp->b_dep)) { 2710 bp->b_flags &= ~B_IOSTARTED; 2711 } else { 2712 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2713 ("brelse: SU io not finished bp %p", bp)); 2714 } 2715 2716 if ((bp->b_vflags & (BV_BKGRDINPROG | BV_BKGRDERR)) == BV_BKGRDERR) { 2717 BO_LOCK(bp->b_bufobj); 2718 bp->b_vflags &= ~BV_BKGRDERR; 2719 BO_UNLOCK(bp->b_bufobj); 2720 bdirty(bp); 2721 } 2722 2723 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2724 (bp->b_flags & B_INVALONERR)) { 2725 /* 2726 * Forced invalidation of dirty buffer contents, to be used 2727 * after a failed write in the rare case that the loss of the 2728 * contents is acceptable. The buffer is invalidated and 2729 * freed. 2730 */ 2731 bp->b_flags |= B_INVAL | B_RELBUF | B_NOCACHE; 2732 bp->b_flags &= ~(B_ASYNC | B_CACHE); 2733 } 2734 2735 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2736 (bp->b_error != ENXIO || !LIST_EMPTY(&bp->b_dep)) && 2737 !(bp->b_flags & B_INVAL)) { 2738 /* 2739 * Failed write, redirty. All errors except ENXIO (which 2740 * means the device is gone) are treated as being 2741 * transient. 2742 * 2743 * XXX Treating EIO as transient is not correct; the 2744 * contract with the local storage device drivers is that 2745 * they will only return EIO once the I/O is no longer 2746 * retriable. Network I/O also respects this through the 2747 * guarantees of TCP and/or the internal retries of NFS. 2748 * ENOMEM might be transient, but we also have no way of 2749 * knowing when its ok to retry/reschedule. In general, 2750 * this entire case should be made obsolete through better 2751 * error handling/recovery and resource scheduling. 2752 * 2753 * Do this also for buffers that failed with ENXIO, but have 2754 * non-empty dependencies - the soft updates code might need 2755 * to access the buffer to untangle them. 2756 * 2757 * Must clear BIO_ERROR to prevent pages from being scrapped. 2758 */ 2759 bp->b_ioflags &= ~BIO_ERROR; 2760 bdirty(bp); 2761 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) || 2762 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) { 2763 /* 2764 * Either a failed read I/O, or we were asked to free or not 2765 * cache the buffer, or we failed to write to a device that's 2766 * no longer present. 2767 */ 2768 bp->b_flags |= B_INVAL; 2769 if (!LIST_EMPTY(&bp->b_dep)) 2770 buf_deallocate(bp); 2771 if (bp->b_flags & B_DELWRI) 2772 bdirtysub(bp); 2773 bp->b_flags &= ~(B_DELWRI | B_CACHE); 2774 if ((bp->b_flags & B_VMIO) == 0) { 2775 allocbuf(bp, 0); 2776 if (bp->b_vp) 2777 brelvp(bp); 2778 } 2779 } 2780 2781 /* 2782 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_truncate() 2783 * is called with B_DELWRI set, the underlying pages may wind up 2784 * getting freed causing a previous write (bdwrite()) to get 'lost' 2785 * because pages associated with a B_DELWRI bp are marked clean. 2786 * 2787 * We still allow the B_INVAL case to call vfs_vmio_truncate(), even 2788 * if B_DELWRI is set. 2789 */ 2790 if (bp->b_flags & B_DELWRI) 2791 bp->b_flags &= ~B_RELBUF; 2792 2793 /* 2794 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 2795 * constituted, not even NFS buffers now. Two flags effect this. If 2796 * B_INVAL, the struct buf is invalidated but the VM object is kept 2797 * around ( i.e. so it is trivial to reconstitute the buffer later ). 2798 * 2799 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be 2800 * invalidated. BIO_ERROR cannot be set for a failed write unless the 2801 * buffer is also B_INVAL because it hits the re-dirtying code above. 2802 * 2803 * Normally we can do this whether a buffer is B_DELWRI or not. If 2804 * the buffer is an NFS buffer, it is tracking piecemeal writes or 2805 * the commit state and we cannot afford to lose the buffer. If the 2806 * buffer has a background write in progress, we need to keep it 2807 * around to prevent it from being reconstituted and starting a second 2808 * background write. 2809 */ 2810 2811 v_mnt = bp->b_vp != NULL ? bp->b_vp->v_mount : NULL; 2812 2813 if ((bp->b_flags & B_VMIO) && (bp->b_flags & B_NOCACHE || 2814 (bp->b_ioflags & BIO_ERROR && bp->b_iocmd == BIO_READ)) && 2815 (v_mnt == NULL || (v_mnt->mnt_vfc->vfc_flags & VFCF_NETWORK) == 0 || 2816 vn_isdisk(bp->b_vp) || (bp->b_flags & B_DELWRI) == 0)) { 2817 vfs_vmio_invalidate(bp); 2818 allocbuf(bp, 0); 2819 } 2820 2821 if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0 || 2822 (bp->b_flags & (B_DELWRI | B_NOREUSE)) == B_NOREUSE) { 2823 allocbuf(bp, 0); 2824 bp->b_flags &= ~B_NOREUSE; 2825 if (bp->b_vp != NULL) 2826 brelvp(bp); 2827 } 2828 2829 /* 2830 * If the buffer has junk contents signal it and eventually 2831 * clean up B_DELWRI and diassociate the vnode so that gbincore() 2832 * doesn't find it. 2833 */ 2834 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 || 2835 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0) 2836 bp->b_flags |= B_INVAL; 2837 if (bp->b_flags & B_INVAL) { 2838 if (bp->b_flags & B_DELWRI) 2839 bundirty(bp); 2840 if (bp->b_vp) 2841 brelvp(bp); 2842 } 2843 2844 buf_track(bp, __func__); 2845 2846 /* buffers with no memory */ 2847 if (bp->b_bufsize == 0) { 2848 buf_free(bp); 2849 return; 2850 } 2851 /* buffers with junk contents */ 2852 if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) || 2853 (bp->b_ioflags & BIO_ERROR)) { 2854 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 2855 if (bp->b_vflags & BV_BKGRDINPROG) 2856 panic("losing buffer 2"); 2857 qindex = QUEUE_CLEAN; 2858 bp->b_flags |= B_AGE; 2859 /* remaining buffers */ 2860 } else if (bp->b_flags & B_DELWRI) 2861 qindex = QUEUE_DIRTY; 2862 else 2863 qindex = QUEUE_CLEAN; 2864 2865 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) 2866 panic("brelse: not dirty"); 2867 2868 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_RELBUF | B_DIRECT); 2869 bp->b_xflags &= ~(BX_CVTENXIO); 2870 /* binsfree unlocks bp. */ 2871 binsfree(bp, qindex); 2872 } 2873 2874 /* 2875 * Release a buffer back to the appropriate queue but do not try to free 2876 * it. The buffer is expected to be used again soon. 2877 * 2878 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by 2879 * biodone() to requeue an async I/O on completion. It is also used when 2880 * known good buffers need to be requeued but we think we may need the data 2881 * again soon. 2882 * 2883 * XXX we should be able to leave the B_RELBUF hint set on completion. 2884 */ 2885 void 2886 bqrelse(struct buf *bp) 2887 { 2888 int qindex; 2889 2890 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2891 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2892 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2893 2894 qindex = QUEUE_NONE; 2895 if (BUF_LOCKRECURSED(bp)) { 2896 /* do not release to free list */ 2897 BUF_UNLOCK(bp); 2898 return; 2899 } 2900 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 2901 bp->b_xflags &= ~(BX_CVTENXIO); 2902 2903 if (LIST_EMPTY(&bp->b_dep)) { 2904 bp->b_flags &= ~B_IOSTARTED; 2905 } else { 2906 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2907 ("bqrelse: SU io not finished bp %p", bp)); 2908 } 2909 2910 if (bp->b_flags & B_MANAGED) { 2911 if (bp->b_flags & B_REMFREE) 2912 bremfreef(bp); 2913 goto out; 2914 } 2915 2916 /* buffers with stale but valid contents */ 2917 if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG | 2918 BV_BKGRDERR)) == BV_BKGRDERR) { 2919 BO_LOCK(bp->b_bufobj); 2920 bp->b_vflags &= ~BV_BKGRDERR; 2921 BO_UNLOCK(bp->b_bufobj); 2922 qindex = QUEUE_DIRTY; 2923 } else { 2924 if ((bp->b_flags & B_DELWRI) == 0 && 2925 (bp->b_xflags & BX_VNDIRTY)) 2926 panic("bqrelse: not dirty"); 2927 if ((bp->b_flags & B_NOREUSE) != 0) { 2928 brelse(bp); 2929 return; 2930 } 2931 qindex = QUEUE_CLEAN; 2932 } 2933 buf_track(bp, __func__); 2934 /* binsfree unlocks bp. */ 2935 binsfree(bp, qindex); 2936 return; 2937 2938 out: 2939 buf_track(bp, __func__); 2940 /* unlock */ 2941 BUF_UNLOCK(bp); 2942 } 2943 2944 /* 2945 * Complete I/O to a VMIO backed page. Validate the pages as appropriate, 2946 * restore bogus pages. 2947 */ 2948 static void 2949 vfs_vmio_iodone(struct buf *bp) 2950 { 2951 vm_ooffset_t foff; 2952 vm_page_t m; 2953 vm_object_t obj; 2954 struct vnode *vp __unused; 2955 int i, iosize, resid; 2956 bool bogus; 2957 2958 obj = bp->b_bufobj->bo_object; 2959 KASSERT(blockcount_read(&obj->paging_in_progress) >= bp->b_npages, 2960 ("vfs_vmio_iodone: paging in progress(%d) < b_npages(%d)", 2961 blockcount_read(&obj->paging_in_progress), bp->b_npages)); 2962 2963 vp = bp->b_vp; 2964 VNPASS(vp->v_holdcnt > 0, vp); 2965 VNPASS(vp->v_object != NULL, vp); 2966 2967 foff = bp->b_offset; 2968 KASSERT(bp->b_offset != NOOFFSET, 2969 ("vfs_vmio_iodone: bp %p has no buffer offset", bp)); 2970 2971 bogus = false; 2972 iosize = bp->b_bcount - bp->b_resid; 2973 for (i = 0; i < bp->b_npages; i++) { 2974 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff; 2975 if (resid > iosize) 2976 resid = iosize; 2977 2978 /* 2979 * cleanup bogus pages, restoring the originals 2980 */ 2981 m = bp->b_pages[i]; 2982 if (m == bogus_page) { 2983 bogus = true; 2984 m = vm_page_relookup(obj, OFF_TO_IDX(foff)); 2985 if (m == NULL) 2986 panic("biodone: page disappeared!"); 2987 bp->b_pages[i] = m; 2988 } else if ((bp->b_iocmd == BIO_READ) && resid > 0) { 2989 /* 2990 * In the write case, the valid and clean bits are 2991 * already changed correctly ( see bdwrite() ), so we 2992 * only need to do this here in the read case. 2993 */ 2994 KASSERT((m->dirty & vm_page_bits(foff & PAGE_MASK, 2995 resid)) == 0, ("vfs_vmio_iodone: page %p " 2996 "has unexpected dirty bits", m)); 2997 vfs_page_set_valid(bp, foff, m); 2998 } 2999 KASSERT(OFF_TO_IDX(foff) == m->pindex, 3000 ("vfs_vmio_iodone: foff(%jd)/pindex(%ju) mismatch", 3001 (intmax_t)foff, (uintmax_t)m->pindex)); 3002 3003 vm_page_sunbusy(m); 3004 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3005 iosize -= resid; 3006 } 3007 vm_object_pip_wakeupn(obj, bp->b_npages); 3008 if (bogus && buf_mapped(bp)) { 3009 BUF_CHECK_MAPPED(bp); 3010 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 3011 bp->b_pages, bp->b_npages); 3012 } 3013 } 3014 3015 /* 3016 * Perform page invalidation when a buffer is released. The fully invalid 3017 * pages will be reclaimed later in vfs_vmio_truncate(). 3018 */ 3019 static void 3020 vfs_vmio_invalidate(struct buf *bp) 3021 { 3022 vm_object_t obj; 3023 vm_page_t m; 3024 int flags, i, resid, poffset, presid; 3025 3026 if (buf_mapped(bp)) { 3027 BUF_CHECK_MAPPED(bp); 3028 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages); 3029 } else 3030 BUF_CHECK_UNMAPPED(bp); 3031 /* 3032 * Get the base offset and length of the buffer. Note that 3033 * in the VMIO case if the buffer block size is not 3034 * page-aligned then b_data pointer may not be page-aligned. 3035 * But our b_pages[] array *IS* page aligned. 3036 * 3037 * block sizes less then DEV_BSIZE (usually 512) are not 3038 * supported due to the page granularity bits (m->valid, 3039 * m->dirty, etc...). 3040 * 3041 * See man buf(9) for more information 3042 */ 3043 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3044 obj = bp->b_bufobj->bo_object; 3045 resid = bp->b_bufsize; 3046 poffset = bp->b_offset & PAGE_MASK; 3047 VM_OBJECT_WLOCK(obj); 3048 for (i = 0; i < bp->b_npages; i++) { 3049 m = bp->b_pages[i]; 3050 if (m == bogus_page) 3051 panic("vfs_vmio_invalidate: Unexpected bogus page."); 3052 bp->b_pages[i] = NULL; 3053 3054 presid = resid > (PAGE_SIZE - poffset) ? 3055 (PAGE_SIZE - poffset) : resid; 3056 KASSERT(presid >= 0, ("brelse: extra page")); 3057 vm_page_busy_acquire(m, VM_ALLOC_SBUSY); 3058 if (pmap_page_wired_mappings(m) == 0) 3059 vm_page_set_invalid(m, poffset, presid); 3060 vm_page_sunbusy(m); 3061 vm_page_release_locked(m, flags); 3062 resid -= presid; 3063 poffset = 0; 3064 } 3065 VM_OBJECT_WUNLOCK(obj); 3066 bp->b_npages = 0; 3067 } 3068 3069 /* 3070 * Page-granular truncation of an existing VMIO buffer. 3071 */ 3072 static void 3073 vfs_vmio_truncate(struct buf *bp, int desiredpages) 3074 { 3075 vm_object_t obj; 3076 vm_page_t m; 3077 int flags, i; 3078 3079 if (bp->b_npages == desiredpages) 3080 return; 3081 3082 if (buf_mapped(bp)) { 3083 BUF_CHECK_MAPPED(bp); 3084 pmap_qremove((vm_offset_t)trunc_page((vm_offset_t)bp->b_data) + 3085 (desiredpages << PAGE_SHIFT), bp->b_npages - desiredpages); 3086 } else 3087 BUF_CHECK_UNMAPPED(bp); 3088 3089 /* 3090 * The object lock is needed only if we will attempt to free pages. 3091 */ 3092 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3093 if ((bp->b_flags & B_DIRECT) != 0) { 3094 flags |= VPR_TRYFREE; 3095 obj = bp->b_bufobj->bo_object; 3096 VM_OBJECT_WLOCK(obj); 3097 } else { 3098 obj = NULL; 3099 } 3100 for (i = desiredpages; i < bp->b_npages; i++) { 3101 m = bp->b_pages[i]; 3102 KASSERT(m != bogus_page, ("allocbuf: bogus page found")); 3103 bp->b_pages[i] = NULL; 3104 if (obj != NULL) 3105 vm_page_release_locked(m, flags); 3106 else 3107 vm_page_release(m, flags); 3108 } 3109 if (obj != NULL) 3110 VM_OBJECT_WUNLOCK(obj); 3111 bp->b_npages = desiredpages; 3112 } 3113 3114 /* 3115 * Byte granular extension of VMIO buffers. 3116 */ 3117 static void 3118 vfs_vmio_extend(struct buf *bp, int desiredpages, int size) 3119 { 3120 /* 3121 * We are growing the buffer, possibly in a 3122 * byte-granular fashion. 3123 */ 3124 vm_object_t obj; 3125 vm_offset_t toff; 3126 vm_offset_t tinc; 3127 vm_page_t m; 3128 3129 /* 3130 * Step 1, bring in the VM pages from the object, allocating 3131 * them if necessary. We must clear B_CACHE if these pages 3132 * are not valid for the range covered by the buffer. 3133 */ 3134 obj = bp->b_bufobj->bo_object; 3135 if (bp->b_npages < desiredpages) { 3136 KASSERT(desiredpages <= atop(maxbcachebuf), 3137 ("vfs_vmio_extend past maxbcachebuf %p %d %u", 3138 bp, desiredpages, maxbcachebuf)); 3139 3140 /* 3141 * We must allocate system pages since blocking 3142 * here could interfere with paging I/O, no 3143 * matter which process we are. 3144 * 3145 * Only exclusive busy can be tested here. 3146 * Blocking on shared busy might lead to 3147 * deadlocks once allocbuf() is called after 3148 * pages are vfs_busy_pages(). 3149 */ 3150 (void)vm_page_grab_pages_unlocked(obj, 3151 OFF_TO_IDX(bp->b_offset) + bp->b_npages, 3152 VM_ALLOC_SYSTEM | VM_ALLOC_IGN_SBUSY | 3153 VM_ALLOC_NOBUSY | VM_ALLOC_WIRED, 3154 &bp->b_pages[bp->b_npages], desiredpages - bp->b_npages); 3155 bp->b_npages = desiredpages; 3156 } 3157 3158 /* 3159 * Step 2. We've loaded the pages into the buffer, 3160 * we have to figure out if we can still have B_CACHE 3161 * set. Note that B_CACHE is set according to the 3162 * byte-granular range ( bcount and size ), not the 3163 * aligned range ( newbsize ). 3164 * 3165 * The VM test is against m->valid, which is DEV_BSIZE 3166 * aligned. Needless to say, the validity of the data 3167 * needs to also be DEV_BSIZE aligned. Note that this 3168 * fails with NFS if the server or some other client 3169 * extends the file's EOF. If our buffer is resized, 3170 * B_CACHE may remain set! XXX 3171 */ 3172 toff = bp->b_bcount; 3173 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK); 3174 while ((bp->b_flags & B_CACHE) && toff < size) { 3175 vm_pindex_t pi; 3176 3177 if (tinc > (size - toff)) 3178 tinc = size - toff; 3179 pi = ((bp->b_offset & PAGE_MASK) + toff) >> PAGE_SHIFT; 3180 m = bp->b_pages[pi]; 3181 vfs_buf_test_cache(bp, bp->b_offset, toff, tinc, m); 3182 toff += tinc; 3183 tinc = PAGE_SIZE; 3184 } 3185 3186 /* 3187 * Step 3, fixup the KVA pmap. 3188 */ 3189 if (buf_mapped(bp)) 3190 bpmap_qenter(bp); 3191 else 3192 BUF_CHECK_UNMAPPED(bp); 3193 } 3194 3195 /* 3196 * Check to see if a block at a particular lbn is available for a clustered 3197 * write. 3198 */ 3199 static int 3200 vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno) 3201 { 3202 struct buf *bpa; 3203 int match; 3204 3205 match = 0; 3206 3207 /* If the buf isn't in core skip it */ 3208 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL) 3209 return (0); 3210 3211 /* If the buf is busy we don't want to wait for it */ 3212 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 3213 return (0); 3214 3215 /* Only cluster with valid clusterable delayed write buffers */ 3216 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) != 3217 (B_DELWRI | B_CLUSTEROK)) 3218 goto done; 3219 3220 if (bpa->b_bufsize != size) 3221 goto done; 3222 3223 /* 3224 * Check to see if it is in the expected place on disk and that the 3225 * block has been mapped. 3226 */ 3227 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno)) 3228 match = 1; 3229 done: 3230 BUF_UNLOCK(bpa); 3231 return (match); 3232 } 3233 3234 /* 3235 * vfs_bio_awrite: 3236 * 3237 * Implement clustered async writes for clearing out B_DELWRI buffers. 3238 * This is much better then the old way of writing only one buffer at 3239 * a time. Note that we may not be presented with the buffers in the 3240 * correct order, so we search for the cluster in both directions. 3241 */ 3242 int 3243 vfs_bio_awrite(struct buf *bp) 3244 { 3245 struct bufobj *bo; 3246 int i; 3247 int j; 3248 daddr_t lblkno = bp->b_lblkno; 3249 struct vnode *vp = bp->b_vp; 3250 int ncl; 3251 int nwritten; 3252 int size; 3253 int maxcl; 3254 int gbflags; 3255 3256 bo = &vp->v_bufobj; 3257 gbflags = (bp->b_data == unmapped_buf) ? GB_UNMAPPED : 0; 3258 /* 3259 * right now we support clustered writing only to regular files. If 3260 * we find a clusterable block we could be in the middle of a cluster 3261 * rather then at the beginning. 3262 */ 3263 if ((vp->v_type == VREG) && 3264 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 3265 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 3266 size = vp->v_mount->mnt_stat.f_iosize; 3267 maxcl = maxphys / size; 3268 3269 BO_RLOCK(bo); 3270 for (i = 1; i < maxcl; i++) 3271 if (vfs_bio_clcheck(vp, size, lblkno + i, 3272 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0) 3273 break; 3274 3275 for (j = 1; i + j <= maxcl && j <= lblkno; j++) 3276 if (vfs_bio_clcheck(vp, size, lblkno - j, 3277 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0) 3278 break; 3279 BO_RUNLOCK(bo); 3280 --j; 3281 ncl = i + j; 3282 /* 3283 * this is a possible cluster write 3284 */ 3285 if (ncl != 1) { 3286 BUF_UNLOCK(bp); 3287 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, 3288 gbflags); 3289 return (nwritten); 3290 } 3291 } 3292 bremfree(bp); 3293 bp->b_flags |= B_ASYNC; 3294 /* 3295 * default (old) behavior, writing out only one block 3296 * 3297 * XXX returns b_bufsize instead of b_bcount for nwritten? 3298 */ 3299 nwritten = bp->b_bufsize; 3300 (void) bwrite(bp); 3301 3302 return (nwritten); 3303 } 3304 3305 /* 3306 * getnewbuf_kva: 3307 * 3308 * Allocate KVA for an empty buf header according to gbflags. 3309 */ 3310 static int 3311 getnewbuf_kva(struct buf *bp, int gbflags, int maxsize) 3312 { 3313 3314 if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_UNMAPPED) { 3315 /* 3316 * In order to keep fragmentation sane we only allocate kva 3317 * in BKVASIZE chunks. XXX with vmem we can do page size. 3318 */ 3319 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK; 3320 3321 if (maxsize != bp->b_kvasize && 3322 bufkva_alloc(bp, maxsize, gbflags)) 3323 return (ENOSPC); 3324 } 3325 return (0); 3326 } 3327 3328 /* 3329 * getnewbuf: 3330 * 3331 * Find and initialize a new buffer header, freeing up existing buffers 3332 * in the bufqueues as necessary. The new buffer is returned locked. 3333 * 3334 * We block if: 3335 * We have insufficient buffer headers 3336 * We have insufficient buffer space 3337 * buffer_arena is too fragmented ( space reservation fails ) 3338 * If we have to flush dirty buffers ( but we try to avoid this ) 3339 * 3340 * The caller is responsible for releasing the reserved bufspace after 3341 * allocbuf() is called. 3342 */ 3343 static struct buf * 3344 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int maxsize, int gbflags) 3345 { 3346 struct bufdomain *bd; 3347 struct buf *bp; 3348 bool metadata, reserved; 3349 3350 bp = NULL; 3351 KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3352 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3353 if (!unmapped_buf_allowed) 3354 gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3355 3356 if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 || 3357 vp->v_type == VCHR) 3358 metadata = true; 3359 else 3360 metadata = false; 3361 if (vp == NULL) 3362 bd = &bdomain[0]; 3363 else 3364 bd = &bdomain[vp->v_bufobj.bo_domain]; 3365 3366 counter_u64_add(getnewbufcalls, 1); 3367 reserved = false; 3368 do { 3369 if (reserved == false && 3370 bufspace_reserve(bd, maxsize, metadata) != 0) { 3371 counter_u64_add(getnewbufrestarts, 1); 3372 continue; 3373 } 3374 reserved = true; 3375 if ((bp = buf_alloc(bd)) == NULL) { 3376 counter_u64_add(getnewbufrestarts, 1); 3377 continue; 3378 } 3379 if (getnewbuf_kva(bp, gbflags, maxsize) == 0) 3380 return (bp); 3381 break; 3382 } while (buf_recycle(bd, false) == 0); 3383 3384 if (reserved) 3385 bufspace_release(bd, maxsize); 3386 if (bp != NULL) { 3387 bp->b_flags |= B_INVAL; 3388 brelse(bp); 3389 } 3390 bufspace_wait(bd, vp, gbflags, slpflag, slptimeo); 3391 3392 return (NULL); 3393 } 3394 3395 /* 3396 * buf_daemon: 3397 * 3398 * buffer flushing daemon. Buffers are normally flushed by the 3399 * update daemon but if it cannot keep up this process starts to 3400 * take the load in an attempt to prevent getnewbuf() from blocking. 3401 */ 3402 static struct kproc_desc buf_kp = { 3403 "bufdaemon", 3404 buf_daemon, 3405 &bufdaemonproc 3406 }; 3407 SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp); 3408 3409 static int 3410 buf_flush(struct vnode *vp, struct bufdomain *bd, int target) 3411 { 3412 int flushed; 3413 3414 flushed = flushbufqueues(vp, bd, target, 0); 3415 if (flushed == 0) { 3416 /* 3417 * Could not find any buffers without rollback 3418 * dependencies, so just write the first one 3419 * in the hopes of eventually making progress. 3420 */ 3421 if (vp != NULL && target > 2) 3422 target /= 2; 3423 flushbufqueues(vp, bd, target, 1); 3424 } 3425 return (flushed); 3426 } 3427 3428 static void 3429 buf_daemon_shutdown(void *arg __unused, int howto __unused) 3430 { 3431 int error; 3432 3433 if (KERNEL_PANICKED()) 3434 return; 3435 3436 mtx_lock(&bdlock); 3437 bd_shutdown = true; 3438 wakeup(&bd_request); 3439 error = msleep(&bd_shutdown, &bdlock, 0, "buf_daemon_shutdown", 3440 60 * hz); 3441 mtx_unlock(&bdlock); 3442 if (error != 0) 3443 printf("bufdaemon wait error: %d\n", error); 3444 } 3445 3446 static void 3447 buf_daemon(void) 3448 { 3449 struct bufdomain *bd; 3450 int speedupreq; 3451 int lodirty; 3452 int i; 3453 3454 /* 3455 * This process needs to be suspended prior to shutdown sync. 3456 */ 3457 EVENTHANDLER_REGISTER(shutdown_pre_sync, buf_daemon_shutdown, NULL, 3458 SHUTDOWN_PRI_LAST + 100); 3459 3460 /* 3461 * Start the buf clean daemons as children threads. 3462 */ 3463 for (i = 0 ; i < buf_domains; i++) { 3464 int error; 3465 3466 error = kthread_add((void (*)(void *))bufspace_daemon, 3467 &bdomain[i], curproc, NULL, 0, 0, "bufspacedaemon-%d", i); 3468 if (error) 3469 panic("error %d spawning bufspace daemon", error); 3470 } 3471 3472 /* 3473 * This process is allowed to take the buffer cache to the limit 3474 */ 3475 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED; 3476 mtx_lock(&bdlock); 3477 while (!bd_shutdown) { 3478 bd_request = 0; 3479 mtx_unlock(&bdlock); 3480 3481 /* 3482 * Save speedupreq for this pass and reset to capture new 3483 * requests. 3484 */ 3485 speedupreq = bd_speedupreq; 3486 bd_speedupreq = 0; 3487 3488 /* 3489 * Flush each domain sequentially according to its level and 3490 * the speedup request. 3491 */ 3492 for (i = 0; i < buf_domains; i++) { 3493 bd = &bdomain[i]; 3494 if (speedupreq) 3495 lodirty = bd->bd_numdirtybuffers / 2; 3496 else 3497 lodirty = bd->bd_lodirtybuffers; 3498 while (bd->bd_numdirtybuffers > lodirty) { 3499 if (buf_flush(NULL, bd, 3500 bd->bd_numdirtybuffers - lodirty) == 0) 3501 break; 3502 kern_yield(PRI_USER); 3503 } 3504 } 3505 3506 /* 3507 * Only clear bd_request if we have reached our low water 3508 * mark. The buf_daemon normally waits 1 second and 3509 * then incrementally flushes any dirty buffers that have 3510 * built up, within reason. 3511 * 3512 * If we were unable to hit our low water mark and couldn't 3513 * find any flushable buffers, we sleep for a short period 3514 * to avoid endless loops on unlockable buffers. 3515 */ 3516 mtx_lock(&bdlock); 3517 if (bd_shutdown) 3518 break; 3519 if (BIT_EMPTY(BUF_DOMAINS, &bdlodirty)) { 3520 /* 3521 * We reached our low water mark, reset the 3522 * request and sleep until we are needed again. 3523 * The sleep is just so the suspend code works. 3524 */ 3525 bd_request = 0; 3526 /* 3527 * Do an extra wakeup in case dirty threshold 3528 * changed via sysctl and the explicit transition 3529 * out of shortfall was missed. 3530 */ 3531 bdirtywakeup(); 3532 if (runningbufspace <= lorunningspace) 3533 runningwakeup(); 3534 msleep(&bd_request, &bdlock, PVM, "psleep", hz); 3535 } else { 3536 /* 3537 * We couldn't find any flushable dirty buffers but 3538 * still have too many dirty buffers, we 3539 * have to sleep and try again. (rare) 3540 */ 3541 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10); 3542 } 3543 } 3544 wakeup(&bd_shutdown); 3545 mtx_unlock(&bdlock); 3546 kthread_exit(); 3547 } 3548 3549 /* 3550 * flushbufqueues: 3551 * 3552 * Try to flush a buffer in the dirty queue. We must be careful to 3553 * free up B_INVAL buffers instead of write them, which NFS is 3554 * particularly sensitive to. 3555 */ 3556 static int flushwithdeps = 0; 3557 SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW | CTLFLAG_STATS, 3558 &flushwithdeps, 0, 3559 "Number of buffers flushed with dependencies that require rollbacks"); 3560 3561 static int 3562 flushbufqueues(struct vnode *lvp, struct bufdomain *bd, int target, 3563 int flushdeps) 3564 { 3565 struct bufqueue *bq; 3566 struct buf *sentinel; 3567 struct vnode *vp; 3568 struct mount *mp; 3569 struct buf *bp; 3570 int hasdeps; 3571 int flushed; 3572 int error; 3573 bool unlock; 3574 3575 flushed = 0; 3576 bq = &bd->bd_dirtyq; 3577 bp = NULL; 3578 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO); 3579 sentinel->b_qindex = QUEUE_SENTINEL; 3580 BQ_LOCK(bq); 3581 TAILQ_INSERT_HEAD(&bq->bq_queue, sentinel, b_freelist); 3582 BQ_UNLOCK(bq); 3583 while (flushed != target) { 3584 maybe_yield(); 3585 BQ_LOCK(bq); 3586 bp = TAILQ_NEXT(sentinel, b_freelist); 3587 if (bp != NULL) { 3588 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3589 TAILQ_INSERT_AFTER(&bq->bq_queue, bp, sentinel, 3590 b_freelist); 3591 } else { 3592 BQ_UNLOCK(bq); 3593 break; 3594 } 3595 /* 3596 * Skip sentinels inserted by other invocations of the 3597 * flushbufqueues(), taking care to not reorder them. 3598 * 3599 * Only flush the buffers that belong to the 3600 * vnode locked by the curthread. 3601 */ 3602 if (bp->b_qindex == QUEUE_SENTINEL || (lvp != NULL && 3603 bp->b_vp != lvp)) { 3604 BQ_UNLOCK(bq); 3605 continue; 3606 } 3607 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 3608 BQ_UNLOCK(bq); 3609 if (error != 0) 3610 continue; 3611 3612 /* 3613 * BKGRDINPROG can only be set with the buf and bufobj 3614 * locks both held. We tolerate a race to clear it here. 3615 */ 3616 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 || 3617 (bp->b_flags & B_DELWRI) == 0) { 3618 BUF_UNLOCK(bp); 3619 continue; 3620 } 3621 if (bp->b_flags & B_INVAL) { 3622 bremfreef(bp); 3623 brelse(bp); 3624 flushed++; 3625 continue; 3626 } 3627 3628 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) { 3629 if (flushdeps == 0) { 3630 BUF_UNLOCK(bp); 3631 continue; 3632 } 3633 hasdeps = 1; 3634 } else 3635 hasdeps = 0; 3636 /* 3637 * We must hold the lock on a vnode before writing 3638 * one of its buffers. Otherwise we may confuse, or 3639 * in the case of a snapshot vnode, deadlock the 3640 * system. 3641 * 3642 * The lock order here is the reverse of the normal 3643 * of vnode followed by buf lock. This is ok because 3644 * the NOWAIT will prevent deadlock. 3645 */ 3646 vp = bp->b_vp; 3647 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { 3648 BUF_UNLOCK(bp); 3649 continue; 3650 } 3651 if (lvp == NULL) { 3652 unlock = true; 3653 error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); 3654 } else { 3655 ASSERT_VOP_LOCKED(vp, "getbuf"); 3656 unlock = false; 3657 error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : 3658 vn_lock(vp, LK_TRYUPGRADE); 3659 } 3660 if (error == 0) { 3661 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", 3662 bp, bp->b_vp, bp->b_flags); 3663 if (curproc == bufdaemonproc) { 3664 vfs_bio_awrite(bp); 3665 } else { 3666 bremfree(bp); 3667 bwrite(bp); 3668 counter_u64_add(notbufdflushes, 1); 3669 } 3670 vn_finished_write(mp); 3671 if (unlock) 3672 VOP_UNLOCK(vp); 3673 flushwithdeps += hasdeps; 3674 flushed++; 3675 3676 /* 3677 * Sleeping on runningbufspace while holding 3678 * vnode lock leads to deadlock. 3679 */ 3680 if (curproc == bufdaemonproc && 3681 runningbufspace > hirunningspace) 3682 waitrunningbufspace(); 3683 continue; 3684 } 3685 vn_finished_write(mp); 3686 BUF_UNLOCK(bp); 3687 } 3688 BQ_LOCK(bq); 3689 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3690 BQ_UNLOCK(bq); 3691 free(sentinel, M_TEMP); 3692 return (flushed); 3693 } 3694 3695 /* 3696 * Check to see if a block is currently memory resident. 3697 */ 3698 struct buf * 3699 incore(struct bufobj *bo, daddr_t blkno) 3700 { 3701 return (gbincore_unlocked(bo, blkno)); 3702 } 3703 3704 /* 3705 * Returns true if no I/O is needed to access the 3706 * associated VM object. This is like incore except 3707 * it also hunts around in the VM system for the data. 3708 */ 3709 bool 3710 inmem(struct vnode * vp, daddr_t blkno) 3711 { 3712 vm_object_t obj; 3713 vm_offset_t toff, tinc, size; 3714 vm_page_t m, n; 3715 vm_ooffset_t off; 3716 int valid; 3717 3718 ASSERT_VOP_LOCKED(vp, "inmem"); 3719 3720 if (incore(&vp->v_bufobj, blkno)) 3721 return (true); 3722 if (vp->v_mount == NULL) 3723 return (false); 3724 obj = vp->v_object; 3725 if (obj == NULL) 3726 return (false); 3727 3728 size = PAGE_SIZE; 3729 if (size > vp->v_mount->mnt_stat.f_iosize) 3730 size = vp->v_mount->mnt_stat.f_iosize; 3731 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 3732 3733 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 3734 m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3735 recheck: 3736 if (m == NULL) 3737 return (false); 3738 3739 tinc = size; 3740 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 3741 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 3742 /* 3743 * Consider page validity only if page mapping didn't change 3744 * during the check. 3745 */ 3746 valid = vm_page_is_valid(m, 3747 (vm_offset_t)((toff + off) & PAGE_MASK), tinc); 3748 n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3749 if (m != n) { 3750 m = n; 3751 goto recheck; 3752 } 3753 if (!valid) 3754 return (false); 3755 } 3756 return (true); 3757 } 3758 3759 /* 3760 * Set the dirty range for a buffer based on the status of the dirty 3761 * bits in the pages comprising the buffer. The range is limited 3762 * to the size of the buffer. 3763 * 3764 * Tell the VM system that the pages associated with this buffer 3765 * are clean. This is used for delayed writes where the data is 3766 * going to go to disk eventually without additional VM intevention. 3767 * 3768 * Note that while we only really need to clean through to b_bcount, we 3769 * just go ahead and clean through to b_bufsize. 3770 */ 3771 static void 3772 vfs_clean_pages_dirty_buf(struct buf *bp) 3773 { 3774 vm_ooffset_t foff, noff, eoff; 3775 vm_page_t m; 3776 int i; 3777 3778 if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0) 3779 return; 3780 3781 foff = bp->b_offset; 3782 KASSERT(bp->b_offset != NOOFFSET, 3783 ("vfs_clean_pages_dirty_buf: no buffer offset")); 3784 3785 vfs_busy_pages_acquire(bp); 3786 vfs_setdirty_range(bp); 3787 for (i = 0; i < bp->b_npages; i++) { 3788 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3789 eoff = noff; 3790 if (eoff > bp->b_offset + bp->b_bufsize) 3791 eoff = bp->b_offset + bp->b_bufsize; 3792 m = bp->b_pages[i]; 3793 vfs_page_set_validclean(bp, foff, m); 3794 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */ 3795 foff = noff; 3796 } 3797 vfs_busy_pages_release(bp); 3798 } 3799 3800 static void 3801 vfs_setdirty_range(struct buf *bp) 3802 { 3803 vm_offset_t boffset; 3804 vm_offset_t eoffset; 3805 int i; 3806 3807 /* 3808 * test the pages to see if they have been modified directly 3809 * by users through the VM system. 3810 */ 3811 for (i = 0; i < bp->b_npages; i++) 3812 vm_page_test_dirty(bp->b_pages[i]); 3813 3814 /* 3815 * Calculate the encompassing dirty range, boffset and eoffset, 3816 * (eoffset - boffset) bytes. 3817 */ 3818 3819 for (i = 0; i < bp->b_npages; i++) { 3820 if (bp->b_pages[i]->dirty) 3821 break; 3822 } 3823 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3824 3825 for (i = bp->b_npages - 1; i >= 0; --i) { 3826 if (bp->b_pages[i]->dirty) { 3827 break; 3828 } 3829 } 3830 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3831 3832 /* 3833 * Fit it to the buffer. 3834 */ 3835 3836 if (eoffset > bp->b_bcount) 3837 eoffset = bp->b_bcount; 3838 3839 /* 3840 * If we have a good dirty range, merge with the existing 3841 * dirty range. 3842 */ 3843 3844 if (boffset < eoffset) { 3845 if (bp->b_dirtyoff > boffset) 3846 bp->b_dirtyoff = boffset; 3847 if (bp->b_dirtyend < eoffset) 3848 bp->b_dirtyend = eoffset; 3849 } 3850 } 3851 3852 /* 3853 * Allocate the KVA mapping for an existing buffer. 3854 * If an unmapped buffer is provided but a mapped buffer is requested, take 3855 * also care to properly setup mappings between pages and KVA. 3856 */ 3857 static void 3858 bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags) 3859 { 3860 int bsize, maxsize, need_mapping, need_kva; 3861 off_t offset; 3862 3863 need_mapping = bp->b_data == unmapped_buf && 3864 (gbflags & GB_UNMAPPED) == 0; 3865 need_kva = bp->b_kvabase == unmapped_buf && 3866 bp->b_data == unmapped_buf && 3867 (gbflags & GB_KVAALLOC) != 0; 3868 if (!need_mapping && !need_kva) 3869 return; 3870 3871 BUF_CHECK_UNMAPPED(bp); 3872 3873 if (need_mapping && bp->b_kvabase != unmapped_buf) { 3874 /* 3875 * Buffer is not mapped, but the KVA was already 3876 * reserved at the time of the instantiation. Use the 3877 * allocated space. 3878 */ 3879 goto has_addr; 3880 } 3881 3882 /* 3883 * Calculate the amount of the address space we would reserve 3884 * if the buffer was mapped. 3885 */ 3886 bsize = vn_isdisk(bp->b_vp) ? DEV_BSIZE : bp->b_bufobj->bo_bsize; 3887 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 3888 offset = blkno * bsize; 3889 maxsize = size + (offset & PAGE_MASK); 3890 maxsize = imax(maxsize, bsize); 3891 3892 while (bufkva_alloc(bp, maxsize, gbflags) != 0) { 3893 if ((gbflags & GB_NOWAIT_BD) != 0) { 3894 /* 3895 * XXXKIB: defragmentation cannot 3896 * succeed, not sure what else to do. 3897 */ 3898 panic("GB_NOWAIT_BD and GB_UNMAPPED %p", bp); 3899 } 3900 counter_u64_add(mappingrestarts, 1); 3901 bufspace_wait(bufdomain(bp), bp->b_vp, gbflags, 0, 0); 3902 } 3903 has_addr: 3904 if (need_mapping) { 3905 /* b_offset is handled by bpmap_qenter. */ 3906 bp->b_data = bp->b_kvabase; 3907 BUF_CHECK_MAPPED(bp); 3908 bpmap_qenter(bp); 3909 } 3910 } 3911 3912 struct buf * 3913 getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo, 3914 int flags) 3915 { 3916 struct buf *bp; 3917 int error; 3918 3919 error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp); 3920 if (error != 0) 3921 return (NULL); 3922 return (bp); 3923 } 3924 3925 /* 3926 * getblkx: 3927 * 3928 * Get a block given a specified block and offset into a file/device. 3929 * The buffers B_DONE bit will be cleared on return, making it almost 3930 * ready for an I/O initiation. B_INVAL may or may not be set on 3931 * return. The caller should clear B_INVAL prior to initiating a 3932 * READ. 3933 * 3934 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for 3935 * an existing buffer. 3936 * 3937 * For a VMIO buffer, B_CACHE is modified according to the backing VM. 3938 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set 3939 * and then cleared based on the backing VM. If the previous buffer is 3940 * non-0-sized but invalid, B_CACHE will be cleared. 3941 * 3942 * If getblk() must create a new buffer, the new buffer is returned with 3943 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which 3944 * case it is returned with B_INVAL clear and B_CACHE set based on the 3945 * backing VM. 3946 * 3947 * getblk() also forces a bwrite() for any B_DELWRI buffer whose 3948 * B_CACHE bit is clear. 3949 * 3950 * What this means, basically, is that the caller should use B_CACHE to 3951 * determine whether the buffer is fully valid or not and should clear 3952 * B_INVAL prior to issuing a read. If the caller intends to validate 3953 * the buffer by loading its data area with something, the caller needs 3954 * to clear B_INVAL. If the caller does this without issuing an I/O, 3955 * the caller should set B_CACHE ( as an optimization ), else the caller 3956 * should issue the I/O and biodone() will set B_CACHE if the I/O was 3957 * a write attempt or if it was a successful read. If the caller 3958 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR 3959 * prior to issuing the READ. biodone() will *not* clear B_INVAL. 3960 * 3961 * The blkno parameter is the logical block being requested. Normally 3962 * the mapping of logical block number to disk block address is done 3963 * by calling VOP_BMAP(). However, if the mapping is already known, the 3964 * disk block address can be passed using the dblkno parameter. If the 3965 * disk block address is not known, then the same value should be passed 3966 * for blkno and dblkno. 3967 */ 3968 int 3969 getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag, 3970 int slptimeo, int flags, struct buf **bpp) 3971 { 3972 struct buf *bp; 3973 struct bufobj *bo; 3974 daddr_t d_blkno; 3975 int bsize, error, maxsize, vmio; 3976 off_t offset; 3977 3978 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size); 3979 KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3980 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3981 if (vp->v_type != VCHR) 3982 ASSERT_VOP_LOCKED(vp, "getblk"); 3983 if (size > maxbcachebuf) 3984 panic("getblk: size(%d) > maxbcachebuf(%d)\n", size, 3985 maxbcachebuf); 3986 if (!unmapped_buf_allowed) 3987 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3988 3989 bo = &vp->v_bufobj; 3990 d_blkno = dblkno; 3991 3992 /* Attempt lockless lookup first. */ 3993 bp = gbincore_unlocked(bo, blkno); 3994 if (bp == NULL) { 3995 /* 3996 * With GB_NOCREAT we must be sure about not finding the buffer 3997 * as it may have been reassigned during unlocked lookup. 3998 */ 3999 if ((flags & GB_NOCREAT) != 0) 4000 goto loop; 4001 goto newbuf_unlocked; 4002 } 4003 4004 error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL, "getblku", 0, 4005 0); 4006 if (error != 0) 4007 goto loop; 4008 4009 /* Verify buf identify has not changed since lookup. */ 4010 if (bp->b_bufobj == bo && bp->b_lblkno == blkno) 4011 goto foundbuf_fastpath; 4012 4013 /* It changed, fallback to locked lookup. */ 4014 BUF_UNLOCK_RAW(bp); 4015 4016 loop: 4017 BO_RLOCK(bo); 4018 bp = gbincore(bo, blkno); 4019 if (bp != NULL) { 4020 int lockflags; 4021 4022 /* 4023 * Buffer is in-core. If the buffer is not busy nor managed, 4024 * it must be on a queue. 4025 */ 4026 lockflags = LK_EXCLUSIVE | LK_INTERLOCK | 4027 ((flags & GB_LOCK_NOWAIT) != 0 ? LK_NOWAIT : LK_SLEEPFAIL); 4028 #ifdef WITNESS 4029 lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0; 4030 #endif 4031 4032 error = BUF_TIMELOCK(bp, lockflags, 4033 BO_LOCKPTR(bo), "getblk", slpflag, slptimeo); 4034 4035 /* 4036 * If we slept and got the lock we have to restart in case 4037 * the buffer changed identities. 4038 */ 4039 if (error == ENOLCK) 4040 goto loop; 4041 /* We timed out or were interrupted. */ 4042 else if (error != 0) 4043 return (error); 4044 4045 foundbuf_fastpath: 4046 /* If recursed, assume caller knows the rules. */ 4047 if (BUF_LOCKRECURSED(bp)) 4048 goto end; 4049 4050 /* 4051 * The buffer is locked. B_CACHE is cleared if the buffer is 4052 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set 4053 * and for a VMIO buffer B_CACHE is adjusted according to the 4054 * backing VM cache. 4055 */ 4056 if (bp->b_flags & B_INVAL) 4057 bp->b_flags &= ~B_CACHE; 4058 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0) 4059 bp->b_flags |= B_CACHE; 4060 if (bp->b_flags & B_MANAGED) 4061 MPASS(bp->b_qindex == QUEUE_NONE); 4062 else 4063 bremfree(bp); 4064 4065 /* 4066 * check for size inconsistencies for non-VMIO case. 4067 */ 4068 if (bp->b_bcount != size) { 4069 if ((bp->b_flags & B_VMIO) == 0 || 4070 (size > bp->b_kvasize)) { 4071 if (bp->b_flags & B_DELWRI) { 4072 bp->b_flags |= B_NOCACHE; 4073 bwrite(bp); 4074 } else { 4075 if (LIST_EMPTY(&bp->b_dep)) { 4076 bp->b_flags |= B_RELBUF; 4077 brelse(bp); 4078 } else { 4079 bp->b_flags |= B_NOCACHE; 4080 bwrite(bp); 4081 } 4082 } 4083 goto loop; 4084 } 4085 } 4086 4087 /* 4088 * Handle the case of unmapped buffer which should 4089 * become mapped, or the buffer for which KVA 4090 * reservation is requested. 4091 */ 4092 bp_unmapped_get_kva(bp, blkno, size, flags); 4093 4094 /* 4095 * If the size is inconsistent in the VMIO case, we can resize 4096 * the buffer. This might lead to B_CACHE getting set or 4097 * cleared. If the size has not changed, B_CACHE remains 4098 * unchanged from its previous state. 4099 */ 4100 allocbuf(bp, size); 4101 4102 KASSERT(bp->b_offset != NOOFFSET, 4103 ("getblk: no buffer offset")); 4104 4105 /* 4106 * A buffer with B_DELWRI set and B_CACHE clear must 4107 * be committed before we can return the buffer in 4108 * order to prevent the caller from issuing a read 4109 * ( due to B_CACHE not being set ) and overwriting 4110 * it. 4111 * 4112 * Most callers, including NFS and FFS, need this to 4113 * operate properly either because they assume they 4114 * can issue a read if B_CACHE is not set, or because 4115 * ( for example ) an uncached B_DELWRI might loop due 4116 * to softupdates re-dirtying the buffer. In the latter 4117 * case, B_CACHE is set after the first write completes, 4118 * preventing further loops. 4119 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE 4120 * above while extending the buffer, we cannot allow the 4121 * buffer to remain with B_CACHE set after the write 4122 * completes or it will represent a corrupt state. To 4123 * deal with this we set B_NOCACHE to scrap the buffer 4124 * after the write. 4125 * 4126 * We might be able to do something fancy, like setting 4127 * B_CACHE in bwrite() except if B_DELWRI is already set, 4128 * so the below call doesn't set B_CACHE, but that gets real 4129 * confusing. This is much easier. 4130 */ 4131 4132 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) { 4133 bp->b_flags |= B_NOCACHE; 4134 bwrite(bp); 4135 goto loop; 4136 } 4137 bp->b_flags &= ~B_DONE; 4138 } else { 4139 /* 4140 * Buffer is not in-core, create new buffer. The buffer 4141 * returned by getnewbuf() is locked. Note that the returned 4142 * buffer is also considered valid (not marked B_INVAL). 4143 */ 4144 BO_RUNLOCK(bo); 4145 newbuf_unlocked: 4146 /* 4147 * If the user does not want us to create the buffer, bail out 4148 * here. 4149 */ 4150 if (flags & GB_NOCREAT) 4151 return (EEXIST); 4152 4153 bsize = vn_isdisk(vp) ? DEV_BSIZE : bo->bo_bsize; 4154 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 4155 offset = blkno * bsize; 4156 vmio = vp->v_object != NULL; 4157 if (vmio) { 4158 maxsize = size + (offset & PAGE_MASK); 4159 } else { 4160 maxsize = size; 4161 /* Do not allow non-VMIO notmapped buffers. */ 4162 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 4163 } 4164 maxsize = imax(maxsize, bsize); 4165 if ((flags & GB_NOSPARSE) != 0 && vmio && 4166 !vn_isdisk(vp)) { 4167 error = VOP_BMAP(vp, blkno, NULL, &d_blkno, 0, 0); 4168 KASSERT(error != EOPNOTSUPP, 4169 ("GB_NOSPARSE from fs not supporting bmap, vp %p", 4170 vp)); 4171 if (error != 0) 4172 return (error); 4173 if (d_blkno == -1) 4174 return (EJUSTRETURN); 4175 } 4176 4177 bp = getnewbuf(vp, slpflag, slptimeo, maxsize, flags); 4178 if (bp == NULL) { 4179 if (slpflag || slptimeo) 4180 return (ETIMEDOUT); 4181 /* 4182 * XXX This is here until the sleep path is diagnosed 4183 * enough to work under very low memory conditions. 4184 * 4185 * There's an issue on low memory, 4BSD+non-preempt 4186 * systems (eg MIPS routers with 32MB RAM) where buffer 4187 * exhaustion occurs without sleeping for buffer 4188 * reclaimation. This just sticks in a loop and 4189 * constantly attempts to allocate a buffer, which 4190 * hits exhaustion and tries to wakeup bufdaemon. 4191 * This never happens because we never yield. 4192 * 4193 * The real solution is to identify and fix these cases 4194 * so we aren't effectively busy-waiting in a loop 4195 * until the reclaimation path has cycles to run. 4196 */ 4197 kern_yield(PRI_USER); 4198 goto loop; 4199 } 4200 4201 /* 4202 * This code is used to make sure that a buffer is not 4203 * created while the getnewbuf routine is blocked. 4204 * This can be a problem whether the vnode is locked or not. 4205 * If the buffer is created out from under us, we have to 4206 * throw away the one we just created. 4207 * 4208 * Note: this must occur before we associate the buffer 4209 * with the vp especially considering limitations in 4210 * the splay tree implementation when dealing with duplicate 4211 * lblkno's. 4212 */ 4213 BO_LOCK(bo); 4214 if (gbincore(bo, blkno)) { 4215 BO_UNLOCK(bo); 4216 bp->b_flags |= B_INVAL; 4217 bufspace_release(bufdomain(bp), maxsize); 4218 brelse(bp); 4219 goto loop; 4220 } 4221 4222 /* 4223 * Insert the buffer into the hash, so that it can 4224 * be found by incore. 4225 */ 4226 bp->b_lblkno = blkno; 4227 bp->b_blkno = d_blkno; 4228 bp->b_offset = offset; 4229 bgetvp(vp, bp); 4230 BO_UNLOCK(bo); 4231 4232 /* 4233 * set B_VMIO bit. allocbuf() the buffer bigger. Since the 4234 * buffer size starts out as 0, B_CACHE will be set by 4235 * allocbuf() for the VMIO case prior to it testing the 4236 * backing store for validity. 4237 */ 4238 4239 if (vmio) { 4240 bp->b_flags |= B_VMIO; 4241 KASSERT(vp->v_object == bp->b_bufobj->bo_object, 4242 ("ARGH! different b_bufobj->bo_object %p %p %p\n", 4243 bp, vp->v_object, bp->b_bufobj->bo_object)); 4244 } else { 4245 bp->b_flags &= ~B_VMIO; 4246 KASSERT(bp->b_bufobj->bo_object == NULL, 4247 ("ARGH! has b_bufobj->bo_object %p %p\n", 4248 bp, bp->b_bufobj->bo_object)); 4249 BUF_CHECK_MAPPED(bp); 4250 } 4251 4252 allocbuf(bp, size); 4253 bufspace_release(bufdomain(bp), maxsize); 4254 bp->b_flags &= ~B_DONE; 4255 } 4256 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp); 4257 end: 4258 buf_track(bp, __func__); 4259 KASSERT(bp->b_bufobj == bo, 4260 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo)); 4261 *bpp = bp; 4262 return (0); 4263 } 4264 4265 /* 4266 * Get an empty, disassociated buffer of given size. The buffer is initially 4267 * set to B_INVAL. 4268 */ 4269 struct buf * 4270 geteblk(int size, int flags) 4271 { 4272 struct buf *bp; 4273 int maxsize; 4274 4275 maxsize = (size + BKVAMASK) & ~BKVAMASK; 4276 while ((bp = getnewbuf(NULL, 0, 0, maxsize, flags)) == NULL) { 4277 if ((flags & GB_NOWAIT_BD) && 4278 (curthread->td_pflags & TDP_BUFNEED) != 0) 4279 return (NULL); 4280 } 4281 allocbuf(bp, size); 4282 bufspace_release(bufdomain(bp), maxsize); 4283 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 4284 return (bp); 4285 } 4286 4287 /* 4288 * Truncate the backing store for a non-vmio buffer. 4289 */ 4290 static void 4291 vfs_nonvmio_truncate(struct buf *bp, int newbsize) 4292 { 4293 4294 if (bp->b_flags & B_MALLOC) { 4295 /* 4296 * malloced buffers are not shrunk 4297 */ 4298 if (newbsize == 0) { 4299 bufmallocadjust(bp, 0); 4300 free(bp->b_data, M_BIOBUF); 4301 bp->b_data = bp->b_kvabase; 4302 bp->b_flags &= ~B_MALLOC; 4303 } 4304 return; 4305 } 4306 vm_hold_free_pages(bp, newbsize); 4307 bufspace_adjust(bp, newbsize); 4308 } 4309 4310 /* 4311 * Extend the backing for a non-VMIO buffer. 4312 */ 4313 static void 4314 vfs_nonvmio_extend(struct buf *bp, int newbsize) 4315 { 4316 caddr_t origbuf; 4317 int origbufsize; 4318 4319 /* 4320 * We only use malloced memory on the first allocation. 4321 * and revert to page-allocated memory when the buffer 4322 * grows. 4323 * 4324 * There is a potential smp race here that could lead 4325 * to bufmallocspace slightly passing the max. It 4326 * is probably extremely rare and not worth worrying 4327 * over. 4328 */ 4329 if (bp->b_bufsize == 0 && newbsize <= PAGE_SIZE/2 && 4330 bufmallocspace < maxbufmallocspace) { 4331 bp->b_data = malloc(newbsize, M_BIOBUF, M_WAITOK); 4332 bp->b_flags |= B_MALLOC; 4333 bufmallocadjust(bp, newbsize); 4334 return; 4335 } 4336 4337 /* 4338 * If the buffer is growing on its other-than-first 4339 * allocation then we revert to the page-allocation 4340 * scheme. 4341 */ 4342 origbuf = NULL; 4343 origbufsize = 0; 4344 if (bp->b_flags & B_MALLOC) { 4345 origbuf = bp->b_data; 4346 origbufsize = bp->b_bufsize; 4347 bp->b_data = bp->b_kvabase; 4348 bufmallocadjust(bp, 0); 4349 bp->b_flags &= ~B_MALLOC; 4350 newbsize = round_page(newbsize); 4351 } 4352 vm_hold_load_pages(bp, (vm_offset_t) bp->b_data + bp->b_bufsize, 4353 (vm_offset_t) bp->b_data + newbsize); 4354 if (origbuf != NULL) { 4355 bcopy(origbuf, bp->b_data, origbufsize); 4356 free(origbuf, M_BIOBUF); 4357 } 4358 bufspace_adjust(bp, newbsize); 4359 } 4360 4361 /* 4362 * This code constitutes the buffer memory from either anonymous system 4363 * memory (in the case of non-VMIO operations) or from an associated 4364 * VM object (in the case of VMIO operations). This code is able to 4365 * resize a buffer up or down. 4366 * 4367 * Note that this code is tricky, and has many complications to resolve 4368 * deadlock or inconsistent data situations. Tread lightly!!! 4369 * There are B_CACHE and B_DELWRI interactions that must be dealt with by 4370 * the caller. Calling this code willy nilly can result in the loss of data. 4371 * 4372 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with 4373 * B_CACHE for the non-VMIO case. 4374 */ 4375 int 4376 allocbuf(struct buf *bp, int size) 4377 { 4378 int newbsize; 4379 4380 if (bp->b_bcount == size) 4381 return (1); 4382 4383 KASSERT(bp->b_kvasize == 0 || bp->b_kvasize >= size, 4384 ("allocbuf: buffer too small %p %#x %#x", 4385 bp, bp->b_kvasize, size)); 4386 4387 newbsize = roundup2(size, DEV_BSIZE); 4388 if ((bp->b_flags & B_VMIO) == 0) { 4389 if ((bp->b_flags & B_MALLOC) == 0) 4390 newbsize = round_page(newbsize); 4391 /* 4392 * Just get anonymous memory from the kernel. Don't 4393 * mess with B_CACHE. 4394 */ 4395 if (newbsize < bp->b_bufsize) 4396 vfs_nonvmio_truncate(bp, newbsize); 4397 else if (newbsize > bp->b_bufsize) 4398 vfs_nonvmio_extend(bp, newbsize); 4399 } else { 4400 int desiredpages; 4401 4402 desiredpages = size == 0 ? 0 : 4403 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 4404 4405 KASSERT((bp->b_flags & B_MALLOC) == 0, 4406 ("allocbuf: VMIO buffer can't be malloced %p", bp)); 4407 4408 /* 4409 * Set B_CACHE initially if buffer is 0 length or will become 4410 * 0-length. 4411 */ 4412 if (size == 0 || bp->b_bufsize == 0) 4413 bp->b_flags |= B_CACHE; 4414 4415 if (newbsize < bp->b_bufsize) 4416 vfs_vmio_truncate(bp, desiredpages); 4417 /* XXX This looks as if it should be newbsize > b_bufsize */ 4418 else if (size > bp->b_bcount) 4419 vfs_vmio_extend(bp, desiredpages, size); 4420 bufspace_adjust(bp, newbsize); 4421 } 4422 bp->b_bcount = size; /* requested buffer size. */ 4423 return (1); 4424 } 4425 4426 extern int inflight_transient_maps; 4427 4428 static struct bio_queue nondump_bios; 4429 4430 void 4431 biodone(struct bio *bp) 4432 { 4433 struct mtx *mtxp; 4434 void (*done)(struct bio *); 4435 vm_offset_t start, end; 4436 4437 biotrack(bp, __func__); 4438 4439 /* 4440 * Avoid completing I/O when dumping after a panic since that may 4441 * result in a deadlock in the filesystem or pager code. Note that 4442 * this doesn't affect dumps that were started manually since we aim 4443 * to keep the system usable after it has been resumed. 4444 */ 4445 if (__predict_false(dumping && SCHEDULER_STOPPED())) { 4446 TAILQ_INSERT_HEAD(&nondump_bios, bp, bio_queue); 4447 return; 4448 } 4449 if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { 4450 bp->bio_flags &= ~BIO_TRANSIENT_MAPPING; 4451 bp->bio_flags |= BIO_UNMAPPED; 4452 start = trunc_page((vm_offset_t)bp->bio_data); 4453 end = round_page((vm_offset_t)bp->bio_data + bp->bio_length); 4454 bp->bio_data = unmapped_buf; 4455 pmap_qremove(start, atop(end - start)); 4456 vmem_free(transient_arena, start, end - start); 4457 atomic_add_int(&inflight_transient_maps, -1); 4458 } 4459 done = bp->bio_done; 4460 /* 4461 * The check for done == biodone is to allow biodone to be 4462 * used as a bio_done routine. 4463 */ 4464 if (done == NULL || done == biodone) { 4465 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4466 mtx_lock(mtxp); 4467 bp->bio_flags |= BIO_DONE; 4468 wakeup(bp); 4469 mtx_unlock(mtxp); 4470 } else 4471 done(bp); 4472 } 4473 4474 /* 4475 * Wait for a BIO to finish. 4476 */ 4477 int 4478 biowait(struct bio *bp, const char *wmesg) 4479 { 4480 struct mtx *mtxp; 4481 4482 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4483 mtx_lock(mtxp); 4484 while ((bp->bio_flags & BIO_DONE) == 0) 4485 msleep(bp, mtxp, PRIBIO, wmesg, 0); 4486 mtx_unlock(mtxp); 4487 if (bp->bio_error != 0) 4488 return (bp->bio_error); 4489 if (!(bp->bio_flags & BIO_ERROR)) 4490 return (0); 4491 return (EIO); 4492 } 4493 4494 void 4495 biofinish(struct bio *bp, struct devstat *stat, int error) 4496 { 4497 4498 if (error) { 4499 bp->bio_error = error; 4500 bp->bio_flags |= BIO_ERROR; 4501 } 4502 if (stat != NULL) 4503 devstat_end_transaction_bio(stat, bp); 4504 biodone(bp); 4505 } 4506 4507 #if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING) 4508 void 4509 biotrack_buf(struct bio *bp, const char *location) 4510 { 4511 4512 buf_track(bp->bio_track_bp, location); 4513 } 4514 #endif 4515 4516 /* 4517 * bufwait: 4518 * 4519 * Wait for buffer I/O completion, returning error status. The buffer 4520 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR 4521 * error and cleared. 4522 */ 4523 int 4524 bufwait(struct buf *bp) 4525 { 4526 if (bp->b_iocmd == BIO_READ) 4527 bwait(bp, PRIBIO, "biord"); 4528 else 4529 bwait(bp, PRIBIO, "biowr"); 4530 if (bp->b_flags & B_EINTR) { 4531 bp->b_flags &= ~B_EINTR; 4532 return (EINTR); 4533 } 4534 if (bp->b_ioflags & BIO_ERROR) { 4535 return (bp->b_error ? bp->b_error : EIO); 4536 } else { 4537 return (0); 4538 } 4539 } 4540 4541 /* 4542 * bufdone: 4543 * 4544 * Finish I/O on a buffer, optionally calling a completion function. 4545 * This is usually called from an interrupt so process blocking is 4546 * not allowed. 4547 * 4548 * biodone is also responsible for setting B_CACHE in a B_VMIO bp. 4549 * In a non-VMIO bp, B_CACHE will be set on the next getblk() 4550 * assuming B_INVAL is clear. 4551 * 4552 * For the VMIO case, we set B_CACHE if the op was a read and no 4553 * read error occurred, or if the op was a write. B_CACHE is never 4554 * set if the buffer is invalid or otherwise uncacheable. 4555 * 4556 * bufdone does not mess with B_INVAL, allowing the I/O routine or the 4557 * initiator to leave B_INVAL set to brelse the buffer out of existence 4558 * in the biodone routine. 4559 */ 4560 void 4561 bufdone(struct buf *bp) 4562 { 4563 struct bufobj *dropobj; 4564 void (*biodone)(struct buf *); 4565 4566 buf_track(bp, __func__); 4567 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 4568 dropobj = NULL; 4569 4570 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp)); 4571 4572 runningbufwakeup(bp); 4573 if (bp->b_iocmd == BIO_WRITE) 4574 dropobj = bp->b_bufobj; 4575 /* call optional completion function if requested */ 4576 if (bp->b_iodone != NULL) { 4577 biodone = bp->b_iodone; 4578 bp->b_iodone = NULL; 4579 (*biodone) (bp); 4580 if (dropobj) 4581 bufobj_wdrop(dropobj); 4582 return; 4583 } 4584 if (bp->b_flags & B_VMIO) { 4585 /* 4586 * Set B_CACHE if the op was a normal read and no error 4587 * occurred. B_CACHE is set for writes in the b*write() 4588 * routines. 4589 */ 4590 if (bp->b_iocmd == BIO_READ && 4591 !(bp->b_flags & (B_INVAL|B_NOCACHE)) && 4592 !(bp->b_ioflags & BIO_ERROR)) 4593 bp->b_flags |= B_CACHE; 4594 vfs_vmio_iodone(bp); 4595 } 4596 if (!LIST_EMPTY(&bp->b_dep)) 4597 buf_complete(bp); 4598 if ((bp->b_flags & B_CKHASH) != 0) { 4599 KASSERT(bp->b_iocmd == BIO_READ, 4600 ("bufdone: b_iocmd %d not BIO_READ", bp->b_iocmd)); 4601 KASSERT(buf_mapped(bp), ("bufdone: bp %p not mapped", bp)); 4602 (*bp->b_ckhashcalc)(bp); 4603 } 4604 /* 4605 * For asynchronous completions, release the buffer now. The brelse 4606 * will do a wakeup there if necessary - so no need to do a wakeup 4607 * here in the async case. The sync case always needs to do a wakeup. 4608 */ 4609 if (bp->b_flags & B_ASYNC) { 4610 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || 4611 (bp->b_ioflags & BIO_ERROR)) 4612 brelse(bp); 4613 else 4614 bqrelse(bp); 4615 } else 4616 bdone(bp); 4617 if (dropobj) 4618 bufobj_wdrop(dropobj); 4619 } 4620 4621 /* 4622 * This routine is called in lieu of iodone in the case of 4623 * incomplete I/O. This keeps the busy status for pages 4624 * consistent. 4625 */ 4626 void 4627 vfs_unbusy_pages(struct buf *bp) 4628 { 4629 int i; 4630 vm_object_t obj; 4631 vm_page_t m; 4632 4633 runningbufwakeup(bp); 4634 if (!(bp->b_flags & B_VMIO)) 4635 return; 4636 4637 obj = bp->b_bufobj->bo_object; 4638 for (i = 0; i < bp->b_npages; i++) { 4639 m = bp->b_pages[i]; 4640 if (m == bogus_page) { 4641 m = vm_page_relookup(obj, OFF_TO_IDX(bp->b_offset) + i); 4642 if (!m) 4643 panic("vfs_unbusy_pages: page missing\n"); 4644 bp->b_pages[i] = m; 4645 if (buf_mapped(bp)) { 4646 BUF_CHECK_MAPPED(bp); 4647 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4648 bp->b_pages, bp->b_npages); 4649 } else 4650 BUF_CHECK_UNMAPPED(bp); 4651 } 4652 vm_page_sunbusy(m); 4653 } 4654 vm_object_pip_wakeupn(obj, bp->b_npages); 4655 } 4656 4657 /* 4658 * vfs_page_set_valid: 4659 * 4660 * Set the valid bits in a page based on the supplied offset. The 4661 * range is restricted to the buffer's size. 4662 * 4663 * This routine is typically called after a read completes. 4664 */ 4665 static void 4666 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4667 { 4668 vm_ooffset_t eoff; 4669 4670 /* 4671 * Compute the end offset, eoff, such that [off, eoff) does not span a 4672 * page boundary and eoff is not greater than the end of the buffer. 4673 * The end of the buffer, in this case, is our file EOF, not the 4674 * allocation size of the buffer. 4675 */ 4676 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK; 4677 if (eoff > bp->b_offset + bp->b_bcount) 4678 eoff = bp->b_offset + bp->b_bcount; 4679 4680 /* 4681 * Set valid range. This is typically the entire buffer and thus the 4682 * entire page. 4683 */ 4684 if (eoff > off) 4685 vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off); 4686 } 4687 4688 /* 4689 * vfs_page_set_validclean: 4690 * 4691 * Set the valid bits and clear the dirty bits in a page based on the 4692 * supplied offset. The range is restricted to the buffer's size. 4693 */ 4694 static void 4695 vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4696 { 4697 vm_ooffset_t soff, eoff; 4698 4699 /* 4700 * Start and end offsets in buffer. eoff - soff may not cross a 4701 * page boundary or cross the end of the buffer. The end of the 4702 * buffer, in this case, is our file EOF, not the allocation size 4703 * of the buffer. 4704 */ 4705 soff = off; 4706 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4707 if (eoff > bp->b_offset + bp->b_bcount) 4708 eoff = bp->b_offset + bp->b_bcount; 4709 4710 /* 4711 * Set valid range. This is typically the entire buffer and thus the 4712 * entire page. 4713 */ 4714 if (eoff > soff) { 4715 vm_page_set_validclean( 4716 m, 4717 (vm_offset_t) (soff & PAGE_MASK), 4718 (vm_offset_t) (eoff - soff) 4719 ); 4720 } 4721 } 4722 4723 /* 4724 * Acquire a shared busy on all pages in the buf. 4725 */ 4726 void 4727 vfs_busy_pages_acquire(struct buf *bp) 4728 { 4729 int i; 4730 4731 for (i = 0; i < bp->b_npages; i++) 4732 vm_page_busy_acquire(bp->b_pages[i], VM_ALLOC_SBUSY); 4733 } 4734 4735 void 4736 vfs_busy_pages_release(struct buf *bp) 4737 { 4738 int i; 4739 4740 for (i = 0; i < bp->b_npages; i++) 4741 vm_page_sunbusy(bp->b_pages[i]); 4742 } 4743 4744 /* 4745 * This routine is called before a device strategy routine. 4746 * It is used to tell the VM system that paging I/O is in 4747 * progress, and treat the pages associated with the buffer 4748 * almost as being exclusive busy. Also the object paging_in_progress 4749 * flag is handled to make sure that the object doesn't become 4750 * inconsistent. 4751 * 4752 * Since I/O has not been initiated yet, certain buffer flags 4753 * such as BIO_ERROR or B_INVAL may be in an inconsistent state 4754 * and should be ignored. 4755 */ 4756 void 4757 vfs_busy_pages(struct buf *bp, int clear_modify) 4758 { 4759 vm_object_t obj; 4760 vm_ooffset_t foff; 4761 vm_page_t m; 4762 int i; 4763 bool bogus; 4764 4765 if (!(bp->b_flags & B_VMIO)) 4766 return; 4767 4768 obj = bp->b_bufobj->bo_object; 4769 foff = bp->b_offset; 4770 KASSERT(bp->b_offset != NOOFFSET, 4771 ("vfs_busy_pages: no buffer offset")); 4772 if ((bp->b_flags & B_CLUSTER) == 0) { 4773 vm_object_pip_add(obj, bp->b_npages); 4774 vfs_busy_pages_acquire(bp); 4775 } 4776 if (bp->b_bufsize != 0) 4777 vfs_setdirty_range(bp); 4778 bogus = false; 4779 for (i = 0; i < bp->b_npages; i++) { 4780 m = bp->b_pages[i]; 4781 vm_page_assert_sbusied(m); 4782 4783 /* 4784 * When readying a buffer for a read ( i.e 4785 * clear_modify == 0 ), it is important to do 4786 * bogus_page replacement for valid pages in 4787 * partially instantiated buffers. Partially 4788 * instantiated buffers can, in turn, occur when 4789 * reconstituting a buffer from its VM backing store 4790 * base. We only have to do this if B_CACHE is 4791 * clear ( which causes the I/O to occur in the 4792 * first place ). The replacement prevents the read 4793 * I/O from overwriting potentially dirty VM-backed 4794 * pages. XXX bogus page replacement is, uh, bogus. 4795 * It may not work properly with small-block devices. 4796 * We need to find a better way. 4797 */ 4798 if (clear_modify) { 4799 pmap_remove_write(m); 4800 vfs_page_set_validclean(bp, foff, m); 4801 } else if (vm_page_all_valid(m) && 4802 (bp->b_flags & B_CACHE) == 0) { 4803 bp->b_pages[i] = bogus_page; 4804 bogus = true; 4805 } 4806 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4807 } 4808 if (bogus && buf_mapped(bp)) { 4809 BUF_CHECK_MAPPED(bp); 4810 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4811 bp->b_pages, bp->b_npages); 4812 } 4813 } 4814 4815 /* 4816 * vfs_bio_set_valid: 4817 * 4818 * Set the range within the buffer to valid. The range is 4819 * relative to the beginning of the buffer, b_offset. Note that 4820 * b_offset itself may be offset from the beginning of the first 4821 * page. 4822 */ 4823 void 4824 vfs_bio_set_valid(struct buf *bp, int base, int size) 4825 { 4826 int i, n; 4827 vm_page_t m; 4828 4829 if (!(bp->b_flags & B_VMIO)) 4830 return; 4831 4832 /* 4833 * Fixup base to be relative to beginning of first page. 4834 * Set initial n to be the maximum number of bytes in the 4835 * first page that can be validated. 4836 */ 4837 base += (bp->b_offset & PAGE_MASK); 4838 n = PAGE_SIZE - (base & PAGE_MASK); 4839 4840 /* 4841 * Busy may not be strictly necessary here because the pages are 4842 * unlikely to be fully valid and the vnode lock will synchronize 4843 * their access via getpages. It is grabbed for consistency with 4844 * other page validation. 4845 */ 4846 vfs_busy_pages_acquire(bp); 4847 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4848 m = bp->b_pages[i]; 4849 if (n > size) 4850 n = size; 4851 vm_page_set_valid_range(m, base & PAGE_MASK, n); 4852 base += n; 4853 size -= n; 4854 n = PAGE_SIZE; 4855 } 4856 vfs_busy_pages_release(bp); 4857 } 4858 4859 /* 4860 * vfs_bio_clrbuf: 4861 * 4862 * If the specified buffer is a non-VMIO buffer, clear the entire 4863 * buffer. If the specified buffer is a VMIO buffer, clear and 4864 * validate only the previously invalid portions of the buffer. 4865 * This routine essentially fakes an I/O, so we need to clear 4866 * BIO_ERROR and B_INVAL. 4867 * 4868 * Note that while we only theoretically need to clear through b_bcount, 4869 * we go ahead and clear through b_bufsize. 4870 */ 4871 void 4872 vfs_bio_clrbuf(struct buf *bp) 4873 { 4874 int i, j, sa, ea, slide, zbits; 4875 vm_page_bits_t mask; 4876 4877 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) { 4878 clrbuf(bp); 4879 return; 4880 } 4881 bp->b_flags &= ~B_INVAL; 4882 bp->b_ioflags &= ~BIO_ERROR; 4883 vfs_busy_pages_acquire(bp); 4884 sa = bp->b_offset & PAGE_MASK; 4885 slide = 0; 4886 for (i = 0; i < bp->b_npages; i++, sa = 0) { 4887 slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize); 4888 ea = slide & PAGE_MASK; 4889 if (ea == 0) 4890 ea = PAGE_SIZE; 4891 if (bp->b_pages[i] == bogus_page) 4892 continue; 4893 j = sa / DEV_BSIZE; 4894 zbits = (sizeof(vm_page_bits_t) * NBBY) - 4895 (ea - sa) / DEV_BSIZE; 4896 mask = (VM_PAGE_BITS_ALL >> zbits) << j; 4897 if ((bp->b_pages[i]->valid & mask) == mask) 4898 continue; 4899 if ((bp->b_pages[i]->valid & mask) == 0) 4900 pmap_zero_page_area(bp->b_pages[i], sa, ea - sa); 4901 else { 4902 for (; sa < ea; sa += DEV_BSIZE, j++) { 4903 if ((bp->b_pages[i]->valid & (1 << j)) == 0) { 4904 pmap_zero_page_area(bp->b_pages[i], 4905 sa, DEV_BSIZE); 4906 } 4907 } 4908 } 4909 vm_page_set_valid_range(bp->b_pages[i], j * DEV_BSIZE, 4910 roundup2(ea - sa, DEV_BSIZE)); 4911 } 4912 vfs_busy_pages_release(bp); 4913 bp->b_resid = 0; 4914 } 4915 4916 void 4917 vfs_bio_bzero_buf(struct buf *bp, int base, int size) 4918 { 4919 vm_page_t m; 4920 int i, n; 4921 4922 if (buf_mapped(bp)) { 4923 BUF_CHECK_MAPPED(bp); 4924 bzero(bp->b_data + base, size); 4925 } else { 4926 BUF_CHECK_UNMAPPED(bp); 4927 n = PAGE_SIZE - (base & PAGE_MASK); 4928 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4929 m = bp->b_pages[i]; 4930 if (n > size) 4931 n = size; 4932 pmap_zero_page_area(m, base & PAGE_MASK, n); 4933 base += n; 4934 size -= n; 4935 n = PAGE_SIZE; 4936 } 4937 } 4938 } 4939 4940 /* 4941 * Update buffer flags based on I/O request parameters, optionally releasing the 4942 * buffer. If it's VMIO or direct I/O, the buffer pages are released to the VM, 4943 * where they may be placed on a page queue (VMIO) or freed immediately (direct 4944 * I/O). Otherwise the buffer is released to the cache. 4945 */ 4946 static void 4947 b_io_dismiss(struct buf *bp, int ioflag, bool release) 4948 { 4949 4950 KASSERT((ioflag & IO_NOREUSE) == 0 || (ioflag & IO_VMIO) != 0, 4951 ("buf %p non-VMIO noreuse", bp)); 4952 4953 if ((ioflag & IO_DIRECT) != 0) 4954 bp->b_flags |= B_DIRECT; 4955 if ((ioflag & IO_EXT) != 0) 4956 bp->b_xflags |= BX_ALTDATA; 4957 if ((ioflag & (IO_VMIO | IO_DIRECT)) != 0 && LIST_EMPTY(&bp->b_dep)) { 4958 bp->b_flags |= B_RELBUF; 4959 if ((ioflag & IO_NOREUSE) != 0) 4960 bp->b_flags |= B_NOREUSE; 4961 if (release) 4962 brelse(bp); 4963 } else if (release) 4964 bqrelse(bp); 4965 } 4966 4967 void 4968 vfs_bio_brelse(struct buf *bp, int ioflag) 4969 { 4970 4971 b_io_dismiss(bp, ioflag, true); 4972 } 4973 4974 void 4975 vfs_bio_set_flags(struct buf *bp, int ioflag) 4976 { 4977 4978 b_io_dismiss(bp, ioflag, false); 4979 } 4980 4981 /* 4982 * vm_hold_load_pages and vm_hold_free_pages get pages into 4983 * a buffers address space. The pages are anonymous and are 4984 * not associated with a file object. 4985 */ 4986 static void 4987 vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to) 4988 { 4989 vm_offset_t pg; 4990 vm_page_t p; 4991 int index; 4992 4993 BUF_CHECK_MAPPED(bp); 4994 4995 to = round_page(to); 4996 from = round_page(from); 4997 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 4998 MPASS((bp->b_flags & B_MAXPHYS) == 0); 4999 KASSERT(to - from <= maxbcachebuf, 5000 ("vm_hold_load_pages too large %p %#jx %#jx %u", 5001 bp, (uintmax_t)from, (uintmax_t)to, maxbcachebuf)); 5002 5003 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 5004 /* 5005 * note: must allocate system pages since blocking here 5006 * could interfere with paging I/O, no matter which 5007 * process we are. 5008 */ 5009 p = vm_page_alloc_noobj(VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | 5010 VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT) | VM_ALLOC_WAITOK); 5011 pmap_qenter(pg, &p, 1); 5012 bp->b_pages[index] = p; 5013 } 5014 bp->b_npages = index; 5015 } 5016 5017 /* Return pages associated with this buf to the vm system */ 5018 static void 5019 vm_hold_free_pages(struct buf *bp, int newbsize) 5020 { 5021 vm_offset_t from; 5022 vm_page_t p; 5023 int index, newnpages; 5024 5025 BUF_CHECK_MAPPED(bp); 5026 5027 from = round_page((vm_offset_t)bp->b_data + newbsize); 5028 newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 5029 if (bp->b_npages > newnpages) 5030 pmap_qremove(from, bp->b_npages - newnpages); 5031 for (index = newnpages; index < bp->b_npages; index++) { 5032 p = bp->b_pages[index]; 5033 bp->b_pages[index] = NULL; 5034 vm_page_unwire_noq(p); 5035 vm_page_free(p); 5036 } 5037 bp->b_npages = newnpages; 5038 } 5039 5040 /* 5041 * Map an IO request into kernel virtual address space. 5042 * 5043 * All requests are (re)mapped into kernel VA space. 5044 * Notice that we use b_bufsize for the size of the buffer 5045 * to be mapped. b_bcount might be modified by the driver. 5046 * 5047 * Note that even if the caller determines that the address space should 5048 * be valid, a race or a smaller-file mapped into a larger space may 5049 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST 5050 * check the return value. 5051 * 5052 * This function only works with pager buffers. 5053 */ 5054 int 5055 vmapbuf(struct buf *bp, void *uaddr, size_t len, int mapbuf) 5056 { 5057 vm_prot_t prot; 5058 int pidx; 5059 5060 MPASS((bp->b_flags & B_MAXPHYS) != 0); 5061 prot = VM_PROT_READ; 5062 if (bp->b_iocmd == BIO_READ) 5063 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 5064 pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 5065 (vm_offset_t)uaddr, len, prot, bp->b_pages, PBUF_PAGES); 5066 if (pidx < 0) 5067 return (-1); 5068 bp->b_bufsize = len; 5069 bp->b_npages = pidx; 5070 bp->b_offset = ((vm_offset_t)uaddr) & PAGE_MASK; 5071 if (mapbuf || !unmapped_buf_allowed) { 5072 pmap_qenter((vm_offset_t)bp->b_kvabase, bp->b_pages, pidx); 5073 bp->b_data = bp->b_kvabase + bp->b_offset; 5074 } else 5075 bp->b_data = unmapped_buf; 5076 return (0); 5077 } 5078 5079 /* 5080 * Free the io map PTEs associated with this IO operation. 5081 * We also invalidate the TLB entries and restore the original b_addr. 5082 * 5083 * This function only works with pager buffers. 5084 */ 5085 void 5086 vunmapbuf(struct buf *bp) 5087 { 5088 int npages; 5089 5090 npages = bp->b_npages; 5091 if (buf_mapped(bp)) 5092 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages); 5093 vm_page_unhold_pages(bp->b_pages, npages); 5094 5095 bp->b_data = unmapped_buf; 5096 } 5097 5098 void 5099 bdone(struct buf *bp) 5100 { 5101 struct mtx *mtxp; 5102 5103 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5104 mtx_lock(mtxp); 5105 bp->b_flags |= B_DONE; 5106 wakeup(bp); 5107 mtx_unlock(mtxp); 5108 } 5109 5110 void 5111 bwait(struct buf *bp, u_char pri, const char *wchan) 5112 { 5113 struct mtx *mtxp; 5114 5115 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5116 mtx_lock(mtxp); 5117 while ((bp->b_flags & B_DONE) == 0) 5118 msleep(bp, mtxp, pri, wchan, 0); 5119 mtx_unlock(mtxp); 5120 } 5121 5122 int 5123 bufsync(struct bufobj *bo, int waitfor) 5124 { 5125 5126 return (VOP_FSYNC(bo2vnode(bo), waitfor, curthread)); 5127 } 5128 5129 void 5130 bufstrategy(struct bufobj *bo, struct buf *bp) 5131 { 5132 int i __unused; 5133 struct vnode *vp; 5134 5135 vp = bp->b_vp; 5136 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy")); 5137 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 5138 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp)); 5139 i = VOP_STRATEGY(vp, bp); 5140 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp)); 5141 } 5142 5143 /* 5144 * Initialize a struct bufobj before use. Memory is assumed zero filled. 5145 */ 5146 void 5147 bufobj_init(struct bufobj *bo, void *private) 5148 { 5149 static volatile int bufobj_cleanq; 5150 5151 bo->bo_domain = 5152 atomic_fetchadd_int(&bufobj_cleanq, 1) % buf_domains; 5153 rw_init(BO_LOCKPTR(bo), "bufobj interlock"); 5154 bo->bo_private = private; 5155 TAILQ_INIT(&bo->bo_clean.bv_hd); 5156 pctrie_init(&bo->bo_clean.bv_root); 5157 TAILQ_INIT(&bo->bo_dirty.bv_hd); 5158 pctrie_init(&bo->bo_dirty.bv_root); 5159 } 5160 5161 void 5162 bufobj_wrefl(struct bufobj *bo) 5163 { 5164 5165 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5166 ASSERT_BO_WLOCKED(bo); 5167 bo->bo_numoutput++; 5168 } 5169 5170 void 5171 bufobj_wref(struct bufobj *bo) 5172 { 5173 5174 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5175 BO_LOCK(bo); 5176 bo->bo_numoutput++; 5177 BO_UNLOCK(bo); 5178 } 5179 5180 void 5181 bufobj_wdrop(struct bufobj *bo) 5182 { 5183 5184 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop")); 5185 BO_LOCK(bo); 5186 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count")); 5187 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) { 5188 bo->bo_flag &= ~BO_WWAIT; 5189 wakeup(&bo->bo_numoutput); 5190 } 5191 BO_UNLOCK(bo); 5192 } 5193 5194 int 5195 bufobj_wwait(struct bufobj *bo, int slpflag, int timeo) 5196 { 5197 int error; 5198 5199 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait")); 5200 ASSERT_BO_WLOCKED(bo); 5201 error = 0; 5202 while (bo->bo_numoutput) { 5203 bo->bo_flag |= BO_WWAIT; 5204 error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo), 5205 slpflag | (PRIBIO + 1), "bo_wwait", timeo); 5206 if (error) 5207 break; 5208 } 5209 return (error); 5210 } 5211 5212 /* 5213 * Set bio_data or bio_ma for struct bio from the struct buf. 5214 */ 5215 void 5216 bdata2bio(struct buf *bp, struct bio *bip) 5217 { 5218 5219 if (!buf_mapped(bp)) { 5220 KASSERT(unmapped_buf_allowed, ("unmapped")); 5221 bip->bio_ma = bp->b_pages; 5222 bip->bio_ma_n = bp->b_npages; 5223 bip->bio_data = unmapped_buf; 5224 bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK; 5225 bip->bio_flags |= BIO_UNMAPPED; 5226 KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) / 5227 PAGE_SIZE == bp->b_npages, 5228 ("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset, 5229 (long long)bip->bio_length, bip->bio_ma_n)); 5230 } else { 5231 bip->bio_data = bp->b_data; 5232 bip->bio_ma = NULL; 5233 } 5234 } 5235 5236 static int buf_pager_relbuf; 5237 SYSCTL_INT(_vfs, OID_AUTO, buf_pager_relbuf, CTLFLAG_RWTUN, 5238 &buf_pager_relbuf, 0, 5239 "Make buffer pager release buffers after reading"); 5240 5241 /* 5242 * The buffer pager. It uses buffer reads to validate pages. 5243 * 5244 * In contrast to the generic local pager from vm/vnode_pager.c, this 5245 * pager correctly and easily handles volumes where the underlying 5246 * device block size is greater than the machine page size. The 5247 * buffer cache transparently extends the requested page run to be 5248 * aligned at the block boundary, and does the necessary bogus page 5249 * replacements in the addends to avoid obliterating already valid 5250 * pages. 5251 * 5252 * The only non-trivial issue is that the exclusive busy state for 5253 * pages, which is assumed by the vm_pager_getpages() interface, is 5254 * incompatible with the VMIO buffer cache's desire to share-busy the 5255 * pages. This function performs a trivial downgrade of the pages' 5256 * state before reading buffers, and a less trivial upgrade from the 5257 * shared-busy to excl-busy state after the read. 5258 */ 5259 int 5260 vfs_bio_getpages(struct vnode *vp, vm_page_t *ma, int count, 5261 int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno, 5262 vbg_get_blksize_t get_blksize) 5263 { 5264 vm_page_t m; 5265 vm_object_t object; 5266 struct buf *bp; 5267 struct mount *mp; 5268 daddr_t lbn, lbnp; 5269 vm_ooffset_t la, lb, poff, poffe; 5270 long bo_bs, bsize; 5271 int br_flags, error, i, pgsin, pgsin_a, pgsin_b; 5272 bool redo, lpart; 5273 5274 object = vp->v_object; 5275 mp = vp->v_mount; 5276 error = 0; 5277 la = IDX_TO_OFF(ma[count - 1]->pindex); 5278 if (la >= object->un_pager.vnp.vnp_size) 5279 return (VM_PAGER_BAD); 5280 5281 /* 5282 * Change the meaning of la from where the last requested page starts 5283 * to where it ends, because that's the end of the requested region 5284 * and the start of the potential read-ahead region. 5285 */ 5286 la += PAGE_SIZE; 5287 lpart = la > object->un_pager.vnp.vnp_size; 5288 error = get_blksize(vp, get_lblkno(vp, IDX_TO_OFF(ma[0]->pindex)), 5289 &bo_bs); 5290 if (error != 0) 5291 return (VM_PAGER_ERROR); 5292 5293 /* 5294 * Calculate read-ahead, behind and total pages. 5295 */ 5296 pgsin = count; 5297 lb = IDX_TO_OFF(ma[0]->pindex); 5298 pgsin_b = OFF_TO_IDX(lb - rounddown2(lb, bo_bs)); 5299 pgsin += pgsin_b; 5300 if (rbehind != NULL) 5301 *rbehind = pgsin_b; 5302 pgsin_a = OFF_TO_IDX(roundup2(la, bo_bs) - la); 5303 if (la + IDX_TO_OFF(pgsin_a) >= object->un_pager.vnp.vnp_size) 5304 pgsin_a = OFF_TO_IDX(roundup2(object->un_pager.vnp.vnp_size, 5305 PAGE_SIZE) - la); 5306 pgsin += pgsin_a; 5307 if (rahead != NULL) 5308 *rahead = pgsin_a; 5309 VM_CNT_INC(v_vnodein); 5310 VM_CNT_ADD(v_vnodepgsin, pgsin); 5311 5312 br_flags = (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) 5313 != 0) ? GB_UNMAPPED : 0; 5314 again: 5315 for (i = 0; i < count; i++) { 5316 if (ma[i] != bogus_page) 5317 vm_page_busy_downgrade(ma[i]); 5318 } 5319 5320 lbnp = -1; 5321 for (i = 0; i < count; i++) { 5322 m = ma[i]; 5323 if (m == bogus_page) 5324 continue; 5325 5326 /* 5327 * Pages are shared busy and the object lock is not 5328 * owned, which together allow for the pages' 5329 * invalidation. The racy test for validity avoids 5330 * useless creation of the buffer for the most typical 5331 * case when invalidation is not used in redo or for 5332 * parallel read. The shared->excl upgrade loop at 5333 * the end of the function catches the race in a 5334 * reliable way (protected by the object lock). 5335 */ 5336 if (vm_page_all_valid(m)) 5337 continue; 5338 5339 poff = IDX_TO_OFF(m->pindex); 5340 poffe = MIN(poff + PAGE_SIZE, object->un_pager.vnp.vnp_size); 5341 for (; poff < poffe; poff += bsize) { 5342 lbn = get_lblkno(vp, poff); 5343 if (lbn == lbnp) 5344 goto next_page; 5345 lbnp = lbn; 5346 5347 error = get_blksize(vp, lbn, &bsize); 5348 if (error == 0) 5349 error = bread_gb(vp, lbn, bsize, 5350 curthread->td_ucred, br_flags, &bp); 5351 if (error != 0) 5352 goto end_pages; 5353 if (bp->b_rcred == curthread->td_ucred) { 5354 crfree(bp->b_rcred); 5355 bp->b_rcred = NOCRED; 5356 } 5357 if (LIST_EMPTY(&bp->b_dep)) { 5358 /* 5359 * Invalidation clears m->valid, but 5360 * may leave B_CACHE flag if the 5361 * buffer existed at the invalidation 5362 * time. In this case, recycle the 5363 * buffer to do real read on next 5364 * bread() after redo. 5365 * 5366 * Otherwise B_RELBUF is not strictly 5367 * necessary, enable to reduce buf 5368 * cache pressure. 5369 */ 5370 if (buf_pager_relbuf || 5371 !vm_page_all_valid(m)) 5372 bp->b_flags |= B_RELBUF; 5373 5374 bp->b_flags &= ~B_NOCACHE; 5375 brelse(bp); 5376 } else { 5377 bqrelse(bp); 5378 } 5379 } 5380 KASSERT(1 /* racy, enable for debugging */ || 5381 vm_page_all_valid(m) || i == count - 1, 5382 ("buf %d %p invalid", i, m)); 5383 if (i == count - 1 && lpart) { 5384 if (!vm_page_none_valid(m) && 5385 !vm_page_all_valid(m)) 5386 vm_page_zero_invalid(m, TRUE); 5387 } 5388 next_page:; 5389 } 5390 end_pages: 5391 5392 redo = false; 5393 for (i = 0; i < count; i++) { 5394 if (ma[i] == bogus_page) 5395 continue; 5396 if (vm_page_busy_tryupgrade(ma[i]) == 0) { 5397 vm_page_sunbusy(ma[i]); 5398 ma[i] = vm_page_grab_unlocked(object, ma[i]->pindex, 5399 VM_ALLOC_NORMAL); 5400 } 5401 5402 /* 5403 * Since the pages were only sbusy while neither the 5404 * buffer nor the object lock was held by us, or 5405 * reallocated while vm_page_grab() slept for busy 5406 * relinguish, they could have been invalidated. 5407 * Recheck the valid bits and re-read as needed. 5408 * 5409 * Note that the last page is made fully valid in the 5410 * read loop, and partial validity for the page at 5411 * index count - 1 could mean that the page was 5412 * invalidated or removed, so we must restart for 5413 * safety as well. 5414 */ 5415 if (!vm_page_all_valid(ma[i])) 5416 redo = true; 5417 } 5418 if (redo && error == 0) 5419 goto again; 5420 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 5421 } 5422 5423 #include "opt_ddb.h" 5424 #ifdef DDB 5425 #include <ddb/ddb.h> 5426 5427 /* DDB command to show buffer data */ 5428 DB_SHOW_COMMAND(buffer, db_show_buffer) 5429 { 5430 /* get args */ 5431 struct buf *bp = (struct buf *)addr; 5432 #ifdef FULL_BUF_TRACKING 5433 uint32_t i, j; 5434 #endif 5435 5436 if (!have_addr) { 5437 db_printf("usage: show buffer <addr>\n"); 5438 return; 5439 } 5440 5441 db_printf("buf at %p\n", bp); 5442 db_printf("b_flags = 0x%b, b_xflags=0x%b\n", 5443 (u_int)bp->b_flags, PRINT_BUF_FLAGS, 5444 (u_int)bp->b_xflags, PRINT_BUF_XFLAGS); 5445 db_printf("b_vflags=0x%b b_ioflags0x%b\n", 5446 (u_int)bp->b_vflags, PRINT_BUF_VFLAGS, 5447 (u_int)bp->b_ioflags, PRINT_BIO_FLAGS); 5448 db_printf( 5449 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n" 5450 "b_bufobj = (%p), b_data = %p\n, b_blkno = %jd, b_lblkno = %jd, " 5451 "b_vp = %p, b_dep = %p\n", 5452 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 5453 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno, 5454 (intmax_t)bp->b_lblkno, bp->b_vp, bp->b_dep.lh_first); 5455 db_printf("b_kvabase = %p, b_kvasize = %d\n", 5456 bp->b_kvabase, bp->b_kvasize); 5457 if (bp->b_npages) { 5458 int i; 5459 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 5460 for (i = 0; i < bp->b_npages; i++) { 5461 vm_page_t m; 5462 m = bp->b_pages[i]; 5463 if (m != NULL) 5464 db_printf("(%p, 0x%lx, 0x%lx)", m->object, 5465 (u_long)m->pindex, 5466 (u_long)VM_PAGE_TO_PHYS(m)); 5467 else 5468 db_printf("( ??? )"); 5469 if ((i + 1) < bp->b_npages) 5470 db_printf(","); 5471 } 5472 db_printf("\n"); 5473 } 5474 BUF_LOCKPRINTINFO(bp); 5475 #if defined(FULL_BUF_TRACKING) 5476 db_printf("b_io_tracking: b_io_tcnt = %u\n", bp->b_io_tcnt); 5477 5478 i = bp->b_io_tcnt % BUF_TRACKING_SIZE; 5479 for (j = 1; j <= BUF_TRACKING_SIZE; j++) { 5480 if (bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)] == NULL) 5481 continue; 5482 db_printf(" %2u: %s\n", j, 5483 bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)]); 5484 } 5485 #elif defined(BUF_TRACKING) 5486 db_printf("b_io_tracking: %s\n", bp->b_io_tracking); 5487 #endif 5488 db_printf(" "); 5489 } 5490 5491 DB_SHOW_COMMAND_FLAGS(bufqueues, bufqueues, DB_CMD_MEMSAFE) 5492 { 5493 struct bufdomain *bd; 5494 struct buf *bp; 5495 long total; 5496 int i, j, cnt; 5497 5498 db_printf("bqempty: %d\n", bqempty.bq_len); 5499 5500 for (i = 0; i < buf_domains; i++) { 5501 bd = &bdomain[i]; 5502 db_printf("Buf domain %d\n", i); 5503 db_printf("\tfreebufs\t%d\n", bd->bd_freebuffers); 5504 db_printf("\tlofreebufs\t%d\n", bd->bd_lofreebuffers); 5505 db_printf("\thifreebufs\t%d\n", bd->bd_hifreebuffers); 5506 db_printf("\n"); 5507 db_printf("\tbufspace\t%ld\n", bd->bd_bufspace); 5508 db_printf("\tmaxbufspace\t%ld\n", bd->bd_maxbufspace); 5509 db_printf("\thibufspace\t%ld\n", bd->bd_hibufspace); 5510 db_printf("\tlobufspace\t%ld\n", bd->bd_lobufspace); 5511 db_printf("\tbufspacethresh\t%ld\n", bd->bd_bufspacethresh); 5512 db_printf("\n"); 5513 db_printf("\tnumdirtybuffers\t%d\n", bd->bd_numdirtybuffers); 5514 db_printf("\tlodirtybuffers\t%d\n", bd->bd_lodirtybuffers); 5515 db_printf("\thidirtybuffers\t%d\n", bd->bd_hidirtybuffers); 5516 db_printf("\tdirtybufthresh\t%d\n", bd->bd_dirtybufthresh); 5517 db_printf("\n"); 5518 total = 0; 5519 TAILQ_FOREACH(bp, &bd->bd_cleanq->bq_queue, b_freelist) 5520 total += bp->b_bufsize; 5521 db_printf("\tcleanq count\t%d (%ld)\n", 5522 bd->bd_cleanq->bq_len, total); 5523 total = 0; 5524 TAILQ_FOREACH(bp, &bd->bd_dirtyq.bq_queue, b_freelist) 5525 total += bp->b_bufsize; 5526 db_printf("\tdirtyq count\t%d (%ld)\n", 5527 bd->bd_dirtyq.bq_len, total); 5528 db_printf("\twakeup\t\t%d\n", bd->bd_wanted); 5529 db_printf("\tlim\t\t%d\n", bd->bd_lim); 5530 db_printf("\tCPU "); 5531 for (j = 0; j <= mp_maxid; j++) 5532 db_printf("%d, ", bd->bd_subq[j].bq_len); 5533 db_printf("\n"); 5534 cnt = 0; 5535 total = 0; 5536 for (j = 0; j < nbuf; j++) { 5537 bp = nbufp(j); 5538 if (bp->b_domain == i && BUF_ISLOCKED(bp)) { 5539 cnt++; 5540 total += bp->b_bufsize; 5541 } 5542 } 5543 db_printf("\tLocked buffers: %d space %ld\n", cnt, total); 5544 cnt = 0; 5545 total = 0; 5546 for (j = 0; j < nbuf; j++) { 5547 bp = nbufp(j); 5548 if (bp->b_domain == i) { 5549 cnt++; 5550 total += bp->b_bufsize; 5551 } 5552 } 5553 db_printf("\tTotal buffers: %d space %ld\n", cnt, total); 5554 } 5555 } 5556 5557 DB_SHOW_COMMAND_FLAGS(lockedbufs, lockedbufs, DB_CMD_MEMSAFE) 5558 { 5559 struct buf *bp; 5560 int i; 5561 5562 for (i = 0; i < nbuf; i++) { 5563 bp = nbufp(i); 5564 if (BUF_ISLOCKED(bp)) { 5565 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5566 db_printf("\n"); 5567 if (db_pager_quit) 5568 break; 5569 } 5570 } 5571 } 5572 5573 DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs) 5574 { 5575 struct vnode *vp; 5576 struct buf *bp; 5577 5578 if (!have_addr) { 5579 db_printf("usage: show vnodebufs <addr>\n"); 5580 return; 5581 } 5582 vp = (struct vnode *)addr; 5583 db_printf("Clean buffers:\n"); 5584 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) { 5585 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5586 db_printf("\n"); 5587 } 5588 db_printf("Dirty buffers:\n"); 5589 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) { 5590 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5591 db_printf("\n"); 5592 } 5593 } 5594 5595 DB_COMMAND_FLAGS(countfreebufs, db_coundfreebufs, DB_CMD_MEMSAFE) 5596 { 5597 struct buf *bp; 5598 int i, used = 0, nfree = 0; 5599 5600 if (have_addr) { 5601 db_printf("usage: countfreebufs\n"); 5602 return; 5603 } 5604 5605 for (i = 0; i < nbuf; i++) { 5606 bp = nbufp(i); 5607 if (bp->b_qindex == QUEUE_EMPTY) 5608 nfree++; 5609 else 5610 used++; 5611 } 5612 5613 db_printf("Counted %d free, %d used (%d tot)\n", nfree, used, 5614 nfree + used); 5615 db_printf("numfreebuffers is %d\n", numfreebuffers); 5616 } 5617 #endif /* DDB */ 5618