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/memdesc.h> 67 #include <sys/mount.h> 68 #include <sys/mutex.h> 69 #include <sys/kernel.h> 70 #include <sys/kthread.h> 71 #include <sys/pctrie.h> 72 #include <sys/proc.h> 73 #include <sys/racct.h> 74 #include <sys/refcount.h> 75 #include <sys/resourcevar.h> 76 #include <sys/rwlock.h> 77 #include <sys/sched.h> 78 #include <sys/smp.h> 79 #include <sys/sysctl.h> 80 #include <sys/syscallsubr.h> 81 #include <sys/vmem.h> 82 #include <sys/vmmeter.h> 83 #include <sys/vnode.h> 84 #include <sys/watchdog.h> 85 #include <geom/geom.h> 86 #include <vm/vm.h> 87 #include <vm/vm_param.h> 88 #include <vm/vm_kern.h> 89 #include <vm/vm_object.h> 90 #include <vm/vm_page.h> 91 #include <vm/vm_pageout.h> 92 #include <vm/vm_pager.h> 93 #include <vm/vm_extern.h> 94 #include <vm/vm_map.h> 95 #include <vm/swap_pager.h> 96 97 static MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer"); 98 99 struct bio_ops bioops; /* I/O operation notification */ 100 101 struct buf_ops buf_ops_bio = { 102 .bop_name = "buf_ops_bio", 103 .bop_write = bufwrite, 104 .bop_strategy = bufstrategy, 105 .bop_sync = bufsync, 106 .bop_bdflush = bufbdflush, 107 }; 108 109 struct bufqueue { 110 struct mtx_padalign bq_lock; 111 TAILQ_HEAD(, buf) bq_queue; 112 uint8_t bq_index; 113 uint16_t bq_subqueue; 114 int bq_len; 115 } __aligned(CACHE_LINE_SIZE); 116 117 #define BQ_LOCKPTR(bq) (&(bq)->bq_lock) 118 #define BQ_LOCK(bq) mtx_lock(BQ_LOCKPTR((bq))) 119 #define BQ_UNLOCK(bq) mtx_unlock(BQ_LOCKPTR((bq))) 120 #define BQ_ASSERT_LOCKED(bq) mtx_assert(BQ_LOCKPTR((bq)), MA_OWNED) 121 122 struct bufdomain { 123 struct bufqueue *bd_subq; 124 struct bufqueue bd_dirtyq; 125 struct bufqueue *bd_cleanq; 126 struct mtx_padalign bd_run_lock; 127 /* Constants */ 128 long bd_maxbufspace; 129 long bd_hibufspace; 130 long bd_lobufspace; 131 long bd_bufspacethresh; 132 int bd_hifreebuffers; 133 int bd_lofreebuffers; 134 int bd_hidirtybuffers; 135 int bd_lodirtybuffers; 136 int bd_dirtybufthresh; 137 int bd_lim; 138 /* atomics */ 139 int bd_wanted; 140 bool bd_shutdown; 141 int __aligned(CACHE_LINE_SIZE) bd_numdirtybuffers; 142 int __aligned(CACHE_LINE_SIZE) bd_running; 143 long __aligned(CACHE_LINE_SIZE) bd_bufspace; 144 int __aligned(CACHE_LINE_SIZE) bd_freebuffers; 145 } __aligned(CACHE_LINE_SIZE); 146 147 #define BD_LOCKPTR(bd) (&(bd)->bd_cleanq->bq_lock) 148 #define BD_LOCK(bd) mtx_lock(BD_LOCKPTR((bd))) 149 #define BD_UNLOCK(bd) mtx_unlock(BD_LOCKPTR((bd))) 150 #define BD_ASSERT_LOCKED(bd) mtx_assert(BD_LOCKPTR((bd)), MA_OWNED) 151 #define BD_RUN_LOCKPTR(bd) (&(bd)->bd_run_lock) 152 #define BD_RUN_LOCK(bd) mtx_lock(BD_RUN_LOCKPTR((bd))) 153 #define BD_RUN_UNLOCK(bd) mtx_unlock(BD_RUN_LOCKPTR((bd))) 154 #define BD_DOMAIN(bd) (bd - bdomain) 155 156 static char *buf; /* buffer header pool */ 157 static struct buf * 158 nbufp(unsigned i) 159 { 160 return ((struct buf *)(buf + (sizeof(struct buf) + 161 sizeof(vm_page_t) * atop(maxbcachebuf)) * i)); 162 } 163 164 caddr_t __read_mostly unmapped_buf; 165 166 /* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.c */ 167 struct proc *bufdaemonproc; 168 169 static void vm_hold_free_pages(struct buf *bp, int newbsize); 170 static void vm_hold_load_pages(struct buf *bp, vm_offset_t from, 171 vm_offset_t to); 172 static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m); 173 static void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, 174 vm_page_t m); 175 static void vfs_clean_pages_dirty_buf(struct buf *bp); 176 static void vfs_setdirty_range(struct buf *bp); 177 static void vfs_vmio_invalidate(struct buf *bp); 178 static void vfs_vmio_truncate(struct buf *bp, int npages); 179 static void vfs_vmio_extend(struct buf *bp, int npages, int size); 180 static int vfs_bio_clcheck(struct vnode *vp, int size, 181 daddr_t lblkno, daddr_t blkno); 182 static void breada(struct vnode *, daddr_t *, int *, int, struct ucred *, int, 183 void (*)(struct buf *)); 184 static int buf_flush(struct vnode *vp, struct bufdomain *, int); 185 static int flushbufqueues(struct vnode *, struct bufdomain *, int, int); 186 static void buf_daemon(void); 187 static __inline void bd_wakeup(void); 188 static int sysctl_runningspace(SYSCTL_HANDLER_ARGS); 189 static void bufkva_reclaim(vmem_t *, int); 190 static void bufkva_free(struct buf *); 191 static int buf_import(void *, void **, int, int, int); 192 static void buf_release(void *, void **, int); 193 static void maxbcachebuf_adjust(void); 194 static inline struct bufdomain *bufdomain(struct buf *); 195 static void bq_remove(struct bufqueue *bq, struct buf *bp); 196 static void bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock); 197 static int buf_recycle(struct bufdomain *, bool kva); 198 static void bq_init(struct bufqueue *bq, int qindex, int cpu, 199 const char *lockname); 200 static void bd_init(struct bufdomain *bd); 201 static int bd_flushall(struct bufdomain *bd); 202 static int sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS); 203 static int sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS); 204 205 static int sysctl_bufspace(SYSCTL_HANDLER_ARGS); 206 int vmiodirenable = TRUE; 207 SYSCTL_INT(_vfs, OID_AUTO, vmiodirenable, CTLFLAG_RW, &vmiodirenable, 0, 208 "Use the VM system for directory writes"); 209 long runningbufspace; 210 SYSCTL_LONG(_vfs, OID_AUTO, runningbufspace, CTLFLAG_RD, &runningbufspace, 0, 211 "Amount of presently outstanding async buffer io"); 212 SYSCTL_PROC(_vfs, OID_AUTO, bufspace, CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RD, 213 NULL, 0, sysctl_bufspace, "L", "Physical memory used for buffers"); 214 static counter_u64_t bufkvaspace; 215 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufkvaspace, CTLFLAG_RD, &bufkvaspace, 216 "Kernel virtual memory used for buffers"); 217 static long maxbufspace; 218 SYSCTL_PROC(_vfs, OID_AUTO, maxbufspace, 219 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &maxbufspace, 220 __offsetof(struct bufdomain, bd_maxbufspace), sysctl_bufdomain_long, "L", 221 "Maximum allowed value of bufspace (including metadata)"); 222 static long bufmallocspace; 223 SYSCTL_LONG(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0, 224 "Amount of malloced memory for buffers"); 225 static long maxbufmallocspace; 226 SYSCTL_LONG(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace, 227 0, "Maximum amount of malloced memory for buffers"); 228 static long lobufspace; 229 SYSCTL_PROC(_vfs, OID_AUTO, lobufspace, 230 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &lobufspace, 231 __offsetof(struct bufdomain, bd_lobufspace), sysctl_bufdomain_long, "L", 232 "Minimum amount of buffers we want to have"); 233 long hibufspace; 234 SYSCTL_PROC(_vfs, OID_AUTO, hibufspace, 235 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &hibufspace, 236 __offsetof(struct bufdomain, bd_hibufspace), sysctl_bufdomain_long, "L", 237 "Maximum allowed value of bufspace (excluding metadata)"); 238 long bufspacethresh; 239 SYSCTL_PROC(_vfs, OID_AUTO, bufspacethresh, 240 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &bufspacethresh, 241 __offsetof(struct bufdomain, bd_bufspacethresh), sysctl_bufdomain_long, "L", 242 "Bufspace consumed before waking the daemon to free some"); 243 static counter_u64_t buffreekvacnt; 244 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, buffreekvacnt, CTLFLAG_RW, &buffreekvacnt, 245 "Number of times we have freed the KVA space from some buffer"); 246 static counter_u64_t bufdefragcnt; 247 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufdefragcnt, CTLFLAG_RW, &bufdefragcnt, 248 "Number of times we have had to repeat buffer allocation to defragment"); 249 static long lorunningspace; 250 SYSCTL_PROC(_vfs, OID_AUTO, lorunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 251 CTLFLAG_RW, &lorunningspace, 0, sysctl_runningspace, "L", 252 "Minimum preferred space used for in-progress I/O"); 253 static long hirunningspace; 254 SYSCTL_PROC(_vfs, OID_AUTO, hirunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 255 CTLFLAG_RW, &hirunningspace, 0, sysctl_runningspace, "L", 256 "Maximum amount of space to use for in-progress I/O"); 257 int dirtybufferflushes; 258 SYSCTL_INT(_vfs, OID_AUTO, dirtybufferflushes, CTLFLAG_RW, &dirtybufferflushes, 259 0, "Number of bdwrite to bawrite conversions to limit dirty buffers"); 260 int bdwriteskip; 261 SYSCTL_INT(_vfs, OID_AUTO, bdwriteskip, CTLFLAG_RW, &bdwriteskip, 262 0, "Number of buffers supplied to bdwrite with snapshot deadlock risk"); 263 int altbufferflushes; 264 SYSCTL_INT(_vfs, OID_AUTO, altbufferflushes, CTLFLAG_RW | CTLFLAG_STATS, 265 &altbufferflushes, 0, "Number of fsync flushes to limit dirty buffers"); 266 static int recursiveflushes; 267 SYSCTL_INT(_vfs, OID_AUTO, recursiveflushes, CTLFLAG_RW | CTLFLAG_STATS, 268 &recursiveflushes, 0, "Number of flushes skipped due to being recursive"); 269 static int sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS); 270 SYSCTL_PROC(_vfs, OID_AUTO, numdirtybuffers, 271 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RD, NULL, 0, sysctl_numdirtybuffers, "I", 272 "Number of buffers that are dirty (has unwritten changes) at the moment"); 273 static int lodirtybuffers; 274 SYSCTL_PROC(_vfs, OID_AUTO, lodirtybuffers, 275 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lodirtybuffers, 276 __offsetof(struct bufdomain, bd_lodirtybuffers), sysctl_bufdomain_int, "I", 277 "How many buffers we want to have free before bufdaemon can sleep"); 278 static int hidirtybuffers; 279 SYSCTL_PROC(_vfs, OID_AUTO, hidirtybuffers, 280 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hidirtybuffers, 281 __offsetof(struct bufdomain, bd_hidirtybuffers), sysctl_bufdomain_int, "I", 282 "When the number of dirty buffers is considered severe"); 283 int dirtybufthresh; 284 SYSCTL_PROC(_vfs, OID_AUTO, dirtybufthresh, 285 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &dirtybufthresh, 286 __offsetof(struct bufdomain, bd_dirtybufthresh), sysctl_bufdomain_int, "I", 287 "Number of bdwrite to bawrite conversions to clear dirty buffers"); 288 static int numfreebuffers; 289 SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0, 290 "Number of free buffers"); 291 static int lofreebuffers; 292 SYSCTL_PROC(_vfs, OID_AUTO, lofreebuffers, 293 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lofreebuffers, 294 __offsetof(struct bufdomain, bd_lofreebuffers), sysctl_bufdomain_int, "I", 295 "Target number of free buffers"); 296 static int hifreebuffers; 297 SYSCTL_PROC(_vfs, OID_AUTO, hifreebuffers, 298 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hifreebuffers, 299 __offsetof(struct bufdomain, bd_hifreebuffers), sysctl_bufdomain_int, "I", 300 "Threshold for clean buffer recycling"); 301 static counter_u64_t getnewbufcalls; 302 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufcalls, CTLFLAG_RD, 303 &getnewbufcalls, "Number of calls to getnewbuf"); 304 static counter_u64_t getnewbufrestarts; 305 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufrestarts, CTLFLAG_RD, 306 &getnewbufrestarts, 307 "Number of times getnewbuf has had to restart a buffer acquisition"); 308 static counter_u64_t mappingrestarts; 309 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, mappingrestarts, CTLFLAG_RD, 310 &mappingrestarts, 311 "Number of times getblk has had to restart a buffer mapping for " 312 "unmapped buffer"); 313 static counter_u64_t numbufallocfails; 314 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, numbufallocfails, CTLFLAG_RW, 315 &numbufallocfails, "Number of times buffer allocations failed"); 316 static int flushbufqtarget = 100; 317 SYSCTL_INT(_vfs, OID_AUTO, flushbufqtarget, CTLFLAG_RW, &flushbufqtarget, 0, 318 "Amount of work to do in flushbufqueues when helping bufdaemon"); 319 static counter_u64_t notbufdflushes; 320 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, notbufdflushes, CTLFLAG_RD, ¬bufdflushes, 321 "Number of dirty buffer flushes done by the bufdaemon helpers"); 322 static long barrierwrites; 323 SYSCTL_LONG(_vfs, OID_AUTO, barrierwrites, CTLFLAG_RW | CTLFLAG_STATS, 324 &barrierwrites, 0, "Number of barrier writes"); 325 SYSCTL_INT(_vfs, OID_AUTO, unmapped_buf_allowed, CTLFLAG_RD, 326 &unmapped_buf_allowed, 0, 327 "Permit the use of the unmapped i/o"); 328 int maxbcachebuf = MAXBCACHEBUF; 329 SYSCTL_INT(_vfs, OID_AUTO, maxbcachebuf, CTLFLAG_RDTUN, &maxbcachebuf, 0, 330 "Maximum size of a buffer cache block"); 331 332 /* 333 * This lock synchronizes access to bd_request. 334 */ 335 static struct mtx_padalign __exclusive_cache_line bdlock; 336 337 /* 338 * This lock protects the runningbufreq and synchronizes runningbufwakeup and 339 * waitrunningbufspace(). 340 */ 341 static struct mtx_padalign __exclusive_cache_line rbreqlock; 342 343 /* 344 * Lock that protects bdirtywait. 345 */ 346 static struct mtx_padalign __exclusive_cache_line bdirtylock; 347 348 /* 349 * bufdaemon shutdown request and sleep channel. 350 */ 351 static bool bd_shutdown; 352 353 /* 354 * Wakeup point for bufdaemon, as well as indicator of whether it is already 355 * active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it 356 * is idling. 357 */ 358 static int bd_request; 359 360 /* 361 * Request for the buf daemon to write more buffers than is indicated by 362 * lodirtybuf. This may be necessary to push out excess dependencies or 363 * defragment the address space where a simple count of the number of dirty 364 * buffers is insufficient to characterize the demand for flushing them. 365 */ 366 static int bd_speedupreq; 367 368 /* 369 * Synchronization (sleep/wakeup) variable for active buffer space requests. 370 * Set when wait starts, cleared prior to wakeup(). 371 * Used in runningbufwakeup() and waitrunningbufspace(). 372 */ 373 static int runningbufreq; 374 375 /* 376 * Synchronization for bwillwrite() waiters. 377 */ 378 static int bdirtywait; 379 380 /* 381 * Definitions for the buffer free lists. 382 */ 383 #define QUEUE_NONE 0 /* on no queue */ 384 #define QUEUE_EMPTY 1 /* empty buffer headers */ 385 #define QUEUE_DIRTY 2 /* B_DELWRI buffers */ 386 #define QUEUE_CLEAN 3 /* non-B_DELWRI buffers */ 387 #define QUEUE_SENTINEL 4 /* not an queue index, but mark for sentinel */ 388 389 /* Maximum number of buffer domains. */ 390 #define BUF_DOMAINS 8 391 392 struct bufdomainset bdlodirty; /* Domains > lodirty */ 393 struct bufdomainset bdhidirty; /* Domains > hidirty */ 394 395 /* Configured number of clean queues. */ 396 static int __read_mostly buf_domains; 397 398 BITSET_DEFINE(bufdomainset, BUF_DOMAINS); 399 struct bufdomain __exclusive_cache_line bdomain[BUF_DOMAINS]; 400 struct bufqueue __exclusive_cache_line bqempty; 401 402 /* 403 * per-cpu empty buffer cache. 404 */ 405 uma_zone_t buf_zone; 406 407 static int 408 sysctl_runningspace(SYSCTL_HANDLER_ARGS) 409 { 410 long value; 411 int error; 412 413 value = *(long *)arg1; 414 error = sysctl_handle_long(oidp, &value, 0, req); 415 if (error != 0 || req->newptr == NULL) 416 return (error); 417 mtx_lock(&rbreqlock); 418 if (arg1 == &hirunningspace) { 419 if (value < lorunningspace) 420 error = EINVAL; 421 else 422 hirunningspace = value; 423 } else { 424 KASSERT(arg1 == &lorunningspace, 425 ("%s: unknown arg1", __func__)); 426 if (value > hirunningspace) 427 error = EINVAL; 428 else 429 lorunningspace = value; 430 } 431 mtx_unlock(&rbreqlock); 432 return (error); 433 } 434 435 static int 436 sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS) 437 { 438 int error; 439 int value; 440 int i; 441 442 value = *(int *)arg1; 443 error = sysctl_handle_int(oidp, &value, 0, req); 444 if (error != 0 || req->newptr == NULL) 445 return (error); 446 *(int *)arg1 = value; 447 for (i = 0; i < buf_domains; i++) 448 *(int *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 449 value / buf_domains; 450 451 return (error); 452 } 453 454 static int 455 sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS) 456 { 457 long value; 458 int error; 459 int i; 460 461 value = *(long *)arg1; 462 error = sysctl_handle_long(oidp, &value, 0, req); 463 if (error != 0 || req->newptr == NULL) 464 return (error); 465 *(long *)arg1 = value; 466 for (i = 0; i < buf_domains; i++) 467 *(long *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 468 value / buf_domains; 469 470 return (error); 471 } 472 473 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 474 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 475 static int 476 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 477 { 478 long lvalue; 479 int ivalue; 480 int i; 481 482 lvalue = 0; 483 for (i = 0; i < buf_domains; i++) 484 lvalue += bdomain[i].bd_bufspace; 485 if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long)) 486 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 487 if (lvalue > INT_MAX) 488 /* On overflow, still write out a long to trigger ENOMEM. */ 489 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 490 ivalue = lvalue; 491 return (sysctl_handle_int(oidp, &ivalue, 0, req)); 492 } 493 #else 494 static int 495 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 496 { 497 long lvalue; 498 int i; 499 500 lvalue = 0; 501 for (i = 0; i < buf_domains; i++) 502 lvalue += bdomain[i].bd_bufspace; 503 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 504 } 505 #endif 506 507 static int 508 sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS) 509 { 510 int value; 511 int i; 512 513 value = 0; 514 for (i = 0; i < buf_domains; i++) 515 value += bdomain[i].bd_numdirtybuffers; 516 return (sysctl_handle_int(oidp, &value, 0, req)); 517 } 518 519 /* 520 * bdirtywakeup: 521 * 522 * Wakeup any bwillwrite() waiters. 523 */ 524 static void 525 bdirtywakeup(void) 526 { 527 mtx_lock(&bdirtylock); 528 if (bdirtywait) { 529 bdirtywait = 0; 530 wakeup(&bdirtywait); 531 } 532 mtx_unlock(&bdirtylock); 533 } 534 535 /* 536 * bd_clear: 537 * 538 * Clear a domain from the appropriate bitsets when dirtybuffers 539 * is decremented. 540 */ 541 static void 542 bd_clear(struct bufdomain *bd) 543 { 544 545 mtx_lock(&bdirtylock); 546 if (bd->bd_numdirtybuffers <= bd->bd_lodirtybuffers) 547 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 548 if (bd->bd_numdirtybuffers <= bd->bd_hidirtybuffers) 549 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 550 mtx_unlock(&bdirtylock); 551 } 552 553 /* 554 * bd_set: 555 * 556 * Set a domain in the appropriate bitsets when dirtybuffers 557 * is incremented. 558 */ 559 static void 560 bd_set(struct bufdomain *bd) 561 { 562 563 mtx_lock(&bdirtylock); 564 if (bd->bd_numdirtybuffers > bd->bd_lodirtybuffers) 565 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 566 if (bd->bd_numdirtybuffers > bd->bd_hidirtybuffers) 567 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 568 mtx_unlock(&bdirtylock); 569 } 570 571 /* 572 * bdirtysub: 573 * 574 * Decrement the numdirtybuffers count by one and wakeup any 575 * threads blocked in bwillwrite(). 576 */ 577 static void 578 bdirtysub(struct buf *bp) 579 { 580 struct bufdomain *bd; 581 int num; 582 583 bd = bufdomain(bp); 584 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, -1); 585 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 586 bdirtywakeup(); 587 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 588 bd_clear(bd); 589 } 590 591 /* 592 * bdirtyadd: 593 * 594 * Increment the numdirtybuffers count by one and wakeup the buf 595 * daemon if needed. 596 */ 597 static void 598 bdirtyadd(struct buf *bp) 599 { 600 struct bufdomain *bd; 601 int num; 602 603 /* 604 * Only do the wakeup once as we cross the boundary. The 605 * buf daemon will keep running until the condition clears. 606 */ 607 bd = bufdomain(bp); 608 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, 1); 609 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 610 bd_wakeup(); 611 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 612 bd_set(bd); 613 } 614 615 /* 616 * bufspace_daemon_wakeup: 617 * 618 * Wakeup the daemons responsible for freeing clean bufs. 619 */ 620 static void 621 bufspace_daemon_wakeup(struct bufdomain *bd) 622 { 623 624 /* 625 * avoid the lock if the daemon is running. 626 */ 627 if (atomic_fetchadd_int(&bd->bd_running, 1) == 0) { 628 BD_RUN_LOCK(bd); 629 atomic_store_int(&bd->bd_running, 1); 630 wakeup(&bd->bd_running); 631 BD_RUN_UNLOCK(bd); 632 } 633 } 634 635 /* 636 * bufspace_adjust: 637 * 638 * Adjust the reported bufspace for a KVA managed buffer, possibly 639 * waking any waiters. 640 */ 641 static void 642 bufspace_adjust(struct buf *bp, int bufsize) 643 { 644 struct bufdomain *bd; 645 long space; 646 int diff; 647 648 KASSERT((bp->b_flags & B_MALLOC) == 0, 649 ("bufspace_adjust: malloc buf %p", bp)); 650 bd = bufdomain(bp); 651 diff = bufsize - bp->b_bufsize; 652 if (diff < 0) { 653 atomic_subtract_long(&bd->bd_bufspace, -diff); 654 } else if (diff > 0) { 655 space = atomic_fetchadd_long(&bd->bd_bufspace, diff); 656 /* Wake up the daemon on the transition. */ 657 if (space < bd->bd_bufspacethresh && 658 space + diff >= bd->bd_bufspacethresh) 659 bufspace_daemon_wakeup(bd); 660 } 661 bp->b_bufsize = bufsize; 662 } 663 664 /* 665 * bufspace_reserve: 666 * 667 * Reserve bufspace before calling allocbuf(). metadata has a 668 * different space limit than data. 669 */ 670 static int 671 bufspace_reserve(struct bufdomain *bd, int size, bool metadata) 672 { 673 long limit, new; 674 long space; 675 676 if (metadata) 677 limit = bd->bd_maxbufspace; 678 else 679 limit = bd->bd_hibufspace; 680 space = atomic_fetchadd_long(&bd->bd_bufspace, size); 681 new = space + size; 682 if (new > limit) { 683 atomic_subtract_long(&bd->bd_bufspace, size); 684 return (ENOSPC); 685 } 686 687 /* Wake up the daemon on the transition. */ 688 if (space < bd->bd_bufspacethresh && new >= bd->bd_bufspacethresh) 689 bufspace_daemon_wakeup(bd); 690 691 return (0); 692 } 693 694 /* 695 * bufspace_release: 696 * 697 * Release reserved bufspace after bufspace_adjust() has consumed it. 698 */ 699 static void 700 bufspace_release(struct bufdomain *bd, int size) 701 { 702 703 atomic_subtract_long(&bd->bd_bufspace, size); 704 } 705 706 /* 707 * bufspace_wait: 708 * 709 * Wait for bufspace, acting as the buf daemon if a locked vnode is 710 * supplied. bd_wanted must be set prior to polling for space. The 711 * operation must be re-tried on return. 712 */ 713 static void 714 bufspace_wait(struct bufdomain *bd, struct vnode *vp, int gbflags, 715 int slpflag, int slptimeo) 716 { 717 struct thread *td; 718 int error, fl, norunbuf; 719 720 if ((gbflags & GB_NOWAIT_BD) != 0) 721 return; 722 723 td = curthread; 724 BD_LOCK(bd); 725 while (bd->bd_wanted) { 726 if (vp != NULL && vp->v_type != VCHR && 727 (td->td_pflags & TDP_BUFNEED) == 0) { 728 BD_UNLOCK(bd); 729 /* 730 * getblk() is called with a vnode locked, and 731 * some majority of the dirty buffers may as 732 * well belong to the vnode. Flushing the 733 * buffers there would make a progress that 734 * cannot be achieved by the buf_daemon, that 735 * cannot lock the vnode. 736 */ 737 norunbuf = ~(TDP_BUFNEED | TDP_NORUNNINGBUF) | 738 (td->td_pflags & TDP_NORUNNINGBUF); 739 740 /* 741 * Play bufdaemon. The getnewbuf() function 742 * may be called while the thread owns lock 743 * for another dirty buffer for the same 744 * vnode, which makes it impossible to use 745 * VOP_FSYNC() there, due to the buffer lock 746 * recursion. 747 */ 748 td->td_pflags |= TDP_BUFNEED | TDP_NORUNNINGBUF; 749 fl = buf_flush(vp, bd, flushbufqtarget); 750 td->td_pflags &= norunbuf; 751 BD_LOCK(bd); 752 if (fl != 0) 753 continue; 754 if (bd->bd_wanted == 0) 755 break; 756 } 757 error = msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 758 (PRIBIO + 4) | slpflag, "newbuf", slptimeo); 759 if (error != 0) 760 break; 761 } 762 BD_UNLOCK(bd); 763 } 764 765 static void 766 bufspace_daemon_shutdown(void *arg, int howto __unused) 767 { 768 struct bufdomain *bd = arg; 769 int error; 770 771 if (KERNEL_PANICKED()) 772 return; 773 774 BD_RUN_LOCK(bd); 775 bd->bd_shutdown = true; 776 wakeup(&bd->bd_running); 777 error = msleep(&bd->bd_shutdown, BD_RUN_LOCKPTR(bd), 0, 778 "bufspace_shutdown", 60 * hz); 779 BD_RUN_UNLOCK(bd); 780 if (error != 0) 781 printf("bufspacedaemon wait error: %d\n", error); 782 } 783 784 /* 785 * bufspace_daemon: 786 * 787 * buffer space management daemon. Tries to maintain some marginal 788 * amount of free buffer space so that requesting processes neither 789 * block nor work to reclaim buffers. 790 */ 791 static void 792 bufspace_daemon(void *arg) 793 { 794 struct bufdomain *bd = arg; 795 796 EVENTHANDLER_REGISTER(shutdown_pre_sync, bufspace_daemon_shutdown, bd, 797 SHUTDOWN_PRI_LAST + 100); 798 799 BD_RUN_LOCK(bd); 800 while (!bd->bd_shutdown) { 801 BD_RUN_UNLOCK(bd); 802 803 /* 804 * Free buffers from the clean queue until we meet our 805 * targets. 806 * 807 * Theory of operation: The buffer cache is most efficient 808 * when some free buffer headers and space are always 809 * available to getnewbuf(). This daemon attempts to prevent 810 * the excessive blocking and synchronization associated 811 * with shortfall. It goes through three phases according 812 * demand: 813 * 814 * 1) The daemon wakes up voluntarily once per-second 815 * during idle periods when the counters are below 816 * the wakeup thresholds (bufspacethresh, lofreebuffers). 817 * 818 * 2) The daemon wakes up as we cross the thresholds 819 * ahead of any potential blocking. This may bounce 820 * slightly according to the rate of consumption and 821 * release. 822 * 823 * 3) The daemon and consumers are starved for working 824 * clean buffers. This is the 'bufspace' sleep below 825 * which will inefficiently trade bufs with bqrelse 826 * until we return to condition 2. 827 */ 828 while (bd->bd_bufspace > bd->bd_lobufspace || 829 bd->bd_freebuffers < bd->bd_hifreebuffers) { 830 if (buf_recycle(bd, false) != 0) { 831 if (bd_flushall(bd)) 832 continue; 833 /* 834 * Speedup dirty if we've run out of clean 835 * buffers. This is possible in particular 836 * because softdep may held many bufs locked 837 * pending writes to other bufs which are 838 * marked for delayed write, exhausting 839 * clean space until they are written. 840 */ 841 bd_speedup(); 842 BD_LOCK(bd); 843 if (bd->bd_wanted) { 844 msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 845 PRIBIO|PDROP, "bufspace", hz/10); 846 } else 847 BD_UNLOCK(bd); 848 } 849 maybe_yield(); 850 } 851 852 /* 853 * Re-check our limits and sleep. bd_running must be 854 * cleared prior to checking the limits to avoid missed 855 * wakeups. The waker will adjust one of bufspace or 856 * freebuffers prior to checking bd_running. 857 */ 858 BD_RUN_LOCK(bd); 859 if (bd->bd_shutdown) 860 break; 861 atomic_store_int(&bd->bd_running, 0); 862 if (bd->bd_bufspace < bd->bd_bufspacethresh && 863 bd->bd_freebuffers > bd->bd_lofreebuffers) { 864 msleep(&bd->bd_running, BD_RUN_LOCKPTR(bd), 865 PRIBIO, "-", hz); 866 } else { 867 /* Avoid spurious wakeups while running. */ 868 atomic_store_int(&bd->bd_running, 1); 869 } 870 } 871 wakeup(&bd->bd_shutdown); 872 BD_RUN_UNLOCK(bd); 873 kthread_exit(); 874 } 875 876 /* 877 * bufmallocadjust: 878 * 879 * Adjust the reported bufspace for a malloc managed buffer, possibly 880 * waking any waiters. 881 */ 882 static void 883 bufmallocadjust(struct buf *bp, int bufsize) 884 { 885 int diff; 886 887 KASSERT((bp->b_flags & B_MALLOC) != 0, 888 ("bufmallocadjust: non-malloc buf %p", bp)); 889 diff = bufsize - bp->b_bufsize; 890 if (diff < 0) 891 atomic_subtract_long(&bufmallocspace, -diff); 892 else 893 atomic_add_long(&bufmallocspace, diff); 894 bp->b_bufsize = bufsize; 895 } 896 897 /* 898 * runningwakeup: 899 * 900 * Wake up processes that are waiting on asynchronous writes to fall 901 * below lorunningspace. 902 */ 903 static void 904 runningwakeup(void) 905 { 906 907 mtx_lock(&rbreqlock); 908 if (runningbufreq) { 909 runningbufreq = 0; 910 wakeup(&runningbufreq); 911 } 912 mtx_unlock(&rbreqlock); 913 } 914 915 /* 916 * runningbufwakeup: 917 * 918 * Decrement the outstanding write count according. 919 */ 920 void 921 runningbufwakeup(struct buf *bp) 922 { 923 long space, bspace; 924 925 bspace = bp->b_runningbufspace; 926 if (bspace == 0) 927 return; 928 space = atomic_fetchadd_long(&runningbufspace, -bspace); 929 KASSERT(space >= bspace, ("runningbufspace underflow %ld %ld", 930 space, bspace)); 931 bp->b_runningbufspace = 0; 932 /* 933 * Only acquire the lock and wakeup on the transition from exceeding 934 * the threshold to falling below it. 935 */ 936 if (space < lorunningspace) 937 return; 938 if (space - bspace > lorunningspace) 939 return; 940 runningwakeup(); 941 } 942 943 /* 944 * waitrunningbufspace() 945 * 946 * runningbufspace is a measure of the amount of I/O currently 947 * running. This routine is used in async-write situations to 948 * prevent creating huge backups of pending writes to a device. 949 * Only asynchronous writes are governed by this function. 950 * 951 * This does NOT turn an async write into a sync write. It waits 952 * for earlier writes to complete and generally returns before the 953 * caller's write has reached the device. 954 */ 955 void 956 waitrunningbufspace(void) 957 { 958 959 mtx_lock(&rbreqlock); 960 while (runningbufspace > hirunningspace) { 961 runningbufreq = 1; 962 msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0); 963 } 964 mtx_unlock(&rbreqlock); 965 } 966 967 /* 968 * vfs_buf_test_cache: 969 * 970 * Called when a buffer is extended. This function clears the B_CACHE 971 * bit if the newly extended portion of the buffer does not contain 972 * valid data. 973 */ 974 static __inline void 975 vfs_buf_test_cache(struct buf *bp, vm_ooffset_t foff, vm_offset_t off, 976 vm_offset_t size, vm_page_t m) 977 { 978 979 /* 980 * This function and its results are protected by higher level 981 * synchronization requiring vnode and buf locks to page in and 982 * validate pages. 983 */ 984 if (bp->b_flags & B_CACHE) { 985 int base = (foff + off) & PAGE_MASK; 986 if (vm_page_is_valid(m, base, size) == 0) 987 bp->b_flags &= ~B_CACHE; 988 } 989 } 990 991 /* Wake up the buffer daemon if necessary */ 992 static void 993 bd_wakeup(void) 994 { 995 996 mtx_lock(&bdlock); 997 if (bd_request == 0) { 998 bd_request = 1; 999 wakeup(&bd_request); 1000 } 1001 mtx_unlock(&bdlock); 1002 } 1003 1004 /* 1005 * Adjust the maxbcachbuf tunable. 1006 */ 1007 static void 1008 maxbcachebuf_adjust(void) 1009 { 1010 int i; 1011 1012 /* 1013 * maxbcachebuf must be a power of 2 >= MAXBSIZE. 1014 */ 1015 i = 2; 1016 while (i * 2 <= maxbcachebuf) 1017 i *= 2; 1018 maxbcachebuf = i; 1019 if (maxbcachebuf < MAXBSIZE) 1020 maxbcachebuf = MAXBSIZE; 1021 if (maxbcachebuf > maxphys) 1022 maxbcachebuf = maxphys; 1023 if (bootverbose != 0 && maxbcachebuf != MAXBCACHEBUF) 1024 printf("maxbcachebuf=%d\n", maxbcachebuf); 1025 } 1026 1027 /* 1028 * bd_speedup - speedup the buffer cache flushing code 1029 */ 1030 void 1031 bd_speedup(void) 1032 { 1033 int needwake; 1034 1035 mtx_lock(&bdlock); 1036 needwake = 0; 1037 if (bd_speedupreq == 0 || bd_request == 0) 1038 needwake = 1; 1039 bd_speedupreq = 1; 1040 bd_request = 1; 1041 if (needwake) 1042 wakeup(&bd_request); 1043 mtx_unlock(&bdlock); 1044 } 1045 1046 #ifdef __i386__ 1047 #define TRANSIENT_DENOM 5 1048 #else 1049 #define TRANSIENT_DENOM 10 1050 #endif 1051 1052 /* 1053 * Calculating buffer cache scaling values and reserve space for buffer 1054 * headers. This is called during low level kernel initialization and 1055 * may be called more then once. We CANNOT write to the memory area 1056 * being reserved at this time. 1057 */ 1058 caddr_t 1059 kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est) 1060 { 1061 int tuned_nbuf; 1062 long maxbuf, maxbuf_sz, buf_sz, biotmap_sz; 1063 1064 /* 1065 * With KASAN or KMSAN enabled, the kernel map is shadowed. Account for 1066 * this when sizing maps based on the amount of physical memory 1067 * available. 1068 */ 1069 #if defined(KASAN) 1070 physmem_est = (physmem_est * KASAN_SHADOW_SCALE) / 1071 (KASAN_SHADOW_SCALE + 1); 1072 #elif defined(KMSAN) 1073 physmem_est /= 3; 1074 1075 /* 1076 * KMSAN cannot reliably determine whether buffer data is initialized 1077 * unless it is updated through a KVA mapping. 1078 */ 1079 unmapped_buf_allowed = 0; 1080 #endif 1081 1082 /* 1083 * physmem_est is in pages. Convert it to kilobytes (assumes 1084 * PAGE_SIZE is >= 1K) 1085 */ 1086 physmem_est = physmem_est * (PAGE_SIZE / 1024); 1087 1088 maxbcachebuf_adjust(); 1089 /* 1090 * The nominal buffer size (and minimum KVA allocation) is BKVASIZE. 1091 * For the first 64MB of ram nominally allocate sufficient buffers to 1092 * cover 1/4 of our ram. Beyond the first 64MB allocate additional 1093 * buffers to cover 1/10 of our ram over 64MB. When auto-sizing 1094 * the buffer cache we limit the eventual kva reservation to 1095 * maxbcache bytes. 1096 * 1097 * factor represents the 1/4 x ram conversion. 1098 */ 1099 if (nbuf == 0) { 1100 int factor = 4 * BKVASIZE / 1024; 1101 1102 nbuf = 50; 1103 if (physmem_est > 4096) 1104 nbuf += min((physmem_est - 4096) / factor, 1105 65536 / factor); 1106 if (physmem_est > 65536) 1107 nbuf += min((physmem_est - 65536) * 2 / (factor * 5), 1108 32 * 1024 * 1024 / (factor * 5)); 1109 1110 if (maxbcache && nbuf > maxbcache / BKVASIZE) 1111 nbuf = maxbcache / BKVASIZE; 1112 tuned_nbuf = 1; 1113 } else 1114 tuned_nbuf = 0; 1115 1116 /* XXX Avoid unsigned long overflows later on with maxbufspace. */ 1117 maxbuf = (LONG_MAX / 3) / BKVASIZE; 1118 if (nbuf > maxbuf) { 1119 if (!tuned_nbuf) 1120 printf("Warning: nbufs lowered from %d to %ld\n", nbuf, 1121 maxbuf); 1122 nbuf = maxbuf; 1123 } 1124 1125 /* 1126 * Ideal allocation size for the transient bio submap is 10% 1127 * of the maximal space buffer map. This roughly corresponds 1128 * to the amount of the buffer mapped for typical UFS load. 1129 * 1130 * Clip the buffer map to reserve space for the transient 1131 * BIOs, if its extent is bigger than 90% (80% on i386) of the 1132 * maximum buffer map extent on the platform. 1133 * 1134 * The fall-back to the maxbuf in case of maxbcache unset, 1135 * allows to not trim the buffer KVA for the architectures 1136 * with ample KVA space. 1137 */ 1138 if (bio_transient_maxcnt == 0 && unmapped_buf_allowed) { 1139 maxbuf_sz = maxbcache != 0 ? maxbcache : maxbuf * BKVASIZE; 1140 buf_sz = (long)nbuf * BKVASIZE; 1141 if (buf_sz < maxbuf_sz / TRANSIENT_DENOM * 1142 (TRANSIENT_DENOM - 1)) { 1143 /* 1144 * There is more KVA than memory. Do not 1145 * adjust buffer map size, and assign the rest 1146 * of maxbuf to transient map. 1147 */ 1148 biotmap_sz = maxbuf_sz - buf_sz; 1149 } else { 1150 /* 1151 * Buffer map spans all KVA we could afford on 1152 * this platform. Give 10% (20% on i386) of 1153 * the buffer map to the transient bio map. 1154 */ 1155 biotmap_sz = buf_sz / TRANSIENT_DENOM; 1156 buf_sz -= biotmap_sz; 1157 } 1158 if (biotmap_sz / INT_MAX > maxphys) 1159 bio_transient_maxcnt = INT_MAX; 1160 else 1161 bio_transient_maxcnt = biotmap_sz / maxphys; 1162 /* 1163 * Artificially limit to 1024 simultaneous in-flight I/Os 1164 * using the transient mapping. 1165 */ 1166 if (bio_transient_maxcnt > 1024) 1167 bio_transient_maxcnt = 1024; 1168 if (tuned_nbuf) 1169 nbuf = buf_sz / BKVASIZE; 1170 } 1171 1172 if (nswbuf == 0) { 1173 /* 1174 * Pager buffers are allocated for short periods, so scale the 1175 * number of reserved buffers based on the number of CPUs rather 1176 * than amount of memory. 1177 */ 1178 nswbuf = min(nbuf / 4, 32 * mp_ncpus); 1179 if (nswbuf < NSWBUF_MIN) 1180 nswbuf = NSWBUF_MIN; 1181 } 1182 1183 /* 1184 * Reserve space for the buffer cache buffers 1185 */ 1186 buf = (char *)v; 1187 v = (caddr_t)buf + (sizeof(struct buf) + sizeof(vm_page_t) * 1188 atop(maxbcachebuf)) * nbuf; 1189 1190 return (v); 1191 } 1192 1193 /* 1194 * Single global constant for BUF_WMESG, to avoid getting multiple 1195 * references. 1196 */ 1197 static const char buf_wmesg[] = "bufwait"; 1198 1199 /* Initialize the buffer subsystem. Called before use of any buffers. */ 1200 void 1201 bufinit(void) 1202 { 1203 struct buf *bp; 1204 int i; 1205 1206 TSENTER(); 1207 KASSERT(maxbcachebuf >= MAXBSIZE, 1208 ("maxbcachebuf (%d) must be >= MAXBSIZE (%d)\n", maxbcachebuf, 1209 MAXBSIZE)); 1210 bq_init(&bqempty, QUEUE_EMPTY, -1, "bufq empty lock"); 1211 mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF); 1212 mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF); 1213 mtx_init(&bdirtylock, "dirty buf lock", NULL, MTX_DEF); 1214 1215 unmapped_buf = (caddr_t)kva_alloc(maxphys); 1216 1217 /* finally, initialize each buffer header and stick on empty q */ 1218 for (i = 0; i < nbuf; i++) { 1219 bp = nbufp(i); 1220 bzero(bp, sizeof(*bp) + sizeof(vm_page_t) * atop(maxbcachebuf)); 1221 bp->b_flags = B_INVAL; 1222 bp->b_rcred = NOCRED; 1223 bp->b_wcred = NOCRED; 1224 bp->b_qindex = QUEUE_NONE; 1225 bp->b_domain = -1; 1226 bp->b_subqueue = mp_maxid + 1; 1227 bp->b_xflags = 0; 1228 bp->b_data = bp->b_kvabase = unmapped_buf; 1229 LIST_INIT(&bp->b_dep); 1230 BUF_LOCKINIT(bp, buf_wmesg); 1231 bq_insert(&bqempty, bp, false); 1232 } 1233 1234 /* 1235 * maxbufspace is the absolute maximum amount of buffer space we are 1236 * allowed to reserve in KVM and in real terms. The absolute maximum 1237 * is nominally used by metadata. hibufspace is the nominal maximum 1238 * used by most other requests. The differential is required to 1239 * ensure that metadata deadlocks don't occur. 1240 * 1241 * maxbufspace is based on BKVASIZE. Allocating buffers larger then 1242 * this may result in KVM fragmentation which is not handled optimally 1243 * by the system. XXX This is less true with vmem. We could use 1244 * PAGE_SIZE. 1245 */ 1246 maxbufspace = (long)nbuf * BKVASIZE; 1247 hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - maxbcachebuf * 10); 1248 lobufspace = (hibufspace / 20) * 19; /* 95% */ 1249 bufspacethresh = lobufspace + (hibufspace - lobufspace) / 2; 1250 1251 /* 1252 * Note: The 16 MiB upper limit for hirunningspace was chosen 1253 * arbitrarily and may need further tuning. It corresponds to 1254 * 128 outstanding write IO requests (if IO size is 128 KiB), 1255 * which fits with many RAID controllers' tagged queuing limits. 1256 * The lower 1 MiB limit is the historical upper limit for 1257 * hirunningspace. 1258 */ 1259 hirunningspace = lmax(lmin(roundup(hibufspace / 64, maxbcachebuf), 1260 16 * 1024 * 1024), 1024 * 1024); 1261 lorunningspace = roundup((hirunningspace * 2) / 3, maxbcachebuf); 1262 1263 /* 1264 * Limit the amount of malloc memory since it is wired permanently into 1265 * the kernel space. Even though this is accounted for in the buffer 1266 * allocation, we don't want the malloced region to grow uncontrolled. 1267 * The malloc scheme improves memory utilization significantly on 1268 * average (small) directories. 1269 */ 1270 maxbufmallocspace = hibufspace / 20; 1271 1272 /* 1273 * Reduce the chance of a deadlock occurring by limiting the number 1274 * of delayed-write dirty buffers we allow to stack up. 1275 */ 1276 hidirtybuffers = nbuf / 4 + 20; 1277 dirtybufthresh = hidirtybuffers * 9 / 10; 1278 /* 1279 * To support extreme low-memory systems, make sure hidirtybuffers 1280 * cannot eat up all available buffer space. This occurs when our 1281 * minimum cannot be met. We try to size hidirtybuffers to 3/4 our 1282 * buffer space assuming BKVASIZE'd buffers. 1283 */ 1284 while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) { 1285 hidirtybuffers >>= 1; 1286 } 1287 lodirtybuffers = hidirtybuffers / 2; 1288 1289 /* 1290 * lofreebuffers should be sufficient to avoid stalling waiting on 1291 * buf headers under heavy utilization. The bufs in per-cpu caches 1292 * are counted as free but will be unavailable to threads executing 1293 * on other cpus. 1294 * 1295 * hifreebuffers is the free target for the bufspace daemon. This 1296 * should be set appropriately to limit work per-iteration. 1297 */ 1298 lofreebuffers = MIN((nbuf / 25) + (20 * mp_ncpus), 128 * mp_ncpus); 1299 hifreebuffers = (3 * lofreebuffers) / 2; 1300 numfreebuffers = nbuf; 1301 1302 /* Setup the kva and free list allocators. */ 1303 vmem_set_reclaim(buffer_arena, bufkva_reclaim); 1304 buf_zone = uma_zcache_create("buf free cache", 1305 sizeof(struct buf) + sizeof(vm_page_t) * atop(maxbcachebuf), 1306 NULL, NULL, NULL, NULL, buf_import, buf_release, NULL, 0); 1307 1308 /* 1309 * Size the clean queue according to the amount of buffer space. 1310 * One queue per-256mb up to the max. More queues gives better 1311 * concurrency but less accurate LRU. 1312 */ 1313 buf_domains = MIN(howmany(maxbufspace, 256*1024*1024), BUF_DOMAINS); 1314 for (i = 0 ; i < buf_domains; i++) { 1315 struct bufdomain *bd; 1316 1317 bd = &bdomain[i]; 1318 bd_init(bd); 1319 bd->bd_freebuffers = nbuf / buf_domains; 1320 bd->bd_hifreebuffers = hifreebuffers / buf_domains; 1321 bd->bd_lofreebuffers = lofreebuffers / buf_domains; 1322 bd->bd_bufspace = 0; 1323 bd->bd_maxbufspace = maxbufspace / buf_domains; 1324 bd->bd_hibufspace = hibufspace / buf_domains; 1325 bd->bd_lobufspace = lobufspace / buf_domains; 1326 bd->bd_bufspacethresh = bufspacethresh / buf_domains; 1327 bd->bd_numdirtybuffers = 0; 1328 bd->bd_hidirtybuffers = hidirtybuffers / buf_domains; 1329 bd->bd_lodirtybuffers = lodirtybuffers / buf_domains; 1330 bd->bd_dirtybufthresh = dirtybufthresh / buf_domains; 1331 /* Don't allow more than 2% of bufs in the per-cpu caches. */ 1332 bd->bd_lim = nbuf / buf_domains / 50 / mp_ncpus; 1333 } 1334 getnewbufcalls = counter_u64_alloc(M_WAITOK); 1335 getnewbufrestarts = counter_u64_alloc(M_WAITOK); 1336 mappingrestarts = counter_u64_alloc(M_WAITOK); 1337 numbufallocfails = counter_u64_alloc(M_WAITOK); 1338 notbufdflushes = counter_u64_alloc(M_WAITOK); 1339 buffreekvacnt = counter_u64_alloc(M_WAITOK); 1340 bufdefragcnt = counter_u64_alloc(M_WAITOK); 1341 bufkvaspace = counter_u64_alloc(M_WAITOK); 1342 TSEXIT(); 1343 } 1344 1345 #ifdef INVARIANTS 1346 static inline void 1347 vfs_buf_check_mapped(struct buf *bp) 1348 { 1349 1350 KASSERT(bp->b_kvabase != unmapped_buf, 1351 ("mapped buf: b_kvabase was not updated %p", bp)); 1352 KASSERT(bp->b_data != unmapped_buf, 1353 ("mapped buf: b_data was not updated %p", bp)); 1354 KASSERT(bp->b_data < unmapped_buf || bp->b_data >= unmapped_buf + 1355 maxphys, ("b_data + b_offset unmapped %p", bp)); 1356 } 1357 1358 static inline void 1359 vfs_buf_check_unmapped(struct buf *bp) 1360 { 1361 1362 KASSERT(bp->b_data == unmapped_buf, 1363 ("unmapped buf: corrupted b_data %p", bp)); 1364 } 1365 1366 #define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp) 1367 #define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp) 1368 #else 1369 #define BUF_CHECK_MAPPED(bp) do {} while (0) 1370 #define BUF_CHECK_UNMAPPED(bp) do {} while (0) 1371 #endif 1372 1373 static int 1374 isbufbusy(struct buf *bp) 1375 { 1376 if (((bp->b_flags & B_INVAL) == 0 && BUF_ISLOCKED(bp)) || 1377 ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)) 1378 return (1); 1379 return (0); 1380 } 1381 1382 /* 1383 * Shutdown the system cleanly to prepare for reboot, halt, or power off. 1384 */ 1385 void 1386 bufshutdown(int show_busybufs) 1387 { 1388 static int first_buf_printf = 1; 1389 struct buf *bp; 1390 int i, iter, nbusy, pbusy; 1391 #ifndef PREEMPTION 1392 int subiter; 1393 #endif 1394 1395 /* 1396 * Sync filesystems for shutdown 1397 */ 1398 wdog_kern_pat(WD_LASTVAL); 1399 kern_sync(curthread); 1400 1401 /* 1402 * With soft updates, some buffers that are 1403 * written will be remarked as dirty until other 1404 * buffers are written. 1405 */ 1406 for (iter = pbusy = 0; iter < 20; iter++) { 1407 nbusy = 0; 1408 for (i = nbuf - 1; i >= 0; i--) { 1409 bp = nbufp(i); 1410 if (isbufbusy(bp)) 1411 nbusy++; 1412 } 1413 if (nbusy == 0) { 1414 if (first_buf_printf) 1415 printf("All buffers synced."); 1416 break; 1417 } 1418 if (first_buf_printf) { 1419 printf("Syncing disks, buffers remaining... "); 1420 first_buf_printf = 0; 1421 } 1422 printf("%d ", nbusy); 1423 if (nbusy < pbusy) 1424 iter = 0; 1425 pbusy = nbusy; 1426 1427 wdog_kern_pat(WD_LASTVAL); 1428 kern_sync(curthread); 1429 1430 #ifdef PREEMPTION 1431 /* 1432 * Spin for a while to allow interrupt threads to run. 1433 */ 1434 DELAY(50000 * iter); 1435 #else 1436 /* 1437 * Context switch several times to allow interrupt 1438 * threads to run. 1439 */ 1440 for (subiter = 0; subiter < 50 * iter; subiter++) { 1441 sched_relinquish(curthread); 1442 DELAY(1000); 1443 } 1444 #endif 1445 } 1446 printf("\n"); 1447 /* 1448 * Count only busy local buffers to prevent forcing 1449 * a fsck if we're just a client of a wedged NFS server 1450 */ 1451 nbusy = 0; 1452 for (i = nbuf - 1; i >= 0; i--) { 1453 bp = nbufp(i); 1454 if (isbufbusy(bp)) { 1455 #if 0 1456 /* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */ 1457 if (bp->b_dev == NULL) { 1458 TAILQ_REMOVE(&mountlist, 1459 bp->b_vp->v_mount, mnt_list); 1460 continue; 1461 } 1462 #endif 1463 nbusy++; 1464 if (show_busybufs > 0) { 1465 printf( 1466 "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:", 1467 nbusy, bp, bp->b_vp, bp->b_flags, 1468 (intmax_t)bp->b_blkno, 1469 (intmax_t)bp->b_lblkno); 1470 BUF_LOCKPRINTINFO(bp); 1471 if (show_busybufs > 1) 1472 vn_printf(bp->b_vp, 1473 "vnode content: "); 1474 } 1475 } 1476 } 1477 if (nbusy) { 1478 /* 1479 * Failed to sync all blocks. Indicate this and don't 1480 * unmount filesystems (thus forcing an fsck on reboot). 1481 */ 1482 BOOTTRACE("shutdown failed to sync buffers"); 1483 printf("Giving up on %d buffers\n", nbusy); 1484 DELAY(5000000); /* 5 seconds */ 1485 swapoff_all(); 1486 } else { 1487 BOOTTRACE("shutdown sync complete"); 1488 if (!first_buf_printf) 1489 printf("Final sync complete\n"); 1490 1491 /* 1492 * Unmount filesystems and perform swapoff, to quiesce 1493 * the system as much as possible. In particular, no 1494 * I/O should be initiated from top levels since it 1495 * might be abruptly terminated by reset, or otherwise 1496 * erronously handled because other parts of the 1497 * system are disabled. 1498 * 1499 * Swapoff before unmount, because file-backed swap is 1500 * non-operational after unmount of the underlying 1501 * filesystem. 1502 */ 1503 if (!KERNEL_PANICKED()) { 1504 swapoff_all(); 1505 vfs_unmountall(); 1506 } 1507 BOOTTRACE("shutdown unmounted all filesystems"); 1508 } 1509 DELAY(100000); /* wait for console output to finish */ 1510 } 1511 1512 static void 1513 bpmap_qenter(struct buf *bp) 1514 { 1515 1516 BUF_CHECK_MAPPED(bp); 1517 1518 /* 1519 * bp->b_data is relative to bp->b_offset, but 1520 * bp->b_offset may be offset into the first page. 1521 */ 1522 bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data); 1523 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 1524 bp->b_data = (caddr_t)((vm_offset_t)bp->b_data | 1525 (vm_offset_t)(bp->b_offset & PAGE_MASK)); 1526 } 1527 1528 static inline struct bufdomain * 1529 bufdomain(struct buf *bp) 1530 { 1531 1532 return (&bdomain[bp->b_domain]); 1533 } 1534 1535 static struct bufqueue * 1536 bufqueue(struct buf *bp) 1537 { 1538 1539 switch (bp->b_qindex) { 1540 case QUEUE_NONE: 1541 /* FALLTHROUGH */ 1542 case QUEUE_SENTINEL: 1543 return (NULL); 1544 case QUEUE_EMPTY: 1545 return (&bqempty); 1546 case QUEUE_DIRTY: 1547 return (&bufdomain(bp)->bd_dirtyq); 1548 case QUEUE_CLEAN: 1549 return (&bufdomain(bp)->bd_subq[bp->b_subqueue]); 1550 default: 1551 break; 1552 } 1553 panic("bufqueue(%p): Unhandled type %d\n", bp, bp->b_qindex); 1554 } 1555 1556 /* 1557 * Return the locked bufqueue that bp is a member of. 1558 */ 1559 static struct bufqueue * 1560 bufqueue_acquire(struct buf *bp) 1561 { 1562 struct bufqueue *bq, *nbq; 1563 1564 /* 1565 * bp can be pushed from a per-cpu queue to the 1566 * cleanq while we're waiting on the lock. Retry 1567 * if the queues don't match. 1568 */ 1569 bq = bufqueue(bp); 1570 BQ_LOCK(bq); 1571 for (;;) { 1572 nbq = bufqueue(bp); 1573 if (bq == nbq) 1574 break; 1575 BQ_UNLOCK(bq); 1576 BQ_LOCK(nbq); 1577 bq = nbq; 1578 } 1579 return (bq); 1580 } 1581 1582 /* 1583 * binsfree: 1584 * 1585 * Insert the buffer into the appropriate free list. Requires a 1586 * locked buffer on entry and buffer is unlocked before return. 1587 */ 1588 static void 1589 binsfree(struct buf *bp, int qindex) 1590 { 1591 struct bufdomain *bd; 1592 struct bufqueue *bq; 1593 1594 KASSERT(qindex == QUEUE_CLEAN || qindex == QUEUE_DIRTY, 1595 ("binsfree: Invalid qindex %d", qindex)); 1596 BUF_ASSERT_XLOCKED(bp); 1597 1598 /* 1599 * Handle delayed bremfree() processing. 1600 */ 1601 if (bp->b_flags & B_REMFREE) { 1602 if (bp->b_qindex == qindex) { 1603 bp->b_flags |= B_REUSE; 1604 bp->b_flags &= ~B_REMFREE; 1605 BUF_UNLOCK(bp); 1606 return; 1607 } 1608 bq = bufqueue_acquire(bp); 1609 bq_remove(bq, bp); 1610 BQ_UNLOCK(bq); 1611 } 1612 bd = bufdomain(bp); 1613 if (qindex == QUEUE_CLEAN) { 1614 if (bd->bd_lim != 0) 1615 bq = &bd->bd_subq[PCPU_GET(cpuid)]; 1616 else 1617 bq = bd->bd_cleanq; 1618 } else 1619 bq = &bd->bd_dirtyq; 1620 bq_insert(bq, bp, true); 1621 } 1622 1623 /* 1624 * buf_free: 1625 * 1626 * Free a buffer to the buf zone once it no longer has valid contents. 1627 */ 1628 static void 1629 buf_free(struct buf *bp) 1630 { 1631 1632 if (bp->b_flags & B_REMFREE) 1633 bremfreef(bp); 1634 if (bp->b_vflags & BV_BKGRDINPROG) 1635 panic("losing buffer 1"); 1636 if (bp->b_rcred != NOCRED) { 1637 crfree(bp->b_rcred); 1638 bp->b_rcred = NOCRED; 1639 } 1640 if (bp->b_wcred != NOCRED) { 1641 crfree(bp->b_wcred); 1642 bp->b_wcred = NOCRED; 1643 } 1644 if (!LIST_EMPTY(&bp->b_dep)) 1645 buf_deallocate(bp); 1646 bufkva_free(bp); 1647 atomic_add_int(&bufdomain(bp)->bd_freebuffers, 1); 1648 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1649 BUF_UNLOCK(bp); 1650 uma_zfree(buf_zone, bp); 1651 } 1652 1653 /* 1654 * buf_import: 1655 * 1656 * Import bufs into the uma cache from the buf list. The system still 1657 * expects a static array of bufs and much of the synchronization 1658 * around bufs assumes type stable storage. As a result, UMA is used 1659 * only as a per-cpu cache of bufs still maintained on a global list. 1660 */ 1661 static int 1662 buf_import(void *arg, void **store, int cnt, int domain, int flags) 1663 { 1664 struct buf *bp; 1665 int i; 1666 1667 BQ_LOCK(&bqempty); 1668 for (i = 0; i < cnt; i++) { 1669 bp = TAILQ_FIRST(&bqempty.bq_queue); 1670 if (bp == NULL) 1671 break; 1672 bq_remove(&bqempty, bp); 1673 store[i] = bp; 1674 } 1675 BQ_UNLOCK(&bqempty); 1676 1677 return (i); 1678 } 1679 1680 /* 1681 * buf_release: 1682 * 1683 * Release bufs from the uma cache back to the buffer queues. 1684 */ 1685 static void 1686 buf_release(void *arg, void **store, int cnt) 1687 { 1688 struct bufqueue *bq; 1689 struct buf *bp; 1690 int i; 1691 1692 bq = &bqempty; 1693 BQ_LOCK(bq); 1694 for (i = 0; i < cnt; i++) { 1695 bp = store[i]; 1696 /* Inline bq_insert() to batch locking. */ 1697 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1698 bp->b_flags &= ~(B_AGE | B_REUSE); 1699 bq->bq_len++; 1700 bp->b_qindex = bq->bq_index; 1701 } 1702 BQ_UNLOCK(bq); 1703 } 1704 1705 /* 1706 * buf_alloc: 1707 * 1708 * Allocate an empty buffer header. 1709 */ 1710 static struct buf * 1711 buf_alloc(struct bufdomain *bd) 1712 { 1713 struct buf *bp; 1714 int freebufs, error; 1715 1716 /* 1717 * We can only run out of bufs in the buf zone if the average buf 1718 * is less than BKVASIZE. In this case the actual wait/block will 1719 * come from buf_reycle() failing to flush one of these small bufs. 1720 */ 1721 bp = NULL; 1722 freebufs = atomic_fetchadd_int(&bd->bd_freebuffers, -1); 1723 if (freebufs > 0) 1724 bp = uma_zalloc(buf_zone, M_NOWAIT); 1725 if (bp == NULL) { 1726 atomic_add_int(&bd->bd_freebuffers, 1); 1727 bufspace_daemon_wakeup(bd); 1728 counter_u64_add(numbufallocfails, 1); 1729 return (NULL); 1730 } 1731 /* 1732 * Wake-up the bufspace daemon on transition below threshold. 1733 */ 1734 if (freebufs == bd->bd_lofreebuffers) 1735 bufspace_daemon_wakeup(bd); 1736 1737 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL); 1738 KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, 1739 error)); 1740 (void)error; 1741 1742 KASSERT(bp->b_vp == NULL, 1743 ("bp: %p still has vnode %p.", bp, bp->b_vp)); 1744 KASSERT((bp->b_flags & (B_DELWRI | B_NOREUSE)) == 0, 1745 ("invalid buffer %p flags %#x", bp, bp->b_flags)); 1746 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0, 1747 ("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags)); 1748 KASSERT(bp->b_npages == 0, 1749 ("bp: %p still has %d vm pages\n", bp, bp->b_npages)); 1750 KASSERT(bp->b_kvasize == 0, ("bp: %p still has kva\n", bp)); 1751 KASSERT(bp->b_bufsize == 0, ("bp: %p still has bufspace\n", bp)); 1752 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1753 1754 bp->b_domain = BD_DOMAIN(bd); 1755 bp->b_flags = 0; 1756 bp->b_ioflags = 0; 1757 bp->b_xflags = 0; 1758 bp->b_vflags = 0; 1759 bp->b_vp = NULL; 1760 bp->b_blkno = bp->b_lblkno = 0; 1761 bp->b_offset = NOOFFSET; 1762 bp->b_iodone = 0; 1763 bp->b_error = 0; 1764 bp->b_resid = 0; 1765 bp->b_bcount = 0; 1766 bp->b_npages = 0; 1767 bp->b_dirtyoff = bp->b_dirtyend = 0; 1768 bp->b_bufobj = NULL; 1769 bp->b_data = bp->b_kvabase = unmapped_buf; 1770 bp->b_fsprivate1 = NULL; 1771 bp->b_fsprivate2 = NULL; 1772 bp->b_fsprivate3 = NULL; 1773 LIST_INIT(&bp->b_dep); 1774 1775 return (bp); 1776 } 1777 1778 /* 1779 * buf_recycle: 1780 * 1781 * Free a buffer from the given bufqueue. kva controls whether the 1782 * freed buf must own some kva resources. This is used for 1783 * defragmenting. 1784 */ 1785 static int 1786 buf_recycle(struct bufdomain *bd, bool kva) 1787 { 1788 struct bufqueue *bq; 1789 struct buf *bp, *nbp; 1790 1791 if (kva) 1792 counter_u64_add(bufdefragcnt, 1); 1793 nbp = NULL; 1794 bq = bd->bd_cleanq; 1795 BQ_LOCK(bq); 1796 KASSERT(BQ_LOCKPTR(bq) == BD_LOCKPTR(bd), 1797 ("buf_recycle: Locks don't match")); 1798 nbp = TAILQ_FIRST(&bq->bq_queue); 1799 1800 /* 1801 * Run scan, possibly freeing data and/or kva mappings on the fly 1802 * depending. 1803 */ 1804 while ((bp = nbp) != NULL) { 1805 /* 1806 * Calculate next bp (we can only use it if we do not 1807 * release the bqlock). 1808 */ 1809 nbp = TAILQ_NEXT(bp, b_freelist); 1810 1811 /* 1812 * If we are defragging then we need a buffer with 1813 * some kva to reclaim. 1814 */ 1815 if (kva && bp->b_kvasize == 0) 1816 continue; 1817 1818 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 1819 continue; 1820 1821 /* 1822 * Implement a second chance algorithm for frequently 1823 * accessed buffers. 1824 */ 1825 if ((bp->b_flags & B_REUSE) != 0) { 1826 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1827 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1828 bp->b_flags &= ~B_REUSE; 1829 BUF_UNLOCK(bp); 1830 continue; 1831 } 1832 1833 /* 1834 * Skip buffers with background writes in progress. 1835 */ 1836 if ((bp->b_vflags & BV_BKGRDINPROG) != 0) { 1837 BUF_UNLOCK(bp); 1838 continue; 1839 } 1840 1841 KASSERT(bp->b_qindex == QUEUE_CLEAN, 1842 ("buf_recycle: inconsistent queue %d bp %p", 1843 bp->b_qindex, bp)); 1844 KASSERT(bp->b_domain == BD_DOMAIN(bd), 1845 ("getnewbuf: queue domain %d doesn't match request %d", 1846 bp->b_domain, (int)BD_DOMAIN(bd))); 1847 /* 1848 * NOTE: nbp is now entirely invalid. We can only restart 1849 * the scan from this point on. 1850 */ 1851 bq_remove(bq, bp); 1852 BQ_UNLOCK(bq); 1853 1854 /* 1855 * Requeue the background write buffer with error and 1856 * restart the scan. 1857 */ 1858 if ((bp->b_vflags & BV_BKGRDERR) != 0) { 1859 bqrelse(bp); 1860 BQ_LOCK(bq); 1861 nbp = TAILQ_FIRST(&bq->bq_queue); 1862 continue; 1863 } 1864 bp->b_flags |= B_INVAL; 1865 brelse(bp); 1866 return (0); 1867 } 1868 bd->bd_wanted = 1; 1869 BQ_UNLOCK(bq); 1870 1871 return (ENOBUFS); 1872 } 1873 1874 /* 1875 * bremfree: 1876 * 1877 * Mark the buffer for removal from the appropriate free list. 1878 * 1879 */ 1880 void 1881 bremfree(struct buf *bp) 1882 { 1883 1884 CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1885 KASSERT((bp->b_flags & B_REMFREE) == 0, 1886 ("bremfree: buffer %p already marked for delayed removal.", bp)); 1887 KASSERT(bp->b_qindex != QUEUE_NONE, 1888 ("bremfree: buffer %p not on a queue.", bp)); 1889 BUF_ASSERT_XLOCKED(bp); 1890 1891 bp->b_flags |= B_REMFREE; 1892 } 1893 1894 /* 1895 * bremfreef: 1896 * 1897 * Force an immediate removal from a free list. Used only in nfs when 1898 * it abuses the b_freelist pointer. 1899 */ 1900 void 1901 bremfreef(struct buf *bp) 1902 { 1903 struct bufqueue *bq; 1904 1905 bq = bufqueue_acquire(bp); 1906 bq_remove(bq, bp); 1907 BQ_UNLOCK(bq); 1908 } 1909 1910 static void 1911 bq_init(struct bufqueue *bq, int qindex, int subqueue, const char *lockname) 1912 { 1913 1914 mtx_init(&bq->bq_lock, lockname, NULL, MTX_DEF); 1915 TAILQ_INIT(&bq->bq_queue); 1916 bq->bq_len = 0; 1917 bq->bq_index = qindex; 1918 bq->bq_subqueue = subqueue; 1919 } 1920 1921 static void 1922 bd_init(struct bufdomain *bd) 1923 { 1924 int i; 1925 1926 /* Per-CPU clean buf queues, plus one global queue. */ 1927 bd->bd_subq = mallocarray(mp_maxid + 2, sizeof(struct bufqueue), 1928 M_BIOBUF, M_WAITOK | M_ZERO); 1929 bd->bd_cleanq = &bd->bd_subq[mp_maxid + 1]; 1930 bq_init(bd->bd_cleanq, QUEUE_CLEAN, mp_maxid + 1, "bufq clean lock"); 1931 bq_init(&bd->bd_dirtyq, QUEUE_DIRTY, -1, "bufq dirty lock"); 1932 for (i = 0; i <= mp_maxid; i++) 1933 bq_init(&bd->bd_subq[i], QUEUE_CLEAN, i, 1934 "bufq clean subqueue lock"); 1935 mtx_init(&bd->bd_run_lock, "bufspace daemon run lock", NULL, MTX_DEF); 1936 } 1937 1938 /* 1939 * bq_remove: 1940 * 1941 * Removes a buffer from the free list, must be called with the 1942 * correct qlock held. 1943 */ 1944 static void 1945 bq_remove(struct bufqueue *bq, struct buf *bp) 1946 { 1947 1948 CTR3(KTR_BUF, "bq_remove(%p) vp %p flags %X", 1949 bp, bp->b_vp, bp->b_flags); 1950 KASSERT(bp->b_qindex != QUEUE_NONE, 1951 ("bq_remove: buffer %p not on a queue.", bp)); 1952 KASSERT(bufqueue(bp) == bq, 1953 ("bq_remove: Remove buffer %p from wrong queue.", bp)); 1954 1955 BQ_ASSERT_LOCKED(bq); 1956 if (bp->b_qindex != QUEUE_EMPTY) { 1957 BUF_ASSERT_XLOCKED(bp); 1958 } 1959 KASSERT(bq->bq_len >= 1, 1960 ("queue %d underflow", bp->b_qindex)); 1961 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1962 bq->bq_len--; 1963 bp->b_qindex = QUEUE_NONE; 1964 bp->b_flags &= ~(B_REMFREE | B_REUSE); 1965 } 1966 1967 static void 1968 bd_flush(struct bufdomain *bd, struct bufqueue *bq) 1969 { 1970 struct buf *bp; 1971 1972 BQ_ASSERT_LOCKED(bq); 1973 if (bq != bd->bd_cleanq) { 1974 BD_LOCK(bd); 1975 while ((bp = TAILQ_FIRST(&bq->bq_queue)) != NULL) { 1976 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1977 TAILQ_INSERT_TAIL(&bd->bd_cleanq->bq_queue, bp, 1978 b_freelist); 1979 bp->b_subqueue = bd->bd_cleanq->bq_subqueue; 1980 } 1981 bd->bd_cleanq->bq_len += bq->bq_len; 1982 bq->bq_len = 0; 1983 } 1984 if (bd->bd_wanted) { 1985 bd->bd_wanted = 0; 1986 wakeup(&bd->bd_wanted); 1987 } 1988 if (bq != bd->bd_cleanq) 1989 BD_UNLOCK(bd); 1990 } 1991 1992 static int 1993 bd_flushall(struct bufdomain *bd) 1994 { 1995 struct bufqueue *bq; 1996 int flushed; 1997 int i; 1998 1999 if (bd->bd_lim == 0) 2000 return (0); 2001 flushed = 0; 2002 for (i = 0; i <= mp_maxid; i++) { 2003 bq = &bd->bd_subq[i]; 2004 if (bq->bq_len == 0) 2005 continue; 2006 BQ_LOCK(bq); 2007 bd_flush(bd, bq); 2008 BQ_UNLOCK(bq); 2009 flushed++; 2010 } 2011 2012 return (flushed); 2013 } 2014 2015 static void 2016 bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock) 2017 { 2018 struct bufdomain *bd; 2019 2020 if (bp->b_qindex != QUEUE_NONE) 2021 panic("bq_insert: free buffer %p onto another queue?", bp); 2022 2023 bd = bufdomain(bp); 2024 if (bp->b_flags & B_AGE) { 2025 /* Place this buf directly on the real queue. */ 2026 if (bq->bq_index == QUEUE_CLEAN) 2027 bq = bd->bd_cleanq; 2028 BQ_LOCK(bq); 2029 TAILQ_INSERT_HEAD(&bq->bq_queue, bp, b_freelist); 2030 } else { 2031 BQ_LOCK(bq); 2032 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 2033 } 2034 bp->b_flags &= ~(B_AGE | B_REUSE); 2035 bq->bq_len++; 2036 bp->b_qindex = bq->bq_index; 2037 bp->b_subqueue = bq->bq_subqueue; 2038 2039 /* 2040 * Unlock before we notify so that we don't wakeup a waiter that 2041 * fails a trylock on the buf and sleeps again. 2042 */ 2043 if (unlock) 2044 BUF_UNLOCK(bp); 2045 2046 if (bp->b_qindex == QUEUE_CLEAN) { 2047 /* 2048 * Flush the per-cpu queue and notify any waiters. 2049 */ 2050 if (bd->bd_wanted || (bq != bd->bd_cleanq && 2051 bq->bq_len >= bd->bd_lim)) 2052 bd_flush(bd, bq); 2053 } 2054 BQ_UNLOCK(bq); 2055 } 2056 2057 /* 2058 * bufkva_free: 2059 * 2060 * Free the kva allocation for a buffer. 2061 * 2062 */ 2063 static void 2064 bufkva_free(struct buf *bp) 2065 { 2066 2067 #ifdef INVARIANTS 2068 if (bp->b_kvasize == 0) { 2069 KASSERT(bp->b_kvabase == unmapped_buf && 2070 bp->b_data == unmapped_buf, 2071 ("Leaked KVA space on %p", bp)); 2072 } else if (buf_mapped(bp)) 2073 BUF_CHECK_MAPPED(bp); 2074 else 2075 BUF_CHECK_UNMAPPED(bp); 2076 #endif 2077 if (bp->b_kvasize == 0) 2078 return; 2079 2080 vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, bp->b_kvasize); 2081 counter_u64_add(bufkvaspace, -bp->b_kvasize); 2082 counter_u64_add(buffreekvacnt, 1); 2083 bp->b_data = bp->b_kvabase = unmapped_buf; 2084 bp->b_kvasize = 0; 2085 } 2086 2087 /* 2088 * bufkva_alloc: 2089 * 2090 * Allocate the buffer KVA and set b_kvasize and b_kvabase. 2091 */ 2092 static int 2093 bufkva_alloc(struct buf *bp, int maxsize, int gbflags) 2094 { 2095 vm_offset_t addr; 2096 int error; 2097 2098 KASSERT((gbflags & GB_UNMAPPED) == 0 || (gbflags & GB_KVAALLOC) != 0, 2099 ("Invalid gbflags 0x%x in %s", gbflags, __func__)); 2100 MPASS((bp->b_flags & B_MAXPHYS) == 0); 2101 KASSERT(maxsize <= maxbcachebuf, 2102 ("bufkva_alloc kva too large %d %u", maxsize, maxbcachebuf)); 2103 2104 bufkva_free(bp); 2105 2106 addr = 0; 2107 error = vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr); 2108 if (error != 0) { 2109 /* 2110 * Buffer map is too fragmented. Request the caller 2111 * to defragment the map. 2112 */ 2113 return (error); 2114 } 2115 bp->b_kvabase = (caddr_t)addr; 2116 bp->b_kvasize = maxsize; 2117 counter_u64_add(bufkvaspace, bp->b_kvasize); 2118 if ((gbflags & GB_UNMAPPED) != 0) { 2119 bp->b_data = unmapped_buf; 2120 BUF_CHECK_UNMAPPED(bp); 2121 } else { 2122 bp->b_data = bp->b_kvabase; 2123 BUF_CHECK_MAPPED(bp); 2124 } 2125 return (0); 2126 } 2127 2128 /* 2129 * bufkva_reclaim: 2130 * 2131 * Reclaim buffer kva by freeing buffers holding kva. This is a vmem 2132 * callback that fires to avoid returning failure. 2133 */ 2134 static void 2135 bufkva_reclaim(vmem_t *vmem, int flags) 2136 { 2137 bool done; 2138 int q; 2139 int i; 2140 2141 done = false; 2142 for (i = 0; i < 5; i++) { 2143 for (q = 0; q < buf_domains; q++) 2144 if (buf_recycle(&bdomain[q], true) != 0) 2145 done = true; 2146 if (done) 2147 break; 2148 } 2149 return; 2150 } 2151 2152 /* 2153 * Attempt to initiate asynchronous I/O on read-ahead blocks. We must 2154 * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set, 2155 * the buffer is valid and we do not have to do anything. 2156 */ 2157 static void 2158 breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt, 2159 struct ucred * cred, int flags, void (*ckhashfunc)(struct buf *)) 2160 { 2161 struct buf *rabp; 2162 struct thread *td; 2163 int i; 2164 2165 td = curthread; 2166 2167 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 2168 if (inmem(vp, *rablkno)) 2169 continue; 2170 rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0); 2171 if ((rabp->b_flags & B_CACHE) != 0) { 2172 brelse(rabp); 2173 continue; 2174 } 2175 #ifdef RACCT 2176 if (racct_enable) { 2177 PROC_LOCK(curproc); 2178 racct_add_buf(curproc, rabp, 0); 2179 PROC_UNLOCK(curproc); 2180 } 2181 #endif /* RACCT */ 2182 td->td_ru.ru_inblock++; 2183 rabp->b_flags |= B_ASYNC; 2184 rabp->b_flags &= ~B_INVAL; 2185 if ((flags & GB_CKHASH) != 0) { 2186 rabp->b_flags |= B_CKHASH; 2187 rabp->b_ckhashcalc = ckhashfunc; 2188 } 2189 rabp->b_ioflags &= ~BIO_ERROR; 2190 rabp->b_iocmd = BIO_READ; 2191 if (rabp->b_rcred == NOCRED && cred != NOCRED) 2192 rabp->b_rcred = crhold(cred); 2193 vfs_busy_pages(rabp, 0); 2194 BUF_KERNPROC(rabp); 2195 rabp->b_iooffset = dbtob(rabp->b_blkno); 2196 bstrategy(rabp); 2197 } 2198 } 2199 2200 /* 2201 * Entry point for bread() and breadn() via #defines in sys/buf.h. 2202 * 2203 * Get a buffer with the specified data. Look in the cache first. We 2204 * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE 2205 * is set, the buffer is valid and we do not have to do anything, see 2206 * getblk(). Also starts asynchronous I/O on read-ahead blocks. 2207 * 2208 * Always return a NULL buffer pointer (in bpp) when returning an error. 2209 * 2210 * The blkno parameter is the logical block being requested. Normally 2211 * the mapping of logical block number to disk block address is done 2212 * by calling VOP_BMAP(). However, if the mapping is already known, the 2213 * disk block address can be passed using the dblkno parameter. If the 2214 * disk block address is not known, then the same value should be passed 2215 * for blkno and dblkno. 2216 */ 2217 int 2218 breadn_flags(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, 2219 daddr_t *rablkno, int *rabsize, int cnt, struct ucred *cred, int flags, 2220 void (*ckhashfunc)(struct buf *), struct buf **bpp) 2221 { 2222 struct buf *bp; 2223 struct thread *td; 2224 int error, readwait, rv; 2225 2226 CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size); 2227 td = curthread; 2228 /* 2229 * Can only return NULL if GB_LOCK_NOWAIT or GB_SPARSE flags 2230 * are specified. 2231 */ 2232 error = getblkx(vp, blkno, dblkno, size, 0, 0, flags, &bp); 2233 if (error != 0) { 2234 *bpp = NULL; 2235 return (error); 2236 } 2237 KASSERT(blkno == bp->b_lblkno, 2238 ("getblkx returned buffer for blkno %jd instead of blkno %jd", 2239 (intmax_t)bp->b_lblkno, (intmax_t)blkno)); 2240 flags &= ~GB_NOSPARSE; 2241 *bpp = bp; 2242 2243 /* 2244 * If not found in cache, do some I/O 2245 */ 2246 readwait = 0; 2247 if ((bp->b_flags & B_CACHE) == 0) { 2248 #ifdef RACCT 2249 if (racct_enable) { 2250 PROC_LOCK(td->td_proc); 2251 racct_add_buf(td->td_proc, bp, 0); 2252 PROC_UNLOCK(td->td_proc); 2253 } 2254 #endif /* RACCT */ 2255 td->td_ru.ru_inblock++; 2256 bp->b_iocmd = BIO_READ; 2257 bp->b_flags &= ~B_INVAL; 2258 if ((flags & GB_CKHASH) != 0) { 2259 bp->b_flags |= B_CKHASH; 2260 bp->b_ckhashcalc = ckhashfunc; 2261 } 2262 if ((flags & GB_CVTENXIO) != 0) 2263 bp->b_xflags |= BX_CVTENXIO; 2264 bp->b_ioflags &= ~BIO_ERROR; 2265 if (bp->b_rcred == NOCRED && cred != NOCRED) 2266 bp->b_rcred = crhold(cred); 2267 vfs_busy_pages(bp, 0); 2268 bp->b_iooffset = dbtob(bp->b_blkno); 2269 bstrategy(bp); 2270 ++readwait; 2271 } 2272 2273 /* 2274 * Attempt to initiate asynchronous I/O on read-ahead blocks. 2275 */ 2276 breada(vp, rablkno, rabsize, cnt, cred, flags, ckhashfunc); 2277 2278 rv = 0; 2279 if (readwait) { 2280 rv = bufwait(bp); 2281 if (rv != 0) { 2282 brelse(bp); 2283 *bpp = NULL; 2284 } 2285 } 2286 return (rv); 2287 } 2288 2289 /* 2290 * Write, release buffer on completion. (Done by iodone 2291 * if async). Do not bother writing anything if the buffer 2292 * is invalid. 2293 * 2294 * Note that we set B_CACHE here, indicating that buffer is 2295 * fully valid and thus cacheable. This is true even of NFS 2296 * now so we set it generally. This could be set either here 2297 * or in biodone() since the I/O is synchronous. We put it 2298 * here. 2299 */ 2300 int 2301 bufwrite(struct buf *bp) 2302 { 2303 int oldflags; 2304 struct vnode *vp; 2305 long space; 2306 int vp_md; 2307 2308 CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2309 if ((bp->b_bufobj->bo_flag & BO_DEAD) != 0) { 2310 bp->b_flags |= B_INVAL | B_RELBUF; 2311 bp->b_flags &= ~B_CACHE; 2312 brelse(bp); 2313 return (ENXIO); 2314 } 2315 if (bp->b_flags & B_INVAL) { 2316 brelse(bp); 2317 return (0); 2318 } 2319 2320 if (bp->b_flags & B_BARRIER) 2321 atomic_add_long(&barrierwrites, 1); 2322 2323 oldflags = bp->b_flags; 2324 2325 KASSERT(!(bp->b_vflags & BV_BKGRDINPROG), 2326 ("FFS background buffer should not get here %p", bp)); 2327 2328 vp = bp->b_vp; 2329 if (vp) 2330 vp_md = vp->v_vflag & VV_MD; 2331 else 2332 vp_md = 0; 2333 2334 /* 2335 * Mark the buffer clean. Increment the bufobj write count 2336 * before bundirty() call, to prevent other thread from seeing 2337 * empty dirty list and zero counter for writes in progress, 2338 * falsely indicating that the bufobj is clean. 2339 */ 2340 bufobj_wref(bp->b_bufobj); 2341 bundirty(bp); 2342 2343 bp->b_flags &= ~B_DONE; 2344 bp->b_ioflags &= ~BIO_ERROR; 2345 bp->b_flags |= B_CACHE; 2346 bp->b_iocmd = BIO_WRITE; 2347 2348 vfs_busy_pages(bp, 1); 2349 2350 /* 2351 * Normal bwrites pipeline writes 2352 */ 2353 bp->b_runningbufspace = bp->b_bufsize; 2354 space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace); 2355 2356 #ifdef RACCT 2357 if (racct_enable) { 2358 PROC_LOCK(curproc); 2359 racct_add_buf(curproc, bp, 1); 2360 PROC_UNLOCK(curproc); 2361 } 2362 #endif /* RACCT */ 2363 curthread->td_ru.ru_oublock++; 2364 if (oldflags & B_ASYNC) 2365 BUF_KERNPROC(bp); 2366 bp->b_iooffset = dbtob(bp->b_blkno); 2367 buf_track(bp, __func__); 2368 bstrategy(bp); 2369 2370 if ((oldflags & B_ASYNC) == 0) { 2371 int rtval = bufwait(bp); 2372 brelse(bp); 2373 return (rtval); 2374 } else if (space > hirunningspace) { 2375 /* 2376 * don't allow the async write to saturate the I/O 2377 * system. We will not deadlock here because 2378 * we are blocking waiting for I/O that is already in-progress 2379 * to complete. We do not block here if it is the update 2380 * or syncer daemon trying to clean up as that can lead 2381 * to deadlock. 2382 */ 2383 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md) 2384 waitrunningbufspace(); 2385 } 2386 2387 return (0); 2388 } 2389 2390 void 2391 bufbdflush(struct bufobj *bo, struct buf *bp) 2392 { 2393 struct buf *nbp; 2394 struct bufdomain *bd; 2395 2396 bd = &bdomain[bo->bo_domain]; 2397 if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh + 10) { 2398 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); 2399 altbufferflushes++; 2400 } else if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh) { 2401 BO_LOCK(bo); 2402 /* 2403 * Try to find a buffer to flush. 2404 */ 2405 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2406 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2407 BUF_LOCK(nbp, 2408 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2409 continue; 2410 if (bp == nbp) 2411 panic("bdwrite: found ourselves"); 2412 BO_UNLOCK(bo); 2413 /* Don't countdeps with the bo lock held. */ 2414 if (buf_countdeps(nbp, 0)) { 2415 BO_LOCK(bo); 2416 BUF_UNLOCK(nbp); 2417 continue; 2418 } 2419 if (nbp->b_flags & B_CLUSTEROK) { 2420 vfs_bio_awrite(nbp); 2421 } else { 2422 bremfree(nbp); 2423 bawrite(nbp); 2424 } 2425 dirtybufferflushes++; 2426 break; 2427 } 2428 if (nbp == NULL) 2429 BO_UNLOCK(bo); 2430 } 2431 } 2432 2433 /* 2434 * Delayed write. (Buffer is marked dirty). Do not bother writing 2435 * anything if the buffer is marked invalid. 2436 * 2437 * Note that since the buffer must be completely valid, we can safely 2438 * set B_CACHE. In fact, we have to set B_CACHE here rather then in 2439 * biodone() in order to prevent getblk from writing the buffer 2440 * out synchronously. 2441 */ 2442 void 2443 bdwrite(struct buf *bp) 2444 { 2445 struct thread *td = curthread; 2446 struct vnode *vp; 2447 struct bufobj *bo; 2448 2449 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2450 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2451 KASSERT((bp->b_flags & B_BARRIER) == 0, 2452 ("Barrier request in delayed write %p", bp)); 2453 2454 if (bp->b_flags & B_INVAL) { 2455 brelse(bp); 2456 return; 2457 } 2458 2459 /* 2460 * If we have too many dirty buffers, don't create any more. 2461 * If we are wildly over our limit, then force a complete 2462 * cleanup. Otherwise, just keep the situation from getting 2463 * out of control. Note that we have to avoid a recursive 2464 * disaster and not try to clean up after our own cleanup! 2465 */ 2466 vp = bp->b_vp; 2467 bo = bp->b_bufobj; 2468 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) { 2469 td->td_pflags |= TDP_INBDFLUSH; 2470 BO_BDFLUSH(bo, bp); 2471 td->td_pflags &= ~TDP_INBDFLUSH; 2472 } else 2473 recursiveflushes++; 2474 2475 bdirty(bp); 2476 /* 2477 * Set B_CACHE, indicating that the buffer is fully valid. This is 2478 * true even of NFS now. 2479 */ 2480 bp->b_flags |= B_CACHE; 2481 2482 /* 2483 * This bmap keeps the system from needing to do the bmap later, 2484 * perhaps when the system is attempting to do a sync. Since it 2485 * is likely that the indirect block -- or whatever other datastructure 2486 * that the filesystem needs is still in memory now, it is a good 2487 * thing to do this. Note also, that if the pageout daemon is 2488 * requesting a sync -- there might not be enough memory to do 2489 * the bmap then... So, this is important to do. 2490 */ 2491 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) { 2492 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 2493 } 2494 2495 buf_track(bp, __func__); 2496 2497 /* 2498 * Set the *dirty* buffer range based upon the VM system dirty 2499 * pages. 2500 * 2501 * Mark the buffer pages as clean. We need to do this here to 2502 * satisfy the vnode_pager and the pageout daemon, so that it 2503 * thinks that the pages have been "cleaned". Note that since 2504 * the pages are in a delayed write buffer -- the VFS layer 2505 * "will" see that the pages get written out on the next sync, 2506 * or perhaps the cluster will be completed. 2507 */ 2508 vfs_clean_pages_dirty_buf(bp); 2509 bqrelse(bp); 2510 2511 /* 2512 * note: we cannot initiate I/O from a bdwrite even if we wanted to, 2513 * due to the softdep code. 2514 */ 2515 } 2516 2517 /* 2518 * bdirty: 2519 * 2520 * Turn buffer into delayed write request. We must clear BIO_READ and 2521 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to 2522 * itself to properly update it in the dirty/clean lists. We mark it 2523 * B_DONE to ensure that any asynchronization of the buffer properly 2524 * clears B_DONE ( else a panic will occur later ). 2525 * 2526 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which 2527 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty() 2528 * should only be called if the buffer is known-good. 2529 * 2530 * Since the buffer is not on a queue, we do not update the numfreebuffers 2531 * count. 2532 * 2533 * The buffer must be on QUEUE_NONE. 2534 */ 2535 void 2536 bdirty(struct buf *bp) 2537 { 2538 2539 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X", 2540 bp, bp->b_vp, bp->b_flags); 2541 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2542 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2543 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2544 bp->b_flags &= ~(B_RELBUF); 2545 bp->b_iocmd = BIO_WRITE; 2546 2547 if ((bp->b_flags & B_DELWRI) == 0) { 2548 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI; 2549 reassignbuf(bp); 2550 bdirtyadd(bp); 2551 } 2552 } 2553 2554 /* 2555 * bundirty: 2556 * 2557 * Clear B_DELWRI for buffer. 2558 * 2559 * Since the buffer is not on a queue, we do not update the numfreebuffers 2560 * count. 2561 * 2562 * The buffer must be on QUEUE_NONE. 2563 */ 2564 2565 void 2566 bundirty(struct buf *bp) 2567 { 2568 2569 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2570 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2571 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2572 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2573 2574 if (bp->b_flags & B_DELWRI) { 2575 bp->b_flags &= ~B_DELWRI; 2576 reassignbuf(bp); 2577 bdirtysub(bp); 2578 } 2579 /* 2580 * Since it is now being written, we can clear its deferred write flag. 2581 */ 2582 bp->b_flags &= ~B_DEFERRED; 2583 } 2584 2585 /* 2586 * bawrite: 2587 * 2588 * Asynchronous write. Start output on a buffer, but do not wait for 2589 * it to complete. The buffer is released when the output completes. 2590 * 2591 * bwrite() ( or the VOP routine anyway ) is responsible for handling 2592 * B_INVAL buffers. Not us. 2593 */ 2594 void 2595 bawrite(struct buf *bp) 2596 { 2597 2598 bp->b_flags |= B_ASYNC; 2599 (void) bwrite(bp); 2600 } 2601 2602 /* 2603 * babarrierwrite: 2604 * 2605 * Asynchronous barrier write. Start output on a buffer, but do not 2606 * wait for it to complete. Place a write barrier after this write so 2607 * that this buffer and all buffers written before it are committed to 2608 * the disk before any buffers written after this write are committed 2609 * to the disk. The buffer is released when the output completes. 2610 */ 2611 void 2612 babarrierwrite(struct buf *bp) 2613 { 2614 2615 bp->b_flags |= B_ASYNC | B_BARRIER; 2616 (void) bwrite(bp); 2617 } 2618 2619 /* 2620 * bbarrierwrite: 2621 * 2622 * Synchronous barrier write. Start output on a buffer and wait for 2623 * it to complete. Place a write barrier after this write so that 2624 * this buffer and all buffers written before it are committed to 2625 * the disk before any buffers written after this write are committed 2626 * to the disk. The buffer is released when the output completes. 2627 */ 2628 int 2629 bbarrierwrite(struct buf *bp) 2630 { 2631 2632 bp->b_flags |= B_BARRIER; 2633 return (bwrite(bp)); 2634 } 2635 2636 /* 2637 * bwillwrite: 2638 * 2639 * Called prior to the locking of any vnodes when we are expecting to 2640 * write. We do not want to starve the buffer cache with too many 2641 * dirty buffers so we block here. By blocking prior to the locking 2642 * of any vnodes we attempt to avoid the situation where a locked vnode 2643 * prevents the various system daemons from flushing related buffers. 2644 */ 2645 void 2646 bwillwrite(void) 2647 { 2648 2649 if (buf_dirty_count_severe()) { 2650 mtx_lock(&bdirtylock); 2651 while (buf_dirty_count_severe()) { 2652 bdirtywait = 1; 2653 msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4), 2654 "flswai", 0); 2655 } 2656 mtx_unlock(&bdirtylock); 2657 } 2658 } 2659 2660 /* 2661 * Return true if we have too many dirty buffers. 2662 */ 2663 int 2664 buf_dirty_count_severe(void) 2665 { 2666 2667 return (!BIT_EMPTY(BUF_DOMAINS, &bdhidirty)); 2668 } 2669 2670 /* 2671 * brelse: 2672 * 2673 * Release a busy buffer and, if requested, free its resources. The 2674 * buffer will be stashed in the appropriate bufqueue[] allowing it 2675 * to be accessed later as a cache entity or reused for other purposes. 2676 */ 2677 void 2678 brelse(struct buf *bp) 2679 { 2680 struct mount *v_mnt; 2681 int qindex; 2682 2683 /* 2684 * Many functions erroneously call brelse with a NULL bp under rare 2685 * error conditions. Simply return when called with a NULL bp. 2686 */ 2687 if (bp == NULL) 2688 return; 2689 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X", 2690 bp, bp->b_vp, bp->b_flags); 2691 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2692 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2693 KASSERT((bp->b_flags & B_VMIO) != 0 || (bp->b_flags & B_NOREUSE) == 0, 2694 ("brelse: non-VMIO buffer marked NOREUSE")); 2695 2696 if (BUF_LOCKRECURSED(bp)) { 2697 /* 2698 * Do not process, in particular, do not handle the 2699 * B_INVAL/B_RELBUF and do not release to free list. 2700 */ 2701 BUF_UNLOCK(bp); 2702 return; 2703 } 2704 2705 if (bp->b_flags & B_MANAGED) { 2706 bqrelse(bp); 2707 return; 2708 } 2709 2710 if (LIST_EMPTY(&bp->b_dep)) { 2711 bp->b_flags &= ~B_IOSTARTED; 2712 } else { 2713 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2714 ("brelse: SU io not finished bp %p", bp)); 2715 } 2716 2717 if ((bp->b_vflags & (BV_BKGRDINPROG | BV_BKGRDERR)) == BV_BKGRDERR) { 2718 BO_LOCK(bp->b_bufobj); 2719 bp->b_vflags &= ~BV_BKGRDERR; 2720 BO_UNLOCK(bp->b_bufobj); 2721 bdirty(bp); 2722 } 2723 2724 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2725 (bp->b_flags & B_INVALONERR)) { 2726 /* 2727 * Forced invalidation of dirty buffer contents, to be used 2728 * after a failed write in the rare case that the loss of the 2729 * contents is acceptable. The buffer is invalidated and 2730 * freed. 2731 */ 2732 bp->b_flags |= B_INVAL | B_RELBUF | B_NOCACHE; 2733 bp->b_flags &= ~(B_ASYNC | B_CACHE); 2734 } 2735 2736 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2737 (bp->b_error != ENXIO || !LIST_EMPTY(&bp->b_dep)) && 2738 !(bp->b_flags & B_INVAL)) { 2739 /* 2740 * Failed write, redirty. All errors except ENXIO (which 2741 * means the device is gone) are treated as being 2742 * transient. 2743 * 2744 * XXX Treating EIO as transient is not correct; the 2745 * contract with the local storage device drivers is that 2746 * they will only return EIO once the I/O is no longer 2747 * retriable. Network I/O also respects this through the 2748 * guarantees of TCP and/or the internal retries of NFS. 2749 * ENOMEM might be transient, but we also have no way of 2750 * knowing when its ok to retry/reschedule. In general, 2751 * this entire case should be made obsolete through better 2752 * error handling/recovery and resource scheduling. 2753 * 2754 * Do this also for buffers that failed with ENXIO, but have 2755 * non-empty dependencies - the soft updates code might need 2756 * to access the buffer to untangle them. 2757 * 2758 * Must clear BIO_ERROR to prevent pages from being scrapped. 2759 */ 2760 bp->b_ioflags &= ~BIO_ERROR; 2761 bdirty(bp); 2762 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) || 2763 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) { 2764 /* 2765 * Either a failed read I/O, or we were asked to free or not 2766 * cache the buffer, or we failed to write to a device that's 2767 * no longer present. 2768 */ 2769 bp->b_flags |= B_INVAL; 2770 if (!LIST_EMPTY(&bp->b_dep)) 2771 buf_deallocate(bp); 2772 if (bp->b_flags & B_DELWRI) 2773 bdirtysub(bp); 2774 bp->b_flags &= ~(B_DELWRI | B_CACHE); 2775 if ((bp->b_flags & B_VMIO) == 0) { 2776 allocbuf(bp, 0); 2777 if (bp->b_vp) 2778 brelvp(bp); 2779 } 2780 } 2781 2782 /* 2783 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_truncate() 2784 * is called with B_DELWRI set, the underlying pages may wind up 2785 * getting freed causing a previous write (bdwrite()) to get 'lost' 2786 * because pages associated with a B_DELWRI bp are marked clean. 2787 * 2788 * We still allow the B_INVAL case to call vfs_vmio_truncate(), even 2789 * if B_DELWRI is set. 2790 */ 2791 if (bp->b_flags & B_DELWRI) 2792 bp->b_flags &= ~B_RELBUF; 2793 2794 /* 2795 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 2796 * constituted, not even NFS buffers now. Two flags effect this. If 2797 * B_INVAL, the struct buf is invalidated but the VM object is kept 2798 * around ( i.e. so it is trivial to reconstitute the buffer later ). 2799 * 2800 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be 2801 * invalidated. BIO_ERROR cannot be set for a failed write unless the 2802 * buffer is also B_INVAL because it hits the re-dirtying code above. 2803 * 2804 * Normally we can do this whether a buffer is B_DELWRI or not. If 2805 * the buffer is an NFS buffer, it is tracking piecemeal writes or 2806 * the commit state and we cannot afford to lose the buffer. If the 2807 * buffer has a background write in progress, we need to keep it 2808 * around to prevent it from being reconstituted and starting a second 2809 * background write. 2810 */ 2811 2812 v_mnt = bp->b_vp != NULL ? bp->b_vp->v_mount : NULL; 2813 2814 if ((bp->b_flags & B_VMIO) && (bp->b_flags & B_NOCACHE || 2815 (bp->b_ioflags & BIO_ERROR && bp->b_iocmd == BIO_READ)) && 2816 (v_mnt == NULL || (v_mnt->mnt_vfc->vfc_flags & VFCF_NETWORK) == 0 || 2817 vn_isdisk(bp->b_vp) || (bp->b_flags & B_DELWRI) == 0)) { 2818 vfs_vmio_invalidate(bp); 2819 allocbuf(bp, 0); 2820 } 2821 2822 if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0 || 2823 (bp->b_flags & (B_DELWRI | B_NOREUSE)) == B_NOREUSE) { 2824 allocbuf(bp, 0); 2825 bp->b_flags &= ~B_NOREUSE; 2826 if (bp->b_vp != NULL) 2827 brelvp(bp); 2828 } 2829 2830 /* 2831 * If the buffer has junk contents signal it and eventually 2832 * clean up B_DELWRI and diassociate the vnode so that gbincore() 2833 * doesn't find it. 2834 */ 2835 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 || 2836 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0) 2837 bp->b_flags |= B_INVAL; 2838 if (bp->b_flags & B_INVAL) { 2839 if (bp->b_flags & B_DELWRI) 2840 bundirty(bp); 2841 if (bp->b_vp) 2842 brelvp(bp); 2843 } 2844 2845 buf_track(bp, __func__); 2846 2847 /* buffers with no memory */ 2848 if (bp->b_bufsize == 0) { 2849 buf_free(bp); 2850 return; 2851 } 2852 /* buffers with junk contents */ 2853 if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) || 2854 (bp->b_ioflags & BIO_ERROR)) { 2855 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 2856 if (bp->b_vflags & BV_BKGRDINPROG) 2857 panic("losing buffer 2"); 2858 qindex = QUEUE_CLEAN; 2859 bp->b_flags |= B_AGE; 2860 /* remaining buffers */ 2861 } else if (bp->b_flags & B_DELWRI) 2862 qindex = QUEUE_DIRTY; 2863 else 2864 qindex = QUEUE_CLEAN; 2865 2866 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) 2867 panic("brelse: not dirty"); 2868 2869 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_RELBUF | B_DIRECT); 2870 bp->b_xflags &= ~(BX_CVTENXIO); 2871 /* binsfree unlocks bp. */ 2872 binsfree(bp, qindex); 2873 } 2874 2875 /* 2876 * Release a buffer back to the appropriate queue but do not try to free 2877 * it. The buffer is expected to be used again soon. 2878 * 2879 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by 2880 * biodone() to requeue an async I/O on completion. It is also used when 2881 * known good buffers need to be requeued but we think we may need the data 2882 * again soon. 2883 * 2884 * XXX we should be able to leave the B_RELBUF hint set on completion. 2885 */ 2886 void 2887 bqrelse(struct buf *bp) 2888 { 2889 int qindex; 2890 2891 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2892 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2893 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2894 2895 qindex = QUEUE_NONE; 2896 if (BUF_LOCKRECURSED(bp)) { 2897 /* do not release to free list */ 2898 BUF_UNLOCK(bp); 2899 return; 2900 } 2901 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 2902 bp->b_xflags &= ~(BX_CVTENXIO); 2903 2904 if (LIST_EMPTY(&bp->b_dep)) { 2905 bp->b_flags &= ~B_IOSTARTED; 2906 } else { 2907 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2908 ("bqrelse: SU io not finished bp %p", bp)); 2909 } 2910 2911 if (bp->b_flags & B_MANAGED) { 2912 if (bp->b_flags & B_REMFREE) 2913 bremfreef(bp); 2914 goto out; 2915 } 2916 2917 /* buffers with stale but valid contents */ 2918 if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG | 2919 BV_BKGRDERR)) == BV_BKGRDERR) { 2920 BO_LOCK(bp->b_bufobj); 2921 bp->b_vflags &= ~BV_BKGRDERR; 2922 BO_UNLOCK(bp->b_bufobj); 2923 qindex = QUEUE_DIRTY; 2924 } else { 2925 if ((bp->b_flags & B_DELWRI) == 0 && 2926 (bp->b_xflags & BX_VNDIRTY)) 2927 panic("bqrelse: not dirty"); 2928 if ((bp->b_flags & B_NOREUSE) != 0) { 2929 brelse(bp); 2930 return; 2931 } 2932 qindex = QUEUE_CLEAN; 2933 } 2934 buf_track(bp, __func__); 2935 /* binsfree unlocks bp. */ 2936 binsfree(bp, qindex); 2937 return; 2938 2939 out: 2940 buf_track(bp, __func__); 2941 /* unlock */ 2942 BUF_UNLOCK(bp); 2943 } 2944 2945 /* 2946 * Complete I/O to a VMIO backed page. Validate the pages as appropriate, 2947 * restore bogus pages. 2948 */ 2949 static void 2950 vfs_vmio_iodone(struct buf *bp) 2951 { 2952 vm_ooffset_t foff; 2953 vm_page_t m; 2954 vm_object_t obj; 2955 struct vnode *vp __unused; 2956 int i, iosize, resid; 2957 bool bogus; 2958 2959 obj = bp->b_bufobj->bo_object; 2960 KASSERT(blockcount_read(&obj->paging_in_progress) >= bp->b_npages, 2961 ("vfs_vmio_iodone: paging in progress(%d) < b_npages(%d)", 2962 blockcount_read(&obj->paging_in_progress), bp->b_npages)); 2963 2964 vp = bp->b_vp; 2965 VNPASS(vp->v_holdcnt > 0, vp); 2966 VNPASS(vp->v_object != NULL, vp); 2967 2968 foff = bp->b_offset; 2969 KASSERT(bp->b_offset != NOOFFSET, 2970 ("vfs_vmio_iodone: bp %p has no buffer offset", bp)); 2971 2972 bogus = false; 2973 iosize = bp->b_bcount - bp->b_resid; 2974 for (i = 0; i < bp->b_npages; i++) { 2975 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff; 2976 if (resid > iosize) 2977 resid = iosize; 2978 2979 /* 2980 * cleanup bogus pages, restoring the originals 2981 */ 2982 m = bp->b_pages[i]; 2983 if (m == bogus_page) { 2984 bogus = true; 2985 m = vm_page_relookup(obj, OFF_TO_IDX(foff)); 2986 if (m == NULL) 2987 panic("biodone: page disappeared!"); 2988 bp->b_pages[i] = m; 2989 } else if ((bp->b_iocmd == BIO_READ) && resid > 0) { 2990 /* 2991 * In the write case, the valid and clean bits are 2992 * already changed correctly ( see bdwrite() ), so we 2993 * only need to do this here in the read case. 2994 */ 2995 KASSERT((m->dirty & vm_page_bits(foff & PAGE_MASK, 2996 resid)) == 0, ("vfs_vmio_iodone: page %p " 2997 "has unexpected dirty bits", m)); 2998 vfs_page_set_valid(bp, foff, m); 2999 } 3000 KASSERT(OFF_TO_IDX(foff) == m->pindex, 3001 ("vfs_vmio_iodone: foff(%jd)/pindex(%ju) mismatch", 3002 (intmax_t)foff, (uintmax_t)m->pindex)); 3003 3004 vm_page_sunbusy(m); 3005 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3006 iosize -= resid; 3007 } 3008 vm_object_pip_wakeupn(obj, bp->b_npages); 3009 if (bogus && buf_mapped(bp)) { 3010 BUF_CHECK_MAPPED(bp); 3011 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 3012 bp->b_pages, bp->b_npages); 3013 } 3014 } 3015 3016 /* 3017 * Perform page invalidation when a buffer is released. The fully invalid 3018 * pages will be reclaimed later in vfs_vmio_truncate(). 3019 */ 3020 static void 3021 vfs_vmio_invalidate(struct buf *bp) 3022 { 3023 vm_object_t obj; 3024 vm_page_t m; 3025 int flags, i, resid, poffset, presid; 3026 3027 if (buf_mapped(bp)) { 3028 BUF_CHECK_MAPPED(bp); 3029 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages); 3030 } else 3031 BUF_CHECK_UNMAPPED(bp); 3032 /* 3033 * Get the base offset and length of the buffer. Note that 3034 * in the VMIO case if the buffer block size is not 3035 * page-aligned then b_data pointer may not be page-aligned. 3036 * But our b_pages[] array *IS* page aligned. 3037 * 3038 * block sizes less then DEV_BSIZE (usually 512) are not 3039 * supported due to the page granularity bits (m->valid, 3040 * m->dirty, etc...). 3041 * 3042 * See man buf(9) for more information 3043 */ 3044 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3045 obj = bp->b_bufobj->bo_object; 3046 resid = bp->b_bufsize; 3047 poffset = bp->b_offset & PAGE_MASK; 3048 VM_OBJECT_WLOCK(obj); 3049 for (i = 0; i < bp->b_npages; i++) { 3050 m = bp->b_pages[i]; 3051 if (m == bogus_page) 3052 panic("vfs_vmio_invalidate: Unexpected bogus page."); 3053 bp->b_pages[i] = NULL; 3054 3055 presid = resid > (PAGE_SIZE - poffset) ? 3056 (PAGE_SIZE - poffset) : resid; 3057 KASSERT(presid >= 0, ("brelse: extra page")); 3058 vm_page_busy_acquire(m, VM_ALLOC_SBUSY); 3059 if (pmap_page_wired_mappings(m) == 0) 3060 vm_page_set_invalid(m, poffset, presid); 3061 vm_page_sunbusy(m); 3062 vm_page_release_locked(m, flags); 3063 resid -= presid; 3064 poffset = 0; 3065 } 3066 VM_OBJECT_WUNLOCK(obj); 3067 bp->b_npages = 0; 3068 } 3069 3070 /* 3071 * Page-granular truncation of an existing VMIO buffer. 3072 */ 3073 static void 3074 vfs_vmio_truncate(struct buf *bp, int desiredpages) 3075 { 3076 vm_object_t obj; 3077 vm_page_t m; 3078 int flags, i; 3079 3080 if (bp->b_npages == desiredpages) 3081 return; 3082 3083 if (buf_mapped(bp)) { 3084 BUF_CHECK_MAPPED(bp); 3085 pmap_qremove((vm_offset_t)trunc_page((vm_offset_t)bp->b_data) + 3086 (desiredpages << PAGE_SHIFT), bp->b_npages - desiredpages); 3087 } else 3088 BUF_CHECK_UNMAPPED(bp); 3089 3090 /* 3091 * The object lock is needed only if we will attempt to free pages. 3092 */ 3093 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3094 if ((bp->b_flags & B_DIRECT) != 0) { 3095 flags |= VPR_TRYFREE; 3096 obj = bp->b_bufobj->bo_object; 3097 VM_OBJECT_WLOCK(obj); 3098 } else { 3099 obj = NULL; 3100 } 3101 for (i = desiredpages; i < bp->b_npages; i++) { 3102 m = bp->b_pages[i]; 3103 KASSERT(m != bogus_page, ("allocbuf: bogus page found")); 3104 bp->b_pages[i] = NULL; 3105 if (obj != NULL) 3106 vm_page_release_locked(m, flags); 3107 else 3108 vm_page_release(m, flags); 3109 } 3110 if (obj != NULL) 3111 VM_OBJECT_WUNLOCK(obj); 3112 bp->b_npages = desiredpages; 3113 } 3114 3115 /* 3116 * Byte granular extension of VMIO buffers. 3117 */ 3118 static void 3119 vfs_vmio_extend(struct buf *bp, int desiredpages, int size) 3120 { 3121 /* 3122 * We are growing the buffer, possibly in a 3123 * byte-granular fashion. 3124 */ 3125 vm_object_t obj; 3126 vm_offset_t toff; 3127 vm_offset_t tinc; 3128 vm_page_t m; 3129 3130 /* 3131 * Step 1, bring in the VM pages from the object, allocating 3132 * them if necessary. We must clear B_CACHE if these pages 3133 * are not valid for the range covered by the buffer. 3134 */ 3135 obj = bp->b_bufobj->bo_object; 3136 if (bp->b_npages < desiredpages) { 3137 KASSERT(desiredpages <= atop(maxbcachebuf), 3138 ("vfs_vmio_extend past maxbcachebuf %p %d %u", 3139 bp, desiredpages, maxbcachebuf)); 3140 3141 /* 3142 * We must allocate system pages since blocking 3143 * here could interfere with paging I/O, no 3144 * matter which process we are. 3145 * 3146 * Only exclusive busy can be tested here. 3147 * Blocking on shared busy might lead to 3148 * deadlocks once allocbuf() is called after 3149 * pages are vfs_busy_pages(). 3150 */ 3151 (void)vm_page_grab_pages_unlocked(obj, 3152 OFF_TO_IDX(bp->b_offset) + bp->b_npages, 3153 VM_ALLOC_SYSTEM | VM_ALLOC_IGN_SBUSY | 3154 VM_ALLOC_NOBUSY | VM_ALLOC_WIRED, 3155 &bp->b_pages[bp->b_npages], desiredpages - bp->b_npages); 3156 bp->b_npages = desiredpages; 3157 } 3158 3159 /* 3160 * Step 2. We've loaded the pages into the buffer, 3161 * we have to figure out if we can still have B_CACHE 3162 * set. Note that B_CACHE is set according to the 3163 * byte-granular range ( bcount and size ), not the 3164 * aligned range ( newbsize ). 3165 * 3166 * The VM test is against m->valid, which is DEV_BSIZE 3167 * aligned. Needless to say, the validity of the data 3168 * needs to also be DEV_BSIZE aligned. Note that this 3169 * fails with NFS if the server or some other client 3170 * extends the file's EOF. If our buffer is resized, 3171 * B_CACHE may remain set! XXX 3172 */ 3173 toff = bp->b_bcount; 3174 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK); 3175 while ((bp->b_flags & B_CACHE) && toff < size) { 3176 vm_pindex_t pi; 3177 3178 if (tinc > (size - toff)) 3179 tinc = size - toff; 3180 pi = ((bp->b_offset & PAGE_MASK) + toff) >> PAGE_SHIFT; 3181 m = bp->b_pages[pi]; 3182 vfs_buf_test_cache(bp, bp->b_offset, toff, tinc, m); 3183 toff += tinc; 3184 tinc = PAGE_SIZE; 3185 } 3186 3187 /* 3188 * Step 3, fixup the KVA pmap. 3189 */ 3190 if (buf_mapped(bp)) 3191 bpmap_qenter(bp); 3192 else 3193 BUF_CHECK_UNMAPPED(bp); 3194 } 3195 3196 /* 3197 * Check to see if a block at a particular lbn is available for a clustered 3198 * write. 3199 */ 3200 static int 3201 vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno) 3202 { 3203 struct buf *bpa; 3204 int match; 3205 3206 match = 0; 3207 3208 /* If the buf isn't in core skip it */ 3209 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL) 3210 return (0); 3211 3212 /* If the buf is busy we don't want to wait for it */ 3213 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 3214 return (0); 3215 3216 /* Only cluster with valid clusterable delayed write buffers */ 3217 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) != 3218 (B_DELWRI | B_CLUSTEROK)) 3219 goto done; 3220 3221 if (bpa->b_bufsize != size) 3222 goto done; 3223 3224 /* 3225 * Check to see if it is in the expected place on disk and that the 3226 * block has been mapped. 3227 */ 3228 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno)) 3229 match = 1; 3230 done: 3231 BUF_UNLOCK(bpa); 3232 return (match); 3233 } 3234 3235 /* 3236 * vfs_bio_awrite: 3237 * 3238 * Implement clustered async writes for clearing out B_DELWRI buffers. 3239 * This is much better then the old way of writing only one buffer at 3240 * a time. Note that we may not be presented with the buffers in the 3241 * correct order, so we search for the cluster in both directions. 3242 */ 3243 int 3244 vfs_bio_awrite(struct buf *bp) 3245 { 3246 struct bufobj *bo; 3247 int i; 3248 int j; 3249 daddr_t lblkno = bp->b_lblkno; 3250 struct vnode *vp = bp->b_vp; 3251 int ncl; 3252 int nwritten; 3253 int size; 3254 int maxcl; 3255 int gbflags; 3256 3257 bo = &vp->v_bufobj; 3258 gbflags = (bp->b_data == unmapped_buf) ? GB_UNMAPPED : 0; 3259 /* 3260 * right now we support clustered writing only to regular files. If 3261 * we find a clusterable block we could be in the middle of a cluster 3262 * rather then at the beginning. 3263 */ 3264 if ((vp->v_type == VREG) && 3265 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 3266 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 3267 size = vp->v_mount->mnt_stat.f_iosize; 3268 maxcl = maxphys / size; 3269 3270 BO_RLOCK(bo); 3271 for (i = 1; i < maxcl; i++) 3272 if (vfs_bio_clcheck(vp, size, lblkno + i, 3273 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0) 3274 break; 3275 3276 for (j = 1; i + j <= maxcl && j <= lblkno; j++) 3277 if (vfs_bio_clcheck(vp, size, lblkno - j, 3278 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0) 3279 break; 3280 BO_RUNLOCK(bo); 3281 --j; 3282 ncl = i + j; 3283 /* 3284 * this is a possible cluster write 3285 */ 3286 if (ncl != 1) { 3287 BUF_UNLOCK(bp); 3288 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, 3289 gbflags); 3290 return (nwritten); 3291 } 3292 } 3293 bremfree(bp); 3294 bp->b_flags |= B_ASYNC; 3295 /* 3296 * default (old) behavior, writing out only one block 3297 * 3298 * XXX returns b_bufsize instead of b_bcount for nwritten? 3299 */ 3300 nwritten = bp->b_bufsize; 3301 (void) bwrite(bp); 3302 3303 return (nwritten); 3304 } 3305 3306 /* 3307 * getnewbuf_kva: 3308 * 3309 * Allocate KVA for an empty buf header according to gbflags. 3310 */ 3311 static int 3312 getnewbuf_kva(struct buf *bp, int gbflags, int maxsize) 3313 { 3314 3315 if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_UNMAPPED) { 3316 /* 3317 * In order to keep fragmentation sane we only allocate kva 3318 * in BKVASIZE chunks. XXX with vmem we can do page size. 3319 */ 3320 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK; 3321 3322 if (maxsize != bp->b_kvasize && 3323 bufkva_alloc(bp, maxsize, gbflags)) 3324 return (ENOSPC); 3325 } 3326 return (0); 3327 } 3328 3329 /* 3330 * getnewbuf: 3331 * 3332 * Find and initialize a new buffer header, freeing up existing buffers 3333 * in the bufqueues as necessary. The new buffer is returned locked. 3334 * 3335 * We block if: 3336 * We have insufficient buffer headers 3337 * We have insufficient buffer space 3338 * buffer_arena is too fragmented ( space reservation fails ) 3339 * If we have to flush dirty buffers ( but we try to avoid this ) 3340 * 3341 * The caller is responsible for releasing the reserved bufspace after 3342 * allocbuf() is called. 3343 */ 3344 static struct buf * 3345 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int maxsize, int gbflags) 3346 { 3347 struct bufdomain *bd; 3348 struct buf *bp; 3349 bool metadata, reserved; 3350 3351 bp = NULL; 3352 KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3353 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3354 if (!unmapped_buf_allowed) 3355 gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3356 3357 if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 || 3358 vp->v_type == VCHR) 3359 metadata = true; 3360 else 3361 metadata = false; 3362 if (vp == NULL) 3363 bd = &bdomain[0]; 3364 else 3365 bd = &bdomain[vp->v_bufobj.bo_domain]; 3366 3367 counter_u64_add(getnewbufcalls, 1); 3368 reserved = false; 3369 do { 3370 if (reserved == false && 3371 bufspace_reserve(bd, maxsize, metadata) != 0) { 3372 counter_u64_add(getnewbufrestarts, 1); 3373 continue; 3374 } 3375 reserved = true; 3376 if ((bp = buf_alloc(bd)) == NULL) { 3377 counter_u64_add(getnewbufrestarts, 1); 3378 continue; 3379 } 3380 if (getnewbuf_kva(bp, gbflags, maxsize) == 0) 3381 return (bp); 3382 break; 3383 } while (buf_recycle(bd, false) == 0); 3384 3385 if (reserved) 3386 bufspace_release(bd, maxsize); 3387 if (bp != NULL) { 3388 bp->b_flags |= B_INVAL; 3389 brelse(bp); 3390 } 3391 bufspace_wait(bd, vp, gbflags, slpflag, slptimeo); 3392 3393 return (NULL); 3394 } 3395 3396 /* 3397 * buf_daemon: 3398 * 3399 * buffer flushing daemon. Buffers are normally flushed by the 3400 * update daemon but if it cannot keep up this process starts to 3401 * take the load in an attempt to prevent getnewbuf() from blocking. 3402 */ 3403 static struct kproc_desc buf_kp = { 3404 "bufdaemon", 3405 buf_daemon, 3406 &bufdaemonproc 3407 }; 3408 SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp); 3409 3410 static int 3411 buf_flush(struct vnode *vp, struct bufdomain *bd, int target) 3412 { 3413 int flushed; 3414 3415 flushed = flushbufqueues(vp, bd, target, 0); 3416 if (flushed == 0) { 3417 /* 3418 * Could not find any buffers without rollback 3419 * dependencies, so just write the first one 3420 * in the hopes of eventually making progress. 3421 */ 3422 if (vp != NULL && target > 2) 3423 target /= 2; 3424 flushbufqueues(vp, bd, target, 1); 3425 } 3426 return (flushed); 3427 } 3428 3429 static void 3430 buf_daemon_shutdown(void *arg __unused, int howto __unused) 3431 { 3432 int error; 3433 3434 if (KERNEL_PANICKED()) 3435 return; 3436 3437 mtx_lock(&bdlock); 3438 bd_shutdown = true; 3439 wakeup(&bd_request); 3440 error = msleep(&bd_shutdown, &bdlock, 0, "buf_daemon_shutdown", 3441 60 * hz); 3442 mtx_unlock(&bdlock); 3443 if (error != 0) 3444 printf("bufdaemon wait error: %d\n", error); 3445 } 3446 3447 static void 3448 buf_daemon(void) 3449 { 3450 struct bufdomain *bd; 3451 int speedupreq; 3452 int lodirty; 3453 int i; 3454 3455 /* 3456 * This process needs to be suspended prior to shutdown sync. 3457 */ 3458 EVENTHANDLER_REGISTER(shutdown_pre_sync, buf_daemon_shutdown, NULL, 3459 SHUTDOWN_PRI_LAST + 100); 3460 3461 /* 3462 * Start the buf clean daemons as children threads. 3463 */ 3464 for (i = 0 ; i < buf_domains; i++) { 3465 int error; 3466 3467 error = kthread_add((void (*)(void *))bufspace_daemon, 3468 &bdomain[i], curproc, NULL, 0, 0, "bufspacedaemon-%d", i); 3469 if (error) 3470 panic("error %d spawning bufspace daemon", error); 3471 } 3472 3473 /* 3474 * This process is allowed to take the buffer cache to the limit 3475 */ 3476 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED; 3477 mtx_lock(&bdlock); 3478 while (!bd_shutdown) { 3479 bd_request = 0; 3480 mtx_unlock(&bdlock); 3481 3482 /* 3483 * Save speedupreq for this pass and reset to capture new 3484 * requests. 3485 */ 3486 speedupreq = bd_speedupreq; 3487 bd_speedupreq = 0; 3488 3489 /* 3490 * Flush each domain sequentially according to its level and 3491 * the speedup request. 3492 */ 3493 for (i = 0; i < buf_domains; i++) { 3494 bd = &bdomain[i]; 3495 if (speedupreq) 3496 lodirty = bd->bd_numdirtybuffers / 2; 3497 else 3498 lodirty = bd->bd_lodirtybuffers; 3499 while (bd->bd_numdirtybuffers > lodirty) { 3500 if (buf_flush(NULL, bd, 3501 bd->bd_numdirtybuffers - lodirty) == 0) 3502 break; 3503 kern_yield(PRI_USER); 3504 } 3505 } 3506 3507 /* 3508 * Only clear bd_request if we have reached our low water 3509 * mark. The buf_daemon normally waits 1 second and 3510 * then incrementally flushes any dirty buffers that have 3511 * built up, within reason. 3512 * 3513 * If we were unable to hit our low water mark and couldn't 3514 * find any flushable buffers, we sleep for a short period 3515 * to avoid endless loops on unlockable buffers. 3516 */ 3517 mtx_lock(&bdlock); 3518 if (bd_shutdown) 3519 break; 3520 if (BIT_EMPTY(BUF_DOMAINS, &bdlodirty)) { 3521 /* 3522 * We reached our low water mark, reset the 3523 * request and sleep until we are needed again. 3524 * The sleep is just so the suspend code works. 3525 */ 3526 bd_request = 0; 3527 /* 3528 * Do an extra wakeup in case dirty threshold 3529 * changed via sysctl and the explicit transition 3530 * out of shortfall was missed. 3531 */ 3532 bdirtywakeup(); 3533 if (runningbufspace <= lorunningspace) 3534 runningwakeup(); 3535 msleep(&bd_request, &bdlock, PVM, "psleep", hz); 3536 } else { 3537 /* 3538 * We couldn't find any flushable dirty buffers but 3539 * still have too many dirty buffers, we 3540 * have to sleep and try again. (rare) 3541 */ 3542 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10); 3543 } 3544 } 3545 wakeup(&bd_shutdown); 3546 mtx_unlock(&bdlock); 3547 kthread_exit(); 3548 } 3549 3550 /* 3551 * flushbufqueues: 3552 * 3553 * Try to flush a buffer in the dirty queue. We must be careful to 3554 * free up B_INVAL buffers instead of write them, which NFS is 3555 * particularly sensitive to. 3556 */ 3557 static int flushwithdeps = 0; 3558 SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW | CTLFLAG_STATS, 3559 &flushwithdeps, 0, 3560 "Number of buffers flushed with dependencies that require rollbacks"); 3561 3562 static int 3563 flushbufqueues(struct vnode *lvp, struct bufdomain *bd, int target, 3564 int flushdeps) 3565 { 3566 struct bufqueue *bq; 3567 struct buf *sentinel; 3568 struct vnode *vp; 3569 struct mount *mp; 3570 struct buf *bp; 3571 int hasdeps; 3572 int flushed; 3573 int error; 3574 bool unlock; 3575 3576 flushed = 0; 3577 bq = &bd->bd_dirtyq; 3578 bp = NULL; 3579 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO); 3580 sentinel->b_qindex = QUEUE_SENTINEL; 3581 BQ_LOCK(bq); 3582 TAILQ_INSERT_HEAD(&bq->bq_queue, sentinel, b_freelist); 3583 BQ_UNLOCK(bq); 3584 while (flushed != target) { 3585 maybe_yield(); 3586 BQ_LOCK(bq); 3587 bp = TAILQ_NEXT(sentinel, b_freelist); 3588 if (bp != NULL) { 3589 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3590 TAILQ_INSERT_AFTER(&bq->bq_queue, bp, sentinel, 3591 b_freelist); 3592 } else { 3593 BQ_UNLOCK(bq); 3594 break; 3595 } 3596 /* 3597 * Skip sentinels inserted by other invocations of the 3598 * flushbufqueues(), taking care to not reorder them. 3599 * 3600 * Only flush the buffers that belong to the 3601 * vnode locked by the curthread. 3602 */ 3603 if (bp->b_qindex == QUEUE_SENTINEL || (lvp != NULL && 3604 bp->b_vp != lvp)) { 3605 BQ_UNLOCK(bq); 3606 continue; 3607 } 3608 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 3609 BQ_UNLOCK(bq); 3610 if (error != 0) 3611 continue; 3612 3613 /* 3614 * BKGRDINPROG can only be set with the buf and bufobj 3615 * locks both held. We tolerate a race to clear it here. 3616 */ 3617 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 || 3618 (bp->b_flags & B_DELWRI) == 0) { 3619 BUF_UNLOCK(bp); 3620 continue; 3621 } 3622 if (bp->b_flags & B_INVAL) { 3623 bremfreef(bp); 3624 brelse(bp); 3625 flushed++; 3626 continue; 3627 } 3628 3629 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) { 3630 if (flushdeps == 0) { 3631 BUF_UNLOCK(bp); 3632 continue; 3633 } 3634 hasdeps = 1; 3635 } else 3636 hasdeps = 0; 3637 /* 3638 * We must hold the lock on a vnode before writing 3639 * one of its buffers. Otherwise we may confuse, or 3640 * in the case of a snapshot vnode, deadlock the 3641 * system. 3642 * 3643 * The lock order here is the reverse of the normal 3644 * of vnode followed by buf lock. This is ok because 3645 * the NOWAIT will prevent deadlock. 3646 */ 3647 vp = bp->b_vp; 3648 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { 3649 BUF_UNLOCK(bp); 3650 continue; 3651 } 3652 if (lvp == NULL) { 3653 unlock = true; 3654 error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); 3655 } else { 3656 ASSERT_VOP_LOCKED(vp, "getbuf"); 3657 unlock = false; 3658 error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : 3659 vn_lock(vp, LK_TRYUPGRADE); 3660 } 3661 if (error == 0) { 3662 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", 3663 bp, bp->b_vp, bp->b_flags); 3664 if (curproc == bufdaemonproc) { 3665 vfs_bio_awrite(bp); 3666 } else { 3667 bremfree(bp); 3668 bwrite(bp); 3669 counter_u64_add(notbufdflushes, 1); 3670 } 3671 vn_finished_write(mp); 3672 if (unlock) 3673 VOP_UNLOCK(vp); 3674 flushwithdeps += hasdeps; 3675 flushed++; 3676 3677 /* 3678 * Sleeping on runningbufspace while holding 3679 * vnode lock leads to deadlock. 3680 */ 3681 if (curproc == bufdaemonproc && 3682 runningbufspace > hirunningspace) 3683 waitrunningbufspace(); 3684 continue; 3685 } 3686 vn_finished_write(mp); 3687 BUF_UNLOCK(bp); 3688 } 3689 BQ_LOCK(bq); 3690 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3691 BQ_UNLOCK(bq); 3692 free(sentinel, M_TEMP); 3693 return (flushed); 3694 } 3695 3696 /* 3697 * Check to see if a block is currently memory resident. 3698 */ 3699 struct buf * 3700 incore(struct bufobj *bo, daddr_t blkno) 3701 { 3702 return (gbincore_unlocked(bo, blkno)); 3703 } 3704 3705 /* 3706 * Returns true if no I/O is needed to access the 3707 * associated VM object. This is like incore except 3708 * it also hunts around in the VM system for the data. 3709 */ 3710 bool 3711 inmem(struct vnode * vp, daddr_t blkno) 3712 { 3713 vm_object_t obj; 3714 vm_offset_t toff, tinc, size; 3715 vm_page_t m, n; 3716 vm_ooffset_t off; 3717 int valid; 3718 3719 ASSERT_VOP_LOCKED(vp, "inmem"); 3720 3721 if (incore(&vp->v_bufobj, blkno)) 3722 return (true); 3723 if (vp->v_mount == NULL) 3724 return (false); 3725 obj = vp->v_object; 3726 if (obj == NULL) 3727 return (false); 3728 3729 size = PAGE_SIZE; 3730 if (size > vp->v_mount->mnt_stat.f_iosize) 3731 size = vp->v_mount->mnt_stat.f_iosize; 3732 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 3733 3734 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 3735 m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3736 recheck: 3737 if (m == NULL) 3738 return (false); 3739 3740 tinc = size; 3741 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 3742 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 3743 /* 3744 * Consider page validity only if page mapping didn't change 3745 * during the check. 3746 */ 3747 valid = vm_page_is_valid(m, 3748 (vm_offset_t)((toff + off) & PAGE_MASK), tinc); 3749 n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3750 if (m != n) { 3751 m = n; 3752 goto recheck; 3753 } 3754 if (!valid) 3755 return (false); 3756 } 3757 return (true); 3758 } 3759 3760 /* 3761 * Set the dirty range for a buffer based on the status of the dirty 3762 * bits in the pages comprising the buffer. The range is limited 3763 * to the size of the buffer. 3764 * 3765 * Tell the VM system that the pages associated with this buffer 3766 * are clean. This is used for delayed writes where the data is 3767 * going to go to disk eventually without additional VM intevention. 3768 * 3769 * Note that while we only really need to clean through to b_bcount, we 3770 * just go ahead and clean through to b_bufsize. 3771 */ 3772 static void 3773 vfs_clean_pages_dirty_buf(struct buf *bp) 3774 { 3775 vm_ooffset_t foff, noff, eoff; 3776 vm_page_t m; 3777 int i; 3778 3779 if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0) 3780 return; 3781 3782 foff = bp->b_offset; 3783 KASSERT(bp->b_offset != NOOFFSET, 3784 ("vfs_clean_pages_dirty_buf: no buffer offset")); 3785 3786 vfs_busy_pages_acquire(bp); 3787 vfs_setdirty_range(bp); 3788 for (i = 0; i < bp->b_npages; i++) { 3789 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3790 eoff = noff; 3791 if (eoff > bp->b_offset + bp->b_bufsize) 3792 eoff = bp->b_offset + bp->b_bufsize; 3793 m = bp->b_pages[i]; 3794 vfs_page_set_validclean(bp, foff, m); 3795 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */ 3796 foff = noff; 3797 } 3798 vfs_busy_pages_release(bp); 3799 } 3800 3801 static void 3802 vfs_setdirty_range(struct buf *bp) 3803 { 3804 vm_offset_t boffset; 3805 vm_offset_t eoffset; 3806 int i; 3807 3808 /* 3809 * test the pages to see if they have been modified directly 3810 * by users through the VM system. 3811 */ 3812 for (i = 0; i < bp->b_npages; i++) 3813 vm_page_test_dirty(bp->b_pages[i]); 3814 3815 /* 3816 * Calculate the encompassing dirty range, boffset and eoffset, 3817 * (eoffset - boffset) bytes. 3818 */ 3819 3820 for (i = 0; i < bp->b_npages; i++) { 3821 if (bp->b_pages[i]->dirty) 3822 break; 3823 } 3824 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3825 3826 for (i = bp->b_npages - 1; i >= 0; --i) { 3827 if (bp->b_pages[i]->dirty) { 3828 break; 3829 } 3830 } 3831 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3832 3833 /* 3834 * Fit it to the buffer. 3835 */ 3836 3837 if (eoffset > bp->b_bcount) 3838 eoffset = bp->b_bcount; 3839 3840 /* 3841 * If we have a good dirty range, merge with the existing 3842 * dirty range. 3843 */ 3844 3845 if (boffset < eoffset) { 3846 if (bp->b_dirtyoff > boffset) 3847 bp->b_dirtyoff = boffset; 3848 if (bp->b_dirtyend < eoffset) 3849 bp->b_dirtyend = eoffset; 3850 } 3851 } 3852 3853 /* 3854 * Allocate the KVA mapping for an existing buffer. 3855 * If an unmapped buffer is provided but a mapped buffer is requested, take 3856 * also care to properly setup mappings between pages and KVA. 3857 */ 3858 static void 3859 bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags) 3860 { 3861 int bsize, maxsize, need_mapping, need_kva; 3862 off_t offset; 3863 3864 need_mapping = bp->b_data == unmapped_buf && 3865 (gbflags & GB_UNMAPPED) == 0; 3866 need_kva = bp->b_kvabase == unmapped_buf && 3867 bp->b_data == unmapped_buf && 3868 (gbflags & GB_KVAALLOC) != 0; 3869 if (!need_mapping && !need_kva) 3870 return; 3871 3872 BUF_CHECK_UNMAPPED(bp); 3873 3874 if (need_mapping && bp->b_kvabase != unmapped_buf) { 3875 /* 3876 * Buffer is not mapped, but the KVA was already 3877 * reserved at the time of the instantiation. Use the 3878 * allocated space. 3879 */ 3880 goto has_addr; 3881 } 3882 3883 /* 3884 * Calculate the amount of the address space we would reserve 3885 * if the buffer was mapped. 3886 */ 3887 bsize = vn_isdisk(bp->b_vp) ? DEV_BSIZE : bp->b_bufobj->bo_bsize; 3888 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 3889 offset = blkno * bsize; 3890 maxsize = size + (offset & PAGE_MASK); 3891 maxsize = imax(maxsize, bsize); 3892 3893 while (bufkva_alloc(bp, maxsize, gbflags) != 0) { 3894 if ((gbflags & GB_NOWAIT_BD) != 0) { 3895 /* 3896 * XXXKIB: defragmentation cannot 3897 * succeed, not sure what else to do. 3898 */ 3899 panic("GB_NOWAIT_BD and GB_UNMAPPED %p", bp); 3900 } 3901 counter_u64_add(mappingrestarts, 1); 3902 bufspace_wait(bufdomain(bp), bp->b_vp, gbflags, 0, 0); 3903 } 3904 has_addr: 3905 if (need_mapping) { 3906 /* b_offset is handled by bpmap_qenter. */ 3907 bp->b_data = bp->b_kvabase; 3908 BUF_CHECK_MAPPED(bp); 3909 bpmap_qenter(bp); 3910 } 3911 } 3912 3913 struct buf * 3914 getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo, 3915 int flags) 3916 { 3917 struct buf *bp; 3918 int error; 3919 3920 error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp); 3921 if (error != 0) 3922 return (NULL); 3923 return (bp); 3924 } 3925 3926 /* 3927 * getblkx: 3928 * 3929 * Get a block given a specified block and offset into a file/device. 3930 * The buffers B_DONE bit will be cleared on return, making it almost 3931 * ready for an I/O initiation. B_INVAL may or may not be set on 3932 * return. The caller should clear B_INVAL prior to initiating a 3933 * READ. 3934 * 3935 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for 3936 * an existing buffer. 3937 * 3938 * For a VMIO buffer, B_CACHE is modified according to the backing VM. 3939 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set 3940 * and then cleared based on the backing VM. If the previous buffer is 3941 * non-0-sized but invalid, B_CACHE will be cleared. 3942 * 3943 * If getblk() must create a new buffer, the new buffer is returned with 3944 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which 3945 * case it is returned with B_INVAL clear and B_CACHE set based on the 3946 * backing VM. 3947 * 3948 * getblk() also forces a bwrite() for any B_DELWRI buffer whose 3949 * B_CACHE bit is clear. 3950 * 3951 * What this means, basically, is that the caller should use B_CACHE to 3952 * determine whether the buffer is fully valid or not and should clear 3953 * B_INVAL prior to issuing a read. If the caller intends to validate 3954 * the buffer by loading its data area with something, the caller needs 3955 * to clear B_INVAL. If the caller does this without issuing an I/O, 3956 * the caller should set B_CACHE ( as an optimization ), else the caller 3957 * should issue the I/O and biodone() will set B_CACHE if the I/O was 3958 * a write attempt or if it was a successful read. If the caller 3959 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR 3960 * prior to issuing the READ. biodone() will *not* clear B_INVAL. 3961 * 3962 * The blkno parameter is the logical block being requested. Normally 3963 * the mapping of logical block number to disk block address is done 3964 * by calling VOP_BMAP(). However, if the mapping is already known, the 3965 * disk block address can be passed using the dblkno parameter. If the 3966 * disk block address is not known, then the same value should be passed 3967 * for blkno and dblkno. 3968 */ 3969 int 3970 getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag, 3971 int slptimeo, int flags, struct buf **bpp) 3972 { 3973 struct buf *bp; 3974 struct bufobj *bo; 3975 daddr_t d_blkno; 3976 int bsize, error, maxsize, vmio; 3977 off_t offset; 3978 3979 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size); 3980 KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3981 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3982 if (vp->v_type != VCHR) 3983 ASSERT_VOP_LOCKED(vp, "getblk"); 3984 if (size > maxbcachebuf) 3985 panic("getblk: size(%d) > maxbcachebuf(%d)\n", size, 3986 maxbcachebuf); 3987 if (!unmapped_buf_allowed) 3988 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3989 3990 bo = &vp->v_bufobj; 3991 d_blkno = dblkno; 3992 3993 /* Attempt lockless lookup first. */ 3994 bp = gbincore_unlocked(bo, blkno); 3995 if (bp == NULL) { 3996 /* 3997 * With GB_NOCREAT we must be sure about not finding the buffer 3998 * as it may have been reassigned during unlocked lookup. 3999 */ 4000 if ((flags & GB_NOCREAT) != 0) 4001 goto loop; 4002 goto newbuf_unlocked; 4003 } 4004 4005 error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL, "getblku", 0, 4006 0); 4007 if (error != 0) 4008 goto loop; 4009 4010 /* Verify buf identify has not changed since lookup. */ 4011 if (bp->b_bufobj == bo && bp->b_lblkno == blkno) 4012 goto foundbuf_fastpath; 4013 4014 /* It changed, fallback to locked lookup. */ 4015 BUF_UNLOCK_RAW(bp); 4016 4017 loop: 4018 BO_RLOCK(bo); 4019 bp = gbincore(bo, blkno); 4020 if (bp != NULL) { 4021 int lockflags; 4022 4023 /* 4024 * Buffer is in-core. If the buffer is not busy nor managed, 4025 * it must be on a queue. 4026 */ 4027 lockflags = LK_EXCLUSIVE | LK_INTERLOCK | 4028 ((flags & GB_LOCK_NOWAIT) != 0 ? LK_NOWAIT : LK_SLEEPFAIL); 4029 #ifdef WITNESS 4030 lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0; 4031 #endif 4032 4033 error = BUF_TIMELOCK(bp, lockflags, 4034 BO_LOCKPTR(bo), "getblk", slpflag, slptimeo); 4035 4036 /* 4037 * If we slept and got the lock we have to restart in case 4038 * the buffer changed identities. 4039 */ 4040 if (error == ENOLCK) 4041 goto loop; 4042 /* We timed out or were interrupted. */ 4043 else if (error != 0) 4044 return (error); 4045 4046 foundbuf_fastpath: 4047 /* If recursed, assume caller knows the rules. */ 4048 if (BUF_LOCKRECURSED(bp)) 4049 goto end; 4050 4051 /* 4052 * The buffer is locked. B_CACHE is cleared if the buffer is 4053 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set 4054 * and for a VMIO buffer B_CACHE is adjusted according to the 4055 * backing VM cache. 4056 */ 4057 if (bp->b_flags & B_INVAL) 4058 bp->b_flags &= ~B_CACHE; 4059 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0) 4060 bp->b_flags |= B_CACHE; 4061 if (bp->b_flags & B_MANAGED) 4062 MPASS(bp->b_qindex == QUEUE_NONE); 4063 else 4064 bremfree(bp); 4065 4066 /* 4067 * check for size inconsistencies for non-VMIO case. 4068 */ 4069 if (bp->b_bcount != size) { 4070 if ((bp->b_flags & B_VMIO) == 0 || 4071 (size > bp->b_kvasize)) { 4072 if (bp->b_flags & B_DELWRI) { 4073 bp->b_flags |= B_NOCACHE; 4074 bwrite(bp); 4075 } else { 4076 if (LIST_EMPTY(&bp->b_dep)) { 4077 bp->b_flags |= B_RELBUF; 4078 brelse(bp); 4079 } else { 4080 bp->b_flags |= B_NOCACHE; 4081 bwrite(bp); 4082 } 4083 } 4084 goto loop; 4085 } 4086 } 4087 4088 /* 4089 * Handle the case of unmapped buffer which should 4090 * become mapped, or the buffer for which KVA 4091 * reservation is requested. 4092 */ 4093 bp_unmapped_get_kva(bp, blkno, size, flags); 4094 4095 /* 4096 * If the size is inconsistent in the VMIO case, we can resize 4097 * the buffer. This might lead to B_CACHE getting set or 4098 * cleared. If the size has not changed, B_CACHE remains 4099 * unchanged from its previous state. 4100 */ 4101 allocbuf(bp, size); 4102 4103 KASSERT(bp->b_offset != NOOFFSET, 4104 ("getblk: no buffer offset")); 4105 4106 /* 4107 * A buffer with B_DELWRI set and B_CACHE clear must 4108 * be committed before we can return the buffer in 4109 * order to prevent the caller from issuing a read 4110 * ( due to B_CACHE not being set ) and overwriting 4111 * it. 4112 * 4113 * Most callers, including NFS and FFS, need this to 4114 * operate properly either because they assume they 4115 * can issue a read if B_CACHE is not set, or because 4116 * ( for example ) an uncached B_DELWRI might loop due 4117 * to softupdates re-dirtying the buffer. In the latter 4118 * case, B_CACHE is set after the first write completes, 4119 * preventing further loops. 4120 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE 4121 * above while extending the buffer, we cannot allow the 4122 * buffer to remain with B_CACHE set after the write 4123 * completes or it will represent a corrupt state. To 4124 * deal with this we set B_NOCACHE to scrap the buffer 4125 * after the write. 4126 * 4127 * We might be able to do something fancy, like setting 4128 * B_CACHE in bwrite() except if B_DELWRI is already set, 4129 * so the below call doesn't set B_CACHE, but that gets real 4130 * confusing. This is much easier. 4131 */ 4132 4133 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) { 4134 bp->b_flags |= B_NOCACHE; 4135 bwrite(bp); 4136 goto loop; 4137 } 4138 bp->b_flags &= ~B_DONE; 4139 } else { 4140 /* 4141 * Buffer is not in-core, create new buffer. The buffer 4142 * returned by getnewbuf() is locked. Note that the returned 4143 * buffer is also considered valid (not marked B_INVAL). 4144 */ 4145 BO_RUNLOCK(bo); 4146 newbuf_unlocked: 4147 /* 4148 * If the user does not want us to create the buffer, bail out 4149 * here. 4150 */ 4151 if (flags & GB_NOCREAT) 4152 return (EEXIST); 4153 4154 bsize = vn_isdisk(vp) ? DEV_BSIZE : bo->bo_bsize; 4155 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 4156 offset = blkno * bsize; 4157 vmio = vp->v_object != NULL; 4158 if (vmio) { 4159 maxsize = size + (offset & PAGE_MASK); 4160 } else { 4161 maxsize = size; 4162 /* Do not allow non-VMIO notmapped buffers. */ 4163 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 4164 } 4165 maxsize = imax(maxsize, bsize); 4166 if ((flags & GB_NOSPARSE) != 0 && vmio && 4167 !vn_isdisk(vp)) { 4168 error = VOP_BMAP(vp, blkno, NULL, &d_blkno, 0, 0); 4169 KASSERT(error != EOPNOTSUPP, 4170 ("GB_NOSPARSE from fs not supporting bmap, vp %p", 4171 vp)); 4172 if (error != 0) 4173 return (error); 4174 if (d_blkno == -1) 4175 return (EJUSTRETURN); 4176 } 4177 4178 bp = getnewbuf(vp, slpflag, slptimeo, maxsize, flags); 4179 if (bp == NULL) { 4180 if (slpflag || slptimeo) 4181 return (ETIMEDOUT); 4182 /* 4183 * XXX This is here until the sleep path is diagnosed 4184 * enough to work under very low memory conditions. 4185 * 4186 * There's an issue on low memory, 4BSD+non-preempt 4187 * systems (eg MIPS routers with 32MB RAM) where buffer 4188 * exhaustion occurs without sleeping for buffer 4189 * reclaimation. This just sticks in a loop and 4190 * constantly attempts to allocate a buffer, which 4191 * hits exhaustion and tries to wakeup bufdaemon. 4192 * This never happens because we never yield. 4193 * 4194 * The real solution is to identify and fix these cases 4195 * so we aren't effectively busy-waiting in a loop 4196 * until the reclaimation path has cycles to run. 4197 */ 4198 kern_yield(PRI_USER); 4199 goto loop; 4200 } 4201 4202 /* 4203 * This code is used to make sure that a buffer is not 4204 * created while the getnewbuf routine is blocked. 4205 * This can be a problem whether the vnode is locked or not. 4206 * If the buffer is created out from under us, we have to 4207 * throw away the one we just created. 4208 * 4209 * Note: this must occur before we associate the buffer 4210 * with the vp especially considering limitations in 4211 * the splay tree implementation when dealing with duplicate 4212 * lblkno's. 4213 */ 4214 BO_LOCK(bo); 4215 if (gbincore(bo, blkno)) { 4216 BO_UNLOCK(bo); 4217 bp->b_flags |= B_INVAL; 4218 bufspace_release(bufdomain(bp), maxsize); 4219 brelse(bp); 4220 goto loop; 4221 } 4222 4223 /* 4224 * Insert the buffer into the hash, so that it can 4225 * be found by incore. 4226 */ 4227 bp->b_lblkno = blkno; 4228 bp->b_blkno = d_blkno; 4229 bp->b_offset = offset; 4230 bgetvp(vp, bp); 4231 BO_UNLOCK(bo); 4232 4233 /* 4234 * set B_VMIO bit. allocbuf() the buffer bigger. Since the 4235 * buffer size starts out as 0, B_CACHE will be set by 4236 * allocbuf() for the VMIO case prior to it testing the 4237 * backing store for validity. 4238 */ 4239 4240 if (vmio) { 4241 bp->b_flags |= B_VMIO; 4242 KASSERT(vp->v_object == bp->b_bufobj->bo_object, 4243 ("ARGH! different b_bufobj->bo_object %p %p %p\n", 4244 bp, vp->v_object, bp->b_bufobj->bo_object)); 4245 } else { 4246 bp->b_flags &= ~B_VMIO; 4247 KASSERT(bp->b_bufobj->bo_object == NULL, 4248 ("ARGH! has b_bufobj->bo_object %p %p\n", 4249 bp, bp->b_bufobj->bo_object)); 4250 BUF_CHECK_MAPPED(bp); 4251 } 4252 4253 allocbuf(bp, size); 4254 bufspace_release(bufdomain(bp), maxsize); 4255 bp->b_flags &= ~B_DONE; 4256 } 4257 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp); 4258 end: 4259 buf_track(bp, __func__); 4260 KASSERT(bp->b_bufobj == bo, 4261 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo)); 4262 *bpp = bp; 4263 return (0); 4264 } 4265 4266 /* 4267 * Get an empty, disassociated buffer of given size. The buffer is initially 4268 * set to B_INVAL. 4269 */ 4270 struct buf * 4271 geteblk(int size, int flags) 4272 { 4273 struct buf *bp; 4274 int maxsize; 4275 4276 maxsize = (size + BKVAMASK) & ~BKVAMASK; 4277 while ((bp = getnewbuf(NULL, 0, 0, maxsize, flags)) == NULL) { 4278 if ((flags & GB_NOWAIT_BD) && 4279 (curthread->td_pflags & TDP_BUFNEED) != 0) 4280 return (NULL); 4281 } 4282 allocbuf(bp, size); 4283 bufspace_release(bufdomain(bp), maxsize); 4284 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 4285 return (bp); 4286 } 4287 4288 /* 4289 * Truncate the backing store for a non-vmio buffer. 4290 */ 4291 static void 4292 vfs_nonvmio_truncate(struct buf *bp, int newbsize) 4293 { 4294 4295 if (bp->b_flags & B_MALLOC) { 4296 /* 4297 * malloced buffers are not shrunk 4298 */ 4299 if (newbsize == 0) { 4300 bufmallocadjust(bp, 0); 4301 free(bp->b_data, M_BIOBUF); 4302 bp->b_data = bp->b_kvabase; 4303 bp->b_flags &= ~B_MALLOC; 4304 } 4305 return; 4306 } 4307 vm_hold_free_pages(bp, newbsize); 4308 bufspace_adjust(bp, newbsize); 4309 } 4310 4311 /* 4312 * Extend the backing for a non-VMIO buffer. 4313 */ 4314 static void 4315 vfs_nonvmio_extend(struct buf *bp, int newbsize) 4316 { 4317 caddr_t origbuf; 4318 int origbufsize; 4319 4320 /* 4321 * We only use malloced memory on the first allocation. 4322 * and revert to page-allocated memory when the buffer 4323 * grows. 4324 * 4325 * There is a potential smp race here that could lead 4326 * to bufmallocspace slightly passing the max. It 4327 * is probably extremely rare and not worth worrying 4328 * over. 4329 */ 4330 if (bp->b_bufsize == 0 && newbsize <= PAGE_SIZE/2 && 4331 bufmallocspace < maxbufmallocspace) { 4332 bp->b_data = malloc(newbsize, M_BIOBUF, M_WAITOK); 4333 bp->b_flags |= B_MALLOC; 4334 bufmallocadjust(bp, newbsize); 4335 return; 4336 } 4337 4338 /* 4339 * If the buffer is growing on its other-than-first 4340 * allocation then we revert to the page-allocation 4341 * scheme. 4342 */ 4343 origbuf = NULL; 4344 origbufsize = 0; 4345 if (bp->b_flags & B_MALLOC) { 4346 origbuf = bp->b_data; 4347 origbufsize = bp->b_bufsize; 4348 bp->b_data = bp->b_kvabase; 4349 bufmallocadjust(bp, 0); 4350 bp->b_flags &= ~B_MALLOC; 4351 newbsize = round_page(newbsize); 4352 } 4353 vm_hold_load_pages(bp, (vm_offset_t) bp->b_data + bp->b_bufsize, 4354 (vm_offset_t) bp->b_data + newbsize); 4355 if (origbuf != NULL) { 4356 bcopy(origbuf, bp->b_data, origbufsize); 4357 free(origbuf, M_BIOBUF); 4358 } 4359 bufspace_adjust(bp, newbsize); 4360 } 4361 4362 /* 4363 * This code constitutes the buffer memory from either anonymous system 4364 * memory (in the case of non-VMIO operations) or from an associated 4365 * VM object (in the case of VMIO operations). This code is able to 4366 * resize a buffer up or down. 4367 * 4368 * Note that this code is tricky, and has many complications to resolve 4369 * deadlock or inconsistent data situations. Tread lightly!!! 4370 * There are B_CACHE and B_DELWRI interactions that must be dealt with by 4371 * the caller. Calling this code willy nilly can result in the loss of data. 4372 * 4373 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with 4374 * B_CACHE for the non-VMIO case. 4375 */ 4376 int 4377 allocbuf(struct buf *bp, int size) 4378 { 4379 int newbsize; 4380 4381 if (bp->b_bcount == size) 4382 return (1); 4383 4384 KASSERT(bp->b_kvasize == 0 || bp->b_kvasize >= size, 4385 ("allocbuf: buffer too small %p %#x %#x", 4386 bp, bp->b_kvasize, size)); 4387 4388 newbsize = roundup2(size, DEV_BSIZE); 4389 if ((bp->b_flags & B_VMIO) == 0) { 4390 if ((bp->b_flags & B_MALLOC) == 0) 4391 newbsize = round_page(newbsize); 4392 /* 4393 * Just get anonymous memory from the kernel. Don't 4394 * mess with B_CACHE. 4395 */ 4396 if (newbsize < bp->b_bufsize) 4397 vfs_nonvmio_truncate(bp, newbsize); 4398 else if (newbsize > bp->b_bufsize) 4399 vfs_nonvmio_extend(bp, newbsize); 4400 } else { 4401 int desiredpages; 4402 4403 desiredpages = size == 0 ? 0 : 4404 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 4405 4406 KASSERT((bp->b_flags & B_MALLOC) == 0, 4407 ("allocbuf: VMIO buffer can't be malloced %p", bp)); 4408 4409 /* 4410 * Set B_CACHE initially if buffer is 0 length or will become 4411 * 0-length. 4412 */ 4413 if (size == 0 || bp->b_bufsize == 0) 4414 bp->b_flags |= B_CACHE; 4415 4416 if (newbsize < bp->b_bufsize) 4417 vfs_vmio_truncate(bp, desiredpages); 4418 /* XXX This looks as if it should be newbsize > b_bufsize */ 4419 else if (size > bp->b_bcount) 4420 vfs_vmio_extend(bp, desiredpages, size); 4421 bufspace_adjust(bp, newbsize); 4422 } 4423 bp->b_bcount = size; /* requested buffer size. */ 4424 return (1); 4425 } 4426 4427 extern int inflight_transient_maps; 4428 4429 static struct bio_queue nondump_bios; 4430 4431 void 4432 biodone(struct bio *bp) 4433 { 4434 struct mtx *mtxp; 4435 void (*done)(struct bio *); 4436 vm_offset_t start, end; 4437 4438 biotrack(bp, __func__); 4439 4440 /* 4441 * Avoid completing I/O when dumping after a panic since that may 4442 * result in a deadlock in the filesystem or pager code. Note that 4443 * this doesn't affect dumps that were started manually since we aim 4444 * to keep the system usable after it has been resumed. 4445 */ 4446 if (__predict_false(dumping && SCHEDULER_STOPPED())) { 4447 TAILQ_INSERT_HEAD(&nondump_bios, bp, bio_queue); 4448 return; 4449 } 4450 if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { 4451 bp->bio_flags &= ~BIO_TRANSIENT_MAPPING; 4452 bp->bio_flags |= BIO_UNMAPPED; 4453 start = trunc_page((vm_offset_t)bp->bio_data); 4454 end = round_page((vm_offset_t)bp->bio_data + bp->bio_length); 4455 bp->bio_data = unmapped_buf; 4456 pmap_qremove(start, atop(end - start)); 4457 vmem_free(transient_arena, start, end - start); 4458 atomic_add_int(&inflight_transient_maps, -1); 4459 } 4460 done = bp->bio_done; 4461 /* 4462 * The check for done == biodone is to allow biodone to be 4463 * used as a bio_done routine. 4464 */ 4465 if (done == NULL || done == biodone) { 4466 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4467 mtx_lock(mtxp); 4468 bp->bio_flags |= BIO_DONE; 4469 wakeup(bp); 4470 mtx_unlock(mtxp); 4471 } else 4472 done(bp); 4473 } 4474 4475 /* 4476 * Wait for a BIO to finish. 4477 */ 4478 int 4479 biowait(struct bio *bp, const char *wmesg) 4480 { 4481 struct mtx *mtxp; 4482 4483 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4484 mtx_lock(mtxp); 4485 while ((bp->bio_flags & BIO_DONE) == 0) 4486 msleep(bp, mtxp, PRIBIO, wmesg, 0); 4487 mtx_unlock(mtxp); 4488 if (bp->bio_error != 0) 4489 return (bp->bio_error); 4490 if (!(bp->bio_flags & BIO_ERROR)) 4491 return (0); 4492 return (EIO); 4493 } 4494 4495 void 4496 biofinish(struct bio *bp, struct devstat *stat, int error) 4497 { 4498 4499 if (error) { 4500 bp->bio_error = error; 4501 bp->bio_flags |= BIO_ERROR; 4502 } 4503 if (stat != NULL) 4504 devstat_end_transaction_bio(stat, bp); 4505 biodone(bp); 4506 } 4507 4508 #if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING) 4509 void 4510 biotrack_buf(struct bio *bp, const char *location) 4511 { 4512 4513 buf_track(bp->bio_track_bp, location); 4514 } 4515 #endif 4516 4517 /* 4518 * bufwait: 4519 * 4520 * Wait for buffer I/O completion, returning error status. The buffer 4521 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR 4522 * error and cleared. 4523 */ 4524 int 4525 bufwait(struct buf *bp) 4526 { 4527 if (bp->b_iocmd == BIO_READ) 4528 bwait(bp, PRIBIO, "biord"); 4529 else 4530 bwait(bp, PRIBIO, "biowr"); 4531 if (bp->b_flags & B_EINTR) { 4532 bp->b_flags &= ~B_EINTR; 4533 return (EINTR); 4534 } 4535 if (bp->b_ioflags & BIO_ERROR) { 4536 return (bp->b_error ? bp->b_error : EIO); 4537 } else { 4538 return (0); 4539 } 4540 } 4541 4542 /* 4543 * bufdone: 4544 * 4545 * Finish I/O on a buffer, optionally calling a completion function. 4546 * This is usually called from an interrupt so process blocking is 4547 * not allowed. 4548 * 4549 * biodone is also responsible for setting B_CACHE in a B_VMIO bp. 4550 * In a non-VMIO bp, B_CACHE will be set on the next getblk() 4551 * assuming B_INVAL is clear. 4552 * 4553 * For the VMIO case, we set B_CACHE if the op was a read and no 4554 * read error occurred, or if the op was a write. B_CACHE is never 4555 * set if the buffer is invalid or otherwise uncacheable. 4556 * 4557 * bufdone does not mess with B_INVAL, allowing the I/O routine or the 4558 * initiator to leave B_INVAL set to brelse the buffer out of existence 4559 * in the biodone routine. 4560 */ 4561 void 4562 bufdone(struct buf *bp) 4563 { 4564 struct bufobj *dropobj; 4565 void (*biodone)(struct buf *); 4566 4567 buf_track(bp, __func__); 4568 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 4569 dropobj = NULL; 4570 4571 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp)); 4572 4573 runningbufwakeup(bp); 4574 if (bp->b_iocmd == BIO_WRITE) 4575 dropobj = bp->b_bufobj; 4576 /* call optional completion function if requested */ 4577 if (bp->b_iodone != NULL) { 4578 biodone = bp->b_iodone; 4579 bp->b_iodone = NULL; 4580 (*biodone) (bp); 4581 if (dropobj) 4582 bufobj_wdrop(dropobj); 4583 return; 4584 } 4585 if (bp->b_flags & B_VMIO) { 4586 /* 4587 * Set B_CACHE if the op was a normal read and no error 4588 * occurred. B_CACHE is set for writes in the b*write() 4589 * routines. 4590 */ 4591 if (bp->b_iocmd == BIO_READ && 4592 !(bp->b_flags & (B_INVAL|B_NOCACHE)) && 4593 !(bp->b_ioflags & BIO_ERROR)) 4594 bp->b_flags |= B_CACHE; 4595 vfs_vmio_iodone(bp); 4596 } 4597 if (!LIST_EMPTY(&bp->b_dep)) 4598 buf_complete(bp); 4599 if ((bp->b_flags & B_CKHASH) != 0) { 4600 KASSERT(bp->b_iocmd == BIO_READ, 4601 ("bufdone: b_iocmd %d not BIO_READ", bp->b_iocmd)); 4602 KASSERT(buf_mapped(bp), ("bufdone: bp %p not mapped", bp)); 4603 (*bp->b_ckhashcalc)(bp); 4604 } 4605 /* 4606 * For asynchronous completions, release the buffer now. The brelse 4607 * will do a wakeup there if necessary - so no need to do a wakeup 4608 * here in the async case. The sync case always needs to do a wakeup. 4609 */ 4610 if (bp->b_flags & B_ASYNC) { 4611 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || 4612 (bp->b_ioflags & BIO_ERROR)) 4613 brelse(bp); 4614 else 4615 bqrelse(bp); 4616 } else 4617 bdone(bp); 4618 if (dropobj) 4619 bufobj_wdrop(dropobj); 4620 } 4621 4622 /* 4623 * This routine is called in lieu of iodone in the case of 4624 * incomplete I/O. This keeps the busy status for pages 4625 * consistent. 4626 */ 4627 void 4628 vfs_unbusy_pages(struct buf *bp) 4629 { 4630 int i; 4631 vm_object_t obj; 4632 vm_page_t m; 4633 4634 runningbufwakeup(bp); 4635 if (!(bp->b_flags & B_VMIO)) 4636 return; 4637 4638 obj = bp->b_bufobj->bo_object; 4639 for (i = 0; i < bp->b_npages; i++) { 4640 m = bp->b_pages[i]; 4641 if (m == bogus_page) { 4642 m = vm_page_relookup(obj, OFF_TO_IDX(bp->b_offset) + i); 4643 if (!m) 4644 panic("vfs_unbusy_pages: page missing\n"); 4645 bp->b_pages[i] = m; 4646 if (buf_mapped(bp)) { 4647 BUF_CHECK_MAPPED(bp); 4648 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4649 bp->b_pages, bp->b_npages); 4650 } else 4651 BUF_CHECK_UNMAPPED(bp); 4652 } 4653 vm_page_sunbusy(m); 4654 } 4655 vm_object_pip_wakeupn(obj, bp->b_npages); 4656 } 4657 4658 /* 4659 * vfs_page_set_valid: 4660 * 4661 * Set the valid bits in a page based on the supplied offset. The 4662 * range is restricted to the buffer's size. 4663 * 4664 * This routine is typically called after a read completes. 4665 */ 4666 static void 4667 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4668 { 4669 vm_ooffset_t eoff; 4670 4671 /* 4672 * Compute the end offset, eoff, such that [off, eoff) does not span a 4673 * page boundary and eoff is not greater than the end of the buffer. 4674 * The end of the buffer, in this case, is our file EOF, not the 4675 * allocation size of the buffer. 4676 */ 4677 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK; 4678 if (eoff > bp->b_offset + bp->b_bcount) 4679 eoff = bp->b_offset + bp->b_bcount; 4680 4681 /* 4682 * Set valid range. This is typically the entire buffer and thus the 4683 * entire page. 4684 */ 4685 if (eoff > off) 4686 vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off); 4687 } 4688 4689 /* 4690 * vfs_page_set_validclean: 4691 * 4692 * Set the valid bits and clear the dirty bits in a page based on the 4693 * supplied offset. The range is restricted to the buffer's size. 4694 */ 4695 static void 4696 vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4697 { 4698 vm_ooffset_t soff, eoff; 4699 4700 /* 4701 * Start and end offsets in buffer. eoff - soff may not cross a 4702 * page boundary or cross the end of the buffer. The end of the 4703 * buffer, in this case, is our file EOF, not the allocation size 4704 * of the buffer. 4705 */ 4706 soff = off; 4707 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4708 if (eoff > bp->b_offset + bp->b_bcount) 4709 eoff = bp->b_offset + bp->b_bcount; 4710 4711 /* 4712 * Set valid range. This is typically the entire buffer and thus the 4713 * entire page. 4714 */ 4715 if (eoff > soff) { 4716 vm_page_set_validclean( 4717 m, 4718 (vm_offset_t) (soff & PAGE_MASK), 4719 (vm_offset_t) (eoff - soff) 4720 ); 4721 } 4722 } 4723 4724 /* 4725 * Acquire a shared busy on all pages in the buf. 4726 */ 4727 void 4728 vfs_busy_pages_acquire(struct buf *bp) 4729 { 4730 int i; 4731 4732 for (i = 0; i < bp->b_npages; i++) 4733 vm_page_busy_acquire(bp->b_pages[i], VM_ALLOC_SBUSY); 4734 } 4735 4736 void 4737 vfs_busy_pages_release(struct buf *bp) 4738 { 4739 int i; 4740 4741 for (i = 0; i < bp->b_npages; i++) 4742 vm_page_sunbusy(bp->b_pages[i]); 4743 } 4744 4745 /* 4746 * This routine is called before a device strategy routine. 4747 * It is used to tell the VM system that paging I/O is in 4748 * progress, and treat the pages associated with the buffer 4749 * almost as being exclusive busy. Also the object paging_in_progress 4750 * flag is handled to make sure that the object doesn't become 4751 * inconsistent. 4752 * 4753 * Since I/O has not been initiated yet, certain buffer flags 4754 * such as BIO_ERROR or B_INVAL may be in an inconsistent state 4755 * and should be ignored. 4756 */ 4757 void 4758 vfs_busy_pages(struct buf *bp, int clear_modify) 4759 { 4760 vm_object_t obj; 4761 vm_ooffset_t foff; 4762 vm_page_t m; 4763 int i; 4764 bool bogus; 4765 4766 if (!(bp->b_flags & B_VMIO)) 4767 return; 4768 4769 obj = bp->b_bufobj->bo_object; 4770 foff = bp->b_offset; 4771 KASSERT(bp->b_offset != NOOFFSET, 4772 ("vfs_busy_pages: no buffer offset")); 4773 if ((bp->b_flags & B_CLUSTER) == 0) { 4774 vm_object_pip_add(obj, bp->b_npages); 4775 vfs_busy_pages_acquire(bp); 4776 } 4777 if (bp->b_bufsize != 0) 4778 vfs_setdirty_range(bp); 4779 bogus = false; 4780 for (i = 0; i < bp->b_npages; i++) { 4781 m = bp->b_pages[i]; 4782 vm_page_assert_sbusied(m); 4783 4784 /* 4785 * When readying a buffer for a read ( i.e 4786 * clear_modify == 0 ), it is important to do 4787 * bogus_page replacement for valid pages in 4788 * partially instantiated buffers. Partially 4789 * instantiated buffers can, in turn, occur when 4790 * reconstituting a buffer from its VM backing store 4791 * base. We only have to do this if B_CACHE is 4792 * clear ( which causes the I/O to occur in the 4793 * first place ). The replacement prevents the read 4794 * I/O from overwriting potentially dirty VM-backed 4795 * pages. XXX bogus page replacement is, uh, bogus. 4796 * It may not work properly with small-block devices. 4797 * We need to find a better way. 4798 */ 4799 if (clear_modify) { 4800 pmap_remove_write(m); 4801 vfs_page_set_validclean(bp, foff, m); 4802 } else if (vm_page_all_valid(m) && 4803 (bp->b_flags & B_CACHE) == 0) { 4804 bp->b_pages[i] = bogus_page; 4805 bogus = true; 4806 } 4807 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4808 } 4809 if (bogus && buf_mapped(bp)) { 4810 BUF_CHECK_MAPPED(bp); 4811 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4812 bp->b_pages, bp->b_npages); 4813 } 4814 } 4815 4816 /* 4817 * vfs_bio_set_valid: 4818 * 4819 * Set the range within the buffer to valid. The range is 4820 * relative to the beginning of the buffer, b_offset. Note that 4821 * b_offset itself may be offset from the beginning of the first 4822 * page. 4823 */ 4824 void 4825 vfs_bio_set_valid(struct buf *bp, int base, int size) 4826 { 4827 int i, n; 4828 vm_page_t m; 4829 4830 if (!(bp->b_flags & B_VMIO)) 4831 return; 4832 4833 /* 4834 * Fixup base to be relative to beginning of first page. 4835 * Set initial n to be the maximum number of bytes in the 4836 * first page that can be validated. 4837 */ 4838 base += (bp->b_offset & PAGE_MASK); 4839 n = PAGE_SIZE - (base & PAGE_MASK); 4840 4841 /* 4842 * Busy may not be strictly necessary here because the pages are 4843 * unlikely to be fully valid and the vnode lock will synchronize 4844 * their access via getpages. It is grabbed for consistency with 4845 * other page validation. 4846 */ 4847 vfs_busy_pages_acquire(bp); 4848 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4849 m = bp->b_pages[i]; 4850 if (n > size) 4851 n = size; 4852 vm_page_set_valid_range(m, base & PAGE_MASK, n); 4853 base += n; 4854 size -= n; 4855 n = PAGE_SIZE; 4856 } 4857 vfs_busy_pages_release(bp); 4858 } 4859 4860 /* 4861 * vfs_bio_clrbuf: 4862 * 4863 * If the specified buffer is a non-VMIO buffer, clear the entire 4864 * buffer. If the specified buffer is a VMIO buffer, clear and 4865 * validate only the previously invalid portions of the buffer. 4866 * This routine essentially fakes an I/O, so we need to clear 4867 * BIO_ERROR and B_INVAL. 4868 * 4869 * Note that while we only theoretically need to clear through b_bcount, 4870 * we go ahead and clear through b_bufsize. 4871 */ 4872 void 4873 vfs_bio_clrbuf(struct buf *bp) 4874 { 4875 int i, j, sa, ea, slide, zbits; 4876 vm_page_bits_t mask; 4877 4878 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) { 4879 clrbuf(bp); 4880 return; 4881 } 4882 bp->b_flags &= ~B_INVAL; 4883 bp->b_ioflags &= ~BIO_ERROR; 4884 vfs_busy_pages_acquire(bp); 4885 sa = bp->b_offset & PAGE_MASK; 4886 slide = 0; 4887 for (i = 0; i < bp->b_npages; i++, sa = 0) { 4888 slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize); 4889 ea = slide & PAGE_MASK; 4890 if (ea == 0) 4891 ea = PAGE_SIZE; 4892 if (bp->b_pages[i] == bogus_page) 4893 continue; 4894 j = sa / DEV_BSIZE; 4895 zbits = (sizeof(vm_page_bits_t) * NBBY) - 4896 (ea - sa) / DEV_BSIZE; 4897 mask = (VM_PAGE_BITS_ALL >> zbits) << j; 4898 if ((bp->b_pages[i]->valid & mask) == mask) 4899 continue; 4900 if ((bp->b_pages[i]->valid & mask) == 0) 4901 pmap_zero_page_area(bp->b_pages[i], sa, ea - sa); 4902 else { 4903 for (; sa < ea; sa += DEV_BSIZE, j++) { 4904 if ((bp->b_pages[i]->valid & (1 << j)) == 0) { 4905 pmap_zero_page_area(bp->b_pages[i], 4906 sa, DEV_BSIZE); 4907 } 4908 } 4909 } 4910 vm_page_set_valid_range(bp->b_pages[i], j * DEV_BSIZE, 4911 roundup2(ea - sa, DEV_BSIZE)); 4912 } 4913 vfs_busy_pages_release(bp); 4914 bp->b_resid = 0; 4915 } 4916 4917 void 4918 vfs_bio_bzero_buf(struct buf *bp, int base, int size) 4919 { 4920 vm_page_t m; 4921 int i, n; 4922 4923 if (buf_mapped(bp)) { 4924 BUF_CHECK_MAPPED(bp); 4925 bzero(bp->b_data + base, size); 4926 } else { 4927 BUF_CHECK_UNMAPPED(bp); 4928 n = PAGE_SIZE - (base & PAGE_MASK); 4929 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4930 m = bp->b_pages[i]; 4931 if (n > size) 4932 n = size; 4933 pmap_zero_page_area(m, base & PAGE_MASK, n); 4934 base += n; 4935 size -= n; 4936 n = PAGE_SIZE; 4937 } 4938 } 4939 } 4940 4941 /* 4942 * Update buffer flags based on I/O request parameters, optionally releasing the 4943 * buffer. If it's VMIO or direct I/O, the buffer pages are released to the VM, 4944 * where they may be placed on a page queue (VMIO) or freed immediately (direct 4945 * I/O). Otherwise the buffer is released to the cache. 4946 */ 4947 static void 4948 b_io_dismiss(struct buf *bp, int ioflag, bool release) 4949 { 4950 4951 KASSERT((ioflag & IO_NOREUSE) == 0 || (ioflag & IO_VMIO) != 0, 4952 ("buf %p non-VMIO noreuse", bp)); 4953 4954 if ((ioflag & IO_DIRECT) != 0) 4955 bp->b_flags |= B_DIRECT; 4956 if ((ioflag & IO_EXT) != 0) 4957 bp->b_xflags |= BX_ALTDATA; 4958 if ((ioflag & (IO_VMIO | IO_DIRECT)) != 0 && LIST_EMPTY(&bp->b_dep)) { 4959 bp->b_flags |= B_RELBUF; 4960 if ((ioflag & IO_NOREUSE) != 0) 4961 bp->b_flags |= B_NOREUSE; 4962 if (release) 4963 brelse(bp); 4964 } else if (release) 4965 bqrelse(bp); 4966 } 4967 4968 void 4969 vfs_bio_brelse(struct buf *bp, int ioflag) 4970 { 4971 4972 b_io_dismiss(bp, ioflag, true); 4973 } 4974 4975 void 4976 vfs_bio_set_flags(struct buf *bp, int ioflag) 4977 { 4978 4979 b_io_dismiss(bp, ioflag, false); 4980 } 4981 4982 /* 4983 * vm_hold_load_pages and vm_hold_free_pages get pages into 4984 * a buffers address space. The pages are anonymous and are 4985 * not associated with a file object. 4986 */ 4987 static void 4988 vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to) 4989 { 4990 vm_offset_t pg; 4991 vm_page_t p; 4992 int index; 4993 4994 BUF_CHECK_MAPPED(bp); 4995 4996 to = round_page(to); 4997 from = round_page(from); 4998 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 4999 MPASS((bp->b_flags & B_MAXPHYS) == 0); 5000 KASSERT(to - from <= maxbcachebuf, 5001 ("vm_hold_load_pages too large %p %#jx %#jx %u", 5002 bp, (uintmax_t)from, (uintmax_t)to, maxbcachebuf)); 5003 5004 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 5005 /* 5006 * note: must allocate system pages since blocking here 5007 * could interfere with paging I/O, no matter which 5008 * process we are. 5009 */ 5010 p = vm_page_alloc_noobj(VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | 5011 VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT) | VM_ALLOC_WAITOK); 5012 pmap_qenter(pg, &p, 1); 5013 bp->b_pages[index] = p; 5014 } 5015 bp->b_npages = index; 5016 } 5017 5018 /* Return pages associated with this buf to the vm system */ 5019 static void 5020 vm_hold_free_pages(struct buf *bp, int newbsize) 5021 { 5022 vm_offset_t from; 5023 vm_page_t p; 5024 int index, newnpages; 5025 5026 BUF_CHECK_MAPPED(bp); 5027 5028 from = round_page((vm_offset_t)bp->b_data + newbsize); 5029 newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 5030 if (bp->b_npages > newnpages) 5031 pmap_qremove(from, bp->b_npages - newnpages); 5032 for (index = newnpages; index < bp->b_npages; index++) { 5033 p = bp->b_pages[index]; 5034 bp->b_pages[index] = NULL; 5035 vm_page_unwire_noq(p); 5036 vm_page_free(p); 5037 } 5038 bp->b_npages = newnpages; 5039 } 5040 5041 /* 5042 * Map an IO request into kernel virtual address space. 5043 * 5044 * All requests are (re)mapped into kernel VA space. 5045 * Notice that we use b_bufsize for the size of the buffer 5046 * to be mapped. b_bcount might be modified by the driver. 5047 * 5048 * Note that even if the caller determines that the address space should 5049 * be valid, a race or a smaller-file mapped into a larger space may 5050 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST 5051 * check the return value. 5052 * 5053 * This function only works with pager buffers. 5054 */ 5055 int 5056 vmapbuf(struct buf *bp, void *uaddr, size_t len, int mapbuf) 5057 { 5058 vm_prot_t prot; 5059 int pidx; 5060 5061 MPASS((bp->b_flags & B_MAXPHYS) != 0); 5062 prot = VM_PROT_READ; 5063 if (bp->b_iocmd == BIO_READ) 5064 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 5065 pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 5066 (vm_offset_t)uaddr, len, prot, bp->b_pages, PBUF_PAGES); 5067 if (pidx < 0) 5068 return (-1); 5069 bp->b_bufsize = len; 5070 bp->b_npages = pidx; 5071 bp->b_offset = ((vm_offset_t)uaddr) & PAGE_MASK; 5072 if (mapbuf || !unmapped_buf_allowed) { 5073 pmap_qenter((vm_offset_t)bp->b_kvabase, bp->b_pages, pidx); 5074 bp->b_data = bp->b_kvabase + bp->b_offset; 5075 } else 5076 bp->b_data = unmapped_buf; 5077 return (0); 5078 } 5079 5080 /* 5081 * Free the io map PTEs associated with this IO operation. 5082 * We also invalidate the TLB entries and restore the original b_addr. 5083 * 5084 * This function only works with pager buffers. 5085 */ 5086 void 5087 vunmapbuf(struct buf *bp) 5088 { 5089 int npages; 5090 5091 npages = bp->b_npages; 5092 if (buf_mapped(bp)) 5093 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages); 5094 vm_page_unhold_pages(bp->b_pages, npages); 5095 5096 bp->b_data = unmapped_buf; 5097 } 5098 5099 void 5100 bdone(struct buf *bp) 5101 { 5102 struct mtx *mtxp; 5103 5104 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5105 mtx_lock(mtxp); 5106 bp->b_flags |= B_DONE; 5107 wakeup(bp); 5108 mtx_unlock(mtxp); 5109 } 5110 5111 void 5112 bwait(struct buf *bp, u_char pri, const char *wchan) 5113 { 5114 struct mtx *mtxp; 5115 5116 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5117 mtx_lock(mtxp); 5118 while ((bp->b_flags & B_DONE) == 0) 5119 msleep(bp, mtxp, pri, wchan, 0); 5120 mtx_unlock(mtxp); 5121 } 5122 5123 int 5124 bufsync(struct bufobj *bo, int waitfor) 5125 { 5126 5127 return (VOP_FSYNC(bo2vnode(bo), waitfor, curthread)); 5128 } 5129 5130 void 5131 bufstrategy(struct bufobj *bo, struct buf *bp) 5132 { 5133 int i __unused; 5134 struct vnode *vp; 5135 5136 vp = bp->b_vp; 5137 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy")); 5138 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 5139 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp)); 5140 i = VOP_STRATEGY(vp, bp); 5141 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp)); 5142 } 5143 5144 /* 5145 * Initialize a struct bufobj before use. Memory is assumed zero filled. 5146 */ 5147 void 5148 bufobj_init(struct bufobj *bo, void *private) 5149 { 5150 static volatile int bufobj_cleanq; 5151 5152 bo->bo_domain = 5153 atomic_fetchadd_int(&bufobj_cleanq, 1) % buf_domains; 5154 rw_init(BO_LOCKPTR(bo), "bufobj interlock"); 5155 bo->bo_private = private; 5156 TAILQ_INIT(&bo->bo_clean.bv_hd); 5157 pctrie_init(&bo->bo_clean.bv_root); 5158 TAILQ_INIT(&bo->bo_dirty.bv_hd); 5159 pctrie_init(&bo->bo_dirty.bv_root); 5160 } 5161 5162 void 5163 bufobj_wrefl(struct bufobj *bo) 5164 { 5165 5166 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5167 ASSERT_BO_WLOCKED(bo); 5168 bo->bo_numoutput++; 5169 } 5170 5171 void 5172 bufobj_wref(struct bufobj *bo) 5173 { 5174 5175 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5176 BO_LOCK(bo); 5177 bo->bo_numoutput++; 5178 BO_UNLOCK(bo); 5179 } 5180 5181 void 5182 bufobj_wdrop(struct bufobj *bo) 5183 { 5184 5185 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop")); 5186 BO_LOCK(bo); 5187 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count")); 5188 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) { 5189 bo->bo_flag &= ~BO_WWAIT; 5190 wakeup(&bo->bo_numoutput); 5191 } 5192 BO_UNLOCK(bo); 5193 } 5194 5195 int 5196 bufobj_wwait(struct bufobj *bo, int slpflag, int timeo) 5197 { 5198 int error; 5199 5200 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait")); 5201 ASSERT_BO_WLOCKED(bo); 5202 error = 0; 5203 while (bo->bo_numoutput) { 5204 bo->bo_flag |= BO_WWAIT; 5205 error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo), 5206 slpflag | (PRIBIO + 1), "bo_wwait", timeo); 5207 if (error) 5208 break; 5209 } 5210 return (error); 5211 } 5212 5213 /* 5214 * Set bio_data or bio_ma for struct bio from the struct buf. 5215 */ 5216 void 5217 bdata2bio(struct buf *bp, struct bio *bip) 5218 { 5219 5220 if (!buf_mapped(bp)) { 5221 KASSERT(unmapped_buf_allowed, ("unmapped")); 5222 bip->bio_ma = bp->b_pages; 5223 bip->bio_ma_n = bp->b_npages; 5224 bip->bio_data = unmapped_buf; 5225 bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK; 5226 bip->bio_flags |= BIO_UNMAPPED; 5227 KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) / 5228 PAGE_SIZE == bp->b_npages, 5229 ("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset, 5230 (long long)bip->bio_length, bip->bio_ma_n)); 5231 } else { 5232 bip->bio_data = bp->b_data; 5233 bip->bio_ma = NULL; 5234 } 5235 } 5236 5237 struct memdesc 5238 memdesc_bio(struct bio *bio) 5239 { 5240 if ((bio->bio_flags & BIO_VLIST) != 0) 5241 return (memdesc_vlist((struct bus_dma_segment *)bio->bio_data, 5242 bio->bio_ma_n)); 5243 5244 if ((bio->bio_flags & BIO_UNMAPPED) != 0) 5245 return (memdesc_vmpages(bio->bio_ma, bio->bio_bcount, 5246 bio->bio_ma_offset)); 5247 5248 return (memdesc_vaddr(bio->bio_data, bio->bio_bcount)); 5249 } 5250 5251 static int buf_pager_relbuf; 5252 SYSCTL_INT(_vfs, OID_AUTO, buf_pager_relbuf, CTLFLAG_RWTUN, 5253 &buf_pager_relbuf, 0, 5254 "Make buffer pager release buffers after reading"); 5255 5256 /* 5257 * The buffer pager. It uses buffer reads to validate pages. 5258 * 5259 * In contrast to the generic local pager from vm/vnode_pager.c, this 5260 * pager correctly and easily handles volumes where the underlying 5261 * device block size is greater than the machine page size. The 5262 * buffer cache transparently extends the requested page run to be 5263 * aligned at the block boundary, and does the necessary bogus page 5264 * replacements in the addends to avoid obliterating already valid 5265 * pages. 5266 * 5267 * The only non-trivial issue is that the exclusive busy state for 5268 * pages, which is assumed by the vm_pager_getpages() interface, is 5269 * incompatible with the VMIO buffer cache's desire to share-busy the 5270 * pages. This function performs a trivial downgrade of the pages' 5271 * state before reading buffers, and a less trivial upgrade from the 5272 * shared-busy to excl-busy state after the read. 5273 */ 5274 int 5275 vfs_bio_getpages(struct vnode *vp, vm_page_t *ma, int count, 5276 int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno, 5277 vbg_get_blksize_t get_blksize) 5278 { 5279 vm_page_t m; 5280 vm_object_t object; 5281 struct buf *bp; 5282 struct mount *mp; 5283 daddr_t lbn, lbnp; 5284 vm_ooffset_t la, lb, poff, poffe; 5285 long bo_bs, bsize; 5286 int br_flags, error, i, pgsin, pgsin_a, pgsin_b; 5287 bool redo, lpart; 5288 5289 object = vp->v_object; 5290 mp = vp->v_mount; 5291 error = 0; 5292 la = IDX_TO_OFF(ma[count - 1]->pindex); 5293 if (la >= object->un_pager.vnp.vnp_size) 5294 return (VM_PAGER_BAD); 5295 5296 /* 5297 * Change the meaning of la from where the last requested page starts 5298 * to where it ends, because that's the end of the requested region 5299 * and the start of the potential read-ahead region. 5300 */ 5301 la += PAGE_SIZE; 5302 lpart = la > object->un_pager.vnp.vnp_size; 5303 error = get_blksize(vp, get_lblkno(vp, IDX_TO_OFF(ma[0]->pindex)), 5304 &bo_bs); 5305 if (error != 0) 5306 return (VM_PAGER_ERROR); 5307 5308 /* 5309 * Calculate read-ahead, behind and total pages. 5310 */ 5311 pgsin = count; 5312 lb = IDX_TO_OFF(ma[0]->pindex); 5313 pgsin_b = OFF_TO_IDX(lb - rounddown2(lb, bo_bs)); 5314 pgsin += pgsin_b; 5315 if (rbehind != NULL) 5316 *rbehind = pgsin_b; 5317 pgsin_a = OFF_TO_IDX(roundup2(la, bo_bs) - la); 5318 if (la + IDX_TO_OFF(pgsin_a) >= object->un_pager.vnp.vnp_size) 5319 pgsin_a = OFF_TO_IDX(roundup2(object->un_pager.vnp.vnp_size, 5320 PAGE_SIZE) - la); 5321 pgsin += pgsin_a; 5322 if (rahead != NULL) 5323 *rahead = pgsin_a; 5324 VM_CNT_INC(v_vnodein); 5325 VM_CNT_ADD(v_vnodepgsin, pgsin); 5326 5327 br_flags = (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) 5328 != 0) ? GB_UNMAPPED : 0; 5329 again: 5330 for (i = 0; i < count; i++) { 5331 if (ma[i] != bogus_page) 5332 vm_page_busy_downgrade(ma[i]); 5333 } 5334 5335 lbnp = -1; 5336 for (i = 0; i < count; i++) { 5337 m = ma[i]; 5338 if (m == bogus_page) 5339 continue; 5340 5341 /* 5342 * Pages are shared busy and the object lock is not 5343 * owned, which together allow for the pages' 5344 * invalidation. The racy test for validity avoids 5345 * useless creation of the buffer for the most typical 5346 * case when invalidation is not used in redo or for 5347 * parallel read. The shared->excl upgrade loop at 5348 * the end of the function catches the race in a 5349 * reliable way (protected by the object lock). 5350 */ 5351 if (vm_page_all_valid(m)) 5352 continue; 5353 5354 poff = IDX_TO_OFF(m->pindex); 5355 poffe = MIN(poff + PAGE_SIZE, object->un_pager.vnp.vnp_size); 5356 for (; poff < poffe; poff += bsize) { 5357 lbn = get_lblkno(vp, poff); 5358 if (lbn == lbnp) 5359 goto next_page; 5360 lbnp = lbn; 5361 5362 error = get_blksize(vp, lbn, &bsize); 5363 if (error == 0) 5364 error = bread_gb(vp, lbn, bsize, 5365 curthread->td_ucred, br_flags, &bp); 5366 if (error != 0) 5367 goto end_pages; 5368 if (bp->b_rcred == curthread->td_ucred) { 5369 crfree(bp->b_rcred); 5370 bp->b_rcred = NOCRED; 5371 } 5372 if (LIST_EMPTY(&bp->b_dep)) { 5373 /* 5374 * Invalidation clears m->valid, but 5375 * may leave B_CACHE flag if the 5376 * buffer existed at the invalidation 5377 * time. In this case, recycle the 5378 * buffer to do real read on next 5379 * bread() after redo. 5380 * 5381 * Otherwise B_RELBUF is not strictly 5382 * necessary, enable to reduce buf 5383 * cache pressure. 5384 */ 5385 if (buf_pager_relbuf || 5386 !vm_page_all_valid(m)) 5387 bp->b_flags |= B_RELBUF; 5388 5389 bp->b_flags &= ~B_NOCACHE; 5390 brelse(bp); 5391 } else { 5392 bqrelse(bp); 5393 } 5394 } 5395 KASSERT(1 /* racy, enable for debugging */ || 5396 vm_page_all_valid(m) || i == count - 1, 5397 ("buf %d %p invalid", i, m)); 5398 if (i == count - 1 && lpart) { 5399 if (!vm_page_none_valid(m) && 5400 !vm_page_all_valid(m)) 5401 vm_page_zero_invalid(m, TRUE); 5402 } 5403 next_page:; 5404 } 5405 end_pages: 5406 5407 redo = false; 5408 for (i = 0; i < count; i++) { 5409 if (ma[i] == bogus_page) 5410 continue; 5411 if (vm_page_busy_tryupgrade(ma[i]) == 0) { 5412 vm_page_sunbusy(ma[i]); 5413 ma[i] = vm_page_grab_unlocked(object, ma[i]->pindex, 5414 VM_ALLOC_NORMAL); 5415 } 5416 5417 /* 5418 * Since the pages were only sbusy while neither the 5419 * buffer nor the object lock was held by us, or 5420 * reallocated while vm_page_grab() slept for busy 5421 * relinguish, they could have been invalidated. 5422 * Recheck the valid bits and re-read as needed. 5423 * 5424 * Note that the last page is made fully valid in the 5425 * read loop, and partial validity for the page at 5426 * index count - 1 could mean that the page was 5427 * invalidated or removed, so we must restart for 5428 * safety as well. 5429 */ 5430 if (!vm_page_all_valid(ma[i])) 5431 redo = true; 5432 } 5433 if (redo && error == 0) 5434 goto again; 5435 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 5436 } 5437 5438 #include "opt_ddb.h" 5439 #ifdef DDB 5440 #include <ddb/ddb.h> 5441 5442 /* DDB command to show buffer data */ 5443 DB_SHOW_COMMAND(buffer, db_show_buffer) 5444 { 5445 /* get args */ 5446 struct buf *bp = (struct buf *)addr; 5447 #ifdef FULL_BUF_TRACKING 5448 uint32_t i, j; 5449 #endif 5450 5451 if (!have_addr) { 5452 db_printf("usage: show buffer <addr>\n"); 5453 return; 5454 } 5455 5456 db_printf("buf at %p\n", bp); 5457 db_printf("b_flags = 0x%b, b_xflags=0x%b\n", 5458 (u_int)bp->b_flags, PRINT_BUF_FLAGS, 5459 (u_int)bp->b_xflags, PRINT_BUF_XFLAGS); 5460 db_printf("b_vflags=0x%b b_ioflags0x%b\n", 5461 (u_int)bp->b_vflags, PRINT_BUF_VFLAGS, 5462 (u_int)bp->b_ioflags, PRINT_BIO_FLAGS); 5463 db_printf( 5464 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n" 5465 "b_bufobj = (%p), b_data = %p\n, b_blkno = %jd, b_lblkno = %jd, " 5466 "b_vp = %p, b_dep = %p\n", 5467 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 5468 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno, 5469 (intmax_t)bp->b_lblkno, bp->b_vp, bp->b_dep.lh_first); 5470 db_printf("b_kvabase = %p, b_kvasize = %d\n", 5471 bp->b_kvabase, bp->b_kvasize); 5472 if (bp->b_npages) { 5473 int i; 5474 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 5475 for (i = 0; i < bp->b_npages; i++) { 5476 vm_page_t m; 5477 m = bp->b_pages[i]; 5478 if (m != NULL) 5479 db_printf("(%p, 0x%lx, 0x%lx)", m->object, 5480 (u_long)m->pindex, 5481 (u_long)VM_PAGE_TO_PHYS(m)); 5482 else 5483 db_printf("( ??? )"); 5484 if ((i + 1) < bp->b_npages) 5485 db_printf(","); 5486 } 5487 db_printf("\n"); 5488 } 5489 BUF_LOCKPRINTINFO(bp); 5490 #if defined(FULL_BUF_TRACKING) 5491 db_printf("b_io_tracking: b_io_tcnt = %u\n", bp->b_io_tcnt); 5492 5493 i = bp->b_io_tcnt % BUF_TRACKING_SIZE; 5494 for (j = 1; j <= BUF_TRACKING_SIZE; j++) { 5495 if (bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)] == NULL) 5496 continue; 5497 db_printf(" %2u: %s\n", j, 5498 bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)]); 5499 } 5500 #elif defined(BUF_TRACKING) 5501 db_printf("b_io_tracking: %s\n", bp->b_io_tracking); 5502 #endif 5503 db_printf(" "); 5504 } 5505 5506 DB_SHOW_COMMAND_FLAGS(bufqueues, bufqueues, DB_CMD_MEMSAFE) 5507 { 5508 struct bufdomain *bd; 5509 struct buf *bp; 5510 long total; 5511 int i, j, cnt; 5512 5513 db_printf("bqempty: %d\n", bqempty.bq_len); 5514 5515 for (i = 0; i < buf_domains; i++) { 5516 bd = &bdomain[i]; 5517 db_printf("Buf domain %d\n", i); 5518 db_printf("\tfreebufs\t%d\n", bd->bd_freebuffers); 5519 db_printf("\tlofreebufs\t%d\n", bd->bd_lofreebuffers); 5520 db_printf("\thifreebufs\t%d\n", bd->bd_hifreebuffers); 5521 db_printf("\n"); 5522 db_printf("\tbufspace\t%ld\n", bd->bd_bufspace); 5523 db_printf("\tmaxbufspace\t%ld\n", bd->bd_maxbufspace); 5524 db_printf("\thibufspace\t%ld\n", bd->bd_hibufspace); 5525 db_printf("\tlobufspace\t%ld\n", bd->bd_lobufspace); 5526 db_printf("\tbufspacethresh\t%ld\n", bd->bd_bufspacethresh); 5527 db_printf("\n"); 5528 db_printf("\tnumdirtybuffers\t%d\n", bd->bd_numdirtybuffers); 5529 db_printf("\tlodirtybuffers\t%d\n", bd->bd_lodirtybuffers); 5530 db_printf("\thidirtybuffers\t%d\n", bd->bd_hidirtybuffers); 5531 db_printf("\tdirtybufthresh\t%d\n", bd->bd_dirtybufthresh); 5532 db_printf("\n"); 5533 total = 0; 5534 TAILQ_FOREACH(bp, &bd->bd_cleanq->bq_queue, b_freelist) 5535 total += bp->b_bufsize; 5536 db_printf("\tcleanq count\t%d (%ld)\n", 5537 bd->bd_cleanq->bq_len, total); 5538 total = 0; 5539 TAILQ_FOREACH(bp, &bd->bd_dirtyq.bq_queue, b_freelist) 5540 total += bp->b_bufsize; 5541 db_printf("\tdirtyq count\t%d (%ld)\n", 5542 bd->bd_dirtyq.bq_len, total); 5543 db_printf("\twakeup\t\t%d\n", bd->bd_wanted); 5544 db_printf("\tlim\t\t%d\n", bd->bd_lim); 5545 db_printf("\tCPU "); 5546 for (j = 0; j <= mp_maxid; j++) 5547 db_printf("%d, ", bd->bd_subq[j].bq_len); 5548 db_printf("\n"); 5549 cnt = 0; 5550 total = 0; 5551 for (j = 0; j < nbuf; j++) { 5552 bp = nbufp(j); 5553 if (bp->b_domain == i && BUF_ISLOCKED(bp)) { 5554 cnt++; 5555 total += bp->b_bufsize; 5556 } 5557 } 5558 db_printf("\tLocked buffers: %d space %ld\n", cnt, total); 5559 cnt = 0; 5560 total = 0; 5561 for (j = 0; j < nbuf; j++) { 5562 bp = nbufp(j); 5563 if (bp->b_domain == i) { 5564 cnt++; 5565 total += bp->b_bufsize; 5566 } 5567 } 5568 db_printf("\tTotal buffers: %d space %ld\n", cnt, total); 5569 } 5570 } 5571 5572 DB_SHOW_COMMAND_FLAGS(lockedbufs, lockedbufs, DB_CMD_MEMSAFE) 5573 { 5574 struct buf *bp; 5575 int i; 5576 5577 for (i = 0; i < nbuf; i++) { 5578 bp = nbufp(i); 5579 if (BUF_ISLOCKED(bp)) { 5580 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5581 db_printf("\n"); 5582 if (db_pager_quit) 5583 break; 5584 } 5585 } 5586 } 5587 5588 DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs) 5589 { 5590 struct vnode *vp; 5591 struct buf *bp; 5592 5593 if (!have_addr) { 5594 db_printf("usage: show vnodebufs <addr>\n"); 5595 return; 5596 } 5597 vp = (struct vnode *)addr; 5598 db_printf("Clean buffers:\n"); 5599 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) { 5600 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5601 db_printf("\n"); 5602 } 5603 db_printf("Dirty buffers:\n"); 5604 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) { 5605 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5606 db_printf("\n"); 5607 } 5608 } 5609 5610 DB_COMMAND_FLAGS(countfreebufs, db_coundfreebufs, DB_CMD_MEMSAFE) 5611 { 5612 struct buf *bp; 5613 int i, used = 0, nfree = 0; 5614 5615 if (have_addr) { 5616 db_printf("usage: countfreebufs\n"); 5617 return; 5618 } 5619 5620 for (i = 0; i < nbuf; i++) { 5621 bp = nbufp(i); 5622 if (bp->b_qindex == QUEUE_EMPTY) 5623 nfree++; 5624 else 5625 used++; 5626 } 5627 5628 db_printf("Counted %d free, %d used (%d tot)\n", nfree, used, 5629 nfree + used); 5630 db_printf("numfreebuffers is %d\n", numfreebuffers); 5631 } 5632 #endif /* DDB */ 5633