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/param.h> 48 #include <sys/systm.h> 49 #include <sys/asan.h> 50 #include <sys/bio.h> 51 #include <sys/bitset.h> 52 #include <sys/boottrace.h> 53 #include <sys/buf.h> 54 #include <sys/conf.h> 55 #include <sys/counter.h> 56 #include <sys/devicestat.h> 57 #include <sys/eventhandler.h> 58 #include <sys/fail.h> 59 #include <sys/ktr.h> 60 #include <sys/limits.h> 61 #include <sys/lock.h> 62 #include <sys/malloc.h> 63 #include <sys/memdesc.h> 64 #include <sys/mount.h> 65 #include <sys/mutex.h> 66 #include <sys/kernel.h> 67 #include <sys/kthread.h> 68 #include <sys/pctrie.h> 69 #include <sys/proc.h> 70 #include <sys/racct.h> 71 #include <sys/refcount.h> 72 #include <sys/resourcevar.h> 73 #include <sys/rwlock.h> 74 #include <sys/sched.h> 75 #include <sys/smp.h> 76 #include <sys/sysctl.h> 77 #include <sys/syscallsubr.h> 78 #include <sys/vmem.h> 79 #include <sys/vmmeter.h> 80 #include <sys/vnode.h> 81 #include <sys/watchdog.h> 82 #include <geom/geom.h> 83 #include <vm/vm.h> 84 #include <vm/vm_param.h> 85 #include <vm/vm_kern.h> 86 #include <vm/vm_object.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_pageout.h> 89 #include <vm/vm_pager.h> 90 #include <vm/vm_extern.h> 91 #include <vm/vm_map.h> 92 #include <vm/swap_pager.h> 93 94 static MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer"); 95 96 struct bio_ops bioops; /* I/O operation notification */ 97 98 struct buf_ops buf_ops_bio = { 99 .bop_name = "buf_ops_bio", 100 .bop_write = bufwrite, 101 .bop_strategy = bufstrategy, 102 .bop_sync = bufsync, 103 .bop_bdflush = bufbdflush, 104 }; 105 106 struct bufqueue { 107 struct mtx_padalign bq_lock; 108 TAILQ_HEAD(, buf) bq_queue; 109 uint8_t bq_index; 110 uint16_t bq_subqueue; 111 int bq_len; 112 } __aligned(CACHE_LINE_SIZE); 113 114 #define BQ_LOCKPTR(bq) (&(bq)->bq_lock) 115 #define BQ_LOCK(bq) mtx_lock(BQ_LOCKPTR((bq))) 116 #define BQ_UNLOCK(bq) mtx_unlock(BQ_LOCKPTR((bq))) 117 #define BQ_ASSERT_LOCKED(bq) mtx_assert(BQ_LOCKPTR((bq)), MA_OWNED) 118 119 struct bufdomain { 120 struct bufqueue *bd_subq; 121 struct bufqueue bd_dirtyq; 122 struct bufqueue *bd_cleanq; 123 struct mtx_padalign bd_run_lock; 124 /* Constants */ 125 long bd_maxbufspace; 126 long bd_hibufspace; 127 long bd_lobufspace; 128 long bd_bufspacethresh; 129 int bd_hifreebuffers; 130 int bd_lofreebuffers; 131 int bd_hidirtybuffers; 132 int bd_lodirtybuffers; 133 int bd_dirtybufthresh; 134 int bd_lim; 135 /* atomics */ 136 int bd_wanted; 137 bool bd_shutdown; 138 int __aligned(CACHE_LINE_SIZE) bd_numdirtybuffers; 139 int __aligned(CACHE_LINE_SIZE) bd_running; 140 long __aligned(CACHE_LINE_SIZE) bd_bufspace; 141 int __aligned(CACHE_LINE_SIZE) bd_freebuffers; 142 } __aligned(CACHE_LINE_SIZE); 143 144 #define BD_LOCKPTR(bd) (&(bd)->bd_cleanq->bq_lock) 145 #define BD_LOCK(bd) mtx_lock(BD_LOCKPTR((bd))) 146 #define BD_UNLOCK(bd) mtx_unlock(BD_LOCKPTR((bd))) 147 #define BD_ASSERT_LOCKED(bd) mtx_assert(BD_LOCKPTR((bd)), MA_OWNED) 148 #define BD_RUN_LOCKPTR(bd) (&(bd)->bd_run_lock) 149 #define BD_RUN_LOCK(bd) mtx_lock(BD_RUN_LOCKPTR((bd))) 150 #define BD_RUN_UNLOCK(bd) mtx_unlock(BD_RUN_LOCKPTR((bd))) 151 #define BD_DOMAIN(bd) (bd - bdomain) 152 153 static char *buf; /* buffer header pool */ 154 static struct buf * 155 nbufp(unsigned i) 156 { 157 return ((struct buf *)(buf + (sizeof(struct buf) + 158 sizeof(vm_page_t) * atop(maxbcachebuf)) * i)); 159 } 160 161 caddr_t __read_mostly unmapped_buf; 162 #ifdef INVARIANTS 163 caddr_t poisoned_buf = (void *)-1; 164 #endif 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, 326 CTLFLAG_RDTUN | CTLFLAG_NOFETCH, 327 &unmapped_buf_allowed, 0, 328 "Permit the use of the unmapped i/o"); 329 int maxbcachebuf = MAXBCACHEBUF; 330 SYSCTL_INT(_vfs, OID_AUTO, maxbcachebuf, CTLFLAG_RDTUN, &maxbcachebuf, 0, 331 "Maximum size of a buffer cache block"); 332 333 /* 334 * This lock synchronizes access to bd_request. 335 */ 336 static struct mtx_padalign __exclusive_cache_line bdlock; 337 338 /* 339 * This lock protects the runningbufreq and synchronizes runningbufwakeup and 340 * waitrunningbufspace(). 341 */ 342 static struct mtx_padalign __exclusive_cache_line rbreqlock; 343 344 /* 345 * Lock that protects bdirtywait. 346 */ 347 static struct mtx_padalign __exclusive_cache_line bdirtylock; 348 349 /* 350 * bufdaemon shutdown request and sleep channel. 351 */ 352 static bool bd_shutdown; 353 354 /* 355 * Wakeup point for bufdaemon, as well as indicator of whether it is already 356 * active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it 357 * is idling. 358 */ 359 static int bd_request; 360 361 /* 362 * Request for the buf daemon to write more buffers than is indicated by 363 * lodirtybuf. This may be necessary to push out excess dependencies or 364 * defragment the address space where a simple count of the number of dirty 365 * buffers is insufficient to characterize the demand for flushing them. 366 */ 367 static int bd_speedupreq; 368 369 /* 370 * Synchronization (sleep/wakeup) variable for active buffer space requests. 371 * Set when wait starts, cleared prior to wakeup(). 372 * Used in runningbufwakeup() and waitrunningbufspace(). 373 */ 374 static int runningbufreq; 375 376 /* 377 * Synchronization for bwillwrite() waiters. 378 */ 379 static int bdirtywait; 380 381 /* 382 * Definitions for the buffer free lists. 383 */ 384 #define QUEUE_NONE 0 /* on no queue */ 385 #define QUEUE_EMPTY 1 /* empty buffer headers */ 386 #define QUEUE_DIRTY 2 /* B_DELWRI buffers */ 387 #define QUEUE_CLEAN 3 /* non-B_DELWRI buffers */ 388 #define QUEUE_SENTINEL 4 /* not an queue index, but mark for sentinel */ 389 390 /* Maximum number of buffer domains. */ 391 #define BUF_DOMAINS 8 392 393 struct bufdomainset bdlodirty; /* Domains > lodirty */ 394 struct bufdomainset bdhidirty; /* Domains > hidirty */ 395 396 /* Configured number of clean queues. */ 397 static int __read_mostly buf_domains; 398 399 BITSET_DEFINE(bufdomainset, BUF_DOMAINS); 400 struct bufdomain __exclusive_cache_line bdomain[BUF_DOMAINS]; 401 struct bufqueue __exclusive_cache_line bqempty; 402 403 /* 404 * per-cpu empty buffer cache. 405 */ 406 uma_zone_t buf_zone; 407 408 static int 409 sysctl_runningspace(SYSCTL_HANDLER_ARGS) 410 { 411 long value; 412 int error; 413 414 value = *(long *)arg1; 415 error = sysctl_handle_long(oidp, &value, 0, req); 416 if (error != 0 || req->newptr == NULL) 417 return (error); 418 mtx_lock(&rbreqlock); 419 if (arg1 == &hirunningspace) { 420 if (value < lorunningspace) 421 error = EINVAL; 422 else 423 hirunningspace = value; 424 } else { 425 KASSERT(arg1 == &lorunningspace, 426 ("%s: unknown arg1", __func__)); 427 if (value > hirunningspace) 428 error = EINVAL; 429 else 430 lorunningspace = value; 431 } 432 mtx_unlock(&rbreqlock); 433 return (error); 434 } 435 436 static int 437 sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS) 438 { 439 int error; 440 int value; 441 int i; 442 443 value = *(int *)arg1; 444 error = sysctl_handle_int(oidp, &value, 0, req); 445 if (error != 0 || req->newptr == NULL) 446 return (error); 447 *(int *)arg1 = value; 448 for (i = 0; i < buf_domains; i++) 449 *(int *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 450 value / buf_domains; 451 452 return (error); 453 } 454 455 static int 456 sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS) 457 { 458 long value; 459 int error; 460 int i; 461 462 value = *(long *)arg1; 463 error = sysctl_handle_long(oidp, &value, 0, req); 464 if (error != 0 || req->newptr == NULL) 465 return (error); 466 *(long *)arg1 = value; 467 for (i = 0; i < buf_domains; i++) 468 *(long *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 469 value / buf_domains; 470 471 return (error); 472 } 473 474 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 475 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 476 static int 477 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 478 { 479 long lvalue; 480 int ivalue; 481 int i; 482 483 lvalue = 0; 484 for (i = 0; i < buf_domains; i++) 485 lvalue += bdomain[i].bd_bufspace; 486 if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long)) 487 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 488 if (lvalue > INT_MAX) 489 /* On overflow, still write out a long to trigger ENOMEM. */ 490 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 491 ivalue = lvalue; 492 return (sysctl_handle_int(oidp, &ivalue, 0, req)); 493 } 494 #else 495 static int 496 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 497 { 498 long lvalue; 499 int i; 500 501 lvalue = 0; 502 for (i = 0; i < buf_domains; i++) 503 lvalue += bdomain[i].bd_bufspace; 504 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 505 } 506 #endif 507 508 static int 509 sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS) 510 { 511 int value; 512 int i; 513 514 value = 0; 515 for (i = 0; i < buf_domains; i++) 516 value += bdomain[i].bd_numdirtybuffers; 517 return (sysctl_handle_int(oidp, &value, 0, req)); 518 } 519 520 /* 521 * bdirtywakeup: 522 * 523 * Wakeup any bwillwrite() waiters. 524 */ 525 static void 526 bdirtywakeup(void) 527 { 528 mtx_lock(&bdirtylock); 529 if (bdirtywait) { 530 bdirtywait = 0; 531 wakeup(&bdirtywait); 532 } 533 mtx_unlock(&bdirtylock); 534 } 535 536 /* 537 * bd_clear: 538 * 539 * Clear a domain from the appropriate bitsets when dirtybuffers 540 * is decremented. 541 */ 542 static void 543 bd_clear(struct bufdomain *bd) 544 { 545 546 mtx_lock(&bdirtylock); 547 if (bd->bd_numdirtybuffers <= bd->bd_lodirtybuffers) 548 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 549 if (bd->bd_numdirtybuffers <= bd->bd_hidirtybuffers) 550 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 551 mtx_unlock(&bdirtylock); 552 } 553 554 /* 555 * bd_set: 556 * 557 * Set a domain in the appropriate bitsets when dirtybuffers 558 * is incremented. 559 */ 560 static void 561 bd_set(struct bufdomain *bd) 562 { 563 564 mtx_lock(&bdirtylock); 565 if (bd->bd_numdirtybuffers > bd->bd_lodirtybuffers) 566 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 567 if (bd->bd_numdirtybuffers > bd->bd_hidirtybuffers) 568 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 569 mtx_unlock(&bdirtylock); 570 } 571 572 /* 573 * bdirtysub: 574 * 575 * Decrement the numdirtybuffers count by one and wakeup any 576 * threads blocked in bwillwrite(). 577 */ 578 static void 579 bdirtysub(struct buf *bp) 580 { 581 struct bufdomain *bd; 582 int num; 583 584 bd = bufdomain(bp); 585 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, -1); 586 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 587 bdirtywakeup(); 588 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 589 bd_clear(bd); 590 } 591 592 /* 593 * bdirtyadd: 594 * 595 * Increment the numdirtybuffers count by one and wakeup the buf 596 * daemon if needed. 597 */ 598 static void 599 bdirtyadd(struct buf *bp) 600 { 601 struct bufdomain *bd; 602 int num; 603 604 /* 605 * Only do the wakeup once as we cross the boundary. The 606 * buf daemon will keep running until the condition clears. 607 */ 608 bd = bufdomain(bp); 609 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, 1); 610 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 611 bd_wakeup(); 612 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 613 bd_set(bd); 614 } 615 616 /* 617 * bufspace_daemon_wakeup: 618 * 619 * Wakeup the daemons responsible for freeing clean bufs. 620 */ 621 static void 622 bufspace_daemon_wakeup(struct bufdomain *bd) 623 { 624 625 /* 626 * avoid the lock if the daemon is running. 627 */ 628 if (atomic_fetchadd_int(&bd->bd_running, 1) == 0) { 629 BD_RUN_LOCK(bd); 630 atomic_store_int(&bd->bd_running, 1); 631 wakeup(&bd->bd_running); 632 BD_RUN_UNLOCK(bd); 633 } 634 } 635 636 /* 637 * bufspace_adjust: 638 * 639 * Adjust the reported bufspace for a KVA managed buffer, possibly 640 * waking any waiters. 641 */ 642 static void 643 bufspace_adjust(struct buf *bp, int bufsize) 644 { 645 struct bufdomain *bd; 646 long space; 647 int diff; 648 649 KASSERT((bp->b_flags & B_MALLOC) == 0, 650 ("bufspace_adjust: malloc buf %p", bp)); 651 bd = bufdomain(bp); 652 diff = bufsize - bp->b_bufsize; 653 if (diff < 0) { 654 atomic_subtract_long(&bd->bd_bufspace, -diff); 655 } else if (diff > 0) { 656 space = atomic_fetchadd_long(&bd->bd_bufspace, diff); 657 /* Wake up the daemon on the transition. */ 658 if (space < bd->bd_bufspacethresh && 659 space + diff >= bd->bd_bufspacethresh) 660 bufspace_daemon_wakeup(bd); 661 } 662 bp->b_bufsize = bufsize; 663 } 664 665 /* 666 * bufspace_reserve: 667 * 668 * Reserve bufspace before calling allocbuf(). metadata has a 669 * different space limit than data. 670 */ 671 static int 672 bufspace_reserve(struct bufdomain *bd, int size, bool metadata) 673 { 674 long limit, new; 675 long space; 676 677 if (metadata) 678 limit = bd->bd_maxbufspace; 679 else 680 limit = bd->bd_hibufspace; 681 space = atomic_fetchadd_long(&bd->bd_bufspace, size); 682 new = space + size; 683 if (new > limit) { 684 atomic_subtract_long(&bd->bd_bufspace, size); 685 return (ENOSPC); 686 } 687 688 /* Wake up the daemon on the transition. */ 689 if (space < bd->bd_bufspacethresh && new >= bd->bd_bufspacethresh) 690 bufspace_daemon_wakeup(bd); 691 692 return (0); 693 } 694 695 /* 696 * bufspace_release: 697 * 698 * Release reserved bufspace after bufspace_adjust() has consumed it. 699 */ 700 static void 701 bufspace_release(struct bufdomain *bd, int size) 702 { 703 704 atomic_subtract_long(&bd->bd_bufspace, size); 705 } 706 707 /* 708 * bufspace_wait: 709 * 710 * Wait for bufspace, acting as the buf daemon if a locked vnode is 711 * supplied. bd_wanted must be set prior to polling for space. The 712 * operation must be re-tried on return. 713 */ 714 static void 715 bufspace_wait(struct bufdomain *bd, struct vnode *vp, int gbflags, 716 int slpflag, int slptimeo) 717 { 718 struct thread *td; 719 int error, fl, norunbuf; 720 721 if ((gbflags & GB_NOWAIT_BD) != 0) 722 return; 723 724 td = curthread; 725 BD_LOCK(bd); 726 while (bd->bd_wanted) { 727 if (vp != NULL && vp->v_type != VCHR && 728 (td->td_pflags & TDP_BUFNEED) == 0) { 729 BD_UNLOCK(bd); 730 /* 731 * getblk() is called with a vnode locked, and 732 * some majority of the dirty buffers may as 733 * well belong to the vnode. Flushing the 734 * buffers there would make a progress that 735 * cannot be achieved by the buf_daemon, that 736 * cannot lock the vnode. 737 */ 738 norunbuf = ~(TDP_BUFNEED | TDP_NORUNNINGBUF) | 739 (td->td_pflags & TDP_NORUNNINGBUF); 740 741 /* 742 * Play bufdaemon. The getnewbuf() function 743 * may be called while the thread owns lock 744 * for another dirty buffer for the same 745 * vnode, which makes it impossible to use 746 * VOP_FSYNC() there, due to the buffer lock 747 * recursion. 748 */ 749 td->td_pflags |= TDP_BUFNEED | TDP_NORUNNINGBUF; 750 fl = buf_flush(vp, bd, flushbufqtarget); 751 td->td_pflags &= norunbuf; 752 BD_LOCK(bd); 753 if (fl != 0) 754 continue; 755 if (bd->bd_wanted == 0) 756 break; 757 } 758 error = msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 759 (PRIBIO + 4) | slpflag, "newbuf", slptimeo); 760 if (error != 0) 761 break; 762 } 763 BD_UNLOCK(bd); 764 } 765 766 static void 767 bufspace_daemon_shutdown(void *arg, int howto __unused) 768 { 769 struct bufdomain *bd = arg; 770 int error; 771 772 if (KERNEL_PANICKED()) 773 return; 774 775 BD_RUN_LOCK(bd); 776 bd->bd_shutdown = true; 777 wakeup(&bd->bd_running); 778 error = msleep(&bd->bd_shutdown, BD_RUN_LOCKPTR(bd), 0, 779 "bufspace_shutdown", 60 * hz); 780 BD_RUN_UNLOCK(bd); 781 if (error != 0) 782 printf("bufspacedaemon wait error: %d\n", error); 783 } 784 785 /* 786 * bufspace_daemon: 787 * 788 * buffer space management daemon. Tries to maintain some marginal 789 * amount of free buffer space so that requesting processes neither 790 * block nor work to reclaim buffers. 791 */ 792 static void 793 bufspace_daemon(void *arg) 794 { 795 struct bufdomain *bd = arg; 796 797 EVENTHANDLER_REGISTER(shutdown_pre_sync, bufspace_daemon_shutdown, bd, 798 SHUTDOWN_PRI_LAST + 100); 799 800 BD_RUN_LOCK(bd); 801 while (!bd->bd_shutdown) { 802 BD_RUN_UNLOCK(bd); 803 804 /* 805 * Free buffers from the clean queue until we meet our 806 * targets. 807 * 808 * Theory of operation: The buffer cache is most efficient 809 * when some free buffer headers and space are always 810 * available to getnewbuf(). This daemon attempts to prevent 811 * the excessive blocking and synchronization associated 812 * with shortfall. It goes through three phases according 813 * demand: 814 * 815 * 1) The daemon wakes up voluntarily once per-second 816 * during idle periods when the counters are below 817 * the wakeup thresholds (bufspacethresh, lofreebuffers). 818 * 819 * 2) The daemon wakes up as we cross the thresholds 820 * ahead of any potential blocking. This may bounce 821 * slightly according to the rate of consumption and 822 * release. 823 * 824 * 3) The daemon and consumers are starved for working 825 * clean buffers. This is the 'bufspace' sleep below 826 * which will inefficiently trade bufs with bqrelse 827 * until we return to condition 2. 828 */ 829 while (bd->bd_bufspace > bd->bd_lobufspace || 830 bd->bd_freebuffers < bd->bd_hifreebuffers) { 831 if (buf_recycle(bd, false) != 0) { 832 if (bd_flushall(bd)) 833 continue; 834 /* 835 * Speedup dirty if we've run out of clean 836 * buffers. This is possible in particular 837 * because softdep may held many bufs locked 838 * pending writes to other bufs which are 839 * marked for delayed write, exhausting 840 * clean space until they are written. 841 */ 842 bd_speedup(); 843 BD_LOCK(bd); 844 if (bd->bd_wanted) { 845 msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 846 PRIBIO|PDROP, "bufspace", hz/10); 847 } else 848 BD_UNLOCK(bd); 849 } 850 maybe_yield(); 851 } 852 853 /* 854 * Re-check our limits and sleep. bd_running must be 855 * cleared prior to checking the limits to avoid missed 856 * wakeups. The waker will adjust one of bufspace or 857 * freebuffers prior to checking bd_running. 858 */ 859 BD_RUN_LOCK(bd); 860 if (bd->bd_shutdown) 861 break; 862 atomic_store_int(&bd->bd_running, 0); 863 if (bd->bd_bufspace < bd->bd_bufspacethresh && 864 bd->bd_freebuffers > bd->bd_lofreebuffers) { 865 msleep(&bd->bd_running, BD_RUN_LOCKPTR(bd), 866 PRIBIO, "-", hz); 867 } else { 868 /* Avoid spurious wakeups while running. */ 869 atomic_store_int(&bd->bd_running, 1); 870 } 871 } 872 wakeup(&bd->bd_shutdown); 873 BD_RUN_UNLOCK(bd); 874 kthread_exit(); 875 } 876 877 /* 878 * bufmallocadjust: 879 * 880 * Adjust the reported bufspace for a malloc managed buffer, possibly 881 * waking any waiters. 882 */ 883 static void 884 bufmallocadjust(struct buf *bp, int bufsize) 885 { 886 int diff; 887 888 KASSERT((bp->b_flags & B_MALLOC) != 0, 889 ("bufmallocadjust: non-malloc buf %p", bp)); 890 diff = bufsize - bp->b_bufsize; 891 if (diff < 0) 892 atomic_subtract_long(&bufmallocspace, -diff); 893 else 894 atomic_add_long(&bufmallocspace, diff); 895 bp->b_bufsize = bufsize; 896 } 897 898 /* 899 * runningwakeup: 900 * 901 * Wake up processes that are waiting on asynchronous writes to fall 902 * below lorunningspace. 903 */ 904 static void 905 runningwakeup(void) 906 { 907 908 mtx_lock(&rbreqlock); 909 if (runningbufreq) { 910 runningbufreq = 0; 911 wakeup(&runningbufreq); 912 } 913 mtx_unlock(&rbreqlock); 914 } 915 916 /* 917 * runningbufwakeup: 918 * 919 * Decrement the outstanding write count according. 920 */ 921 void 922 runningbufwakeup(struct buf *bp) 923 { 924 long space, bspace; 925 926 bspace = bp->b_runningbufspace; 927 if (bspace == 0) 928 return; 929 space = atomic_fetchadd_long(&runningbufspace, -bspace); 930 KASSERT(space >= bspace, ("runningbufspace underflow %ld %ld", 931 space, bspace)); 932 bp->b_runningbufspace = 0; 933 /* 934 * Only acquire the lock and wakeup on the transition from exceeding 935 * the threshold to falling below it. 936 */ 937 if (space < lorunningspace) 938 return; 939 if (space - bspace > lorunningspace) 940 return; 941 runningwakeup(); 942 } 943 944 /* 945 * waitrunningbufspace() 946 * 947 * runningbufspace is a measure of the amount of I/O currently 948 * running. This routine is used in async-write situations to 949 * prevent creating huge backups of pending writes to a device. 950 * Only asynchronous writes are governed by this function. 951 * 952 * This does NOT turn an async write into a sync write. It waits 953 * for earlier writes to complete and generally returns before the 954 * caller's write has reached the device. 955 */ 956 void 957 waitrunningbufspace(void) 958 { 959 960 mtx_lock(&rbreqlock); 961 while (runningbufspace > hirunningspace) { 962 runningbufreq = 1; 963 msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0); 964 } 965 mtx_unlock(&rbreqlock); 966 } 967 968 /* 969 * vfs_buf_test_cache: 970 * 971 * Called when a buffer is extended. This function clears the B_CACHE 972 * bit if the newly extended portion of the buffer does not contain 973 * valid data. 974 */ 975 static __inline void 976 vfs_buf_test_cache(struct buf *bp, vm_ooffset_t foff, vm_offset_t off, 977 vm_offset_t size, vm_page_t m) 978 { 979 980 /* 981 * This function and its results are protected by higher level 982 * synchronization requiring vnode and buf locks to page in and 983 * validate pages. 984 */ 985 if (bp->b_flags & B_CACHE) { 986 int base = (foff + off) & PAGE_MASK; 987 if (vm_page_is_valid(m, base, size) == 0) 988 bp->b_flags &= ~B_CACHE; 989 } 990 } 991 992 /* Wake up the buffer daemon if necessary */ 993 static void 994 bd_wakeup(void) 995 { 996 997 mtx_lock(&bdlock); 998 if (bd_request == 0) { 999 bd_request = 1; 1000 wakeup(&bd_request); 1001 } 1002 mtx_unlock(&bdlock); 1003 } 1004 1005 /* 1006 * Adjust the maxbcachbuf tunable. 1007 */ 1008 static void 1009 maxbcachebuf_adjust(void) 1010 { 1011 int i; 1012 1013 /* 1014 * maxbcachebuf must be a power of 2 >= MAXBSIZE. 1015 */ 1016 i = 2; 1017 while (i * 2 <= maxbcachebuf) 1018 i *= 2; 1019 maxbcachebuf = i; 1020 if (maxbcachebuf < MAXBSIZE) 1021 maxbcachebuf = MAXBSIZE; 1022 if (maxbcachebuf > maxphys) 1023 maxbcachebuf = maxphys; 1024 if (bootverbose != 0 && maxbcachebuf != MAXBCACHEBUF) 1025 printf("maxbcachebuf=%d\n", maxbcachebuf); 1026 } 1027 1028 /* 1029 * bd_speedup - speedup the buffer cache flushing code 1030 */ 1031 void 1032 bd_speedup(void) 1033 { 1034 int needwake; 1035 1036 mtx_lock(&bdlock); 1037 needwake = 0; 1038 if (bd_speedupreq == 0 || bd_request == 0) 1039 needwake = 1; 1040 bd_speedupreq = 1; 1041 bd_request = 1; 1042 if (needwake) 1043 wakeup(&bd_request); 1044 mtx_unlock(&bdlock); 1045 } 1046 1047 #ifdef __i386__ 1048 #define TRANSIENT_DENOM 5 1049 #else 1050 #define TRANSIENT_DENOM 10 1051 #endif 1052 1053 /* 1054 * Calculating buffer cache scaling values and reserve space for buffer 1055 * headers. This is called during low level kernel initialization and 1056 * may be called more then once. We CANNOT write to the memory area 1057 * being reserved at this time. 1058 */ 1059 caddr_t 1060 kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est) 1061 { 1062 int tuned_nbuf; 1063 long maxbuf, maxbuf_sz, buf_sz, biotmap_sz; 1064 1065 /* 1066 * With KASAN or KMSAN enabled, the kernel map is shadowed. Account for 1067 * this when sizing maps based on the amount of physical memory 1068 * available. 1069 */ 1070 #if defined(KASAN) 1071 physmem_est = (physmem_est * KASAN_SHADOW_SCALE) / 1072 (KASAN_SHADOW_SCALE + 1); 1073 #elif defined(KMSAN) 1074 physmem_est /= 3; 1075 1076 /* 1077 * KMSAN cannot reliably determine whether buffer data is initialized 1078 * unless it is updated through a KVA mapping. 1079 */ 1080 unmapped_buf_allowed = 0; 1081 #endif 1082 1083 /* 1084 * physmem_est is in pages. Convert it to kilobytes (assumes 1085 * PAGE_SIZE is >= 1K) 1086 */ 1087 physmem_est = physmem_est * (PAGE_SIZE / 1024); 1088 1089 maxbcachebuf_adjust(); 1090 /* 1091 * The nominal buffer size (and minimum KVA allocation) is BKVASIZE. 1092 * For the first 64MB of ram nominally allocate sufficient buffers to 1093 * cover 1/4 of our ram. Beyond the first 64MB allocate additional 1094 * buffers to cover 1/10 of our ram over 64MB. When auto-sizing 1095 * the buffer cache we limit the eventual kva reservation to 1096 * maxbcache bytes. 1097 * 1098 * factor represents the 1/4 x ram conversion. 1099 */ 1100 if (nbuf == 0) { 1101 int factor = 4 * BKVASIZE / 1024; 1102 1103 nbuf = 50; 1104 if (physmem_est > 4096) 1105 nbuf += min((physmem_est - 4096) / factor, 1106 65536 / factor); 1107 if (physmem_est > 65536) 1108 nbuf += min((physmem_est - 65536) * 2 / (factor * 5), 1109 32 * 1024 * 1024 / (factor * 5)); 1110 1111 if (maxbcache && nbuf > maxbcache / BKVASIZE) 1112 nbuf = maxbcache / BKVASIZE; 1113 tuned_nbuf = 1; 1114 } else 1115 tuned_nbuf = 0; 1116 1117 /* XXX Avoid unsigned long overflows later on with maxbufspace. */ 1118 maxbuf = (LONG_MAX / 3) / BKVASIZE; 1119 if (nbuf > maxbuf) { 1120 if (!tuned_nbuf) 1121 printf("Warning: nbufs lowered from %d to %ld\n", nbuf, 1122 maxbuf); 1123 nbuf = maxbuf; 1124 } 1125 1126 /* 1127 * Ideal allocation size for the transient bio submap is 10% 1128 * of the maximal space buffer map. This roughly corresponds 1129 * to the amount of the buffer mapped for typical UFS load. 1130 * 1131 * Clip the buffer map to reserve space for the transient 1132 * BIOs, if its extent is bigger than 90% (80% on i386) of the 1133 * maximum buffer map extent on the platform. 1134 * 1135 * The fall-back to the maxbuf in case of maxbcache unset, 1136 * allows to not trim the buffer KVA for the architectures 1137 * with ample KVA space. 1138 */ 1139 if (bio_transient_maxcnt == 0 && unmapped_buf_allowed) { 1140 maxbuf_sz = maxbcache != 0 ? maxbcache : maxbuf * BKVASIZE; 1141 buf_sz = (long)nbuf * BKVASIZE; 1142 if (buf_sz < maxbuf_sz / TRANSIENT_DENOM * 1143 (TRANSIENT_DENOM - 1)) { 1144 /* 1145 * There is more KVA than memory. Do not 1146 * adjust buffer map size, and assign the rest 1147 * of maxbuf to transient map. 1148 */ 1149 biotmap_sz = maxbuf_sz - buf_sz; 1150 } else { 1151 /* 1152 * Buffer map spans all KVA we could afford on 1153 * this platform. Give 10% (20% on i386) of 1154 * the buffer map to the transient bio map. 1155 */ 1156 biotmap_sz = buf_sz / TRANSIENT_DENOM; 1157 buf_sz -= biotmap_sz; 1158 } 1159 if (biotmap_sz / INT_MAX > maxphys) 1160 bio_transient_maxcnt = INT_MAX; 1161 else 1162 bio_transient_maxcnt = biotmap_sz / maxphys; 1163 /* 1164 * Artificially limit to 1024 simultaneous in-flight I/Os 1165 * using the transient mapping. 1166 */ 1167 if (bio_transient_maxcnt > 1024) 1168 bio_transient_maxcnt = 1024; 1169 if (tuned_nbuf) 1170 nbuf = buf_sz / BKVASIZE; 1171 } 1172 1173 if (nswbuf == 0) { 1174 /* 1175 * Pager buffers are allocated for short periods, so scale the 1176 * number of reserved buffers based on the number of CPUs rather 1177 * than amount of memory. 1178 */ 1179 nswbuf = min(nbuf / 4, 32 * mp_ncpus); 1180 if (nswbuf < NSWBUF_MIN) 1181 nswbuf = NSWBUF_MIN; 1182 } 1183 1184 /* 1185 * Reserve space for the buffer cache buffers 1186 */ 1187 buf = (char *)v; 1188 v = (caddr_t)buf + (sizeof(struct buf) + sizeof(vm_page_t) * 1189 atop(maxbcachebuf)) * nbuf; 1190 1191 return (v); 1192 } 1193 1194 /* 1195 * Single global constant for BUF_WMESG, to avoid getting multiple 1196 * references. 1197 */ 1198 static const char buf_wmesg[] = "bufwait"; 1199 1200 /* Initialize the buffer subsystem. Called before use of any buffers. */ 1201 void 1202 bufinit(void) 1203 { 1204 struct buf *bp; 1205 int i; 1206 1207 TSENTER(); 1208 KASSERT(maxbcachebuf >= MAXBSIZE, 1209 ("maxbcachebuf (%d) must be >= MAXBSIZE (%d)\n", maxbcachebuf, 1210 MAXBSIZE)); 1211 bq_init(&bqempty, QUEUE_EMPTY, -1, "bufq empty lock"); 1212 mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF); 1213 mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF); 1214 mtx_init(&bdirtylock, "dirty buf lock", NULL, MTX_DEF); 1215 1216 unmapped_buf = (caddr_t)kva_alloc(maxphys); 1217 #ifdef INVARIANTS 1218 poisoned_buf = unmapped_buf; 1219 #endif 1220 1221 /* finally, initialize each buffer header and stick on empty q */ 1222 for (i = 0; i < nbuf; i++) { 1223 bp = nbufp(i); 1224 bzero(bp, sizeof(*bp) + sizeof(vm_page_t) * atop(maxbcachebuf)); 1225 bp->b_flags = B_INVAL; 1226 bp->b_rcred = NOCRED; 1227 bp->b_wcred = NOCRED; 1228 bp->b_qindex = QUEUE_NONE; 1229 bp->b_domain = -1; 1230 bp->b_subqueue = mp_maxid + 1; 1231 bp->b_xflags = 0; 1232 bp->b_data = bp->b_kvabase = unmapped_buf; 1233 LIST_INIT(&bp->b_dep); 1234 BUF_LOCKINIT(bp, buf_wmesg); 1235 bq_insert(&bqempty, bp, false); 1236 } 1237 1238 /* 1239 * maxbufspace is the absolute maximum amount of buffer space we are 1240 * allowed to reserve in KVM and in real terms. The absolute maximum 1241 * is nominally used by metadata. hibufspace is the nominal maximum 1242 * used by most other requests. The differential is required to 1243 * ensure that metadata deadlocks don't occur. 1244 * 1245 * maxbufspace is based on BKVASIZE. Allocating buffers larger then 1246 * this may result in KVM fragmentation which is not handled optimally 1247 * by the system. XXX This is less true with vmem. We could use 1248 * PAGE_SIZE. 1249 */ 1250 maxbufspace = (long)nbuf * BKVASIZE; 1251 hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - maxbcachebuf * 10); 1252 lobufspace = (hibufspace / 20) * 19; /* 95% */ 1253 bufspacethresh = lobufspace + (hibufspace - lobufspace) / 2; 1254 1255 /* 1256 * Note: The 16 MiB upper limit for hirunningspace was chosen 1257 * arbitrarily and may need further tuning. It corresponds to 1258 * 128 outstanding write IO requests (if IO size is 128 KiB), 1259 * which fits with many RAID controllers' tagged queuing limits. 1260 * The lower 1 MiB limit is the historical upper limit for 1261 * hirunningspace. 1262 */ 1263 hirunningspace = lmax(lmin(roundup(hibufspace / 64, maxbcachebuf), 1264 16 * 1024 * 1024), 1024 * 1024); 1265 lorunningspace = roundup((hirunningspace * 2) / 3, maxbcachebuf); 1266 1267 /* 1268 * Limit the amount of malloc memory since it is wired permanently into 1269 * the kernel space. Even though this is accounted for in the buffer 1270 * allocation, we don't want the malloced region to grow uncontrolled. 1271 * The malloc scheme improves memory utilization significantly on 1272 * average (small) directories. 1273 */ 1274 maxbufmallocspace = hibufspace / 20; 1275 1276 /* 1277 * Reduce the chance of a deadlock occurring by limiting the number 1278 * of delayed-write dirty buffers we allow to stack up. 1279 */ 1280 hidirtybuffers = nbuf / 4 + 20; 1281 dirtybufthresh = hidirtybuffers * 9 / 10; 1282 /* 1283 * To support extreme low-memory systems, make sure hidirtybuffers 1284 * cannot eat up all available buffer space. This occurs when our 1285 * minimum cannot be met. We try to size hidirtybuffers to 3/4 our 1286 * buffer space assuming BKVASIZE'd buffers. 1287 */ 1288 while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) { 1289 hidirtybuffers >>= 1; 1290 } 1291 lodirtybuffers = hidirtybuffers / 2; 1292 1293 /* 1294 * lofreebuffers should be sufficient to avoid stalling waiting on 1295 * buf headers under heavy utilization. The bufs in per-cpu caches 1296 * are counted as free but will be unavailable to threads executing 1297 * on other cpus. 1298 * 1299 * hifreebuffers is the free target for the bufspace daemon. This 1300 * should be set appropriately to limit work per-iteration. 1301 */ 1302 lofreebuffers = MIN((nbuf / 25) + (20 * mp_ncpus), 128 * mp_ncpus); 1303 hifreebuffers = (3 * lofreebuffers) / 2; 1304 numfreebuffers = nbuf; 1305 1306 /* Setup the kva and free list allocators. */ 1307 vmem_set_reclaim(buffer_arena, bufkva_reclaim); 1308 buf_zone = uma_zcache_create("buf free cache", 1309 sizeof(struct buf) + sizeof(vm_page_t) * atop(maxbcachebuf), 1310 NULL, NULL, NULL, NULL, buf_import, buf_release, NULL, 0); 1311 1312 /* 1313 * Size the clean queue according to the amount of buffer space. 1314 * One queue per-256mb up to the max. More queues gives better 1315 * concurrency but less accurate LRU. 1316 */ 1317 buf_domains = MIN(howmany(maxbufspace, 256*1024*1024), BUF_DOMAINS); 1318 for (i = 0 ; i < buf_domains; i++) { 1319 struct bufdomain *bd; 1320 1321 bd = &bdomain[i]; 1322 bd_init(bd); 1323 bd->bd_freebuffers = nbuf / buf_domains; 1324 bd->bd_hifreebuffers = hifreebuffers / buf_domains; 1325 bd->bd_lofreebuffers = lofreebuffers / buf_domains; 1326 bd->bd_bufspace = 0; 1327 bd->bd_maxbufspace = maxbufspace / buf_domains; 1328 bd->bd_hibufspace = hibufspace / buf_domains; 1329 bd->bd_lobufspace = lobufspace / buf_domains; 1330 bd->bd_bufspacethresh = bufspacethresh / buf_domains; 1331 bd->bd_numdirtybuffers = 0; 1332 bd->bd_hidirtybuffers = hidirtybuffers / buf_domains; 1333 bd->bd_lodirtybuffers = lodirtybuffers / buf_domains; 1334 bd->bd_dirtybufthresh = dirtybufthresh / buf_domains; 1335 /* Don't allow more than 2% of bufs in the per-cpu caches. */ 1336 bd->bd_lim = nbuf / buf_domains / 50 / mp_ncpus; 1337 } 1338 getnewbufcalls = counter_u64_alloc(M_WAITOK); 1339 getnewbufrestarts = counter_u64_alloc(M_WAITOK); 1340 mappingrestarts = counter_u64_alloc(M_WAITOK); 1341 numbufallocfails = counter_u64_alloc(M_WAITOK); 1342 notbufdflushes = counter_u64_alloc(M_WAITOK); 1343 buffreekvacnt = counter_u64_alloc(M_WAITOK); 1344 bufdefragcnt = counter_u64_alloc(M_WAITOK); 1345 bufkvaspace = counter_u64_alloc(M_WAITOK); 1346 TSEXIT(); 1347 } 1348 1349 #ifdef INVARIANTS 1350 static inline void 1351 vfs_buf_check_mapped(struct buf *bp) 1352 { 1353 1354 KASSERT(bp->b_kvabase != unmapped_buf, 1355 ("mapped buf: b_kvabase was not updated %p", bp)); 1356 KASSERT(bp->b_data != unmapped_buf, 1357 ("mapped buf: b_data was not updated %p", bp)); 1358 KASSERT(bp->b_data < unmapped_buf || bp->b_data >= unmapped_buf + 1359 maxphys, ("b_data + b_offset unmapped %p", bp)); 1360 } 1361 1362 static inline void 1363 vfs_buf_check_unmapped(struct buf *bp) 1364 { 1365 1366 KASSERT(bp->b_data == unmapped_buf, 1367 ("unmapped buf: corrupted b_data %p", bp)); 1368 } 1369 1370 #define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp) 1371 #define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp) 1372 #else 1373 #define BUF_CHECK_MAPPED(bp) do {} while (0) 1374 #define BUF_CHECK_UNMAPPED(bp) do {} while (0) 1375 #endif 1376 1377 static int 1378 isbufbusy(struct buf *bp) 1379 { 1380 if (((bp->b_flags & B_INVAL) == 0 && BUF_ISLOCKED(bp)) || 1381 ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)) 1382 return (1); 1383 return (0); 1384 } 1385 1386 /* 1387 * Shutdown the system cleanly to prepare for reboot, halt, or power off. 1388 */ 1389 void 1390 bufshutdown(int show_busybufs) 1391 { 1392 static int first_buf_printf = 1; 1393 struct buf *bp; 1394 int i, iter, nbusy, pbusy; 1395 #ifndef PREEMPTION 1396 int subiter; 1397 #endif 1398 1399 /* 1400 * Sync filesystems for shutdown 1401 */ 1402 wdog_kern_pat(WD_LASTVAL); 1403 kern_sync(curthread); 1404 1405 /* 1406 * With soft updates, some buffers that are 1407 * written will be remarked as dirty until other 1408 * buffers are written. 1409 */ 1410 for (iter = pbusy = 0; iter < 20; iter++) { 1411 nbusy = 0; 1412 for (i = nbuf - 1; i >= 0; i--) { 1413 bp = nbufp(i); 1414 if (isbufbusy(bp)) 1415 nbusy++; 1416 } 1417 if (nbusy == 0) { 1418 if (first_buf_printf) 1419 printf("All buffers synced."); 1420 break; 1421 } 1422 if (first_buf_printf) { 1423 printf("Syncing disks, buffers remaining... "); 1424 first_buf_printf = 0; 1425 } 1426 printf("%d ", nbusy); 1427 if (nbusy < pbusy) 1428 iter = 0; 1429 pbusy = nbusy; 1430 1431 wdog_kern_pat(WD_LASTVAL); 1432 kern_sync(curthread); 1433 1434 #ifdef PREEMPTION 1435 /* 1436 * Spin for a while to allow interrupt threads to run. 1437 */ 1438 DELAY(50000 * iter); 1439 #else 1440 /* 1441 * Context switch several times to allow interrupt 1442 * threads to run. 1443 */ 1444 for (subiter = 0; subiter < 50 * iter; subiter++) { 1445 sched_relinquish(curthread); 1446 DELAY(1000); 1447 } 1448 #endif 1449 } 1450 printf("\n"); 1451 /* 1452 * Count only busy local buffers to prevent forcing 1453 * a fsck if we're just a client of a wedged NFS server 1454 */ 1455 nbusy = 0; 1456 for (i = nbuf - 1; i >= 0; i--) { 1457 bp = nbufp(i); 1458 if (isbufbusy(bp)) { 1459 #if 0 1460 /* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */ 1461 if (bp->b_dev == NULL) { 1462 TAILQ_REMOVE(&mountlist, 1463 bp->b_vp->v_mount, mnt_list); 1464 continue; 1465 } 1466 #endif 1467 nbusy++; 1468 if (show_busybufs > 0) { 1469 printf( 1470 "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:", 1471 nbusy, bp, bp->b_vp, bp->b_flags, 1472 (intmax_t)bp->b_blkno, 1473 (intmax_t)bp->b_lblkno); 1474 BUF_LOCKPRINTINFO(bp); 1475 if (show_busybufs > 1) 1476 vn_printf(bp->b_vp, 1477 "vnode content: "); 1478 } 1479 } 1480 } 1481 if (nbusy) { 1482 /* 1483 * Failed to sync all blocks. Indicate this and don't 1484 * unmount filesystems (thus forcing an fsck on reboot). 1485 */ 1486 BOOTTRACE("shutdown failed to sync buffers"); 1487 printf("Giving up on %d buffers\n", nbusy); 1488 DELAY(5000000); /* 5 seconds */ 1489 swapoff_all(); 1490 } else { 1491 BOOTTRACE("shutdown sync complete"); 1492 if (!first_buf_printf) 1493 printf("Final sync complete\n"); 1494 1495 /* 1496 * Unmount filesystems and perform swapoff, to quiesce 1497 * the system as much as possible. In particular, no 1498 * I/O should be initiated from top levels since it 1499 * might be abruptly terminated by reset, or otherwise 1500 * erronously handled because other parts of the 1501 * system are disabled. 1502 * 1503 * Swapoff before unmount, because file-backed swap is 1504 * non-operational after unmount of the underlying 1505 * filesystem. 1506 */ 1507 if (!KERNEL_PANICKED()) { 1508 swapoff_all(); 1509 vfs_unmountall(); 1510 } 1511 BOOTTRACE("shutdown unmounted all filesystems"); 1512 } 1513 DELAY(100000); /* wait for console output to finish */ 1514 } 1515 1516 static void 1517 bpmap_qenter(struct buf *bp) 1518 { 1519 1520 BUF_CHECK_MAPPED(bp); 1521 1522 /* 1523 * bp->b_data is relative to bp->b_offset, but 1524 * bp->b_offset may be offset into the first page. 1525 */ 1526 bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data); 1527 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 1528 bp->b_data = (caddr_t)((vm_offset_t)bp->b_data | 1529 (vm_offset_t)(bp->b_offset & PAGE_MASK)); 1530 } 1531 1532 static inline struct bufdomain * 1533 bufdomain(struct buf *bp) 1534 { 1535 1536 return (&bdomain[bp->b_domain]); 1537 } 1538 1539 static struct bufqueue * 1540 bufqueue(struct buf *bp) 1541 { 1542 1543 switch (bp->b_qindex) { 1544 case QUEUE_NONE: 1545 /* FALLTHROUGH */ 1546 case QUEUE_SENTINEL: 1547 return (NULL); 1548 case QUEUE_EMPTY: 1549 return (&bqempty); 1550 case QUEUE_DIRTY: 1551 return (&bufdomain(bp)->bd_dirtyq); 1552 case QUEUE_CLEAN: 1553 return (&bufdomain(bp)->bd_subq[bp->b_subqueue]); 1554 default: 1555 break; 1556 } 1557 panic("bufqueue(%p): Unhandled type %d\n", bp, bp->b_qindex); 1558 } 1559 1560 /* 1561 * Return the locked bufqueue that bp is a member of. 1562 */ 1563 static struct bufqueue * 1564 bufqueue_acquire(struct buf *bp) 1565 { 1566 struct bufqueue *bq, *nbq; 1567 1568 /* 1569 * bp can be pushed from a per-cpu queue to the 1570 * cleanq while we're waiting on the lock. Retry 1571 * if the queues don't match. 1572 */ 1573 bq = bufqueue(bp); 1574 BQ_LOCK(bq); 1575 for (;;) { 1576 nbq = bufqueue(bp); 1577 if (bq == nbq) 1578 break; 1579 BQ_UNLOCK(bq); 1580 BQ_LOCK(nbq); 1581 bq = nbq; 1582 } 1583 return (bq); 1584 } 1585 1586 /* 1587 * binsfree: 1588 * 1589 * Insert the buffer into the appropriate free list. Requires a 1590 * locked buffer on entry and buffer is unlocked before return. 1591 */ 1592 static void 1593 binsfree(struct buf *bp, int qindex) 1594 { 1595 struct bufdomain *bd; 1596 struct bufqueue *bq; 1597 1598 KASSERT(qindex == QUEUE_CLEAN || qindex == QUEUE_DIRTY, 1599 ("binsfree: Invalid qindex %d", qindex)); 1600 BUF_ASSERT_XLOCKED(bp); 1601 1602 /* 1603 * Handle delayed bremfree() processing. 1604 */ 1605 if (bp->b_flags & B_REMFREE) { 1606 if (bp->b_qindex == qindex) { 1607 bp->b_flags |= B_REUSE; 1608 bp->b_flags &= ~B_REMFREE; 1609 BUF_UNLOCK(bp); 1610 return; 1611 } 1612 bq = bufqueue_acquire(bp); 1613 bq_remove(bq, bp); 1614 BQ_UNLOCK(bq); 1615 } 1616 bd = bufdomain(bp); 1617 if (qindex == QUEUE_CLEAN) { 1618 if (bd->bd_lim != 0) 1619 bq = &bd->bd_subq[PCPU_GET(cpuid)]; 1620 else 1621 bq = bd->bd_cleanq; 1622 } else 1623 bq = &bd->bd_dirtyq; 1624 bq_insert(bq, bp, true); 1625 } 1626 1627 /* 1628 * buf_free: 1629 * 1630 * Free a buffer to the buf zone once it no longer has valid contents. 1631 */ 1632 static void 1633 buf_free(struct buf *bp) 1634 { 1635 1636 if (bp->b_flags & B_REMFREE) 1637 bremfreef(bp); 1638 if (bp->b_vflags & BV_BKGRDINPROG) 1639 panic("losing buffer 1"); 1640 if (bp->b_rcred != NOCRED) { 1641 crfree(bp->b_rcred); 1642 bp->b_rcred = NOCRED; 1643 } 1644 if (bp->b_wcred != NOCRED) { 1645 crfree(bp->b_wcred); 1646 bp->b_wcred = NOCRED; 1647 } 1648 if (!LIST_EMPTY(&bp->b_dep)) 1649 buf_deallocate(bp); 1650 bufkva_free(bp); 1651 atomic_add_int(&bufdomain(bp)->bd_freebuffers, 1); 1652 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1653 BUF_UNLOCK(bp); 1654 uma_zfree(buf_zone, bp); 1655 } 1656 1657 /* 1658 * buf_import: 1659 * 1660 * Import bufs into the uma cache from the buf list. The system still 1661 * expects a static array of bufs and much of the synchronization 1662 * around bufs assumes type stable storage. As a result, UMA is used 1663 * only as a per-cpu cache of bufs still maintained on a global list. 1664 */ 1665 static int 1666 buf_import(void *arg, void **store, int cnt, int domain, int flags) 1667 { 1668 struct buf *bp; 1669 int i; 1670 1671 BQ_LOCK(&bqempty); 1672 for (i = 0; i < cnt; i++) { 1673 bp = TAILQ_FIRST(&bqempty.bq_queue); 1674 if (bp == NULL) 1675 break; 1676 bq_remove(&bqempty, bp); 1677 store[i] = bp; 1678 } 1679 BQ_UNLOCK(&bqempty); 1680 1681 return (i); 1682 } 1683 1684 /* 1685 * buf_release: 1686 * 1687 * Release bufs from the uma cache back to the buffer queues. 1688 */ 1689 static void 1690 buf_release(void *arg, void **store, int cnt) 1691 { 1692 struct bufqueue *bq; 1693 struct buf *bp; 1694 int i; 1695 1696 bq = &bqempty; 1697 BQ_LOCK(bq); 1698 for (i = 0; i < cnt; i++) { 1699 bp = store[i]; 1700 /* Inline bq_insert() to batch locking. */ 1701 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1702 bp->b_flags &= ~(B_AGE | B_REUSE); 1703 bq->bq_len++; 1704 bp->b_qindex = bq->bq_index; 1705 } 1706 BQ_UNLOCK(bq); 1707 } 1708 1709 /* 1710 * buf_alloc: 1711 * 1712 * Allocate an empty buffer header. 1713 */ 1714 static struct buf * 1715 buf_alloc(struct bufdomain *bd) 1716 { 1717 struct buf *bp; 1718 int freebufs, error; 1719 1720 /* 1721 * We can only run out of bufs in the buf zone if the average buf 1722 * is less than BKVASIZE. In this case the actual wait/block will 1723 * come from buf_reycle() failing to flush one of these small bufs. 1724 */ 1725 bp = NULL; 1726 freebufs = atomic_fetchadd_int(&bd->bd_freebuffers, -1); 1727 if (freebufs > 0) 1728 bp = uma_zalloc(buf_zone, M_NOWAIT); 1729 if (bp == NULL) { 1730 atomic_add_int(&bd->bd_freebuffers, 1); 1731 bufspace_daemon_wakeup(bd); 1732 counter_u64_add(numbufallocfails, 1); 1733 return (NULL); 1734 } 1735 /* 1736 * Wake-up the bufspace daemon on transition below threshold. 1737 */ 1738 if (freebufs == bd->bd_lofreebuffers) 1739 bufspace_daemon_wakeup(bd); 1740 1741 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL); 1742 KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, 1743 error)); 1744 (void)error; 1745 1746 KASSERT(bp->b_vp == NULL, 1747 ("bp: %p still has vnode %p.", bp, bp->b_vp)); 1748 KASSERT((bp->b_flags & (B_DELWRI | B_NOREUSE)) == 0, 1749 ("invalid buffer %p flags %#x", bp, bp->b_flags)); 1750 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0, 1751 ("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags)); 1752 KASSERT(bp->b_npages == 0, 1753 ("bp: %p still has %d vm pages\n", bp, bp->b_npages)); 1754 KASSERT(bp->b_kvasize == 0, ("bp: %p still has kva\n", bp)); 1755 KASSERT(bp->b_bufsize == 0, ("bp: %p still has bufspace\n", bp)); 1756 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1757 1758 bp->b_domain = BD_DOMAIN(bd); 1759 bp->b_flags = 0; 1760 bp->b_ioflags = 0; 1761 bp->b_xflags = 0; 1762 bp->b_vflags = 0; 1763 bp->b_vp = NULL; 1764 bp->b_blkno = bp->b_lblkno = 0; 1765 bp->b_offset = NOOFFSET; 1766 bp->b_iodone = 0; 1767 bp->b_error = 0; 1768 bp->b_resid = 0; 1769 bp->b_bcount = 0; 1770 bp->b_npages = 0; 1771 bp->b_dirtyoff = bp->b_dirtyend = 0; 1772 bp->b_bufobj = NULL; 1773 bp->b_data = bp->b_kvabase = unmapped_buf; 1774 bp->b_fsprivate1 = NULL; 1775 bp->b_fsprivate2 = NULL; 1776 bp->b_fsprivate3 = NULL; 1777 LIST_INIT(&bp->b_dep); 1778 1779 return (bp); 1780 } 1781 1782 /* 1783 * buf_recycle: 1784 * 1785 * Free a buffer from the given bufqueue. kva controls whether the 1786 * freed buf must own some kva resources. This is used for 1787 * defragmenting. 1788 */ 1789 static int 1790 buf_recycle(struct bufdomain *bd, bool kva) 1791 { 1792 struct bufqueue *bq; 1793 struct buf *bp, *nbp; 1794 1795 if (kva) 1796 counter_u64_add(bufdefragcnt, 1); 1797 nbp = NULL; 1798 bq = bd->bd_cleanq; 1799 BQ_LOCK(bq); 1800 KASSERT(BQ_LOCKPTR(bq) == BD_LOCKPTR(bd), 1801 ("buf_recycle: Locks don't match")); 1802 nbp = TAILQ_FIRST(&bq->bq_queue); 1803 1804 /* 1805 * Run scan, possibly freeing data and/or kva mappings on the fly 1806 * depending. 1807 */ 1808 while ((bp = nbp) != NULL) { 1809 /* 1810 * Calculate next bp (we can only use it if we do not 1811 * release the bqlock). 1812 */ 1813 nbp = TAILQ_NEXT(bp, b_freelist); 1814 1815 /* 1816 * If we are defragging then we need a buffer with 1817 * some kva to reclaim. 1818 */ 1819 if (kva && bp->b_kvasize == 0) 1820 continue; 1821 1822 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 1823 continue; 1824 1825 /* 1826 * Implement a second chance algorithm for frequently 1827 * accessed buffers. 1828 */ 1829 if ((bp->b_flags & B_REUSE) != 0) { 1830 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1831 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1832 bp->b_flags &= ~B_REUSE; 1833 BUF_UNLOCK(bp); 1834 continue; 1835 } 1836 1837 /* 1838 * Skip buffers with background writes in progress. 1839 */ 1840 if ((bp->b_vflags & BV_BKGRDINPROG) != 0) { 1841 BUF_UNLOCK(bp); 1842 continue; 1843 } 1844 1845 KASSERT(bp->b_qindex == QUEUE_CLEAN, 1846 ("buf_recycle: inconsistent queue %d bp %p", 1847 bp->b_qindex, bp)); 1848 KASSERT(bp->b_domain == BD_DOMAIN(bd), 1849 ("getnewbuf: queue domain %d doesn't match request %d", 1850 bp->b_domain, (int)BD_DOMAIN(bd))); 1851 /* 1852 * NOTE: nbp is now entirely invalid. We can only restart 1853 * the scan from this point on. 1854 */ 1855 bq_remove(bq, bp); 1856 BQ_UNLOCK(bq); 1857 1858 /* 1859 * Requeue the background write buffer with error and 1860 * restart the scan. 1861 */ 1862 if ((bp->b_vflags & BV_BKGRDERR) != 0) { 1863 bqrelse(bp); 1864 BQ_LOCK(bq); 1865 nbp = TAILQ_FIRST(&bq->bq_queue); 1866 continue; 1867 } 1868 bp->b_flags |= B_INVAL; 1869 brelse(bp); 1870 return (0); 1871 } 1872 bd->bd_wanted = 1; 1873 BQ_UNLOCK(bq); 1874 1875 return (ENOBUFS); 1876 } 1877 1878 /* 1879 * bremfree: 1880 * 1881 * Mark the buffer for removal from the appropriate free list. 1882 * 1883 */ 1884 void 1885 bremfree(struct buf *bp) 1886 { 1887 1888 CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1889 KASSERT((bp->b_flags & B_REMFREE) == 0, 1890 ("bremfree: buffer %p already marked for delayed removal.", bp)); 1891 KASSERT(bp->b_qindex != QUEUE_NONE, 1892 ("bremfree: buffer %p not on a queue.", bp)); 1893 BUF_ASSERT_XLOCKED(bp); 1894 1895 bp->b_flags |= B_REMFREE; 1896 } 1897 1898 /* 1899 * bremfreef: 1900 * 1901 * Force an immediate removal from a free list. Used only in nfs when 1902 * it abuses the b_freelist pointer. 1903 */ 1904 void 1905 bremfreef(struct buf *bp) 1906 { 1907 struct bufqueue *bq; 1908 1909 bq = bufqueue_acquire(bp); 1910 bq_remove(bq, bp); 1911 BQ_UNLOCK(bq); 1912 } 1913 1914 static void 1915 bq_init(struct bufqueue *bq, int qindex, int subqueue, const char *lockname) 1916 { 1917 1918 mtx_init(&bq->bq_lock, lockname, NULL, MTX_DEF); 1919 TAILQ_INIT(&bq->bq_queue); 1920 bq->bq_len = 0; 1921 bq->bq_index = qindex; 1922 bq->bq_subqueue = subqueue; 1923 } 1924 1925 static void 1926 bd_init(struct bufdomain *bd) 1927 { 1928 int i; 1929 1930 /* Per-CPU clean buf queues, plus one global queue. */ 1931 bd->bd_subq = mallocarray(mp_maxid + 2, sizeof(struct bufqueue), 1932 M_BIOBUF, M_WAITOK | M_ZERO); 1933 bd->bd_cleanq = &bd->bd_subq[mp_maxid + 1]; 1934 bq_init(bd->bd_cleanq, QUEUE_CLEAN, mp_maxid + 1, "bufq clean lock"); 1935 bq_init(&bd->bd_dirtyq, QUEUE_DIRTY, -1, "bufq dirty lock"); 1936 for (i = 0; i <= mp_maxid; i++) 1937 bq_init(&bd->bd_subq[i], QUEUE_CLEAN, i, 1938 "bufq clean subqueue lock"); 1939 mtx_init(&bd->bd_run_lock, "bufspace daemon run lock", NULL, MTX_DEF); 1940 } 1941 1942 /* 1943 * bq_remove: 1944 * 1945 * Removes a buffer from the free list, must be called with the 1946 * correct qlock held. 1947 */ 1948 static void 1949 bq_remove(struct bufqueue *bq, struct buf *bp) 1950 { 1951 1952 CTR3(KTR_BUF, "bq_remove(%p) vp %p flags %X", 1953 bp, bp->b_vp, bp->b_flags); 1954 KASSERT(bp->b_qindex != QUEUE_NONE, 1955 ("bq_remove: buffer %p not on a queue.", bp)); 1956 KASSERT(bufqueue(bp) == bq, 1957 ("bq_remove: Remove buffer %p from wrong queue.", bp)); 1958 1959 BQ_ASSERT_LOCKED(bq); 1960 if (bp->b_qindex != QUEUE_EMPTY) { 1961 BUF_ASSERT_XLOCKED(bp); 1962 } 1963 KASSERT(bq->bq_len >= 1, 1964 ("queue %d underflow", bp->b_qindex)); 1965 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1966 bq->bq_len--; 1967 bp->b_qindex = QUEUE_NONE; 1968 bp->b_flags &= ~(B_REMFREE | B_REUSE); 1969 } 1970 1971 static void 1972 bd_flush(struct bufdomain *bd, struct bufqueue *bq) 1973 { 1974 struct buf *bp; 1975 1976 BQ_ASSERT_LOCKED(bq); 1977 if (bq != bd->bd_cleanq) { 1978 BD_LOCK(bd); 1979 while ((bp = TAILQ_FIRST(&bq->bq_queue)) != NULL) { 1980 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1981 TAILQ_INSERT_TAIL(&bd->bd_cleanq->bq_queue, bp, 1982 b_freelist); 1983 bp->b_subqueue = bd->bd_cleanq->bq_subqueue; 1984 } 1985 bd->bd_cleanq->bq_len += bq->bq_len; 1986 bq->bq_len = 0; 1987 } 1988 if (bd->bd_wanted) { 1989 bd->bd_wanted = 0; 1990 wakeup(&bd->bd_wanted); 1991 } 1992 if (bq != bd->bd_cleanq) 1993 BD_UNLOCK(bd); 1994 } 1995 1996 static int 1997 bd_flushall(struct bufdomain *bd) 1998 { 1999 struct bufqueue *bq; 2000 int flushed; 2001 int i; 2002 2003 if (bd->bd_lim == 0) 2004 return (0); 2005 flushed = 0; 2006 for (i = 0; i <= mp_maxid; i++) { 2007 bq = &bd->bd_subq[i]; 2008 if (bq->bq_len == 0) 2009 continue; 2010 BQ_LOCK(bq); 2011 bd_flush(bd, bq); 2012 BQ_UNLOCK(bq); 2013 flushed++; 2014 } 2015 2016 return (flushed); 2017 } 2018 2019 static void 2020 bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock) 2021 { 2022 struct bufdomain *bd; 2023 2024 if (bp->b_qindex != QUEUE_NONE) 2025 panic("bq_insert: free buffer %p onto another queue?", bp); 2026 2027 bd = bufdomain(bp); 2028 if (bp->b_flags & B_AGE) { 2029 /* Place this buf directly on the real queue. */ 2030 if (bq->bq_index == QUEUE_CLEAN) 2031 bq = bd->bd_cleanq; 2032 BQ_LOCK(bq); 2033 TAILQ_INSERT_HEAD(&bq->bq_queue, bp, b_freelist); 2034 } else { 2035 BQ_LOCK(bq); 2036 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 2037 } 2038 bp->b_flags &= ~(B_AGE | B_REUSE); 2039 bq->bq_len++; 2040 bp->b_qindex = bq->bq_index; 2041 bp->b_subqueue = bq->bq_subqueue; 2042 2043 /* 2044 * Unlock before we notify so that we don't wakeup a waiter that 2045 * fails a trylock on the buf and sleeps again. 2046 */ 2047 if (unlock) 2048 BUF_UNLOCK(bp); 2049 2050 if (bp->b_qindex == QUEUE_CLEAN) { 2051 /* 2052 * Flush the per-cpu queue and notify any waiters. 2053 */ 2054 if (bd->bd_wanted || (bq != bd->bd_cleanq && 2055 bq->bq_len >= bd->bd_lim)) 2056 bd_flush(bd, bq); 2057 } 2058 BQ_UNLOCK(bq); 2059 } 2060 2061 /* 2062 * bufkva_free: 2063 * 2064 * Free the kva allocation for a buffer. 2065 * 2066 */ 2067 static void 2068 bufkva_free(struct buf *bp) 2069 { 2070 2071 #ifdef INVARIANTS 2072 if (bp->b_kvasize == 0) { 2073 KASSERT(bp->b_kvabase == unmapped_buf && 2074 bp->b_data == unmapped_buf, 2075 ("Leaked KVA space on %p", bp)); 2076 } else if (buf_mapped(bp)) 2077 BUF_CHECK_MAPPED(bp); 2078 else 2079 BUF_CHECK_UNMAPPED(bp); 2080 #endif 2081 if (bp->b_kvasize == 0) 2082 return; 2083 2084 vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, bp->b_kvasize); 2085 counter_u64_add(bufkvaspace, -bp->b_kvasize); 2086 counter_u64_add(buffreekvacnt, 1); 2087 bp->b_data = bp->b_kvabase = unmapped_buf; 2088 bp->b_kvasize = 0; 2089 } 2090 2091 /* 2092 * bufkva_alloc: 2093 * 2094 * Allocate the buffer KVA and set b_kvasize and b_kvabase. 2095 */ 2096 static int 2097 bufkva_alloc(struct buf *bp, int maxsize, int gbflags) 2098 { 2099 vm_offset_t addr; 2100 int error; 2101 2102 KASSERT((gbflags & GB_UNMAPPED) == 0 || (gbflags & GB_KVAALLOC) != 0, 2103 ("Invalid gbflags 0x%x in %s", gbflags, __func__)); 2104 MPASS((bp->b_flags & B_MAXPHYS) == 0); 2105 KASSERT(maxsize <= maxbcachebuf, 2106 ("bufkva_alloc kva too large %d %u", maxsize, maxbcachebuf)); 2107 2108 bufkva_free(bp); 2109 2110 addr = 0; 2111 error = vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr); 2112 if (error != 0) { 2113 /* 2114 * Buffer map is too fragmented. Request the caller 2115 * to defragment the map. 2116 */ 2117 return (error); 2118 } 2119 bp->b_kvabase = (caddr_t)addr; 2120 bp->b_kvasize = maxsize; 2121 counter_u64_add(bufkvaspace, bp->b_kvasize); 2122 if ((gbflags & GB_UNMAPPED) != 0) { 2123 bp->b_data = unmapped_buf; 2124 BUF_CHECK_UNMAPPED(bp); 2125 } else { 2126 bp->b_data = bp->b_kvabase; 2127 BUF_CHECK_MAPPED(bp); 2128 } 2129 return (0); 2130 } 2131 2132 /* 2133 * bufkva_reclaim: 2134 * 2135 * Reclaim buffer kva by freeing buffers holding kva. This is a vmem 2136 * callback that fires to avoid returning failure. 2137 */ 2138 static void 2139 bufkva_reclaim(vmem_t *vmem, int flags) 2140 { 2141 bool done; 2142 int q; 2143 int i; 2144 2145 done = false; 2146 for (i = 0; i < 5; i++) { 2147 for (q = 0; q < buf_domains; q++) 2148 if (buf_recycle(&bdomain[q], true) != 0) 2149 done = true; 2150 if (done) 2151 break; 2152 } 2153 return; 2154 } 2155 2156 /* 2157 * Attempt to initiate asynchronous I/O on read-ahead blocks. We must 2158 * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set, 2159 * the buffer is valid and we do not have to do anything. 2160 */ 2161 static void 2162 breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt, 2163 struct ucred * cred, int flags, void (*ckhashfunc)(struct buf *)) 2164 { 2165 struct buf *rabp; 2166 struct thread *td; 2167 int i; 2168 2169 td = curthread; 2170 2171 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 2172 if (inmem(vp, *rablkno)) 2173 continue; 2174 rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0); 2175 if ((rabp->b_flags & B_CACHE) != 0) { 2176 brelse(rabp); 2177 continue; 2178 } 2179 #ifdef RACCT 2180 if (racct_enable) { 2181 PROC_LOCK(curproc); 2182 racct_add_buf(curproc, rabp, 0); 2183 PROC_UNLOCK(curproc); 2184 } 2185 #endif /* RACCT */ 2186 td->td_ru.ru_inblock++; 2187 rabp->b_flags |= B_ASYNC; 2188 rabp->b_flags &= ~B_INVAL; 2189 if ((flags & GB_CKHASH) != 0) { 2190 rabp->b_flags |= B_CKHASH; 2191 rabp->b_ckhashcalc = ckhashfunc; 2192 } 2193 rabp->b_ioflags &= ~BIO_ERROR; 2194 rabp->b_iocmd = BIO_READ; 2195 if (rabp->b_rcred == NOCRED && cred != NOCRED) 2196 rabp->b_rcred = crhold(cred); 2197 vfs_busy_pages(rabp, 0); 2198 BUF_KERNPROC(rabp); 2199 rabp->b_iooffset = dbtob(rabp->b_blkno); 2200 bstrategy(rabp); 2201 } 2202 } 2203 2204 /* 2205 * Entry point for bread() and breadn() via #defines in sys/buf.h. 2206 * 2207 * Get a buffer with the specified data. Look in the cache first. We 2208 * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE 2209 * is set, the buffer is valid and we do not have to do anything, see 2210 * getblk(). Also starts asynchronous I/O on read-ahead blocks. 2211 * 2212 * Always return a NULL buffer pointer (in bpp) when returning an error. 2213 * 2214 * The blkno parameter is the logical block being requested. Normally 2215 * the mapping of logical block number to disk block address is done 2216 * by calling VOP_BMAP(). However, if the mapping is already known, the 2217 * disk block address can be passed using the dblkno parameter. If the 2218 * disk block address is not known, then the same value should be passed 2219 * for blkno and dblkno. 2220 */ 2221 int 2222 breadn_flags(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, 2223 daddr_t *rablkno, int *rabsize, int cnt, struct ucred *cred, int flags, 2224 void (*ckhashfunc)(struct buf *), struct buf **bpp) 2225 { 2226 struct buf *bp; 2227 struct thread *td; 2228 int error, readwait, rv; 2229 2230 CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size); 2231 td = curthread; 2232 /* 2233 * Can only return NULL if GB_LOCK_NOWAIT or GB_SPARSE flags 2234 * are specified. 2235 */ 2236 error = getblkx(vp, blkno, dblkno, size, 0, 0, flags, &bp); 2237 if (error != 0) { 2238 *bpp = NULL; 2239 return (error); 2240 } 2241 KASSERT(blkno == bp->b_lblkno, 2242 ("getblkx returned buffer for blkno %jd instead of blkno %jd", 2243 (intmax_t)bp->b_lblkno, (intmax_t)blkno)); 2244 flags &= ~GB_NOSPARSE; 2245 *bpp = bp; 2246 2247 /* 2248 * If not found in cache, do some I/O 2249 */ 2250 readwait = 0; 2251 if ((bp->b_flags & B_CACHE) == 0) { 2252 #ifdef RACCT 2253 if (racct_enable) { 2254 PROC_LOCK(td->td_proc); 2255 racct_add_buf(td->td_proc, bp, 0); 2256 PROC_UNLOCK(td->td_proc); 2257 } 2258 #endif /* RACCT */ 2259 td->td_ru.ru_inblock++; 2260 bp->b_iocmd = BIO_READ; 2261 bp->b_flags &= ~B_INVAL; 2262 if ((flags & GB_CKHASH) != 0) { 2263 bp->b_flags |= B_CKHASH; 2264 bp->b_ckhashcalc = ckhashfunc; 2265 } 2266 if ((flags & GB_CVTENXIO) != 0) 2267 bp->b_xflags |= BX_CVTENXIO; 2268 bp->b_ioflags &= ~BIO_ERROR; 2269 if (bp->b_rcred == NOCRED && cred != NOCRED) 2270 bp->b_rcred = crhold(cred); 2271 vfs_busy_pages(bp, 0); 2272 bp->b_iooffset = dbtob(bp->b_blkno); 2273 bstrategy(bp); 2274 ++readwait; 2275 } 2276 2277 /* 2278 * Attempt to initiate asynchronous I/O on read-ahead blocks. 2279 */ 2280 breada(vp, rablkno, rabsize, cnt, cred, flags, ckhashfunc); 2281 2282 rv = 0; 2283 if (readwait) { 2284 rv = bufwait(bp); 2285 if (rv != 0) { 2286 brelse(bp); 2287 *bpp = NULL; 2288 } 2289 } 2290 return (rv); 2291 } 2292 2293 /* 2294 * Write, release buffer on completion. (Done by iodone 2295 * if async). Do not bother writing anything if the buffer 2296 * is invalid. 2297 * 2298 * Note that we set B_CACHE here, indicating that buffer is 2299 * fully valid and thus cacheable. This is true even of NFS 2300 * now so we set it generally. This could be set either here 2301 * or in biodone() since the I/O is synchronous. We put it 2302 * here. 2303 */ 2304 int 2305 bufwrite(struct buf *bp) 2306 { 2307 int oldflags; 2308 struct vnode *vp; 2309 long space; 2310 int vp_md; 2311 2312 CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2313 if ((bp->b_bufobj->bo_flag & BO_DEAD) != 0) { 2314 bp->b_flags |= B_INVAL | B_RELBUF; 2315 bp->b_flags &= ~B_CACHE; 2316 brelse(bp); 2317 return (ENXIO); 2318 } 2319 if (bp->b_flags & B_INVAL) { 2320 brelse(bp); 2321 return (0); 2322 } 2323 2324 if (bp->b_flags & B_BARRIER) 2325 atomic_add_long(&barrierwrites, 1); 2326 2327 oldflags = bp->b_flags; 2328 2329 KASSERT(!(bp->b_vflags & BV_BKGRDINPROG), 2330 ("FFS background buffer should not get here %p", bp)); 2331 2332 vp = bp->b_vp; 2333 if (vp) 2334 vp_md = vp->v_vflag & VV_MD; 2335 else 2336 vp_md = 0; 2337 2338 /* 2339 * Mark the buffer clean. Increment the bufobj write count 2340 * before bundirty() call, to prevent other thread from seeing 2341 * empty dirty list and zero counter for writes in progress, 2342 * falsely indicating that the bufobj is clean. 2343 */ 2344 bufobj_wref(bp->b_bufobj); 2345 bundirty(bp); 2346 2347 bp->b_flags &= ~B_DONE; 2348 bp->b_ioflags &= ~BIO_ERROR; 2349 bp->b_flags |= B_CACHE; 2350 bp->b_iocmd = BIO_WRITE; 2351 2352 vfs_busy_pages(bp, 1); 2353 2354 /* 2355 * Normal bwrites pipeline writes 2356 */ 2357 bp->b_runningbufspace = bp->b_bufsize; 2358 space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace); 2359 2360 #ifdef RACCT 2361 if (racct_enable) { 2362 PROC_LOCK(curproc); 2363 racct_add_buf(curproc, bp, 1); 2364 PROC_UNLOCK(curproc); 2365 } 2366 #endif /* RACCT */ 2367 curthread->td_ru.ru_oublock++; 2368 if (oldflags & B_ASYNC) 2369 BUF_KERNPROC(bp); 2370 bp->b_iooffset = dbtob(bp->b_blkno); 2371 buf_track(bp, __func__); 2372 bstrategy(bp); 2373 2374 if ((oldflags & B_ASYNC) == 0) { 2375 int rtval = bufwait(bp); 2376 brelse(bp); 2377 return (rtval); 2378 } else if (space > hirunningspace) { 2379 /* 2380 * don't allow the async write to saturate the I/O 2381 * system. We will not deadlock here because 2382 * we are blocking waiting for I/O that is already in-progress 2383 * to complete. We do not block here if it is the update 2384 * or syncer daemon trying to clean up as that can lead 2385 * to deadlock. 2386 */ 2387 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md) 2388 waitrunningbufspace(); 2389 } 2390 2391 return (0); 2392 } 2393 2394 void 2395 bufbdflush(struct bufobj *bo, struct buf *bp) 2396 { 2397 struct buf *nbp; 2398 struct bufdomain *bd; 2399 2400 bd = &bdomain[bo->bo_domain]; 2401 if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh + 10) { 2402 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); 2403 altbufferflushes++; 2404 } else if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh) { 2405 BO_LOCK(bo); 2406 /* 2407 * Try to find a buffer to flush. 2408 */ 2409 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2410 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2411 BUF_LOCK(nbp, 2412 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2413 continue; 2414 if (bp == nbp) 2415 panic("bdwrite: found ourselves"); 2416 BO_UNLOCK(bo); 2417 /* Don't countdeps with the bo lock held. */ 2418 if (buf_countdeps(nbp, 0)) { 2419 BO_LOCK(bo); 2420 BUF_UNLOCK(nbp); 2421 continue; 2422 } 2423 if (nbp->b_flags & B_CLUSTEROK) { 2424 vfs_bio_awrite(nbp); 2425 } else { 2426 bremfree(nbp); 2427 bawrite(nbp); 2428 } 2429 dirtybufferflushes++; 2430 break; 2431 } 2432 if (nbp == NULL) 2433 BO_UNLOCK(bo); 2434 } 2435 } 2436 2437 /* 2438 * Delayed write. (Buffer is marked dirty). Do not bother writing 2439 * anything if the buffer is marked invalid. 2440 * 2441 * Note that since the buffer must be completely valid, we can safely 2442 * set B_CACHE. In fact, we have to set B_CACHE here rather then in 2443 * biodone() in order to prevent getblk from writing the buffer 2444 * out synchronously. 2445 */ 2446 void 2447 bdwrite(struct buf *bp) 2448 { 2449 struct thread *td = curthread; 2450 struct vnode *vp; 2451 struct bufobj *bo; 2452 2453 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2454 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2455 KASSERT((bp->b_flags & B_BARRIER) == 0, 2456 ("Barrier request in delayed write %p", bp)); 2457 2458 if (bp->b_flags & B_INVAL) { 2459 brelse(bp); 2460 return; 2461 } 2462 2463 /* 2464 * If we have too many dirty buffers, don't create any more. 2465 * If we are wildly over our limit, then force a complete 2466 * cleanup. Otherwise, just keep the situation from getting 2467 * out of control. Note that we have to avoid a recursive 2468 * disaster and not try to clean up after our own cleanup! 2469 */ 2470 vp = bp->b_vp; 2471 bo = bp->b_bufobj; 2472 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) { 2473 td->td_pflags |= TDP_INBDFLUSH; 2474 BO_BDFLUSH(bo, bp); 2475 td->td_pflags &= ~TDP_INBDFLUSH; 2476 } else 2477 recursiveflushes++; 2478 2479 bdirty(bp); 2480 /* 2481 * Set B_CACHE, indicating that the buffer is fully valid. This is 2482 * true even of NFS now. 2483 */ 2484 bp->b_flags |= B_CACHE; 2485 2486 /* 2487 * This bmap keeps the system from needing to do the bmap later, 2488 * perhaps when the system is attempting to do a sync. Since it 2489 * is likely that the indirect block -- or whatever other datastructure 2490 * that the filesystem needs is still in memory now, it is a good 2491 * thing to do this. Note also, that if the pageout daemon is 2492 * requesting a sync -- there might not be enough memory to do 2493 * the bmap then... So, this is important to do. 2494 */ 2495 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) { 2496 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 2497 } 2498 2499 buf_track(bp, __func__); 2500 2501 /* 2502 * Set the *dirty* buffer range based upon the VM system dirty 2503 * pages. 2504 * 2505 * Mark the buffer pages as clean. We need to do this here to 2506 * satisfy the vnode_pager and the pageout daemon, so that it 2507 * thinks that the pages have been "cleaned". Note that since 2508 * the pages are in a delayed write buffer -- the VFS layer 2509 * "will" see that the pages get written out on the next sync, 2510 * or perhaps the cluster will be completed. 2511 */ 2512 vfs_clean_pages_dirty_buf(bp); 2513 bqrelse(bp); 2514 2515 /* 2516 * note: we cannot initiate I/O from a bdwrite even if we wanted to, 2517 * due to the softdep code. 2518 */ 2519 } 2520 2521 /* 2522 * bdirty: 2523 * 2524 * Turn buffer into delayed write request. We must clear BIO_READ and 2525 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to 2526 * itself to properly update it in the dirty/clean lists. We mark it 2527 * B_DONE to ensure that any asynchronization of the buffer properly 2528 * clears B_DONE ( else a panic will occur later ). 2529 * 2530 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which 2531 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty() 2532 * should only be called if the buffer is known-good. 2533 * 2534 * Since the buffer is not on a queue, we do not update the numfreebuffers 2535 * count. 2536 * 2537 * The buffer must be on QUEUE_NONE. 2538 */ 2539 void 2540 bdirty(struct buf *bp) 2541 { 2542 2543 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X", 2544 bp, bp->b_vp, bp->b_flags); 2545 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2546 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2547 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2548 bp->b_flags &= ~(B_RELBUF); 2549 bp->b_iocmd = BIO_WRITE; 2550 2551 if ((bp->b_flags & B_DELWRI) == 0) { 2552 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI; 2553 reassignbuf(bp); 2554 bdirtyadd(bp); 2555 } 2556 } 2557 2558 /* 2559 * bundirty: 2560 * 2561 * Clear B_DELWRI for buffer. 2562 * 2563 * Since the buffer is not on a queue, we do not update the numfreebuffers 2564 * count. 2565 * 2566 * The buffer must be on QUEUE_NONE. 2567 */ 2568 2569 void 2570 bundirty(struct buf *bp) 2571 { 2572 2573 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2574 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2575 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2576 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2577 2578 if (bp->b_flags & B_DELWRI) { 2579 bp->b_flags &= ~B_DELWRI; 2580 reassignbuf(bp); 2581 bdirtysub(bp); 2582 } 2583 /* 2584 * Since it is now being written, we can clear its deferred write flag. 2585 */ 2586 bp->b_flags &= ~B_DEFERRED; 2587 } 2588 2589 /* 2590 * bawrite: 2591 * 2592 * Asynchronous write. Start output on a buffer, but do not wait for 2593 * it to complete. The buffer is released when the output completes. 2594 * 2595 * bwrite() ( or the VOP routine anyway ) is responsible for handling 2596 * B_INVAL buffers. Not us. 2597 */ 2598 void 2599 bawrite(struct buf *bp) 2600 { 2601 2602 bp->b_flags |= B_ASYNC; 2603 (void) bwrite(bp); 2604 } 2605 2606 /* 2607 * babarrierwrite: 2608 * 2609 * Asynchronous barrier write. Start output on a buffer, but do not 2610 * wait for it to complete. Place a write barrier after this write so 2611 * that this buffer and all buffers written before it are committed to 2612 * the disk before any buffers written after this write are committed 2613 * to the disk. The buffer is released when the output completes. 2614 */ 2615 void 2616 babarrierwrite(struct buf *bp) 2617 { 2618 2619 bp->b_flags |= B_ASYNC | B_BARRIER; 2620 (void) bwrite(bp); 2621 } 2622 2623 /* 2624 * bbarrierwrite: 2625 * 2626 * Synchronous barrier write. Start output on a buffer and wait for 2627 * it to complete. Place a write barrier after this write so that 2628 * this buffer and all buffers written before it are committed to 2629 * the disk before any buffers written after this write are committed 2630 * to the disk. The buffer is released when the output completes. 2631 */ 2632 int 2633 bbarrierwrite(struct buf *bp) 2634 { 2635 2636 bp->b_flags |= B_BARRIER; 2637 return (bwrite(bp)); 2638 } 2639 2640 /* 2641 * bwillwrite: 2642 * 2643 * Called prior to the locking of any vnodes when we are expecting to 2644 * write. We do not want to starve the buffer cache with too many 2645 * dirty buffers so we block here. By blocking prior to the locking 2646 * of any vnodes we attempt to avoid the situation where a locked vnode 2647 * prevents the various system daemons from flushing related buffers. 2648 */ 2649 void 2650 bwillwrite(void) 2651 { 2652 2653 if (buf_dirty_count_severe()) { 2654 mtx_lock(&bdirtylock); 2655 while (buf_dirty_count_severe()) { 2656 bdirtywait = 1; 2657 msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4), 2658 "flswai", 0); 2659 } 2660 mtx_unlock(&bdirtylock); 2661 } 2662 } 2663 2664 /* 2665 * Return true if we have too many dirty buffers. 2666 */ 2667 int 2668 buf_dirty_count_severe(void) 2669 { 2670 2671 return (!BIT_EMPTY(BUF_DOMAINS, &bdhidirty)); 2672 } 2673 2674 /* 2675 * brelse: 2676 * 2677 * Release a busy buffer and, if requested, free its resources. The 2678 * buffer will be stashed in the appropriate bufqueue[] allowing it 2679 * to be accessed later as a cache entity or reused for other purposes. 2680 */ 2681 void 2682 brelse(struct buf *bp) 2683 { 2684 struct mount *v_mnt; 2685 int qindex; 2686 2687 /* 2688 * Many functions erroneously call brelse with a NULL bp under rare 2689 * error conditions. Simply return when called with a NULL bp. 2690 */ 2691 if (bp == NULL) 2692 return; 2693 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X", 2694 bp, bp->b_vp, bp->b_flags); 2695 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2696 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2697 KASSERT((bp->b_flags & B_VMIO) != 0 || (bp->b_flags & B_NOREUSE) == 0, 2698 ("brelse: non-VMIO buffer marked NOREUSE")); 2699 2700 if (BUF_LOCKRECURSED(bp)) { 2701 /* 2702 * Do not process, in particular, do not handle the 2703 * B_INVAL/B_RELBUF and do not release to free list. 2704 */ 2705 BUF_UNLOCK(bp); 2706 return; 2707 } 2708 2709 if (bp->b_flags & B_MANAGED) { 2710 bqrelse(bp); 2711 return; 2712 } 2713 2714 if (LIST_EMPTY(&bp->b_dep)) { 2715 bp->b_flags &= ~B_IOSTARTED; 2716 } else { 2717 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2718 ("brelse: SU io not finished bp %p", bp)); 2719 } 2720 2721 if ((bp->b_vflags & (BV_BKGRDINPROG | BV_BKGRDERR)) == BV_BKGRDERR) { 2722 BO_LOCK(bp->b_bufobj); 2723 bp->b_vflags &= ~BV_BKGRDERR; 2724 BO_UNLOCK(bp->b_bufobj); 2725 bdirty(bp); 2726 } 2727 2728 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2729 (bp->b_flags & B_INVALONERR)) { 2730 /* 2731 * Forced invalidation of dirty buffer contents, to be used 2732 * after a failed write in the rare case that the loss of the 2733 * contents is acceptable. The buffer is invalidated and 2734 * freed. 2735 */ 2736 bp->b_flags |= B_INVAL | B_RELBUF | B_NOCACHE; 2737 bp->b_flags &= ~(B_ASYNC | B_CACHE); 2738 } 2739 2740 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2741 (bp->b_error != ENXIO || !LIST_EMPTY(&bp->b_dep)) && 2742 !(bp->b_flags & B_INVAL)) { 2743 /* 2744 * Failed write, redirty. All errors except ENXIO (which 2745 * means the device is gone) are treated as being 2746 * transient. 2747 * 2748 * XXX Treating EIO as transient is not correct; the 2749 * contract with the local storage device drivers is that 2750 * they will only return EIO once the I/O is no longer 2751 * retriable. Network I/O also respects this through the 2752 * guarantees of TCP and/or the internal retries of NFS. 2753 * ENOMEM might be transient, but we also have no way of 2754 * knowing when its ok to retry/reschedule. In general, 2755 * this entire case should be made obsolete through better 2756 * error handling/recovery and resource scheduling. 2757 * 2758 * Do this also for buffers that failed with ENXIO, but have 2759 * non-empty dependencies - the soft updates code might need 2760 * to access the buffer to untangle them. 2761 * 2762 * Must clear BIO_ERROR to prevent pages from being scrapped. 2763 */ 2764 bp->b_ioflags &= ~BIO_ERROR; 2765 bdirty(bp); 2766 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) || 2767 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) { 2768 /* 2769 * Either a failed read I/O, or we were asked to free or not 2770 * cache the buffer, or we failed to write to a device that's 2771 * no longer present. 2772 */ 2773 bp->b_flags |= B_INVAL; 2774 if (!LIST_EMPTY(&bp->b_dep)) 2775 buf_deallocate(bp); 2776 if (bp->b_flags & B_DELWRI) 2777 bdirtysub(bp); 2778 bp->b_flags &= ~(B_DELWRI | B_CACHE); 2779 if ((bp->b_flags & B_VMIO) == 0) { 2780 allocbuf(bp, 0); 2781 if (bp->b_vp) 2782 brelvp(bp); 2783 } 2784 } 2785 2786 /* 2787 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_truncate() 2788 * is called with B_DELWRI set, the underlying pages may wind up 2789 * getting freed causing a previous write (bdwrite()) to get 'lost' 2790 * because pages associated with a B_DELWRI bp are marked clean. 2791 * 2792 * We still allow the B_INVAL case to call vfs_vmio_truncate(), even 2793 * if B_DELWRI is set. 2794 */ 2795 if (bp->b_flags & B_DELWRI) 2796 bp->b_flags &= ~B_RELBUF; 2797 2798 /* 2799 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 2800 * constituted, not even NFS buffers now. Two flags effect this. If 2801 * B_INVAL, the struct buf is invalidated but the VM object is kept 2802 * around ( i.e. so it is trivial to reconstitute the buffer later ). 2803 * 2804 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be 2805 * invalidated. BIO_ERROR cannot be set for a failed write unless the 2806 * buffer is also B_INVAL because it hits the re-dirtying code above. 2807 * 2808 * Normally we can do this whether a buffer is B_DELWRI or not. If 2809 * the buffer is an NFS buffer, it is tracking piecemeal writes or 2810 * the commit state and we cannot afford to lose the buffer. If the 2811 * buffer has a background write in progress, we need to keep it 2812 * around to prevent it from being reconstituted and starting a second 2813 * background write. 2814 */ 2815 2816 v_mnt = bp->b_vp != NULL ? bp->b_vp->v_mount : NULL; 2817 2818 if ((bp->b_flags & B_VMIO) && (bp->b_flags & B_NOCACHE || 2819 (bp->b_ioflags & BIO_ERROR && bp->b_iocmd == BIO_READ)) && 2820 (v_mnt == NULL || (v_mnt->mnt_vfc->vfc_flags & VFCF_NETWORK) == 0 || 2821 vn_isdisk(bp->b_vp) || (bp->b_flags & B_DELWRI) == 0)) { 2822 vfs_vmio_invalidate(bp); 2823 allocbuf(bp, 0); 2824 } 2825 2826 if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0 || 2827 (bp->b_flags & (B_DELWRI | B_NOREUSE)) == B_NOREUSE) { 2828 allocbuf(bp, 0); 2829 bp->b_flags &= ~B_NOREUSE; 2830 if (bp->b_vp != NULL) 2831 brelvp(bp); 2832 } 2833 2834 /* 2835 * If the buffer has junk contents signal it and eventually 2836 * clean up B_DELWRI and diassociate the vnode so that gbincore() 2837 * doesn't find it. 2838 */ 2839 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 || 2840 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0) 2841 bp->b_flags |= B_INVAL; 2842 if (bp->b_flags & B_INVAL) { 2843 if (bp->b_flags & B_DELWRI) 2844 bundirty(bp); 2845 if (bp->b_vp) 2846 brelvp(bp); 2847 } 2848 2849 buf_track(bp, __func__); 2850 2851 /* buffers with no memory */ 2852 if (bp->b_bufsize == 0) { 2853 buf_free(bp); 2854 return; 2855 } 2856 /* buffers with junk contents */ 2857 if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) || 2858 (bp->b_ioflags & BIO_ERROR)) { 2859 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 2860 if (bp->b_vflags & BV_BKGRDINPROG) 2861 panic("losing buffer 2"); 2862 qindex = QUEUE_CLEAN; 2863 bp->b_flags |= B_AGE; 2864 /* remaining buffers */ 2865 } else if (bp->b_flags & B_DELWRI) 2866 qindex = QUEUE_DIRTY; 2867 else 2868 qindex = QUEUE_CLEAN; 2869 2870 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) 2871 panic("brelse: not dirty"); 2872 2873 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_RELBUF | B_DIRECT); 2874 bp->b_xflags &= ~(BX_CVTENXIO); 2875 /* binsfree unlocks bp. */ 2876 binsfree(bp, qindex); 2877 } 2878 2879 /* 2880 * Release a buffer back to the appropriate queue but do not try to free 2881 * it. The buffer is expected to be used again soon. 2882 * 2883 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by 2884 * biodone() to requeue an async I/O on completion. It is also used when 2885 * known good buffers need to be requeued but we think we may need the data 2886 * again soon. 2887 * 2888 * XXX we should be able to leave the B_RELBUF hint set on completion. 2889 */ 2890 void 2891 bqrelse(struct buf *bp) 2892 { 2893 int qindex; 2894 2895 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2896 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2897 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2898 2899 qindex = QUEUE_NONE; 2900 if (BUF_LOCKRECURSED(bp)) { 2901 /* do not release to free list */ 2902 BUF_UNLOCK(bp); 2903 return; 2904 } 2905 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 2906 bp->b_xflags &= ~(BX_CVTENXIO); 2907 2908 if (LIST_EMPTY(&bp->b_dep)) { 2909 bp->b_flags &= ~B_IOSTARTED; 2910 } else { 2911 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2912 ("bqrelse: SU io not finished bp %p", bp)); 2913 } 2914 2915 if (bp->b_flags & B_MANAGED) { 2916 if (bp->b_flags & B_REMFREE) 2917 bremfreef(bp); 2918 goto out; 2919 } 2920 2921 /* buffers with stale but valid contents */ 2922 if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG | 2923 BV_BKGRDERR)) == BV_BKGRDERR) { 2924 BO_LOCK(bp->b_bufobj); 2925 bp->b_vflags &= ~BV_BKGRDERR; 2926 BO_UNLOCK(bp->b_bufobj); 2927 qindex = QUEUE_DIRTY; 2928 } else { 2929 if ((bp->b_flags & B_DELWRI) == 0 && 2930 (bp->b_xflags & BX_VNDIRTY)) 2931 panic("bqrelse: not dirty"); 2932 if ((bp->b_flags & B_NOREUSE) != 0) { 2933 brelse(bp); 2934 return; 2935 } 2936 qindex = QUEUE_CLEAN; 2937 } 2938 buf_track(bp, __func__); 2939 /* binsfree unlocks bp. */ 2940 binsfree(bp, qindex); 2941 return; 2942 2943 out: 2944 buf_track(bp, __func__); 2945 /* unlock */ 2946 BUF_UNLOCK(bp); 2947 } 2948 2949 /* 2950 * Complete I/O to a VMIO backed page. Validate the pages as appropriate, 2951 * restore bogus pages. 2952 */ 2953 static void 2954 vfs_vmio_iodone(struct buf *bp) 2955 { 2956 vm_ooffset_t foff; 2957 vm_page_t m; 2958 vm_object_t obj; 2959 struct vnode *vp __unused; 2960 int i, iosize, resid; 2961 bool bogus; 2962 2963 obj = bp->b_bufobj->bo_object; 2964 KASSERT(blockcount_read(&obj->paging_in_progress) >= bp->b_npages, 2965 ("vfs_vmio_iodone: paging in progress(%d) < b_npages(%d)", 2966 blockcount_read(&obj->paging_in_progress), bp->b_npages)); 2967 2968 vp = bp->b_vp; 2969 VNPASS(vp->v_holdcnt > 0, vp); 2970 VNPASS(vp->v_object != NULL, vp); 2971 2972 foff = bp->b_offset; 2973 KASSERT(bp->b_offset != NOOFFSET, 2974 ("vfs_vmio_iodone: bp %p has no buffer offset", bp)); 2975 2976 bogus = false; 2977 iosize = bp->b_bcount - bp->b_resid; 2978 for (i = 0; i < bp->b_npages; i++) { 2979 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff; 2980 if (resid > iosize) 2981 resid = iosize; 2982 2983 /* 2984 * cleanup bogus pages, restoring the originals 2985 */ 2986 m = bp->b_pages[i]; 2987 if (m == bogus_page) { 2988 bogus = true; 2989 m = vm_page_relookup(obj, OFF_TO_IDX(foff)); 2990 if (m == NULL) 2991 panic("biodone: page disappeared!"); 2992 bp->b_pages[i] = m; 2993 } else if ((bp->b_iocmd == BIO_READ) && resid > 0) { 2994 /* 2995 * In the write case, the valid and clean bits are 2996 * already changed correctly ( see bdwrite() ), so we 2997 * only need to do this here in the read case. 2998 */ 2999 KASSERT((m->dirty & vm_page_bits(foff & PAGE_MASK, 3000 resid)) == 0, ("vfs_vmio_iodone: page %p " 3001 "has unexpected dirty bits", m)); 3002 vfs_page_set_valid(bp, foff, m); 3003 } 3004 KASSERT(OFF_TO_IDX(foff) == m->pindex, 3005 ("vfs_vmio_iodone: foff(%jd)/pindex(%ju) mismatch", 3006 (intmax_t)foff, (uintmax_t)m->pindex)); 3007 3008 vm_page_sunbusy(m); 3009 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3010 iosize -= resid; 3011 } 3012 vm_object_pip_wakeupn(obj, bp->b_npages); 3013 if (bogus && buf_mapped(bp)) { 3014 BUF_CHECK_MAPPED(bp); 3015 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 3016 bp->b_pages, bp->b_npages); 3017 } 3018 } 3019 3020 /* 3021 * Perform page invalidation when a buffer is released. The fully invalid 3022 * pages will be reclaimed later in vfs_vmio_truncate(). 3023 */ 3024 static void 3025 vfs_vmio_invalidate(struct buf *bp) 3026 { 3027 vm_object_t obj; 3028 vm_page_t m; 3029 int flags, i, resid, poffset, presid; 3030 3031 if (buf_mapped(bp)) { 3032 BUF_CHECK_MAPPED(bp); 3033 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages); 3034 } else 3035 BUF_CHECK_UNMAPPED(bp); 3036 /* 3037 * Get the base offset and length of the buffer. Note that 3038 * in the VMIO case if the buffer block size is not 3039 * page-aligned then b_data pointer may not be page-aligned. 3040 * But our b_pages[] array *IS* page aligned. 3041 * 3042 * block sizes less then DEV_BSIZE (usually 512) are not 3043 * supported due to the page granularity bits (m->valid, 3044 * m->dirty, etc...). 3045 * 3046 * See man buf(9) for more information 3047 */ 3048 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3049 obj = bp->b_bufobj->bo_object; 3050 resid = bp->b_bufsize; 3051 poffset = bp->b_offset & PAGE_MASK; 3052 VM_OBJECT_WLOCK(obj); 3053 for (i = 0; i < bp->b_npages; i++) { 3054 m = bp->b_pages[i]; 3055 if (m == bogus_page) 3056 panic("vfs_vmio_invalidate: Unexpected bogus page."); 3057 bp->b_pages[i] = NULL; 3058 3059 presid = resid > (PAGE_SIZE - poffset) ? 3060 (PAGE_SIZE - poffset) : resid; 3061 KASSERT(presid >= 0, ("brelse: extra page")); 3062 vm_page_busy_acquire(m, VM_ALLOC_SBUSY); 3063 if (pmap_page_wired_mappings(m) == 0) 3064 vm_page_set_invalid(m, poffset, presid); 3065 vm_page_sunbusy(m); 3066 vm_page_release_locked(m, flags); 3067 resid -= presid; 3068 poffset = 0; 3069 } 3070 VM_OBJECT_WUNLOCK(obj); 3071 bp->b_npages = 0; 3072 } 3073 3074 /* 3075 * Page-granular truncation of an existing VMIO buffer. 3076 */ 3077 static void 3078 vfs_vmio_truncate(struct buf *bp, int desiredpages) 3079 { 3080 vm_object_t obj; 3081 vm_page_t m; 3082 int flags, i; 3083 3084 if (bp->b_npages == desiredpages) 3085 return; 3086 3087 if (buf_mapped(bp)) { 3088 BUF_CHECK_MAPPED(bp); 3089 pmap_qremove((vm_offset_t)trunc_page((vm_offset_t)bp->b_data) + 3090 (desiredpages << PAGE_SHIFT), bp->b_npages - desiredpages); 3091 } else 3092 BUF_CHECK_UNMAPPED(bp); 3093 3094 /* 3095 * The object lock is needed only if we will attempt to free pages. 3096 */ 3097 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3098 if ((bp->b_flags & B_DIRECT) != 0) { 3099 flags |= VPR_TRYFREE; 3100 obj = bp->b_bufobj->bo_object; 3101 VM_OBJECT_WLOCK(obj); 3102 } else { 3103 obj = NULL; 3104 } 3105 for (i = desiredpages; i < bp->b_npages; i++) { 3106 m = bp->b_pages[i]; 3107 KASSERT(m != bogus_page, ("allocbuf: bogus page found")); 3108 bp->b_pages[i] = NULL; 3109 if (obj != NULL) 3110 vm_page_release_locked(m, flags); 3111 else 3112 vm_page_release(m, flags); 3113 } 3114 if (obj != NULL) 3115 VM_OBJECT_WUNLOCK(obj); 3116 bp->b_npages = desiredpages; 3117 } 3118 3119 /* 3120 * Byte granular extension of VMIO buffers. 3121 */ 3122 static void 3123 vfs_vmio_extend(struct buf *bp, int desiredpages, int size) 3124 { 3125 /* 3126 * We are growing the buffer, possibly in a 3127 * byte-granular fashion. 3128 */ 3129 vm_object_t obj; 3130 vm_offset_t toff; 3131 vm_offset_t tinc; 3132 vm_page_t m; 3133 3134 /* 3135 * Step 1, bring in the VM pages from the object, allocating 3136 * them if necessary. We must clear B_CACHE if these pages 3137 * are not valid for the range covered by the buffer. 3138 */ 3139 obj = bp->b_bufobj->bo_object; 3140 if (bp->b_npages < desiredpages) { 3141 KASSERT(desiredpages <= atop(maxbcachebuf), 3142 ("vfs_vmio_extend past maxbcachebuf %p %d %u", 3143 bp, desiredpages, maxbcachebuf)); 3144 3145 /* 3146 * We must allocate system pages since blocking 3147 * here could interfere with paging I/O, no 3148 * matter which process we are. 3149 * 3150 * Only exclusive busy can be tested here. 3151 * Blocking on shared busy might lead to 3152 * deadlocks once allocbuf() is called after 3153 * pages are vfs_busy_pages(). 3154 */ 3155 (void)vm_page_grab_pages_unlocked(obj, 3156 OFF_TO_IDX(bp->b_offset) + bp->b_npages, 3157 VM_ALLOC_SYSTEM | VM_ALLOC_IGN_SBUSY | 3158 VM_ALLOC_NOBUSY | VM_ALLOC_WIRED, 3159 &bp->b_pages[bp->b_npages], desiredpages - bp->b_npages); 3160 bp->b_npages = desiredpages; 3161 } 3162 3163 /* 3164 * Step 2. We've loaded the pages into the buffer, 3165 * we have to figure out if we can still have B_CACHE 3166 * set. Note that B_CACHE is set according to the 3167 * byte-granular range ( bcount and size ), not the 3168 * aligned range ( newbsize ). 3169 * 3170 * The VM test is against m->valid, which is DEV_BSIZE 3171 * aligned. Needless to say, the validity of the data 3172 * needs to also be DEV_BSIZE aligned. Note that this 3173 * fails with NFS if the server or some other client 3174 * extends the file's EOF. If our buffer is resized, 3175 * B_CACHE may remain set! XXX 3176 */ 3177 toff = bp->b_bcount; 3178 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK); 3179 while ((bp->b_flags & B_CACHE) && toff < size) { 3180 vm_pindex_t pi; 3181 3182 if (tinc > (size - toff)) 3183 tinc = size - toff; 3184 pi = ((bp->b_offset & PAGE_MASK) + toff) >> PAGE_SHIFT; 3185 m = bp->b_pages[pi]; 3186 vfs_buf_test_cache(bp, bp->b_offset, toff, tinc, m); 3187 toff += tinc; 3188 tinc = PAGE_SIZE; 3189 } 3190 3191 /* 3192 * Step 3, fixup the KVA pmap. 3193 */ 3194 if (buf_mapped(bp)) 3195 bpmap_qenter(bp); 3196 else 3197 BUF_CHECK_UNMAPPED(bp); 3198 } 3199 3200 /* 3201 * Check to see if a block at a particular lbn is available for a clustered 3202 * write. 3203 */ 3204 static int 3205 vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno) 3206 { 3207 struct buf *bpa; 3208 int match; 3209 3210 match = 0; 3211 3212 /* If the buf isn't in core skip it */ 3213 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL) 3214 return (0); 3215 3216 /* If the buf is busy we don't want to wait for it */ 3217 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 3218 return (0); 3219 3220 /* Only cluster with valid clusterable delayed write buffers */ 3221 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) != 3222 (B_DELWRI | B_CLUSTEROK)) 3223 goto done; 3224 3225 if (bpa->b_bufsize != size) 3226 goto done; 3227 3228 /* 3229 * Check to see if it is in the expected place on disk and that the 3230 * block has been mapped. 3231 */ 3232 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno)) 3233 match = 1; 3234 done: 3235 BUF_UNLOCK(bpa); 3236 return (match); 3237 } 3238 3239 /* 3240 * vfs_bio_awrite: 3241 * 3242 * Implement clustered async writes for clearing out B_DELWRI buffers. 3243 * This is much better then the old way of writing only one buffer at 3244 * a time. Note that we may not be presented with the buffers in the 3245 * correct order, so we search for the cluster in both directions. 3246 */ 3247 int 3248 vfs_bio_awrite(struct buf *bp) 3249 { 3250 struct bufobj *bo; 3251 int i; 3252 int j; 3253 daddr_t lblkno = bp->b_lblkno; 3254 struct vnode *vp = bp->b_vp; 3255 int ncl; 3256 int nwritten; 3257 int size; 3258 int maxcl; 3259 int gbflags; 3260 3261 bo = &vp->v_bufobj; 3262 gbflags = (bp->b_data == unmapped_buf) ? GB_UNMAPPED : 0; 3263 /* 3264 * right now we support clustered writing only to regular files. If 3265 * we find a clusterable block we could be in the middle of a cluster 3266 * rather then at the beginning. 3267 */ 3268 if ((vp->v_type == VREG) && 3269 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 3270 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 3271 size = vp->v_mount->mnt_stat.f_iosize; 3272 maxcl = maxphys / size; 3273 3274 BO_RLOCK(bo); 3275 for (i = 1; i < maxcl; i++) 3276 if (vfs_bio_clcheck(vp, size, lblkno + i, 3277 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0) 3278 break; 3279 3280 for (j = 1; i + j <= maxcl && j <= lblkno; j++) 3281 if (vfs_bio_clcheck(vp, size, lblkno - j, 3282 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0) 3283 break; 3284 BO_RUNLOCK(bo); 3285 --j; 3286 ncl = i + j; 3287 /* 3288 * this is a possible cluster write 3289 */ 3290 if (ncl != 1) { 3291 BUF_UNLOCK(bp); 3292 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, 3293 gbflags); 3294 return (nwritten); 3295 } 3296 } 3297 bremfree(bp); 3298 bp->b_flags |= B_ASYNC; 3299 /* 3300 * default (old) behavior, writing out only one block 3301 * 3302 * XXX returns b_bufsize instead of b_bcount for nwritten? 3303 */ 3304 nwritten = bp->b_bufsize; 3305 (void) bwrite(bp); 3306 3307 return (nwritten); 3308 } 3309 3310 /* 3311 * getnewbuf_kva: 3312 * 3313 * Allocate KVA for an empty buf header according to gbflags. 3314 */ 3315 static int 3316 getnewbuf_kva(struct buf *bp, int gbflags, int maxsize) 3317 { 3318 3319 if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_UNMAPPED) { 3320 /* 3321 * In order to keep fragmentation sane we only allocate kva 3322 * in BKVASIZE chunks. XXX with vmem we can do page size. 3323 */ 3324 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK; 3325 3326 if (maxsize != bp->b_kvasize && 3327 bufkva_alloc(bp, maxsize, gbflags)) 3328 return (ENOSPC); 3329 } 3330 return (0); 3331 } 3332 3333 /* 3334 * getnewbuf: 3335 * 3336 * Find and initialize a new buffer header, freeing up existing buffers 3337 * in the bufqueues as necessary. The new buffer is returned locked. 3338 * 3339 * We block if: 3340 * We have insufficient buffer headers 3341 * We have insufficient buffer space 3342 * buffer_arena is too fragmented ( space reservation fails ) 3343 * If we have to flush dirty buffers ( but we try to avoid this ) 3344 * 3345 * The caller is responsible for releasing the reserved bufspace after 3346 * allocbuf() is called. 3347 */ 3348 static struct buf * 3349 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int maxsize, int gbflags) 3350 { 3351 struct bufdomain *bd; 3352 struct buf *bp; 3353 bool metadata, reserved; 3354 3355 bp = NULL; 3356 KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3357 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3358 if (!unmapped_buf_allowed) 3359 gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3360 3361 if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 || 3362 vp->v_type == VCHR) 3363 metadata = true; 3364 else 3365 metadata = false; 3366 if (vp == NULL) 3367 bd = &bdomain[0]; 3368 else 3369 bd = &bdomain[vp->v_bufobj.bo_domain]; 3370 3371 counter_u64_add(getnewbufcalls, 1); 3372 reserved = false; 3373 do { 3374 if (reserved == false && 3375 bufspace_reserve(bd, maxsize, metadata) != 0) { 3376 counter_u64_add(getnewbufrestarts, 1); 3377 continue; 3378 } 3379 reserved = true; 3380 if ((bp = buf_alloc(bd)) == NULL) { 3381 counter_u64_add(getnewbufrestarts, 1); 3382 continue; 3383 } 3384 if (getnewbuf_kva(bp, gbflags, maxsize) == 0) 3385 return (bp); 3386 break; 3387 } while (buf_recycle(bd, false) == 0); 3388 3389 if (reserved) 3390 bufspace_release(bd, maxsize); 3391 if (bp != NULL) { 3392 bp->b_flags |= B_INVAL; 3393 brelse(bp); 3394 } 3395 bufspace_wait(bd, vp, gbflags, slpflag, slptimeo); 3396 3397 return (NULL); 3398 } 3399 3400 /* 3401 * buf_daemon: 3402 * 3403 * buffer flushing daemon. Buffers are normally flushed by the 3404 * update daemon but if it cannot keep up this process starts to 3405 * take the load in an attempt to prevent getnewbuf() from blocking. 3406 */ 3407 static struct kproc_desc buf_kp = { 3408 "bufdaemon", 3409 buf_daemon, 3410 &bufdaemonproc 3411 }; 3412 SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp); 3413 3414 static int 3415 buf_flush(struct vnode *vp, struct bufdomain *bd, int target) 3416 { 3417 int flushed; 3418 3419 flushed = flushbufqueues(vp, bd, target, 0); 3420 if (flushed == 0) { 3421 /* 3422 * Could not find any buffers without rollback 3423 * dependencies, so just write the first one 3424 * in the hopes of eventually making progress. 3425 */ 3426 if (vp != NULL && target > 2) 3427 target /= 2; 3428 flushbufqueues(vp, bd, target, 1); 3429 } 3430 return (flushed); 3431 } 3432 3433 static void 3434 buf_daemon_shutdown(void *arg __unused, int howto __unused) 3435 { 3436 int error; 3437 3438 if (KERNEL_PANICKED()) 3439 return; 3440 3441 mtx_lock(&bdlock); 3442 bd_shutdown = true; 3443 wakeup(&bd_request); 3444 error = msleep(&bd_shutdown, &bdlock, 0, "buf_daemon_shutdown", 3445 60 * hz); 3446 mtx_unlock(&bdlock); 3447 if (error != 0) 3448 printf("bufdaemon wait error: %d\n", error); 3449 } 3450 3451 static void 3452 buf_daemon(void) 3453 { 3454 struct bufdomain *bd; 3455 int speedupreq; 3456 int lodirty; 3457 int i; 3458 3459 /* 3460 * This process needs to be suspended prior to shutdown sync. 3461 */ 3462 EVENTHANDLER_REGISTER(shutdown_pre_sync, buf_daemon_shutdown, NULL, 3463 SHUTDOWN_PRI_LAST + 100); 3464 3465 /* 3466 * Start the buf clean daemons as children threads. 3467 */ 3468 for (i = 0 ; i < buf_domains; i++) { 3469 int error; 3470 3471 error = kthread_add((void (*)(void *))bufspace_daemon, 3472 &bdomain[i], curproc, NULL, 0, 0, "bufspacedaemon-%d", i); 3473 if (error) 3474 panic("error %d spawning bufspace daemon", error); 3475 } 3476 3477 /* 3478 * This process is allowed to take the buffer cache to the limit 3479 */ 3480 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED; 3481 mtx_lock(&bdlock); 3482 while (!bd_shutdown) { 3483 bd_request = 0; 3484 mtx_unlock(&bdlock); 3485 3486 /* 3487 * Save speedupreq for this pass and reset to capture new 3488 * requests. 3489 */ 3490 speedupreq = bd_speedupreq; 3491 bd_speedupreq = 0; 3492 3493 /* 3494 * Flush each domain sequentially according to its level and 3495 * the speedup request. 3496 */ 3497 for (i = 0; i < buf_domains; i++) { 3498 bd = &bdomain[i]; 3499 if (speedupreq) 3500 lodirty = bd->bd_numdirtybuffers / 2; 3501 else 3502 lodirty = bd->bd_lodirtybuffers; 3503 while (bd->bd_numdirtybuffers > lodirty) { 3504 if (buf_flush(NULL, bd, 3505 bd->bd_numdirtybuffers - lodirty) == 0) 3506 break; 3507 kern_yield(PRI_USER); 3508 } 3509 } 3510 3511 /* 3512 * Only clear bd_request if we have reached our low water 3513 * mark. The buf_daemon normally waits 1 second and 3514 * then incrementally flushes any dirty buffers that have 3515 * built up, within reason. 3516 * 3517 * If we were unable to hit our low water mark and couldn't 3518 * find any flushable buffers, we sleep for a short period 3519 * to avoid endless loops on unlockable buffers. 3520 */ 3521 mtx_lock(&bdlock); 3522 if (bd_shutdown) 3523 break; 3524 if (BIT_EMPTY(BUF_DOMAINS, &bdlodirty)) { 3525 /* 3526 * We reached our low water mark, reset the 3527 * request and sleep until we are needed again. 3528 * The sleep is just so the suspend code works. 3529 */ 3530 bd_request = 0; 3531 /* 3532 * Do an extra wakeup in case dirty threshold 3533 * changed via sysctl and the explicit transition 3534 * out of shortfall was missed. 3535 */ 3536 bdirtywakeup(); 3537 if (runningbufspace <= lorunningspace) 3538 runningwakeup(); 3539 msleep(&bd_request, &bdlock, PVM, "psleep", hz); 3540 } else { 3541 /* 3542 * We couldn't find any flushable dirty buffers but 3543 * still have too many dirty buffers, we 3544 * have to sleep and try again. (rare) 3545 */ 3546 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10); 3547 } 3548 } 3549 wakeup(&bd_shutdown); 3550 mtx_unlock(&bdlock); 3551 kthread_exit(); 3552 } 3553 3554 /* 3555 * flushbufqueues: 3556 * 3557 * Try to flush a buffer in the dirty queue. We must be careful to 3558 * free up B_INVAL buffers instead of write them, which NFS is 3559 * particularly sensitive to. 3560 */ 3561 static int flushwithdeps = 0; 3562 SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW | CTLFLAG_STATS, 3563 &flushwithdeps, 0, 3564 "Number of buffers flushed with dependencies that require rollbacks"); 3565 3566 static int 3567 flushbufqueues(struct vnode *lvp, struct bufdomain *bd, int target, 3568 int flushdeps) 3569 { 3570 struct bufqueue *bq; 3571 struct buf *sentinel; 3572 struct vnode *vp; 3573 struct mount *mp; 3574 struct buf *bp; 3575 int hasdeps; 3576 int flushed; 3577 int error; 3578 bool unlock; 3579 3580 flushed = 0; 3581 bq = &bd->bd_dirtyq; 3582 bp = NULL; 3583 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO); 3584 sentinel->b_qindex = QUEUE_SENTINEL; 3585 BQ_LOCK(bq); 3586 TAILQ_INSERT_HEAD(&bq->bq_queue, sentinel, b_freelist); 3587 BQ_UNLOCK(bq); 3588 while (flushed != target) { 3589 maybe_yield(); 3590 BQ_LOCK(bq); 3591 bp = TAILQ_NEXT(sentinel, b_freelist); 3592 if (bp != NULL) { 3593 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3594 TAILQ_INSERT_AFTER(&bq->bq_queue, bp, sentinel, 3595 b_freelist); 3596 } else { 3597 BQ_UNLOCK(bq); 3598 break; 3599 } 3600 /* 3601 * Skip sentinels inserted by other invocations of the 3602 * flushbufqueues(), taking care to not reorder them. 3603 * 3604 * Only flush the buffers that belong to the 3605 * vnode locked by the curthread. 3606 */ 3607 if (bp->b_qindex == QUEUE_SENTINEL || (lvp != NULL && 3608 bp->b_vp != lvp)) { 3609 BQ_UNLOCK(bq); 3610 continue; 3611 } 3612 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 3613 BQ_UNLOCK(bq); 3614 if (error != 0) 3615 continue; 3616 3617 /* 3618 * BKGRDINPROG can only be set with the buf and bufobj 3619 * locks both held. We tolerate a race to clear it here. 3620 */ 3621 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 || 3622 (bp->b_flags & B_DELWRI) == 0) { 3623 BUF_UNLOCK(bp); 3624 continue; 3625 } 3626 if (bp->b_flags & B_INVAL) { 3627 bremfreef(bp); 3628 brelse(bp); 3629 flushed++; 3630 continue; 3631 } 3632 3633 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) { 3634 if (flushdeps == 0) { 3635 BUF_UNLOCK(bp); 3636 continue; 3637 } 3638 hasdeps = 1; 3639 } else 3640 hasdeps = 0; 3641 /* 3642 * We must hold the lock on a vnode before writing 3643 * one of its buffers. Otherwise we may confuse, or 3644 * in the case of a snapshot vnode, deadlock the 3645 * system. 3646 * 3647 * The lock order here is the reverse of the normal 3648 * of vnode followed by buf lock. This is ok because 3649 * the NOWAIT will prevent deadlock. 3650 */ 3651 vp = bp->b_vp; 3652 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { 3653 BUF_UNLOCK(bp); 3654 continue; 3655 } 3656 if (lvp == NULL) { 3657 unlock = true; 3658 error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); 3659 } else { 3660 ASSERT_VOP_LOCKED(vp, "getbuf"); 3661 unlock = false; 3662 error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : 3663 vn_lock(vp, LK_TRYUPGRADE); 3664 } 3665 if (error == 0) { 3666 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", 3667 bp, bp->b_vp, bp->b_flags); 3668 if (curproc == bufdaemonproc) { 3669 vfs_bio_awrite(bp); 3670 } else { 3671 bremfree(bp); 3672 bwrite(bp); 3673 counter_u64_add(notbufdflushes, 1); 3674 } 3675 vn_finished_write(mp); 3676 if (unlock) 3677 VOP_UNLOCK(vp); 3678 flushwithdeps += hasdeps; 3679 flushed++; 3680 3681 /* 3682 * Sleeping on runningbufspace while holding 3683 * vnode lock leads to deadlock. 3684 */ 3685 if (curproc == bufdaemonproc && 3686 runningbufspace > hirunningspace) 3687 waitrunningbufspace(); 3688 continue; 3689 } 3690 vn_finished_write(mp); 3691 BUF_UNLOCK(bp); 3692 } 3693 BQ_LOCK(bq); 3694 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3695 BQ_UNLOCK(bq); 3696 free(sentinel, M_TEMP); 3697 return (flushed); 3698 } 3699 3700 /* 3701 * Check to see if a block is currently memory resident. 3702 */ 3703 struct buf * 3704 incore(struct bufobj *bo, daddr_t blkno) 3705 { 3706 return (gbincore_unlocked(bo, blkno)); 3707 } 3708 3709 /* 3710 * Returns true if no I/O is needed to access the 3711 * associated VM object. This is like incore except 3712 * it also hunts around in the VM system for the data. 3713 */ 3714 bool 3715 inmem(struct vnode * vp, daddr_t blkno) 3716 { 3717 vm_object_t obj; 3718 vm_offset_t toff, tinc, size; 3719 vm_page_t m, n; 3720 vm_ooffset_t off; 3721 int valid; 3722 3723 ASSERT_VOP_LOCKED(vp, "inmem"); 3724 3725 if (incore(&vp->v_bufobj, blkno)) 3726 return (true); 3727 if (vp->v_mount == NULL) 3728 return (false); 3729 obj = vp->v_object; 3730 if (obj == NULL) 3731 return (false); 3732 3733 size = PAGE_SIZE; 3734 if (size > vp->v_mount->mnt_stat.f_iosize) 3735 size = vp->v_mount->mnt_stat.f_iosize; 3736 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 3737 3738 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 3739 m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3740 recheck: 3741 if (m == NULL) 3742 return (false); 3743 3744 tinc = size; 3745 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 3746 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 3747 /* 3748 * Consider page validity only if page mapping didn't change 3749 * during the check. 3750 */ 3751 valid = vm_page_is_valid(m, 3752 (vm_offset_t)((toff + off) & PAGE_MASK), tinc); 3753 n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3754 if (m != n) { 3755 m = n; 3756 goto recheck; 3757 } 3758 if (!valid) 3759 return (false); 3760 } 3761 return (true); 3762 } 3763 3764 /* 3765 * Set the dirty range for a buffer based on the status of the dirty 3766 * bits in the pages comprising the buffer. The range is limited 3767 * to the size of the buffer. 3768 * 3769 * Tell the VM system that the pages associated with this buffer 3770 * are clean. This is used for delayed writes where the data is 3771 * going to go to disk eventually without additional VM intevention. 3772 * 3773 * Note that while we only really need to clean through to b_bcount, we 3774 * just go ahead and clean through to b_bufsize. 3775 */ 3776 static void 3777 vfs_clean_pages_dirty_buf(struct buf *bp) 3778 { 3779 vm_ooffset_t foff, noff, eoff; 3780 vm_page_t m; 3781 int i; 3782 3783 if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0) 3784 return; 3785 3786 foff = bp->b_offset; 3787 KASSERT(bp->b_offset != NOOFFSET, 3788 ("vfs_clean_pages_dirty_buf: no buffer offset")); 3789 3790 vfs_busy_pages_acquire(bp); 3791 vfs_setdirty_range(bp); 3792 for (i = 0; i < bp->b_npages; i++) { 3793 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3794 eoff = noff; 3795 if (eoff > bp->b_offset + bp->b_bufsize) 3796 eoff = bp->b_offset + bp->b_bufsize; 3797 m = bp->b_pages[i]; 3798 vfs_page_set_validclean(bp, foff, m); 3799 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */ 3800 foff = noff; 3801 } 3802 vfs_busy_pages_release(bp); 3803 } 3804 3805 static void 3806 vfs_setdirty_range(struct buf *bp) 3807 { 3808 vm_offset_t boffset; 3809 vm_offset_t eoffset; 3810 int i; 3811 3812 /* 3813 * test the pages to see if they have been modified directly 3814 * by users through the VM system. 3815 */ 3816 for (i = 0; i < bp->b_npages; i++) 3817 vm_page_test_dirty(bp->b_pages[i]); 3818 3819 /* 3820 * Calculate the encompassing dirty range, boffset and eoffset, 3821 * (eoffset - boffset) bytes. 3822 */ 3823 3824 for (i = 0; i < bp->b_npages; i++) { 3825 if (bp->b_pages[i]->dirty) 3826 break; 3827 } 3828 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3829 3830 for (i = bp->b_npages - 1; i >= 0; --i) { 3831 if (bp->b_pages[i]->dirty) { 3832 break; 3833 } 3834 } 3835 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3836 3837 /* 3838 * Fit it to the buffer. 3839 */ 3840 3841 if (eoffset > bp->b_bcount) 3842 eoffset = bp->b_bcount; 3843 3844 /* 3845 * If we have a good dirty range, merge with the existing 3846 * dirty range. 3847 */ 3848 3849 if (boffset < eoffset) { 3850 if (bp->b_dirtyoff > boffset) 3851 bp->b_dirtyoff = boffset; 3852 if (bp->b_dirtyend < eoffset) 3853 bp->b_dirtyend = eoffset; 3854 } 3855 } 3856 3857 /* 3858 * Allocate the KVA mapping for an existing buffer. 3859 * If an unmapped buffer is provided but a mapped buffer is requested, take 3860 * also care to properly setup mappings between pages and KVA. 3861 */ 3862 static void 3863 bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags) 3864 { 3865 int bsize, maxsize, need_mapping, need_kva; 3866 off_t offset; 3867 3868 need_mapping = bp->b_data == unmapped_buf && 3869 (gbflags & GB_UNMAPPED) == 0; 3870 need_kva = bp->b_kvabase == unmapped_buf && 3871 bp->b_data == unmapped_buf && 3872 (gbflags & GB_KVAALLOC) != 0; 3873 if (!need_mapping && !need_kva) 3874 return; 3875 3876 BUF_CHECK_UNMAPPED(bp); 3877 3878 if (need_mapping && bp->b_kvabase != unmapped_buf) { 3879 /* 3880 * Buffer is not mapped, but the KVA was already 3881 * reserved at the time of the instantiation. Use the 3882 * allocated space. 3883 */ 3884 goto has_addr; 3885 } 3886 3887 /* 3888 * Calculate the amount of the address space we would reserve 3889 * if the buffer was mapped. 3890 */ 3891 bsize = vn_isdisk(bp->b_vp) ? DEV_BSIZE : bp->b_bufobj->bo_bsize; 3892 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 3893 offset = blkno * bsize; 3894 maxsize = size + (offset & PAGE_MASK); 3895 maxsize = imax(maxsize, bsize); 3896 3897 while (bufkva_alloc(bp, maxsize, gbflags) != 0) { 3898 if ((gbflags & GB_NOWAIT_BD) != 0) { 3899 /* 3900 * XXXKIB: defragmentation cannot 3901 * succeed, not sure what else to do. 3902 */ 3903 panic("GB_NOWAIT_BD and GB_UNMAPPED %p", bp); 3904 } 3905 counter_u64_add(mappingrestarts, 1); 3906 bufspace_wait(bufdomain(bp), bp->b_vp, gbflags, 0, 0); 3907 } 3908 has_addr: 3909 if (need_mapping) { 3910 /* b_offset is handled by bpmap_qenter. */ 3911 bp->b_data = bp->b_kvabase; 3912 BUF_CHECK_MAPPED(bp); 3913 bpmap_qenter(bp); 3914 } 3915 } 3916 3917 struct buf * 3918 getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo, 3919 int flags) 3920 { 3921 struct buf *bp; 3922 int error; 3923 3924 error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp); 3925 if (error != 0) 3926 return (NULL); 3927 return (bp); 3928 } 3929 3930 /* 3931 * getblkx: 3932 * 3933 * Get a block given a specified block and offset into a file/device. 3934 * The buffers B_DONE bit will be cleared on return, making it almost 3935 * ready for an I/O initiation. B_INVAL may or may not be set on 3936 * return. The caller should clear B_INVAL prior to initiating a 3937 * READ. 3938 * 3939 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for 3940 * an existing buffer. 3941 * 3942 * For a VMIO buffer, B_CACHE is modified according to the backing VM. 3943 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set 3944 * and then cleared based on the backing VM. If the previous buffer is 3945 * non-0-sized but invalid, B_CACHE will be cleared. 3946 * 3947 * If getblk() must create a new buffer, the new buffer is returned with 3948 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which 3949 * case it is returned with B_INVAL clear and B_CACHE set based on the 3950 * backing VM. 3951 * 3952 * getblk() also forces a bwrite() for any B_DELWRI buffer whose 3953 * B_CACHE bit is clear. 3954 * 3955 * What this means, basically, is that the caller should use B_CACHE to 3956 * determine whether the buffer is fully valid or not and should clear 3957 * B_INVAL prior to issuing a read. If the caller intends to validate 3958 * the buffer by loading its data area with something, the caller needs 3959 * to clear B_INVAL. If the caller does this without issuing an I/O, 3960 * the caller should set B_CACHE ( as an optimization ), else the caller 3961 * should issue the I/O and biodone() will set B_CACHE if the I/O was 3962 * a write attempt or if it was a successful read. If the caller 3963 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR 3964 * prior to issuing the READ. biodone() will *not* clear B_INVAL. 3965 * 3966 * The blkno parameter is the logical block being requested. Normally 3967 * the mapping of logical block number to disk block address is done 3968 * by calling VOP_BMAP(). However, if the mapping is already known, the 3969 * disk block address can be passed using the dblkno parameter. If the 3970 * disk block address is not known, then the same value should be passed 3971 * for blkno and dblkno. 3972 */ 3973 int 3974 getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag, 3975 int slptimeo, int flags, struct buf **bpp) 3976 { 3977 struct buf *bp; 3978 struct bufobj *bo; 3979 daddr_t d_blkno; 3980 int bsize, error, maxsize, vmio; 3981 off_t offset; 3982 3983 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size); 3984 KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3985 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3986 if (vp->v_type != VCHR) 3987 ASSERT_VOP_LOCKED(vp, "getblk"); 3988 if (size > maxbcachebuf) 3989 panic("getblk: size(%d) > maxbcachebuf(%d)\n", size, 3990 maxbcachebuf); 3991 if (!unmapped_buf_allowed) 3992 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3993 3994 bo = &vp->v_bufobj; 3995 d_blkno = dblkno; 3996 3997 /* Attempt lockless lookup first. */ 3998 bp = gbincore_unlocked(bo, blkno); 3999 if (bp == NULL) { 4000 /* 4001 * With GB_NOCREAT we must be sure about not finding the buffer 4002 * as it may have been reassigned during unlocked lookup. 4003 */ 4004 if ((flags & GB_NOCREAT) != 0) 4005 goto loop; 4006 goto newbuf_unlocked; 4007 } 4008 4009 error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL, "getblku", 0, 4010 0); 4011 if (error != 0) 4012 goto loop; 4013 4014 /* Verify buf identify has not changed since lookup. */ 4015 if (bp->b_bufobj == bo && bp->b_lblkno == blkno) 4016 goto foundbuf_fastpath; 4017 4018 /* It changed, fallback to locked lookup. */ 4019 BUF_UNLOCK_RAW(bp); 4020 4021 loop: 4022 BO_RLOCK(bo); 4023 bp = gbincore(bo, blkno); 4024 if (bp != NULL) { 4025 int lockflags; 4026 4027 /* 4028 * Buffer is in-core. If the buffer is not busy nor managed, 4029 * it must be on a queue. 4030 */ 4031 lockflags = LK_EXCLUSIVE | LK_INTERLOCK | 4032 ((flags & GB_LOCK_NOWAIT) != 0 ? LK_NOWAIT : LK_SLEEPFAIL); 4033 #ifdef WITNESS 4034 lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0; 4035 #endif 4036 4037 error = BUF_TIMELOCK(bp, lockflags, 4038 BO_LOCKPTR(bo), "getblk", slpflag, slptimeo); 4039 4040 /* 4041 * If we slept and got the lock we have to restart in case 4042 * the buffer changed identities. 4043 */ 4044 if (error == ENOLCK) 4045 goto loop; 4046 /* We timed out or were interrupted. */ 4047 else if (error != 0) 4048 return (error); 4049 4050 foundbuf_fastpath: 4051 /* If recursed, assume caller knows the rules. */ 4052 if (BUF_LOCKRECURSED(bp)) 4053 goto end; 4054 4055 /* 4056 * The buffer is locked. B_CACHE is cleared if the buffer is 4057 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set 4058 * and for a VMIO buffer B_CACHE is adjusted according to the 4059 * backing VM cache. 4060 */ 4061 if (bp->b_flags & B_INVAL) 4062 bp->b_flags &= ~B_CACHE; 4063 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0) 4064 bp->b_flags |= B_CACHE; 4065 if (bp->b_flags & B_MANAGED) 4066 MPASS(bp->b_qindex == QUEUE_NONE); 4067 else 4068 bremfree(bp); 4069 4070 /* 4071 * check for size inconsistencies for non-VMIO case. 4072 */ 4073 if (bp->b_bcount != size) { 4074 if ((bp->b_flags & B_VMIO) == 0 || 4075 (size > bp->b_kvasize)) { 4076 if (bp->b_flags & B_DELWRI) { 4077 bp->b_flags |= B_NOCACHE; 4078 bwrite(bp); 4079 } else { 4080 if (LIST_EMPTY(&bp->b_dep)) { 4081 bp->b_flags |= B_RELBUF; 4082 brelse(bp); 4083 } else { 4084 bp->b_flags |= B_NOCACHE; 4085 bwrite(bp); 4086 } 4087 } 4088 goto loop; 4089 } 4090 } 4091 4092 /* 4093 * Handle the case of unmapped buffer which should 4094 * become mapped, or the buffer for which KVA 4095 * reservation is requested. 4096 */ 4097 bp_unmapped_get_kva(bp, blkno, size, flags); 4098 4099 /* 4100 * If the size is inconsistent in the VMIO case, we can resize 4101 * the buffer. This might lead to B_CACHE getting set or 4102 * cleared. If the size has not changed, B_CACHE remains 4103 * unchanged from its previous state. 4104 */ 4105 allocbuf(bp, size); 4106 4107 KASSERT(bp->b_offset != NOOFFSET, 4108 ("getblk: no buffer offset")); 4109 4110 /* 4111 * A buffer with B_DELWRI set and B_CACHE clear must 4112 * be committed before we can return the buffer in 4113 * order to prevent the caller from issuing a read 4114 * ( due to B_CACHE not being set ) and overwriting 4115 * it. 4116 * 4117 * Most callers, including NFS and FFS, need this to 4118 * operate properly either because they assume they 4119 * can issue a read if B_CACHE is not set, or because 4120 * ( for example ) an uncached B_DELWRI might loop due 4121 * to softupdates re-dirtying the buffer. In the latter 4122 * case, B_CACHE is set after the first write completes, 4123 * preventing further loops. 4124 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE 4125 * above while extending the buffer, we cannot allow the 4126 * buffer to remain with B_CACHE set after the write 4127 * completes or it will represent a corrupt state. To 4128 * deal with this we set B_NOCACHE to scrap the buffer 4129 * after the write. 4130 * 4131 * We might be able to do something fancy, like setting 4132 * B_CACHE in bwrite() except if B_DELWRI is already set, 4133 * so the below call doesn't set B_CACHE, but that gets real 4134 * confusing. This is much easier. 4135 */ 4136 4137 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) { 4138 bp->b_flags |= B_NOCACHE; 4139 bwrite(bp); 4140 goto loop; 4141 } 4142 bp->b_flags &= ~B_DONE; 4143 } else { 4144 /* 4145 * Buffer is not in-core, create new buffer. The buffer 4146 * returned by getnewbuf() is locked. Note that the returned 4147 * buffer is also considered valid (not marked B_INVAL). 4148 */ 4149 BO_RUNLOCK(bo); 4150 newbuf_unlocked: 4151 /* 4152 * If the user does not want us to create the buffer, bail out 4153 * here. 4154 */ 4155 if (flags & GB_NOCREAT) 4156 return (EEXIST); 4157 4158 bsize = vn_isdisk(vp) ? DEV_BSIZE : bo->bo_bsize; 4159 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 4160 offset = blkno * bsize; 4161 vmio = vp->v_object != NULL; 4162 if (vmio) { 4163 maxsize = size + (offset & PAGE_MASK); 4164 } else { 4165 maxsize = size; 4166 /* Do not allow non-VMIO notmapped buffers. */ 4167 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 4168 } 4169 maxsize = imax(maxsize, bsize); 4170 if ((flags & GB_NOSPARSE) != 0 && vmio && 4171 !vn_isdisk(vp)) { 4172 error = VOP_BMAP(vp, blkno, NULL, &d_blkno, 0, 0); 4173 KASSERT(error != EOPNOTSUPP, 4174 ("GB_NOSPARSE from fs not supporting bmap, vp %p", 4175 vp)); 4176 if (error != 0) 4177 return (error); 4178 if (d_blkno == -1) 4179 return (EJUSTRETURN); 4180 } 4181 4182 bp = getnewbuf(vp, slpflag, slptimeo, maxsize, flags); 4183 if (bp == NULL) { 4184 if (slpflag || slptimeo) 4185 return (ETIMEDOUT); 4186 /* 4187 * XXX This is here until the sleep path is diagnosed 4188 * enough to work under very low memory conditions. 4189 * 4190 * There's an issue on low memory, 4BSD+non-preempt 4191 * systems (eg MIPS routers with 32MB RAM) where buffer 4192 * exhaustion occurs without sleeping for buffer 4193 * reclaimation. This just sticks in a loop and 4194 * constantly attempts to allocate a buffer, which 4195 * hits exhaustion and tries to wakeup bufdaemon. 4196 * This never happens because we never yield. 4197 * 4198 * The real solution is to identify and fix these cases 4199 * so we aren't effectively busy-waiting in a loop 4200 * until the reclaimation path has cycles to run. 4201 */ 4202 kern_yield(PRI_USER); 4203 goto loop; 4204 } 4205 4206 /* 4207 * This code is used to make sure that a buffer is not 4208 * created while the getnewbuf routine is blocked. 4209 * This can be a problem whether the vnode is locked or not. 4210 * If the buffer is created out from under us, we have to 4211 * throw away the one we just created. 4212 * 4213 * Note: this must occur before we associate the buffer 4214 * with the vp especially considering limitations in 4215 * the splay tree implementation when dealing with duplicate 4216 * lblkno's. 4217 */ 4218 BO_LOCK(bo); 4219 if (gbincore(bo, blkno)) { 4220 BO_UNLOCK(bo); 4221 bp->b_flags |= B_INVAL; 4222 bufspace_release(bufdomain(bp), maxsize); 4223 brelse(bp); 4224 goto loop; 4225 } 4226 4227 /* 4228 * Insert the buffer into the hash, so that it can 4229 * be found by incore. 4230 */ 4231 bp->b_lblkno = blkno; 4232 bp->b_blkno = d_blkno; 4233 bp->b_offset = offset; 4234 bgetvp(vp, bp); 4235 BO_UNLOCK(bo); 4236 4237 /* 4238 * set B_VMIO bit. allocbuf() the buffer bigger. Since the 4239 * buffer size starts out as 0, B_CACHE will be set by 4240 * allocbuf() for the VMIO case prior to it testing the 4241 * backing store for validity. 4242 */ 4243 4244 if (vmio) { 4245 bp->b_flags |= B_VMIO; 4246 KASSERT(vp->v_object == bp->b_bufobj->bo_object, 4247 ("ARGH! different b_bufobj->bo_object %p %p %p\n", 4248 bp, vp->v_object, bp->b_bufobj->bo_object)); 4249 } else { 4250 bp->b_flags &= ~B_VMIO; 4251 KASSERT(bp->b_bufobj->bo_object == NULL, 4252 ("ARGH! has b_bufobj->bo_object %p %p\n", 4253 bp, bp->b_bufobj->bo_object)); 4254 BUF_CHECK_MAPPED(bp); 4255 } 4256 4257 allocbuf(bp, size); 4258 bufspace_release(bufdomain(bp), maxsize); 4259 bp->b_flags &= ~B_DONE; 4260 } 4261 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp); 4262 end: 4263 buf_track(bp, __func__); 4264 KASSERT(bp->b_bufobj == bo, 4265 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo)); 4266 *bpp = bp; 4267 return (0); 4268 } 4269 4270 /* 4271 * Get an empty, disassociated buffer of given size. The buffer is initially 4272 * set to B_INVAL. 4273 */ 4274 struct buf * 4275 geteblk(int size, int flags) 4276 { 4277 struct buf *bp; 4278 int maxsize; 4279 4280 maxsize = (size + BKVAMASK) & ~BKVAMASK; 4281 while ((bp = getnewbuf(NULL, 0, 0, maxsize, flags)) == NULL) { 4282 if ((flags & GB_NOWAIT_BD) && 4283 (curthread->td_pflags & TDP_BUFNEED) != 0) 4284 return (NULL); 4285 } 4286 allocbuf(bp, size); 4287 bufspace_release(bufdomain(bp), maxsize); 4288 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 4289 return (bp); 4290 } 4291 4292 /* 4293 * Truncate the backing store for a non-vmio buffer. 4294 */ 4295 static void 4296 vfs_nonvmio_truncate(struct buf *bp, int newbsize) 4297 { 4298 4299 if (bp->b_flags & B_MALLOC) { 4300 /* 4301 * malloced buffers are not shrunk 4302 */ 4303 if (newbsize == 0) { 4304 bufmallocadjust(bp, 0); 4305 free(bp->b_data, M_BIOBUF); 4306 bp->b_data = bp->b_kvabase; 4307 bp->b_flags &= ~B_MALLOC; 4308 } 4309 return; 4310 } 4311 vm_hold_free_pages(bp, newbsize); 4312 bufspace_adjust(bp, newbsize); 4313 } 4314 4315 /* 4316 * Extend the backing for a non-VMIO buffer. 4317 */ 4318 static void 4319 vfs_nonvmio_extend(struct buf *bp, int newbsize) 4320 { 4321 caddr_t origbuf; 4322 int origbufsize; 4323 4324 /* 4325 * We only use malloced memory on the first allocation. 4326 * and revert to page-allocated memory when the buffer 4327 * grows. 4328 * 4329 * There is a potential smp race here that could lead 4330 * to bufmallocspace slightly passing the max. It 4331 * is probably extremely rare and not worth worrying 4332 * over. 4333 */ 4334 if (bp->b_bufsize == 0 && newbsize <= PAGE_SIZE/2 && 4335 bufmallocspace < maxbufmallocspace) { 4336 bp->b_data = malloc(newbsize, M_BIOBUF, M_WAITOK); 4337 bp->b_flags |= B_MALLOC; 4338 bufmallocadjust(bp, newbsize); 4339 return; 4340 } 4341 4342 /* 4343 * If the buffer is growing on its other-than-first 4344 * allocation then we revert to the page-allocation 4345 * scheme. 4346 */ 4347 origbuf = NULL; 4348 origbufsize = 0; 4349 if (bp->b_flags & B_MALLOC) { 4350 origbuf = bp->b_data; 4351 origbufsize = bp->b_bufsize; 4352 bp->b_data = bp->b_kvabase; 4353 bufmallocadjust(bp, 0); 4354 bp->b_flags &= ~B_MALLOC; 4355 newbsize = round_page(newbsize); 4356 } 4357 vm_hold_load_pages(bp, (vm_offset_t) bp->b_data + bp->b_bufsize, 4358 (vm_offset_t) bp->b_data + newbsize); 4359 if (origbuf != NULL) { 4360 bcopy(origbuf, bp->b_data, origbufsize); 4361 free(origbuf, M_BIOBUF); 4362 } 4363 bufspace_adjust(bp, newbsize); 4364 } 4365 4366 /* 4367 * This code constitutes the buffer memory from either anonymous system 4368 * memory (in the case of non-VMIO operations) or from an associated 4369 * VM object (in the case of VMIO operations). This code is able to 4370 * resize a buffer up or down. 4371 * 4372 * Note that this code is tricky, and has many complications to resolve 4373 * deadlock or inconsistent data situations. Tread lightly!!! 4374 * There are B_CACHE and B_DELWRI interactions that must be dealt with by 4375 * the caller. Calling this code willy nilly can result in the loss of data. 4376 * 4377 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with 4378 * B_CACHE for the non-VMIO case. 4379 */ 4380 int 4381 allocbuf(struct buf *bp, int size) 4382 { 4383 int newbsize; 4384 4385 if (bp->b_bcount == size) 4386 return (1); 4387 4388 KASSERT(bp->b_kvasize == 0 || bp->b_kvasize >= size, 4389 ("allocbuf: buffer too small %p %#x %#x", 4390 bp, bp->b_kvasize, size)); 4391 4392 newbsize = roundup2(size, DEV_BSIZE); 4393 if ((bp->b_flags & B_VMIO) == 0) { 4394 if ((bp->b_flags & B_MALLOC) == 0) 4395 newbsize = round_page(newbsize); 4396 /* 4397 * Just get anonymous memory from the kernel. Don't 4398 * mess with B_CACHE. 4399 */ 4400 if (newbsize < bp->b_bufsize) 4401 vfs_nonvmio_truncate(bp, newbsize); 4402 else if (newbsize > bp->b_bufsize) 4403 vfs_nonvmio_extend(bp, newbsize); 4404 } else { 4405 int desiredpages; 4406 4407 desiredpages = size == 0 ? 0 : 4408 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 4409 4410 KASSERT((bp->b_flags & B_MALLOC) == 0, 4411 ("allocbuf: VMIO buffer can't be malloced %p", bp)); 4412 4413 /* 4414 * Set B_CACHE initially if buffer is 0 length or will become 4415 * 0-length. 4416 */ 4417 if (size == 0 || bp->b_bufsize == 0) 4418 bp->b_flags |= B_CACHE; 4419 4420 if (newbsize < bp->b_bufsize) 4421 vfs_vmio_truncate(bp, desiredpages); 4422 /* XXX This looks as if it should be newbsize > b_bufsize */ 4423 else if (size > bp->b_bcount) 4424 vfs_vmio_extend(bp, desiredpages, size); 4425 bufspace_adjust(bp, newbsize); 4426 } 4427 bp->b_bcount = size; /* requested buffer size. */ 4428 return (1); 4429 } 4430 4431 extern int inflight_transient_maps; 4432 4433 static struct bio_queue nondump_bios; 4434 4435 void 4436 biodone(struct bio *bp) 4437 { 4438 struct mtx *mtxp; 4439 void (*done)(struct bio *); 4440 vm_offset_t start, end; 4441 4442 biotrack(bp, __func__); 4443 4444 /* 4445 * Avoid completing I/O when dumping after a panic since that may 4446 * result in a deadlock in the filesystem or pager code. Note that 4447 * this doesn't affect dumps that were started manually since we aim 4448 * to keep the system usable after it has been resumed. 4449 */ 4450 if (__predict_false(dumping && SCHEDULER_STOPPED())) { 4451 TAILQ_INSERT_HEAD(&nondump_bios, bp, bio_queue); 4452 return; 4453 } 4454 if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { 4455 bp->bio_flags &= ~BIO_TRANSIENT_MAPPING; 4456 bp->bio_flags |= BIO_UNMAPPED; 4457 start = trunc_page((vm_offset_t)bp->bio_data); 4458 end = round_page((vm_offset_t)bp->bio_data + bp->bio_length); 4459 bp->bio_data = unmapped_buf; 4460 pmap_qremove(start, atop(end - start)); 4461 vmem_free(transient_arena, start, end - start); 4462 atomic_add_int(&inflight_transient_maps, -1); 4463 } 4464 done = bp->bio_done; 4465 /* 4466 * The check for done == biodone is to allow biodone to be 4467 * used as a bio_done routine. 4468 */ 4469 if (done == NULL || done == biodone) { 4470 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4471 mtx_lock(mtxp); 4472 bp->bio_flags |= BIO_DONE; 4473 wakeup(bp); 4474 mtx_unlock(mtxp); 4475 } else 4476 done(bp); 4477 } 4478 4479 /* 4480 * Wait for a BIO to finish. 4481 */ 4482 int 4483 biowait(struct bio *bp, const char *wmesg) 4484 { 4485 struct mtx *mtxp; 4486 4487 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4488 mtx_lock(mtxp); 4489 while ((bp->bio_flags & BIO_DONE) == 0) 4490 msleep(bp, mtxp, PRIBIO, wmesg, 0); 4491 mtx_unlock(mtxp); 4492 if (bp->bio_error != 0) 4493 return (bp->bio_error); 4494 if (!(bp->bio_flags & BIO_ERROR)) 4495 return (0); 4496 return (EIO); 4497 } 4498 4499 void 4500 biofinish(struct bio *bp, struct devstat *stat, int error) 4501 { 4502 4503 if (error) { 4504 bp->bio_error = error; 4505 bp->bio_flags |= BIO_ERROR; 4506 } 4507 if (stat != NULL) 4508 devstat_end_transaction_bio(stat, bp); 4509 biodone(bp); 4510 } 4511 4512 #if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING) 4513 void 4514 biotrack_buf(struct bio *bp, const char *location) 4515 { 4516 4517 buf_track(bp->bio_track_bp, location); 4518 } 4519 #endif 4520 4521 /* 4522 * bufwait: 4523 * 4524 * Wait for buffer I/O completion, returning error status. The buffer 4525 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR 4526 * error and cleared. 4527 */ 4528 int 4529 bufwait(struct buf *bp) 4530 { 4531 if (bp->b_iocmd == BIO_READ) 4532 bwait(bp, PRIBIO, "biord"); 4533 else 4534 bwait(bp, PRIBIO, "biowr"); 4535 if (bp->b_flags & B_EINTR) { 4536 bp->b_flags &= ~B_EINTR; 4537 return (EINTR); 4538 } 4539 if (bp->b_ioflags & BIO_ERROR) { 4540 return (bp->b_error ? bp->b_error : EIO); 4541 } else { 4542 return (0); 4543 } 4544 } 4545 4546 /* 4547 * bufdone: 4548 * 4549 * Finish I/O on a buffer, optionally calling a completion function. 4550 * This is usually called from an interrupt so process blocking is 4551 * not allowed. 4552 * 4553 * biodone is also responsible for setting B_CACHE in a B_VMIO bp. 4554 * In a non-VMIO bp, B_CACHE will be set on the next getblk() 4555 * assuming B_INVAL is clear. 4556 * 4557 * For the VMIO case, we set B_CACHE if the op was a read and no 4558 * read error occurred, or if the op was a write. B_CACHE is never 4559 * set if the buffer is invalid or otherwise uncacheable. 4560 * 4561 * bufdone does not mess with B_INVAL, allowing the I/O routine or the 4562 * initiator to leave B_INVAL set to brelse the buffer out of existence 4563 * in the biodone routine. 4564 */ 4565 void 4566 bufdone(struct buf *bp) 4567 { 4568 struct bufobj *dropobj; 4569 void (*biodone)(struct buf *); 4570 4571 buf_track(bp, __func__); 4572 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 4573 dropobj = NULL; 4574 4575 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp)); 4576 4577 runningbufwakeup(bp); 4578 if (bp->b_iocmd == BIO_WRITE) 4579 dropobj = bp->b_bufobj; 4580 /* call optional completion function if requested */ 4581 if (bp->b_iodone != NULL) { 4582 biodone = bp->b_iodone; 4583 bp->b_iodone = NULL; 4584 (*biodone) (bp); 4585 if (dropobj) 4586 bufobj_wdrop(dropobj); 4587 return; 4588 } 4589 if (bp->b_flags & B_VMIO) { 4590 /* 4591 * Set B_CACHE if the op was a normal read and no error 4592 * occurred. B_CACHE is set for writes in the b*write() 4593 * routines. 4594 */ 4595 if (bp->b_iocmd == BIO_READ && 4596 !(bp->b_flags & (B_INVAL|B_NOCACHE)) && 4597 !(bp->b_ioflags & BIO_ERROR)) 4598 bp->b_flags |= B_CACHE; 4599 vfs_vmio_iodone(bp); 4600 } 4601 if (!LIST_EMPTY(&bp->b_dep)) 4602 buf_complete(bp); 4603 if ((bp->b_flags & B_CKHASH) != 0) { 4604 KASSERT(bp->b_iocmd == BIO_READ, 4605 ("bufdone: b_iocmd %d not BIO_READ", bp->b_iocmd)); 4606 KASSERT(buf_mapped(bp), ("bufdone: bp %p not mapped", bp)); 4607 (*bp->b_ckhashcalc)(bp); 4608 } 4609 /* 4610 * For asynchronous completions, release the buffer now. The brelse 4611 * will do a wakeup there if necessary - so no need to do a wakeup 4612 * here in the async case. The sync case always needs to do a wakeup. 4613 */ 4614 if (bp->b_flags & B_ASYNC) { 4615 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || 4616 (bp->b_ioflags & BIO_ERROR)) 4617 brelse(bp); 4618 else 4619 bqrelse(bp); 4620 } else 4621 bdone(bp); 4622 if (dropobj) 4623 bufobj_wdrop(dropobj); 4624 } 4625 4626 /* 4627 * This routine is called in lieu of iodone in the case of 4628 * incomplete I/O. This keeps the busy status for pages 4629 * consistent. 4630 */ 4631 void 4632 vfs_unbusy_pages(struct buf *bp) 4633 { 4634 int i; 4635 vm_object_t obj; 4636 vm_page_t m; 4637 4638 runningbufwakeup(bp); 4639 if (!(bp->b_flags & B_VMIO)) 4640 return; 4641 4642 obj = bp->b_bufobj->bo_object; 4643 for (i = 0; i < bp->b_npages; i++) { 4644 m = bp->b_pages[i]; 4645 if (m == bogus_page) { 4646 m = vm_page_relookup(obj, OFF_TO_IDX(bp->b_offset) + i); 4647 if (!m) 4648 panic("vfs_unbusy_pages: page missing\n"); 4649 bp->b_pages[i] = m; 4650 if (buf_mapped(bp)) { 4651 BUF_CHECK_MAPPED(bp); 4652 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4653 bp->b_pages, bp->b_npages); 4654 } else 4655 BUF_CHECK_UNMAPPED(bp); 4656 } 4657 vm_page_sunbusy(m); 4658 } 4659 vm_object_pip_wakeupn(obj, bp->b_npages); 4660 } 4661 4662 /* 4663 * vfs_page_set_valid: 4664 * 4665 * Set the valid bits in a page based on the supplied offset. The 4666 * range is restricted to the buffer's size. 4667 * 4668 * This routine is typically called after a read completes. 4669 */ 4670 static void 4671 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4672 { 4673 vm_ooffset_t eoff; 4674 4675 /* 4676 * Compute the end offset, eoff, such that [off, eoff) does not span a 4677 * page boundary and eoff is not greater than the end of the buffer. 4678 * The end of the buffer, in this case, is our file EOF, not the 4679 * allocation size of the buffer. 4680 */ 4681 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK; 4682 if (eoff > bp->b_offset + bp->b_bcount) 4683 eoff = bp->b_offset + bp->b_bcount; 4684 4685 /* 4686 * Set valid range. This is typically the entire buffer and thus the 4687 * entire page. 4688 */ 4689 if (eoff > off) 4690 vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off); 4691 } 4692 4693 /* 4694 * vfs_page_set_validclean: 4695 * 4696 * Set the valid bits and clear the dirty bits in a page based on the 4697 * supplied offset. The range is restricted to the buffer's size. 4698 */ 4699 static void 4700 vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4701 { 4702 vm_ooffset_t soff, eoff; 4703 4704 /* 4705 * Start and end offsets in buffer. eoff - soff may not cross a 4706 * page boundary or cross the end of the buffer. The end of the 4707 * buffer, in this case, is our file EOF, not the allocation size 4708 * of the buffer. 4709 */ 4710 soff = off; 4711 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4712 if (eoff > bp->b_offset + bp->b_bcount) 4713 eoff = bp->b_offset + bp->b_bcount; 4714 4715 /* 4716 * Set valid range. This is typically the entire buffer and thus the 4717 * entire page. 4718 */ 4719 if (eoff > soff) { 4720 vm_page_set_validclean( 4721 m, 4722 (vm_offset_t) (soff & PAGE_MASK), 4723 (vm_offset_t) (eoff - soff) 4724 ); 4725 } 4726 } 4727 4728 /* 4729 * Acquire a shared busy on all pages in the buf. 4730 */ 4731 void 4732 vfs_busy_pages_acquire(struct buf *bp) 4733 { 4734 int i; 4735 4736 for (i = 0; i < bp->b_npages; i++) 4737 vm_page_busy_acquire(bp->b_pages[i], VM_ALLOC_SBUSY); 4738 } 4739 4740 void 4741 vfs_busy_pages_release(struct buf *bp) 4742 { 4743 int i; 4744 4745 for (i = 0; i < bp->b_npages; i++) 4746 vm_page_sunbusy(bp->b_pages[i]); 4747 } 4748 4749 /* 4750 * This routine is called before a device strategy routine. 4751 * It is used to tell the VM system that paging I/O is in 4752 * progress, and treat the pages associated with the buffer 4753 * almost as being exclusive busy. Also the object paging_in_progress 4754 * flag is handled to make sure that the object doesn't become 4755 * inconsistent. 4756 * 4757 * Since I/O has not been initiated yet, certain buffer flags 4758 * such as BIO_ERROR or B_INVAL may be in an inconsistent state 4759 * and should be ignored. 4760 */ 4761 void 4762 vfs_busy_pages(struct buf *bp, int clear_modify) 4763 { 4764 vm_object_t obj; 4765 vm_ooffset_t foff; 4766 vm_page_t m; 4767 int i; 4768 bool bogus; 4769 4770 if (!(bp->b_flags & B_VMIO)) 4771 return; 4772 4773 obj = bp->b_bufobj->bo_object; 4774 foff = bp->b_offset; 4775 KASSERT(bp->b_offset != NOOFFSET, 4776 ("vfs_busy_pages: no buffer offset")); 4777 if ((bp->b_flags & B_CLUSTER) == 0) { 4778 vm_object_pip_add(obj, bp->b_npages); 4779 vfs_busy_pages_acquire(bp); 4780 } 4781 if (bp->b_bufsize != 0) 4782 vfs_setdirty_range(bp); 4783 bogus = false; 4784 for (i = 0; i < bp->b_npages; i++) { 4785 m = bp->b_pages[i]; 4786 vm_page_assert_sbusied(m); 4787 4788 /* 4789 * When readying a buffer for a read ( i.e 4790 * clear_modify == 0 ), it is important to do 4791 * bogus_page replacement for valid pages in 4792 * partially instantiated buffers. Partially 4793 * instantiated buffers can, in turn, occur when 4794 * reconstituting a buffer from its VM backing store 4795 * base. We only have to do this if B_CACHE is 4796 * clear ( which causes the I/O to occur in the 4797 * first place ). The replacement prevents the read 4798 * I/O from overwriting potentially dirty VM-backed 4799 * pages. XXX bogus page replacement is, uh, bogus. 4800 * It may not work properly with small-block devices. 4801 * We need to find a better way. 4802 */ 4803 if (clear_modify) { 4804 pmap_remove_write(m); 4805 vfs_page_set_validclean(bp, foff, m); 4806 } else if (vm_page_all_valid(m) && 4807 (bp->b_flags & B_CACHE) == 0) { 4808 bp->b_pages[i] = bogus_page; 4809 bogus = true; 4810 } 4811 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4812 } 4813 if (bogus && buf_mapped(bp)) { 4814 BUF_CHECK_MAPPED(bp); 4815 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4816 bp->b_pages, bp->b_npages); 4817 } 4818 } 4819 4820 /* 4821 * vfs_bio_set_valid: 4822 * 4823 * Set the range within the buffer to valid. The range is 4824 * relative to the beginning of the buffer, b_offset. Note that 4825 * b_offset itself may be offset from the beginning of the first 4826 * page. 4827 */ 4828 void 4829 vfs_bio_set_valid(struct buf *bp, int base, int size) 4830 { 4831 int i, n; 4832 vm_page_t m; 4833 4834 if (!(bp->b_flags & B_VMIO)) 4835 return; 4836 4837 /* 4838 * Fixup base to be relative to beginning of first page. 4839 * Set initial n to be the maximum number of bytes in the 4840 * first page that can be validated. 4841 */ 4842 base += (bp->b_offset & PAGE_MASK); 4843 n = PAGE_SIZE - (base & PAGE_MASK); 4844 4845 /* 4846 * Busy may not be strictly necessary here because the pages are 4847 * unlikely to be fully valid and the vnode lock will synchronize 4848 * their access via getpages. It is grabbed for consistency with 4849 * other page validation. 4850 */ 4851 vfs_busy_pages_acquire(bp); 4852 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4853 m = bp->b_pages[i]; 4854 if (n > size) 4855 n = size; 4856 vm_page_set_valid_range(m, base & PAGE_MASK, n); 4857 base += n; 4858 size -= n; 4859 n = PAGE_SIZE; 4860 } 4861 vfs_busy_pages_release(bp); 4862 } 4863 4864 /* 4865 * vfs_bio_clrbuf: 4866 * 4867 * If the specified buffer is a non-VMIO buffer, clear the entire 4868 * buffer. If the specified buffer is a VMIO buffer, clear and 4869 * validate only the previously invalid portions of the buffer. 4870 * This routine essentially fakes an I/O, so we need to clear 4871 * BIO_ERROR and B_INVAL. 4872 * 4873 * Note that while we only theoretically need to clear through b_bcount, 4874 * we go ahead and clear through b_bufsize. 4875 */ 4876 void 4877 vfs_bio_clrbuf(struct buf *bp) 4878 { 4879 int i, j, sa, ea, slide, zbits; 4880 vm_page_bits_t mask; 4881 4882 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) { 4883 clrbuf(bp); 4884 return; 4885 } 4886 bp->b_flags &= ~B_INVAL; 4887 bp->b_ioflags &= ~BIO_ERROR; 4888 vfs_busy_pages_acquire(bp); 4889 sa = bp->b_offset & PAGE_MASK; 4890 slide = 0; 4891 for (i = 0; i < bp->b_npages; i++, sa = 0) { 4892 slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize); 4893 ea = slide & PAGE_MASK; 4894 if (ea == 0) 4895 ea = PAGE_SIZE; 4896 if (bp->b_pages[i] == bogus_page) 4897 continue; 4898 j = sa / DEV_BSIZE; 4899 zbits = (sizeof(vm_page_bits_t) * NBBY) - 4900 (ea - sa) / DEV_BSIZE; 4901 mask = (VM_PAGE_BITS_ALL >> zbits) << j; 4902 if ((bp->b_pages[i]->valid & mask) == mask) 4903 continue; 4904 if ((bp->b_pages[i]->valid & mask) == 0) 4905 pmap_zero_page_area(bp->b_pages[i], sa, ea - sa); 4906 else { 4907 for (; sa < ea; sa += DEV_BSIZE, j++) { 4908 if ((bp->b_pages[i]->valid & (1 << j)) == 0) { 4909 pmap_zero_page_area(bp->b_pages[i], 4910 sa, DEV_BSIZE); 4911 } 4912 } 4913 } 4914 vm_page_set_valid_range(bp->b_pages[i], j * DEV_BSIZE, 4915 roundup2(ea - sa, DEV_BSIZE)); 4916 } 4917 vfs_busy_pages_release(bp); 4918 bp->b_resid = 0; 4919 } 4920 4921 void 4922 vfs_bio_bzero_buf(struct buf *bp, int base, int size) 4923 { 4924 vm_page_t m; 4925 int i, n; 4926 4927 if (buf_mapped(bp)) { 4928 BUF_CHECK_MAPPED(bp); 4929 bzero(bp->b_data + base, size); 4930 } else { 4931 BUF_CHECK_UNMAPPED(bp); 4932 n = PAGE_SIZE - (base & PAGE_MASK); 4933 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4934 m = bp->b_pages[i]; 4935 if (n > size) 4936 n = size; 4937 pmap_zero_page_area(m, base & PAGE_MASK, n); 4938 base += n; 4939 size -= n; 4940 n = PAGE_SIZE; 4941 } 4942 } 4943 } 4944 4945 /* 4946 * Update buffer flags based on I/O request parameters, optionally releasing the 4947 * buffer. If it's VMIO or direct I/O, the buffer pages are released to the VM, 4948 * where they may be placed on a page queue (VMIO) or freed immediately (direct 4949 * I/O). Otherwise the buffer is released to the cache. 4950 */ 4951 static void 4952 b_io_dismiss(struct buf *bp, int ioflag, bool release) 4953 { 4954 4955 KASSERT((ioflag & IO_NOREUSE) == 0 || (ioflag & IO_VMIO) != 0, 4956 ("buf %p non-VMIO noreuse", bp)); 4957 4958 if ((ioflag & IO_DIRECT) != 0) 4959 bp->b_flags |= B_DIRECT; 4960 if ((ioflag & IO_EXT) != 0) 4961 bp->b_xflags |= BX_ALTDATA; 4962 if ((ioflag & (IO_VMIO | IO_DIRECT)) != 0 && LIST_EMPTY(&bp->b_dep)) { 4963 bp->b_flags |= B_RELBUF; 4964 if ((ioflag & IO_NOREUSE) != 0) 4965 bp->b_flags |= B_NOREUSE; 4966 if (release) 4967 brelse(bp); 4968 } else if (release) 4969 bqrelse(bp); 4970 } 4971 4972 void 4973 vfs_bio_brelse(struct buf *bp, int ioflag) 4974 { 4975 4976 b_io_dismiss(bp, ioflag, true); 4977 } 4978 4979 void 4980 vfs_bio_set_flags(struct buf *bp, int ioflag) 4981 { 4982 4983 b_io_dismiss(bp, ioflag, false); 4984 } 4985 4986 /* 4987 * vm_hold_load_pages and vm_hold_free_pages get pages into 4988 * a buffers address space. The pages are anonymous and are 4989 * not associated with a file object. 4990 */ 4991 static void 4992 vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to) 4993 { 4994 vm_offset_t pg; 4995 vm_page_t p; 4996 int index; 4997 4998 BUF_CHECK_MAPPED(bp); 4999 5000 to = round_page(to); 5001 from = round_page(from); 5002 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 5003 MPASS((bp->b_flags & B_MAXPHYS) == 0); 5004 KASSERT(to - from <= maxbcachebuf, 5005 ("vm_hold_load_pages too large %p %#jx %#jx %u", 5006 bp, (uintmax_t)from, (uintmax_t)to, maxbcachebuf)); 5007 5008 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 5009 /* 5010 * note: must allocate system pages since blocking here 5011 * could interfere with paging I/O, no matter which 5012 * process we are. 5013 */ 5014 p = vm_page_alloc_noobj(VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | 5015 VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT) | VM_ALLOC_WAITOK); 5016 pmap_qenter(pg, &p, 1); 5017 bp->b_pages[index] = p; 5018 } 5019 bp->b_npages = index; 5020 } 5021 5022 /* Return pages associated with this buf to the vm system */ 5023 static void 5024 vm_hold_free_pages(struct buf *bp, int newbsize) 5025 { 5026 vm_offset_t from; 5027 vm_page_t p; 5028 int index, newnpages; 5029 5030 BUF_CHECK_MAPPED(bp); 5031 5032 from = round_page((vm_offset_t)bp->b_data + newbsize); 5033 newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 5034 if (bp->b_npages > newnpages) 5035 pmap_qremove(from, bp->b_npages - newnpages); 5036 for (index = newnpages; index < bp->b_npages; index++) { 5037 p = bp->b_pages[index]; 5038 bp->b_pages[index] = NULL; 5039 vm_page_unwire_noq(p); 5040 vm_page_free(p); 5041 } 5042 bp->b_npages = newnpages; 5043 } 5044 5045 /* 5046 * Map an IO request into kernel virtual address space. 5047 * 5048 * All requests are (re)mapped into kernel VA space. 5049 * Notice that we use b_bufsize for the size of the buffer 5050 * to be mapped. b_bcount might be modified by the driver. 5051 * 5052 * Note that even if the caller determines that the address space should 5053 * be valid, a race or a smaller-file mapped into a larger space may 5054 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST 5055 * check the return value. 5056 * 5057 * This function only works with pager buffers. 5058 */ 5059 int 5060 vmapbuf(struct buf *bp, void *uaddr, size_t len, int mapbuf) 5061 { 5062 vm_prot_t prot; 5063 int pidx; 5064 5065 MPASS((bp->b_flags & B_MAXPHYS) != 0); 5066 prot = VM_PROT_READ; 5067 if (bp->b_iocmd == BIO_READ) 5068 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 5069 pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 5070 (vm_offset_t)uaddr, len, prot, bp->b_pages, PBUF_PAGES); 5071 if (pidx < 0) 5072 return (-1); 5073 bp->b_bufsize = len; 5074 bp->b_npages = pidx; 5075 bp->b_offset = ((vm_offset_t)uaddr) & PAGE_MASK; 5076 if (mapbuf || !unmapped_buf_allowed) { 5077 pmap_qenter((vm_offset_t)bp->b_kvabase, bp->b_pages, pidx); 5078 bp->b_data = bp->b_kvabase + bp->b_offset; 5079 } else 5080 bp->b_data = unmapped_buf; 5081 return (0); 5082 } 5083 5084 /* 5085 * Free the io map PTEs associated with this IO operation. 5086 * We also invalidate the TLB entries and restore the original b_addr. 5087 * 5088 * This function only works with pager buffers. 5089 */ 5090 void 5091 vunmapbuf(struct buf *bp) 5092 { 5093 int npages; 5094 5095 npages = bp->b_npages; 5096 if (buf_mapped(bp)) 5097 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages); 5098 vm_page_unhold_pages(bp->b_pages, npages); 5099 5100 bp->b_data = unmapped_buf; 5101 } 5102 5103 void 5104 bdone(struct buf *bp) 5105 { 5106 struct mtx *mtxp; 5107 5108 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5109 mtx_lock(mtxp); 5110 bp->b_flags |= B_DONE; 5111 wakeup(bp); 5112 mtx_unlock(mtxp); 5113 } 5114 5115 void 5116 bwait(struct buf *bp, u_char pri, const char *wchan) 5117 { 5118 struct mtx *mtxp; 5119 5120 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5121 mtx_lock(mtxp); 5122 while ((bp->b_flags & B_DONE) == 0) 5123 msleep(bp, mtxp, pri, wchan, 0); 5124 mtx_unlock(mtxp); 5125 } 5126 5127 int 5128 bufsync(struct bufobj *bo, int waitfor) 5129 { 5130 5131 return (VOP_FSYNC(bo2vnode(bo), waitfor, curthread)); 5132 } 5133 5134 void 5135 bufstrategy(struct bufobj *bo, struct buf *bp) 5136 { 5137 int i __unused; 5138 struct vnode *vp; 5139 5140 vp = bp->b_vp; 5141 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy")); 5142 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 5143 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp)); 5144 i = VOP_STRATEGY(vp, bp); 5145 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp)); 5146 } 5147 5148 /* 5149 * Initialize a struct bufobj before use. Memory is assumed zero filled. 5150 */ 5151 void 5152 bufobj_init(struct bufobj *bo, void *private) 5153 { 5154 static volatile int bufobj_cleanq; 5155 5156 bo->bo_domain = 5157 atomic_fetchadd_int(&bufobj_cleanq, 1) % buf_domains; 5158 rw_init(BO_LOCKPTR(bo), "bufobj interlock"); 5159 bo->bo_private = private; 5160 TAILQ_INIT(&bo->bo_clean.bv_hd); 5161 pctrie_init(&bo->bo_clean.bv_root); 5162 TAILQ_INIT(&bo->bo_dirty.bv_hd); 5163 pctrie_init(&bo->bo_dirty.bv_root); 5164 } 5165 5166 void 5167 bufobj_wrefl(struct bufobj *bo) 5168 { 5169 5170 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5171 ASSERT_BO_WLOCKED(bo); 5172 bo->bo_numoutput++; 5173 } 5174 5175 void 5176 bufobj_wref(struct bufobj *bo) 5177 { 5178 5179 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5180 BO_LOCK(bo); 5181 bo->bo_numoutput++; 5182 BO_UNLOCK(bo); 5183 } 5184 5185 void 5186 bufobj_wdrop(struct bufobj *bo) 5187 { 5188 5189 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop")); 5190 BO_LOCK(bo); 5191 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count")); 5192 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) { 5193 bo->bo_flag &= ~BO_WWAIT; 5194 wakeup(&bo->bo_numoutput); 5195 } 5196 BO_UNLOCK(bo); 5197 } 5198 5199 int 5200 bufobj_wwait(struct bufobj *bo, int slpflag, int timeo) 5201 { 5202 int error; 5203 5204 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait")); 5205 ASSERT_BO_WLOCKED(bo); 5206 error = 0; 5207 while (bo->bo_numoutput) { 5208 bo->bo_flag |= BO_WWAIT; 5209 error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo), 5210 slpflag | (PRIBIO + 1), "bo_wwait", timeo); 5211 if (error) 5212 break; 5213 } 5214 return (error); 5215 } 5216 5217 /* 5218 * Set bio_data or bio_ma for struct bio from the struct buf. 5219 */ 5220 void 5221 bdata2bio(struct buf *bp, struct bio *bip) 5222 { 5223 5224 if (!buf_mapped(bp)) { 5225 KASSERT(unmapped_buf_allowed, ("unmapped")); 5226 bip->bio_ma = bp->b_pages; 5227 bip->bio_ma_n = bp->b_npages; 5228 bip->bio_data = unmapped_buf; 5229 bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK; 5230 bip->bio_flags |= BIO_UNMAPPED; 5231 KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) / 5232 PAGE_SIZE == bp->b_npages, 5233 ("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset, 5234 (long long)bip->bio_length, bip->bio_ma_n)); 5235 } else { 5236 bip->bio_data = bp->b_data; 5237 bip->bio_ma = NULL; 5238 } 5239 } 5240 5241 struct memdesc 5242 memdesc_bio(struct bio *bio) 5243 { 5244 if ((bio->bio_flags & BIO_VLIST) != 0) 5245 return (memdesc_vlist((struct bus_dma_segment *)bio->bio_data, 5246 bio->bio_ma_n)); 5247 5248 if ((bio->bio_flags & BIO_UNMAPPED) != 0) 5249 return (memdesc_vmpages(bio->bio_ma, bio->bio_bcount, 5250 bio->bio_ma_offset)); 5251 5252 return (memdesc_vaddr(bio->bio_data, bio->bio_bcount)); 5253 } 5254 5255 static int buf_pager_relbuf; 5256 SYSCTL_INT(_vfs, OID_AUTO, buf_pager_relbuf, CTLFLAG_RWTUN, 5257 &buf_pager_relbuf, 0, 5258 "Make buffer pager release buffers after reading"); 5259 5260 /* 5261 * The buffer pager. It uses buffer reads to validate pages. 5262 * 5263 * In contrast to the generic local pager from vm/vnode_pager.c, this 5264 * pager correctly and easily handles volumes where the underlying 5265 * device block size is greater than the machine page size. The 5266 * buffer cache transparently extends the requested page run to be 5267 * aligned at the block boundary, and does the necessary bogus page 5268 * replacements in the addends to avoid obliterating already valid 5269 * pages. 5270 * 5271 * The only non-trivial issue is that the exclusive busy state for 5272 * pages, which is assumed by the vm_pager_getpages() interface, is 5273 * incompatible with the VMIO buffer cache's desire to share-busy the 5274 * pages. This function performs a trivial downgrade of the pages' 5275 * state before reading buffers, and a less trivial upgrade from the 5276 * shared-busy to excl-busy state after the read. 5277 */ 5278 int 5279 vfs_bio_getpages(struct vnode *vp, vm_page_t *ma, int count, 5280 int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno, 5281 vbg_get_blksize_t get_blksize) 5282 { 5283 vm_page_t m; 5284 vm_object_t object; 5285 struct buf *bp; 5286 struct mount *mp; 5287 daddr_t lbn, lbnp; 5288 vm_ooffset_t la, lb, poff, poffe; 5289 long bo_bs, bsize; 5290 int br_flags, error, i, pgsin, pgsin_a, pgsin_b; 5291 bool redo, lpart; 5292 5293 object = vp->v_object; 5294 mp = vp->v_mount; 5295 error = 0; 5296 la = IDX_TO_OFF(ma[count - 1]->pindex); 5297 if (la >= object->un_pager.vnp.vnp_size) 5298 return (VM_PAGER_BAD); 5299 5300 /* 5301 * Change the meaning of la from where the last requested page starts 5302 * to where it ends, because that's the end of the requested region 5303 * and the start of the potential read-ahead region. 5304 */ 5305 la += PAGE_SIZE; 5306 lpart = la > object->un_pager.vnp.vnp_size; 5307 error = get_blksize(vp, get_lblkno(vp, IDX_TO_OFF(ma[0]->pindex)), 5308 &bo_bs); 5309 if (error != 0) 5310 return (VM_PAGER_ERROR); 5311 5312 /* 5313 * Calculate read-ahead, behind and total pages. 5314 */ 5315 pgsin = count; 5316 lb = IDX_TO_OFF(ma[0]->pindex); 5317 pgsin_b = OFF_TO_IDX(lb - rounddown2(lb, bo_bs)); 5318 pgsin += pgsin_b; 5319 if (rbehind != NULL) 5320 *rbehind = pgsin_b; 5321 pgsin_a = OFF_TO_IDX(roundup2(la, bo_bs) - la); 5322 if (la + IDX_TO_OFF(pgsin_a) >= object->un_pager.vnp.vnp_size) 5323 pgsin_a = OFF_TO_IDX(roundup2(object->un_pager.vnp.vnp_size, 5324 PAGE_SIZE) - la); 5325 pgsin += pgsin_a; 5326 if (rahead != NULL) 5327 *rahead = pgsin_a; 5328 VM_CNT_INC(v_vnodein); 5329 VM_CNT_ADD(v_vnodepgsin, pgsin); 5330 5331 br_flags = (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) 5332 != 0) ? GB_UNMAPPED : 0; 5333 again: 5334 for (i = 0; i < count; i++) { 5335 if (ma[i] != bogus_page) 5336 vm_page_busy_downgrade(ma[i]); 5337 } 5338 5339 lbnp = -1; 5340 for (i = 0; i < count; i++) { 5341 m = ma[i]; 5342 if (m == bogus_page) 5343 continue; 5344 5345 /* 5346 * Pages are shared busy and the object lock is not 5347 * owned, which together allow for the pages' 5348 * invalidation. The racy test for validity avoids 5349 * useless creation of the buffer for the most typical 5350 * case when invalidation is not used in redo or for 5351 * parallel read. The shared->excl upgrade loop at 5352 * the end of the function catches the race in a 5353 * reliable way (protected by the object lock). 5354 */ 5355 if (vm_page_all_valid(m)) 5356 continue; 5357 5358 poff = IDX_TO_OFF(m->pindex); 5359 poffe = MIN(poff + PAGE_SIZE, object->un_pager.vnp.vnp_size); 5360 for (; poff < poffe; poff += bsize) { 5361 lbn = get_lblkno(vp, poff); 5362 if (lbn == lbnp) 5363 goto next_page; 5364 lbnp = lbn; 5365 5366 error = get_blksize(vp, lbn, &bsize); 5367 if (error == 0) 5368 error = bread_gb(vp, lbn, bsize, 5369 curthread->td_ucred, br_flags, &bp); 5370 if (error != 0) 5371 goto end_pages; 5372 if (bp->b_rcred == curthread->td_ucred) { 5373 crfree(bp->b_rcred); 5374 bp->b_rcred = NOCRED; 5375 } 5376 if (LIST_EMPTY(&bp->b_dep)) { 5377 /* 5378 * Invalidation clears m->valid, but 5379 * may leave B_CACHE flag if the 5380 * buffer existed at the invalidation 5381 * time. In this case, recycle the 5382 * buffer to do real read on next 5383 * bread() after redo. 5384 * 5385 * Otherwise B_RELBUF is not strictly 5386 * necessary, enable to reduce buf 5387 * cache pressure. 5388 */ 5389 if (buf_pager_relbuf || 5390 !vm_page_all_valid(m)) 5391 bp->b_flags |= B_RELBUF; 5392 5393 bp->b_flags &= ~B_NOCACHE; 5394 brelse(bp); 5395 } else { 5396 bqrelse(bp); 5397 } 5398 } 5399 KASSERT(1 /* racy, enable for debugging */ || 5400 vm_page_all_valid(m) || i == count - 1, 5401 ("buf %d %p invalid", i, m)); 5402 if (i == count - 1 && lpart) { 5403 if (!vm_page_none_valid(m) && 5404 !vm_page_all_valid(m)) 5405 vm_page_zero_invalid(m, TRUE); 5406 } 5407 next_page:; 5408 } 5409 end_pages: 5410 5411 redo = false; 5412 for (i = 0; i < count; i++) { 5413 if (ma[i] == bogus_page) 5414 continue; 5415 if (vm_page_busy_tryupgrade(ma[i]) == 0) { 5416 vm_page_sunbusy(ma[i]); 5417 ma[i] = vm_page_grab_unlocked(object, ma[i]->pindex, 5418 VM_ALLOC_NORMAL); 5419 } 5420 5421 /* 5422 * Since the pages were only sbusy while neither the 5423 * buffer nor the object lock was held by us, or 5424 * reallocated while vm_page_grab() slept for busy 5425 * relinguish, they could have been invalidated. 5426 * Recheck the valid bits and re-read as needed. 5427 * 5428 * Note that the last page is made fully valid in the 5429 * read loop, and partial validity for the page at 5430 * index count - 1 could mean that the page was 5431 * invalidated or removed, so we must restart for 5432 * safety as well. 5433 */ 5434 if (!vm_page_all_valid(ma[i])) 5435 redo = true; 5436 } 5437 if (redo && error == 0) 5438 goto again; 5439 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 5440 } 5441 5442 #include "opt_ddb.h" 5443 #ifdef DDB 5444 #include <ddb/ddb.h> 5445 5446 /* DDB command to show buffer data */ 5447 DB_SHOW_COMMAND(buffer, db_show_buffer) 5448 { 5449 /* get args */ 5450 struct buf *bp = (struct buf *)addr; 5451 #ifdef FULL_BUF_TRACKING 5452 uint32_t i, j; 5453 #endif 5454 5455 if (!have_addr) { 5456 db_printf("usage: show buffer <addr>\n"); 5457 return; 5458 } 5459 5460 db_printf("buf at %p\n", bp); 5461 db_printf("b_flags = 0x%b, b_xflags=0x%b\n", 5462 (u_int)bp->b_flags, PRINT_BUF_FLAGS, 5463 (u_int)bp->b_xflags, PRINT_BUF_XFLAGS); 5464 db_printf("b_vflags=0x%b b_ioflags0x%b\n", 5465 (u_int)bp->b_vflags, PRINT_BUF_VFLAGS, 5466 (u_int)bp->b_ioflags, PRINT_BIO_FLAGS); 5467 db_printf( 5468 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n" 5469 "b_bufobj = (%p), b_data = %p\n, b_blkno = %jd, b_lblkno = %jd, " 5470 "b_vp = %p, b_dep = %p\n", 5471 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 5472 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno, 5473 (intmax_t)bp->b_lblkno, bp->b_vp, bp->b_dep.lh_first); 5474 db_printf("b_kvabase = %p, b_kvasize = %d\n", 5475 bp->b_kvabase, bp->b_kvasize); 5476 if (bp->b_npages) { 5477 int i; 5478 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 5479 for (i = 0; i < bp->b_npages; i++) { 5480 vm_page_t m; 5481 m = bp->b_pages[i]; 5482 if (m != NULL) 5483 db_printf("(%p, 0x%lx, 0x%lx)", m->object, 5484 (u_long)m->pindex, 5485 (u_long)VM_PAGE_TO_PHYS(m)); 5486 else 5487 db_printf("( ??? )"); 5488 if ((i + 1) < bp->b_npages) 5489 db_printf(","); 5490 } 5491 db_printf("\n"); 5492 } 5493 BUF_LOCKPRINTINFO(bp); 5494 #if defined(FULL_BUF_TRACKING) 5495 db_printf("b_io_tracking: b_io_tcnt = %u\n", bp->b_io_tcnt); 5496 5497 i = bp->b_io_tcnt % BUF_TRACKING_SIZE; 5498 for (j = 1; j <= BUF_TRACKING_SIZE; j++) { 5499 if (bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)] == NULL) 5500 continue; 5501 db_printf(" %2u: %s\n", j, 5502 bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)]); 5503 } 5504 #elif defined(BUF_TRACKING) 5505 db_printf("b_io_tracking: %s\n", bp->b_io_tracking); 5506 #endif 5507 db_printf(" "); 5508 } 5509 5510 DB_SHOW_COMMAND_FLAGS(bufqueues, bufqueues, DB_CMD_MEMSAFE) 5511 { 5512 struct bufdomain *bd; 5513 struct buf *bp; 5514 long total; 5515 int i, j, cnt; 5516 5517 db_printf("bqempty: %d\n", bqempty.bq_len); 5518 5519 for (i = 0; i < buf_domains; i++) { 5520 bd = &bdomain[i]; 5521 db_printf("Buf domain %d\n", i); 5522 db_printf("\tfreebufs\t%d\n", bd->bd_freebuffers); 5523 db_printf("\tlofreebufs\t%d\n", bd->bd_lofreebuffers); 5524 db_printf("\thifreebufs\t%d\n", bd->bd_hifreebuffers); 5525 db_printf("\n"); 5526 db_printf("\tbufspace\t%ld\n", bd->bd_bufspace); 5527 db_printf("\tmaxbufspace\t%ld\n", bd->bd_maxbufspace); 5528 db_printf("\thibufspace\t%ld\n", bd->bd_hibufspace); 5529 db_printf("\tlobufspace\t%ld\n", bd->bd_lobufspace); 5530 db_printf("\tbufspacethresh\t%ld\n", bd->bd_bufspacethresh); 5531 db_printf("\n"); 5532 db_printf("\tnumdirtybuffers\t%d\n", bd->bd_numdirtybuffers); 5533 db_printf("\tlodirtybuffers\t%d\n", bd->bd_lodirtybuffers); 5534 db_printf("\thidirtybuffers\t%d\n", bd->bd_hidirtybuffers); 5535 db_printf("\tdirtybufthresh\t%d\n", bd->bd_dirtybufthresh); 5536 db_printf("\n"); 5537 total = 0; 5538 TAILQ_FOREACH(bp, &bd->bd_cleanq->bq_queue, b_freelist) 5539 total += bp->b_bufsize; 5540 db_printf("\tcleanq count\t%d (%ld)\n", 5541 bd->bd_cleanq->bq_len, total); 5542 total = 0; 5543 TAILQ_FOREACH(bp, &bd->bd_dirtyq.bq_queue, b_freelist) 5544 total += bp->b_bufsize; 5545 db_printf("\tdirtyq count\t%d (%ld)\n", 5546 bd->bd_dirtyq.bq_len, total); 5547 db_printf("\twakeup\t\t%d\n", bd->bd_wanted); 5548 db_printf("\tlim\t\t%d\n", bd->bd_lim); 5549 db_printf("\tCPU "); 5550 for (j = 0; j <= mp_maxid; j++) 5551 db_printf("%d, ", bd->bd_subq[j].bq_len); 5552 db_printf("\n"); 5553 cnt = 0; 5554 total = 0; 5555 for (j = 0; j < nbuf; j++) { 5556 bp = nbufp(j); 5557 if (bp->b_domain == i && BUF_ISLOCKED(bp)) { 5558 cnt++; 5559 total += bp->b_bufsize; 5560 } 5561 } 5562 db_printf("\tLocked buffers: %d space %ld\n", cnt, total); 5563 cnt = 0; 5564 total = 0; 5565 for (j = 0; j < nbuf; j++) { 5566 bp = nbufp(j); 5567 if (bp->b_domain == i) { 5568 cnt++; 5569 total += bp->b_bufsize; 5570 } 5571 } 5572 db_printf("\tTotal buffers: %d space %ld\n", cnt, total); 5573 } 5574 } 5575 5576 DB_SHOW_COMMAND_FLAGS(lockedbufs, lockedbufs, DB_CMD_MEMSAFE) 5577 { 5578 struct buf *bp; 5579 int i; 5580 5581 for (i = 0; i < nbuf; i++) { 5582 bp = nbufp(i); 5583 if (BUF_ISLOCKED(bp)) { 5584 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5585 db_printf("\n"); 5586 if (db_pager_quit) 5587 break; 5588 } 5589 } 5590 } 5591 5592 DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs) 5593 { 5594 struct vnode *vp; 5595 struct buf *bp; 5596 5597 if (!have_addr) { 5598 db_printf("usage: show vnodebufs <addr>\n"); 5599 return; 5600 } 5601 vp = (struct vnode *)addr; 5602 db_printf("Clean buffers:\n"); 5603 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) { 5604 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5605 db_printf("\n"); 5606 } 5607 db_printf("Dirty buffers:\n"); 5608 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) { 5609 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5610 db_printf("\n"); 5611 } 5612 } 5613 5614 DB_COMMAND_FLAGS(countfreebufs, db_coundfreebufs, DB_CMD_MEMSAFE) 5615 { 5616 struct buf *bp; 5617 int i, used = 0, nfree = 0; 5618 5619 if (have_addr) { 5620 db_printf("usage: countfreebufs\n"); 5621 return; 5622 } 5623 5624 for (i = 0; i < nbuf; i++) { 5625 bp = nbufp(i); 5626 if (bp->b_qindex == QUEUE_EMPTY) 5627 nfree++; 5628 else 5629 used++; 5630 } 5631 5632 db_printf("Counted %d free, %d used (%d tot)\n", nfree, used, 5633 nfree + used); 5634 db_printf("numfreebuffers is %d\n", numfreebuffers); 5635 } 5636 #endif /* DDB */ 5637