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 upper limit for hirunningspace was chosen arbitrarily and 1257 * may need further tuning. It corresponds to 128 outstanding write IO 1258 * requests, which fits with many RAID controllers' tagged queuing 1259 * limits. 1260 * 1261 * The lower 1 MiB limit is the historical upper limit for 1262 * hirunningspace. 1263 */ 1264 hirunningspace = lmax(lmin(roundup(hibufspace / 64, maxbcachebuf), 1265 128 * maxphys), 1024 * 1024); 1266 lorunningspace = roundup((hirunningspace * 2) / 3, maxbcachebuf); 1267 1268 /* 1269 * Limit the amount of malloc memory since it is wired permanently into 1270 * the kernel space. Even though this is accounted for in the buffer 1271 * allocation, we don't want the malloced region to grow uncontrolled. 1272 * The malloc scheme improves memory utilization significantly on 1273 * average (small) directories. 1274 */ 1275 maxbufmallocspace = hibufspace / 20; 1276 1277 /* 1278 * Reduce the chance of a deadlock occurring by limiting the number 1279 * of delayed-write dirty buffers we allow to stack up. 1280 */ 1281 hidirtybuffers = nbuf / 4 + 20; 1282 dirtybufthresh = hidirtybuffers * 9 / 10; 1283 /* 1284 * To support extreme low-memory systems, make sure hidirtybuffers 1285 * cannot eat up all available buffer space. This occurs when our 1286 * minimum cannot be met. We try to size hidirtybuffers to 3/4 our 1287 * buffer space assuming BKVASIZE'd buffers. 1288 */ 1289 while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) { 1290 hidirtybuffers >>= 1; 1291 } 1292 lodirtybuffers = hidirtybuffers / 2; 1293 1294 /* 1295 * lofreebuffers should be sufficient to avoid stalling waiting on 1296 * buf headers under heavy utilization. The bufs in per-cpu caches 1297 * are counted as free but will be unavailable to threads executing 1298 * on other cpus. 1299 * 1300 * hifreebuffers is the free target for the bufspace daemon. This 1301 * should be set appropriately to limit work per-iteration. 1302 */ 1303 lofreebuffers = MIN((nbuf / 25) + (20 * mp_ncpus), 128 * mp_ncpus); 1304 hifreebuffers = (3 * lofreebuffers) / 2; 1305 numfreebuffers = nbuf; 1306 1307 /* Setup the kva and free list allocators. */ 1308 vmem_set_reclaim(buffer_arena, bufkva_reclaim); 1309 buf_zone = uma_zcache_create("buf free cache", 1310 sizeof(struct buf) + sizeof(vm_page_t) * atop(maxbcachebuf), 1311 NULL, NULL, NULL, NULL, buf_import, buf_release, NULL, 0); 1312 1313 /* 1314 * Size the clean queue according to the amount of buffer space. 1315 * One queue per-256mb up to the max. More queues gives better 1316 * concurrency but less accurate LRU. 1317 */ 1318 buf_domains = MIN(howmany(maxbufspace, 256*1024*1024), BUF_DOMAINS); 1319 for (i = 0 ; i < buf_domains; i++) { 1320 struct bufdomain *bd; 1321 1322 bd = &bdomain[i]; 1323 bd_init(bd); 1324 bd->bd_freebuffers = nbuf / buf_domains; 1325 bd->bd_hifreebuffers = hifreebuffers / buf_domains; 1326 bd->bd_lofreebuffers = lofreebuffers / buf_domains; 1327 bd->bd_bufspace = 0; 1328 bd->bd_maxbufspace = maxbufspace / buf_domains; 1329 bd->bd_hibufspace = hibufspace / buf_domains; 1330 bd->bd_lobufspace = lobufspace / buf_domains; 1331 bd->bd_bufspacethresh = bufspacethresh / buf_domains; 1332 bd->bd_numdirtybuffers = 0; 1333 bd->bd_hidirtybuffers = hidirtybuffers / buf_domains; 1334 bd->bd_lodirtybuffers = lodirtybuffers / buf_domains; 1335 bd->bd_dirtybufthresh = dirtybufthresh / buf_domains; 1336 /* Don't allow more than 2% of bufs in the per-cpu caches. */ 1337 bd->bd_lim = nbuf / buf_domains / 50 / mp_ncpus; 1338 } 1339 getnewbufcalls = counter_u64_alloc(M_WAITOK); 1340 getnewbufrestarts = counter_u64_alloc(M_WAITOK); 1341 mappingrestarts = counter_u64_alloc(M_WAITOK); 1342 numbufallocfails = counter_u64_alloc(M_WAITOK); 1343 notbufdflushes = counter_u64_alloc(M_WAITOK); 1344 buffreekvacnt = counter_u64_alloc(M_WAITOK); 1345 bufdefragcnt = counter_u64_alloc(M_WAITOK); 1346 bufkvaspace = counter_u64_alloc(M_WAITOK); 1347 TSEXIT(); 1348 } 1349 1350 #ifdef INVARIANTS 1351 static inline void 1352 vfs_buf_check_mapped(struct buf *bp) 1353 { 1354 1355 KASSERT(bp->b_kvabase != unmapped_buf, 1356 ("mapped buf: b_kvabase was not updated %p", bp)); 1357 KASSERT(bp->b_data != unmapped_buf, 1358 ("mapped buf: b_data was not updated %p", bp)); 1359 KASSERT(bp->b_data < unmapped_buf || bp->b_data >= unmapped_buf + 1360 maxphys, ("b_data + b_offset unmapped %p", bp)); 1361 } 1362 1363 static inline void 1364 vfs_buf_check_unmapped(struct buf *bp) 1365 { 1366 1367 KASSERT(bp->b_data == unmapped_buf, 1368 ("unmapped buf: corrupted b_data %p", bp)); 1369 } 1370 1371 #define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp) 1372 #define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp) 1373 #else 1374 #define BUF_CHECK_MAPPED(bp) do {} while (0) 1375 #define BUF_CHECK_UNMAPPED(bp) do {} while (0) 1376 #endif 1377 1378 static int 1379 isbufbusy(struct buf *bp) 1380 { 1381 if (((bp->b_flags & B_INVAL) == 0 && BUF_ISLOCKED(bp)) || 1382 ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)) 1383 return (1); 1384 return (0); 1385 } 1386 1387 /* 1388 * Shutdown the system cleanly to prepare for reboot, halt, or power off. 1389 */ 1390 void 1391 bufshutdown(int show_busybufs) 1392 { 1393 static int first_buf_printf = 1; 1394 struct buf *bp; 1395 int i, iter, nbusy, pbusy; 1396 #ifndef PREEMPTION 1397 int subiter; 1398 #endif 1399 1400 /* 1401 * Sync filesystems for shutdown 1402 */ 1403 wdog_kern_pat(WD_LASTVAL); 1404 kern_sync(curthread); 1405 1406 /* 1407 * With soft updates, some buffers that are 1408 * written will be remarked as dirty until other 1409 * buffers are written. 1410 */ 1411 for (iter = pbusy = 0; iter < 20; iter++) { 1412 nbusy = 0; 1413 for (i = nbuf - 1; i >= 0; i--) { 1414 bp = nbufp(i); 1415 if (isbufbusy(bp)) 1416 nbusy++; 1417 } 1418 if (nbusy == 0) { 1419 if (first_buf_printf) 1420 printf("All buffers synced."); 1421 break; 1422 } 1423 if (first_buf_printf) { 1424 printf("Syncing disks, buffers remaining... "); 1425 first_buf_printf = 0; 1426 } 1427 printf("%d ", nbusy); 1428 if (nbusy < pbusy) 1429 iter = 0; 1430 pbusy = nbusy; 1431 1432 wdog_kern_pat(WD_LASTVAL); 1433 kern_sync(curthread); 1434 1435 #ifdef PREEMPTION 1436 /* 1437 * Spin for a while to allow interrupt threads to run. 1438 */ 1439 DELAY(50000 * iter); 1440 #else 1441 /* 1442 * Context switch several times to allow interrupt 1443 * threads to run. 1444 */ 1445 for (subiter = 0; subiter < 50 * iter; subiter++) { 1446 sched_relinquish(curthread); 1447 DELAY(1000); 1448 } 1449 #endif 1450 } 1451 printf("\n"); 1452 /* 1453 * Count only busy local buffers to prevent forcing 1454 * a fsck if we're just a client of a wedged NFS server 1455 */ 1456 nbusy = 0; 1457 for (i = nbuf - 1; i >= 0; i--) { 1458 bp = nbufp(i); 1459 if (isbufbusy(bp)) { 1460 #if 0 1461 /* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */ 1462 if (bp->b_dev == NULL) { 1463 TAILQ_REMOVE(&mountlist, 1464 bp->b_vp->v_mount, mnt_list); 1465 continue; 1466 } 1467 #endif 1468 nbusy++; 1469 if (show_busybufs > 0) { 1470 printf( 1471 "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:", 1472 nbusy, bp, bp->b_vp, bp->b_flags, 1473 (intmax_t)bp->b_blkno, 1474 (intmax_t)bp->b_lblkno); 1475 BUF_LOCKPRINTINFO(bp); 1476 if (show_busybufs > 1) 1477 vn_printf(bp->b_vp, 1478 "vnode content: "); 1479 } 1480 } 1481 } 1482 if (nbusy) { 1483 /* 1484 * Failed to sync all blocks. Indicate this and don't 1485 * unmount filesystems (thus forcing an fsck on reboot). 1486 */ 1487 BOOTTRACE("shutdown failed to sync buffers"); 1488 printf("Giving up on %d buffers\n", nbusy); 1489 DELAY(5000000); /* 5 seconds */ 1490 swapoff_all(); 1491 } else { 1492 BOOTTRACE("shutdown sync complete"); 1493 if (!first_buf_printf) 1494 printf("Final sync complete\n"); 1495 1496 /* 1497 * Unmount filesystems and perform swapoff, to quiesce 1498 * the system as much as possible. In particular, no 1499 * I/O should be initiated from top levels since it 1500 * might be abruptly terminated by reset, or otherwise 1501 * erronously handled because other parts of the 1502 * system are disabled. 1503 * 1504 * Swapoff before unmount, because file-backed swap is 1505 * non-operational after unmount of the underlying 1506 * filesystem. 1507 */ 1508 if (!KERNEL_PANICKED()) { 1509 swapoff_all(); 1510 vfs_unmountall(); 1511 } 1512 BOOTTRACE("shutdown unmounted all filesystems"); 1513 } 1514 DELAY(100000); /* wait for console output to finish */ 1515 } 1516 1517 static void 1518 bpmap_qenter(struct buf *bp) 1519 { 1520 1521 BUF_CHECK_MAPPED(bp); 1522 1523 /* 1524 * bp->b_data is relative to bp->b_offset, but 1525 * bp->b_offset may be offset into the first page. 1526 */ 1527 bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data); 1528 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 1529 bp->b_data = (caddr_t)((vm_offset_t)bp->b_data | 1530 (vm_offset_t)(bp->b_offset & PAGE_MASK)); 1531 } 1532 1533 static inline struct bufdomain * 1534 bufdomain(struct buf *bp) 1535 { 1536 1537 return (&bdomain[bp->b_domain]); 1538 } 1539 1540 static struct bufqueue * 1541 bufqueue(struct buf *bp) 1542 { 1543 1544 switch (bp->b_qindex) { 1545 case QUEUE_NONE: 1546 /* FALLTHROUGH */ 1547 case QUEUE_SENTINEL: 1548 return (NULL); 1549 case QUEUE_EMPTY: 1550 return (&bqempty); 1551 case QUEUE_DIRTY: 1552 return (&bufdomain(bp)->bd_dirtyq); 1553 case QUEUE_CLEAN: 1554 return (&bufdomain(bp)->bd_subq[bp->b_subqueue]); 1555 default: 1556 break; 1557 } 1558 panic("bufqueue(%p): Unhandled type %d\n", bp, bp->b_qindex); 1559 } 1560 1561 /* 1562 * Return the locked bufqueue that bp is a member of. 1563 */ 1564 static struct bufqueue * 1565 bufqueue_acquire(struct buf *bp) 1566 { 1567 struct bufqueue *bq, *nbq; 1568 1569 /* 1570 * bp can be pushed from a per-cpu queue to the 1571 * cleanq while we're waiting on the lock. Retry 1572 * if the queues don't match. 1573 */ 1574 bq = bufqueue(bp); 1575 BQ_LOCK(bq); 1576 for (;;) { 1577 nbq = bufqueue(bp); 1578 if (bq == nbq) 1579 break; 1580 BQ_UNLOCK(bq); 1581 BQ_LOCK(nbq); 1582 bq = nbq; 1583 } 1584 return (bq); 1585 } 1586 1587 /* 1588 * binsfree: 1589 * 1590 * Insert the buffer into the appropriate free list. Requires a 1591 * locked buffer on entry and buffer is unlocked before return. 1592 */ 1593 static void 1594 binsfree(struct buf *bp, int qindex) 1595 { 1596 struct bufdomain *bd; 1597 struct bufqueue *bq; 1598 1599 KASSERT(qindex == QUEUE_CLEAN || qindex == QUEUE_DIRTY, 1600 ("binsfree: Invalid qindex %d", qindex)); 1601 BUF_ASSERT_XLOCKED(bp); 1602 1603 /* 1604 * Handle delayed bremfree() processing. 1605 */ 1606 if (bp->b_flags & B_REMFREE) { 1607 if (bp->b_qindex == qindex) { 1608 bp->b_flags |= B_REUSE; 1609 bp->b_flags &= ~B_REMFREE; 1610 BUF_UNLOCK(bp); 1611 return; 1612 } 1613 bq = bufqueue_acquire(bp); 1614 bq_remove(bq, bp); 1615 BQ_UNLOCK(bq); 1616 } 1617 bd = bufdomain(bp); 1618 if (qindex == QUEUE_CLEAN) { 1619 if (bd->bd_lim != 0) 1620 bq = &bd->bd_subq[PCPU_GET(cpuid)]; 1621 else 1622 bq = bd->bd_cleanq; 1623 } else 1624 bq = &bd->bd_dirtyq; 1625 bq_insert(bq, bp, true); 1626 } 1627 1628 /* 1629 * buf_free: 1630 * 1631 * Free a buffer to the buf zone once it no longer has valid contents. 1632 */ 1633 static void 1634 buf_free(struct buf *bp) 1635 { 1636 1637 if (bp->b_flags & B_REMFREE) 1638 bremfreef(bp); 1639 if (bp->b_vflags & BV_BKGRDINPROG) 1640 panic("losing buffer 1"); 1641 if (bp->b_rcred != NOCRED) { 1642 crfree(bp->b_rcred); 1643 bp->b_rcred = NOCRED; 1644 } 1645 if (bp->b_wcred != NOCRED) { 1646 crfree(bp->b_wcred); 1647 bp->b_wcred = NOCRED; 1648 } 1649 if (!LIST_EMPTY(&bp->b_dep)) 1650 buf_deallocate(bp); 1651 bufkva_free(bp); 1652 atomic_add_int(&bufdomain(bp)->bd_freebuffers, 1); 1653 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1654 BUF_UNLOCK(bp); 1655 uma_zfree(buf_zone, bp); 1656 } 1657 1658 /* 1659 * buf_import: 1660 * 1661 * Import bufs into the uma cache from the buf list. The system still 1662 * expects a static array of bufs and much of the synchronization 1663 * around bufs assumes type stable storage. As a result, UMA is used 1664 * only as a per-cpu cache of bufs still maintained on a global list. 1665 */ 1666 static int 1667 buf_import(void *arg, void **store, int cnt, int domain, int flags) 1668 { 1669 struct buf *bp; 1670 int i; 1671 1672 BQ_LOCK(&bqempty); 1673 for (i = 0; i < cnt; i++) { 1674 bp = TAILQ_FIRST(&bqempty.bq_queue); 1675 if (bp == NULL) 1676 break; 1677 bq_remove(&bqempty, bp); 1678 store[i] = bp; 1679 } 1680 BQ_UNLOCK(&bqempty); 1681 1682 return (i); 1683 } 1684 1685 /* 1686 * buf_release: 1687 * 1688 * Release bufs from the uma cache back to the buffer queues. 1689 */ 1690 static void 1691 buf_release(void *arg, void **store, int cnt) 1692 { 1693 struct bufqueue *bq; 1694 struct buf *bp; 1695 int i; 1696 1697 bq = &bqempty; 1698 BQ_LOCK(bq); 1699 for (i = 0; i < cnt; i++) { 1700 bp = store[i]; 1701 /* Inline bq_insert() to batch locking. */ 1702 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1703 bp->b_flags &= ~(B_AGE | B_REUSE); 1704 bq->bq_len++; 1705 bp->b_qindex = bq->bq_index; 1706 } 1707 BQ_UNLOCK(bq); 1708 } 1709 1710 /* 1711 * buf_alloc: 1712 * 1713 * Allocate an empty buffer header. 1714 */ 1715 static struct buf * 1716 buf_alloc(struct bufdomain *bd) 1717 { 1718 struct buf *bp; 1719 int freebufs, error; 1720 1721 /* 1722 * We can only run out of bufs in the buf zone if the average buf 1723 * is less than BKVASIZE. In this case the actual wait/block will 1724 * come from buf_reycle() failing to flush one of these small bufs. 1725 */ 1726 bp = NULL; 1727 freebufs = atomic_fetchadd_int(&bd->bd_freebuffers, -1); 1728 if (freebufs > 0) 1729 bp = uma_zalloc(buf_zone, M_NOWAIT); 1730 if (bp == NULL) { 1731 atomic_add_int(&bd->bd_freebuffers, 1); 1732 bufspace_daemon_wakeup(bd); 1733 counter_u64_add(numbufallocfails, 1); 1734 return (NULL); 1735 } 1736 /* 1737 * Wake-up the bufspace daemon on transition below threshold. 1738 */ 1739 if (freebufs == bd->bd_lofreebuffers) 1740 bufspace_daemon_wakeup(bd); 1741 1742 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL); 1743 KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, 1744 error)); 1745 (void)error; 1746 1747 KASSERT(bp->b_vp == NULL, 1748 ("bp: %p still has vnode %p.", bp, bp->b_vp)); 1749 KASSERT((bp->b_flags & (B_DELWRI | B_NOREUSE)) == 0, 1750 ("invalid buffer %p flags %#x", bp, bp->b_flags)); 1751 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0, 1752 ("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags)); 1753 KASSERT(bp->b_npages == 0, 1754 ("bp: %p still has %d vm pages\n", bp, bp->b_npages)); 1755 KASSERT(bp->b_kvasize == 0, ("bp: %p still has kva\n", bp)); 1756 KASSERT(bp->b_bufsize == 0, ("bp: %p still has bufspace\n", bp)); 1757 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1758 1759 bp->b_domain = BD_DOMAIN(bd); 1760 bp->b_flags = 0; 1761 bp->b_ioflags = 0; 1762 bp->b_xflags = 0; 1763 bp->b_vflags = 0; 1764 bp->b_vp = NULL; 1765 bp->b_blkno = bp->b_lblkno = 0; 1766 bp->b_offset = NOOFFSET; 1767 bp->b_iodone = 0; 1768 bp->b_error = 0; 1769 bp->b_resid = 0; 1770 bp->b_bcount = 0; 1771 bp->b_npages = 0; 1772 bp->b_dirtyoff = bp->b_dirtyend = 0; 1773 bp->b_bufobj = NULL; 1774 bp->b_data = bp->b_kvabase = unmapped_buf; 1775 bp->b_fsprivate1 = NULL; 1776 bp->b_fsprivate2 = NULL; 1777 bp->b_fsprivate3 = NULL; 1778 LIST_INIT(&bp->b_dep); 1779 1780 return (bp); 1781 } 1782 1783 /* 1784 * buf_recycle: 1785 * 1786 * Free a buffer from the given bufqueue. kva controls whether the 1787 * freed buf must own some kva resources. This is used for 1788 * defragmenting. 1789 */ 1790 static int 1791 buf_recycle(struct bufdomain *bd, bool kva) 1792 { 1793 struct bufqueue *bq; 1794 struct buf *bp, *nbp; 1795 1796 if (kva) 1797 counter_u64_add(bufdefragcnt, 1); 1798 nbp = NULL; 1799 bq = bd->bd_cleanq; 1800 BQ_LOCK(bq); 1801 KASSERT(BQ_LOCKPTR(bq) == BD_LOCKPTR(bd), 1802 ("buf_recycle: Locks don't match")); 1803 nbp = TAILQ_FIRST(&bq->bq_queue); 1804 1805 /* 1806 * Run scan, possibly freeing data and/or kva mappings on the fly 1807 * depending. 1808 */ 1809 while ((bp = nbp) != NULL) { 1810 /* 1811 * Calculate next bp (we can only use it if we do not 1812 * release the bqlock). 1813 */ 1814 nbp = TAILQ_NEXT(bp, b_freelist); 1815 1816 /* 1817 * If we are defragging then we need a buffer with 1818 * some kva to reclaim. 1819 */ 1820 if (kva && bp->b_kvasize == 0) 1821 continue; 1822 1823 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 1824 continue; 1825 1826 /* 1827 * Implement a second chance algorithm for frequently 1828 * accessed buffers. 1829 */ 1830 if ((bp->b_flags & B_REUSE) != 0) { 1831 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1832 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1833 bp->b_flags &= ~B_REUSE; 1834 BUF_UNLOCK(bp); 1835 continue; 1836 } 1837 1838 /* 1839 * Skip buffers with background writes in progress. 1840 */ 1841 if ((bp->b_vflags & BV_BKGRDINPROG) != 0) { 1842 BUF_UNLOCK(bp); 1843 continue; 1844 } 1845 1846 KASSERT(bp->b_qindex == QUEUE_CLEAN, 1847 ("buf_recycle: inconsistent queue %d bp %p", 1848 bp->b_qindex, bp)); 1849 KASSERT(bp->b_domain == BD_DOMAIN(bd), 1850 ("getnewbuf: queue domain %d doesn't match request %d", 1851 bp->b_domain, (int)BD_DOMAIN(bd))); 1852 /* 1853 * NOTE: nbp is now entirely invalid. We can only restart 1854 * the scan from this point on. 1855 */ 1856 bq_remove(bq, bp); 1857 BQ_UNLOCK(bq); 1858 1859 /* 1860 * Requeue the background write buffer with error and 1861 * restart the scan. 1862 */ 1863 if ((bp->b_vflags & BV_BKGRDERR) != 0) { 1864 bqrelse(bp); 1865 BQ_LOCK(bq); 1866 nbp = TAILQ_FIRST(&bq->bq_queue); 1867 continue; 1868 } 1869 bp->b_flags |= B_INVAL; 1870 brelse(bp); 1871 return (0); 1872 } 1873 bd->bd_wanted = 1; 1874 BQ_UNLOCK(bq); 1875 1876 return (ENOBUFS); 1877 } 1878 1879 /* 1880 * bremfree: 1881 * 1882 * Mark the buffer for removal from the appropriate free list. 1883 * 1884 */ 1885 void 1886 bremfree(struct buf *bp) 1887 { 1888 1889 CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1890 KASSERT((bp->b_flags & B_REMFREE) == 0, 1891 ("bremfree: buffer %p already marked for delayed removal.", bp)); 1892 KASSERT(bp->b_qindex != QUEUE_NONE, 1893 ("bremfree: buffer %p not on a queue.", bp)); 1894 BUF_ASSERT_XLOCKED(bp); 1895 1896 bp->b_flags |= B_REMFREE; 1897 } 1898 1899 /* 1900 * bremfreef: 1901 * 1902 * Force an immediate removal from a free list. Used only in nfs when 1903 * it abuses the b_freelist pointer. 1904 */ 1905 void 1906 bremfreef(struct buf *bp) 1907 { 1908 struct bufqueue *bq; 1909 1910 bq = bufqueue_acquire(bp); 1911 bq_remove(bq, bp); 1912 BQ_UNLOCK(bq); 1913 } 1914 1915 static void 1916 bq_init(struct bufqueue *bq, int qindex, int subqueue, const char *lockname) 1917 { 1918 1919 mtx_init(&bq->bq_lock, lockname, NULL, MTX_DEF); 1920 TAILQ_INIT(&bq->bq_queue); 1921 bq->bq_len = 0; 1922 bq->bq_index = qindex; 1923 bq->bq_subqueue = subqueue; 1924 } 1925 1926 static void 1927 bd_init(struct bufdomain *bd) 1928 { 1929 int i; 1930 1931 /* Per-CPU clean buf queues, plus one global queue. */ 1932 bd->bd_subq = mallocarray(mp_maxid + 2, sizeof(struct bufqueue), 1933 M_BIOBUF, M_WAITOK | M_ZERO); 1934 bd->bd_cleanq = &bd->bd_subq[mp_maxid + 1]; 1935 bq_init(bd->bd_cleanq, QUEUE_CLEAN, mp_maxid + 1, "bufq clean lock"); 1936 bq_init(&bd->bd_dirtyq, QUEUE_DIRTY, -1, "bufq dirty lock"); 1937 for (i = 0; i <= mp_maxid; i++) 1938 bq_init(&bd->bd_subq[i], QUEUE_CLEAN, i, 1939 "bufq clean subqueue lock"); 1940 mtx_init(&bd->bd_run_lock, "bufspace daemon run lock", NULL, MTX_DEF); 1941 } 1942 1943 /* 1944 * bq_remove: 1945 * 1946 * Removes a buffer from the free list, must be called with the 1947 * correct qlock held. 1948 */ 1949 static void 1950 bq_remove(struct bufqueue *bq, struct buf *bp) 1951 { 1952 1953 CTR3(KTR_BUF, "bq_remove(%p) vp %p flags %X", 1954 bp, bp->b_vp, bp->b_flags); 1955 KASSERT(bp->b_qindex != QUEUE_NONE, 1956 ("bq_remove: buffer %p not on a queue.", bp)); 1957 KASSERT(bufqueue(bp) == bq, 1958 ("bq_remove: Remove buffer %p from wrong queue.", bp)); 1959 1960 BQ_ASSERT_LOCKED(bq); 1961 if (bp->b_qindex != QUEUE_EMPTY) { 1962 BUF_ASSERT_XLOCKED(bp); 1963 } 1964 KASSERT(bq->bq_len >= 1, 1965 ("queue %d underflow", bp->b_qindex)); 1966 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1967 bq->bq_len--; 1968 bp->b_qindex = QUEUE_NONE; 1969 bp->b_flags &= ~(B_REMFREE | B_REUSE); 1970 } 1971 1972 static void 1973 bd_flush(struct bufdomain *bd, struct bufqueue *bq) 1974 { 1975 struct buf *bp; 1976 1977 BQ_ASSERT_LOCKED(bq); 1978 if (bq != bd->bd_cleanq) { 1979 BD_LOCK(bd); 1980 while ((bp = TAILQ_FIRST(&bq->bq_queue)) != NULL) { 1981 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1982 TAILQ_INSERT_TAIL(&bd->bd_cleanq->bq_queue, bp, 1983 b_freelist); 1984 bp->b_subqueue = bd->bd_cleanq->bq_subqueue; 1985 } 1986 bd->bd_cleanq->bq_len += bq->bq_len; 1987 bq->bq_len = 0; 1988 } 1989 if (bd->bd_wanted) { 1990 bd->bd_wanted = 0; 1991 wakeup(&bd->bd_wanted); 1992 } 1993 if (bq != bd->bd_cleanq) 1994 BD_UNLOCK(bd); 1995 } 1996 1997 static int 1998 bd_flushall(struct bufdomain *bd) 1999 { 2000 struct bufqueue *bq; 2001 int flushed; 2002 int i; 2003 2004 if (bd->bd_lim == 0) 2005 return (0); 2006 flushed = 0; 2007 for (i = 0; i <= mp_maxid; i++) { 2008 bq = &bd->bd_subq[i]; 2009 if (bq->bq_len == 0) 2010 continue; 2011 BQ_LOCK(bq); 2012 bd_flush(bd, bq); 2013 BQ_UNLOCK(bq); 2014 flushed++; 2015 } 2016 2017 return (flushed); 2018 } 2019 2020 static void 2021 bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock) 2022 { 2023 struct bufdomain *bd; 2024 2025 if (bp->b_qindex != QUEUE_NONE) 2026 panic("bq_insert: free buffer %p onto another queue?", bp); 2027 2028 bd = bufdomain(bp); 2029 if (bp->b_flags & B_AGE) { 2030 /* Place this buf directly on the real queue. */ 2031 if (bq->bq_index == QUEUE_CLEAN) 2032 bq = bd->bd_cleanq; 2033 BQ_LOCK(bq); 2034 TAILQ_INSERT_HEAD(&bq->bq_queue, bp, b_freelist); 2035 } else { 2036 BQ_LOCK(bq); 2037 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 2038 } 2039 bp->b_flags &= ~(B_AGE | B_REUSE); 2040 bq->bq_len++; 2041 bp->b_qindex = bq->bq_index; 2042 bp->b_subqueue = bq->bq_subqueue; 2043 2044 /* 2045 * Unlock before we notify so that we don't wakeup a waiter that 2046 * fails a trylock on the buf and sleeps again. 2047 */ 2048 if (unlock) 2049 BUF_UNLOCK(bp); 2050 2051 if (bp->b_qindex == QUEUE_CLEAN) { 2052 /* 2053 * Flush the per-cpu queue and notify any waiters. 2054 */ 2055 if (bd->bd_wanted || (bq != bd->bd_cleanq && 2056 bq->bq_len >= bd->bd_lim)) 2057 bd_flush(bd, bq); 2058 } 2059 BQ_UNLOCK(bq); 2060 } 2061 2062 /* 2063 * bufkva_free: 2064 * 2065 * Free the kva allocation for a buffer. 2066 * 2067 */ 2068 static void 2069 bufkva_free(struct buf *bp) 2070 { 2071 2072 #ifdef INVARIANTS 2073 if (bp->b_kvasize == 0) { 2074 KASSERT(bp->b_kvabase == unmapped_buf && 2075 bp->b_data == unmapped_buf, 2076 ("Leaked KVA space on %p", bp)); 2077 } else if (buf_mapped(bp)) 2078 BUF_CHECK_MAPPED(bp); 2079 else 2080 BUF_CHECK_UNMAPPED(bp); 2081 #endif 2082 if (bp->b_kvasize == 0) 2083 return; 2084 2085 vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, bp->b_kvasize); 2086 counter_u64_add(bufkvaspace, -bp->b_kvasize); 2087 counter_u64_add(buffreekvacnt, 1); 2088 bp->b_data = bp->b_kvabase = unmapped_buf; 2089 bp->b_kvasize = 0; 2090 } 2091 2092 /* 2093 * bufkva_alloc: 2094 * 2095 * Allocate the buffer KVA and set b_kvasize and b_kvabase. 2096 */ 2097 static int 2098 bufkva_alloc(struct buf *bp, int maxsize, int gbflags) 2099 { 2100 vm_offset_t addr; 2101 int error; 2102 2103 KASSERT((gbflags & GB_UNMAPPED) == 0 || (gbflags & GB_KVAALLOC) != 0, 2104 ("Invalid gbflags 0x%x in %s", gbflags, __func__)); 2105 MPASS((bp->b_flags & B_MAXPHYS) == 0); 2106 KASSERT(maxsize <= maxbcachebuf, 2107 ("bufkva_alloc kva too large %d %u", maxsize, maxbcachebuf)); 2108 2109 bufkva_free(bp); 2110 2111 addr = 0; 2112 error = vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr); 2113 if (error != 0) { 2114 /* 2115 * Buffer map is too fragmented. Request the caller 2116 * to defragment the map. 2117 */ 2118 return (error); 2119 } 2120 bp->b_kvabase = (caddr_t)addr; 2121 bp->b_kvasize = maxsize; 2122 counter_u64_add(bufkvaspace, bp->b_kvasize); 2123 if ((gbflags & GB_UNMAPPED) != 0) { 2124 bp->b_data = unmapped_buf; 2125 BUF_CHECK_UNMAPPED(bp); 2126 } else { 2127 bp->b_data = bp->b_kvabase; 2128 BUF_CHECK_MAPPED(bp); 2129 } 2130 return (0); 2131 } 2132 2133 /* 2134 * bufkva_reclaim: 2135 * 2136 * Reclaim buffer kva by freeing buffers holding kva. This is a vmem 2137 * callback that fires to avoid returning failure. 2138 */ 2139 static void 2140 bufkva_reclaim(vmem_t *vmem, int flags) 2141 { 2142 bool done; 2143 int q; 2144 int i; 2145 2146 done = false; 2147 for (i = 0; i < 5; i++) { 2148 for (q = 0; q < buf_domains; q++) 2149 if (buf_recycle(&bdomain[q], true) != 0) 2150 done = true; 2151 if (done) 2152 break; 2153 } 2154 return; 2155 } 2156 2157 /* 2158 * Attempt to initiate asynchronous I/O on read-ahead blocks. We must 2159 * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set, 2160 * the buffer is valid and we do not have to do anything. 2161 */ 2162 static void 2163 breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt, 2164 struct ucred * cred, int flags, void (*ckhashfunc)(struct buf *)) 2165 { 2166 struct buf *rabp; 2167 struct thread *td; 2168 int i; 2169 2170 td = curthread; 2171 2172 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 2173 if (inmem(vp, *rablkno)) 2174 continue; 2175 rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0); 2176 if ((rabp->b_flags & B_CACHE) != 0) { 2177 brelse(rabp); 2178 continue; 2179 } 2180 #ifdef RACCT 2181 if (racct_enable) { 2182 PROC_LOCK(curproc); 2183 racct_add_buf(curproc, rabp, 0); 2184 PROC_UNLOCK(curproc); 2185 } 2186 #endif /* RACCT */ 2187 td->td_ru.ru_inblock++; 2188 rabp->b_flags |= B_ASYNC; 2189 rabp->b_flags &= ~B_INVAL; 2190 if ((flags & GB_CKHASH) != 0) { 2191 rabp->b_flags |= B_CKHASH; 2192 rabp->b_ckhashcalc = ckhashfunc; 2193 } 2194 rabp->b_ioflags &= ~BIO_ERROR; 2195 rabp->b_iocmd = BIO_READ; 2196 if (rabp->b_rcred == NOCRED && cred != NOCRED) 2197 rabp->b_rcred = crhold(cred); 2198 vfs_busy_pages(rabp, 0); 2199 BUF_KERNPROC(rabp); 2200 rabp->b_iooffset = dbtob(rabp->b_blkno); 2201 bstrategy(rabp); 2202 } 2203 } 2204 2205 /* 2206 * Entry point for bread() and breadn() via #defines in sys/buf.h. 2207 * 2208 * Get a buffer with the specified data. Look in the cache first. We 2209 * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE 2210 * is set, the buffer is valid and we do not have to do anything, see 2211 * getblk(). Also starts asynchronous I/O on read-ahead blocks. 2212 * 2213 * Always return a NULL buffer pointer (in bpp) when returning an error. 2214 * 2215 * The blkno parameter is the logical block being requested. Normally 2216 * the mapping of logical block number to disk block address is done 2217 * by calling VOP_BMAP(). However, if the mapping is already known, the 2218 * disk block address can be passed using the dblkno parameter. If the 2219 * disk block address is not known, then the same value should be passed 2220 * for blkno and dblkno. 2221 */ 2222 int 2223 breadn_flags(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, 2224 daddr_t *rablkno, int *rabsize, int cnt, struct ucred *cred, int flags, 2225 void (*ckhashfunc)(struct buf *), struct buf **bpp) 2226 { 2227 struct buf *bp; 2228 struct thread *td; 2229 int error, readwait, rv; 2230 2231 CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size); 2232 td = curthread; 2233 /* 2234 * Can only return NULL if GB_LOCK_NOWAIT or GB_SPARSE flags 2235 * are specified. 2236 */ 2237 error = getblkx(vp, blkno, dblkno, size, 0, 0, flags, &bp); 2238 if (error != 0) { 2239 *bpp = NULL; 2240 return (error); 2241 } 2242 KASSERT(blkno == bp->b_lblkno, 2243 ("getblkx returned buffer for blkno %jd instead of blkno %jd", 2244 (intmax_t)bp->b_lblkno, (intmax_t)blkno)); 2245 flags &= ~GB_NOSPARSE; 2246 *bpp = bp; 2247 2248 /* 2249 * If not found in cache, do some I/O 2250 */ 2251 readwait = 0; 2252 if ((bp->b_flags & B_CACHE) == 0) { 2253 #ifdef RACCT 2254 if (racct_enable) { 2255 PROC_LOCK(td->td_proc); 2256 racct_add_buf(td->td_proc, bp, 0); 2257 PROC_UNLOCK(td->td_proc); 2258 } 2259 #endif /* RACCT */ 2260 td->td_ru.ru_inblock++; 2261 bp->b_iocmd = BIO_READ; 2262 bp->b_flags &= ~B_INVAL; 2263 if ((flags & GB_CKHASH) != 0) { 2264 bp->b_flags |= B_CKHASH; 2265 bp->b_ckhashcalc = ckhashfunc; 2266 } 2267 if ((flags & GB_CVTENXIO) != 0) 2268 bp->b_xflags |= BX_CVTENXIO; 2269 bp->b_ioflags &= ~BIO_ERROR; 2270 if (bp->b_rcred == NOCRED && cred != NOCRED) 2271 bp->b_rcred = crhold(cred); 2272 vfs_busy_pages(bp, 0); 2273 bp->b_iooffset = dbtob(bp->b_blkno); 2274 bstrategy(bp); 2275 ++readwait; 2276 } 2277 2278 /* 2279 * Attempt to initiate asynchronous I/O on read-ahead blocks. 2280 */ 2281 breada(vp, rablkno, rabsize, cnt, cred, flags, ckhashfunc); 2282 2283 rv = 0; 2284 if (readwait) { 2285 rv = bufwait(bp); 2286 if (rv != 0) { 2287 brelse(bp); 2288 *bpp = NULL; 2289 } 2290 } 2291 return (rv); 2292 } 2293 2294 /* 2295 * Write, release buffer on completion. (Done by iodone 2296 * if async). Do not bother writing anything if the buffer 2297 * is invalid. 2298 * 2299 * Note that we set B_CACHE here, indicating that buffer is 2300 * fully valid and thus cacheable. This is true even of NFS 2301 * now so we set it generally. This could be set either here 2302 * or in biodone() since the I/O is synchronous. We put it 2303 * here. 2304 */ 2305 int 2306 bufwrite(struct buf *bp) 2307 { 2308 struct vnode *vp; 2309 long space; 2310 int oldflags, retval; 2311 bool vp_md; 2312 2313 CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2314 if ((bp->b_bufobj->bo_flag & BO_DEAD) != 0) { 2315 bp->b_flags |= B_INVAL | B_RELBUF; 2316 bp->b_flags &= ~B_CACHE; 2317 brelse(bp); 2318 return (ENXIO); 2319 } 2320 if ((bp->b_flags & B_INVAL) != 0) { 2321 brelse(bp); 2322 return (0); 2323 } 2324 2325 if ((bp->b_flags & B_BARRIER) != 0) 2326 atomic_add_long(&barrierwrites, 1); 2327 2328 oldflags = bp->b_flags; 2329 2330 KASSERT((bp->b_vflags & BV_BKGRDINPROG) == 0, 2331 ("FFS background buffer should not get here %p", bp)); 2332 2333 vp = bp->b_vp; 2334 vp_md = vp != NULL && (vp->v_vflag & VV_MD) != 0; 2335 2336 /* 2337 * Mark the buffer clean. Increment the bufobj write count 2338 * before bundirty() call, to prevent other thread from seeing 2339 * empty dirty list and zero counter for writes in progress, 2340 * falsely indicating that the bufobj is clean. 2341 */ 2342 bufobj_wref(bp->b_bufobj); 2343 bundirty(bp); 2344 2345 bp->b_flags &= ~B_DONE; 2346 bp->b_ioflags &= ~BIO_ERROR; 2347 bp->b_flags |= B_CACHE; 2348 bp->b_iocmd = BIO_WRITE; 2349 2350 vfs_busy_pages(bp, 1); 2351 2352 /* 2353 * Normal bwrites pipeline writes 2354 */ 2355 bp->b_runningbufspace = bp->b_bufsize; 2356 space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace); 2357 2358 #ifdef RACCT 2359 if (racct_enable) { 2360 PROC_LOCK(curproc); 2361 racct_add_buf(curproc, bp, 1); 2362 PROC_UNLOCK(curproc); 2363 } 2364 #endif /* RACCT */ 2365 curthread->td_ru.ru_oublock++; 2366 if ((oldflags & B_ASYNC) != 0) 2367 BUF_KERNPROC(bp); 2368 bp->b_iooffset = dbtob(bp->b_blkno); 2369 buf_track(bp, __func__); 2370 bstrategy(bp); 2371 2372 if ((oldflags & B_ASYNC) == 0) { 2373 retval = bufwait(bp); 2374 brelse(bp); 2375 return (retval); 2376 } else if (space > hirunningspace) { 2377 /* 2378 * Don't allow the async write to saturate the I/O 2379 * system. We do not block here if it is the update 2380 * or syncer daemon trying to clean up as that can 2381 * lead to deadlock. 2382 */ 2383 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md) 2384 waitrunningbufspace(); 2385 } 2386 2387 return (0); 2388 } 2389 2390 void 2391 bufbdflush(struct bufobj *bo, struct buf *bp) 2392 { 2393 struct buf *nbp; 2394 struct bufdomain *bd; 2395 2396 bd = &bdomain[bo->bo_domain]; 2397 if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh + 10) { 2398 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); 2399 altbufferflushes++; 2400 } else if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh) { 2401 BO_LOCK(bo); 2402 /* 2403 * Try to find a buffer to flush. 2404 */ 2405 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2406 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2407 BUF_LOCK(nbp, 2408 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2409 continue; 2410 if (bp == nbp) 2411 panic("bdwrite: found ourselves"); 2412 BO_UNLOCK(bo); 2413 /* Don't countdeps with the bo lock held. */ 2414 if (buf_countdeps(nbp, 0)) { 2415 BO_LOCK(bo); 2416 BUF_UNLOCK(nbp); 2417 continue; 2418 } 2419 if (nbp->b_flags & B_CLUSTEROK) { 2420 vfs_bio_awrite(nbp); 2421 } else { 2422 bremfree(nbp); 2423 bawrite(nbp); 2424 } 2425 dirtybufferflushes++; 2426 break; 2427 } 2428 if (nbp == NULL) 2429 BO_UNLOCK(bo); 2430 } 2431 } 2432 2433 /* 2434 * Delayed write. (Buffer is marked dirty). Do not bother writing 2435 * anything if the buffer is marked invalid. 2436 * 2437 * Note that since the buffer must be completely valid, we can safely 2438 * set B_CACHE. In fact, we have to set B_CACHE here rather then in 2439 * biodone() in order to prevent getblk from writing the buffer 2440 * out synchronously. 2441 */ 2442 void 2443 bdwrite(struct buf *bp) 2444 { 2445 struct thread *td = curthread; 2446 struct vnode *vp; 2447 struct bufobj *bo; 2448 2449 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2450 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2451 KASSERT((bp->b_flags & B_BARRIER) == 0, 2452 ("Barrier request in delayed write %p", bp)); 2453 2454 if (bp->b_flags & B_INVAL) { 2455 brelse(bp); 2456 return; 2457 } 2458 2459 /* 2460 * If we have too many dirty buffers, don't create any more. 2461 * If we are wildly over our limit, then force a complete 2462 * cleanup. Otherwise, just keep the situation from getting 2463 * out of control. Note that we have to avoid a recursive 2464 * disaster and not try to clean up after our own cleanup! 2465 */ 2466 vp = bp->b_vp; 2467 bo = bp->b_bufobj; 2468 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) { 2469 td->td_pflags |= TDP_INBDFLUSH; 2470 BO_BDFLUSH(bo, bp); 2471 td->td_pflags &= ~TDP_INBDFLUSH; 2472 } else 2473 recursiveflushes++; 2474 2475 bdirty(bp); 2476 /* 2477 * Set B_CACHE, indicating that the buffer is fully valid. This is 2478 * true even of NFS now. 2479 */ 2480 bp->b_flags |= B_CACHE; 2481 2482 /* 2483 * This bmap keeps the system from needing to do the bmap later, 2484 * perhaps when the system is attempting to do a sync. Since it 2485 * is likely that the indirect block -- or whatever other datastructure 2486 * that the filesystem needs is still in memory now, it is a good 2487 * thing to do this. Note also, that if the pageout daemon is 2488 * requesting a sync -- there might not be enough memory to do 2489 * the bmap then... So, this is important to do. 2490 */ 2491 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) { 2492 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 2493 } 2494 2495 buf_track(bp, __func__); 2496 2497 /* 2498 * Set the *dirty* buffer range based upon the VM system dirty 2499 * pages. 2500 * 2501 * Mark the buffer pages as clean. We need to do this here to 2502 * satisfy the vnode_pager and the pageout daemon, so that it 2503 * thinks that the pages have been "cleaned". Note that since 2504 * the pages are in a delayed write buffer -- the VFS layer 2505 * "will" see that the pages get written out on the next sync, 2506 * or perhaps the cluster will be completed. 2507 */ 2508 vfs_clean_pages_dirty_buf(bp); 2509 bqrelse(bp); 2510 2511 /* 2512 * note: we cannot initiate I/O from a bdwrite even if we wanted to, 2513 * due to the softdep code. 2514 */ 2515 } 2516 2517 /* 2518 * bdirty: 2519 * 2520 * Turn buffer into delayed write request. We must clear BIO_READ and 2521 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to 2522 * itself to properly update it in the dirty/clean lists. We mark it 2523 * B_DONE to ensure that any asynchronization of the buffer properly 2524 * clears B_DONE ( else a panic will occur later ). 2525 * 2526 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which 2527 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty() 2528 * should only be called if the buffer is known-good. 2529 * 2530 * Since the buffer is not on a queue, we do not update the numfreebuffers 2531 * count. 2532 * 2533 * The buffer must be on QUEUE_NONE. 2534 */ 2535 void 2536 bdirty(struct buf *bp) 2537 { 2538 2539 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X", 2540 bp, bp->b_vp, bp->b_flags); 2541 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2542 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2543 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2544 bp->b_flags &= ~(B_RELBUF); 2545 bp->b_iocmd = BIO_WRITE; 2546 2547 if ((bp->b_flags & B_DELWRI) == 0) { 2548 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI; 2549 reassignbuf(bp); 2550 bdirtyadd(bp); 2551 } 2552 } 2553 2554 /* 2555 * bundirty: 2556 * 2557 * Clear B_DELWRI for buffer. 2558 * 2559 * Since the buffer is not on a queue, we do not update the numfreebuffers 2560 * count. 2561 * 2562 * The buffer must be on QUEUE_NONE. 2563 */ 2564 2565 void 2566 bundirty(struct buf *bp) 2567 { 2568 2569 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2570 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2571 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2572 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2573 2574 if (bp->b_flags & B_DELWRI) { 2575 bp->b_flags &= ~B_DELWRI; 2576 reassignbuf(bp); 2577 bdirtysub(bp); 2578 } 2579 /* 2580 * Since it is now being written, we can clear its deferred write flag. 2581 */ 2582 bp->b_flags &= ~B_DEFERRED; 2583 } 2584 2585 /* 2586 * bawrite: 2587 * 2588 * Asynchronous write. Start output on a buffer, but do not wait for 2589 * it to complete. The buffer is released when the output completes. 2590 * 2591 * bwrite() ( or the VOP routine anyway ) is responsible for handling 2592 * B_INVAL buffers. Not us. 2593 */ 2594 void 2595 bawrite(struct buf *bp) 2596 { 2597 2598 bp->b_flags |= B_ASYNC; 2599 (void) bwrite(bp); 2600 } 2601 2602 /* 2603 * babarrierwrite: 2604 * 2605 * Asynchronous barrier write. Start output on a buffer, but do not 2606 * wait for it to complete. Place a write barrier after this write so 2607 * that this buffer and all buffers written before it are committed to 2608 * the disk before any buffers written after this write are committed 2609 * to the disk. The buffer is released when the output completes. 2610 */ 2611 void 2612 babarrierwrite(struct buf *bp) 2613 { 2614 2615 bp->b_flags |= B_ASYNC | B_BARRIER; 2616 (void) bwrite(bp); 2617 } 2618 2619 /* 2620 * bbarrierwrite: 2621 * 2622 * Synchronous barrier write. Start output on a buffer and wait for 2623 * it to complete. Place a write barrier after this write so that 2624 * this buffer and all buffers written before it are committed to 2625 * the disk before any buffers written after this write are committed 2626 * to the disk. The buffer is released when the output completes. 2627 */ 2628 int 2629 bbarrierwrite(struct buf *bp) 2630 { 2631 2632 bp->b_flags |= B_BARRIER; 2633 return (bwrite(bp)); 2634 } 2635 2636 /* 2637 * bwillwrite: 2638 * 2639 * Called prior to the locking of any vnodes when we are expecting to 2640 * write. We do not want to starve the buffer cache with too many 2641 * dirty buffers so we block here. By blocking prior to the locking 2642 * of any vnodes we attempt to avoid the situation where a locked vnode 2643 * prevents the various system daemons from flushing related buffers. 2644 */ 2645 void 2646 bwillwrite(void) 2647 { 2648 2649 if (buf_dirty_count_severe()) { 2650 mtx_lock(&bdirtylock); 2651 while (buf_dirty_count_severe()) { 2652 bdirtywait = 1; 2653 msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4), 2654 "flswai", 0); 2655 } 2656 mtx_unlock(&bdirtylock); 2657 } 2658 } 2659 2660 /* 2661 * Return true if we have too many dirty buffers. 2662 */ 2663 int 2664 buf_dirty_count_severe(void) 2665 { 2666 2667 return (!BIT_EMPTY(BUF_DOMAINS, &bdhidirty)); 2668 } 2669 2670 /* 2671 * brelse: 2672 * 2673 * Release a busy buffer and, if requested, free its resources. The 2674 * buffer will be stashed in the appropriate bufqueue[] allowing it 2675 * to be accessed later as a cache entity or reused for other purposes. 2676 */ 2677 void 2678 brelse(struct buf *bp) 2679 { 2680 struct mount *v_mnt; 2681 int qindex; 2682 2683 /* 2684 * Many functions erroneously call brelse with a NULL bp under rare 2685 * error conditions. Simply return when called with a NULL bp. 2686 */ 2687 if (bp == NULL) 2688 return; 2689 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X", 2690 bp, bp->b_vp, bp->b_flags); 2691 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2692 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2693 KASSERT((bp->b_flags & B_VMIO) != 0 || (bp->b_flags & B_NOREUSE) == 0, 2694 ("brelse: non-VMIO buffer marked NOREUSE")); 2695 2696 if (BUF_LOCKRECURSED(bp)) { 2697 /* 2698 * Do not process, in particular, do not handle the 2699 * B_INVAL/B_RELBUF and do not release to free list. 2700 */ 2701 BUF_UNLOCK(bp); 2702 return; 2703 } 2704 2705 if (bp->b_flags & B_MANAGED) { 2706 bqrelse(bp); 2707 return; 2708 } 2709 2710 if (LIST_EMPTY(&bp->b_dep)) { 2711 bp->b_flags &= ~B_IOSTARTED; 2712 } else { 2713 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2714 ("brelse: SU io not finished bp %p", bp)); 2715 } 2716 2717 if ((bp->b_vflags & (BV_BKGRDINPROG | BV_BKGRDERR)) == BV_BKGRDERR) { 2718 BO_LOCK(bp->b_bufobj); 2719 bp->b_vflags &= ~BV_BKGRDERR; 2720 BO_UNLOCK(bp->b_bufobj); 2721 bdirty(bp); 2722 } 2723 2724 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2725 (bp->b_flags & B_INVALONERR)) { 2726 /* 2727 * Forced invalidation of dirty buffer contents, to be used 2728 * after a failed write in the rare case that the loss of the 2729 * contents is acceptable. The buffer is invalidated and 2730 * freed. 2731 */ 2732 bp->b_flags |= B_INVAL | B_RELBUF | B_NOCACHE; 2733 bp->b_flags &= ~(B_ASYNC | B_CACHE); 2734 } 2735 2736 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2737 (bp->b_error != ENXIO || !LIST_EMPTY(&bp->b_dep)) && 2738 !(bp->b_flags & B_INVAL)) { 2739 /* 2740 * Failed write, redirty. All errors except ENXIO (which 2741 * means the device is gone) are treated as being 2742 * transient. 2743 * 2744 * XXX Treating EIO as transient is not correct; the 2745 * contract with the local storage device drivers is that 2746 * they will only return EIO once the I/O is no longer 2747 * retriable. Network I/O also respects this through the 2748 * guarantees of TCP and/or the internal retries of NFS. 2749 * ENOMEM might be transient, but we also have no way of 2750 * knowing when its ok to retry/reschedule. In general, 2751 * this entire case should be made obsolete through better 2752 * error handling/recovery and resource scheduling. 2753 * 2754 * Do this also for buffers that failed with ENXIO, but have 2755 * non-empty dependencies - the soft updates code might need 2756 * to access the buffer to untangle them. 2757 * 2758 * Must clear BIO_ERROR to prevent pages from being scrapped. 2759 */ 2760 bp->b_ioflags &= ~BIO_ERROR; 2761 bdirty(bp); 2762 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) || 2763 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) { 2764 /* 2765 * Either a failed read I/O, or we were asked to free or not 2766 * cache the buffer, or we failed to write to a device that's 2767 * no longer present. 2768 */ 2769 bp->b_flags |= B_INVAL; 2770 if (!LIST_EMPTY(&bp->b_dep)) 2771 buf_deallocate(bp); 2772 if (bp->b_flags & B_DELWRI) 2773 bdirtysub(bp); 2774 bp->b_flags &= ~(B_DELWRI | B_CACHE); 2775 if ((bp->b_flags & B_VMIO) == 0) { 2776 allocbuf(bp, 0); 2777 if (bp->b_vp) 2778 brelvp(bp); 2779 } 2780 } 2781 2782 /* 2783 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_truncate() 2784 * is called with B_DELWRI set, the underlying pages may wind up 2785 * getting freed causing a previous write (bdwrite()) to get 'lost' 2786 * because pages associated with a B_DELWRI bp are marked clean. 2787 * 2788 * We still allow the B_INVAL case to call vfs_vmio_truncate(), even 2789 * if B_DELWRI is set. 2790 */ 2791 if (bp->b_flags & B_DELWRI) 2792 bp->b_flags &= ~B_RELBUF; 2793 2794 /* 2795 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 2796 * constituted, not even NFS buffers now. Two flags effect this. If 2797 * B_INVAL, the struct buf is invalidated but the VM object is kept 2798 * around ( i.e. so it is trivial to reconstitute the buffer later ). 2799 * 2800 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be 2801 * invalidated. BIO_ERROR cannot be set for a failed write unless the 2802 * buffer is also B_INVAL because it hits the re-dirtying code above. 2803 * 2804 * Normally we can do this whether a buffer is B_DELWRI or not. If 2805 * the buffer is an NFS buffer, it is tracking piecemeal writes or 2806 * the commit state and we cannot afford to lose the buffer. If the 2807 * buffer has a background write in progress, we need to keep it 2808 * around to prevent it from being reconstituted and starting a second 2809 * background write. 2810 */ 2811 2812 v_mnt = bp->b_vp != NULL ? bp->b_vp->v_mount : NULL; 2813 2814 if ((bp->b_flags & B_VMIO) && (bp->b_flags & B_NOCACHE || 2815 (bp->b_ioflags & BIO_ERROR && bp->b_iocmd == BIO_READ)) && 2816 (v_mnt == NULL || (v_mnt->mnt_vfc->vfc_flags & VFCF_NETWORK) == 0 || 2817 vn_isdisk(bp->b_vp) || (bp->b_flags & B_DELWRI) == 0)) { 2818 vfs_vmio_invalidate(bp); 2819 allocbuf(bp, 0); 2820 } 2821 2822 if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0 || 2823 (bp->b_flags & (B_DELWRI | B_NOREUSE)) == B_NOREUSE) { 2824 allocbuf(bp, 0); 2825 bp->b_flags &= ~B_NOREUSE; 2826 if (bp->b_vp != NULL) 2827 brelvp(bp); 2828 } 2829 2830 /* 2831 * If the buffer has junk contents signal it and eventually 2832 * clean up B_DELWRI and diassociate the vnode so that gbincore() 2833 * doesn't find it. 2834 */ 2835 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 || 2836 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0) 2837 bp->b_flags |= B_INVAL; 2838 if (bp->b_flags & B_INVAL) { 2839 if (bp->b_flags & B_DELWRI) 2840 bundirty(bp); 2841 if (bp->b_vp) 2842 brelvp(bp); 2843 } 2844 2845 buf_track(bp, __func__); 2846 2847 /* buffers with no memory */ 2848 if (bp->b_bufsize == 0) { 2849 buf_free(bp); 2850 return; 2851 } 2852 /* buffers with junk contents */ 2853 if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) || 2854 (bp->b_ioflags & BIO_ERROR)) { 2855 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 2856 if (bp->b_vflags & BV_BKGRDINPROG) 2857 panic("losing buffer 2"); 2858 qindex = QUEUE_CLEAN; 2859 bp->b_flags |= B_AGE; 2860 /* remaining buffers */ 2861 } else if (bp->b_flags & B_DELWRI) 2862 qindex = QUEUE_DIRTY; 2863 else 2864 qindex = QUEUE_CLEAN; 2865 2866 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) 2867 panic("brelse: not dirty"); 2868 2869 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_RELBUF | B_DIRECT); 2870 bp->b_xflags &= ~(BX_CVTENXIO); 2871 /* binsfree unlocks bp. */ 2872 binsfree(bp, qindex); 2873 } 2874 2875 /* 2876 * Release a buffer back to the appropriate queue but do not try to free 2877 * it. The buffer is expected to be used again soon. 2878 * 2879 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by 2880 * biodone() to requeue an async I/O on completion. It is also used when 2881 * known good buffers need to be requeued but we think we may need the data 2882 * again soon. 2883 * 2884 * XXX we should be able to leave the B_RELBUF hint set on completion. 2885 */ 2886 void 2887 bqrelse(struct buf *bp) 2888 { 2889 int qindex; 2890 2891 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2892 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2893 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2894 2895 qindex = QUEUE_NONE; 2896 if (BUF_LOCKRECURSED(bp)) { 2897 /* do not release to free list */ 2898 BUF_UNLOCK(bp); 2899 return; 2900 } 2901 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 2902 bp->b_xflags &= ~(BX_CVTENXIO); 2903 2904 if (LIST_EMPTY(&bp->b_dep)) { 2905 bp->b_flags &= ~B_IOSTARTED; 2906 } else { 2907 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2908 ("bqrelse: SU io not finished bp %p", bp)); 2909 } 2910 2911 if (bp->b_flags & B_MANAGED) { 2912 if (bp->b_flags & B_REMFREE) 2913 bremfreef(bp); 2914 goto out; 2915 } 2916 2917 /* buffers with stale but valid contents */ 2918 if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG | 2919 BV_BKGRDERR)) == BV_BKGRDERR) { 2920 BO_LOCK(bp->b_bufobj); 2921 bp->b_vflags &= ~BV_BKGRDERR; 2922 BO_UNLOCK(bp->b_bufobj); 2923 qindex = QUEUE_DIRTY; 2924 } else { 2925 if ((bp->b_flags & B_DELWRI) == 0 && 2926 (bp->b_xflags & BX_VNDIRTY)) 2927 panic("bqrelse: not dirty"); 2928 if ((bp->b_flags & B_NOREUSE) != 0) { 2929 brelse(bp); 2930 return; 2931 } 2932 qindex = QUEUE_CLEAN; 2933 } 2934 buf_track(bp, __func__); 2935 /* binsfree unlocks bp. */ 2936 binsfree(bp, qindex); 2937 return; 2938 2939 out: 2940 buf_track(bp, __func__); 2941 /* unlock */ 2942 BUF_UNLOCK(bp); 2943 } 2944 2945 /* 2946 * Complete I/O to a VMIO backed page. Validate the pages as appropriate, 2947 * restore bogus pages. 2948 */ 2949 static void 2950 vfs_vmio_iodone(struct buf *bp) 2951 { 2952 vm_ooffset_t foff; 2953 vm_page_t m; 2954 vm_object_t obj; 2955 struct vnode *vp __unused; 2956 int i, iosize, resid; 2957 bool bogus; 2958 2959 obj = bp->b_bufobj->bo_object; 2960 KASSERT(blockcount_read(&obj->paging_in_progress) >= bp->b_npages, 2961 ("vfs_vmio_iodone: paging in progress(%d) < b_npages(%d)", 2962 blockcount_read(&obj->paging_in_progress), bp->b_npages)); 2963 2964 vp = bp->b_vp; 2965 VNPASS(vp->v_holdcnt > 0, vp); 2966 VNPASS(vp->v_object != NULL, vp); 2967 2968 foff = bp->b_offset; 2969 KASSERT(bp->b_offset != NOOFFSET, 2970 ("vfs_vmio_iodone: bp %p has no buffer offset", bp)); 2971 2972 bogus = false; 2973 iosize = bp->b_bcount - bp->b_resid; 2974 for (i = 0; i < bp->b_npages; i++) { 2975 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff; 2976 if (resid > iosize) 2977 resid = iosize; 2978 2979 /* 2980 * cleanup bogus pages, restoring the originals 2981 */ 2982 m = bp->b_pages[i]; 2983 if (m == bogus_page) { 2984 bogus = true; 2985 m = vm_page_relookup(obj, OFF_TO_IDX(foff)); 2986 if (m == NULL) 2987 panic("biodone: page disappeared!"); 2988 bp->b_pages[i] = m; 2989 } else if ((bp->b_iocmd == BIO_READ) && resid > 0) { 2990 /* 2991 * In the write case, the valid and clean bits are 2992 * already changed correctly ( see bdwrite() ), so we 2993 * only need to do this here in the read case. 2994 */ 2995 KASSERT((m->dirty & vm_page_bits(foff & PAGE_MASK, 2996 resid)) == 0, ("vfs_vmio_iodone: page %p " 2997 "has unexpected dirty bits", m)); 2998 vfs_page_set_valid(bp, foff, m); 2999 } 3000 KASSERT(OFF_TO_IDX(foff) == m->pindex, 3001 ("vfs_vmio_iodone: foff(%jd)/pindex(%ju) mismatch", 3002 (intmax_t)foff, (uintmax_t)m->pindex)); 3003 3004 vm_page_sunbusy(m); 3005 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3006 iosize -= resid; 3007 } 3008 vm_object_pip_wakeupn(obj, bp->b_npages); 3009 if (bogus && buf_mapped(bp)) { 3010 BUF_CHECK_MAPPED(bp); 3011 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 3012 bp->b_pages, bp->b_npages); 3013 } 3014 } 3015 3016 /* 3017 * Perform page invalidation when a buffer is released. The fully invalid 3018 * pages will be reclaimed later in vfs_vmio_truncate(). 3019 */ 3020 static void 3021 vfs_vmio_invalidate(struct buf *bp) 3022 { 3023 vm_object_t obj; 3024 vm_page_t m; 3025 int flags, i, resid, poffset, presid; 3026 3027 if (buf_mapped(bp)) { 3028 BUF_CHECK_MAPPED(bp); 3029 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages); 3030 } else 3031 BUF_CHECK_UNMAPPED(bp); 3032 /* 3033 * Get the base offset and length of the buffer. Note that 3034 * in the VMIO case if the buffer block size is not 3035 * page-aligned then b_data pointer may not be page-aligned. 3036 * But our b_pages[] array *IS* page aligned. 3037 * 3038 * block sizes less then DEV_BSIZE (usually 512) are not 3039 * supported due to the page granularity bits (m->valid, 3040 * m->dirty, etc...). 3041 * 3042 * See man buf(9) for more information 3043 */ 3044 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3045 obj = bp->b_bufobj->bo_object; 3046 resid = bp->b_bufsize; 3047 poffset = bp->b_offset & PAGE_MASK; 3048 VM_OBJECT_WLOCK(obj); 3049 for (i = 0; i < bp->b_npages; i++) { 3050 m = bp->b_pages[i]; 3051 if (m == bogus_page) 3052 panic("vfs_vmio_invalidate: Unexpected bogus page."); 3053 bp->b_pages[i] = NULL; 3054 3055 presid = resid > (PAGE_SIZE - poffset) ? 3056 (PAGE_SIZE - poffset) : resid; 3057 KASSERT(presid >= 0, ("brelse: extra page")); 3058 vm_page_busy_acquire(m, VM_ALLOC_SBUSY); 3059 if (pmap_page_wired_mappings(m) == 0) 3060 vm_page_set_invalid(m, poffset, presid); 3061 vm_page_sunbusy(m); 3062 vm_page_release_locked(m, flags); 3063 resid -= presid; 3064 poffset = 0; 3065 } 3066 VM_OBJECT_WUNLOCK(obj); 3067 bp->b_npages = 0; 3068 } 3069 3070 /* 3071 * Page-granular truncation of an existing VMIO buffer. 3072 */ 3073 static void 3074 vfs_vmio_truncate(struct buf *bp, int desiredpages) 3075 { 3076 vm_object_t obj; 3077 vm_page_t m; 3078 int flags, i; 3079 3080 if (bp->b_npages == desiredpages) 3081 return; 3082 3083 if (buf_mapped(bp)) { 3084 BUF_CHECK_MAPPED(bp); 3085 pmap_qremove((vm_offset_t)trunc_page((vm_offset_t)bp->b_data) + 3086 (desiredpages << PAGE_SHIFT), bp->b_npages - desiredpages); 3087 } else 3088 BUF_CHECK_UNMAPPED(bp); 3089 3090 /* 3091 * The object lock is needed only if we will attempt to free pages. 3092 */ 3093 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3094 if ((bp->b_flags & B_DIRECT) != 0) { 3095 flags |= VPR_TRYFREE; 3096 obj = bp->b_bufobj->bo_object; 3097 VM_OBJECT_WLOCK(obj); 3098 } else { 3099 obj = NULL; 3100 } 3101 for (i = desiredpages; i < bp->b_npages; i++) { 3102 m = bp->b_pages[i]; 3103 KASSERT(m != bogus_page, ("allocbuf: bogus page found")); 3104 bp->b_pages[i] = NULL; 3105 if (obj != NULL) 3106 vm_page_release_locked(m, flags); 3107 else 3108 vm_page_release(m, flags); 3109 } 3110 if (obj != NULL) 3111 VM_OBJECT_WUNLOCK(obj); 3112 bp->b_npages = desiredpages; 3113 } 3114 3115 /* 3116 * Byte granular extension of VMIO buffers. 3117 */ 3118 static void 3119 vfs_vmio_extend(struct buf *bp, int desiredpages, int size) 3120 { 3121 /* 3122 * We are growing the buffer, possibly in a 3123 * byte-granular fashion. 3124 */ 3125 vm_object_t obj; 3126 vm_offset_t toff; 3127 vm_offset_t tinc; 3128 vm_page_t m; 3129 3130 /* 3131 * Step 1, bring in the VM pages from the object, allocating 3132 * them if necessary. We must clear B_CACHE if these pages 3133 * are not valid for the range covered by the buffer. 3134 */ 3135 obj = bp->b_bufobj->bo_object; 3136 if (bp->b_npages < desiredpages) { 3137 KASSERT(desiredpages <= atop(maxbcachebuf), 3138 ("vfs_vmio_extend past maxbcachebuf %p %d %u", 3139 bp, desiredpages, maxbcachebuf)); 3140 3141 /* 3142 * We must allocate system pages since blocking 3143 * here could interfere with paging I/O, no 3144 * matter which process we are. 3145 * 3146 * Only exclusive busy can be tested here. 3147 * Blocking on shared busy might lead to 3148 * deadlocks once allocbuf() is called after 3149 * pages are vfs_busy_pages(). 3150 */ 3151 (void)vm_page_grab_pages_unlocked(obj, 3152 OFF_TO_IDX(bp->b_offset) + bp->b_npages, 3153 VM_ALLOC_SYSTEM | VM_ALLOC_IGN_SBUSY | 3154 VM_ALLOC_NOBUSY | VM_ALLOC_WIRED, 3155 &bp->b_pages[bp->b_npages], desiredpages - bp->b_npages); 3156 bp->b_npages = desiredpages; 3157 } 3158 3159 /* 3160 * Step 2. We've loaded the pages into the buffer, 3161 * we have to figure out if we can still have B_CACHE 3162 * set. Note that B_CACHE is set according to the 3163 * byte-granular range ( bcount and size ), not the 3164 * aligned range ( newbsize ). 3165 * 3166 * The VM test is against m->valid, which is DEV_BSIZE 3167 * aligned. Needless to say, the validity of the data 3168 * needs to also be DEV_BSIZE aligned. Note that this 3169 * fails with NFS if the server or some other client 3170 * extends the file's EOF. If our buffer is resized, 3171 * B_CACHE may remain set! XXX 3172 */ 3173 toff = bp->b_bcount; 3174 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK); 3175 while ((bp->b_flags & B_CACHE) && toff < size) { 3176 vm_pindex_t pi; 3177 3178 if (tinc > (size - toff)) 3179 tinc = size - toff; 3180 pi = ((bp->b_offset & PAGE_MASK) + toff) >> PAGE_SHIFT; 3181 m = bp->b_pages[pi]; 3182 vfs_buf_test_cache(bp, bp->b_offset, toff, tinc, m); 3183 toff += tinc; 3184 tinc = PAGE_SIZE; 3185 } 3186 3187 /* 3188 * Step 3, fixup the KVA pmap. 3189 */ 3190 if (buf_mapped(bp)) 3191 bpmap_qenter(bp); 3192 else 3193 BUF_CHECK_UNMAPPED(bp); 3194 } 3195 3196 /* 3197 * Check to see if a block at a particular lbn is available for a clustered 3198 * write. 3199 */ 3200 static int 3201 vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno) 3202 { 3203 struct buf *bpa; 3204 int match; 3205 3206 match = 0; 3207 3208 /* If the buf isn't in core skip it */ 3209 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL) 3210 return (0); 3211 3212 /* If the buf is busy we don't want to wait for it */ 3213 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 3214 return (0); 3215 3216 /* Only cluster with valid clusterable delayed write buffers */ 3217 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) != 3218 (B_DELWRI | B_CLUSTEROK)) 3219 goto done; 3220 3221 if (bpa->b_bufsize != size) 3222 goto done; 3223 3224 /* 3225 * Check to see if it is in the expected place on disk and that the 3226 * block has been mapped. 3227 */ 3228 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno)) 3229 match = 1; 3230 done: 3231 BUF_UNLOCK(bpa); 3232 return (match); 3233 } 3234 3235 /* 3236 * vfs_bio_awrite: 3237 * 3238 * Implement clustered async writes for clearing out B_DELWRI buffers. 3239 * This is much better then the old way of writing only one buffer at 3240 * a time. Note that we may not be presented with the buffers in the 3241 * correct order, so we search for the cluster in both directions. 3242 */ 3243 int 3244 vfs_bio_awrite(struct buf *bp) 3245 { 3246 struct bufobj *bo; 3247 int i; 3248 int j; 3249 daddr_t lblkno = bp->b_lblkno; 3250 struct vnode *vp = bp->b_vp; 3251 int ncl; 3252 int nwritten; 3253 int size; 3254 int maxcl; 3255 int gbflags; 3256 3257 bo = &vp->v_bufobj; 3258 gbflags = (bp->b_data == unmapped_buf) ? GB_UNMAPPED : 0; 3259 /* 3260 * right now we support clustered writing only to regular files. If 3261 * we find a clusterable block we could be in the middle of a cluster 3262 * rather then at the beginning. 3263 */ 3264 if ((vp->v_type == VREG) && 3265 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 3266 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 3267 size = vp->v_mount->mnt_stat.f_iosize; 3268 maxcl = maxphys / size; 3269 3270 BO_RLOCK(bo); 3271 for (i = 1; i < maxcl; i++) 3272 if (vfs_bio_clcheck(vp, size, lblkno + i, 3273 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0) 3274 break; 3275 3276 for (j = 1; i + j <= maxcl && j <= lblkno; j++) 3277 if (vfs_bio_clcheck(vp, size, lblkno - j, 3278 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0) 3279 break; 3280 BO_RUNLOCK(bo); 3281 --j; 3282 ncl = i + j; 3283 /* 3284 * this is a possible cluster write 3285 */ 3286 if (ncl != 1) { 3287 BUF_UNLOCK(bp); 3288 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, 3289 gbflags); 3290 return (nwritten); 3291 } 3292 } 3293 bremfree(bp); 3294 bp->b_flags |= B_ASYNC; 3295 /* 3296 * default (old) behavior, writing out only one block 3297 * 3298 * XXX returns b_bufsize instead of b_bcount for nwritten? 3299 */ 3300 nwritten = bp->b_bufsize; 3301 (void) bwrite(bp); 3302 3303 return (nwritten); 3304 } 3305 3306 /* 3307 * getnewbuf_kva: 3308 * 3309 * Allocate KVA for an empty buf header according to gbflags. 3310 */ 3311 static int 3312 getnewbuf_kva(struct buf *bp, int gbflags, int maxsize) 3313 { 3314 3315 if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_UNMAPPED) { 3316 /* 3317 * In order to keep fragmentation sane we only allocate kva 3318 * in BKVASIZE chunks. XXX with vmem we can do page size. 3319 */ 3320 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK; 3321 3322 if (maxsize != bp->b_kvasize && 3323 bufkva_alloc(bp, maxsize, gbflags)) 3324 return (ENOSPC); 3325 } 3326 return (0); 3327 } 3328 3329 /* 3330 * getnewbuf: 3331 * 3332 * Find and initialize a new buffer header, freeing up existing buffers 3333 * in the bufqueues as necessary. The new buffer is returned locked. 3334 * 3335 * We block if: 3336 * We have insufficient buffer headers 3337 * We have insufficient buffer space 3338 * buffer_arena is too fragmented ( space reservation fails ) 3339 * If we have to flush dirty buffers ( but we try to avoid this ) 3340 * 3341 * The caller is responsible for releasing the reserved bufspace after 3342 * allocbuf() is called. 3343 */ 3344 static struct buf * 3345 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int maxsize, int gbflags) 3346 { 3347 struct bufdomain *bd; 3348 struct buf *bp; 3349 bool metadata, reserved; 3350 3351 bp = NULL; 3352 KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3353 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3354 if (!unmapped_buf_allowed) 3355 gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3356 3357 if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 || 3358 vp->v_type == VCHR) 3359 metadata = true; 3360 else 3361 metadata = false; 3362 if (vp == NULL) 3363 bd = &bdomain[0]; 3364 else 3365 bd = &bdomain[vp->v_bufobj.bo_domain]; 3366 3367 counter_u64_add(getnewbufcalls, 1); 3368 reserved = false; 3369 do { 3370 if (reserved == false && 3371 bufspace_reserve(bd, maxsize, metadata) != 0) { 3372 counter_u64_add(getnewbufrestarts, 1); 3373 continue; 3374 } 3375 reserved = true; 3376 if ((bp = buf_alloc(bd)) == NULL) { 3377 counter_u64_add(getnewbufrestarts, 1); 3378 continue; 3379 } 3380 if (getnewbuf_kva(bp, gbflags, maxsize) == 0) 3381 return (bp); 3382 break; 3383 } while (buf_recycle(bd, false) == 0); 3384 3385 if (reserved) 3386 bufspace_release(bd, maxsize); 3387 if (bp != NULL) { 3388 bp->b_flags |= B_INVAL; 3389 brelse(bp); 3390 } 3391 bufspace_wait(bd, vp, gbflags, slpflag, slptimeo); 3392 3393 return (NULL); 3394 } 3395 3396 /* 3397 * buf_daemon: 3398 * 3399 * buffer flushing daemon. Buffers are normally flushed by the 3400 * update daemon but if it cannot keep up this process starts to 3401 * take the load in an attempt to prevent getnewbuf() from blocking. 3402 */ 3403 static struct kproc_desc buf_kp = { 3404 "bufdaemon", 3405 buf_daemon, 3406 &bufdaemonproc 3407 }; 3408 SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp); 3409 3410 static int 3411 buf_flush(struct vnode *vp, struct bufdomain *bd, int target) 3412 { 3413 int flushed; 3414 3415 flushed = flushbufqueues(vp, bd, target, 0); 3416 if (flushed == 0) { 3417 /* 3418 * Could not find any buffers without rollback 3419 * dependencies, so just write the first one 3420 * in the hopes of eventually making progress. 3421 */ 3422 if (vp != NULL && target > 2) 3423 target /= 2; 3424 flushbufqueues(vp, bd, target, 1); 3425 } 3426 return (flushed); 3427 } 3428 3429 static void 3430 buf_daemon_shutdown(void *arg __unused, int howto __unused) 3431 { 3432 int error; 3433 3434 if (KERNEL_PANICKED()) 3435 return; 3436 3437 mtx_lock(&bdlock); 3438 bd_shutdown = true; 3439 wakeup(&bd_request); 3440 error = msleep(&bd_shutdown, &bdlock, 0, "buf_daemon_shutdown", 3441 60 * hz); 3442 mtx_unlock(&bdlock); 3443 if (error != 0) 3444 printf("bufdaemon wait error: %d\n", error); 3445 } 3446 3447 static void 3448 buf_daemon(void) 3449 { 3450 struct bufdomain *bd; 3451 int speedupreq; 3452 int lodirty; 3453 int i; 3454 3455 /* 3456 * This process needs to be suspended prior to shutdown sync. 3457 */ 3458 EVENTHANDLER_REGISTER(shutdown_pre_sync, buf_daemon_shutdown, NULL, 3459 SHUTDOWN_PRI_LAST + 100); 3460 3461 /* 3462 * Start the buf clean daemons as children threads. 3463 */ 3464 for (i = 0 ; i < buf_domains; i++) { 3465 int error; 3466 3467 error = kthread_add((void (*)(void *))bufspace_daemon, 3468 &bdomain[i], curproc, NULL, 0, 0, "bufspacedaemon-%d", i); 3469 if (error) 3470 panic("error %d spawning bufspace daemon", error); 3471 } 3472 3473 /* 3474 * This process is allowed to take the buffer cache to the limit 3475 */ 3476 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED; 3477 mtx_lock(&bdlock); 3478 while (!bd_shutdown) { 3479 bd_request = 0; 3480 mtx_unlock(&bdlock); 3481 3482 /* 3483 * Save speedupreq for this pass and reset to capture new 3484 * requests. 3485 */ 3486 speedupreq = bd_speedupreq; 3487 bd_speedupreq = 0; 3488 3489 /* 3490 * Flush each domain sequentially according to its level and 3491 * the speedup request. 3492 */ 3493 for (i = 0; i < buf_domains; i++) { 3494 bd = &bdomain[i]; 3495 if (speedupreq) 3496 lodirty = bd->bd_numdirtybuffers / 2; 3497 else 3498 lodirty = bd->bd_lodirtybuffers; 3499 while (bd->bd_numdirtybuffers > lodirty) { 3500 if (buf_flush(NULL, bd, 3501 bd->bd_numdirtybuffers - lodirty) == 0) 3502 break; 3503 kern_yield(PRI_USER); 3504 } 3505 } 3506 3507 /* 3508 * Only clear bd_request if we have reached our low water 3509 * mark. The buf_daemon normally waits 1 second and 3510 * then incrementally flushes any dirty buffers that have 3511 * built up, within reason. 3512 * 3513 * If we were unable to hit our low water mark and couldn't 3514 * find any flushable buffers, we sleep for a short period 3515 * to avoid endless loops on unlockable buffers. 3516 */ 3517 mtx_lock(&bdlock); 3518 if (bd_shutdown) 3519 break; 3520 if (BIT_EMPTY(BUF_DOMAINS, &bdlodirty)) { 3521 /* 3522 * We reached our low water mark, reset the 3523 * request and sleep until we are needed again. 3524 * The sleep is just so the suspend code works. 3525 */ 3526 bd_request = 0; 3527 /* 3528 * Do an extra wakeup in case dirty threshold 3529 * changed via sysctl and the explicit transition 3530 * out of shortfall was missed. 3531 */ 3532 bdirtywakeup(); 3533 if (runningbufspace <= lorunningspace) 3534 runningwakeup(); 3535 msleep(&bd_request, &bdlock, PVM, "psleep", hz); 3536 } else { 3537 /* 3538 * We couldn't find any flushable dirty buffers but 3539 * still have too many dirty buffers, we 3540 * have to sleep and try again. (rare) 3541 */ 3542 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10); 3543 } 3544 } 3545 wakeup(&bd_shutdown); 3546 mtx_unlock(&bdlock); 3547 kthread_exit(); 3548 } 3549 3550 /* 3551 * flushbufqueues: 3552 * 3553 * Try to flush a buffer in the dirty queue. We must be careful to 3554 * free up B_INVAL buffers instead of write them, which NFS is 3555 * particularly sensitive to. 3556 */ 3557 static int flushwithdeps = 0; 3558 SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW | CTLFLAG_STATS, 3559 &flushwithdeps, 0, 3560 "Number of buffers flushed with dependencies that require rollbacks"); 3561 3562 static int 3563 flushbufqueues(struct vnode *lvp, struct bufdomain *bd, int target, 3564 int flushdeps) 3565 { 3566 struct bufqueue *bq; 3567 struct buf *sentinel; 3568 struct vnode *vp; 3569 struct mount *mp; 3570 struct buf *bp; 3571 int hasdeps; 3572 int flushed; 3573 int error; 3574 bool unlock; 3575 3576 flushed = 0; 3577 bq = &bd->bd_dirtyq; 3578 bp = NULL; 3579 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO); 3580 sentinel->b_qindex = QUEUE_SENTINEL; 3581 BQ_LOCK(bq); 3582 TAILQ_INSERT_HEAD(&bq->bq_queue, sentinel, b_freelist); 3583 BQ_UNLOCK(bq); 3584 while (flushed != target) { 3585 maybe_yield(); 3586 BQ_LOCK(bq); 3587 bp = TAILQ_NEXT(sentinel, b_freelist); 3588 if (bp != NULL) { 3589 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3590 TAILQ_INSERT_AFTER(&bq->bq_queue, bp, sentinel, 3591 b_freelist); 3592 } else { 3593 BQ_UNLOCK(bq); 3594 break; 3595 } 3596 /* 3597 * Skip sentinels inserted by other invocations of the 3598 * flushbufqueues(), taking care to not reorder them. 3599 * 3600 * Only flush the buffers that belong to the 3601 * vnode locked by the curthread. 3602 */ 3603 if (bp->b_qindex == QUEUE_SENTINEL || (lvp != NULL && 3604 bp->b_vp != lvp)) { 3605 BQ_UNLOCK(bq); 3606 continue; 3607 } 3608 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 3609 BQ_UNLOCK(bq); 3610 if (error != 0) 3611 continue; 3612 3613 /* 3614 * BKGRDINPROG can only be set with the buf and bufobj 3615 * locks both held. We tolerate a race to clear it here. 3616 */ 3617 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 || 3618 (bp->b_flags & B_DELWRI) == 0) { 3619 BUF_UNLOCK(bp); 3620 continue; 3621 } 3622 if (bp->b_flags & B_INVAL) { 3623 bremfreef(bp); 3624 brelse(bp); 3625 flushed++; 3626 continue; 3627 } 3628 3629 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) { 3630 if (flushdeps == 0) { 3631 BUF_UNLOCK(bp); 3632 continue; 3633 } 3634 hasdeps = 1; 3635 } else 3636 hasdeps = 0; 3637 /* 3638 * We must hold the lock on a vnode before writing 3639 * one of its buffers. Otherwise we may confuse, or 3640 * in the case of a snapshot vnode, deadlock the 3641 * system. 3642 * 3643 * The lock order here is the reverse of the normal 3644 * of vnode followed by buf lock. This is ok because 3645 * the NOWAIT will prevent deadlock. 3646 */ 3647 vp = bp->b_vp; 3648 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { 3649 BUF_UNLOCK(bp); 3650 continue; 3651 } 3652 if (lvp == NULL) { 3653 unlock = true; 3654 error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); 3655 } else { 3656 ASSERT_VOP_LOCKED(vp, "getbuf"); 3657 unlock = false; 3658 error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : 3659 vn_lock(vp, LK_TRYUPGRADE); 3660 } 3661 if (error == 0) { 3662 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", 3663 bp, bp->b_vp, bp->b_flags); 3664 if (curproc == bufdaemonproc) { 3665 vfs_bio_awrite(bp); 3666 } else { 3667 bremfree(bp); 3668 bwrite(bp); 3669 counter_u64_add(notbufdflushes, 1); 3670 } 3671 vn_finished_write(mp); 3672 if (unlock) 3673 VOP_UNLOCK(vp); 3674 flushwithdeps += hasdeps; 3675 flushed++; 3676 3677 /* 3678 * Sleeping on runningbufspace while holding 3679 * vnode lock leads to deadlock. 3680 */ 3681 if (curproc == bufdaemonproc && 3682 runningbufspace > hirunningspace) 3683 waitrunningbufspace(); 3684 continue; 3685 } 3686 vn_finished_write(mp); 3687 BUF_UNLOCK(bp); 3688 } 3689 BQ_LOCK(bq); 3690 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3691 BQ_UNLOCK(bq); 3692 free(sentinel, M_TEMP); 3693 return (flushed); 3694 } 3695 3696 /* 3697 * Check to see if a block is currently memory resident. 3698 */ 3699 struct buf * 3700 incore(struct bufobj *bo, daddr_t blkno) 3701 { 3702 return (gbincore_unlocked(bo, blkno)); 3703 } 3704 3705 /* 3706 * Returns true if no I/O is needed to access the 3707 * associated VM object. This is like incore except 3708 * it also hunts around in the VM system for the data. 3709 */ 3710 bool 3711 inmem(struct vnode * vp, daddr_t blkno) 3712 { 3713 vm_object_t obj; 3714 vm_offset_t toff, tinc, size; 3715 vm_page_t m, n; 3716 vm_ooffset_t off; 3717 int valid; 3718 3719 ASSERT_VOP_LOCKED(vp, "inmem"); 3720 3721 if (incore(&vp->v_bufobj, blkno)) 3722 return (true); 3723 if (vp->v_mount == NULL) 3724 return (false); 3725 obj = vp->v_object; 3726 if (obj == NULL) 3727 return (false); 3728 3729 size = PAGE_SIZE; 3730 if (size > vp->v_mount->mnt_stat.f_iosize) 3731 size = vp->v_mount->mnt_stat.f_iosize; 3732 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 3733 3734 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 3735 m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3736 recheck: 3737 if (m == NULL) 3738 return (false); 3739 3740 tinc = size; 3741 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 3742 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 3743 /* 3744 * Consider page validity only if page mapping didn't change 3745 * during the check. 3746 */ 3747 valid = vm_page_is_valid(m, 3748 (vm_offset_t)((toff + off) & PAGE_MASK), tinc); 3749 n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3750 if (m != n) { 3751 m = n; 3752 goto recheck; 3753 } 3754 if (!valid) 3755 return (false); 3756 } 3757 return (true); 3758 } 3759 3760 /* 3761 * Set the dirty range for a buffer based on the status of the dirty 3762 * bits in the pages comprising the buffer. The range is limited 3763 * to the size of the buffer. 3764 * 3765 * Tell the VM system that the pages associated with this buffer 3766 * are clean. This is used for delayed writes where the data is 3767 * going to go to disk eventually without additional VM intevention. 3768 * 3769 * Note that while we only really need to clean through to b_bcount, we 3770 * just go ahead and clean through to b_bufsize. 3771 */ 3772 static void 3773 vfs_clean_pages_dirty_buf(struct buf *bp) 3774 { 3775 vm_ooffset_t foff, noff, eoff; 3776 vm_page_t m; 3777 int i; 3778 3779 if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0) 3780 return; 3781 3782 foff = bp->b_offset; 3783 KASSERT(bp->b_offset != NOOFFSET, 3784 ("vfs_clean_pages_dirty_buf: no buffer offset")); 3785 3786 vfs_busy_pages_acquire(bp); 3787 vfs_setdirty_range(bp); 3788 for (i = 0; i < bp->b_npages; i++) { 3789 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3790 eoff = noff; 3791 if (eoff > bp->b_offset + bp->b_bufsize) 3792 eoff = bp->b_offset + bp->b_bufsize; 3793 m = bp->b_pages[i]; 3794 vfs_page_set_validclean(bp, foff, m); 3795 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */ 3796 foff = noff; 3797 } 3798 vfs_busy_pages_release(bp); 3799 } 3800 3801 static void 3802 vfs_setdirty_range(struct buf *bp) 3803 { 3804 vm_offset_t boffset; 3805 vm_offset_t eoffset; 3806 int i; 3807 3808 /* 3809 * test the pages to see if they have been modified directly 3810 * by users through the VM system. 3811 */ 3812 for (i = 0; i < bp->b_npages; i++) 3813 vm_page_test_dirty(bp->b_pages[i]); 3814 3815 /* 3816 * Calculate the encompassing dirty range, boffset and eoffset, 3817 * (eoffset - boffset) bytes. 3818 */ 3819 3820 for (i = 0; i < bp->b_npages; i++) { 3821 if (bp->b_pages[i]->dirty) 3822 break; 3823 } 3824 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3825 3826 for (i = bp->b_npages - 1; i >= 0; --i) { 3827 if (bp->b_pages[i]->dirty) { 3828 break; 3829 } 3830 } 3831 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3832 3833 /* 3834 * Fit it to the buffer. 3835 */ 3836 3837 if (eoffset > bp->b_bcount) 3838 eoffset = bp->b_bcount; 3839 3840 /* 3841 * If we have a good dirty range, merge with the existing 3842 * dirty range. 3843 */ 3844 3845 if (boffset < eoffset) { 3846 if (bp->b_dirtyoff > boffset) 3847 bp->b_dirtyoff = boffset; 3848 if (bp->b_dirtyend < eoffset) 3849 bp->b_dirtyend = eoffset; 3850 } 3851 } 3852 3853 /* 3854 * Allocate the KVA mapping for an existing buffer. 3855 * If an unmapped buffer is provided but a mapped buffer is requested, take 3856 * also care to properly setup mappings between pages and KVA. 3857 */ 3858 static void 3859 bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags) 3860 { 3861 int bsize, maxsize, need_mapping, need_kva; 3862 off_t offset; 3863 3864 need_mapping = bp->b_data == unmapped_buf && 3865 (gbflags & GB_UNMAPPED) == 0; 3866 need_kva = bp->b_kvabase == unmapped_buf && 3867 bp->b_data == unmapped_buf && 3868 (gbflags & GB_KVAALLOC) != 0; 3869 if (!need_mapping && !need_kva) 3870 return; 3871 3872 BUF_CHECK_UNMAPPED(bp); 3873 3874 if (need_mapping && bp->b_kvabase != unmapped_buf) { 3875 /* 3876 * Buffer is not mapped, but the KVA was already 3877 * reserved at the time of the instantiation. Use the 3878 * allocated space. 3879 */ 3880 goto has_addr; 3881 } 3882 3883 /* 3884 * Calculate the amount of the address space we would reserve 3885 * if the buffer was mapped. 3886 */ 3887 bsize = vn_isdisk(bp->b_vp) ? DEV_BSIZE : bp->b_bufobj->bo_bsize; 3888 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 3889 offset = blkno * bsize; 3890 maxsize = size + (offset & PAGE_MASK); 3891 maxsize = imax(maxsize, bsize); 3892 3893 while (bufkva_alloc(bp, maxsize, gbflags) != 0) { 3894 if ((gbflags & GB_NOWAIT_BD) != 0) { 3895 /* 3896 * XXXKIB: defragmentation cannot 3897 * succeed, not sure what else to do. 3898 */ 3899 panic("GB_NOWAIT_BD and GB_UNMAPPED %p", bp); 3900 } 3901 counter_u64_add(mappingrestarts, 1); 3902 bufspace_wait(bufdomain(bp), bp->b_vp, gbflags, 0, 0); 3903 } 3904 has_addr: 3905 if (need_mapping) { 3906 /* b_offset is handled by bpmap_qenter. */ 3907 bp->b_data = bp->b_kvabase; 3908 BUF_CHECK_MAPPED(bp); 3909 bpmap_qenter(bp); 3910 } 3911 } 3912 3913 struct buf * 3914 getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo, 3915 int flags) 3916 { 3917 struct buf *bp; 3918 int error; 3919 3920 error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp); 3921 if (error != 0) 3922 return (NULL); 3923 return (bp); 3924 } 3925 3926 /* 3927 * getblkx: 3928 * 3929 * Get a block given a specified block and offset into a file/device. 3930 * The buffers B_DONE bit will be cleared on return, making it almost 3931 * ready for an I/O initiation. B_INVAL may or may not be set on 3932 * return. The caller should clear B_INVAL prior to initiating a 3933 * READ. 3934 * 3935 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for 3936 * an existing buffer. 3937 * 3938 * For a VMIO buffer, B_CACHE is modified according to the backing VM. 3939 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set 3940 * and then cleared based on the backing VM. If the previous buffer is 3941 * non-0-sized but invalid, B_CACHE will be cleared. 3942 * 3943 * If getblk() must create a new buffer, the new buffer is returned with 3944 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which 3945 * case it is returned with B_INVAL clear and B_CACHE set based on the 3946 * backing VM. 3947 * 3948 * getblk() also forces a bwrite() for any B_DELWRI buffer whose 3949 * B_CACHE bit is clear. 3950 * 3951 * What this means, basically, is that the caller should use B_CACHE to 3952 * determine whether the buffer is fully valid or not and should clear 3953 * B_INVAL prior to issuing a read. If the caller intends to validate 3954 * the buffer by loading its data area with something, the caller needs 3955 * to clear B_INVAL. If the caller does this without issuing an I/O, 3956 * the caller should set B_CACHE ( as an optimization ), else the caller 3957 * should issue the I/O and biodone() will set B_CACHE if the I/O was 3958 * a write attempt or if it was a successful read. If the caller 3959 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR 3960 * prior to issuing the READ. biodone() will *not* clear B_INVAL. 3961 * 3962 * The blkno parameter is the logical block being requested. Normally 3963 * the mapping of logical block number to disk block address is done 3964 * by calling VOP_BMAP(). However, if the mapping is already known, the 3965 * disk block address can be passed using the dblkno parameter. If the 3966 * disk block address is not known, then the same value should be passed 3967 * for blkno and dblkno. 3968 */ 3969 int 3970 getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag, 3971 int slptimeo, int flags, struct buf **bpp) 3972 { 3973 struct buf *bp; 3974 struct bufobj *bo; 3975 daddr_t d_blkno; 3976 int bsize, error, maxsize, vmio; 3977 off_t offset; 3978 3979 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size); 3980 KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3981 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3982 if (vp->v_type != VCHR) 3983 ASSERT_VOP_LOCKED(vp, "getblk"); 3984 if (size > maxbcachebuf) { 3985 printf("getblkx: size(%d) > maxbcachebuf(%d)\n", size, 3986 maxbcachebuf); 3987 return (EIO); 3988 } 3989 if (!unmapped_buf_allowed) 3990 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3991 3992 bo = &vp->v_bufobj; 3993 d_blkno = dblkno; 3994 3995 /* Attempt lockless lookup first. */ 3996 bp = gbincore_unlocked(bo, blkno); 3997 if (bp == NULL) { 3998 /* 3999 * With GB_NOCREAT we must be sure about not finding the buffer 4000 * as it may have been reassigned during unlocked lookup. 4001 * If BO_NONSTERILE is still unset, no reassign has occurred. 4002 */ 4003 if ((flags & GB_NOCREAT) != 0) { 4004 /* Ensure bo_flag is loaded after gbincore_unlocked. */ 4005 atomic_thread_fence_acq(); 4006 if ((bo->bo_flag & BO_NONSTERILE) == 0) 4007 return (EEXIST); 4008 goto loop; 4009 } 4010 goto newbuf_unlocked; 4011 } 4012 4013 error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL, "getblku", 0, 4014 0); 4015 if (error != 0) { 4016 KASSERT(error == EBUSY, 4017 ("getblk: unexpected error %d from buf try-lock", error)); 4018 /* 4019 * We failed a buf try-lock. 4020 * 4021 * With GB_LOCK_NOWAIT, just return, rather than taking the 4022 * bufobj interlock and trying again, since we would probably 4023 * fail again anyway. This is okay even if the buf's identity 4024 * changed and we contended on the wrong lock, as changing 4025 * identity itself requires the buf lock, and we could have 4026 * contended on the right lock. 4027 */ 4028 if ((flags & GB_LOCK_NOWAIT) != 0) 4029 return (error); 4030 goto loop; 4031 } 4032 4033 /* Verify buf identify has not changed since lookup. */ 4034 if (bp->b_bufobj == bo && bp->b_lblkno == blkno) 4035 goto foundbuf_fastpath; 4036 4037 /* It changed, fallback to locked lookup. */ 4038 BUF_UNLOCK_RAW(bp); 4039 4040 /* As above, with GB_LOCK_NOWAIT, just return. */ 4041 if ((flags & GB_LOCK_NOWAIT) != 0) 4042 return (EBUSY); 4043 4044 loop: 4045 BO_RLOCK(bo); 4046 bp = gbincore(bo, blkno); 4047 if (bp != NULL) { 4048 int lockflags; 4049 4050 /* 4051 * Buffer is in-core. If the buffer is not busy nor managed, 4052 * it must be on a queue. 4053 */ 4054 lockflags = LK_EXCLUSIVE | LK_INTERLOCK | 4055 ((flags & GB_LOCK_NOWAIT) != 0 ? LK_NOWAIT : LK_SLEEPFAIL); 4056 #ifdef WITNESS 4057 lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0; 4058 #endif 4059 4060 error = BUF_TIMELOCK(bp, lockflags, 4061 BO_LOCKPTR(bo), "getblk", slpflag, slptimeo); 4062 4063 /* 4064 * If we slept and got the lock we have to restart in case 4065 * the buffer changed identities. 4066 */ 4067 if (error == ENOLCK) 4068 goto loop; 4069 /* We timed out or were interrupted. */ 4070 else if (error != 0) 4071 return (error); 4072 4073 foundbuf_fastpath: 4074 /* If recursed, assume caller knows the rules. */ 4075 if (BUF_LOCKRECURSED(bp)) 4076 goto end; 4077 4078 /* 4079 * The buffer is locked. B_CACHE is cleared if the buffer is 4080 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set 4081 * and for a VMIO buffer B_CACHE is adjusted according to the 4082 * backing VM cache. 4083 */ 4084 if (bp->b_flags & B_INVAL) 4085 bp->b_flags &= ~B_CACHE; 4086 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0) 4087 bp->b_flags |= B_CACHE; 4088 if (bp->b_flags & B_MANAGED) 4089 MPASS(bp->b_qindex == QUEUE_NONE); 4090 else 4091 bremfree(bp); 4092 4093 /* 4094 * check for size inconsistencies for non-VMIO case. 4095 */ 4096 if (bp->b_bcount != size) { 4097 if ((bp->b_flags & B_VMIO) == 0 || 4098 (size > bp->b_kvasize)) { 4099 if (bp->b_flags & B_DELWRI) { 4100 bp->b_flags |= B_NOCACHE; 4101 bwrite(bp); 4102 } else { 4103 if (LIST_EMPTY(&bp->b_dep)) { 4104 bp->b_flags |= B_RELBUF; 4105 brelse(bp); 4106 } else { 4107 bp->b_flags |= B_NOCACHE; 4108 bwrite(bp); 4109 } 4110 } 4111 goto loop; 4112 } 4113 } 4114 4115 /* 4116 * Handle the case of unmapped buffer which should 4117 * become mapped, or the buffer for which KVA 4118 * reservation is requested. 4119 */ 4120 bp_unmapped_get_kva(bp, blkno, size, flags); 4121 4122 /* 4123 * If the size is inconsistent in the VMIO case, we can resize 4124 * the buffer. This might lead to B_CACHE getting set or 4125 * cleared. If the size has not changed, B_CACHE remains 4126 * unchanged from its previous state. 4127 */ 4128 allocbuf(bp, size); 4129 4130 KASSERT(bp->b_offset != NOOFFSET, 4131 ("getblk: no buffer offset")); 4132 4133 /* 4134 * A buffer with B_DELWRI set and B_CACHE clear must 4135 * be committed before we can return the buffer in 4136 * order to prevent the caller from issuing a read 4137 * ( due to B_CACHE not being set ) and overwriting 4138 * it. 4139 * 4140 * Most callers, including NFS and FFS, need this to 4141 * operate properly either because they assume they 4142 * can issue a read if B_CACHE is not set, or because 4143 * ( for example ) an uncached B_DELWRI might loop due 4144 * to softupdates re-dirtying the buffer. In the latter 4145 * case, B_CACHE is set after the first write completes, 4146 * preventing further loops. 4147 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE 4148 * above while extending the buffer, we cannot allow the 4149 * buffer to remain with B_CACHE set after the write 4150 * completes or it will represent a corrupt state. To 4151 * deal with this we set B_NOCACHE to scrap the buffer 4152 * after the write. 4153 * 4154 * We might be able to do something fancy, like setting 4155 * B_CACHE in bwrite() except if B_DELWRI is already set, 4156 * so the below call doesn't set B_CACHE, but that gets real 4157 * confusing. This is much easier. 4158 */ 4159 4160 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) { 4161 bp->b_flags |= B_NOCACHE; 4162 bwrite(bp); 4163 goto loop; 4164 } 4165 bp->b_flags &= ~B_DONE; 4166 } else { 4167 /* 4168 * Buffer is not in-core, create new buffer. The buffer 4169 * returned by getnewbuf() is locked. Note that the returned 4170 * buffer is also considered valid (not marked B_INVAL). 4171 */ 4172 BO_RUNLOCK(bo); 4173 newbuf_unlocked: 4174 /* 4175 * If the user does not want us to create the buffer, bail out 4176 * here. 4177 */ 4178 if (flags & GB_NOCREAT) 4179 return (EEXIST); 4180 4181 bsize = vn_isdisk(vp) ? DEV_BSIZE : bo->bo_bsize; 4182 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 4183 offset = blkno * bsize; 4184 vmio = vp->v_object != NULL; 4185 if (vmio) { 4186 maxsize = size + (offset & PAGE_MASK); 4187 if (maxsize > maxbcachebuf) { 4188 printf( 4189 "getblkx: maxsize(%d) > maxbcachebuf(%d)\n", 4190 maxsize, maxbcachebuf); 4191 return (EIO); 4192 } 4193 } else { 4194 maxsize = size; 4195 /* Do not allow non-VMIO notmapped buffers. */ 4196 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 4197 } 4198 maxsize = imax(maxsize, bsize); 4199 if ((flags & GB_NOSPARSE) != 0 && vmio && 4200 !vn_isdisk(vp)) { 4201 error = VOP_BMAP(vp, blkno, NULL, &d_blkno, 0, 0); 4202 KASSERT(error != EOPNOTSUPP, 4203 ("GB_NOSPARSE from fs not supporting bmap, vp %p", 4204 vp)); 4205 if (error != 0) 4206 return (error); 4207 if (d_blkno == -1) 4208 return (EJUSTRETURN); 4209 } 4210 4211 bp = getnewbuf(vp, slpflag, slptimeo, maxsize, flags); 4212 if (bp == NULL) { 4213 if (slpflag || slptimeo) 4214 return (ETIMEDOUT); 4215 /* 4216 * XXX This is here until the sleep path is diagnosed 4217 * enough to work under very low memory conditions. 4218 * 4219 * There's an issue on low memory, 4BSD+non-preempt 4220 * systems (eg MIPS routers with 32MB RAM) where buffer 4221 * exhaustion occurs without sleeping for buffer 4222 * reclaimation. This just sticks in a loop and 4223 * constantly attempts to allocate a buffer, which 4224 * hits exhaustion and tries to wakeup bufdaemon. 4225 * This never happens because we never yield. 4226 * 4227 * The real solution is to identify and fix these cases 4228 * so we aren't effectively busy-waiting in a loop 4229 * until the reclaimation path has cycles to run. 4230 */ 4231 kern_yield(PRI_USER); 4232 goto loop; 4233 } 4234 4235 /* 4236 * 4237 * Insert the buffer into the hash, so that it can 4238 * be found by incore. 4239 * 4240 * We don't hold the bufobj interlock while allocating the new 4241 * buffer. Consequently, we can race on buffer creation. This 4242 * can be a problem whether the vnode is locked or not. If the 4243 * buffer is created out from under us, we have to throw away 4244 * the one we just created. 4245 */ 4246 bp->b_lblkno = blkno; 4247 bp->b_blkno = d_blkno; 4248 bp->b_offset = offset; 4249 error = bgetvp(vp, bp); 4250 if (error != 0) { 4251 KASSERT(error == EEXIST, 4252 ("getblk: unexpected error %d from bgetvp", 4253 error)); 4254 bp->b_flags |= B_INVAL; 4255 bufspace_release(bufdomain(bp), maxsize); 4256 brelse(bp); 4257 goto loop; 4258 } 4259 4260 /* 4261 * set B_VMIO bit. allocbuf() the buffer bigger. Since the 4262 * buffer size starts out as 0, B_CACHE will be set by 4263 * allocbuf() for the VMIO case prior to it testing the 4264 * backing store for validity. 4265 */ 4266 4267 if (vmio) { 4268 bp->b_flags |= B_VMIO; 4269 KASSERT(vp->v_object == bp->b_bufobj->bo_object, 4270 ("ARGH! different b_bufobj->bo_object %p %p %p\n", 4271 bp, vp->v_object, bp->b_bufobj->bo_object)); 4272 } else { 4273 bp->b_flags &= ~B_VMIO; 4274 KASSERT(bp->b_bufobj->bo_object == NULL, 4275 ("ARGH! has b_bufobj->bo_object %p %p\n", 4276 bp, bp->b_bufobj->bo_object)); 4277 BUF_CHECK_MAPPED(bp); 4278 } 4279 4280 allocbuf(bp, size); 4281 bufspace_release(bufdomain(bp), maxsize); 4282 bp->b_flags &= ~B_DONE; 4283 } 4284 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp); 4285 end: 4286 buf_track(bp, __func__); 4287 KASSERT(bp->b_bufobj == bo, 4288 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo)); 4289 *bpp = bp; 4290 return (0); 4291 } 4292 4293 /* 4294 * Get an empty, disassociated buffer of given size. The buffer is initially 4295 * set to B_INVAL. 4296 */ 4297 struct buf * 4298 geteblk(int size, int flags) 4299 { 4300 struct buf *bp; 4301 int maxsize; 4302 4303 maxsize = (size + BKVAMASK) & ~BKVAMASK; 4304 while ((bp = getnewbuf(NULL, 0, 0, maxsize, flags)) == NULL) { 4305 if ((flags & GB_NOWAIT_BD) && 4306 (curthread->td_pflags & TDP_BUFNEED) != 0) 4307 return (NULL); 4308 } 4309 allocbuf(bp, size); 4310 bufspace_release(bufdomain(bp), maxsize); 4311 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 4312 return (bp); 4313 } 4314 4315 /* 4316 * Truncate the backing store for a non-vmio buffer. 4317 */ 4318 static void 4319 vfs_nonvmio_truncate(struct buf *bp, int newbsize) 4320 { 4321 4322 if (bp->b_flags & B_MALLOC) { 4323 /* 4324 * malloced buffers are not shrunk 4325 */ 4326 if (newbsize == 0) { 4327 bufmallocadjust(bp, 0); 4328 free(bp->b_data, M_BIOBUF); 4329 bp->b_data = bp->b_kvabase; 4330 bp->b_flags &= ~B_MALLOC; 4331 } 4332 return; 4333 } 4334 vm_hold_free_pages(bp, newbsize); 4335 bufspace_adjust(bp, newbsize); 4336 } 4337 4338 /* 4339 * Extend the backing for a non-VMIO buffer. 4340 */ 4341 static void 4342 vfs_nonvmio_extend(struct buf *bp, int newbsize) 4343 { 4344 caddr_t origbuf; 4345 int origbufsize; 4346 4347 /* 4348 * We only use malloced memory on the first allocation. 4349 * and revert to page-allocated memory when the buffer 4350 * grows. 4351 * 4352 * There is a potential smp race here that could lead 4353 * to bufmallocspace slightly passing the max. It 4354 * is probably extremely rare and not worth worrying 4355 * over. 4356 */ 4357 if (bp->b_bufsize == 0 && newbsize <= PAGE_SIZE/2 && 4358 bufmallocspace < maxbufmallocspace) { 4359 bp->b_data = malloc(newbsize, M_BIOBUF, M_WAITOK); 4360 bp->b_flags |= B_MALLOC; 4361 bufmallocadjust(bp, newbsize); 4362 return; 4363 } 4364 4365 /* 4366 * If the buffer is growing on its other-than-first 4367 * allocation then we revert to the page-allocation 4368 * scheme. 4369 */ 4370 origbuf = NULL; 4371 origbufsize = 0; 4372 if (bp->b_flags & B_MALLOC) { 4373 origbuf = bp->b_data; 4374 origbufsize = bp->b_bufsize; 4375 bp->b_data = bp->b_kvabase; 4376 bufmallocadjust(bp, 0); 4377 bp->b_flags &= ~B_MALLOC; 4378 newbsize = round_page(newbsize); 4379 } 4380 vm_hold_load_pages(bp, (vm_offset_t) bp->b_data + bp->b_bufsize, 4381 (vm_offset_t) bp->b_data + newbsize); 4382 if (origbuf != NULL) { 4383 bcopy(origbuf, bp->b_data, origbufsize); 4384 free(origbuf, M_BIOBUF); 4385 } 4386 bufspace_adjust(bp, newbsize); 4387 } 4388 4389 /* 4390 * This code constitutes the buffer memory from either anonymous system 4391 * memory (in the case of non-VMIO operations) or from an associated 4392 * VM object (in the case of VMIO operations). This code is able to 4393 * resize a buffer up or down. 4394 * 4395 * Note that this code is tricky, and has many complications to resolve 4396 * deadlock or inconsistent data situations. Tread lightly!!! 4397 * There are B_CACHE and B_DELWRI interactions that must be dealt with by 4398 * the caller. Calling this code willy nilly can result in the loss of data. 4399 * 4400 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with 4401 * B_CACHE for the non-VMIO case. 4402 */ 4403 int 4404 allocbuf(struct buf *bp, int size) 4405 { 4406 int newbsize; 4407 4408 if (bp->b_bcount == size) 4409 return (1); 4410 4411 KASSERT(bp->b_kvasize == 0 || bp->b_kvasize >= size, 4412 ("allocbuf: buffer too small %p %#x %#x", 4413 bp, bp->b_kvasize, size)); 4414 4415 newbsize = roundup2(size, DEV_BSIZE); 4416 if ((bp->b_flags & B_VMIO) == 0) { 4417 if ((bp->b_flags & B_MALLOC) == 0) 4418 newbsize = round_page(newbsize); 4419 /* 4420 * Just get anonymous memory from the kernel. Don't 4421 * mess with B_CACHE. 4422 */ 4423 if (newbsize < bp->b_bufsize) 4424 vfs_nonvmio_truncate(bp, newbsize); 4425 else if (newbsize > bp->b_bufsize) 4426 vfs_nonvmio_extend(bp, newbsize); 4427 } else { 4428 int desiredpages; 4429 4430 desiredpages = size == 0 ? 0 : 4431 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 4432 4433 KASSERT((bp->b_flags & B_MALLOC) == 0, 4434 ("allocbuf: VMIO buffer can't be malloced %p", bp)); 4435 4436 /* 4437 * Set B_CACHE initially if buffer is 0 length or will become 4438 * 0-length. 4439 */ 4440 if (size == 0 || bp->b_bufsize == 0) 4441 bp->b_flags |= B_CACHE; 4442 4443 if (newbsize < bp->b_bufsize) 4444 vfs_vmio_truncate(bp, desiredpages); 4445 /* XXX This looks as if it should be newbsize > b_bufsize */ 4446 else if (size > bp->b_bcount) 4447 vfs_vmio_extend(bp, desiredpages, size); 4448 bufspace_adjust(bp, newbsize); 4449 } 4450 bp->b_bcount = size; /* requested buffer size. */ 4451 return (1); 4452 } 4453 4454 extern int inflight_transient_maps; 4455 4456 static struct bio_queue nondump_bios; 4457 4458 void 4459 biodone(struct bio *bp) 4460 { 4461 struct mtx *mtxp; 4462 void (*done)(struct bio *); 4463 vm_offset_t start, end; 4464 4465 biotrack(bp, __func__); 4466 4467 /* 4468 * Avoid completing I/O when dumping after a panic since that may 4469 * result in a deadlock in the filesystem or pager code. Note that 4470 * this doesn't affect dumps that were started manually since we aim 4471 * to keep the system usable after it has been resumed. 4472 */ 4473 if (__predict_false(dumping && SCHEDULER_STOPPED())) { 4474 TAILQ_INSERT_HEAD(&nondump_bios, bp, bio_queue); 4475 return; 4476 } 4477 if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { 4478 bp->bio_flags &= ~BIO_TRANSIENT_MAPPING; 4479 bp->bio_flags |= BIO_UNMAPPED; 4480 start = trunc_page((vm_offset_t)bp->bio_data); 4481 end = round_page((vm_offset_t)bp->bio_data + bp->bio_length); 4482 bp->bio_data = unmapped_buf; 4483 pmap_qremove(start, atop(end - start)); 4484 vmem_free(transient_arena, start, end - start); 4485 atomic_add_int(&inflight_transient_maps, -1); 4486 } 4487 done = bp->bio_done; 4488 /* 4489 * The check for done == biodone is to allow biodone to be 4490 * used as a bio_done routine. 4491 */ 4492 if (done == NULL || done == biodone) { 4493 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4494 mtx_lock(mtxp); 4495 bp->bio_flags |= BIO_DONE; 4496 wakeup(bp); 4497 mtx_unlock(mtxp); 4498 } else 4499 done(bp); 4500 } 4501 4502 /* 4503 * Wait for a BIO to finish. 4504 */ 4505 int 4506 biowait(struct bio *bp, const char *wmesg) 4507 { 4508 struct mtx *mtxp; 4509 4510 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4511 mtx_lock(mtxp); 4512 while ((bp->bio_flags & BIO_DONE) == 0) 4513 msleep(bp, mtxp, PRIBIO, wmesg, 0); 4514 mtx_unlock(mtxp); 4515 if (bp->bio_error != 0) 4516 return (bp->bio_error); 4517 if (!(bp->bio_flags & BIO_ERROR)) 4518 return (0); 4519 return (EIO); 4520 } 4521 4522 void 4523 biofinish(struct bio *bp, struct devstat *stat, int error) 4524 { 4525 4526 if (error) { 4527 bp->bio_error = error; 4528 bp->bio_flags |= BIO_ERROR; 4529 } 4530 if (stat != NULL) 4531 devstat_end_transaction_bio(stat, bp); 4532 biodone(bp); 4533 } 4534 4535 #if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING) 4536 void 4537 biotrack_buf(struct bio *bp, const char *location) 4538 { 4539 4540 buf_track(bp->bio_track_bp, location); 4541 } 4542 #endif 4543 4544 /* 4545 * bufwait: 4546 * 4547 * Wait for buffer I/O completion, returning error status. The buffer 4548 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR 4549 * error and cleared. 4550 */ 4551 int 4552 bufwait(struct buf *bp) 4553 { 4554 if (bp->b_iocmd == BIO_READ) 4555 bwait(bp, PRIBIO, "biord"); 4556 else 4557 bwait(bp, PRIBIO, "biowr"); 4558 if (bp->b_flags & B_EINTR) { 4559 bp->b_flags &= ~B_EINTR; 4560 return (EINTR); 4561 } 4562 if (bp->b_ioflags & BIO_ERROR) { 4563 return (bp->b_error ? bp->b_error : EIO); 4564 } else { 4565 return (0); 4566 } 4567 } 4568 4569 /* 4570 * bufdone: 4571 * 4572 * Finish I/O on a buffer, optionally calling a completion function. 4573 * This is usually called from an interrupt so process blocking is 4574 * not allowed. 4575 * 4576 * biodone is also responsible for setting B_CACHE in a B_VMIO bp. 4577 * In a non-VMIO bp, B_CACHE will be set on the next getblk() 4578 * assuming B_INVAL is clear. 4579 * 4580 * For the VMIO case, we set B_CACHE if the op was a read and no 4581 * read error occurred, or if the op was a write. B_CACHE is never 4582 * set if the buffer is invalid or otherwise uncacheable. 4583 * 4584 * bufdone does not mess with B_INVAL, allowing the I/O routine or the 4585 * initiator to leave B_INVAL set to brelse the buffer out of existence 4586 * in the biodone routine. 4587 */ 4588 void 4589 bufdone(struct buf *bp) 4590 { 4591 struct bufobj *dropobj; 4592 void (*biodone)(struct buf *); 4593 4594 buf_track(bp, __func__); 4595 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 4596 dropobj = NULL; 4597 4598 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp)); 4599 4600 runningbufwakeup(bp); 4601 if (bp->b_iocmd == BIO_WRITE) 4602 dropobj = bp->b_bufobj; 4603 /* call optional completion function if requested */ 4604 if (bp->b_iodone != NULL) { 4605 biodone = bp->b_iodone; 4606 bp->b_iodone = NULL; 4607 (*biodone) (bp); 4608 if (dropobj) 4609 bufobj_wdrop(dropobj); 4610 return; 4611 } 4612 if (bp->b_flags & B_VMIO) { 4613 /* 4614 * Set B_CACHE if the op was a normal read and no error 4615 * occurred. B_CACHE is set for writes in the b*write() 4616 * routines. 4617 */ 4618 if (bp->b_iocmd == BIO_READ && 4619 !(bp->b_flags & (B_INVAL|B_NOCACHE)) && 4620 !(bp->b_ioflags & BIO_ERROR)) 4621 bp->b_flags |= B_CACHE; 4622 vfs_vmio_iodone(bp); 4623 } 4624 if (!LIST_EMPTY(&bp->b_dep)) 4625 buf_complete(bp); 4626 if ((bp->b_flags & B_CKHASH) != 0) { 4627 KASSERT(bp->b_iocmd == BIO_READ, 4628 ("bufdone: b_iocmd %d not BIO_READ", bp->b_iocmd)); 4629 KASSERT(buf_mapped(bp), ("bufdone: bp %p not mapped", bp)); 4630 (*bp->b_ckhashcalc)(bp); 4631 } 4632 /* 4633 * For asynchronous completions, release the buffer now. The brelse 4634 * will do a wakeup there if necessary - so no need to do a wakeup 4635 * here in the async case. The sync case always needs to do a wakeup. 4636 */ 4637 if (bp->b_flags & B_ASYNC) { 4638 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || 4639 (bp->b_ioflags & BIO_ERROR)) 4640 brelse(bp); 4641 else 4642 bqrelse(bp); 4643 } else 4644 bdone(bp); 4645 if (dropobj) 4646 bufobj_wdrop(dropobj); 4647 } 4648 4649 /* 4650 * This routine is called in lieu of iodone in the case of 4651 * incomplete I/O. This keeps the busy status for pages 4652 * consistent. 4653 */ 4654 void 4655 vfs_unbusy_pages(struct buf *bp) 4656 { 4657 int i; 4658 vm_object_t obj; 4659 vm_page_t m; 4660 4661 runningbufwakeup(bp); 4662 if (!(bp->b_flags & B_VMIO)) 4663 return; 4664 4665 obj = bp->b_bufobj->bo_object; 4666 for (i = 0; i < bp->b_npages; i++) { 4667 m = bp->b_pages[i]; 4668 if (m == bogus_page) { 4669 m = vm_page_relookup(obj, OFF_TO_IDX(bp->b_offset) + i); 4670 if (!m) 4671 panic("vfs_unbusy_pages: page missing\n"); 4672 bp->b_pages[i] = m; 4673 if (buf_mapped(bp)) { 4674 BUF_CHECK_MAPPED(bp); 4675 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4676 bp->b_pages, bp->b_npages); 4677 } else 4678 BUF_CHECK_UNMAPPED(bp); 4679 } 4680 vm_page_sunbusy(m); 4681 } 4682 vm_object_pip_wakeupn(obj, bp->b_npages); 4683 } 4684 4685 /* 4686 * vfs_page_set_valid: 4687 * 4688 * Set the valid bits in a page based on the supplied offset. The 4689 * range is restricted to the buffer's size. 4690 * 4691 * This routine is typically called after a read completes. 4692 */ 4693 static void 4694 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4695 { 4696 vm_ooffset_t eoff; 4697 4698 /* 4699 * Compute the end offset, eoff, such that [off, eoff) does not span a 4700 * page boundary and eoff is not greater than the end of the buffer. 4701 * The end of the buffer, in this case, is our file EOF, not the 4702 * allocation size of the buffer. 4703 */ 4704 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK; 4705 if (eoff > bp->b_offset + bp->b_bcount) 4706 eoff = bp->b_offset + bp->b_bcount; 4707 4708 /* 4709 * Set valid range. This is typically the entire buffer and thus the 4710 * entire page. 4711 */ 4712 if (eoff > off) 4713 vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off); 4714 } 4715 4716 /* 4717 * vfs_page_set_validclean: 4718 * 4719 * Set the valid bits and clear the dirty bits in a page based on the 4720 * supplied offset. The range is restricted to the buffer's size. 4721 */ 4722 static void 4723 vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4724 { 4725 vm_ooffset_t soff, eoff; 4726 4727 /* 4728 * Start and end offsets in buffer. eoff - soff may not cross a 4729 * page boundary or cross the end of the buffer. The end of the 4730 * buffer, in this case, is our file EOF, not the allocation size 4731 * of the buffer. 4732 */ 4733 soff = off; 4734 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4735 if (eoff > bp->b_offset + bp->b_bcount) 4736 eoff = bp->b_offset + bp->b_bcount; 4737 4738 /* 4739 * Set valid range. This is typically the entire buffer and thus the 4740 * entire page. 4741 */ 4742 if (eoff > soff) { 4743 vm_page_set_validclean( 4744 m, 4745 (vm_offset_t) (soff & PAGE_MASK), 4746 (vm_offset_t) (eoff - soff) 4747 ); 4748 } 4749 } 4750 4751 /* 4752 * Acquire a shared busy on all pages in the buf. 4753 */ 4754 void 4755 vfs_busy_pages_acquire(struct buf *bp) 4756 { 4757 int i; 4758 4759 for (i = 0; i < bp->b_npages; i++) 4760 vm_page_busy_acquire(bp->b_pages[i], VM_ALLOC_SBUSY); 4761 } 4762 4763 void 4764 vfs_busy_pages_release(struct buf *bp) 4765 { 4766 int i; 4767 4768 for (i = 0; i < bp->b_npages; i++) 4769 vm_page_sunbusy(bp->b_pages[i]); 4770 } 4771 4772 /* 4773 * This routine is called before a device strategy routine. 4774 * It is used to tell the VM system that paging I/O is in 4775 * progress, and treat the pages associated with the buffer 4776 * almost as being exclusive busy. Also the object paging_in_progress 4777 * flag is handled to make sure that the object doesn't become 4778 * inconsistent. 4779 * 4780 * Since I/O has not been initiated yet, certain buffer flags 4781 * such as BIO_ERROR or B_INVAL may be in an inconsistent state 4782 * and should be ignored. 4783 */ 4784 void 4785 vfs_busy_pages(struct buf *bp, int clear_modify) 4786 { 4787 vm_object_t obj; 4788 vm_ooffset_t foff; 4789 vm_page_t m; 4790 int i; 4791 bool bogus; 4792 4793 if (!(bp->b_flags & B_VMIO)) 4794 return; 4795 4796 obj = bp->b_bufobj->bo_object; 4797 foff = bp->b_offset; 4798 KASSERT(bp->b_offset != NOOFFSET, 4799 ("vfs_busy_pages: no buffer offset")); 4800 if ((bp->b_flags & B_CLUSTER) == 0) { 4801 vm_object_pip_add(obj, bp->b_npages); 4802 vfs_busy_pages_acquire(bp); 4803 } 4804 if (bp->b_bufsize != 0) 4805 vfs_setdirty_range(bp); 4806 bogus = false; 4807 for (i = 0; i < bp->b_npages; i++) { 4808 m = bp->b_pages[i]; 4809 vm_page_assert_sbusied(m); 4810 4811 /* 4812 * When readying a buffer for a read ( i.e 4813 * clear_modify == 0 ), it is important to do 4814 * bogus_page replacement for valid pages in 4815 * partially instantiated buffers. Partially 4816 * instantiated buffers can, in turn, occur when 4817 * reconstituting a buffer from its VM backing store 4818 * base. We only have to do this if B_CACHE is 4819 * clear ( which causes the I/O to occur in the 4820 * first place ). The replacement prevents the read 4821 * I/O from overwriting potentially dirty VM-backed 4822 * pages. XXX bogus page replacement is, uh, bogus. 4823 * It may not work properly with small-block devices. 4824 * We need to find a better way. 4825 */ 4826 if (clear_modify) { 4827 pmap_remove_write(m); 4828 vfs_page_set_validclean(bp, foff, m); 4829 } else if (vm_page_all_valid(m) && 4830 (bp->b_flags & B_CACHE) == 0) { 4831 bp->b_pages[i] = bogus_page; 4832 bogus = true; 4833 } 4834 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4835 } 4836 if (bogus && buf_mapped(bp)) { 4837 BUF_CHECK_MAPPED(bp); 4838 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4839 bp->b_pages, bp->b_npages); 4840 } 4841 } 4842 4843 /* 4844 * vfs_bio_set_valid: 4845 * 4846 * Set the range within the buffer to valid. The range is 4847 * relative to the beginning of the buffer, b_offset. Note that 4848 * b_offset itself may be offset from the beginning of the first 4849 * page. 4850 */ 4851 void 4852 vfs_bio_set_valid(struct buf *bp, int base, int size) 4853 { 4854 int i, n; 4855 vm_page_t m; 4856 4857 if (!(bp->b_flags & B_VMIO)) 4858 return; 4859 4860 /* 4861 * Fixup base to be relative to beginning of first page. 4862 * Set initial n to be the maximum number of bytes in the 4863 * first page that can be validated. 4864 */ 4865 base += (bp->b_offset & PAGE_MASK); 4866 n = PAGE_SIZE - (base & PAGE_MASK); 4867 4868 /* 4869 * Busy may not be strictly necessary here because the pages are 4870 * unlikely to be fully valid and the vnode lock will synchronize 4871 * their access via getpages. It is grabbed for consistency with 4872 * other page validation. 4873 */ 4874 vfs_busy_pages_acquire(bp); 4875 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4876 m = bp->b_pages[i]; 4877 if (n > size) 4878 n = size; 4879 vm_page_set_valid_range(m, base & PAGE_MASK, n); 4880 base += n; 4881 size -= n; 4882 n = PAGE_SIZE; 4883 } 4884 vfs_busy_pages_release(bp); 4885 } 4886 4887 /* 4888 * vfs_bio_clrbuf: 4889 * 4890 * If the specified buffer is a non-VMIO buffer, clear the entire 4891 * buffer. If the specified buffer is a VMIO buffer, clear and 4892 * validate only the previously invalid portions of the buffer. 4893 * This routine essentially fakes an I/O, so we need to clear 4894 * BIO_ERROR and B_INVAL. 4895 * 4896 * Note that while we only theoretically need to clear through b_bcount, 4897 * we go ahead and clear through b_bufsize. 4898 */ 4899 void 4900 vfs_bio_clrbuf(struct buf *bp) 4901 { 4902 int i, j, sa, ea, slide, zbits; 4903 vm_page_bits_t mask; 4904 4905 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) { 4906 clrbuf(bp); 4907 return; 4908 } 4909 bp->b_flags &= ~B_INVAL; 4910 bp->b_ioflags &= ~BIO_ERROR; 4911 vfs_busy_pages_acquire(bp); 4912 sa = bp->b_offset & PAGE_MASK; 4913 slide = 0; 4914 for (i = 0; i < bp->b_npages; i++, sa = 0) { 4915 slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize); 4916 ea = slide & PAGE_MASK; 4917 if (ea == 0) 4918 ea = PAGE_SIZE; 4919 if (bp->b_pages[i] == bogus_page) 4920 continue; 4921 j = sa / DEV_BSIZE; 4922 zbits = (sizeof(vm_page_bits_t) * NBBY) - 4923 (ea - sa) / DEV_BSIZE; 4924 mask = (VM_PAGE_BITS_ALL >> zbits) << j; 4925 if ((bp->b_pages[i]->valid & mask) == mask) 4926 continue; 4927 if ((bp->b_pages[i]->valid & mask) == 0) 4928 pmap_zero_page_area(bp->b_pages[i], sa, ea - sa); 4929 else { 4930 for (; sa < ea; sa += DEV_BSIZE, j++) { 4931 if ((bp->b_pages[i]->valid & (1 << j)) == 0) { 4932 pmap_zero_page_area(bp->b_pages[i], 4933 sa, DEV_BSIZE); 4934 } 4935 } 4936 } 4937 vm_page_set_valid_range(bp->b_pages[i], j * DEV_BSIZE, 4938 roundup2(ea - sa, DEV_BSIZE)); 4939 } 4940 vfs_busy_pages_release(bp); 4941 bp->b_resid = 0; 4942 } 4943 4944 void 4945 vfs_bio_bzero_buf(struct buf *bp, int base, int size) 4946 { 4947 vm_page_t m; 4948 int i, n; 4949 4950 if (buf_mapped(bp)) { 4951 BUF_CHECK_MAPPED(bp); 4952 bzero(bp->b_data + base, size); 4953 } else { 4954 BUF_CHECK_UNMAPPED(bp); 4955 n = PAGE_SIZE - (base & PAGE_MASK); 4956 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4957 m = bp->b_pages[i]; 4958 if (n > size) 4959 n = size; 4960 pmap_zero_page_area(m, base & PAGE_MASK, n); 4961 base += n; 4962 size -= n; 4963 n = PAGE_SIZE; 4964 } 4965 } 4966 } 4967 4968 /* 4969 * Update buffer flags based on I/O request parameters, optionally releasing the 4970 * buffer. If it's VMIO or direct I/O, the buffer pages are released to the VM, 4971 * where they may be placed on a page queue (VMIO) or freed immediately (direct 4972 * I/O). Otherwise the buffer is released to the cache. 4973 */ 4974 static void 4975 b_io_dismiss(struct buf *bp, int ioflag, bool release) 4976 { 4977 4978 KASSERT((ioflag & IO_NOREUSE) == 0 || (ioflag & IO_VMIO) != 0, 4979 ("buf %p non-VMIO noreuse", bp)); 4980 4981 if ((ioflag & IO_DIRECT) != 0) 4982 bp->b_flags |= B_DIRECT; 4983 if ((ioflag & IO_EXT) != 0) 4984 bp->b_xflags |= BX_ALTDATA; 4985 if ((ioflag & (IO_VMIO | IO_DIRECT)) != 0 && LIST_EMPTY(&bp->b_dep)) { 4986 bp->b_flags |= B_RELBUF; 4987 if ((ioflag & IO_NOREUSE) != 0) 4988 bp->b_flags |= B_NOREUSE; 4989 if (release) 4990 brelse(bp); 4991 } else if (release) 4992 bqrelse(bp); 4993 } 4994 4995 void 4996 vfs_bio_brelse(struct buf *bp, int ioflag) 4997 { 4998 4999 b_io_dismiss(bp, ioflag, true); 5000 } 5001 5002 void 5003 vfs_bio_set_flags(struct buf *bp, int ioflag) 5004 { 5005 5006 b_io_dismiss(bp, ioflag, false); 5007 } 5008 5009 /* 5010 * vm_hold_load_pages and vm_hold_free_pages get pages into 5011 * a buffers address space. The pages are anonymous and are 5012 * not associated with a file object. 5013 */ 5014 static void 5015 vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to) 5016 { 5017 vm_offset_t pg; 5018 vm_page_t p; 5019 int index; 5020 5021 BUF_CHECK_MAPPED(bp); 5022 5023 to = round_page(to); 5024 from = round_page(from); 5025 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 5026 MPASS((bp->b_flags & B_MAXPHYS) == 0); 5027 KASSERT(to - from <= maxbcachebuf, 5028 ("vm_hold_load_pages too large %p %#jx %#jx %u", 5029 bp, (uintmax_t)from, (uintmax_t)to, maxbcachebuf)); 5030 5031 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 5032 /* 5033 * note: must allocate system pages since blocking here 5034 * could interfere with paging I/O, no matter which 5035 * process we are. 5036 */ 5037 p = vm_page_alloc_noobj(VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | 5038 VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT) | VM_ALLOC_WAITOK); 5039 pmap_qenter(pg, &p, 1); 5040 bp->b_pages[index] = p; 5041 } 5042 bp->b_npages = index; 5043 } 5044 5045 /* Return pages associated with this buf to the vm system */ 5046 static void 5047 vm_hold_free_pages(struct buf *bp, int newbsize) 5048 { 5049 vm_offset_t from; 5050 vm_page_t p; 5051 int index, newnpages; 5052 5053 BUF_CHECK_MAPPED(bp); 5054 5055 from = round_page((vm_offset_t)bp->b_data + newbsize); 5056 newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 5057 if (bp->b_npages > newnpages) 5058 pmap_qremove(from, bp->b_npages - newnpages); 5059 for (index = newnpages; index < bp->b_npages; index++) { 5060 p = bp->b_pages[index]; 5061 bp->b_pages[index] = NULL; 5062 vm_page_unwire_noq(p); 5063 vm_page_free(p); 5064 } 5065 bp->b_npages = newnpages; 5066 } 5067 5068 /* 5069 * Map an IO request into kernel virtual address space. 5070 * 5071 * All requests are (re)mapped into kernel VA space. 5072 * Notice that we use b_bufsize for the size of the buffer 5073 * to be mapped. b_bcount might be modified by the driver. 5074 * 5075 * Note that even if the caller determines that the address space should 5076 * be valid, a race or a smaller-file mapped into a larger space may 5077 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST 5078 * check the return value. 5079 * 5080 * This function only works with pager buffers. 5081 */ 5082 int 5083 vmapbuf(struct buf *bp, void *uaddr, size_t len, int mapbuf) 5084 { 5085 vm_prot_t prot; 5086 int pidx; 5087 5088 MPASS((bp->b_flags & B_MAXPHYS) != 0); 5089 prot = VM_PROT_READ; 5090 if (bp->b_iocmd == BIO_READ) 5091 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 5092 pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 5093 (vm_offset_t)uaddr, len, prot, bp->b_pages, PBUF_PAGES); 5094 if (pidx < 0) 5095 return (-1); 5096 bp->b_bufsize = len; 5097 bp->b_npages = pidx; 5098 bp->b_offset = ((vm_offset_t)uaddr) & PAGE_MASK; 5099 if (mapbuf || !unmapped_buf_allowed) { 5100 pmap_qenter((vm_offset_t)bp->b_kvabase, bp->b_pages, pidx); 5101 bp->b_data = bp->b_kvabase + bp->b_offset; 5102 } else 5103 bp->b_data = unmapped_buf; 5104 return (0); 5105 } 5106 5107 /* 5108 * Free the io map PTEs associated with this IO operation. 5109 * We also invalidate the TLB entries and restore the original b_addr. 5110 * 5111 * This function only works with pager buffers. 5112 */ 5113 void 5114 vunmapbuf(struct buf *bp) 5115 { 5116 int npages; 5117 5118 npages = bp->b_npages; 5119 if (buf_mapped(bp)) 5120 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages); 5121 vm_page_unhold_pages(bp->b_pages, npages); 5122 5123 bp->b_data = unmapped_buf; 5124 } 5125 5126 void 5127 bdone(struct buf *bp) 5128 { 5129 struct mtx *mtxp; 5130 5131 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5132 mtx_lock(mtxp); 5133 bp->b_flags |= B_DONE; 5134 wakeup(bp); 5135 mtx_unlock(mtxp); 5136 } 5137 5138 void 5139 bwait(struct buf *bp, u_char pri, const char *wchan) 5140 { 5141 struct mtx *mtxp; 5142 5143 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5144 mtx_lock(mtxp); 5145 while ((bp->b_flags & B_DONE) == 0) 5146 msleep(bp, mtxp, pri, wchan, 0); 5147 mtx_unlock(mtxp); 5148 } 5149 5150 int 5151 bufsync(struct bufobj *bo, int waitfor) 5152 { 5153 5154 return (VOP_FSYNC(bo2vnode(bo), waitfor, curthread)); 5155 } 5156 5157 void 5158 bufstrategy(struct bufobj *bo, struct buf *bp) 5159 { 5160 int i __unused; 5161 struct vnode *vp; 5162 5163 vp = bp->b_vp; 5164 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy")); 5165 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 5166 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp)); 5167 i = VOP_STRATEGY(vp, bp); 5168 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp)); 5169 } 5170 5171 /* 5172 * Initialize a struct bufobj before use. Memory is assumed zero filled. 5173 */ 5174 void 5175 bufobj_init(struct bufobj *bo, void *private) 5176 { 5177 static volatile int bufobj_cleanq; 5178 5179 bo->bo_domain = 5180 atomic_fetchadd_int(&bufobj_cleanq, 1) % buf_domains; 5181 rw_init(BO_LOCKPTR(bo), "bufobj interlock"); 5182 bo->bo_private = private; 5183 TAILQ_INIT(&bo->bo_clean.bv_hd); 5184 pctrie_init(&bo->bo_clean.bv_root); 5185 TAILQ_INIT(&bo->bo_dirty.bv_hd); 5186 pctrie_init(&bo->bo_dirty.bv_root); 5187 } 5188 5189 void 5190 bufobj_wrefl(struct bufobj *bo) 5191 { 5192 5193 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5194 ASSERT_BO_WLOCKED(bo); 5195 bo->bo_numoutput++; 5196 } 5197 5198 void 5199 bufobj_wref(struct bufobj *bo) 5200 { 5201 5202 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5203 BO_LOCK(bo); 5204 bo->bo_numoutput++; 5205 BO_UNLOCK(bo); 5206 } 5207 5208 void 5209 bufobj_wdrop(struct bufobj *bo) 5210 { 5211 5212 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop")); 5213 BO_LOCK(bo); 5214 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count")); 5215 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) { 5216 bo->bo_flag &= ~BO_WWAIT; 5217 wakeup(&bo->bo_numoutput); 5218 } 5219 BO_UNLOCK(bo); 5220 } 5221 5222 int 5223 bufobj_wwait(struct bufobj *bo, int slpflag, int timeo) 5224 { 5225 int error; 5226 5227 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait")); 5228 ASSERT_BO_WLOCKED(bo); 5229 error = 0; 5230 while (bo->bo_numoutput) { 5231 bo->bo_flag |= BO_WWAIT; 5232 error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo), 5233 slpflag | (PRIBIO + 1), "bo_wwait", timeo); 5234 if (error) 5235 break; 5236 } 5237 return (error); 5238 } 5239 5240 /* 5241 * Set bio_data or bio_ma for struct bio from the struct buf. 5242 */ 5243 void 5244 bdata2bio(struct buf *bp, struct bio *bip) 5245 { 5246 5247 if (!buf_mapped(bp)) { 5248 KASSERT(unmapped_buf_allowed, ("unmapped")); 5249 bip->bio_ma = bp->b_pages; 5250 bip->bio_ma_n = bp->b_npages; 5251 bip->bio_data = unmapped_buf; 5252 bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK; 5253 bip->bio_flags |= BIO_UNMAPPED; 5254 KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) / 5255 PAGE_SIZE == bp->b_npages, 5256 ("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset, 5257 (long long)bip->bio_length, bip->bio_ma_n)); 5258 } else { 5259 bip->bio_data = bp->b_data; 5260 bip->bio_ma = NULL; 5261 } 5262 } 5263 5264 struct memdesc 5265 memdesc_bio(struct bio *bio) 5266 { 5267 if ((bio->bio_flags & BIO_VLIST) != 0) 5268 return (memdesc_vlist((struct bus_dma_segment *)bio->bio_data, 5269 bio->bio_ma_n)); 5270 5271 if ((bio->bio_flags & BIO_UNMAPPED) != 0) 5272 return (memdesc_vmpages(bio->bio_ma, bio->bio_bcount, 5273 bio->bio_ma_offset)); 5274 5275 return (memdesc_vaddr(bio->bio_data, bio->bio_bcount)); 5276 } 5277 5278 static int buf_pager_relbuf; 5279 SYSCTL_INT(_vfs, OID_AUTO, buf_pager_relbuf, CTLFLAG_RWTUN, 5280 &buf_pager_relbuf, 0, 5281 "Make buffer pager release buffers after reading"); 5282 5283 /* 5284 * The buffer pager. It uses buffer reads to validate pages. 5285 * 5286 * In contrast to the generic local pager from vm/vnode_pager.c, this 5287 * pager correctly and easily handles volumes where the underlying 5288 * device block size is greater than the machine page size. The 5289 * buffer cache transparently extends the requested page run to be 5290 * aligned at the block boundary, and does the necessary bogus page 5291 * replacements in the addends to avoid obliterating already valid 5292 * pages. 5293 * 5294 * The only non-trivial issue is that the exclusive busy state for 5295 * pages, which is assumed by the vm_pager_getpages() interface, is 5296 * incompatible with the VMIO buffer cache's desire to share-busy the 5297 * pages. This function performs a trivial downgrade of the pages' 5298 * state before reading buffers, and a less trivial upgrade from the 5299 * shared-busy to excl-busy state after the read. 5300 */ 5301 int 5302 vfs_bio_getpages(struct vnode *vp, vm_page_t *ma, int count, 5303 int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno, 5304 vbg_get_blksize_t get_blksize) 5305 { 5306 vm_page_t m; 5307 vm_object_t object; 5308 struct buf *bp; 5309 struct mount *mp; 5310 daddr_t lbn, lbnp; 5311 vm_ooffset_t la, lb, poff, poffe; 5312 long bo_bs, bsize; 5313 int br_flags, error, i, pgsin, pgsin_a, pgsin_b; 5314 bool redo, lpart; 5315 5316 object = vp->v_object; 5317 mp = vp->v_mount; 5318 error = 0; 5319 la = IDX_TO_OFF(ma[count - 1]->pindex); 5320 if (la >= object->un_pager.vnp.vnp_size) 5321 return (VM_PAGER_BAD); 5322 5323 /* 5324 * Change the meaning of la from where the last requested page starts 5325 * to where it ends, because that's the end of the requested region 5326 * and the start of the potential read-ahead region. 5327 */ 5328 la += PAGE_SIZE; 5329 lpart = la > object->un_pager.vnp.vnp_size; 5330 error = get_blksize(vp, get_lblkno(vp, IDX_TO_OFF(ma[0]->pindex)), 5331 &bo_bs); 5332 if (error != 0) 5333 return (VM_PAGER_ERROR); 5334 5335 /* 5336 * Calculate read-ahead, behind and total pages. 5337 */ 5338 pgsin = count; 5339 lb = IDX_TO_OFF(ma[0]->pindex); 5340 pgsin_b = OFF_TO_IDX(lb - rounddown2(lb, bo_bs)); 5341 pgsin += pgsin_b; 5342 if (rbehind != NULL) 5343 *rbehind = pgsin_b; 5344 pgsin_a = OFF_TO_IDX(roundup2(la, bo_bs) - la); 5345 if (la + IDX_TO_OFF(pgsin_a) >= object->un_pager.vnp.vnp_size) 5346 pgsin_a = OFF_TO_IDX(roundup2(object->un_pager.vnp.vnp_size, 5347 PAGE_SIZE) - la); 5348 pgsin += pgsin_a; 5349 if (rahead != NULL) 5350 *rahead = pgsin_a; 5351 VM_CNT_INC(v_vnodein); 5352 VM_CNT_ADD(v_vnodepgsin, pgsin); 5353 5354 br_flags = (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) 5355 != 0) ? GB_UNMAPPED : 0; 5356 again: 5357 for (i = 0; i < count; i++) { 5358 if (ma[i] != bogus_page) 5359 vm_page_busy_downgrade(ma[i]); 5360 } 5361 5362 lbnp = -1; 5363 for (i = 0; i < count; i++) { 5364 m = ma[i]; 5365 if (m == bogus_page) 5366 continue; 5367 5368 /* 5369 * Pages are shared busy and the object lock is not 5370 * owned, which together allow for the pages' 5371 * invalidation. The racy test for validity avoids 5372 * useless creation of the buffer for the most typical 5373 * case when invalidation is not used in redo or for 5374 * parallel read. The shared->excl upgrade loop at 5375 * the end of the function catches the race in a 5376 * reliable way (protected by the object lock). 5377 */ 5378 if (vm_page_all_valid(m)) 5379 continue; 5380 5381 poff = IDX_TO_OFF(m->pindex); 5382 poffe = MIN(poff + PAGE_SIZE, object->un_pager.vnp.vnp_size); 5383 for (; poff < poffe; poff += bsize) { 5384 lbn = get_lblkno(vp, poff); 5385 if (lbn == lbnp) 5386 goto next_page; 5387 lbnp = lbn; 5388 5389 error = get_blksize(vp, lbn, &bsize); 5390 if (error == 0) 5391 error = bread_gb(vp, lbn, bsize, 5392 curthread->td_ucred, br_flags, &bp); 5393 if (error != 0) 5394 goto end_pages; 5395 if (bp->b_rcred == curthread->td_ucred) { 5396 crfree(bp->b_rcred); 5397 bp->b_rcred = NOCRED; 5398 } 5399 if (LIST_EMPTY(&bp->b_dep)) { 5400 /* 5401 * Invalidation clears m->valid, but 5402 * may leave B_CACHE flag if the 5403 * buffer existed at the invalidation 5404 * time. In this case, recycle the 5405 * buffer to do real read on next 5406 * bread() after redo. 5407 * 5408 * Otherwise B_RELBUF is not strictly 5409 * necessary, enable to reduce buf 5410 * cache pressure. 5411 */ 5412 if (buf_pager_relbuf || 5413 !vm_page_all_valid(m)) 5414 bp->b_flags |= B_RELBUF; 5415 5416 bp->b_flags &= ~B_NOCACHE; 5417 brelse(bp); 5418 } else { 5419 bqrelse(bp); 5420 } 5421 } 5422 KASSERT(1 /* racy, enable for debugging */ || 5423 vm_page_all_valid(m) || i == count - 1, 5424 ("buf %d %p invalid", i, m)); 5425 if (i == count - 1 && lpart) { 5426 if (!vm_page_none_valid(m) && 5427 !vm_page_all_valid(m)) 5428 vm_page_zero_invalid(m, TRUE); 5429 } 5430 next_page:; 5431 } 5432 end_pages: 5433 5434 redo = false; 5435 for (i = 0; i < count; i++) { 5436 if (ma[i] == bogus_page) 5437 continue; 5438 if (vm_page_busy_tryupgrade(ma[i]) == 0) { 5439 vm_page_sunbusy(ma[i]); 5440 ma[i] = vm_page_grab_unlocked(object, ma[i]->pindex, 5441 VM_ALLOC_NORMAL); 5442 } 5443 5444 /* 5445 * Since the pages were only sbusy while neither the 5446 * buffer nor the object lock was held by us, or 5447 * reallocated while vm_page_grab() slept for busy 5448 * relinguish, they could have been invalidated. 5449 * Recheck the valid bits and re-read as needed. 5450 * 5451 * Note that the last page is made fully valid in the 5452 * read loop, and partial validity for the page at 5453 * index count - 1 could mean that the page was 5454 * invalidated or removed, so we must restart for 5455 * safety as well. 5456 */ 5457 if (!vm_page_all_valid(ma[i])) 5458 redo = true; 5459 } 5460 if (redo && error == 0) 5461 goto again; 5462 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 5463 } 5464 5465 #include "opt_ddb.h" 5466 #ifdef DDB 5467 #include <ddb/ddb.h> 5468 5469 /* DDB command to show buffer data */ 5470 DB_SHOW_COMMAND(buffer, db_show_buffer) 5471 { 5472 /* get args */ 5473 struct buf *bp = (struct buf *)addr; 5474 #ifdef FULL_BUF_TRACKING 5475 uint32_t i, j; 5476 #endif 5477 5478 if (!have_addr) { 5479 db_printf("usage: show buffer <addr>\n"); 5480 return; 5481 } 5482 5483 db_printf("buf at %p\n", bp); 5484 db_printf("b_flags = 0x%b, b_xflags = 0x%b\n", 5485 (u_int)bp->b_flags, PRINT_BUF_FLAGS, 5486 (u_int)bp->b_xflags, PRINT_BUF_XFLAGS); 5487 db_printf("b_vflags = 0x%b, b_ioflags = 0x%b\n", 5488 (u_int)bp->b_vflags, PRINT_BUF_VFLAGS, 5489 (u_int)bp->b_ioflags, PRINT_BIO_FLAGS); 5490 db_printf( 5491 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n" 5492 "b_bufobj = %p, b_data = %p\n" 5493 "b_blkno = %jd, b_lblkno = %jd, b_vp = %p, b_dep = %p\n", 5494 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 5495 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno, 5496 (intmax_t)bp->b_lblkno, bp->b_vp, bp->b_dep.lh_first); 5497 db_printf("b_kvabase = %p, b_kvasize = %d\n", 5498 bp->b_kvabase, bp->b_kvasize); 5499 if (bp->b_npages) { 5500 int i; 5501 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 5502 for (i = 0; i < bp->b_npages; i++) { 5503 vm_page_t m; 5504 m = bp->b_pages[i]; 5505 if (m != NULL) 5506 db_printf("(%p, 0x%lx, 0x%lx)", m->object, 5507 (u_long)m->pindex, 5508 (u_long)VM_PAGE_TO_PHYS(m)); 5509 else 5510 db_printf("( ??? )"); 5511 if ((i + 1) < bp->b_npages) 5512 db_printf(","); 5513 } 5514 db_printf("\n"); 5515 } 5516 BUF_LOCKPRINTINFO(bp); 5517 #if defined(FULL_BUF_TRACKING) 5518 db_printf("b_io_tracking: b_io_tcnt = %u\n", bp->b_io_tcnt); 5519 5520 i = bp->b_io_tcnt % BUF_TRACKING_SIZE; 5521 for (j = 1; j <= BUF_TRACKING_SIZE; j++) { 5522 if (bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)] == NULL) 5523 continue; 5524 db_printf(" %2u: %s\n", j, 5525 bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)]); 5526 } 5527 #elif defined(BUF_TRACKING) 5528 db_printf("b_io_tracking: %s\n", bp->b_io_tracking); 5529 #endif 5530 } 5531 5532 DB_SHOW_COMMAND_FLAGS(bufqueues, bufqueues, DB_CMD_MEMSAFE) 5533 { 5534 struct bufdomain *bd; 5535 struct buf *bp; 5536 long total; 5537 int i, j, cnt; 5538 5539 db_printf("bqempty: %d\n", bqempty.bq_len); 5540 5541 for (i = 0; i < buf_domains; i++) { 5542 bd = &bdomain[i]; 5543 db_printf("Buf domain %d\n", i); 5544 db_printf("\tfreebufs\t%d\n", bd->bd_freebuffers); 5545 db_printf("\tlofreebufs\t%d\n", bd->bd_lofreebuffers); 5546 db_printf("\thifreebufs\t%d\n", bd->bd_hifreebuffers); 5547 db_printf("\n"); 5548 db_printf("\tbufspace\t%ld\n", bd->bd_bufspace); 5549 db_printf("\tmaxbufspace\t%ld\n", bd->bd_maxbufspace); 5550 db_printf("\thibufspace\t%ld\n", bd->bd_hibufspace); 5551 db_printf("\tlobufspace\t%ld\n", bd->bd_lobufspace); 5552 db_printf("\tbufspacethresh\t%ld\n", bd->bd_bufspacethresh); 5553 db_printf("\n"); 5554 db_printf("\tnumdirtybuffers\t%d\n", bd->bd_numdirtybuffers); 5555 db_printf("\tlodirtybuffers\t%d\n", bd->bd_lodirtybuffers); 5556 db_printf("\thidirtybuffers\t%d\n", bd->bd_hidirtybuffers); 5557 db_printf("\tdirtybufthresh\t%d\n", bd->bd_dirtybufthresh); 5558 db_printf("\n"); 5559 total = 0; 5560 TAILQ_FOREACH(bp, &bd->bd_cleanq->bq_queue, b_freelist) 5561 total += bp->b_bufsize; 5562 db_printf("\tcleanq count\t%d (%ld)\n", 5563 bd->bd_cleanq->bq_len, total); 5564 total = 0; 5565 TAILQ_FOREACH(bp, &bd->bd_dirtyq.bq_queue, b_freelist) 5566 total += bp->b_bufsize; 5567 db_printf("\tdirtyq count\t%d (%ld)\n", 5568 bd->bd_dirtyq.bq_len, total); 5569 db_printf("\twakeup\t\t%d\n", bd->bd_wanted); 5570 db_printf("\tlim\t\t%d\n", bd->bd_lim); 5571 db_printf("\tCPU "); 5572 for (j = 0; j <= mp_maxid; j++) 5573 db_printf("%d, ", bd->bd_subq[j].bq_len); 5574 db_printf("\n"); 5575 cnt = 0; 5576 total = 0; 5577 for (j = 0; j < nbuf; j++) { 5578 bp = nbufp(j); 5579 if (bp->b_domain == i && BUF_ISLOCKED(bp)) { 5580 cnt++; 5581 total += bp->b_bufsize; 5582 } 5583 } 5584 db_printf("\tLocked buffers: %d space %ld\n", cnt, total); 5585 cnt = 0; 5586 total = 0; 5587 for (j = 0; j < nbuf; j++) { 5588 bp = nbufp(j); 5589 if (bp->b_domain == i) { 5590 cnt++; 5591 total += bp->b_bufsize; 5592 } 5593 } 5594 db_printf("\tTotal buffers: %d space %ld\n", cnt, total); 5595 } 5596 } 5597 5598 DB_SHOW_COMMAND_FLAGS(lockedbufs, lockedbufs, DB_CMD_MEMSAFE) 5599 { 5600 struct buf *bp; 5601 int i; 5602 5603 for (i = 0; i < nbuf; i++) { 5604 bp = nbufp(i); 5605 if (BUF_ISLOCKED(bp)) { 5606 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5607 db_printf("\n"); 5608 if (db_pager_quit) 5609 break; 5610 } 5611 } 5612 } 5613 5614 DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs) 5615 { 5616 struct vnode *vp; 5617 struct buf *bp; 5618 5619 if (!have_addr) { 5620 db_printf("usage: show vnodebufs <addr>\n"); 5621 return; 5622 } 5623 vp = (struct vnode *)addr; 5624 db_printf("Clean buffers:\n"); 5625 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) { 5626 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5627 db_printf("\n"); 5628 } 5629 db_printf("Dirty buffers:\n"); 5630 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) { 5631 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5632 db_printf("\n"); 5633 } 5634 } 5635 5636 DB_COMMAND_FLAGS(countfreebufs, db_coundfreebufs, DB_CMD_MEMSAFE) 5637 { 5638 struct buf *bp; 5639 int i, used = 0, nfree = 0; 5640 5641 if (have_addr) { 5642 db_printf("usage: countfreebufs\n"); 5643 return; 5644 } 5645 5646 for (i = 0; i < nbuf; i++) { 5647 bp = nbufp(i); 5648 if (bp->b_qindex == QUEUE_EMPTY) 5649 nfree++; 5650 else 5651 used++; 5652 } 5653 5654 db_printf("Counted %d free, %d used (%d tot)\n", nfree, used, 5655 nfree + used); 5656 db_printf("numfreebuffers is %d\n", numfreebuffers); 5657 } 5658 #endif /* DDB */ 5659