1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2004 Poul-Henning Kamp 5 * Copyright (c) 1994,1997 John S. Dyson 6 * Copyright (c) 2013 The FreeBSD Foundation 7 * All rights reserved. 8 * 9 * Portions of this software were developed by Konstantin Belousov 10 * under sponsorship from the FreeBSD Foundation. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * this file contains a new buffer I/O scheme implementing a coherent 36 * VM object and buffer cache scheme. Pains have been taken to make 37 * sure that the performance degradation associated with schemes such 38 * as this is not realized. 39 * 40 * Author: John S. Dyson 41 * Significant help during the development and debugging phases 42 * had been provided by David Greenman, also of the FreeBSD core team. 43 * 44 * see man buf(9) for more info. 45 */ 46 47 #include <sys/cdefs.h> 48 __FBSDID("$FreeBSD$"); 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/asan.h> 53 #include <sys/bio.h> 54 #include <sys/bitset.h> 55 #include <sys/conf.h> 56 #include <sys/counter.h> 57 #include <sys/buf.h> 58 #include <sys/devicestat.h> 59 #include <sys/eventhandler.h> 60 #include <sys/fail.h> 61 #include <sys/ktr.h> 62 #include <sys/limits.h> 63 #include <sys/lock.h> 64 #include <sys/malloc.h> 65 #include <sys/mount.h> 66 #include <sys/mutex.h> 67 #include <sys/kernel.h> 68 #include <sys/kthread.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/smp.h> 75 #include <sys/sysctl.h> 76 #include <sys/syscallsubr.h> 77 #include <sys/vmem.h> 78 #include <sys/vmmeter.h> 79 #include <sys/vnode.h> 80 #include <sys/watchdog.h> 81 #include <geom/geom.h> 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <vm/vm_kern.h> 85 #include <vm/vm_object.h> 86 #include <vm/vm_page.h> 87 #include <vm/vm_pageout.h> 88 #include <vm/vm_pager.h> 89 #include <vm/vm_extern.h> 90 #include <vm/vm_map.h> 91 #include <vm/swap_pager.h> 92 93 static MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer"); 94 95 struct bio_ops bioops; /* I/O operation notification */ 96 97 struct buf_ops buf_ops_bio = { 98 .bop_name = "buf_ops_bio", 99 .bop_write = bufwrite, 100 .bop_strategy = bufstrategy, 101 .bop_sync = bufsync, 102 .bop_bdflush = bufbdflush, 103 }; 104 105 struct bufqueue { 106 struct mtx_padalign bq_lock; 107 TAILQ_HEAD(, buf) bq_queue; 108 uint8_t bq_index; 109 uint16_t bq_subqueue; 110 int bq_len; 111 } __aligned(CACHE_LINE_SIZE); 112 113 #define BQ_LOCKPTR(bq) (&(bq)->bq_lock) 114 #define BQ_LOCK(bq) mtx_lock(BQ_LOCKPTR((bq))) 115 #define BQ_UNLOCK(bq) mtx_unlock(BQ_LOCKPTR((bq))) 116 #define BQ_ASSERT_LOCKED(bq) mtx_assert(BQ_LOCKPTR((bq)), MA_OWNED) 117 118 struct bufdomain { 119 struct bufqueue bd_subq[MAXCPU + 1]; /* Per-cpu sub queues + global */ 120 struct bufqueue bd_dirtyq; 121 struct bufqueue *bd_cleanq; 122 struct mtx_padalign bd_run_lock; 123 /* Constants */ 124 long bd_maxbufspace; 125 long bd_hibufspace; 126 long bd_lobufspace; 127 long bd_bufspacethresh; 128 int bd_hifreebuffers; 129 int bd_lofreebuffers; 130 int bd_hidirtybuffers; 131 int bd_lodirtybuffers; 132 int bd_dirtybufthresh; 133 int bd_lim; 134 /* atomics */ 135 int bd_wanted; 136 int __aligned(CACHE_LINE_SIZE) bd_numdirtybuffers; 137 int __aligned(CACHE_LINE_SIZE) bd_running; 138 long __aligned(CACHE_LINE_SIZE) bd_bufspace; 139 int __aligned(CACHE_LINE_SIZE) bd_freebuffers; 140 } __aligned(CACHE_LINE_SIZE); 141 142 #define BD_LOCKPTR(bd) (&(bd)->bd_cleanq->bq_lock) 143 #define BD_LOCK(bd) mtx_lock(BD_LOCKPTR((bd))) 144 #define BD_UNLOCK(bd) mtx_unlock(BD_LOCKPTR((bd))) 145 #define BD_ASSERT_LOCKED(bd) mtx_assert(BD_LOCKPTR((bd)), MA_OWNED) 146 #define BD_RUN_LOCKPTR(bd) (&(bd)->bd_run_lock) 147 #define BD_RUN_LOCK(bd) mtx_lock(BD_RUN_LOCKPTR((bd))) 148 #define BD_RUN_UNLOCK(bd) mtx_unlock(BD_RUN_LOCKPTR((bd))) 149 #define BD_DOMAIN(bd) (bd - bdomain) 150 151 static char *buf; /* buffer header pool */ 152 static struct buf * 153 nbufp(unsigned i) 154 { 155 return ((struct buf *)(buf + (sizeof(struct buf) + 156 sizeof(vm_page_t) * atop(maxbcachebuf)) * i)); 157 } 158 159 caddr_t __read_mostly unmapped_buf; 160 161 /* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.c */ 162 struct proc *bufdaemonproc; 163 164 static void vm_hold_free_pages(struct buf *bp, int newbsize); 165 static void vm_hold_load_pages(struct buf *bp, vm_offset_t from, 166 vm_offset_t to); 167 static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m); 168 static void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, 169 vm_page_t m); 170 static void vfs_clean_pages_dirty_buf(struct buf *bp); 171 static void vfs_setdirty_range(struct buf *bp); 172 static void vfs_vmio_invalidate(struct buf *bp); 173 static void vfs_vmio_truncate(struct buf *bp, int npages); 174 static void vfs_vmio_extend(struct buf *bp, int npages, int size); 175 static int vfs_bio_clcheck(struct vnode *vp, int size, 176 daddr_t lblkno, daddr_t blkno); 177 static void breada(struct vnode *, daddr_t *, int *, int, struct ucred *, int, 178 void (*)(struct buf *)); 179 static int buf_flush(struct vnode *vp, struct bufdomain *, int); 180 static int flushbufqueues(struct vnode *, struct bufdomain *, int, int); 181 static void buf_daemon(void); 182 static __inline void bd_wakeup(void); 183 static int sysctl_runningspace(SYSCTL_HANDLER_ARGS); 184 static void bufkva_reclaim(vmem_t *, int); 185 static void bufkva_free(struct buf *); 186 static int buf_import(void *, void **, int, int, int); 187 static void buf_release(void *, void **, int); 188 static void maxbcachebuf_adjust(void); 189 static inline struct bufdomain *bufdomain(struct buf *); 190 static void bq_remove(struct bufqueue *bq, struct buf *bp); 191 static void bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock); 192 static int buf_recycle(struct bufdomain *, bool kva); 193 static void bq_init(struct bufqueue *bq, int qindex, int cpu, 194 const char *lockname); 195 static void bd_init(struct bufdomain *bd); 196 static int bd_flushall(struct bufdomain *bd); 197 static int sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS); 198 static int sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS); 199 200 static int sysctl_bufspace(SYSCTL_HANDLER_ARGS); 201 int vmiodirenable = TRUE; 202 SYSCTL_INT(_vfs, OID_AUTO, vmiodirenable, CTLFLAG_RW, &vmiodirenable, 0, 203 "Use the VM system for directory writes"); 204 long runningbufspace; 205 SYSCTL_LONG(_vfs, OID_AUTO, runningbufspace, CTLFLAG_RD, &runningbufspace, 0, 206 "Amount of presently outstanding async buffer io"); 207 SYSCTL_PROC(_vfs, OID_AUTO, bufspace, CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RD, 208 NULL, 0, sysctl_bufspace, "L", "Physical memory used for buffers"); 209 static counter_u64_t bufkvaspace; 210 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufkvaspace, CTLFLAG_RD, &bufkvaspace, 211 "Kernel virtual memory used for buffers"); 212 static long maxbufspace; 213 SYSCTL_PROC(_vfs, OID_AUTO, maxbufspace, 214 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &maxbufspace, 215 __offsetof(struct bufdomain, bd_maxbufspace), sysctl_bufdomain_long, "L", 216 "Maximum allowed value of bufspace (including metadata)"); 217 static long bufmallocspace; 218 SYSCTL_LONG(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0, 219 "Amount of malloced memory for buffers"); 220 static long maxbufmallocspace; 221 SYSCTL_LONG(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace, 222 0, "Maximum amount of malloced memory for buffers"); 223 static long lobufspace; 224 SYSCTL_PROC(_vfs, OID_AUTO, lobufspace, 225 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &lobufspace, 226 __offsetof(struct bufdomain, bd_lobufspace), sysctl_bufdomain_long, "L", 227 "Minimum amount of buffers we want to have"); 228 long hibufspace; 229 SYSCTL_PROC(_vfs, OID_AUTO, hibufspace, 230 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &hibufspace, 231 __offsetof(struct bufdomain, bd_hibufspace), sysctl_bufdomain_long, "L", 232 "Maximum allowed value of bufspace (excluding metadata)"); 233 long bufspacethresh; 234 SYSCTL_PROC(_vfs, OID_AUTO, bufspacethresh, 235 CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RW, &bufspacethresh, 236 __offsetof(struct bufdomain, bd_bufspacethresh), sysctl_bufdomain_long, "L", 237 "Bufspace consumed before waking the daemon to free some"); 238 static counter_u64_t buffreekvacnt; 239 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, buffreekvacnt, CTLFLAG_RW, &buffreekvacnt, 240 "Number of times we have freed the KVA space from some buffer"); 241 static counter_u64_t bufdefragcnt; 242 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, bufdefragcnt, CTLFLAG_RW, &bufdefragcnt, 243 "Number of times we have had to repeat buffer allocation to defragment"); 244 static long lorunningspace; 245 SYSCTL_PROC(_vfs, OID_AUTO, lorunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 246 CTLFLAG_RW, &lorunningspace, 0, sysctl_runningspace, "L", 247 "Minimum preferred space used for in-progress I/O"); 248 static long hirunningspace; 249 SYSCTL_PROC(_vfs, OID_AUTO, hirunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE | 250 CTLFLAG_RW, &hirunningspace, 0, sysctl_runningspace, "L", 251 "Maximum amount of space to use for in-progress I/O"); 252 int dirtybufferflushes; 253 SYSCTL_INT(_vfs, OID_AUTO, dirtybufferflushes, CTLFLAG_RW, &dirtybufferflushes, 254 0, "Number of bdwrite to bawrite conversions to limit dirty buffers"); 255 int bdwriteskip; 256 SYSCTL_INT(_vfs, OID_AUTO, bdwriteskip, CTLFLAG_RW, &bdwriteskip, 257 0, "Number of buffers supplied to bdwrite with snapshot deadlock risk"); 258 int altbufferflushes; 259 SYSCTL_INT(_vfs, OID_AUTO, altbufferflushes, CTLFLAG_RW | CTLFLAG_STATS, 260 &altbufferflushes, 0, "Number of fsync flushes to limit dirty buffers"); 261 static int recursiveflushes; 262 SYSCTL_INT(_vfs, OID_AUTO, recursiveflushes, CTLFLAG_RW | CTLFLAG_STATS, 263 &recursiveflushes, 0, "Number of flushes skipped due to being recursive"); 264 static int sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS); 265 SYSCTL_PROC(_vfs, OID_AUTO, numdirtybuffers, 266 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RD, NULL, 0, sysctl_numdirtybuffers, "I", 267 "Number of buffers that are dirty (has unwritten changes) at the moment"); 268 static int lodirtybuffers; 269 SYSCTL_PROC(_vfs, OID_AUTO, lodirtybuffers, 270 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lodirtybuffers, 271 __offsetof(struct bufdomain, bd_lodirtybuffers), sysctl_bufdomain_int, "I", 272 "How many buffers we want to have free before bufdaemon can sleep"); 273 static int hidirtybuffers; 274 SYSCTL_PROC(_vfs, OID_AUTO, hidirtybuffers, 275 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hidirtybuffers, 276 __offsetof(struct bufdomain, bd_hidirtybuffers), sysctl_bufdomain_int, "I", 277 "When the number of dirty buffers is considered severe"); 278 int dirtybufthresh; 279 SYSCTL_PROC(_vfs, OID_AUTO, dirtybufthresh, 280 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &dirtybufthresh, 281 __offsetof(struct bufdomain, bd_dirtybufthresh), sysctl_bufdomain_int, "I", 282 "Number of bdwrite to bawrite conversions to clear dirty buffers"); 283 static int numfreebuffers; 284 SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0, 285 "Number of free buffers"); 286 static int lofreebuffers; 287 SYSCTL_PROC(_vfs, OID_AUTO, lofreebuffers, 288 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &lofreebuffers, 289 __offsetof(struct bufdomain, bd_lofreebuffers), sysctl_bufdomain_int, "I", 290 "Target number of free buffers"); 291 static int hifreebuffers; 292 SYSCTL_PROC(_vfs, OID_AUTO, hifreebuffers, 293 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &hifreebuffers, 294 __offsetof(struct bufdomain, bd_hifreebuffers), sysctl_bufdomain_int, "I", 295 "Threshold for clean buffer recycling"); 296 static counter_u64_t getnewbufcalls; 297 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufcalls, CTLFLAG_RD, 298 &getnewbufcalls, "Number of calls to getnewbuf"); 299 static counter_u64_t getnewbufrestarts; 300 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, getnewbufrestarts, CTLFLAG_RD, 301 &getnewbufrestarts, 302 "Number of times getnewbuf has had to restart a buffer acquisition"); 303 static counter_u64_t mappingrestarts; 304 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, mappingrestarts, CTLFLAG_RD, 305 &mappingrestarts, 306 "Number of times getblk has had to restart a buffer mapping for " 307 "unmapped buffer"); 308 static counter_u64_t numbufallocfails; 309 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, numbufallocfails, CTLFLAG_RW, 310 &numbufallocfails, "Number of times buffer allocations failed"); 311 static int flushbufqtarget = 100; 312 SYSCTL_INT(_vfs, OID_AUTO, flushbufqtarget, CTLFLAG_RW, &flushbufqtarget, 0, 313 "Amount of work to do in flushbufqueues when helping bufdaemon"); 314 static counter_u64_t notbufdflushes; 315 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, notbufdflushes, CTLFLAG_RD, ¬bufdflushes, 316 "Number of dirty buffer flushes done by the bufdaemon helpers"); 317 static long barrierwrites; 318 SYSCTL_LONG(_vfs, OID_AUTO, barrierwrites, CTLFLAG_RW | CTLFLAG_STATS, 319 &barrierwrites, 0, "Number of barrier writes"); 320 SYSCTL_INT(_vfs, OID_AUTO, unmapped_buf_allowed, CTLFLAG_RD, 321 &unmapped_buf_allowed, 0, 322 "Permit the use of the unmapped i/o"); 323 int maxbcachebuf = MAXBCACHEBUF; 324 SYSCTL_INT(_vfs, OID_AUTO, maxbcachebuf, CTLFLAG_RDTUN, &maxbcachebuf, 0, 325 "Maximum size of a buffer cache block"); 326 327 /* 328 * This lock synchronizes access to bd_request. 329 */ 330 static struct mtx_padalign __exclusive_cache_line bdlock; 331 332 /* 333 * This lock protects the runningbufreq and synchronizes runningbufwakeup and 334 * waitrunningbufspace(). 335 */ 336 static struct mtx_padalign __exclusive_cache_line rbreqlock; 337 338 /* 339 * Lock that protects bdirtywait. 340 */ 341 static struct mtx_padalign __exclusive_cache_line bdirtylock; 342 343 /* 344 * Wakeup point for bufdaemon, as well as indicator of whether it is already 345 * active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it 346 * is idling. 347 */ 348 static int bd_request; 349 350 /* 351 * Request for the buf daemon to write more buffers than is indicated by 352 * lodirtybuf. This may be necessary to push out excess dependencies or 353 * defragment the address space where a simple count of the number of dirty 354 * buffers is insufficient to characterize the demand for flushing them. 355 */ 356 static int bd_speedupreq; 357 358 /* 359 * Synchronization (sleep/wakeup) variable for active buffer space requests. 360 * Set when wait starts, cleared prior to wakeup(). 361 * Used in runningbufwakeup() and waitrunningbufspace(). 362 */ 363 static int runningbufreq; 364 365 /* 366 * Synchronization for bwillwrite() waiters. 367 */ 368 static int bdirtywait; 369 370 /* 371 * Definitions for the buffer free lists. 372 */ 373 #define QUEUE_NONE 0 /* on no queue */ 374 #define QUEUE_EMPTY 1 /* empty buffer headers */ 375 #define QUEUE_DIRTY 2 /* B_DELWRI buffers */ 376 #define QUEUE_CLEAN 3 /* non-B_DELWRI buffers */ 377 #define QUEUE_SENTINEL 4 /* not an queue index, but mark for sentinel */ 378 379 /* Maximum number of buffer domains. */ 380 #define BUF_DOMAINS 8 381 382 struct bufdomainset bdlodirty; /* Domains > lodirty */ 383 struct bufdomainset bdhidirty; /* Domains > hidirty */ 384 385 /* Configured number of clean queues. */ 386 static int __read_mostly buf_domains; 387 388 BITSET_DEFINE(bufdomainset, BUF_DOMAINS); 389 struct bufdomain __exclusive_cache_line bdomain[BUF_DOMAINS]; 390 struct bufqueue __exclusive_cache_line bqempty; 391 392 /* 393 * per-cpu empty buffer cache. 394 */ 395 uma_zone_t buf_zone; 396 397 /* 398 * Single global constant for BUF_WMESG, to avoid getting multiple references. 399 * buf_wmesg is referred from macros. 400 */ 401 const char *buf_wmesg = BUF_WMESG; 402 403 static int 404 sysctl_runningspace(SYSCTL_HANDLER_ARGS) 405 { 406 long value; 407 int error; 408 409 value = *(long *)arg1; 410 error = sysctl_handle_long(oidp, &value, 0, req); 411 if (error != 0 || req->newptr == NULL) 412 return (error); 413 mtx_lock(&rbreqlock); 414 if (arg1 == &hirunningspace) { 415 if (value < lorunningspace) 416 error = EINVAL; 417 else 418 hirunningspace = value; 419 } else { 420 KASSERT(arg1 == &lorunningspace, 421 ("%s: unknown arg1", __func__)); 422 if (value > hirunningspace) 423 error = EINVAL; 424 else 425 lorunningspace = value; 426 } 427 mtx_unlock(&rbreqlock); 428 return (error); 429 } 430 431 static int 432 sysctl_bufdomain_int(SYSCTL_HANDLER_ARGS) 433 { 434 int error; 435 int value; 436 int i; 437 438 value = *(int *)arg1; 439 error = sysctl_handle_int(oidp, &value, 0, req); 440 if (error != 0 || req->newptr == NULL) 441 return (error); 442 *(int *)arg1 = value; 443 for (i = 0; i < buf_domains; i++) 444 *(int *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 445 value / buf_domains; 446 447 return (error); 448 } 449 450 static int 451 sysctl_bufdomain_long(SYSCTL_HANDLER_ARGS) 452 { 453 long value; 454 int error; 455 int i; 456 457 value = *(long *)arg1; 458 error = sysctl_handle_long(oidp, &value, 0, req); 459 if (error != 0 || req->newptr == NULL) 460 return (error); 461 *(long *)arg1 = value; 462 for (i = 0; i < buf_domains; i++) 463 *(long *)(uintptr_t)(((uintptr_t)&bdomain[i]) + arg2) = 464 value / buf_domains; 465 466 return (error); 467 } 468 469 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \ 470 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) 471 static int 472 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 473 { 474 long lvalue; 475 int ivalue; 476 int i; 477 478 lvalue = 0; 479 for (i = 0; i < buf_domains; i++) 480 lvalue += bdomain[i].bd_bufspace; 481 if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long)) 482 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 483 if (lvalue > INT_MAX) 484 /* On overflow, still write out a long to trigger ENOMEM. */ 485 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 486 ivalue = lvalue; 487 return (sysctl_handle_int(oidp, &ivalue, 0, req)); 488 } 489 #else 490 static int 491 sysctl_bufspace(SYSCTL_HANDLER_ARGS) 492 { 493 long lvalue; 494 int i; 495 496 lvalue = 0; 497 for (i = 0; i < buf_domains; i++) 498 lvalue += bdomain[i].bd_bufspace; 499 return (sysctl_handle_long(oidp, &lvalue, 0, req)); 500 } 501 #endif 502 503 static int 504 sysctl_numdirtybuffers(SYSCTL_HANDLER_ARGS) 505 { 506 int value; 507 int i; 508 509 value = 0; 510 for (i = 0; i < buf_domains; i++) 511 value += bdomain[i].bd_numdirtybuffers; 512 return (sysctl_handle_int(oidp, &value, 0, req)); 513 } 514 515 /* 516 * bdirtywakeup: 517 * 518 * Wakeup any bwillwrite() waiters. 519 */ 520 static void 521 bdirtywakeup(void) 522 { 523 mtx_lock(&bdirtylock); 524 if (bdirtywait) { 525 bdirtywait = 0; 526 wakeup(&bdirtywait); 527 } 528 mtx_unlock(&bdirtylock); 529 } 530 531 /* 532 * bd_clear: 533 * 534 * Clear a domain from the appropriate bitsets when dirtybuffers 535 * is decremented. 536 */ 537 static void 538 bd_clear(struct bufdomain *bd) 539 { 540 541 mtx_lock(&bdirtylock); 542 if (bd->bd_numdirtybuffers <= bd->bd_lodirtybuffers) 543 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 544 if (bd->bd_numdirtybuffers <= bd->bd_hidirtybuffers) 545 BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 546 mtx_unlock(&bdirtylock); 547 } 548 549 /* 550 * bd_set: 551 * 552 * Set a domain in the appropriate bitsets when dirtybuffers 553 * is incremented. 554 */ 555 static void 556 bd_set(struct bufdomain *bd) 557 { 558 559 mtx_lock(&bdirtylock); 560 if (bd->bd_numdirtybuffers > bd->bd_lodirtybuffers) 561 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty); 562 if (bd->bd_numdirtybuffers > bd->bd_hidirtybuffers) 563 BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty); 564 mtx_unlock(&bdirtylock); 565 } 566 567 /* 568 * bdirtysub: 569 * 570 * Decrement the numdirtybuffers count by one and wakeup any 571 * threads blocked in bwillwrite(). 572 */ 573 static void 574 bdirtysub(struct buf *bp) 575 { 576 struct bufdomain *bd; 577 int num; 578 579 bd = bufdomain(bp); 580 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, -1); 581 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 582 bdirtywakeup(); 583 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 584 bd_clear(bd); 585 } 586 587 /* 588 * bdirtyadd: 589 * 590 * Increment the numdirtybuffers count by one and wakeup the buf 591 * daemon if needed. 592 */ 593 static void 594 bdirtyadd(struct buf *bp) 595 { 596 struct bufdomain *bd; 597 int num; 598 599 /* 600 * Only do the wakeup once as we cross the boundary. The 601 * buf daemon will keep running until the condition clears. 602 */ 603 bd = bufdomain(bp); 604 num = atomic_fetchadd_int(&bd->bd_numdirtybuffers, 1); 605 if (num == (bd->bd_lodirtybuffers + bd->bd_hidirtybuffers) / 2) 606 bd_wakeup(); 607 if (num == bd->bd_lodirtybuffers || num == bd->bd_hidirtybuffers) 608 bd_set(bd); 609 } 610 611 /* 612 * bufspace_daemon_wakeup: 613 * 614 * Wakeup the daemons responsible for freeing clean bufs. 615 */ 616 static void 617 bufspace_daemon_wakeup(struct bufdomain *bd) 618 { 619 620 /* 621 * avoid the lock if the daemon is running. 622 */ 623 if (atomic_fetchadd_int(&bd->bd_running, 1) == 0) { 624 BD_RUN_LOCK(bd); 625 atomic_store_int(&bd->bd_running, 1); 626 wakeup(&bd->bd_running); 627 BD_RUN_UNLOCK(bd); 628 } 629 } 630 631 /* 632 * bufspace_daemon_wait: 633 * 634 * Sleep until the domain falls below a limit or one second passes. 635 */ 636 static void 637 bufspace_daemon_wait(struct bufdomain *bd) 638 { 639 /* 640 * Re-check our limits and sleep. bd_running must be 641 * cleared prior to checking the limits to avoid missed 642 * wakeups. The waker will adjust one of bufspace or 643 * freebuffers prior to checking bd_running. 644 */ 645 BD_RUN_LOCK(bd); 646 atomic_store_int(&bd->bd_running, 0); 647 if (bd->bd_bufspace < bd->bd_bufspacethresh && 648 bd->bd_freebuffers > bd->bd_lofreebuffers) { 649 msleep(&bd->bd_running, BD_RUN_LOCKPTR(bd), PRIBIO|PDROP, 650 "-", hz); 651 } else { 652 /* Avoid spurious wakeups while running. */ 653 atomic_store_int(&bd->bd_running, 1); 654 BD_RUN_UNLOCK(bd); 655 } 656 } 657 658 /* 659 * bufspace_adjust: 660 * 661 * Adjust the reported bufspace for a KVA managed buffer, possibly 662 * waking any waiters. 663 */ 664 static void 665 bufspace_adjust(struct buf *bp, int bufsize) 666 { 667 struct bufdomain *bd; 668 long space; 669 int diff; 670 671 KASSERT((bp->b_flags & B_MALLOC) == 0, 672 ("bufspace_adjust: malloc buf %p", bp)); 673 bd = bufdomain(bp); 674 diff = bufsize - bp->b_bufsize; 675 if (diff < 0) { 676 atomic_subtract_long(&bd->bd_bufspace, -diff); 677 } else if (diff > 0) { 678 space = atomic_fetchadd_long(&bd->bd_bufspace, diff); 679 /* Wake up the daemon on the transition. */ 680 if (space < bd->bd_bufspacethresh && 681 space + diff >= bd->bd_bufspacethresh) 682 bufspace_daemon_wakeup(bd); 683 } 684 bp->b_bufsize = bufsize; 685 } 686 687 /* 688 * bufspace_reserve: 689 * 690 * Reserve bufspace before calling allocbuf(). metadata has a 691 * different space limit than data. 692 */ 693 static int 694 bufspace_reserve(struct bufdomain *bd, int size, bool metadata) 695 { 696 long limit, new; 697 long space; 698 699 if (metadata) 700 limit = bd->bd_maxbufspace; 701 else 702 limit = bd->bd_hibufspace; 703 space = atomic_fetchadd_long(&bd->bd_bufspace, size); 704 new = space + size; 705 if (new > limit) { 706 atomic_subtract_long(&bd->bd_bufspace, size); 707 return (ENOSPC); 708 } 709 710 /* Wake up the daemon on the transition. */ 711 if (space < bd->bd_bufspacethresh && new >= bd->bd_bufspacethresh) 712 bufspace_daemon_wakeup(bd); 713 714 return (0); 715 } 716 717 /* 718 * bufspace_release: 719 * 720 * Release reserved bufspace after bufspace_adjust() has consumed it. 721 */ 722 static void 723 bufspace_release(struct bufdomain *bd, int size) 724 { 725 726 atomic_subtract_long(&bd->bd_bufspace, size); 727 } 728 729 /* 730 * bufspace_wait: 731 * 732 * Wait for bufspace, acting as the buf daemon if a locked vnode is 733 * supplied. bd_wanted must be set prior to polling for space. The 734 * operation must be re-tried on return. 735 */ 736 static void 737 bufspace_wait(struct bufdomain *bd, struct vnode *vp, int gbflags, 738 int slpflag, int slptimeo) 739 { 740 struct thread *td; 741 int error, fl, norunbuf; 742 743 if ((gbflags & GB_NOWAIT_BD) != 0) 744 return; 745 746 td = curthread; 747 BD_LOCK(bd); 748 while (bd->bd_wanted) { 749 if (vp != NULL && vp->v_type != VCHR && 750 (td->td_pflags & TDP_BUFNEED) == 0) { 751 BD_UNLOCK(bd); 752 /* 753 * getblk() is called with a vnode locked, and 754 * some majority of the dirty buffers may as 755 * well belong to the vnode. Flushing the 756 * buffers there would make a progress that 757 * cannot be achieved by the buf_daemon, that 758 * cannot lock the vnode. 759 */ 760 norunbuf = ~(TDP_BUFNEED | TDP_NORUNNINGBUF) | 761 (td->td_pflags & TDP_NORUNNINGBUF); 762 763 /* 764 * Play bufdaemon. The getnewbuf() function 765 * may be called while the thread owns lock 766 * for another dirty buffer for the same 767 * vnode, which makes it impossible to use 768 * VOP_FSYNC() there, due to the buffer lock 769 * recursion. 770 */ 771 td->td_pflags |= TDP_BUFNEED | TDP_NORUNNINGBUF; 772 fl = buf_flush(vp, bd, flushbufqtarget); 773 td->td_pflags &= norunbuf; 774 BD_LOCK(bd); 775 if (fl != 0) 776 continue; 777 if (bd->bd_wanted == 0) 778 break; 779 } 780 error = msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 781 (PRIBIO + 4) | slpflag, "newbuf", slptimeo); 782 if (error != 0) 783 break; 784 } 785 BD_UNLOCK(bd); 786 } 787 788 /* 789 * bufspace_daemon: 790 * 791 * buffer space management daemon. Tries to maintain some marginal 792 * amount of free buffer space so that requesting processes neither 793 * block nor work to reclaim buffers. 794 */ 795 static void 796 bufspace_daemon(void *arg) 797 { 798 struct bufdomain *bd; 799 800 EVENTHANDLER_REGISTER(shutdown_pre_sync, kthread_shutdown, curthread, 801 SHUTDOWN_PRI_LAST + 100); 802 803 bd = arg; 804 for (;;) { 805 kthread_suspend_check(); 806 807 /* 808 * Free buffers from the clean queue until we meet our 809 * targets. 810 * 811 * Theory of operation: The buffer cache is most efficient 812 * when some free buffer headers and space are always 813 * available to getnewbuf(). This daemon attempts to prevent 814 * the excessive blocking and synchronization associated 815 * with shortfall. It goes through three phases according 816 * demand: 817 * 818 * 1) The daemon wakes up voluntarily once per-second 819 * during idle periods when the counters are below 820 * the wakeup thresholds (bufspacethresh, lofreebuffers). 821 * 822 * 2) The daemon wakes up as we cross the thresholds 823 * ahead of any potential blocking. This may bounce 824 * slightly according to the rate of consumption and 825 * release. 826 * 827 * 3) The daemon and consumers are starved for working 828 * clean buffers. This is the 'bufspace' sleep below 829 * which will inefficiently trade bufs with bqrelse 830 * until we return to condition 2. 831 */ 832 while (bd->bd_bufspace > bd->bd_lobufspace || 833 bd->bd_freebuffers < bd->bd_hifreebuffers) { 834 if (buf_recycle(bd, false) != 0) { 835 if (bd_flushall(bd)) 836 continue; 837 /* 838 * Speedup dirty if we've run out of clean 839 * buffers. This is possible in particular 840 * because softdep may held many bufs locked 841 * pending writes to other bufs which are 842 * marked for delayed write, exhausting 843 * clean space until they are written. 844 */ 845 bd_speedup(); 846 BD_LOCK(bd); 847 if (bd->bd_wanted) { 848 msleep(&bd->bd_wanted, BD_LOCKPTR(bd), 849 PRIBIO|PDROP, "bufspace", hz/10); 850 } else 851 BD_UNLOCK(bd); 852 } 853 maybe_yield(); 854 } 855 bufspace_daemon_wait(bd); 856 } 857 } 858 859 /* 860 * bufmallocadjust: 861 * 862 * Adjust the reported bufspace for a malloc managed buffer, possibly 863 * waking any waiters. 864 */ 865 static void 866 bufmallocadjust(struct buf *bp, int bufsize) 867 { 868 int diff; 869 870 KASSERT((bp->b_flags & B_MALLOC) != 0, 871 ("bufmallocadjust: non-malloc buf %p", bp)); 872 diff = bufsize - bp->b_bufsize; 873 if (diff < 0) 874 atomic_subtract_long(&bufmallocspace, -diff); 875 else 876 atomic_add_long(&bufmallocspace, diff); 877 bp->b_bufsize = bufsize; 878 } 879 880 /* 881 * runningwakeup: 882 * 883 * Wake up processes that are waiting on asynchronous writes to fall 884 * below lorunningspace. 885 */ 886 static void 887 runningwakeup(void) 888 { 889 890 mtx_lock(&rbreqlock); 891 if (runningbufreq) { 892 runningbufreq = 0; 893 wakeup(&runningbufreq); 894 } 895 mtx_unlock(&rbreqlock); 896 } 897 898 /* 899 * runningbufwakeup: 900 * 901 * Decrement the outstanding write count according. 902 */ 903 void 904 runningbufwakeup(struct buf *bp) 905 { 906 long space, bspace; 907 908 bspace = bp->b_runningbufspace; 909 if (bspace == 0) 910 return; 911 space = atomic_fetchadd_long(&runningbufspace, -bspace); 912 KASSERT(space >= bspace, ("runningbufspace underflow %ld %ld", 913 space, bspace)); 914 bp->b_runningbufspace = 0; 915 /* 916 * Only acquire the lock and wakeup on the transition from exceeding 917 * the threshold to falling below it. 918 */ 919 if (space < lorunningspace) 920 return; 921 if (space - bspace > lorunningspace) 922 return; 923 runningwakeup(); 924 } 925 926 /* 927 * waitrunningbufspace() 928 * 929 * runningbufspace is a measure of the amount of I/O currently 930 * running. This routine is used in async-write situations to 931 * prevent creating huge backups of pending writes to a device. 932 * Only asynchronous writes are governed by this function. 933 * 934 * This does NOT turn an async write into a sync write. It waits 935 * for earlier writes to complete and generally returns before the 936 * caller's write has reached the device. 937 */ 938 void 939 waitrunningbufspace(void) 940 { 941 942 mtx_lock(&rbreqlock); 943 while (runningbufspace > hirunningspace) { 944 runningbufreq = 1; 945 msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0); 946 } 947 mtx_unlock(&rbreqlock); 948 } 949 950 /* 951 * vfs_buf_test_cache: 952 * 953 * Called when a buffer is extended. This function clears the B_CACHE 954 * bit if the newly extended portion of the buffer does not contain 955 * valid data. 956 */ 957 static __inline void 958 vfs_buf_test_cache(struct buf *bp, vm_ooffset_t foff, vm_offset_t off, 959 vm_offset_t size, vm_page_t m) 960 { 961 962 /* 963 * This function and its results are protected by higher level 964 * synchronization requiring vnode and buf locks to page in and 965 * validate pages. 966 */ 967 if (bp->b_flags & B_CACHE) { 968 int base = (foff + off) & PAGE_MASK; 969 if (vm_page_is_valid(m, base, size) == 0) 970 bp->b_flags &= ~B_CACHE; 971 } 972 } 973 974 /* Wake up the buffer daemon if necessary */ 975 static void 976 bd_wakeup(void) 977 { 978 979 mtx_lock(&bdlock); 980 if (bd_request == 0) { 981 bd_request = 1; 982 wakeup(&bd_request); 983 } 984 mtx_unlock(&bdlock); 985 } 986 987 /* 988 * Adjust the maxbcachbuf tunable. 989 */ 990 static void 991 maxbcachebuf_adjust(void) 992 { 993 int i; 994 995 /* 996 * maxbcachebuf must be a power of 2 >= MAXBSIZE. 997 */ 998 i = 2; 999 while (i * 2 <= maxbcachebuf) 1000 i *= 2; 1001 maxbcachebuf = i; 1002 if (maxbcachebuf < MAXBSIZE) 1003 maxbcachebuf = MAXBSIZE; 1004 if (maxbcachebuf > maxphys) 1005 maxbcachebuf = maxphys; 1006 if (bootverbose != 0 && maxbcachebuf != MAXBCACHEBUF) 1007 printf("maxbcachebuf=%d\n", maxbcachebuf); 1008 } 1009 1010 /* 1011 * bd_speedup - speedup the buffer cache flushing code 1012 */ 1013 void 1014 bd_speedup(void) 1015 { 1016 int needwake; 1017 1018 mtx_lock(&bdlock); 1019 needwake = 0; 1020 if (bd_speedupreq == 0 || bd_request == 0) 1021 needwake = 1; 1022 bd_speedupreq = 1; 1023 bd_request = 1; 1024 if (needwake) 1025 wakeup(&bd_request); 1026 mtx_unlock(&bdlock); 1027 } 1028 1029 #ifdef __i386__ 1030 #define TRANSIENT_DENOM 5 1031 #else 1032 #define TRANSIENT_DENOM 10 1033 #endif 1034 1035 /* 1036 * Calculating buffer cache scaling values and reserve space for buffer 1037 * headers. This is called during low level kernel initialization and 1038 * may be called more then once. We CANNOT write to the memory area 1039 * being reserved at this time. 1040 */ 1041 caddr_t 1042 kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est) 1043 { 1044 int tuned_nbuf; 1045 long maxbuf, maxbuf_sz, buf_sz, biotmap_sz; 1046 1047 /* 1048 * With KASAN or KMSAN enabled, the kernel map is shadowed. Account for 1049 * this when sizing maps based on the amount of physical memory 1050 * available. 1051 */ 1052 #if defined(KASAN) 1053 physmem_est = (physmem_est * KASAN_SHADOW_SCALE) / 1054 (KASAN_SHADOW_SCALE + 1); 1055 #elif defined(KMSAN) 1056 physmem_est /= 3; 1057 1058 /* 1059 * KMSAN cannot reliably determine whether buffer data is initialized 1060 * unless it is updated through a KVA mapping. 1061 */ 1062 unmapped_buf_allowed = 0; 1063 #endif 1064 1065 /* 1066 * physmem_est is in pages. Convert it to kilobytes (assumes 1067 * PAGE_SIZE is >= 1K) 1068 */ 1069 physmem_est = physmem_est * (PAGE_SIZE / 1024); 1070 1071 maxbcachebuf_adjust(); 1072 /* 1073 * The nominal buffer size (and minimum KVA allocation) is BKVASIZE. 1074 * For the first 64MB of ram nominally allocate sufficient buffers to 1075 * cover 1/4 of our ram. Beyond the first 64MB allocate additional 1076 * buffers to cover 1/10 of our ram over 64MB. When auto-sizing 1077 * the buffer cache we limit the eventual kva reservation to 1078 * maxbcache bytes. 1079 * 1080 * factor represents the 1/4 x ram conversion. 1081 */ 1082 if (nbuf == 0) { 1083 int factor = 4 * BKVASIZE / 1024; 1084 1085 nbuf = 50; 1086 if (physmem_est > 4096) 1087 nbuf += min((physmem_est - 4096) / factor, 1088 65536 / factor); 1089 if (physmem_est > 65536) 1090 nbuf += min((physmem_est - 65536) * 2 / (factor * 5), 1091 32 * 1024 * 1024 / (factor * 5)); 1092 1093 if (maxbcache && nbuf > maxbcache / BKVASIZE) 1094 nbuf = maxbcache / BKVASIZE; 1095 tuned_nbuf = 1; 1096 } else 1097 tuned_nbuf = 0; 1098 1099 /* XXX Avoid unsigned long overflows later on with maxbufspace. */ 1100 maxbuf = (LONG_MAX / 3) / BKVASIZE; 1101 if (nbuf > maxbuf) { 1102 if (!tuned_nbuf) 1103 printf("Warning: nbufs lowered from %d to %ld\n", nbuf, 1104 maxbuf); 1105 nbuf = maxbuf; 1106 } 1107 1108 /* 1109 * Ideal allocation size for the transient bio submap is 10% 1110 * of the maximal space buffer map. This roughly corresponds 1111 * to the amount of the buffer mapped for typical UFS load. 1112 * 1113 * Clip the buffer map to reserve space for the transient 1114 * BIOs, if its extent is bigger than 90% (80% on i386) of the 1115 * maximum buffer map extent on the platform. 1116 * 1117 * The fall-back to the maxbuf in case of maxbcache unset, 1118 * allows to not trim the buffer KVA for the architectures 1119 * with ample KVA space. 1120 */ 1121 if (bio_transient_maxcnt == 0 && unmapped_buf_allowed) { 1122 maxbuf_sz = maxbcache != 0 ? maxbcache : maxbuf * BKVASIZE; 1123 buf_sz = (long)nbuf * BKVASIZE; 1124 if (buf_sz < maxbuf_sz / TRANSIENT_DENOM * 1125 (TRANSIENT_DENOM - 1)) { 1126 /* 1127 * There is more KVA than memory. Do not 1128 * adjust buffer map size, and assign the rest 1129 * of maxbuf to transient map. 1130 */ 1131 biotmap_sz = maxbuf_sz - buf_sz; 1132 } else { 1133 /* 1134 * Buffer map spans all KVA we could afford on 1135 * this platform. Give 10% (20% on i386) of 1136 * the buffer map to the transient bio map. 1137 */ 1138 biotmap_sz = buf_sz / TRANSIENT_DENOM; 1139 buf_sz -= biotmap_sz; 1140 } 1141 if (biotmap_sz / INT_MAX > maxphys) 1142 bio_transient_maxcnt = INT_MAX; 1143 else 1144 bio_transient_maxcnt = biotmap_sz / maxphys; 1145 /* 1146 * Artificially limit to 1024 simultaneous in-flight I/Os 1147 * using the transient mapping. 1148 */ 1149 if (bio_transient_maxcnt > 1024) 1150 bio_transient_maxcnt = 1024; 1151 if (tuned_nbuf) 1152 nbuf = buf_sz / BKVASIZE; 1153 } 1154 1155 if (nswbuf == 0) { 1156 nswbuf = min(nbuf / 4, 256); 1157 if (nswbuf < NSWBUF_MIN) 1158 nswbuf = NSWBUF_MIN; 1159 } 1160 1161 /* 1162 * Reserve space for the buffer cache buffers 1163 */ 1164 buf = (char *)v; 1165 v = (caddr_t)buf + (sizeof(struct buf) + sizeof(vm_page_t) * 1166 atop(maxbcachebuf)) * nbuf; 1167 1168 return (v); 1169 } 1170 1171 /* Initialize the buffer subsystem. Called before use of any buffers. */ 1172 void 1173 bufinit(void) 1174 { 1175 struct buf *bp; 1176 int i; 1177 1178 KASSERT(maxbcachebuf >= MAXBSIZE, 1179 ("maxbcachebuf (%d) must be >= MAXBSIZE (%d)\n", maxbcachebuf, 1180 MAXBSIZE)); 1181 bq_init(&bqempty, QUEUE_EMPTY, -1, "bufq empty lock"); 1182 mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF); 1183 mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF); 1184 mtx_init(&bdirtylock, "dirty buf lock", NULL, MTX_DEF); 1185 1186 unmapped_buf = (caddr_t)kva_alloc(maxphys); 1187 1188 /* finally, initialize each buffer header and stick on empty q */ 1189 for (i = 0; i < nbuf; i++) { 1190 bp = nbufp(i); 1191 bzero(bp, sizeof(*bp) + sizeof(vm_page_t) * atop(maxbcachebuf)); 1192 bp->b_flags = B_INVAL; 1193 bp->b_rcred = NOCRED; 1194 bp->b_wcred = NOCRED; 1195 bp->b_qindex = QUEUE_NONE; 1196 bp->b_domain = -1; 1197 bp->b_subqueue = mp_maxid + 1; 1198 bp->b_xflags = 0; 1199 bp->b_data = bp->b_kvabase = unmapped_buf; 1200 LIST_INIT(&bp->b_dep); 1201 BUF_LOCKINIT(bp); 1202 bq_insert(&bqempty, bp, false); 1203 } 1204 1205 /* 1206 * maxbufspace is the absolute maximum amount of buffer space we are 1207 * allowed to reserve in KVM and in real terms. The absolute maximum 1208 * is nominally used by metadata. hibufspace is the nominal maximum 1209 * used by most other requests. The differential is required to 1210 * ensure that metadata deadlocks don't occur. 1211 * 1212 * maxbufspace is based on BKVASIZE. Allocating buffers larger then 1213 * this may result in KVM fragmentation which is not handled optimally 1214 * by the system. XXX This is less true with vmem. We could use 1215 * PAGE_SIZE. 1216 */ 1217 maxbufspace = (long)nbuf * BKVASIZE; 1218 hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - maxbcachebuf * 10); 1219 lobufspace = (hibufspace / 20) * 19; /* 95% */ 1220 bufspacethresh = lobufspace + (hibufspace - lobufspace) / 2; 1221 1222 /* 1223 * Note: The 16 MiB upper limit for hirunningspace was chosen 1224 * arbitrarily and may need further tuning. It corresponds to 1225 * 128 outstanding write IO requests (if IO size is 128 KiB), 1226 * which fits with many RAID controllers' tagged queuing limits. 1227 * The lower 1 MiB limit is the historical upper limit for 1228 * hirunningspace. 1229 */ 1230 hirunningspace = lmax(lmin(roundup(hibufspace / 64, maxbcachebuf), 1231 16 * 1024 * 1024), 1024 * 1024); 1232 lorunningspace = roundup((hirunningspace * 2) / 3, maxbcachebuf); 1233 1234 /* 1235 * Limit the amount of malloc memory since it is wired permanently into 1236 * the kernel space. Even though this is accounted for in the buffer 1237 * allocation, we don't want the malloced region to grow uncontrolled. 1238 * The malloc scheme improves memory utilization significantly on 1239 * average (small) directories. 1240 */ 1241 maxbufmallocspace = hibufspace / 20; 1242 1243 /* 1244 * Reduce the chance of a deadlock occurring by limiting the number 1245 * of delayed-write dirty buffers we allow to stack up. 1246 */ 1247 hidirtybuffers = nbuf / 4 + 20; 1248 dirtybufthresh = hidirtybuffers * 9 / 10; 1249 /* 1250 * To support extreme low-memory systems, make sure hidirtybuffers 1251 * cannot eat up all available buffer space. This occurs when our 1252 * minimum cannot be met. We try to size hidirtybuffers to 3/4 our 1253 * buffer space assuming BKVASIZE'd buffers. 1254 */ 1255 while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) { 1256 hidirtybuffers >>= 1; 1257 } 1258 lodirtybuffers = hidirtybuffers / 2; 1259 1260 /* 1261 * lofreebuffers should be sufficient to avoid stalling waiting on 1262 * buf headers under heavy utilization. The bufs in per-cpu caches 1263 * are counted as free but will be unavailable to threads executing 1264 * on other cpus. 1265 * 1266 * hifreebuffers is the free target for the bufspace daemon. This 1267 * should be set appropriately to limit work per-iteration. 1268 */ 1269 lofreebuffers = MIN((nbuf / 25) + (20 * mp_ncpus), 128 * mp_ncpus); 1270 hifreebuffers = (3 * lofreebuffers) / 2; 1271 numfreebuffers = nbuf; 1272 1273 /* Setup the kva and free list allocators. */ 1274 vmem_set_reclaim(buffer_arena, bufkva_reclaim); 1275 buf_zone = uma_zcache_create("buf free cache", 1276 sizeof(struct buf) + sizeof(vm_page_t) * atop(maxbcachebuf), 1277 NULL, NULL, NULL, NULL, buf_import, buf_release, NULL, 0); 1278 1279 /* 1280 * Size the clean queue according to the amount of buffer space. 1281 * One queue per-256mb up to the max. More queues gives better 1282 * concurrency but less accurate LRU. 1283 */ 1284 buf_domains = MIN(howmany(maxbufspace, 256*1024*1024), BUF_DOMAINS); 1285 for (i = 0 ; i < buf_domains; i++) { 1286 struct bufdomain *bd; 1287 1288 bd = &bdomain[i]; 1289 bd_init(bd); 1290 bd->bd_freebuffers = nbuf / buf_domains; 1291 bd->bd_hifreebuffers = hifreebuffers / buf_domains; 1292 bd->bd_lofreebuffers = lofreebuffers / buf_domains; 1293 bd->bd_bufspace = 0; 1294 bd->bd_maxbufspace = maxbufspace / buf_domains; 1295 bd->bd_hibufspace = hibufspace / buf_domains; 1296 bd->bd_lobufspace = lobufspace / buf_domains; 1297 bd->bd_bufspacethresh = bufspacethresh / buf_domains; 1298 bd->bd_numdirtybuffers = 0; 1299 bd->bd_hidirtybuffers = hidirtybuffers / buf_domains; 1300 bd->bd_lodirtybuffers = lodirtybuffers / buf_domains; 1301 bd->bd_dirtybufthresh = dirtybufthresh / buf_domains; 1302 /* Don't allow more than 2% of bufs in the per-cpu caches. */ 1303 bd->bd_lim = nbuf / buf_domains / 50 / mp_ncpus; 1304 } 1305 getnewbufcalls = counter_u64_alloc(M_WAITOK); 1306 getnewbufrestarts = counter_u64_alloc(M_WAITOK); 1307 mappingrestarts = counter_u64_alloc(M_WAITOK); 1308 numbufallocfails = counter_u64_alloc(M_WAITOK); 1309 notbufdflushes = counter_u64_alloc(M_WAITOK); 1310 buffreekvacnt = counter_u64_alloc(M_WAITOK); 1311 bufdefragcnt = counter_u64_alloc(M_WAITOK); 1312 bufkvaspace = counter_u64_alloc(M_WAITOK); 1313 } 1314 1315 #ifdef INVARIANTS 1316 static inline void 1317 vfs_buf_check_mapped(struct buf *bp) 1318 { 1319 1320 KASSERT(bp->b_kvabase != unmapped_buf, 1321 ("mapped buf: b_kvabase was not updated %p", bp)); 1322 KASSERT(bp->b_data != unmapped_buf, 1323 ("mapped buf: b_data was not updated %p", bp)); 1324 KASSERT(bp->b_data < unmapped_buf || bp->b_data >= unmapped_buf + 1325 maxphys, ("b_data + b_offset unmapped %p", bp)); 1326 } 1327 1328 static inline void 1329 vfs_buf_check_unmapped(struct buf *bp) 1330 { 1331 1332 KASSERT(bp->b_data == unmapped_buf, 1333 ("unmapped buf: corrupted b_data %p", bp)); 1334 } 1335 1336 #define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp) 1337 #define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp) 1338 #else 1339 #define BUF_CHECK_MAPPED(bp) do {} while (0) 1340 #define BUF_CHECK_UNMAPPED(bp) do {} while (0) 1341 #endif 1342 1343 static int 1344 isbufbusy(struct buf *bp) 1345 { 1346 if (((bp->b_flags & B_INVAL) == 0 && BUF_ISLOCKED(bp)) || 1347 ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)) 1348 return (1); 1349 return (0); 1350 } 1351 1352 /* 1353 * Shutdown the system cleanly to prepare for reboot, halt, or power off. 1354 */ 1355 void 1356 bufshutdown(int show_busybufs) 1357 { 1358 static int first_buf_printf = 1; 1359 struct buf *bp; 1360 int i, iter, nbusy, pbusy; 1361 #ifndef PREEMPTION 1362 int subiter; 1363 #endif 1364 1365 /* 1366 * Sync filesystems for shutdown 1367 */ 1368 wdog_kern_pat(WD_LASTVAL); 1369 kern_sync(curthread); 1370 1371 /* 1372 * With soft updates, some buffers that are 1373 * written will be remarked as dirty until other 1374 * buffers are written. 1375 */ 1376 for (iter = pbusy = 0; iter < 20; iter++) { 1377 nbusy = 0; 1378 for (i = nbuf - 1; i >= 0; i--) { 1379 bp = nbufp(i); 1380 if (isbufbusy(bp)) 1381 nbusy++; 1382 } 1383 if (nbusy == 0) { 1384 if (first_buf_printf) 1385 printf("All buffers synced."); 1386 break; 1387 } 1388 if (first_buf_printf) { 1389 printf("Syncing disks, buffers remaining... "); 1390 first_buf_printf = 0; 1391 } 1392 printf("%d ", nbusy); 1393 if (nbusy < pbusy) 1394 iter = 0; 1395 pbusy = nbusy; 1396 1397 wdog_kern_pat(WD_LASTVAL); 1398 kern_sync(curthread); 1399 1400 #ifdef PREEMPTION 1401 /* 1402 * Spin for a while to allow interrupt threads to run. 1403 */ 1404 DELAY(50000 * iter); 1405 #else 1406 /* 1407 * Context switch several times to allow interrupt 1408 * threads to run. 1409 */ 1410 for (subiter = 0; subiter < 50 * iter; subiter++) { 1411 thread_lock(curthread); 1412 mi_switch(SW_VOL); 1413 DELAY(1000); 1414 } 1415 #endif 1416 } 1417 printf("\n"); 1418 /* 1419 * Count only busy local buffers to prevent forcing 1420 * a fsck if we're just a client of a wedged NFS server 1421 */ 1422 nbusy = 0; 1423 for (i = nbuf - 1; i >= 0; i--) { 1424 bp = nbufp(i); 1425 if (isbufbusy(bp)) { 1426 #if 0 1427 /* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */ 1428 if (bp->b_dev == NULL) { 1429 TAILQ_REMOVE(&mountlist, 1430 bp->b_vp->v_mount, mnt_list); 1431 continue; 1432 } 1433 #endif 1434 nbusy++; 1435 if (show_busybufs > 0) { 1436 printf( 1437 "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:", 1438 nbusy, bp, bp->b_vp, bp->b_flags, 1439 (intmax_t)bp->b_blkno, 1440 (intmax_t)bp->b_lblkno); 1441 BUF_LOCKPRINTINFO(bp); 1442 if (show_busybufs > 1) 1443 vn_printf(bp->b_vp, 1444 "vnode content: "); 1445 } 1446 } 1447 } 1448 if (nbusy) { 1449 /* 1450 * Failed to sync all blocks. Indicate this and don't 1451 * unmount filesystems (thus forcing an fsck on reboot). 1452 */ 1453 printf("Giving up on %d buffers\n", nbusy); 1454 DELAY(5000000); /* 5 seconds */ 1455 swapoff_all(); 1456 } else { 1457 if (!first_buf_printf) 1458 printf("Final sync complete\n"); 1459 1460 /* 1461 * Unmount filesystems and perform swapoff, to quiesce 1462 * the system as much as possible. In particular, no 1463 * I/O should be initiated from top levels since it 1464 * might be abruptly terminated by reset, or otherwise 1465 * erronously handled because other parts of the 1466 * system are disabled. 1467 * 1468 * Swapoff before unmount, because file-backed swap is 1469 * non-operational after unmount of the underlying 1470 * filesystem. 1471 */ 1472 if (!KERNEL_PANICKED()) { 1473 swapoff_all(); 1474 vfs_unmountall(); 1475 } 1476 } 1477 DELAY(100000); /* wait for console output to finish */ 1478 } 1479 1480 static void 1481 bpmap_qenter(struct buf *bp) 1482 { 1483 1484 BUF_CHECK_MAPPED(bp); 1485 1486 /* 1487 * bp->b_data is relative to bp->b_offset, but 1488 * bp->b_offset may be offset into the first page. 1489 */ 1490 bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data); 1491 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 1492 bp->b_data = (caddr_t)((vm_offset_t)bp->b_data | 1493 (vm_offset_t)(bp->b_offset & PAGE_MASK)); 1494 } 1495 1496 static inline struct bufdomain * 1497 bufdomain(struct buf *bp) 1498 { 1499 1500 return (&bdomain[bp->b_domain]); 1501 } 1502 1503 static struct bufqueue * 1504 bufqueue(struct buf *bp) 1505 { 1506 1507 switch (bp->b_qindex) { 1508 case QUEUE_NONE: 1509 /* FALLTHROUGH */ 1510 case QUEUE_SENTINEL: 1511 return (NULL); 1512 case QUEUE_EMPTY: 1513 return (&bqempty); 1514 case QUEUE_DIRTY: 1515 return (&bufdomain(bp)->bd_dirtyq); 1516 case QUEUE_CLEAN: 1517 return (&bufdomain(bp)->bd_subq[bp->b_subqueue]); 1518 default: 1519 break; 1520 } 1521 panic("bufqueue(%p): Unhandled type %d\n", bp, bp->b_qindex); 1522 } 1523 1524 /* 1525 * Return the locked bufqueue that bp is a member of. 1526 */ 1527 static struct bufqueue * 1528 bufqueue_acquire(struct buf *bp) 1529 { 1530 struct bufqueue *bq, *nbq; 1531 1532 /* 1533 * bp can be pushed from a per-cpu queue to the 1534 * cleanq while we're waiting on the lock. Retry 1535 * if the queues don't match. 1536 */ 1537 bq = bufqueue(bp); 1538 BQ_LOCK(bq); 1539 for (;;) { 1540 nbq = bufqueue(bp); 1541 if (bq == nbq) 1542 break; 1543 BQ_UNLOCK(bq); 1544 BQ_LOCK(nbq); 1545 bq = nbq; 1546 } 1547 return (bq); 1548 } 1549 1550 /* 1551 * binsfree: 1552 * 1553 * Insert the buffer into the appropriate free list. Requires a 1554 * locked buffer on entry and buffer is unlocked before return. 1555 */ 1556 static void 1557 binsfree(struct buf *bp, int qindex) 1558 { 1559 struct bufdomain *bd; 1560 struct bufqueue *bq; 1561 1562 KASSERT(qindex == QUEUE_CLEAN || qindex == QUEUE_DIRTY, 1563 ("binsfree: Invalid qindex %d", qindex)); 1564 BUF_ASSERT_XLOCKED(bp); 1565 1566 /* 1567 * Handle delayed bremfree() processing. 1568 */ 1569 if (bp->b_flags & B_REMFREE) { 1570 if (bp->b_qindex == qindex) { 1571 bp->b_flags |= B_REUSE; 1572 bp->b_flags &= ~B_REMFREE; 1573 BUF_UNLOCK(bp); 1574 return; 1575 } 1576 bq = bufqueue_acquire(bp); 1577 bq_remove(bq, bp); 1578 BQ_UNLOCK(bq); 1579 } 1580 bd = bufdomain(bp); 1581 if (qindex == QUEUE_CLEAN) { 1582 if (bd->bd_lim != 0) 1583 bq = &bd->bd_subq[PCPU_GET(cpuid)]; 1584 else 1585 bq = bd->bd_cleanq; 1586 } else 1587 bq = &bd->bd_dirtyq; 1588 bq_insert(bq, bp, true); 1589 } 1590 1591 /* 1592 * buf_free: 1593 * 1594 * Free a buffer to the buf zone once it no longer has valid contents. 1595 */ 1596 static void 1597 buf_free(struct buf *bp) 1598 { 1599 1600 if (bp->b_flags & B_REMFREE) 1601 bremfreef(bp); 1602 if (bp->b_vflags & BV_BKGRDINPROG) 1603 panic("losing buffer 1"); 1604 if (bp->b_rcred != NOCRED) { 1605 crfree(bp->b_rcred); 1606 bp->b_rcred = NOCRED; 1607 } 1608 if (bp->b_wcred != NOCRED) { 1609 crfree(bp->b_wcred); 1610 bp->b_wcred = NOCRED; 1611 } 1612 if (!LIST_EMPTY(&bp->b_dep)) 1613 buf_deallocate(bp); 1614 bufkva_free(bp); 1615 atomic_add_int(&bufdomain(bp)->bd_freebuffers, 1); 1616 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1617 BUF_UNLOCK(bp); 1618 uma_zfree(buf_zone, bp); 1619 } 1620 1621 /* 1622 * buf_import: 1623 * 1624 * Import bufs into the uma cache from the buf list. The system still 1625 * expects a static array of bufs and much of the synchronization 1626 * around bufs assumes type stable storage. As a result, UMA is used 1627 * only as a per-cpu cache of bufs still maintained on a global list. 1628 */ 1629 static int 1630 buf_import(void *arg, void **store, int cnt, int domain, int flags) 1631 { 1632 struct buf *bp; 1633 int i; 1634 1635 BQ_LOCK(&bqempty); 1636 for (i = 0; i < cnt; i++) { 1637 bp = TAILQ_FIRST(&bqempty.bq_queue); 1638 if (bp == NULL) 1639 break; 1640 bq_remove(&bqempty, bp); 1641 store[i] = bp; 1642 } 1643 BQ_UNLOCK(&bqempty); 1644 1645 return (i); 1646 } 1647 1648 /* 1649 * buf_release: 1650 * 1651 * Release bufs from the uma cache back to the buffer queues. 1652 */ 1653 static void 1654 buf_release(void *arg, void **store, int cnt) 1655 { 1656 struct bufqueue *bq; 1657 struct buf *bp; 1658 int i; 1659 1660 bq = &bqempty; 1661 BQ_LOCK(bq); 1662 for (i = 0; i < cnt; i++) { 1663 bp = store[i]; 1664 /* Inline bq_insert() to batch locking. */ 1665 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1666 bp->b_flags &= ~(B_AGE | B_REUSE); 1667 bq->bq_len++; 1668 bp->b_qindex = bq->bq_index; 1669 } 1670 BQ_UNLOCK(bq); 1671 } 1672 1673 /* 1674 * buf_alloc: 1675 * 1676 * Allocate an empty buffer header. 1677 */ 1678 static struct buf * 1679 buf_alloc(struct bufdomain *bd) 1680 { 1681 struct buf *bp; 1682 int freebufs, error; 1683 1684 /* 1685 * We can only run out of bufs in the buf zone if the average buf 1686 * is less than BKVASIZE. In this case the actual wait/block will 1687 * come from buf_reycle() failing to flush one of these small bufs. 1688 */ 1689 bp = NULL; 1690 freebufs = atomic_fetchadd_int(&bd->bd_freebuffers, -1); 1691 if (freebufs > 0) 1692 bp = uma_zalloc(buf_zone, M_NOWAIT); 1693 if (bp == NULL) { 1694 atomic_add_int(&bd->bd_freebuffers, 1); 1695 bufspace_daemon_wakeup(bd); 1696 counter_u64_add(numbufallocfails, 1); 1697 return (NULL); 1698 } 1699 /* 1700 * Wake-up the bufspace daemon on transition below threshold. 1701 */ 1702 if (freebufs == bd->bd_lofreebuffers) 1703 bufspace_daemon_wakeup(bd); 1704 1705 error = BUF_LOCK(bp, LK_EXCLUSIVE, NULL); 1706 KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, 1707 error)); 1708 (void)error; 1709 1710 KASSERT(bp->b_vp == NULL, 1711 ("bp: %p still has vnode %p.", bp, bp->b_vp)); 1712 KASSERT((bp->b_flags & (B_DELWRI | B_NOREUSE)) == 0, 1713 ("invalid buffer %p flags %#x", bp, bp->b_flags)); 1714 KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0, 1715 ("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags)); 1716 KASSERT(bp->b_npages == 0, 1717 ("bp: %p still has %d vm pages\n", bp, bp->b_npages)); 1718 KASSERT(bp->b_kvasize == 0, ("bp: %p still has kva\n", bp)); 1719 KASSERT(bp->b_bufsize == 0, ("bp: %p still has bufspace\n", bp)); 1720 MPASS((bp->b_flags & B_MAXPHYS) == 0); 1721 1722 bp->b_domain = BD_DOMAIN(bd); 1723 bp->b_flags = 0; 1724 bp->b_ioflags = 0; 1725 bp->b_xflags = 0; 1726 bp->b_vflags = 0; 1727 bp->b_vp = NULL; 1728 bp->b_blkno = bp->b_lblkno = 0; 1729 bp->b_offset = NOOFFSET; 1730 bp->b_iodone = 0; 1731 bp->b_error = 0; 1732 bp->b_resid = 0; 1733 bp->b_bcount = 0; 1734 bp->b_npages = 0; 1735 bp->b_dirtyoff = bp->b_dirtyend = 0; 1736 bp->b_bufobj = NULL; 1737 bp->b_data = bp->b_kvabase = unmapped_buf; 1738 bp->b_fsprivate1 = NULL; 1739 bp->b_fsprivate2 = NULL; 1740 bp->b_fsprivate3 = NULL; 1741 LIST_INIT(&bp->b_dep); 1742 1743 return (bp); 1744 } 1745 1746 /* 1747 * buf_recycle: 1748 * 1749 * Free a buffer from the given bufqueue. kva controls whether the 1750 * freed buf must own some kva resources. This is used for 1751 * defragmenting. 1752 */ 1753 static int 1754 buf_recycle(struct bufdomain *bd, bool kva) 1755 { 1756 struct bufqueue *bq; 1757 struct buf *bp, *nbp; 1758 1759 if (kva) 1760 counter_u64_add(bufdefragcnt, 1); 1761 nbp = NULL; 1762 bq = bd->bd_cleanq; 1763 BQ_LOCK(bq); 1764 KASSERT(BQ_LOCKPTR(bq) == BD_LOCKPTR(bd), 1765 ("buf_recycle: Locks don't match")); 1766 nbp = TAILQ_FIRST(&bq->bq_queue); 1767 1768 /* 1769 * Run scan, possibly freeing data and/or kva mappings on the fly 1770 * depending. 1771 */ 1772 while ((bp = nbp) != NULL) { 1773 /* 1774 * Calculate next bp (we can only use it if we do not 1775 * release the bqlock). 1776 */ 1777 nbp = TAILQ_NEXT(bp, b_freelist); 1778 1779 /* 1780 * If we are defragging then we need a buffer with 1781 * some kva to reclaim. 1782 */ 1783 if (kva && bp->b_kvasize == 0) 1784 continue; 1785 1786 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 1787 continue; 1788 1789 /* 1790 * Implement a second chance algorithm for frequently 1791 * accessed buffers. 1792 */ 1793 if ((bp->b_flags & B_REUSE) != 0) { 1794 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1795 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1796 bp->b_flags &= ~B_REUSE; 1797 BUF_UNLOCK(bp); 1798 continue; 1799 } 1800 1801 /* 1802 * Skip buffers with background writes in progress. 1803 */ 1804 if ((bp->b_vflags & BV_BKGRDINPROG) != 0) { 1805 BUF_UNLOCK(bp); 1806 continue; 1807 } 1808 1809 KASSERT(bp->b_qindex == QUEUE_CLEAN, 1810 ("buf_recycle: inconsistent queue %d bp %p", 1811 bp->b_qindex, bp)); 1812 KASSERT(bp->b_domain == BD_DOMAIN(bd), 1813 ("getnewbuf: queue domain %d doesn't match request %d", 1814 bp->b_domain, (int)BD_DOMAIN(bd))); 1815 /* 1816 * NOTE: nbp is now entirely invalid. We can only restart 1817 * the scan from this point on. 1818 */ 1819 bq_remove(bq, bp); 1820 BQ_UNLOCK(bq); 1821 1822 /* 1823 * Requeue the background write buffer with error and 1824 * restart the scan. 1825 */ 1826 if ((bp->b_vflags & BV_BKGRDERR) != 0) { 1827 bqrelse(bp); 1828 BQ_LOCK(bq); 1829 nbp = TAILQ_FIRST(&bq->bq_queue); 1830 continue; 1831 } 1832 bp->b_flags |= B_INVAL; 1833 brelse(bp); 1834 return (0); 1835 } 1836 bd->bd_wanted = 1; 1837 BQ_UNLOCK(bq); 1838 1839 return (ENOBUFS); 1840 } 1841 1842 /* 1843 * bremfree: 1844 * 1845 * Mark the buffer for removal from the appropriate free list. 1846 * 1847 */ 1848 void 1849 bremfree(struct buf *bp) 1850 { 1851 1852 CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 1853 KASSERT((bp->b_flags & B_REMFREE) == 0, 1854 ("bremfree: buffer %p already marked for delayed removal.", bp)); 1855 KASSERT(bp->b_qindex != QUEUE_NONE, 1856 ("bremfree: buffer %p not on a queue.", bp)); 1857 BUF_ASSERT_XLOCKED(bp); 1858 1859 bp->b_flags |= B_REMFREE; 1860 } 1861 1862 /* 1863 * bremfreef: 1864 * 1865 * Force an immediate removal from a free list. Used only in nfs when 1866 * it abuses the b_freelist pointer. 1867 */ 1868 void 1869 bremfreef(struct buf *bp) 1870 { 1871 struct bufqueue *bq; 1872 1873 bq = bufqueue_acquire(bp); 1874 bq_remove(bq, bp); 1875 BQ_UNLOCK(bq); 1876 } 1877 1878 static void 1879 bq_init(struct bufqueue *bq, int qindex, int subqueue, const char *lockname) 1880 { 1881 1882 mtx_init(&bq->bq_lock, lockname, NULL, MTX_DEF); 1883 TAILQ_INIT(&bq->bq_queue); 1884 bq->bq_len = 0; 1885 bq->bq_index = qindex; 1886 bq->bq_subqueue = subqueue; 1887 } 1888 1889 static void 1890 bd_init(struct bufdomain *bd) 1891 { 1892 int i; 1893 1894 bd->bd_cleanq = &bd->bd_subq[mp_maxid + 1]; 1895 bq_init(bd->bd_cleanq, QUEUE_CLEAN, mp_maxid + 1, "bufq clean lock"); 1896 bq_init(&bd->bd_dirtyq, QUEUE_DIRTY, -1, "bufq dirty lock"); 1897 for (i = 0; i <= mp_maxid; i++) 1898 bq_init(&bd->bd_subq[i], QUEUE_CLEAN, i, 1899 "bufq clean subqueue lock"); 1900 mtx_init(&bd->bd_run_lock, "bufspace daemon run lock", NULL, MTX_DEF); 1901 } 1902 1903 /* 1904 * bq_remove: 1905 * 1906 * Removes a buffer from the free list, must be called with the 1907 * correct qlock held. 1908 */ 1909 static void 1910 bq_remove(struct bufqueue *bq, struct buf *bp) 1911 { 1912 1913 CTR3(KTR_BUF, "bq_remove(%p) vp %p flags %X", 1914 bp, bp->b_vp, bp->b_flags); 1915 KASSERT(bp->b_qindex != QUEUE_NONE, 1916 ("bq_remove: buffer %p not on a queue.", bp)); 1917 KASSERT(bufqueue(bp) == bq, 1918 ("bq_remove: Remove buffer %p from wrong queue.", bp)); 1919 1920 BQ_ASSERT_LOCKED(bq); 1921 if (bp->b_qindex != QUEUE_EMPTY) { 1922 BUF_ASSERT_XLOCKED(bp); 1923 } 1924 KASSERT(bq->bq_len >= 1, 1925 ("queue %d underflow", bp->b_qindex)); 1926 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1927 bq->bq_len--; 1928 bp->b_qindex = QUEUE_NONE; 1929 bp->b_flags &= ~(B_REMFREE | B_REUSE); 1930 } 1931 1932 static void 1933 bd_flush(struct bufdomain *bd, struct bufqueue *bq) 1934 { 1935 struct buf *bp; 1936 1937 BQ_ASSERT_LOCKED(bq); 1938 if (bq != bd->bd_cleanq) { 1939 BD_LOCK(bd); 1940 while ((bp = TAILQ_FIRST(&bq->bq_queue)) != NULL) { 1941 TAILQ_REMOVE(&bq->bq_queue, bp, b_freelist); 1942 TAILQ_INSERT_TAIL(&bd->bd_cleanq->bq_queue, bp, 1943 b_freelist); 1944 bp->b_subqueue = bd->bd_cleanq->bq_subqueue; 1945 } 1946 bd->bd_cleanq->bq_len += bq->bq_len; 1947 bq->bq_len = 0; 1948 } 1949 if (bd->bd_wanted) { 1950 bd->bd_wanted = 0; 1951 wakeup(&bd->bd_wanted); 1952 } 1953 if (bq != bd->bd_cleanq) 1954 BD_UNLOCK(bd); 1955 } 1956 1957 static int 1958 bd_flushall(struct bufdomain *bd) 1959 { 1960 struct bufqueue *bq; 1961 int flushed; 1962 int i; 1963 1964 if (bd->bd_lim == 0) 1965 return (0); 1966 flushed = 0; 1967 for (i = 0; i <= mp_maxid; i++) { 1968 bq = &bd->bd_subq[i]; 1969 if (bq->bq_len == 0) 1970 continue; 1971 BQ_LOCK(bq); 1972 bd_flush(bd, bq); 1973 BQ_UNLOCK(bq); 1974 flushed++; 1975 } 1976 1977 return (flushed); 1978 } 1979 1980 static void 1981 bq_insert(struct bufqueue *bq, struct buf *bp, bool unlock) 1982 { 1983 struct bufdomain *bd; 1984 1985 if (bp->b_qindex != QUEUE_NONE) 1986 panic("bq_insert: free buffer %p onto another queue?", bp); 1987 1988 bd = bufdomain(bp); 1989 if (bp->b_flags & B_AGE) { 1990 /* Place this buf directly on the real queue. */ 1991 if (bq->bq_index == QUEUE_CLEAN) 1992 bq = bd->bd_cleanq; 1993 BQ_LOCK(bq); 1994 TAILQ_INSERT_HEAD(&bq->bq_queue, bp, b_freelist); 1995 } else { 1996 BQ_LOCK(bq); 1997 TAILQ_INSERT_TAIL(&bq->bq_queue, bp, b_freelist); 1998 } 1999 bp->b_flags &= ~(B_AGE | B_REUSE); 2000 bq->bq_len++; 2001 bp->b_qindex = bq->bq_index; 2002 bp->b_subqueue = bq->bq_subqueue; 2003 2004 /* 2005 * Unlock before we notify so that we don't wakeup a waiter that 2006 * fails a trylock on the buf and sleeps again. 2007 */ 2008 if (unlock) 2009 BUF_UNLOCK(bp); 2010 2011 if (bp->b_qindex == QUEUE_CLEAN) { 2012 /* 2013 * Flush the per-cpu queue and notify any waiters. 2014 */ 2015 if (bd->bd_wanted || (bq != bd->bd_cleanq && 2016 bq->bq_len >= bd->bd_lim)) 2017 bd_flush(bd, bq); 2018 } 2019 BQ_UNLOCK(bq); 2020 } 2021 2022 /* 2023 * bufkva_free: 2024 * 2025 * Free the kva allocation for a buffer. 2026 * 2027 */ 2028 static void 2029 bufkva_free(struct buf *bp) 2030 { 2031 2032 #ifdef INVARIANTS 2033 if (bp->b_kvasize == 0) { 2034 KASSERT(bp->b_kvabase == unmapped_buf && 2035 bp->b_data == unmapped_buf, 2036 ("Leaked KVA space on %p", bp)); 2037 } else if (buf_mapped(bp)) 2038 BUF_CHECK_MAPPED(bp); 2039 else 2040 BUF_CHECK_UNMAPPED(bp); 2041 #endif 2042 if (bp->b_kvasize == 0) 2043 return; 2044 2045 vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, bp->b_kvasize); 2046 counter_u64_add(bufkvaspace, -bp->b_kvasize); 2047 counter_u64_add(buffreekvacnt, 1); 2048 bp->b_data = bp->b_kvabase = unmapped_buf; 2049 bp->b_kvasize = 0; 2050 } 2051 2052 /* 2053 * bufkva_alloc: 2054 * 2055 * Allocate the buffer KVA and set b_kvasize and b_kvabase. 2056 */ 2057 static int 2058 bufkva_alloc(struct buf *bp, int maxsize, int gbflags) 2059 { 2060 vm_offset_t addr; 2061 int error; 2062 2063 KASSERT((gbflags & GB_UNMAPPED) == 0 || (gbflags & GB_KVAALLOC) != 0, 2064 ("Invalid gbflags 0x%x in %s", gbflags, __func__)); 2065 MPASS((bp->b_flags & B_MAXPHYS) == 0); 2066 KASSERT(maxsize <= maxbcachebuf, 2067 ("bufkva_alloc kva too large %d %u", maxsize, maxbcachebuf)); 2068 2069 bufkva_free(bp); 2070 2071 addr = 0; 2072 error = vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr); 2073 if (error != 0) { 2074 /* 2075 * Buffer map is too fragmented. Request the caller 2076 * to defragment the map. 2077 */ 2078 return (error); 2079 } 2080 bp->b_kvabase = (caddr_t)addr; 2081 bp->b_kvasize = maxsize; 2082 counter_u64_add(bufkvaspace, bp->b_kvasize); 2083 if ((gbflags & GB_UNMAPPED) != 0) { 2084 bp->b_data = unmapped_buf; 2085 BUF_CHECK_UNMAPPED(bp); 2086 } else { 2087 bp->b_data = bp->b_kvabase; 2088 BUF_CHECK_MAPPED(bp); 2089 } 2090 return (0); 2091 } 2092 2093 /* 2094 * bufkva_reclaim: 2095 * 2096 * Reclaim buffer kva by freeing buffers holding kva. This is a vmem 2097 * callback that fires to avoid returning failure. 2098 */ 2099 static void 2100 bufkva_reclaim(vmem_t *vmem, int flags) 2101 { 2102 bool done; 2103 int q; 2104 int i; 2105 2106 done = false; 2107 for (i = 0; i < 5; i++) { 2108 for (q = 0; q < buf_domains; q++) 2109 if (buf_recycle(&bdomain[q], true) != 0) 2110 done = true; 2111 if (done) 2112 break; 2113 } 2114 return; 2115 } 2116 2117 /* 2118 * Attempt to initiate asynchronous I/O on read-ahead blocks. We must 2119 * clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set, 2120 * the buffer is valid and we do not have to do anything. 2121 */ 2122 static void 2123 breada(struct vnode * vp, daddr_t * rablkno, int * rabsize, int cnt, 2124 struct ucred * cred, int flags, void (*ckhashfunc)(struct buf *)) 2125 { 2126 struct buf *rabp; 2127 struct thread *td; 2128 int i; 2129 2130 td = curthread; 2131 2132 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 2133 if (inmem(vp, *rablkno)) 2134 continue; 2135 rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0); 2136 if ((rabp->b_flags & B_CACHE) != 0) { 2137 brelse(rabp); 2138 continue; 2139 } 2140 #ifdef RACCT 2141 if (racct_enable) { 2142 PROC_LOCK(curproc); 2143 racct_add_buf(curproc, rabp, 0); 2144 PROC_UNLOCK(curproc); 2145 } 2146 #endif /* RACCT */ 2147 td->td_ru.ru_inblock++; 2148 rabp->b_flags |= B_ASYNC; 2149 rabp->b_flags &= ~B_INVAL; 2150 if ((flags & GB_CKHASH) != 0) { 2151 rabp->b_flags |= B_CKHASH; 2152 rabp->b_ckhashcalc = ckhashfunc; 2153 } 2154 rabp->b_ioflags &= ~BIO_ERROR; 2155 rabp->b_iocmd = BIO_READ; 2156 if (rabp->b_rcred == NOCRED && cred != NOCRED) 2157 rabp->b_rcred = crhold(cred); 2158 vfs_busy_pages(rabp, 0); 2159 BUF_KERNPROC(rabp); 2160 rabp->b_iooffset = dbtob(rabp->b_blkno); 2161 bstrategy(rabp); 2162 } 2163 } 2164 2165 /* 2166 * Entry point for bread() and breadn() via #defines in sys/buf.h. 2167 * 2168 * Get a buffer with the specified data. Look in the cache first. We 2169 * must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE 2170 * is set, the buffer is valid and we do not have to do anything, see 2171 * getblk(). Also starts asynchronous I/O on read-ahead blocks. 2172 * 2173 * Always return a NULL buffer pointer (in bpp) when returning an error. 2174 * 2175 * The blkno parameter is the logical block being requested. Normally 2176 * the mapping of logical block number to disk block address is done 2177 * by calling VOP_BMAP(). However, if the mapping is already known, the 2178 * disk block address can be passed using the dblkno parameter. If the 2179 * disk block address is not known, then the same value should be passed 2180 * for blkno and dblkno. 2181 */ 2182 int 2183 breadn_flags(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, 2184 daddr_t *rablkno, int *rabsize, int cnt, struct ucred *cred, int flags, 2185 void (*ckhashfunc)(struct buf *), struct buf **bpp) 2186 { 2187 struct buf *bp; 2188 struct thread *td; 2189 int error, readwait, rv; 2190 2191 CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size); 2192 td = curthread; 2193 /* 2194 * Can only return NULL if GB_LOCK_NOWAIT or GB_SPARSE flags 2195 * are specified. 2196 */ 2197 error = getblkx(vp, blkno, dblkno, size, 0, 0, flags, &bp); 2198 if (error != 0) { 2199 *bpp = NULL; 2200 return (error); 2201 } 2202 KASSERT(blkno == bp->b_lblkno, 2203 ("getblkx returned buffer for blkno %jd instead of blkno %jd", 2204 (intmax_t)bp->b_lblkno, (intmax_t)blkno)); 2205 flags &= ~GB_NOSPARSE; 2206 *bpp = bp; 2207 2208 /* 2209 * If not found in cache, do some I/O 2210 */ 2211 readwait = 0; 2212 if ((bp->b_flags & B_CACHE) == 0) { 2213 #ifdef RACCT 2214 if (racct_enable) { 2215 PROC_LOCK(td->td_proc); 2216 racct_add_buf(td->td_proc, bp, 0); 2217 PROC_UNLOCK(td->td_proc); 2218 } 2219 #endif /* RACCT */ 2220 td->td_ru.ru_inblock++; 2221 bp->b_iocmd = BIO_READ; 2222 bp->b_flags &= ~B_INVAL; 2223 if ((flags & GB_CKHASH) != 0) { 2224 bp->b_flags |= B_CKHASH; 2225 bp->b_ckhashcalc = ckhashfunc; 2226 } 2227 if ((flags & GB_CVTENXIO) != 0) 2228 bp->b_xflags |= BX_CVTENXIO; 2229 bp->b_ioflags &= ~BIO_ERROR; 2230 if (bp->b_rcred == NOCRED && cred != NOCRED) 2231 bp->b_rcred = crhold(cred); 2232 vfs_busy_pages(bp, 0); 2233 bp->b_iooffset = dbtob(bp->b_blkno); 2234 bstrategy(bp); 2235 ++readwait; 2236 } 2237 2238 /* 2239 * Attempt to initiate asynchronous I/O on read-ahead blocks. 2240 */ 2241 breada(vp, rablkno, rabsize, cnt, cred, flags, ckhashfunc); 2242 2243 rv = 0; 2244 if (readwait) { 2245 rv = bufwait(bp); 2246 if (rv != 0) { 2247 brelse(bp); 2248 *bpp = NULL; 2249 } 2250 } 2251 return (rv); 2252 } 2253 2254 /* 2255 * Write, release buffer on completion. (Done by iodone 2256 * if async). Do not bother writing anything if the buffer 2257 * is invalid. 2258 * 2259 * Note that we set B_CACHE here, indicating that buffer is 2260 * fully valid and thus cacheable. This is true even of NFS 2261 * now so we set it generally. This could be set either here 2262 * or in biodone() since the I/O is synchronous. We put it 2263 * here. 2264 */ 2265 int 2266 bufwrite(struct buf *bp) 2267 { 2268 int oldflags; 2269 struct vnode *vp; 2270 long space; 2271 int vp_md; 2272 2273 CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2274 if ((bp->b_bufobj->bo_flag & BO_DEAD) != 0) { 2275 bp->b_flags |= B_INVAL | B_RELBUF; 2276 bp->b_flags &= ~B_CACHE; 2277 brelse(bp); 2278 return (ENXIO); 2279 } 2280 if (bp->b_flags & B_INVAL) { 2281 brelse(bp); 2282 return (0); 2283 } 2284 2285 if (bp->b_flags & B_BARRIER) 2286 atomic_add_long(&barrierwrites, 1); 2287 2288 oldflags = bp->b_flags; 2289 2290 KASSERT(!(bp->b_vflags & BV_BKGRDINPROG), 2291 ("FFS background buffer should not get here %p", bp)); 2292 2293 vp = bp->b_vp; 2294 if (vp) 2295 vp_md = vp->v_vflag & VV_MD; 2296 else 2297 vp_md = 0; 2298 2299 /* 2300 * Mark the buffer clean. Increment the bufobj write count 2301 * before bundirty() call, to prevent other thread from seeing 2302 * empty dirty list and zero counter for writes in progress, 2303 * falsely indicating that the bufobj is clean. 2304 */ 2305 bufobj_wref(bp->b_bufobj); 2306 bundirty(bp); 2307 2308 bp->b_flags &= ~B_DONE; 2309 bp->b_ioflags &= ~BIO_ERROR; 2310 bp->b_flags |= B_CACHE; 2311 bp->b_iocmd = BIO_WRITE; 2312 2313 vfs_busy_pages(bp, 1); 2314 2315 /* 2316 * Normal bwrites pipeline writes 2317 */ 2318 bp->b_runningbufspace = bp->b_bufsize; 2319 space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace); 2320 2321 #ifdef RACCT 2322 if (racct_enable) { 2323 PROC_LOCK(curproc); 2324 racct_add_buf(curproc, bp, 1); 2325 PROC_UNLOCK(curproc); 2326 } 2327 #endif /* RACCT */ 2328 curthread->td_ru.ru_oublock++; 2329 if (oldflags & B_ASYNC) 2330 BUF_KERNPROC(bp); 2331 bp->b_iooffset = dbtob(bp->b_blkno); 2332 buf_track(bp, __func__); 2333 bstrategy(bp); 2334 2335 if ((oldflags & B_ASYNC) == 0) { 2336 int rtval = bufwait(bp); 2337 brelse(bp); 2338 return (rtval); 2339 } else if (space > hirunningspace) { 2340 /* 2341 * don't allow the async write to saturate the I/O 2342 * system. We will not deadlock here because 2343 * we are blocking waiting for I/O that is already in-progress 2344 * to complete. We do not block here if it is the update 2345 * or syncer daemon trying to clean up as that can lead 2346 * to deadlock. 2347 */ 2348 if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md) 2349 waitrunningbufspace(); 2350 } 2351 2352 return (0); 2353 } 2354 2355 void 2356 bufbdflush(struct bufobj *bo, struct buf *bp) 2357 { 2358 struct buf *nbp; 2359 struct bufdomain *bd; 2360 2361 bd = &bdomain[bo->bo_domain]; 2362 if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh + 10) { 2363 (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); 2364 altbufferflushes++; 2365 } else if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh) { 2366 BO_LOCK(bo); 2367 /* 2368 * Try to find a buffer to flush. 2369 */ 2370 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2371 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2372 BUF_LOCK(nbp, 2373 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2374 continue; 2375 if (bp == nbp) 2376 panic("bdwrite: found ourselves"); 2377 BO_UNLOCK(bo); 2378 /* Don't countdeps with the bo lock held. */ 2379 if (buf_countdeps(nbp, 0)) { 2380 BO_LOCK(bo); 2381 BUF_UNLOCK(nbp); 2382 continue; 2383 } 2384 if (nbp->b_flags & B_CLUSTEROK) { 2385 vfs_bio_awrite(nbp); 2386 } else { 2387 bremfree(nbp); 2388 bawrite(nbp); 2389 } 2390 dirtybufferflushes++; 2391 break; 2392 } 2393 if (nbp == NULL) 2394 BO_UNLOCK(bo); 2395 } 2396 } 2397 2398 /* 2399 * Delayed write. (Buffer is marked dirty). Do not bother writing 2400 * anything if the buffer is marked invalid. 2401 * 2402 * Note that since the buffer must be completely valid, we can safely 2403 * set B_CACHE. In fact, we have to set B_CACHE here rather then in 2404 * biodone() in order to prevent getblk from writing the buffer 2405 * out synchronously. 2406 */ 2407 void 2408 bdwrite(struct buf *bp) 2409 { 2410 struct thread *td = curthread; 2411 struct vnode *vp; 2412 struct bufobj *bo; 2413 2414 CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2415 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2416 KASSERT((bp->b_flags & B_BARRIER) == 0, 2417 ("Barrier request in delayed write %p", bp)); 2418 2419 if (bp->b_flags & B_INVAL) { 2420 brelse(bp); 2421 return; 2422 } 2423 2424 /* 2425 * If we have too many dirty buffers, don't create any more. 2426 * If we are wildly over our limit, then force a complete 2427 * cleanup. Otherwise, just keep the situation from getting 2428 * out of control. Note that we have to avoid a recursive 2429 * disaster and not try to clean up after our own cleanup! 2430 */ 2431 vp = bp->b_vp; 2432 bo = bp->b_bufobj; 2433 if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) { 2434 td->td_pflags |= TDP_INBDFLUSH; 2435 BO_BDFLUSH(bo, bp); 2436 td->td_pflags &= ~TDP_INBDFLUSH; 2437 } else 2438 recursiveflushes++; 2439 2440 bdirty(bp); 2441 /* 2442 * Set B_CACHE, indicating that the buffer is fully valid. This is 2443 * true even of NFS now. 2444 */ 2445 bp->b_flags |= B_CACHE; 2446 2447 /* 2448 * This bmap keeps the system from needing to do the bmap later, 2449 * perhaps when the system is attempting to do a sync. Since it 2450 * is likely that the indirect block -- or whatever other datastructure 2451 * that the filesystem needs is still in memory now, it is a good 2452 * thing to do this. Note also, that if the pageout daemon is 2453 * requesting a sync -- there might not be enough memory to do 2454 * the bmap then... So, this is important to do. 2455 */ 2456 if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) { 2457 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 2458 } 2459 2460 buf_track(bp, __func__); 2461 2462 /* 2463 * Set the *dirty* buffer range based upon the VM system dirty 2464 * pages. 2465 * 2466 * Mark the buffer pages as clean. We need to do this here to 2467 * satisfy the vnode_pager and the pageout daemon, so that it 2468 * thinks that the pages have been "cleaned". Note that since 2469 * the pages are in a delayed write buffer -- the VFS layer 2470 * "will" see that the pages get written out on the next sync, 2471 * or perhaps the cluster will be completed. 2472 */ 2473 vfs_clean_pages_dirty_buf(bp); 2474 bqrelse(bp); 2475 2476 /* 2477 * note: we cannot initiate I/O from a bdwrite even if we wanted to, 2478 * due to the softdep code. 2479 */ 2480 } 2481 2482 /* 2483 * bdirty: 2484 * 2485 * Turn buffer into delayed write request. We must clear BIO_READ and 2486 * B_RELBUF, and we must set B_DELWRI. We reassign the buffer to 2487 * itself to properly update it in the dirty/clean lists. We mark it 2488 * B_DONE to ensure that any asynchronization of the buffer properly 2489 * clears B_DONE ( else a panic will occur later ). 2490 * 2491 * bdirty() is kinda like bdwrite() - we have to clear B_INVAL which 2492 * might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty() 2493 * should only be called if the buffer is known-good. 2494 * 2495 * Since the buffer is not on a queue, we do not update the numfreebuffers 2496 * count. 2497 * 2498 * The buffer must be on QUEUE_NONE. 2499 */ 2500 void 2501 bdirty(struct buf *bp) 2502 { 2503 2504 CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X", 2505 bp, bp->b_vp, bp->b_flags); 2506 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2507 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2508 ("bdirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2509 bp->b_flags &= ~(B_RELBUF); 2510 bp->b_iocmd = BIO_WRITE; 2511 2512 if ((bp->b_flags & B_DELWRI) == 0) { 2513 bp->b_flags |= /* XXX B_DONE | */ B_DELWRI; 2514 reassignbuf(bp); 2515 bdirtyadd(bp); 2516 } 2517 } 2518 2519 /* 2520 * bundirty: 2521 * 2522 * Clear B_DELWRI for buffer. 2523 * 2524 * Since the buffer is not on a queue, we do not update the numfreebuffers 2525 * count. 2526 * 2527 * The buffer must be on QUEUE_NONE. 2528 */ 2529 2530 void 2531 bundirty(struct buf *bp) 2532 { 2533 2534 CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2535 KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp)); 2536 KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE, 2537 ("bundirty: buffer %p still on queue %d", bp, bp->b_qindex)); 2538 2539 if (bp->b_flags & B_DELWRI) { 2540 bp->b_flags &= ~B_DELWRI; 2541 reassignbuf(bp); 2542 bdirtysub(bp); 2543 } 2544 /* 2545 * Since it is now being written, we can clear its deferred write flag. 2546 */ 2547 bp->b_flags &= ~B_DEFERRED; 2548 } 2549 2550 /* 2551 * bawrite: 2552 * 2553 * Asynchronous write. Start output on a buffer, but do not wait for 2554 * it to complete. The buffer is released when the output completes. 2555 * 2556 * bwrite() ( or the VOP routine anyway ) is responsible for handling 2557 * B_INVAL buffers. Not us. 2558 */ 2559 void 2560 bawrite(struct buf *bp) 2561 { 2562 2563 bp->b_flags |= B_ASYNC; 2564 (void) bwrite(bp); 2565 } 2566 2567 /* 2568 * babarrierwrite: 2569 * 2570 * Asynchronous barrier write. Start output on a buffer, but do not 2571 * wait for it to complete. Place a write barrier after this write so 2572 * that this buffer and all buffers written before it are committed to 2573 * the disk before any buffers written after this write are committed 2574 * to the disk. The buffer is released when the output completes. 2575 */ 2576 void 2577 babarrierwrite(struct buf *bp) 2578 { 2579 2580 bp->b_flags |= B_ASYNC | B_BARRIER; 2581 (void) bwrite(bp); 2582 } 2583 2584 /* 2585 * bbarrierwrite: 2586 * 2587 * Synchronous barrier write. Start output on a buffer and wait for 2588 * it to complete. Place a write barrier after this write so that 2589 * this buffer and all buffers written before it are committed to 2590 * the disk before any buffers written after this write are committed 2591 * to the disk. The buffer is released when the output completes. 2592 */ 2593 int 2594 bbarrierwrite(struct buf *bp) 2595 { 2596 2597 bp->b_flags |= B_BARRIER; 2598 return (bwrite(bp)); 2599 } 2600 2601 /* 2602 * bwillwrite: 2603 * 2604 * Called prior to the locking of any vnodes when we are expecting to 2605 * write. We do not want to starve the buffer cache with too many 2606 * dirty buffers so we block here. By blocking prior to the locking 2607 * of any vnodes we attempt to avoid the situation where a locked vnode 2608 * prevents the various system daemons from flushing related buffers. 2609 */ 2610 void 2611 bwillwrite(void) 2612 { 2613 2614 if (buf_dirty_count_severe()) { 2615 mtx_lock(&bdirtylock); 2616 while (buf_dirty_count_severe()) { 2617 bdirtywait = 1; 2618 msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4), 2619 "flswai", 0); 2620 } 2621 mtx_unlock(&bdirtylock); 2622 } 2623 } 2624 2625 /* 2626 * Return true if we have too many dirty buffers. 2627 */ 2628 int 2629 buf_dirty_count_severe(void) 2630 { 2631 2632 return (!BIT_EMPTY(BUF_DOMAINS, &bdhidirty)); 2633 } 2634 2635 /* 2636 * brelse: 2637 * 2638 * Release a busy buffer and, if requested, free its resources. The 2639 * buffer will be stashed in the appropriate bufqueue[] allowing it 2640 * to be accessed later as a cache entity or reused for other purposes. 2641 */ 2642 void 2643 brelse(struct buf *bp) 2644 { 2645 struct mount *v_mnt; 2646 int qindex; 2647 2648 /* 2649 * Many functions erroneously call brelse with a NULL bp under rare 2650 * error conditions. Simply return when called with a NULL bp. 2651 */ 2652 if (bp == NULL) 2653 return; 2654 CTR3(KTR_BUF, "brelse(%p) vp %p flags %X", 2655 bp, bp->b_vp, bp->b_flags); 2656 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2657 ("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2658 KASSERT((bp->b_flags & B_VMIO) != 0 || (bp->b_flags & B_NOREUSE) == 0, 2659 ("brelse: non-VMIO buffer marked NOREUSE")); 2660 2661 if (BUF_LOCKRECURSED(bp)) { 2662 /* 2663 * Do not process, in particular, do not handle the 2664 * B_INVAL/B_RELBUF and do not release to free list. 2665 */ 2666 BUF_UNLOCK(bp); 2667 return; 2668 } 2669 2670 if (bp->b_flags & B_MANAGED) { 2671 bqrelse(bp); 2672 return; 2673 } 2674 2675 if (LIST_EMPTY(&bp->b_dep)) { 2676 bp->b_flags &= ~B_IOSTARTED; 2677 } else { 2678 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2679 ("brelse: SU io not finished bp %p", bp)); 2680 } 2681 2682 if ((bp->b_vflags & (BV_BKGRDINPROG | BV_BKGRDERR)) == BV_BKGRDERR) { 2683 BO_LOCK(bp->b_bufobj); 2684 bp->b_vflags &= ~BV_BKGRDERR; 2685 BO_UNLOCK(bp->b_bufobj); 2686 bdirty(bp); 2687 } 2688 2689 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2690 (bp->b_flags & B_INVALONERR)) { 2691 /* 2692 * Forced invalidation of dirty buffer contents, to be used 2693 * after a failed write in the rare case that the loss of the 2694 * contents is acceptable. The buffer is invalidated and 2695 * freed. 2696 */ 2697 bp->b_flags |= B_INVAL | B_RELBUF | B_NOCACHE; 2698 bp->b_flags &= ~(B_ASYNC | B_CACHE); 2699 } 2700 2701 if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) && 2702 (bp->b_error != ENXIO || !LIST_EMPTY(&bp->b_dep)) && 2703 !(bp->b_flags & B_INVAL)) { 2704 /* 2705 * Failed write, redirty. All errors except ENXIO (which 2706 * means the device is gone) are treated as being 2707 * transient. 2708 * 2709 * XXX Treating EIO as transient is not correct; the 2710 * contract with the local storage device drivers is that 2711 * they will only return EIO once the I/O is no longer 2712 * retriable. Network I/O also respects this through the 2713 * guarantees of TCP and/or the internal retries of NFS. 2714 * ENOMEM might be transient, but we also have no way of 2715 * knowing when its ok to retry/reschedule. In general, 2716 * this entire case should be made obsolete through better 2717 * error handling/recovery and resource scheduling. 2718 * 2719 * Do this also for buffers that failed with ENXIO, but have 2720 * non-empty dependencies - the soft updates code might need 2721 * to access the buffer to untangle them. 2722 * 2723 * Must clear BIO_ERROR to prevent pages from being scrapped. 2724 */ 2725 bp->b_ioflags &= ~BIO_ERROR; 2726 bdirty(bp); 2727 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) || 2728 (bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) { 2729 /* 2730 * Either a failed read I/O, or we were asked to free or not 2731 * cache the buffer, or we failed to write to a device that's 2732 * no longer present. 2733 */ 2734 bp->b_flags |= B_INVAL; 2735 if (!LIST_EMPTY(&bp->b_dep)) 2736 buf_deallocate(bp); 2737 if (bp->b_flags & B_DELWRI) 2738 bdirtysub(bp); 2739 bp->b_flags &= ~(B_DELWRI | B_CACHE); 2740 if ((bp->b_flags & B_VMIO) == 0) { 2741 allocbuf(bp, 0); 2742 if (bp->b_vp) 2743 brelvp(bp); 2744 } 2745 } 2746 2747 /* 2748 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_truncate() 2749 * is called with B_DELWRI set, the underlying pages may wind up 2750 * getting freed causing a previous write (bdwrite()) to get 'lost' 2751 * because pages associated with a B_DELWRI bp are marked clean. 2752 * 2753 * We still allow the B_INVAL case to call vfs_vmio_truncate(), even 2754 * if B_DELWRI is set. 2755 */ 2756 if (bp->b_flags & B_DELWRI) 2757 bp->b_flags &= ~B_RELBUF; 2758 2759 /* 2760 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 2761 * constituted, not even NFS buffers now. Two flags effect this. If 2762 * B_INVAL, the struct buf is invalidated but the VM object is kept 2763 * around ( i.e. so it is trivial to reconstitute the buffer later ). 2764 * 2765 * If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be 2766 * invalidated. BIO_ERROR cannot be set for a failed write unless the 2767 * buffer is also B_INVAL because it hits the re-dirtying code above. 2768 * 2769 * Normally we can do this whether a buffer is B_DELWRI or not. If 2770 * the buffer is an NFS buffer, it is tracking piecemeal writes or 2771 * the commit state and we cannot afford to lose the buffer. If the 2772 * buffer has a background write in progress, we need to keep it 2773 * around to prevent it from being reconstituted and starting a second 2774 * background write. 2775 */ 2776 2777 v_mnt = bp->b_vp != NULL ? bp->b_vp->v_mount : NULL; 2778 2779 if ((bp->b_flags & B_VMIO) && (bp->b_flags & B_NOCACHE || 2780 (bp->b_ioflags & BIO_ERROR && bp->b_iocmd == BIO_READ)) && 2781 (v_mnt == NULL || (v_mnt->mnt_vfc->vfc_flags & VFCF_NETWORK) == 0 || 2782 vn_isdisk(bp->b_vp) || (bp->b_flags & B_DELWRI) == 0)) { 2783 vfs_vmio_invalidate(bp); 2784 allocbuf(bp, 0); 2785 } 2786 2787 if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0 || 2788 (bp->b_flags & (B_DELWRI | B_NOREUSE)) == B_NOREUSE) { 2789 allocbuf(bp, 0); 2790 bp->b_flags &= ~B_NOREUSE; 2791 if (bp->b_vp != NULL) 2792 brelvp(bp); 2793 } 2794 2795 /* 2796 * If the buffer has junk contents signal it and eventually 2797 * clean up B_DELWRI and diassociate the vnode so that gbincore() 2798 * doesn't find it. 2799 */ 2800 if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 || 2801 (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0) 2802 bp->b_flags |= B_INVAL; 2803 if (bp->b_flags & B_INVAL) { 2804 if (bp->b_flags & B_DELWRI) 2805 bundirty(bp); 2806 if (bp->b_vp) 2807 brelvp(bp); 2808 } 2809 2810 buf_track(bp, __func__); 2811 2812 /* buffers with no memory */ 2813 if (bp->b_bufsize == 0) { 2814 buf_free(bp); 2815 return; 2816 } 2817 /* buffers with junk contents */ 2818 if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) || 2819 (bp->b_ioflags & BIO_ERROR)) { 2820 bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA); 2821 if (bp->b_vflags & BV_BKGRDINPROG) 2822 panic("losing buffer 2"); 2823 qindex = QUEUE_CLEAN; 2824 bp->b_flags |= B_AGE; 2825 /* remaining buffers */ 2826 } else if (bp->b_flags & B_DELWRI) 2827 qindex = QUEUE_DIRTY; 2828 else 2829 qindex = QUEUE_CLEAN; 2830 2831 if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY)) 2832 panic("brelse: not dirty"); 2833 2834 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_RELBUF | B_DIRECT); 2835 bp->b_xflags &= ~(BX_CVTENXIO); 2836 /* binsfree unlocks bp. */ 2837 binsfree(bp, qindex); 2838 } 2839 2840 /* 2841 * Release a buffer back to the appropriate queue but do not try to free 2842 * it. The buffer is expected to be used again soon. 2843 * 2844 * bqrelse() is used by bdwrite() to requeue a delayed write, and used by 2845 * biodone() to requeue an async I/O on completion. It is also used when 2846 * known good buffers need to be requeued but we think we may need the data 2847 * again soon. 2848 * 2849 * XXX we should be able to leave the B_RELBUF hint set on completion. 2850 */ 2851 void 2852 bqrelse(struct buf *bp) 2853 { 2854 int qindex; 2855 2856 CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 2857 KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)), 2858 ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp)); 2859 2860 qindex = QUEUE_NONE; 2861 if (BUF_LOCKRECURSED(bp)) { 2862 /* do not release to free list */ 2863 BUF_UNLOCK(bp); 2864 return; 2865 } 2866 bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 2867 bp->b_xflags &= ~(BX_CVTENXIO); 2868 2869 if (LIST_EMPTY(&bp->b_dep)) { 2870 bp->b_flags &= ~B_IOSTARTED; 2871 } else { 2872 KASSERT((bp->b_flags & B_IOSTARTED) == 0, 2873 ("bqrelse: SU io not finished bp %p", bp)); 2874 } 2875 2876 if (bp->b_flags & B_MANAGED) { 2877 if (bp->b_flags & B_REMFREE) 2878 bremfreef(bp); 2879 goto out; 2880 } 2881 2882 /* buffers with stale but valid contents */ 2883 if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG | 2884 BV_BKGRDERR)) == BV_BKGRDERR) { 2885 BO_LOCK(bp->b_bufobj); 2886 bp->b_vflags &= ~BV_BKGRDERR; 2887 BO_UNLOCK(bp->b_bufobj); 2888 qindex = QUEUE_DIRTY; 2889 } else { 2890 if ((bp->b_flags & B_DELWRI) == 0 && 2891 (bp->b_xflags & BX_VNDIRTY)) 2892 panic("bqrelse: not dirty"); 2893 if ((bp->b_flags & B_NOREUSE) != 0) { 2894 brelse(bp); 2895 return; 2896 } 2897 qindex = QUEUE_CLEAN; 2898 } 2899 buf_track(bp, __func__); 2900 /* binsfree unlocks bp. */ 2901 binsfree(bp, qindex); 2902 return; 2903 2904 out: 2905 buf_track(bp, __func__); 2906 /* unlock */ 2907 BUF_UNLOCK(bp); 2908 } 2909 2910 /* 2911 * Complete I/O to a VMIO backed page. Validate the pages as appropriate, 2912 * restore bogus pages. 2913 */ 2914 static void 2915 vfs_vmio_iodone(struct buf *bp) 2916 { 2917 vm_ooffset_t foff; 2918 vm_page_t m; 2919 vm_object_t obj; 2920 struct vnode *vp __unused; 2921 int i, iosize, resid; 2922 bool bogus; 2923 2924 obj = bp->b_bufobj->bo_object; 2925 KASSERT(blockcount_read(&obj->paging_in_progress) >= bp->b_npages, 2926 ("vfs_vmio_iodone: paging in progress(%d) < b_npages(%d)", 2927 blockcount_read(&obj->paging_in_progress), bp->b_npages)); 2928 2929 vp = bp->b_vp; 2930 VNPASS(vp->v_holdcnt > 0, vp); 2931 VNPASS(vp->v_object != NULL, vp); 2932 2933 foff = bp->b_offset; 2934 KASSERT(bp->b_offset != NOOFFSET, 2935 ("vfs_vmio_iodone: bp %p has no buffer offset", bp)); 2936 2937 bogus = false; 2938 iosize = bp->b_bcount - bp->b_resid; 2939 for (i = 0; i < bp->b_npages; i++) { 2940 resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff; 2941 if (resid > iosize) 2942 resid = iosize; 2943 2944 /* 2945 * cleanup bogus pages, restoring the originals 2946 */ 2947 m = bp->b_pages[i]; 2948 if (m == bogus_page) { 2949 bogus = true; 2950 m = vm_page_relookup(obj, OFF_TO_IDX(foff)); 2951 if (m == NULL) 2952 panic("biodone: page disappeared!"); 2953 bp->b_pages[i] = m; 2954 } else if ((bp->b_iocmd == BIO_READ) && resid > 0) { 2955 /* 2956 * In the write case, the valid and clean bits are 2957 * already changed correctly ( see bdwrite() ), so we 2958 * only need to do this here in the read case. 2959 */ 2960 KASSERT((m->dirty & vm_page_bits(foff & PAGE_MASK, 2961 resid)) == 0, ("vfs_vmio_iodone: page %p " 2962 "has unexpected dirty bits", m)); 2963 vfs_page_set_valid(bp, foff, m); 2964 } 2965 KASSERT(OFF_TO_IDX(foff) == m->pindex, 2966 ("vfs_vmio_iodone: foff(%jd)/pindex(%ju) mismatch", 2967 (intmax_t)foff, (uintmax_t)m->pindex)); 2968 2969 vm_page_sunbusy(m); 2970 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 2971 iosize -= resid; 2972 } 2973 vm_object_pip_wakeupn(obj, bp->b_npages); 2974 if (bogus && buf_mapped(bp)) { 2975 BUF_CHECK_MAPPED(bp); 2976 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 2977 bp->b_pages, bp->b_npages); 2978 } 2979 } 2980 2981 /* 2982 * Perform page invalidation when a buffer is released. The fully invalid 2983 * pages will be reclaimed later in vfs_vmio_truncate(). 2984 */ 2985 static void 2986 vfs_vmio_invalidate(struct buf *bp) 2987 { 2988 vm_object_t obj; 2989 vm_page_t m; 2990 int flags, i, resid, poffset, presid; 2991 2992 if (buf_mapped(bp)) { 2993 BUF_CHECK_MAPPED(bp); 2994 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages); 2995 } else 2996 BUF_CHECK_UNMAPPED(bp); 2997 /* 2998 * Get the base offset and length of the buffer. Note that 2999 * in the VMIO case if the buffer block size is not 3000 * page-aligned then b_data pointer may not be page-aligned. 3001 * But our b_pages[] array *IS* page aligned. 3002 * 3003 * block sizes less then DEV_BSIZE (usually 512) are not 3004 * supported due to the page granularity bits (m->valid, 3005 * m->dirty, etc...). 3006 * 3007 * See man buf(9) for more information 3008 */ 3009 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3010 obj = bp->b_bufobj->bo_object; 3011 resid = bp->b_bufsize; 3012 poffset = bp->b_offset & PAGE_MASK; 3013 VM_OBJECT_WLOCK(obj); 3014 for (i = 0; i < bp->b_npages; i++) { 3015 m = bp->b_pages[i]; 3016 if (m == bogus_page) 3017 panic("vfs_vmio_invalidate: Unexpected bogus page."); 3018 bp->b_pages[i] = NULL; 3019 3020 presid = resid > (PAGE_SIZE - poffset) ? 3021 (PAGE_SIZE - poffset) : resid; 3022 KASSERT(presid >= 0, ("brelse: extra page")); 3023 vm_page_busy_acquire(m, VM_ALLOC_SBUSY); 3024 if (pmap_page_wired_mappings(m) == 0) 3025 vm_page_set_invalid(m, poffset, presid); 3026 vm_page_sunbusy(m); 3027 vm_page_release_locked(m, flags); 3028 resid -= presid; 3029 poffset = 0; 3030 } 3031 VM_OBJECT_WUNLOCK(obj); 3032 bp->b_npages = 0; 3033 } 3034 3035 /* 3036 * Page-granular truncation of an existing VMIO buffer. 3037 */ 3038 static void 3039 vfs_vmio_truncate(struct buf *bp, int desiredpages) 3040 { 3041 vm_object_t obj; 3042 vm_page_t m; 3043 int flags, i; 3044 3045 if (bp->b_npages == desiredpages) 3046 return; 3047 3048 if (buf_mapped(bp)) { 3049 BUF_CHECK_MAPPED(bp); 3050 pmap_qremove((vm_offset_t)trunc_page((vm_offset_t)bp->b_data) + 3051 (desiredpages << PAGE_SHIFT), bp->b_npages - desiredpages); 3052 } else 3053 BUF_CHECK_UNMAPPED(bp); 3054 3055 /* 3056 * The object lock is needed only if we will attempt to free pages. 3057 */ 3058 flags = (bp->b_flags & B_NOREUSE) != 0 ? VPR_NOREUSE : 0; 3059 if ((bp->b_flags & B_DIRECT) != 0) { 3060 flags |= VPR_TRYFREE; 3061 obj = bp->b_bufobj->bo_object; 3062 VM_OBJECT_WLOCK(obj); 3063 } else { 3064 obj = NULL; 3065 } 3066 for (i = desiredpages; i < bp->b_npages; i++) { 3067 m = bp->b_pages[i]; 3068 KASSERT(m != bogus_page, ("allocbuf: bogus page found")); 3069 bp->b_pages[i] = NULL; 3070 if (obj != NULL) 3071 vm_page_release_locked(m, flags); 3072 else 3073 vm_page_release(m, flags); 3074 } 3075 if (obj != NULL) 3076 VM_OBJECT_WUNLOCK(obj); 3077 bp->b_npages = desiredpages; 3078 } 3079 3080 /* 3081 * Byte granular extension of VMIO buffers. 3082 */ 3083 static void 3084 vfs_vmio_extend(struct buf *bp, int desiredpages, int size) 3085 { 3086 /* 3087 * We are growing the buffer, possibly in a 3088 * byte-granular fashion. 3089 */ 3090 vm_object_t obj; 3091 vm_offset_t toff; 3092 vm_offset_t tinc; 3093 vm_page_t m; 3094 3095 /* 3096 * Step 1, bring in the VM pages from the object, allocating 3097 * them if necessary. We must clear B_CACHE if these pages 3098 * are not valid for the range covered by the buffer. 3099 */ 3100 obj = bp->b_bufobj->bo_object; 3101 if (bp->b_npages < desiredpages) { 3102 KASSERT(desiredpages <= atop(maxbcachebuf), 3103 ("vfs_vmio_extend past maxbcachebuf %p %d %u", 3104 bp, desiredpages, maxbcachebuf)); 3105 3106 /* 3107 * We must allocate system pages since blocking 3108 * here could interfere with paging I/O, no 3109 * matter which process we are. 3110 * 3111 * Only exclusive busy can be tested here. 3112 * Blocking on shared busy might lead to 3113 * deadlocks once allocbuf() is called after 3114 * pages are vfs_busy_pages(). 3115 */ 3116 (void)vm_page_grab_pages_unlocked(obj, 3117 OFF_TO_IDX(bp->b_offset) + bp->b_npages, 3118 VM_ALLOC_SYSTEM | VM_ALLOC_IGN_SBUSY | 3119 VM_ALLOC_NOBUSY | VM_ALLOC_WIRED, 3120 &bp->b_pages[bp->b_npages], desiredpages - bp->b_npages); 3121 bp->b_npages = desiredpages; 3122 } 3123 3124 /* 3125 * Step 2. We've loaded the pages into the buffer, 3126 * we have to figure out if we can still have B_CACHE 3127 * set. Note that B_CACHE is set according to the 3128 * byte-granular range ( bcount and size ), not the 3129 * aligned range ( newbsize ). 3130 * 3131 * The VM test is against m->valid, which is DEV_BSIZE 3132 * aligned. Needless to say, the validity of the data 3133 * needs to also be DEV_BSIZE aligned. Note that this 3134 * fails with NFS if the server or some other client 3135 * extends the file's EOF. If our buffer is resized, 3136 * B_CACHE may remain set! XXX 3137 */ 3138 toff = bp->b_bcount; 3139 tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK); 3140 while ((bp->b_flags & B_CACHE) && toff < size) { 3141 vm_pindex_t pi; 3142 3143 if (tinc > (size - toff)) 3144 tinc = size - toff; 3145 pi = ((bp->b_offset & PAGE_MASK) + toff) >> PAGE_SHIFT; 3146 m = bp->b_pages[pi]; 3147 vfs_buf_test_cache(bp, bp->b_offset, toff, tinc, m); 3148 toff += tinc; 3149 tinc = PAGE_SIZE; 3150 } 3151 3152 /* 3153 * Step 3, fixup the KVA pmap. 3154 */ 3155 if (buf_mapped(bp)) 3156 bpmap_qenter(bp); 3157 else 3158 BUF_CHECK_UNMAPPED(bp); 3159 } 3160 3161 /* 3162 * Check to see if a block at a particular lbn is available for a clustered 3163 * write. 3164 */ 3165 static int 3166 vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno) 3167 { 3168 struct buf *bpa; 3169 int match; 3170 3171 match = 0; 3172 3173 /* If the buf isn't in core skip it */ 3174 if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL) 3175 return (0); 3176 3177 /* If the buf is busy we don't want to wait for it */ 3178 if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) 3179 return (0); 3180 3181 /* Only cluster with valid clusterable delayed write buffers */ 3182 if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) != 3183 (B_DELWRI | B_CLUSTEROK)) 3184 goto done; 3185 3186 if (bpa->b_bufsize != size) 3187 goto done; 3188 3189 /* 3190 * Check to see if it is in the expected place on disk and that the 3191 * block has been mapped. 3192 */ 3193 if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno)) 3194 match = 1; 3195 done: 3196 BUF_UNLOCK(bpa); 3197 return (match); 3198 } 3199 3200 /* 3201 * vfs_bio_awrite: 3202 * 3203 * Implement clustered async writes for clearing out B_DELWRI buffers. 3204 * This is much better then the old way of writing only one buffer at 3205 * a time. Note that we may not be presented with the buffers in the 3206 * correct order, so we search for the cluster in both directions. 3207 */ 3208 int 3209 vfs_bio_awrite(struct buf *bp) 3210 { 3211 struct bufobj *bo; 3212 int i; 3213 int j; 3214 daddr_t lblkno = bp->b_lblkno; 3215 struct vnode *vp = bp->b_vp; 3216 int ncl; 3217 int nwritten; 3218 int size; 3219 int maxcl; 3220 int gbflags; 3221 3222 bo = &vp->v_bufobj; 3223 gbflags = (bp->b_data == unmapped_buf) ? GB_UNMAPPED : 0; 3224 /* 3225 * right now we support clustered writing only to regular files. If 3226 * we find a clusterable block we could be in the middle of a cluster 3227 * rather then at the beginning. 3228 */ 3229 if ((vp->v_type == VREG) && 3230 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 3231 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 3232 size = vp->v_mount->mnt_stat.f_iosize; 3233 maxcl = maxphys / size; 3234 3235 BO_RLOCK(bo); 3236 for (i = 1; i < maxcl; i++) 3237 if (vfs_bio_clcheck(vp, size, lblkno + i, 3238 bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0) 3239 break; 3240 3241 for (j = 1; i + j <= maxcl && j <= lblkno; j++) 3242 if (vfs_bio_clcheck(vp, size, lblkno - j, 3243 bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0) 3244 break; 3245 BO_RUNLOCK(bo); 3246 --j; 3247 ncl = i + j; 3248 /* 3249 * this is a possible cluster write 3250 */ 3251 if (ncl != 1) { 3252 BUF_UNLOCK(bp); 3253 nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, 3254 gbflags); 3255 return (nwritten); 3256 } 3257 } 3258 bremfree(bp); 3259 bp->b_flags |= B_ASYNC; 3260 /* 3261 * default (old) behavior, writing out only one block 3262 * 3263 * XXX returns b_bufsize instead of b_bcount for nwritten? 3264 */ 3265 nwritten = bp->b_bufsize; 3266 (void) bwrite(bp); 3267 3268 return (nwritten); 3269 } 3270 3271 /* 3272 * getnewbuf_kva: 3273 * 3274 * Allocate KVA for an empty buf header according to gbflags. 3275 */ 3276 static int 3277 getnewbuf_kva(struct buf *bp, int gbflags, int maxsize) 3278 { 3279 3280 if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_UNMAPPED) { 3281 /* 3282 * In order to keep fragmentation sane we only allocate kva 3283 * in BKVASIZE chunks. XXX with vmem we can do page size. 3284 */ 3285 maxsize = (maxsize + BKVAMASK) & ~BKVAMASK; 3286 3287 if (maxsize != bp->b_kvasize && 3288 bufkva_alloc(bp, maxsize, gbflags)) 3289 return (ENOSPC); 3290 } 3291 return (0); 3292 } 3293 3294 /* 3295 * getnewbuf: 3296 * 3297 * Find and initialize a new buffer header, freeing up existing buffers 3298 * in the bufqueues as necessary. The new buffer is returned locked. 3299 * 3300 * We block if: 3301 * We have insufficient buffer headers 3302 * We have insufficient buffer space 3303 * buffer_arena is too fragmented ( space reservation fails ) 3304 * If we have to flush dirty buffers ( but we try to avoid this ) 3305 * 3306 * The caller is responsible for releasing the reserved bufspace after 3307 * allocbuf() is called. 3308 */ 3309 static struct buf * 3310 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int maxsize, int gbflags) 3311 { 3312 struct bufdomain *bd; 3313 struct buf *bp; 3314 bool metadata, reserved; 3315 3316 bp = NULL; 3317 KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3318 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3319 if (!unmapped_buf_allowed) 3320 gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3321 3322 if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 || 3323 vp->v_type == VCHR) 3324 metadata = true; 3325 else 3326 metadata = false; 3327 if (vp == NULL) 3328 bd = &bdomain[0]; 3329 else 3330 bd = &bdomain[vp->v_bufobj.bo_domain]; 3331 3332 counter_u64_add(getnewbufcalls, 1); 3333 reserved = false; 3334 do { 3335 if (reserved == false && 3336 bufspace_reserve(bd, maxsize, metadata) != 0) { 3337 counter_u64_add(getnewbufrestarts, 1); 3338 continue; 3339 } 3340 reserved = true; 3341 if ((bp = buf_alloc(bd)) == NULL) { 3342 counter_u64_add(getnewbufrestarts, 1); 3343 continue; 3344 } 3345 if (getnewbuf_kva(bp, gbflags, maxsize) == 0) 3346 return (bp); 3347 break; 3348 } while (buf_recycle(bd, false) == 0); 3349 3350 if (reserved) 3351 bufspace_release(bd, maxsize); 3352 if (bp != NULL) { 3353 bp->b_flags |= B_INVAL; 3354 brelse(bp); 3355 } 3356 bufspace_wait(bd, vp, gbflags, slpflag, slptimeo); 3357 3358 return (NULL); 3359 } 3360 3361 /* 3362 * buf_daemon: 3363 * 3364 * buffer flushing daemon. Buffers are normally flushed by the 3365 * update daemon but if it cannot keep up this process starts to 3366 * take the load in an attempt to prevent getnewbuf() from blocking. 3367 */ 3368 static struct kproc_desc buf_kp = { 3369 "bufdaemon", 3370 buf_daemon, 3371 &bufdaemonproc 3372 }; 3373 SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp); 3374 3375 static int 3376 buf_flush(struct vnode *vp, struct bufdomain *bd, int target) 3377 { 3378 int flushed; 3379 3380 flushed = flushbufqueues(vp, bd, target, 0); 3381 if (flushed == 0) { 3382 /* 3383 * Could not find any buffers without rollback 3384 * dependencies, so just write the first one 3385 * in the hopes of eventually making progress. 3386 */ 3387 if (vp != NULL && target > 2) 3388 target /= 2; 3389 flushbufqueues(vp, bd, target, 1); 3390 } 3391 return (flushed); 3392 } 3393 3394 static void 3395 buf_daemon() 3396 { 3397 struct bufdomain *bd; 3398 int speedupreq; 3399 int lodirty; 3400 int i; 3401 3402 /* 3403 * This process needs to be suspended prior to shutdown sync. 3404 */ 3405 EVENTHANDLER_REGISTER(shutdown_pre_sync, kthread_shutdown, curthread, 3406 SHUTDOWN_PRI_LAST + 100); 3407 3408 /* 3409 * Start the buf clean daemons as children threads. 3410 */ 3411 for (i = 0 ; i < buf_domains; i++) { 3412 int error; 3413 3414 error = kthread_add((void (*)(void *))bufspace_daemon, 3415 &bdomain[i], curproc, NULL, 0, 0, "bufspacedaemon-%d", i); 3416 if (error) 3417 panic("error %d spawning bufspace daemon", error); 3418 } 3419 3420 /* 3421 * This process is allowed to take the buffer cache to the limit 3422 */ 3423 curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED; 3424 mtx_lock(&bdlock); 3425 for (;;) { 3426 bd_request = 0; 3427 mtx_unlock(&bdlock); 3428 3429 kthread_suspend_check(); 3430 3431 /* 3432 * Save speedupreq for this pass and reset to capture new 3433 * requests. 3434 */ 3435 speedupreq = bd_speedupreq; 3436 bd_speedupreq = 0; 3437 3438 /* 3439 * Flush each domain sequentially according to its level and 3440 * the speedup request. 3441 */ 3442 for (i = 0; i < buf_domains; i++) { 3443 bd = &bdomain[i]; 3444 if (speedupreq) 3445 lodirty = bd->bd_numdirtybuffers / 2; 3446 else 3447 lodirty = bd->bd_lodirtybuffers; 3448 while (bd->bd_numdirtybuffers > lodirty) { 3449 if (buf_flush(NULL, bd, 3450 bd->bd_numdirtybuffers - lodirty) == 0) 3451 break; 3452 kern_yield(PRI_USER); 3453 } 3454 } 3455 3456 /* 3457 * Only clear bd_request if we have reached our low water 3458 * mark. The buf_daemon normally waits 1 second and 3459 * then incrementally flushes any dirty buffers that have 3460 * built up, within reason. 3461 * 3462 * If we were unable to hit our low water mark and couldn't 3463 * find any flushable buffers, we sleep for a short period 3464 * to avoid endless loops on unlockable buffers. 3465 */ 3466 mtx_lock(&bdlock); 3467 if (!BIT_EMPTY(BUF_DOMAINS, &bdlodirty)) { 3468 /* 3469 * We reached our low water mark, reset the 3470 * request and sleep until we are needed again. 3471 * The sleep is just so the suspend code works. 3472 */ 3473 bd_request = 0; 3474 /* 3475 * Do an extra wakeup in case dirty threshold 3476 * changed via sysctl and the explicit transition 3477 * out of shortfall was missed. 3478 */ 3479 bdirtywakeup(); 3480 if (runningbufspace <= lorunningspace) 3481 runningwakeup(); 3482 msleep(&bd_request, &bdlock, PVM, "psleep", hz); 3483 } else { 3484 /* 3485 * We couldn't find any flushable dirty buffers but 3486 * still have too many dirty buffers, we 3487 * have to sleep and try again. (rare) 3488 */ 3489 msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10); 3490 } 3491 } 3492 } 3493 3494 /* 3495 * flushbufqueues: 3496 * 3497 * Try to flush a buffer in the dirty queue. We must be careful to 3498 * free up B_INVAL buffers instead of write them, which NFS is 3499 * particularly sensitive to. 3500 */ 3501 static int flushwithdeps = 0; 3502 SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW | CTLFLAG_STATS, 3503 &flushwithdeps, 0, 3504 "Number of buffers flushed with dependencies that require rollbacks"); 3505 3506 static int 3507 flushbufqueues(struct vnode *lvp, struct bufdomain *bd, int target, 3508 int flushdeps) 3509 { 3510 struct bufqueue *bq; 3511 struct buf *sentinel; 3512 struct vnode *vp; 3513 struct mount *mp; 3514 struct buf *bp; 3515 int hasdeps; 3516 int flushed; 3517 int error; 3518 bool unlock; 3519 3520 flushed = 0; 3521 bq = &bd->bd_dirtyq; 3522 bp = NULL; 3523 sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO); 3524 sentinel->b_qindex = QUEUE_SENTINEL; 3525 BQ_LOCK(bq); 3526 TAILQ_INSERT_HEAD(&bq->bq_queue, sentinel, b_freelist); 3527 BQ_UNLOCK(bq); 3528 while (flushed != target) { 3529 maybe_yield(); 3530 BQ_LOCK(bq); 3531 bp = TAILQ_NEXT(sentinel, b_freelist); 3532 if (bp != NULL) { 3533 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3534 TAILQ_INSERT_AFTER(&bq->bq_queue, bp, sentinel, 3535 b_freelist); 3536 } else { 3537 BQ_UNLOCK(bq); 3538 break; 3539 } 3540 /* 3541 * Skip sentinels inserted by other invocations of the 3542 * flushbufqueues(), taking care to not reorder them. 3543 * 3544 * Only flush the buffers that belong to the 3545 * vnode locked by the curthread. 3546 */ 3547 if (bp->b_qindex == QUEUE_SENTINEL || (lvp != NULL && 3548 bp->b_vp != lvp)) { 3549 BQ_UNLOCK(bq); 3550 continue; 3551 } 3552 error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL); 3553 BQ_UNLOCK(bq); 3554 if (error != 0) 3555 continue; 3556 3557 /* 3558 * BKGRDINPROG can only be set with the buf and bufobj 3559 * locks both held. We tolerate a race to clear it here. 3560 */ 3561 if ((bp->b_vflags & BV_BKGRDINPROG) != 0 || 3562 (bp->b_flags & B_DELWRI) == 0) { 3563 BUF_UNLOCK(bp); 3564 continue; 3565 } 3566 if (bp->b_flags & B_INVAL) { 3567 bremfreef(bp); 3568 brelse(bp); 3569 flushed++; 3570 continue; 3571 } 3572 3573 if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) { 3574 if (flushdeps == 0) { 3575 BUF_UNLOCK(bp); 3576 continue; 3577 } 3578 hasdeps = 1; 3579 } else 3580 hasdeps = 0; 3581 /* 3582 * We must hold the lock on a vnode before writing 3583 * one of its buffers. Otherwise we may confuse, or 3584 * in the case of a snapshot vnode, deadlock the 3585 * system. 3586 * 3587 * The lock order here is the reverse of the normal 3588 * of vnode followed by buf lock. This is ok because 3589 * the NOWAIT will prevent deadlock. 3590 */ 3591 vp = bp->b_vp; 3592 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { 3593 BUF_UNLOCK(bp); 3594 continue; 3595 } 3596 if (lvp == NULL) { 3597 unlock = true; 3598 error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT); 3599 } else { 3600 ASSERT_VOP_LOCKED(vp, "getbuf"); 3601 unlock = false; 3602 error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 : 3603 vn_lock(vp, LK_TRYUPGRADE); 3604 } 3605 if (error == 0) { 3606 CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X", 3607 bp, bp->b_vp, bp->b_flags); 3608 if (curproc == bufdaemonproc) { 3609 vfs_bio_awrite(bp); 3610 } else { 3611 bremfree(bp); 3612 bwrite(bp); 3613 counter_u64_add(notbufdflushes, 1); 3614 } 3615 vn_finished_write(mp); 3616 if (unlock) 3617 VOP_UNLOCK(vp); 3618 flushwithdeps += hasdeps; 3619 flushed++; 3620 3621 /* 3622 * Sleeping on runningbufspace while holding 3623 * vnode lock leads to deadlock. 3624 */ 3625 if (curproc == bufdaemonproc && 3626 runningbufspace > hirunningspace) 3627 waitrunningbufspace(); 3628 continue; 3629 } 3630 vn_finished_write(mp); 3631 BUF_UNLOCK(bp); 3632 } 3633 BQ_LOCK(bq); 3634 TAILQ_REMOVE(&bq->bq_queue, sentinel, b_freelist); 3635 BQ_UNLOCK(bq); 3636 free(sentinel, M_TEMP); 3637 return (flushed); 3638 } 3639 3640 /* 3641 * Check to see if a block is currently memory resident. 3642 */ 3643 struct buf * 3644 incore(struct bufobj *bo, daddr_t blkno) 3645 { 3646 return (gbincore_unlocked(bo, blkno)); 3647 } 3648 3649 /* 3650 * Returns true if no I/O is needed to access the 3651 * associated VM object. This is like incore except 3652 * it also hunts around in the VM system for the data. 3653 */ 3654 bool 3655 inmem(struct vnode * vp, daddr_t blkno) 3656 { 3657 vm_object_t obj; 3658 vm_offset_t toff, tinc, size; 3659 vm_page_t m, n; 3660 vm_ooffset_t off; 3661 int valid; 3662 3663 ASSERT_VOP_LOCKED(vp, "inmem"); 3664 3665 if (incore(&vp->v_bufobj, blkno)) 3666 return (true); 3667 if (vp->v_mount == NULL) 3668 return (false); 3669 obj = vp->v_object; 3670 if (obj == NULL) 3671 return (false); 3672 3673 size = PAGE_SIZE; 3674 if (size > vp->v_mount->mnt_stat.f_iosize) 3675 size = vp->v_mount->mnt_stat.f_iosize; 3676 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 3677 3678 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 3679 m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3680 recheck: 3681 if (m == NULL) 3682 return (false); 3683 3684 tinc = size; 3685 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 3686 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 3687 /* 3688 * Consider page validity only if page mapping didn't change 3689 * during the check. 3690 */ 3691 valid = vm_page_is_valid(m, 3692 (vm_offset_t)((toff + off) & PAGE_MASK), tinc); 3693 n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); 3694 if (m != n) { 3695 m = n; 3696 goto recheck; 3697 } 3698 if (!valid) 3699 return (false); 3700 } 3701 return (true); 3702 } 3703 3704 /* 3705 * Set the dirty range for a buffer based on the status of the dirty 3706 * bits in the pages comprising the buffer. The range is limited 3707 * to the size of the buffer. 3708 * 3709 * Tell the VM system that the pages associated with this buffer 3710 * are clean. This is used for delayed writes where the data is 3711 * going to go to disk eventually without additional VM intevention. 3712 * 3713 * Note that while we only really need to clean through to b_bcount, we 3714 * just go ahead and clean through to b_bufsize. 3715 */ 3716 static void 3717 vfs_clean_pages_dirty_buf(struct buf *bp) 3718 { 3719 vm_ooffset_t foff, noff, eoff; 3720 vm_page_t m; 3721 int i; 3722 3723 if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0) 3724 return; 3725 3726 foff = bp->b_offset; 3727 KASSERT(bp->b_offset != NOOFFSET, 3728 ("vfs_clean_pages_dirty_buf: no buffer offset")); 3729 3730 vfs_busy_pages_acquire(bp); 3731 vfs_setdirty_range(bp); 3732 for (i = 0; i < bp->b_npages; i++) { 3733 noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 3734 eoff = noff; 3735 if (eoff > bp->b_offset + bp->b_bufsize) 3736 eoff = bp->b_offset + bp->b_bufsize; 3737 m = bp->b_pages[i]; 3738 vfs_page_set_validclean(bp, foff, m); 3739 /* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */ 3740 foff = noff; 3741 } 3742 vfs_busy_pages_release(bp); 3743 } 3744 3745 static void 3746 vfs_setdirty_range(struct buf *bp) 3747 { 3748 vm_offset_t boffset; 3749 vm_offset_t eoffset; 3750 int i; 3751 3752 /* 3753 * test the pages to see if they have been modified directly 3754 * by users through the VM system. 3755 */ 3756 for (i = 0; i < bp->b_npages; i++) 3757 vm_page_test_dirty(bp->b_pages[i]); 3758 3759 /* 3760 * Calculate the encompassing dirty range, boffset and eoffset, 3761 * (eoffset - boffset) bytes. 3762 */ 3763 3764 for (i = 0; i < bp->b_npages; i++) { 3765 if (bp->b_pages[i]->dirty) 3766 break; 3767 } 3768 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3769 3770 for (i = bp->b_npages - 1; i >= 0; --i) { 3771 if (bp->b_pages[i]->dirty) { 3772 break; 3773 } 3774 } 3775 eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 3776 3777 /* 3778 * Fit it to the buffer. 3779 */ 3780 3781 if (eoffset > bp->b_bcount) 3782 eoffset = bp->b_bcount; 3783 3784 /* 3785 * If we have a good dirty range, merge with the existing 3786 * dirty range. 3787 */ 3788 3789 if (boffset < eoffset) { 3790 if (bp->b_dirtyoff > boffset) 3791 bp->b_dirtyoff = boffset; 3792 if (bp->b_dirtyend < eoffset) 3793 bp->b_dirtyend = eoffset; 3794 } 3795 } 3796 3797 /* 3798 * Allocate the KVA mapping for an existing buffer. 3799 * If an unmapped buffer is provided but a mapped buffer is requested, take 3800 * also care to properly setup mappings between pages and KVA. 3801 */ 3802 static void 3803 bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags) 3804 { 3805 int bsize, maxsize, need_mapping, need_kva; 3806 off_t offset; 3807 3808 need_mapping = bp->b_data == unmapped_buf && 3809 (gbflags & GB_UNMAPPED) == 0; 3810 need_kva = bp->b_kvabase == unmapped_buf && 3811 bp->b_data == unmapped_buf && 3812 (gbflags & GB_KVAALLOC) != 0; 3813 if (!need_mapping && !need_kva) 3814 return; 3815 3816 BUF_CHECK_UNMAPPED(bp); 3817 3818 if (need_mapping && bp->b_kvabase != unmapped_buf) { 3819 /* 3820 * Buffer is not mapped, but the KVA was already 3821 * reserved at the time of the instantiation. Use the 3822 * allocated space. 3823 */ 3824 goto has_addr; 3825 } 3826 3827 /* 3828 * Calculate the amount of the address space we would reserve 3829 * if the buffer was mapped. 3830 */ 3831 bsize = vn_isdisk(bp->b_vp) ? DEV_BSIZE : bp->b_bufobj->bo_bsize; 3832 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 3833 offset = blkno * bsize; 3834 maxsize = size + (offset & PAGE_MASK); 3835 maxsize = imax(maxsize, bsize); 3836 3837 while (bufkva_alloc(bp, maxsize, gbflags) != 0) { 3838 if ((gbflags & GB_NOWAIT_BD) != 0) { 3839 /* 3840 * XXXKIB: defragmentation cannot 3841 * succeed, not sure what else to do. 3842 */ 3843 panic("GB_NOWAIT_BD and GB_UNMAPPED %p", bp); 3844 } 3845 counter_u64_add(mappingrestarts, 1); 3846 bufspace_wait(bufdomain(bp), bp->b_vp, gbflags, 0, 0); 3847 } 3848 has_addr: 3849 if (need_mapping) { 3850 /* b_offset is handled by bpmap_qenter. */ 3851 bp->b_data = bp->b_kvabase; 3852 BUF_CHECK_MAPPED(bp); 3853 bpmap_qenter(bp); 3854 } 3855 } 3856 3857 struct buf * 3858 getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo, 3859 int flags) 3860 { 3861 struct buf *bp; 3862 int error; 3863 3864 error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp); 3865 if (error != 0) 3866 return (NULL); 3867 return (bp); 3868 } 3869 3870 /* 3871 * getblkx: 3872 * 3873 * Get a block given a specified block and offset into a file/device. 3874 * The buffers B_DONE bit will be cleared on return, making it almost 3875 * ready for an I/O initiation. B_INVAL may or may not be set on 3876 * return. The caller should clear B_INVAL prior to initiating a 3877 * READ. 3878 * 3879 * For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for 3880 * an existing buffer. 3881 * 3882 * For a VMIO buffer, B_CACHE is modified according to the backing VM. 3883 * If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set 3884 * and then cleared based on the backing VM. If the previous buffer is 3885 * non-0-sized but invalid, B_CACHE will be cleared. 3886 * 3887 * If getblk() must create a new buffer, the new buffer is returned with 3888 * both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which 3889 * case it is returned with B_INVAL clear and B_CACHE set based on the 3890 * backing VM. 3891 * 3892 * getblk() also forces a bwrite() for any B_DELWRI buffer whose 3893 * B_CACHE bit is clear. 3894 * 3895 * What this means, basically, is that the caller should use B_CACHE to 3896 * determine whether the buffer is fully valid or not and should clear 3897 * B_INVAL prior to issuing a read. If the caller intends to validate 3898 * the buffer by loading its data area with something, the caller needs 3899 * to clear B_INVAL. If the caller does this without issuing an I/O, 3900 * the caller should set B_CACHE ( as an optimization ), else the caller 3901 * should issue the I/O and biodone() will set B_CACHE if the I/O was 3902 * a write attempt or if it was a successful read. If the caller 3903 * intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR 3904 * prior to issuing the READ. biodone() will *not* clear B_INVAL. 3905 * 3906 * The blkno parameter is the logical block being requested. Normally 3907 * the mapping of logical block number to disk block address is done 3908 * by calling VOP_BMAP(). However, if the mapping is already known, the 3909 * disk block address can be passed using the dblkno parameter. If the 3910 * disk block address is not known, then the same value should be passed 3911 * for blkno and dblkno. 3912 */ 3913 int 3914 getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag, 3915 int slptimeo, int flags, struct buf **bpp) 3916 { 3917 struct buf *bp; 3918 struct bufobj *bo; 3919 daddr_t d_blkno; 3920 int bsize, error, maxsize, vmio; 3921 off_t offset; 3922 3923 CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size); 3924 KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC, 3925 ("GB_KVAALLOC only makes sense with GB_UNMAPPED")); 3926 if (vp->v_type != VCHR) 3927 ASSERT_VOP_LOCKED(vp, "getblk"); 3928 if (size > maxbcachebuf) 3929 panic("getblk: size(%d) > maxbcachebuf(%d)\n", size, 3930 maxbcachebuf); 3931 if (!unmapped_buf_allowed) 3932 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 3933 3934 bo = &vp->v_bufobj; 3935 d_blkno = dblkno; 3936 3937 /* Attempt lockless lookup first. */ 3938 bp = gbincore_unlocked(bo, blkno); 3939 if (bp == NULL) { 3940 /* 3941 * With GB_NOCREAT we must be sure about not finding the buffer 3942 * as it may have been reassigned during unlocked lookup. 3943 */ 3944 if ((flags & GB_NOCREAT) != 0) 3945 goto loop; 3946 goto newbuf_unlocked; 3947 } 3948 3949 error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL, "getblku", 0, 3950 0); 3951 if (error != 0) 3952 goto loop; 3953 3954 /* Verify buf identify has not changed since lookup. */ 3955 if (bp->b_bufobj == bo && bp->b_lblkno == blkno) 3956 goto foundbuf_fastpath; 3957 3958 /* It changed, fallback to locked lookup. */ 3959 BUF_UNLOCK_RAW(bp); 3960 3961 loop: 3962 BO_RLOCK(bo); 3963 bp = gbincore(bo, blkno); 3964 if (bp != NULL) { 3965 int lockflags; 3966 3967 /* 3968 * Buffer is in-core. If the buffer is not busy nor managed, 3969 * it must be on a queue. 3970 */ 3971 lockflags = LK_EXCLUSIVE | LK_INTERLOCK | 3972 ((flags & GB_LOCK_NOWAIT) ? LK_NOWAIT : LK_SLEEPFAIL); 3973 3974 error = BUF_TIMELOCK(bp, lockflags, 3975 BO_LOCKPTR(bo), "getblk", slpflag, slptimeo); 3976 3977 /* 3978 * If we slept and got the lock we have to restart in case 3979 * the buffer changed identities. 3980 */ 3981 if (error == ENOLCK) 3982 goto loop; 3983 /* We timed out or were interrupted. */ 3984 else if (error != 0) 3985 return (error); 3986 3987 foundbuf_fastpath: 3988 /* If recursed, assume caller knows the rules. */ 3989 if (BUF_LOCKRECURSED(bp)) 3990 goto end; 3991 3992 /* 3993 * The buffer is locked. B_CACHE is cleared if the buffer is 3994 * invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set 3995 * and for a VMIO buffer B_CACHE is adjusted according to the 3996 * backing VM cache. 3997 */ 3998 if (bp->b_flags & B_INVAL) 3999 bp->b_flags &= ~B_CACHE; 4000 else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0) 4001 bp->b_flags |= B_CACHE; 4002 if (bp->b_flags & B_MANAGED) 4003 MPASS(bp->b_qindex == QUEUE_NONE); 4004 else 4005 bremfree(bp); 4006 4007 /* 4008 * check for size inconsistencies for non-VMIO case. 4009 */ 4010 if (bp->b_bcount != size) { 4011 if ((bp->b_flags & B_VMIO) == 0 || 4012 (size > bp->b_kvasize)) { 4013 if (bp->b_flags & B_DELWRI) { 4014 bp->b_flags |= B_NOCACHE; 4015 bwrite(bp); 4016 } else { 4017 if (LIST_EMPTY(&bp->b_dep)) { 4018 bp->b_flags |= B_RELBUF; 4019 brelse(bp); 4020 } else { 4021 bp->b_flags |= B_NOCACHE; 4022 bwrite(bp); 4023 } 4024 } 4025 goto loop; 4026 } 4027 } 4028 4029 /* 4030 * Handle the case of unmapped buffer which should 4031 * become mapped, or the buffer for which KVA 4032 * reservation is requested. 4033 */ 4034 bp_unmapped_get_kva(bp, blkno, size, flags); 4035 4036 /* 4037 * If the size is inconsistent in the VMIO case, we can resize 4038 * the buffer. This might lead to B_CACHE getting set or 4039 * cleared. If the size has not changed, B_CACHE remains 4040 * unchanged from its previous state. 4041 */ 4042 allocbuf(bp, size); 4043 4044 KASSERT(bp->b_offset != NOOFFSET, 4045 ("getblk: no buffer offset")); 4046 4047 /* 4048 * A buffer with B_DELWRI set and B_CACHE clear must 4049 * be committed before we can return the buffer in 4050 * order to prevent the caller from issuing a read 4051 * ( due to B_CACHE not being set ) and overwriting 4052 * it. 4053 * 4054 * Most callers, including NFS and FFS, need this to 4055 * operate properly either because they assume they 4056 * can issue a read if B_CACHE is not set, or because 4057 * ( for example ) an uncached B_DELWRI might loop due 4058 * to softupdates re-dirtying the buffer. In the latter 4059 * case, B_CACHE is set after the first write completes, 4060 * preventing further loops. 4061 * NOTE! b*write() sets B_CACHE. If we cleared B_CACHE 4062 * above while extending the buffer, we cannot allow the 4063 * buffer to remain with B_CACHE set after the write 4064 * completes or it will represent a corrupt state. To 4065 * deal with this we set B_NOCACHE to scrap the buffer 4066 * after the write. 4067 * 4068 * We might be able to do something fancy, like setting 4069 * B_CACHE in bwrite() except if B_DELWRI is already set, 4070 * so the below call doesn't set B_CACHE, but that gets real 4071 * confusing. This is much easier. 4072 */ 4073 4074 if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) { 4075 bp->b_flags |= B_NOCACHE; 4076 bwrite(bp); 4077 goto loop; 4078 } 4079 bp->b_flags &= ~B_DONE; 4080 } else { 4081 /* 4082 * Buffer is not in-core, create new buffer. The buffer 4083 * returned by getnewbuf() is locked. Note that the returned 4084 * buffer is also considered valid (not marked B_INVAL). 4085 */ 4086 BO_RUNLOCK(bo); 4087 newbuf_unlocked: 4088 /* 4089 * If the user does not want us to create the buffer, bail out 4090 * here. 4091 */ 4092 if (flags & GB_NOCREAT) 4093 return (EEXIST); 4094 4095 bsize = vn_isdisk(vp) ? DEV_BSIZE : bo->bo_bsize; 4096 KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize")); 4097 offset = blkno * bsize; 4098 vmio = vp->v_object != NULL; 4099 if (vmio) { 4100 maxsize = size + (offset & PAGE_MASK); 4101 } else { 4102 maxsize = size; 4103 /* Do not allow non-VMIO notmapped buffers. */ 4104 flags &= ~(GB_UNMAPPED | GB_KVAALLOC); 4105 } 4106 maxsize = imax(maxsize, bsize); 4107 if ((flags & GB_NOSPARSE) != 0 && vmio && 4108 !vn_isdisk(vp)) { 4109 error = VOP_BMAP(vp, blkno, NULL, &d_blkno, 0, 0); 4110 KASSERT(error != EOPNOTSUPP, 4111 ("GB_NOSPARSE from fs not supporting bmap, vp %p", 4112 vp)); 4113 if (error != 0) 4114 return (error); 4115 if (d_blkno == -1) 4116 return (EJUSTRETURN); 4117 } 4118 4119 bp = getnewbuf(vp, slpflag, slptimeo, maxsize, flags); 4120 if (bp == NULL) { 4121 if (slpflag || slptimeo) 4122 return (ETIMEDOUT); 4123 /* 4124 * XXX This is here until the sleep path is diagnosed 4125 * enough to work under very low memory conditions. 4126 * 4127 * There's an issue on low memory, 4BSD+non-preempt 4128 * systems (eg MIPS routers with 32MB RAM) where buffer 4129 * exhaustion occurs without sleeping for buffer 4130 * reclaimation. This just sticks in a loop and 4131 * constantly attempts to allocate a buffer, which 4132 * hits exhaustion and tries to wakeup bufdaemon. 4133 * This never happens because we never yield. 4134 * 4135 * The real solution is to identify and fix these cases 4136 * so we aren't effectively busy-waiting in a loop 4137 * until the reclaimation path has cycles to run. 4138 */ 4139 kern_yield(PRI_USER); 4140 goto loop; 4141 } 4142 4143 /* 4144 * This code is used to make sure that a buffer is not 4145 * created while the getnewbuf routine is blocked. 4146 * This can be a problem whether the vnode is locked or not. 4147 * If the buffer is created out from under us, we have to 4148 * throw away the one we just created. 4149 * 4150 * Note: this must occur before we associate the buffer 4151 * with the vp especially considering limitations in 4152 * the splay tree implementation when dealing with duplicate 4153 * lblkno's. 4154 */ 4155 BO_LOCK(bo); 4156 if (gbincore(bo, blkno)) { 4157 BO_UNLOCK(bo); 4158 bp->b_flags |= B_INVAL; 4159 bufspace_release(bufdomain(bp), maxsize); 4160 brelse(bp); 4161 goto loop; 4162 } 4163 4164 /* 4165 * Insert the buffer into the hash, so that it can 4166 * be found by incore. 4167 */ 4168 bp->b_lblkno = blkno; 4169 bp->b_blkno = d_blkno; 4170 bp->b_offset = offset; 4171 bgetvp(vp, bp); 4172 BO_UNLOCK(bo); 4173 4174 /* 4175 * set B_VMIO bit. allocbuf() the buffer bigger. Since the 4176 * buffer size starts out as 0, B_CACHE will be set by 4177 * allocbuf() for the VMIO case prior to it testing the 4178 * backing store for validity. 4179 */ 4180 4181 if (vmio) { 4182 bp->b_flags |= B_VMIO; 4183 KASSERT(vp->v_object == bp->b_bufobj->bo_object, 4184 ("ARGH! different b_bufobj->bo_object %p %p %p\n", 4185 bp, vp->v_object, bp->b_bufobj->bo_object)); 4186 } else { 4187 bp->b_flags &= ~B_VMIO; 4188 KASSERT(bp->b_bufobj->bo_object == NULL, 4189 ("ARGH! has b_bufobj->bo_object %p %p\n", 4190 bp, bp->b_bufobj->bo_object)); 4191 BUF_CHECK_MAPPED(bp); 4192 } 4193 4194 allocbuf(bp, size); 4195 bufspace_release(bufdomain(bp), maxsize); 4196 bp->b_flags &= ~B_DONE; 4197 } 4198 CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp); 4199 end: 4200 buf_track(bp, __func__); 4201 KASSERT(bp->b_bufobj == bo, 4202 ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo)); 4203 *bpp = bp; 4204 return (0); 4205 } 4206 4207 /* 4208 * Get an empty, disassociated buffer of given size. The buffer is initially 4209 * set to B_INVAL. 4210 */ 4211 struct buf * 4212 geteblk(int size, int flags) 4213 { 4214 struct buf *bp; 4215 int maxsize; 4216 4217 maxsize = (size + BKVAMASK) & ~BKVAMASK; 4218 while ((bp = getnewbuf(NULL, 0, 0, maxsize, flags)) == NULL) { 4219 if ((flags & GB_NOWAIT_BD) && 4220 (curthread->td_pflags & TDP_BUFNEED) != 0) 4221 return (NULL); 4222 } 4223 allocbuf(bp, size); 4224 bufspace_release(bufdomain(bp), maxsize); 4225 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 4226 return (bp); 4227 } 4228 4229 /* 4230 * Truncate the backing store for a non-vmio buffer. 4231 */ 4232 static void 4233 vfs_nonvmio_truncate(struct buf *bp, int newbsize) 4234 { 4235 4236 if (bp->b_flags & B_MALLOC) { 4237 /* 4238 * malloced buffers are not shrunk 4239 */ 4240 if (newbsize == 0) { 4241 bufmallocadjust(bp, 0); 4242 free(bp->b_data, M_BIOBUF); 4243 bp->b_data = bp->b_kvabase; 4244 bp->b_flags &= ~B_MALLOC; 4245 } 4246 return; 4247 } 4248 vm_hold_free_pages(bp, newbsize); 4249 bufspace_adjust(bp, newbsize); 4250 } 4251 4252 /* 4253 * Extend the backing for a non-VMIO buffer. 4254 */ 4255 static void 4256 vfs_nonvmio_extend(struct buf *bp, int newbsize) 4257 { 4258 caddr_t origbuf; 4259 int origbufsize; 4260 4261 /* 4262 * We only use malloced memory on the first allocation. 4263 * and revert to page-allocated memory when the buffer 4264 * grows. 4265 * 4266 * There is a potential smp race here that could lead 4267 * to bufmallocspace slightly passing the max. It 4268 * is probably extremely rare and not worth worrying 4269 * over. 4270 */ 4271 if (bp->b_bufsize == 0 && newbsize <= PAGE_SIZE/2 && 4272 bufmallocspace < maxbufmallocspace) { 4273 bp->b_data = malloc(newbsize, M_BIOBUF, M_WAITOK); 4274 bp->b_flags |= B_MALLOC; 4275 bufmallocadjust(bp, newbsize); 4276 return; 4277 } 4278 4279 /* 4280 * If the buffer is growing on its other-than-first 4281 * allocation then we revert to the page-allocation 4282 * scheme. 4283 */ 4284 origbuf = NULL; 4285 origbufsize = 0; 4286 if (bp->b_flags & B_MALLOC) { 4287 origbuf = bp->b_data; 4288 origbufsize = bp->b_bufsize; 4289 bp->b_data = bp->b_kvabase; 4290 bufmallocadjust(bp, 0); 4291 bp->b_flags &= ~B_MALLOC; 4292 newbsize = round_page(newbsize); 4293 } 4294 vm_hold_load_pages(bp, (vm_offset_t) bp->b_data + bp->b_bufsize, 4295 (vm_offset_t) bp->b_data + newbsize); 4296 if (origbuf != NULL) { 4297 bcopy(origbuf, bp->b_data, origbufsize); 4298 free(origbuf, M_BIOBUF); 4299 } 4300 bufspace_adjust(bp, newbsize); 4301 } 4302 4303 /* 4304 * This code constitutes the buffer memory from either anonymous system 4305 * memory (in the case of non-VMIO operations) or from an associated 4306 * VM object (in the case of VMIO operations). This code is able to 4307 * resize a buffer up or down. 4308 * 4309 * Note that this code is tricky, and has many complications to resolve 4310 * deadlock or inconsistent data situations. Tread lightly!!! 4311 * There are B_CACHE and B_DELWRI interactions that must be dealt with by 4312 * the caller. Calling this code willy nilly can result in the loss of data. 4313 * 4314 * allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with 4315 * B_CACHE for the non-VMIO case. 4316 */ 4317 int 4318 allocbuf(struct buf *bp, int size) 4319 { 4320 int newbsize; 4321 4322 if (bp->b_bcount == size) 4323 return (1); 4324 4325 if (bp->b_kvasize != 0 && bp->b_kvasize < size) 4326 panic("allocbuf: buffer too small"); 4327 4328 newbsize = roundup2(size, DEV_BSIZE); 4329 if ((bp->b_flags & B_VMIO) == 0) { 4330 if ((bp->b_flags & B_MALLOC) == 0) 4331 newbsize = round_page(newbsize); 4332 /* 4333 * Just get anonymous memory from the kernel. Don't 4334 * mess with B_CACHE. 4335 */ 4336 if (newbsize < bp->b_bufsize) 4337 vfs_nonvmio_truncate(bp, newbsize); 4338 else if (newbsize > bp->b_bufsize) 4339 vfs_nonvmio_extend(bp, newbsize); 4340 } else { 4341 int desiredpages; 4342 4343 desiredpages = (size == 0) ? 0 : 4344 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 4345 4346 if (bp->b_flags & B_MALLOC) 4347 panic("allocbuf: VMIO buffer can't be malloced"); 4348 /* 4349 * Set B_CACHE initially if buffer is 0 length or will become 4350 * 0-length. 4351 */ 4352 if (size == 0 || bp->b_bufsize == 0) 4353 bp->b_flags |= B_CACHE; 4354 4355 if (newbsize < bp->b_bufsize) 4356 vfs_vmio_truncate(bp, desiredpages); 4357 /* XXX This looks as if it should be newbsize > b_bufsize */ 4358 else if (size > bp->b_bcount) 4359 vfs_vmio_extend(bp, desiredpages, size); 4360 bufspace_adjust(bp, newbsize); 4361 } 4362 bp->b_bcount = size; /* requested buffer size. */ 4363 return (1); 4364 } 4365 4366 extern int inflight_transient_maps; 4367 4368 static struct bio_queue nondump_bios; 4369 4370 void 4371 biodone(struct bio *bp) 4372 { 4373 struct mtx *mtxp; 4374 void (*done)(struct bio *); 4375 vm_offset_t start, end; 4376 4377 biotrack(bp, __func__); 4378 4379 /* 4380 * Avoid completing I/O when dumping after a panic since that may 4381 * result in a deadlock in the filesystem or pager code. Note that 4382 * this doesn't affect dumps that were started manually since we aim 4383 * to keep the system usable after it has been resumed. 4384 */ 4385 if (__predict_false(dumping && SCHEDULER_STOPPED())) { 4386 TAILQ_INSERT_HEAD(&nondump_bios, bp, bio_queue); 4387 return; 4388 } 4389 if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { 4390 bp->bio_flags &= ~BIO_TRANSIENT_MAPPING; 4391 bp->bio_flags |= BIO_UNMAPPED; 4392 start = trunc_page((vm_offset_t)bp->bio_data); 4393 end = round_page((vm_offset_t)bp->bio_data + bp->bio_length); 4394 bp->bio_data = unmapped_buf; 4395 pmap_qremove(start, atop(end - start)); 4396 vmem_free(transient_arena, start, end - start); 4397 atomic_add_int(&inflight_transient_maps, -1); 4398 } 4399 done = bp->bio_done; 4400 /* 4401 * The check for done == biodone is to allow biodone to be 4402 * used as a bio_done routine. 4403 */ 4404 if (done == NULL || done == biodone) { 4405 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4406 mtx_lock(mtxp); 4407 bp->bio_flags |= BIO_DONE; 4408 wakeup(bp); 4409 mtx_unlock(mtxp); 4410 } else 4411 done(bp); 4412 } 4413 4414 /* 4415 * Wait for a BIO to finish. 4416 */ 4417 int 4418 biowait(struct bio *bp, const char *wmesg) 4419 { 4420 struct mtx *mtxp; 4421 4422 mtxp = mtx_pool_find(mtxpool_sleep, bp); 4423 mtx_lock(mtxp); 4424 while ((bp->bio_flags & BIO_DONE) == 0) 4425 msleep(bp, mtxp, PRIBIO, wmesg, 0); 4426 mtx_unlock(mtxp); 4427 if (bp->bio_error != 0) 4428 return (bp->bio_error); 4429 if (!(bp->bio_flags & BIO_ERROR)) 4430 return (0); 4431 return (EIO); 4432 } 4433 4434 void 4435 biofinish(struct bio *bp, struct devstat *stat, int error) 4436 { 4437 4438 if (error) { 4439 bp->bio_error = error; 4440 bp->bio_flags |= BIO_ERROR; 4441 } 4442 if (stat != NULL) 4443 devstat_end_transaction_bio(stat, bp); 4444 biodone(bp); 4445 } 4446 4447 #if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING) 4448 void 4449 biotrack_buf(struct bio *bp, const char *location) 4450 { 4451 4452 buf_track(bp->bio_track_bp, location); 4453 } 4454 #endif 4455 4456 /* 4457 * bufwait: 4458 * 4459 * Wait for buffer I/O completion, returning error status. The buffer 4460 * is left locked and B_DONE on return. B_EINTR is converted into an EINTR 4461 * error and cleared. 4462 */ 4463 int 4464 bufwait(struct buf *bp) 4465 { 4466 if (bp->b_iocmd == BIO_READ) 4467 bwait(bp, PRIBIO, "biord"); 4468 else 4469 bwait(bp, PRIBIO, "biowr"); 4470 if (bp->b_flags & B_EINTR) { 4471 bp->b_flags &= ~B_EINTR; 4472 return (EINTR); 4473 } 4474 if (bp->b_ioflags & BIO_ERROR) { 4475 return (bp->b_error ? bp->b_error : EIO); 4476 } else { 4477 return (0); 4478 } 4479 } 4480 4481 /* 4482 * bufdone: 4483 * 4484 * Finish I/O on a buffer, optionally calling a completion function. 4485 * This is usually called from an interrupt so process blocking is 4486 * not allowed. 4487 * 4488 * biodone is also responsible for setting B_CACHE in a B_VMIO bp. 4489 * In a non-VMIO bp, B_CACHE will be set on the next getblk() 4490 * assuming B_INVAL is clear. 4491 * 4492 * For the VMIO case, we set B_CACHE if the op was a read and no 4493 * read error occurred, or if the op was a write. B_CACHE is never 4494 * set if the buffer is invalid or otherwise uncacheable. 4495 * 4496 * bufdone does not mess with B_INVAL, allowing the I/O routine or the 4497 * initiator to leave B_INVAL set to brelse the buffer out of existence 4498 * in the biodone routine. 4499 */ 4500 void 4501 bufdone(struct buf *bp) 4502 { 4503 struct bufobj *dropobj; 4504 void (*biodone)(struct buf *); 4505 4506 buf_track(bp, __func__); 4507 CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags); 4508 dropobj = NULL; 4509 4510 KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp)); 4511 4512 runningbufwakeup(bp); 4513 if (bp->b_iocmd == BIO_WRITE) 4514 dropobj = bp->b_bufobj; 4515 /* call optional completion function if requested */ 4516 if (bp->b_iodone != NULL) { 4517 biodone = bp->b_iodone; 4518 bp->b_iodone = NULL; 4519 (*biodone) (bp); 4520 if (dropobj) 4521 bufobj_wdrop(dropobj); 4522 return; 4523 } 4524 if (bp->b_flags & B_VMIO) { 4525 /* 4526 * Set B_CACHE if the op was a normal read and no error 4527 * occurred. B_CACHE is set for writes in the b*write() 4528 * routines. 4529 */ 4530 if (bp->b_iocmd == BIO_READ && 4531 !(bp->b_flags & (B_INVAL|B_NOCACHE)) && 4532 !(bp->b_ioflags & BIO_ERROR)) 4533 bp->b_flags |= B_CACHE; 4534 vfs_vmio_iodone(bp); 4535 } 4536 if (!LIST_EMPTY(&bp->b_dep)) 4537 buf_complete(bp); 4538 if ((bp->b_flags & B_CKHASH) != 0) { 4539 KASSERT(bp->b_iocmd == BIO_READ, 4540 ("bufdone: b_iocmd %d not BIO_READ", bp->b_iocmd)); 4541 KASSERT(buf_mapped(bp), ("bufdone: bp %p not mapped", bp)); 4542 (*bp->b_ckhashcalc)(bp); 4543 } 4544 /* 4545 * For asynchronous completions, release the buffer now. The brelse 4546 * will do a wakeup there if necessary - so no need to do a wakeup 4547 * here in the async case. The sync case always needs to do a wakeup. 4548 */ 4549 if (bp->b_flags & B_ASYNC) { 4550 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) || 4551 (bp->b_ioflags & BIO_ERROR)) 4552 brelse(bp); 4553 else 4554 bqrelse(bp); 4555 } else 4556 bdone(bp); 4557 if (dropobj) 4558 bufobj_wdrop(dropobj); 4559 } 4560 4561 /* 4562 * This routine is called in lieu of iodone in the case of 4563 * incomplete I/O. This keeps the busy status for pages 4564 * consistent. 4565 */ 4566 void 4567 vfs_unbusy_pages(struct buf *bp) 4568 { 4569 int i; 4570 vm_object_t obj; 4571 vm_page_t m; 4572 4573 runningbufwakeup(bp); 4574 if (!(bp->b_flags & B_VMIO)) 4575 return; 4576 4577 obj = bp->b_bufobj->bo_object; 4578 for (i = 0; i < bp->b_npages; i++) { 4579 m = bp->b_pages[i]; 4580 if (m == bogus_page) { 4581 m = vm_page_relookup(obj, OFF_TO_IDX(bp->b_offset) + i); 4582 if (!m) 4583 panic("vfs_unbusy_pages: page missing\n"); 4584 bp->b_pages[i] = m; 4585 if (buf_mapped(bp)) { 4586 BUF_CHECK_MAPPED(bp); 4587 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4588 bp->b_pages, bp->b_npages); 4589 } else 4590 BUF_CHECK_UNMAPPED(bp); 4591 } 4592 vm_page_sunbusy(m); 4593 } 4594 vm_object_pip_wakeupn(obj, bp->b_npages); 4595 } 4596 4597 /* 4598 * vfs_page_set_valid: 4599 * 4600 * Set the valid bits in a page based on the supplied offset. The 4601 * range is restricted to the buffer's size. 4602 * 4603 * This routine is typically called after a read completes. 4604 */ 4605 static void 4606 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4607 { 4608 vm_ooffset_t eoff; 4609 4610 /* 4611 * Compute the end offset, eoff, such that [off, eoff) does not span a 4612 * page boundary and eoff is not greater than the end of the buffer. 4613 * The end of the buffer, in this case, is our file EOF, not the 4614 * allocation size of the buffer. 4615 */ 4616 eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK; 4617 if (eoff > bp->b_offset + bp->b_bcount) 4618 eoff = bp->b_offset + bp->b_bcount; 4619 4620 /* 4621 * Set valid range. This is typically the entire buffer and thus the 4622 * entire page. 4623 */ 4624 if (eoff > off) 4625 vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off); 4626 } 4627 4628 /* 4629 * vfs_page_set_validclean: 4630 * 4631 * Set the valid bits and clear the dirty bits in a page based on the 4632 * supplied offset. The range is restricted to the buffer's size. 4633 */ 4634 static void 4635 vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m) 4636 { 4637 vm_ooffset_t soff, eoff; 4638 4639 /* 4640 * Start and end offsets in buffer. eoff - soff may not cross a 4641 * page boundary or cross the end of the buffer. The end of the 4642 * buffer, in this case, is our file EOF, not the allocation size 4643 * of the buffer. 4644 */ 4645 soff = off; 4646 eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4647 if (eoff > bp->b_offset + bp->b_bcount) 4648 eoff = bp->b_offset + bp->b_bcount; 4649 4650 /* 4651 * Set valid range. This is typically the entire buffer and thus the 4652 * entire page. 4653 */ 4654 if (eoff > soff) { 4655 vm_page_set_validclean( 4656 m, 4657 (vm_offset_t) (soff & PAGE_MASK), 4658 (vm_offset_t) (eoff - soff) 4659 ); 4660 } 4661 } 4662 4663 /* 4664 * Acquire a shared busy on all pages in the buf. 4665 */ 4666 void 4667 vfs_busy_pages_acquire(struct buf *bp) 4668 { 4669 int i; 4670 4671 for (i = 0; i < bp->b_npages; i++) 4672 vm_page_busy_acquire(bp->b_pages[i], VM_ALLOC_SBUSY); 4673 } 4674 4675 void 4676 vfs_busy_pages_release(struct buf *bp) 4677 { 4678 int i; 4679 4680 for (i = 0; i < bp->b_npages; i++) 4681 vm_page_sunbusy(bp->b_pages[i]); 4682 } 4683 4684 /* 4685 * This routine is called before a device strategy routine. 4686 * It is used to tell the VM system that paging I/O is in 4687 * progress, and treat the pages associated with the buffer 4688 * almost as being exclusive busy. Also the object paging_in_progress 4689 * flag is handled to make sure that the object doesn't become 4690 * inconsistent. 4691 * 4692 * Since I/O has not been initiated yet, certain buffer flags 4693 * such as BIO_ERROR or B_INVAL may be in an inconsistent state 4694 * and should be ignored. 4695 */ 4696 void 4697 vfs_busy_pages(struct buf *bp, int clear_modify) 4698 { 4699 vm_object_t obj; 4700 vm_ooffset_t foff; 4701 vm_page_t m; 4702 int i; 4703 bool bogus; 4704 4705 if (!(bp->b_flags & B_VMIO)) 4706 return; 4707 4708 obj = bp->b_bufobj->bo_object; 4709 foff = bp->b_offset; 4710 KASSERT(bp->b_offset != NOOFFSET, 4711 ("vfs_busy_pages: no buffer offset")); 4712 if ((bp->b_flags & B_CLUSTER) == 0) { 4713 vm_object_pip_add(obj, bp->b_npages); 4714 vfs_busy_pages_acquire(bp); 4715 } 4716 if (bp->b_bufsize != 0) 4717 vfs_setdirty_range(bp); 4718 bogus = false; 4719 for (i = 0; i < bp->b_npages; i++) { 4720 m = bp->b_pages[i]; 4721 vm_page_assert_sbusied(m); 4722 4723 /* 4724 * When readying a buffer for a read ( i.e 4725 * clear_modify == 0 ), it is important to do 4726 * bogus_page replacement for valid pages in 4727 * partially instantiated buffers. Partially 4728 * instantiated buffers can, in turn, occur when 4729 * reconstituting a buffer from its VM backing store 4730 * base. We only have to do this if B_CACHE is 4731 * clear ( which causes the I/O to occur in the 4732 * first place ). The replacement prevents the read 4733 * I/O from overwriting potentially dirty VM-backed 4734 * pages. XXX bogus page replacement is, uh, bogus. 4735 * It may not work properly with small-block devices. 4736 * We need to find a better way. 4737 */ 4738 if (clear_modify) { 4739 pmap_remove_write(m); 4740 vfs_page_set_validclean(bp, foff, m); 4741 } else if (vm_page_all_valid(m) && 4742 (bp->b_flags & B_CACHE) == 0) { 4743 bp->b_pages[i] = bogus_page; 4744 bogus = true; 4745 } 4746 foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK; 4747 } 4748 if (bogus && buf_mapped(bp)) { 4749 BUF_CHECK_MAPPED(bp); 4750 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), 4751 bp->b_pages, bp->b_npages); 4752 } 4753 } 4754 4755 /* 4756 * vfs_bio_set_valid: 4757 * 4758 * Set the range within the buffer to valid. The range is 4759 * relative to the beginning of the buffer, b_offset. Note that 4760 * b_offset itself may be offset from the beginning of the first 4761 * page. 4762 */ 4763 void 4764 vfs_bio_set_valid(struct buf *bp, int base, int size) 4765 { 4766 int i, n; 4767 vm_page_t m; 4768 4769 if (!(bp->b_flags & B_VMIO)) 4770 return; 4771 4772 /* 4773 * Fixup base to be relative to beginning of first page. 4774 * Set initial n to be the maximum number of bytes in the 4775 * first page that can be validated. 4776 */ 4777 base += (bp->b_offset & PAGE_MASK); 4778 n = PAGE_SIZE - (base & PAGE_MASK); 4779 4780 /* 4781 * Busy may not be strictly necessary here because the pages are 4782 * unlikely to be fully valid and the vnode lock will synchronize 4783 * their access via getpages. It is grabbed for consistency with 4784 * other page validation. 4785 */ 4786 vfs_busy_pages_acquire(bp); 4787 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4788 m = bp->b_pages[i]; 4789 if (n > size) 4790 n = size; 4791 vm_page_set_valid_range(m, base & PAGE_MASK, n); 4792 base += n; 4793 size -= n; 4794 n = PAGE_SIZE; 4795 } 4796 vfs_busy_pages_release(bp); 4797 } 4798 4799 /* 4800 * vfs_bio_clrbuf: 4801 * 4802 * If the specified buffer is a non-VMIO buffer, clear the entire 4803 * buffer. If the specified buffer is a VMIO buffer, clear and 4804 * validate only the previously invalid portions of the buffer. 4805 * This routine essentially fakes an I/O, so we need to clear 4806 * BIO_ERROR and B_INVAL. 4807 * 4808 * Note that while we only theoretically need to clear through b_bcount, 4809 * we go ahead and clear through b_bufsize. 4810 */ 4811 void 4812 vfs_bio_clrbuf(struct buf *bp) 4813 { 4814 int i, j, mask, sa, ea, slide; 4815 4816 if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) { 4817 clrbuf(bp); 4818 return; 4819 } 4820 bp->b_flags &= ~B_INVAL; 4821 bp->b_ioflags &= ~BIO_ERROR; 4822 vfs_busy_pages_acquire(bp); 4823 sa = bp->b_offset & PAGE_MASK; 4824 slide = 0; 4825 for (i = 0; i < bp->b_npages; i++, sa = 0) { 4826 slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize); 4827 ea = slide & PAGE_MASK; 4828 if (ea == 0) 4829 ea = PAGE_SIZE; 4830 if (bp->b_pages[i] == bogus_page) 4831 continue; 4832 j = sa / DEV_BSIZE; 4833 mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j; 4834 if ((bp->b_pages[i]->valid & mask) == mask) 4835 continue; 4836 if ((bp->b_pages[i]->valid & mask) == 0) 4837 pmap_zero_page_area(bp->b_pages[i], sa, ea - sa); 4838 else { 4839 for (; sa < ea; sa += DEV_BSIZE, j++) { 4840 if ((bp->b_pages[i]->valid & (1 << j)) == 0) { 4841 pmap_zero_page_area(bp->b_pages[i], 4842 sa, DEV_BSIZE); 4843 } 4844 } 4845 } 4846 vm_page_set_valid_range(bp->b_pages[i], j * DEV_BSIZE, 4847 roundup2(ea - sa, DEV_BSIZE)); 4848 } 4849 vfs_busy_pages_release(bp); 4850 bp->b_resid = 0; 4851 } 4852 4853 void 4854 vfs_bio_bzero_buf(struct buf *bp, int base, int size) 4855 { 4856 vm_page_t m; 4857 int i, n; 4858 4859 if (buf_mapped(bp)) { 4860 BUF_CHECK_MAPPED(bp); 4861 bzero(bp->b_data + base, size); 4862 } else { 4863 BUF_CHECK_UNMAPPED(bp); 4864 n = PAGE_SIZE - (base & PAGE_MASK); 4865 for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) { 4866 m = bp->b_pages[i]; 4867 if (n > size) 4868 n = size; 4869 pmap_zero_page_area(m, base & PAGE_MASK, n); 4870 base += n; 4871 size -= n; 4872 n = PAGE_SIZE; 4873 } 4874 } 4875 } 4876 4877 /* 4878 * Update buffer flags based on I/O request parameters, optionally releasing the 4879 * buffer. If it's VMIO or direct I/O, the buffer pages are released to the VM, 4880 * where they may be placed on a page queue (VMIO) or freed immediately (direct 4881 * I/O). Otherwise the buffer is released to the cache. 4882 */ 4883 static void 4884 b_io_dismiss(struct buf *bp, int ioflag, bool release) 4885 { 4886 4887 KASSERT((ioflag & IO_NOREUSE) == 0 || (ioflag & IO_VMIO) != 0, 4888 ("buf %p non-VMIO noreuse", bp)); 4889 4890 if ((ioflag & IO_DIRECT) != 0) 4891 bp->b_flags |= B_DIRECT; 4892 if ((ioflag & IO_EXT) != 0) 4893 bp->b_xflags |= BX_ALTDATA; 4894 if ((ioflag & (IO_VMIO | IO_DIRECT)) != 0 && LIST_EMPTY(&bp->b_dep)) { 4895 bp->b_flags |= B_RELBUF; 4896 if ((ioflag & IO_NOREUSE) != 0) 4897 bp->b_flags |= B_NOREUSE; 4898 if (release) 4899 brelse(bp); 4900 } else if (release) 4901 bqrelse(bp); 4902 } 4903 4904 void 4905 vfs_bio_brelse(struct buf *bp, int ioflag) 4906 { 4907 4908 b_io_dismiss(bp, ioflag, true); 4909 } 4910 4911 void 4912 vfs_bio_set_flags(struct buf *bp, int ioflag) 4913 { 4914 4915 b_io_dismiss(bp, ioflag, false); 4916 } 4917 4918 /* 4919 * vm_hold_load_pages and vm_hold_free_pages get pages into 4920 * a buffers address space. The pages are anonymous and are 4921 * not associated with a file object. 4922 */ 4923 static void 4924 vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to) 4925 { 4926 vm_offset_t pg; 4927 vm_page_t p; 4928 int index; 4929 4930 BUF_CHECK_MAPPED(bp); 4931 4932 to = round_page(to); 4933 from = round_page(from); 4934 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 4935 MPASS((bp->b_flags & B_MAXPHYS) == 0); 4936 KASSERT(to - from <= maxbcachebuf, 4937 ("vm_hold_load_pages too large %p %#jx %#jx %u", 4938 bp, (uintmax_t)from, (uintmax_t)to, maxbcachebuf)); 4939 4940 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 4941 /* 4942 * note: must allocate system pages since blocking here 4943 * could interfere with paging I/O, no matter which 4944 * process we are. 4945 */ 4946 p = vm_page_alloc_noobj(VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | 4947 VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT) | VM_ALLOC_WAITOK); 4948 pmap_qenter(pg, &p, 1); 4949 bp->b_pages[index] = p; 4950 } 4951 bp->b_npages = index; 4952 } 4953 4954 /* Return pages associated with this buf to the vm system */ 4955 static void 4956 vm_hold_free_pages(struct buf *bp, int newbsize) 4957 { 4958 vm_offset_t from; 4959 vm_page_t p; 4960 int index, newnpages; 4961 4962 BUF_CHECK_MAPPED(bp); 4963 4964 from = round_page((vm_offset_t)bp->b_data + newbsize); 4965 newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 4966 if (bp->b_npages > newnpages) 4967 pmap_qremove(from, bp->b_npages - newnpages); 4968 for (index = newnpages; index < bp->b_npages; index++) { 4969 p = bp->b_pages[index]; 4970 bp->b_pages[index] = NULL; 4971 vm_page_unwire_noq(p); 4972 vm_page_free(p); 4973 } 4974 bp->b_npages = newnpages; 4975 } 4976 4977 /* 4978 * Map an IO request into kernel virtual address space. 4979 * 4980 * All requests are (re)mapped into kernel VA space. 4981 * Notice that we use b_bufsize for the size of the buffer 4982 * to be mapped. b_bcount might be modified by the driver. 4983 * 4984 * Note that even if the caller determines that the address space should 4985 * be valid, a race or a smaller-file mapped into a larger space may 4986 * actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST 4987 * check the return value. 4988 * 4989 * This function only works with pager buffers. 4990 */ 4991 int 4992 vmapbuf(struct buf *bp, void *uaddr, size_t len, int mapbuf) 4993 { 4994 vm_prot_t prot; 4995 int pidx; 4996 4997 MPASS((bp->b_flags & B_MAXPHYS) != 0); 4998 prot = VM_PROT_READ; 4999 if (bp->b_iocmd == BIO_READ) 5000 prot |= VM_PROT_WRITE; /* Less backwards than it looks */ 5001 pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 5002 (vm_offset_t)uaddr, len, prot, bp->b_pages, PBUF_PAGES); 5003 if (pidx < 0) 5004 return (-1); 5005 bp->b_bufsize = len; 5006 bp->b_npages = pidx; 5007 bp->b_offset = ((vm_offset_t)uaddr) & PAGE_MASK; 5008 if (mapbuf || !unmapped_buf_allowed) { 5009 pmap_qenter((vm_offset_t)bp->b_kvabase, bp->b_pages, pidx); 5010 bp->b_data = bp->b_kvabase + bp->b_offset; 5011 } else 5012 bp->b_data = unmapped_buf; 5013 return (0); 5014 } 5015 5016 /* 5017 * Free the io map PTEs associated with this IO operation. 5018 * We also invalidate the TLB entries and restore the original b_addr. 5019 * 5020 * This function only works with pager buffers. 5021 */ 5022 void 5023 vunmapbuf(struct buf *bp) 5024 { 5025 int npages; 5026 5027 npages = bp->b_npages; 5028 if (buf_mapped(bp)) 5029 pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages); 5030 vm_page_unhold_pages(bp->b_pages, npages); 5031 5032 bp->b_data = unmapped_buf; 5033 } 5034 5035 void 5036 bdone(struct buf *bp) 5037 { 5038 struct mtx *mtxp; 5039 5040 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5041 mtx_lock(mtxp); 5042 bp->b_flags |= B_DONE; 5043 wakeup(bp); 5044 mtx_unlock(mtxp); 5045 } 5046 5047 void 5048 bwait(struct buf *bp, u_char pri, const char *wchan) 5049 { 5050 struct mtx *mtxp; 5051 5052 mtxp = mtx_pool_find(mtxpool_sleep, bp); 5053 mtx_lock(mtxp); 5054 while ((bp->b_flags & B_DONE) == 0) 5055 msleep(bp, mtxp, pri, wchan, 0); 5056 mtx_unlock(mtxp); 5057 } 5058 5059 int 5060 bufsync(struct bufobj *bo, int waitfor) 5061 { 5062 5063 return (VOP_FSYNC(bo2vnode(bo), waitfor, curthread)); 5064 } 5065 5066 void 5067 bufstrategy(struct bufobj *bo, struct buf *bp) 5068 { 5069 int i __unused; 5070 struct vnode *vp; 5071 5072 vp = bp->b_vp; 5073 KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy")); 5074 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 5075 ("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp)); 5076 i = VOP_STRATEGY(vp, bp); 5077 KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp)); 5078 } 5079 5080 /* 5081 * Initialize a struct bufobj before use. Memory is assumed zero filled. 5082 */ 5083 void 5084 bufobj_init(struct bufobj *bo, void *private) 5085 { 5086 static volatile int bufobj_cleanq; 5087 5088 bo->bo_domain = 5089 atomic_fetchadd_int(&bufobj_cleanq, 1) % buf_domains; 5090 rw_init(BO_LOCKPTR(bo), "bufobj interlock"); 5091 bo->bo_private = private; 5092 TAILQ_INIT(&bo->bo_clean.bv_hd); 5093 TAILQ_INIT(&bo->bo_dirty.bv_hd); 5094 } 5095 5096 void 5097 bufobj_wrefl(struct bufobj *bo) 5098 { 5099 5100 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5101 ASSERT_BO_WLOCKED(bo); 5102 bo->bo_numoutput++; 5103 } 5104 5105 void 5106 bufobj_wref(struct bufobj *bo) 5107 { 5108 5109 KASSERT(bo != NULL, ("NULL bo in bufobj_wref")); 5110 BO_LOCK(bo); 5111 bo->bo_numoutput++; 5112 BO_UNLOCK(bo); 5113 } 5114 5115 void 5116 bufobj_wdrop(struct bufobj *bo) 5117 { 5118 5119 KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop")); 5120 BO_LOCK(bo); 5121 KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count")); 5122 if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) { 5123 bo->bo_flag &= ~BO_WWAIT; 5124 wakeup(&bo->bo_numoutput); 5125 } 5126 BO_UNLOCK(bo); 5127 } 5128 5129 int 5130 bufobj_wwait(struct bufobj *bo, int slpflag, int timeo) 5131 { 5132 int error; 5133 5134 KASSERT(bo != NULL, ("NULL bo in bufobj_wwait")); 5135 ASSERT_BO_WLOCKED(bo); 5136 error = 0; 5137 while (bo->bo_numoutput) { 5138 bo->bo_flag |= BO_WWAIT; 5139 error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo), 5140 slpflag | (PRIBIO + 1), "bo_wwait", timeo); 5141 if (error) 5142 break; 5143 } 5144 return (error); 5145 } 5146 5147 /* 5148 * Set bio_data or bio_ma for struct bio from the struct buf. 5149 */ 5150 void 5151 bdata2bio(struct buf *bp, struct bio *bip) 5152 { 5153 5154 if (!buf_mapped(bp)) { 5155 KASSERT(unmapped_buf_allowed, ("unmapped")); 5156 bip->bio_ma = bp->b_pages; 5157 bip->bio_ma_n = bp->b_npages; 5158 bip->bio_data = unmapped_buf; 5159 bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK; 5160 bip->bio_flags |= BIO_UNMAPPED; 5161 KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) / 5162 PAGE_SIZE == bp->b_npages, 5163 ("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset, 5164 (long long)bip->bio_length, bip->bio_ma_n)); 5165 } else { 5166 bip->bio_data = bp->b_data; 5167 bip->bio_ma = NULL; 5168 } 5169 } 5170 5171 /* 5172 * The MIPS pmap code currently doesn't handle aliased pages. 5173 * The VIPT caches may not handle page aliasing themselves, leading 5174 * to data corruption. 5175 * 5176 * As such, this code makes a system extremely unhappy if said 5177 * system doesn't support unaliasing the above situation in hardware. 5178 * Some "recent" systems (eg some mips24k/mips74k cores) don't enable 5179 * this feature at build time, so it has to be handled in software. 5180 * 5181 * Once the MIPS pmap/cache code grows to support this function on 5182 * earlier chips, it should be flipped back off. 5183 */ 5184 #ifdef __mips__ 5185 static int buf_pager_relbuf = 1; 5186 #else 5187 static int buf_pager_relbuf = 0; 5188 #endif 5189 SYSCTL_INT(_vfs, OID_AUTO, buf_pager_relbuf, CTLFLAG_RWTUN, 5190 &buf_pager_relbuf, 0, 5191 "Make buffer pager release buffers after reading"); 5192 5193 /* 5194 * The buffer pager. It uses buffer reads to validate pages. 5195 * 5196 * In contrast to the generic local pager from vm/vnode_pager.c, this 5197 * pager correctly and easily handles volumes where the underlying 5198 * device block size is greater than the machine page size. The 5199 * buffer cache transparently extends the requested page run to be 5200 * aligned at the block boundary, and does the necessary bogus page 5201 * replacements in the addends to avoid obliterating already valid 5202 * pages. 5203 * 5204 * The only non-trivial issue is that the exclusive busy state for 5205 * pages, which is assumed by the vm_pager_getpages() interface, is 5206 * incompatible with the VMIO buffer cache's desire to share-busy the 5207 * pages. This function performs a trivial downgrade of the pages' 5208 * state before reading buffers, and a less trivial upgrade from the 5209 * shared-busy to excl-busy state after the read. 5210 */ 5211 int 5212 vfs_bio_getpages(struct vnode *vp, vm_page_t *ma, int count, 5213 int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno, 5214 vbg_get_blksize_t get_blksize) 5215 { 5216 vm_page_t m; 5217 vm_object_t object; 5218 struct buf *bp; 5219 struct mount *mp; 5220 daddr_t lbn, lbnp; 5221 vm_ooffset_t la, lb, poff, poffe; 5222 long bo_bs, bsize; 5223 int br_flags, error, i, pgsin, pgsin_a, pgsin_b; 5224 bool redo, lpart; 5225 5226 object = vp->v_object; 5227 mp = vp->v_mount; 5228 error = 0; 5229 la = IDX_TO_OFF(ma[count - 1]->pindex); 5230 if (la >= object->un_pager.vnp.vnp_size) 5231 return (VM_PAGER_BAD); 5232 5233 /* 5234 * Change the meaning of la from where the last requested page starts 5235 * to where it ends, because that's the end of the requested region 5236 * and the start of the potential read-ahead region. 5237 */ 5238 la += PAGE_SIZE; 5239 lpart = la > object->un_pager.vnp.vnp_size; 5240 error = get_blksize(vp, get_lblkno(vp, IDX_TO_OFF(ma[0]->pindex)), 5241 &bo_bs); 5242 if (error != 0) 5243 return (VM_PAGER_ERROR); 5244 5245 /* 5246 * Calculate read-ahead, behind and total pages. 5247 */ 5248 pgsin = count; 5249 lb = IDX_TO_OFF(ma[0]->pindex); 5250 pgsin_b = OFF_TO_IDX(lb - rounddown2(lb, bo_bs)); 5251 pgsin += pgsin_b; 5252 if (rbehind != NULL) 5253 *rbehind = pgsin_b; 5254 pgsin_a = OFF_TO_IDX(roundup2(la, bo_bs) - la); 5255 if (la + IDX_TO_OFF(pgsin_a) >= object->un_pager.vnp.vnp_size) 5256 pgsin_a = OFF_TO_IDX(roundup2(object->un_pager.vnp.vnp_size, 5257 PAGE_SIZE) - la); 5258 pgsin += pgsin_a; 5259 if (rahead != NULL) 5260 *rahead = pgsin_a; 5261 VM_CNT_INC(v_vnodein); 5262 VM_CNT_ADD(v_vnodepgsin, pgsin); 5263 5264 br_flags = (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) 5265 != 0) ? GB_UNMAPPED : 0; 5266 again: 5267 for (i = 0; i < count; i++) { 5268 if (ma[i] != bogus_page) 5269 vm_page_busy_downgrade(ma[i]); 5270 } 5271 5272 lbnp = -1; 5273 for (i = 0; i < count; i++) { 5274 m = ma[i]; 5275 if (m == bogus_page) 5276 continue; 5277 5278 /* 5279 * Pages are shared busy and the object lock is not 5280 * owned, which together allow for the pages' 5281 * invalidation. The racy test for validity avoids 5282 * useless creation of the buffer for the most typical 5283 * case when invalidation is not used in redo or for 5284 * parallel read. The shared->excl upgrade loop at 5285 * the end of the function catches the race in a 5286 * reliable way (protected by the object lock). 5287 */ 5288 if (vm_page_all_valid(m)) 5289 continue; 5290 5291 poff = IDX_TO_OFF(m->pindex); 5292 poffe = MIN(poff + PAGE_SIZE, object->un_pager.vnp.vnp_size); 5293 for (; poff < poffe; poff += bsize) { 5294 lbn = get_lblkno(vp, poff); 5295 if (lbn == lbnp) 5296 goto next_page; 5297 lbnp = lbn; 5298 5299 error = get_blksize(vp, lbn, &bsize); 5300 if (error == 0) 5301 error = bread_gb(vp, lbn, bsize, 5302 curthread->td_ucred, br_flags, &bp); 5303 if (error != 0) 5304 goto end_pages; 5305 if (bp->b_rcred == curthread->td_ucred) { 5306 crfree(bp->b_rcred); 5307 bp->b_rcred = NOCRED; 5308 } 5309 if (LIST_EMPTY(&bp->b_dep)) { 5310 /* 5311 * Invalidation clears m->valid, but 5312 * may leave B_CACHE flag if the 5313 * buffer existed at the invalidation 5314 * time. In this case, recycle the 5315 * buffer to do real read on next 5316 * bread() after redo. 5317 * 5318 * Otherwise B_RELBUF is not strictly 5319 * necessary, enable to reduce buf 5320 * cache pressure. 5321 */ 5322 if (buf_pager_relbuf || 5323 !vm_page_all_valid(m)) 5324 bp->b_flags |= B_RELBUF; 5325 5326 bp->b_flags &= ~B_NOCACHE; 5327 brelse(bp); 5328 } else { 5329 bqrelse(bp); 5330 } 5331 } 5332 KASSERT(1 /* racy, enable for debugging */ || 5333 vm_page_all_valid(m) || i == count - 1, 5334 ("buf %d %p invalid", i, m)); 5335 if (i == count - 1 && lpart) { 5336 if (!vm_page_none_valid(m) && 5337 !vm_page_all_valid(m)) 5338 vm_page_zero_invalid(m, TRUE); 5339 } 5340 next_page:; 5341 } 5342 end_pages: 5343 5344 redo = false; 5345 for (i = 0; i < count; i++) { 5346 if (ma[i] == bogus_page) 5347 continue; 5348 if (vm_page_busy_tryupgrade(ma[i]) == 0) { 5349 vm_page_sunbusy(ma[i]); 5350 ma[i] = vm_page_grab_unlocked(object, ma[i]->pindex, 5351 VM_ALLOC_NORMAL); 5352 } 5353 5354 /* 5355 * Since the pages were only sbusy while neither the 5356 * buffer nor the object lock was held by us, or 5357 * reallocated while vm_page_grab() slept for busy 5358 * relinguish, they could have been invalidated. 5359 * Recheck the valid bits and re-read as needed. 5360 * 5361 * Note that the last page is made fully valid in the 5362 * read loop, and partial validity for the page at 5363 * index count - 1 could mean that the page was 5364 * invalidated or removed, so we must restart for 5365 * safety as well. 5366 */ 5367 if (!vm_page_all_valid(ma[i])) 5368 redo = true; 5369 } 5370 if (redo && error == 0) 5371 goto again; 5372 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 5373 } 5374 5375 #include "opt_ddb.h" 5376 #ifdef DDB 5377 #include <ddb/ddb.h> 5378 5379 /* DDB command to show buffer data */ 5380 DB_SHOW_COMMAND(buffer, db_show_buffer) 5381 { 5382 /* get args */ 5383 struct buf *bp = (struct buf *)addr; 5384 #ifdef FULL_BUF_TRACKING 5385 uint32_t i, j; 5386 #endif 5387 5388 if (!have_addr) { 5389 db_printf("usage: show buffer <addr>\n"); 5390 return; 5391 } 5392 5393 db_printf("buf at %p\n", bp); 5394 db_printf("b_flags = 0x%b, b_xflags=0x%b\n", 5395 (u_int)bp->b_flags, PRINT_BUF_FLAGS, 5396 (u_int)bp->b_xflags, PRINT_BUF_XFLAGS); 5397 db_printf("b_vflags=0x%b b_ioflags0x%b\n", 5398 (u_int)bp->b_vflags, PRINT_BUF_VFLAGS, 5399 (u_int)bp->b_ioflags, PRINT_BIO_FLAGS); 5400 db_printf( 5401 "b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n" 5402 "b_bufobj = (%p), b_data = %p\n, b_blkno = %jd, b_lblkno = %jd, " 5403 "b_vp = %p, b_dep = %p\n", 5404 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 5405 bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno, 5406 (intmax_t)bp->b_lblkno, bp->b_vp, bp->b_dep.lh_first); 5407 db_printf("b_kvabase = %p, b_kvasize = %d\n", 5408 bp->b_kvabase, bp->b_kvasize); 5409 if (bp->b_npages) { 5410 int i; 5411 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 5412 for (i = 0; i < bp->b_npages; i++) { 5413 vm_page_t m; 5414 m = bp->b_pages[i]; 5415 if (m != NULL) 5416 db_printf("(%p, 0x%lx, 0x%lx)", m->object, 5417 (u_long)m->pindex, 5418 (u_long)VM_PAGE_TO_PHYS(m)); 5419 else 5420 db_printf("( ??? )"); 5421 if ((i + 1) < bp->b_npages) 5422 db_printf(","); 5423 } 5424 db_printf("\n"); 5425 } 5426 BUF_LOCKPRINTINFO(bp); 5427 #if defined(FULL_BUF_TRACKING) 5428 db_printf("b_io_tracking: b_io_tcnt = %u\n", bp->b_io_tcnt); 5429 5430 i = bp->b_io_tcnt % BUF_TRACKING_SIZE; 5431 for (j = 1; j <= BUF_TRACKING_SIZE; j++) { 5432 if (bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)] == NULL) 5433 continue; 5434 db_printf(" %2u: %s\n", j, 5435 bp->b_io_tracking[BUF_TRACKING_ENTRY(i - j)]); 5436 } 5437 #elif defined(BUF_TRACKING) 5438 db_printf("b_io_tracking: %s\n", bp->b_io_tracking); 5439 #endif 5440 db_printf(" "); 5441 } 5442 5443 DB_SHOW_COMMAND(bufqueues, bufqueues) 5444 { 5445 struct bufdomain *bd; 5446 struct buf *bp; 5447 long total; 5448 int i, j, cnt; 5449 5450 db_printf("bqempty: %d\n", bqempty.bq_len); 5451 5452 for (i = 0; i < buf_domains; i++) { 5453 bd = &bdomain[i]; 5454 db_printf("Buf domain %d\n", i); 5455 db_printf("\tfreebufs\t%d\n", bd->bd_freebuffers); 5456 db_printf("\tlofreebufs\t%d\n", bd->bd_lofreebuffers); 5457 db_printf("\thifreebufs\t%d\n", bd->bd_hifreebuffers); 5458 db_printf("\n"); 5459 db_printf("\tbufspace\t%ld\n", bd->bd_bufspace); 5460 db_printf("\tmaxbufspace\t%ld\n", bd->bd_maxbufspace); 5461 db_printf("\thibufspace\t%ld\n", bd->bd_hibufspace); 5462 db_printf("\tlobufspace\t%ld\n", bd->bd_lobufspace); 5463 db_printf("\tbufspacethresh\t%ld\n", bd->bd_bufspacethresh); 5464 db_printf("\n"); 5465 db_printf("\tnumdirtybuffers\t%d\n", bd->bd_numdirtybuffers); 5466 db_printf("\tlodirtybuffers\t%d\n", bd->bd_lodirtybuffers); 5467 db_printf("\thidirtybuffers\t%d\n", bd->bd_hidirtybuffers); 5468 db_printf("\tdirtybufthresh\t%d\n", bd->bd_dirtybufthresh); 5469 db_printf("\n"); 5470 total = 0; 5471 TAILQ_FOREACH(bp, &bd->bd_cleanq->bq_queue, b_freelist) 5472 total += bp->b_bufsize; 5473 db_printf("\tcleanq count\t%d (%ld)\n", 5474 bd->bd_cleanq->bq_len, total); 5475 total = 0; 5476 TAILQ_FOREACH(bp, &bd->bd_dirtyq.bq_queue, b_freelist) 5477 total += bp->b_bufsize; 5478 db_printf("\tdirtyq count\t%d (%ld)\n", 5479 bd->bd_dirtyq.bq_len, total); 5480 db_printf("\twakeup\t\t%d\n", bd->bd_wanted); 5481 db_printf("\tlim\t\t%d\n", bd->bd_lim); 5482 db_printf("\tCPU "); 5483 for (j = 0; j <= mp_maxid; j++) 5484 db_printf("%d, ", bd->bd_subq[j].bq_len); 5485 db_printf("\n"); 5486 cnt = 0; 5487 total = 0; 5488 for (j = 0; j < nbuf; j++) { 5489 bp = nbufp(j); 5490 if (bp->b_domain == i && BUF_ISLOCKED(bp)) { 5491 cnt++; 5492 total += bp->b_bufsize; 5493 } 5494 } 5495 db_printf("\tLocked buffers: %d space %ld\n", cnt, total); 5496 cnt = 0; 5497 total = 0; 5498 for (j = 0; j < nbuf; j++) { 5499 bp = nbufp(j); 5500 if (bp->b_domain == i) { 5501 cnt++; 5502 total += bp->b_bufsize; 5503 } 5504 } 5505 db_printf("\tTotal buffers: %d space %ld\n", cnt, total); 5506 } 5507 } 5508 5509 DB_SHOW_COMMAND(lockedbufs, lockedbufs) 5510 { 5511 struct buf *bp; 5512 int i; 5513 5514 for (i = 0; i < nbuf; i++) { 5515 bp = nbufp(i); 5516 if (BUF_ISLOCKED(bp)) { 5517 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5518 db_printf("\n"); 5519 if (db_pager_quit) 5520 break; 5521 } 5522 } 5523 } 5524 5525 DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs) 5526 { 5527 struct vnode *vp; 5528 struct buf *bp; 5529 5530 if (!have_addr) { 5531 db_printf("usage: show vnodebufs <addr>\n"); 5532 return; 5533 } 5534 vp = (struct vnode *)addr; 5535 db_printf("Clean buffers:\n"); 5536 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) { 5537 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5538 db_printf("\n"); 5539 } 5540 db_printf("Dirty buffers:\n"); 5541 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) { 5542 db_show_buffer((uintptr_t)bp, 1, 0, NULL); 5543 db_printf("\n"); 5544 } 5545 } 5546 5547 DB_COMMAND(countfreebufs, db_coundfreebufs) 5548 { 5549 struct buf *bp; 5550 int i, used = 0, nfree = 0; 5551 5552 if (have_addr) { 5553 db_printf("usage: countfreebufs\n"); 5554 return; 5555 } 5556 5557 for (i = 0; i < nbuf; i++) { 5558 bp = nbufp(i); 5559 if (bp->b_qindex == QUEUE_EMPTY) 5560 nfree++; 5561 else 5562 used++; 5563 } 5564 5565 db_printf("Counted %d free, %d used (%d tot)\n", nfree, used, 5566 nfree + used); 5567 db_printf("numfreebuffers is %d\n", numfreebuffers); 5568 } 5569 #endif /* DDB */ 5570