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