kern_alq.c revision 180196
1/*- 2 * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/sys/kern/kern_alq.c 180196 2008-07-02 20:44:33Z rdivacky $"); 29 30#include "opt_mac.h" 31 32#include <sys/param.h> 33#include <sys/systm.h> 34#include <sys/kernel.h> 35#include <sys/kthread.h> 36#include <sys/lock.h> 37#include <sys/mount.h> 38#include <sys/mutex.h> 39#include <sys/namei.h> 40#include <sys/proc.h> 41#include <sys/vnode.h> 42#include <sys/alq.h> 43#include <sys/malloc.h> 44#include <sys/unistd.h> 45#include <sys/fcntl.h> 46#include <sys/eventhandler.h> 47 48#include <security/mac/mac_framework.h> 49 50/* Async. Logging Queue */ 51struct alq { 52 int aq_entmax; /* Max entries */ 53 int aq_entlen; /* Entry length */ 54 char *aq_entbuf; /* Buffer for stored entries */ 55 int aq_flags; /* Queue flags */ 56 struct mtx aq_mtx; /* Queue lock */ 57 struct vnode *aq_vp; /* Open vnode handle */ 58 struct ucred *aq_cred; /* Credentials of the opening thread */ 59 struct ale *aq_first; /* First ent */ 60 struct ale *aq_entfree; /* First free ent */ 61 struct ale *aq_entvalid; /* First ent valid for writing */ 62 LIST_ENTRY(alq) aq_act; /* List of active queues */ 63 LIST_ENTRY(alq) aq_link; /* List of all queues */ 64}; 65 66#define AQ_WANTED 0x0001 /* Wakeup sleeper when io is done */ 67#define AQ_ACTIVE 0x0002 /* on the active list */ 68#define AQ_FLUSHING 0x0004 /* doing IO */ 69#define AQ_SHUTDOWN 0x0008 /* Queue no longer valid */ 70 71#define ALQ_LOCK(alq) mtx_lock_spin(&(alq)->aq_mtx) 72#define ALQ_UNLOCK(alq) mtx_unlock_spin(&(alq)->aq_mtx) 73 74static MALLOC_DEFINE(M_ALD, "ALD", "ALD"); 75 76/* 77 * The ald_mtx protects the ald_queues list and the ald_active list. 78 */ 79static struct mtx ald_mtx; 80static LIST_HEAD(, alq) ald_queues; 81static LIST_HEAD(, alq) ald_active; 82static int ald_shutingdown = 0; 83struct thread *ald_thread; 84static struct proc *ald_proc; 85 86#define ALD_LOCK() mtx_lock(&ald_mtx) 87#define ALD_UNLOCK() mtx_unlock(&ald_mtx) 88 89/* Daemon functions */ 90static int ald_add(struct alq *); 91static int ald_rem(struct alq *); 92static void ald_startup(void *); 93static void ald_daemon(void); 94static void ald_shutdown(void *, int); 95static void ald_activate(struct alq *); 96static void ald_deactivate(struct alq *); 97 98/* Internal queue functions */ 99static void alq_shutdown(struct alq *); 100static int alq_doio(struct alq *); 101 102 103/* 104 * Add a new queue to the global list. Fail if we're shutting down. 105 */ 106static int 107ald_add(struct alq *alq) 108{ 109 int error; 110 111 error = 0; 112 113 ALD_LOCK(); 114 if (ald_shutingdown) { 115 error = EBUSY; 116 goto done; 117 } 118 LIST_INSERT_HEAD(&ald_queues, alq, aq_link); 119done: 120 ALD_UNLOCK(); 121 return (error); 122} 123 124/* 125 * Remove a queue from the global list unless we're shutting down. If so, 126 * the ald will take care of cleaning up it's resources. 127 */ 128static int 129ald_rem(struct alq *alq) 130{ 131 int error; 132 133 error = 0; 134 135 ALD_LOCK(); 136 if (ald_shutingdown) { 137 error = EBUSY; 138 goto done; 139 } 140 LIST_REMOVE(alq, aq_link); 141done: 142 ALD_UNLOCK(); 143 return (error); 144} 145 146/* 147 * Put a queue on the active list. This will schedule it for writing. 148 */ 149static void 150ald_activate(struct alq *alq) 151{ 152 LIST_INSERT_HEAD(&ald_active, alq, aq_act); 153 wakeup(&ald_active); 154} 155 156static void 157ald_deactivate(struct alq *alq) 158{ 159 LIST_REMOVE(alq, aq_act); 160 alq->aq_flags &= ~AQ_ACTIVE; 161} 162 163static void 164ald_startup(void *unused) 165{ 166 mtx_init(&ald_mtx, "ALDmtx", NULL, MTX_DEF|MTX_QUIET); 167 LIST_INIT(&ald_queues); 168 LIST_INIT(&ald_active); 169} 170 171static void 172ald_daemon(void) 173{ 174 int needwakeup; 175 struct alq *alq; 176 177 ald_thread = FIRST_THREAD_IN_PROC(ald_proc); 178 179 EVENTHANDLER_REGISTER(shutdown_pre_sync, ald_shutdown, NULL, 180 SHUTDOWN_PRI_FIRST); 181 182 ALD_LOCK(); 183 184 for (;;) { 185 while ((alq = LIST_FIRST(&ald_active)) == NULL) 186 msleep(&ald_active, &ald_mtx, PWAIT, "aldslp", 0); 187 188 ALQ_LOCK(alq); 189 ald_deactivate(alq); 190 ALD_UNLOCK(); 191 needwakeup = alq_doio(alq); 192 ALQ_UNLOCK(alq); 193 if (needwakeup) 194 wakeup(alq); 195 ALD_LOCK(); 196 } 197} 198 199static void 200ald_shutdown(void *arg, int howto) 201{ 202 struct alq *alq; 203 204 ALD_LOCK(); 205 ald_shutingdown = 1; 206 207 while ((alq = LIST_FIRST(&ald_queues)) != NULL) { 208 LIST_REMOVE(alq, aq_link); 209 ALD_UNLOCK(); 210 alq_shutdown(alq); 211 ALD_LOCK(); 212 } 213 ALD_UNLOCK(); 214} 215 216static void 217alq_shutdown(struct alq *alq) 218{ 219 ALQ_LOCK(alq); 220 221 /* Stop any new writers. */ 222 alq->aq_flags |= AQ_SHUTDOWN; 223 224 /* Drain IO */ 225 while (alq->aq_flags & (AQ_FLUSHING|AQ_ACTIVE)) { 226 alq->aq_flags |= AQ_WANTED; 227 msleep_spin(alq, &alq->aq_mtx, "aldclose", 0); 228 } 229 ALQ_UNLOCK(alq); 230 231 vn_close(alq->aq_vp, FWRITE, alq->aq_cred, 232 curthread); 233 crfree(alq->aq_cred); 234} 235 236/* 237 * Flush all pending data to disk. This operation will block. 238 */ 239static int 240alq_doio(struct alq *alq) 241{ 242 struct thread *td; 243 struct mount *mp; 244 struct vnode *vp; 245 struct uio auio; 246 struct iovec aiov[2]; 247 struct ale *ale; 248 struct ale *alstart; 249 int totlen; 250 int iov; 251 int vfslocked; 252 253 vp = alq->aq_vp; 254 td = curthread; 255 totlen = 0; 256 iov = 0; 257 258 alstart = ale = alq->aq_entvalid; 259 alq->aq_entvalid = NULL; 260 261 bzero(&aiov, sizeof(aiov)); 262 bzero(&auio, sizeof(auio)); 263 264 do { 265 if (aiov[iov].iov_base == NULL) 266 aiov[iov].iov_base = ale->ae_data; 267 aiov[iov].iov_len += alq->aq_entlen; 268 totlen += alq->aq_entlen; 269 /* Check to see if we're wrapping the buffer */ 270 if (ale->ae_data + alq->aq_entlen != ale->ae_next->ae_data) 271 iov++; 272 ale->ae_flags &= ~AE_VALID; 273 ale = ale->ae_next; 274 } while (ale->ae_flags & AE_VALID); 275 276 alq->aq_flags |= AQ_FLUSHING; 277 ALQ_UNLOCK(alq); 278 279 if (iov == 2 || aiov[iov].iov_base == NULL) 280 iov--; 281 282 auio.uio_iov = &aiov[0]; 283 auio.uio_offset = 0; 284 auio.uio_segflg = UIO_SYSSPACE; 285 auio.uio_rw = UIO_WRITE; 286 auio.uio_iovcnt = iov + 1; 287 auio.uio_resid = totlen; 288 auio.uio_td = td; 289 290 /* 291 * Do all of the junk required to write now. 292 */ 293 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 294 vn_start_write(vp, &mp, V_WAIT); 295 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 296 VOP_LEASE(vp, td, alq->aq_cred, LEASE_WRITE); 297 /* 298 * XXX: VOP_WRITE error checks are ignored. 299 */ 300#ifdef MAC 301 if (mac_vnode_check_write(alq->aq_cred, NOCRED, vp) == 0) 302#endif 303 VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, alq->aq_cred); 304 VOP_UNLOCK(vp, 0); 305 vn_finished_write(mp); 306 VFS_UNLOCK_GIANT(vfslocked); 307 308 ALQ_LOCK(alq); 309 alq->aq_flags &= ~AQ_FLUSHING; 310 311 if (alq->aq_entfree == NULL) 312 alq->aq_entfree = alstart; 313 314 if (alq->aq_flags & AQ_WANTED) { 315 alq->aq_flags &= ~AQ_WANTED; 316 return (1); 317 } 318 319 return(0); 320} 321 322static struct kproc_desc ald_kp = { 323 "ALQ Daemon", 324 ald_daemon, 325 &ald_proc 326}; 327 328SYSINIT(aldthread, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, kproc_start, &ald_kp); 329SYSINIT(ald, SI_SUB_LOCK, SI_ORDER_ANY, ald_startup, NULL); 330 331 332/* User visible queue functions */ 333 334/* 335 * Create the queue data structure, allocate the buffer, and open the file. 336 */ 337int 338alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode, 339 int size, int count) 340{ 341 struct thread *td; 342 struct nameidata nd; 343 struct ale *ale; 344 struct ale *alp; 345 struct alq *alq; 346 char *bufp; 347 int flags; 348 int error; 349 int i, vfslocked; 350 351 *alqp = NULL; 352 td = curthread; 353 354 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_SYSSPACE, file, td); 355 flags = FWRITE | O_NOFOLLOW | O_CREAT; 356 357 error = vn_open_cred(&nd, &flags, cmode, cred, NULL); 358 if (error) 359 return (error); 360 361 vfslocked = NDHASGIANT(&nd); 362 NDFREE(&nd, NDF_ONLY_PNBUF); 363 /* We just unlock so we hold a reference */ 364 VOP_UNLOCK(nd.ni_vp, 0); 365 VFS_UNLOCK_GIANT(vfslocked); 366 367 alq = malloc(sizeof(*alq), M_ALD, M_WAITOK|M_ZERO); 368 alq->aq_entbuf = malloc(count * size, M_ALD, M_WAITOK|M_ZERO); 369 alq->aq_first = malloc(sizeof(*ale) * count, M_ALD, M_WAITOK|M_ZERO); 370 alq->aq_vp = nd.ni_vp; 371 alq->aq_cred = crhold(cred); 372 alq->aq_entmax = count; 373 alq->aq_entlen = size; 374 alq->aq_entfree = alq->aq_first; 375 376 mtx_init(&alq->aq_mtx, "ALD Queue", NULL, MTX_SPIN|MTX_QUIET); 377 378 bufp = alq->aq_entbuf; 379 ale = alq->aq_first; 380 alp = NULL; 381 382 /* Match up entries with buffers */ 383 for (i = 0; i < count; i++) { 384 if (alp) 385 alp->ae_next = ale; 386 ale->ae_data = bufp; 387 alp = ale; 388 ale++; 389 bufp += size; 390 } 391 392 alp->ae_next = alq->aq_first; 393 394 if ((error = ald_add(alq)) != 0) 395 return (error); 396 *alqp = alq; 397 398 return (0); 399} 400 401/* 402 * Copy a new entry into the queue. If the operation would block either 403 * wait or return an error depending on the value of waitok. 404 */ 405int 406alq_write(struct alq *alq, void *data, int waitok) 407{ 408 struct ale *ale; 409 410 if ((ale = alq_get(alq, waitok)) == NULL) 411 return (EWOULDBLOCK); 412 413 bcopy(data, ale->ae_data, alq->aq_entlen); 414 alq_post(alq, ale); 415 416 return (0); 417} 418 419struct ale * 420alq_get(struct alq *alq, int waitok) 421{ 422 struct ale *ale; 423 struct ale *aln; 424 425 ale = NULL; 426 427 ALQ_LOCK(alq); 428 429 /* Loop until we get an entry or we're shutting down */ 430 while ((alq->aq_flags & AQ_SHUTDOWN) == 0 && 431 (ale = alq->aq_entfree) == NULL && 432 (waitok & ALQ_WAITOK)) { 433 alq->aq_flags |= AQ_WANTED; 434 msleep_spin(alq, &alq->aq_mtx, "alqget", 0); 435 } 436 437 if (ale != NULL) { 438 aln = ale->ae_next; 439 if ((aln->ae_flags & AE_VALID) == 0) 440 alq->aq_entfree = aln; 441 else 442 alq->aq_entfree = NULL; 443 } else 444 ALQ_UNLOCK(alq); 445 446 447 return (ale); 448} 449 450void 451alq_post(struct alq *alq, struct ale *ale) 452{ 453 int activate; 454 455 ale->ae_flags |= AE_VALID; 456 457 if (alq->aq_entvalid == NULL) 458 alq->aq_entvalid = ale; 459 460 if ((alq->aq_flags & AQ_ACTIVE) == 0) { 461 alq->aq_flags |= AQ_ACTIVE; 462 activate = 1; 463 } else 464 activate = 0; 465 466 ALQ_UNLOCK(alq); 467 if (activate) { 468 ALD_LOCK(); 469 ald_activate(alq); 470 ALD_UNLOCK(); 471 } 472} 473 474void 475alq_flush(struct alq *alq) 476{ 477 int needwakeup = 0; 478 479 ALD_LOCK(); 480 ALQ_LOCK(alq); 481 if (alq->aq_flags & AQ_ACTIVE) { 482 ald_deactivate(alq); 483 ALD_UNLOCK(); 484 needwakeup = alq_doio(alq); 485 } else 486 ALD_UNLOCK(); 487 ALQ_UNLOCK(alq); 488 489 if (needwakeup) 490 wakeup(alq); 491} 492 493/* 494 * Flush remaining data, close the file and free all resources. 495 */ 496void 497alq_close(struct alq *alq) 498{ 499 /* 500 * If we're already shuting down someone else will flush and close 501 * the vnode. 502 */ 503 if (ald_rem(alq) != 0) 504 return; 505 506 /* 507 * Drain all pending IO. 508 */ 509 alq_shutdown(alq); 510 511 mtx_destroy(&alq->aq_mtx); 512 free(alq->aq_first, M_ALD); 513 free(alq->aq_entbuf, M_ALD); 514 free(alq, M_ALD); 515} 516