kern_alq.c revision 163606
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 163606 2006-10-22 11:52:19Z rwatson $"); 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 ALQ_UNLOCK(alq); 228 tsleep(alq, PWAIT, "aldclose", 0); 229 ALQ_LOCK(alq); 230 } 231 ALQ_UNLOCK(alq); 232 233 vn_close(alq->aq_vp, FWRITE, alq->aq_cred, 234 curthread); 235 crfree(alq->aq_cred); 236} 237 238/* 239 * Flush all pending data to disk. This operation will block. 240 */ 241static int 242alq_doio(struct alq *alq) 243{ 244 struct thread *td; 245 struct mount *mp; 246 struct vnode *vp; 247 struct uio auio; 248 struct iovec aiov[2]; 249 struct ale *ale; 250 struct ale *alstart; 251 int totlen; 252 int iov; 253 int vfslocked; 254 255 vp = alq->aq_vp; 256 td = curthread; 257 totlen = 0; 258 iov = 0; 259 260 alstart = ale = alq->aq_entvalid; 261 alq->aq_entvalid = NULL; 262 263 bzero(&aiov, sizeof(aiov)); 264 bzero(&auio, sizeof(auio)); 265 266 do { 267 if (aiov[iov].iov_base == NULL) 268 aiov[iov].iov_base = ale->ae_data; 269 aiov[iov].iov_len += alq->aq_entlen; 270 totlen += alq->aq_entlen; 271 /* Check to see if we're wrapping the buffer */ 272 if (ale->ae_data + alq->aq_entlen != ale->ae_next->ae_data) 273 iov++; 274 ale->ae_flags &= ~AE_VALID; 275 ale = ale->ae_next; 276 } while (ale->ae_flags & AE_VALID); 277 278 alq->aq_flags |= AQ_FLUSHING; 279 ALQ_UNLOCK(alq); 280 281 if (iov == 2 || aiov[iov].iov_base == NULL) 282 iov--; 283 284 auio.uio_iov = &aiov[0]; 285 auio.uio_offset = 0; 286 auio.uio_segflg = UIO_SYSSPACE; 287 auio.uio_rw = UIO_WRITE; 288 auio.uio_iovcnt = iov + 1; 289 auio.uio_resid = totlen; 290 auio.uio_td = td; 291 292 /* 293 * Do all of the junk required to write now. 294 */ 295 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 296 vn_start_write(vp, &mp, V_WAIT); 297 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 298 VOP_LEASE(vp, td, alq->aq_cred, LEASE_WRITE); 299 /* 300 * XXX: VOP_WRITE error checks are ignored. 301 */ 302#ifdef MAC 303 if (mac_check_vnode_write(alq->aq_cred, NOCRED, vp) == 0) 304#endif 305 VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, alq->aq_cred); 306 VOP_UNLOCK(vp, 0, td); 307 vn_finished_write(mp); 308 VFS_UNLOCK_GIANT(vfslocked); 309 310 ALQ_LOCK(alq); 311 alq->aq_flags &= ~AQ_FLUSHING; 312 313 if (alq->aq_entfree == NULL) 314 alq->aq_entfree = alstart; 315 316 if (alq->aq_flags & AQ_WANTED) { 317 alq->aq_flags &= ~AQ_WANTED; 318 return (1); 319 } 320 321 return(0); 322} 323 324static struct kproc_desc ald_kp = { 325 "ALQ Daemon", 326 ald_daemon, 327 &ald_proc 328}; 329 330SYSINIT(aldthread, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, kproc_start, &ald_kp) 331SYSINIT(ald, SI_SUB_LOCK, SI_ORDER_ANY, ald_startup, NULL) 332 333 334/* User visible queue functions */ 335 336/* 337 * Create the queue data structure, allocate the buffer, and open the file. 338 */ 339int 340alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode, 341 int size, int count) 342{ 343 struct thread *td; 344 struct nameidata nd; 345 struct ale *ale; 346 struct ale *alp; 347 struct alq *alq; 348 char *bufp; 349 int flags; 350 int error; 351 int i, vfslocked; 352 353 *alqp = NULL; 354 td = curthread; 355 356 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_SYSSPACE, file, td); 357 flags = FWRITE | O_NOFOLLOW | O_CREAT; 358 359 error = vn_open_cred(&nd, &flags, cmode, cred, -1); 360 if (error) 361 return (error); 362 363 vfslocked = NDHASGIANT(&nd); 364 NDFREE(&nd, NDF_ONLY_PNBUF); 365 /* We just unlock so we hold a reference */ 366 VOP_UNLOCK(nd.ni_vp, 0, td); 367 VFS_UNLOCK_GIANT(vfslocked); 368 369 alq = malloc(sizeof(*alq), M_ALD, M_WAITOK|M_ZERO); 370 alq->aq_entbuf = malloc(count * size, M_ALD, M_WAITOK|M_ZERO); 371 alq->aq_first = malloc(sizeof(*ale) * count, M_ALD, M_WAITOK|M_ZERO); 372 alq->aq_vp = nd.ni_vp; 373 alq->aq_cred = crhold(cred); 374 alq->aq_entmax = count; 375 alq->aq_entlen = size; 376 alq->aq_entfree = alq->aq_first; 377 378 mtx_init(&alq->aq_mtx, "ALD Queue", NULL, MTX_SPIN|MTX_QUIET); 379 380 bufp = alq->aq_entbuf; 381 ale = alq->aq_first; 382 alp = NULL; 383 384 /* Match up entries with buffers */ 385 for (i = 0; i < count; i++) { 386 if (alp) 387 alp->ae_next = ale; 388 ale->ae_data = bufp; 389 alp = ale; 390 ale++; 391 bufp += size; 392 } 393 394 alp->ae_next = alq->aq_first; 395 396 if ((error = ald_add(alq)) != 0) 397 return (error); 398 *alqp = alq; 399 400 return (0); 401} 402 403/* 404 * Copy a new entry into the queue. If the operation would block either 405 * wait or return an error depending on the value of waitok. 406 */ 407int 408alq_write(struct alq *alq, void *data, int waitok) 409{ 410 struct ale *ale; 411 412 if ((ale = alq_get(alq, waitok)) == NULL) 413 return (EWOULDBLOCK); 414 415 bcopy(data, ale->ae_data, alq->aq_entlen); 416 alq_post(alq, ale); 417 418 return (0); 419} 420 421struct ale * 422alq_get(struct alq *alq, int waitok) 423{ 424 struct ale *ale; 425 struct ale *aln; 426 427 ale = NULL; 428 429 ALQ_LOCK(alq); 430 431 /* Loop until we get an entry or we're shutting down */ 432 while ((alq->aq_flags & AQ_SHUTDOWN) == 0 && 433 (ale = alq->aq_entfree) == NULL && 434 (waitok & ALQ_WAITOK)) { 435 alq->aq_flags |= AQ_WANTED; 436 ALQ_UNLOCK(alq); 437 tsleep(alq, PWAIT, "alqget", 0); 438 ALQ_LOCK(alq); 439 } 440 441 if (ale != NULL) { 442 aln = ale->ae_next; 443 if ((aln->ae_flags & AE_VALID) == 0) 444 alq->aq_entfree = aln; 445 else 446 alq->aq_entfree = NULL; 447 } else 448 ALQ_UNLOCK(alq); 449 450 451 return (ale); 452} 453 454void 455alq_post(struct alq *alq, struct ale *ale) 456{ 457 int activate; 458 459 ale->ae_flags |= AE_VALID; 460 461 if (alq->aq_entvalid == NULL) 462 alq->aq_entvalid = ale; 463 464 if ((alq->aq_flags & AQ_ACTIVE) == 0) { 465 alq->aq_flags |= AQ_ACTIVE; 466 activate = 1; 467 } else 468 activate = 0; 469 470 ALQ_UNLOCK(alq); 471 if (activate) { 472 ALD_LOCK(); 473 ald_activate(alq); 474 ALD_UNLOCK(); 475 } 476} 477 478void 479alq_flush(struct alq *alq) 480{ 481 int needwakeup = 0; 482 483 ALD_LOCK(); 484 ALQ_LOCK(alq); 485 if (alq->aq_flags & AQ_ACTIVE) { 486 ald_deactivate(alq); 487 ALD_UNLOCK(); 488 needwakeup = alq_doio(alq); 489 } else 490 ALD_UNLOCK(); 491 ALQ_UNLOCK(alq); 492 493 if (needwakeup) 494 wakeup(alq); 495} 496 497/* 498 * Flush remaining data, close the file and free all resources. 499 */ 500void 501alq_close(struct alq *alq) 502{ 503 /* 504 * If we're already shuting down someone else will flush and close 505 * the vnode. 506 */ 507 if (ald_rem(alq) != 0) 508 return; 509 510 /* 511 * Drain all pending IO. 512 */ 513 alq_shutdown(alq); 514 515 mtx_destroy(&alq->aq_mtx); 516 free(alq->aq_first, M_ALD); 517 free(alq->aq_entbuf, M_ALD); 518 free(alq, M_ALD); 519} 520