sys/dev/disk/md/md.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
   5  * can do whatever you want with this stuff. If we meet some day, and you think
   6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   7  * ----------------------------------------------------------------------------
   8  *
   9  * $FreeBSD: src/sys/dev/md/md.c,v 1.8.2.2 2002/08/19 17:43:34 jdp Exp $
  10  * $DragonFly: src/sys/dev/disk/md/md.c,v 1.8 2005/06/06 22:51:54 corecode Exp $
  11  *
  12  */
  13
  14 #include "opt_mfs.h"            /* We have adopted some tasks from MFS */
  15 #include "opt_md.h"             /* We have adopted some tasks from MFS */
  16
  17 #include <sys/param.h>
  18 #include <sys/systm.h>
  19 #include <sys/buf.h>
  20 #include <sys/conf.h>
  21 #include <sys/devicestat.h>
  22 #include <sys/disk.h>
  23 #include <sys/kernel.h>
  24 #include <sys/malloc.h>
  25 #include <sys/sysctl.h>
  26 #include <sys/linker.h>
  27 #include <sys/proc.h>
  28 #include <sys/buf2.h>
  29 #include <sys/thread2.h>
  30
  31 #ifndef MD_NSECT
  32 #define MD_NSECT (10000 * 2)
  33 #endif
  34
  35 MALLOC_DEFINE(M_MD, "MD disk", "Memory Disk");
  36 MALLOC_DEFINE(M_MDSECT, "MD sectors", "Memory Disk Sectors");
  37
  38 static int md_debug;
  39 SYSCTL_INT(_debug, OID_AUTO, mddebug, CTLFLAG_RW, &md_debug, 0, "");
  40
  41 #if defined(MFS_ROOT) && !defined(MD_ROOT)
  42 #define MD_ROOT MFS_ROOT
  43 #warning "option MFS_ROOT has been superceeded by MD_ROOT"
  44 #endif
  45
  46 #if defined(MFS_ROOT_SIZE) && !defined(MD_ROOT_SIZE)
  47 #define MD_ROOT_SIZE MFS_ROOT_SIZE
  48 #warning "option MFS_ROOT_SIZE has been superceeded by MD_ROOT_SIZE"
  49 #endif
  50
  51 #if defined(MD_ROOT) && defined(MD_ROOT_SIZE)
  52 /* Image gets put here: */
  53 static u_char mfs_root[MD_ROOT_SIZE*1024] = "MFS Filesystem goes here";
  54 static u_char end_mfs_root[] __unused = "MFS Filesystem had better STOP here";
  55 #endif
  56
  57 static int mdrootready;
  58
  59 static void mdcreate_malloc(void);
  60
  61 #define CDEV_MAJOR      95
  62
  63 static d_strategy_t mdstrategy;
  64 static d_strategy_t mdstrategy_preload;
  65 static d_strategy_t mdstrategy_malloc;
  66 static d_open_t mdopen;
  67 static d_ioctl_t mdioctl;
  68
  69 static struct cdevsw md_cdevsw = {
  70         /* name */      "md",
  71         /* maj */       CDEV_MAJOR,
  72         /* flags */     D_DISK | D_CANFREE | D_MEMDISK,
  73         /* port */      NULL,
  74         /* clone */     NULL,
  75
  76         /* open */      mdopen,
  77         /* close */     nullclose,
  78         /* read */      physread,
  79         /* write */     physwrite,
  80         /* ioctl */     mdioctl,
  81         /* poll */      nopoll,
  82         /* mmap */      nommap,
  83         /* strategy */  mdstrategy,
  84         /* dump */      nodump,
  85         /* psize */     nopsize,
  86 };
  87
  88 struct md_s {
  89         int unit;
  90         struct devstat stats;
  91         struct buf_queue_head buf_queue;
  92         struct disk disk;
  93         dev_t dev;
  94         int busy;
  95         enum {MD_MALLOC, MD_PRELOAD} type;
  96         unsigned nsect;
  97
  98         /* MD_MALLOC related fields */
  99         unsigned nsecp;
 100         u_char **secp;
 101
 102         /* MD_PRELOAD related fields */
 103         u_char *pl_ptr;
 104         unsigned pl_len;
 105 };
 106
 107 static int mdunits;
 108
 109 static int
 110 mdopen(dev_t dev, int flag, int fmt, struct thread *td)
 111 {
 112         struct md_s *sc;
 113         struct disklabel *dl;
 114
 115         if (md_debug)
 116                 printf("mdopen(%s %x %x %p)\n",
 117                         devtoname(dev), flag, fmt, td);
 118
 119         sc = dev->si_drv1;
 120         if (sc->unit + 1 == mdunits)
 121                 mdcreate_malloc();
 122
 123         dl = &sc->disk.d_label;
 124         bzero(dl, sizeof(*dl));
 125         dl->d_secsize = DEV_BSIZE;
 126         dl->d_nsectors = 1024;
 127         dl->d_ntracks = 1;
 128         dl->d_secpercyl = dl->d_nsectors * dl->d_ntracks;
 129         dl->d_secperunit = sc->nsect;
 130         dl->d_ncylinders = dl->d_secperunit / dl->d_secpercyl;
 131         return (0);
 132 }
 133
 134 static int
 135 mdioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
 136 {
 137
 138         if (md_debug)
 139                 printf("mdioctl(%s %lx %p %x %p)\n",
 140                         devtoname(dev), cmd, addr, flags, td);
 141
 142         return (ENOIOCTL);
 143 }
 144
 145 static void
 146 mdstrategy(struct buf *bp)
 147 {
 148         struct md_s *sc;
 149
 150         if (md_debug > 1)
 151                 printf("mdstrategy(%p) %s %lx, %d, %ld, %p)\n",
 152                     bp, devtoname(bp->b_dev), bp->b_flags, bp->b_blkno,
 153                     bp->b_bcount / DEV_BSIZE, bp->b_data);
 154
 155         sc = bp->b_dev->si_drv1;
 156         if (sc->type == MD_MALLOC) {
 157                 mdstrategy_malloc(bp);
 158         } else {
 159                 mdstrategy_preload(bp);
 160         }
 161         return;
 162 }
 163
 164
 165 static void
 166 mdstrategy_malloc(struct buf *bp)
 167 {
 168         int i;
 169         struct md_s *sc;
 170         devstat_trans_flags dop;
 171         u_char *secp, **secpp, *dst;
 172         unsigned secno, nsec, secval, uc;
 173
 174         if (md_debug > 1)
 175                 printf("mdstrategy_malloc(%p) %s %lx, %d, %ld, %p)\n",
 176                     bp, devtoname(bp->b_dev), bp->b_flags, bp->b_blkno,
 177                     bp->b_bcount / DEV_BSIZE, bp->b_data);
 178
 179         sc = bp->b_dev->si_drv1;
 180
 181         crit_enter();
 182
 183         bufqdisksort(&sc->buf_queue, bp);
 184
 185         if (sc->busy) {
 186                 crit_exit();
 187                 return;
 188         }
 189
 190         sc->busy++;
 191
 192         while (1) {
 193                 bp = bufq_first(&sc->buf_queue);
 194                 if (bp)
 195                         bufq_remove(&sc->buf_queue, bp);
 196                 crit_exit();
 197                 if (!bp)
 198                         break;
 199
 200                 devstat_start_transaction(&sc->stats);
 201
 202                 if (bp->b_flags & B_FREEBUF)
 203                         dop = DEVSTAT_NO_DATA;
 204                 else if (bp->b_flags & B_READ)
 205                         dop = DEVSTAT_READ;
 206                 else
 207                         dop = DEVSTAT_WRITE;
 208
 209                 nsec = bp->b_bcount / DEV_BSIZE;
 210                 secno = bp->b_pblkno;
 211                 dst = bp->b_data;
 212                 while (nsec--) {
 213
 214                         if (secno < sc->nsecp) {
 215                                 secpp = &sc->secp[secno];
 216                                 if ((u_int)*secpp > 255) {
 217                                         secp = *secpp;
 218                                         secval = 0;
 219                                 } else {
 220                                         secp = 0;
 221                                         secval = (u_int) *secpp;
 222                                 }
 223                         } else {
 224                                 secpp = 0;
 225                                 secp = 0;
 226                                 secval = 0;
 227                         }
 228                         if (md_debug > 2)
 229                                 printf("%lx %p %p %d\n", bp->b_flags, secpp, secp, secval);
 230
 231                         if (bp->b_flags & B_FREEBUF) {
 232                                 if (secpp) {
 233                                         if (secp)
 234                                                 FREE(secp, M_MDSECT);
 235                                         *secpp = 0;
 236                                 }
 237                         } else if (bp->b_flags & B_READ) {
 238                                 if (secp) {
 239                                         bcopy(secp, dst, DEV_BSIZE);
 240                                 } else if (secval) {
 241                                         for (i = 0; i < DEV_BSIZE; i++)
 242                                                 dst[i] = secval;
 243                                 } else {
 244                                         bzero(dst, DEV_BSIZE);
 245                                 }
 246                         } else {
 247                                 uc = dst[0];
 248                                 for (i = 1; i < DEV_BSIZE; i++)
 249                                         if (dst[i] != uc)
 250                                                 break;
 251                                 if (i == DEV_BSIZE && !uc) {
 252                                         if (secp)
 253                                                 FREE(secp, M_MDSECT);
 254                                         if (secpp)
 255                                                 *secpp = (u_char *)uc;
 256                                 } else {
 257                                         if (!secpp) {
 258                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK);
 259                                                 bzero(secpp, (secno + nsec + 1) * sizeof(u_char *));
 260                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 261                                                 FREE(sc->secp, M_MD);
 262                                                 sc->secp = secpp;
 263                                                 sc->nsecp = secno + nsec + 1;
 264                                                 secpp = &sc->secp[secno];
 265                                         }
 266                                         if (i == DEV_BSIZE) {
 267                                                 if (secp)
 268                                                         FREE(secp, M_MDSECT);
 269                                                 *secpp = (u_char *)uc;
 270                                         } else {
 271                                                 if (!secp)
 272                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 273                                                 bcopy(dst, secp, DEV_BSIZE);
 274
 275                                                 *secpp = secp;
 276                                         }
 277                                 }
 278                         }
 279                         secno++;
 280                         dst += DEV_BSIZE;
 281                 }
 282                 bp->b_resid = 0;
 283                 devstat_end_transaction_buf(&sc->stats, bp);
 284                 biodone(bp);
 285                 crit_enter();
 286         }
 287         sc->busy = 0;
 288         return;
 289 }
 290
 291
 292 static void
 293 mdstrategy_preload(struct buf *bp)
 294 {
 295         struct md_s *sc;
 296         devstat_trans_flags dop;
 297
 298         if (md_debug > 1)
 299                 printf("mdstrategy_preload(%p) %s %lx, %d, %ld, %p)\n",
 300                     bp, devtoname(bp->b_dev), bp->b_flags, bp->b_blkno,
 301                     bp->b_bcount / DEV_BSIZE, bp->b_data);
 302
 303         sc = bp->b_dev->si_drv1;
 304
 305         crit_enter();
 306
 307         bufqdisksort(&sc->buf_queue, bp);
 308
 309         if (sc->busy) {
 310                 crit_exit();
 311                 return;
 312         }
 313
 314         sc->busy++;
 315
 316         while (1) {
 317                 bp = bufq_first(&sc->buf_queue);
 318                 if (bp)
 319                         bufq_remove(&sc->buf_queue, bp);
 320                 crit_exit();
 321                 if (!bp)
 322                         break;
 323
 324                 devstat_start_transaction(&sc->stats);
 325
 326                 if (bp->b_flags & B_FREEBUF) {
 327                         dop = DEVSTAT_NO_DATA;
 328                 } else if (bp->b_flags & B_READ) {
 329                         dop = DEVSTAT_READ;
 330                         bcopy(sc->pl_ptr + (bp->b_pblkno << DEV_BSHIFT), bp->b_data, bp->b_bcount);
 331                 } else {
 332                         dop = DEVSTAT_WRITE;
 333                         bcopy(bp->b_data, sc->pl_ptr + (bp->b_pblkno << DEV_BSHIFT), bp->b_bcount);
 334                 }
 335                 bp->b_resid = 0;
 336                 devstat_end_transaction_buf(&sc->stats, bp);
 337                 biodone(bp);
 338                 crit_enter();
 339         }
 340         sc->busy = 0;
 341         return;
 342 }
 343
 344 static struct md_s *
 345 mdcreate(void)
 346 {
 347         struct md_s *sc;
 348
 349         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK);
 350         bzero(sc, sizeof(*sc));
 351         sc->unit = mdunits++;
 352         bufq_init(&sc->buf_queue);
 353         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 354                 DEVSTAT_NO_ORDERED_TAGS,
 355                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 356                 DEVSTAT_PRIORITY_OTHER);
 357         sc->dev = disk_create(sc->unit, &sc->disk, 0, &md_cdevsw);
 358         sc->dev->si_drv1 = sc;
 359         return (sc);
 360 }
 361
 362 static void
 363 mdcreate_preload(u_char *image, unsigned length)
 364 {
 365         struct md_s *sc;
 366
 367         sc = mdcreate();
 368         sc->type = MD_PRELOAD;
 369         sc->nsect = length / DEV_BSIZE;
 370         sc->pl_ptr = image;
 371         sc->pl_len = length;
 372
 373         if (sc->unit == 0)
 374                 mdrootready = 1;
 375 }
 376
 377 static void
 378 mdcreate_malloc(void)
 379 {
 380         struct md_s *sc;
 381
 382         sc = mdcreate();
 383         sc->type = MD_MALLOC;
 384
 385         sc->nsect = MD_NSECT;   /* for now */
 386         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK);
 387         bzero(sc->secp, sizeof(u_char *));
 388         sc->nsecp = 1;
 389         printf("md%d: Malloc disk\n", sc->unit);
 390 }
 391
 392 static void
 393 md_drvinit(void *unused)
 394 {
 395
 396         caddr_t mod;
 397         caddr_t c;
 398         u_char *ptr, *name, *type;
 399         unsigned len;
 400
 401 #ifdef MD_ROOT_SIZE
 402         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 403 #endif
 404         mod = NULL;
 405         while ((mod = preload_search_next_name(mod)) != NULL) {
 406                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 407                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 408                 if (name == NULL)
 409                         continue;
 410                 if (type == NULL)
 411                         continue;
 412                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 413                         continue;
 414                 c = preload_search_info(mod, MODINFO_ADDR);
 415                 ptr = *(u_char **)c;
 416                 c = preload_search_info(mod, MODINFO_SIZE);
 417                 len = *(unsigned *)c;
 418                 printf("md%d: Preloaded image <%s> %d bytes at %p\n",
 419                    mdunits, name, len, ptr);
 420                 mdcreate_preload(ptr, len);
 421         }
 422         mdcreate_malloc();
 423 }
 424
 425 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 426
 427 #ifdef MD_ROOT
 428 static void
 429 md_takeroot(void *junk)
 430 {
 431         if (mdrootready)
 432                 rootdevnames[0] = "ufs:/dev/md0c";
 433 }
 434
 435 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 436 #endif