Annotation of sys/ufs/ufs/ufs_dirhash.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: ufs_dirhash.c,v 1.15 2007/07/23 17:28:25 kettenis Exp $ */
! 2: /*
! 3: * Copyright (c) 2001, 2002 Ian Dowse. 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, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice, this list of conditions and the following disclaimer in the
! 12: * documentation and/or other materials provided with the distribution.
! 13: *
! 14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
! 15: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 16: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 17: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
! 18: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 19: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 20: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 21: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 22: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 23: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 24: * SUCH DAMAGE.
! 25: */
! 26:
! 27: /*
! 28: * This implements a hash-based lookup scheme for UFS directories.
! 29: */
! 30:
! 31: #if 0
! 32: __FBSDID("$FreeBSD: src/sys/ufs/ufs/ufs_dirhash.c,v 1.18 2004/02/15 21:39:35 dwmalone Exp $");
! 33: #endif
! 34:
! 35: #include <sys/param.h>
! 36: #include <sys/systm.h>
! 37: #include <sys/kernel.h>
! 38: #include <sys/lock.h>
! 39: #include <sys/rwlock.h>
! 40: #include <sys/malloc.h>
! 41: #include <sys/pool.h>
! 42: #include <sys/proc.h>
! 43: #include <sys/buf.h>
! 44: #include <sys/vnode.h>
! 45: #include <sys/mount.h>
! 46: #include <sys/sysctl.h>
! 47: #include <sys/hash.h>
! 48:
! 49: #include <ufs/ufs/quota.h>
! 50: #include <ufs/ufs/inode.h>
! 51: #include <ufs/ufs/dir.h>
! 52: #include <ufs/ufs/dirhash.h>
! 53: #include <ufs/ufs/ufsmount.h>
! 54: #include <ufs/ufs/ufs_extern.h>
! 55:
! 56: #define WRAPINCR(val, limit) (((val) + 1 == (limit)) ? 0 : ((val) + 1))
! 57: #define WRAPDECR(val, limit) (((val) == 0) ? ((limit) - 1) : ((val) - 1))
! 58: #define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0)
! 59: #define BLKFREE2IDX(n) ((n) > DH_NFSTATS ? DH_NFSTATS : (n))
! 60:
! 61: int ufs_mindirhashsize;
! 62: int ufs_dirhashmaxmem;
! 63: int ufs_dirhashmem;
! 64: int ufs_dirhashcheck;
! 65:
! 66:
! 67: int ufsdirhash_hash(struct dirhash *dh, char *name, int namelen);
! 68: void ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff);
! 69: void ufsdirhash_delslot(struct dirhash *dh, int slot);
! 70: int ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen,
! 71: doff_t offset);
! 72: doff_t ufsdirhash_getprev(struct direct *dp, doff_t offset);
! 73: int ufsdirhash_recycle(int wanted);
! 74:
! 75: struct pool ufsdirhash_pool;
! 76:
! 77: #define DIRHASHLIST_LOCK()
! 78: #define DIRHASHLIST_UNLOCK()
! 79: #define DIRHASH_LOCK(dh)
! 80: #define DIRHASH_UNLOCK(dh)
! 81: #define DIRHASH_BLKALLOC() pool_get(&ufsdirhash_pool, PR_NOWAIT)
! 82: #define DIRHASH_BLKFREE(v) pool_put(&ufsdirhash_pool, v)
! 83:
! 84: #define mtx_assert(l, f) /* nothing */
! 85: #define DIRHASH_ASSERT(e, m) KASSERT((e))
! 86:
! 87: /* Dirhash list; recently-used entries are near the tail. */
! 88: TAILQ_HEAD(, dirhash) ufsdirhash_list;
! 89:
! 90: /* Protects: ufsdirhash_list, `dh_list' field, ufs_dirhashmem. */
! 91:
! 92: /*
! 93: * Locking order:
! 94: * ufsdirhash_mtx
! 95: * dh_mtx
! 96: *
! 97: * The dh_mtx mutex should be acquired either via the inode lock, or via
! 98: * ufsdirhash_mtx. Only the owner of the inode may free the associated
! 99: * dirhash, but anything can steal its memory and set dh_hash to NULL.
! 100: */
! 101:
! 102: /*
! 103: * Attempt to build up a hash table for the directory contents in
! 104: * inode 'ip'. Returns 0 on success, or -1 of the operation failed.
! 105: */
! 106: int
! 107: ufsdirhash_build(struct inode *ip)
! 108: {
! 109: struct dirhash *dh;
! 110: struct buf *bp = NULL;
! 111: struct direct *ep;
! 112: struct vnode *vp;
! 113: doff_t bmask, pos;
! 114: int dirblocks, i, j, memreqd, nblocks, narrays, nslots, slot;
! 115:
! 116: /* Check if we can/should use dirhash. */
! 117: if (ip->i_dirhash == NULL) {
! 118: if (DIP(ip, size) < ufs_mindirhashsize || OFSFMT(ip->i_vnode))
! 119: return (-1);
! 120: } else {
! 121: /* Hash exists, but sysctls could have changed. */
! 122: if (DIP(ip, size) < ufs_mindirhashsize ||
! 123: ufs_dirhashmem > ufs_dirhashmaxmem) {
! 124: ufsdirhash_free(ip);
! 125: return (-1);
! 126: }
! 127: /* Check if hash exists and is intact (note: unlocked read). */
! 128: if (ip->i_dirhash->dh_hash != NULL)
! 129: return (0);
! 130: /* Free the old, recycled hash and build a new one. */
! 131: ufsdirhash_free(ip);
! 132: }
! 133:
! 134: /* Don't hash removed directories. */
! 135: if (ip->i_effnlink == 0)
! 136: return (-1);
! 137:
! 138: vp = ip->i_vnode;
! 139: /* Allocate 50% more entries than this dir size could ever need. */
! 140: DIRHASH_ASSERT(DIP(ip, size) >= DIRBLKSIZ, ("ufsdirhash_build size"));
! 141: nslots = DIP(ip, size) / DIRECTSIZ(1);
! 142: nslots = (nslots * 3 + 1) / 2;
! 143: narrays = howmany(nslots, DH_NBLKOFF);
! 144: nslots = narrays * DH_NBLKOFF;
! 145: dirblocks = howmany(DIP(ip, size), DIRBLKSIZ);
! 146: nblocks = (dirblocks * 3 + 1) / 2;
! 147:
! 148: memreqd = sizeof(*dh) + narrays * sizeof(*dh->dh_hash) +
! 149: narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) +
! 150: nblocks * sizeof(*dh->dh_blkfree);
! 151: DIRHASHLIST_LOCK();
! 152: if (memreqd + ufs_dirhashmem > ufs_dirhashmaxmem) {
! 153: DIRHASHLIST_UNLOCK();
! 154: if (memreqd > ufs_dirhashmaxmem / 2)
! 155: return (-1);
! 156:
! 157: /* Try to free some space. */
! 158: if (ufsdirhash_recycle(memreqd) != 0)
! 159: return (-1);
! 160: /* Enough was freed, and list has been locked. */
! 161: }
! 162: ufs_dirhashmem += memreqd;
! 163: DIRHASHLIST_UNLOCK();
! 164:
! 165: /*
! 166: * Use non-blocking mallocs so that we will revert to a linear
! 167: * lookup on failure rather than potentially blocking forever.
! 168: */
! 169: MALLOC(dh, struct dirhash *, sizeof *dh, M_DIRHASH, M_NOWAIT);
! 170: if (dh == NULL) {
! 171: DIRHASHLIST_LOCK();
! 172: ufs_dirhashmem -= memreqd;
! 173: DIRHASHLIST_UNLOCK();
! 174: return (-1);
! 175: }
! 176: memset(dh, 0, sizeof *dh);
! 177: dh->dh_hash = malloc(narrays * sizeof(dh->dh_hash[0]),
! 178: M_DIRHASH, M_NOWAIT);
! 179: dh->dh_blkfree = malloc(nblocks * sizeof(dh->dh_blkfree[0]),
! 180: M_DIRHASH, M_NOWAIT);
! 181: if (dh->dh_hash == NULL || dh->dh_blkfree == NULL)
! 182: goto fail;
! 183: memset(dh->dh_hash, 0, narrays * sizeof(dh->dh_hash[0]));
! 184: for (i = 0; i < narrays; i++) {
! 185: if ((dh->dh_hash[i] = DIRHASH_BLKALLOC()) == NULL)
! 186: goto fail;
! 187: for (j = 0; j < DH_NBLKOFF; j++)
! 188: dh->dh_hash[i][j] = DIRHASH_EMPTY;
! 189: }
! 190:
! 191: /* Initialise the hash table and block statistics. */
! 192: dh->dh_narrays = narrays;
! 193: dh->dh_hlen = nslots;
! 194: dh->dh_nblk = nblocks;
! 195: dh->dh_dirblks = dirblocks;
! 196: for (i = 0; i < dirblocks; i++)
! 197: dh->dh_blkfree[i] = DIRBLKSIZ / DIRALIGN;
! 198: for (i = 0; i < DH_NFSTATS; i++)
! 199: dh->dh_firstfree[i] = -1;
! 200: dh->dh_firstfree[DH_NFSTATS] = 0;
! 201: dh->dh_seqopt = 0;
! 202: dh->dh_seqoff = 0;
! 203: dh->dh_score = DH_SCOREINIT;
! 204: ip->i_dirhash = dh;
! 205:
! 206: bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
! 207: pos = 0;
! 208: while (pos < DIP(ip, size)) {
! 209: /* If necessary, get the next directory block. */
! 210: if ((pos & bmask) == 0) {
! 211: if (bp != NULL)
! 212: brelse(bp);
! 213: if (UFS_BUFATOFF(ip, (off_t)pos, NULL, &bp) != 0)
! 214: goto fail;
! 215: }
! 216:
! 217: /* Add this entry to the hash. */
! 218: ep = (struct direct *)((char *)bp->b_data + (pos & bmask));
! 219: if (ep->d_reclen == 0 || ep->d_reclen >
! 220: DIRBLKSIZ - (pos & (DIRBLKSIZ - 1))) {
! 221: /* Corrupted directory. */
! 222: brelse(bp);
! 223: goto fail;
! 224: }
! 225: if (ep->d_ino != 0) {
! 226: /* Add the entry (simplified ufsdirhash_add). */
! 227: slot = ufsdirhash_hash(dh, ep->d_name, ep->d_namlen);
! 228: while (DH_ENTRY(dh, slot) != DIRHASH_EMPTY)
! 229: slot = WRAPINCR(slot, dh->dh_hlen);
! 230: dh->dh_hused++;
! 231: DH_ENTRY(dh, slot) = pos;
! 232: ufsdirhash_adjfree(dh, pos, -DIRSIZ(0, ep));
! 233: }
! 234: pos += ep->d_reclen;
! 235: }
! 236:
! 237: if (bp != NULL)
! 238: brelse(bp);
! 239: DIRHASHLIST_LOCK();
! 240: TAILQ_INSERT_TAIL(&ufsdirhash_list, dh, dh_list);
! 241: dh->dh_onlist = 1;
! 242: DIRHASHLIST_UNLOCK();
! 243: return (0);
! 244:
! 245: fail:
! 246: if (dh->dh_hash != NULL) {
! 247: for (i = 0; i < narrays; i++)
! 248: if (dh->dh_hash[i] != NULL)
! 249: DIRHASH_BLKFREE(dh->dh_hash[i]);
! 250: free(dh->dh_hash, M_DIRHASH);
! 251: }
! 252: if (dh->dh_blkfree != NULL)
! 253: free(dh->dh_blkfree, M_DIRHASH);
! 254: FREE(dh, M_DIRHASH);
! 255: ip->i_dirhash = NULL;
! 256: DIRHASHLIST_LOCK();
! 257: ufs_dirhashmem -= memreqd;
! 258: DIRHASHLIST_UNLOCK();
! 259: return (-1);
! 260: }
! 261:
! 262: /*
! 263: * Free any hash table associated with inode 'ip'.
! 264: */
! 265: void
! 266: ufsdirhash_free(struct inode *ip)
! 267: {
! 268: struct dirhash *dh;
! 269: int i, mem;
! 270:
! 271: if ((dh = ip->i_dirhash) == NULL)
! 272: return;
! 273: DIRHASHLIST_LOCK();
! 274: DIRHASH_LOCK(dh);
! 275: if (dh->dh_onlist)
! 276: TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
! 277: DIRHASH_UNLOCK(dh);
! 278: DIRHASHLIST_UNLOCK();
! 279:
! 280: /* The dirhash pointed to by 'dh' is exclusively ours now. */
! 281:
! 282: mem = sizeof(*dh);
! 283: if (dh->dh_hash != NULL) {
! 284: for (i = 0; i < dh->dh_narrays; i++)
! 285: DIRHASH_BLKFREE(dh->dh_hash[i]);
! 286: free(dh->dh_hash, M_DIRHASH);
! 287: free(dh->dh_blkfree, M_DIRHASH);
! 288: mem += dh->dh_narrays * sizeof(*dh->dh_hash) +
! 289: dh->dh_narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) +
! 290: dh->dh_nblk * sizeof(*dh->dh_blkfree);
! 291: }
! 292: FREE(dh, M_DIRHASH);
! 293: ip->i_dirhash = NULL;
! 294:
! 295: DIRHASHLIST_LOCK();
! 296: ufs_dirhashmem -= mem;
! 297: DIRHASHLIST_UNLOCK();
! 298: }
! 299:
! 300: /*
! 301: * Find the offset of the specified name within the given inode.
! 302: * Returns 0 on success, ENOENT if the entry does not exist, or
! 303: * EJUSTRETURN if the caller should revert to a linear search.
! 304: *
! 305: * If successful, the directory offset is stored in *offp, and a
! 306: * pointer to a struct buf containing the entry is stored in *bpp. If
! 307: * prevoffp is non-NULL, the offset of the previous entry within
! 308: * the DIRBLKSIZ-sized block is stored in *prevoffp (if the entry
! 309: * is the first in a block, the start of the block is used).
! 310: */
! 311: int
! 312: ufsdirhash_lookup(struct inode *ip, char *name, int namelen, doff_t *offp,
! 313: struct buf **bpp, doff_t *prevoffp)
! 314: {
! 315: struct dirhash *dh, *dh_next;
! 316: struct direct *dp;
! 317: struct vnode *vp;
! 318: struct buf *bp;
! 319: doff_t blkoff, bmask, offset, prevoff;
! 320: int i, slot;
! 321:
! 322: if ((dh = ip->i_dirhash) == NULL)
! 323: return (EJUSTRETURN);
! 324: /*
! 325: * Move this dirhash towards the end of the list if it has a
! 326: * score higher than the next entry, and acquire the dh_mtx.
! 327: * Optimise the case where it's already the last by performing
! 328: * an unlocked read of the TAILQ_NEXT pointer.
! 329: *
! 330: * In both cases, end up holding just dh_mtx.
! 331: */
! 332: if (TAILQ_NEXT(dh, dh_list) != NULL) {
! 333: DIRHASHLIST_LOCK();
! 334: DIRHASH_LOCK(dh);
! 335: /*
! 336: * If the new score will be greater than that of the next
! 337: * entry, then move this entry past it. With both mutexes
! 338: * held, dh_next won't go away, but its dh_score could
! 339: * change; that's not important since it is just a hint.
! 340: */
! 341: if (dh->dh_hash != NULL &&
! 342: (dh_next = TAILQ_NEXT(dh, dh_list)) != NULL &&
! 343: dh->dh_score >= dh_next->dh_score) {
! 344: DIRHASH_ASSERT(dh->dh_onlist, ("dirhash: not on list"));
! 345: TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
! 346: TAILQ_INSERT_AFTER(&ufsdirhash_list, dh_next, dh,
! 347: dh_list);
! 348: }
! 349: DIRHASHLIST_UNLOCK();
! 350: } else {
! 351: /* Already the last, though that could change as we wait. */
! 352: DIRHASH_LOCK(dh);
! 353: }
! 354: if (dh->dh_hash == NULL) {
! 355: DIRHASH_UNLOCK(dh);
! 356: ufsdirhash_free(ip);
! 357: return (EJUSTRETURN);
! 358: }
! 359:
! 360: /* Update the score. */
! 361: if (dh->dh_score < DH_SCOREMAX)
! 362: dh->dh_score++;
! 363:
! 364: vp = ip->i_vnode;
! 365: bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
! 366: blkoff = -1;
! 367: bp = NULL;
! 368: restart:
! 369: slot = ufsdirhash_hash(dh, name, namelen);
! 370:
! 371: if (dh->dh_seqopt) {
! 372: /*
! 373: * Sequential access optimisation. dh_seqoff contains the
! 374: * offset of the directory entry immediately following
! 375: * the last entry that was looked up. Check if this offset
! 376: * appears in the hash chain for the name we are looking for.
! 377: */
! 378: for (i = slot; (offset = DH_ENTRY(dh, i)) != DIRHASH_EMPTY;
! 379: i = WRAPINCR(i, dh->dh_hlen))
! 380: if (offset == dh->dh_seqoff)
! 381: break;
! 382: if (offset == dh->dh_seqoff) {
! 383: /*
! 384: * We found an entry with the expected offset. This
! 385: * is probably the entry we want, but if not, the
! 386: * code below will turn off seqoff and retry.
! 387: */
! 388: slot = i;
! 389: } else
! 390: dh->dh_seqopt = 0;
! 391: }
! 392:
! 393: for (; (offset = DH_ENTRY(dh, slot)) != DIRHASH_EMPTY;
! 394: slot = WRAPINCR(slot, dh->dh_hlen)) {
! 395: if (offset == DIRHASH_DEL)
! 396: continue;
! 397: DIRHASH_UNLOCK(dh);
! 398:
! 399: if (offset < 0 || offset >= DIP(ip, size))
! 400: panic("ufsdirhash_lookup: bad offset in hash array");
! 401: if ((offset & ~bmask) != blkoff) {
! 402: if (bp != NULL)
! 403: brelse(bp);
! 404: blkoff = offset & ~bmask;
! 405: if (UFS_BUFATOFF(ip, (off_t)blkoff, NULL, &bp) != 0)
! 406: return (EJUSTRETURN);
! 407: }
! 408: dp = (struct direct *)(bp->b_data + (offset & bmask));
! 409: if (dp->d_reclen == 0 || dp->d_reclen >
! 410: DIRBLKSIZ - (offset & (DIRBLKSIZ - 1))) {
! 411: /* Corrupted directory. */
! 412: brelse(bp);
! 413: return (EJUSTRETURN);
! 414: }
! 415: if (dp->d_namlen == namelen &&
! 416: bcmp(dp->d_name, name, namelen) == 0) {
! 417: /* Found. Get the prev offset if needed. */
! 418: if (prevoffp != NULL) {
! 419: if (offset & (DIRBLKSIZ - 1)) {
! 420: prevoff = ufsdirhash_getprev(dp,
! 421: offset);
! 422: if (prevoff == -1) {
! 423: brelse(bp);
! 424: return (EJUSTRETURN);
! 425: }
! 426: } else
! 427: prevoff = offset;
! 428: *prevoffp = prevoff;
! 429: }
! 430:
! 431: /* Check for sequential access, and update offset. */
! 432: if (dh->dh_seqopt == 0 && dh->dh_seqoff == offset)
! 433: dh->dh_seqopt = 1;
! 434: dh->dh_seqoff = offset + DIRSIZ(0, dp);
! 435:
! 436: *bpp = bp;
! 437: *offp = offset;
! 438: return (0);
! 439: }
! 440:
! 441: DIRHASH_LOCK(dh);
! 442: if (dh->dh_hash == NULL) {
! 443: DIRHASH_UNLOCK(dh);
! 444: if (bp != NULL)
! 445: brelse(bp);
! 446: ufsdirhash_free(ip);
! 447: return (EJUSTRETURN);
! 448: }
! 449: /*
! 450: * When the name doesn't match in the seqopt case, go back
! 451: * and search normally.
! 452: */
! 453: if (dh->dh_seqopt) {
! 454: dh->dh_seqopt = 0;
! 455: goto restart;
! 456: }
! 457: }
! 458: DIRHASH_UNLOCK(dh);
! 459: if (bp != NULL)
! 460: brelse(bp);
! 461: return (ENOENT);
! 462: }
! 463:
! 464: /*
! 465: * Find a directory block with room for 'slotneeded' bytes. Returns
! 466: * the offset of the directory entry that begins the free space.
! 467: * This will either be the offset of an existing entry that has free
! 468: * space at the end, or the offset of an entry with d_ino == 0 at
! 469: * the start of a DIRBLKSIZ block.
! 470: *
! 471: * To use the space, the caller may need to compact existing entries in
! 472: * the directory. The total number of bytes in all of the entries involved
! 473: * in the compaction is stored in *slotsize. In other words, all of
! 474: * the entries that must be compacted are exactly contained in the
! 475: * region beginning at the returned offset and spanning *slotsize bytes.
! 476: *
! 477: * Returns -1 if no space was found, indicating that the directory
! 478: * must be extended.
! 479: */
! 480: doff_t
! 481: ufsdirhash_findfree(struct inode *ip, int slotneeded, int *slotsize)
! 482: {
! 483: struct direct *dp;
! 484: struct dirhash *dh;
! 485: struct buf *bp;
! 486: doff_t pos, slotstart;
! 487: int dirblock, error, freebytes, i;
! 488:
! 489: if ((dh = ip->i_dirhash) == NULL)
! 490: return (-1);
! 491: DIRHASH_LOCK(dh);
! 492: if (dh->dh_hash == NULL) {
! 493: DIRHASH_UNLOCK(dh);
! 494: ufsdirhash_free(ip);
! 495: return (-1);
! 496: }
! 497:
! 498: /* Find a directory block with the desired free space. */
! 499: dirblock = -1;
! 500: for (i = howmany(slotneeded, DIRALIGN); i <= DH_NFSTATS; i++)
! 501: if ((dirblock = dh->dh_firstfree[i]) != -1)
! 502: break;
! 503: if (dirblock == -1) {
! 504: DIRHASH_UNLOCK(dh);
! 505: return (-1);
! 506: }
! 507:
! 508: DIRHASH_ASSERT(dirblock < dh->dh_nblk &&
! 509: dh->dh_blkfree[dirblock] >= howmany(slotneeded, DIRALIGN),
! 510: ("ufsdirhash_findfree: bad stats"));
! 511: DIRHASH_UNLOCK(dh);
! 512: pos = dirblock * DIRBLKSIZ;
! 513: error = UFS_BUFATOFF(ip, (off_t)pos, (char **)&dp, &bp);
! 514: if (error)
! 515: return (-1);
! 516:
! 517: /* Find the first entry with free space. */
! 518: for (i = 0; i < DIRBLKSIZ; ) {
! 519: if (dp->d_reclen == 0) {
! 520: brelse(bp);
! 521: return (-1);
! 522: }
! 523: if (dp->d_ino == 0 || dp->d_reclen > DIRSIZ(0, dp))
! 524: break;
! 525: i += dp->d_reclen;
! 526: dp = (struct direct *)((char *)dp + dp->d_reclen);
! 527: }
! 528: if (i > DIRBLKSIZ) {
! 529: brelse(bp);
! 530: return (-1);
! 531: }
! 532: slotstart = pos + i;
! 533:
! 534: /* Find the range of entries needed to get enough space */
! 535: freebytes = 0;
! 536: while (i < DIRBLKSIZ && freebytes < slotneeded) {
! 537: freebytes += dp->d_reclen;
! 538: if (dp->d_ino != 0)
! 539: freebytes -= DIRSIZ(0, dp);
! 540: if (dp->d_reclen == 0) {
! 541: brelse(bp);
! 542: return (-1);
! 543: }
! 544: i += dp->d_reclen;
! 545: dp = (struct direct *)((char *)dp + dp->d_reclen);
! 546: }
! 547: if (i > DIRBLKSIZ) {
! 548: brelse(bp);
! 549: return (-1);
! 550: }
! 551: if (freebytes < slotneeded)
! 552: panic("ufsdirhash_findfree: free mismatch");
! 553: brelse(bp);
! 554: *slotsize = pos + i - slotstart;
! 555: return (slotstart);
! 556: }
! 557:
! 558: /*
! 559: * Return the start of the unused space at the end of a directory, or
! 560: * -1 if there are no trailing unused blocks.
! 561: */
! 562: doff_t
! 563: ufsdirhash_enduseful(struct inode *ip)
! 564: {
! 565:
! 566: struct dirhash *dh;
! 567: int i;
! 568:
! 569: if ((dh = ip->i_dirhash) == NULL)
! 570: return (-1);
! 571: DIRHASH_LOCK(dh);
! 572: if (dh->dh_hash == NULL) {
! 573: DIRHASH_UNLOCK(dh);
! 574: ufsdirhash_free(ip);
! 575: return (-1);
! 576: }
! 577:
! 578: if (dh->dh_blkfree[dh->dh_dirblks - 1] != DIRBLKSIZ / DIRALIGN) {
! 579: DIRHASH_UNLOCK(dh);
! 580: return (-1);
! 581: }
! 582:
! 583: for (i = dh->dh_dirblks - 1; i >= 0; i--)
! 584: if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN)
! 585: break;
! 586: DIRHASH_UNLOCK(dh);
! 587: return ((doff_t)(i + 1) * DIRBLKSIZ);
! 588: }
! 589:
! 590: /*
! 591: * Insert information into the hash about a new directory entry. dirp
! 592: * points to a struct direct containing the entry, and offset specifies
! 593: * the offset of this entry.
! 594: */
! 595: void
! 596: ufsdirhash_add(struct inode *ip, struct direct *dirp, doff_t offset)
! 597: {
! 598: struct dirhash *dh;
! 599: int slot;
! 600:
! 601: if ((dh = ip->i_dirhash) == NULL)
! 602: return;
! 603: DIRHASH_LOCK(dh);
! 604: if (dh->dh_hash == NULL) {
! 605: DIRHASH_UNLOCK(dh);
! 606: ufsdirhash_free(ip);
! 607: return;
! 608: }
! 609:
! 610: DIRHASH_ASSERT(offset < dh->dh_dirblks * DIRBLKSIZ,
! 611: ("ufsdirhash_add: bad offset"));
! 612: /*
! 613: * Normal hash usage is < 66%. If the usage gets too high then
! 614: * remove the hash entirely and let it be rebuilt later.
! 615: */
! 616: if (dh->dh_hused >= (dh->dh_hlen * 3) / 4) {
! 617: DIRHASH_UNLOCK(dh);
! 618: ufsdirhash_free(ip);
! 619: return;
! 620: }
! 621:
! 622: /* Find a free hash slot (empty or deleted), and add the entry. */
! 623: slot = ufsdirhash_hash(dh, dirp->d_name, dirp->d_namlen);
! 624: while (DH_ENTRY(dh, slot) >= 0)
! 625: slot = WRAPINCR(slot, dh->dh_hlen);
! 626: if (DH_ENTRY(dh, slot) == DIRHASH_EMPTY)
! 627: dh->dh_hused++;
! 628: DH_ENTRY(dh, slot) = offset;
! 629:
! 630: /* Update the per-block summary info. */
! 631: ufsdirhash_adjfree(dh, offset, -DIRSIZ(0, dirp));
! 632: DIRHASH_UNLOCK(dh);
! 633: }
! 634:
! 635: /*
! 636: * Remove the specified directory entry from the hash. The entry to remove
! 637: * is defined by the name in `dirp', which must exist at the specified
! 638: * `offset' within the directory.
! 639: */
! 640: void
! 641: ufsdirhash_remove(struct inode *ip, struct direct *dirp, doff_t offset)
! 642: {
! 643: struct dirhash *dh;
! 644: int slot;
! 645:
! 646: if ((dh = ip->i_dirhash) == NULL)
! 647: return;
! 648: DIRHASH_LOCK(dh);
! 649: if (dh->dh_hash == NULL) {
! 650: DIRHASH_UNLOCK(dh);
! 651: ufsdirhash_free(ip);
! 652: return;
! 653: }
! 654:
! 655: DIRHASH_ASSERT(offset < dh->dh_dirblks * DIRBLKSIZ,
! 656: ("ufsdirhash_remove: bad offset"));
! 657: /* Find the entry */
! 658: slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, offset);
! 659:
! 660: /* Remove the hash entry. */
! 661: ufsdirhash_delslot(dh, slot);
! 662:
! 663: /* Update the per-block summary info. */
! 664: ufsdirhash_adjfree(dh, offset, DIRSIZ(0, dirp));
! 665: DIRHASH_UNLOCK(dh);
! 666: }
! 667:
! 668: /*
! 669: * Change the offset associated with a directory entry in the hash. Used
! 670: * when compacting directory blocks.
! 671: */
! 672: void
! 673: ufsdirhash_move(struct inode *ip, struct direct *dirp, doff_t oldoff,
! 674: doff_t newoff)
! 675: {
! 676: struct dirhash *dh;
! 677: int slot;
! 678:
! 679: if ((dh = ip->i_dirhash) == NULL)
! 680: return;
! 681: DIRHASH_LOCK(dh);
! 682: if (dh->dh_hash == NULL) {
! 683: DIRHASH_UNLOCK(dh);
! 684: ufsdirhash_free(ip);
! 685: return;
! 686: }
! 687:
! 688: DIRHASH_ASSERT(oldoff < dh->dh_dirblks * DIRBLKSIZ &&
! 689: newoff < dh->dh_dirblks * DIRBLKSIZ,
! 690: ("ufsdirhash_move: bad offset"));
! 691: /* Find the entry, and update the offset. */
! 692: slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, oldoff);
! 693: DH_ENTRY(dh, slot) = newoff;
! 694: DIRHASH_UNLOCK(dh);
! 695: }
! 696:
! 697: /*
! 698: * Inform dirhash that the directory has grown by one block that
! 699: * begins at offset (i.e. the new length is offset + DIRBLKSIZ).
! 700: */
! 701: void
! 702: ufsdirhash_newblk(struct inode *ip, doff_t offset)
! 703: {
! 704: struct dirhash *dh;
! 705: int block;
! 706:
! 707: if ((dh = ip->i_dirhash) == NULL)
! 708: return;
! 709: DIRHASH_LOCK(dh);
! 710: if (dh->dh_hash == NULL) {
! 711: DIRHASH_UNLOCK(dh);
! 712: ufsdirhash_free(ip);
! 713: return;
! 714: }
! 715:
! 716: DIRHASH_ASSERT(offset == dh->dh_dirblks * DIRBLKSIZ,
! 717: ("ufsdirhash_newblk: bad offset"));
! 718: block = offset / DIRBLKSIZ;
! 719: if (block >= dh->dh_nblk) {
! 720: /* Out of space; must rebuild. */
! 721: DIRHASH_UNLOCK(dh);
! 722: ufsdirhash_free(ip);
! 723: return;
! 724: }
! 725: dh->dh_dirblks = block + 1;
! 726:
! 727: /* Account for the new free block. */
! 728: dh->dh_blkfree[block] = DIRBLKSIZ / DIRALIGN;
! 729: if (dh->dh_firstfree[DH_NFSTATS] == -1)
! 730: dh->dh_firstfree[DH_NFSTATS] = block;
! 731: DIRHASH_UNLOCK(dh);
! 732: }
! 733:
! 734: /*
! 735: * Inform dirhash that the directory is being truncated.
! 736: */
! 737: void
! 738: ufsdirhash_dirtrunc(struct inode *ip, doff_t offset)
! 739: {
! 740: struct dirhash *dh;
! 741: int block, i;
! 742:
! 743: if ((dh = ip->i_dirhash) == NULL)
! 744: return;
! 745: DIRHASH_LOCK(dh);
! 746: if (dh->dh_hash == NULL) {
! 747: DIRHASH_UNLOCK(dh);
! 748: ufsdirhash_free(ip);
! 749: return;
! 750: }
! 751:
! 752: DIRHASH_ASSERT(offset <= dh->dh_dirblks * DIRBLKSIZ,
! 753: ("ufsdirhash_dirtrunc: bad offset"));
! 754: block = howmany(offset, DIRBLKSIZ);
! 755: /*
! 756: * If the directory shrinks to less than 1/8 of dh_nblk blocks
! 757: * (about 20% of its original size due to the 50% extra added in
! 758: * ufsdirhash_build) then free it, and let the caller rebuild
! 759: * if necessary.
! 760: */
! 761: if (block < dh->dh_nblk / 8 && dh->dh_narrays > 1) {
! 762: DIRHASH_UNLOCK(dh);
! 763: ufsdirhash_free(ip);
! 764: return;
! 765: }
! 766:
! 767: /*
! 768: * Remove any `first free' information pertaining to the
! 769: * truncated blocks. All blocks we're removing should be
! 770: * completely unused.
! 771: */
! 772: if (dh->dh_firstfree[DH_NFSTATS] >= block)
! 773: dh->dh_firstfree[DH_NFSTATS] = -1;
! 774: for (i = block; i < dh->dh_dirblks; i++)
! 775: if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN)
! 776: panic("ufsdirhash_dirtrunc: blocks in use");
! 777: for (i = 0; i < DH_NFSTATS; i++)
! 778: if (dh->dh_firstfree[i] >= block)
! 779: panic("ufsdirhash_dirtrunc: first free corrupt");
! 780: dh->dh_dirblks = block;
! 781: DIRHASH_UNLOCK(dh);
! 782: }
! 783:
! 784: /*
! 785: * Debugging function to check that the dirhash information about
! 786: * a directory block matches its actual contents. Panics if a mismatch
! 787: * is detected.
! 788: *
! 789: * On entry, `buf' should point to the start of an in-core
! 790: * DIRBLKSIZ-sized directory block, and `offset' should contain the
! 791: * offset from the start of the directory of that block.
! 792: */
! 793: void
! 794: ufsdirhash_checkblock(struct inode *ip, char *buf, doff_t offset)
! 795: {
! 796: struct dirhash *dh;
! 797: struct direct *dp;
! 798: int block, ffslot, i, nfree;
! 799:
! 800: if (!ufs_dirhashcheck)
! 801: return;
! 802: if ((dh = ip->i_dirhash) == NULL)
! 803: return;
! 804: DIRHASH_LOCK(dh);
! 805: if (dh->dh_hash == NULL) {
! 806: DIRHASH_UNLOCK(dh);
! 807: ufsdirhash_free(ip);
! 808: return;
! 809: }
! 810:
! 811: block = offset / DIRBLKSIZ;
! 812: if ((offset & (DIRBLKSIZ - 1)) != 0 || block >= dh->dh_dirblks)
! 813: panic("ufsdirhash_checkblock: bad offset");
! 814:
! 815: nfree = 0;
! 816: for (i = 0; i < DIRBLKSIZ; i += dp->d_reclen) {
! 817: dp = (struct direct *)(buf + i);
! 818: if (dp->d_reclen == 0 || i + dp->d_reclen > DIRBLKSIZ)
! 819: panic("ufsdirhash_checkblock: bad dir");
! 820:
! 821: if (dp->d_ino == 0) {
! 822: #if 0
! 823: /*
! 824: * XXX entries with d_ino == 0 should only occur
! 825: * at the start of a DIRBLKSIZ block. However the
! 826: * ufs code is tolerant of such entries at other
! 827: * offsets, and fsck does not fix them.
! 828: */
! 829: if (i != 0)
! 830: panic("ufsdirhash_checkblock: bad dir inode");
! 831: #endif
! 832: nfree += dp->d_reclen;
! 833: continue;
! 834: }
! 835:
! 836: /* Check that the entry exists (will panic if it doesn't). */
! 837: ufsdirhash_findslot(dh, dp->d_name, dp->d_namlen, offset + i);
! 838:
! 839: nfree += dp->d_reclen - DIRSIZ(0, dp);
! 840: }
! 841: if (i != DIRBLKSIZ)
! 842: panic("ufsdirhash_checkblock: bad dir end");
! 843:
! 844: if (dh->dh_blkfree[block] * DIRALIGN != nfree)
! 845: panic("ufsdirhash_checkblock: bad free count");
! 846:
! 847: ffslot = BLKFREE2IDX(nfree / DIRALIGN);
! 848: for (i = 0; i <= DH_NFSTATS; i++)
! 849: if (dh->dh_firstfree[i] == block && i != ffslot)
! 850: panic("ufsdirhash_checkblock: bad first-free");
! 851: if (dh->dh_firstfree[ffslot] == -1)
! 852: panic("ufsdirhash_checkblock: missing first-free entry");
! 853: DIRHASH_UNLOCK(dh);
! 854: }
! 855:
! 856: /*
! 857: * Hash the specified filename into a dirhash slot.
! 858: */
! 859: int
! 860: ufsdirhash_hash(struct dirhash *dh, char *name, int namelen)
! 861: {
! 862: u_int32_t hash;
! 863:
! 864: /*
! 865: * We hash the name and then some other bit of data that is
! 866: * invariant over the dirhash's lifetime. Otherwise names
! 867: * differing only in the last byte are placed close to one
! 868: * another in the table, which is bad for linear probing.
! 869: */
! 870: hash = hash32_buf(name, namelen, HASHINIT);
! 871: hash = hash32_buf(&dh, sizeof(dh), hash);
! 872: return (hash % dh->dh_hlen);
! 873: }
! 874:
! 875: /*
! 876: * Adjust the number of free bytes in the block containing `offset'
! 877: * by the value specified by `diff'.
! 878: *
! 879: * The caller must ensure we have exclusive access to `dh'; normally
! 880: * that means that dh_mtx should be held, but this is also called
! 881: * from ufsdirhash_build() where exclusive access can be assumed.
! 882: */
! 883: void
! 884: ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff)
! 885: {
! 886: int block, i, nfidx, ofidx;
! 887:
! 888: /* Update the per-block summary info. */
! 889: block = offset / DIRBLKSIZ;
! 890: DIRHASH_ASSERT(block < dh->dh_nblk && block < dh->dh_dirblks,
! 891: ("dirhash bad offset"));
! 892: ofidx = BLKFREE2IDX(dh->dh_blkfree[block]);
! 893: dh->dh_blkfree[block] = (int)dh->dh_blkfree[block] + (diff / DIRALIGN);
! 894: nfidx = BLKFREE2IDX(dh->dh_blkfree[block]);
! 895:
! 896: /* Update the `first free' list if necessary. */
! 897: if (ofidx != nfidx) {
! 898: /* If removing, scan forward for the next block. */
! 899: if (dh->dh_firstfree[ofidx] == block) {
! 900: for (i = block + 1; i < dh->dh_dirblks; i++)
! 901: if (BLKFREE2IDX(dh->dh_blkfree[i]) == ofidx)
! 902: break;
! 903: dh->dh_firstfree[ofidx] = (i < dh->dh_dirblks) ? i : -1;
! 904: }
! 905:
! 906: /* Make this the new `first free' if necessary */
! 907: if (dh->dh_firstfree[nfidx] > block ||
! 908: dh->dh_firstfree[nfidx] == -1)
! 909: dh->dh_firstfree[nfidx] = block;
! 910: }
! 911: }
! 912:
! 913: /*
! 914: * Find the specified name which should have the specified offset.
! 915: * Returns a slot number, and panics on failure.
! 916: *
! 917: * `dh' must be locked on entry and remains so on return.
! 918: */
! 919: int
! 920: ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, doff_t offset)
! 921: {
! 922: int slot;
! 923:
! 924: mtx_assert(&dh->dh_mtx, MA_OWNED);
! 925:
! 926: /* Find the entry. */
! 927: DIRHASH_ASSERT(dh->dh_hused < dh->dh_hlen, ("dirhash find full"));
! 928: slot = ufsdirhash_hash(dh, name, namelen);
! 929: while (DH_ENTRY(dh, slot) != offset &&
! 930: DH_ENTRY(dh, slot) != DIRHASH_EMPTY)
! 931: slot = WRAPINCR(slot, dh->dh_hlen);
! 932: if (DH_ENTRY(dh, slot) != offset)
! 933: panic("ufsdirhash_findslot: '%.*s' not found", namelen, name);
! 934:
! 935: return (slot);
! 936: }
! 937:
! 938: /*
! 939: * Remove the entry corresponding to the specified slot from the hash array.
! 940: *
! 941: * `dh' must be locked on entry and remains so on return.
! 942: */
! 943: void
! 944: ufsdirhash_delslot(struct dirhash *dh, int slot)
! 945: {
! 946: int i;
! 947:
! 948: mtx_assert(&dh->dh_mtx, MA_OWNED);
! 949:
! 950: /* Mark the entry as deleted. */
! 951: DH_ENTRY(dh, slot) = DIRHASH_DEL;
! 952:
! 953: /* If this is the end of a chain of DIRHASH_DEL slots, remove them. */
! 954: for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; )
! 955: i = WRAPINCR(i, dh->dh_hlen);
! 956: if (DH_ENTRY(dh, i) == DIRHASH_EMPTY) {
! 957: i = WRAPDECR(i, dh->dh_hlen);
! 958: while (DH_ENTRY(dh, i) == DIRHASH_DEL) {
! 959: DH_ENTRY(dh, i) = DIRHASH_EMPTY;
! 960: dh->dh_hused--;
! 961: i = WRAPDECR(i, dh->dh_hlen);
! 962: }
! 963: DIRHASH_ASSERT(dh->dh_hused >= 0, ("ufsdirhash_delslot neg hlen"));
! 964: }
! 965: }
! 966:
! 967: /*
! 968: * Given a directory entry and its offset, find the offset of the
! 969: * previous entry in the same DIRBLKSIZ-sized block. Returns an
! 970: * offset, or -1 if there is no previous entry in the block or some
! 971: * other problem occurred.
! 972: */
! 973: doff_t
! 974: ufsdirhash_getprev(struct direct *dirp, doff_t offset)
! 975: {
! 976: struct direct *dp;
! 977: char *blkbuf;
! 978: doff_t blkoff, prevoff;
! 979: int entrypos, i;
! 980:
! 981: blkoff = offset & ~(DIRBLKSIZ - 1); /* offset of start of block */
! 982: entrypos = offset & (DIRBLKSIZ - 1); /* entry relative to block */
! 983: blkbuf = (char *)dirp - entrypos;
! 984: prevoff = blkoff;
! 985:
! 986: /* If `offset' is the start of a block, there is no previous entry. */
! 987: if (entrypos == 0)
! 988: return (-1);
! 989:
! 990: /* Scan from the start of the block until we get to the entry. */
! 991: for (i = 0; i < entrypos; i += dp->d_reclen) {
! 992: dp = (struct direct *)(blkbuf + i);
! 993: if (dp->d_reclen == 0 || i + dp->d_reclen > entrypos)
! 994: return (-1); /* Corrupted directory. */
! 995: prevoff = blkoff + i;
! 996: }
! 997: return (prevoff);
! 998: }
! 999:
! 1000: /*
! 1001: * Try to free up `wanted' bytes by stealing memory from existing
! 1002: * dirhashes. Returns zero with list locked if successful.
! 1003: */
! 1004: int
! 1005: ufsdirhash_recycle(int wanted)
! 1006: {
! 1007: struct dirhash *dh;
! 1008: doff_t **hash;
! 1009: u_int8_t *blkfree;
! 1010: int i, mem, narrays;
! 1011:
! 1012: DIRHASHLIST_LOCK();
! 1013: while (wanted + ufs_dirhashmem > ufs_dirhashmaxmem) {
! 1014: /* Find a dirhash, and lock it. */
! 1015: if ((dh = TAILQ_FIRST(&ufsdirhash_list)) == NULL) {
! 1016: DIRHASHLIST_UNLOCK();
! 1017: return (-1);
! 1018: }
! 1019: DIRHASH_LOCK(dh);
! 1020: DIRHASH_ASSERT(dh->dh_hash != NULL, ("dirhash: NULL hash on list"));
! 1021:
! 1022: /* Decrement the score; only recycle if it becomes zero. */
! 1023: if (--dh->dh_score > 0) {
! 1024: DIRHASH_UNLOCK(dh);
! 1025: DIRHASHLIST_UNLOCK();
! 1026: return (-1);
! 1027: }
! 1028:
! 1029: /* Remove it from the list and detach its memory. */
! 1030: TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
! 1031: dh->dh_onlist = 0;
! 1032: hash = dh->dh_hash;
! 1033: dh->dh_hash = NULL;
! 1034: blkfree = dh->dh_blkfree;
! 1035: dh->dh_blkfree = NULL;
! 1036: narrays = dh->dh_narrays;
! 1037: mem = narrays * sizeof(*dh->dh_hash) +
! 1038: narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) +
! 1039: dh->dh_nblk * sizeof(*dh->dh_blkfree);
! 1040:
! 1041: /* Unlock everything, free the detached memory. */
! 1042: DIRHASH_UNLOCK(dh);
! 1043: DIRHASHLIST_UNLOCK();
! 1044: for (i = 0; i < narrays; i++)
! 1045: DIRHASH_BLKFREE(hash[i]);
! 1046: free(hash, M_DIRHASH);
! 1047: free(blkfree, M_DIRHASH);
! 1048:
! 1049: /* Account for the returned memory, and repeat if necessary. */
! 1050: DIRHASHLIST_LOCK();
! 1051: ufs_dirhashmem -= mem;
! 1052: }
! 1053: /* Success; return with list locked. */
! 1054: return (0);
! 1055: }
! 1056:
! 1057:
! 1058: void
! 1059: ufsdirhash_init()
! 1060: {
! 1061: pool_init(&ufsdirhash_pool, DH_NBLKOFF * sizeof(doff_t), 0, 0, 0,
! 1062: "dirhash", &pool_allocator_nointr);
! 1063: pool_sethiwat(&ufsdirhash_pool, 512);
! 1064: TAILQ_INIT(&ufsdirhash_list);
! 1065: #if defined (__sparc__) && !defined (__sparc64__)
! 1066: if (!CPU_ISSUN4OR4C)
! 1067: #elif defined (__vax__)
! 1068: if (0)
! 1069: #endif
! 1070: ufs_dirhashmaxmem = 2 * 1024 * 1024;
! 1071: ufs_mindirhashsize = 5 * DIRBLKSIZ;
! 1072: }
! 1073:
! 1074: void
! 1075: ufsdirhash_uninit()
! 1076: {
! 1077: DIRHASH_ASSERT(TAILQ_EMPTY(&ufsdirhash_list), ("ufsdirhash_uninit"));
! 1078: pool_destroy(&ufsdirhash_pool);
! 1079: }
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