/* $NetBSD: ufs_lookup.c,v 1.140 2016/04/12 16:12:22 christos Exp $ */ /* * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)ufs_lookup.c 8.9 (Berkeley) 8/11/94 */ #include __KERNEL_RCSID(0, "$NetBSD: ufs_lookup.c,v 1.140 2016/04/12 16:12:22 christos Exp $"); #ifdef _KERNEL_OPT #include "opt_ffs.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef UFS_DIRHASH #include #endif #include #include #include #include #include #ifdef DIAGNOSTIC int dirchk = 1; #else int dirchk = 0; #endif #if BYTE_ORDER == LITTLE_ENDIAN #define ENDIANSWAP 0 #else #define ENDIANSWAP UFS_NEEDSWAP #endif #define NAMLEN(fsfmt, needswap, dp) \ ((fsfmt) && (needswap) == ENDIANSWAP ? (dp)->d_type : dp->d_namlen) static void ufs_dirswap(struct direct *dirp) { u_char tmp = dirp->d_namlen; dirp->d_namlen = dirp->d_type; dirp->d_type = tmp; } struct slotinfo { enum { NONE, /* need to search a slot for our new entry */ COMPACT, /* a compaction can make a slot in the current DIRBLKSIZ block */ FOUND, /* found a slot (or no need to search) */ } status; doff_t offset; /* offset of area with free space. a special value -1 for invalid */ int size; /* size of area at slotoffset */ int freespace; /* accumulated amount of space free in the current DIRBLKSIZ block */ int needed; /* size of the entry we're seeking */ }; static void slot_init(struct slotinfo *slot) { slot->status = FOUND; slot->offset = -1; slot->freespace = slot->size = slot->needed = 0; } #ifdef UFS_DIRHASH static doff_t slot_findfree(struct slotinfo *slot, struct inode *dp) { if (slot->status == FOUND) return dp->i_size; slot->offset = ufsdirhash_findfree(dp, slot->needed, &slot->size); if (slot->offset < 0) return dp->i_size; slot->status = COMPACT; doff_t enduseful = ufsdirhash_enduseful(dp); if (enduseful < 0) return dp->i_size; return enduseful; } #endif static void slot_white(struct slotinfo *slot, uint16_t reclen, struct ufs_lookup_results *results) { slot->status = FOUND; slot->offset = results->ulr_offset; slot->size = reclen; results->ulr_reclen = slot->size; } static void slot_update(struct slotinfo *slot, int size, uint16_t reclen, doff_t offset) { if (size >= slot->needed) { slot->status = FOUND; slot->offset = offset; slot->size = reclen; } else if (slot->status == NONE) { slot->freespace += size; if (slot->offset == -1) slot->offset = offset; if (slot->freespace >= slot->needed) { slot->status = COMPACT; slot->size = offset + reclen - slot->offset; } } } /* * Return an indication of where the new directory entry should be put. * If we didn't find a slot, then set results->ulr_count to 0 indicating * that the new slot belongs at the end of the directory. If we found a slot, * then the new entry can be put in the range from results->ulr_offset to * results->ulr_offset + results->ulr_count. */ static int slot_estimate(const struct slotinfo *slot, int dirblksiz, int nameiop, doff_t prevoff, doff_t enduseful, const struct inode *ip, struct ufs_lookup_results *results) { if (slot->status == NONE) { results->ulr_offset = roundup(ip->i_size, dirblksiz); results->ulr_count = 0; enduseful = results->ulr_offset; } else if (nameiop == DELETE) { results->ulr_offset = slot->offset; if ((results->ulr_offset & (dirblksiz - 1)) == 0) results->ulr_count = 0; else results->ulr_count = results->ulr_offset - prevoff; } else { results->ulr_offset = slot->offset; results->ulr_count = slot->size; if (enduseful < slot->offset + slot->size) enduseful = slot->offset + slot->size; } results->ulr_endoff = roundup(enduseful, dirblksiz); #if 0 /* commented out by dbj. none of the on disk fields changed */ ip->i_flag |= IN_CHANGE | IN_UPDATE; #endif return EJUSTRETURN; } /* * Convert a component of a pathname into a pointer to a locked inode. * This is a very central and rather complicated routine. * If the file system is not maintained in a strict tree hierarchy, * this can result in a deadlock situation (see comments in code below). * * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending * on whether the name is to be looked up, created, renamed, or deleted. * When CREATE, RENAME, or DELETE is specified, information usable in * creating, renaming, or deleting a directory entry may be calculated. * If flag has LOCKPARENT or'ed into it and the target of the pathname * exists, lookup returns both the target and its parent directory locked. * When creating or renaming and LOCKPARENT is specified, the target may * not be ".". When deleting and LOCKPARENT is specified, the target may * be "."., but the caller must check to ensure it does an vrele and vput * instead of two vputs. * * Overall outline of ufs_lookup: * * check accessibility of directory * look for name in cache, if found, then if at end of path * and deleting or creating, drop it, else return name * search for name in directory, to found or notfound * notfound: * if creating, return locked directory, leaving info on available slots * else return error * found: * if at end of path and deleting, return information to allow delete * if at end of path and rewriting (RENAME and LOCKPARENT), lock target * inode and return info to allow rewrite * if not at end, add name to cache; if at end and neither creating * nor deleting, add name to cache */ int ufs_lookup(void *v) { struct vop_lookup_v2_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; } */ *ap = v; struct vnode *vdp = ap->a_dvp; /* vnode for directory being searched */ struct inode *dp = VTOI(vdp); /* inode for directory being searched */ struct buf *bp; /* a buffer of directory entries */ struct direct *ep; /* the current directory entry */ int entryoffsetinblock; /* offset of ep in bp's buffer */ struct slotinfo slot; int numdirpasses; /* strategy for directory search */ doff_t endsearch; /* offset to end directory search */ doff_t prevoff; /* previous value of ulr_offset */ struct vnode *tdp; /* returned by vcache_get */ doff_t enduseful; /* pointer past last used dir slot. used for directory truncation. */ u_long bmask; /* block offset mask */ int error; struct vnode **vpp = ap->a_vpp; struct componentname *cnp = ap->a_cnp; kauth_cred_t cred = cnp->cn_cred; int flags; int nameiop = cnp->cn_nameiop; struct ufsmount *ump = dp->i_ump; const int needswap = UFS_MPNEEDSWAP(ump); int dirblksiz = ump->um_dirblksiz; ino_t foundino; struct ufs_lookup_results *results; int iswhiteout; /* temp result from cache_lookup() */ const int fsfmt = FSFMT(vdp); uint16_t reclen; flags = cnp->cn_flags; bp = NULL; *vpp = NULL; endsearch = 0; /* silence compiler warning */ /* * Produce the auxiliary lookup results into i_crap. Increment * its serial number so elsewhere we can tell if we're using * stale results. This should not be done this way. XXX. */ results = &dp->i_crap; dp->i_crapcounter++; /* * Check accessiblity of directory. */ if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) return (error); if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && (nameiop == DELETE || nameiop == RENAME)) return (EROFS); /* * We now have a segment name to search for, and a directory to search. * * Before tediously performing a linear scan of the directory, * check the name cache to see if the directory/name pair * we are looking for is known already. */ if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_nameiop, cnp->cn_flags, &iswhiteout, vpp)) { if (iswhiteout) { cnp->cn_flags |= ISWHITEOUT; } return *vpp == NULLVP ? ENOENT : 0; } if (iswhiteout) { /* * The namecache set iswhiteout without finding a * cache entry. As of this writing (20121014), this * can happen if there was a whiteout entry that has * been invalidated by the lookup. It is not clear if * it is correct to set ISWHITEOUT in this case or * not; however, doing so retains the prior behavior, * so we'll go with that until some clearer answer * appears. XXX */ cnp->cn_flags |= ISWHITEOUT; } fstrans_start(vdp->v_mount, FSTRANS_SHARED); /* * Suppress search for slots unless creating * file and at end of pathname, in which case * we watch for a place to put the new file in * case it doesn't already exist. */ slot_init(&slot); if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN)) { slot.status = NONE; slot.needed = UFS_DIRECTSIZ(cnp->cn_namelen); } /* * If there is cached information on a previous search of * this directory, pick up where we last left off. * We cache only lookups as these are the most common * and have the greatest payoff. Caching CREATE has little * benefit as it usually must search the entire directory * to determine that the entry does not exist. Caching the * location of the last DELETE or RENAME has not reduced * profiling time and hence has been removed in the interest * of simplicity. */ bmask = vdp->v_mount->mnt_stat.f_iosize - 1; #ifdef UFS_DIRHASH /* * Use dirhash for fast operations on large directories. The logic * to determine whether to hash the directory is contained within * ufsdirhash_build(); a zero return means that it decided to hash * this directory and it successfully built up the hash table. */ if (ufsdirhash_build(dp) == 0) { /* Look for a free slot if needed. */ enduseful = slot_findfree(&slot, dp); /* Look up the component. */ numdirpasses = 1; entryoffsetinblock = 0; /* silence compiler warning */ switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen, &results->ulr_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) { case 0: ep = (void *)((char *)bp->b_data + (results->ulr_offset & bmask)); reclen = ufs_rw16(ep->d_reclen, needswap); goto foundentry; case ENOENT: results->ulr_offset = roundup(dp->i_size, dirblksiz); goto notfound; default: /* Something failed; just do a linear search. */ break; } } #endif /* UFS_DIRHASH */ if (nameiop != LOOKUP || results->ulr_diroff == 0 || results->ulr_diroff >= dp->i_size) { entryoffsetinblock = 0; results->ulr_offset = 0; numdirpasses = 1; } else { results->ulr_offset = results->ulr_diroff; entryoffsetinblock = results->ulr_offset & bmask; if (entryoffsetinblock != 0 && (error = ufs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp, false))) goto out; numdirpasses = 2; namecache_count_2passes(); } prevoff = results->ulr_offset; endsearch = roundup(dp->i_size, dirblksiz); enduseful = 0; searchloop: while (results->ulr_offset < endsearch) { if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) preempt(); /* * If necessary, get the next directory block. */ if ((results->ulr_offset & bmask) == 0) { if (bp != NULL) brelse(bp, 0); error = ufs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp, false); if (error) goto out; entryoffsetinblock = 0; } /* * If still looking for a slot, and at a DIRBLKSIZ * boundary, have to start looking for free space again. */ if (slot.status == NONE && (entryoffsetinblock & (dirblksiz - 1)) == 0) { slot.offset = -1; slot.freespace = 0; } /* * Get pointer to next entry. * Full validation checks are slow, so we only check * enough to insure forward progress through the * directory. Complete checks can be run by patching * "dirchk" to be true. */ KASSERT(bp != NULL); ep = (void *)((char *)bp->b_data + entryoffsetinblock); const char *msg; reclen = ufs_rw16(ep->d_reclen, needswap); if ((reclen == 0 && (msg = "null entry")) || (dirchk && (msg = ufs_dirbadentry(vdp, ep, entryoffsetinblock)))) { ufs_dirbad(dp, results->ulr_offset, msg); reclen = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); goto next; } /* * If an appropriate sized slot has not yet been found, * check to see if one is available. Also accumulate space * in the current block so that we can determine if * compaction is viable. */ if (slot.status != FOUND) { int size = reclen; if (ep->d_ino != 0) size -= UFS_DIRSIZ(fsfmt, ep, needswap); if (size > 0) slot_update(&slot, size, reclen, results->ulr_offset); } if (ep->d_ino == 0) goto next; /* * Check for a name match. */ const uint16_t namlen = NAMLEN(fsfmt, needswap, ep); if (namlen != cnp->cn_namelen || memcmp(cnp->cn_nameptr, ep->d_name, (unsigned)namlen)) goto next; #ifdef UFS_DIRHASH foundentry: #endif /* * Save directory entry's inode number and * reclen, and release directory buffer. */ if (!fsfmt && ep->d_type == DT_WHT) { slot_white(&slot, reclen, results); /* * This is used to set results->ulr_endoff, which may * be used by ufs_direnter() as a length to truncate * the directory to. Therefore, it must point past the * end of the last non-empty directory entry. We don't * know where that is in this case, so we effectively * disable shrinking by using the existing size of the * directory. * * Note that we wouldn't expect to shrink the * directory while rewriting an existing entry anyway. */ enduseful = endsearch; cnp->cn_flags |= ISWHITEOUT; numdirpasses--; goto notfound; } foundino = ufs_rw32(ep->d_ino, needswap); results->ulr_reclen = reclen; goto found; next: prevoff = results->ulr_offset; results->ulr_offset += reclen; entryoffsetinblock += reclen; if (ep->d_ino) enduseful = results->ulr_offset; } notfound: /* * If we started in the middle of the directory and failed * to find our target, we must check the beginning as well. */ if (numdirpasses == 2) { numdirpasses--; results->ulr_offset = 0; endsearch = results->ulr_diroff; goto searchloop; } if (bp != NULL) brelse(bp, 0); /* * If creating, and at end of pathname and current * directory has not been removed, then can consider * allowing file to be created. */ if ((nameiop == CREATE || nameiop == RENAME || (nameiop == DELETE && (cnp->cn_flags & DOWHITEOUT) && (cnp->cn_flags & ISWHITEOUT))) && (flags & ISLASTCN) && dp->i_nlink != 0) { /* * Access for write is interpreted as allowing * creation of files in the directory. */ error = VOP_ACCESS(vdp, VWRITE, cred); if (error) goto out; error = slot_estimate(&slot, dirblksiz, nameiop, prevoff, enduseful, dp, results); /* * We return with the directory locked, so that * the parameters we set up above will still be * valid if we actually decide to do a direnter(). * We return ni_vp == NULL to indicate that the entry * does not currently exist; we leave a pointer to * the (locked) directory inode in ndp->ni_dvp. * * NB - if the directory is unlocked, then this * information cannot be used. */ goto out; } /* * Insert name into cache (as non-existent) if appropriate. */ if (nameiop != CREATE) { cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); } error = ENOENT; goto out; found: if (numdirpasses == 2) namecache_count_pass2(); /* * Check that directory length properly reflects presence * of this entry. */ const uint64_t newisize = results->ulr_offset + UFS_DIRSIZ(fsfmt, ep, needswap); if (newisize > dp->i_size) { ufs_dirbad(dp, results->ulr_offset, "i_size too small"); dp->i_size = newisize; DIP_ASSIGN(dp, size, dp->i_size); dp->i_flag |= IN_CHANGE | IN_UPDATE; UFS_WAPBL_UPDATE(vdp, NULL, NULL, UPDATE_DIROP); } brelse(bp, 0); /* * Found component in pathname. * If the final component of path name, save information * in the cache as to where the entry was found. */ if ((flags & ISLASTCN) && nameiop == LOOKUP) results->ulr_diroff = results->ulr_offset & ~(dirblksiz - 1); /* * If deleting, and at end of pathname, return * parameters which can be used to remove file. * Lock the inode, being careful with ".". */ if (nameiop == DELETE && (flags & ISLASTCN)) { /* * Return pointer to current entry in results->ulr_offset, * and distance past previous entry (if there * is a previous entry in this block) in results->ulr_count. * Save directory inode pointer in ndp->ni_dvp for dirremove(). */ if ((results->ulr_offset & (dirblksiz - 1)) == 0) results->ulr_count = 0; else results->ulr_count = results->ulr_offset - prevoff; if (dp->i_number == foundino) { vref(vdp); tdp = vdp; } else { error = vcache_get(vdp->v_mount, &foundino, sizeof(foundino), &tdp); if (error) goto out; } /* * Write access to directory required to delete files. */ error = VOP_ACCESS(vdp, VWRITE, cred); if (error) { vrele(tdp); goto out; } /* * If directory is "sticky", then user must own * the directory, or the file in it, else she * may not delete it (unless she's root). This * implements append-only directories. */ if (dp->i_mode & ISVTX) { error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE, tdp, vdp, genfs_can_sticky(cred, dp->i_uid, VTOI(tdp)->i_uid)); if (error) { vrele(tdp); error = EPERM; goto out; } } *vpp = tdp; error = 0; goto out; } /* * If rewriting (RENAME), return the inode and the * information required to rewrite the present directory * Must get inode of directory entry to verify it's a * regular file, or empty directory. */ if (nameiop == RENAME && (flags & ISLASTCN)) { error = VOP_ACCESS(vdp, VWRITE, cred); if (error) goto out; /* * Careful about locking second inode. * This can only occur if the target is ".". */ if (dp->i_number == foundino) { error = EISDIR; goto out; } error = vcache_get(vdp->v_mount, &foundino, sizeof(foundino), &tdp); if (error) goto out; *vpp = tdp; error = 0; goto out; } if (dp->i_number == foundino) { vref(vdp); /* we want ourself, ie "." */ *vpp = vdp; } else { error = vcache_get(vdp->v_mount, &foundino, sizeof(foundino), &tdp); if (error) goto out; *vpp = tdp; } /* * Insert name into cache if appropriate. */ cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); error = 0; out: fstrans_done(vdp->v_mount); return error; } void ufs_dirbad(struct inode *ip, doff_t offset, const char *how) { struct mount *mp = ITOV(ip)->v_mount; void (*p)(const char *, ...) __printflike(1, 2) = (mp->mnt_flag & MNT_RDONLY) == 0 ? panic : printf; (*p)("%s: bad dir ino %ju at offset %d: %s\n", mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number, offset, how); } /* * Do consistency checking on a directory entry: * record length must be multiple of 4 * entry must fit in rest of its DIRBLKSIZ block * record must be large enough to contain entry * name is not longer than FFS_MAXNAMLEN * name must be as long as advertised, and null terminated */ const char * ufs_dirbadentry(const struct vnode *dp, const struct direct *ep, int entryoffsetinblock) { const struct ufsmount *ump = VFSTOUFS(dp->v_mount); const int needswap = UFS_MPNEEDSWAP(ump); const int dirblksiz = ump->um_dirblksiz; const int maxsize = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); const int fsfmt = FSFMT(dp); const uint16_t namlen = NAMLEN(fsfmt, needswap, ep); const uint16_t reclen = ufs_rw16(ep->d_reclen, needswap); const int dirsiz = (int)UFS_DIRSIZ(fsfmt, ep, needswap); const char *name = ep->d_name; const char *str; #ifdef DIAGNOSTIC static char buf[512]; #endif if ((reclen & 0x3) != 0) str = "not rounded"; else if (reclen > maxsize) str = "too big"; else if (reclen < dirsiz) str = "too small"; else if (namlen > FFS_MAXNAMLEN) str = "long name"; else str = NULL; if (str) { #ifdef DIAGNOSTIC snprintf(buf, sizeof(buf), "Bad dir (%s), reclen=%#x, " "namlen=%d, dirsiz=%d <= reclen=%d <= maxsize=%d, " "flags=%#x, entryoffsetinblock=%d, dirblksiz=%d\n", str, reclen, namlen, dirsiz, reclen, maxsize, dp->v_mount->mnt_flag, entryoffsetinblock, dirblksiz); str = buf; #endif return str; } if (ep->d_ino == 0) return NULL; for (int i = 0; i < namlen; i++) if (name[i] == '\0') { str = "NUL in name"; #ifdef DIAGNOSTIC snprintf(buf, sizeof(buf), "%s [%s] i=%d, namlen=%d\n", str, name, i, namlen); str = buf; #endif return str; } if (name[namlen]) { str = "missing NUL in name"; #ifdef DIAGNOSTIC snprintf(buf, sizeof(buf), "%s [%*.*s] namlen=%d\n", str, namlen, namlen, name, namlen); str = buf; #endif return str; } return NULL; } /* * Construct a new directory entry after a call to namei, using the * name in the componentname argument cnp. The argument ip is the * inode to which the new directory entry will refer. */ void ufs_makedirentry(struct inode *ip, struct componentname *cnp, struct direct *newdirp) { newdirp->d_ino = ip->i_number; newdirp->d_namlen = cnp->cn_namelen; memcpy(newdirp->d_name, cnp->cn_nameptr, (size_t)cnp->cn_namelen); newdirp->d_name[cnp->cn_namelen] = '\0'; if (FSFMT(ITOV(ip))) newdirp->d_type = 0; else newdirp->d_type = IFTODT(ip->i_mode); } /* * Write a directory entry after a call to namei, using the parameters * that ufs_lookup left in nameidata and in the ufs_lookup_results. * * DVP is the directory to be updated. It must be locked. * ULR is the ufs_lookup_results structure from the final lookup step. * TVP is not used. (XXX: why is it here? remove it) * DIRP is the new directory entry contents. * CNP is the componentname from the final lookup step. * NEWDIRBP is not used and (XXX) should be removed. The previous * comment here said it was used by the now-removed softupdates code. * * The link count of the target inode is *not* incremented; the * caller does that. * * If ulr->ulr_count is 0, ufs_lookup did not find space to insert the * directory entry. ulr_offset, which is the place to put the entry, * should be on a block boundary (and should be at the end of the * directory AFAIK) and a fresh block is allocated to put the new * directory entry in. * * If ulr->ulr_count is not zero, ufs_lookup found a slot to insert * the entry into. This slot ranges from ulr_offset to ulr_offset + * ulr_count. However, this slot may already be partially populated * requiring compaction. See notes below. * * Furthermore, if ulr_count is not zero and ulr_endoff is not the * same as i_size, the directory is truncated to size ulr_endoff. */ int ufs_direnter(struct vnode *dvp, const struct ufs_lookup_results *ulr, struct vnode *tvp, struct direct *dirp, struct componentname *cnp, struct buf *newdirbp) { kauth_cred_t cr; int newentrysize; struct inode *dp; struct buf *bp; u_int dsize; struct direct *ep, *nep; int error, ret, blkoff, loc, spacefree; char *dirbuf; struct timespec ts; struct ufsmount *ump = VFSTOUFS(dvp->v_mount); const int needswap = UFS_MPNEEDSWAP(ump); int dirblksiz = ump->um_dirblksiz; const int fsfmt = FSFMT(dvp); uint16_t reclen; UFS_WAPBL_JLOCK_ASSERT(dvp->v_mount); error = 0; cr = cnp->cn_cred; dp = VTOI(dvp); newentrysize = UFS_DIRSIZ(0, dirp, 0); if (ulr->ulr_count == 0) { /* * If ulr_count is 0, then namei could find no * space in the directory. Here, ulr_offset will * be on a directory block boundary and we will write the * new entry into a fresh block. */ if (ulr->ulr_offset & (dirblksiz - 1)) panic("ufs_direnter: newblk"); if ((error = UFS_BALLOC(dvp, (off_t)ulr->ulr_offset, dirblksiz, cr, B_CLRBUF | B_SYNC, &bp)) != 0) { return (error); } dp->i_size = ulr->ulr_offset + dirblksiz; DIP_ASSIGN(dp, size, dp->i_size); dp->i_flag |= IN_CHANGE | IN_UPDATE; uvm_vnp_setsize(dvp, dp->i_size); dirp->d_reclen = ufs_rw16(dirblksiz, needswap); dirp->d_ino = ufs_rw32(dirp->d_ino, needswap); if (fsfmt && needswap == ENDIANSWAP) ufs_dirswap(dirp); blkoff = ulr->ulr_offset & (ump->um_mountp->mnt_stat.f_iosize - 1); memcpy((char *)bp->b_data + blkoff, dirp, newentrysize); #ifdef UFS_DIRHASH if (dp->i_dirhash != NULL) { ufsdirhash_newblk(dp, ulr->ulr_offset); ufsdirhash_add(dp, dirp, ulr->ulr_offset); ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff, ulr->ulr_offset); } #endif error = VOP_BWRITE(bp->b_vp, bp); vfs_timestamp(&ts); ret = UFS_UPDATE(dvp, &ts, &ts, UPDATE_DIROP); if (error == 0) return (ret); return (error); } /* * If ulr_count is non-zero, then namei found space for the new * entry in the range ulr_offset to ulr_offset + ulr_count * in the directory. To use this space, we may have to compact * the entries located there, by copying them together towards the * beginning of the block, leaving the free space in one usable * chunk at the end. */ /* * Increase size of directory if entry eats into new space. * This should never push the size past a new multiple of * DIRBLKSIZ. * * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. */ if (ulr->ulr_offset + ulr->ulr_count > dp->i_size) { #ifdef DIAGNOSTIC printf("ufs_direnter: reached 4.2-only block, " "not supposed to happen\n"); #endif dp->i_size = ulr->ulr_offset + ulr->ulr_count; DIP_ASSIGN(dp, size, dp->i_size); dp->i_flag |= IN_CHANGE | IN_UPDATE; UFS_WAPBL_UPDATE(dvp, NULL, NULL, UPDATE_DIROP); } /* * Get the block containing the space for the new directory entry. */ error = ufs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp, true); if (error) { return (error); } /* * Find space for the new entry. In the simple case, the entry at * offset base will have the space. If it does not, then namei * arranged that compacting the region ulr_offset to * ulr_offset + ulr_count would yield the space. */ ep = (void *)dirbuf; dsize = (ep->d_ino != 0) ? UFS_DIRSIZ(fsfmt, ep, needswap) : 0; reclen = ufs_rw16(ep->d_reclen, needswap); spacefree = reclen - dsize; for (loc = reclen; loc < ulr->ulr_count; ) { nep = (void *)(dirbuf + loc); /* Trim the existing slot (NB: dsize may be zero). */ ep->d_reclen = ufs_rw16(dsize, needswap); ep = (void *)((char *)ep + dsize); reclen = ufs_rw16(nep->d_reclen, needswap); loc += reclen; if (nep->d_ino == 0) { /* * A mid-block unused entry. Such entries are * never created by the kernel, but fsck_ffs * can create them (and it doesn't fix them). * * Add up the free space, and initialise the * relocated entry since we don't memcpy it. */ spacefree += reclen; ep->d_ino = 0; dsize = 0; continue; } dsize = UFS_DIRSIZ(fsfmt, nep, needswap); spacefree += reclen - dsize; #ifdef UFS_DIRHASH if (dp->i_dirhash != NULL) ufsdirhash_move(dp, nep, ulr->ulr_offset + ((char *)nep - dirbuf), ulr->ulr_offset + ((char *)ep - dirbuf)); #endif memcpy(ep, nep, dsize); } /* * Here, `ep' points to a directory entry containing `dsize' in-use * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0, * then the entry is completely unused (dsize == 0). The value * of ep->d_reclen is always indeterminate. * * Update the pointer fields in the previous entry (if any), * copy in the new entry, and write out the block. */ if (ep->d_ino == 0 || (ufs_rw32(ep->d_ino, needswap) == UFS_WINO && memcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) { if (spacefree + dsize < newentrysize) panic("ufs_direnter: compact1"); dirp->d_reclen = spacefree + dsize; } else { if (spacefree < newentrysize) panic("ufs_direnter: compact2"); dirp->d_reclen = spacefree; ep->d_reclen = ufs_rw16(dsize, needswap); ep = (void *)((char *)ep + dsize); } dirp->d_reclen = ufs_rw16(dirp->d_reclen, needswap); dirp->d_ino = ufs_rw32(dirp->d_ino, needswap); if (fsfmt && needswap == ENDIANSWAP) ufs_dirswap(dirp); #ifdef UFS_DIRHASH if (dp->i_dirhash != NULL && (ep->d_ino == 0 || dirp->d_reclen == spacefree)) ufsdirhash_add(dp, dirp, ulr->ulr_offset + ((char *)ep - dirbuf)); #endif memcpy(ep, dirp, (u_int)newentrysize); #ifdef UFS_DIRHASH if (dp->i_dirhash != NULL) ufsdirhash_checkblock(dp, dirbuf - (ulr->ulr_offset & (dirblksiz - 1)), ulr->ulr_offset & ~(dirblksiz - 1)); #endif error = VOP_BWRITE(bp->b_vp, bp); dp->i_flag |= IN_CHANGE | IN_UPDATE; /* * If all went well, and the directory can be shortened, proceed * with the truncation. Note that we have to unlock the inode for * the entry that we just entered, as the truncation may need to * lock other inodes which can lead to deadlock if we also hold a * lock on the newly entered node. */ if (error == 0 && ulr->ulr_endoff && ulr->ulr_endoff < dp->i_size) { #ifdef UFS_DIRHASH if (dp->i_dirhash != NULL) ufsdirhash_dirtrunc(dp, ulr->ulr_endoff); #endif (void) UFS_TRUNCATE(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, cr); } UFS_WAPBL_UPDATE(dvp, NULL, NULL, UPDATE_DIROP); return (error); } /* * Remove a directory entry after a call to namei, using the * parameters that ufs_lookup left in nameidata and in the * ufs_lookup_results. * * DVP is the directory to be updated. It must be locked. * ULR is the ufs_lookup_results structure from the final lookup step. * IP, if not null, is the inode being unlinked. * FLAGS may contain DOWHITEOUT. * ISRMDIR is not used and (XXX) should be removed. * * If FLAGS contains DOWHITEOUT the entry is replaced with a whiteout * instead of being cleared. * * ulr->ulr_offset contains the position of the directory entry * to be removed. * * ulr->ulr_reclen contains the size of the directory entry to be * removed. * * ulr->ulr_count contains the size of the *previous* directory * entry. This allows finding it, for free space management. If * ulr_count is 0, the target entry is at the beginning of the * directory. (Does this ever happen? The first entry should be ".", * which should only be removed at rmdir time. Does rmdir come here * to clear out the "." and ".." entries? Perhaps, but I doubt it.) * * The space is marked free by adding it to the record length (not * name length) of the preceding entry. If the first entry becomes * free, it is marked free by setting the inode number to 0. * * The link count of IP is decremented. Note that this is not the * inverse behavior of ufs_direnter, which does not adjust link * counts. Sigh. */ int ufs_dirremove(struct vnode *dvp, const struct ufs_lookup_results *ulr, struct inode *ip, int flags, int isrmdir) { struct inode *dp = VTOI(dvp); struct direct *ep; struct buf *bp; int error; const int needswap = UFS_MPNEEDSWAP(dp->i_ump); uint16_t reclen; UFS_WAPBL_JLOCK_ASSERT(dvp->v_mount); if (flags & DOWHITEOUT) { /* * Whiteout entry: set d_ino to UFS_WINO. */ error = ufs_blkatoff(dvp, (off_t)ulr->ulr_offset, &ep, &bp, true); if (error) return (error); ep->d_ino = ufs_rw32(UFS_WINO, needswap); ep->d_type = DT_WHT; goto out; } if ((error = ufs_blkatoff(dvp, (off_t)(ulr->ulr_offset - ulr->ulr_count), &ep, &bp, true)) != 0) return (error); reclen = ufs_rw16(ep->d_reclen, needswap); #ifdef UFS_DIRHASH /* * Remove the dirhash entry. This is complicated by the fact * that `ep' is the previous entry when ulr_count != 0. */ if (dp->i_dirhash != NULL) ufsdirhash_remove(dp, (ulr->ulr_count == 0) ? ep : (void *)((char *)ep + reclen), ulr->ulr_offset); #endif if (ulr->ulr_count == 0) { /* * First entry in block: set d_ino to zero. */ ep->d_ino = 0; } else { /* * Collapse new free space into previous entry. */ ep->d_reclen = ufs_rw16(reclen + ulr->ulr_reclen, needswap); } #ifdef UFS_DIRHASH if (dp->i_dirhash != NULL) { int dirblksiz = ip->i_ump->um_dirblksiz; ufsdirhash_checkblock(dp, (char *)ep - ((ulr->ulr_offset - ulr->ulr_count) & (dirblksiz - 1)), ulr->ulr_offset & ~(dirblksiz - 1)); } #endif out: if (ip) { ip->i_nlink--; DIP_ASSIGN(ip, nlink, ip->i_nlink); ip->i_flag |= IN_CHANGE; UFS_WAPBL_UPDATE(ITOV(ip), NULL, NULL, 0); } /* * XXX did it ever occur to anyone that it might be a good * idea to restore ip->i_nlink if this fails? Or something? * Currently on error return from this function the state of * ip->i_nlink depends on what happened, and callers * definitely do not take this into account. */ error = VOP_BWRITE(bp->b_vp, bp); dp->i_flag |= IN_CHANGE | IN_UPDATE; /* * If the last named reference to a snapshot goes away, * drop its snapshot reference so that it will be reclaimed * when last open reference goes away. */ if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 && ip->i_nlink == 0) UFS_SNAPGONE(ITOV(ip)); UFS_WAPBL_UPDATE(dvp, NULL, NULL, 0); return (error); } /* * Rewrite an existing directory entry to point at the inode supplied. * * DP is the directory to update. * OFFSET is the position of the entry in question. It may come * from ulr_offset of a ufs_lookup_results. * OIP is the old inode the directory previously pointed to. * NEWINUM is the number of the new inode. * NEWTYPE is the new value for the type field of the directory entry. * (This is ignored if the fs doesn't support that.) * ISRMDIR is not used and (XXX) should be removed. * IFLAGS are added to DP's inode flags. * * The link count of OIP is decremented. Note that the link count of * the new inode is *not* incremented. Yay for symmetry. */ int ufs_dirrewrite(struct inode *dp, off_t offset, struct inode *oip, ino_t newinum, int newtype, int isrmdir, int iflags) { struct buf *bp; struct direct *ep; struct vnode *vdp = ITOV(dp); int error; error = ufs_blkatoff(vdp, offset, &ep, &bp, true); if (error) return (error); ep->d_ino = ufs_rw32(newinum, UFS_MPNEEDSWAP(dp->i_ump)); if (!FSFMT(vdp)) ep->d_type = newtype; oip->i_nlink--; DIP_ASSIGN(oip, nlink, oip->i_nlink); oip->i_flag |= IN_CHANGE; UFS_WAPBL_UPDATE(ITOV(oip), NULL, NULL, UPDATE_DIROP); error = VOP_BWRITE(bp->b_vp, bp); dp->i_flag |= iflags; /* * If the last named reference to a snapshot goes away, * drop its snapshot reference so that it will be reclaimed * when last open reference goes away. */ if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_nlink == 0) UFS_SNAPGONE(ITOV(oip)); UFS_WAPBL_UPDATE(vdp, NULL, NULL, UPDATE_DIROP); return (error); } /* * Check if a directory is empty or not. * Inode supplied must be locked. * * Using a struct dirtemplate here is not precisely * what we want, but better than using a struct direct. * * NB: does not handle corrupted directories. */ int ufs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred) { doff_t off; struct dirtemplate dbuf; struct direct *dp = (void *)&dbuf; int error; size_t count; const int needswap = UFS_IPNEEDSWAP(ip); const int fsfmt = FSFMT(ITOV(ip)); #define MINDIRSIZ (sizeof (struct dirtemplate) / 2) for (off = 0; off < ip->i_size; off += ufs_rw16(dp->d_reclen, needswap)) { error = ufs_bufio(UIO_READ, ITOV(ip), dp, MINDIRSIZ, off, IO_NODELOCKED, cred, &count, NULL); /* * Since we read MINDIRSIZ, residual must * be 0 unless we're at end of file. */ if (error || count != 0) return (0); /* avoid infinite loops */ if (dp->d_reclen == 0) return (0); /* skip empty entries */ ino_t ino = ufs_rw32(dp->d_ino, needswap); if (ino == 0 || ino == UFS_WINO) continue; /* accept only "." and ".." */ const uint16_t namlen = NAMLEN(fsfmt, needswap, dp); if (namlen > 2) return (0); if (dp->d_name[0] != '.') return (0); /* * At this point namlen must be 1 or 2. * 1 implies ".", 2 implies ".." if second * char is also "." */ if (namlen == 1 && ino == ip->i_number) continue; if (dp->d_name[1] == '.' && ino == parentino) continue; return (0); } return (1); } #define UFS_DIRRABLKS 0 int ufs_dirrablks = UFS_DIRRABLKS; /* * ufs_blkatoff: Return buffer with the contents of block "offset" from * the beginning of directory "vp". If "res" is non-NULL, fill it in with * a pointer to the remaining space in the directory. If the caller intends * to modify the buffer returned, "modify" must be true. */ int ufs_blkatoff(struct vnode *vp, off_t offset, void *v, struct buf **bpp, bool modify) { char **res = v; struct inode *ip __diagused; struct buf *bp; daddr_t lbn; const int dirrablks = ufs_dirrablks; daddr_t *blks; int *blksizes; int run, error; struct mount *mp = vp->v_mount; const int bshift = mp->mnt_fs_bshift; const int bsize = 1 << bshift; off_t eof; blks = kmem_alloc((1 + dirrablks) * sizeof(daddr_t), KM_SLEEP); blksizes = kmem_alloc((1 + dirrablks) * sizeof(int), KM_SLEEP); ip = VTOI(vp); KASSERT(vp->v_size == ip->i_size); GOP_SIZE(vp, vp->v_size, &eof, 0); lbn = offset >> bshift; for (run = 0; run <= dirrablks;) { const off_t curoff = lbn << bshift; const int size = MIN(eof - curoff, bsize); if (size == 0) { break; } KASSERT(curoff < eof); blks[run] = lbn; blksizes[run] = size; lbn++; run++; if (size != bsize) { break; } } KASSERT(run >= 1); error = breadn(vp, blks[0], blksizes[0], &blks[1], &blksizes[1], run - 1, (modify ? B_MODIFY : 0), &bp); if (error != 0) { *bpp = NULL; goto out; } if (res) { *res = (char *)bp->b_data + (offset & (bsize - 1)); } *bpp = bp; out: kmem_free(blks, (1 + dirrablks) * sizeof(daddr_t)); kmem_free(blksizes, (1 + dirrablks) * sizeof(int)); return error; }