/* $NetBSD: ulfs_lookup.c,v 1.40.6.1 2017/10/30 09:29:04 snj Exp $ */ /* from NetBSD: ufs_lookup.c,v 1.135 2015/07/11 11:04:48 mlelstv */ /* * 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: ulfs_lookup.c,v 1.40.6.1 2017/10/30 09:29:04 snj Exp $"); #ifdef _KERNEL_OPT #include "opt_lfs.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef LFS_DIRHASH #include #endif #include #include #include #include #ifdef DIAGNOSTIC int lfs_dirchk = 1; #else int lfs_dirchk = 0; #endif /* * 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 ulfs_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 ulfs_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 */ LFS_DIRHEADER *ep; /* the current directory entry */ int entryoffsetinblock; /* offset of ep in bp's buffer */ 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) */ } slotstatus; doff_t slotoffset; /* offset of area with free space. a special value -1 for invalid */ int slotsize; /* size of area at slotoffset */ int slotfreespace; /* accumulated amount of space free in the current DIRBLKSIZ block */ int slotneeded; /* size of the entry we're seeking */ 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 lfs *fs = dp->i_lfs; int dirblksiz = fs->um_dirblksiz; ino_t foundino; struct ulfs_lookup_results *results; int iswhiteout; /* temp result from cache_lookup() */ flags = cnp->cn_flags; bp = NULL; slotoffset = -1; *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; } /* * 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. */ slotstatus = FOUND; slotfreespace = slotsize = slotneeded = 0; if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN)) { slotstatus = NONE; slotneeded = LFS_DIRECTSIZ(fs, 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 LFS_DIRHASH /* * Use dirhash for fast operations on large directories. The logic * to determine whether to hash the directory is contained within * ulfsdirhash_build(); a zero return means that it decided to hash * this directory and it successfully built up the hash table. */ if (ulfsdirhash_build(dp) == 0) { /* Look for a free slot if needed. */ enduseful = dp->i_size; if (slotstatus != FOUND) { slotoffset = ulfsdirhash_findfree(dp, slotneeded, &slotsize); if (slotoffset >= 0) { slotstatus = COMPACT; enduseful = ulfsdirhash_enduseful(dp); if (enduseful < 0) enduseful = dp->i_size; } } /* Look up the component. */ numdirpasses = 1; entryoffsetinblock = 0; /* silence compiler warning */ switch (ulfsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen, &results->ulr_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) { case 0: ep = (LFS_DIRHEADER *)((char *)bp->b_data + (results->ulr_offset & bmask)); goto foundentry; case ENOENT: results->ulr_offset = roundup(dp->i_size, dirblksiz); goto notfound; default: /* Something failed; just do a linear search. */ break; } } #endif /* LFS_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; if ((entryoffsetinblock = results->ulr_offset & bmask) && (error = ulfs_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 = ulfs_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 (slotstatus == NONE && (entryoffsetinblock & (dirblksiz - 1)) == 0) { slotoffset = -1; slotfreespace = 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 * "lfs_dirchk" to be true. */ KASSERT(bp != NULL); ep = (LFS_DIRHEADER *)((char *)bp->b_data + entryoffsetinblock); if (lfs_dir_getreclen(fs, ep) == 0 || (lfs_dirchk && ulfs_dirbadentry(vdp, ep, entryoffsetinblock))) { int i; ulfs_dirbad(dp, results->ulr_offset, "mangled entry"); i = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); results->ulr_offset += i; entryoffsetinblock += i; continue; } /* * 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 (slotstatus != FOUND) { int size = lfs_dir_getreclen(fs, ep); if (lfs_dir_getino(fs, ep) != 0) size -= LFS_DIRSIZ(fs, ep); if (size > 0) { if (size >= slotneeded) { slotstatus = FOUND; slotoffset = results->ulr_offset; slotsize = lfs_dir_getreclen(fs, ep); } else if (slotstatus == NONE) { slotfreespace += size; if (slotoffset == -1) slotoffset = results->ulr_offset; if (slotfreespace >= slotneeded) { slotstatus = COMPACT; slotsize = results->ulr_offset + lfs_dir_getreclen(fs, ep) - slotoffset; } } } } /* * Check for a name match. */ if (lfs_dir_getino(fs, ep)) { int namlen; namlen = lfs_dir_getnamlen(fs, ep); if (namlen == cnp->cn_namelen && !memcmp(cnp->cn_nameptr, lfs_dir_nameptr(fs, ep), (unsigned)namlen)) { #ifdef LFS_DIRHASH foundentry: #endif /* * Save directory entry's inode number and * reclen, and release directory buffer. */ if (!FSFMT(vdp) && lfs_dir_gettype(fs, ep) == LFS_DT_WHT) { slotstatus = FOUND; slotoffset = results->ulr_offset; slotsize = lfs_dir_getreclen(fs, ep); results->ulr_reclen = slotsize; /* * This is used to set * results->ulr_endoff, * which may be used by ulfs_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 = lfs_dir_getino(fs, ep); results->ulr_reclen = lfs_dir_getreclen(fs, ep); goto found; } } prevoff = results->ulr_offset; results->ulr_offset += lfs_dir_getreclen(fs, ep); entryoffsetinblock += lfs_dir_getreclen(fs, ep); if (lfs_dir_getino(fs, ep)) 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; /* * 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. */ if (slotstatus == NONE) { results->ulr_offset = roundup(dp->i_size, dirblksiz); results->ulr_count = 0; enduseful = results->ulr_offset; } else if (nameiop == DELETE) { results->ulr_offset = slotoffset; if ((results->ulr_offset & (dirblksiz - 1)) == 0) results->ulr_count = 0; else results->ulr_count = results->ulr_offset - prevoff; } else { results->ulr_offset = slotoffset; results->ulr_count = slotsize; if (enduseful < slotoffset + slotsize) enduseful = slotoffset + slotsize; } results->ulr_endoff = roundup(enduseful, dirblksiz); #if 0 /* commented out by dbj. none of the on disk fields changed */ dp->i_state |= IN_CHANGE | IN_UPDATE; #endif /* * 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. */ error = EJUSTRETURN; 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. */ if (results->ulr_offset + LFS_DIRSIZ(fs, ep) > dp->i_size) { ulfs_dirbad(dp, results->ulr_offset, "i_size too small"); dp->i_size = results->ulr_offset + LFS_DIRSIZ(fs, ep); DIP_ASSIGN(dp, size, dp->i_size); dp->i_state |= IN_CHANGE | IN_UPDATE; } 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: return error; } void ulfs_dirbad(struct inode *ip, doff_t offset, const char *how) { struct mount *mp; mp = ITOV(ip)->v_mount; printf("%s: bad dir ino %llu at offset %d: %s\n", mp->mnt_stat.f_mntonname, (unsigned long long)ip->i_number, offset, how); if ((mp->mnt_flag & MNT_RDONLY) == 0) panic("bad dir"); } /* * 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 LFS_MAXNAMLEN * name must be as long as advertised, and null terminated */ int ulfs_dirbadentry(struct vnode *dp, LFS_DIRHEADER *ep, int entryoffsetinblock) { int i; int namlen; unsigned reclen; struct ulfsmount *ump = VFSTOULFS(dp->v_mount); struct lfs *fs = ump->um_lfs; int dirblksiz = fs->um_dirblksiz; const char *name; namlen = lfs_dir_getnamlen(fs, ep); reclen = lfs_dir_getreclen(fs, ep); if ((reclen & 0x3) != 0 || reclen > dirblksiz - (entryoffsetinblock & (dirblksiz - 1)) || reclen < LFS_DIRSIZ(fs, ep) || namlen > LFS_MAXNAMLEN) { /*return (1); */ printf("First bad, reclen=%#x, DIRSIZ=%lu, namlen=%d, " "flags=%#x, entryoffsetinblock=%d, dirblksiz = %d\n", lfs_dir_getreclen(fs, ep), (u_long)LFS_DIRSIZ(fs, ep), namlen, dp->v_mount->mnt_flag, entryoffsetinblock, dirblksiz); goto bad; } if (lfs_dir_getino(fs, ep) == 0) return (0); name = lfs_dir_nameptr(fs, ep); for (i = 0; i < namlen; i++) if (name[i] == '\0') { /*return (1); */ printf("Second bad\n"); goto bad; } if (name[i]) goto bad; return (0); bad: return (1); } /* * Assign the contents of directory entry DIRP, on volume FS. * * NAME/NAMLEN is the name, which is not necessarily null terminated. * INUM is the inode number, and DTYPE is the type code (LFS_DT_*). * * Note that these values typically come from: * cnp->cn_nameptr * cnp->cn_namelen * ip->i_number * LFS_IFTODT(ip->i_mode) * * Does not set d_reclen. */ static void ulfs_direntry_assign(struct lfs *fs, LFS_DIRHEADER *dirp, const char *name, size_t namlen, ino_t inum, unsigned dtype) { lfs_dir_setino(fs, dirp, inum); lfs_dir_setnamlen(fs, dirp, namlen); lfs_dir_settype(fs, dirp, dtype); memcpy(lfs_dir_nameptr(fs, dirp), name, namlen); lfs_dir_nameptr(fs, dirp)[namlen] = '\0'; } /* * Write a directory entry after a call to namei, using the parameters * that ulfs_lookup left in nameidata and in the ulfs_lookup_results. * * DVP is the directory to be updated. It must be locked. * ULR is the ulfs_lookup_results structure from the final lookup step. * TVP is not used. (XXX: why is it here? remove it) * CNP is the componentname from the final lookup step. * INUM is the inode number to insert into the new directory entry. * DTYPE is the type code (LFS_DT_*) to insert into the new directory entry. * 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, ulfs_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, ulfs_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 ulfs_direnter(struct vnode *dvp, const struct ulfs_lookup_results *ulr, struct vnode *tvp, struct componentname *cnp, ino_t inum, unsigned dtype, struct buf *newdirbp) { kauth_cred_t cr; int newentrysize; struct inode *dp; struct buf *bp; u_int dsize; LFS_DIRHEADER *ep, *nep; int error, ret, lfs_blkoff, loc, spacefree; char *dirbuf; struct timespec ts; struct ulfsmount *ump = VFSTOULFS(dvp->v_mount); struct lfs *fs = ump->um_lfs; int dirblksiz = fs->um_dirblksiz; const char *name; unsigned namlen, reclen; #ifdef LFS_DIRHASH int dohashadd; #endif error = 0; name = cnp->cn_nameptr; /* note: not null-terminated */ namlen = cnp->cn_namelen; cr = cnp->cn_cred; dp = VTOI(dvp); newentrysize = LFS_DIRECTSIZ(fs, namlen); 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("ulfs_direnter: newblk"); if ((error = lfs_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_state |= IN_CHANGE | IN_UPDATE; uvm_vnp_setsize(dvp, dp->i_size); lfs_blkoff = ulr->ulr_offset & (ump->um_mountp->mnt_stat.f_iosize - 1); ep = (LFS_DIRHEADER *)((char *)bp->b_data + lfs_blkoff); ulfs_direntry_assign(fs, ep, name, namlen, inum, dtype); lfs_dir_setreclen(fs, ep, dirblksiz); #ifdef LFS_DIRHASH if (dp->i_dirhash != NULL) { ulfsdirhash_newblk(dp, ulr->ulr_offset); ulfsdirhash_add(dp, ep, ulr->ulr_offset); ulfsdirhash_checkblock(dp, (char *)bp->b_data + lfs_blkoff, ulr->ulr_offset); } #endif error = VOP_BWRITE(bp->b_vp, bp); vfs_timestamp(&ts); ret = lfs_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("ulfs_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_state |= IN_CHANGE | IN_UPDATE; } /* * Get the block containing the space for the new directory entry. */ error = ulfs_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 = (LFS_DIRHEADER *)dirbuf; dsize = (lfs_dir_getino(fs, ep) != 0) ? LFS_DIRSIZ(fs, ep) : 0; spacefree = lfs_dir_getreclen(fs, ep) - dsize; for (loc = lfs_dir_getreclen(fs, ep); loc < ulr->ulr_count; ) { nep = (LFS_DIRHEADER *)(dirbuf + loc); /* Trim the existing slot (NB: dsize may be zero). */ lfs_dir_setreclen(fs, ep, dsize); ep = LFS_NEXTDIR(fs, ep); reclen = lfs_dir_getreclen(fs, nep); loc += reclen; if (lfs_dir_getino(fs, nep) == 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; lfs_dir_setino(fs, ep, 0); dsize = 0; continue; } dsize = LFS_DIRSIZ(fs, nep); spacefree += reclen - dsize; #ifdef LFS_DIRHASH if (dp->i_dirhash != NULL) ulfsdirhash_move(dp, nep, ulr->ulr_offset + ((char *)nep - dirbuf), ulr->ulr_offset + ((char *)ep - dirbuf)); #endif memcpy((void *)ep, (void *)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 (lfs_dir_getino(fs, ep) == 0 || (lfs_dir_getino(fs, ep) == ULFS_WINO && memcmp(lfs_dir_nameptr(fs, ep), name, namlen) == 0)) { if (spacefree + dsize < newentrysize) panic("ulfs_direnter: compact1"); reclen = spacefree + dsize; #ifdef LFS_DIRHASH dohashadd = (lfs_dir_getino(fs, ep) == 0); #endif } else { if (spacefree < newentrysize) panic("ulfs_direnter: compact2"); reclen = spacefree; lfs_dir_setreclen(fs, ep, dsize); ep = LFS_NEXTDIR(fs, ep); #ifdef LFS_DIRHASH dohashadd = 1; #endif } ulfs_direntry_assign(fs, ep, name, namlen, inum, dtype); lfs_dir_setreclen(fs, ep, reclen); #ifdef LFS_DIRHASH if (dp->i_dirhash != NULL && dohashadd) ulfsdirhash_add(dp, ep, ulr->ulr_offset + ((char *)ep - dirbuf)); if (dp->i_dirhash != NULL) ulfsdirhash_checkblock(dp, dirbuf - (ulr->ulr_offset & (dirblksiz - 1)), ulr->ulr_offset & ~(dirblksiz - 1)); #endif error = VOP_BWRITE(bp->b_vp, bp); dp->i_state |= 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 LFS_DIRHASH if (dp->i_dirhash != NULL) ulfsdirhash_dirtrunc(dp, ulr->ulr_endoff); #endif (void) lfs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, cr); } return (error); } /* * Remove a directory entry after a call to namei, using the * parameters that ulfs_lookup left in nameidata and in the * ulfs_lookup_results. * * DVP is the directory to be updated. It must be locked. * ULR is the ulfs_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 ulfs_direnter, which does not adjust link * counts. Sigh. */ int ulfs_dirremove(struct vnode *dvp, const struct ulfs_lookup_results *ulr, struct inode *ip, int flags, int isrmdir) { struct inode *dp = VTOI(dvp); struct lfs *fs = dp->i_lfs; LFS_DIRHEADER *ep; struct buf *bp; int error; if (flags & DOWHITEOUT) { /* * Whiteout entry: set d_ino to ULFS_WINO. */ error = ulfs_blkatoff(dvp, (off_t)ulr->ulr_offset, (void *)&ep, &bp, true); if (error) return (error); lfs_dir_setino(fs, ep, ULFS_WINO); lfs_dir_settype(fs, ep, LFS_DT_WHT); goto out; } if ((error = ulfs_blkatoff(dvp, (off_t)(ulr->ulr_offset - ulr->ulr_count), (void *)&ep, &bp, true)) != 0) return (error); #ifdef LFS_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) ulfsdirhash_remove(dp, (ulr->ulr_count == 0) ? ep : LFS_NEXTDIR(fs, ep), ulr->ulr_offset); #endif if (ulr->ulr_count == 0) { /* * First entry in block: set d_ino to zero. */ lfs_dir_setino(fs, ep, 0); } else { /* * Collapse new free space into previous entry. */ lfs_dir_setreclen(fs, ep, lfs_dir_getreclen(fs, ep) + ulr->ulr_reclen); } #ifdef LFS_DIRHASH if (dp->i_dirhash != NULL) { int dirblksiz = ip->i_lfs->um_dirblksiz; ulfsdirhash_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_state |= IN_CHANGE; } /* * 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_state |= 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) ulfs_snapgone(ip); 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 ulfs_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 ulfs_dirrewrite(struct inode *dp, off_t offset, struct inode *oip, ino_t newinum, int newtype, int isrmdir, int iflags) { struct lfs *fs = dp->i_lfs; struct buf *bp; LFS_DIRHEADER *ep; struct vnode *vdp = ITOV(dp); int error; error = ulfs_blkatoff(vdp, offset, (void *)&ep, &bp, true); if (error) return (error); lfs_dir_setino(fs, ep, newinum); lfs_dir_settype(fs, ep, newtype); oip->i_nlink--; DIP_ASSIGN(oip, nlink, oip->i_nlink); oip->i_state |= IN_CHANGE; error = VOP_BWRITE(bp->b_vp, bp); dp->i_state |= 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) ulfs_snapgone(oip); return (error); } /* * Check if a directory is empty or not. * Inode supplied must be locked. * * Using a struct lfs_dirtemplate here is not precisely * what we want, but better than using a struct lfs_direct. * * NB: does not handle corrupted directories. */ int ulfs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred) { struct lfs *fs = ip->i_lfs; doff_t off; union lfs_dirtemplate dbuf; LFS_DIRHEADER *dp = (LFS_DIRHEADER *)&dbuf; int error, namlen; const char *name; size_t count; /* XXX this should probably use LFS_DIRECTSIZ(fs, 2) */ #define MINDIRSIZ (sizeof (struct lfs_dirtemplate64) / 2) for (off = 0; off < ip->i_size; off += lfs_dir_getreclen(fs, dp)) { error = ulfs_bufio(UIO_READ, ITOV(ip), (void *)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 (lfs_dir_getreclen(fs, dp) == 0) return (0); /* skip empty entries */ if (lfs_dir_getino(fs, dp) == 0 || lfs_dir_getino(fs, dp) == ULFS_WINO) continue; /* accept only "." and ".." */ namlen = lfs_dir_getnamlen(fs, dp); name = lfs_dir_nameptr(fs, dp); if (namlen > 2) return (0); if (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 && lfs_dir_getino(fs, dp) == ip->i_number) continue; if (name[1] == '.' && lfs_dir_getino(fs, dp) == parentino) continue; return (0); } return (1); } #define ULFS_DIRRABLKS 0 int ulfs_dirrablks = ULFS_DIRRABLKS; /* * ulfs_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 ulfs_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp, bool modify) { struct inode *ip __diagused; struct buf *bp; daddr_t lbn; const int dirrablks = ulfs_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; }