/* * 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 flag 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 iput * instead of two iputs. * * 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 * * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. */ int filecore_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; /* vnode for directory being searched */ struct filecore_node *dp; /* inode for directory being searched */ struct buf *bp; /* a buffer of directory entries */ struct filecore_direntry *de; int numdirpasses; /* strategy for directory search */ int error; u_short namelen; int res; const char *name; 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; int i, endsearch; flags = cnp->cn_flags; bp = NULL; *vpp = NULL; vdp = ap->a_dvp; dp = VTOI(vdp); /* * Check accessiblity of directory. */ if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) return (error); if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && (cnp->cn_nameiop == DELETE || cnp->cn_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, NULL, vpp)) { return *vpp == NULLVP ? ENOENT : 0; } name = cnp->cn_nameptr; namelen = 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. */ if (nameiop != LOOKUP || dp->i_diroff == 0 || dp->i_diroff >= FILECORE_MAXDIRENTS) { i = 0; numdirpasses = 1; } else { i = dp->i_diroff; numdirpasses = 2; namecache_count_2passes(); } endsearch = FILECORE_MAXDIRENTS; if ((flags & ISDOTDOT) || (name[0] == '.' && namelen == 1)) goto found; error = filecore_dbread(dp, &bp); if (error) { return error; } de = fcdirentry(bp->b_data, i); searchloop: while (de->name[0] != 0 && i < endsearch) { /* * Check for a name match. */ res = filecore_fncmp(de->name, name, namelen); if (res == 0) goto found; if (res < 0) goto notfound; i++; de++; } 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--; i = 0; de = fcdirentry(bp->b_data, i); endsearch = dp->i_diroff; goto searchloop; } if (bp != NULL) { #ifdef FILECORE_DEBUG_BR printf("brelse(%p) lo1\n", bp); #endif brelse(bp, 0); } /* * Insert name into cache (as non-existent) if appropriate. */ cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); return (nameiop == CREATE || nameiop == RENAME) ? EROFS : ENOENT; found: if (numdirpasses == 2) namecache_count_pass2(); /* * 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) dp->i_diroff = i; if (name[0] == '.' && namelen == 1) { vref(vdp); /* we want ourself, ie "." */ *vpp = vdp; } else { ino_t ino; if (flags & ISDOTDOT) { ino = filecore_getparent(dp); } else { ino = dp->i_dirent.addr | (i << FILECORE_INO_INDEX); #ifdef FILECORE_DEBUG_BR printf("brelse(%p) lo4\n", bp); #endif brelse(bp, 0); } error = vcache_get(vdp->v_mount, &ino, sizeof(ino), vpp); if (error) return error; } /* * Insert name into cache if appropriate. */ cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); return 0; }
/* * 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 ext2fs_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 ext2fs_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 ext2fs_direct *ep; /* the current directory entry */ int entryoffsetinblock; /* offset of ep in bp's buffer */ enum {NONE, COMPACT, FOUND} slotstatus; doff_t slotoffset; /* offset of area with free space */ int slotsize; /* size of area at slotoffset */ int slotfreespace; /* amount of space free in slot */ 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; /* prev entry dp->i_offset */ struct vnode *tdp; /* returned by vcache_get */ doff_t enduseful; /* pointer past last used dir slot */ u_long bmask; /* block offset mask */ int namlen, 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; int dirblksiz = ump->um_dirblksiz; ino_t foundino; struct ufs_lookup_results *results; flags = cnp->cn_flags; bp = NULL; slotoffset = -1; *vpp = NULL; /* * 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) && (cnp->cn_nameiop == DELETE || cnp->cn_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, NULL, vpp)) { return *vpp == NULLVP ? ENOENT : 0; } /* * 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 = EXT2FS_DIRSIZ(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; if (nameiop != LOOKUP || results->ulr_diroff == 0 || results->ulr_diroff >= ext2fs_size(dp)) { entryoffsetinblock = 0; results->ulr_offset = 0; numdirpasses = 1; } else { results->ulr_offset = results->ulr_diroff; if ((entryoffsetinblock = results->ulr_offset & bmask) && (error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp))) return (error); numdirpasses = 2; namecache_count_2passes(); } prevoff = results->ulr_offset; endsearch = roundup(ext2fs_size(dp), 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 = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp); if (error != 0) return (error); entryoffsetinblock = 0; } /* * If still looking for a slot, and at a dirblksize * 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 * "dirchk" to be true. */ KASSERT(bp != NULL); ep = (struct ext2fs_direct *) ((char *)bp->b_data + entryoffsetinblock); if (ep->e2d_reclen == 0 || (dirchk && ext2fs_dirbadentry(vdp, ep, entryoffsetinblock))) { int i; ufs_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 = fs2h16(ep->e2d_reclen); if (ep->e2d_ino != 0) size -= EXT2FS_DIRSIZ(ep->e2d_namlen); if (size > 0) { if (size >= slotneeded) { slotstatus = FOUND; slotoffset = results->ulr_offset; slotsize = fs2h16(ep->e2d_reclen); } else if (slotstatus == NONE) { slotfreespace += size; if (slotoffset == -1) slotoffset = results->ulr_offset; if (slotfreespace >= slotneeded) { slotstatus = COMPACT; slotsize = results->ulr_offset + fs2h16(ep->e2d_reclen) - slotoffset; } } } } /* * Check for a name match. */ if (ep->e2d_ino) { namlen = ep->e2d_namlen; if (namlen == cnp->cn_namelen && !memcmp(cnp->cn_nameptr, ep->e2d_name, (unsigned)namlen)) { /* * Save directory entry's inode number and * reclen in ndp->ni_ufs area, and release * directory buffer. */ foundino = fs2h32(ep->e2d_ino); results->ulr_reclen = fs2h16(ep->e2d_reclen); goto found; } } prevoff = results->ulr_offset; results->ulr_offset += fs2h16(ep->e2d_reclen); entryoffsetinblock += fs2h16(ep->e2d_reclen); if (ep->e2d_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) && (flags & ISLASTCN) && dp->i_e2fs_nlink != 0) { /* * Access for write is interpreted as allowing * creation of files in the directory. */ error = VOP_ACCESS(vdp, VWRITE, cred); if (error) return (error); /* * 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(ext2fs_size(dp), dirblksiz); results->ulr_count = 0; enduseful = results->ulr_offset; } else { results->ulr_offset = slotoffset; results->ulr_count = slotsize; if (enduseful < slotoffset + slotsize) enduseful = slotoffset + slotsize; } results->ulr_endoff = roundup(enduseful, dirblksiz); #if 0 dp->i_flag |= 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. */ return (EJUSTRETURN); } /* * 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); } return ENOENT; found: if (numdirpasses == 2) namecache_count_pass2(); /* * Check that directory length properly reflects presence * of this entry. */ if (results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen) > ext2fs_size(dp)) { ufs_dirbad(dp, results->ulr_offset, "i_size too small"); error = ext2fs_setsize(dp, results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen)); if (error) { brelse(bp, 0); return (error); } dp->i_flag |= IN_CHANGE | IN_UPDATE; uvm_vnp_setsize(vdp, ext2fs_size(dp)); } 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) return (error); } /* * Write access to directory required to delete files. */ if ((error = VOP_ACCESS(vdp, VWRITE, cred)) != 0) { vrele(tdp); return (error); } /* * 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_e2fs_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); return (EPERM); } } *vpp = tdp; return (0); } /* * 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) return (error); /* * Careful about locking second inode. * This can only occur if the target is ".". */ if (dp->i_number == foundino) return (EISDIR); error = vcache_get(vdp->v_mount, &foundino, sizeof(foundino), &tdp); if (error) return (error); *vpp = tdp; return (0); } 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) return (error); *vpp = tdp; } /* * Insert name into cache if appropriate. */ cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); return 0; }
/* * 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 */ struct lfs_direct *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 *pdp; /* saved dp during symlink work */ struct vnode *tdp; /* returned by VFS_VGET */ 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; const int needswap = ULFS_MPNEEDSWAP(fs); 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; } 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. */ slotstatus = FOUND; slotfreespace = slotsize = slotneeded = 0; if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN)) { slotstatus = NONE; slotneeded = LFS_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 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 = (struct lfs_direct *)((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 = (struct lfs_direct *)((char *)bp->b_data + entryoffsetinblock); if (ep->d_reclen == 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 = ulfs_rw16(ep->d_reclen, needswap); if (ep->d_ino != 0) size -= LFS_DIRSIZ(FSFMT(vdp), ep, needswap); if (size > 0) { if (size >= slotneeded) { slotstatus = FOUND; slotoffset = results->ulr_offset; slotsize = ulfs_rw16(ep->d_reclen, needswap); } else if (slotstatus == NONE) { slotfreespace += size; if (slotoffset == -1) slotoffset = results->ulr_offset; if (slotfreespace >= slotneeded) { slotstatus = COMPACT; slotsize = results->ulr_offset + ulfs_rw16(ep->d_reclen, needswap) - slotoffset; } } } } /* * Check for a name match. */ if (ep->d_ino) { int namlen; #if (BYTE_ORDER == LITTLE_ENDIAN) if (FSFMT(vdp) && needswap == 0) namlen = ep->d_type; else namlen = ep->d_namlen; #else if (FSFMT(vdp) && needswap != 0) namlen = ep->d_type; else namlen = ep->d_namlen; #endif if (namlen == cnp->cn_namelen && !memcmp(cnp->cn_nameptr, ep->d_name, (unsigned)namlen)) { #ifdef LFS_DIRHASH foundentry: #endif /* * Save directory entry's inode number and * reclen, and release directory buffer. */ if (!FSFMT(vdp) && ep->d_type == LFS_DT_WHT) { slotstatus = FOUND; slotoffset = results->ulr_offset; slotsize = ulfs_rw16(ep->d_reclen, needswap); 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 = ulfs_rw32(ep->d_ino, needswap); results->ulr_reclen = ulfs_rw16(ep->d_reclen, needswap); goto found; } } prevoff = results->ulr_offset; results->ulr_offset += ulfs_rw16(ep->d_reclen, needswap); entryoffsetinblock += ulfs_rw16(ep->d_reclen, needswap); 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; /* * 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_flag |= 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(FSFMT(vdp), ep, needswap) > dp->i_size) { ulfs_dirbad(dp, results->ulr_offset, "i_size too small"); dp->i_size = results->ulr_offset + LFS_DIRSIZ(FSFMT(vdp), ep, needswap); DIP_ASSIGN(dp, size, dp->i_size); dp->i_flag |= 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 { if (flags & ISDOTDOT) VOP_UNLOCK(vdp); /* race to get the inode */ error = VFS_VGET(vdp->v_mount, foundino, &tdp); if (flags & ISDOTDOT) vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY); if (error) goto out; } /* * Write access to directory required to delete files. */ error = VOP_ACCESS(vdp, VWRITE, cred); if (error) { if (dp->i_number == foundino) vrele(tdp); else vput(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) { if (dp->i_number == foundino) vrele(tdp); else vput(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; } if (flags & ISDOTDOT) VOP_UNLOCK(vdp); /* race to get the inode */ error = VFS_VGET(vdp->v_mount, foundino, &tdp); if (flags & ISDOTDOT) vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY); if (error) goto out; *vpp = tdp; error = 0; goto out; } /* * Step through the translation in the name. We do not `vput' the * directory because we may need it again if a symbolic link * is relative to the current directory. Instead we save it * unlocked as "pdp". We must get the target inode before unlocking * the directory to insure that the inode will not be removed * before we get it. We prevent deadlock by always fetching * inodes from the root, moving down the directory tree. Thus * when following backward pointers ".." we must unlock the * parent directory before getting the requested directory. * There is a potential race condition here if both the current * and parent directories are removed before the VFS_VGET for the * inode associated with ".." returns. We hope that this occurs * infrequently since we cannot avoid this race condition without * implementing a sophisticated deadlock detection algorithm. * Note also that this simple deadlock detection scheme will not * work if the file system has any hard links other than ".." * that point backwards in the directory structure. */ pdp = vdp; if (flags & ISDOTDOT) { VOP_UNLOCK(pdp); /* race to get the inode */ error = VFS_VGET(vdp->v_mount, foundino, &tdp); vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY); if (error) { goto out; } *vpp = tdp; } else if (dp->i_number == foundino) { vref(vdp); /* we want ourself, ie "." */ *vpp = vdp; } else { error = VFS_VGET(vdp->v_mount, 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: if (error == 0 && *vpp != vdp) VOP_UNLOCK(*vpp); fstrans_done(vdp->v_mount); return error; }