X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/de355530ae67247cbd0da700edb3a2a1dae884c2..bd504ef0e0b883cdd7917b73b3574eb9ce669905:/bsd/hfs/hfs_lookup.c diff --git a/bsd/hfs/hfs_lookup.c b/bsd/hfs/hfs_lookup.c index db88b99c0..2200fe1de 100644 --- a/bsd/hfs/hfs_lookup.c +++ b/bsd/hfs/hfs_lookup.c @@ -1,23 +1,29 @@ /* - * Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved. + * Copyright (c) 1999-2012 Apple Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1989, 1993 @@ -65,30 +71,22 @@ * * hfs_lookup.c -- code to handle directory traversal on HFS/HFS+ volume */ -#define LEGACY_FORK_NAMES 0 #include -#include #include #include #include -#include #include -#include +#include +#include +#include +#include #include "hfs.h" #include "hfs_catalog.h" #include "hfs_cnode.h" -static int forkcomponent(struct componentname *cnp, int *rsrcfork); - -#define _PATH_DATAFORKSPEC "/..namedfork/data" - -#ifdef LEGACY_FORK_NAMES -#define LEGACY_RSRCFORKSPEC "/rsrc" -#endif - /* * FROM FREEBSD 3.1 * Convert a component of a pathname into a pointer to a locked cnode. @@ -102,13 +100,6 @@ static int forkcomponent(struct componentname *cnp, int *rsrcfork); * creating, renaming, or deleting a directory entry may be calculated. * Notice that these are the only operations that can affect the directory of the target. * - * 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. - * * LOCKPARENT and WANTPARENT actually refer to the parent of the last item, * so if ISLASTCN is not set, they should be ignored. Also they are mutually exclusive, or * WANTPARENT really implies DONTLOCKPARENT. Either of them set means that the calling @@ -117,10 +108,6 @@ static int forkcomponent(struct componentname *cnp, int *rsrcfork); * Keeping the parent locked as long as possible protects from other processes * looking up the same item, so it has to be locked until the cnode is totally finished * - * This routine is actually used as VOP_CACHEDLOOKUP method, and the - * filesystem employs the generic hfs_cache_lookup() as VOP_LOOKUP - * method. - * * hfs_cache_lookup() performs the following for us: * check that it is a directory * check accessibility of directory @@ -130,7 +117,7 @@ static int forkcomponent(struct componentname *cnp, int *rsrcfork); * drop it * else * return name. - * return VOP_CACHEDLOOKUP() + * return hfs_lookup() * * Overall outline of hfs_lookup: * @@ -147,9 +134,10 @@ static int forkcomponent(struct componentname *cnp, int *rsrcfork); * nor deleting, add name to cache */ + /* - * Lookup *nm in directory *pvp, return it in *a_vpp. - * **a_vpp is held on exit. + * Lookup *cnp in directory *dvp, return it in *vpp. + * **vpp is held on exit. * We create a cnode for the file, but we do NOT open the file here. #% lookup dvp L ? ? @@ -162,88 +150,114 @@ static int forkcomponent(struct componentname *cnp, int *rsrcfork); * When should we lock parent_hp in here ?? */ - -__private_extern__ -int -hfs_lookup(ap) - struct vop_cachedlookup_args /* { - struct vnode *a_dvp; - struct vnode **a_vpp; - struct componentname *a_cnp; - } */ *ap; +static int +hfs_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp, int *cnode_locked) { - struct vnode *dvp; /* vnode for directory being searched */ struct cnode *dcp; /* cnode for directory being searched */ struct vnode *tvp; /* target vnode */ struct hfsmount *hfsmp; - struct componentname *cnp; - struct ucred *cred; - struct proc *p; - int wantrsrc = 0; - int forknamelen = 0; int flags; - int wantparent; int nameiop; int retval = 0; int isDot; - struct cat_desc desc = {0}; + struct cat_desc desc; struct cat_desc cndesc; struct cat_attr attr; struct cat_fork fork; - struct vnode **vpp; + int lockflags; + int newvnode_flags; - vpp = ap->a_vpp; - cnp = ap->a_cnp; - dvp = ap->a_dvp; - dcp = VTOC(dvp); + retry: + newvnode_flags = 0; + dcp = NULL; hfsmp = VTOHFS(dvp); *vpp = NULL; + *cnode_locked = 0; isDot = FALSE; tvp = NULL; nameiop = cnp->cn_nameiop; - cred = cnp->cn_cred; - p = cnp->cn_proc; flags = cnp->cn_flags; - wantparent = flags & (LOCKPARENT|WANTPARENT); + bzero(&desc, sizeof(desc)); /* * First check to see if it is a . or .., else look it up. */ if (flags & ISDOTDOT) { /* Wanting the parent */ + cnp->cn_flags &= ~MAKEENTRY; goto found; /* .. is always defined */ } else if ((cnp->cn_nameptr[0] == '.') && (cnp->cn_namelen == 1)) { isDot = TRUE; + cnp->cn_flags &= ~MAKEENTRY; goto found; /* We always know who we are */ } else { - /* Check fork suffix to see if we want the resource fork */ - forknamelen = forkcomponent(cnp, &wantrsrc); + if (hfs_lock(VTOC(dvp), HFS_EXCLUSIVE_LOCK) != 0) { + retval = ENOENT; /* The parent no longer exists ? */ + goto exit; + } + dcp = VTOC(dvp); + + if (dcp->c_flag & C_DIR_MODIFICATION) { + // XXXdbg - if we could msleep on a lck_rw_t then we would do that + // but since we can't we have to unlock, delay for a bit + // and then retry... + // msleep((caddr_t)&dcp->c_flag, &dcp->c_rwlock, PINOD, "hfs_vnop_lookup", 0); + hfs_unlock(dcp); + tsleep((caddr_t)dvp, PRIBIO, "hfs_lookup", 1); + + goto retry; + } /* No need to go to catalog if there are no children */ - if (dcp->c_entries == 0) + if (dcp->c_entries == 0) { goto notfound; + } bzero(&cndesc, sizeof(cndesc)); - cndesc.cd_nameptr = cnp->cn_nameptr; + cndesc.cd_nameptr = (const u_int8_t *)cnp->cn_nameptr; cndesc.cd_namelen = cnp->cn_namelen; - cndesc.cd_parentcnid = dcp->c_cnid; + cndesc.cd_parentcnid = dcp->c_fileid; cndesc.cd_hint = dcp->c_childhint; - /* Lock catalog b-tree */ - retval = hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_SHARED, p); - if (retval) - goto exit; - retval = cat_lookup(hfsmp, &cndesc, wantrsrc, &desc, &attr, &fork); + lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK); + + retval = cat_lookup(hfsmp, &cndesc, 0, &desc, &attr, &fork, NULL); - if (retval == 0 && S_ISREG(attr.ca_mode) && attr.ca_blocks < fork.cf_blocks) - panic("hfs_lookup: bad ca_blocks (too small)"); - - /* Unlock catalog b-tree */ - (void) hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_RELEASE, p); + hfs_systemfile_unlock(hfsmp, lockflags); + if (retval == 0) { dcp->c_childhint = desc.cd_hint; + /* + * Note: We must drop the parent lock here before calling + * hfs_getnewvnode (which takes the child lock). + */ + hfs_unlock(dcp); + dcp = NULL; + + /* Verify that the item just looked up isn't one of the hidden directories. */ + if (desc.cd_cnid == hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid || + desc.cd_cnid == hfsmp->hfs_private_desc[DIR_HARDLINKS].cd_cnid) { + retval = ENOENT; + goto exit; + } + goto found; } notfound: + /* + * ENAMETOOLONG supersedes other errors + * + * For a CREATE or RENAME operation on the last component + * the ENAMETOOLONG will be handled in the next VNOP. + */ + if ((retval != ENAMETOOLONG) && + (cnp->cn_namelen > kHFSPlusMaxFileNameChars) && + (((flags & ISLASTCN) == 0) || ((nameiop != CREATE) && (nameiop != RENAME)))) { + retval = ENAMETOOLONG; + } else if (retval == 0) { + retval = ENOENT; + } + if (retval != ENOENT) + goto exit; /* * This is a non-existing entry * @@ -253,207 +267,150 @@ notfound: */ if ((nameiop == CREATE || nameiop == RENAME || (nameiop == DELETE && - (ap->a_cnp->cn_flags & DOWHITEOUT) && - (ap->a_cnp->cn_flags & ISWHITEOUT))) && - (flags & ISLASTCN)) { - /* - * Access for write is interpreted as allowing - * creation of files in the directory. - */ - retval = VOP_ACCESS(dvp, VWRITE, cred, cnp->cn_proc); - if (retval) { - goto exit; - } - - cnp->cn_flags |= SAVENAME; - if (!(flags & LOCKPARENT)) - VOP_UNLOCK(dvp, 0, p); + (cnp->cn_flags & DOWHITEOUT) && + (cnp->cn_flags & ISWHITEOUT))) && + (flags & ISLASTCN) && + !(ISSET(dcp->c_flag, C_DELETED | C_NOEXISTS))) { retval = EJUSTRETURN; goto exit; } - /* - * Insert name into cache (as non-existent) if appropriate. - * - * Disable negative caching since HFS is case-insensitive. + * Insert name into the name cache (as non-existent). */ -#if 0 - if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) - cache_enter(dvp, *vpp, cnp); -#endif - retval = ENOENT; + if ((hfsmp->hfs_flags & HFS_STANDARD) == 0 && + (cnp->cn_flags & MAKEENTRY) && + (nameiop != CREATE)) { + cache_enter(dvp, NULL, cnp); + dcp->c_flag |= C_NEG_ENTRIES; + } goto exit; } found: - /* - * Process any fork specifiers - */ - if (forknamelen && S_ISREG(attr.ca_mode)) { - /* fork names are only for lookups */ - if ((nameiop != LOOKUP) && (nameiop != CREATE)) { - retval = EPERM; - goto exit; - } - cnp->cn_consume = forknamelen; - flags |= ISLASTCN; - } else { - wantrsrc = 0; - forknamelen = 0; - } - - /* - * If deleting, and at end of pathname, return - * parameters which can be used to remove file. - */ - if (nameiop == DELETE && (flags & ISLASTCN)) { - /* - * Write access to directory required to delete files. - */ - if ((retval = VOP_ACCESS(dvp, VWRITE, cred, cnp->cn_proc))) - goto exit; - - if (isDot) { /* Want to return ourselves */ - VREF(dvp); - *vpp = dvp; - goto exit; - } else if (flags & ISDOTDOT) { - retval = hfs_getcnode(hfsmp, dcp->c_parentcnid, - NULL, 0, NULL, NULL, &tvp); - if (retval) + if (flags & ISLASTCN) { + switch(nameiop) { + case DELETE: + cnp->cn_flags &= ~MAKEENTRY; + break; + + case RENAME: + cnp->cn_flags &= ~MAKEENTRY; + if (isDot) { + retval = EISDIR; goto exit; - } else { - retval = hfs_getcnode(hfsmp, attr.ca_fileid, - &desc, wantrsrc, &attr, &fork, &tvp); - if (retval) - goto exit; - } - - /* - * 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 ((dcp->c_mode & S_ISTXT) && - (cred->cr_uid != 0) && - (cred->cr_uid != dcp->c_uid) && - (tvp->v_type != VLNK) && - (hfs_owner_rights(hfsmp, VTOC(tvp)->c_uid, cred, p, false))) { - vput(tvp); - retval = EPERM; - goto exit; + } + break; } + } - /* - * If this is a link node then we need to save the name - * (of the link) so we can delete it from the catalog b-tree. - * In this case, hfs_remove will then free the component name. - * - * DJB - IS THIS STILL NEEDED???? - */ - if (tvp && (VTOC(tvp)->c_flag & C_HARDLINK)) - cnp->cn_flags |= SAVENAME; - - if (!(flags & LOCKPARENT)) - VOP_UNLOCK(dvp, 0, p); - *vpp = tvp; - goto exit; - } - - /* - * If renaming, return the cnode and save the current name. - */ - if (nameiop == RENAME && wantparent && (flags & ISLASTCN)) { - if ((retval = VOP_ACCESS(dvp, VWRITE, cred, cnp->cn_proc)) != 0) + if (isDot) { + if ((retval = vnode_get(dvp))) goto exit; + *vpp = dvp; + } else if (flags & ISDOTDOT) { /* - * Careful about locking second cnode. + * Directory hard links can have multiple parents so + * find the appropriate parent for the current thread. */ - if (isDot) { - retval = EISDIR; + if ((retval = hfs_vget(hfsmp, hfs_currentparent(VTOC(dvp)), &tvp, 0, 0))) { goto exit; - } else if (flags & ISDOTDOT) { - retval = hfs_getcnode(hfsmp, dcp->c_parentcnid, - NULL, 0, NULL, NULL, &tvp); - if (retval) - goto exit; - } else { - retval = hfs_getcnode(hfsmp, attr.ca_fileid, - &desc, wantrsrc, &attr, &fork, &tvp); - if (retval) - goto exit; } - cnp->cn_flags |= SAVENAME; - if (!(flags & LOCKPARENT)) - VOP_UNLOCK(dvp, 0, p); + *cnode_locked = 1; *vpp = tvp; - goto exit; - } - - /* - * We must get the target cnode before unlocking - * the directory to insure that the cnode will not be removed - * before we get it. We prevent deadlock by always fetching - * cnodes 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 - * cnode associated with ".." returns. We hope that this occurs - * infrequently since we cannot avoid this race condition without - * implementing a sophisticated deadlock detection algorithm. - */ - if (flags & ISDOTDOT) { - VOP_UNLOCK(dvp, 0, p); /* race to get the cnode */ - retval = hfs_getcnode(hfsmp, dcp->c_parentcnid, - NULL, 0, NULL, NULL, &tvp); - if (retval) { - vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); - goto exit; - } - if ((flags & LOCKPARENT) && (flags & ISLASTCN) && (dvp != tvp) && - (retval = vn_lock(dvp, LK_EXCLUSIVE, p))) { - vput(tvp); - goto exit; - } - *vpp = tvp; - } else if (isDot) { - VREF(dvp); /* we want ourself, ie "." */ - *vpp = dvp; } else { int type = (attr.ca_mode & S_IFMT); - if (!(flags & ISLASTCN) && type != S_IFDIR && type != S_IFLNK) { + if (!(flags & ISLASTCN) && (type != S_IFDIR) && (type != S_IFLNK)) { retval = ENOTDIR; goto exit; } + /* Don't cache directory hardlink names. */ + if (attr.ca_recflags & kHFSHasLinkChainMask) { + cnp->cn_flags &= ~MAKEENTRY; + } + /* Names with composed chars are not cached. */ + if (cnp->cn_namelen != desc.cd_namelen) + cnp->cn_flags &= ~MAKEENTRY; - retval = hfs_getcnode(hfsmp, attr.ca_fileid, - &desc, wantrsrc, &attr, &fork, &tvp); - if (retval) + retval = hfs_getnewvnode(hfsmp, dvp, cnp, &desc, 0, &attr, &fork, &tvp, &newvnode_flags); + + if (retval) { + /* + * If this was a create/rename operation lookup, then by this point + * we expected to see the item returned from hfs_getnewvnode above. + * In the create case, it would probably eventually bubble out an EEXIST + * because the item existed when we were trying to create it. In the + * rename case, it would let us know that we need to go ahead and + * delete it as part of the rename. However, if we hit the condition below + * then it means that we found the element during cat_lookup above, but + * it is now no longer there. We simply behave as though we never found + * the element at all and return EJUSTRETURN. + */ + if ((retval == ENOENT) && + ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME)) && + (flags & ISLASTCN)) { + retval = EJUSTRETURN; + } + + /* + * If this was a straight lookup operation, we may need to redrive the entire + * lookup starting from cat_lookup if the element was deleted as the result of + * a rename operation. Since rename is supposed to guarantee atomicity, then + * lookups cannot fail because the underlying element is deleted as a result of + * the rename call -- either they returned the looked up element prior to rename + * or return the newer element. If we are in this region, then all we can do is add + * workarounds to guarantee the latter case. The element has already been deleted, so + * we just re-try the lookup to ensure the caller gets the most recent element. + */ + if ((retval == ENOENT) && (cnp->cn_nameiop == LOOKUP) && + (newvnode_flags & (GNV_CHASH_RENAMED | GNV_CAT_DELETED))) { + if (dcp) { + hfs_unlock (dcp); + } + /* get rid of any name buffers that may have lingered from the cat_lookup call */ + cat_releasedesc (&desc); + goto retry; + } + + /* Also, re-drive the lookup if the item we looked up was a hardlink, and the number + * or name of hardlinks has changed in the interim between the cat_lookup above, and + * our call to hfs_getnewvnode. hfs_getnewvnode will validate the cattr we passed it + * against what is actually in the catalog after the cnode is created. If there were + * any issues, it will bubble out ERECYCLE, which we need to swallow and use as the + * key to redrive as well. We need to special case this below because in this case, + * it needs to occur regardless of the type of lookup we're doing here. + */ + if ((retval == ERECYCLE) && (newvnode_flags & GNV_CAT_ATTRCHANGED)) { + if (dcp) { + hfs_unlock (dcp); + } + /* get rid of any name buffers that may have lingered from the cat_lookup call */ + cat_releasedesc (&desc); + retval = 0; + goto retry; + } + + /* skip to the error-handling code if we can't retry */ goto exit; + } - if (!(flags & LOCKPARENT) || !(flags & ISLASTCN)) - VOP_UNLOCK(dvp, 0, p); + /* + * Save the origin info for file and directory hardlinks. Directory hardlinks + * need the origin for '..' lookups, and file hardlinks need it to ensure that + * competing lookups do not cause us to vend different hardlinks than the ones requested. + * We want to restrict saving the cache entries to LOOKUP namei operations, since + * we're really doing this to protect getattr. + */ + if ((nameiop == LOOKUP) && (VTOC(tvp)->c_flag & C_HARDLINK)) { + hfs_savelinkorigin(VTOC(tvp), VTOC(dvp)->c_fileid); + } + *cnode_locked = 1; *vpp = tvp; } - - /* - * Insert name in cache if appropriate. - * - "." and ".." are not cached. - * - Resource fork names are not cached. - * - Names with composed chars are not cached. - */ - if ((cnp->cn_flags & MAKEENTRY) - && !isDot - && !(flags & ISDOTDOT) - && !wantrsrc - && (cnp->cn_namelen == VTOC(*vpp)->c_desc.cd_namelen)) { - cache_enter(dvp, *vpp, cnp); - } - exit: + if (dcp) { + hfs_unlock(dcp); + } cat_releasedesc(&desc); return (retval); } @@ -461,8 +418,6 @@ exit: /* - * Based on vn_cache_lookup (which is vfs_cache_lookup in FreeBSD 3.1) - * * Name caching works as follows: * * Names found by directory scans are retained in a cache @@ -480,176 +435,199 @@ exit: * */ -__private_extern__ +#define S_IXALL 0000111 + int -hfs_cache_lookup(ap) - struct vop_lookup_args /* { - struct vnode *a_dvp; - struct vnode **a_vpp; - struct componentname *a_cnp; - } */ *ap; +hfs_vnop_lookup(struct vnop_lookup_args *ap) { - struct vnode *dvp; + struct vnode *dvp = ap->a_dvp; struct vnode *vp; struct cnode *cp; - int lockparent; + struct cnode *dcp; + struct hfsmount *hfsmp; int error; struct vnode **vpp = ap->a_vpp; struct componentname *cnp = ap->a_cnp; - struct ucred *cred = cnp->cn_cred; int flags = cnp->cn_flags; - struct proc *p = cnp->cn_proc; - u_long vpid; /* capability number of vnode */ + int cnode_locked; *vpp = NULL; - dvp = ap->a_dvp; - lockparent = flags & LOCKPARENT; - - /* - * Check accessiblity of directory. - */ - if (dvp->v_type != VDIR) - return (ENOTDIR); - if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && - (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) - return (EROFS); - if ((error = VOP_ACCESS(dvp, VEXEC, cred, cnp->cn_proc))) - return (error); + dcp = VTOC(dvp); + + hfsmp = VTOHFS(dvp); /* * Lookup an entry in the cache - * If the lookup succeeds, the vnode is returned in *vpp, and a status of -1 is - * returned. If the lookup determines that the name does not exist - * (negative cacheing), a status of ENOENT is returned. If the lookup - * fails, a status of zero is returned. + * + * If the lookup succeeds, the vnode is returned in *vpp, + * and a status of -1 is returned. + * + * If the lookup determines that the name does not exist + * (negative cacheing), a status of ENOENT is returned. + * + * If the lookup fails, a status of zero is returned. */ error = cache_lookup(dvp, vpp, cnp); - if (error == 0) { /* Unsuccessfull */ - error = hfs_lookup(ap); - return (error); + if (error != -1) { + if ((error == ENOENT) && (cnp->cn_nameiop != CREATE)) + goto exit; /* found a negative cache entry */ + goto lookup; /* did not find it in the cache */ + } + /* + * We have a name that matched + * cache_lookup returns the vp with an iocount reference already taken + */ + error = 0; + vp = *vpp; + cp = VTOC(vp); + + /* We aren't allowed to vend out vp's via lookup to the hidden directory */ + if (cp->c_cnid == hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid || + cp->c_cnid == hfsmp->hfs_private_desc[DIR_HARDLINKS].cd_cnid) { + /* Drop the iocount from cache_lookup */ + vnode_put (vp); + error = ENOENT; + goto exit; } - if (error == ENOENT) - return (error); - /* We have a name that matched */ - vp = *vpp; - vpid = vp->v_id; - /* * If this is a hard-link vnode then we need to update * the name (of the link), the parent ID, the cnid, the * text encoding and the catalog hint. This enables * getattrlist calls to return the correct link info. */ - cp = VTOC(vp); - if ((flags & ISLASTCN) && (cp->c_flag & C_HARDLINK) && - ((cp->c_parentcnid != VTOC(ap->a_dvp)->c_cnid) || - (bcmp(cnp->cn_nameptr, cp->c_desc.cd_nameptr, cp->c_desc.cd_namelen) != 0))) { - - struct cat_desc desc; - /* - * Get an updated descriptor - */ - bzero(&desc, sizeof(desc)); - desc.cd_nameptr = cnp->cn_nameptr; - desc.cd_namelen = cnp->cn_namelen; - desc.cd_parentcnid = VTOC(ap->a_dvp)->c_cnid; - desc.cd_hint = VTOC(ap->a_dvp)->c_childhint; - if (cat_lookup(VTOHFS(vp), &desc, 0, &desc, NULL, NULL) == 0) - replace_desc(cp, &desc); - } + if ((flags & ISLASTCN) && (cp->c_flag & C_HARDLINK)) { + int stale_link = 0; - if (dvp == vp) { /* lookup on "." */ - VREF(vp); - error = 0; - } else if (flags & ISDOTDOT) { - /* - * Carefull on the locking policy, - * remember we always lock from parent to child, so have - * to release lock on child before trying to lock parent - * then regain lock if needed - */ - VOP_UNLOCK(dvp, 0, p); - error = vget(vp, LK_EXCLUSIVE, p); - if (!error && lockparent && (flags & ISLASTCN)) - error = vn_lock(dvp, LK_EXCLUSIVE, p); - } else { - if ((flags & ISLASTCN) == 0 && vp->v_type == VREG) { - int wantrsrc = 0; + hfs_lock(cp, HFS_FORCE_LOCK); + if ((cp->c_parentcnid != dcp->c_cnid) || + (bcmp(cnp->cn_nameptr, cp->c_desc.cd_nameptr, cp->c_desc.cd_namelen) != 0)) { + struct cat_desc desc; + struct cat_attr lookup_attr; + int lockflags; + /* + * Get an updated descriptor + */ + desc.cd_nameptr = (const u_int8_t *)cnp->cn_nameptr; + desc.cd_namelen = cnp->cn_namelen; + desc.cd_parentcnid = dcp->c_fileid; + desc.cd_hint = dcp->c_childhint; + desc.cd_encoding = 0; + desc.cd_cnid = 0; + desc.cd_flags = S_ISDIR(cp->c_mode) ? CD_ISDIR : 0; - cnp->cn_consume = forkcomponent(cnp, &wantrsrc); + /* + * Because lookups call replace_desc to put a new descriptor in + * the cnode we are modifying it is possible that this cnode's + * descriptor is out of date for the parent ID / name that + * we are trying to look up. (It may point to a different hardlink). + * + * We need to be cautious that when re-supplying the + * descriptor below that the results of the catalog lookup + * still point to the same raw inode for the hardlink. This would + * not be the case if we found something in the cache above but + * the vnode it returned no longer has a valid hardlink for the + * parent ID/filename combo we are requesting. (This is because + * hfs_unlink does not directly trigger namecache removal). + * + * As a result, before vending out the vnode (and replacing + * its descriptor) verify that the fileID is the same by comparing + * the in-cnode attributes vs. the one returned from the lookup call + * below. If they do not match, treat this lookup as if we never hit + * in the cache at all. + */ + + lockflags = hfs_systemfile_lock(VTOHFS(dvp), SFL_CATALOG, HFS_SHARED_LOCK); + + error = cat_lookup(VTOHFS(vp), &desc, 0, &desc, &lookup_attr, NULL, NULL); - /* Fork names are only for lookups */ - if (cnp->cn_consume && - (cnp->cn_nameiop != LOOKUP && cnp->cn_nameiop != CREATE)) - return (EPERM); + hfs_systemfile_unlock(VTOHFS(dvp), lockflags); + /* - * We only store data forks in the name cache. - */ - if (wantrsrc) - return (hfs_lookup(ap)); + * Note that cat_lookup may fail to find something with the name provided in the + * stack-based descriptor above. In that case, an ENOENT is a legitimate errno + * to be placed in error, which will get returned in the fastpath below. + */ + if (error == 0) { + if (lookup_attr.ca_fileid == cp->c_attr.ca_fileid) { + /* It still points to the right raw inode. Replacing the descriptor is fine */ + replace_desc (cp, &desc); + + /* + * Save the origin info for file and directory hardlinks. Directory hardlinks + * need the origin for '..' lookups, and file hardlinks need it to ensure that + * competing lookups do not cause us to vend different hardlinks than the ones requested. + * We want to restrict saving the cache entries to LOOKUP namei operations, since + * we're really doing this to protect getattr. + */ + if (cnp->cn_nameiop == LOOKUP) { + hfs_savelinkorigin(cp, dcp->c_fileid); + } + } + else { + /* If the fileID does not match then do NOT replace the descriptor! */ + stale_link = 1; + } + } } - error = vget(vp, LK_EXCLUSIVE, p); - if (!lockparent || error || !(flags & ISLASTCN)) - VOP_UNLOCK(dvp, 0, p); - } + hfs_unlock (cp); + + if (stale_link) { + /* + * If we had a stale_link, then we need to pretend as though + * we never found this vnode and force a lookup through the + * traditional path. Drop the iocount acquired through + * cache_lookup above and force a cat lookup / getnewvnode + */ + vnode_put(vp); + goto lookup; + } + + if (error) { + /* + * If the cat_lookup failed then the caller will not expect + * a vnode with an iocount on it. + */ + vnode_put(vp); + } + + } + goto exit; + +lookup: /* - * Check that the capability number did not change - * while we were waiting for the lock. + * The vnode was not in the name cache or it was stale. + * + * So we need to do a real lookup. */ - if (!error) { - if (vpid == vp->v_id) - return (0); - /* - * The above is the NORMAL exit, after this point is an error - * condition. - */ - vput(vp); - if (lockparent && (dvp != vp) && (flags & ISLASTCN)) - VOP_UNLOCK(dvp, 0, p); - } - - if ((error = vn_lock(dvp, LK_EXCLUSIVE, p))) - return (error); - - return (hfs_lookup(ap)); -} - + cnode_locked = 0; -/* - * forkcomponent - look for a fork suffix in the component name - * - */ -static int -forkcomponent(struct componentname *cnp, int *rsrcfork) -{ - char *suffix = cnp->cn_nameptr + cnp->cn_namelen; - int consume = 0; + error = hfs_lookup(dvp, vpp, cnp, &cnode_locked); + + if (cnode_locked) + hfs_unlock(VTOC(*vpp)); +exit: + { + uthread_t ut = (struct uthread *)get_bsdthread_info(current_thread()); - *rsrcfork = 0; - if (*suffix == '\0') - return (0); /* - * There are only 3 valid fork suffixes: - * "/..namedfork/rsrc" - * "/..namedfork/data" - * "/rsrc" (legacy) + * check to see if we issued any I/O while completing this lookup and + * this thread/task is throttleable... if so, throttle now + * + * this allows us to throttle in between multiple meta data reads that + * might result due to looking up a long pathname (since we'll have to + * re-enter hfs_vnop_lookup for each component of the pathnam not in + * the VFS cache), instead of waiting until the entire path lookup has + * completed and throttling at the systemcall return */ - if (bcmp(suffix, _PATH_RSRCFORKSPEC, sizeof(_PATH_RSRCFORKSPEC)) == 0) { - consume = sizeof(_PATH_RSRCFORKSPEC) - 1; - *rsrcfork = 1; - } else if (bcmp(suffix, _PATH_DATAFORKSPEC, sizeof(_PATH_DATAFORKSPEC)) == 0) { - consume = sizeof(_PATH_DATAFORKSPEC) - 1; + if (__improbable(ut->uu_lowpri_window)) { + throttle_lowpri_io(TRUE); } - -#ifdef LEGACY_FORK_NAMES - else if (bcmp(suffix, LEGACY_RSRCFORKSPEC, sizeof(LEGACY_RSRCFORKSPEC)) == 0) { - consume = sizeof(LEGACY_RSRCFORKSPEC) - 1; - *rsrcfork = 1; } -#endif - return (consume); + + return (error); } +