/* * ulfs_gro_lookup: Look up and save the lookup results. */ static int ulfs_gro_lookup(struct mount *mp, struct vnode *dvp, struct componentname *cnp, void *de_ret, struct vnode **vp_ret) { struct ulfs_lookup_results *ulr_ret = de_ret; struct vnode *vp = NULL; int error; (void)mp; KASSERT(mp != NULL); KASSERT(dvp != NULL); KASSERT(cnp != NULL); KASSERT(ulr_ret != NULL); KASSERT(vp_ret != NULL); KASSERT(VOP_ISLOCKED(dvp) == LK_EXCLUSIVE); /* Kludge cargo-culted from dholland's ulfs_rename. */ cnp->cn_flags &=~ MODMASK; cnp->cn_flags |= (LOCKPARENT | LOCKLEAF); error = relookup(dvp, &vp, cnp, 0 /* dummy */); if ((error == 0) && (vp == NULL)) { error = ENOENT; goto out; } else if (error) { return error; } /* * Thanks to VFS insanity, relookup locks vp, which screws us * in various ways. */ KASSERT(vp != NULL); VOP_UNLOCK(vp); out: *ulr_ret = VTOI(dvp)->i_crap; *vp_ret = vp; return error; }
/* * Rename system call. * rename("foo", "bar"); * is essentially * unlink("bar"); * link("foo", "bar"); * unlink("foo"); * but ``atomically''. Can't do full commit without saving state in the * inode on disk which isn't feasible at this time. Best we can do is * always guarantee the target exists. * * Basic algorithm is: * * 1) Bump link count on source while we're linking it to the * target. This also ensure the inode won't be deleted out * from underneath us while we work (it may be truncated by * a concurrent `trunc' or `open' for creation). * 2) Link source to destination. If destination already exists, * delete it first. * 3) Unlink source reference to inode if still around. If a * directory was moved and the parent of the destination * is different from the source, patch the ".." entry in the * directory. */ static int ext2_rename(struct vop_rename_args *ap) { struct vnode *tvp = ap->a_tvp; struct vnode *tdvp = ap->a_tdvp; struct vnode *fvp = ap->a_fvp; struct vnode *fdvp = ap->a_fdvp; struct componentname *tcnp = ap->a_tcnp; struct componentname *fcnp = ap->a_fcnp; struct inode *ip, *xp, *dp; struct dirtemplate dirbuf; int doingdirectory = 0, oldparent = 0, newparent = 0; int error = 0; u_char namlen; #ifdef DIAGNOSTIC if ((tcnp->cn_flags & HASBUF) == 0 || (fcnp->cn_flags & HASBUF) == 0) panic("ext2_rename: no name"); #endif /* * Check for cross-device rename. */ if ((fvp->v_mount != tdvp->v_mount) || (tvp && (fvp->v_mount != tvp->v_mount))) { error = EXDEV; abortit: if (tdvp == tvp) vrele(tdvp); else vput(tdvp); if (tvp) vput(tvp); vrele(fdvp); vrele(fvp); return (error); } if (tvp && ((VTOI(tvp)->i_flags & (NOUNLINK | IMMUTABLE | APPEND)) || (VTOI(tdvp)->i_flags & APPEND))) { error = EPERM; goto abortit; } /* * Renaming a file to itself has no effect. The upper layers should * not call us in that case. Temporarily just warn if they do. */ if (fvp == tvp) { printf("ext2_rename: fvp == tvp (can't happen)\n"); error = 0; goto abortit; } if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0) goto abortit; dp = VTOI(fdvp); ip = VTOI(fvp); if (ip->i_nlink >= EXT2_LINK_MAX) { VOP_UNLOCK(fvp, 0); error = EMLINK; goto abortit; } if ((ip->i_flags & (NOUNLINK | IMMUTABLE | APPEND)) || (dp->i_flags & APPEND)) { VOP_UNLOCK(fvp, 0); error = EPERM; goto abortit; } if ((ip->i_mode & IFMT) == IFDIR) { /* * Avoid ".", "..", and aliases of "." for obvious reasons. */ if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') || dp == ip || (fcnp->cn_flags | tcnp->cn_flags) & ISDOTDOT || (ip->i_flag & IN_RENAME)) { VOP_UNLOCK(fvp, 0); error = EINVAL; goto abortit; } ip->i_flag |= IN_RENAME; oldparent = dp->i_number; doingdirectory++; } vrele(fdvp); /* * When the target exists, both the directory * and target vnodes are returned locked. */ dp = VTOI(tdvp); xp = NULL; if (tvp) xp = VTOI(tvp); /* * 1) Bump link count while we're moving stuff * around. If we crash somewhere before * completing our work, the link count * may be wrong, but correctable. */ ip->i_nlink++; ip->i_flag |= IN_CHANGE; if ((error = ext2_update(fvp, !DOINGASYNC(fvp))) != 0) { VOP_UNLOCK(fvp, 0); goto bad; } /* * If ".." must be changed (ie the directory gets a new * parent) then the source directory must not be in the * directory hierarchy above the target, as this would * orphan everything below the source directory. Also * the user must have write permission in the source so * as to be able to change "..". We must repeat the call * to namei, as the parent directory is unlocked by the * call to checkpath(). */ error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_thread); VOP_UNLOCK(fvp, 0); if (oldparent != dp->i_number) newparent = dp->i_number; if (doingdirectory && newparent) { if (error) /* write access check above */ goto bad; if (xp != NULL) vput(tvp); error = ext2_checkpath(ip, dp, tcnp->cn_cred); if (error) goto out; VREF(tdvp); error = relookup(tdvp, &tvp, tcnp); if (error) goto out; vrele(tdvp); dp = VTOI(tdvp); xp = NULL; if (tvp) xp = VTOI(tvp); } /* * 2) If target doesn't exist, link the target * to the source and unlink the source. * Otherwise, rewrite the target directory * entry to reference the source inode and * expunge the original entry's existence. */ if (xp == NULL) { if (dp->i_devvp != ip->i_devvp) panic("ext2_rename: EXDEV"); /* * Account for ".." in new directory. * When source and destination have the same * parent we don't fool with the link count. */ if (doingdirectory && newparent) { if ((nlink_t)dp->i_nlink >= EXT2_LINK_MAX) { error = EMLINK; goto bad; } dp->i_nlink++; dp->i_flag |= IN_CHANGE; error = ext2_update(tdvp, !DOINGASYNC(tdvp)); if (error) goto bad; } error = ext2_direnter(ip, tdvp, tcnp); if (error) { if (doingdirectory && newparent) { dp->i_nlink--; dp->i_flag |= IN_CHANGE; (void)ext2_update(tdvp, 1); } goto bad; } vput(tdvp); } else { if (xp->i_devvp != dp->i_devvp || xp->i_devvp != ip->i_devvp) panic("ext2_rename: EXDEV"); /* * Short circuit rename(foo, foo). */ if (xp->i_number == ip->i_number) panic("ext2_rename: same file"); /* * If the parent directory is "sticky", then the user must * own the parent directory, or the destination of the rename, * otherwise the destination may not be changed (except by * root). This implements append-only directories. */ if ((dp->i_mode & S_ISTXT) && tcnp->cn_cred->cr_uid != 0 && tcnp->cn_cred->cr_uid != dp->i_uid && xp->i_uid != tcnp->cn_cred->cr_uid) { error = EPERM; goto bad; } /* * Target must be empty if a directory and have no links * to it. Also, ensure source and target are compatible * (both directories, or both not directories). */ if ((xp->i_mode&IFMT) == IFDIR) { if (! ext2_dirempty(xp, dp->i_number, tcnp->cn_cred) || xp->i_nlink > 2) { error = ENOTEMPTY; goto bad; } if (!doingdirectory) { error = ENOTDIR; goto bad; } cache_purge(tdvp); } else if (doingdirectory) { error = EISDIR; goto bad; } error = ext2_dirrewrite(dp, ip, tcnp); if (error) goto bad; /* * If the target directory is in the same * directory as the source directory, * decrement the link count on the parent * of the target directory. */ if (doingdirectory && !newparent) { dp->i_nlink--; dp->i_flag |= IN_CHANGE; } vput(tdvp); /* * Adjust the link count of the target to * reflect the dirrewrite above. If this is * a directory it is empty and there are * no links to it, so we can squash the inode and * any space associated with it. We disallowed * renaming over top of a directory with links to * it above, as the remaining link would point to * a directory without "." or ".." entries. */ xp->i_nlink--; if (doingdirectory) { if (--xp->i_nlink != 0) panic("ext2_rename: linked directory"); error = ext2_truncate(tvp, (off_t)0, IO_SYNC, tcnp->cn_cred, tcnp->cn_thread); } xp->i_flag |= IN_CHANGE; vput(tvp); xp = NULL; } /* * 3) Unlink the source. */ fcnp->cn_flags &= ~MODMASK; fcnp->cn_flags |= LOCKPARENT | LOCKLEAF; VREF(fdvp); error = relookup(fdvp, &fvp, fcnp); if (error == 0) vrele(fdvp); if (fvp != NULL) { xp = VTOI(fvp); dp = VTOI(fdvp); } else { /* * From name has disappeared. */ if (doingdirectory) panic("ext2_rename: lost dir entry"); vrele(ap->a_fvp); return (0); } /* * Ensure that the directory entry still exists and has not * changed while the new name has been entered. If the source is * a file then the entry may have been unlinked or renamed. In * either case there is no further work to be done. If the source * is a directory then it cannot have been rmdir'ed; its link * count of three would cause a rmdir to fail with ENOTEMPTY. * The IN_RENAME flag ensures that it cannot be moved by another * rename. */ if (xp != ip) { if (doingdirectory) panic("ext2_rename: lost dir entry"); } else { /* * If the source is a directory with a * new parent, the link count of the old * parent directory must be decremented * and ".." set to point to the new parent. */ if (doingdirectory && newparent) { dp->i_nlink--; dp->i_flag |= IN_CHANGE; error = vn_rdwr(UIO_READ, fvp, (caddr_t)&dirbuf, sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, tcnp->cn_cred, NOCRED, NULL, NULL); if (error == 0) { /* Like ufs little-endian: */ namlen = dirbuf.dotdot_type; if (namlen != 2 || dirbuf.dotdot_name[0] != '.' || dirbuf.dotdot_name[1] != '.') { ext2_dirbad(xp, (doff_t)12, "rename: mangled dir"); } else { dirbuf.dotdot_ino = newparent; (void) vn_rdwr(UIO_WRITE, fvp, (caddr_t)&dirbuf, sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE, IO_NODELOCKED | IO_SYNC | IO_NOMACCHECK, tcnp->cn_cred, NOCRED, NULL, NULL); cache_purge(fdvp); } } } error = ext2_dirremove(fdvp, fcnp); if (!error) { xp->i_nlink--; xp->i_flag |= IN_CHANGE; } xp->i_flag &= ~IN_RENAME; } if (dp) vput(fdvp); if (xp) vput(fvp); vrele(ap->a_fvp); return (error); bad: if (xp) vput(ITOV(xp)); vput(ITOV(dp)); out: if (doingdirectory) ip->i_flag &= ~IN_RENAME; if (vn_lock(fvp, LK_EXCLUSIVE) == 0) { ip->i_nlink--; ip->i_flag |= IN_CHANGE; ip->i_flag &= ~IN_RENAME; vput(fvp); } else vrele(fvp); return (error); }