/*
* 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.
*/
int
ext2fs_rename(void *v)
{
struct vop_rename_args *ap = v;
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 proc *p = fcnp->cn_proc;
struct ext2fs_dirtemplate dirbuf;
/* struct timespec ts; */
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("ext2fs_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:
VOP_ABORTOP(tdvp, tcnp); /* XXX, why not in NFS? */
if (tdvp == tvp)
vrele(tdvp);
else
vput(tdvp);
if (tvp)
vput(tvp);
VOP_ABORTOP(fdvp, fcnp); /* XXX, why not in NFS? */
vrele(fdvp);
vrele(fvp);
return (error);
}
/*
* Check if just deleting a link name.
*/
if (tvp && ((VTOI(tvp)->i_e2fs_flags & (EXT2_IMMUTABLE | EXT2_APPEND)) ||
(VTOI(tdvp)->i_e2fs_flags & EXT2_APPEND))) {
error = EPERM;
goto abortit;
}
if (fvp == tvp) {
if (fvp->v_type == VDIR) {
error = EINVAL;
goto abortit;
}
/* Release destination completely. */
VOP_ABORTOP(tdvp, tcnp);
vput(tdvp);
vput(tvp);
/* Delete source. */
vrele(fdvp);
vrele(fvp);
fcnp->cn_flags &= ~MODMASK;
fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
if ((fcnp->cn_flags & SAVESTART) == 0)
panic("ext2fs_rename: lost from startdir");
fcnp->cn_nameiop = DELETE;
(void) vfs_relookup(fdvp, &fvp, fcnp);
return (VOP_REMOVE(fdvp, fvp, fcnp));
}
if ((error = vn_lock(fvp, LK_EXCLUSIVE, p)) != 0)
goto abortit;
dp = VTOI(fdvp);
ip = VTOI(fvp);
if ((nlink_t)ip->i_e2fs_nlink >= LINK_MAX) {
VOP_UNLOCK(fvp, 0);
error = EMLINK;
goto abortit;
}
if ((ip->i_e2fs_flags & (EXT2_IMMUTABLE | EXT2_APPEND)) ||
(dp->i_e2fs_flags & EXT2_APPEND)) {
VOP_UNLOCK(fvp, 0);
error = EPERM;
goto abortit;
}
if ((ip->i_e2fs_mode & IFMT) == IFDIR) {
error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred);
if (!error && tvp)
error = VOP_ACCESS(tvp, VWRITE, tcnp->cn_cred);
if (error) {
VOP_UNLOCK(fvp, 0);
error = EACCES;
goto abortit;
}
/*
* Avoid ".", "..", and aliases of "." for obvious reasons.
*/
if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
dp == ip ||
(fcnp->cn_flags&ISDOTDOT) ||
(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_e2fs_nlink++;
ip->i_flag |= IN_CHANGE;
if ((error = ext2fs_update(ip, NULL, NULL, 1)) != 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);
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 = ext2fs_checkpath(ip, dp, tcnp->cn_cred);
if (error != 0)
goto out;
if ((tcnp->cn_flags & SAVESTART) == 0)
panic("ext2fs_rename: lost to startdir");
if ((error = vfs_relookup(tdvp, &tvp, tcnp)) != 0)
goto out;
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_dev != ip->i_dev)
panic("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_e2fs_nlink >= LINK_MAX) {
error = EMLINK;
goto bad;
}
dp->i_e2fs_nlink++;
dp->i_flag |= IN_CHANGE;
if ((error = ext2fs_update(dp, NULL, NULL, 1)) != 0)
goto bad;
}
error = ext2fs_direnter(ip, tdvp, tcnp);
if (error != 0) {
if (doingdirectory && newparent) {
dp->i_e2fs_nlink--;
dp->i_flag |= IN_CHANGE;
(void)ext2fs_update(dp, NULL, NULL, 1);
}
goto bad;
}
vput(tdvp);
} else {
if (xp->i_dev != dp->i_dev || xp->i_dev != ip->i_dev)
panic("rename: EXDEV");
/*
* Short circuit rename(foo, foo).
*/
if (xp->i_number == ip->i_number)
panic("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_e2fs_mode & S_ISTXT) && tcnp->cn_cred->cr_uid != 0 &&
tcnp->cn_cred->cr_uid != dp->i_e2fs_uid &&
xp->i_e2fs_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_e2fs_mode & IFMT) == IFDIR) {
if (!ext2fs_dirempty(xp, dp->i_number, tcnp->cn_cred) ||
xp->i_e2fs_nlink > 2) {
error = ENOTEMPTY;
goto bad;
}
if (!doingdirectory) {
error = ENOTDIR;
goto bad;
}
cache_purge(tdvp);
} else if (doingdirectory) {
error = EISDIR;
goto bad;
}
error = ext2fs_dirrewrite(dp, ip, tcnp);
if (error != 0)
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_e2fs_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_e2fs_nlink--;
if (doingdirectory) {
if (--xp->i_e2fs_nlink != 0)
panic("rename: linked directory");
error = ext2fs_truncate(xp, (off_t)0, IO_SYNC,
tcnp->cn_cred);
}
xp->i_flag |= IN_CHANGE;
vput(tvp);
xp = NULL;
}
/*
* 3) Unlink the source.
*/
fcnp->cn_flags &= ~MODMASK;
fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
if ((fcnp->cn_flags & SAVESTART) == 0)
panic("ext2fs_rename: lost from startdir");
(void) vfs_relookup(fdvp, &fvp, fcnp);
if (fvp != NULL) {
xp = VTOI(fvp);
dp = VTOI(fdvp);
} else {
/*
* From name has disappeared.
*/
if (doingdirectory)
panic("ext2fs_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 IRENAME flag ensures that it cannot be moved by another
* rename.
*/
if (xp != ip) {
if (doingdirectory)
panic("ext2fs_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_e2fs_nlink--;
dp->i_flag |= IN_CHANGE;
error = vn_rdwr(UIO_READ, fvp, (caddr_t)&dirbuf,
sizeof (struct ext2fs_dirtemplate), (off_t)0,
UIO_SYSSPACE, IO_NODELOCKED,
tcnp->cn_cred, NULL, curproc);
if (error == 0) {
namlen = dirbuf.dotdot_namlen;
if (namlen != 2 ||
dirbuf.dotdot_name[0] != '.' ||
dirbuf.dotdot_name[1] != '.') {
ufs_dirbad(xp, (doff_t)12,
"ext2fs_rename: mangled dir");
} else {
dirbuf.dotdot_ino = h2fs32(newparent);
(void) vn_rdwr(UIO_WRITE, fvp,
(caddr_t)&dirbuf,
sizeof (struct dirtemplate),
(off_t)0, UIO_SYSSPACE,
IO_NODELOCKED|IO_SYNC,
tcnp->cn_cred, NULL, curproc);
cache_purge(fdvp);
}
}
}
error = ext2fs_dirremove(fdvp, fcnp);
if (!error) {
xp->i_e2fs_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, p) == 0) {
ip->i_e2fs_nlink--;
ip->i_flag |= IN_CHANGE;
vput(fvp);
} else
vrele(fvp);
return (error);
}
/*
* ext2fs_gro_rename: Actually perform the rename operation.
*/
static int
ext2fs_gro_rename(struct mount *mp, kauth_cred_t cred,
struct vnode *fdvp, struct componentname *fcnp,
void *fde, struct vnode *fvp,
struct vnode *tdvp, struct componentname *tcnp,
void *tde, struct vnode *tvp)
{
struct ufs_lookup_results *fulr = fde;
struct ufs_lookup_results *tulr = tde;
bool directory_p, reparent_p;
int error;
(void)mp;
KASSERT(mp != NULL);
KASSERT(fdvp != NULL);
KASSERT(fcnp != NULL);
KASSERT(fulr != NULL);
KASSERT(fvp != NULL);
KASSERT(tdvp != NULL);
KASSERT(tcnp != NULL);
KASSERT(tulr != NULL);
KASSERT(fulr != tulr);
KASSERT(fdvp != fvp);
KASSERT(fdvp != tvp);
KASSERT(tdvp != fvp);
KASSERT(tdvp != tvp);
KASSERT(fvp != tvp);
KASSERT(fdvp->v_mount == mp);
KASSERT(fvp->v_mount == mp);
KASSERT(tdvp->v_mount == mp);
KASSERT((tvp == NULL) || (tvp->v_mount == mp));
KASSERT(VOP_ISLOCKED(fdvp) == LK_EXCLUSIVE);
KASSERT(VOP_ISLOCKED(fvp) == LK_EXCLUSIVE);
KASSERT(VOP_ISLOCKED(tdvp) == LK_EXCLUSIVE);
KASSERT((tvp == NULL) || (VOP_ISLOCKED(tvp) == LK_EXCLUSIVE));
/*
* We shall need to temporarily bump the link count, so make
* sure there is room to do so.
*/
if ((nlink_t)VTOI(fvp)->i_e2fs_nlink >= LINK_MAX)
return EMLINK;
directory_p = (fvp->v_type == VDIR);
KASSERT(directory_p == ((VTOI(fvp)->i_e2fs_mode & IFMT) == IFDIR));
KASSERT((tvp == NULL) || (directory_p == (tvp->v_type == VDIR)));
KASSERT((tvp == NULL) || (directory_p ==
((VTOI(tvp)->i_e2fs_mode & IFMT) == IFDIR)));
reparent_p = (fdvp != tdvp);
KASSERT(reparent_p == (VTOI(fdvp)->i_number != VTOI(tdvp)->i_number));
/*
* Commence hacking of the data on disk.
*/
/*
* 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.
*/
KASSERT((nlink_t)VTOI(fvp)->i_e2fs_nlink < LINK_MAX);
VTOI(fvp)->i_e2fs_nlink++;
VTOI(fvp)->i_flag |= IN_CHANGE;
error = ext2fs_update(fvp, NULL, NULL, UPDATE_WAIT);
if (error)
goto whymustithurtsomuch;
/*
* 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 (tvp == NULL) {
/*
* Account for ".." in new directory.
* When source and destination have the same
* parent we don't fool with the link count.
*/
if (directory_p && reparent_p) {
if ((nlink_t)VTOI(tdvp)->i_e2fs_nlink >= LINK_MAX) {
error = EMLINK;
goto whymustithurtsomuch;
}
KASSERT((nlink_t)VTOI(tdvp)->i_e2fs_nlink < LINK_MAX);
VTOI(tdvp)->i_e2fs_nlink++;
VTOI(tdvp)->i_flag |= IN_CHANGE;
error = ext2fs_update(tdvp, NULL, NULL, UPDATE_WAIT);
if (error) {
/*
* Link count update didn't take --
* back out the in-memory link count.
*/
KASSERT(0 < VTOI(tdvp)->i_e2fs_nlink);
VTOI(tdvp)->i_e2fs_nlink--;
VTOI(tdvp)->i_flag |= IN_CHANGE;
goto whymustithurtsomuch;
}
}
error = ext2fs_direnter(VTOI(fvp), tdvp, tulr, tcnp);
if (error) {
if (directory_p && reparent_p) {
/*
* Directory update didn't take, but
* the link count update did -- back
* out the in-memory link count and the
* on-disk link count.
*/
KASSERT(0 < VTOI(tdvp)->i_e2fs_nlink);
VTOI(tdvp)->i_e2fs_nlink--;
VTOI(tdvp)->i_flag |= IN_CHANGE;
(void)ext2fs_update(tdvp, NULL, NULL,
UPDATE_WAIT);
}
goto whymustithurtsomuch;
}
} else {
if (directory_p)
/* XXX WTF? Why purge here? Why not purge others? */
cache_purge(tdvp);
/*
* Make the target directory's entry for tcnp point at
* the source node.
*/
error = ext2fs_dirrewrite(VTOI(tdvp), tulr, VTOI(fvp), tcnp);
if (error)
goto whymustithurtsomuch;
/*
* If the source and target are directories, and the
* target is in the same directory as the source,
* decrement the link count of the common parent
* directory, since we are removing the target from
* that directory.
*/
if (directory_p && !reparent_p) {
KASSERT(fdvp == tdvp);
/* XXX check, don't kassert */
KASSERT(0 < VTOI(tdvp)->i_e2fs_nlink);
VTOI(tdvp)->i_e2fs_nlink--;
VTOI(tdvp)->i_flag |= IN_CHANGE;
}
/*
* 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.
*/
/* XXX check, don't kassert */
KASSERT(0 < VTOI(tvp)->i_e2fs_nlink);
VTOI(tvp)->i_e2fs_nlink--;
if (directory_p) {
/*
* XXX The ext2fs_dirempty call earlier does
* not guarantee anything about nlink.
*/
if (VTOI(tvp)->i_e2fs_nlink != 1)
ufs_dirbad(VTOI(tvp), (doff_t)0,
"hard-linked directory");
VTOI(tvp)->i_e2fs_nlink = 0;
error = ext2fs_truncate(tvp, (off_t)0, IO_SYNC, cred);
#if 0 /* XXX This branch was not in ext2fs_rename! */
if (error)
goto whymustithurtsomuch;
#endif
}
/*
* XXX Why is this here, and not above the preceding
* conditional?
*/
VTOI(tvp)->i_flag |= IN_CHANGE;
}
/*
* 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 (directory_p && reparent_p) {
error = ext2fs_rename_replace_dotdot(fvp, fdvp, tdvp, cred);
if (error)
goto whymustithurtsomuch;
/* XXX WTF? Why purge here? Why not purge others? */
cache_purge(fdvp);
}
/*
* 3) Unlink the source.
*/
/*
* ext2fs_direnter may compact the directory in the process of
* inserting a new entry. That may invalidate fulr, which we
* need in order to remove the old entry. In that case, we
* need to recalculate what fulr should be.
*/
if (!reparent_p && (tvp == NULL) &&
ext2fs_rename_ulr_overlap_p(fulr, tulr)) {
error = ext2fs_rename_recalculate_fulr(fdvp, fulr, tulr, fcnp);
#if 0 /* XXX */
if (error) /* XXX Try to back out changes? */
goto whymustithurtsomuch;
#endif
}
error = ext2fs_dirremove(fdvp, fulr, fcnp);
if (error)
goto whymustithurtsomuch;
/*
* XXX Perhaps this should go at the top, in case the file
* system is modified but incompletely so because of an
* intermediate error.
*/
genfs_rename_knote(fdvp, fvp, tdvp, tvp,
((tvp != NULL) && (VTOI(tvp)->i_e2fs_nlink == 0)));
#if 0 /* XXX */
genfs_rename_cache_purge(fdvp, fvp, tdvp, tvp);
#endif
whymustithurtsomuch:
KASSERT(0 < VTOI(fvp)->i_e2fs_nlink);
VTOI(fvp)->i_e2fs_nlink--;
VTOI(fvp)->i_flag |= IN_CHANGE;
return error;
}
