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/*
Copyright (C) 1994 Free Software Foundation
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "priv.h"
/* Check if source directory is in the path of the target directory.
We get target locked, source unlocked but with a reference. When
we return, nothing is locked, and target has lost its reference.
This routine assumes that no renames of directories will happen
while it is running; as a result, ufs_rename serializes all renames
of directories. */
static error_t
checkpath(struct node *source,
struct node *target,
struct protid *cred)
{
error_t err;
struct node *np;
np = target;
for (np = target, err = 0;
/* nothing */;
/* This special lookup does a diskfs_nput on its first argument
when it succeeds. */
err = diskfs_lookup (np, "..", LOOKUP | SPEC_DOTDOT, &np, 0, cred))
{
if (err)
{
diskfs_nput (np);
return err;
}
if (np == source)
{
diskfs_nput (np);
return EINVAL;
}
if (np == diskfs_root_node)
{
diskfs_nput (np);
return 0;
}
}
}
/* Rename directory node FNP (whose parent is FDP, and which has name
FROMNAME in that directory) to have name TONAME inside directory
TDP. None of these nodes are locked, and none should be locked
upon return. This routine is serialized, so it doesn't have to be
reentrant. Directories will never be renamed except by this
routine. FROMCRED and TOCRED are the users responsible for
FDP/FNP and TDP respectively. */
error_t
diskfs_rename_dir (struct node *fdp, struct node *fnp, char *fromname,
struct node *tdp, char *toname, struct protid *fromcred,
struct protid *tocred)
{
error_t err;
struct node *tnp, *tmpnp;
void *buf = alloca (diskfs_dirstat_size);
struct dirstat *ds;
struct dirstat *tmpds;
mutex_lock (&tdp->lock);
diskfs_nref (tdp); /* reference and lock will get consumed by
checkpath */
err = checkpath (fnp, tdp, tocred);
if (err)
return err;
/* Now, lock the parent directories. This is legal because tdp is not
a child of fnp (guaranteed by checkpath above). */
mutex_lock (&fdp->lock);
if (fdp != tdp)
mutex_lock (&tdp->lock);
/* 1: Lookup target; if it exists, make sure it's an empty directory. */
ds = buf;
err = diskfs_lookup (tdp, toname, RENAME, &tnp, ds, tocred);
if (tnp == fnp)
{
diskfs_drop_dirstat (tdp, ds);
diskfs_nrele (tnp);
mutex_unlock (&tdp->lock);
mutex_unlock (&fdp->lock);
return 0;
}
/* Now we can safely lock fnp */
mutex_lock (&fnp->lock);
if (tnp)
{
if (! S_ISDIR(tnp->dn_stat.st_mode))
err = ENOTDIR;
else if (!diskfs_dirempty (tnp, tocred))
err = ENOTEMPTY;
}
if (err && err != ENOENT)
goto out;
/* 2: Set our .. to point to the new parent */
if (tdp->dn_stat.st_nlink == diskfs_link_max - 1)
{
err = EMLINK;
return EMLINK;
}
tdp->dn_stat.st_nlink++;
tdp->dn_set_ctime = 1;
tmpds = alloca (diskfs_dirstat_size);
err = diskfs_lookup (fnp, "..", RENAME | SPEC_DOTDOT,
&tmpnp, tmpds, fromcred);
assert (err != ENOENT);
assert (tmpnp == fdp);
diskfs_nrele (tmpnp);
if (err)
{
diskfs_drop_dirstat (fnp, tmpds);
goto out;
}
err = diskfs_dirrewrite (fnp, tdp, tmpds);
if (err)
goto out;
fdp->dn_stat.st_nlink--;
fdp->dn_set_ctime = 1;
/* 3: Increment the link count on the node being moved and rewrite
tdp. */
if (fnp->dn_stat.st_nlink == diskfs_link_max - 1)
{
mutex_unlock (&fnp->lock);
diskfs_drop_dirstat (tdp, ds);
mutex_unlock (&tdp->lock);
if (tnp)
diskfs_nput (tnp);
return EMLINK;
}
fnp->dn_stat.st_nlink++;
fnp->dn_set_ctime = 1;
diskfs_node_update (fnp, 1);
if (tnp)
{
err = diskfs_dirrewrite (tdp, fnp, ds);
ds = 0;
if (!err)
{
tnp->dn_stat.st_nlink--;
tnp->dn_set_ctime = 1;
}
diskfs_clear_directory (tnp, tdp, tocred);
}
else
err = diskfs_direnter (tdp, toname, fnp, ds, tocred);
if (err)
goto out;
/* 4: Remove the entry in fdp. */
ds = buf;
mutex_unlock (&fnp->lock);
err = diskfs_lookup (fdp, fromname, REMOVE, &tmpnp, ds, fromcred);
assert (tmpnp == fnp);
diskfs_nrele (tmpnp);
if (err)
goto out;
diskfs_dirremove (fdp, ds);
ds = 0;
fnp->dn_stat.st_nlink--;
fnp->dn_set_ctime = 1;
out:
if (tdp)
mutex_unlock (&tdp->lock);
if (tnp)
diskfs_nput (tnp);
if (fdp)
mutex_unlock (&fdp->lock);
if (fnp)
mutex_unlock (&fnp->lock);
if (ds)
diskfs_drop_dirstat (tdp, ds);
return err;
}
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