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/* libdiskfs implementation of fs.defs: dir_link
Copyright (C) 1992,93,94,95,96,97,99 Free Software Foundation, Inc.
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"
#include "fs_S.h"
/* Implement dir_link as described in <hurd/fs.defs>. */
kern_return_t
diskfs_S_dir_link (struct protid *dircred,
struct protid *filecred,
char *name,
int excl)
{
struct node *np; /* node being linked */
struct node *tnp; /* node being deleted implicitly */
struct node *dnp; /* directory of new entry */
struct dirstat *ds = alloca (diskfs_dirstat_size);
error_t error;
if (!dircred)
return EOPNOTSUPP;
if (diskfs_check_readonly ())
return EROFS;
if (!filecred)
return EXDEV;
np = filecred->po->np;
mutex_lock (&np->lock);
if (S_ISDIR (np->dn_stat.st_mode))
{
mutex_unlock (&np->lock);
return EPERM;
}
mutex_unlock (&np->lock);
dnp = dircred->po->np;
mutex_lock (&dnp->lock);
/* Lookup new location */
error = diskfs_lookup (dnp, name, RENAME, &tnp, ds, dircred);
if (!error && excl)
{
error = EEXIST;
diskfs_nput (tnp);
}
if (error && error != ENOENT)
{
if (error == EAGAIN)
error = EINVAL;
diskfs_drop_dirstat (dnp, ds);
mutex_unlock (&dnp->lock);
return error;
}
if (np == tnp)
{
diskfs_drop_dirstat (dnp, ds);
mutex_unlock (&dnp->lock);
mutex_unlock (&tnp->lock);
mach_port_deallocate (mach_task_self (), filecred->pi.port_right);
return 0;
}
if (tnp && S_ISDIR (tnp->dn_stat.st_mode))
{
diskfs_drop_dirstat (dnp, ds);
mutex_unlock (&dnp->lock);
mutex_unlock (&tnp->lock);
return EISDIR;
}
/* Create new entry for NP */
/* This is safe because NP is not a directory (thus not DNP) and
not TNP and is a leaf. */
mutex_lock (&np->lock);
/* Increment link count */
if (np->dn_stat.st_nlink == diskfs_link_max - 1)
{
diskfs_drop_dirstat (dnp, ds);
mutex_unlock (&np->lock);
mutex_unlock (&dnp->lock);
return EMLINK;
}
np->dn_stat.st_nlink++;
np->dn_set_ctime = 1;
diskfs_node_update (np, 1);
/* Attach it */
if (tnp)
{
assert (!excl);
error = diskfs_dirrewrite (dnp, tnp, np, name, ds);
if (!error)
{
/* Deallocate link on TNP */
tnp->dn_stat.st_nlink--;
tnp->dn_set_ctime = 1;
if (diskfs_synchronous)
diskfs_node_update (tnp, 1);
}
diskfs_nput (tnp);
}
else
error = diskfs_direnter (dnp, name, np, ds, dircred);
if (diskfs_synchronous)
diskfs_node_update (dnp, 1);
mutex_unlock (&dnp->lock);
mutex_unlock (&np->lock);
if (!error)
/* MiG won't do this for us, which it ought to. */
mach_port_deallocate (mach_task_self (), filecred->pi.port_right);
return error;
}
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