1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
/*
Copyright (C) 1999 Free Software Foundation, Inc.
Written by Thomas Bushnell, BSG.
This file is part of the GNU Hurd.
The GNU Hurd 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.
The GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#include "priv.h"
/* Release a hard reference on NP. If NP is locked by anyone, then
this cannot be the last hard reference (because you must hold a
hard reference in order to hold the lock). If this is the last
hard reference and there are no links, then request soft references
to be dropped. */
void
diskfs_nrele (struct node *np)
{
int locked = FALSE;
struct references result;
/* While we call the diskfs_try_dropping_softrefs, we need to hold
one reference. We use a weak reference for this purpose, which
we acquire by demoting our hard reference to a weak one. */
refcounts_demote (&np->refcounts, &result);
if (result.hard == 0)
{
locked = TRUE;
pthread_mutex_lock (&np->lock);
diskfs_lost_hardrefs (np);
if (!np->dn_stat.st_nlink)
{
/* There are no links. If there are soft references that
can be dropped, we can't let them postpone deallocation.
So attempt to drop them. But that's a user-supplied
routine, which might result in further recursive calls to
the ref-counting system. This is not a problem, as we
hold a weak reference ourselves. */
diskfs_try_dropping_softrefs (np);
}
}
/* Finally get rid of our reference. */
refcounts_deref_weak (&np->refcounts, &result);
if (result.hard == 0 && result.weak == 0)
{
if (! locked)
pthread_mutex_lock (&np->lock);
diskfs_drop_node (np);
}
else if (locked)
pthread_mutex_unlock (&np->lock);
}
|
