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
68
69
70
71
72
73
74
75
76
77
78
|
/*
* snapshot.c Ceph snapshot context utility routines (part of libceph)
*
* Copyright (C) 2013 Inktank Storage, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <stddef.h>
#include <linux/types.h>
#include <linux/export.h>
#include <linux/ceph/libceph.h>
/*
* Ceph snapshot contexts are reference counted objects, and the
* returned structure holds a single reference. Acquire additional
* references with ceph_get_snap_context(), and release them with
* ceph_put_snap_context(). When the reference count reaches zero
* the entire structure is freed.
*/
/*
* Create a new ceph snapshot context large enough to hold the
* indicated number of snapshot ids (which can be 0). Caller has
* to fill in snapc->seq and snapc->snaps[0..snap_count-1].
*
* Returns a null pointer if an error occurs.
*/
struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
gfp_t gfp_flags)
{
struct ceph_snap_context *snapc;
size_t size;
size = sizeof (struct ceph_snap_context);
size += snap_count * sizeof (snapc->snaps[0]);
snapc = kzalloc(size, gfp_flags);
if (!snapc)
return NULL;
atomic_set(&snapc->nref, 1);
snapc->num_snaps = snap_count;
return snapc;
}
EXPORT_SYMBOL(ceph_create_snap_context);
struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc)
{
if (sc)
atomic_inc(&sc->nref);
return sc;
}
EXPORT_SYMBOL(ceph_get_snap_context);
void ceph_put_snap_context(struct ceph_snap_context *sc)
{
if (!sc)
return;
if (atomic_dec_and_test(&sc->nref)) {
/*printk(" deleting snap_context %p\n", sc);*/
kfree(sc);
}
}
EXPORT_SYMBOL(ceph_put_snap_context);
|
