xref: /dragonfly/lib/libhammer/snapshot.c (revision a4da4a90)
1 /*
2  * Copyright (c) 2015 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Antonio Huete <tuxillo@quantumachine.net>
6  * by Matthew Dillon <dillon@backplane.com>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 
37 #include <assert.h>
38 #include <stdio.h>
39 #include <strings.h>
40 #include <string.h>
41 #include <stdlib.h>
42 #include <fcntl.h>
43 #include <errno.h>
44 #include <unistd.h>
45 
46 #include "libhammer.h"
47 
48 int
49 libhammer_pfs_get_snapshots(libhammer_fsinfo_t fip, libhammer_pfsinfo_t pip)
50 {
51 	struct hammer_snapshot_data *snapdata = NULL;
52 	struct hammer_ioc_snapshot snap;
53 	libhammer_snapinfo_t sip;
54 	libhammer_pfsinfo_t pfs0;
55 	char *path = NULL;
56 	int ret = 0;
57 	int fd;
58 	u_int i;
59 
60 	assert(pip != NULL);
61 	assert(fip != NULL);
62 
63 	/*
64 	 * Still need a path to open so, when not mounted, try
65 	 * to figure out the PFS path access in order to open(2)
66 	 * Note that this will fail for slave PFS that were created
67 	 * with pfs-slave directive since they don't have any transaction
68 	 * recorded and nlookup can't find them. For those we simply
69 	 * return the error in the head structure of libhammer_pfsinfo_t
70 	 * for the caller to handle the situation.
71 	 */
72 	pfs0 = libhammer_get_first_pfs(fip);
73 	if (pfs0 == NULL)
74 		return -1;
75 
76 	if (pip->mountedon == NULL)
77 		libhammer_pfs_canonical_path(pfs0->mountedon, pip, &path);
78 	else
79 		path = strdup(pip->mountedon);
80 
81 	if (path == NULL || (fd = open(path, O_RDONLY)) < 0) {
82 		pip->head.error = errno;
83 		ret = -1;
84 		goto out;
85 	}
86 
87 	bzero(&snap, sizeof(snap));
88 
89 	/*
90 	 * Loop while there are snapshots returned from the ioctl(2) call.
91 	 *
92 	 * For more information on how the snapshots are returned
93 	 * to userland please check sys/vfs/hammer/hammer_ioctl.c
94 	 */
95 	do {
96 		if (ioctl(fd, HAMMERIOC_GET_SNAPSHOT, &snap) < 0) {
97 			pip->head.error = errno;
98 			ret = -1;
99 			close(fd);
100 			goto out;
101 		}
102 		for (i = 0; i < snap.count; i++) {
103 			snapdata = &snap.snaps[i];
104 			sip = _libhammer_malloc(sizeof(*sip));
105 			sip->tid = snapdata->tid;
106 			sip->ts = snapdata->ts;
107 			if (strlen(snapdata->label))
108 				sprintf(sip->label, "%s", snapdata->label);
109 			else
110 				sip->label[0] = '\0';
111 			TAILQ_INSERT_TAIL(&pip->list_snap, sip, entries);
112 			pip->snapcount++;
113 		}
114 	} while (snap.head.error == 0 && snap.count);
115 	close(fd);
116 
117 out:
118 	if (path)
119 		free(path);
120 
121 	return (ret);
122 }
123 
124 void
125 libhammer_pfs_free_snapshots(libhammer_pfsinfo_t pip)
126 {
127 	struct libhammer_snapinfo *si;
128 
129 	while(!TAILQ_EMPTY(&pip->list_snap)) {
130 		si = TAILQ_FIRST(&pip->list_snap);
131 		TAILQ_REMOVE(&pip->list_snap, si, entries);
132 		free(si);
133 	}
134 }
135