lib/libhammer/snapshot.c

   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 }