[lvm-devel] LVM2 daemons/dmeventd/plugins/snapshot/dmevent ...
mornfall at sourceware.org
mornfall at sourceware.org
Fri Oct 29 16:43:53 UTC 2010
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: mornfall at sourceware.org 2010-10-29 16:43:52
Modified files:
daemons/dmeventd/plugins/snapshot: dmeventd_snapshot.c
test : test-utils.sh
Added files:
test : t-snapshot-autoumount-dmeventd.sh
Log message:
Add code to the dmeventd snapshot plugin to automatically unmount snapshots
that have been invalidated.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/dmeventd/plugins/snapshot/dmeventd_snapshot.c.diff?cvsroot=lvm2&r1=1.11&r2=1.12
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/test/t-snapshot-autoumount-dmeventd.sh.diff?cvsroot=lvm2&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/test/test-utils.sh.diff?cvsroot=lvm2&r1=1.54&r2=1.55
--- LVM2/daemons/dmeventd/plugins/snapshot/dmeventd_snapshot.c 2010/10/15 16:28:14 1.11
+++ LVM2/daemons/dmeventd/plugins/snapshot/dmeventd_snapshot.c 2010/10/29 16:43:51 1.12
@@ -21,6 +21,7 @@
#include "lvm-string.h"
+#include <sys/wait.h>
#include <syslog.h> /* FIXME Replace syslog with multilog */
/* FIXME Missing openlog? */
@@ -31,6 +32,8 @@
/* Do not bother checking snapshots less than 50% full. */
#define CHECK_MINIMUM 50
+#define UMOUNT_COMMAND "/bin/umount"
+
struct snap_status {
int invalid;
int used;
@@ -71,6 +74,47 @@
status->max = atoi(p);
}
+static int _run(const char *cmd, ...)
+{
+ va_list ap;
+ int argc = 1; /* for argv[0], i.e. cmd */
+ int i = 0;
+ const char **argv;
+ pid_t pid = fork();
+ int status;
+
+ if (pid == 0) { /* child */
+ va_start(ap, cmd);
+ while (va_arg(ap, const char *))
+ ++ argc;
+ va_end(ap);
+
+ /* + 1 for the terminating NULL */
+ argv = alloca(sizeof(const char *) * (argc + 1));
+
+ argv[0] = cmd;
+ va_start(ap, cmd);
+ while ((argv[++i] = va_arg(ap, const char *)));
+ va_end(ap);
+
+ execvp(cmd, (char **)argv);
+ syslog(LOG_ERR, "Failed to execute %s: %s.\n", cmd, strerror(errno));
+ exit(127);
+ }
+
+ if (pid > 0) { /* parent */
+ if (waitpid(pid, &status, 0) != pid)
+ return 0; /* waitpid failed */
+ if (!WIFEXITED(status) || WEXITSTATUS(status))
+ return 0; /* the child failed */
+ }
+
+ if (pid < 0)
+ return 0; /* fork failed */
+
+ return 1; /* all good */
+}
+
static int _extend(const char *device)
{
char *vg = NULL, *lv = NULL, *layer = NULL;
@@ -93,6 +137,41 @@
return r == ECMD_PROCESSED;
}
+static void _umount(const char *device, int major, int minor)
+{
+ FILE *mounts;
+ char buffer[4096];
+ char *words[3];
+ struct stat st;
+
+ if (!(mounts = fopen("/proc/mounts", "r"))) {
+ syslog(LOG_ERR, "Could not read /proc/mounts. Not umounting %s.\n", device);
+ return;
+ }
+
+ while (!feof(mounts)) {
+ /* read a line of /proc/mounts */
+ if (!fgets(buffer, sizeof(buffer), mounts))
+ break; /* eof, likely */
+
+ /* words[0] is the mount point and words[1] is the device path */
+ dm_split_words(buffer, 3, 0, words);
+
+ /* find the major/minor of the device */
+ if (stat(words[0], &st))
+ continue; /* can't stat, skip this one */
+
+ if (S_ISBLK(st.st_mode) &&
+ major(st.st_rdev) == major &&
+ minor(st.st_rdev) == minor) {
+ syslog(LOG_ERR, "Unmounting invalid snapshot %s from %s.", device, words[1]);
+ if (!_run(UMOUNT_COMMAND, "-fl", words[1], NULL))
+ syslog(LOG_ERR, "Failed to umount snapshot %s from %s: %s.",
+ device, words[1], strerror(errno));
+ }
+ }
+}
+
void process_event(struct dm_task *dmt,
enum dm_event_mask event __attribute__((unused)),
void **private)
@@ -117,6 +196,16 @@
_parse_snapshot_params(params, &status);
+ if (status.invalid) {
+ syslog(LOG_ERR, "Trying to umount invalid snapshot %s...\n", device);
+ struct dm_info info;
+ if (dm_task_get_info(dmt, &info)) {
+ dmeventd_lvm2_unlock();
+ _umount(device, info.major, info.minor);
+ return;
+ } /* else; too bad, but this is best-effort thing... */
+ }
+
/*
* If the snapshot has been invalidated or we failed to parse
* the status string. Report the full status string to syslog.
/cvs/lvm2/LVM2/test/t-snapshot-autoumount-dmeventd.sh,v --> standard output
revision 1.1
--- LVM2/test/t-snapshot-autoumount-dmeventd.sh
+++ - 2010-10-29 16:43:52.931121000 +0000
@@ -0,0 +1,41 @@
+#!/bin/bash
+# Copyright (C) 2010 Red Hat, Inc. All rights reserved.
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions
+# of the GNU General Public License v.2.
+#
+# 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 02111-1307 USA
+
+# no automatic extensions please
+LVM_TEST_CONFIG_SNAPSHOT_AUTOEXTEND="
+ snapshot_autoextend_percent = 0
+ snapshot_autoextend_threshold = 100"
+
+. ./test-utils.sh
+
+which mkfs.ext2 || exit 200
+
+prepare_lvmconf
+
+aux prepare_vg 2
+aux prepare_dmeventd
+
+lvcreate -l 8 -n base $vg
+mkfs.ext2 $DM_DEV_DIR/$vg/base
+
+lvcreate -s -l 4 -n snap $vg/base
+lvchange --monitor y $vg/snap
+
+mkdir mnt
+mount $DM_DEV_DIR/$vg/snap mnt
+mount
+cat /proc/mounts | grep $vg-snap
+
+dd if=/dev/zero of=mnt/file$1 bs=1M count=17
+sync
+sleep 10 # dmeventd only checks every 10 seconds :(
+
+cat /proc/mounts | not grep $vg-snap
--- LVM2/test/test-utils.sh 2010/10/26 01:25:46 1.54
+++ LVM2/test/test-utils.sh 2010/10/29 16:43:52 1.55
@@ -121,6 +121,7 @@
init_udev_transaction
while dmsetup table | grep -q ^$PREFIX; do
for s in `dmsetup info -c -o name --noheading | grep ^$PREFIX`; do
+ umount -fl $DM_DEV_DIR/mapper/$s || true
dmsetup remove $s >& /dev/null || true
done
done
@@ -360,6 +361,11 @@
test -z "$filter" && \
filter='[ "a/dev\/mirror/", "a/dev\/mapper\/.*pv[0-9_]*$/", "r/.*/" ]'
locktype=
+ if test -z "$LVM_TEST_CONFIG_SNAPSHOT_AUTOEXTEND"; then
+ LVM_TEST_CONFIG_SNAPSHOT_AUTOEXTEND="
+ snapshot_autoextend_percent = 50
+ snapshot_autoextend_threshold = 50"
+ fi
if test -n "$LVM_TEST_LOCKING"; then locktype="locking_type = $LVM_TEST_LOCKING"; fi
cat > $TESTDIR/etc/lvm.conf.new <<-EOF
$LVM_TEST_CONFIG
@@ -395,8 +401,7 @@
udev_sync = 1
udev_rules = 1
polling_interval = 0
- snapshot_autoextend_percent = 50
- snapshot_autoextend_threshold = 50
+ $LVM_TEST_CONFIG_SNAPSHOT_AUTOEXTEND
}
EOF
# FIXME remove this workaround after mmap & truncating file problems solved
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