LVM2 daemons/dmeventd/plugins/snapshot/dmevent ...
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CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: mornfall at sourceware.org 2010-10-15 16:28:16
Modified files:
daemons/dmeventd/plugins/snapshot: dmeventd_snapshot.c
doc : example.conf.in
lib/config : defaults.h
test : test-utils.sh
tools : commands.h lvresize.c
Added files:
test : t-lvextend-snapshot-dmeventd.sh
t-lvextend-snapshot-policy.sh
Log message:
Implement automatic snapshot extension with dmeventd, and add two new options
to lvm.conf in the activation section: 'snapshot_autoextend_threshold' and
'snapshot_autoextend_percent', that define how to handle automatic snapshot
extension. The former defines when the snapshot should be extended: when its
space usage exceeds this many percent. The latter defines how much extra space
should be allocated for the snapshot, in percent of its current size.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/dmeventd/plugins/snapshot/dmeventd_snapshot.c.diff?cvsroot=lvm2&r1=1.10&r2=1.11
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/doc/example.conf.in.diff?cvsroot=lvm2&r1=1.14&r2=1.15
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/config/defaults.h.diff?cvsroot=lvm2&r1=1.69&r2=1.70
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/test/t-lvextend-snapshot-dmeventd.sh.diff?cvsroot=lvm2&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/test/t-lvextend-snapshot-policy.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=1.51&r2=1.52
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/tools/commands.h.diff?cvsroot=lvm2&r1=1.155&r2=1.156
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/tools/lvresize.c.diff?cvsroot=lvm2&r1=1.123&r2=1.124
--- LVM2/daemons/dmeventd/plugins/snapshot/dmeventd_snapshot.c 2010/07/09 15:34:41 1.10
+++ LVM2/daemons/dmeventd/plugins/snapshot/dmeventd_snapshot.c 2010/10/15 16:28:14 1.11
@@ -26,8 +26,10 @@
/* First warning when snapshot is 80% full. */
#define WARNING_THRESH 80
-/* Further warnings at 85%, 90% and 95% fullness. */
-#define WARNING_STEP 5
+/* Run a check every 5%. */
+#define CHECK_STEP 5
+/* Do not bother checking snapshots less than 50% full. */
+#define CHECK_MINIMUM 50
struct snap_status {
int invalid;
@@ -69,6 +71,28 @@
status->max = atoi(p);
}
+static int _extend(const char *device)
+{
+ char *vg = NULL, *lv = NULL, *layer = NULL;
+ char cmd_str[1024];
+ int r = 0;
+
+ if (!dm_split_lvm_name(dmeventd_lvm2_pool(), device, &vg, &lv, &layer)) {
+ syslog(LOG_ERR, "Unable to determine VG name from %s.", device);
+ return 0;
+ }
+ if (sizeof(cmd_str) <= snprintf(cmd_str, sizeof(cmd_str),
+ "lvextend --use-policies %s/%s", vg, lv)) {
+ syslog(LOG_ERR, "Unable to form LVM command: Device name too long.");
+ return 0;
+ }
+
+ r = dmeventd_lvm2_run(cmd_str);
+ syslog(LOG_INFO, "Extension of snapshot %s/%s %s.", vg, lv,
+ (r == ECMD_PROCESSED) ? "finished successfully" : "failed");
+ return r == ECMD_PROCESSED;
+}
+
void process_event(struct dm_task *dmt,
enum dm_event_mask event __attribute__((unused)),
void **private)
@@ -79,10 +103,10 @@
char *params;
struct snap_status status = { 0 };
const char *device = dm_task_get_name(dmt);
- int percent, *percent_warning = (int*)private;
+ int percent, *percent_check = (int*)private;
/* No longer monitoring, waiting for remove */
- if (!*percent_warning)
+ if (!*percent_check)
return;
dmeventd_lvm2_lock();
@@ -92,21 +116,27 @@
goto out;
_parse_snapshot_params(params, &status);
+
/*
* If the snapshot has been invalidated or we failed to parse
* the status string. Report the full status string to syslog.
*/
if (status.invalid || !status.max) {
syslog(LOG_ERR, "Snapshot %s changed state to: %s\n", device, params);
- *percent_warning = 0;
+ *percent_check = 0;
goto out;
}
percent = 100 * status.used / status.max;
- if (percent >= *percent_warning) {
- syslog(LOG_WARNING, "Snapshot %s is now %i%% full.\n", device, percent);
- /* Print warning on the next multiple of WARNING_STEP. */
- *percent_warning = (percent / WARNING_STEP) * WARNING_STEP + WARNING_STEP;
+ if (percent >= *percent_check) {
+ /* Usage has raised more than CHECK_STEP since the last
+ time. Run actions. */
+ *percent_check = (percent / CHECK_STEP) * CHECK_STEP + CHECK_STEP;
+ if (percent >= WARNING_THRESH) /* Print a warning to syslog. */
+ syslog(LOG_WARNING, "Snapshot %s is now %i%% full.\n", device, percent);
+ /* Try to extend the snapshot, in accord with user-set policies */
+ if (!_extend(device))
+ syslog(LOG_ERR, "Failed to extend snapshot %s.", device);
}
out:
dmeventd_lvm2_unlock();
@@ -118,10 +148,10 @@
int minor __attribute__((unused)),
void **private)
{
- int *percent_warning = (int*)private;
+ int *percent_check = (int*)private;
int r = dmeventd_lvm2_init();
- *percent_warning = WARNING_THRESH; /* Print warning if snapshot is full */
+ *percent_check = CHECK_MINIMUM;
syslog(LOG_INFO, "Monitoring snapshot %s\n", device);
return r;
--- LVM2/doc/example.conf.in 2010/10/15 16:24:00 1.14
+++ LVM2/doc/example.conf.in 2010/10/15 16:28:15 1.15
@@ -428,6 +428,25 @@
mirror_log_fault_policy = "allocate"
mirror_image_fault_policy = "remove"
+ # 'snapshot_autoextend_threshold' and 'snapshot_autoextend_percent' define
+ # how to handle automatic snapshot extension. The former defines when the
+ # snapshot should be extended: when its space usage exceeds this many
+ # percent. The latter defines how much extra space should be allocated for
+ # the snapshot, in percent of its current size.
+ #
+ # For example, if you set snapshot_autoextend_threshold to 70 and
+ # snapshot_autoextend_percent to 20, whenever a snapshot exceeds 70% usage,
+ # it will be extended by another 20%. For a 1G snapshot, using up 700M will
+ # trigger a resize to 1.2G. When the usage exceeds 840M, the snapshot will
+ # be extended to 1.44G, and so on.
+ #
+ # Setting snapshot_autoextend_threshold to 100 disables automatic
+ # extensions. The minimum value is 50 (A setting below 50 will be treated
+ # as 50).
+
+ snapshot_autoextend_threshold = 100
+ snapshot_autoextend_percent = 20
+
# While activating devices, I/O to devices being (re)configured is
# suspended, and as a precaution against deadlocks, LVM2 needs to pin
# any memory it is using so it is not paged out. Groups of pages that
--- LVM2/lib/config/defaults.h 2010/10/13 15:40:39 1.69
+++ LVM2/lib/config/defaults.h 2010/10/15 16:28:15 1.70
@@ -148,5 +148,7 @@
#define DEFAULT_MIRROR_DEVICE_FAULT_POLICY "remove"
#define DEFAULT_MIRROR_LOG_FAULT_POLICY "allocate"
+#define DEFAULT_SNAPSHOT_AUTOEXTEND_THRESHOLD 100
+#define DEFAULT_SNAPSHOT_AUTOEXTEND_PERCENT 20
#endif /* _LVM_DEFAULTS_H */
/cvs/lvm2/LVM2/test/t-lvextend-snapshot-dmeventd.sh,v --> standard output
revision 1.1
--- LVM2/test/t-lvextend-snapshot-dmeventd.sh
+++ - 2010-10-15 16:28:17.556859000 +0000
@@ -0,0 +1,51 @@
+#!/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
+
+. ./test-utils.sh
+
+extend() {
+ lvextend --use-policies --config "activation { snapshot_extend_threshold = $1 }" $vg/snap
+}
+
+write() {
+ mount $DM_DEV_DIR/$vg/snap mnt
+ dd if=/dev/zero of=mnt/file$1 bs=1k count=$2
+ umount mnt
+}
+
+percent() {
+ lvs $vg/snap -o snap_percent --noheadings | cut -c4- | cut -d. -f1
+}
+
+which mkfs.ext2 || exit 200
+
+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
+
+write 1 4096
+pre=`percent`
+sleep 10 # dmeventd only checks every 10 seconds :(
+post=`percent`
+
+test $pre = $post
+write 2 5000
+pre=`percent`
+sleep 10 # dmeventd only checks every 10 seconds :(
+post=`percent`
+test $pre -gt $post
/cvs/lvm2/LVM2/test/t-lvextend-snapshot-policy.sh,v --> standard output
revision 1.1
--- LVM2/test/t-lvextend-snapshot-policy.sh
+++ - 2010-10-15 16:28:17.692973000 +0000
@@ -0,0 +1,47 @@
+#!/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
+
+. ./test-utils.sh
+
+extend() {
+ lvextend --use-policies --config "activation { snapshot_extend_threshold = $1 }" $vg/snap
+}
+
+write() {
+ mount $DM_DEV_DIR/$vg/snap mnt
+ dd if=/dev/zero of=mnt/file$1 bs=1k count=$2
+ umount mnt
+}
+
+percent() {
+ lvs $vg/snap -o snap_percent --noheadings | cut -c4- | cut -d. -f1
+}
+
+which mkfs.ext2 || exit 200
+
+aux prepare_vg 2
+lvcreate -l 8 -n base $vg
+mkfs.ext2 $DM_DEV_DIR/$vg/base
+
+lvcreate -s -l 4 -n snap $vg/base
+mkdir mnt
+
+write 1 4096
+pre=`percent`
+extend 50
+post=`percent`
+
+test $pre = $post
+write 2 4096
+pre=`percent`
+extend 50
+post=`percent`
+test $pre -gt $post
--- LVM2/test/test-utils.sh 2010/10/12 16:13:43 1.51
+++ LVM2/test/test-utils.sh 2010/10/15 16:28:15 1.52
@@ -394,6 +394,8 @@
udev_sync = 1
udev_rules = 1
polling_interval = 0
+ snapshot_autoextend_percent = 50
+ snapshot_autoextend_threshold = 50
}
EOF
# FIXME remove this workaround after mmap & truncating file problems solved
--- LVM2/tools/commands.h 2010/10/13 10:34:32 1.155
+++ LVM2/tools/commands.h 2010/10/15 16:28:16 1.156
@@ -259,6 +259,7 @@
"\t{-l|--extents [+]LogicalExtentsNumber[%{VG|LV|PVS|FREE|ORIGIN}] |\n"
"\t -L|--size [+]LogicalVolumeSize[bBsSkKmMgGtTpPeE]}\n"
"\t[-m|--mirrors Mirrors]\n"
+ "\t[--use-policies]\n"
"\t[-n|--nofsck]\n"
"\t[--noudevsync]\n"
"\t[-r|--resizefs]\n"
@@ -270,7 +271,7 @@
alloc_ARG, autobackup_ARG, extents_ARG, force_ARG, mirrors_ARG,
nofsck_ARG, noudevsync_ARG, resizefs_ARG, size_ARG, stripes_ARG,
- stripesize_ARG, test_ARG, type_ARG)
+ stripesize_ARG, test_ARG, type_ARG, use_policies_ARG)
xx(lvmchange,
"With the device mapper, this is obsolete and does nothing.",
--- LVM2/tools/lvresize.c 2010/08/17 16:25:35 1.123
+++ LVM2/tools/lvresize.c 2010/10/15 16:28:16 1.124
@@ -186,6 +186,7 @@
const char *cmd_name;
char *st;
unsigned dev_dir_found = 0;
+ int use_policy = arg_count(cmd, use_policies_ARG);
lp->sign = SIGN_NONE;
lp->resize = LV_ANY;
@@ -196,34 +197,41 @@
if (!strcmp(cmd_name, "lvextend"))
lp->resize = LV_EXTEND;
- /*
- * Allow omission of extents and size if the user has given us
- * one or more PVs. Most likely, the intent was "resize this
- * LV the best you can with these PVs"
- */
- if ((arg_count(cmd, extents_ARG) + arg_count(cmd, size_ARG) == 0) &&
- (argc >= 2)) {
- lp->extents = 100;
- lp->percent = PERCENT_PVS;
+ if (use_policy) {
+ /* do nothing; _lvresize will handle --use-policies itself */
+ lp->extents = 0;
lp->sign = SIGN_PLUS;
- } else if ((arg_count(cmd, extents_ARG) +
- arg_count(cmd, size_ARG) != 1)) {
- log_error("Please specify either size or extents but not "
- "both.");
- return 0;
- }
-
- if (arg_count(cmd, extents_ARG)) {
- lp->extents = arg_uint_value(cmd, extents_ARG, 0);
- lp->sign = arg_sign_value(cmd, extents_ARG, SIGN_NONE);
- lp->percent = arg_percent_value(cmd, extents_ARG, PERCENT_NONE);
- }
-
- /* Size returned in kilobyte units; held in sectors */
- if (arg_count(cmd, size_ARG)) {
- lp->size = arg_uint64_value(cmd, size_ARG, UINT64_C(0));
- lp->sign = arg_sign_value(cmd, size_ARG, SIGN_NONE);
- lp->percent = PERCENT_NONE;
+ lp->percent = PERCENT_LV;
+ } else {
+ /*
+ * Allow omission of extents and size if the user has given us
+ * one or more PVs. Most likely, the intent was "resize this
+ * LV the best you can with these PVs"
+ */
+ if ((arg_count(cmd, extents_ARG) + arg_count(cmd, size_ARG) == 0) &&
+ (argc >= 2)) {
+ lp->extents = 100;
+ lp->percent = PERCENT_PVS;
+ lp->sign = SIGN_PLUS;
+ } else if ((arg_count(cmd, extents_ARG) +
+ arg_count(cmd, size_ARG) != 1)) {
+ log_error("Please specify either size or extents but not "
+ "both.");
+ return 0;
+ }
+
+ if (arg_count(cmd, extents_ARG)) {
+ lp->extents = arg_uint_value(cmd, extents_ARG, 0);
+ lp->sign = arg_sign_value(cmd, extents_ARG, SIGN_NONE);
+ lp->percent = arg_percent_value(cmd, extents_ARG, PERCENT_NONE);
+ }
+
+ /* Size returned in kilobyte units; held in sectors */
+ if (arg_count(cmd, size_ARG)) {
+ lp->size = arg_uint64_value(cmd, size_ARG, 0);
+ lp->sign = arg_sign_value(cmd, size_ARG, SIGN_NONE);
+ lp->percent = PERCENT_NONE;
+ }
}
if (lp->resize == LV_EXTEND && lp->sign == SIGN_MINUS) {
@@ -269,6 +277,33 @@
return 1;
}
+static int _adjust_policy_params(struct cmd_context *cmd,
+ struct logical_volume *lv, struct lvresize_params *lp)
+{
+ float percent;
+ percent_range_t range;
+ int policy_threshold, policy_amount;
+
+ policy_threshold =
+ find_config_tree_int(cmd, "activation/snapshot_autoextend_threshold",
+ DEFAULT_SNAPSHOT_AUTOEXTEND_THRESHOLD);
+ policy_amount =
+ find_config_tree_int(cmd, "activation/snapshot_autoextend_percent",
+ DEFAULT_SNAPSHOT_AUTOEXTEND_PERCENT);
+
+ if (policy_threshold >= 100)
+ return 1; /* nothing to do */
+
+ if (!lv_snapshot_percent(lv, &percent, &range))
+ return_0;
+
+ if (range != PERCENT_0_TO_100 || percent <= policy_threshold)
+ return 1; /* nothing to do */
+
+ lp->extents = policy_amount;
+ return 1;
+}
+
static int _lvresize(struct cmd_context *cmd, struct volume_group *vg,
struct lvresize_params *lp)
{
@@ -287,6 +322,7 @@
uint32_t seg_extents;
uint32_t sz, str;
struct dm_list *pvh = NULL;
+ int use_policy = arg_count(cmd, use_policies_ARG);
/* does LV exist? */
if (!(lvl = find_lv_in_vg(vg, lp->lv_name))) {
@@ -319,6 +355,14 @@
lv = lvl->lv;
+ if (use_policy) {
+ if (!lv_is_cow(lv)) {
+ log_error("Can't use policy-based resize for non-snapshot volumes.");
+ return ECMD_FAILED;
+ }
+ _adjust_policy_params(cmd, lv, lp);
+ }
+
if (!lv_is_visible(lv)) {
log_error("Can't resize internal logical volume %s", lv->name);
return ECMD_FAILED;
@@ -404,6 +448,8 @@
}
if (lp->extents == lv->le_count) {
+ if (use_policy)
+ return ECMD_PROCESSED; /* Nothing to do. */
if (!lp->resizefs) {
log_error("New size (%d extents) matches existing size "
"(%d extents)", lp->extents, lv->le_count);