lib/device/dev-cache.c | 161 ++++++++++++++++++++++++++++++++++++----------
test/shell/dev-aliases.sh | 53 +++++++++++++++
2 files changed, 179 insertions(+), 35 deletions(-)
create mode 100644 test/shell/dev-aliases.sh
diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
index d5f18ff..8082efa 100644
--- a/lib/device/dev-cache.c
+++ b/lib/device/dev-cache.c
@@ -1428,60 +1428,151 @@ struct device *dev_hash_get(const char *name)
return (struct device *) dm_hash_lookup(_cache.names, name);
}
+static void _remove_alias(struct device *dev, const char *name)
+{
+ struct dm_str_list *strl;
+
+ dm_list_iterate_items(strl, &dev->aliases) {
+ if (!strcmp(strl->str, name)) {
+ dm_list_del(&strl->list);
+ return;
+ }
+ }
+}
+
+/*
+ * Check that paths for this dev still refer to the same dev_t. This is known
+ * to drop invalid paths in the case where lvm deactivates an LV, which causes
+ * that LV path to go away, but that LV path is not removed from dev-cache (it
+ * probably should be). Later a new path to a different LV is added to
+ * dev-cache, where the new LV has the same major:minor as the previously
+ * deactivated LV. The new LV will find the existing struct dev, and that
+ * struct dev will have dev->aliases entries that refer to the name of the old
+ * deactivated LV. Those old paths are all invalid and are dropped here.
+ */
+
+static void _verify_aliases(struct device *dev, const char *newname)
+{
+ struct dm_str_list *strl, *strl2;
+ struct stat st;
+
+ dm_list_iterate_items_safe(strl, strl2, &dev->aliases) {
+ /* newname was just stat'd and added by caller */
+ if (newname && !strcmp(strl->str, newname))
+ continue;
+
+ if (stat(strl->str, &st) || (st.st_rdev != dev->dev)) {
+ log_debug("Drop invalid path %s for %d:%d (new path %s).",
+ strl->str, (int)MAJOR(dev->dev), (int)MINOR(dev->dev), newname ?: "");
+ dm_hash_remove(_cache.names, strl->str);
+ dm_list_del(&strl->list);
+ }
+ }
+}
+
struct device *dev_cache_get(struct cmd_context *cmd, const char *name, struct dev_filter *f)
{
- struct stat buf;
- struct device *d = (struct device *) dm_hash_lookup(_cache.names, name);
- int info_available = 0;
- int ret = 1;
+ struct device *dev = (struct device *) dm_hash_lookup(_cache.names, name);
+ struct stat st;
+ int ret;
- if (d && (d->flags & DEV_REGULAR))
- return d;
+ /*
+ * DEV_REGULAR means that is "dev" is actually a file, not a device.
+ * FIXME: I don't think dev-cache is used for files any more and this
+ * can be dropped?
+ */
+ if (dev && (dev->flags & DEV_REGULAR))
+ return dev;
+
+ /*
+ * The requested path is invalid, remove any dev-cache
+ * info for it.
+ */
+ if (stat(name, &st)) {
+ if (dev) {
+ log_print("Device path %s is invalid for %d:%d %s.",
+ name, (int)MAJOR(dev->dev), (int)MINOR(dev->dev), dev_name(dev));
- /* If the entry's wrong, remove it */
- if (stat(name, &buf) < 0) {
- if (d)
dm_hash_remove(_cache.names, name);
- log_sys_very_verbose("stat", name);
- d = NULL;
- } else
- info_available = 1;
- if (d && (buf.st_rdev != d->dev)) {
- dm_hash_remove(_cache.names, name);
- d = NULL;
- }
+ _remove_alias(dev, name);
- if (!d) {
- _insert(name, info_available ? &buf : NULL, 0, obtain_device_list_from_udev());
- d = (struct device *) dm_hash_lookup(_cache.names, name);
- if (!d) {
- log_debug_devs("Device name not found in dev_cache repeat dev_cache_scan for %s", name);
- dev_cache_scan();
- d = (struct device *) dm_hash_lookup(_cache.names, name);
+ /* Remove any other names in dev->aliases that are incorrect. */
+ _verify_aliases(dev, NULL);
}
+ return NULL;
}
- if (!d)
+ if (!S_ISBLK(st.st_mode)) {
+ log_debug("Not a block device %s.", name);
return NULL;
+ }
- if (d && (d->flags & DEV_REGULAR))
- return d;
+ /*
+ * dev-cache has incorrect info for the requested path.
+ * Remove incorrect info and then add new dev-cache entry.
+ */
+ if (dev && (st.st_rdev != dev->dev)) {
+ log_print("Device path %s does not match %d:%d %s.",
+ name, (int)MAJOR(dev->dev), (int)MINOR(dev->dev), dev_name(dev));
+
+ dm_hash_remove(_cache.names, name);
+
+ _remove_alias(dev, name);
+
+ /* Remove any other names in dev->aliases that are incorrect. */
+ _verify_aliases(dev, NULL);
+
+ /* Add new dev-cache entry next. */
+ dev = NULL;
+ }
+
+ /*
+ * Either add a new struct dev for st_rdev and name,
+ * or add name as a new alias for an existing struct dev
+ * for st_rdev.
+ */
+ if (!dev) {
+ _insert_dev(name, st.st_rdev);
- if (f && !(d->flags & DEV_REGULAR)) {
- ret = f->passes_filter(cmd, f, d, NULL);
+ /* Get the struct dev that was just added. */
+ dev = (struct device *) dm_hash_lookup(_cache.names, name);
- if (ret == -EAGAIN) {
- log_debug_devs("get device by name defer filter %s", dev_name(d));
- d->flags |= DEV_FILTER_AFTER_SCAN;
- ret = 1;
+ if (!dev) {
+ log_error("Failed to get device %s", name);
+ return NULL;
}
+
+ _verify_aliases(dev, name);
}
- if (f && !(d->flags & DEV_REGULAR) && !ret)
+ /*
+ * The caller passed a filter if they only want the dev if it
+ * passes filters.
+ */
+
+ if (!f)
+ return dev;
+
+ ret = f->passes_filter(cmd, f, dev, NULL);
+
+ /*
+ * This might happen if this function is called before
+ * filters can do i/o. I don't think this will happen
+ * any longer and this EAGAIN case can be removed.
+ */
+ if (ret == -EAGAIN) {
+ log_debug_devs("dev_cache_get filter deferred %s", dev_name(dev));
+ dev->flags |= DEV_FILTER_AFTER_SCAN;
+ ret = 1;
+ }
+
+ if (!ret) {
+ log_debug_devs("dev_cache_get filter excludes %s", dev_name(dev));
return NULL;
+ }
- return d;
+ return dev;
}
static struct device *_dev_cache_seek_devt(dev_t dev)
diff --git a/test/shell/dev-aliases.sh b/test/shell/dev-aliases.sh
new file mode 100644
index 0000000..c97cd5d
--- /dev/null
+++ b/test/shell/dev-aliases.sh
@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+
+# Copyright (C) 2012 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+SKIP_WITH_LVMPOLLD=1
+
+. lib/inittest
+
+aux prepare_devs 3
+
+vgcreate $vg $dev1 $dev2 $dev3
+
+#
+# This lvconvert command will deactivate LV1, then internally create a new
+# lv, lvol0, as a poolmetadataspare, then activate lvol0 to zero it.
+# lvol0 will get the same major:minor that LV1 had. When the code gets
+# the struct dev for lvol0, the new path to lvol0 is added to the
+# dev-cache with it's major:minor. That major:minor already exists in
+# dev-cache and has the stale LV1 as an alias. So the path to lvol0 is
+# added as an alias to the existing struct dev (with the correct
+# major:minor), but that struct dev has the stale LV1 path on its aliases
+# list. The code will now validate all the aliases before returning the
+# dev for lvol0, and will find that the LV1 path is stale and remove it
+# from the aliases. That will prevent the stale path from being used for
+# the dev in place of the new path.
+#
+# The preferred_name is set to /dev/mapper so that if the stale path still
+# exists, that stale path would be used as the name for the dev, and the
+# wiping code would fail to open that stale name.
+#
+
+lvcreate -n $lv1 -L32M $vg $dev1
+lvcreate -n $lv2 -L16M $vg $dev2
+lvconvert -y --type cache-pool --poolmetadata $lv2 --cachemode writeback $vg/$lv1 --config='devices { preferred_names=["/dev/mapper/"] }'
+lvremove -y $vg/$lv1
+
+lvcreate -n $lv1 -L32M $vg $dev1
+lvcreate -n $lv2 -L16M $vg $dev2
+lvconvert -y --type cache-pool --poolmetadata $lv2 $vg/$lv1
+lvremove -y $vg/$lv1
+
+# TODO: add more validation of dev aliases being specified as command
+# args in combination with various preferred_names settings.
+
+vgremove -ff $vg