daemon: Automatically reload sysroot before txn

In this PR: https://github.com/projectatomic/rpm-ostree/pull/1309
I was hitting race conditions running `ostree admin pin` then
`rpm-ostree cleanup` as it was possible that the daemon hadn't handled
the inotify on the sysroot and reloaded the deployment state before
the txn request came in.

Close this race by doing an implicit `reload` before starting a txn.
This is a pretty efficient operation because for the sysroot we're
just doing a `stat()` and comparing mtime.

Implementation wise, change the external API to drop the "did change"
boolean as nothing outside of the `sysroot.c` file used it.

A followup to this would be changing the `status` CLI to call a
(new) DBus API like `RequestReload` that at least did the sysroot
reload if the daemon was otherwise idle or so?  And it'd be available
to unprivileged users.

Closes: #1311
Approved by: cgwalters
This commit is contained in:
Colin Walters 2018-03-23 10:11:32 -04:00 committed by Atomic Bot
parent 9ddf65aade
commit 60aa9a4a33
4 changed files with 30 additions and 10 deletions

View File

@ -39,6 +39,11 @@
#include <systemd/sd-login.h>
#include <systemd/sd-journal.h>
static gboolean
sysroot_reload (RpmostreedSysroot *self,
gboolean *out_changed,
GError **error);
/**
* SECTION: sysroot
* @title: RpmostreedSysroot
@ -443,7 +448,7 @@ handle_reload_config (RPMOSTreeSysroot *object,
goto out;
gboolean sysroot_changed;
if (!rpmostreed_sysroot_reload (self, &sysroot_changed, error))
if (!sysroot_reload (self, &sysroot_changed, error))
goto out;
/* also send an UPDATED signal if configs changed to cause OS interfaces to reload; we do
@ -691,8 +696,8 @@ rpmostreed_sysroot_class_init (RpmostreedSysrootClass *klass)
gdbus_interface_skeleton_class->g_authorize_method = sysroot_authorize_method;
}
gboolean
rpmostreed_sysroot_reload (RpmostreedSysroot *self,
static gboolean
sysroot_reload (RpmostreedSysroot *self,
gboolean *out_changed,
GError **error)
{
@ -714,6 +719,12 @@ rpmostreed_sysroot_reload (RpmostreedSysroot *self,
return ret;
}
gboolean
rpmostreed_sysroot_reload (RpmostreedSysroot *self, GError **error)
{
return sysroot_reload (self, NULL, error);
}
static void
on_deploy_changed (GFileMonitor *monitor,
GFile *file,
@ -726,7 +737,7 @@ on_deploy_changed (GFileMonitor *monitor,
if (event_type == G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED)
{
if (!rpmostreed_sysroot_reload (self, NULL, &error))
if (!rpmostreed_sysroot_reload (self, &error))
goto out;
}
@ -796,6 +807,10 @@ rpmostreed_sysroot_populate (RpmostreedSysroot *self,
return TRUE;
}
/* Ensures the sysroot is up to date, and returns references to the underlying
* libostree sysroot object as well as the repo. This function should
* be used at the start of both state querying and transactions.
*/
gboolean
rpmostreed_sysroot_load_state (RpmostreedSysroot *self,
GCancellable *cancellable,
@ -803,6 +818,14 @@ rpmostreed_sysroot_load_state (RpmostreedSysroot *self,
OstreeRepo **out_repo,
GError **error)
{
/* Always do a reload check here to suppress race conditions such as
* doing: ostree admin pin && rpm-ostree cleanup
* Without this we're relying on the file monitoring picking things up.
* Note that the sysroot reload checks mtimes and hence is a cheap
* no-op if nothing has changed.
*/
if (!rpmostreed_sysroot_reload (self, error))
return FALSE;
if (out_sysroot)
*out_sysroot = g_object_ref (rpmostreed_sysroot_get_root (self));
if (out_repo)

View File

@ -36,7 +36,6 @@ gboolean rpmostreed_sysroot_populate (RpmostreedSysroot *self
GCancellable *cancellable,
GError **error);
gboolean rpmostreed_sysroot_reload (RpmostreedSysroot *self,
gboolean *out_changed,
GError **error);
OstreeSysroot * rpmostreed_sysroot_get_root (RpmostreedSysroot *self);

View File

@ -335,7 +335,7 @@ transaction_execute_done_cb (GObject *source_object,
success = g_task_propagate_boolean (G_TASK (result), &local_error);
if (success)
{
if (!rpmostreed_sysroot_reload (rpmostreed_sysroot_get (), NULL, &local_error))
if (!rpmostreed_sysroot_reload (rpmostreed_sysroot_get (), &local_error))
success = FALSE;
}

View File

@ -126,11 +126,9 @@ assert_not_file_has_content status.txt "Pinned: yes"
echo "ok pinning"
vm_cmd ostree admin pin 0
vm_rpmostree reload # Try to avoid reload races
vm_rpmostree cleanup -p
vm_assert_status_jq ".deployments|length == 2"
vm_cmd ostree admin pin -u 0
vm_rpmostree reload # Try to avoid reload races
vm_rpmostree cleanup -p
vm_assert_status_jq ".deployments|length == 1"
echo "ok pinned retained"