From 6d6d4459ab969cfd0b6fcb7afea1c76496f8788a Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 4 Nov 2021 17:38:13 +0100
Subject: [PATCH] homectl: add new "homectl rebalance" command

Let's add an explicit, synchronous command to request immediate rebalancing and
wait for it.
---
 man/homectl.xml    | 12 ++++++++++++
 src/home/homectl.c | 28 ++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/man/homectl.xml b/man/homectl.xml
index ca9225a1e0d..5a06346d7b6 100644
--- a/man/homectl.xml
+++ b/man/homectl.xml
@@ -946,6 +946,18 @@
         scripts and such, but requires authentication with the user's credentials in order to be able to
         unlock the user's home directory.</para></listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term><command>rebalance</command></term>
+
+        <listitem><para>Rebalance free disk space between active home areas and the backing storage. See
+        <option>--rebalance-weight=</option> above. This executes no operation unless there's at least one
+        active LUKS2 home area that has disk space rebalancing enabled. This operation is synchronous: it
+        will only complete once disk space is rebalanced according to the rebalancing weights. Note that
+        rebalancing also takes place automatically in the background in regular intervals. Use this command
+        to synchronously ensure disk space is properly redistributed before initiating an operation requiring
+        large amounts of disk space.</para></listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 
diff --git a/src/home/homectl.c b/src/home/homectl.c
index 0c69299c84f..6057c04bae8 100644
--- a/src/home/homectl.c
+++ b/src/home/homectl.c
@@ -2103,6 +2103,32 @@ static int deactivate_all_homes(int argc, char *argv[], void *userdata) {
         return 0;
 }
 
+static int rebalance(int argc, char *argv[], void *userdata) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        int r;
+
+        r = acquire_bus(&bus);
+        if (r < 0)
+                return r;
+
+        r = bus_message_new_method_call(bus, &m, bus_mgr, "Rebalance");
+        if (r < 0)
+                return bus_log_create_error(r);
+
+        r = sd_bus_call(bus, m, HOME_SLOW_BUS_CALL_TIMEOUT_USEC, &error, NULL);
+        if (r < 0) {
+                if (sd_bus_error_has_name(&error, BUS_ERROR_REBALANCE_NOT_NEEDED))
+                        log_info("No homes needed rebalancing.");
+                else
+                        return log_error_errno(r, "Failed to rebalance: %s", bus_error_message(&error, r));
+        } else
+                log_info("Completed rebalancing.");
+
+        return 0;
+}
+
 static int drop_from_identity(const char *field) {
         int r;
 
@@ -2157,6 +2183,7 @@ static int help(int argc, char *argv[], void *userdata) {
                "  unlock USER…                 Unlock a temporarily locked home area\n"
                "  lock-all                     Lock all suitable home areas\n"
                "  deactivate-all               Deactivate all active home areas\n"
+               "  rebalance                    Rebalance free space between home areas\n"
                "  with USER [COMMAND…]         Run shell or command with access to a home area\n"
                "\n%4$sOptions:%5$s\n"
                "  -h --help                    Show this help\n"
@@ -3746,6 +3773,7 @@ static int run(int argc, char *argv[]) {
                 { "with",           2,        VERB_ANY, 0,            with_home            },
                 { "lock-all",       VERB_ANY, 1,        0,            lock_all_homes       },
                 { "deactivate-all", VERB_ANY, 1,        0,            deactivate_all_homes },
+                { "rebalance",      VERB_ANY, 1,        0,            rebalance            },
                 {}
         };