Merge branch 'master' into rm_hook

diff --git a/dss.c b/dss.c
index 3bfcfe77b62abbd898d6bc6c8f09148ba5e5c564..6dbe11f6ba7e5fd3541a0364228b6fc81562b793 100644 (file)
--- a/dss.c
+++ b/dss.c
@@ -44,8 +44,8 @@ static int signal_pipe;
 static pid_t create_pid;
 /** Whether the pre-create-hook/rsync/post-create-hook is currently stopped. */
 static int create_process_stopped;
-/** Process id of current rm process. */
-static pid_t rm_pid;
+/** Process id of current pre-remove/rm/post-remove process. */
+static pid_t remove_pid;
 /** When the next snapshot is due. */
 static struct timeval next_snapshot_time;
 /** Creation time of the snapshot currently being created. */
@@ -54,6 +54,8 @@ static int64_t current_snapshot_creation_time;
 static char *path_to_last_complete_snapshot;
 /** \sa \ref snap.h for details. */
 static unsigned snapshot_creation_status;
+/** \sa \ref snap.h for details. */
+static unsigned snapshot_removal_status;
 
 
 DEFINE_DSS_ERRLIST;
@@ -191,7 +193,7 @@ out:
 static int remove_snapshot(struct snapshot *s, char *why)
 {
        int fds[3] = {0, 0, 0};
-       assert(!rm_pid);
+       assert(!remove_pid);
        char *new_name = being_deleted_name(s);
        int ret = dss_rename(s->name, new_name);
        char *argv[] = {"rm", "-rf", new_name, NULL};
@@ -200,7 +202,7 @@ static int remove_snapshot(struct snapshot *s, char *why)
                goto out;
        DSS_NOTICE_LOG("removing %s snapshot %s (interval = %i)\n",
                why, s->name, s->interval);
-       ret = dss_exec(&rm_pid, argv[0], argv, fds);
+       ret = dss_exec(&remove_pid, argv[0], argv, fds);
 out:
        free(new_name);
        return ret;
@@ -474,7 +476,7 @@ static int wait_for_process(pid_t pid, int *status)
 
 static int handle_rm_exit(int status)
 {
-       rm_pid = 0;
+       remove_pid = 0;
        if (!WIFEXITED(status))
                return -E_INVOLUNTARY_EXIT;
        if (WEXITSTATUS(status))
@@ -484,7 +486,7 @@ static int handle_rm_exit(int status)
 
 static int wait_for_rm_process(void)
 {
-       int status, ret = wait_for_process(rm_pid, &status);
+       int status, ret = wait_for_process(remove_pid, &status);
 
        if (ret < 0)
                return ret;
@@ -585,7 +587,7 @@ static int handle_sigchld(void)
                        return -E_BUG;
                }
        }
-       if (pid == rm_pid)
+       if (pid == remove_pid)
                return handle_rm_exit(status);
        DSS_EMERG_LOG("BUG: unknown process %d died\n", (int)pid);
        return -E_BUG;
@@ -709,7 +711,7 @@ static int handle_signal(void)
        case SIGTERM:
                restart_create_process();
                kill_process(create_pid);
-               kill_process(rm_pid);
+               kill_process(remove_pid);
                ret = -E_SIGNAL;
                break;
        case SIGHUP:
@@ -815,7 +817,7 @@ static int select_loop(void)
                int low_disk_space;
                struct timeval now, *tvp;
 
-               if (rm_pid)
+               if (remove_pid)
                        tvp = NULL; /* sleep until rm process dies */
                else { /* sleep one minute */
                        tv.tv_sec = 60;
@@ -833,7 +835,7 @@ static int select_loop(void)
                        if (ret < 0)
                                goto out;
                }
-               if (rm_pid)
+               if (remove_pid)
                        continue;
                ret = disk_space_low();
                if (ret < 0)
@@ -842,7 +844,7 @@ static int select_loop(void)
                ret = try_to_free_disk_space(low_disk_space);
                if (ret < 0)
                        goto out;
-               if (rm_pid) {
+               if (remove_pid) {
                        stop_create_process();
                        continue;
                }

diff --git a/dss.ggo b/dss.ggo
index 099df4cd163765da66e2ba7eb1dca26789af1ed4..9c687f42d575606cdb852bf7b829e4def7d64edf 100644 (file)
--- a/dss.ggo
+++ b/dss.ggo
@@ -277,6 +277,37 @@ details="
        store them in a database for further analysis.
 "
 
+option "pre-remove-hook" -
+#~~~~~~~~~~~~~~~~~~~~~~~~~~
+"Executed before snapshot removal"
+string typestr="command"
+optional
+details="
+       Execute this command before removing a snapshot. If this
+       command returns with a non-zero exit status, no snapshot is
+       being removed and the operation is retried later.
+
+       For example, one might want to execute a script that checks
+       whether the snapshot to be deleted is currently used by
+       another process, e.g. by a tape-based backup system that runs
+       concurrently to dss.
+
+       Another possible application of this is to record disk-usage
+       patterns before and after snapshot removal.
+"
+
+option "post-remove-hook" -
+#~~~~~~~~~~~~~~~~~~~~~~~~~~
+"Executed after snapshot removal"
+string typestr="command"
+optional
+details="
+       Execute this after a snapshot has successfully been
+       removed. The full path of the removed snapshot is
+       passed to the hook as the first argument. The exit code of
+       this hook is ignored.
+"
+
 option "exit-hook" e
 #~~~~~~~~~~~~~~~~~~~
 "Executed if run command exits"

diff --git a/snap.h b/snap.h
index afac5e9554ab6eae991e796bbf386bddb82d8540..7ac951fc313adb9f0867bc90463d4773f215adb9 100644 (file)
--- a/snap.h
+++ b/snap.h
@@ -22,6 +22,20 @@ enum {
        SCS_POST_HOOK_RUNNING,
 };
 
+/** The state of snapshot removal. */
+enum {
+       /** No snapshot is currently being removed. */
+       SRS_READY,
+       /** The pre-removal hook has been started. */
+       SRS_PRE_HOOK_RUNNING,
+       /** The pre-remove hook failed, we're waiting to execute it again. */
+       SRS_PRE_HOOK_FAILURE,
+       /** The rm command is currently executing. */
+       SRS_RM_RUNNING,
+       /** The post-remove hook ist running. */
+       SRS_POST_HOOK_RUNNING,
+};
+
 /**
  * The status of a snapshot.
  *