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Message-Id: <1317675513-12745-2-git-send-email-philipp.reisner@linbit.com>
Date: Mon, 3 Oct 2011 22:58:24 +0200
From: Philipp Reisner <philipp.reisner@...bit.com>
To: linux-kernel@...r.kernel.org, Jens Axboe <axboe@...nel.dk>
Cc: drbd-dev@...ts.linbit.com
Subject: [PATCH 01/10] drbd: allow status dump request all volumes of a specific resource
From: Lars Ellenberg <lars.ellenberg@...bit.com>
We had drbd_adm_get_status (one single volume),
and drbd_adm_get_status_all (dump of all volumes of all resources).
This enhances the latter to be able to dump all volumes
of just one specific resource.
Signed-off-by: Philipp Reisner <philipp.reisner@...bit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@...bit.com>
---
drivers/block/drbd/drbd_nl.c | 70 +++++++++++++++++++++++++++++++++++++++--
1 files changed, 66 insertions(+), 4 deletions(-)
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 77c0249..0b6b5d8 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -2647,7 +2647,7 @@ out:
return 0;
}
-int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb)
+int get_one_status(struct sk_buff *skb, struct netlink_callback *cb)
{
struct drbd_conf *mdev;
struct drbd_genlmsghdr *dh;
@@ -2665,6 +2665,9 @@ int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb)
* where tconn is cb->args[0];
* and i is cb->args[1];
*
+ * cb->args[2] indicates if we shall loop over all resources,
+ * or just dump all volumes of a single resource.
+ *
* This may miss entries inserted after this dump started,
* or entries deleted before they are reached.
*
@@ -2675,7 +2678,6 @@ int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb)
/* synchronize with drbd_new_tconn/drbd_free_tconn */
down_read(&drbd_cfg_rwsem);
-next_tconn:
/* revalidate iterator position */
list_for_each_entry(tmp, &drbd_tconns, all_tconn) {
if (pos == NULL) {
@@ -2690,16 +2692,22 @@ next_tconn:
}
}
if (tconn) {
+next_tconn:
mdev = idr_get_next(&tconn->volumes, &volume);
if (!mdev) {
/* No more volumes to dump on this tconn.
* Advance tconn iterator. */
pos = list_entry(tconn->all_tconn.next,
struct drbd_tconn, all_tconn);
- /* But, did we dump any volume on this tconn yet? */
+ /* Did we dump any volume on this tconn yet? */
if (volume != 0) {
- tconn = NULL;
+ /* If we reached the end of the list,
+ * or only a single resource dump was requested,
+ * we are done. */
+ if (&pos->all_tconn == &drbd_tconns || cb->args[2])
+ goto out;
volume = 0;
+ tconn = pos;
goto next_tconn;
}
}
@@ -2747,6 +2755,60 @@ out:
return skb->len;
}
+/*
+ * Request status of all resources, or of all volumes within a single resource.
+ *
+ * This is a dump, as the answer may not fit in a single reply skb otherwise.
+ * Which means we cannot use the family->attrbuf or other such members, because
+ * dump is NOT protected by the genl_lock(). During dump, we only have access
+ * to the incoming skb, and need to opencode "parsing" of the nlattr payload.
+ *
+ * Once things are setup properly, we call into get_one_status().
+ */
+int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ const unsigned hdrlen = GENL_HDRLEN + GENL_MAGIC_FAMILY_HDRSZ;
+ struct nlattr *nla;
+ const char *conn_name;
+ struct drbd_tconn *tconn;
+
+ /* Is this a followup call? */
+ if (cb->args[0]) {
+ /* ... of a single resource dump,
+ * and the resource iterator has been advanced already? */
+ if (cb->args[2] && cb->args[2] != cb->args[0])
+ return 0; /* DONE. */
+ goto dump;
+ }
+
+ /* First call (from netlink_dump_start). We need to figure out
+ * which resource(s) the user wants us to dump. */
+ nla = nla_find(nlmsg_attrdata(cb->nlh, hdrlen),
+ nlmsg_attrlen(cb->nlh, hdrlen),
+ DRBD_NLA_CFG_CONTEXT);
+
+ /* No explicit context given. Dump all. */
+ if (!nla)
+ goto dump;
+ nla = nla_find_nested(nla, __nla_type(T_ctx_conn_name));
+ /* context given, but no name present? */
+ if (!nla)
+ return -EINVAL;
+ conn_name = nla_data(nla);
+ tconn = conn_by_name(conn_name);
+ if (!tconn)
+ return -ENODEV;
+
+ /* prime iterators, and set "filter" mode mark:
+ * only dump this tconn. */
+ cb->args[0] = (long)tconn;
+ /* cb->args[1] = 0; passed in this way. */
+ cb->args[2] = (long)tconn;
+
+dump:
+ return get_one_status(skb, cb);
+}
+
int drbd_adm_get_timeout_type(struct sk_buff *skb, struct genl_info *info)
{
enum drbd_ret_code retcode;
--
1.7.4.1
--
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