[PATCH 106/118] drbd: Extracted is_valid_transition() out of sanitize_state()

Philipp Reisner
2011-08-25T15:13:34Z

drivers/block/drbd/drbd_state.c | 71 +++++++++++++++++++++++++++------------
1 files changed, 49 insertions(+), 22 deletions(-)

diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index d577715..3199bf9 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -47,6 +47,7 @@ static void after_conn_state_ch(struct drbd_tconn *tconn, union drbd_state os,
union drbd_state ns, enum chg_state_flags flags);
static enum drbd_state_rv is_valid_state(struct drbd_conf *, union drbd_state);
static enum drbd_state_rv is_valid_soft_transition(union drbd_state, union drbd_state);
+static enum drbd_state_rv is_valid_transition(union drbd_state os, union drbd_state ns);
static union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state os,
union drbd_state ns, const char **warn_sync_abort);

@@ -112,15 +113,17 @@ _req_st_cond(struct drbd_conf *mdev, union drbd_state mask,
if (test_and_clear_bit(CL_ST_CHG_FAIL, &mdev->flags))
return SS_CW_FAILED_BY_PEER;

- rv = 0;
spin_lock_irqsave(&mdev->tconn->req_lock, flags);
os = mdev->state;
ns.i = (os.i & ~mask.i) | val.i;
ns = sanitize_state(mdev, os, ns, NULL);
+ rv = is_valid_transition(os, ns);
+ if (rv == SS_SUCCESS)
+ rv = SS_UNKNOWN_ERROR; /* cont waiting, otherwise fail. */

if (!cl_wide_st_chg(mdev, os, ns))
rv = SS_CW_NO_NEED;
- if (!rv) {
+ if (rv == SS_UNKNOWN_ERROR) {
rv = is_valid_state(mdev, ns);
if (rv == SS_SUCCESS) {
rv = is_valid_soft_transition(os, ns);
@@ -160,8 +163,10 @@ drbd_req_state(struct drbd_conf *mdev, union drbd_state mask,
spin_lock_irqsave(&mdev->tconn->req_lock, flags);
os = mdev->state;
ns.i = (os.i & ~mask.i) | val.i;
-
ns = sanitize_state(mdev, os, ns, NULL);
+ rv = is_valid_transition(os, ns);
+ if (rv < SS_SUCCESS)
+ goto abort;

if (cl_wide_st_chg(mdev, os, ns)) {
rv = is_valid_state(mdev, ns);
@@ -340,6 +345,8 @@ is_valid_state(struct drbd_conf *mdev, union drbd_state ns)

/**
* is_valid_soft_transition() - Returns an SS_ error code if the state transition is not possible
+ * This function limits state transitions that may be declined by DRBD. I.e.
+ * user requests (aka soft transitions).
* @mdev: DRBD device.
* @ns: new state.
* @os: old state.
@@ -390,6 +397,40 @@ is_valid_soft_transition(union drbd_state os, union drbd_state ns)
}

/**
+ * is_valid_transition() - Returns an SS_ error code if the state transition is not possible
+ * This limits hard state transitions. Hard state transitions are facts there are
+ * imposed on DRBD by the environment. E.g. disk broke or network broke down.
+ * But those hard state transitions are still not allowed to do everything.
+ * @ns: new state.
+ * @os: old state.
+ */
+static enum drbd_state_rv
+is_valid_transition(union drbd_state os, union drbd_state ns)
+{
+ enum drbd_state_rv rv = SS_SUCCESS;
+
+ /* Disallow Network errors to configure a device's network part */
+ if ((ns.conn >= C_TIMEOUT && ns.conn <= C_TEAR_DOWN) &&
+ os.conn <= C_DISCONNECTING)
+ rv = SS_NEED_CONNECTION;
+
+ /* After a network error only C_UNCONNECTED or C_DISCONNECTING may follow. */
+ if (os.conn >= C_TIMEOUT && os.conn <= C_TEAR_DOWN &&
+ ns.conn != C_UNCONNECTED && ns.conn != C_DISCONNECTING)
+ rv = SS_IN_TRANSIENT_STATE;
+
+ /* After C_DISCONNECTING only C_STANDALONE may follow */
+ if (os.conn == C_DISCONNECTING && ns.conn != C_STANDALONE)
+ rv = SS_IN_TRANSIENT_STATE;
+
+ /* we cannot fail (again) if we already detached */
+ if (ns.disk == D_FAILED && os.disk == D_DISKLESS)
+ rv = SS_IS_DISKLESS;
+
+ return rv;
+}
+
+/**
* sanitize_state() - Resolves implicitly necessary additional changes to a state transition
* @mdev: DRBD device.
* @os: old state.
@@ -411,30 +452,12 @@ static union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state
put_ldev(mdev);
}

- /* Disallow Network errors to configure a device's network part */
- if ((ns.conn >= C_TIMEOUT && ns.conn <= C_TEAR_DOWN) &&
- os.conn <= C_DISCONNECTING)
- ns.conn = os.conn;
-
- /* After a network error (+C_TEAR_DOWN) only C_UNCONNECTED or C_DISCONNECTING can follow.
- * If you try to go into some Sync* state, that shall fail (elsewhere). */
- if (os.conn >= C_TIMEOUT && os.conn <= C_TEAR_DOWN &&
- ns.conn != C_UNCONNECTED && ns.conn != C_DISCONNECTING && ns.conn <= C_TEAR_DOWN)
- ns.conn = os.conn;
-
- /* we cannot fail (again) if we already detached */
- if (ns.disk == D_FAILED && os.disk == D_DISKLESS)
- ns.disk = D_DISKLESS;
-
/* if we are only D_ATTACHING yet,
* we can (and should) go directly to D_DISKLESS. */
if (ns.disk == D_FAILED && os.disk == D_ATTACHING)
ns.disk = D_DISKLESS;

- /* After C_DISCONNECTING only C_STANDALONE may follow */
- if (os.conn == C_DISCONNECTING && ns.conn != C_STANDALONE)
- ns.conn = os.conn;
-
+ /* Implications from connection to peer and peer_isp */
if (ns.conn < C_CONNECTED) {
ns.peer_isp = 0;
ns.peer = R_UNKNOWN;
@@ -641,6 +664,10 @@ __drbd_set_state(struct drbd_conf *mdev, union drbd_state ns,
if (ns.i == os.i)
return SS_NOTHING_TO_DO;

+ rv = is_valid_transition(os, ns);
+ if (rv < SS_SUCCESS)
+ return rv;
+
if (!(flags & CS_HARD)) {
/* pre-state-change checks ; only look at ns */
/* See drbd_state_sw_errors in drbd_strings.c */
--
1.7.4.1