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drbd: Extracted is_valid_transition() out of sanitize_state() 

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Philipp Reisner 2011-02-09 16:29:33 +01:00
parent a75f34ad0c
commit 3509502dc8
1 changed files with 49 additions and 22 deletions
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71
drivers/block/drbd/drbd_state.c
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@ -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.
@ -389,6 +396,40 @@ is_valid_soft_transition(union drbd_state os, union drbd_state ns)
return rv;
}
/**
* 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.
@ -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 */