drbd: Moved the state functions into its own source file
authorPhilipp Reisner <philipp.reisner@linbit.com>
Thu, 27 Jan 2011 13:07:51 +0000 (14:07 +0100)
committerPhilipp Reisner <philipp.reisner@linbit.com>
Wed, 28 Sep 2011 08:26:43 +0000 (10:26 +0200)
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
drivers/block/drbd/Makefile
drivers/block/drbd/drbd_int.h
drivers/block/drbd/drbd_main.c
drivers/block/drbd/drbd_state.c [new file with mode: 0644]
drivers/block/drbd/drbd_state.h [new file with mode: 0644]

index cacbb04f285d97cd1281467e62f4e935ec9f72b8..06fb4453734c5df1df6494567e68c3156f53be92 100644 (file)
@@ -1,6 +1,6 @@
 drbd-y := drbd_bitmap.o drbd_proc.o
 drbd-y += drbd_worker.o drbd_receiver.o drbd_req.o drbd_actlog.o
 drbd-y += drbd_main.o drbd_strings.o drbd_nl.o
-drbd-y += drbd_interval.o
+drbd-y += drbd_interval.o drbd_state.o
 
 obj-$(CONFIG_BLK_DEV_DRBD)     += drbd.o
index 302ccc6d94324ded461775c2ba466bea20c460a5..98addab2c9289103b86206716cc4064b73a56690 100644 (file)
@@ -43,6 +43,8 @@
 #include <net/tcp.h>
 #include <linux/lru_cache.h>
 #include <linux/prefetch.h>
+#include <linux/drbd.h>
+#include "drbd_state.h"
 
 #ifdef __CHECKER__
 # define __protected_by(x)       __attribute__((require_context(x,1,999,"rdwr")))
@@ -1120,35 +1122,12 @@ static inline void drbd_put_data_sock(struct drbd_conf *mdev)
 
 /* drbd_main.c */
 
-enum chg_state_flags {
-       CS_HARD = 1,
-       CS_VERBOSE = 2,
-       CS_WAIT_COMPLETE = 4,
-       CS_SERIALIZE    = 8,
-       CS_ORDERED      = CS_WAIT_COMPLETE + CS_SERIALIZE,
-};
-
 enum dds_flags {
        DDSF_FORCED    = 1,
        DDSF_NO_RESYNC = 2, /* Do not run a resync for the new space */
 };
 
 extern void drbd_init_set_defaults(struct drbd_conf *mdev);
-extern enum drbd_state_rv drbd_change_state(struct drbd_conf *mdev,
-                                           enum chg_state_flags f,
-                                           union drbd_state mask,
-                                           union drbd_state val);
-extern void drbd_force_state(struct drbd_conf *, union drbd_state,
-                       union drbd_state);
-extern enum drbd_state_rv _drbd_request_state(struct drbd_conf *,
-                                             union drbd_state,
-                                             union drbd_state,
-                                             enum chg_state_flags);
-extern enum drbd_state_rv __drbd_set_state(struct drbd_conf *, union drbd_state,
-                                          enum chg_state_flags,
-                                          struct completion *done);
-extern void print_st_err(struct drbd_conf *, union drbd_state,
-                       union drbd_state, int);
 extern int  drbd_thread_start(struct drbd_thread *thi);
 extern void _drbd_thread_stop(struct drbd_thread *thi, int restart, int wait);
 #ifdef CONFIG_SMP
@@ -1712,6 +1691,10 @@ static inline int drbd_ee_has_active_page(struct drbd_peer_request *peer_req)
 }
 
 
+
+
+
+
 static inline void drbd_state_lock(struct drbd_conf *mdev)
 {
        wait_event(mdev->misc_wait,
@@ -1737,23 +1720,6 @@ _drbd_set_state(struct drbd_conf *mdev, union drbd_state ns,
        return rv;
 }
 
-/**
- * drbd_request_state() - Reqest a state change
- * @mdev:      DRBD device.
- * @mask:      mask of state bits to change.
- * @val:       value of new state bits.
- *
- * This is the most graceful way of requesting a state change. It is verbose
- * quite verbose in case the state change is not possible, and all those
- * state changes are globally serialized.
- */
-static inline int drbd_request_state(struct drbd_conf *mdev,
-                                    union drbd_state mask,
-                                    union drbd_state val)
-{
-       return _drbd_request_state(mdev, mask, val, CS_VERBOSE + CS_ORDERED);
-}
-
 #define __drbd_chk_io_error(m,f) __drbd_chk_io_error_(m,f, __func__)
 static inline void __drbd_chk_io_error_(struct drbd_conf *mdev, int forcedetach, const char *where)
 {
index 7728d161340660ccc48641121262a0e194655b17..4b39b3d0dd557e0fc9eaac8fb9c4a6cafa2381bf 100644 (file)
 
 #include "drbd_vli.h"
 
-struct after_state_chg_work {
-       struct drbd_work w;
-       union drbd_state os;
-       union drbd_state ns;
-       enum chg_state_flags flags;
-       struct completion *done;
-};
-
 static DEFINE_MUTEX(drbd_main_mutex);
 int drbdd_init(struct drbd_thread *);
 int drbd_worker(struct drbd_thread *);
@@ -72,9 +64,6 @@ int drbd_asender(struct drbd_thread *);
 int drbd_init(void);
 static int drbd_open(struct block_device *bdev, fmode_t mode);
 static int drbd_release(struct gendisk *gd, fmode_t mode);
-static int w_after_state_ch(struct drbd_conf *mdev, struct drbd_work *w, int unused);
-static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
-                          union drbd_state ns, enum chg_state_flags flags);
 static int w_md_sync(struct drbd_conf *mdev, struct drbd_work *w, int unused);
 static void md_sync_timer_fn(unsigned long data);
 static int w_bitmap_io(struct drbd_conf *mdev, struct drbd_work *w, int unused);
@@ -340,7 +329,7 @@ bail:
  * @what might be one of CONNECTION_LOST_WHILE_PENDING, RESEND, FAIL_FROZEN_DISK_IO,
  * RESTART_FROZEN_DISK_IO.
  */
-static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what)
+void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what)
 {
        struct drbd_tl_epoch *b, *tmp, **pn;
        struct list_head *le, *tle, carry_reads;
@@ -450,1172 +439,6 @@ void tl_restart(struct drbd_conf *mdev, enum drbd_req_event what)
        spin_unlock_irq(&mdev->tconn->req_lock);
 }
 
-/**
- * cl_wide_st_chg() - true if the state change is a cluster wide one
- * @mdev:      DRBD device.
- * @os:                old (current) state.
- * @ns:                new (wanted) state.
- */
-static int cl_wide_st_chg(struct drbd_conf *mdev,
-                         union drbd_state os, union drbd_state ns)
-{
-       return (os.conn >= C_CONNECTED && ns.conn >= C_CONNECTED &&
-                ((os.role != R_PRIMARY && ns.role == R_PRIMARY) ||
-                 (os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
-                 (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S) ||
-                 (os.disk != D_DISKLESS && ns.disk == D_DISKLESS))) ||
-               (os.conn >= C_CONNECTED && ns.conn == C_DISCONNECTING) ||
-               (os.conn == C_CONNECTED && ns.conn == C_VERIFY_S);
-}
-
-enum drbd_state_rv
-drbd_change_state(struct drbd_conf *mdev, enum chg_state_flags f,
-                 union drbd_state mask, union drbd_state val)
-{
-       unsigned long flags;
-       union drbd_state os, ns;
-       enum drbd_state_rv rv;
-
-       spin_lock_irqsave(&mdev->tconn->req_lock, flags);
-       os = mdev->state;
-       ns.i = (os.i & ~mask.i) | val.i;
-       rv = _drbd_set_state(mdev, ns, f, NULL);
-       ns = mdev->state;
-       spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
-
-       return rv;
-}
-
-/**
- * drbd_force_state() - Impose a change which happens outside our control on our state
- * @mdev:      DRBD device.
- * @mask:      mask of state bits to change.
- * @val:       value of new state bits.
- */
-void drbd_force_state(struct drbd_conf *mdev,
-       union drbd_state mask, union drbd_state val)
-{
-       drbd_change_state(mdev, CS_HARD, mask, val);
-}
-
-static enum drbd_state_rv is_valid_state(struct drbd_conf *, union drbd_state);
-static enum drbd_state_rv is_valid_state_transition(struct drbd_conf *,
-                                                   union drbd_state,
-                                                   union drbd_state);
-static union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state os,
-                                      union drbd_state ns, const char **warn_sync_abort);
-int drbd_send_state_req(struct drbd_conf *,
-                       union drbd_state, union drbd_state);
-
-static enum drbd_state_rv
-_req_st_cond(struct drbd_conf *mdev, union drbd_state mask,
-            union drbd_state val)
-{
-       union drbd_state os, ns;
-       unsigned long flags;
-       enum drbd_state_rv rv;
-
-       if (test_and_clear_bit(CL_ST_CHG_SUCCESS, &mdev->flags))
-               return SS_CW_SUCCESS;
-
-       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);
-
-       if (!cl_wide_st_chg(mdev, os, ns))
-               rv = SS_CW_NO_NEED;
-       if (!rv) {
-               rv = is_valid_state(mdev, ns);
-               if (rv == SS_SUCCESS) {
-                       rv = is_valid_state_transition(mdev, ns, os);
-                       if (rv == SS_SUCCESS)
-                               rv = SS_UNKNOWN_ERROR; /* cont waiting, otherwise fail. */
-               }
-       }
-       spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
-
-       return rv;
-}
-
-/**
- * drbd_req_state() - Perform an eventually cluster wide state change
- * @mdev:      DRBD device.
- * @mask:      mask of state bits to change.
- * @val:       value of new state bits.
- * @f:         flags
- *
- * Should not be called directly, use drbd_request_state() or
- * _drbd_request_state().
- */
-static enum drbd_state_rv
-drbd_req_state(struct drbd_conf *mdev, union drbd_state mask,
-              union drbd_state val, enum chg_state_flags f)
-{
-       struct completion done;
-       unsigned long flags;
-       union drbd_state os, ns;
-       enum drbd_state_rv rv;
-
-       init_completion(&done);
-
-       if (f & CS_SERIALIZE)
-               mutex_lock(&mdev->state_mutex);
-
-       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);
-
-       if (cl_wide_st_chg(mdev, os, ns)) {
-               rv = is_valid_state(mdev, ns);
-               if (rv == SS_SUCCESS)
-                       rv = is_valid_state_transition(mdev, ns, os);
-               spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
-
-               if (rv < SS_SUCCESS) {
-                       if (f & CS_VERBOSE)
-                               print_st_err(mdev, os, ns, rv);
-                       goto abort;
-               }
-
-               drbd_state_lock(mdev);
-               if (!drbd_send_state_req(mdev, mask, val)) {
-                       drbd_state_unlock(mdev);
-                       rv = SS_CW_FAILED_BY_PEER;
-                       if (f & CS_VERBOSE)
-                               print_st_err(mdev, os, ns, rv);
-                       goto abort;
-               }
-
-               wait_event(mdev->state_wait,
-                       (rv = _req_st_cond(mdev, mask, val)));
-
-               if (rv < SS_SUCCESS) {
-                       drbd_state_unlock(mdev);
-                       if (f & CS_VERBOSE)
-                               print_st_err(mdev, os, ns, rv);
-                       goto abort;
-               }
-               spin_lock_irqsave(&mdev->tconn->req_lock, flags);
-               os = mdev->state;
-               ns.i = (os.i & ~mask.i) | val.i;
-               rv = _drbd_set_state(mdev, ns, f, &done);
-               drbd_state_unlock(mdev);
-       } else {
-               rv = _drbd_set_state(mdev, ns, f, &done);
-       }
-
-       spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
-
-       if (f & CS_WAIT_COMPLETE && rv == SS_SUCCESS) {
-               D_ASSERT(current != mdev->tconn->worker.task);
-               wait_for_completion(&done);
-       }
-
-abort:
-       if (f & CS_SERIALIZE)
-               mutex_unlock(&mdev->state_mutex);
-
-       return rv;
-}
-
-/**
- * _drbd_request_state() - Request a state change (with flags)
- * @mdev:      DRBD device.
- * @mask:      mask of state bits to change.
- * @val:       value of new state bits.
- * @f:         flags
- *
- * Cousin of drbd_request_state(), useful with the CS_WAIT_COMPLETE
- * flag, or when logging of failed state change requests is not desired.
- */
-enum drbd_state_rv
-_drbd_request_state(struct drbd_conf *mdev, union drbd_state mask,
-                   union drbd_state val, enum chg_state_flags f)
-{
-       enum drbd_state_rv rv;
-
-       wait_event(mdev->state_wait,
-                  (rv = drbd_req_state(mdev, mask, val, f)) != SS_IN_TRANSIENT_STATE);
-
-       return rv;
-}
-
-static void print_st(struct drbd_conf *mdev, char *name, union drbd_state ns)
-{
-       dev_err(DEV, " %s = { cs:%s ro:%s/%s ds:%s/%s %c%c%c%c }\n",
-           name,
-           drbd_conn_str(ns.conn),
-           drbd_role_str(ns.role),
-           drbd_role_str(ns.peer),
-           drbd_disk_str(ns.disk),
-           drbd_disk_str(ns.pdsk),
-           is_susp(ns) ? 's' : 'r',
-           ns.aftr_isp ? 'a' : '-',
-           ns.peer_isp ? 'p' : '-',
-           ns.user_isp ? 'u' : '-'
-           );
-}
-
-void print_st_err(struct drbd_conf *mdev, union drbd_state os,
-                 union drbd_state ns, enum drbd_state_rv err)
-{
-       if (err == SS_IN_TRANSIENT_STATE)
-               return;
-       dev_err(DEV, "State change failed: %s\n", drbd_set_st_err_str(err));
-       print_st(mdev, " state", os);
-       print_st(mdev, "wanted", ns);
-}
-
-
-/**
- * is_valid_state() - Returns an SS_ error code if ns is not valid
- * @mdev:      DRBD device.
- * @ns:                State to consider.
- */
-static enum drbd_state_rv
-is_valid_state(struct drbd_conf *mdev, union drbd_state ns)
-{
-       /* See drbd_state_sw_errors in drbd_strings.c */
-
-       enum drbd_fencing_p fp;
-       enum drbd_state_rv rv = SS_SUCCESS;
-
-       fp = FP_DONT_CARE;
-       if (get_ldev(mdev)) {
-               fp = mdev->ldev->dc.fencing;
-               put_ldev(mdev);
-       }
-
-       if (get_net_conf(mdev->tconn)) {
-               if (!mdev->tconn->net_conf->two_primaries &&
-                   ns.role == R_PRIMARY && ns.peer == R_PRIMARY)
-                       rv = SS_TWO_PRIMARIES;
-               put_net_conf(mdev->tconn);
-       }
-
-       if (rv <= 0)
-               /* already found a reason to abort */;
-       else if (ns.role == R_SECONDARY && mdev->open_cnt)
-               rv = SS_DEVICE_IN_USE;
-
-       else if (ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.disk < D_UP_TO_DATE)
-               rv = SS_NO_UP_TO_DATE_DISK;
-
-       else if (fp >= FP_RESOURCE &&
-                ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.pdsk >= D_UNKNOWN)
-               rv = SS_PRIMARY_NOP;
-
-       else if (ns.role == R_PRIMARY && ns.disk <= D_INCONSISTENT && ns.pdsk <= D_INCONSISTENT)
-               rv = SS_NO_UP_TO_DATE_DISK;
-
-       else if (ns.conn > C_CONNECTED && ns.disk < D_INCONSISTENT)
-               rv = SS_NO_LOCAL_DISK;
-
-       else if (ns.conn > C_CONNECTED && ns.pdsk < D_INCONSISTENT)
-               rv = SS_NO_REMOTE_DISK;
-
-       else if (ns.conn > C_CONNECTED && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE)
-               rv = SS_NO_UP_TO_DATE_DISK;
-
-       else if ((ns.conn == C_CONNECTED ||
-                 ns.conn == C_WF_BITMAP_S ||
-                 ns.conn == C_SYNC_SOURCE ||
-                 ns.conn == C_PAUSED_SYNC_S) &&
-                 ns.disk == D_OUTDATED)
-               rv = SS_CONNECTED_OUTDATES;
-
-       else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
-                (mdev->sync_conf.verify_alg[0] == 0))
-               rv = SS_NO_VERIFY_ALG;
-
-       else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
-                 mdev->tconn->agreed_pro_version < 88)
-               rv = SS_NOT_SUPPORTED;
-
-       else if (ns.conn >= C_CONNECTED && ns.pdsk == D_UNKNOWN)
-               rv = SS_CONNECTED_OUTDATES;
-
-       return rv;
-}
-
-/**
- * is_valid_state_transition() - Returns an SS_ error code if the state transition is not possible
- * @mdev:      DRBD device.
- * @ns:                new state.
- * @os:                old state.
- */
-static enum drbd_state_rv
-is_valid_state_transition(struct drbd_conf *mdev, union drbd_state ns,
-                         union drbd_state os)
-{
-       enum drbd_state_rv rv = SS_SUCCESS;
-
-       if ((ns.conn == C_STARTING_SYNC_T || ns.conn == C_STARTING_SYNC_S) &&
-           os.conn > C_CONNECTED)
-               rv = SS_RESYNC_RUNNING;
-
-       if (ns.conn == C_DISCONNECTING && os.conn == C_STANDALONE)
-               rv = SS_ALREADY_STANDALONE;
-
-       if (ns.disk > D_ATTACHING && os.disk == D_DISKLESS)
-               rv = SS_IS_DISKLESS;
-
-       if (ns.conn == C_WF_CONNECTION && os.conn < C_UNCONNECTED)
-               rv = SS_NO_NET_CONFIG;
-
-       if (ns.disk == D_OUTDATED && os.disk < D_OUTDATED && os.disk != D_ATTACHING)
-               rv = SS_LOWER_THAN_OUTDATED;
-
-       if (ns.conn == C_DISCONNECTING && os.conn == C_UNCONNECTED)
-               rv = SS_IN_TRANSIENT_STATE;
-
-       if (ns.conn == os.conn && ns.conn == C_WF_REPORT_PARAMS)
-               rv = SS_IN_TRANSIENT_STATE;
-
-       if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) && os.conn < C_CONNECTED)
-               rv = SS_NEED_CONNECTION;
-
-       if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
-           ns.conn != os.conn && os.conn > C_CONNECTED)
-               rv = SS_RESYNC_RUNNING;
-
-       if ((ns.conn == C_STARTING_SYNC_S || ns.conn == C_STARTING_SYNC_T) &&
-           os.conn < C_CONNECTED)
-               rv = SS_NEED_CONNECTION;
-
-       if ((ns.conn == C_SYNC_TARGET || ns.conn == C_SYNC_SOURCE)
-           && os.conn < C_WF_REPORT_PARAMS)
-               rv = SS_NEED_CONNECTION; /* No NetworkFailure -> SyncTarget etc... */
-
-       return rv;
-}
-
-/**
- * sanitize_state() - Resolves implicitly necessary additional changes to a state transition
- * @mdev:      DRBD device.
- * @os:                old state.
- * @ns:                new state.
- * @warn_sync_abort:
- *
- * When we loose connection, we have to set the state of the peers disk (pdsk)
- * to D_UNKNOWN. This rule and many more along those lines are in this function.
- */
-static union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state os,
-                                      union drbd_state ns, const char **warn_sync_abort)
-{
-       enum drbd_fencing_p fp;
-       enum drbd_disk_state disk_min, disk_max, pdsk_min, pdsk_max;
-
-       fp = FP_DONT_CARE;
-       if (get_ldev(mdev)) {
-               fp = mdev->ldev->dc.fencing;
-               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;
-
-       if (ns.conn < C_CONNECTED) {
-               ns.peer_isp = 0;
-               ns.peer = R_UNKNOWN;
-               if (ns.pdsk > D_UNKNOWN || ns.pdsk < D_INCONSISTENT)
-                       ns.pdsk = D_UNKNOWN;
-       }
-
-       /* Clear the aftr_isp when becoming unconfigured */
-       if (ns.conn == C_STANDALONE && ns.disk == D_DISKLESS && ns.role == R_SECONDARY)
-               ns.aftr_isp = 0;
-
-       /* Abort resync if a disk fails/detaches */
-       if (os.conn > C_CONNECTED && ns.conn > C_CONNECTED &&
-           (ns.disk <= D_FAILED || ns.pdsk <= D_FAILED)) {
-               if (warn_sync_abort)
-                       *warn_sync_abort =
-                               os.conn == C_VERIFY_S || os.conn == C_VERIFY_T ?
-                               "Online-verify" : "Resync";
-               ns.conn = C_CONNECTED;
-       }
-
-       /* Connection breaks down before we finished "Negotiating" */
-       if (ns.conn < C_CONNECTED && ns.disk == D_NEGOTIATING &&
-           get_ldev_if_state(mdev, D_NEGOTIATING)) {
-               if (mdev->ed_uuid == mdev->ldev->md.uuid[UI_CURRENT]) {
-                       ns.disk = mdev->new_state_tmp.disk;
-                       ns.pdsk = mdev->new_state_tmp.pdsk;
-               } else {
-                       dev_alert(DEV, "Connection lost while negotiating, no data!\n");
-                       ns.disk = D_DISKLESS;
-                       ns.pdsk = D_UNKNOWN;
-               }
-               put_ldev(mdev);
-       }
-
-       /* D_CONSISTENT and D_OUTDATED vanish when we get connected */
-       if (ns.conn >= C_CONNECTED && ns.conn < C_AHEAD) {
-               if (ns.disk == D_CONSISTENT || ns.disk == D_OUTDATED)
-                       ns.disk = D_UP_TO_DATE;
-               if (ns.pdsk == D_CONSISTENT || ns.pdsk == D_OUTDATED)
-                       ns.pdsk = D_UP_TO_DATE;
-       }
-
-       /* Implications of the connection stat on the disk states */
-       disk_min = D_DISKLESS;
-       disk_max = D_UP_TO_DATE;
-       pdsk_min = D_INCONSISTENT;
-       pdsk_max = D_UNKNOWN;
-       switch ((enum drbd_conns)ns.conn) {
-       case C_WF_BITMAP_T:
-       case C_PAUSED_SYNC_T:
-       case C_STARTING_SYNC_T:
-       case C_WF_SYNC_UUID:
-       case C_BEHIND:
-               disk_min = D_INCONSISTENT;
-               disk_max = D_OUTDATED;
-               pdsk_min = D_UP_TO_DATE;
-               pdsk_max = D_UP_TO_DATE;
-               break;
-       case C_VERIFY_S:
-       case C_VERIFY_T:
-               disk_min = D_UP_TO_DATE;
-               disk_max = D_UP_TO_DATE;
-               pdsk_min = D_UP_TO_DATE;
-               pdsk_max = D_UP_TO_DATE;
-               break;
-       case C_CONNECTED:
-               disk_min = D_DISKLESS;
-               disk_max = D_UP_TO_DATE;
-               pdsk_min = D_DISKLESS;
-               pdsk_max = D_UP_TO_DATE;
-               break;
-       case C_WF_BITMAP_S:
-       case C_PAUSED_SYNC_S:
-       case C_STARTING_SYNC_S:
-       case C_AHEAD:
-               disk_min = D_UP_TO_DATE;
-               disk_max = D_UP_TO_DATE;
-               pdsk_min = D_INCONSISTENT;
-               pdsk_max = D_CONSISTENT; /* D_OUTDATED would be nice. But explicit outdate necessary*/
-               break;
-       case C_SYNC_TARGET:
-               disk_min = D_INCONSISTENT;
-               disk_max = D_INCONSISTENT;
-               pdsk_min = D_UP_TO_DATE;
-               pdsk_max = D_UP_TO_DATE;
-               break;
-       case C_SYNC_SOURCE:
-               disk_min = D_UP_TO_DATE;
-               disk_max = D_UP_TO_DATE;
-               pdsk_min = D_INCONSISTENT;
-               pdsk_max = D_INCONSISTENT;
-               break;
-       case C_STANDALONE:
-       case C_DISCONNECTING:
-       case C_UNCONNECTED:
-       case C_TIMEOUT:
-       case C_BROKEN_PIPE:
-       case C_NETWORK_FAILURE:
-       case C_PROTOCOL_ERROR:
-       case C_TEAR_DOWN:
-       case C_WF_CONNECTION:
-       case C_WF_REPORT_PARAMS:
-       case C_MASK:
-               break;
-       }
-       if (ns.disk > disk_max)
-               ns.disk = disk_max;
-
-       if (ns.disk < disk_min) {
-               dev_warn(DEV, "Implicitly set disk from %s to %s\n",
-                        drbd_disk_str(ns.disk), drbd_disk_str(disk_min));
-               ns.disk = disk_min;
-       }
-       if (ns.pdsk > pdsk_max)
-               ns.pdsk = pdsk_max;
-
-       if (ns.pdsk < pdsk_min) {
-               dev_warn(DEV, "Implicitly set pdsk from %s to %s\n",
-                        drbd_disk_str(ns.pdsk), drbd_disk_str(pdsk_min));
-               ns.pdsk = pdsk_min;
-       }
-
-       if (fp == FP_STONITH &&
-           (ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.pdsk > D_OUTDATED) &&
-           !(os.role == R_PRIMARY && os.conn < C_CONNECTED && os.pdsk > D_OUTDATED))
-               ns.susp_fen = 1; /* Suspend IO while fence-peer handler runs (peer lost) */
-
-       if (mdev->sync_conf.on_no_data == OND_SUSPEND_IO &&
-           (ns.role == R_PRIMARY && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE) &&
-           !(os.role == R_PRIMARY && os.disk < D_UP_TO_DATE && os.pdsk < D_UP_TO_DATE))
-               ns.susp_nod = 1; /* Suspend IO while no data available (no accessible data available) */
-
-       if (ns.aftr_isp || ns.peer_isp || ns.user_isp) {
-               if (ns.conn == C_SYNC_SOURCE)
-                       ns.conn = C_PAUSED_SYNC_S;
-               if (ns.conn == C_SYNC_TARGET)
-                       ns.conn = C_PAUSED_SYNC_T;
-       } else {
-               if (ns.conn == C_PAUSED_SYNC_S)
-                       ns.conn = C_SYNC_SOURCE;
-               if (ns.conn == C_PAUSED_SYNC_T)
-                       ns.conn = C_SYNC_TARGET;
-       }
-
-       return ns;
-}
-
-/* helper for __drbd_set_state */
-static void set_ov_position(struct drbd_conf *mdev, enum drbd_conns cs)
-{
-       if (mdev->tconn->agreed_pro_version < 90)
-               mdev->ov_start_sector = 0;
-       mdev->rs_total = drbd_bm_bits(mdev);
-       mdev->ov_position = 0;
-       if (cs == C_VERIFY_T) {
-               /* starting online verify from an arbitrary position
-                * does not fit well into the existing protocol.
-                * on C_VERIFY_T, we initialize ov_left and friends
-                * implicitly in receive_DataRequest once the
-                * first P_OV_REQUEST is received */
-               mdev->ov_start_sector = ~(sector_t)0;
-       } else {
-               unsigned long bit = BM_SECT_TO_BIT(mdev->ov_start_sector);
-               if (bit >= mdev->rs_total) {
-                       mdev->ov_start_sector =
-                               BM_BIT_TO_SECT(mdev->rs_total - 1);
-                       mdev->rs_total = 1;
-               } else
-                       mdev->rs_total -= bit;
-               mdev->ov_position = mdev->ov_start_sector;
-       }
-       mdev->ov_left = mdev->rs_total;
-}
-
-static void drbd_resume_al(struct drbd_conf *mdev)
-{
-       if (test_and_clear_bit(AL_SUSPENDED, &mdev->flags))
-               dev_info(DEV, "Resumed AL updates\n");
-}
-
-/**
- * __drbd_set_state() - Set a new DRBD state
- * @mdev:      DRBD device.
- * @ns:                new state.
- * @flags:     Flags
- * @done:      Optional completion, that will get completed after the after_state_ch() finished
- *
- * Caller needs to hold req_lock, and global_state_lock. Do not call directly.
- */
-enum drbd_state_rv
-__drbd_set_state(struct drbd_conf *mdev, union drbd_state ns,
-                enum chg_state_flags flags, struct completion *done)
-{
-       union drbd_state os;
-       enum drbd_state_rv rv = SS_SUCCESS;
-       const char *warn_sync_abort = NULL;
-       struct after_state_chg_work *ascw;
-
-       os = mdev->state;
-
-       ns = sanitize_state(mdev, os, ns, &warn_sync_abort);
-
-       if (ns.i == os.i)
-               return SS_NOTHING_TO_DO;
-
-       if (!(flags & CS_HARD)) {
-               /*  pre-state-change checks ; only look at ns  */
-               /* See drbd_state_sw_errors in drbd_strings.c */
-
-               rv = is_valid_state(mdev, ns);
-               if (rv < SS_SUCCESS) {
-                       /* If the old state was illegal as well, then let
-                          this happen...*/
-
-                       if (is_valid_state(mdev, os) == rv)
-                               rv = is_valid_state_transition(mdev, ns, os);
-               } else
-                       rv = is_valid_state_transition(mdev, ns, os);
-       }
-
-       if (rv < SS_SUCCESS) {
-               if (flags & CS_VERBOSE)
-                       print_st_err(mdev, os, ns, rv);
-               return rv;
-       }
-
-       if (warn_sync_abort)
-               dev_warn(DEV, "%s aborted.\n", warn_sync_abort);
-
-       {
-       char *pbp, pb[300];
-       pbp = pb;
-       *pbp = 0;
-       if (ns.role != os.role)
-               pbp += sprintf(pbp, "role( %s -> %s ) ",
-                              drbd_role_str(os.role),
-                              drbd_role_str(ns.role));
-       if (ns.peer != os.peer)
-               pbp += sprintf(pbp, "peer( %s -> %s ) ",
-                              drbd_role_str(os.peer),
-                              drbd_role_str(ns.peer));
-       if (ns.conn != os.conn)
-               pbp += sprintf(pbp, "conn( %s -> %s ) ",
-                              drbd_conn_str(os.conn),
-                              drbd_conn_str(ns.conn));
-       if (ns.disk != os.disk)
-               pbp += sprintf(pbp, "disk( %s -> %s ) ",
-                              drbd_disk_str(os.disk),
-                              drbd_disk_str(ns.disk));
-       if (ns.pdsk != os.pdsk)
-               pbp += sprintf(pbp, "pdsk( %s -> %s ) ",
-                              drbd_disk_str(os.pdsk),
-                              drbd_disk_str(ns.pdsk));
-       if (is_susp(ns) != is_susp(os))
-               pbp += sprintf(pbp, "susp( %d -> %d ) ",
-                              is_susp(os),
-                              is_susp(ns));
-       if (ns.aftr_isp != os.aftr_isp)
-               pbp += sprintf(pbp, "aftr_isp( %d -> %d ) ",
-                              os.aftr_isp,
-                              ns.aftr_isp);
-       if (ns.peer_isp != os.peer_isp)
-               pbp += sprintf(pbp, "peer_isp( %d -> %d ) ",
-                              os.peer_isp,
-                              ns.peer_isp);
-       if (ns.user_isp != os.user_isp)
-               pbp += sprintf(pbp, "user_isp( %d -> %d ) ",
-                              os.user_isp,
-                              ns.user_isp);
-       dev_info(DEV, "%s\n", pb);
-       }
-
-       /* solve the race between becoming unconfigured,
-        * worker doing the cleanup, and
-        * admin reconfiguring us:
-        * on (re)configure, first set CONFIG_PENDING,
-        * then wait for a potentially exiting worker,
-        * start the worker, and schedule one no_op.
-        * then proceed with configuration.
-        */
-       if (ns.disk == D_DISKLESS &&
-           ns.conn == C_STANDALONE &&
-           ns.role == R_SECONDARY &&
-           !test_and_set_bit(CONFIG_PENDING, &mdev->flags))
-               set_bit(DEVICE_DYING, &mdev->flags);
-
-       /* if we are going -> D_FAILED or D_DISKLESS, grab one extra reference
-        * on the ldev here, to be sure the transition -> D_DISKLESS resp.
-        * drbd_ldev_destroy() won't happen before our corresponding
-        * after_state_ch works run, where we put_ldev again. */
-       if ((os.disk != D_FAILED && ns.disk == D_FAILED) ||
-           (os.disk != D_DISKLESS && ns.disk == D_DISKLESS))
-               atomic_inc(&mdev->local_cnt);
-
-       mdev->state = ns;
-
-       if (os.disk == D_ATTACHING && ns.disk >= D_NEGOTIATING)
-               drbd_print_uuids(mdev, "attached to UUIDs");
-
-       wake_up(&mdev->misc_wait);
-       wake_up(&mdev->state_wait);
-
-       /* aborted verify run. log the last position */
-       if ((os.conn == C_VERIFY_S || os.conn == C_VERIFY_T) &&
-           ns.conn < C_CONNECTED) {
-               mdev->ov_start_sector =
-                       BM_BIT_TO_SECT(drbd_bm_bits(mdev) - mdev->ov_left);
-               dev_info(DEV, "Online Verify reached sector %llu\n",
-                       (unsigned long long)mdev->ov_start_sector);
-       }
-
-       if ((os.conn == C_PAUSED_SYNC_T || os.conn == C_PAUSED_SYNC_S) &&
-           (ns.conn == C_SYNC_TARGET  || ns.conn == C_SYNC_SOURCE)) {
-               dev_info(DEV, "Syncer continues.\n");
-               mdev->rs_paused += (long)jiffies
-                                 -(long)mdev->rs_mark_time[mdev->rs_last_mark];
-               if (ns.conn == C_SYNC_TARGET)
-                       mod_timer(&mdev->resync_timer, jiffies);
-       }
-
-       if ((os.conn == C_SYNC_TARGET  || os.conn == C_SYNC_SOURCE) &&
-           (ns.conn == C_PAUSED_SYNC_T || ns.conn == C_PAUSED_SYNC_S)) {
-               dev_info(DEV, "Resync suspended\n");
-               mdev->rs_mark_time[mdev->rs_last_mark] = jiffies;
-       }
-
-       if (os.conn == C_CONNECTED &&
-           (ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T)) {
-               unsigned long now = jiffies;
-               int i;
-
-               set_ov_position(mdev, ns.conn);
-               mdev->rs_start = now;
-               mdev->rs_last_events = 0;
-               mdev->rs_last_sect_ev = 0;
-               mdev->ov_last_oos_size = 0;
-               mdev->ov_last_oos_start = 0;
-
-               for (i = 0; i < DRBD_SYNC_MARKS; i++) {
-                       mdev->rs_mark_left[i] = mdev->ov_left;
-                       mdev->rs_mark_time[i] = now;
-               }
-
-               drbd_rs_controller_reset(mdev);
-
-               if (ns.conn == C_VERIFY_S) {
-                       dev_info(DEV, "Starting Online Verify from sector %llu\n",
-                                       (unsigned long long)mdev->ov_position);
-                       mod_timer(&mdev->resync_timer, jiffies);
-               }
-       }
-
-       if (get_ldev(mdev)) {
-               u32 mdf = mdev->ldev->md.flags & ~(MDF_CONSISTENT|MDF_PRIMARY_IND|
-                                                MDF_CONNECTED_IND|MDF_WAS_UP_TO_DATE|
-                                                MDF_PEER_OUT_DATED|MDF_CRASHED_PRIMARY);
-
-               if (test_bit(CRASHED_PRIMARY, &mdev->flags))
-                       mdf |= MDF_CRASHED_PRIMARY;
-               if (mdev->state.role == R_PRIMARY ||
-                   (mdev->state.pdsk < D_INCONSISTENT && mdev->state.peer == R_PRIMARY))
-                       mdf |= MDF_PRIMARY_IND;
-               if (mdev->state.conn > C_WF_REPORT_PARAMS)
-                       mdf |= MDF_CONNECTED_IND;
-               if (mdev->state.disk > D_INCONSISTENT)
-                       mdf |= MDF_CONSISTENT;
-               if (mdev->state.disk > D_OUTDATED)
-                       mdf |= MDF_WAS_UP_TO_DATE;
-               if (mdev->state.pdsk <= D_OUTDATED && mdev->state.pdsk >= D_INCONSISTENT)
-                       mdf |= MDF_PEER_OUT_DATED;
-               if (mdf != mdev->ldev->md.flags) {
-                       mdev->ldev->md.flags = mdf;
-                       drbd_md_mark_dirty(mdev);
-               }
-               if (os.disk < D_CONSISTENT && ns.disk >= D_CONSISTENT)
-                       drbd_set_ed_uuid(mdev, mdev->ldev->md.uuid[UI_CURRENT]);
-               put_ldev(mdev);
-       }
-
-       /* Peer was forced D_UP_TO_DATE & R_PRIMARY, consider to resync */
-       if (os.disk == D_INCONSISTENT && os.pdsk == D_INCONSISTENT &&
-           os.peer == R_SECONDARY && ns.peer == R_PRIMARY)
-               set_bit(CONSIDER_RESYNC, &mdev->flags);
-
-       /* Receiver should clean up itself */
-       if (os.conn != C_DISCONNECTING && ns.conn == C_DISCONNECTING)
-               drbd_thread_stop_nowait(&mdev->tconn->receiver);
-
-       /* Now the receiver finished cleaning up itself, it should die */
-       if (os.conn != C_STANDALONE && ns.conn == C_STANDALONE)
-               drbd_thread_stop_nowait(&mdev->tconn->receiver);
-
-       /* Upon network failure, we need to restart the receiver. */
-       if (os.conn > C_TEAR_DOWN &&
-           ns.conn <= C_TEAR_DOWN && ns.conn >= C_TIMEOUT)
-               drbd_thread_restart_nowait(&mdev->tconn->receiver);
-
-       /* Resume AL writing if we get a connection */
-       if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED)
-               drbd_resume_al(mdev);
-
-       ascw = kmalloc(sizeof(*ascw), GFP_ATOMIC);
-       if (ascw) {
-               ascw->os = os;
-               ascw->ns = ns;
-               ascw->flags = flags;
-               ascw->w.cb = w_after_state_ch;
-               ascw->done = done;
-               drbd_queue_work(&mdev->tconn->data.work, &ascw->w);
-       } else {
-               dev_warn(DEV, "Could not kmalloc an ascw\n");
-       }
-
-       return rv;
-}
-
-static int w_after_state_ch(struct drbd_conf *mdev, struct drbd_work *w, int unused)
-{
-       struct after_state_chg_work *ascw =
-               container_of(w, struct after_state_chg_work, w);
-       after_state_ch(mdev, ascw->os, ascw->ns, ascw->flags);
-       if (ascw->flags & CS_WAIT_COMPLETE) {
-               D_ASSERT(ascw->done != NULL);
-               complete(ascw->done);
-       }
-       kfree(ascw);
-
-       return 1;
-}
-
-static void abw_start_sync(struct drbd_conf *mdev, int rv)
-{
-       if (rv) {
-               dev_err(DEV, "Writing the bitmap failed not starting resync.\n");
-               _drbd_request_state(mdev, NS(conn, C_CONNECTED), CS_VERBOSE);
-               return;
-       }
-
-       switch (mdev->state.conn) {
-       case C_STARTING_SYNC_T:
-               _drbd_request_state(mdev, NS(conn, C_WF_SYNC_UUID), CS_VERBOSE);
-               break;
-       case C_STARTING_SYNC_S:
-               drbd_start_resync(mdev, C_SYNC_SOURCE);
-               break;
-       }
-}
-
-int drbd_bitmap_io_from_worker(struct drbd_conf *mdev,
-               int (*io_fn)(struct drbd_conf *),
-               char *why, enum bm_flag flags)
-{
-       int rv;
-
-       D_ASSERT(current == mdev->tconn->worker.task);
-
-       /* open coded non-blocking drbd_suspend_io(mdev); */
-       set_bit(SUSPEND_IO, &mdev->flags);
-
-       drbd_bm_lock(mdev, why, flags);
-       rv = io_fn(mdev);
-       drbd_bm_unlock(mdev);
-
-       drbd_resume_io(mdev);
-
-       return rv;
-}
-
-/**
- * after_state_ch() - Perform after state change actions that may sleep
- * @mdev:      DRBD device.
- * @os:                old state.
- * @ns:                new state.
- * @flags:     Flags
- */
-static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
-                          union drbd_state ns, enum chg_state_flags flags)
-{
-       enum drbd_fencing_p fp;
-       enum drbd_req_event what = NOTHING;
-       union drbd_state nsm = (union drbd_state){ .i = -1 };
-
-       if (os.conn != C_CONNECTED && ns.conn == C_CONNECTED) {
-               clear_bit(CRASHED_PRIMARY, &mdev->flags);
-               if (mdev->p_uuid)
-                       mdev->p_uuid[UI_FLAGS] &= ~((u64)2);
-       }
-
-       fp = FP_DONT_CARE;
-       if (get_ldev(mdev)) {
-               fp = mdev->ldev->dc.fencing;
-               put_ldev(mdev);
-       }
-
-       /* Inform userspace about the change... */
-       drbd_bcast_state(mdev, ns);
-
-       if (!(os.role == R_PRIMARY && os.disk < D_UP_TO_DATE && os.pdsk < D_UP_TO_DATE) &&
-           (ns.role == R_PRIMARY && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE))
-               drbd_khelper(mdev, "pri-on-incon-degr");
-
-       /* Here we have the actions that are performed after a
-          state change. This function might sleep */
-
-       nsm.i = -1;
-       if (ns.susp_nod) {
-               if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED)
-                       what = RESEND;
-
-               if (os.disk == D_ATTACHING && ns.disk > D_ATTACHING)
-                       what = RESTART_FROZEN_DISK_IO;
-
-               if (what != NOTHING)
-                       nsm.susp_nod = 0;
-       }
-
-       if (ns.susp_fen) {
-               /* case1: The outdate peer handler is successful: */
-               if (os.pdsk > D_OUTDATED  && ns.pdsk <= D_OUTDATED) {
-                       tl_clear(mdev);
-                       if (test_bit(NEW_CUR_UUID, &mdev->flags)) {
-                               drbd_uuid_new_current(mdev);
-                               clear_bit(NEW_CUR_UUID, &mdev->flags);
-                       }
-                       spin_lock_irq(&mdev->tconn->req_lock);
-                       _drbd_set_state(_NS(mdev, susp_fen, 0), CS_VERBOSE, NULL);
-                       spin_unlock_irq(&mdev->tconn->req_lock);
-               }
-               /* case2: The connection was established again: */
-               if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED) {
-                       clear_bit(NEW_CUR_UUID, &mdev->flags);
-                       what = RESEND;
-                       nsm.susp_fen = 0;
-               }
-       }
-
-       if (what != NOTHING) {
-               spin_lock_irq(&mdev->tconn->req_lock);
-               _tl_restart(mdev, what);
-               nsm.i &= mdev->state.i;
-               _drbd_set_state(mdev, nsm, CS_VERBOSE, NULL);
-               spin_unlock_irq(&mdev->tconn->req_lock);
-       }
-
-       /* Became sync source.  With protocol >= 96, we still need to send out
-        * the sync uuid now. Need to do that before any drbd_send_state, or
-        * the other side may go "paused sync" before receiving the sync uuids,
-        * which is unexpected. */
-       if ((os.conn != C_SYNC_SOURCE && os.conn != C_PAUSED_SYNC_S) &&
-           (ns.conn == C_SYNC_SOURCE || ns.conn == C_PAUSED_SYNC_S) &&
-           mdev->tconn->agreed_pro_version >= 96 && get_ldev(mdev)) {
-               drbd_gen_and_send_sync_uuid(mdev);
-               put_ldev(mdev);
-       }
-
-       /* Do not change the order of the if above and the two below... */
-       if (os.pdsk == D_DISKLESS && ns.pdsk > D_DISKLESS) {      /* attach on the peer */
-               drbd_send_uuids(mdev);
-               drbd_send_state(mdev);
-       }
-       /* No point in queuing send_bitmap if we don't have a connection
-        * anymore, so check also the _current_ state, not only the new state
-        * at the time this work was queued. */
-       if (os.conn != C_WF_BITMAP_S && ns.conn == C_WF_BITMAP_S &&
-           mdev->state.conn == C_WF_BITMAP_S)
-               drbd_queue_bitmap_io(mdev, &drbd_send_bitmap, NULL,
-                               "send_bitmap (WFBitMapS)",
-                               BM_LOCKED_TEST_ALLOWED);
-
-       /* Lost contact to peer's copy of the data */
-       if ((os.pdsk >= D_INCONSISTENT &&
-            os.pdsk != D_UNKNOWN &&
-            os.pdsk != D_OUTDATED)
-       &&  (ns.pdsk < D_INCONSISTENT ||
-            ns.pdsk == D_UNKNOWN ||
-            ns.pdsk == D_OUTDATED)) {
-               if (get_ldev(mdev)) {
-                       if ((ns.role == R_PRIMARY || ns.peer == R_PRIMARY) &&
-                           mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE) {
-                               if (is_susp(mdev->state)) {
-                                       set_bit(NEW_CUR_UUID, &mdev->flags);
-                               } else {
-                                       drbd_uuid_new_current(mdev);
-                                       drbd_send_uuids(mdev);
-                               }
-                       }
-                       put_ldev(mdev);
-               }
-       }
-
-       if (ns.pdsk < D_INCONSISTENT && get_ldev(mdev)) {
-               if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0) {
-                       drbd_uuid_new_current(mdev);
-                       drbd_send_uuids(mdev);
-               }
-
-               /* D_DISKLESS Peer becomes secondary */
-               if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
-                       /* We may still be Primary ourselves.
-                        * No harm done if the bitmap still changes,
-                        * redirtied pages will follow later. */
-                       drbd_bitmap_io_from_worker(mdev, &drbd_bm_write,
-                               "demote diskless peer", BM_LOCKED_SET_ALLOWED);
-               put_ldev(mdev);
-       }
-
-       /* Write out all changed bits on demote.
-        * Though, no need to da that just yet
-        * if there is a resync going on still */
-       if (os.role == R_PRIMARY && ns.role == R_SECONDARY &&
-               mdev->state.conn <= C_CONNECTED && get_ldev(mdev)) {
-               /* No changes to the bitmap expected this time, so assert that,
-                * even though no harm was done if it did change. */
-               drbd_bitmap_io_from_worker(mdev, &drbd_bm_write,
-                               "demote", BM_LOCKED_TEST_ALLOWED);
-               put_ldev(mdev);
-       }
-
-       /* Last part of the attaching process ... */
-       if (ns.conn >= C_CONNECTED &&
-           os.disk == D_ATTACHING && ns.disk == D_NEGOTIATING) {
-               drbd_send_sizes(mdev, 0, 0);  /* to start sync... */
-               drbd_send_uuids(mdev);
-               drbd_send_state(mdev);
-       }
-
-       /* We want to pause/continue resync, tell peer. */
-       if (ns.conn >= C_CONNECTED &&
-            ((os.aftr_isp != ns.aftr_isp) ||
-             (os.user_isp != ns.user_isp)))
-               drbd_send_state(mdev);
-
-       /* In case one of the isp bits got set, suspend other devices. */
-       if ((!os.aftr_isp && !os.peer_isp && !os.user_isp) &&
-           (ns.aftr_isp || ns.peer_isp || ns.user_isp))
-               suspend_other_sg(mdev);
-
-       /* Make sure the peer gets informed about eventual state
-          changes (ISP bits) while we were in WFReportParams. */
-       if (os.conn == C_WF_REPORT_PARAMS && ns.conn >= C_CONNECTED)
-               drbd_send_state(mdev);
-
-       if (os.conn != C_AHEAD && ns.conn == C_AHEAD)
-               drbd_send_state(mdev);
-
-       /* We are in the progress to start a full sync... */
-       if ((os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
-           (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S))
-               /* no other bitmap changes expected during this phase */
-               drbd_queue_bitmap_io(mdev,
-                       &drbd_bmio_set_n_write, &abw_start_sync,
-                       "set_n_write from StartingSync", BM_LOCKED_TEST_ALLOWED);
-
-       /* We are invalidating our self... */
-       if (os.conn < C_CONNECTED && ns.conn < C_CONNECTED &&
-           os.disk > D_INCONSISTENT && ns.disk == D_INCONSISTENT)
-               /* other bitmap operation expected during this phase */
-               drbd_queue_bitmap_io(mdev, &drbd_bmio_set_n_write, NULL,
-                       "set_n_write from invalidate", BM_LOCKED_MASK);
-
-       /* first half of local IO error, failure to attach,
-        * or administrative detach */
-       if (os.disk != D_FAILED && ns.disk == D_FAILED) {
-               enum drbd_io_error_p eh;
-               int was_io_error;
-               /* corresponding get_ldev was in __drbd_set_state, to serialize
-                * our cleanup here with the transition to D_DISKLESS,
-                * so it is safe to dreference ldev here. */
-               eh = mdev->ldev->dc.on_io_error;
-               was_io_error = test_and_clear_bit(WAS_IO_ERROR, &mdev->flags);
-
-               /* current state still has to be D_FAILED,
-                * there is only one way out: to D_DISKLESS,
-                * and that may only happen after our put_ldev below. */
-               if (mdev->state.disk != D_FAILED)
-                       dev_err(DEV,
-                               "ASSERT FAILED: disk is %s during detach\n",
-                               drbd_disk_str(mdev->state.disk));
-
-               if (drbd_send_state(mdev))
-                       dev_warn(DEV, "Notified peer that I am detaching my disk\n");
-               else
-                       dev_err(DEV, "Sending state for detaching disk failed\n");
-
-               drbd_rs_cancel_all(mdev);
-
-               /* In case we want to get something to stable storage still,
-                * this may be the last chance.
-                * Following put_ldev may transition to D_DISKLESS. */
-               drbd_md_sync(mdev);
-               put_ldev(mdev);
-
-               if (was_io_error && eh == EP_CALL_HELPER)
-                       drbd_khelper(mdev, "local-io-error");
-       }
-
-        /* second half of local IO error, failure to attach,
-         * or administrative detach,
-         * after local_cnt references have reached zero again */
-        if (os.disk != D_DISKLESS && ns.disk == D_DISKLESS) {
-                /* We must still be diskless,
-                 * re-attach has to be serialized with this! */
-                if (mdev->state.disk != D_DISKLESS)
-                        dev_err(DEV,
-                                "ASSERT FAILED: disk is %s while going diskless\n",
-                                drbd_disk_str(mdev->state.disk));
-
-                mdev->rs_total = 0;
-                mdev->rs_failed = 0;
-                atomic_set(&mdev->rs_pending_cnt, 0);
-
-               if (drbd_send_state(mdev))
-                       dev_warn(DEV, "Notified peer that I'm now diskless.\n");
-               /* corresponding get_ldev in __drbd_set_state
-                * this may finally trigger drbd_ldev_destroy. */
-               put_ldev(mdev);
-       }
-
-       /* Notify peer that I had a local IO error, and did not detached.. */
-       if (os.disk == D_UP_TO_DATE && ns.disk == D_INCONSISTENT)
-               drbd_send_state(mdev);
-
-       /* Disks got bigger while they were detached */
-       if (ns.disk > D_NEGOTIATING && ns.pdsk > D_NEGOTIATING &&
-           test_and_clear_bit(RESYNC_AFTER_NEG, &mdev->flags)) {
-               if (ns.conn == C_CONNECTED)
-                       resync_after_online_grow(mdev);
-       }
-
-       /* A resync finished or aborted, wake paused devices... */
-       if ((os.conn > C_CONNECTED && ns.conn <= C_CONNECTED) ||
-           (os.peer_isp && !ns.peer_isp) ||
-           (os.user_isp && !ns.user_isp))
-               resume_next_sg(mdev);
-
-       /* sync target done with resync.  Explicitly notify peer, even though
-        * it should (at least for non-empty resyncs) already know itself. */
-       if (os.disk < D_UP_TO_DATE && os.conn >= C_SYNC_SOURCE && ns.conn == C_CONNECTED)
-               drbd_send_state(mdev);
-
-       /* This triggers bitmap writeout of potentially still unwritten pages
-        * if the resync finished cleanly, or aborted because of peer disk
-        * failure, or because of connection loss.
-        * For resync aborted because of local disk failure, we cannot do
-        * any bitmap writeout anymore.
-        * No harm done if some bits change during this phase.
-        */
-       if (os.conn > C_CONNECTED && ns.conn <= C_CONNECTED && get_ldev(mdev)) {
-               drbd_queue_bitmap_io(mdev, &drbd_bm_write, NULL,
-                       "write from resync_finished", BM_LOCKED_SET_ALLOWED);
-               put_ldev(mdev);
-       }
-
-       /* Upon network connection, we need to start the receiver */
-       if (os.conn == C_STANDALONE && ns.conn == C_UNCONNECTED)
-               drbd_thread_start(&mdev->tconn->receiver);
-
-       /* Terminate worker thread if we are unconfigured - it will be
-          restarted as needed... */
-       if (ns.disk == D_DISKLESS &&
-           ns.conn == C_STANDALONE &&
-           ns.role == R_SECONDARY) {
-               if (os.aftr_isp != ns.aftr_isp)
-                       resume_next_sg(mdev);
-               /* set in __drbd_set_state, unless CONFIG_PENDING was set */
-               if (test_bit(DEVICE_DYING, &mdev->flags))
-                       drbd_thread_stop_nowait(&mdev->tconn->worker);
-       }
-
-       drbd_md_sync(mdev);
-}
-
-
 static int drbd_thread_setup(void *arg)
 {
        struct drbd_thread *thi = (struct drbd_thread *) arg;
diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
new file mode 100644 (file)
index 0000000..38d330b
--- /dev/null
@@ -0,0 +1,1217 @@
+/*
+   drbd_state.c
+
+   This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
+
+   Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
+   Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
+   Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
+
+   Thanks to Carter Burden, Bart Grantham and Gennadiy Nerubayev
+   from Logicworks, Inc. for making SDP replication support possible.
+
+   drbd is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   drbd is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with drbd; see the file COPYING.  If not, write to
+   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/drbd_limits.h>
+#include "drbd_int.h"
+#include "drbd_req.h"
+
+struct after_state_chg_work {
+       struct drbd_work w;
+       union drbd_state os;
+       union drbd_state ns;
+       enum chg_state_flags flags;
+       struct completion *done;
+};
+
+
+extern void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what);
+int drbd_send_state_req(struct drbd_conf *, union drbd_state, union drbd_state);
+static int w_after_state_ch(struct drbd_conf *mdev, struct drbd_work *w, int unused);
+static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
+                          union drbd_state ns, enum chg_state_flags flags);
+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 union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state os,
+                                      union drbd_state ns, const char **warn_sync_abort);
+
+/**
+ * cl_wide_st_chg() - true if the state change is a cluster wide one
+ * @mdev:      DRBD device.
+ * @os:                old (current) state.
+ * @ns:                new (wanted) state.
+ */
+static int cl_wide_st_chg(struct drbd_conf *mdev,
+                         union drbd_state os, union drbd_state ns)
+{
+       return (os.conn >= C_CONNECTED && ns.conn >= C_CONNECTED &&
+                ((os.role != R_PRIMARY && ns.role == R_PRIMARY) ||
+                 (os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
+                 (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S) ||
+                 (os.disk != D_DISKLESS && ns.disk == D_DISKLESS))) ||
+               (os.conn >= C_CONNECTED && ns.conn == C_DISCONNECTING) ||
+               (os.conn == C_CONNECTED && ns.conn == C_VERIFY_S);
+}
+
+enum drbd_state_rv
+drbd_change_state(struct drbd_conf *mdev, enum chg_state_flags f,
+                 union drbd_state mask, union drbd_state val)
+{
+       unsigned long flags;
+       union drbd_state os, ns;
+       enum drbd_state_rv rv;
+
+       spin_lock_irqsave(&mdev->tconn->req_lock, flags);
+       os = mdev->state;
+       ns.i = (os.i & ~mask.i) | val.i;
+       rv = _drbd_set_state(mdev, ns, f, NULL);
+       ns = mdev->state;
+       spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
+
+       return rv;
+}
+
+/**
+ * drbd_force_state() - Impose a change which happens outside our control on our state
+ * @mdev:      DRBD device.
+ * @mask:      mask of state bits to change.
+ * @val:       value of new state bits.
+ */
+void drbd_force_state(struct drbd_conf *mdev,
+       union drbd_state mask, union drbd_state val)
+{
+       drbd_change_state(mdev, CS_HARD, mask, val);
+}
+
+static enum drbd_state_rv
+_req_st_cond(struct drbd_conf *mdev, union drbd_state mask,
+            union drbd_state val)
+{
+       union drbd_state os, ns;
+       unsigned long flags;
+       enum drbd_state_rv rv;
+
+       if (test_and_clear_bit(CL_ST_CHG_SUCCESS, &mdev->flags))
+               return SS_CW_SUCCESS;
+
+       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);
+
+       if (!cl_wide_st_chg(mdev, os, ns))
+               rv = SS_CW_NO_NEED;
+       if (!rv) {
+               rv = is_valid_state(mdev, ns);
+               if (rv == SS_SUCCESS) {
+                       rv = is_valid_soft_transition(os, ns);
+                       if (rv == SS_SUCCESS)
+                               rv = SS_UNKNOWN_ERROR; /* cont waiting, otherwise fail. */
+               }
+       }
+       spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
+
+       return rv;
+}
+
+/**
+ * drbd_req_state() - Perform an eventually cluster wide state change
+ * @mdev:      DRBD device.
+ * @mask:      mask of state bits to change.
+ * @val:       value of new state bits.
+ * @f:         flags
+ *
+ * Should not be called directly, use drbd_request_state() or
+ * _drbd_request_state().
+ */
+static enum drbd_state_rv
+drbd_req_state(struct drbd_conf *mdev, union drbd_state mask,
+              union drbd_state val, enum chg_state_flags f)
+{
+       struct completion done;
+       unsigned long flags;
+       union drbd_state os, ns;
+       enum drbd_state_rv rv;
+
+       init_completion(&done);
+
+       if (f & CS_SERIALIZE)
+               mutex_lock(&mdev->state_mutex);
+
+       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);
+
+       if (cl_wide_st_chg(mdev, os, ns)) {
+               rv = is_valid_state(mdev, ns);
+               if (rv == SS_SUCCESS)
+                       rv = is_valid_soft_transition(os, ns);
+               spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
+
+               if (rv < SS_SUCCESS) {
+                       if (f & CS_VERBOSE)
+                               print_st_err(mdev, os, ns, rv);
+                       goto abort;
+               }
+
+               drbd_state_lock(mdev);
+               if (!drbd_send_state_req(mdev, mask, val)) {
+                       drbd_state_unlock(mdev);
+                       rv = SS_CW_FAILED_BY_PEER;
+                       if (f & CS_VERBOSE)
+                               print_st_err(mdev, os, ns, rv);
+                       goto abort;
+               }
+
+               wait_event(mdev->state_wait,
+                       (rv = _req_st_cond(mdev, mask, val)));
+
+               if (rv < SS_SUCCESS) {
+                       drbd_state_unlock(mdev);
+                       if (f & CS_VERBOSE)
+                               print_st_err(mdev, os, ns, rv);
+                       goto abort;
+               }
+               spin_lock_irqsave(&mdev->tconn->req_lock, flags);
+               os = mdev->state;
+               ns.i = (os.i & ~mask.i) | val.i;
+               rv = _drbd_set_state(mdev, ns, f, &done);
+               drbd_state_unlock(mdev);
+       } else {
+               rv = _drbd_set_state(mdev, ns, f, &done);
+       }
+
+       spin_unlock_irqrestore(&mdev->tconn->req_lock, flags);
+
+       if (f & CS_WAIT_COMPLETE && rv == SS_SUCCESS) {
+               D_ASSERT(current != mdev->tconn->worker.task);
+               wait_for_completion(&done);
+       }
+
+abort:
+       if (f & CS_SERIALIZE)
+               mutex_unlock(&mdev->state_mutex);
+
+       return rv;
+}
+
+/**
+ * _drbd_request_state() - Request a state change (with flags)
+ * @mdev:      DRBD device.
+ * @mask:      mask of state bits to change.
+ * @val:       value of new state bits.
+ * @f:         flags
+ *
+ * Cousin of drbd_request_state(), useful with the CS_WAIT_COMPLETE
+ * flag, or when logging of failed state change requests is not desired.
+ */
+enum drbd_state_rv
+_drbd_request_state(struct drbd_conf *mdev, union drbd_state mask,
+                   union drbd_state val, enum chg_state_flags f)
+{
+       enum drbd_state_rv rv;
+
+       wait_event(mdev->state_wait,
+                  (rv = drbd_req_state(mdev, mask, val, f)) != SS_IN_TRANSIENT_STATE);
+
+       return rv;
+}
+
+static void print_st(struct drbd_conf *mdev, char *name, union drbd_state ns)
+{
+       dev_err(DEV, " %s = { cs:%s ro:%s/%s ds:%s/%s %c%c%c%c%c%c }\n",
+           name,
+           drbd_conn_str(ns.conn),
+           drbd_role_str(ns.role),
+           drbd_role_str(ns.peer),
+           drbd_disk_str(ns.disk),
+           drbd_disk_str(ns.pdsk),
+           is_susp(ns) ? 's' : 'r',
+           ns.aftr_isp ? 'a' : '-',
+           ns.peer_isp ? 'p' : '-',
+           ns.user_isp ? 'u' : '-',
+           ns.susp_fen ? 'F' : '-',
+           ns.susp_nod ? 'N' : '-'
+           );
+}
+
+void print_st_err(struct drbd_conf *mdev, union drbd_state os,
+                 union drbd_state ns, enum drbd_state_rv err)
+{
+       if (err == SS_IN_TRANSIENT_STATE)
+               return;
+       dev_err(DEV, "State change failed: %s\n", drbd_set_st_err_str(err));
+       print_st(mdev, " state", os);
+       print_st(mdev, "wanted", ns);
+}
+
+
+/**
+ * is_valid_state() - Returns an SS_ error code if ns is not valid
+ * @mdev:      DRBD device.
+ * @ns:                State to consider.
+ */
+static enum drbd_state_rv
+is_valid_state(struct drbd_conf *mdev, union drbd_state ns)
+{
+       /* See drbd_state_sw_errors in drbd_strings.c */
+
+       enum drbd_fencing_p fp;
+       enum drbd_state_rv rv = SS_SUCCESS;
+
+       fp = FP_DONT_CARE;
+       if (get_ldev(mdev)) {
+               fp = mdev->ldev->dc.fencing;
+               put_ldev(mdev);
+       }
+
+       if (get_net_conf(mdev->tconn)) {
+               if (!mdev->tconn->net_conf->two_primaries &&
+                   ns.role == R_PRIMARY && ns.peer == R_PRIMARY)
+                       rv = SS_TWO_PRIMARIES;
+               put_net_conf(mdev->tconn);
+       }
+
+       if (rv <= 0)
+               /* already found a reason to abort */;
+       else if (ns.role == R_SECONDARY && mdev->open_cnt)
+               rv = SS_DEVICE_IN_USE;
+
+       else if (ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.disk < D_UP_TO_DATE)
+               rv = SS_NO_UP_TO_DATE_DISK;
+
+       else if (fp >= FP_RESOURCE &&
+                ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.pdsk >= D_UNKNOWN)
+               rv = SS_PRIMARY_NOP;
+
+       else if (ns.role == R_PRIMARY && ns.disk <= D_INCONSISTENT && ns.pdsk <= D_INCONSISTENT)
+               rv = SS_NO_UP_TO_DATE_DISK;
+
+       else if (ns.conn > C_CONNECTED && ns.disk < D_INCONSISTENT)
+               rv = SS_NO_LOCAL_DISK;
+
+       else if (ns.conn > C_CONNECTED && ns.pdsk < D_INCONSISTENT)
+               rv = SS_NO_REMOTE_DISK;
+
+       else if (ns.conn > C_CONNECTED && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE)
+               rv = SS_NO_UP_TO_DATE_DISK;
+
+       else if ((ns.conn == C_CONNECTED ||
+                 ns.conn == C_WF_BITMAP_S ||
+                 ns.conn == C_SYNC_SOURCE ||
+                 ns.conn == C_PAUSED_SYNC_S) &&
+                 ns.disk == D_OUTDATED)
+               rv = SS_CONNECTED_OUTDATES;
+
+       else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
+                (mdev->sync_conf.verify_alg[0] == 0))
+               rv = SS_NO_VERIFY_ALG;
+
+       else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
+                 mdev->tconn->agreed_pro_version < 88)
+               rv = SS_NOT_SUPPORTED;
+
+       else if (ns.conn >= C_CONNECTED && ns.pdsk == D_UNKNOWN)
+               rv = SS_CONNECTED_OUTDATES;
+
+       return rv;
+}
+
+/**
+ * is_valid_soft_transition() - Returns an SS_ error code if the state transition is not possible
+ * @mdev:      DRBD device.
+ * @ns:                new state.
+ * @os:                old state.
+ */
+static enum drbd_state_rv
+is_valid_soft_transition(union drbd_state os, union drbd_state ns)
+{
+       enum drbd_state_rv rv = SS_SUCCESS;
+
+       if ((ns.conn == C_STARTING_SYNC_T || ns.conn == C_STARTING_SYNC_S) &&
+           os.conn > C_CONNECTED)
+               rv = SS_RESYNC_RUNNING;
+
+       if (ns.conn == C_DISCONNECTING && os.conn == C_STANDALONE)
+               rv = SS_ALREADY_STANDALONE;
+
+       if (ns.disk > D_ATTACHING && os.disk == D_DISKLESS)
+               rv = SS_IS_DISKLESS;
+
+       if (ns.conn == C_WF_CONNECTION && os.conn < C_UNCONNECTED)
+               rv = SS_NO_NET_CONFIG;
+
+       if (ns.disk == D_OUTDATED && os.disk < D_OUTDATED && os.disk != D_ATTACHING)
+               rv = SS_LOWER_THAN_OUTDATED;
+
+       if (ns.conn == C_DISCONNECTING && os.conn == C_UNCONNECTED)
+               rv = SS_IN_TRANSIENT_STATE;
+
+       if (ns.conn == os.conn && ns.conn == C_WF_REPORT_PARAMS)
+               rv = SS_IN_TRANSIENT_STATE;
+
+       if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) && os.conn < C_CONNECTED)
+               rv = SS_NEED_CONNECTION;
+
+       if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
+           ns.conn != os.conn && os.conn > C_CONNECTED)
+               rv = SS_RESYNC_RUNNING;
+
+       if ((ns.conn == C_STARTING_SYNC_S || ns.conn == C_STARTING_SYNC_T) &&
+           os.conn < C_CONNECTED)
+               rv = SS_NEED_CONNECTION;
+
+       if ((ns.conn == C_SYNC_TARGET || ns.conn == C_SYNC_SOURCE)
+           && os.conn < C_WF_REPORT_PARAMS)
+               rv = SS_NEED_CONNECTION; /* No NetworkFailure -> SyncTarget etc... */
+
+       return rv;
+}
+
+/**
+ * sanitize_state() - Resolves implicitly necessary additional changes to a state transition
+ * @mdev:      DRBD device.
+ * @os:                old state.
+ * @ns:                new state.
+ * @warn_sync_abort:
+ *
+ * When we loose connection, we have to set the state of the peers disk (pdsk)
+ * to D_UNKNOWN. This rule and many more along those lines are in this function.
+ */
+static union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state os,
+                                      union drbd_state ns, const char **warn_sync_abort)
+{
+       enum drbd_fencing_p fp;
+       enum drbd_disk_state disk_min, disk_max, pdsk_min, pdsk_max;
+
+       fp = FP_DONT_CARE;
+       if (get_ldev(mdev)) {
+               fp = mdev->ldev->dc.fencing;
+               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;
+
+       if (ns.conn < C_CONNECTED) {
+               ns.peer_isp = 0;
+               ns.peer = R_UNKNOWN;
+               if (ns.pdsk > D_UNKNOWN || ns.pdsk < D_INCONSISTENT)
+                       ns.pdsk = D_UNKNOWN;
+       }
+
+       /* Clear the aftr_isp when becoming unconfigured */
+       if (ns.conn == C_STANDALONE && ns.disk == D_DISKLESS && ns.role == R_SECONDARY)
+               ns.aftr_isp = 0;
+
+       /* Abort resync if a disk fails/detaches */
+       if (os.conn > C_CONNECTED && ns.conn > C_CONNECTED &&
+           (ns.disk <= D_FAILED || ns.pdsk <= D_FAILED)) {
+               if (warn_sync_abort)
+                       *warn_sync_abort =
+                               os.conn == C_VERIFY_S || os.conn == C_VERIFY_T ?
+                               "Online-verify" : "Resync";
+               ns.conn = C_CONNECTED;
+       }
+
+       /* Connection breaks down before we finished "Negotiating" */
+       if (ns.conn < C_CONNECTED && ns.disk == D_NEGOTIATING &&
+           get_ldev_if_state(mdev, D_NEGOTIATING)) {
+               if (mdev->ed_uuid == mdev->ldev->md.uuid[UI_CURRENT]) {
+                       ns.disk = mdev->new_state_tmp.disk;
+                       ns.pdsk = mdev->new_state_tmp.pdsk;
+               } else {
+                       dev_alert(DEV, "Connection lost while negotiating, no data!\n");
+                       ns.disk = D_DISKLESS;
+                       ns.pdsk = D_UNKNOWN;
+               }
+               put_ldev(mdev);
+       }
+
+       /* D_CONSISTENT and D_OUTDATED vanish when we get connected */
+       if (ns.conn >= C_CONNECTED && ns.conn < C_AHEAD) {
+               if (ns.disk == D_CONSISTENT || ns.disk == D_OUTDATED)
+                       ns.disk = D_UP_TO_DATE;
+               if (ns.pdsk == D_CONSISTENT || ns.pdsk == D_OUTDATED)
+                       ns.pdsk = D_UP_TO_DATE;
+       }
+
+       /* Implications of the connection stat on the disk states */
+       disk_min = D_DISKLESS;
+       disk_max = D_UP_TO_DATE;
+       pdsk_min = D_INCONSISTENT;
+       pdsk_max = D_UNKNOWN;
+       switch ((enum drbd_conns)ns.conn) {
+       case C_WF_BITMAP_T:
+       case C_PAUSED_SYNC_T:
+       case C_STARTING_SYNC_T:
+       case C_WF_SYNC_UUID:
+       case C_BEHIND:
+               disk_min = D_INCONSISTENT;
+               disk_max = D_OUTDATED;
+               pdsk_min = D_UP_TO_DATE;
+               pdsk_max = D_UP_TO_DATE;
+               break;
+       case C_VERIFY_S:
+       case C_VERIFY_T:
+               disk_min = D_UP_TO_DATE;
+               disk_max = D_UP_TO_DATE;
+               pdsk_min = D_UP_TO_DATE;
+               pdsk_max = D_UP_TO_DATE;
+               break;
+       case C_CONNECTED:
+               disk_min = D_DISKLESS;
+               disk_max = D_UP_TO_DATE;
+               pdsk_min = D_DISKLESS;
+               pdsk_max = D_UP_TO_DATE;
+               break;
+       case C_WF_BITMAP_S:
+       case C_PAUSED_SYNC_S:
+       case C_STARTING_SYNC_S:
+       case C_AHEAD:
+               disk_min = D_UP_TO_DATE;
+               disk_max = D_UP_TO_DATE;
+               pdsk_min = D_INCONSISTENT;
+               pdsk_max = D_CONSISTENT; /* D_OUTDATED would be nice. But explicit outdate necessary*/
+               break;
+       case C_SYNC_TARGET:
+               disk_min = D_INCONSISTENT;
+               disk_max = D_INCONSISTENT;
+               pdsk_min = D_UP_TO_DATE;
+               pdsk_max = D_UP_TO_DATE;
+               break;
+       case C_SYNC_SOURCE:
+               disk_min = D_UP_TO_DATE;
+               disk_max = D_UP_TO_DATE;
+               pdsk_min = D_INCONSISTENT;
+               pdsk_max = D_INCONSISTENT;
+               break;
+       case C_STANDALONE:
+       case C_DISCONNECTING:
+       case C_UNCONNECTED:
+       case C_TIMEOUT:
+       case C_BROKEN_PIPE:
+       case C_NETWORK_FAILURE:
+       case C_PROTOCOL_ERROR:
+       case C_TEAR_DOWN:
+       case C_WF_CONNECTION:
+       case C_WF_REPORT_PARAMS:
+       case C_MASK:
+               break;
+       }
+       if (ns.disk > disk_max)
+               ns.disk = disk_max;
+
+       if (ns.disk < disk_min) {
+               dev_warn(DEV, "Implicitly set disk from %s to %s\n",
+                        drbd_disk_str(ns.disk), drbd_disk_str(disk_min));
+               ns.disk = disk_min;
+       }
+       if (ns.pdsk > pdsk_max)
+               ns.pdsk = pdsk_max;
+
+       if (ns.pdsk < pdsk_min) {
+               dev_warn(DEV, "Implicitly set pdsk from %s to %s\n",
+                        drbd_disk_str(ns.pdsk), drbd_disk_str(pdsk_min));
+               ns.pdsk = pdsk_min;
+       }
+
+       if (fp == FP_STONITH &&
+           (ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.pdsk > D_OUTDATED) &&
+           !(os.role == R_PRIMARY && os.conn < C_CONNECTED && os.pdsk > D_OUTDATED))
+               ns.susp_fen = 1; /* Suspend IO while fence-peer handler runs (peer lost) */
+
+       if (mdev->sync_conf.on_no_data == OND_SUSPEND_IO &&
+           (ns.role == R_PRIMARY && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE) &&
+           !(os.role == R_PRIMARY && os.disk < D_UP_TO_DATE && os.pdsk < D_UP_TO_DATE))
+               ns.susp_nod = 1; /* Suspend IO while no data available (no accessible data available) */
+
+       if (ns.aftr_isp || ns.peer_isp || ns.user_isp) {
+               if (ns.conn == C_SYNC_SOURCE)
+                       ns.conn = C_PAUSED_SYNC_S;
+               if (ns.conn == C_SYNC_TARGET)
+                       ns.conn = C_PAUSED_SYNC_T;
+       } else {
+               if (ns.conn == C_PAUSED_SYNC_S)
+                       ns.conn = C_SYNC_SOURCE;
+               if (ns.conn == C_PAUSED_SYNC_T)
+                       ns.conn = C_SYNC_TARGET;
+       }
+
+       return ns;
+}
+
+void drbd_resume_al(struct drbd_conf *mdev)
+{
+       if (test_and_clear_bit(AL_SUSPENDED, &mdev->flags))
+               dev_info(DEV, "Resumed AL updates\n");
+}
+
+/* helper for __drbd_set_state */
+static void set_ov_position(struct drbd_conf *mdev, enum drbd_conns cs)
+{
+       if (mdev->tconn->agreed_pro_version < 90)
+               mdev->ov_start_sector = 0;
+       mdev->rs_total = drbd_bm_bits(mdev);
+       mdev->ov_position = 0;
+       if (cs == C_VERIFY_T) {
+               /* starting online verify from an arbitrary position
+                * does not fit well into the existing protocol.
+                * on C_VERIFY_T, we initialize ov_left and friends
+                * implicitly in receive_DataRequest once the
+                * first P_OV_REQUEST is received */
+               mdev->ov_start_sector = ~(sector_t)0;
+       } else {
+               unsigned long bit = BM_SECT_TO_BIT(mdev->ov_start_sector);
+               if (bit >= mdev->rs_total) {
+                       mdev->ov_start_sector =
+                               BM_BIT_TO_SECT(mdev->rs_total - 1);
+                       mdev->rs_total = 1;
+               } else
+                       mdev->rs_total -= bit;
+               mdev->ov_position = mdev->ov_start_sector;
+       }
+       mdev->ov_left = mdev->rs_total;
+}
+
+/**
+ * __drbd_set_state() - Set a new DRBD state
+ * @mdev:      DRBD device.
+ * @ns:                new state.
+ * @flags:     Flags
+ * @done:      Optional completion, that will get completed after the after_state_ch() finished
+ *
+ * Caller needs to hold req_lock, and global_state_lock. Do not call directly.
+ */
+enum drbd_state_rv
+__drbd_set_state(struct drbd_conf *mdev, union drbd_state ns,
+                enum chg_state_flags flags, struct completion *done)
+{
+       union drbd_state os;
+       enum drbd_state_rv rv = SS_SUCCESS;
+       const char *warn_sync_abort = NULL;
+       struct after_state_chg_work *ascw;
+
+       os = mdev->state;
+
+       ns = sanitize_state(mdev, os, ns, &warn_sync_abort);
+
+       if (ns.i == os.i)
+               return SS_NOTHING_TO_DO;
+
+       if (!(flags & CS_HARD)) {
+               /*  pre-state-change checks ; only look at ns  */
+               /* See drbd_state_sw_errors in drbd_strings.c */
+
+               rv = is_valid_state(mdev, ns);
+               if (rv < SS_SUCCESS) {
+                       /* If the old state was illegal as well, then let
+                          this happen...*/
+
+                       if (is_valid_state(mdev, os) == rv)
+                               rv = is_valid_soft_transition(os, ns);
+               } else
+                       rv = is_valid_soft_transition(os, ns);
+       }
+
+       if (rv < SS_SUCCESS) {
+               if (flags & CS_VERBOSE)
+                       print_st_err(mdev, os, ns, rv);
+               return rv;
+       }
+
+       if (warn_sync_abort)
+               dev_warn(DEV, "%s aborted.\n", warn_sync_abort);
+
+       {
+       char *pbp, pb[300];
+       pbp = pb;
+       *pbp = 0;
+       if (ns.role != os.role)
+               pbp += sprintf(pbp, "role( %s -> %s ) ",
+                              drbd_role_str(os.role),
+                              drbd_role_str(ns.role));
+       if (ns.peer != os.peer)
+               pbp += sprintf(pbp, "peer( %s -> %s ) ",
+                              drbd_role_str(os.peer),
+                              drbd_role_str(ns.peer));
+       if (ns.conn != os.conn)
+               pbp += sprintf(pbp, "conn( %s -> %s ) ",
+                              drbd_conn_str(os.conn),
+                              drbd_conn_str(ns.conn));
+       if (ns.disk != os.disk)
+               pbp += sprintf(pbp, "disk( %s -> %s ) ",
+                              drbd_disk_str(os.disk),
+                              drbd_disk_str(ns.disk));
+       if (ns.pdsk != os.pdsk)
+               pbp += sprintf(pbp, "pdsk( %s -> %s ) ",
+                              drbd_disk_str(os.pdsk),
+                              drbd_disk_str(ns.pdsk));
+       if (is_susp(ns) != is_susp(os))
+               pbp += sprintf(pbp, "susp( %d -> %d ) ",
+                              is_susp(os),
+                              is_susp(ns));
+       if (ns.aftr_isp != os.aftr_isp)
+               pbp += sprintf(pbp, "aftr_isp( %d -> %d ) ",
+                              os.aftr_isp,
+                              ns.aftr_isp);
+       if (ns.peer_isp != os.peer_isp)
+               pbp += sprintf(pbp, "peer_isp( %d -> %d ) ",
+                              os.peer_isp,
+                              ns.peer_isp);
+       if (ns.user_isp != os.user_isp)
+               pbp += sprintf(pbp, "user_isp( %d -> %d ) ",
+                              os.user_isp,
+                              ns.user_isp);
+       dev_info(DEV, "%s\n", pb);
+       }
+
+       /* solve the race between becoming unconfigured,
+        * worker doing the cleanup, and
+        * admin reconfiguring us:
+        * on (re)configure, first set CONFIG_PENDING,
+        * then wait for a potentially exiting worker,
+        * start the worker, and schedule one no_op.
+        * then proceed with configuration.
+        */
+       if (ns.disk == D_DISKLESS &&
+           ns.conn == C_STANDALONE &&
+           ns.role == R_SECONDARY &&
+           !test_and_set_bit(CONFIG_PENDING, &mdev->flags))
+               set_bit(DEVICE_DYING, &mdev->flags);
+
+       /* if we are going -> D_FAILED or D_DISKLESS, grab one extra reference
+        * on the ldev here, to be sure the transition -> D_DISKLESS resp.
+        * drbd_ldev_destroy() won't happen before our corresponding
+        * after_state_ch works run, where we put_ldev again. */
+       if ((os.disk != D_FAILED && ns.disk == D_FAILED) ||
+           (os.disk != D_DISKLESS && ns.disk == D_DISKLESS))
+               atomic_inc(&mdev->local_cnt);
+
+       mdev->state = ns;
+
+       if (os.disk == D_ATTACHING && ns.disk >= D_NEGOTIATING)
+               drbd_print_uuids(mdev, "attached to UUIDs");
+
+       wake_up(&mdev->misc_wait);
+       wake_up(&mdev->state_wait);
+
+       /* aborted verify run. log the last position */
+       if ((os.conn == C_VERIFY_S || os.conn == C_VERIFY_T) &&
+           ns.conn < C_CONNECTED) {
+               mdev->ov_start_sector =
+                       BM_BIT_TO_SECT(drbd_bm_bits(mdev) - mdev->ov_left);
+               dev_info(DEV, "Online Verify reached sector %llu\n",
+                       (unsigned long long)mdev->ov_start_sector);
+       }
+
+       if ((os.conn == C_PAUSED_SYNC_T || os.conn == C_PAUSED_SYNC_S) &&
+           (ns.conn == C_SYNC_TARGET  || ns.conn == C_SYNC_SOURCE)) {
+               dev_info(DEV, "Syncer continues.\n");
+               mdev->rs_paused += (long)jiffies
+                                 -(long)mdev->rs_mark_time[mdev->rs_last_mark];
+               if (ns.conn == C_SYNC_TARGET)
+                       mod_timer(&mdev->resync_timer, jiffies);
+       }
+
+       if ((os.conn == C_SYNC_TARGET  || os.conn == C_SYNC_SOURCE) &&
+           (ns.conn == C_PAUSED_SYNC_T || ns.conn == C_PAUSED_SYNC_S)) {
+               dev_info(DEV, "Resync suspended\n");
+               mdev->rs_mark_time[mdev->rs_last_mark] = jiffies;
+       }
+
+       if (os.conn == C_CONNECTED &&
+           (ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T)) {
+               unsigned long now = jiffies;
+               int i;
+
+               set_ov_position(mdev, ns.conn);
+               mdev->rs_start = now;
+               mdev->rs_last_events = 0;
+               mdev->rs_last_sect_ev = 0;
+               mdev->ov_last_oos_size = 0;
+               mdev->ov_last_oos_start = 0;
+
+               for (i = 0; i < DRBD_SYNC_MARKS; i++) {
+                       mdev->rs_mark_left[i] = mdev->ov_left;
+                       mdev->rs_mark_time[i] = now;
+               }
+
+               drbd_rs_controller_reset(mdev);
+
+               if (ns.conn == C_VERIFY_S) {
+                       dev_info(DEV, "Starting Online Verify from sector %llu\n",
+                                       (unsigned long long)mdev->ov_position);
+                       mod_timer(&mdev->resync_timer, jiffies);
+               }
+       }
+
+       if (get_ldev(mdev)) {
+               u32 mdf = mdev->ldev->md.flags & ~(MDF_CONSISTENT|MDF_PRIMARY_IND|
+                                                MDF_CONNECTED_IND|MDF_WAS_UP_TO_DATE|
+                                                MDF_PEER_OUT_DATED|MDF_CRASHED_PRIMARY);
+
+               if (test_bit(CRASHED_PRIMARY, &mdev->flags))
+                       mdf |= MDF_CRASHED_PRIMARY;
+               if (mdev->state.role == R_PRIMARY ||
+                   (mdev->state.pdsk < D_INCONSISTENT && mdev->state.peer == R_PRIMARY))
+                       mdf |= MDF_PRIMARY_IND;
+               if (mdev->state.conn > C_WF_REPORT_PARAMS)
+                       mdf |= MDF_CONNECTED_IND;
+               if (mdev->state.disk > D_INCONSISTENT)
+                       mdf |= MDF_CONSISTENT;
+               if (mdev->state.disk > D_OUTDATED)
+                       mdf |= MDF_WAS_UP_TO_DATE;
+               if (mdev->state.pdsk <= D_OUTDATED && mdev->state.pdsk >= D_INCONSISTENT)
+                       mdf |= MDF_PEER_OUT_DATED;
+               if (mdf != mdev->ldev->md.flags) {
+                       mdev->ldev->md.flags = mdf;
+                       drbd_md_mark_dirty(mdev);
+               }
+               if (os.disk < D_CONSISTENT && ns.disk >= D_CONSISTENT)
+                       drbd_set_ed_uuid(mdev, mdev->ldev->md.uuid[UI_CURRENT]);
+               put_ldev(mdev);
+       }
+
+       /* Peer was forced D_UP_TO_DATE & R_PRIMARY, consider to resync */
+       if (os.disk == D_INCONSISTENT && os.pdsk == D_INCONSISTENT &&
+           os.peer == R_SECONDARY && ns.peer == R_PRIMARY)
+               set_bit(CONSIDER_RESYNC, &mdev->flags);
+
+       /* Receiver should clean up itself */
+       if (os.conn != C_DISCONNECTING && ns.conn == C_DISCONNECTING)
+               drbd_thread_stop_nowait(&mdev->tconn->receiver);
+
+       /* Now the receiver finished cleaning up itself, it should die */
+       if (os.conn != C_STANDALONE && ns.conn == C_STANDALONE)
+               drbd_thread_stop_nowait(&mdev->tconn->receiver);
+
+       /* Upon network failure, we need to restart the receiver. */
+       if (os.conn > C_TEAR_DOWN &&
+           ns.conn <= C_TEAR_DOWN && ns.conn >= C_TIMEOUT)
+               drbd_thread_restart_nowait(&mdev->tconn->receiver);
+
+       /* Resume AL writing if we get a connection */
+       if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED)
+               drbd_resume_al(mdev);
+
+       ascw = kmalloc(sizeof(*ascw), GFP_ATOMIC);
+       if (ascw) {
+               ascw->os = os;
+               ascw->ns = ns;
+               ascw->flags = flags;
+               ascw->w.cb = w_after_state_ch;
+               ascw->done = done;
+               drbd_queue_work(&mdev->tconn->data.work, &ascw->w);
+       } else {
+               dev_warn(DEV, "Could not kmalloc an ascw\n");
+       }
+
+       return rv;
+}
+
+static int w_after_state_ch(struct drbd_conf *mdev, struct drbd_work *w, int unused)
+{
+       struct after_state_chg_work *ascw =
+               container_of(w, struct after_state_chg_work, w);
+
+       after_state_ch(mdev, ascw->os, ascw->ns, ascw->flags);
+       if (ascw->flags & CS_WAIT_COMPLETE) {
+               D_ASSERT(ascw->done != NULL);
+               complete(ascw->done);
+       }
+       kfree(ascw);
+
+       return 1;
+}
+
+static void abw_start_sync(struct drbd_conf *mdev, int rv)
+{
+       if (rv) {
+               dev_err(DEV, "Writing the bitmap failed not starting resync.\n");
+               _drbd_request_state(mdev, NS(conn, C_CONNECTED), CS_VERBOSE);
+               return;
+       }
+
+       switch (mdev->state.conn) {
+       case C_STARTING_SYNC_T:
+               _drbd_request_state(mdev, NS(conn, C_WF_SYNC_UUID), CS_VERBOSE);
+               break;
+       case C_STARTING_SYNC_S:
+               drbd_start_resync(mdev, C_SYNC_SOURCE);
+               break;
+       }
+}
+
+int drbd_bitmap_io_from_worker(struct drbd_conf *mdev,
+               int (*io_fn)(struct drbd_conf *),
+               char *why, enum bm_flag flags)
+{
+       int rv;
+
+       D_ASSERT(current == mdev->tconn->worker.task);
+
+       /* open coded non-blocking drbd_suspend_io(mdev); */
+       set_bit(SUSPEND_IO, &mdev->flags);
+
+       drbd_bm_lock(mdev, why, flags);
+       rv = io_fn(mdev);
+       drbd_bm_unlock(mdev);
+
+       drbd_resume_io(mdev);
+
+       return rv;
+}
+
+/**
+ * after_state_ch() - Perform after state change actions that may sleep
+ * @mdev:      DRBD device.
+ * @os:                old state.
+ * @ns:                new state.
+ * @flags:     Flags
+ */
+static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
+                          union drbd_state ns, enum chg_state_flags flags)
+{
+       enum drbd_fencing_p fp;
+       enum drbd_req_event what = NOTHING;
+       union drbd_state nsm = (union drbd_state){ .i = -1 };
+
+       if (os.conn != C_CONNECTED && ns.conn == C_CONNECTED) {
+               clear_bit(CRASHED_PRIMARY, &mdev->flags);
+               if (mdev->p_uuid)
+                       mdev->p_uuid[UI_FLAGS] &= ~((u64)2);
+       }
+
+       fp = FP_DONT_CARE;
+       if (get_ldev(mdev)) {
+               fp = mdev->ldev->dc.fencing;
+               put_ldev(mdev);
+       }
+
+       /* Inform userspace about the change... */
+       drbd_bcast_state(mdev, ns);
+
+       if (!(os.role == R_PRIMARY && os.disk < D_UP_TO_DATE && os.pdsk < D_UP_TO_DATE) &&
+           (ns.role == R_PRIMARY && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE))
+               drbd_khelper(mdev, "pri-on-incon-degr");
+
+       /* Here we have the actions that are performed after a
+          state change. This function might sleep */
+
+       nsm.i = -1;
+       if (ns.susp_nod) {
+               if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED)
+                       what = RESEND;
+
+               if (os.disk == D_ATTACHING && ns.disk > D_ATTACHING)
+                       what = RESTART_FROZEN_DISK_IO;
+
+               if (what != NOTHING)
+                       nsm.susp_nod = 0;
+       }
+
+       if (ns.susp_fen) {
+               /* case1: The outdate peer handler is successful: */
+               if (os.pdsk > D_OUTDATED  && ns.pdsk <= D_OUTDATED) {
+                       tl_clear(mdev);
+                       if (test_bit(NEW_CUR_UUID, &mdev->flags)) {
+                               drbd_uuid_new_current(mdev);
+                               clear_bit(NEW_CUR_UUID, &mdev->flags);
+                       }
+                       spin_lock_irq(&mdev->tconn->req_lock);
+                       _drbd_set_state(_NS(mdev, susp_fen, 0), CS_VERBOSE, NULL);
+                       spin_unlock_irq(&mdev->tconn->req_lock);
+               }
+               /* case2: The connection was established again: */
+               if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED) {
+                       clear_bit(NEW_CUR_UUID, &mdev->flags);
+                       what = RESEND;
+                       nsm.susp_fen = 0;
+               }
+       }
+
+       if (what != NOTHING) {
+               spin_lock_irq(&mdev->tconn->req_lock);
+               _tl_restart(mdev, what);
+               nsm.i &= mdev->state.i;
+               _drbd_set_state(mdev, nsm, CS_VERBOSE, NULL);
+               spin_unlock_irq(&mdev->tconn->req_lock);
+       }
+
+       /* Became sync source.  With protocol >= 96, we still need to send out
+        * the sync uuid now. Need to do that before any drbd_send_state, or
+        * the other side may go "paused sync" before receiving the sync uuids,
+        * which is unexpected. */
+       if ((os.conn != C_SYNC_SOURCE && os.conn != C_PAUSED_SYNC_S) &&
+           (ns.conn == C_SYNC_SOURCE || ns.conn == C_PAUSED_SYNC_S) &&
+           mdev->tconn->agreed_pro_version >= 96 && get_ldev(mdev)) {
+               drbd_gen_and_send_sync_uuid(mdev);
+               put_ldev(mdev);
+       }
+
+       /* Do not change the order of the if above and the two below... */
+       if (os.pdsk == D_DISKLESS && ns.pdsk > D_DISKLESS) {      /* attach on the peer */
+               drbd_send_uuids(mdev);
+               drbd_send_state(mdev);
+       }
+       /* No point in queuing send_bitmap if we don't have a connection
+        * anymore, so check also the _current_ state, not only the new state
+        * at the time this work was queued. */
+       if (os.conn != C_WF_BITMAP_S && ns.conn == C_WF_BITMAP_S &&
+           mdev->state.conn == C_WF_BITMAP_S)
+               drbd_queue_bitmap_io(mdev, &drbd_send_bitmap, NULL,
+                               "send_bitmap (WFBitMapS)",
+                               BM_LOCKED_TEST_ALLOWED);
+
+       /* Lost contact to peer's copy of the data */
+       if ((os.pdsk >= D_INCONSISTENT &&
+            os.pdsk != D_UNKNOWN &&
+            os.pdsk != D_OUTDATED)
+       &&  (ns.pdsk < D_INCONSISTENT ||
+            ns.pdsk == D_UNKNOWN ||
+            ns.pdsk == D_OUTDATED)) {
+               if (get_ldev(mdev)) {
+                       if ((ns.role == R_PRIMARY || ns.peer == R_PRIMARY) &&
+                           mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE) {
+                               if (is_susp(mdev->state)) {
+                                       set_bit(NEW_CUR_UUID, &mdev->flags);
+                               } else {
+                                       drbd_uuid_new_current(mdev);
+                                       drbd_send_uuids(mdev);
+                               }
+                       }
+                       put_ldev(mdev);
+               }
+       }
+
+       if (ns.pdsk < D_INCONSISTENT && get_ldev(mdev)) {
+               if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0) {
+                       drbd_uuid_new_current(mdev);
+                       drbd_send_uuids(mdev);
+               }
+
+               /* D_DISKLESS Peer becomes secondary */
+               if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
+                       /* We may still be Primary ourselves.
+                        * No harm done if the bitmap still changes,
+                        * redirtied pages will follow later. */
+                       drbd_bitmap_io_from_worker(mdev, &drbd_bm_write,
+                               "demote diskless peer", BM_LOCKED_SET_ALLOWED);
+               put_ldev(mdev);
+       }
+
+       /* Write out all changed bits on demote.
+        * Though, no need to da that just yet
+        * if there is a resync going on still */
+       if (os.role == R_PRIMARY && ns.role == R_SECONDARY &&
+               mdev->state.conn <= C_CONNECTED && get_ldev(mdev)) {
+               /* No changes to the bitmap expected this time, so assert that,
+                * even though no harm was done if it did change. */
+               drbd_bitmap_io_from_worker(mdev, &drbd_bm_write,
+                               "demote", BM_LOCKED_TEST_ALLOWED);
+               put_ldev(mdev);
+       }
+
+       /* Last part of the attaching process ... */
+       if (ns.conn >= C_CONNECTED &&
+           os.disk == D_ATTACHING && ns.disk == D_NEGOTIATING) {
+               drbd_send_sizes(mdev, 0, 0);  /* to start sync... */
+               drbd_send_uuids(mdev);
+               drbd_send_state(mdev);
+       }
+
+       /* We want to pause/continue resync, tell peer. */
+       if (ns.conn >= C_CONNECTED &&
+            ((os.aftr_isp != ns.aftr_isp) ||
+             (os.user_isp != ns.user_isp)))
+               drbd_send_state(mdev);
+
+       /* In case one of the isp bits got set, suspend other devices. */
+       if ((!os.aftr_isp && !os.peer_isp && !os.user_isp) &&
+           (ns.aftr_isp || ns.peer_isp || ns.user_isp))
+               suspend_other_sg(mdev);
+
+       /* Make sure the peer gets informed about eventual state
+          changes (ISP bits) while we were in WFReportParams. */
+       if (os.conn == C_WF_REPORT_PARAMS && ns.conn >= C_CONNECTED)
+               drbd_send_state(mdev);
+
+       if (os.conn != C_AHEAD && ns.conn == C_AHEAD)
+               drbd_send_state(mdev);
+
+       /* We are in the progress to start a full sync... */
+       if ((os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
+           (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S))
+               /* no other bitmap changes expected during this phase */
+               drbd_queue_bitmap_io(mdev,
+                       &drbd_bmio_set_n_write, &abw_start_sync,
+                       "set_n_write from StartingSync", BM_LOCKED_TEST_ALLOWED);
+
+       /* We are invalidating our self... */
+       if (os.conn < C_CONNECTED && ns.conn < C_CONNECTED &&
+           os.disk > D_INCONSISTENT && ns.disk == D_INCONSISTENT)
+               /* other bitmap operation expected during this phase */
+               drbd_queue_bitmap_io(mdev, &drbd_bmio_set_n_write, NULL,
+                       "set_n_write from invalidate", BM_LOCKED_MASK);
+
+       /* first half of local IO error, failure to attach,
+        * or administrative detach */
+       if (os.disk != D_FAILED && ns.disk == D_FAILED) {
+               enum drbd_io_error_p eh;
+               int was_io_error;
+               /* corresponding get_ldev was in __drbd_set_state, to serialize
+                * our cleanup here with the transition to D_DISKLESS,
+                * so it is safe to dreference ldev here. */
+               eh = mdev->ldev->dc.on_io_error;
+               was_io_error = test_and_clear_bit(WAS_IO_ERROR, &mdev->flags);
+
+               /* current state still has to be D_FAILED,
+                * there is only one way out: to D_DISKLESS,
+                * and that may only happen after our put_ldev below. */
+               if (mdev->state.disk != D_FAILED)
+                       dev_err(DEV,
+                               "ASSERT FAILED: disk is %s during detach\n",
+                               drbd_disk_str(mdev->state.disk));
+
+               if (drbd_send_state(mdev))
+                       dev_warn(DEV, "Notified peer that I am detaching my disk\n");
+               else
+                       dev_err(DEV, "Sending state for detaching disk failed\n");
+
+               drbd_rs_cancel_all(mdev);
+
+               /* In case we want to get something to stable storage still,
+                * this may be the last chance.
+                * Following put_ldev may transition to D_DISKLESS. */
+               drbd_md_sync(mdev);
+               put_ldev(mdev);
+
+               if (was_io_error && eh == EP_CALL_HELPER)
+                       drbd_khelper(mdev, "local-io-error");
+       }
+
+        /* second half of local IO error, failure to attach,
+         * or administrative detach,
+         * after local_cnt references have reached zero again */
+        if (os.disk != D_DISKLESS && ns.disk == D_DISKLESS) {
+                /* We must still be diskless,
+                 * re-attach has to be serialized with this! */
+                if (mdev->state.disk != D_DISKLESS)
+                        dev_err(DEV,
+                                "ASSERT FAILED: disk is %s while going diskless\n",
+                                drbd_disk_str(mdev->state.disk));
+
+                mdev->rs_total = 0;
+                mdev->rs_failed = 0;
+                atomic_set(&mdev->rs_pending_cnt, 0);
+
+               if (drbd_send_state(mdev))
+                       dev_warn(DEV, "Notified peer that I'm now diskless.\n");
+               /* corresponding get_ldev in __drbd_set_state
+                * this may finally trigger drbd_ldev_destroy. */
+               put_ldev(mdev);
+       }
+
+       /* Notify peer that I had a local IO error, and did not detached.. */
+       if (os.disk == D_UP_TO_DATE && ns.disk == D_INCONSISTENT)
+               drbd_send_state(mdev);
+
+       /* Disks got bigger while they were detached */
+       if (ns.disk > D_NEGOTIATING && ns.pdsk > D_NEGOTIATING &&
+           test_and_clear_bit(RESYNC_AFTER_NEG, &mdev->flags)) {
+               if (ns.conn == C_CONNECTED)
+                       resync_after_online_grow(mdev);
+       }
+
+       /* A resync finished or aborted, wake paused devices... */
+       if ((os.conn > C_CONNECTED && ns.conn <= C_CONNECTED) ||
+           (os.peer_isp && !ns.peer_isp) ||
+           (os.user_isp && !ns.user_isp))
+               resume_next_sg(mdev);
+
+       /* sync target done with resync.  Explicitly notify peer, even though
+        * it should (at least for non-empty resyncs) already know itself. */
+       if (os.disk < D_UP_TO_DATE && os.conn >= C_SYNC_SOURCE && ns.conn == C_CONNECTED)
+               drbd_send_state(mdev);
+
+       /* This triggers bitmap writeout of potentially still unwritten pages
+        * if the resync finished cleanly, or aborted because of peer disk
+        * failure, or because of connection loss.
+        * For resync aborted because of local disk failure, we cannot do
+        * any bitmap writeout anymore.
+        * No harm done if some bits change during this phase.
+        */
+       if (os.conn > C_CONNECTED && ns.conn <= C_CONNECTED && get_ldev(mdev)) {
+               drbd_queue_bitmap_io(mdev, &drbd_bm_write, NULL,
+                       "write from resync_finished", BM_LOCKED_SET_ALLOWED);
+               put_ldev(mdev);
+       }
+
+       if (ns.disk == D_DISKLESS &&
+           ns.conn == C_STANDALONE &&
+           ns.role == R_SECONDARY) {
+               if (os.aftr_isp != ns.aftr_isp)
+                       resume_next_sg(mdev);
+       }
+
+       after_conn_state_ch(mdev->tconn, os, ns, flags);
+       drbd_md_sync(mdev);
+}
+
+static void after_conn_state_ch(struct drbd_tconn *tconn, union drbd_state os,
+                               union drbd_state ns, enum chg_state_flags flags)
+{
+       /* Upon network configuration, we need to start the receiver */
+       if (os.conn == C_STANDALONE && ns.conn == C_UNCONNECTED)
+               drbd_thread_start(&tconn->receiver);
+
+       if (ns.disk == D_DISKLESS &&
+           ns.conn == C_STANDALONE &&
+           ns.role == R_SECONDARY) {
+               /* if (test_bit(DEVICE_DYING, &mdev->flags)) TODO: DEVICE_DYING functionality */
+               drbd_thread_stop_nowait(&tconn->worker);
+       }
+}
diff --git a/drivers/block/drbd/drbd_state.h b/drivers/block/drbd/drbd_state.h
new file mode 100644 (file)
index 0000000..3ec26e2
--- /dev/null
@@ -0,0 +1,101 @@
+#ifndef DRBD_STATE_H
+#define DRBD_STATE_H
+
+struct drbd_conf;
+
+/**
+ * DOC: DRBD State macros
+ *
+ * These macros are used to express state changes in easily readable form.
+ *
+ * The NS macros expand to a mask and a value, that can be bit ored onto the
+ * current state as soon as the spinlock (req_lock) was taken.
+ *
+ * The _NS macros are used for state functions that get called with the
+ * spinlock. These macros expand directly to the new state value.
+ *
+ * Besides the basic forms NS() and _NS() additional _?NS[23] are defined
+ * to express state changes that affect more than one aspect of the state.
+ *
+ * E.g. NS2(conn, C_CONNECTED, peer, R_SECONDARY)
+ * Means that the network connection was established and that the peer
+ * is in secondary role.
+ */
+#define role_MASK R_MASK
+#define peer_MASK R_MASK
+#define disk_MASK D_MASK
+#define pdsk_MASK D_MASK
+#define conn_MASK C_MASK
+#define susp_MASK 1
+#define user_isp_MASK 1
+#define aftr_isp_MASK 1
+#define susp_nod_MASK 1
+#define susp_fen_MASK 1
+
+#define NS(T, S) \
+       ({ union drbd_state mask; mask.i = 0; mask.T = T##_MASK; mask; }), \
+       ({ union drbd_state val; val.i = 0; val.T = (S); val; })
+#define NS2(T1, S1, T2, S2) \
+       ({ union drbd_state mask; mask.i = 0; mask.T1 = T1##_MASK; \
+         mask.T2 = T2##_MASK; mask; }), \
+       ({ union drbd_state val; val.i = 0; val.T1 = (S1); \
+         val.T2 = (S2); val; })
+#define NS3(T1, S1, T2, S2, T3, S3) \
+       ({ union drbd_state mask; mask.i = 0; mask.T1 = T1##_MASK; \
+         mask.T2 = T2##_MASK; mask.T3 = T3##_MASK; mask; }), \
+       ({ union drbd_state val;  val.i = 0; val.T1 = (S1); \
+         val.T2 = (S2); val.T3 = (S3); val; })
+
+#define _NS(D, T, S) \
+       D, ({ union drbd_state __ns; __ns.i = D->state.i; __ns.T = (S); __ns; })
+#define _NS2(D, T1, S1, T2, S2) \
+       D, ({ union drbd_state __ns; __ns.i = D->state.i; __ns.T1 = (S1); \
+       __ns.T2 = (S2); __ns; })
+#define _NS3(D, T1, S1, T2, S2, T3, S3) \
+       D, ({ union drbd_state __ns; __ns.i = D->state.i; __ns.T1 = (S1); \
+       __ns.T2 = (S2); __ns.T3 = (S3); __ns; })
+
+enum chg_state_flags {
+       CS_HARD = 1,
+       CS_VERBOSE = 2,
+       CS_WAIT_COMPLETE = 4,
+       CS_SERIALIZE    = 8,
+       CS_ORDERED      = CS_WAIT_COMPLETE + CS_SERIALIZE,
+};
+
+extern enum drbd_state_rv drbd_change_state(struct drbd_conf *mdev,
+                                           enum chg_state_flags f,
+                                           union drbd_state mask,
+                                           union drbd_state val);
+extern void drbd_force_state(struct drbd_conf *, union drbd_state,
+                       union drbd_state);
+extern enum drbd_state_rv _drbd_request_state(struct drbd_conf *,
+                                             union drbd_state,
+                                             union drbd_state,
+                                             enum chg_state_flags);
+extern enum drbd_state_rv __drbd_set_state(struct drbd_conf *, union drbd_state,
+                                          enum chg_state_flags,
+                                          struct completion *done);
+extern void print_st_err(struct drbd_conf *, union drbd_state,
+                       union drbd_state, int);
+
+extern void drbd_resume_al(struct drbd_conf *mdev);
+
+/**
+ * drbd_request_state() - Reqest a state change
+ * @mdev:      DRBD device.
+ * @mask:      mask of state bits to change.
+ * @val:       value of new state bits.
+ *
+ * This is the most graceful way of requesting a state change. It is verbose
+ * quite verbose in case the state change is not possible, and all those
+ * state changes are globally serialized.
+ */
+static inline int drbd_request_state(struct drbd_conf *mdev,
+                                    union drbd_state mask,
+                                    union drbd_state val)
+{
+       return _drbd_request_state(mdev, mask, val, CS_VERBOSE + CS_ORDERED);
+}
+
+#endif
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