5 files changed, 115 insertions, 63 deletions

diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 25428bc28476..b62dd5f26c5d 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -104,26 +104,16 @@ struct drbd_bitmap {
 
         wait_queue_head_t bm_io_wait; /* used to serialize IO of single pages */
 
-        unsigned long  bm_flags;
+        enum bm_flag bm_flags;
 
         /* debugging aid, in case we are still racy somewhere */
         char          *bm_why;
         struct task_struct *bm_task;
 };
 
-/* definition of bits in bm_flags */
-#define BM_LOCKED       0
-// #define BM_MD_IO_ERROR  1 unused now.
-#define BM_P_VMALLOCED  2
-
 static int __bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
                                unsigned long e, int val, const enum km_type km);
 
-static int bm_is_locked(struct drbd_bitmap *b)
-{
-        return test_bit(BM_LOCKED, &b->bm_flags);
-}
-
 #define bm_print_lock_info(m) __bm_print_lock_info(m, __func__)
 static void __bm_print_lock_info(struct drbd_conf *mdev, const char *func)
 {
@@ -140,7 +130,7 @@ static void __bm_print_lock_info(struct drbd_conf *mdev, const char *func)
             b->bm_task == mdev->worker.task   ? "worker"   : "?");
 }
 
-void drbd_bm_lock(struct drbd_conf *mdev, char *why)
+void drbd_bm_lock(struct drbd_conf *mdev, char *why, enum bm_flag flags)
 {
         struct drbd_bitmap *b = mdev->bitmap;
         int trylock_failed;
@@ -163,8 +153,9 @@ void drbd_bm_lock(struct drbd_conf *mdev, char *why)
                     b->bm_task == mdev->worker.task   ? "worker"   : "?");
                 mutex_lock(&b->bm_change);
         }
-        if (__test_and_set_bit(BM_LOCKED, &b->bm_flags))
+        if (BM_LOCKED_MASK & b->bm_flags)
                 dev_err(DEV, "FIXME bitmap already locked in bm_lock\n");
+        b->bm_flags |= flags & BM_LOCKED_MASK;
 
         b->bm_why  = why;
         b->bm_task = current;
@@ -178,9 +169,10 @@ void drbd_bm_unlock(struct drbd_conf *mdev)
                 return;
         }
 
-        if (!__test_and_clear_bit(BM_LOCKED, &mdev->bitmap->bm_flags))
+        if (!(BM_LOCKED_MASK & mdev->bitmap->bm_flags))
                 dev_err(DEV, "FIXME bitmap not locked in bm_unlock\n");
 
+        b->bm_flags &= ~BM_LOCKED_MASK;
         b->bm_why  = NULL;
         b->bm_task = NULL;
         mutex_unlock(&b->bm_change);
@@ -421,9 +413,9 @@ static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want)
         }
 
         if (vmalloced)
-                set_bit(BM_P_VMALLOCED, &b->bm_flags);
+                b->bm_flags |= BM_P_VMALLOCED;
         else
-                clear_bit(BM_P_VMALLOCED, &b->bm_flags);
+                b->bm_flags &= ~BM_P_VMALLOCED;
 
         return new_pages;
 }
@@ -460,7 +452,7 @@ void drbd_bm_cleanup(struct drbd_conf *mdev)
 {
         ERR_IF (!mdev->bitmap) return;
         bm_free_pages(mdev->bitmap->bm_pages, mdev->bitmap->bm_number_of_pages);
-        bm_vk_free(mdev->bitmap->bm_pages, test_bit(BM_P_VMALLOCED, &mdev->bitmap->bm_flags));
+        bm_vk_free(mdev->bitmap->bm_pages, (BM_P_VMALLOCED & mdev->bitmap->bm_flags));
         kfree(mdev->bitmap);
         mdev->bitmap = NULL;
 }
@@ -623,7 +615,7 @@ int drbd_bm_resize(struct drbd_conf *mdev, sector_t capacity, int set_new_bits)
 
         ERR_IF(!b) return -ENOMEM;
 
-        drbd_bm_lock(mdev, "resize");
+        drbd_bm_lock(mdev, "resize", BM_LOCKED_MASK);
 
         dev_info(DEV, "drbd_bm_resize called with capacity == %llu\n",
                         (unsigned long long)capacity);
@@ -631,7 +623,7 @@ int drbd_bm_resize(struct drbd_conf *mdev, sector_t capacity, int set_new_bits)
         if (capacity == b->bm_dev_capacity)
                 goto out;
 
-        opages_vmalloced = test_bit(BM_P_VMALLOCED, &b->bm_flags);
+        opages_vmalloced = (BM_P_VMALLOCED & b->bm_flags);
 
         if (capacity == 0) {
                 spin_lock_irq(&b->bm_lock);
@@ -1030,7 +1022,7 @@ static int bm_rw(struct drbd_conf *mdev, int rw, unsigned lazy_writeout_upper_id
          * as we submit copies of pages anyways.
          */
         if (!ctx.flags)
-                WARN_ON(!bm_is_locked(b));
+                WARN_ON(!(BM_LOCKED_MASK & b->bm_flags));
 
         num_pages = b->bm_number_of_pages;
 
@@ -1220,7 +1212,7 @@ static unsigned long bm_find_next(struct drbd_conf *mdev,
         ERR_IF(!b->bm_pages) return i;
 
         spin_lock_irq(&b->bm_lock);
-        if (bm_is_locked(b))
+        if (BM_DONT_TEST & b->bm_flags)
                 bm_print_lock_info(mdev);
 
         i = __bm_find_next(mdev, bm_fo, find_zero_bit, KM_IRQ1);
@@ -1246,13 +1238,13 @@ unsigned long drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo
  * you must take drbd_bm_lock() first */
 unsigned long _drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo)
 {
-        /* WARN_ON(!bm_is_locked(mdev)); */
+        /* WARN_ON(!(BM_DONT_SET & mdev->b->bm_flags)); */
         return __bm_find_next(mdev, bm_fo, 0, KM_USER1);
 }
 
 unsigned long _drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo)
 {
-        /* WARN_ON(!bm_is_locked(mdev)); */
+        /* WARN_ON(!(BM_DONT_SET & mdev->b->bm_flags)); */
         return __bm_find_next(mdev, bm_fo, 1, KM_USER1);
 }
 
@@ -1322,7 +1314,7 @@ static int bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
         ERR_IF(!b->bm_pages) return 0;
 
         spin_lock_irqsave(&b->bm_lock, flags);
-        if (bm_is_locked(b))
+        if ((val ? BM_DONT_SET : BM_DONT_CLEAR) & b->bm_flags)
                 bm_print_lock_info(mdev);
 
         c = __bm_change_bits_to(mdev, s, e, val, KM_IRQ1);
@@ -1439,7 +1431,7 @@ int drbd_bm_test_bit(struct drbd_conf *mdev, const unsigned long bitnr)
         ERR_IF(!b->bm_pages) return 0;
 
         spin_lock_irqsave(&b->bm_lock, flags);
-        if (bm_is_locked(b))
+        if (BM_DONT_TEST & b->bm_flags)
                 bm_print_lock_info(mdev);
         if (bitnr < b->bm_bits) {
                 p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr));
@@ -1474,7 +1466,7 @@ int drbd_bm_count_bits(struct drbd_conf *mdev, const unsigned long s, const unsi
         ERR_IF(!b->bm_pages) return 1;
 
         spin_lock_irqsave(&b->bm_lock, flags);
-        if (bm_is_locked(b))
+        if (BM_DONT_TEST & b->bm_flags)
                 bm_print_lock_info(mdev);
         for (bitnr = s; bitnr <= e; bitnr++) {
                 unsigned int idx = bm_bit_to_page_idx(b, bitnr);
@@ -1522,7 +1514,7 @@ int drbd_bm_e_weight(struct drbd_conf *mdev, unsigned long enr)
         ERR_IF(!b->bm_pages) return 0;
 
         spin_lock_irqsave(&b->bm_lock, flags);
-        if (bm_is_locked(b))
+        if (BM_DONT_TEST & b->bm_flags)
                 bm_print_lock_info(mdev);
 
         s = S2W(enr);
@@ -1555,7 +1547,7 @@ unsigned long drbd_bm_ALe_set_all(struct drbd_conf *mdev, unsigned long al_enr)
         ERR_IF(!b->bm_pages) return 0;
 
         spin_lock_irq(&b->bm_lock);
-        if (bm_is_locked(b))
+        if (BM_DONT_SET & b->bm_flags)
                 bm_print_lock_info(mdev);
         weight = b->bm_set;
 
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 0a9059eb94db..267d9897ca8c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -855,6 +855,32 @@ enum {
 
 struct drbd_bitmap; /* opaque for drbd_conf */
 
+/* definition of bits in bm_flags to be used in drbd_bm_lock
+ * and drbd_bitmap_io and friends. */
+enum bm_flag {
+        /* do we need to kfree, or vfree bm_pages? */
+        BM_P_VMALLOCED = 0x10000, /* internal use only, will be masked out */
+
+        /* currently locked for bulk operation */
+        BM_LOCKED_MASK = 0x7,
+
+        /* in detail, that is: */
+        BM_DONT_CLEAR = 0x1,
+        BM_DONT_SET   = 0x2,
+        BM_DONT_TEST  = 0x4,
+
+        /* (test bit, count bit) allowed (common case) */
+        BM_LOCKED_TEST_ALLOWED = 0x3,
+
+        /* testing bits, as well as setting new bits allowed, but clearing bits
+         * would be unexpected.  Used during bitmap receive.  Setting new bits
+         * requires sending of "out-of-sync" information, though. */
+        BM_LOCKED_SET_ALLOWED = 0x1,
+
+        /* clear is not expected while bitmap is locked for bulk operation */
+};
+
+
 /* TODO sort members for performance
  * MAYBE group them further */
 
@@ -920,6 +946,7 @@ struct drbd_md_io {
 struct bm_io_work {
         struct drbd_work w;
         char *why;
+        enum bm_flag flags;
         int (*io_fn)(struct drbd_conf *mdev);
         void (*done)(struct drbd_conf *mdev, int rv);
 };
@@ -1242,7 +1269,6 @@ extern void drbd_free_bc(struct drbd_backing_dev *ldev);
 extern void drbd_mdev_cleanup(struct drbd_conf *mdev);
 void drbd_print_uuids(struct drbd_conf *mdev, const char *text);
 
-/* drbd_meta-data.c (still in drbd_main.c) */
 extern void drbd_md_sync(struct drbd_conf *mdev);
 extern int  drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev);
 extern void drbd_uuid_set(struct drbd_conf *mdev, int idx, u64 val) __must_hold(local);
@@ -1263,10 +1289,12 @@ extern void drbd_md_mark_dirty_(struct drbd_conf *mdev,
 extern void drbd_queue_bitmap_io(struct drbd_conf *mdev,
                                  int (*io_fn)(struct drbd_conf *),
                                  void (*done)(struct drbd_conf *, int),
-                                 char *why);
+                                 char *why, enum bm_flag flags);
+extern int drbd_bitmap_io(struct drbd_conf *mdev,
+                int (*io_fn)(struct drbd_conf *),
+                char *why, enum bm_flag flags);
 extern int drbd_bmio_set_n_write(struct drbd_conf *mdev);
 extern int drbd_bmio_clear_n_write(struct drbd_conf *mdev);
-extern int drbd_bitmap_io(struct drbd_conf *mdev, int (*io_fn)(struct drbd_conf *), char *why);
 extern void drbd_go_diskless(struct drbd_conf *mdev);
 extern void drbd_ldev_destroy(struct drbd_conf *mdev);
 
@@ -1452,7 +1480,7 @@ extern void drbd_bm_merge_lel(struct drbd_conf *mdev, size_t offset,
 extern void drbd_bm_get_lel(struct drbd_conf *mdev, size_t offset,
                 size_t number, unsigned long *buffer);
 
-extern void drbd_bm_lock(struct drbd_conf *mdev, char *why);
+extern void drbd_bm_lock(struct drbd_conf *mdev, char *why, enum bm_flag flags);
 extern void drbd_bm_unlock(struct drbd_conf *mdev);
 /* drbd_main.c */
 
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index b68332a0e73e..a9e9b496e73b 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1320,7 +1320,9 @@ static void abw_start_sync(struct drbd_conf *mdev, int rv)
         }
 }
 
-int drbd_bitmap_io_from_worker(struct drbd_conf *mdev, int (*io_fn)(struct drbd_conf *), char *why)
+int drbd_bitmap_io_from_worker(struct drbd_conf *mdev,
+                int (*io_fn)(struct drbd_conf *),
+                char *why, enum bm_flag flags)
 {
         int rv;
 
@@ -1328,10 +1330,8 @@ int drbd_bitmap_io_from_worker(struct drbd_conf *mdev, int (*io_fn)(struct drbd_
 
         /* open coded non-blocking drbd_suspend_io(mdev); */
         set_bit(SUSPEND_IO, &mdev->flags);
-        if (!is_susp(mdev->state))
-                D_ASSERT(atomic_read(&mdev->ap_bio_cnt) == 0);
 
-        drbd_bm_lock(mdev, why);
+        drbd_bm_lock(mdev, why, flags);
         rv = io_fn(mdev);
         drbd_bm_unlock(mdev);
 
@@ -1438,7 +1438,8 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
         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)");
+                                "send_bitmap (WFBitMapS)",
+                                BM_LOCKED_TEST_ALLOWED);
 
         /* Lost contact to peer's copy of the data */
         if ((os.pdsk >= D_INCONSISTENT &&
@@ -1469,7 +1470,11 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 
                 /* D_DISKLESS Peer becomes secondary */
                 if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
-                        drbd_bitmap_io_from_worker(mdev, &drbd_bm_write, "demote diskless peer");
+                        /* 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);
         }
 
@@ -1478,7 +1483,10 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
          * 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)) {
-                drbd_bitmap_io_from_worker(mdev, &drbd_bm_write, "demote");
+                /* 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);
         }
 
@@ -1512,12 +1520,17 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
         /* 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))
-                drbd_queue_bitmap_io(mdev, &drbd_bmio_set_n_write, &abw_start_sync, "set_n_write from StartingSync");
+                /* 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)
-                drbd_queue_bitmap_io(mdev, &drbd_bmio_set_n_write, NULL, "set_n_write from invalidate");
+                /* 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 */
@@ -1599,14 +1612,14 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 
         /* This triggers bitmap writeout of potentially still unwritten pages
          * if the resync finished cleanly, or aborted because of peer disk
-         * failure.  Resync aborted because of connection failure does bitmap
-         * writeout from drbd_disconnect.
+         * 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 &&
-            mdev->state.conn == C_CONNECTED && get_ldev(mdev)) {
-                drbd_queue_bitmap_io(mdev, &drbd_bm_write, NULL, "write from resync_finished");
+        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);
         }
 
@@ -3929,7 +3942,7 @@ static int w_bitmap_io(struct drbd_conf *mdev, struct drbd_work *w, int unused)
         D_ASSERT(atomic_read(&mdev->ap_bio_cnt) == 0);
 
         if (get_ldev(mdev)) {
-                drbd_bm_lock(mdev, work->why);
+                drbd_bm_lock(mdev, work->why, work->flags);
                 rv = work->io_fn(mdev);
                 drbd_bm_unlock(mdev);
                 put_ldev(mdev);
@@ -3944,6 +3957,7 @@ static int w_bitmap_io(struct drbd_conf *mdev, struct drbd_work *w, int unused)
 
         clear_bit(BITMAP_IO_QUEUED, &mdev->flags);
         work->why = NULL;
+        work->flags = 0;
 
         return 1;
 }
@@ -3998,7 +4012,7 @@ void drbd_go_diskless(struct drbd_conf *mdev)
 void drbd_queue_bitmap_io(struct drbd_conf *mdev,
                           int (*io_fn)(struct drbd_conf *),
                           void (*done)(struct drbd_conf *, int),
-                          char *why)
+                          char *why, enum bm_flag flags)
 {
         D_ASSERT(current == mdev->worker.task);
 
@@ -4012,6 +4026,7 @@ void drbd_queue_bitmap_io(struct drbd_conf *mdev,
         mdev->bm_io_work.io_fn = io_fn;
         mdev->bm_io_work.done = done;
         mdev->bm_io_work.why = why;
+        mdev->bm_io_work.flags = flags;
 
         spin_lock_irq(&mdev->req_lock);
         set_bit(BITMAP_IO, &mdev->flags);
@@ -4031,19 +4046,22 @@ void drbd_queue_bitmap_io(struct drbd_conf *mdev,
  * freezes application IO while that the actual IO operations runs. This
  * functions MAY NOT be called from worker context.
  */
-int drbd_bitmap_io(struct drbd_conf *mdev, int (*io_fn)(struct drbd_conf *), char *why)
+int drbd_bitmap_io(struct drbd_conf *mdev, int (*io_fn)(struct drbd_conf *),
+                char *why, enum bm_flag flags)
 {
         int rv;
 
         D_ASSERT(current != mdev->worker.task);
 
-        drbd_suspend_io(mdev);
+        if ((flags & BM_LOCKED_SET_ALLOWED) == 0)
+                drbd_suspend_io(mdev);
 
-        drbd_bm_lock(mdev, why);
+        drbd_bm_lock(mdev, why, flags);
         rv = io_fn(mdev);
         drbd_bm_unlock(mdev);
 
-        drbd_resume_io(mdev);
+        if ((flags & BM_LOCKED_SET_ALLOWED) == 0)
+                drbd_resume_io(mdev);
 
         return rv;
 }
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index ce6f2fe80852..bc0bcb964603 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -648,7 +648,9 @@ enum determine_dev_size drbd_determin_dev_size(struct drbd_conf *mdev, enum dds_
                 dev_info(DEV, "Writing the whole bitmap, %s\n",
                          la_size_changed && md_moved ? "size changed and md moved" :
                          la_size_changed ? "size changed" : "md moved");
-                err = drbd_bitmap_io(mdev, &drbd_bm_write, "size changed"); /* does drbd_resume_io() ! */
+                /* next line implicitly does drbd_suspend_io()+drbd_resume_io() */
+                err = drbd_bitmap_io(mdev, &drbd_bm_write,
+                                "size changed", BM_LOCKED_MASK);
                 if (err) {
                         rv = dev_size_error;
                         goto out;
@@ -1160,12 +1162,14 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         if (drbd_md_test_flag(mdev->ldev, MDF_FULL_SYNC)) {
                 dev_info(DEV, "Assuming that all blocks are out of sync "
                      "(aka FullSync)\n");
-                if (drbd_bitmap_io(mdev, &drbd_bmio_set_n_write, "set_n_write from attaching")) {
+                if (drbd_bitmap_io(mdev, &drbd_bmio_set_n_write,
+                        "set_n_write from attaching", BM_LOCKED_MASK)) {
                         retcode = ERR_IO_MD_DISK;
                         goto force_diskless_dec;
                 }
         } else {
-                if (drbd_bitmap_io(mdev, &drbd_bm_read, "read from attaching") < 0) {
+                if (drbd_bitmap_io(mdev, &drbd_bm_read,
+                        "read from attaching", BM_LOCKED_MASK) < 0) {
                         retcode = ERR_IO_MD_DISK;
                         goto force_diskless_dec;
                 }
@@ -1173,7 +1177,8 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
 
         if (cp_discovered) {
                 drbd_al_apply_to_bm(mdev);
-                if (drbd_bitmap_io(mdev, &drbd_bm_write, "crashed primary apply AL")) {
+                if (drbd_bitmap_io(mdev, &drbd_bm_write,
+                        "crashed primary apply AL", BM_LOCKED_MASK)) {
                         retcode = ERR_IO_MD_DISK;
                         goto force_diskless_dec;
                 }
@@ -1925,7 +1930,8 @@ static int drbd_nl_invalidate_peer(struct drbd_conf *mdev, struct drbd_nl_cfg_re
                         retcode = drbd_request_state(mdev, NS(pdsk, D_INCONSISTENT));
                         if (retcode >= SS_SUCCESS) {
                                 if (drbd_bitmap_io(mdev, &drbd_bmio_set_susp_al,
-                                                   "set_n_write from invalidate_peer"))
+                                        "set_n_write from invalidate_peer",
+                                        BM_LOCKED_SET_ALLOWED))
                                         retcode = ERR_IO_MD_DISK;
                         }
                 } else
@@ -2143,7 +2149,8 @@ static int drbd_nl_new_c_uuid(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nl
         drbd_uuid_new_current(mdev); /* New current, previous to UI_BITMAP */
 
         if (args.clear_bm) {
-                err = drbd_bitmap_io(mdev, &drbd_bmio_clear_n_write, "clear_n_write from new_c_uuid");
+                err = drbd_bitmap_io(mdev, &drbd_bmio_clear_n_write,
+                        "clear_n_write from new_c_uuid", BM_LOCKED_MASK);
                 if (err) {
                         dev_err(DEV, "Writing bitmap failed with %d\n",err);
                         retcode = ERR_IO_MD_DISK;
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index e5686a81f42c..e13134f83fae 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2599,7 +2599,8 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_conf *mdev, enum drbd_rol
 
         if (abs(hg) >= 2) {
                 dev_info(DEV, "Writing the whole bitmap, full sync required after drbd_sync_handshake.\n");
-                if (drbd_bitmap_io(mdev, &drbd_bmio_set_n_write, "set_n_write from sync_handshake"))
+                if (drbd_bitmap_io(mdev, &drbd_bmio_set_n_write, "set_n_write from sync_handshake",
+                                        BM_LOCKED_SET_ALLOWED))
                         return C_MASK;
         }
 
@@ -3053,7 +3054,8 @@ static int receive_uuids(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned
                 if (skip_initial_sync) {
                         dev_info(DEV, "Accepted new current UUID, preparing to skip initial sync\n");
                         drbd_bitmap_io(mdev, &drbd_bmio_clear_n_write,
-                                        "clear_n_write from receive_uuids");
+                                        "clear_n_write from receive_uuids",
+                                        BM_LOCKED_TEST_ALLOWED);
                         _drbd_uuid_set(mdev, UI_CURRENT, p_uuid[UI_CURRENT]);
                         _drbd_uuid_set(mdev, UI_BITMAP, 0);
                         _drbd_set_state(_NS2(mdev, disk, D_UP_TO_DATE, pdsk, D_UP_TO_DATE),
@@ -3494,7 +3496,9 @@ static int receive_bitmap(struct drbd_conf *mdev, enum drbd_packets cmd, unsigne
         int ok = false;
         struct p_header80 *h = &mdev->data.rbuf.header.h80;
 
-        /* drbd_bm_lock(mdev, "receive bitmap"); By intention no bm_lock */
+        drbd_bm_lock(mdev, "receive bitmap", BM_LOCKED_SET_ALLOWED);
+        /* you are supposed to send additional out-of-sync information
+         * if you actually set bits during this phase */
 
         /* maybe we should use some per thread scratch page,
          * and allocate that during initial device creation? */
@@ -3568,7 +3572,7 @@ static int receive_bitmap(struct drbd_conf *mdev, enum drbd_packets cmd, unsigne
 
         ok = true;
  out:
-        /* drbd_bm_unlock(mdev); by intention no lock */
+        drbd_bm_unlock(mdev);
         if (ok && mdev->state.conn == C_WF_BITMAP_S)
                 drbd_start_resync(mdev, C_SYNC_SOURCE);
         free_page((unsigned long) buffer);
@@ -3817,7 +3821,6 @@ static void drbd_disconnect(struct drbd_conf *mdev)
 
         fp = FP_DONT_CARE;
         if (get_ldev(mdev)) {
-                drbd_bitmap_io(mdev, &drbd_bm_write, "write from disconnect");
                 fp = mdev->ldev->dc.fencing;
                 put_ldev(mdev);
         }
@@ -3846,6 +3849,10 @@ static void drbd_disconnect(struct drbd_conf *mdev)
                 drbd_request_state(mdev, NS(conn, C_STANDALONE));
         }
 
+        /* serialize with bitmap writeout triggered by the state change,
+         * if any. */
+        wait_event(mdev->misc_wait, !test_bit(BITMAP_IO, &mdev->flags));
+
         /* tcp_close and release of sendpage pages can be deferred.  I don't
          * want to use SO_LINGER, because apparently it can be deferred for
          * more than 20 seconds (longest time I checked).