Merge branch 'for-jens' of git://git.drbd.org/linux-drbd into for-3.5/drivers

Philipp writes:

This are the updates we have in the drbd-8.3 tree. They are intended
for your "for-3.5/drivers" drivers branch.

These changes include one new feature:
 * Allow detach from frozen backing devices with the new --force option;
   configurable timeout for backing devices by the new disk-timeout option

And huge number of bug fixes:
 * Fixed a write ordering problem on SyncTarget nodes for a write
   to a block that gets resynced at the same time. The bug can
   only be triggered with a device that has a firmware that
   actually reorders writes to the same block
 * Fixed a race between disconnect and receive_state, that could cause
   a IO lockup
 * Fixed resend/resubmit for requests with disk or network timeout
 * Make sure that hard state changed do not disturb the connection
   establishing process (I.e. detach due to an IO error). When the
   bug was triggered it caused a retry in the connect process
 * Postpone soft state changes to no disturb the connection
   establishing process (I.e. becoming primary). When the bug
   was triggered it could cause both nodes going into SyncSource state
 * Fixed a refcount leak that could cause failures when trying to
   unload a protocol family modules, that was used by DRBD
 * Dedicated page pool for meta data IOs
 * Deny normal detach (as opposed to --forced) if the user tries
   to detach from the last UpToDate disk in the resource
 * Fixed a possible protocol error that could be caused by
   "unusual" BIOs.
 * Enforce the disk-timeout option also on meta-data IO operations
 * Implemented stable bitmap pages when we do a full write out of
   the bitmap
 * Fixed a rare compatibility issue with DRBD's older than 8.3.7
   when negotiating the bio_size
 * Fixed a rare race condition where an empty resync could stall with
   if pause/unpause events happen in parallel
 * Made the re-establishing of connections quicker, if it got a broken pipe
   once. Previously there was a bug in the code caused it to waste the first
   successful established connection after a broken pipe event.

PS: I am postponing the drbd-8.4 for mainline for one or two kernel
    development cycles more (the ~400 patchets set).

1 files changed, 25 insertions, 6 deletions

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 4d3e6f6213b..620c70ff223 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -70,11 +70,29 @@ rwlock_t global_state_lock;
 void drbd_md_io_complete(struct bio *bio, int error)
 {
 	struct drbd_md_io *md_io;
+	struct drbd_conf *mdev;
 
 	md_io = (struct drbd_md_io *)bio->bi_private;
+	mdev = container_of(md_io, struct drbd_conf, md_io);
+
 	md_io->error = error;
 
-	complete(&md_io->event);
+	/* We grabbed an extra reference in _drbd_md_sync_page_io() to be able
+	 * to timeout on the lower level device, and eventually detach from it.
+	 * If this io completion runs after that timeout expired, this
+	 * drbd_md_put_buffer() may allow us to finally try and re-attach.
+	 * During normal operation, this only puts that extra reference
+	 * down to 1 again.
+	 * Make sure we first drop the reference, and only then signal
+	 * completion, or we may (in drbd_al_read_log()) cycle so fast into the
+	 * next drbd_md_sync_page_io(), that we trigger the
+	 * ASSERT(atomic_read(&mdev->md_io_in_use) == 1) there.
+	 */
+	drbd_md_put_buffer(mdev);
+	md_io->done = 1;
+	wake_up(&mdev->misc_wait);
+	bio_put(bio);
+	put_ldev(mdev);
 }
 
 /* reads on behalf of the partner,
@@ -226,6 +244,7 @@ void drbd_endio_pri(struct bio *bio, int error)
 	spin_lock_irqsave(&mdev->req_lock, flags);
 	__req_mod(req, what, &m);
 	spin_unlock_irqrestore(&mdev->req_lock, flags);
+	put_ldev(mdev);
 
 	if (m.bio)
 		complete_master_bio(mdev, &m);
@@ -290,7 +309,7 @@ void drbd_csum_bio(struct drbd_conf *mdev, struct crypto_hash *tfm, struct bio *
 	sg_init_table(&sg, 1);
 	crypto_hash_init(&desc);
 
-	__bio_for_each_segment(bvec, bio, i, 0) {
+	bio_for_each_segment(bvec, bio, i) {
 		sg_set_page(&sg, bvec->bv_page, bvec->bv_len, bvec->bv_offset);
 		crypto_hash_update(&desc, &sg, sg.length);
 	}
@@ -728,7 +747,7 @@ int w_start_resync(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
 	}
 
 	drbd_start_resync(mdev, C_SYNC_SOURCE);
-	clear_bit(AHEAD_TO_SYNC_SOURCE, &mdev->current_epoch->flags);
+	clear_bit(AHEAD_TO_SYNC_SOURCE, &mdev->flags);
 	return 1;
 }
 
@@ -1519,14 +1538,14 @@ void drbd_start_resync(struct drbd_conf *mdev, enum drbd_conns side)
 	}
 
 	drbd_state_lock(mdev);
-
+	write_lock_irq(&global_state_lock);
 	if (!get_ldev_if_state(mdev, D_NEGOTIATING)) {
+		write_unlock_irq(&global_state_lock);
 		drbd_state_unlock(mdev);
 		return;
 	}
 
-	write_lock_irq(&global_state_lock);
-	ns = mdev->state;
+	ns.i = mdev->state.i;
 
 	ns.aftr_isp = !_drbd_may_sync_now(mdev);