[PATCH] FIX: Cannot continue reshape if incremental assembly is used

[Lukasz Dorau <lukasz.dorau@intel.com>]

Description of the bug:
Interrupted reshape cannot be continued using incremental assembly.
Array becomes inactive.

Cause of the bug:
Reshape tried to continue with insufficient number of disks
added by incremental assembly (tested using capacity expansion).

Solution:
During reshape adding disks to array should be blocked until
minimum required number of disks is ready to be added.

Signed-off-by: Lukasz Dorau <lukasz.dorau@intel.com>
---
 Assemble.c |   39 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/Assemble.c b/Assemble.c
index 25cfec1..da43162 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -1531,6 +1531,45 @@ int assemble_container_content(struct supertype *st, int mdfd,
 
 	if (sra)
 		sysfs_free(sra);
+	if (content->reshape_active) {
+		int disks_counter = 0;
+		int required_disks;
+		required_disks = content->array.raid_disks;
+		/* check if disks are removed */
+		if (content->delta_disks < 0)
+			required_disks += content->delta_disks;
+		/* Count devices available for assemblation.
+		*  In case of incremental assemblation during reshape
+		*  allow to add disks only if required minimum number of disks
+		*  is already collected to avoid assemblation problem.
+		*  */
+		for (dev = content->devs; dev; dev = dev->next) {
+			if (dev->disk.raid_disk >= 0)
+				disks_counter++;
+		}
+		/* allow for degradation */
+		switch (content->array.level) {
+		case 6:
+			required_disks--;
+		case 4:
+		case 5:
+			required_disks--;
+		default:
+			break;
+		}
+		/* check now, if number of disks allows for assemblation
+		*               */
+		if (disks_counter < required_disks) {
+			if (verbose >= 0)
+				fprintf(stderr, Name
+						": %s not assembled with %d devices "
+						"(required disks for assemblation: %i).\n",
+						chosen_name, disks_counter,
+						required_disks);
+			return 1;
+		}
+		block_subarray(content);
+	}
 	old_raid_disks = content->array.raid_disks - content->delta_disks;
 	for (dev = content->devs; dev; dev = dev->next)
 		if (sysfs_add_disk(content, dev, 1) == 0) {

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