block: improve automatic native capacity unlocking

Currently, native capacity unlocking is initiated only when a
recognized partition extends beyond the end of the disk.  However,
there are several other unhandled cases where truncated capacity can
lead to misdetection of partitions.

* Partition table is fully beyond EOD.

* Partition table is partially beyond EOD (daisy chained ones).

* Recognized partition starts beyond EOD.

This patch updates generic partition check code such that all the
above three cases are handled too.  For the first two, @state tracks
whether low level partition check code tried to read beyond EOD during
partition scan and triggers native capacity unlocking accordingly.
The third is now handled similarly to the original unlocking case.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/partitions/check.h b/fs/partitions/check.h
index 4b31a97775be..52f8bd399396 100644
--- a/fs/partitions/check.h
+++ b/fs/partitions/check.h
@@ -15,11 +15,16 @@ struct parsed_partitions {
 	} parts[DISK_MAX_PARTS];
 	int next;
 	int limit;
+	bool access_beyond_eod;
 };
 
 static inline void *read_part_sector(struct parsed_partitions *state,
 				     sector_t n, Sector *p)
 {
+	if (n >= get_capacity(state->bdev->bd_disk)) {
+		state->access_beyond_eod = true;
+		return NULL;
+	}
 	return read_dev_sector(state->bdev, n, p);
 }