Discard on zvols should not exceed the length of a block

37f9dac replaced the end-start calculation with a cached value, but neglected to update it on discard operations. This can cause us to discard data not requested, causing data loss on zvols. Reported-by: Richard Connon <[email protected]> Signed-off-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #3798
openzfs · Sep 19, 2015 · f52ebcb · f52ebcb
1 parent 7a27ad0
commit f52ebcb
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
@@ -662,6 +662,7 @@ zvol_discard(struct bio *bio)
 	if (!(bio->bi_rw & REQ_SECURE)) {
 		start = P2ROUNDUP(start, zv->zv_volblocksize);
 		end = P2ALIGN(end, zv->zv_volblocksize);
+		size = end - start;
 	}
 #endif