[PATCH 2/2] blkdiscard: fail on sector misalignment

[Federico Simoncelli <fsimonce@redhat.com>]

---
 sys-utils/blkdiscard.c            | 10 +++++++---
 tests/expected/blkdiscard/offsets | 12 ++++++------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/sys-utils/blkdiscard.c b/sys-utils/blkdiscard.c
index 1eb2b285..76c72b8 100644
--- a/sys-utils/blkdiscard.c
+++ b/sys-utils/blkdiscard.c
@@ -144,9 +144,9 @@ int main(int argc, char **argv)
 	if (ioctl(fd, BLKSSZGET, &secsize))
 		err(EXIT_FAILURE, _("%s: BLKSSZGET ioctl failed"), path);
 
-	/* align range to the sector size */
-	range[0] = (range[0] + secsize - 1) & ~(secsize - 1);
-	range[1] &= ~(secsize - 1);
+	/* check offset alignment to the sector size */
+	if (range[0] % secsize)
+		errx(EXIT_FAILURE, _("%s: offset %" PRIu64 " is not aligned"), path, range[0]);
 
 	/* is the range end behind the end of the device ?*/
 	if (range[0] > blksize)
@@ -155,6 +155,10 @@ int main(int argc, char **argv)
 	if (end < range[0] || end > blksize)
 		range[1] = blksize - range[0];
 
+	/* check length alignment to the sector size */
+	if (range[1] % secsize)
+		errx(EXIT_FAILURE, _("%s: length %" PRIu64 " is not aligned"), path, range[1]);
+
 	if (secure) {
 		if (ioctl(fd, BLKSECDISCARD, &range))
 			err(EXIT_FAILURE, _("%s: BLKSECDISCARD ioctl failed"), path);
diff --git a/tests/expected/blkdiscard/offsets b/tests/expected/blkdiscard/offsets
index 766c39d..abedb08 100644
--- a/tests/expected/blkdiscard/offsets
+++ b/tests/expected/blkdiscard/offsets
@@ -1,16 +1,16 @@
 create loop device from image
 testing offsets with full block size
 Discarded 10485760 bytes from the offset 0
-Discarded 10485248 bytes from the offset 512
-Discarded 10485248 bytes from the offset 512
+blkdiscard: offset 1 is not aligned
+blkdiscard: offset 511 is not aligned
 Discarded 10485248 bytes from the offset 512
 Discarded 10484736 bytes from the offset 1024
 testing offsets with specific length
 Discarded 5242880 bytes from the offset 0
-Discarded 5242880 bytes from the offset 0
-Discarded 5242880 bytes from the offset 0
-Discarded 5242880 bytes from the offset 512
-Discarded 5242880 bytes from the offset 512
+blkdiscard: length 5242881 is not aligned
+blkdiscard: length 5243391 is not aligned
+blkdiscard: offset 1 is not aligned
+blkdiscard: offset 511 is not aligned
 Discarded 5242880 bytes from the offset 512
 Discarded 5242880 bytes from the offset 1024
 detach loop device from image
-- 
1.9.3