diff mbox series

[38/79] blkdebug: Sanity check block layer guarantees

Message ID 1503965694-10794-39-git-send-email-mdroth@linux.vnet.ibm.com
State New
Headers show
Series Patch Round-up for stable 2.9.1, freeze on 2017-09-04 | expand

Commit Message

Michael Roth Aug. 29, 2017, 12:14 a.m. UTC 
From: Eric Blake <eblake@redhat.com>

Commits 04ed95f4 and 1a62d0ac updated the block layer to auto-fragment
any I/O to fit within device boundaries. Additionally, when using a
minimum alignment of 4k, we want to ensure the block layer does proper
read-modify-write rather than requesting I/O on a slice of a sector.
Let's enforce that the contract is obeyed when using blkdebug.  For
now, blkdebug only allows alignment overrides, and just inherits other
limits from whatever device it is wrapping, but a future patch will
further enhance things.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170429191419.30051-5-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit e0ef439588ce1ede747f82b77d893190c1cc9f4d)
* prereq for 81c219a
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 block/blkdebug.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
diff mbox series

Patch

diff --git a/block/blkdebug.c b/block/blkdebug.c
index 46bd08a..b2cee0c 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -429,6 +429,13 @@  blkdebug_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
     BDRVBlkdebugState *s = bs->opaque;
     BlkdebugRule *rule = NULL;
 
+    /* Sanity check block layer guarantees */
+    assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
+    assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
+    if (bs->bl.max_transfer) {
+        assert(bytes <= bs->bl.max_transfer);
+    }
+
     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
         uint64_t inject_offset = rule->options.inject.offset;
 
@@ -453,6 +460,13 @@  blkdebug_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
     BDRVBlkdebugState *s = bs->opaque;
     BlkdebugRule *rule = NULL;
 
+    /* Sanity check block layer guarantees */
+    assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
+    assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
+    if (bs->bl.max_transfer) {
+        assert(bytes <= bs->bl.max_transfer);
+    }
+
     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
         uint64_t inject_offset = rule->options.inject.offset;