From 8c50eedf03d8e62acd387b9aa9369dadcea9324c Mon Sep 17 00:00:00 2001

From: Peter Lieven <pl@kamp.de>

Date: Thu, 13 Jan 2022 15:44:26 +0100

Subject: [PATCH 6/6] block/rbd: workaround for ceph issue #53784

RH-Author: Stefano Garzarella <sgarzare@redhat.com>

RH-MergeRequest: 110: block/rbd: fix handling of holes in .bdrv_co_block_status

RH-Commit: [2/2] 1384557462e89bb539d0d25a1a471ad738fb9e89

RH-Bugzilla: 2037135

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

RH-Acked-by: Hanna Reitz <hreitz@redhat.com>

librbd had a bug until early 2022 that affected all versions of ceph that

supported fast-diff. This bug results in reporting of incorrect offsets

if the offset parameter to rbd_diff_iterate2 is not object aligned.

This patch works around this bug for pre Quincy versions of librbd.

Fixes: 0347a8fd4c3faaedf119be04c197804be40a384b

Cc: qemu-stable@nongnu.org

Signed-off-by: Peter Lieven <pl@kamp.de>

Message-Id: <20220113144426.4036493-3-pl@kamp.de>

Reviewed-by: Ilya Dryomov <idryomov@gmail.com>

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Tested-by: Stefano Garzarella <sgarzare@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit fc176116cdea816ceb8dd969080b2b95f58edbc0)

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

---

 block/rbd.c | 42 ++++++++++++++++++++++++++++++++++++++++--

 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/block/rbd.c b/block/rbd.c

index 20bb896c4a..8f183eba2a 100644

--- a/block/rbd.c

+++ b/block/rbd.c

@@ -1320,6 +1320,7 @@ static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,

     int status, r;

     RBDDiffIterateReq req = { .offs = offset };

     uint64_t features, flags;

+    uint64_t head = 0;

     assert(offset + bytes <= s->image_size);

@@ -1347,7 +1348,43 @@ static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,

         return status;

     }

-    r = rbd_diff_iterate2(s->image, NULL, offset, bytes, true, true,

+#if LIBRBD_VERSION_CODE < LIBRBD_VERSION(1, 17, 0)

+    /*

+     * librbd had a bug until early 2022 that affected all versions of ceph that

+     * supported fast-diff. This bug results in reporting of incorrect offsets

+     * if the offset parameter to rbd_diff_iterate2 is not object aligned.

+     * Work around this bug by rounding down the offset to object boundaries.

+     * This is OK because we call rbd_diff_iterate2 with whole_object = true.

+     * However, this workaround only works for non cloned images with default

+     * striping.

+     *

+     * See: https://tracker.ceph.com/issues/53784

+     */

+

+    /* check if RBD image has non-default striping enabled */

+    if (features & RBD_FEATURE_STRIPINGV2) {

+        return status;

+    }

+

+#pragma GCC diagnostic push

+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"

+    /*

+     * check if RBD image is a clone (= has a parent).

+     *

+     * rbd_get_parent_info is deprecated from Nautilus onwards, but the

+     * replacement rbd_get_parent is not present in Luminous and Mimic.

+     */

+    if (rbd_get_parent_info(s->image, NULL, 0, NULL, 0, NULL, 0) != -ENOENT) {

+        return status;

+    }

+#pragma GCC diagnostic pop

+

+    head = req.offs & (s->object_size - 1);

+    req.offs -= head;

+    bytes += head;

+#endif

+

+    r = rbd_diff_iterate2(s->image, NULL, req.offs, bytes, true, true,

                           qemu_rbd_diff_iterate_cb, &req;;

     if (r < 0 && r != QEMU_RBD_EXIT_DIFF_ITERATE2) {

         return status;

@@ -1366,7 +1403,8 @@ static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,

         status = BDRV_BLOCK_ZERO | BDRV_BLOCK_OFFSET_VALID;

     }

-    *pnum = req.bytes;

+    assert(req.bytes > head);

+    *pnum = req.bytes - head;

     return status;

 }

-- 

2.27.0