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[Qemu-devel] [PULL 13/62] docs: Make the recommendation for the backing
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PULL 13/62] docs: Make the recommendation for the backing file name position a requirement |
Date: |
Fri, 8 Aug 2014 19:39:14 +0200 |
From: Maria Kustova <address@hidden>
The current version of the qcow2 specification recommends to save the backing
file name in the end of the first cluster. It follows that the backing file
name can be saved somewhere in the image, but the first cluster, which
contradicts the current QEMU implementation.
The patch makes the backing file name required to be placed after the header
extensions in the first image cluster.
Signed-off-by: Maria Kustova <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
docs/specs/qcow2.txt | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index 3f713a6..cfbc8b0 100644
--- a/docs/specs/qcow2.txt
+++ b/docs/specs/qcow2.txt
@@ -135,12 +135,12 @@ be stored. Each extension has a structure like the
following:
Unless stated otherwise, each header extension type shall appear at most once
in the same image.
-The remaining space between the end of the header extension area and the end of
-the first cluster can be used for the backing file name. It is not allowed to
-store other data here, so that an implementation can safely modify the header
-and add extensions without harming data of compatible features that it
-doesn't support. Compatible features that need space for additional data can
-use a header extension.
+If the image has a backing file then the backing file name should be stored in
+the remaining space between the end of the header extension area and the end of
+the first cluster. It is not allowed to store other data here, so that an
+implementation can safely modify the header and add extensions without harming
+data of compatible features that it doesn't support. Compatible features that
+need space for additional data can use a header extension.
== Feature name table ==
--
1.8.3.1
- [Qemu-devel] [PULL 06/62] block: Use bdrv_nb_sectors() in bdrv_aligned_preadv(), (continued)
- [Qemu-devel] [PULL 06/62] block: Use bdrv_nb_sectors() in bdrv_aligned_preadv(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 03/62] nbd: Follow the BDS' AIO context, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 07/62] block: Use bdrv_nb_sectors() in bdrv_co_get_block_status(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 08/62] block: Use bdrv_nb_sectors() in img_convert(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 09/62] block: Use bdrv_nb_sectors() where sectors, not bytes are wanted, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 10/62] block: Drop superfluous aligning of bdrv_getlength()'s value, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 11/62] qemu-img: Make img_convert() get image size just once per image, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 12/62] block: Avoid bdrv_get_geometry() where errors should be detected, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 14/62] configure: explicitly state version requirements to devel packages, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 15/62] xen_disk: fix possible null-ptr dereference, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 13/62] docs: Make the recommendation for the backing file name position a requirement,
Kevin Wolf <=
- [Qemu-devel] [PULL 16/62] docs/multiple-iothreads.txt: add documentation on IOThread programming, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 18/62] qdev-monitor: include QOM properties in -device FOO, help output, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 17/62] qmp: hide "hotplugged" device property from device-list-properties, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 19/62] qemu-iotests: Add data pattern in version3 VMDK sample image in 059, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 21/62] qemu-img info: show nocow info, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 20/62] vmdk: Optimize cluster allocation, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 24/62] block/archipelago: Add support for creating images, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 23/62] block/archipelago: Implement bdrv_parse_filename(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 25/62] QMP: Add support for Archipelago, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 22/62] block: Support Archipelago as a QEMU block backend, Kevin Wolf, 2014/08/08