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| author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2019-03-11 21:51:44 +0300 |
|---|---|---|
| committer | John Snow <jsnow@redhat.com> | 2019-03-12 12:06:11 -0400 |
| commit | 2fd490c614500fc669386eaf8710cd2d015f548e (patch) | |
| tree | 83c79782f6c2c12e2f02d55b809d621ee67d6336 | |
| parent | 796a3798ab882ae78a8203acd335ded4e10e3afb (diff) | |
| download | qemu-2fd490c614500fc669386eaf8710cd2d015f548e.zip qemu-2fd490c614500fc669386eaf8710cd2d015f548e.tar.gz qemu-2fd490c614500fc669386eaf8710cd2d015f548e.tar.bz2 | |
docs/interop/qcow2: Improve bitmap flag in_use specification
We already use (we didn't notice it) IN_USE flag for marking bitmap
metadata outdated, such as AUTO flag, which mirrors enabled/disabled
bitmaps. Now we are going to support bitmap resize, so it's good to
write IN_USE meaning with more details.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190311185147.52309-2-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
| -rw-r--r-- | docs/interop/qcow2.txt | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt index 8c3098d..af5711e 100644 --- a/docs/interop/qcow2.txt +++ b/docs/interop/qcow2.txt @@ -633,7 +633,10 @@ Structure of a bitmap directory entry: Bit 0: in_use The bitmap was not saved correctly and may be - inconsistent. + inconsistent. Although the bitmap metadata is still + well-formed from a qcow2 perspective, the metadata + (such as the auto flag or bitmap size) or data + contents may be outdated. 1: auto The bitmap must reflect all changes of the virtual @@ -761,8 +764,8 @@ corresponding range of the virtual disk (see above) was written to while the bitmap was 'enabled'. An unset bit means that this range was not written to. The software doesn't have to sync the bitmap in the image file with its -representation in RAM after each write. Flag 'in_use' should be set while the -bitmap is not synced. +representation in RAM after each write or metadata change. Flag 'in_use' +should be set while the bitmap is not synced. In the image file the 'enabled' state is reflected by the 'auto' flag. If this flag is set, the software must consider the bitmap as 'enabled' and start |