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[PULL,19/22] docs/interop/qcow2: Improve bitmap flag in_use specification

Message ID 20190312202337.5278-20-jsnow@redhat.com (mailing list archive)
State New, archived
Headers show
Series [PULL,01/22] block/dirty-bitmap: add recording and busy properties | expand

Commit Message

John Snow March 12, 2019, 8:23 p.m. UTC 
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

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metadata outdated, such as AUTO flag, which mirrors enabled/disabled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>
---
 docs/interop/qcow2.txt | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
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Patch

diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
index 8c3098d8d9..af5711e533 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+                         contents may be outdated.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