summaryrefslogtreecommitdiffstats
path: root/include/block
diff options
context:
space:
mode:
authorAlberto Garcia2020-07-10 18:13:12 +0200
committerMax Reitz2020-08-25 08:33:20 +0200
commit40dee94320c9d76a656bd799870f9a81cf520b60 (patch)
tree6eb8eba58b0cd704d417d7e69d0bd15b0614c2ab /include/block
parentqcow2: Add subcluster support to qcow2_measure() (diff)
downloadqemu-40dee94320c9d76a656bd799870f9a81cf520b60.tar.gz
qemu-40dee94320c9d76a656bd799870f9a81cf520b60.tar.xz
qemu-40dee94320c9d76a656bd799870f9a81cf520b60.zip
qcow2: Add prealloc field to QCowL2Meta
This field allows us to indicate that the L2 metadata update does not come from a write request with actual data but from a preallocation request. For traditional images this does not make any difference, but for images with extended L2 entries this means that the clusters are allocated normally in the L2 table but individual subclusters are marked as unallocated. This will allow preallocating images that have a backing file. There is one special case: when we resize an existing image we can also request that the new clusters are preallocated. If the image already had a backing file then we have to hide any possible stale data and zero out the new clusters (see commit 955c7d6687 for more details). In this case the subclusters cannot be left as unallocated so the L2 bitmap must be updated. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <960d4c444a4f5a870e2b47e5da322a73cd9a2f5a.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'include/block')
0 files changed, 0 insertions, 0 deletions