This patch makes two corrections to the newly-added QED support patch series:
- Correct the QED header field offsets
- Remove XML parsing for VIR_STORAGE_FILE_AUTO_SAFE
Signed-off-by: Adam Litke <agl@us.ibm.com>
Add an entry in fileTypeInfo for QED image files.
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Stefan Hajnoczi <stefan.hajnoczi@uk.ibm.com>
Cc: Anthony Liguori <aliguori@linux.vnet.ibm.com>
I am trying to use a qcow image with libvirt where the backing 'file' is a
qemu-nbd server. Unfortunately virDomainDiskDefForeachPath() assumes that
backingStore is always a real file so something like 'nbd:0:3333' is rejected
because a file with that name cannot be accessed. Note that I am not worried
about directly using nbd images. That would require a new disk type with XML
markup, etc. I only want it to be permitted as a backingStore
The following patch implements danpb's suggestion:
> I think I'm inclined to push the logic for skipping NBD one stage higher.
> I'd rather expect virStorageFileGetMetadata() to return all backing
> stores, even if not files. The virDomainDiskDefForeachPath() method
> should definitely ignore non-file backing stores though.
>
> So what I'm thinking is to extend the virStorageFileMetadata struct and
> just add a 'bool isFile' field to it. Default this field to true, unless
> you see the prefix of nbd: in which case set it to false. The
> virDomainDiskDefForeachPath() method can then skip over any backing
> store with isFile == false
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Daniel P. Berrange <berrange@redhat.com>
NFS does not support file labelling, so ignore this error
for stdin_path when on NFS.
* src/security/security_selinux.c: Ignore failures on labelling
stdin_path on NFS
* src/util/storage_file.c, src/util/storage_file.h: Refine
virStorageFileIsSharedFS() to allow it to check for a
specific FS type.
Require the disk image to be passed into virStorageFileGetMetadata.
If this is set to VIR_STORAGE_FILE_AUTO, then the format will be
resolved using probing. This makes it easier to control when
probing will be used
* src/qemu/qemu_driver.c, src/qemu/qemu_security_dac.c,
src/security/security_selinux.c, src/security/virt-aa-helper.c:
Set VIR_STORAGE_FILE_AUTO when calling virStorageFileGetMetadata.
* src/storage/storage_backend_fs.c: Probe for disk format before
calling virStorageFileGetMetadata.
* src/util/storage_file.h, src/util/storage_file.c: Remove format
from virStorageFileMeta struct & require it to be passed into
method.
The virStorageFileGetMetadataFromFD did two jobs in one. First
it probed for storage type, then it extracted metadata for the
type. It is desirable to be able to separate these jobs, allowing
probing without querying metadata, and querying metadata without
probing.
To prepare for this, split out probing code into a new pair of
methods
virStorageFileProbeFormatFromFD
virStorageFileProbeFormat
* src/util/storage_file.c, src/util/storage_file.h,
src/libvirt_private.syms: Introduce virStorageFileProbeFormat
and virStorageFileProbeFormatFromFD
When QEMU opens a backing store for a QCow2 file, it will
normally auto-probe for the format of the backing store,
rather than assuming it has the same format as the referencing
file. There is a QCow2 extension that allows an explicit format
for the backing store to be embedded in the referencing file.
This closes the auto-probing security hole in QEMU.
This backing store format can be useful for libvirt users
of virStorageFileGetMetadata, so extract this data and report
it.
QEMU does not require disk image backing store files to be in
the same format the file linkee. It will auto-probe the disk
format for the backing store when opening it. If the backing
store was intended to be a raw file this could be a security
hole, because a guest may have written data into its disk that
then makes the backing store look like a qcow2 file. If it can
trick QEMU into thinking the raw file is a qcow2 file, it can
access arbitrary files on the host by adding further backing
store links.
To address this, callers of virStorageFileGetMeta need to be
told of the backing store format. If no format is declared,
they can make a decision whether to allow format probing or
not.
When QEMU runs with its disk on NFS, and as a non-root user, the
disk is chownd to that non-root user. When migration completes
the last step is shutting down the QEMU on the source host. THis
normally resets user/group/security label. This is bad when the
VM was just migrated because the file is still in use on the dest
host. It is thus neccessary to skip the reset step for any files
found to be on a shared filesystem
* src/libvirt_private.syms: Export virStorageFileIsSharedFS
* src/util/storage_file.c, src/util/storage_file.h: Add a new
method virStorageFileIsSharedFS() to determine if a file is
on a shared filesystem (NFS, GFS, OCFS2, etc)
* src/qemu/qemu_driver.c: Tell security driver not to reset
disk labels on migration completion
* src/qemu/qemu_security_dac.c, src/qemu/qemu_security_stacked.c,
src/security/security_selinux.c, src/security/security_driver.h,
src/security/security_apparmor.c: Add ability to skip disk
restore step for files on shared filesystems.
Finally, we get to the point of all this.
Move virStorageGetMetadataFromFD() to virStorageFileGetMetadataFromFD()
and move to src/util/storage_file.[ch]
There's no functional changes in this patch, just code movement
* src/storage/storage_backend_fs.c: move code from here ...
* src/util/storage_file.[ch]: ... to here
* src/libvirt_private.syms: export virStorageFileGetMetadataFromFD()
Introduce a metadata structure and make virStorageGetMetadataFromFD()
fill it in.
* src/util/storage_file.h: add virStorageFileMetadata
* src/backend/storage_backend_fs.c: virStorageGetMetadataFromFD() now
fills in the virStorageFileMetadata structure
Rename virStorageVolFormatFileSystem to virStorageFileFormat and
move to src/util/storage_file.[ch]
* src/Makefile.am: add src/util/storage_file.[ch]
* src/conf/storage_conf.[ch]: move enum from here ...
* src/util/storage_file.[ch]: .. to here
* src/libvirt_private.syms: update To/FromString exports
* src/storage/storage_backend.c, src/storage/storage_backend_fs.c,
src/vbox/vbox_tmpl.c: update for above changes
