On Thu, May 13, 2010 at 11:52:47AM -0400, Daniel P. Berrange wrote:
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.
Patch looks fine to me overall
+ + +#ifdef __linux__ + +#ifndef OCFS2_SUPER_MAGIC +#define OCFS2_SUPER_MAGIC 0x7461636f +#endif +#ifndef GFS2_MAGIC +#define GFS2_MAGIC 0x01161970 +#endif +#ifndef AFS_FS_MAGIC +#define AFS_FS_MAGIC 0x6B414653 +#endif
hum, cppi is gonna complain on make syntax-check there
+ +int virStorageFileIsSharedFS(const char *path) +{ + struct statfs sb; + + if (statfs(path, &sb) < 0) { + virReportSystemError(errno, + _("cannot determine filesystem for '%s'"), + path); + return -1; + } + + VIR_DEBUG("Check if path %s with FS magic %lld is shared", + path, (long long int)sb.f_type); + + if (sb.f_type == NFS_SUPER_MAGIC || + sb.f_type == GFS2_MAGIC || + sb.f_type == OCFS2_SUPER_MAGIC || + sb.f_type == AFS_FS_MAGIC) { + return 1; + } + + return 0; +} +#else +int virStorageFileIsSharedFS(const char *path ATTRIBUTE_UNUSED) +{ + /* XXX implement me :-) */ + return 0; +} +#endif
I wonder if we shouldn't try to unify with the existing NFS lookup done in qemu_driver.c where we have this kind of NFS_SUPER_MAGIC It would be good to have all those filesystem specific checks cleanly exported from util Like also isolating the routine to find the fstype of a file/directory currently in the middle of qemudDomainSaveFlag() But the cleanup is not urgent, ACK once the cppi is fixed, Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/