This bug has been copied from bug #606651 and has been proposed to be backported to 5.5 z-stream (EUS).
Test with kvm-83-164.el5_5.19 by using "qemu-img check", different kind of errors have been disdinguished, so this bug has been fixed. # qemu-img check 16g ERROR refcount block 8191 is outside image Leaked cluster 16380 refcount=1 reference=0 Leaked cluster 16381 refcount=1 reference=0 Leaked cluster 16382 refcount=1 reference=0 Leaked cluster 16383 refcount=1 reference=0 Leaked cluster 16384 refcount=1 reference=0 Leaked cluster 16385 refcount=1 reference=0 Leaked cluster 16386 refcount=1 reference=0 Leaked cluster 16387 refcount=1 reference=0 Leaked cluster 180222 refcount=1 reference=0 Leaked cluster 180223 refcount=1 reference=0 Leaked cluster 180224 refcount=1 reference=0 Leaked cluster 180225 refcount=1 reference=0 Leaked cluster 180226 refcount=1 reference=0 Leaked cluster 180227 refcount=1 reference=0 Leaked cluster 180228 refcount=1 reference=0 Leaked cluster 180229 refcount=1 reference=0 Leaked cluster 245754 refcount=1 reference=0 Leaked cluster 245755 refcount=1 reference=0 Leaked cluster 245756 refcount=1 reference=0 Leaked cluster 245757 refcount=1 reference=0 Leaked cluster 245758 refcount=1 reference=0 Leaked cluster 245759 refcount=1 reference=0 1 errors were found on the image. Data may be corrupted, or further writes to the image may corrupt it. 22 leaked clusters were found on the image. This means waste of disk space, but no harm to data.
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: Using a thinly provisioned VirtIO disk on iSCSI storage and performing a "qemu-img" check during an "e_no_space" event returned cluster errors. With this update, the errors no longer appear.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2010-0627.html