Operational Defect Database

BugZero found this defect 435 days ago.

Veeam | kb4428

Veeam Agent for Linux 6 blksnap module - Xen PV/PVHVM filesystem corruption

Last update date:


Affected products:

Veeam Agent for Linux

Affected releases:


Fixed releases:

No fixed releases provided.



After Veeam Agent for Linux completes a volume-level backup or file-level backup using a snapshot, filesystem corruption is detected. /var/log/syslog example: EXT4-fs error (device dm-0): ext4_lookup:1752: inode #129793: comm ls: iget: checksum invalid EXT4-fs error (device dm-0): ext4_lookup:1752: inode #129793: comm ls: iget: checksum invalid EXT4-fs warning (device dm-0): ext4_dirblock_csum_verify:400: inode #12: comm ls: No space for directory leaf checksum. Please run e2fsck -D. EXT4-fs error (device dm-0): htree_dirblock_to_tree:1042: inode #12: comm ls: Directory block failed checksum   Affected Configuration Veeam Agent for Linux 6 is installed on a Xen PV/PVHVM virtual machine running a Linux distribution that uses blksnap kernel module by default (RHEL/Oracle Linux 9, SLES 15 SP3+,openSUSE Tumbleweed/Leap 15.3+,Ubuntu 22.04+, or Debian 11). For more information about which distributions use blksnap, refer to KB2804.


Research has determined that this issue is related xen-blkfront handling of read requests with the REQ_FUA bit enabled (implicitly converting these read requests to be zero-write requests, effectively zeroing the block being read). For more information, refer to this Xenproject patch request: [PATCH] xen/blkfront: Only check REQ_FUA for writes


This issue is resolved in Veeam Agent for Linux To obtain it, contact Veeam Technical Support.

More Information

Veeam Agent for Linux User Guide — System Requirements For virtual machines, only full virtualization type is supported. Oracle VM virtual machines are supported with limitations. Virtual I/O (VirtIO) devices have experimental support status. Other containers and paravirtualized instances are not supported and may result in corruption of the source file system — for more information, see this Veeam KB article.

Additional Resources / Links


BugZero® Risk Score

What's this?

Coming soon



Learn More