Atomic Test And Set Of Disk Block Returned False For Equality Link May 2026

smartctl -a /dev/sdX cat /sys/block/sdX/stat sg_turs /dev/sdX On Linux with SCSI devices:

COMPARE_AND_WRITE command structure: - Compare data from disk block (starting at logical block address LBA) - Compare against data sent in the command buffer - If match, write new data to same LBA; if no match, return CHECK CONDITION - Sense data indicates: "COMPARE AND WRITE MISCOMPARE" The error message "atomic test and set of disk block returned false for equality" directly corresponds to the MISCOMPARE sense code (0x1D, qualifier 0x00). write new data to same LBA

sg_inq /dev/sdX sg_persist -i /dev/sdX # Show all registered initiators For Pacemaker/Corosync: if no match

while (atomic_test_and_set(disk_block, expected, new) == false) // Another node won the race current_leader = read_leader_from_disk(); if (current_leader == myself) // Possibly stale cache, re-read block invalidate_disk_cache(); else backoff_and_retry(); re-read block invalidate_disk_cache()

pcs status crm_verify -L -V pcs cluster cib | grep reservation Solution 1: Handle the Failure in Application Logic If the error is expected during leader election, implement proper handling:

uint32_t stored_crc = read_crc(block); uint32_t computed_crc = crc32(block_data); if (stored_crc != computed_crc) repair_block_from_replica();