Try this: create a 2GB file A in a subvolume vol_0 take a snapshot snap_1 of vol_0 Now see if their shared disk blocks give rise to shared VM resource: dd if=vol_0/A of=/dev/null dd if=snap_1/A of=/dev/null And you will discover that the 2 dd sessions take same amount of time to complete, vmstat will show that they incurred same amount of disk IO. Now shouldn't vfs/vm be smart enough to know that they are identical disk blocks and save the disk IOs? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
