btrfs-progs-4.7.3-1.fc26.x86_64 I've been seeing this behavior for awhile (months, maybe a year) where 'list' generation does not match 'show' generation for a read only snapshot. All of the items in this list are read only snapshots, and the only one that has a valid list and show generation is the last one. The generation 8019 is from today, but these read only snapshots were created on their respective dates and have totally different generations. My expectation is that upon creating a read only snapshot, the gen for that subvolum should be set in stone and never change again. Show seems to agree, but list is coming up with something different. [chris@f24s first]$ sudo btrfs sub list -t /brick2 ID gen top level path -- --- --------- ---- 1208 8019 5 everything-20160218 1555 8019 5 everything-20160226 1558 8019 5 everything-20160304 1560 8019 5 everything-20160322 1567 8019 5 everything-20160405 1572 8019 5 everything-20160405-2 1573 8019 5 everything-20160409 1574 8019 5 everything-20160410 1592 8019 5 everything-20160416 1593 8019 5 everything-20160424 1600 8019 5 everything-20160504 1601 8019 5 everything-20160608 1607 8019 5 everything-20160711 1611 8019 5 everything-20160720 1614 8019 5 everything-20160805 1615 8019 5 everything-20160831 1617 8025 5 everything-20160913 1629 8028 5 everything-20160922 [chris@f24s first]$ sudo btrfs sub show everything-20160218 /mnt/first/everything-20160218 Name: everything-20160218 UUID: snip Parent UUID: snip Received UUID: - Creation time: 2016-02-18 21:24:03 -0700 Subvolume ID: 673 Generation: 1759 Gen at creation: 1007 Parent ID: 5 Top level ID: 5 Flags: readonly Snapshot(s):
Wrong path to the subvolume explains why 'list' and 'show' differ. They're the same. But question remains what's changing these read only snapshots' generation numbers, and whether it's expected. [root@f24s brick2]# btrfs sub show /brick2/everything-20160218/ /brick2/everything-20160218 Name: everything-20160218 UUID: snip Parent UUID: - Received UUID: snip Creation time: 2016-02-18 21:54:38 -0700 Subvolume ID: 1208 Generation: 8019 Gen at creation: 6533 Parent ID: 5 Top level ID: 5 Flags: readonly Snapshot(s): everything-20160226