[BUG]
Since commit d729048be6 ("btrfs-progs: stop using
btrfs_root_item_v0"), "btrfs subvolume list -u" not longer correctly
reports UUID nor timestamp, while older (btrfs-progs v6.0.2) still works
correctly:
v6.0.2:
# btrfs subv list -u /mnt/btrfs/
ID 256 gen 12 top level 5 uuid ed4af580-d512-2644-b392-2a71aaeeb99e path subv1
ID 257 gen 13 top level 5 uuid a22ccba7-0a0a-a94f-af4b-5116ab58bb61 path subv2
v6.1:
# ./btrfs subv list -u /mnt/btrfs/
ID 256 gen 12 top level 5 uuid - path subv1
ID 257 gen 13 top level 5 uuid - path subv2
[CAUSE]
Commit d729048be6 ("btrfs-progs: stop using btrfs_root_item_v0")
removed old btrfs_root_item_v0, but incorrectly changed the check for
v0 root item.
Now we will treat v0 root items as latest root items, causing possible
out-of-bound access, while treating current root items as older v0 root
items, ignoring the UUID nor timestamp.
[FIX]
Fix the bug by using correct checks, and add extra comments on the
branches.
Issue: #562
Fixes: d729048be6 ("btrfs-progs: stop using btrfs_root_item_v0")
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
b7e3acd615