btrfs: fix ref-verify to catch operations on 0 ref extents
While debugging I noticed I wasn't getting ref verify errors before
everything blew up. Turns out it's because we don't warn when we try to
add a normal ref via btrfs_inc_ref() if the block entry exists but has 0
references. This is incorrect, we should never be doing anything other
than adding a new extent once a block entry drops to 0 references.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index 454a101..7887317 100644
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -803,6 +803,15 @@
kfree(ref);
kfree(ra);
goto out_unlock;
+ } else if (be->num_refs == 0) {
+ btrfs_err(fs_info,
+ "trying to do action %d for a bytenr that has 0 total references",
+ action);
+ dump_block_entry(fs_info, be);
+ dump_ref_action(fs_info, ra);
+ kfree(ref);
+ kfree(ra);
+ goto out_unlock;
}
if (!parent) {
