Recently we had a scrub use-after-free caused by unaligned chunk
length, although the fix was submitted, we may want to do extra checks
for a chunk's alignment.
This patch adds such check for the starting bytenr and length of a
chunk, to make sure they are properly aligned to 64K stripe boundary.
By default, the check only leads to a warning but is not treated as an
error, as we expect kernel to handle such unalignment without any
problem.
But if the new debug environmental variable,
BTRFS_PROGS_DEBUG_STRICT_CHUNK_ALIGNMENT, is specified, then we will
treat it as an error. So that we can detect unexpected chunks from
btrfs-progs, and fix them before reaching the end users.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
6dfc69104b