[ Upstream commit 54df8b80cc ]
[BUG]
When a scrub failed immediately without any byte scrubbed, the returned
btrfs_scrub_progress::last_physical will always be 0, even if there is a
non-zero @start passed into btrfs_scrub_dev() for resume cases.
This will reset the progress and make later scrub resume start from the
beginning.
[CAUSE]
The function btrfs_scrub_dev() accepts a @progress parameter to copy its
updated progress to the caller, there are cases where we either don't
touch progress::last_physical at all or copy 0 into last_physical:
- last_physical not updated at all
If some error happened before scrubbing any super block or chunk, we
will not copy the progress, leaving the @last_physical untouched.
E.g. failed to allocate @sctx, scrubbing a missing device or even
there is already a running scrub and so on.
All those cases won't touch @progress at all, resulting the
last_physical untouched and will be left as 0 for most cases.
- Error out before scrubbing any bytes
In those case we allocated @sctx, and sctx->stat.last_physical is all
zero (initialized by kvzalloc()).
Unfortunately some critical errors happened during
scrub_enumerate_chunks() or scrub_supers() before any stripe is really
scrubbed.
In that case although we will copy sctx->stat back to @progress, since
no byte is really scrubbed, last_physical will be overwritten to 0.
[FIX]
Make sure the parameter @progress always has its @last_physical member
updated to @start parameter inside btrfs_scrub_dev().
At the very beginning of the function, set @progress->last_physical to
@start, so that even if we error out without doing progress copying,
last_physical is still at @start.
Then after we got @sctx allocated, set sctx->stat.last_physical to
@start, this will make sure even if we didn't get any byte scrubbed, at
the progress copying stage the @last_physical is not left as zero.
This should resolve the resume progress reset problem.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Qu WenruoandGreg Kroah-Hartman
ca91db4f89