From 539f358a30d5113bad81c41a2e7ba8770d6c9f6e Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Mon, 7 Oct 2013 13:42:57 +0300 Subject: [PATCH] Btrfs: fix the dev-replace suspend sequence Replace progresses strictly from lower to higher offsets, and the progress is tracked in chunks, by storing the physical offset of the dev_extent which is being copied in the cursor_left field of btrfs_dev_replace_item. When we are done copying the chunk, left_cursor is updated to point one byte past the dev_extent, so that on resume we can skip the dev_extents that have already been copied. There is a major bug (which goes all the way back to the inception of dev-replace in 3.8) in the way left_cursor is bumped: the bump is done unconditionally, without any regard to the scrub_chunk return value. On suspend (and also on any kind of error) scrub_chunk returns early, i.e. without completing the copy. This leads to us skipping the chunk that hasn't been fully copied yet when resuming. Fix this by doing the cursor_left update only if scrub_chunk ret is 0. (On suspend scrub_chunk returns with -ECANCELED, so this fix covers both suspend and error cases.) Cc: Stefan Behrens Signed-off-by: Ilya Dryomov Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- Reading git-format-patch failed