Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 24 Aug 2020 17:28:29 +0200 | From | David Sterba <> | Subject | Re: [PATCH v3] btrfs: block-group: Fix free-space bitmap threshould |
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On Fri, Aug 21, 2020 at 11:54:44AM -0300, Marcos Paulo de Souza wrote: > From: Marcos Paulo de Souza <mpdesouza@suse.com> > > [BUG] > After commit 9afc66498a0b ("btrfs: block-group: refactor how we read one > block group item"), cache->length is being assigned after calling > btrfs_create_block_group_cache. This causes a problem since > set_free_space_tree_thresholds is calculate the free-space threshould to > decide is the free-space tree should convert from extents to bitmaps. > > The current code calls set_free_space_tree_thresholds with cache->length > being 0, which then makes cache->bitmap_high_thresh being zero. This > implies the system will always use bitmap instead of extents, which is > not desired if the block group is not fragmented. > > This behavior can be seen by a test that expects to repair systems > with FREE_SPACE_EXTENT and FREE_SPACE_BITMAP, but the current code only > created FREE_SPACE_BITMAP. > > [FIX] > Call set_free_space_tree_thresholds after setting cache->length. There > is now a WARN_ON in set_free_space_tree_thresholds to help preventing > the same mistake to happen again in the future. > > Link: https://github.com/kdave/btrfs-progs/issues/251 > Fixes: 9afc66498a0b ("btrfs: block-group: refactor how we read one block group item") > CC: stable@vger.kernel.org # 5.8+ > Reviewed-by: Qu Wenruo <wqu@suse.com> > Reviewed-by: Filipe Manana <fdmanana@suse.com> > Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Added to misc-next, thanks.
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