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Commit 8eb0dfdb authored by Adam Borowski's avatar Adam Borowski Committed by David Sterba
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btrfs: fix int32 overflow in shrink_delalloc(). 



UBSAN: Undefined behaviour in fs/btrfs/extent-tree.c:4623:21
signed integer overflow:
10808 * 262144 cannot be represented in type 'int [8]'

If 8192<=items<16384, we request a writeback of an insane number of pages
which is benign (everything will be written).  But if items>=16384, the
space reservation won't be enough.

Signed-off-by: default avatarAdam Borowski <kilobyte@angband.pl>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 2f3165ec

fs/btrfs/extent-tree.c

+1 −1
Original line number Diff line number Diff line
@@ -4620,7 +4620,7 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig, 


	/* Calc the number of the pages we need flush for space reservation */

	items = calc_reclaim_items_nr(root, to_reclaim);

	to_reclaim = items * EXTENT_SIZE_PER_ITEM;

	to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;



	trans = (struct btrfs_trans_handle *)current->journal_info;

	block_rsv = &root->fs_info->delalloc_block_rsv;