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authorAdam Borowski <kilobyte@angband.pl>2016-05-08 15:08:00 +0200
committerDavid Sterba <dsterba@suse.com>2016-05-09 11:51:19 +0200
commit8eb0dfdbda3f56bf7d248ed87fcc383df114ecbb (patch)
tree94790c517b62412cf192002fbf2a454db3742472
parent2f3165ecf103599f82bf0ea254039db335fb5005 (diff)
downloadlinux-8eb0dfdbda3f56bf7d248ed87fcc383df114ecbb.tar.gz
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: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/extent-tree.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 84e060eb0de8..391f576789e9 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -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;