Btrfs: Fix add_extent_mapping to check for duplicates across the whole range
add_extent_mapping was allowing the insertion of overlapping extents.
This never used to happen because it only inserted the extents from disk
and those were never overlapping.
But, with the data=ordered code, the disk and memory representations of the
file are not the same. add_extent_mapping needs to ensure a new extent
does not overlap before it inserts.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 954b047..78ced11 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -207,7 +207,14 @@
int ret = 0;
struct extent_map *merge = NULL;
struct rb_node *rb;
+ struct extent_map *exist;
+ exist = lookup_extent_mapping(tree, em->start, em->len);
+ if (exist) {
+ free_extent_map(exist);
+ ret = -EEXIST;
+ goto out;
+ }
assert_spin_locked(&tree->lock);
rb = tree_insert(&tree->map, em->start, &em->rb_node);
if (rb) {