Btrfs: memset to avoid stale content in btree leaf
This is an additional patch to
"Btrfs: memset to avoid stale content in btree node block".
This uses memset to initialize the unused space in a leaf to avoid
potential stale content, which may be incurred by pushing items
between sibling leaves.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0d1876c..ee40384 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3725,8 +3725,10 @@
struct block_device *bdev = fs_info->fs_devices->latest_bdev;
struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
u64 offset = eb->start;
+ u32 nritems;
unsigned long i, num_pages;
unsigned long bio_flags = 0;
+ unsigned long start, end;
int write_flags = (epd->sync_io ? WRITE_SYNC : 0) | REQ_META;
int ret = 0;
@@ -3736,15 +3738,21 @@
if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
bio_flags = EXTENT_BIO_TREE_LOG;
- /* set btree node beyond nritems with 0 to avoid stale content */
+ /* set btree blocks beyond nritems with 0 to avoid stale content. */
+ nritems = btrfs_header_nritems(eb);
if (btrfs_header_level(eb) > 0) {
- u32 nritems;
- unsigned long end;
-
- nritems = btrfs_header_nritems(eb);
end = btrfs_node_key_ptr_offset(nritems);
memset_extent_buffer(eb, 0, end, eb->len - end);
+ } else {
+ /*
+ * leaf:
+ * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
+ */
+ start = btrfs_item_nr_offset(nritems);
+ end = btrfs_leaf_data(eb) +
+ leaf_data_end(fs_info->tree_root, eb);
+ memset_extent_buffer(eb, 0, start, end - start);
}
for (i = 0; i < num_pages; i++) {