Btrfs: fix off-by-one logic error in btrfs_realloc_node (5dfe2be7) · Commits · 戴 / test

The end_slot variable actually matches the number of pointers in the node and not the last slot (which is 'nritems - 1'). Therefore in order to check that the current slot in the for loop doesn't match the last one, the correct logic is to check if 'i' is less than 'end_slot - 1' and not 'end_slot - 2'. Fix this and set end_slot to be 'nritems - 1', as it's less confusing since the variable name implies it's inclusive rather then exclusive. Signed-off-by:

Filipe Manana <fdmanana@suse.com> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/ctree.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1645,14 +1645,14 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,

		parent_nritems = btrfs_header_nritems(parent);
		blocksize = root->nodesize;
		end_slot = parent_nritems;
		end_slot = parent_nritems - 1;

		if (parent_nritems == 1)
		if (parent_nritems <= 1)
		return 0;

		btrfs_set_lock_blocking(parent);

		for (i = start_slot; i < end_slot; i++) {
		for (i = start_slot; i <= end_slot; i++) {
		int close = 1;

		btrfs_node_key(parent, &disk_key, i);
		@@ -1669,7 +1669,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
		other = btrfs_node_blockptr(parent, i - 1);
		close = close_blocks(blocknr, other, blocksize);
		}
		if (!close && i < end_slot - 2) {
		if (!close && i < end_slot) {
		other = btrfs_node_blockptr(parent, i + 1);
		close = close_blocks(blocknr, other, blocksize);
		}

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