Commit 109f6aef authored Apr 02, 2010 by Chris Mason

Btrfs: add check for changed leaves in setup_leaf_for_split



setup_leaf_for_split needs to drop the path and search again, and has
checks to see if the item we want to split changed size.  But, it misses
the case where the leaf changed and now has enough room for the item
we want to insert.

This adds an extra check to make sure the leaf really needs splitting
before we call btrfs_split_leaf(), which keeps us from trying to split
a leaf with a single item.

btrfs_split_leaf() will blindly split the single item leaf, leaving us
with one good leaf and one empty leaf and then a crash.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

parent 6bdb72de

fs/btrfs/ctree.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -3040,6 +3040,10 @@ static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
		if (ret > 0 \|\| item_size != btrfs_item_size_nr(leaf, path->slots[0]))
		goto err;

		/* the leaf has changed, it now has room. return now */
		if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len)
		goto err;

		if (key.type == BTRFS_EXTENT_DATA_KEY) {
		fi = btrfs_item_ptr(leaf, path->slots[0],
		struct btrfs_file_extent_item);

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