re: Btrfs: cleanup destroy_marked_extents

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Josef Bacik,

This is a semi-automatic email about new static checker warnings.

The patch fd8b2b611580: "Btrfs: cleanup destroy_marked_extents" from 
Apr 24, 2013, leads to the following Smatch complaint:

fs/btrfs/disk-io.c:3814 btrfs_destroy_marked_extents()
	 warn: variable dereferenced before check 'eb' (see line 3813)

fs/btrfs/disk-io.c
  3812							   root->leafsize);
  3813				start += eb->len;
                                         ^^^^^^^
New dereference.
  3814				if (!eb)
                                    ^^^
New check.  Maybe we should be adding "root->leafsize" here?  Just
the check earlier would cause a forever loop.

  3815					continue;
  3816				wait_on_extent_buffer_writeback(eb);

regards,
dan carpenter