tree bc567aa83da6d709d3762f7e0bf9a5fe4d16de11
parent f9295749388f82c8d2f485e99c72cd7c7876a99b
author Chris Mason <chris.mason@oracle.com> 1216313655 -0400
committer Chris Mason <chris.mason@oracle.com> 1222355044 -0400

Btrfs: Don't pin pages in ram until the entire ordered extent is on disk.

Checksum items are not inserted until the entire ordered extent is on disk,
but individual pages might be clean and available for reclaim long before
the whole extent is on disk.

In order to allow those pages to be freed, we need to be able to search
the list of ordered extents to find the checksum that is going to be inserted
in the tree.  This way if the page needs to be read back in before
the checksums are in the btree, we'll be able to verify the checksum on
the page.

This commit adds the ability to search the pending ordered extents for
a given offset in the file, and changes btrfs_releasepage to allow
ordered pages to be freed.

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