From: Chris Mason <chris.mason@oracle.com>
Date: Fri, 27 Apr 2012 18:31:29 +0000 (-0400)
Subject: Btrfs: reduce lock contention during extent insertion
X-Git-Tag: v3.4-rc5~6^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc7fdde39e4962b1a88741f7eba2a6b3be1285d8;p=pandora-kernel.git

Btrfs: reduce lock contention during extent insertion

We're spending huge amounts of time on lock contention during
end_io processing because we unconditionally assume we are overwriting
an existing extent in the file for each IO.

This checks to see if we are outside i_size, and if so, it uses a
less expensive readonly search of the btree to look for existing
extents.

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