From: Theodore Ts'o <tytso@mit.edu>
Date: Tue, 17 Mar 2015 16:23:19 +0000 (-0400)
Subject: fs: make sure the timestamps for lazytime inodes eventually get written
X-Git-Tag: omap-for-v4.1/fixes-rc1~245^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a2f4870697a5bcf4a87073ec6b32dd2928c1211d;p=pandora-kernel.git

fs: make sure the timestamps for lazytime inodes eventually get written

Jan Kara pointed out that if there is an inode which is constantly
getting dirtied with I_DIRTY_PAGES, an inode with an updated timestamp
will never be written since inode->dirtied_when is constantly getting
updated.  We fix this by adding an extra field to the inode,
dirtied_time_when, so inodes with a stale dirtytime can get detected
and handled.

In addition, if we have a dirtytime inode caused by an atime update,
and there is no write activity on the file system, we need to have a
secondary system to make sure these inodes get written out.  We do
this by setting up a second delayed work structure which wakes up the
CPU much more rarely compared to writeback_expire_centisecs.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
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