From: Jens Axboe Date: Mon, 17 May 2010 10:55:07 +0000 (+0200) Subject: writeback: fix WB_SYNC_NONE writeback from umount X-Git-Tag: v2.6.35-rc1~442^2~55 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e913fc825dc685a444cb4c1d0f9d32f372f59861;p=pandora-kernel.git writeback: fix WB_SYNC_NONE writeback from umount When umount calls sync_filesystem(), we first do a WB_SYNC_NONE writeback to kick off writeback of pending dirty inodes, then follow that up with a WB_SYNC_ALL to wait for it. Since umount already holds the sb s_umount mutex, WB_SYNC_NONE ends up doing nothing and all writeback happens as WB_SYNC_ALL. This can greatly slow down umount, since WB_SYNC_ALL writeback is a data integrity operation and thus a bigger hammer than simple WB_SYNC_NONE. For barrier aware file systems it's a lot slower. Signed-off-by: Jens Axboe --- Reading git-diff-tree failed