From: Vyacheslav Dubeyko Date: Mon, 4 Feb 2013 22:28:41 +0000 (-0800) Subject: nilfs2: fix fix very long mount time issue X-Git-Tag: v3.2.39~44 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e3901b7159e8d16908820df789042c26269c211;p=pandora-kernel.git nilfs2: fix fix very long mount time issue commit a9bae189542e71f91e61a4428adf6e5a7dfe8063 upstream. There exists a situation when GC can work in background alone without any other filesystem activity during significant time. The nilfs_clean_segments() method calls nilfs_segctor_construct() that updates superblocks in the case of NILFS_SC_SUPER_ROOT and THE_NILFS_DISCONTINUED flags are set. But when GC is working alone the nilfs_clean_segments() is called with unset THE_NILFS_DISCONTINUED flag. As a result, the update of superblocks doesn't occurred all this time and in the case of SPOR superblocks keep very old values of last super root placement. SYMPTOMS: Trying to mount a NILFS2 volume after SPOR in such environment ends with very long mounting time (it can achieve about several hours in some cases). REPRODUCING PATH: 1. It needs to use external USB HDD, disable automount and doesn't make any additional filesystem activity on the NILFS2 volume. 2. Generate temporary file with size about 100 - 500 GB (for example, dd if=/dev/zero of= bs=1073741824 count=200). The size of file defines duration of GC working. 3. Then it needs to delete file. 4. Start GC manually by means of command "nilfs-clean -p 0". When you start GC by means of such way then, at the end, superblocks is updated by once. So, for simulation of SPOR, it needs to wait sometime (15 - 40 minutes) and simply switch off USB HDD manually. 5. Switch on USB HDD again and try to mount NILFS2 volume. As a result, NILFS2 volume will mount during very long time. REPRODUCIBILITY: 100% FIX: This patch adds checking that superblocks need to update and set THE_NILFS_DISCONTINUED flag before nilfs_clean_segments() call. Reported-by: Sergey Alexandrov Signed-off-by: Vyacheslav Dubeyko Tested-by: Vyacheslav Dubeyko Acked-by: Ryusuke Konishi Tested-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed