Patchwork [3.5.y.z,extended,stable] Patch "nilfs2: fix fix very long mount time issue" has been added to staging queue

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Submitter Herton Ronaldo Krzesinski
Date Feb. 12, 2013, 9:19 p.m.
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Permalink /patch/219987/
State New
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Herton Ronaldo Krzesinski - Feb. 12, 2013, 9:19 p.m.
This is a note to let you know that I have just added a patch titled

    nilfs2: fix fix very long mount time issue

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see



From dd158c6f6fe84f26c16319142037d868e41a443b Mon Sep 17 00:00:00 2001
From: Vyacheslav Dubeyko <>
Date: Mon, 4 Feb 2013 14:28:41 -0800
Subject: [PATCH] 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.


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


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=<file_name> 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.



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: Herton Ronaldo Krzesinski <>
 fs/nilfs2/ioctl.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)



diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 0b6387c..29990c9 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -666,8 +666,11 @@  static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 	if (ret < 0)
 		printk(KERN_ERR "NILFS: GC failed during preparation: "
 			"cannot read source blocks: err=%d\n", ret);
-	else
+	else {
+		if (nilfs_sb_need_update(nilfs))
+			set_nilfs_discontinued(nilfs);
 		ret = nilfs_clean_segments(inode->i_sb, argv, kbufs);
+	}