On Sat, 12 Jan 2013 19:34:48 +0400, Vyacheslav Dubeyko wrote: > From: Vyacheslav Dubeyko <[email protected]> > Subject: [PATCH] nilfs2: fix very long mount time issue > > DESCRIPTION: > It exists 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=<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. > > 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 <[email protected]> > Signed-off-by: Vyacheslav Dubeyko <[email protected]> > Tested-by: Vyacheslav Dubeyko <[email protected]>
Acked-by: Ryusuke Konishi <[email protected]> Thanks, Vyacheslav. I confirmed the issue and could reproduce it. Your patch fixed it. Andrew, please apply. Thanks, Ryusuke Konishi > --- > 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 fdb1807..f385935 100644 > --- a/fs/nilfs2/ioctl.c > +++ b/fs/nilfs2/ioctl.c > @@ -664,8 +664,11 @@ 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); > + } > > nilfs_remove_all_gcinodes(nilfs); > clear_nilfs_gc_running(nilfs); > -- > 1.7.9.5 > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
