Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 10/26] nilfs2: fix fix very long mount time issue | Date | Thu, 7 Feb 2013 16:57:38 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Vyacheslav Dubeyko <slava@dubeyko.com>
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=<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 <splavgm@gmail.com> Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com> Tested-by: Vyacheslav Dubeyko <slava@dubeyko.com> Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/nilfs2/ioctl.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/fs/nilfs2/ioctl.c +++ b/fs/nilfs2/ioctl.c @@ -666,8 +666,11 @@ static int nilfs_ioctl_clean_segments(st 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);
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