Vyacheslav Dubeyko a9bae18954 nilfs2: fix fix very long mount time issue ... 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> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2013-02-05 20:38:46 +11:00
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alloc.c
alloc.h
bmap.c
bmap.h
btnode.c
btnode.h
btree.c
btree.h
cpfile.c
cpfile.h
dat.c
dat.h
dir.c
direct.c
direct.h
export.h
file.c
gcinode.c
ifile.c
ifile.h
inode.c
ioctl.c
Kconfig
Makefile
mdt.c
mdt.h
namei.c
nilfs.h
page.c
page.h
recovery.c
segbuf.c
segbuf.h
segment.c
segment.h
sufile.c
sufile.h
super.c
the_nilfs.c
the_nilfs.h