Ryusuke Konishi 283ee1482f nilfs2: fix deadlock of segment constructor during recovery ... According to a report from Yuxuan Shui, nilfs2 in kernel 3.19 got stuck during recovery at mount time. The code path that caused the deadlock was as follows: nilfs_fill_super() load_nilfs() nilfs_salvage_orphan_logs() * Do roll-forwarding, attach segment constructor for recovery, and kick it. nilfs_segctor_thread() nilfs_segctor_thread_construct() * A lock is held with nilfs_transaction_lock() nilfs_segctor_do_construct() nilfs_segctor_drop_written_files() iput() iput_final() write_inode_now() writeback_single_inode() __writeback_single_inode() do_writepages() nilfs_writepage() nilfs_construct_dsync_segment() nilfs_transaction_lock() --> deadlock This can happen if commit 7ef3ff2fea ("nilfs2: fix deadlock of segment constructor over I_SYNC flag") is applied and roll-forward recovery was performed at mount time. The roll-forward recovery can happen if datasync write is done and the file system crashes immediately after that. For instance, we can reproduce the issue with the following steps: < nilfs2 is mounted on /nilfs (device: /dev/sdb1) > # dd if=/dev/zero of=/nilfs/test bs=4k count=1 && sync # dd if=/dev/zero of=/nilfs/test conv=notrunc oflag=dsync bs=4k count=1 && reboot -nfh < the system will immediately reboot > # mount -t nilfs2 /dev/sdb1 /nilfs The deadlock occurs because iput() can run segment constructor through writeback_single_inode() if MS_ACTIVE flag is not set on sb->s_flags. The above commit changed segment constructor so that it calls iput() asynchronously for inodes with i_nlink == 0, but that change was imperfect. This fixes the another deadlock by deferring iput() in segment constructor even for the case that mount is not finished, that is, for the case that MS_ACTIVE flag is not set. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Reported-by: Yuxuan Shui <yshuiv7@gmail.com> Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2015-03-12 18:46:08 -07:00
..
alloc.c
alloc.h
bmap.c
bmap.h
btnode.c
btnode.h
btree.c	nilfs2: fix potential memory overrun on inode	2015-02-28 09:57:51 -08:00
btree.h
cpfile.c
cpfile.h
dat.c
dat.h
dir.c
direct.c
direct.h
export.h
file.c	mm: drop vm_ops->remap_pages and generic_file_remap_pages() stub	2015-02-10 14:30:30 -08:00
gcinode.c	fs: remove mapping->backing_dev_info	2015-01-20 14:03:05 -07:00
ifile.c
ifile.h
inode.c	nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races	2014-12-10 17:41:16 -08:00
ioctl.c	nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs()	2014-10-14 02:18:20 +02:00
Kconfig
Makefile	nilfs2: integrate sysfs support into driver	2014-08-08 15:57:21 -07:00
mdt.c	fs: remove mapping->backing_dev_info	2015-01-20 14:03:05 -07:00
mdt.h
namei.c	nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races	2014-12-10 17:41:16 -08:00
nilfs.h	nilfs2: fix deadlock of segment constructor over I_SYNC flag	2015-02-05 13:35:29 -08:00
page.c	fs: remove mapping->backing_dev_info	2015-01-20 14:03:05 -07:00
page.h	fs: remove mapping->backing_dev_info	2015-01-20 14:03:05 -07:00
recovery.c
segbuf.c
segbuf.h
segment.c	nilfs2: fix deadlock of segment constructor during recovery	2015-03-12 18:46:08 -07:00
segment.h	nilfs2: fix deadlock of segment constructor over I_SYNC flag	2015-02-05 13:35:29 -08:00
sufile.c
sufile.h
super.c	fs: remove mapping->backing_dev_info	2015-01-20 14:03:05 -07:00
sysfs.c	nilfs2: integrate sysfs support into driver	2014-08-08 15:57:21 -07:00
sysfs.h	nilfs2: add /sys/fs/nilfs2/<device>/mounted_snapshots/<snapshot> group	2014-08-08 15:57:21 -07:00
the_nilfs.c	nilfs2: deletion of an unnecessary check before the function call "iput"	2014-12-10 17:41:16 -08:00
the_nilfs.h	nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs()	2014-10-14 02:18:20 +02:00