From 8c26c4e2694a163d525976e804d81cd955bbb40c Mon Sep 17 00:00:00 2001 From: Vyacheslav Dubeyko Date: Tue, 30 Apr 2013 15:27:48 -0700 Subject: nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption The NILFS2 driver remounts itself in RO mode in the case of discovering metadata corruption (for example, discovering a broken bmap). But usually, this takes place when there have been file system operations before remounting in RO mode. Thereby, NILFS2 driver can be in RO mode with presence of dirty pages in modified inodes' address spaces. It results in flush kernel thread's infinite trying to flush dirty pages in RO mode. As a result, it is possible to see such side effects as: (1) flush kernel thread occupies 50% - 99% of CPU time; (2) system can't be shutdowned without manual power switch off. SYMPTOMS: (1) System log contains error message: "Remounting filesystem read-only". (2) The flush kernel thread occupies 50% - 99% of CPU time. (3) The system can't be shutdowned without manual power switch off. REPRODUCTION PATH: (1) Create volume group with name "unencrypted" by means of vgcreate utility. (2) Run script (prepared by Anthony Doggett ): ----------------[BEGIN SCRIPT]-------------------- #!/bin/bash VG=unencrypted #apt-get install nilfs-tools darcs lvcreate --size 2G --name ntest $VG mkfs.nilfs2 -b 1024 -B 8192 /dev/mapper/$VG-ntest mkdir /var/tmp/n mkdir /var/tmp/n/ntest mount /dev/mapper/$VG-ntest /var/tmp/n/ntest mkdir /var/tmp/n/ntest/thedir cd /var/tmp/n/ntest/thedir sleep 2 date darcs init sleep 2 dmesg|tail -n 5 date darcs whatsnew || true date sleep 2 dmesg|tail -n 5 ----------------[END SCRIPT]-------------------- (3) Try to shutdown the system. REPRODUCIBILITY: 100% FIX: This patch implements checking mount state of NILFS2 driver in nilfs_writepage(), nilfs_writepages() and nilfs_mdt_write_page() methods. If it is detected the RO mount state then all dirty pages are simply discarded with warning messages is written in system log. [akpm@linux-foundation.org: fix printk warning] Signed-off-by: Vyacheslav Dubeyko Acked-by: Ryusuke Konishi Cc: Anthony Doggett Cc: ARAI Shun-ichi Cc: Piotr Szymaniak Cc: Zahid Chowdhury Cc: Elmer Zhang Cc: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nilfs2/page.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/nilfs2/page.h') diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h index fb7de71605a0..ef30c5c2426f 100644 --- a/fs/nilfs2/page.h +++ b/fs/nilfs2/page.h @@ -55,7 +55,8 @@ void nilfs_page_bug(struct page *); int nilfs_copy_dirty_pages(struct address_space *, struct address_space *); void nilfs_copy_back_pages(struct address_space *, struct address_space *); -void nilfs_clear_dirty_pages(struct address_space *); +void nilfs_clear_dirty_page(struct page *, bool); +void nilfs_clear_dirty_pages(struct address_space *, bool); void nilfs_mapping_init(struct address_space *mapping, struct inode *inode, struct backing_dev_info *bdi); unsigned nilfs_page_count_clean_buffers(struct page *, unsigned, unsigned); -- cgit v1.2.3-58-ga151