This is a note to let you know that I've just added the patch titled f2fs: fix to update time in lazytime mode to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: f2fs-fix-to-update-time-in-lazytime-mode.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 3c0b487e39d7ade36219f7faccd72f40a4fee340 Author: Chao Yu <yuchao0@xxxxxxxxxx> Date: Fri Sep 27 18:01:35 2019 +0800 f2fs: fix to update time in lazytime mode [ Upstream commit fe1897eaa6646f5a64a4cee0e6473ed9887d324b ] generic/018 reports an inconsistent status of atime, the testcase is as below: - open file with O_SYNC - write file to construct fraged space - calc md5 of file - record {a,c,m}time - defrag file --- do nothing - umount & mount - check {a,c,m}time The root cause is, as f2fs enables lazytime by default, atime update will dirty vfs inode, rather than dirtying f2fs inode (by set with FI_DIRTY_INODE), so later f2fs_write_inode() called from VFS will fail to update inode page due to our skip: f2fs_write_inode() if (is_inode_flag_set(inode, FI_DIRTY_INODE)) return 0; So eventually, after evict(), we lose last atime for ever. To fix this issue, we need to check whether {a,c,m,cr}time is consistent in between inode cache and inode page, and only skip f2fs_update_inode() if f2fs inode is not dirty and time is consistent as well. Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 4024790028aa..f078cd20dab8 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -2704,6 +2704,20 @@ static inline void clear_file(struct inode *inode, int type) f2fs_mark_inode_dirty_sync(inode, true); } +static inline bool f2fs_is_time_consistent(struct inode *inode) +{ + if (!timespec64_equal(F2FS_I(inode)->i_disk_time, &inode->i_atime)) + return false; + if (!timespec64_equal(F2FS_I(inode)->i_disk_time + 1, &inode->i_ctime)) + return false; + if (!timespec64_equal(F2FS_I(inode)->i_disk_time + 2, &inode->i_mtime)) + return false; + if (!timespec64_equal(F2FS_I(inode)->i_disk_time + 3, + &F2FS_I(inode)->i_crtime)) + return false; + return true; +} + static inline bool f2fs_skip_inode_update(struct inode *inode, int dsync) { bool ret; @@ -2721,14 +2735,7 @@ static inline bool f2fs_skip_inode_update(struct inode *inode, int dsync) i_size_read(inode) & ~PAGE_MASK) return false; - if (!timespec64_equal(F2FS_I(inode)->i_disk_time, &inode->i_atime)) - return false; - if (!timespec64_equal(F2FS_I(inode)->i_disk_time + 1, &inode->i_ctime)) - return false; - if (!timespec64_equal(F2FS_I(inode)->i_disk_time + 2, &inode->i_mtime)) - return false; - if (!timespec64_equal(F2FS_I(inode)->i_disk_time + 3, - &F2FS_I(inode)->i_crtime)) + if (!f2fs_is_time_consistent(inode)) return false; down_read(&F2FS_I(inode)->i_sem); diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index db4fec30c30d..386ad54c13c3 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -615,7 +615,11 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc) inode->i_ino == F2FS_META_INO(sbi)) return 0; - if (!is_inode_flag_set(inode, FI_DIRTY_INODE)) + /* + * atime could be updated without dirtying f2fs inode in lazytime mode + */ + if (f2fs_is_time_consistent(inode) && + !is_inode_flag_set(inode, FI_DIRTY_INODE)) return 0; if (!f2fs_is_checkpoint_ready(sbi))