From 7a10f0177e117e9935ee9e5c595fcf3c57215de5 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Mon, 24 Jul 2017 19:46:29 -0700 Subject: [PATCH] f2fs: don't give partially written atomic data from process crash This patch resolves the below scenario. == Process 1 == == Process 2 == open(w) open(rw) begin write(new_#1) process_crash f_op->flush locks_remove_posix f_op>release read (new_#1) In order to avoid corrupted database caused by new_#1, we must do roll-back at process_crash time. In order to check that, this patch keeps task which triggers transaction begin, and does roll-back in f_op->flush before removing file locks. Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 1 + fs/f2fs/file.c | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 70777a889e12..859ff4265c34 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -536,6 +536,7 @@ struct f2fs_inode_info { struct list_head dirty_list; /* dirty list for dirs and files */ struct list_head gdirty_list; /* linked in global dirty list */ struct list_head inmem_pages; /* inmemory pages managed by f2fs */ + struct task_struct *inmem_task; /* store inmemory task */ struct mutex inmem_lock; /* lock for inmemory pages */ struct extent_tree *extent_tree; /* cached extent_tree entry */ struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */ diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 2706130c261b..75b3fda99e55 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1495,6 +1495,22 @@ static int f2fs_release_file(struct inode *inode, struct file *filp) return 0; } +static int f2fs_file_flush(struct file *file, fl_owner_t id) +{ + struct inode *inode = file_inode(file); + + /* + * If the process doing a transaction is crashed, we should do + * roll-back. Otherwise, other reader/write can see corrupted database + * until all the writers close its file. Since this should be done + * before dropping file lock, it needs to do in ->flush. + */ + if (f2fs_is_atomic_file(inode) && + F2FS_I(inode)->inmem_task == current) + drop_inmem_pages(inode); + return 0; +} + #define F2FS_REG_FLMASK (~(FS_DIRSYNC_FL | FS_TOPDIR_FL)) #define F2FS_OTHER_FLMASK (FS_NODUMP_FL | FS_NOATIME_FL) @@ -1614,6 +1630,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) } inc_stat: + F2FS_I(inode)->inmem_task = current; stat_inc_atomic_write(inode); stat_update_max_atomic_write(inode); out: @@ -2506,6 +2523,7 @@ const struct file_operations f2fs_file_operations = { .open = f2fs_file_open, .release = f2fs_release_file, .mmap = f2fs_file_mmap, + .flush = f2fs_file_flush, .fsync = f2fs_sync_file, .fallocate = f2fs_fallocate, .unlocked_ioctl = f2fs_ioctl, -- 2.20.1