From 82e0a5aa5ddf794b3e1b21fcd091228736871882 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Wed, 13 Jul 2016 09:18:29 +0800 Subject: f2fs: fix to avoid data update racing between GC and DIO Datas in file can be operated by GC and DIO simultaneously, so we will face race case as below: For write case: Thread A Thread B - generic_file_direct_write - invalidate_inode_pages2_range - f2fs_direct_IO - do_blockdev_direct_IO - do_direct_IO - get_more_blocks - f2fs_gc - do_garbage_collect - gc_data_segment - move_data_page - do_write_data_page migrate data block to new block address - dio_bio_submit update user data to old block address For read case: Thread A Thread B - generic_file_direct_write - invalidate_inode_pages2_range - f2fs_direct_IO - do_blockdev_direct_IO - do_direct_IO - get_more_blocks - f2fs_balance_fs - f2fs_gc - do_garbage_collect - gc_data_segment - move_data_page - do_write_data_page migrate data block to new block address - write_checkpoint - do_checkpoint - clear_prefree_segments - f2fs_issue_discard discard old block adress - dio_bio_submit update user buffer from obsolete block address In order to fix this, for one file, we should let DIO and GC getting exclusion against with each other. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 6 +++++- fs/f2fs/f2fs.h | 1 + fs/f2fs/gc.c | 20 ++++++++++++++++++++ fs/f2fs/super.c | 2 ++ 4 files changed, 28 insertions(+), 1 deletion(-) (limited to 'fs/f2fs') diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 650099597dd2..adfe47b21991 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1716,6 +1716,7 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) struct inode *inode = mapping->host; size_t count = iov_iter_count(iter); loff_t offset = iocb->ki_pos; + int rw = iov_iter_rw(iter); int err; err = check_direct_IO(inode, iter, offset); @@ -1729,8 +1730,11 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter)); + down_read(&F2FS_I(inode)->dio_rwsem[rw]); err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio); - if (iov_iter_rw(iter) == WRITE) { + up_read(&F2FS_I(inode)->dio_rwsem[rw]); + + if (rw == WRITE) { if (err > 0) set_inode_flag(inode, FI_UPDATE_WRITE); else if (err < 0) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index b4a46b6823dc..211183c4e5c3 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -454,6 +454,7 @@ struct f2fs_inode_info { struct list_head inmem_pages; /* inmemory pages managed by f2fs */ 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 */ }; static inline void get_extent_info(struct extent_info *ext, diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index c61213785914..5c8acf754513 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -755,12 +755,32 @@ next_step: /* phase 3 */ inode = find_gc_inode(gc_list, dni.ino); if (inode) { + struct f2fs_inode_info *fi = F2FS_I(inode); + bool locked = false; + + if (S_ISREG(inode->i_mode)) { + if (!down_write_trylock(&fi->dio_rwsem[READ])) + continue; + if (!down_write_trylock( + &fi->dio_rwsem[WRITE])) { + up_write(&fi->dio_rwsem[READ]); + continue; + } + locked = true; + } + start_bidx = start_bidx_of_node(nofs, inode) + ofs_in_node; if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) move_encrypted_block(inode, start_bidx); else move_data_page(inode, start_bidx, gc_type); + + if (locked) { + up_write(&fi->dio_rwsem[WRITE]); + up_write(&fi->dio_rwsem[READ]); + } + stat_inc_data_blk_count(sbi, 1, gc_type); } } diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 451dfb4041e8..b97c065cbe74 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -579,6 +579,8 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb) INIT_LIST_HEAD(&fi->gdirty_list); INIT_LIST_HEAD(&fi->inmem_pages); mutex_init(&fi->inmem_lock); + init_rwsem(&fi->dio_rwsem[READ]); + init_rwsem(&fi->dio_rwsem[WRITE]); /* Will be used by directory only */ fi->i_dir_level = F2FS_SB(sb)->dir_level; -- cgit