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/gc.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'fs/f2fs/gc.c') 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); } } -- cgit v1.2.3