From: Jaegeuk Kim Date: Fri, 25 Jan 2013 09:33:41 +0000 (+0900) Subject: f2fs: cover global locks for reserve_new_block X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=bd43df021ac37247f2db58ff376fb4032170f754;p=deliverable%2Flinux.git f2fs: cover global locks for reserve_new_block The fill_zero() from fallocate() calls get_new_data_page() in which calls reserve_new_block(). The reserve_new_block() should be covered by *DATA_NEW*, one of global locks. And also, before getting the lock, we should check free sections by calling f2fs_balance_fs(). If we break this rule, f2fs is able to face with out-of-control free space management and fall into infinite loop like the following scenario as well. [f2fs_sync_fs()] [fallocate()] - write_checkpoint() - fill_zero() - block_operations() - get_new_data_page() : grab NODE_NEW - get_dnode_of_data() : get locked dirty node page - sync_node_pages() : try to grab NODE_NEW for data allocation : trylock and skip the dirty node page : call sync_node_pages() repeatedly in order to flush all the dirty node pages! In order to avoid this, we should grab another global lock such as DATA_NEW before calling get_new_data_page() in fill_zero(). Signed-off-by: Jaegeuk Kim --- diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 3191b52aafb0..6cdab2c64fc6 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -387,12 +387,17 @@ const struct inode_operations f2fs_file_inode_operations = { static void fill_zero(struct inode *inode, pgoff_t index, loff_t start, loff_t len) { + struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb); struct page *page; if (!len) return; + f2fs_balance_fs(sbi); + + mutex_lock_op(sbi, DATA_NEW); page = get_new_data_page(inode, index, false); + mutex_unlock_op(sbi, DATA_NEW); if (!IS_ERR(page)) { wait_on_page_writeback(page);