f2fs: do not skip writing file meta during fsync

This patch removes data_version check flow during the fsync call.
The original purpose for the use of data_version was to avoid writng inode
pages redundantly by the fsync calls repeatedly.
However, when user can modify file meta and then call fsync, we should not
skip fsync procedure.
So, let's remove this condition check and hope that user triggers in right
manner.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/data.c

@@ -435,7 +435,6 @@ static int f2fs_read_data_pages(struct file *file,
 int do_write_data_page(struct page *page)
 {
 	struct inode *inode = page->mapping->host;
-	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 	block_t old_blk_addr, new_blk_addr;
 	struct dnode_of_data dn;
 	int err = 0;
@@ -465,8 +464,6 @@ int do_write_data_page(struct page *page)
 		write_data_page(inode, page, &dn,
 				old_blk_addr, &new_blk_addr);
 		update_extent_cache(new_blk_addr, &dn);
-		F2FS_I(inode)->data_version =
-			le64_to_cpu(F2FS_CKPT(sbi)->checkpoint_ver);
 	}
 out_writepage:
 	f2fs_put_dnode(&dn);

fs/f2fs/f2fs.h

@@ -159,7 +159,6 @@ struct f2fs_inode_info {
 
 	/* Use below internally in f2fs*/
 	unsigned long flags;		/* use to pass per-file flags */
-	unsigned long long data_version;/* latest version of data for fsync */
 	atomic_t dirty_dents;		/* # of dirty dentry pages */
 	f2fs_hash_t chash;		/* hash value of given file name */
 	unsigned int clevel;		/* maximum level of given file name */

fs/f2fs/file.c

@@ -124,7 +124,6 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 {
 	struct inode *inode = file->f_mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
-	unsigned long long cur_version;
 	int ret = 0;
 	bool need_cp = false;
 	struct writeback_control wbc = {
@@ -148,15 +147,6 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
 		goto out;
 
-	mutex_lock(&sbi->cp_mutex);
-	cur_version = le64_to_cpu(F2FS_CKPT(sbi)->checkpoint_ver);
-	mutex_unlock(&sbi->cp_mutex);
-
-	if (F2FS_I(inode)->data_version != cur_version &&
-					!(inode->i_state & I_DIRTY))
-		goto out;
-	F2FS_I(inode)->data_version--;
-
 	if (!S_ISREG(inode->i_mode) || inode->i_nlink != 1)
 		need_cp = true;
 	else if (is_inode_flag_set(F2FS_I(inode), FI_NEED_CP))

fs/f2fs/inode.c

@@ -80,7 +80,6 @@ static int do_read_inode(struct inode *inode)
 	fi->i_xattr_nid = le32_to_cpu(ri->i_xattr_nid);
 	fi->i_flags = le32_to_cpu(ri->i_flags);
 	fi->flags = 0;
-	fi->data_version = le64_to_cpu(F2FS_CKPT(sbi)->checkpoint_ver) - 1;
 	fi->i_advise = ri->i_advise;
 	fi->i_pino = le32_to_cpu(ri->i_pino);
 	get_extent_info(&fi->ext, ri->i_ext);