f2fs: recover wrong pino after checkpoint during fsync

If a file is linked, f2fs loose its parent inode number so that fsync calls
for the linked file should do checkpoint all the time.
But, if we can recover its parent inode number after the checkpoint, we can
adjust roll-forward mechanism for the further fsync calls, which is able to
improve the fsync performance significatly.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/dir.c

@@ -356,7 +356,7 @@ static struct page *init_inode_metadata(struct inode *inode,
 	 * We lost i_pino from now on.
 	 */
 	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
-		set_cp_file(inode);
+		file_lost_pino(inode);
 		inc_nlink(inode);
 	}
 	return page;

fs/f2fs/f2fs.h

@@ -151,7 +151,7 @@ struct extent_info {
  * i_advise uses FADVISE_XXX_BIT. We can add additional hints later.
  */
 #define FADVISE_COLD_BIT	0x01
-#define FADVISE_CP_BIT		0x02
+#define FADVISE_LOST_PINO_BIT	0x02
 
 struct f2fs_inode_info {
 	struct inode vfs_inode;		/* serve a vfs inode */

fs/f2fs/file.c

@@ -102,6 +102,24 @@ static const struct vm_operations_struct f2fs_file_vm_ops = {
 	.remap_pages	= generic_file_remap_pages,
 };
 
+static int get_parent_ino(struct inode *inode, nid_t *pino)
+{
+	struct dentry *dentry;
+
+	inode = igrab(inode);
+	dentry = d_find_any_alias(inode);
+	iput(inode);
+	if (!dentry)
+		return 0;
+
+	inode = igrab(dentry->d_parent->d_inode);
+	dput(dentry);
+
+	*pino = inode->i_ino;
+	iput(inode);
+	return 1;
+}
+
 int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 {
 	struct inode *inode = file->f_mapping->host;
@@ -134,7 +152,7 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 
 	if (!S_ISREG(inode->i_mode) || inode->i_nlink != 1)
 		need_cp = true;
-	else if (is_cp_file(inode))
+	else if (file_wrong_pino(inode))
 		need_cp = true;
 	else if (!space_for_roll_forward(sbi))
 		need_cp = true;
@@ -142,8 +160,19 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		need_cp = true;
 
 	if (need_cp) {
+		nid_t pino;
+
 		/* all the dirty node pages should be flushed for POR */
 		ret = f2fs_sync_fs(inode->i_sb, 1);
+		if (file_wrong_pino(inode) && inode->i_nlink == 1 &&
+					get_parent_ino(inode, &pino)) {
+			F2FS_I(inode)->i_pino = pino;
+			file_got_pino(inode);
+			mark_inode_dirty_sync(inode);
+			ret = f2fs_write_inode(inode, NULL);
+			if (ret)
+				goto out;
+		}
 	} else {
 		/* if there is no written node page, write its inode page */
 		while (!sync_node_pages(sbi, inode->i_ino, &wbc)) {

fs/f2fs/namei.c

@@ -112,7 +112,7 @@ static inline void set_cold_files(struct f2fs_sb_info *sbi, struct inode *inode,
 	int count = le32_to_cpu(sbi->raw_super->extension_count);
 	for (i = 0; i < count; i++) {
 		if (is_multimedia_file(name, extlist[i])) {
-			set_cold_file(inode);
+			file_set_cold(inode);
 			break;
 		}
 	}

fs/f2fs/node.h

@@ -285,10 +285,17 @@ static inline void set_file(struct inode *inode, int type)
 	F2FS_I(inode)->i_advise |= type;
 }
 
-#define is_cold_file(inode)	is_file(inode, FADVISE_COLD_BIT)
-#define is_cp_file(inode)	is_file(inode, FADVISE_CP_BIT)
-#define set_cold_file(inode)	set_file(inode, FADVISE_COLD_BIT)
-#define set_cp_file(inode)	set_file(inode, FADVISE_CP_BIT)
+static inline void clear_file(struct inode *inode, int type)
+{
+	F2FS_I(inode)->i_advise &= ~type;
+}
+
+#define file_is_cold(inode)	is_file(inode, FADVISE_COLD_BIT)
+#define file_wrong_pino(inode)	is_file(inode, FADVISE_LOST_PINO_BIT)
+#define file_set_cold(inode)	set_file(inode, FADVISE_COLD_BIT)
+#define file_lost_pino(inode)	set_file(inode, FADVISE_LOST_PINO_BIT)
+#define file_clear_cold(inode)	clear_file(inode, FADVISE_COLD_BIT)
+#define file_got_pino(inode)	clear_file(inode, FADVISE_LOST_PINO_BIT)
 
 static inline int is_cold_data(struct page *page)
 {

fs/f2fs/segment.c

@@ -796,7 +796,7 @@ static int __get_segment_type_6(struct page *page, enum page_type p_type)
 
 		if (S_ISDIR(inode->i_mode))
 			return CURSEG_HOT_DATA;
-		else if (is_cold_data(page) || is_cold_file(inode))
+		else if (is_cold_data(page) || file_is_cold(inode))
 			return CURSEG_COLD_DATA;
 		else
 			return CURSEG_WARM_DATA;