f2fs: add F2FS_INLINE_DOTS to recover missing dot dentries

If f2fs was corrupted with missing dot dentries, it needs to recover them after
fsck.f2fs detection.

The underlying precedure is:

1. The fsck.f2fs remains F2FS_INLINE_DOTS flag in directory inode, if it detects
missing dot dentries.

2. When f2fs looks up the corrupted directory, it triggers f2fs_add_link with
proper inode numbers and their dot and dotdot names.

3. Once f2fs recovers the directory without errors, it removes F2FS_INLINE_DOTS
finally.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/dir.c

@@ -59,9 +59,8 @@ static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
 	[S_IFLNK >> S_SHIFT]	= F2FS_FT_SYMLINK,
 };
 
-void set_de_type(struct f2fs_dir_entry *de, struct inode *inode)
+void set_de_type(struct f2fs_dir_entry *de, umode_t mode)
 {
-	umode_t mode = inode->i_mode;
 	de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
 }
 
@@ -282,7 +281,7 @@ void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
 	lock_page(page);
 	f2fs_wait_on_page_writeback(page, type);
 	de->ino = cpu_to_le32(inode->i_ino);
-	set_de_type(de, inode);
+	set_de_type(de, inode->i_mode);
 	f2fs_dentry_kunmap(dir, page);
 	set_page_dirty(page);
 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
@@ -328,14 +327,14 @@ void do_make_empty_dir(struct inode *inode, struct inode *parent,
 	de->hash_code = 0;
 	de->ino = cpu_to_le32(inode->i_ino);
 	memcpy(d->filename[0], ".", 1);
-	set_de_type(de, inode);
+	set_de_type(de, inode->i_mode);
 
 	de = &d->dentry[1];
 	de->hash_code = 0;
 	de->name_len = cpu_to_le16(2);
 	de->ino = cpu_to_le32(parent->i_ino);
 	memcpy(d->filename[1], "..", 2);
-	set_de_type(de, inode);
+	set_de_type(de, inode->i_mode);
 
 	test_and_set_bit_le(0, (void *)d->bitmap);
 	test_and_set_bit_le(1, (void *)d->bitmap);
@@ -432,7 +431,7 @@ error:
 void update_parent_metadata(struct inode *dir, struct inode *inode,
 						unsigned int current_depth)
 {
-	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
+	if (inode && is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
 		if (S_ISDIR(inode->i_mode)) {
 			inc_nlink(dir);
 			set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
@@ -447,7 +446,7 @@ void update_parent_metadata(struct inode *dir, struct inode *inode,
 		set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
 	}
 
-	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
+	if (inode && is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
 		clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
 }
 
@@ -471,7 +470,7 @@ next:
 	goto next;
 }
 
-void f2fs_update_dentry(struct inode *inode, struct f2fs_dentry_ptr *d,
+void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
 				const struct qstr *name, f2fs_hash_t name_hash,
 				unsigned int bit_pos)
 {
@@ -483,8 +482,8 @@ void f2fs_update_dentry(struct inode *inode, struct f2fs_dentry_ptr *d,
 	de->hash_code = name_hash;
 	de->name_len = cpu_to_le16(name->len);
 	memcpy(d->filename[bit_pos], name->name, name->len);
-	de->ino = cpu_to_le32(inode->i_ino);
-	set_de_type(de, inode);
+	de->ino = cpu_to_le32(ino);
+	set_de_type(de, mode);
 	for (i = 0; i < slots; i++)
 		test_and_set_bit_le(bit_pos + i, (void *)d->bitmap);
 }
@@ -494,7 +493,7 @@ void f2fs_update_dentry(struct inode *inode, struct f2fs_dentry_ptr *d,
  * f2fs_unlock_op().
  */
 int __f2fs_add_link(struct inode *dir, const struct qstr *name,
-						struct inode *inode)
+				struct inode *inode, nid_t ino, umode_t mode)
 {
 	unsigned int bit_pos;
 	unsigned int level;
@@ -507,11 +506,11 @@ int __f2fs_add_link(struct inode *dir, const struct qstr *name,
 	struct f2fs_dentry_block *dentry_blk = NULL;
 	struct f2fs_dentry_ptr d;
 	int slots = GET_DENTRY_SLOTS(namelen);
-	struct page *page;
+	struct page *page = NULL;
 	int err = 0;
 
 	if (f2fs_has_inline_dentry(dir)) {
-		err = f2fs_add_inline_entry(dir, name, inode);
+		err = f2fs_add_inline_entry(dir, name, inode, ino, mode);
 		if (!err || err != -EAGAIN)
 			return err;
 		else
@@ -561,25 +560,30 @@ start:
 add_dentry:
 	f2fs_wait_on_page_writeback(dentry_page, DATA);
 
+	if (inode) {
 		down_write(&F2FS_I(inode)->i_sem);
 		page = init_inode_metadata(inode, dir, name, NULL);
 		if (IS_ERR(page)) {
 			err = PTR_ERR(page);
 			goto fail;
 		}
+	}
 
 	make_dentry_ptr(&d, (void *)dentry_blk, 1);
-	f2fs_update_dentry(inode, &d, name, dentry_hash, bit_pos);
+	f2fs_update_dentry(ino, mode, &d, name, dentry_hash, bit_pos);
 
 	set_page_dirty(dentry_page);
 
+	if (inode) {
 		/* we don't need to mark_inode_dirty now */
 		F2FS_I(inode)->i_pino = dir->i_ino;
 		update_inode(inode, page);
 		f2fs_put_page(page, 1);
+	}
 
 	update_parent_metadata(dir, inode, current_depth);
 fail:
+	if (inode)
 		up_write(&F2FS_I(inode)->i_sem);
 
 	if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {

fs/f2fs/f2fs.h

@@ -1246,6 +1246,7 @@ enum {
 	FI_FIRST_BLOCK_WRITTEN,	/* indicate #0 data block was written */
 	FI_DROP_CACHE,		/* drop dirty page cache */
 	FI_DATA_EXIST,		/* indicate data exists */
+	FI_INLINE_DOTS,		/* indicate inline dot dentries */
 };
 
 static inline void set_inode_flag(struct f2fs_inode_info *fi, int flag)
@@ -1282,6 +1283,8 @@ static inline void get_inline_info(struct f2fs_inode_info *fi,
 		set_inode_flag(fi, FI_INLINE_DENTRY);
 	if (ri->i_inline & F2FS_DATA_EXIST)
 		set_inode_flag(fi, FI_DATA_EXIST);
+	if (ri->i_inline & F2FS_INLINE_DOTS)
+		set_inode_flag(fi, FI_INLINE_DOTS);
 }
 
 static inline void set_raw_inline(struct f2fs_inode_info *fi,
@@ -1297,6 +1300,8 @@ static inline void set_raw_inline(struct f2fs_inode_info *fi,
 		ri->i_inline |= F2FS_INLINE_DENTRY;
 	if (is_inode_flag_set(fi, FI_DATA_EXIST))
 		ri->i_inline |= F2FS_DATA_EXIST;
+	if (is_inode_flag_set(fi, FI_INLINE_DOTS))
+		ri->i_inline |= F2FS_INLINE_DOTS;
 }
 
 static inline int f2fs_has_inline_xattr(struct inode *inode)
@@ -1342,6 +1347,11 @@ static inline int f2fs_exist_data(struct inode *inode)
 	return is_inode_flag_set(F2FS_I(inode), FI_DATA_EXIST);
 }
 
+static inline int f2fs_has_inline_dots(struct inode *inode)
+{
+	return is_inode_flag_set(F2FS_I(inode), FI_INLINE_DOTS);
+}
+
 static inline bool f2fs_is_atomic_file(struct inode *inode)
 {
 	return is_inode_flag_set(F2FS_I(inode), FI_ATOMIC_FILE);
@@ -1440,7 +1450,7 @@ struct dentry *f2fs_get_parent(struct dentry *child);
  * dir.c
  */
 extern unsigned char f2fs_filetype_table[F2FS_FT_MAX];
-void set_de_type(struct f2fs_dir_entry *, struct inode *);
+void set_de_type(struct f2fs_dir_entry *, umode_t);
 struct f2fs_dir_entry *find_target_dentry(struct qstr *, int *,
 			struct f2fs_dentry_ptr *);
 bool f2fs_fill_dentries(struct dir_context *, struct f2fs_dentry_ptr *,
@@ -1459,9 +1469,10 @@ ino_t f2fs_inode_by_name(struct inode *, struct qstr *);
 void f2fs_set_link(struct inode *, struct f2fs_dir_entry *,
 				struct page *, struct inode *);
 int update_dent_inode(struct inode *, const struct qstr *);
-void f2fs_update_dentry(struct inode *, struct f2fs_dentry_ptr *,
+void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *,
 			const struct qstr *, f2fs_hash_t , unsigned int);
-int __f2fs_add_link(struct inode *, const struct qstr *, struct inode *);
+int __f2fs_add_link(struct inode *, const struct qstr *, struct inode *, nid_t,
+			umode_t);
 void f2fs_delete_entry(struct f2fs_dir_entry *, struct page *, struct inode *,
 							struct inode *);
 int f2fs_do_tmpfile(struct inode *, struct inode *);
@@ -1471,7 +1482,7 @@ bool f2fs_empty_dir(struct inode *);
 static inline int f2fs_add_link(struct dentry *dentry, struct inode *inode)
 {
 	return __f2fs_add_link(dentry->d_parent->d_inode, &dentry->d_name,
-				inode);
+				inode, inode->i_ino, inode->i_mode);
 }
 
 /*
@@ -1792,7 +1803,8 @@ struct f2fs_dir_entry *find_in_inline_dir(struct inode *, struct qstr *,
 							struct page **);
 struct f2fs_dir_entry *f2fs_parent_inline_dir(struct inode *, struct page **);
 int make_empty_inline_dir(struct inode *inode, struct inode *, struct page *);
-int f2fs_add_inline_entry(struct inode *, const struct qstr *, struct inode *);
+int f2fs_add_inline_entry(struct inode *, const struct qstr *, struct inode *,
+						nid_t, umode_t);
 void f2fs_delete_inline_entry(struct f2fs_dir_entry *, struct page *,
 						struct inode *, struct inode *);
 bool f2fs_empty_inline_dir(struct inode *);

fs/f2fs/inline.c

@@ -390,7 +390,7 @@ out:
 }
 
 int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name,
-						struct inode *inode)
+			struct inode *inode, nid_t ino, umode_t mode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
 	struct page *ipage;
@@ -400,7 +400,7 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name,
 	struct f2fs_inline_dentry *dentry_blk = NULL;
 	struct f2fs_dentry_ptr d;
 	int slots = GET_DENTRY_SLOTS(namelen);
-	struct page *page;
+	struct page *page = NULL;
 	int err = 0;
 
 	ipage = get_node_page(sbi, dir->i_ino);
@@ -417,28 +417,33 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name,
 		goto out;
 	}
 
+	if (inode) {
 		down_write(&F2FS_I(inode)->i_sem);
 		page = init_inode_metadata(inode, dir, name, ipage);
 		if (IS_ERR(page)) {
 			err = PTR_ERR(page);
 			goto fail;
 		}
+	}
 
 	f2fs_wait_on_page_writeback(ipage, NODE);
 
 	name_hash = f2fs_dentry_hash(name);
 	make_dentry_ptr(&d, (void *)dentry_blk, 2);
-	f2fs_update_dentry(inode, &d, name, name_hash, bit_pos);
+	f2fs_update_dentry(ino, mode, &d, name, name_hash, bit_pos);
 
 	set_page_dirty(ipage);
 
 	/* we don't need to mark_inode_dirty now */
+	if (inode) {
 		F2FS_I(inode)->i_pino = dir->i_ino;
 		update_inode(inode, page);
 		f2fs_put_page(page, 1);
+	}
 
 	update_parent_metadata(dir, inode, 0);
 fail:
+	if (inode)
 		up_write(&F2FS_I(inode)->i_sem);
 
 	if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {

fs/f2fs/namei.c

@@ -187,6 +187,44 @@ struct dentry *f2fs_get_parent(struct dentry *child)
 	return d_obtain_alias(f2fs_iget(child->d_inode->i_sb, ino));
 }
 
+static int __recover_dot_dentries(struct inode *dir, nid_t pino)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
+	struct qstr dot = QSTR_INIT(".", 1);
+	struct qstr dotdot = QSTR_INIT("..", 2);
+	struct f2fs_dir_entry *de;
+	struct page *page;
+	int err = 0;
+
+	f2fs_lock_op(sbi);
+
+	de = f2fs_find_entry(dir, &dot, &page);
+	if (de) {
+		f2fs_dentry_kunmap(dir, page);
+		f2fs_put_page(page, 0);
+	} else {
+		err = __f2fs_add_link(dir, &dot, NULL, dir->i_ino, S_IFDIR);
+		if (err)
+			goto out;
+	}
+
+	de = f2fs_find_entry(dir, &dotdot, &page);
+	if (de) {
+		f2fs_dentry_kunmap(dir, page);
+		f2fs_put_page(page, 0);
+	} else {
+		err = __f2fs_add_link(dir, &dotdot, NULL, pino, S_IFDIR);
+	}
+out:
+	if (!err) {
+		clear_inode_flag(F2FS_I(dir), FI_INLINE_DOTS);
+		mark_inode_dirty(dir);
+	}
+
+	f2fs_unlock_op(sbi);
+	return err;
+}
+
 static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 		unsigned int flags)
 {
@@ -206,6 +244,16 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 		inode = f2fs_iget(dir->i_sb, ino);
 		if (IS_ERR(inode))
 			return ERR_CAST(inode);
+
+		if (f2fs_has_inline_dots(inode)) {
+			int err;
+
+			err = __recover_dot_dentries(inode, dir->i_ino);
+			if (err) {
+				iget_failed(inode);
+				return ERR_PTR(err);
+			}
+		}
 	}
 
 	return d_splice_alias(inode, dentry);

fs/f2fs/recovery.c

@@ -115,7 +115,7 @@ retry:
 		iput(einode);
 		goto retry;
 	}
-	err = __f2fs_add_link(dir, &name, inode);
+	err = __f2fs_add_link(dir, &name, inode, inode->i_ino, inode->i_mode);
 	if (err)
 		goto out_err;
 

include/linux/f2fs_fs.h

@@ -178,6 +178,7 @@ struct f2fs_extent {
 #define F2FS_INLINE_DATA	0x02	/* file inline data flag */
 #define F2FS_INLINE_DENTRY	0x04	/* file inline dentry flag */
 #define F2FS_DATA_EXIST		0x08	/* file inline data exist flag */
+#define F2FS_INLINE_DOTS	0x10	/* file having implicit dot dentries */
 
 #define MAX_INLINE_DATA		(sizeof(__le32) * (DEF_ADDRS_PER_INODE - \
 						F2FS_INLINE_XATTR_ADDRS - 1))