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>

5 files changed, 111 insertions, 42 deletions

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 4e59c8219dde..906b5876dc27 100644
--- a/fs/f2fs/dir.c
+++ b/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
@@ -561,26 +560,31 @@ start:
 add_dentry:
         f2fs_wait_on_page_writeback(dentry_page, DATA);
 
-        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;
+        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);
 
-        /* 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);
+        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:
-        up_write(&F2FS_I(inode)->i_sem);
+        if (inode)
+                up_write(&F2FS_I(inode)->i_sem);
 
         if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {
                 update_inode_page(dir);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 0be198339c3b..053361ace0ec 100644
--- a/fs/f2fs/f2fs.h
+++ b/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 *);
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 8241a87046c3..8140e4f0e538 100644
--- a/fs/f2fs/inline.c
+++ b/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);
@@ -417,29 +417,34 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name,
                 goto out;
         }
 
-        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;
+        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 */
-        F2FS_I(inode)->i_pino = dir->i_ino;
-        update_inode(inode, page);
-        f2fs_put_page(page, 1);
+        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:
-        up_write(&F2FS_I(inode)->i_sem);
+        if (inode)
+                up_write(&F2FS_I(inode)->i_sem);
 
         if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {
                 update_inode(dir, ipage);
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 1e2ae21bd6b6..8055e30eb14d 100644
--- a/fs/f2fs/namei.c
+++ b/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);
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index c69de88a6453..679c465e9def 100644
--- a/fs/f2fs/recovery.c
+++ b/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;