f2fs: fix fs corruption due to zero inode page

This patch fixes the following scenario.

- f2fs_create/f2fs_mkdir             - write_checkpoint
 - f2fs_mark_inode_dirty_sync         - block_operations
                                       - f2fs_lock_all
                                       - f2fs_sync_inode_meta
                                        - f2fs_unlock_all
                                        - sync_inode_metadata
 - f2fs_lock_op
                                         - f2fs_write_inode
                                          - update_inode_page
                                           - get_node_page
                                             return -ENOENT
 - new_inode_page
  - fill_node_footer
 - f2fs_mark_inode_dirty_sync
 - ...
 - f2fs_unlock_op
                                          - f2fs_inode_synced
                                       - f2fs_lock_all
                                       - do_checkpoint

In this checkpoint, we can get an inode page which contains zeros having valid
node footer only.

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

fs/f2fs/inode.c

@@ -316,7 +316,6 @@ retry:
 		} else if (err != -ENOENT) {
 			f2fs_stop_checkpoint(sbi, false);
 		}
-		f2fs_inode_synced(inode);
 		return 0;
 	}
 	ret = update_inode(inode, node_page);
@@ -450,6 +449,7 @@ void handle_failed_inode(struct inode *inode)
 	 * in a panic when flushing dirty inodes in gdirty_list.
 	 */
 	update_inode_page(inode);
+	f2fs_inode_synced(inode);
 
 	/* don't make bad inode, since it becomes a regular file. */
 	unlock_new_inode(inode);

fs/f2fs/namei.c

@@ -148,8 +148,6 @@ static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	inode->i_mapping->a_ops = &f2fs_dblock_aops;
 	ino = inode->i_ino;
 
-	f2fs_balance_fs(sbi, true);
-
 	f2fs_lock_op(sbi);
 	err = f2fs_add_link(dentry, inode);
 	if (err)
@@ -163,6 +161,8 @@ static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 
 	if (IS_DIRSYNC(dir))
 		f2fs_sync_fs(sbi->sb, 1);
+
+	f2fs_balance_fs(sbi, true);
 	return 0;
 out:
 	handle_failed_inode(inode);
@@ -423,8 +423,6 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &f2fs_dblock_aops;
 
-	f2fs_balance_fs(sbi, true);
-
 	f2fs_lock_op(sbi);
 	err = f2fs_add_link(dentry, inode);
 	if (err)
@@ -487,6 +485,8 @@ err_out:
 	}
 
 	kfree(sd);
+
+	f2fs_balance_fs(sbi, true);
 	return err;
 out:
 	handle_failed_inode(inode);
@@ -508,8 +508,6 @@ static int f2fs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	inode->i_mapping->a_ops = &f2fs_dblock_aops;
 	mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_HIGH_ZERO);
 
-	f2fs_balance_fs(sbi, true);
-
 	set_inode_flag(inode, FI_INC_LINK);
 	f2fs_lock_op(sbi);
 	err = f2fs_add_link(dentry, inode);
@@ -524,6 +522,8 @@ static int f2fs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 
 	if (IS_DIRSYNC(dir))
 		f2fs_sync_fs(sbi->sb, 1);
+
+	f2fs_balance_fs(sbi, true);
 	return 0;
 
 out_fail:
@@ -554,8 +554,6 @@ static int f2fs_mknod(struct inode *dir, struct dentry *dentry,
 	init_special_inode(inode, inode->i_mode, rdev);
 	inode->i_op = &f2fs_special_inode_operations;
 
-	f2fs_balance_fs(sbi, true);
-
 	f2fs_lock_op(sbi);
 	err = f2fs_add_link(dentry, inode);
 	if (err)
@@ -569,6 +567,8 @@ static int f2fs_mknod(struct inode *dir, struct dentry *dentry,
 
 	if (IS_DIRSYNC(dir))
 		f2fs_sync_fs(sbi->sb, 1);
+
+	f2fs_balance_fs(sbi, true);
 	return 0;
 out:
 	handle_failed_inode(inode);
@@ -595,8 +595,6 @@ static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry,
 		inode->i_mapping->a_ops = &f2fs_dblock_aops;
 	}
 
-	f2fs_balance_fs(sbi, true);
-
 	f2fs_lock_op(sbi);
 	err = acquire_orphan_inode(sbi);
 	if (err)
@@ -622,6 +620,8 @@ static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry,
 	/* link_count was changed by d_tmpfile as well. */
 	f2fs_unlock_op(sbi);
 	unlock_new_inode(inode);
+
+	f2fs_balance_fs(sbi, true);
 	return 0;
 
 release_out: