f2fs: fix tracking parent inode number

Previously, f2fs didn't track the parent inode number correctly which is stored
in each f2fs_inode. In the case of the following scenario, a bug can be occured.

Let's suppose there are one directory, "/b", and two files, "/a" and "/b/a".
 - pino of "/a" is ROOT_INO.
 - pino of "/b/a" is DIR_B_INO.

Then,
 # sync
  : The inode pages of "/a" and "/b/a" contain the parent inode numbers as
    ROOT_INO and DIR_B_INO respectively.
 # mv /a /b/a
  : The parent inode number of "/a" should be changed to DIR_B_INO, but f2fs
    didn't do that. Ref. f2fs_set_link().

In order to fix this clearly, I added i_pino in f2fs_inode_info, and whenever
it needs to be changed like in f2fs_add_link() and f2fs_set_link(), it is
updated temporarily in f2fs_inode_info.

And later, f2fs_write_inode() stores the latest information to the inode pages.
For power-off-recovery, f2fs_sync_file() triggers simply f2fs_write_inode().

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index aa4ef4f48ffd..df5fb381ebf1 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -107,6 +107,7 @@ static int do_read_inode(struct inode *inode)
         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);
         f2fs_put_page(node_page, 1);
         return 0;
@@ -200,6 +201,7 @@ void update_inode(struct inode *inode, struct page *node_page)
         ri->i_current_depth = cpu_to_le32(F2FS_I(inode)->i_current_depth);
         ri->i_xattr_nid = cpu_to_le32(F2FS_I(inode)->i_xattr_nid);
         ri->i_flags = cpu_to_le32(F2FS_I(inode)->i_flags);
+        ri->i_pino = cpu_to_le32(F2FS_I(inode)->i_pino);
         ri->i_generation = cpu_to_le32(inode->i_generation);
         set_page_dirty(node_page);
 }