f2fs: fix handling errors got by f2fs_write_inode

Ruslan reported that f2fs hangs with an infinite loop in f2fs_sync_file():

	while (sync_node_pages(sbi, inode->i_ino, &wbc) == 0)
		f2fs_write_inode(inode, NULL);

The reason was revealed that the cold flag is not set even thought this inode is
a normal file. Therefore, sync_node_pages() skips to write node blocks since it
only writes cold node blocks.

The cold flag is stored to the node_footer in node block, and whenever a new
node page is allocated, it is set according to its file type, file or directory.

But, after sudden-power-off, when recovering the inode page, f2fs doesn't recover
its cold flag.

So, let's assign the cold flag in more right places.

One more thing:
If f2fs_write_inode() returns an error due to whatever situations, there would
be no dirty node pages so that sync_node_pages() returns zero.
(i.e., zero means nothing was written.)

Reported-by: Ruslan N. Marchenko <me@ruff.mobi>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f9e085dfb1f0..7f9ea9271ebe 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -160,15 +160,17 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
         if (need_to_sync_dir(sbi, inode))
                 need_cp = true;
 
-        f2fs_write_inode(inode, NULL);
-
         if (need_cp) {
                 /* all the dirty node pages should be flushed for POR */
                 ret = f2fs_sync_fs(inode->i_sb, 1);
                 clear_inode_flag(F2FS_I(inode), FI_NEED_CP);
         } else {
-                while (sync_node_pages(sbi, inode->i_ino, &wbc) == 0)
-                        f2fs_write_inode(inode, NULL);
+                /* if there is no written node page, write its inode page */
+                while (!sync_node_pages(sbi, inode->i_ino, &wbc)) {
+                        ret = f2fs_write_inode(inode, NULL);
+                        if (ret)
+                                goto out;
+                }
                 filemap_fdatawait_range(sbi->node_inode->i_mapping,
                                                         0, LONG_MAX);
         }