Re: [f2fs-dev] Space leak in f2fs

[Jaegeuk Kim <jaegeuk@kernel.org>]

Hi Chao,

On Fri, May 15, 2015 at 04:31:43PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 

[snip]

> > +	/* if orphan inode, we don't need to write its data */
> > +	if (is_orphan_inode(sbi, inode->i_ino))
> > +		goto out;
> 
> When user create a temp file by invoking open with O_TMPFILE flag,
> in ->tmpfile our temp file will be added into orphan list as its
> nlink is zero.
> 
> If we skip writting out data for this orphan inode, later, even though
> we add nlink/directory entry for orphan inode by calling linkat,
> our file will contain inconsistent data between in-memory and on-disk.
> 
> So how about considering for this case?

Right.
How about the below patch?

> 
> BTW, the previous fixing patch looks good to me.

But, my new concern here is a memory pressure. If we do not drop the inode
when iput was called, we need to wait for another time slot to reclaim its
memory.

Thanks,

---
 fs/f2fs/checkpoint.c | 19 +++++++++++++++++++
 fs/f2fs/data.c       |  8 ++++++++
 fs/f2fs/dir.c        |  1 +
 fs/f2fs/f2fs.h       |  2 ++
 fs/f2fs/super.c      | 14 +++++++++++++-
 5 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 7b7a9d8..74875fb 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -378,6 +378,20 @@ static void __remove_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)
 	spin_unlock(&im->ino_lock);
 }
 
+static bool __exist_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)
+{
+	struct inode_management *im = &sbi->im[type];
+	struct ino_entry *e;
+	bool exist = false;
+
+	spin_lock(&im->ino_lock);
+	e = radix_tree_lookup(&im->ino_root, ino);
+	if (e)
+		exist = true;
+	spin_unlock(&im->ino_lock);
+	return exist;
+}
+
 void add_dirty_inode(struct f2fs_sb_info *sbi, nid_t ino, int type)
 {
 	/* add new dirty ino entry into list */
@@ -458,6 +472,11 @@ void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
 	__remove_ino_entry(sbi, ino, ORPHAN_INO);
 }
 
+bool is_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
+{
+	return __exist_ino_entry(sbi, ino, ORPHAN_INO);
+}
+
 static void recover_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
 {
 	struct inode *inode = f2fs_iget(sbi->sb, ino);
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b0cc2aa..d883c14 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1749,6 +1749,14 @@ write:
 		goto out;
 	}
 
+	/*
+	 * if orphan inode, we don't need to write its data,
+	 * but, tmpfile is not the case.
+	 */
+	if (is_orphan_inode(sbi, inode->i_ino) &&
+			!is_inode_flag_set(F2FS_I(inode), FI_TMP_INODE))
+		goto out;
+
 	if (!wbc->for_reclaim)
 		need_balance_fs = true;
 	else if (has_not_enough_free_secs(sbi, 0))
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 3e92376..a2ea1b9 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -648,6 +648,7 @@ int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
 	update_inode(inode, page);
 	f2fs_put_page(page, 1);
 
+	set_inode_flag(F2FS_I(inode), FI_TMP_INODE);
 	clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
 fail:
 	up_write(&F2FS_I(inode)->i_sem);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index cdcae06..de21d38 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1337,6 +1337,7 @@ static inline void f2fs_change_bit(unsigned int nr, char *addr)
 /* used for f2fs_inode_info->flags */
 enum {
 	FI_NEW_INODE,		/* indicate newly allocated inode */
+	FI_TMP_INODE,		/* indicate tmpfile */
 	FI_DIRTY_INODE,		/* indicate inode is dirty or not */
 	FI_DIRTY_DIR,		/* indicate directory has dirty pages */
 	FI_INC_LINK,		/* need to increment i_nlink */
@@ -1726,6 +1727,7 @@ int acquire_orphan_inode(struct f2fs_sb_info *);
 void release_orphan_inode(struct f2fs_sb_info *);
 void add_orphan_inode(struct f2fs_sb_info *, nid_t);
 void remove_orphan_inode(struct f2fs_sb_info *, nid_t);
+bool is_orphan_inode(struct f2fs_sb_info *, nid_t);
 void recover_orphan_inodes(struct f2fs_sb_info *);
 int get_valid_checkpoint(struct f2fs_sb_info *);
 void update_dirty_page(struct inode *, struct page *);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 7464d08..98af3bf 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -430,9 +430,21 @@ static int f2fs_drop_inode(struct inode *inode)
 	 *  - f2fs_write_data_page
 	 *    - f2fs_gc -> iput -> evict
 	 *       - inode_wait_for_writeback(inode)
+	 * In order to avoid that, f2fs_write_data_page does not write data
+	 * pages for orphan inode except tmpfile.
+	 * Nevertheless, we need to truncate the tmpfile's data to avoid
+	 * needless cleaning.
 	 */
-	if (!inode_unhashed(inode) && inode->i_state & I_SYNC)
+	if (is_inode_flag_set(F2FS_I(inode), FI_TMP_INODE) &&
+						inode->i_state & I_SYNC) {
+		spin_unlock(&inode->i_lock);
+		i_size_write(inode, 0);
+
+		if (F2FS_HAS_BLOCKS(inode))
+			f2fs_truncate(inode);
+		spin_lock(&inode->i_lock);
 		return 0;
+	}
 	return generic_drop_inode(inode);
 }
 
-- 
2.1.1