f2fs: fix BUG_ON during f2fs_evict_inode(dir)

During the dentry recovery routine, recover_inode() triggers __f2fs_add_link
with its directory inode.

In the following scenario, a bug is captured.
 1. dir = f2fs_iget(pino)
 2. __f2fs_add_link(dir, name)
 3. iput(dir)
  -> f2fs_evict_inode() faces with BUG_ON(atomic_read(fi->dirty_dents))

Kernel BUG at ffffffffa01c0676 [verbose debug info unavailable]
[<ffffffffa01c0676>] f2fs_evict_inode+0x276/0x300 [f2fs]
Call Trace:
 [<ffffffff8118ea00>] evict+0xb0/0x1b0
 [<ffffffff8118f1c5>] iput+0x105/0x190
 [<ffffffffa01d2dac>] recover_fsync_data+0x3bc/0x1070 [f2fs]
 [<ffffffff81692e8a>] ? io_schedule+0xaa/0xd0
 [<ffffffff81690acb>] ? __wait_on_bit_lock+0x7b/0xc0
 [<ffffffff8111a0e7>] ? __lock_page+0x67/0x70
 [<ffffffff81165e21>] ? kmem_cache_alloc+0x31/0x140
 [<ffffffff8118a502>] ? __d_instantiate+0x92/0xf0
 [<ffffffff812a949b>] ? security_d_instantiate+0x1b/0x30
 [<ffffffff8118a5b4>] ? d_instantiate+0x54/0x70

This means that we should flush all the dentry pages between iget and iput().
But, during the recovery routine, it is unallowed due to consistency, so we
have to wait the whole recovery process.
And then, write_checkpoint flushes all the dirty dentry blocks, and nicely we
can put the stale dir inodes from the dirty_dir_inode_list.

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

1 files changed, 9 insertions, 5 deletions

diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 4d895149a6f0..23f580397e6c 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -42,6 +42,7 @@ static int recover_dentry(struct page *ipage, struct inode *inode)
 {
 	struct f2fs_node *raw_node = (struct f2fs_node *)kmap(ipage);
 	struct f2fs_inode *raw_inode = &(raw_node->i);
+	nid_t pino = le32_to_cpu(raw_inode->i_pino);
 	struct qstr name;
 	struct f2fs_dir_entry *de;
 	struct page *page;
@@ -51,10 +52,14 @@ static int recover_dentry(struct page *ipage, struct inode *inode)
 	if (!is_dent_dnode(ipage))
 		goto out;
 
-	dir = f2fs_iget(inode->i_sb, le32_to_cpu(raw_inode->i_pino));
-	if (IS_ERR(dir)) {
-		err = PTR_ERR(dir);
-		goto out;
+	dir = check_dirty_dir_inode(F2FS_SB(inode->i_sb), pino);
+	if (!dir) {
+		dir = f2fs_iget(inode->i_sb, pino);
+		if (IS_ERR(dir)) {
+			err = PTR_ERR(dir);
+			goto out;
+		}
+		set_inode_flag(F2FS_I(dir), FI_DELAY_IPUT);
 	}
 
 	name.len = le32_to_cpu(raw_inode->i_namelen);
@@ -67,7 +72,6 @@ static int recover_dentry(struct page *ipage, struct inode *inode)
 	} else {
 		err = __f2fs_add_link(dir, &name, inode);
 	}
-	iput(dir);
 out:
 	kunmap(ipage);
 	return err;