f2fs: fix dentry recovery routine

The error scenario is:
1. create /a
(1.a link /a /b)
2. sync
3. unlinke /a
4. create /a
5. fsync /a
6. Sudden power-off

When the f2fs recovers the fsynced dentry, /a, we discover an exsiting dentry at
f2fs_find_entry() in recover_dentry().

In such the case, we should unlink the existing dentry and its inode
and then recover newly created dentry.

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

1 files changed, 19 insertions, 5 deletions

diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 0dd2ce1b492f..539ca32f4483 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -44,9 +44,10 @@ static int recover_dentry(struct page *ipage, struct inode *inode)
         struct f2fs_node *raw_node = (struct f2fs_node *)kaddr;
         struct f2fs_inode *raw_inode = &(raw_node->i);
         nid_t pino = le32_to_cpu(raw_inode->i_pino);
+        struct f2fs_dir_entry *de;
         struct qstr name;
         struct page *page;
-        struct inode *dir;
+        struct inode *dir, *einode;
         int err = 0;
 
         dir = check_dirty_dir_inode(F2FS_SB(inode->i_sb), pino);
@@ -61,13 +62,26 @@ static int recover_dentry(struct page *ipage, struct inode *inode)
 
         name.len = le32_to_cpu(raw_inode->i_namelen);
         name.name = raw_inode->i_name;
-
-        if (f2fs_find_entry(dir, &name, &page)) {
+retry:
+        de = f2fs_find_entry(dir, &name, &page);
+        if (de && inode->i_ino == le32_to_cpu(de->ino)) {
                 kunmap(page);
                 f2fs_put_page(page, 0);
-        } else {
-                err = __f2fs_add_link(dir, &name, inode);
+                goto out;
+        }
+        if (de) {
+                einode = f2fs_iget(inode->i_sb, le32_to_cpu(de->ino));
+                if (IS_ERR(einode)) {
+                        WARN_ON(1);
+                        if (PTR_ERR(einode) == -ENOENT)
+                                err = -EEXIST;
+                        goto out;
+                }
+                f2fs_delete_entry(de, page, einode);
+                iput(einode);
+                goto retry;
         }
+        err = __f2fs_add_link(dir, &name, inode);
 out:
         f2fs_msg(inode->i_sb, KERN_NOTICE, "recover_inode and its dentry: "
                         "ino = %x, name = %s, dir = %lx, err = %d",