Since find_dentry doesn't lock its dentry page, it can traverse intermediate
bit positions consisting of a big dentry.
For these bit positions, this patch fills the intermediate name length fields
as zeros and skips them during look-up.

Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
 fs/f2fs/dir.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index a34ebd8..71195f5 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -141,11 +141,15 @@ struct f2fs_dir_entry *find_target_dentry(struct 
f2fs_filename *fname,
                        *max_slots = max_len;
                max_len = 0;
 
-               /* remain bug on condition */
-               if (unlikely(!de->name_len))
-                       d->max = -1;
-
-               bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
+               /*
+                * While a large dentry is adding, it can traverse its valid bit
+                * positions, since find_entry does not lock its dentry page.
+                * In that case, let's skip the bit position.
+                */
+               if (de_name.len == 0)
+                       bit_pos++;
+               else
+                       bit_pos += GET_DENTRY_SLOTS(de_name.len);
        }
 
        de = NULL;
@@ -505,8 +509,12 @@ void f2fs_update_dentry(nid_t ino, umode_t mode, struct 
f2fs_dentry_ptr *d,
        memcpy(d->filename[bit_pos], name->name, name->len);
        de->ino = cpu_to_le32(ino);
        set_de_type(de, mode);
-       for (i = 0; i < slots; i++)
+       for (i = 0; i < slots; i++) {
+               /* fill zeros for intermediate name_len slots */
+               if (i >= 1)
+                       d->dentry[bit_pos + i].name_len = 0;
                test_and_set_bit_le(bit_pos + i, (void *)d->bitmap);
+       }
 }
 
 /*
-- 
2.1.1


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