ext4: fix readdir error in the case of inline_data+dir_index

Zach reported a problem that if inline data is enabled, we don't
tell the difference between the offset of '.' and '..'. And a
getdents will fail if the user only want to get '.' and what's worse,
if there is a conversion happens when the user calls getdents
many times, he/she may get the same entry twice.

In theory, a dir block would also fail if it is converted to a
hashed-index based dir since f_pos will become a hash value, not the
real one, but it doesn't happen.  And a deep investigation shows that
we uses a hash based solution even for a normal dir if the dir_index
feature is enabled.

So this patch just adds a new htree_inlinedir_to_tree for inline dir,
and if we find that the hash index is supported, we will do like what
we do for a dir block.

Reported-by: Zach Brown <zab@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 11 insertions, 18 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 955c907fc980..6653fc35ecb7 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -972,6 +972,17 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
                         hinfo.hash_version +=
                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+                if (ext4_has_inline_data(dir)) {
+                        int has_inline_data = 1;
+                        count = htree_inlinedir_to_tree(dir_file, dir, 0,
+                                                        &hinfo, start_hash,
+                                                        start_minor_hash,
+                                                        &has_inline_data);
+                        if (has_inline_data) {
+                                *next_hash = ~0;
+                                return count;
+                        }
+                }
                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
                                                start_hash, start_minor_hash);
                 *next_hash = ~0;
@@ -1456,24 +1467,6 @@ struct dentry *ext4_get_parent(struct dentry *child)
         return d_obtain_alias(ext4_iget(child->d_inode->i_sb, ino));
 }
 
-#define S_SHIFT 12
-static unsigned char ext4_type_by_mode[S_IFMT >> S_SHIFT] = {
-        [S_IFREG >> S_SHIFT]    = EXT4_FT_REG_FILE,
-        [S_IFDIR >> S_SHIFT]    = EXT4_FT_DIR,
-        [S_IFCHR >> S_SHIFT]    = EXT4_FT_CHRDEV,
-        [S_IFBLK >> S_SHIFT]    = EXT4_FT_BLKDEV,
-        [S_IFIFO >> S_SHIFT]    = EXT4_FT_FIFO,
-        [S_IFSOCK >> S_SHIFT]   = EXT4_FT_SOCK,
-        [S_IFLNK >> S_SHIFT]    = EXT4_FT_SYMLINK,
-};
-
-static inline void ext4_set_de_type(struct super_block *sb,
-                                struct ext4_dir_entry_2 *de,
-                                umode_t mode) {
-        if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE))
-                de->file_type = ext4_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
-}
-
 /*
  * Move count entries from end of map between two memory locations.
  * Returns pointer to last entry moved.