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, 23 insertions, 0 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 779d26b7beff..0aabb344b02e 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2518,6 +2518,11 @@ extern int ext4_try_create_inline_dir(handle_t *handle,
 extern int ext4_read_inline_dir(struct file *filp,
 				void *dirent, filldir_t filldir,
 				int *has_inline_data);
+extern int htree_inlinedir_to_tree(struct file *dir_file,
+				   struct inode *dir, ext4_lblk_t block,
+				   struct dx_hash_info *hinfo,
+				   __u32 start_hash, __u32 start_minor_hash,
+				   int *has_inline_data);
 extern struct buffer_head *ext4_find_inline_entry(struct inode *dir,
 					const struct qstr *d_name,
 					struct ext4_dir_entry_2 **res_dir,
@@ -2554,6 +2559,24 @@ extern void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
 extern int ext4_handle_dirty_dirent_node(handle_t *handle,
 					 struct inode *inode,
 					 struct buffer_head *bh);
+#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];
+}
+
 
 /* symlink.c */
 extern const struct inode_operations ext4_symlink_inode_operations;