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>
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index c0fd1a1..abf8b627 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -19,7 +19,8 @@
#define EXT4_XATTR_SYSTEM_DATA "data"
#define EXT4_MIN_INLINE_DATA_SIZE ((sizeof(__le32) * EXT4_N_BLOCKS))
-#define EXT4_INLINE_DOTDOT_SIZE 4
+#define EXT4_INLINE_DOTDOT_OFFSET 2
+#define EXT4_INLINE_DOTDOT_SIZE 4
int ext4_get_inline_size(struct inode *inode)
{
@@ -1289,6 +1290,112 @@
return ret;
}
+/*
+ * This function fills a red-black tree with information from an
+ * inlined dir. It returns the number directory entries loaded
+ * into the tree. If there is an error it is returned in err.
+ */
+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)
+{
+ int err = 0, count = 0;
+ unsigned int parent_ino;
+ int pos;
+ struct ext4_dir_entry_2 *de;
+ struct inode *inode = file_inode(dir_file);
+ int ret, inline_size = 0;
+ struct ext4_iloc iloc;
+ void *dir_buf = NULL;
+ struct ext4_dir_entry_2 fake;
+
+ ret = ext4_get_inode_loc(inode, &iloc);
+ if (ret)
+ return ret;
+
+ down_read(&EXT4_I(inode)->xattr_sem);
+ if (!ext4_has_inline_data(inode)) {
+ up_read(&EXT4_I(inode)->xattr_sem);
+ *has_inline_data = 0;
+ goto out;
+ }
+
+ inline_size = ext4_get_inline_size(inode);
+ dir_buf = kmalloc(inline_size, GFP_NOFS);
+ if (!dir_buf) {
+ ret = -ENOMEM;
+ up_read(&EXT4_I(inode)->xattr_sem);
+ goto out;
+ }
+
+ ret = ext4_read_inline_data(inode, dir_buf, inline_size, &iloc);
+ up_read(&EXT4_I(inode)->xattr_sem);
+ if (ret < 0)
+ goto out;
+
+ pos = 0;
+ parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);
+ while (pos < inline_size) {
+ /*
+ * As inlined dir doesn't store any information about '.' and
+ * only the inode number of '..' is stored, we have to handle
+ * them differently.
+ */
+ if (pos == 0) {
+ fake.inode = cpu_to_le32(inode->i_ino);
+ fake.name_len = 1;
+ strcpy(fake.name, ".");
+ fake.rec_len = ext4_rec_len_to_disk(
+ EXT4_DIR_REC_LEN(fake.name_len),
+ inline_size);
+ ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
+ de = &fake;
+ pos = EXT4_INLINE_DOTDOT_OFFSET;
+ } else if (pos == EXT4_INLINE_DOTDOT_OFFSET) {
+ fake.inode = cpu_to_le32(parent_ino);
+ fake.name_len = 2;
+ strcpy(fake.name, "..");
+ fake.rec_len = ext4_rec_len_to_disk(
+ EXT4_DIR_REC_LEN(fake.name_len),
+ inline_size);
+ ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
+ de = &fake;
+ pos = EXT4_INLINE_DOTDOT_SIZE;
+ } else {
+ de = (struct ext4_dir_entry_2 *)(dir_buf + pos);
+ pos += ext4_rec_len_from_disk(de->rec_len, inline_size);
+ if (ext4_check_dir_entry(inode, dir_file, de,
+ iloc.bh, dir_buf,
+ inline_size, pos)) {
+ ret = count;
+ goto out;
+ }
+ }
+
+ ext4fs_dirhash(de->name, de->name_len, hinfo);
+ if ((hinfo->hash < start_hash) ||
+ ((hinfo->hash == start_hash) &&
+ (hinfo->minor_hash < start_minor_hash)))
+ continue;
+ if (de->inode == 0)
+ continue;
+ err = ext4_htree_store_dirent(dir_file,
+ hinfo->hash, hinfo->minor_hash, de);
+ if (err) {
+ count = err;
+ goto out;
+ }
+ count++;
+ }
+ ret = count;
+out:
+ kfree(dir_buf);
+ brelse(iloc.bh);
+ return ret;
+}
+
int ext4_read_inline_dir(struct file *filp,
void *dirent, filldir_t filldir,
int *has_inline_data)