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

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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>
This commit is contained in:
Tao Ma
2013-04-19 17:53:09 -04:00
committed by Theodore Ts'o
parent 28daf4fae8
commit 8af0f08227
4 changed files with 153 additions and 28 deletions
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20
fs/ext4/dir.c
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@@ -46,7 +46,8 @@ static int is_dx_dir(struct inode *inode)
if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
EXT4_FEATURE_COMPAT_DIR_INDEX) &&
((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
((inode->i_size >> sb->s_blocksize_bits) == 1)))
((inode->i_size >> sb->s_blocksize_bits) == 1) ||
ext4_has_inline_data(inode)))
return 1;
return 0;
@@ -115,14 +116,6 @@ static int ext4_readdir(struct file *filp,
int ret = 0;
int dir_has_error = 0;
if (ext4_has_inline_data(inode)) {
int has_inline_data = 1;
ret = ext4_read_inline_dir(filp, dirent, filldir,
&has_inline_data);
if (has_inline_data)
return ret;
}
if (is_dx_dir(inode)) {
err = ext4_dx_readdir(filp, dirent, filldir);
if (err != ERR_BAD_DX_DIR) {
@@ -136,6 +129,15 @@ static int ext4_readdir(struct file *filp,
ext4_clear_inode_flag(file_inode(filp),
EXT4_INODE_INDEX);
}
if (ext4_has_inline_data(inode)) {
int has_inline_data = 1;
ret = ext4_read_inline_dir(filp, dirent, filldir,
&has_inline_data);
if (has_inline_data)
return ret;
}
stored = 0;
offset = filp->f_pos & (sb->s_blocksize - 1);