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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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109
fs/ext4/inline.c
View File

@@ -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 @@ out:
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)