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ext4: fix readdir error in case 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, we may meet with duplicate dir entries as the offset
for inline dir and non-inline one is quite different.

This patch just try to resolve this problem if dir_index
is disabled. In this case, f_pos is the real offset with
the dir block, so for inline dir, we just pretend as if
we are a dir block and returns the offset like a norml
dir block does.

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>
wifi-calibration
Tao Ma 2013-04-19 17:55:33 -04:00 committed by Theodore Ts'o
parent 8af0f08227
commit c4d8b0235a
1 changed files with 51 additions and 18 deletions
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69
fs/ext4/inline.c
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@ -1396,6 +1396,14 @@ out:
return ret;
}
/*
* So this function is called when the volume is mkfsed with
* dir_index disabled. In order to keep f_pos persistent
* after we convert from an inlined dir to a blocked based,
* we just pretend that we are a normal dir and return the
* offset as if '.' and '..' really take place.
*
*/
int ext4_read_inline_dir(struct file *filp,
void *dirent, filldir_t filldir,
int *has_inline_data)
@ -1409,6 +1417,7 @@ int ext4_read_inline_dir(struct file *filp,
int ret, inline_size = 0;
struct ext4_iloc iloc;
void *dir_buf = NULL;
int dotdot_offset, dotdot_size, extra_offset, extra_size;
ret = ext4_get_inode_loc(inode, &iloc);
if (ret)
@ -1437,8 +1446,21 @@ int ext4_read_inline_dir(struct file *filp,
sb = inode->i_sb;
stored = 0;
parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);
offset = filp->f_pos;
while (!error && !stored && filp->f_pos < inode->i_size) {
/*
* dotdot_offset and dotdot_size is the real offset and
* size for ".." and "." if the dir is block based while
* the real size for them are only EXT4_INLINE_DOTDOT_SIZE.
* So we will use extra_offset and extra_size to indicate them
* during the inline dir iteration.
*/
dotdot_offset = EXT4_DIR_REC_LEN(1);
dotdot_size = dotdot_offset + EXT4_DIR_REC_LEN(2);
extra_offset = dotdot_size - EXT4_INLINE_DOTDOT_SIZE;
extra_size = extra_offset + inline_size;
while (!error && !stored && filp->f_pos < extra_size) {
revalidate:
/*
* If the version has changed since the last call to
@ -1447,15 +1469,23 @@ revalidate:
* dir to make sure.
*/
if (filp->f_version != inode->i_version) {
for (i = 0;
i < inode->i_size && i < offset;) {
for (i = 0; i < extra_size && i < offset;) {
/*
* "." is with offset 0 and
* ".." is dotdot_offset.
*/
if (!i) {
/* skip "." and ".." if needed. */
i += EXT4_INLINE_DOTDOT_SIZE;
i = dotdot_offset;
continue;
} else if (i == dotdot_offset) {
i = dotdot_size;
continue;
}
/* for other entry, the real offset in
* the buf has to be tuned accordingly.
*/
de = (struct ext4_dir_entry_2 *)
(dir_buf + i);
(dir_buf + i - extra_offset);
/* It's too expensive to do a full
* dirent test each time round this
* loop, but we do have to test at
@ -1463,43 +1493,47 @@ revalidate:
* failure will be detected in the
* dirent test below. */
if (ext4_rec_len_from_disk(de->rec_len,
inline_size) < EXT4_DIR_REC_LEN(1))
extra_size) < EXT4_DIR_REC_LEN(1))
break;
i += ext4_rec_len_from_disk(de->rec_len,
inline_size);
extra_size);
}
offset = i;
filp->f_pos = offset;
filp->f_version = inode->i_version;
}
while (!error && filp->f_pos < inode->i_size) {
while (!error && filp->f_pos < extra_size) {
if (filp->f_pos == 0) {
error = filldir(dirent, ".", 1, 0, inode->i_ino,
DT_DIR);
if (error)
break;
stored++;
filp->f_pos = dotdot_offset;
continue;
}
error = filldir(dirent, "..", 2, 0, parent_ino,
DT_DIR);
if (filp->f_pos == dotdot_offset) {
error = filldir(dirent, "..", 2,
dotdot_offset,
parent_ino, DT_DIR);
if (error)
break;
stored++;
filp->f_pos = offset = EXT4_INLINE_DOTDOT_SIZE;
filp->f_pos = dotdot_size;
continue;
}
de = (struct ext4_dir_entry_2 *)(dir_buf + offset);
de = (struct ext4_dir_entry_2 *)
(dir_buf + filp->f_pos - extra_offset);
if (ext4_check_dir_entry(inode, filp, de,
iloc.bh, dir_buf,
inline_size, offset)) {
extra_size, filp->f_pos)) {
ret = stored;
goto out;
}
offset += ext4_rec_len_from_disk(de->rec_len,
inline_size);
if (le32_to_cpu(de->inode)) {
/* We might block in the next section
* if the data destination is
@ -1522,9 +1556,8 @@ revalidate:
stored++;
}
filp->f_pos += ext4_rec_len_from_disk(de->rec_len,
inline_size);
extra_size);
}
offset = 0;
}
out:
kfree(dir_buf);