ext4: Avoid rec_len overflow with 64KB block size
From: Jan Kara [EMAIL PROTECTED]
With 64KB blocksize, a directory entry can have size 64KB which does not fit
into 16 bits we have for entry lenght. So we store 0x instead and convert
value when read from / written to disk. The patch also converts some places
to use ext4_next_entry() when we are changing them anyway.
Signed-off-by: Jan Kara [EMAIL PROTECTED]
Signed-off-by: Mingming Cao [EMAIL PROTECTED]
---
fs/ext4/dir.c | 12 ---
fs/ext4/namei.c | 76 ++-
include/linux/ext4_fs.h | 20
3 files changed, 62 insertions(+), 46 deletions(-)
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 3ab01c0..20b1e28 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -69,7 +69,7 @@ int ext4_check_dir_entry (const char * function, struct inode
* dir,
unsigned long offset)
{
const char * error_msg = NULL;
- const int rlen = le16_to_cpu(de-rec_len);
+ const int rlen = ext4_rec_len_from_disk(de-rec_len);
if (rlen EXT4_DIR_REC_LEN(1))
error_msg = rec_len is smaller than minimal;
@@ -176,10 +176,10 @@ revalidate:
* least that it is non-zero. A
* failure will be detected in the
* dirent test below. */
- if (le16_to_cpu(de-rec_len)
- EXT4_DIR_REC_LEN(1))
+ if (ext4_rec_len_from_disk(de-rec_len)
+EXT4_DIR_REC_LEN(1))
break;
- i += le16_to_cpu(de-rec_len);
+ i += ext4_rec_len_from_disk(de-rec_len);
}
offset = i;
filp-f_pos = (filp-f_pos ~(sb-s_blocksize - 1))
@@ -201,7 +201,7 @@ revalidate:
ret = stored;
goto out;
}
- offset += le16_to_cpu(de-rec_len);
+ offset += ext4_rec_len_from_disk(de-rec_len);
if (le32_to_cpu(de-inode)) {
/* We might block in the next section
* if the data destination is
@@ -223,7 +223,7 @@ revalidate:
goto revalidate;
stored ++;
}
- filp-f_pos += le16_to_cpu(de-rec_len);
+ filp-f_pos += ext4_rec_len_from_disk(de-rec_len);
}
offset = 0;
brelse (bh);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 5fdb862..96e8a85 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -281,7 +281,7 @@ static struct stats dx_show_leaf(struct dx_hash_info
*hinfo, struct ext4_dir_ent
space += EXT4_DIR_REC_LEN(de-name_len);
names++;
}
- de = (struct ext4_dir_entry_2 *) ((char *) de +
le16_to_cpu(de-rec_len));
+ de = ext4_next_entry(de);
}
printk((%i)\n, names);
return (struct stats) { names, space, 1 };
@@ -552,7 +552,8 @@ static int ext4_htree_next_block(struct inode *dir, __u32
hash,
*/
static inline struct ext4_dir_entry_2 *ext4_next_entry(struct ext4_dir_entry_2
*p)
{
- return (struct ext4_dir_entry_2 *)((char*)p + le16_to_cpu(p-rec_len));
+ return (struct ext4_dir_entry_2 *)((char*)p +
+ ext4_rec_len_from_disk(p-rec_len));
}
/*
@@ -721,7 +722,7 @@ static int dx_make_map (struct ext4_dir_entry_2 *de, int
size,
cond_resched();
}
/* XXX: do we need to check rec_len == 0 case? -Chris */
- de = (struct ext4_dir_entry_2 *) ((char *) de +
le16_to_cpu(de-rec_len));
+ de = ext4_next_entry(de);
}
return count;
}
@@ -823,7 +824,7 @@ static inline int search_dirblock(struct buffer_head * bh,
return 1;
}
/* prevent looping on a bad block */
- de_len = le16_to_cpu(de-rec_len);
+ de_len = ext4_rec_len_from_disk(de-rec_len);
if (de_len = 0)
return -1;
offset += de_len;
@@ -1136,7 +1137,7 @@ dx_move_dirents(char *from, char *to, struct dx_map_entry
*map, int count)
rec_len = EXT4_DIR_REC_LEN(de-name_len);
memcpy (to, de, rec_len);
((struct ext4_dir_entry_2 *) to)-rec_len =
- cpu_to_le16(rec_len);
+ ext4_rec_len_to_disk(rec_len);
de-inode = 0;
map++;
to +=
