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authorWei Yongjun <yjwei@cn.fujitsu.com>2009-02-10 09:53:42 -0500
committerTheodore Tso <tytso@mit.edu>2009-02-10 09:53:42 -0500
commit7be2baaa0322c59ba888aa5260a8c130666acd41 (patch)
treea1543a38923d60092e06741ab3dee9ce9af32abc
parent7f5aa215088b817add9c71914b83650bdd49f8a9 (diff)
ext4: Fix to read empty directory blocks correctly in 64k
The rec_len field in the directory entry is 16 bits, so there was a problem representing rec_len for filesystems with a 64k block size in the case where the directory entry takes the entire 64k block. Unfortunately, there were two schemes that were proposed; one where all zeros meant 65536 and one where all ones (65535) meant 65536. E2fsprogs used 0, whereas the kernel used 65535. Oops. Fortunately this case happens extremely rarely, with the most common case being the lost+found directory, created by mke2fs. So we will be liberal in what we accept, and accept both encodings, but we will continue to encode 65536 as 65535. This will require a change in e2fsprogs, but with fortunately ext4 filesystems normally have the dir_index feature enabled, which precludes having a completely empty directory block. Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/ext4.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index aafc9eba1c2..b0c87dce66a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -868,7 +868,7 @@ static inline unsigned ext4_rec_len_from_disk(__le16 dlen)
{
unsigned len = le16_to_cpu(dlen);
- if (len == EXT4_MAX_REC_LEN)
+ if (len == EXT4_MAX_REC_LEN || len == 0)
return 1 << 16;
return len;
}