2009-02-10 22:59:58

by Andrew Morton

[permalink] [raw]
Subject: + ext3-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesystems.patch added to -mm tree


The patch titled
ext3: fix support for empty directory blocks in 64k blocksize filesystems
has been added to the -mm tree. Its filename is
ext3-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesystems.patch

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------------------------------------------------------
Subject: ext3: fix support for empty directory blocks in 64k blocksize filesystems
From: Wei Yongjun <[email protected]>

The rec_len field in the directory entry is 16 bits, so if the filesystem
is completely empty, rec_len of 0 is used to designate 65536 in e2fsprogs,
for the case where the directory entry takes the entire 64k block.

But if an empty directory is read, an error message will be output by
current kernels. You can use the following commands to reproduce it.

- mkfs.ext3 -b $(( 64 * 1024 )) /dev/sdc1
- mount /dev/sda1 /mnt
- cd /mnt/lost+found
- ll
- tail /var/log/messages
EXT3-fs error (device sdc1): ext3_readdir: bad entry in \
directory #11: rec_len is smaller than minimal - offset=0, \
inode=0, rec_len=0, name_len=0

Treat a rec_len of 0 as 65536, as e2fsprogs does.

Signed-off-by: Wei Yongjun <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

include/linux/ext3_fs.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff -puN include/linux/ext3_fs.h~ext3-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesystems include/linux/ext3_fs.h
--- a/include/linux/ext3_fs.h~ext3-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesystems
+++ a/include/linux/ext3_fs.h
@@ -711,7 +711,7 @@ static inline unsigned ext3_rec_len_from
{
unsigned len = le16_to_cpu(dlen);

- if (len == EXT3_MAX_REC_LEN)
+ if (len == EXT3_MAX_REC_LEN || len == 0)
return 1 << 16;
return len;
}
@@ -719,7 +719,7 @@ static inline unsigned ext3_rec_len_from
static inline __le16 ext3_rec_len_to_disk(unsigned len)
{
if (len == (1 << 16))
- return cpu_to_le16(EXT3_MAX_REC_LEN);
+ return cpu_to_le16(0);
else if (len > (1 << 16))
BUG();
return cpu_to_le16(len);
_

Patches currently in -mm which might be from [email protected] are

linux-next.patch
fs-jffs2-mallocc-kmem_cache_alloc-memset-kmem_cache_zalloc.patch
scsi-used-kmem_cache_zalloc-instead-of-kmem_cache_alloc-memset.patch
ext2-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesystems.patch
ext3-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesystems.patch



2009-02-11 15:16:18

by Theodore Ts'o

[permalink] [raw]
Subject: Re: + ext3-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesys tems.patch added to -mm tree

On Tue, Feb 10, 2009 at 02:59:22PM -0800, [email protected] wrote:
>
> The patch titled
> ext3: fix support for empty directory blocks in 64k blocksize filesystems
> has been added to the -mm tree. Its filename is
> ext3-fix-support-for-empty-directory-blocks-in-64k-blocksize-filesystems.patch

NACK; I think we need to discuss this some more. See the discussion
around the similar patch for ext4.

- Ted