diff options
| author | Tao Ma <boyu.mt@taobao.com> | 2012-07-09 16:29:27 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-09 08:23:13 -0700 |
| commit | 5b8fb491fae20415d04323c34109cd9fcfa28f15 (patch) | |
| tree | ec4d0a294db9d2a2fa673ba51b17da58285bc23b | |
| parent | 3fc50cb8a1117a2591f05be284e85432d6c234c1 (diff) | |
ext4: use s_csum_seed instead of i_csum_seed for xattr block
commit 41eb70dde42b2360074a559a6f1fc49860a50179 upstream.
In xattr block operation, we use h_refcount to indicate whether the
xattr block is shared among many inodes. And xattr block csum uses
s_csum_seed if it is shared and i_csum_seed if it belongs to
one inode. But this has a problem. So consider the block is shared
first bewteen inode A and B, and B has some xattr update and CoW
the xattr block. When it updates the *old* xattr block(because
of the h_refcount change) and calls ext4_xattr_release_block, we
has no idea that inode A is the real owner of the *old* xattr
block and we can't use the i_csum_seed of inode A either in xattr
block csum calculation. And I don't think we have an easy way to
find inode A.
So this patch just removes the tricky i_csum_seed and we now uses
s_csum_seed every time for the xattr block csum. The corresponding
patch for the e2fsprogs will be sent in another patch.
This is spotted by xfstests 117.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/ext4/xattr.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index e56c9ed7d6e3..2cdb98d62980 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -127,19 +127,16 @@ static __le32 ext4_xattr_block_csum(struct inode *inode, struct ext4_xattr_header *hdr) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); - struct ext4_inode_info *ei = EXT4_I(inode); __u32 csum, old; old = hdr->h_checksum; hdr->h_checksum = 0; - if (le32_to_cpu(hdr->h_refcount) != 1) { - block_nr = cpu_to_le64(block_nr); - csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&block_nr, - sizeof(block_nr)); - } else - csum = ei->i_csum_seed; + block_nr = cpu_to_le64(block_nr); + csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&block_nr, + sizeof(block_nr)); csum = ext4_chksum(sbi, csum, (__u8 *)hdr, EXT4_BLOCK_SIZE(inode->i_sb)); + hdr->h_checksum = old; return cpu_to_le32(csum); } |