[U-Boot] [PATCH v2 1/4] fs/ext4: Fix group descriptor checksum calculation

[Tom Rini]

On Tue, Sep 26, 2017 at 07:04:06PM +0300, Tuomas Tynkkynen wrote:
> On 09/26/2017 06:25 PM, Tom Rini wrote:
> >On Mon, Sep 25, 2017 at 10:06:31PM +0300, Tuomas Tynkkynen wrote:
> >>The current code doesn't compute the group descriptor checksum correctly
> >>for the filesystems that e2fsprogs 1.43.4 creates (they have
> >>'Group descriptor size: 64' as reported by tune2fs). Extend the checksum
> >>calculation to be done as ext4_group_desc_csum() does in Linux.
> >>
> >>This fixes these errors in dmesg from running fs-test.sh and makes it
> >>succeed again:
> >>
> >>[1671902.620699] EXT4-fs (loop1): ext4_check_descriptors: Checksum for group 0 failed (35782!=10965)
> >>[1671902.620706] EXT4-fs (loop1): group descriptors corrupted!
> >>
> >>Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen at iki.fi>
> >>---
> >>v2: New patch
> >>---
> >>  fs/ext4/ext4_common.c | 4 ++++
> >>  1 file changed, 4 insertions(+)
> >>
> >>diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
> >>index 621c61e5c7..31952f48b9 100644
> >>--- a/fs/ext4/ext4_common.c
> >>+++ b/fs/ext4/ext4_common.c
> >>@@ -432,6 +432,10 @@ uint16_t ext4fs_checksum_update(uint32_t i)
> >>  		crc = ext2fs_crc16(crc, desc, offset);
> >>  		offset += sizeof(desc->bg_checksum);	/* skip checksum */
> >>  		assert(offset == sizeof(*desc));
> >>+		if (offset < fs->gdsize) {
> >>+			crc = ext2fs_crc16(crc, (__u8 *)desc + offset,
> >>+					   fs->gdsize - offset);
> >>+		}
> >
> >This would be feb0ab32a57e4e6c8b24f6fb68f0ce08efe4603c from the kernel?
> 
> No, it goes further back, to 2007 even(!): 717d50e4971b81b96c0199c91cdf0
> 
> >So shouldn't we have le16_to_cpu on fs->gdsize ?  Or did I read over the
> >'git log -p' output in the kernel too quickly?  Thanks!
> >
> 
> No, because fs->gdsize is already endian-swapped elsewhere:
> 
> >2345                 fs->gdsize = le32_to_cpu(data->sblock.feature_incompat) &
> >2346                         EXT4_FEATURE_INCOMPAT_64BIT ?
> >2347                         le16_to_cpu(data->sblock.descriptor_size) : 32;

Ah, thanks for explaining and confirming.

Reviewed-by; Tom Rini <trini at konsulko.com>

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20170926/a6fd6634/attachment.sig>