On 6/20/12 3:40 PM, Eric Sandeen wrote:
> Extent records which should have been printed as:
>
> a.bmx[0] = [startoff,startblock,blockcount,extentflag] 0:[0,12,17,0]
>
> for example, were instead being printed as:
>
> a.bmx[0] = [startoff,startblock,blockcount,extentflag] 0:[0,12884910592,0,0]
>
> in xfs_db. It was simply mis-parsing the extent records due to wrong
> #defines for big-endian machines.
>
> It's been broken since at least xfsprogs-2.6.13, causing xfstests 021
> to fail.
Ping on this one? I'd like to get 021 passing on big-endian. Do I need to
do more due diligence on the correctness of it?
addr_f
(*adf)(iocur_top->data, tfl->offset, next);
fa_cfsblock(obj, bit, next);
bno = (xfs_dfsbno_t)getbitval(obj, bit, BMBT_STARTBLOCK_BITLEN,
BVUNSIGNED);
fa_cfsblock is getting the wrong "bit" passed to it due to the offset in this structure
being wrong, because of the defines in question.
const field_t bmapbta_rec_flds[] = {
{ "startoff", FLDT_CFILEOFFA, OI(BMBT_STARTOFF_BITOFF), C1, 0,
TYP_ATTR },
{ "startblock", FLDT_CFSBLOCK, OI(BMBT_STARTBLOCK_BITOFF), C1, 0,
TYP_ATTR },
...
So we pass it an opaque "obj", and the bit offset into the on-disk inode for the extent
data is the same whether we are on big endian or little endian - I think that is the
issue here.
getbitval() itself handles endian converions once we get to the right data. We just need
the proper offsets to it...
Thanks,
-Eric
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
>
> Why this works is, um ...left as an exercise to the reviewer for now ;)
> TBH I get lost in xfs_db, and I'm not sure how endianness is handled,
> but it's pretty clearly not like this!
>
> diff --git a/db/btblock.c b/db/btblock.c
> index f6e8a68..2c199b2 100644
> --- a/db/btblock.c
> +++ b/db/btblock.c
> @@ -250,23 +250,12 @@ const field_t bmapbtd_key_flds[] = {
> };
> #undef KOFF
>
> -#ifndef XFS_NATIVE_HOST
> -
> #define BMBT_EXNTFLAG_BITOFF 0
> #define BMBT_STARTOFF_BITOFF (BMBT_EXNTFLAG_BITOFF + BMBT_EXNTFLAG_BITLEN)
> #define BMBT_STARTBLOCK_BITOFF (BMBT_STARTOFF_BITOFF + BMBT_STARTOFF_BITLEN)
> #define BMBT_BLOCKCOUNT_BITOFF \
> (BMBT_STARTBLOCK_BITOFF + BMBT_STARTBLOCK_BITLEN)
>
> -#else
> -
> -#define BMBT_EXNTFLAG_BITOFF 63
> -#define BMBT_STARTOFF_BITOFF (BMBT_EXNTFLAG_BITOFF - BMBT_STARTOFF_BITLEN)
> -#define BMBT_STARTBLOCK_BITOFF 85 /* 128 - 43 (other 9 is in first word) */
> -#define BMBT_BLOCKCOUNT_BITOFF 64 /* Start of second 64 bit container */
> -
> -#endif /* XFS_NATIVE_HOST */
> -
> const field_t bmapbta_rec_flds[] = {
> { "startoff", FLDT_CFILEOFFA, OI(BMBT_STARTOFF_BITOFF), C1, 0,
> TYP_ATTR },
>
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