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xfs_db: Fix extent record printing on big endian

PATCH In review Eric Sandeen 3 participants 3 messages Jun 20, 2012 – Jul 13, 2012

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#0 lore raw

PATCH 1/1 xfs_db: Fix extent record printing on big endian

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.

---

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!

db/btblock.c +0 -11
index f6e8a68..2c199b2 100644
@@ -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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#1 lore raw
Quoted 6 lines · Eric Sandeen

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:

Quoted 7 lines

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

Quoted 36 lines

---

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!

db/btblock.c +0 -11
index f6e8a68..2c199b2 100644
@@ -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 },
Quoted 5 lines

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_______________________________________________
xfs mailing list
[email protected]
http://oss.sgi.com/mailman/listinfo/xfs