Re: [RFC PATCH] db: Stop core dumping on attr3 if block header is not recognized

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Apr 19, 2018 at 11:13:02AM +0200, Carlos Maiolino wrote:
> On Wed, Apr 18, 2018 at 08:44:35AM -0700, Darrick J. Wong wrote:
> > On Wed, Apr 18, 2018 at 11:49:35AM +0200, Carlos Maiolino wrote:
> > 
> > There are two possible magics for attr3 blocks -- this one, which is for
> > remote attr value blocks, and the xfs_da3_blkinfo magic for the attr
> > leaf and da node blocks.  Can you please fish out the second magic and
> > print that too?
> > 
> > Looks otherwise reasonable, and certainly better than the ASSERT.
> > 
> > --D
> > 
> 
> What do you think about this output. Using attr3 type trying to print a
> directory's leaf block.
> 
> xfs_db> type attr3
> Unknown attribute buffer type!
> xfs_db> p
> Unrecognized attr3 block, attempting to print magic numbers and/or blkinfo:
> Unrecognized attr3 block, attempting to print magic numbers and/or blkinfo:
> hdr.magic = 0
> hdr.info.hdr.forw = 0
> hdr.info.hdr.back = 0
> hdr.info.hdr.magic = 0x3df1

I like it better, though on further thought I think I like better the
idea of printing the contents of all potential magic numbers:

For a block starting with:

0xDE 0xAD 0xBE 0xEF 0xCA 0xFE 0xF0 0x0D 0xBA 0xAD...

xfs_db> p
Unrecognized attr3 block, attempting to print magic numbers and/or blkinfo:
unknown.blockhdr.magic = 0xDEADBEEF
unknown.da_blkinfo.magic = 0xBAAD
unknown.inode.magic = 0xDEAD

--D

> hdr.info.crc = 0x72e2e910 (correct)
> hdr.info.bno = 64
> hdr.info.lsn = 0x300002833
> hdr.info.uuid = 2b21796f-7f81-4cec-b583-968c55b7f4bb
> hdr.info.owner = 99
> xfs_db> 
> 
> -- 
> Carlos
> --
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