On Thu, Feb 27, 2014 at 07:43:41PM -0600, Eric Sandeen wrote: > On 2/27/14, 6:53 PM, Dave Chinner wrote: > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > The discontiguous buffer support series added a verifier check on > > the metadata buffers before they go written to the metadump image. > > If this failed, it returned an error, and the restul woul dbe that > > we stopped processing the metadata and exited, resulting in a > > truncated dump. > > > > xfs_metadump is supposed to dump the metadata in the filesystem > > for forensic analysis purposes, which means we actually want it to > > retain any corruptions it finds in the filesystem. Hence running the > > verifier - even to recalculate CRCs - is the wrong thing to be > > doing. And stopping the dum pwhen we come across an error is even > > worse. > > > > Therefore remove the code tha truns the verifier and causes all > > these problems and replace it with a comment explaining why we don't > > want to run verifiers in the metadump process. > > This leaves the net functional change from > 8ab75c db: enable metadump on CRC filesystems > as: > > @@ -1727,6 +1743,9 @@ copy_inode_chunk( > > if (!process_inode(agno, agino + i, dip)) > goto pop_out; > + > + /* calculate the new CRC for the inode */ > + xfs_dinode_calc_crc(mp, dip); > } > skip_processing: > if (!write_buf(iocur_top)) > > which seems a) minimal, but also b) like we shouldn't be recalculating > CRCs if the point is to copy out existing fs state...? > > OTOH if we're obfuscating, we would HAVE to recalculate CRCs, > but then would lose the info that the CRC was bad before. > > So probably should skip CRC recalculating if the original CRC > was bad, in the obfuscating case? Yeah, you are right - I wasn't thinking of the obfuscation case changing the metadata.... > Maybe this patch stands ok on its own but it seems like there's > more work to do. :) I'll rework it. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
