Oh, you're right! Well, that will simplify things! All we have to do is convince a few bits of code to ignore ub_txg == 0. I'll try a couple of things and get back to you in a few hours...
Jeff On Fri, May 02, 2008 at 03:31:52AM -0700, Benjamin Brumaire wrote: > Hi, > > while diving deeply in zfs in order to recover data I found that every > uberblock in label0 does have the same ub_rootbp and a zeroed ub_txg. Does it > means only ub_txg was touch while detaching? > > Hoping it is the case, I modified ub_txg from one uberblock to match the tgx > from the label and now I try to calculate the new SHA256 checksum but I > failed. Can someone explain what I did wrong? And of course how to do it > correctly? > > bbr > > > The example is from a valid uberblock which belongs an other pool. > > Dumping the active uberblock in Label 0: > > # dd if=/dev/dsk/c0d1s4 bs=1 iseek=247808 count=1024 | od -x > 1024+0 records in > 1024+0 records out > 0000000 b10c 00ba 0000 0000 0009 0000 0000 0000 > 0000020 8bf2 0000 0000 0000 8eef f6db c46f 4dcc > 0000040 bba8 481a 0000 0000 0001 0000 0000 0000 > 0000060 05e6 0003 0000 0000 0001 0000 0000 0000 > 0000100 05e6 005b 0000 0000 0001 0000 0000 0000 > 0000120 44e9 00b2 0000 0000 0001 0000 0703 800b > 0000140 0000 0000 0000 0000 0000 0000 0000 0000 > 0000160 0000 0000 0000 0000 8bf2 0000 0000 0000 > 0000200 0018 0000 0000 0000 a981 2f65 0008 0000 > 0000220 e734 adf2 037a 0000 cedc d398 c063 0000 > 0000240 da03 8a6e 26fc 001c 0000 0000 0000 0000 > 0000260 0000 0000 0000 0000 0000 0000 0000 0000 > * > 0001720 0000 0000 0000 0000 7a11 b10c da7a 0210 > 0001740 3836 20fb e2a7 a737 a947 feed 43c5 c045 > 0001760 82a8 133d 0ba7 9ce7 e5d5 64e2 2474 3b03 > 0002000 > > Checksum is at pos 01740 01760 > > I try to calculate it assuming only uberblock is relevant. > #dd if=/dev/dsk/c0d1s4 bs=1 iseek=247808 count=168 | digest -a sha256 > 168+0 records in > 168+0 records out > 710306650facf818e824db5621be394f3b3fe934107bdfc861bbc82cb9e1bbf3 > > Helas not matching :-( > > > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
