Rick C. Petty wrote this message on Sun, Sep 14, 2003 at 12:52 -0500: > Hello. I posted a message to ports yesterday regarding the status of > sysutils/ffsrecov, which won't compile with UFS2 headers. I'm in dire need > of reconnecting or dumping inodes (well the associated files) because of a > pair of crashes causing fsck to fail due to "unreferenced files".
Sorry, must of missed that. I'm the author of ffsrecov, and I haven't updated mainly because I haven't had a system w/ UFS2 to really test on. I might be able to get to it in the next week or two, but I assume that you need it sooner. > A few years back I did a bunch of work with UFS1/FFS including a few > personal utilities to dump unconnected files, etc. I know the UFS1 > implementation pretty well, but that was prior to the use of soft updates > or the new UFS2. I'd like to pull the valuable data off this drive before > I fsck it clean and thus modify the file system. My question(s) concern > the differences between UFS1 & UFS2 and the use of soft updates. I would recommend if you can is to dump it to another filesystem or to tape.. then you can reinstall and recover the data at a more leisurely pace.. I had to do this when I originally wrote ffsrecov. Part of the reason you couldn't recover direct from device in the early versions. > AFAICT, soft-updates affects the in-memory copy and does not affect the > structures on the FS itself, just the order in which those structures are > updated to improve performance. I therefore assume that the FS structure > is similar to the original UFS1/FFS and could use my old utilities to dump > the files without modification. The concern is that possibly soft updates > was interrupted during a metadata write and maybe the inode or something > else became corrupt; I can't imagine how, I just wanted to verify that this > wouldn't happen. Most IDE disks have write caching enabled, and if the system powers off before the data is writen to disk, softupdates will think that the write hit the disk when infact it hadn't yet. > It seems to me that the basic differences between UFS1 & UFS2 are the new > ACLs and extended attributes, both of which don't change the underlying > format of the file system. It is my guess that I should be able to repair > this and even recompile ffsrecov using the old UFS headers. I'm also > guessing that I should be able to throw the drives into an older freebsd > system (w/o UFS2) and recover it that way. Please let me know if I'm way > off base here. Another really big difference is that the size of the blocks are different.. There is also a different way of listing blocks relating to the file. This was changed to a more dynamic approch and so it looks more like extents while keeping the advantages of the old way. (Thanks for your presentation at BSDcon, Kirk!) > On a related note, the soft-updates document, > http://www.usenix.org/publications/library/proceedings/usenix99/mckusick.html > implies that the unconnected inodes I'm seeing with fsck are files that > were deleted when the system was previously up, whose metadata was written > but whose inodes' link counts weren't decremented yet. In such a case, > these "unreferenced files" should be unimportant. I still wish to dump the > inodes because one of my drives had a low-level failure (hence why the > system crashed twice in a row) and after fsck-ing some important files did > disappear without a trace (I have a list of inodes and the FS was only > mounted read-only to verify the file integrity). -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not." _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
