dantso@bach.UUCP (04/09/87)
Sorry if this has been talked about before... We are in the middle of converting from 4.2BSD to Mt Xinu 4.3BSD+NFS. I noticed that when running 4.3BSD's fsck on 4.2BSD filesystems that it complains that the 4.2BSD directories are not multiples of 512 and ask to correct it. Should I say yes ? I hope I don't have to dump/restore all my 4.2BSD filesystems... Thanks.
dan@rna.UUCP (04/09/87)
Sorry if this has been talked about before... We are in the middle of converting from 4.2BSD to Mt Xinu 4.3BSD+NFS. I noticed that when running 4.3BSD's fsck on 4.2BSD filesystems that it complains that the 4.2BSD directories are not multiples of 512 and ask to correct it. Should I say yes ? I hope I don't have to dump/restore all my 4.2BSD filesystems... Thanks. Cheers, Dan Ts'o Dept. Neurobiology Rockefeller Univ. 1230 York Ave. NY, NY 10021 212-570-7671 ...cmcl2!rna!dan rna!dan@cmcl2.arpa
stevesu@copper.UUCP (04/11/87)
In article <622@rna.UUCP>, dan@rna.UUCP (Dan Ts'o) writes: > I noticed that when running 4.3BSD's fsck on 4.2BSD filesystems that it > complains that the 4.2BSD directories are not multiples of 512 and ask to > correct it. I was just reading through the 4.3 documentation, and I came across the following note ("Changes to the Kernel in 4.3BSD," section 4, under ufs_syscalls.c): _M_k_d_i_r now sets the size of all new directories to DIRBLKSIZE. Now, DIRBLKSIZE is DEV_BSIZE which is 512, and it's not inconceivable that efforts are also made to keep a directory a multiple of 512 bytes long once some real files are created within it. (For all I know, the 4.2 kernel does this too.) It would guess that the 512 character enforcement is just an efficiency tweak, although for a fully upgraded 4.3 filesystem, fsck's message would be a warning that 4.3 isn't keeping the directories as aligned as it thinks it is. In any case, I wouldn't worry about the warning, or about letting fsck fix the "problem." Steve Summit stevesu@copper.tek.com
chris@mimsy.UUCP (04/11/87)
[Capsule review: 4.3BSD fsck noisily adjusts all those old 24 byte directories to 512 bytes, and a few 512+24 byte directories to 1024 bytes, and so forth.] In article <8371@tekecs.TEK.COM> snoopy@doghouse.gwd.tek.com (Snoopy) writes: >My question is WHY does fsck (or anything else) care whether the >directory is a multiple of 512? It is really Just Another Consistency Check. It would also make life easier for the kernel if it could assume 512 byte directories: If you look deep in the heart of ufs_namei.c, you will see a comment about how the 4.2BSD `mkdir' was careless: N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. There should have been a note in the installation instructions about this, and indeed, `fsck -p' cleans this right up. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690) UUCP: seismo!mimsy!chris ARPA/CSNet: chris@mimsy.umd.edu
mangler@cit-vax.UUCP (04/12/87)
In article <8371@tekecs.TEK.COM>, snoopy@doghouse.gwd.tek.com (Snoopy) writes: > My question is WHY does fsck (or anything else) care whether the > directory is a multiple of 512? Some disk controllers (Xylogics) can only do I/O in units of whole sectors. Don Speck speck@vlsi.caltech.edu {seismo,rutgers,ames}!cit-vax!speck
guy@gorodish.UUCP (04/13/87)
>> My question is WHY does fsck (or anything else) care whether the >> directory is a multiple of 512? > >Some disk controllers (Xylogics) can only do I/O in units of whole sectors. That may be true, but it's also irrelevant. The UNIX file system code, as far as I can tell, always reads whole frags, and frags are rarely if ever smaller than a sector. (There exist 24-byte directories on a machine here with Xylogics disk controllers and it doesn't seem to mind.)
jeff@voder.UUCP (04/13/87)
> There should have been a note in the installation instructions about > this, and indeed, `fsck -p' cleans this right up. ... but, but, but ... the installation instructions *do* mention the change (on page 20). The original poster should perhaps have read "Installing and Operating 4.3BSD on the VAX" instead of assuming it was the same as the 4.2 doc. Of course, I'm assuming he has the doc set; if he doesn't, what's he doing with a tape? -- Jeff Gilliam {ucbvax,pyramid,nsc}!voder!jeff