41 messages in org.freebsd.freebsd-fsRe: Anyone working on fsck?| From | Sent On | Attachments |
|---|---|---|
| Julian Elischer | Mar 17, 2003 12:22 pm | |
| Alfred Perlstein | Mar 17, 2003 12:32 pm | |
| Julian Elischer | Mar 17, 2003 12:39 pm | |
| Julian Elischer | Mar 17, 2003 12:44 pm | |
| Miguel Mendez | Mar 17, 2003 12:59 pm | |
| Bakul Shah | Mar 17, 2003 1:26 pm | |
| Poul-Henning Kamp | Mar 17, 2003 1:38 pm | |
| Julian Elischer | Mar 17, 2003 1:51 pm | |
| Julian Elischer | Mar 17, 2003 1:56 pm | |
| Bakul Shah | Mar 17, 2003 2:04 pm | |
| Bakul Shah | Mar 17, 2003 2:08 pm | |
| Brooks Davis | Mar 17, 2003 2:12 pm | |
| Julian Elischer | Mar 17, 2003 2:25 pm | |
| Jeff Roberson | Mar 17, 2003 2:30 pm | |
| Brad Knowles | Mar 17, 2003 2:39 pm | |
| Greg 'groggy' Lehey | Mar 17, 2003 3:48 pm | |
| Julian Elischer | Mar 17, 2003 4:04 pm | |
| Terry Lambert | Mar 17, 2003 7:41 pm | |
| Terry Lambert | Mar 17, 2003 7:43 pm | |
| Terry Lambert | Mar 17, 2003 7:49 pm | |
| Terry Lambert | Mar 17, 2003 7:58 pm | |
| Jeff Roberson | Mar 17, 2003 8:02 pm | |
| Terry Lambert | Mar 17, 2003 8:31 pm | |
| Kenneth D. Merry | Mar 17, 2003 8:34 pm | |
| Bakul Shah | Mar 17, 2003 8:59 pm | |
| Poul-Henning Kamp | Mar 17, 2003 10:17 pm | |
| Poul-Henning Kamp | Mar 17, 2003 10:23 pm | |
| Greg 'groggy' Lehey | Mar 17, 2003 10:47 pm | |
| Terry Lambert | Mar 17, 2003 10:48 pm | |
| Greg 'groggy' Lehey | Mar 17, 2003 10:53 pm | |
| Peter Wemm | Mar 17, 2003 11:45 pm | |
| Dag-Erling Smørgrav | Mar 18, 2003 1:58 am | |
| Miguel Mendez | Mar 18, 2003 2:08 am | |
| Brad Knowles | Mar 18, 2003 5:59 am | |
| Brad Knowles | Mar 18, 2003 6:04 am | |
| Brad Knowles | Mar 18, 2003 6:25 am | |
| Giorgos Keramidas | Mar 18, 2003 12:12 pm | |
| Brandon D. Valentine | Mar 18, 2003 12:24 pm | |
| Terry Lambert | Mar 18, 2003 2:41 pm | |
| Brad Knowles | Mar 18, 2003 4:15 pm | |
| Terry Lambert | Mar 18, 2003 4:33 pm |
| Subject: | Re: Anyone working on fsck? | |
|---|---|---|
| From: | Terry Lambert (tlam...@mindspring.com) | |
| Date: | Mar 18, 2003 4:33:01 pm | |
| List: | org.freebsd.freebsd-fs | |
Brad Knowles wrote:
At 2:42 PM -0800 2003/03/18, Terry Lambert wrote:
Make sense now?
No.
However, I am now convinced that I don't understand enough of how the filesystem works to even be able to ask the simplest of questions about how this process can be improved. So, I will now shut up.
You should read the "A Fast Filesystem for UNIX" paper by McKusick, et. al.. The Viva FS paper I mentioned the other day is also good background on placement policies.
Actually, I have thought out a (relatively) simple way of making all CG fsck's take a single pass, but it requires access to some free blocks on the FS itself, and it has a worrisome amount of writes that end up happening to the same region of the disk, so I don't know what it means for the failure rate.
The only space I can see to grab for it is something like the quota stuff, or to steal inode #1 from the whiteouts.
But the resulting fsck could be *guaranteed* to take only a single pass through the data. Further, it could be bounded, to ensure the fsck process does not need to swap data sets in hand (but compared to the single pass optimization, going from O(3)->O(1), that's just gravy). It would only require a single bit change to the superblock, too, if the space was found. Perhaps there is a "don't care" area available for this, like I suggested before UFS2 was started?
-- Terry
To Unsubscribe: send mail to majo...@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message