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From: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: propagating repo corruption across clone
Date: Sun, 24 Mar 2013 21:16:14 +0200	[thread overview]
Message-ID: <20130324191614.GA15275@LK-Perkele-VII> (raw)
In-Reply-To: <20130324183133.GA11200@sigill.intra.peff.net>

On Sun, Mar 24, 2013 at 02:31:33PM -0400, Jeff King wrote:
> 
> Fscking the incoming objects does work, but of course it comes at a cost
> in the normal case (for linux-2.6, I measured an increase in CPU time
> with "index-pack --strict" from ~2.5 minutes to ~4 minutes). And I think
> it is probably overkill for finding corruption; index-pack already
> recognizes bit corruption inside an object, and
> check_everything_connected can detect object graph problems much more
> cheaply.

AFAIK, standard checks index-pack has to do + checking that the object
graph has no broken links (and every ref points to something valid) will
catch everything except:

- SHA-1 collisions between corrupt objects and clean ones.
- Corrupted refs (that still point to something valid).
- "Born-corrupted" objects.

> One thing I didn't check is bit corruption inside a packed object that
> still correctly zlib inflates. check_everything_connected will end up
> reading all of the commits and trees (to walk them), but not the blobs.

Checking that everything is connected will (modulo SHA-1 collisions) save
you there, at least if packv3 is used as transport stream.

-Ilari

  parent reply	other threads:[~2013-03-24 19:24 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-24 18:31 propagating repo corruption across clone Jeff King
2013-03-24 19:01 ` Ævar Arnfjörð Bjarmason
2013-03-24 19:23   ` Jeff King
2013-03-25 13:43     ` Jeff Mitchell
2013-03-25 14:56       ` Jeff King
2013-03-25 15:31         ` Duy Nguyen
2013-03-25 15:56           ` Jeff King
2013-03-25 16:32             ` Jeff Mitchell
2013-03-25 20:07               ` Jeff King
2013-03-26 13:43                 ` Jeff Mitchell
2013-03-26 16:55                   ` Jeff King
2013-03-26 21:59                     ` Philip Oakley
2013-03-26 22:03                       ` Jeff King
2013-03-26 23:20                     ` Rich Fromm
2013-03-27  1:25                       ` Jonathan Nieder
2013-03-27 18:23                         ` Rich Fromm
2013-03-27 19:49                           ` Jeff King
2013-03-27 20:04                             ` Jeff King
2013-03-27  3:47                       ` Junio C Hamano
2013-03-27  6:19                         ` Sitaram Chamarty
2013-03-27 15:03                           ` Junio C Hamano
2013-03-27 15:47                             ` Sitaram Chamarty
2013-03-27 18:51                         ` Rich Fromm
2013-03-27 19:13                           ` Junio C Hamano
2013-03-28 13:52                           ` Jeff Mitchell
2013-03-28 13:48                         ` Jeff Mitchell
2013-03-26  1:06             ` Duy Nguyen
2013-03-24 19:16 ` Ilari Liusvaara [this message]
2013-03-25 20:01 ` Junio C Hamano
2013-03-25 20:05   ` Jeff King
2013-03-25 20:14 ` [PATCH 0/9] corrupt object potpourri Jeff King
2013-03-25 20:16   ` [PATCH 1/9] stream_blob_to_fd: detect errors reading from stream Jeff King
2013-03-26 21:27     ` Junio C Hamano
2013-03-25 20:17   ` [PATCH 2/9] check_sha1_signature: check return value from read_istream Jeff King
2013-03-25 20:18   ` [PATCH 3/9] read_istream_filtered: propagate read error from upstream Jeff King
2013-03-25 20:21   ` [PATCH 4/9] avoid infinite loop in read_istream_loose Jeff King
2013-03-25 20:21   ` [PATCH 5/9] add test for streaming corrupt blobs Jeff King
2013-03-25 21:10     ` Jonathan Nieder
2013-03-25 21:26       ` Jeff King
2013-03-27 20:27     ` Jeff King
2013-03-27 20:35       ` Junio C Hamano
2013-03-25 20:22   ` [PATCH 6/9] streaming_write_entry: propagate streaming errors Jeff King
2013-03-25 21:35     ` Eric Sunshine
2013-03-25 21:37       ` Jeff King
2013-03-25 21:39     ` Jonathan Nieder
2013-03-25 21:49       ` [PATCH v2 " Jeff King
2013-03-25 23:29         ` Jonathan Nieder
2013-03-26 21:38         ` Junio C Hamano
2013-03-25 20:22   ` [PATCH 7/9] add tests for cloning corrupted repositories Jeff King
2013-03-25 20:23   ` [PATCH 8/9] clone: die on errors from unpack_trees Jeff King
2013-03-26 21:40     ` Junio C Hamano
2013-03-26 22:22       ` [PATCH 10/9] clone: leave repo in place after checkout errors Jeff King
2013-03-26 22:32         ` Jonathan Nieder
2013-03-27  1:03           ` Jeff King
2013-03-25 20:26   ` [PATCH 9/9] clone: run check_everything_connected Jeff King
2013-03-26  0:53     ` Duy Nguyen
2013-03-26 22:24       ` Jeff King
2013-03-26 21:50     ` Junio C Hamano
2013-03-28  0:40     ` Duy Nguyen
2013-03-31  7:57       ` Duy Nguyen

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