# How to recovery a corrupted git repo 8 messages from 2011-02-21 to 2011-02-22. Participants: Ping Yin, Christian Couder, Axel Freyn, Matthieu Moy. Thread: https://gitlist.dev/t/26567 ## Ping Yin, 2011-02-21 07:50 Subject: How to recovery a corrupted git repo Message-ID: URL: https://gitlist.dev/e/AANLkTi%3DW3RckA%3De-YwDJzELaEOAa%2B7P74V-G0G%3DbQhex%40mail.gmail.com ``` I have a corrupted git repo, with "git fsck", it shows missing blob b71eb55f2dbc97dafd4a769fc61f346e69a5e0af missing blob 282035f3ae964e1e288f352c370be8edd11d3078 missing tree 3c20f556eecc476e3542cc522d46a62a4461fec6 missing blob f321b578edeb452358497e832815d6cae6b36886 missing commit 6d23f5084c975be637f7d748db82116bf84d3872 And i also have a good backup repo. How can i recover the corrupted repo with the backup repo? I can do a rsync or fresh "git clone", however, is there any git related commands to incrementally do this? btw, "git remote add and then git fetch" doesn't work, it reports error: refs/heads/bringup does not point to a valid object! error: refs/heads/fsl_imx_r9.3 does not point to a valid object! error: refs/heads/bringup does not point to a valid object! error: refs/heads/fsl_imx_r9.3 does not point to a valid object! error: refs/heads/bringup does not point to a valid object! error: refs/heads/fsl_imx_r9.3 does not point to a valid object! error: refs/heads/bringup does not point to a valid object! error: refs/heads/fsl_imx_r9.3 does not point to a valid object! error: missing object referenced by 'refs/tags/v2.6.32' error: missing object referenced by 'refs/tags/v2.6.32-rc1' error: missing object referenced by 'refs/tags/v2.6.32-rc2' ``` ## Christian Couder, 2011-02-21 09:27 Subject: Re: How to recovery a corrupted git repo Message-ID: URL: https://gitlist.dev/e/AANLkTimt1oR7nrhXmHugGooOAc3KTiDE6kQ3vGTznS9%2B%40mail.gmail.com In-Reply-To: ``` On Mon, Feb 21, 2011 at 8:50 AM, Ping Yin wrote: > I have a corrupted git repo, with "git fsck", it shows > > missing blob b71eb55f2dbc97dafd4a769fc61f346e69a5e0af > missing blob 282035f3ae964e1e288f352c370be8edd11d3078 > missing tree 3c20f556eecc476e3542cc522d46a62a4461fec6 > missing blob f321b578edeb452358497e832815d6cae6b36886 > missing commit 6d23f5084c975be637f7d748db82116bf84d3872 > > And i also have a good backup repo. How can i recover the corrupted > repo with the backup repo? Please, have a look this FAQ entry: https://git.wiki.kernel.org/index.php/GitFaq#How_to_fix_a_broken_repository.3F And tell us what you did according to it. Thanks, Christian. ``` ## Axel Freyn, 2011-02-21 10:04 Subject: Re: How to recovery a corrupted git repo Message-ID: <20110221100454.GM22168@axel> URL: https://gitlist.dev/e/20110221100454.GM22168%40axel In-Reply-To: ``` Hi, On Mon, Feb 21, 2011 at 03:50:09PM +0800, Ping Yin wrote: > I have a corrupted git repo, with "git fsck", it shows > > missing blob b71eb55f2dbc97dafd4a769fc61f346e69a5e0af > missing blob 282035f3ae964e1e288f352c370be8edd11d3078 > missing tree 3c20f556eecc476e3542cc522d46a62a4461fec6 > missing blob f321b578edeb452358497e832815d6cae6b36886 > missing commit 6d23f5084c975be637f7d748db82116bf84d3872 > > And i also have a good backup repo. How can i recover the corrupted > repo with the backup repo? > > I can do a rsync or fresh "git clone", however, is there any git > related commands to incrementally do this? I don't know whether there is a single git command to do it, but you can copy those 5 objects "by hand": in your backup, you should have a directory .git/objects, where you have the files b7/1eb55f2dbc97dafd4a769fc61f346e69a5e0af 28/2035f3ae964e1e288f352c370be8edd11d3078 3c/20f556eecc476e3542cc522d46a62a4461fec6 f3/21b578edeb452358497e832815d6cae6b36886 6d/23f5084c975be637f7d748db82116bf84d3872 It should be sufficient to just copy those files into the corrupted repo. However if you packed the git-files in the backup (e.g. by running "git gc"), those objects might be found in a pack in .git/objects/pack. The easiest ist probably to use git-unpack-objects to unpack the objects, and then copy the 5 missing objects. Axel PS: Well, I'm using git and I like it -- but I'm no specialist; so first do a backup, before you follow my proposal ;-) ``` ## Ping Yin, 2011-02-21 10:11 Subject: Re: How to recovery a corrupted git repo Message-ID: URL: https://gitlist.dev/e/AANLkTimAE4AOCYibrCRHaSJ-mHkrQm7yZbHNy3kWGj7-%40mail.gmail.com In-Reply-To: <20110221100454.GM22168@axel> ``` Thanks, axel and Christian. I am just look for a simpler method. since i have a full backup, finally , i do something like following git clone --bare --reference bad-repo.git foo.com:good-repo.git repo.git On Mon, Feb 21, 2011 at 6:04 PM, Axel Freyn wrote: > Hi, > On Mon, Feb 21, 2011 at 03:50:09PM +0800, Ping Yin wrote: >> I have a corrupted git repo, with "git fsck", it shows >> >> missing blob b71eb55f2dbc97dafd4a769fc61f346e69a5e0af >> missing blob 282035f3ae964e1e288f352c370be8edd11d3078 >> missing tree 3c20f556eecc476e3542cc522d46a62a4461fec6 >> missing blob f321b578edeb452358497e832815d6cae6b36886 >> missing commit 6d23f5084c975be637f7d748db82116bf84d3872 >> >> And i also have a good backup repo. How can i recover the corrupted >> repo with the backup repo? >> >> I can do a rsync or fresh "git clone", however, is there any git >> related commands to incrementally do this? > I don't know whether there is a single git command to do it, but you can > copy those 5 objects "by hand": in your backup, you should have a > directory .git/objects, where you have the files >   b7/1eb55f2dbc97dafd4a769fc61f346e69a5e0af >   28/2035f3ae964e1e288f352c370be8edd11d3078 >   3c/20f556eecc476e3542cc522d46a62a4461fec6 >   f3/21b578edeb452358497e832815d6cae6b36886 >   6d/23f5084c975be637f7d748db82116bf84d3872 > > It should be sufficient to just copy those files into the corrupted > repo. > > However if you packed the git-files in the backup (e.g. by running "git > gc"), those objects might be found in a pack in .git/objects/pack. > The easiest ist probably to use git-unpack-objects to unpack the > objects, and then copy the 5 missing objects. > > Axel > > PS: Well, I'm using git and I like it -- but I'm no specialist; so first > do a backup, before you follow my proposal ;-) > > -- > To unsubscribe from this list: send the line "unsubscribe git" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html > ``` ## Matthieu Moy, 2011-02-21 14:51 Subject: Re: How to recovery a corrupted git repo Message-ID: URL: https://gitlist.dev/e/vpqpqql1lw6.fsf%40bauges.imag.fr In-Reply-To: <20110221100454.GM22168@axel> ``` Axel Freyn writes: > I don't know whether there is a single git command to do it, but you can > copy those 5 objects "by hand": in your backup, you should have a > directory .git/objects, where you have the files > b7/1eb55f2dbc97dafd4a769fc61f346e69a5e0af > 28/2035f3ae964e1e288f352c370be8edd11d3078 > 3c/20f556eecc476e3542cc522d46a62a4461fec6 > f3/21b578edeb452358497e832815d6cae6b36886 > 6d/23f5084c975be637f7d748db82116bf84d3872 > > It should be sufficient to just copy those files into the corrupted > repo. > > However if you packed the git-files in the backup (e.g. by running "git > gc"), those objects might be found in a pack in .git/objects/pack. > The easiest ist probably to use git-unpack-objects to unpack the > objects, and then copy the 5 missing objects. There's also the brute-force approach rsync $good_repo/.git/objects/ $bad_repo/.git/objects/ cd $bad_repo git gc Notice the absence of --delete in the rsync command: I'm just adding new files in the $bad_repo, not deleting any (since files with identical names must have identical content). This will result in a lot of duplicates (objects found in several packs), but "git gc" should be able to remove them. (the notice about doing backups before also applies to my proposal ;-) ) -- Matthieu Moy http://www-verimag.imag.fr/~moy/ ``` ## Ping Yin, 2011-02-21 15:03 Subject: Re: How to recovery a corrupted git repo Message-ID: URL: https://gitlist.dev/e/AANLkTim-O%2BLR_r%3DN6y7Dcip8xQGcBVP2FiVhu22Zhysf%40mail.gmail.com In-Reply-To: ``` On Mon, Feb 21, 2011 at 10:51 PM, Matthieu Moy wrote: > Axel Freyn writes: > > There's also the brute-force approach > > rsync $good_repo/.git/objects/ $bad_repo/.git/objects/ > cd $bad_repo > git gc > > Notice the absence of --delete in the rsync command: I'm just adding > new files in the $bad_repo, not deleting any (since files with > identical names must have identical content). Thanks. This should be an applicable method. However, before rsyncing, the pack should be unpacked first. ``` ## Matthieu Moy, 2011-02-21 15:31 Subject: Re: How to recovery a corrupted git repo Message-ID: URL: https://gitlist.dev/e/vpqipwds8uh.fsf%40bauges.imag.fr In-Reply-To: ``` Ping Yin writes: > Thanks. This should be an applicable method. However, before rsyncing, > the pack should be unpacked first. No need. Just copying the pack files works too, and is way faster: /tmp/corrupted$ git fsck missing commit 4815c2955d5863005edc4ff61c0de42e9609a920 dangling tree c8b826f673e1f1edb0fb5dc58294148be06cd6cb /tmp/corrupted$ cp ../cloned/.git/objects/pack/pack-e34444a471a9cd3e6f2656b609ffa0d66cce1f9c.* .git/objects/pack/ /tmp/corrupted$ git fsck /tmp/corrupted$ git gc Counting objects: 12, done. Delta compression using up to 2 threads. Compressing objects: 100% (4/4), done. Writing objects: 100% (12/12), done. Total 12 (delta 0), reused 12 (delta 0) -- Matthieu Moy http://www-verimag.imag.fr/~moy/ ``` ## Ping Yin, 2011-02-22 03:16 Subject: Re: How to recovery a corrupted git repo Message-ID: URL: https://gitlist.dev/e/AANLkTi%3D_nn84FcvvkhiKUJgVG4EkyYWoUYLctarh7a9L%40mail.gmail.com In-Reply-To: ``` On Mon, Feb 21, 2011 at 11:31 PM, Matthieu Moy wrote: > Ping Yin writes: > >> Thanks. This should be an applicable method. However, before rsyncing, >> the pack should be unpacked first. > > No need. Just copying the pack files works too, and is way faster: > Great, thanks. ```