From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f169.google.com ([209.85.223.169]:33793 "EHLO mail-io0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932104AbbKMTlT (ORCPT ); Fri, 13 Nov 2015 14:41:19 -0500 Received: by ioir85 with SMTP id r85so67059538ioi.1 for ; Fri, 13 Nov 2015 11:41:18 -0800 (PST) Subject: Re: illegal snapshot, cannot be deleted To: Hugo Mills , Vedran Vucic , linux-btrfs@vger.kernel.org References: <564486F3.5020804@gmail.com> <56461034.3070209@gmail.com> <56462784.2060601@gmail.com> <20151113184227.GF24333@carfax.org.uk> From: Austin S Hemmelgarn Message-ID: <56463CBC.70808@gmail.com> Date: Fri, 13 Nov 2015 14:40:44 -0500 MIME-Version: 1.0 In-Reply-To: <20151113184227.GF24333@carfax.org.uk> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms060300050505080504000605" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms060300050505080504000605 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-11-13 13:42, Hugo Mills wrote: > On Fri, Nov 13, 2015 at 01:10:12PM -0500, Austin S Hemmelgarn wrote: >> On 2015-11-13 12:30, Vedran Vucic wrote: >>> Hello, >>> >>> Here are outputs of commands as you requested: >>> btrfs fi df / >>> Data, single: total=3D8.00GiB, used=3D7.71GiB >>> System, DUP: total=3D32.00MiB, used=3D16.00KiB >>> Metadata, DUP: total=3D1.12GiB, used=3D377.25MiB >>> GlobalReserve, single: total=3D128.00MiB, used=3D0.00B >>> >>> btrfs fi show >>> Label: none uuid: d6934db3-3ac9-49d0-83db-287be7b995a5 >>> Total devices 1 FS bytes used 8.08GiB >>> devid 1 size 18.71GiB used 10.31GiB path /dev/sda6 >>> >>> btrfs-progs v4.0+20150429 >>> >> Hmm, that's odd, based on these numbers, you should be having no >> issue at all trying to run a balance. You might be hitting some >> other bug in the kernel, however, but I don't remember if there were >> any known bugs related to ENOSPC or balance in the version you're >> running. > > There's one specific bug that shows up with ENOSPC exactly like > this. It's in all versions of the kernel, there's no known solution, > and no guaranteed mitigation strategy, I'm afraid. Various things like > balancing, or adding, balancing, and removing a device again have been > tried. Sometimes they seem to help; sometimes they just make the > problem worse. > > We average maybe one report a week or so with this particular > set of symptoms. We should get this listed on the Wiki on the Gotcha's page ASAP,=20 especially considering that it's a pretty significant bug (not quite as=20 bad as data corruption, but pretty darn close). Vedran, could you try running the balance with just '-dusage=3D40' and=20 then again with just '-musage=3D40'? If just one of those fails, it coul= d=20 help narrow things down significantly. Hugo, is there anything else known about this issue (I don't recall=20 seeing it mentioned before, and a quick web search didn't turn up much)? = In particular: 1. Is there any known way to reliably reproduce it (I would assume not,=20 as that would likely lead to a mitigation strategy. If someone does=20 find a reliable reproducer, please let me know, I've got some=20 significant spare processor time and storage space I could dedicate to=20 getting traces and filesystem images for debugging, and already have=20 most of the required infrastructure set up for something like this)? 2. Is it contagious (that is, if I send a snapshot from a filesystem=20 that is affected by it, does the filesystem that receives the snapshot=20 become affected; if we could find a way to reproduce it, I could easily=20 answer this question within a couple of minutes of reproducing it)? 3. Do we have any kind of statistics beyond the rate of reports (for=20 example, does it happen more often on bigger filesystems, or possibly=20 more frequently with certain chunk profiles)? --------------ms060300050505080504000605 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgMFADCABgkqhkiG9w0BBwEAAKCC Brgwgga0MIIEnKADAgECAgMRLfgwDQYJKoZIhvcNAQENBQAweTEQMA4GA1UEChMHUm9vdCBD QTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNp Z25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcwHhcN MTUwOTIxMTEzNTEzWhcNMTYwMzE5MTEzNTEzWjBjMRgwFgYDVQQDEw9DQWNlcnQgV29UIFVz ZXIxIzAhBgkqhkiG9w0BCQEWFGFoZmVycm9pbjdAZ21haWwuY29tMSIwIAYJKoZIhvcNAQkB FhNhaGVtbWVsZ0BvaGlvZ3QuY29tMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEA nQ/81tq0QBQi5w316VsVNfjg6kVVIMx760TuwA1MUaNQgQ3NyUl+UyFtjhpkNwwChjgAqfGd LIMTHAdObcwGfzO5uI2o1a8MHVQna8FRsU3QGouysIOGQlX8jFYXMKPEdnlt0GoQcd+BtESr pivbGWUEkPs1CwM6WOrs+09bAJP3qzKIr0VxervFrzrC5Dg9Rf18r9WXHElBuWHg4GYHNJ2V Ab8iKc10h44FnqxZK8RDN8ts/xX93i9bIBmHnFfyNRfiOUtNVeynJbf6kVtdHP+CRBkXCNRZ qyQT7gbTGD24P92PS2UTmDfplSBcWcTn65o3xWfesbf02jF6PL3BCrVnDRI4RgYxG3zFBJuG qvMoEODLhHKSXPAyQhwZINigZNdw5G1NqjXqUw+lIqdQvoPijK9J3eijiakh9u2bjWOMaleI SMRR6XsdM2O5qun1dqOrCgRkM0XSNtBQ2JjY7CycIx+qifJWsRaYWZz0aQU4ZrtAI7gVhO9h pyNaAGjvm7PdjEBiXq57e4QcgpwzvNlv8pG1c/hnt0msfDWNJtl3b6elhQ2Pz4w/QnWifZ8E BrFEmjeeJa2dqjE3giPVWrsH+lOvQQONsYJOuVb8b0zao4vrWeGmW2q2e3pdv0Axzm/60cJQ haZUv8+JdX9ZzqxOm5w5eUQSclt84u+D+hsCAwEAAaOCAVkwggFVMAwGA1UdEwEB/wQCMAAw VgYJYIZIAYb4QgENBEkWR1RvIGdldCB5b3VyIG93biBjZXJ0aWZpY2F0ZSBmb3IgRlJFRSBo ZWFkIG92ZXIgdG8gaHR0cDovL3d3dy5DQWNlcnQub3JnMA4GA1UdDwEB/wQEAwIDqDBABgNV HSUEOTA3BggrBgEFBQcDBAYIKwYBBQUHAwIGCisGAQQBgjcKAwQGCisGAQQBgjcKAwMGCWCG SAGG+EIEATAyBggrBgEFBQcBAQQmMCQwIgYIKwYBBQUHMAGGFmh0dHA6Ly9vY3NwLmNhY2Vy dC5vcmcwMQYDVR0fBCowKDAmoCSgIoYgaHR0cDovL2NybC5jYWNlcnQub3JnL3Jldm9rZS5j cmwwNAYDVR0RBC0wK4EUYWhmZXJyb2luN0BnbWFpbC5jb22BE2FoZW1tZWxnQG9oaW9ndC5j b20wDQYJKoZIhvcNAQENBQADggIBADMnxtSLiIunh/TQcjnRdf63yf2D8jMtYUm4yDoCF++J jCXbPQBGrpCEHztlNSGIkF3PH7ohKZvlqF4XePWxpY9dkr/pNyCF1PRkwxUURqvuHXbu8Lwn 8D3U2HeOEU3KmrfEo65DcbanJCMTTW7+mU9lZICPP7ZA9/zB+L0Gm1UNFZ6AU50N/86vjQfY WgkCd6dZD4rQ5y8L+d/lRbJW7ZGEQw1bSFVTRpkxxDTOwXH4/GpQfnfqTAtQuJ1CsKT12e+H NSD/RUWGTr289dA3P4nunBlz7qfvKamxPymHeBEUcuICKkL9/OZrnuYnGROFwcdvfjGE5iLB kjp/ttrY4aaVW5EsLASNgiRmA6mbgEAMlw3RwVx0sVelbiIAJg9Twzk4Ct6U9uBKiJ8S0sS2 8RCSyTmCRhJs0vvva5W9QUFGmp5kyFQEoSfBRJlbZfGX2ehI2Hi3U2/PMUm2ONuQG1E+a0AP u7I0NJc/Xil7rqR0gdbfkbWp0a+8dAvaM6J00aIcNo+HkcQkUgtfrw+C2Oyl3q8IjivGXZqT 5UdGUb2KujLjqjG91Dun3/RJ/qgQlotH7WkVBs7YJVTCxfkdN36rToPcnMYOI30FWa0Q06gn F6gUv9/mo6riv3A5bem/BdbgaJoPnWQD9D8wSyci9G4LKC+HQAMdLmGoeZfpJzKHMYIE0TCC BM0CAQEwgYAweTEQMA4GA1UEChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNl cnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcN AQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DANBglghkgBZQMEAgMFAKCCAiEwGAYJKoZI hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUxMTEzMTk0MDQ0WjBPBgkq hkiG9w0BCQQxQgRAvusH9jMuGMqXABZZH13kbkAcu2toc1+4DUu8G+3IkUjkDBwmZGzu9eXV Am7lhEvJaw1uLvK6sOf7iff++5gGXTBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxEt+DCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DAN BgkqhkiG9w0BAQEFAASCAgCOQoX+kpnkjFola0PNJl4l6LcNX7VFkyIonr/WDmVFw/2eyNAE KmglSR7Wt0m1imHkbKqKlZH6xmI/IyToP66pNpX/WdDBzVJqaG7rRBW5lzXphk9ZDE7qFCvR Mo1NdsijvCRnRROWulZ8iTsDxywpnxGDk9kCCjU/hXKZED2UgzkyWP0eW4rQKcJJNd1xAAkV bPLqq7Ez62RbtWi3crrm0zIyWeGIR9dGXzgHVccXpAKROQHMu+TcrbiQJiWO0j3oDwN19cVB /kHmT22Ur/A2qdcrHguRWtomgzBzaujRQ8lsg1C/ktyVJ6cxTr/SE8GvHnlNj7YQVGaLPha4 vVrxbaqIBywSrdFjdxQ/m9S6ytra5seDFeIaA3h5gYYtkFtvGvsaAwak0F+DETYEzSFj/5T3 G9D23dv85oSqV/Zjldm5wzew+wsZZZp8psAVsCeUQkyAepd2kJh3huDnuqgg/HldO2IQy9rI wyeD2XS10RLDpvcIE+hO8tz80c7ps6F1OnDcrmLf6gdXXhWWCt/wlR8ONGFeKq/z3ARdSKuo apkTc11d6FP6rbb7JVS3oZ2XiHtQdlA7UQNk/Hg/grMAgj4F+mylDBRl2U8TpSu0nYwZyFKe UoNEPmHBoGPrluktQmMgVUs2IhO8w4rlMqqebjF7rAwFPjjsEmp9c9EArwAAAAAAAA== --------------ms060300050505080504000605--