From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756527AbbJAOZS (ORCPT ); Thu, 1 Oct 2015 10:25:18 -0400 Received: from mail-qg0-f53.google.com ([209.85.192.53]:35843 "EHLO mail-qg0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752863AbbJAOZP (ORCPT ); Thu, 1 Oct 2015 10:25:15 -0400 Subject: Re: NFS / FuseFS Kernel Hangs Bug To: "sascha a." , linux-kernel@vger.kernel.org References: From: Austin S Hemmelgarn Message-ID: <560D4212.3010101@gmail.com> Date: Thu, 1 Oct 2015 10:24:18 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms030705020601070301040403" X-Antivirus: avast! (VPS 151001-0, 2015-10-01), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a cryptographically signed message in MIME format. --------------ms030705020601070301040403 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-10-01 09:06, sascha a. wrote: > Hello, > > > I want to report a Bug with NFS / FuseFS. > > Theres trouble with mounting a NFS FS with FuseFS, if the NFS Server > is slowly responding. > > The problem occurs, if you mount a NFS FS with FuseFS driver for > example with this command: > > mount -t nfs -o vers=3D3,nfsvers=3D3,hard,intr,tcp server /dest > > Working on this nfs overlay works like a charm, as long as the NFS > Server is not under heavy load. If it gets under HEAVY load from time > to time the kernel hangs (which should in my opinion never ever > occur). OK, before I start on an explanation of why what is happening is=20 happening, I should note that unless you're using some special FUSE=20 driver instead of the regular NFS tools, you're not using FUSE to mount=20 the NFS share, you're using a regular kernel driver. Now, on to the explanation: This behavior is expected and unavoidable for any network filesystem=20 under the described conditions. Sync (or any other command that causes=20 access to the filesystem that isn't served by the local cache) requires=20 sending a command to the server. Sync in particular is _synchronous_=20 (and it should be, otherwise you break the implied data safety from=20 using it), which means that it will wait until it gets a reply from the=20 server before it returns, which means that if the server is heavily=20 loaded (or just ridiculously slow), it will be a while before it=20 returns. On top of this, depending on how the server is caching data,=20 it may take a long time to return even on a really fast server with no=20 other load. The stacktrace you posted indicates simply that the kernel noticed that=20 'sync' was in an I/O sleep state (the 'D state' it refers to) for more=20 than 120 seconds, which is the default detection timeout for this. --------------ms030705020601070301040403 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 hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUxMDAxMTQyNDE4WjBPBgkq hkiG9w0BCQQxQgRA3NRGiqcqfyJ/eXaqSOJQ2EGzrJI0MSb5SdV51FHLavO4BDiUJLmrroCo gBwEZCNyqO9C3ymjG0G6qs4BX5PQszBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxEt+DCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DAN BgkqhkiG9w0BAQEFAASCAgANN5XSv4ffjwEK2zJ/9eqAXaHD6pKllfDVf29bJ3MoTnwykwGh 9zjyy9lyo1XUsuiLKFXzejtIlLl97Hqmut+c+X0OtvoErxlkH0TpNzUfsLBndWWhAw+eKNMH YWoyCxW5WGFXQPY8OQ9gjub2ByGJAqNX/iQfThHNXsMm0lN4ig6LIE3X7oyML7ihV8e4Jlc/ ms3hDSFWTha8yJCQpB8r2Qxie3JVfYsgEpdTMrc1zL/A1Pa9OVDkQVIZMBu4R4lC9O7M+CzT XqtCxUlrsYuxpK3Nl5+/szIEZuUkxo5cJz3kOjmGpetbmNXJ09lVZf6xKn/BicZQ6ZLr7vhX foXGqDTSqGytvfhVG2tOhCyfs8OJN565fbrBVBV6cDSs6UcZCCyJBEcKXKQUfIyfoh6FVv16 2cys1MpFHwC6cG76LjT1/Yn40Rt0ZyUaZWDxOP5vzJZ1AbqvZfE3Wr9f0xhoBuMOBfZa7RNX inVBEQ+wEkcLU330ZJue7gINX+HeDDN3I/eUBxeLPvCJ1nPiFJwWbLxS9XmHyB+hDQ8kb5xs XkTYAVlGUNiTZaY/+AEGOmsArYvAGkZgI3FPYEvXX11D58MRp0mKIRR2poJ5NtgLNTSybmQX +7US7tcYSznLOf4A9wlmKhLuzR6ZR9bcZ3Xwwt+XVjzewA8dDJijX0u7RAAAAAAAAA== --------------ms030705020601070301040403--