From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f177.google.com ([209.85.223.177]:39477 "EHLO mail-ie0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754702AbaLVUdn (ORCPT ); Mon, 22 Dec 2014 15:33:43 -0500 Received: by mail-ie0-f177.google.com with SMTP id rd18so4953720iec.36 for ; Mon, 22 Dec 2014 12:33:42 -0800 (PST) Message-ID: <54988021.8010408@gmail.com> Date: Mon, 22 Dec 2014 15:33:37 -0500 From: Austin S Hemmelgarn MIME-Version: 1.0 To: Richard Sharpe CC: linux-btrfs@vger.kernel.org Subject: Re: Can BTRFS handle XATTRs larger than 4K? References: <54982A79.1090102@gmail.com> <54985E4C.40003@gmail.com> In-Reply-To: Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms030402010701000802010905" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms030402010701000802010905 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 2014-12-22 15:04, Richard Sharpe wrote: > On Mon, Dec 22, 2014 at 10:09 AM, Austin S Hemmelgarn > wrote: >> On 2014-12-22 12:27, Richard Sharpe wrote: >>> >>> On Mon, Dec 22, 2014 at 6:28 AM, Austin S Hemmelgarn >>> wrote: >>>> >>>> On 2014-12-19 21:07, Richard Sharpe wrote: >>>>> >>>>> >>>>> Hi folks, >>>>> >>>>> I need a Linux file system that supports XATTRs up to 64K. >>>>> >>>>> Can BTRFS support that or is XFS the only Linux file system with su= ch >>>>> support? >>>>> >>>> At the moment, BTRFS is limited to xattrs that fit inline in the met= adata >>>> nodes (so ~3900 bytes for a 4k leafsize). >>>> >>>> XFS, however, isn't the only Linux filesystem that supports xattrs t= hat >>>> size. Assuming that you are using a recent kernel, you can also use= such >>>> xattrs on at least: >>>> * XFS >>>> * JFS >>>> * ext4 >>>> * reiserfs (I think, not 100% certain about this one though) >>>> * OCFS2 (even though it is technically a cluster fs, it can be ru= n >>>> single >>>> node without the clustering) >>>> * ZFS (IIRC, ZFS supports unlimited xattr size) >>>> * NTFS (no limit on xattr size, though you should use NTFS-3G ins= tead >>>> of >>>> the in-kernel driver) >>>> * SquashFS (read-only) >>>> * HFS+ (Also no limit on xattr size) >>>> Of these, I'd personally suggest using XFS unless you need to be abl= e to >>>> shrink the filesystem, in which case I'd suggest ext4. >>> >>> >>> Thanks for the info. I hadn't realized that ext4 had lifted the >>> restriction. >>> >> Yeah, it would be nice if there was more clarity in the documentation.= >> >> Personally, I'd love to see unlimited length xattr's like NTFS and HFS= + do, >> as that would greatly improve interoperability (both Windows and OS X = use >> xattrs, although they call them 'alternative data streams' and 'forks'= >> respectively), and provide a higher likelihood that xattrs would start= >> getting used more. > > Well, there is a big difference in the semantics of Alternate Data > Streams (ADSs) and XATTRs. > > For example, you can seek on an ADS and read at any offset. You cannot > do that on an XATTR (at least, not with the semantics provided by the > UNIX interface.) > I'm not trying to say the semantics are identical, just that the=20 functionality is pretty similar. A better way to put it would be that=20 xattrs are an extremely limited form of ADS/Forks. --------------ms030402010701000802010905 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIFuDCC BbQwggOcoAMCAQICAw9gVDANBgkqhkiG9w0BAQ0FADB5MRAwDgYDVQQKEwdSb290IENBMR4w HAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmlu ZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0xNDA4 MDgxMTMwNDRaFw0xNTAyMDQxMTMwNDRaMGMxGDAWBgNVBAMTD0NBY2VydCBXb1QgVXNlcjEj MCEGCSqGSIb3DQEJARYUYWhmZXJyb2luN0BnbWFpbC5jb20xIjAgBgkqhkiG9w0BCQEWE2Fo ZW1tZWxnQG9oaW9ndC5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDdmm8R BM5D6fGiB6rpogPZbLYu6CkU6834rcJepfmxKnLarYUYM593/VGygfaaHAyuc8qLaRA3u1M0 Qp29flqmhv1VDTBZ+zFu6JgHjTDniBii1KOZRo0qV3jC5NvaS8KUM67+eQBjm29LhBWVi3+e a8jLxmogFXV0NGej+GHIr5zA9qKz2WJOEoGh0EfqZ2MQTmozcGI43/oqIYhRj8fRMkWXLUAF WsLzPQMpK19hD8fqwlxQWhBV8gsGRG54K5pyaQsjne7m89SF5M8JkNJPH39tHEvfv2Vhf7EM Y4WGyhLAULSlym1AI1uUHR1FfJaj3AChaEJZli/AdajYsqc7AgMBAAGjggFZMIIBVTAMBgNV HRMBAf8EAjAAMFYGCWCGSAGG+EIBDQRJFkdUbyBnZXQgeW91ciBvd24gY2VydGlmaWNhdGUg Zm9yIEZSRUUgaGVhZCBvdmVyIHRvIGh0dHA6Ly93d3cuQ0FjZXJ0Lm9yZzAOBgNVHQ8BAf8E BAMCA6gwQAYDVR0lBDkwNwYIKwYBBQUHAwQGCCsGAQUFBwMCBgorBgEEAYI3CgMEBgorBgEE AYI3CgMDBglghkgBhvhCBAEwMgYIKwYBBQUHAQEEJjAkMCIGCCsGAQUFBzABhhZodHRwOi8v b2NzcC5jYWNlcnQub3JnMDEGA1UdHwQqMCgwJqAkoCKGIGh0dHA6Ly9jcmwuY2FjZXJ0Lm9y Zy9yZXZva2UuY3JsMDQGA1UdEQQtMCuBFGFoZmVycm9pbjdAZ21haWwuY29tgRNhaGVtbWVs Z0BvaGlvZ3QuY29tMA0GCSqGSIb3DQEBDQUAA4ICAQCr4klxcZU/PDRBpUtlb+d6JXl2dfto OUP/6g19dpx6Ekt2pV1eujpIj5whh5KlCSPUgtHZI7BcksLSczQbxNDvRu6LNKqGJGvcp99k cWL1Z6BsgtvxWKkOmy1vB+2aPfDiQQiMCCLAqXwHiNDZhSkwmGsJ7KHMWgF/dRVDnsl6aOQZ jAcBMpUZxzA/bv4nY2PylVdqJWp9N7x86TF9sda1zRZiyUwy83eFTDNzefYPtc4MLppcaD4g Wt8U6T2ffQfCWVzDirhg4WmDH3MybDItjkSB2/+pgGOS4lgtEBMHzAGQqQ+5PojTHRyqu9Jc O59oIGrTaOtKV9nDeDtzNaQZgygJItJi9GoAl68AmIHxpS1rZUNV6X8ydFrEweFdRTVWhUEL 70Cnx84YBojXv01LYBSZaq18K8cERPLaIrUD2go+2ffjdE9ejvYDhNBllY+ufvRizIjQA1uC OdktVAN6auQob94kOOsWpoMSrzHHvOvVW/kbokmKzaLtcs9+nJoL+vPi2AyzbaoQASVZYOGW pE3daA0F5FJfcPZKCwd5wdnmT3dU1IRUxa5vMmgjP20lkfP8tCPtvZv2mmI2Nw5SaXNY4gVu WQrvkV2in+TnGqgEIwUrLVbx9G6PSYZZs07czhO+Q1iVuKdAwjL/AYK0Us9v50acIzbl5CWw ZGj3wjGCA6EwggOdAgEBMIGAMHkxEDAOBgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6 Ly93d3cuY2FjZXJ0Lm9yZzEiMCAGA1UEAxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEh MB8GCSqGSIb3DQEJARYSc3VwcG9ydEBjYWNlcnQub3JnAgMPYFQwCQYFKw4DAhoFAKCCAfUw GAYJKoZIhvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTQxMjIyMjAzMzM3 WjAjBgkqhkiG9w0BCQQxFgQUMz1MKtjFugSxtoaDRwaO0Qmg8AgwbAYJKoZIhvcNAQkPMV8w XTALBglghkgBZQMEASowCwYJYIZIAWUDBAECMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIA gDANBggqhkiG9w0DAgIBQDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKDCBkQYJKwYBBAGCNxAE MYGDMIGAMHkxEDAOBgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6Ly93d3cuY2FjZXJ0 Lm9yZzEiMCAGA1UEAxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEhMB8GCSqGSIb3DQEJ ARYSc3VwcG9ydEBjYWNlcnQub3JnAgMPYFQwgZMGCyqGSIb3DQEJEAILMYGDoIGAMHkxEDAO BgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6Ly93d3cuY2FjZXJ0Lm9yZzEiMCAGA1UE AxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEhMB8GCSqGSIb3DQEJARYSc3VwcG9ydEBj YWNlcnQub3JnAgMPYFQwDQYJKoZIhvcNAQEBBQAEggEA0hVrMGtbvwI7mMpVgQB/ryGrrvuI 3XuTZ1uqFTCSVoHt1QLa7vSu+Qbx7jUWBIQPpQG8kyVyH5ElE8/R01isF/zYqm7vbyl3AhHX tGjyC4jra5bhmvHL2c4vnKXJQI7RHVXIOaXjnb3ocCmJMyBO5R3Mp6P0XBOc/xfPv/wzbhcP 7lBkz/YjXwZODucF85hRTxTnv0gCqlhlfo/SpBdYxNi6IopRyMwnVXx1BaXuuagpd12vZzzs r55mYt9kDEtifesI4yYCy7EICOGj5aeMybBIyK7eFcNMRH8DascOQ8dNY2TBce21BKo+WaD2 VC//Sfjt+/bVP7UGkv6inXMVRAAAAAAAAA== --------------ms030402010701000802010905--