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From:   Long Li <longli@microsoft.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     Bart Van Assche <bvanassche@acm.org>,
        "longli@linuxonhyperv.com" <longli@linuxonhyperv.com>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Hans de Goede <hdegoede@redhat.com>,
        "Williams, Dan J" <dan.j.williams@intel.com>,
        Maximilian Luz <luzmaximilian@gmail.com>,
        Mike Rapoport <rppt@kernel.org>,
        Ben Widawsky <ben.widawsky@intel.com>,
        Jiri Slaby <jirislaby@kernel.org>,
        Andra Paraschiv <andraprs@amazon.com>,
        Siddharth Gupta <sidgup@codeaurora.org>,
        Hannes Reinecke <hare@suse.de>
Subject: RE: [Patch v5 0/3] Introduce a driver to support host accelerated
 access to Microsoft Azure Blob for Azure VM
Thread-Topic: [Patch v5 0/3] Introduce a driver to support host accelerated
 access to Microsoft Azure Blob for Azure VM
Thread-Index: AQHXiceSNIn8c8rqq0aMs/Uc2xnVEKtlJaUAgAARXqCAAAZzgIADIFJggAC3SwCAAv3hYIBE4/SggAyEiKA=
Date:   Thu, 30 Sep 2021 22:25:12 +0000
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References: <1628146812-29798-1-git-send-email-longli@linuxonhyperv.com>
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> Subject: RE: [Patch v5 0/3] Introduce a driver to support host accelerate=
d
> access to Microsoft Azure Blob for Azure VM
>=20
> > Subject: RE: [Patch v5 0/3] Introduce a driver to support host
> > accelerated access to Microsoft Azure Blob for Azure VM
> >
> > > Subject: Re: [Patch v5 0/3] Introduce a driver to support host
> > > accelerated access to Microsoft Azure Blob for Azure VM
> > >
> > > On Sat, Aug 07, 2021 at 06:29:06PM +0000, Long Li wrote:
> > > > > I still think this "model" is totally broken and wrong overall.
> > > > > Again, you are creating a custom "block" layer with a character
> > > > > device, forcing all userspace programs to use a custom library
> > > > > (where is it
> > > at?) just to get their data.
> > > >
> > > > The Azure Blob library (with source code) is available in the
> > > > following
> > > languages:
> > > > Java:
> > > >
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F
> > > > gi
> > > > th
> > > > ub.com%2FAzure%2Fazure-sdk-for-
> > > java%2Ftree%2Fmain%2Fsdk%2Fstorage%2Faz
> > > > ure-storage-
> > > blob&amp;data=3D04%7C01%7Clongli%40microsoft.com%7C778083147
> > > >
> > > 8ed49b16e6308d95a2b7ae8%7C72f988bf86f141af91ab2d7cd011db47%7C1
> > > %7C0%7C6
> > > >
> > >
> 37639965101378114%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM
> > > DAiLCJQIjoi
> > > >
> > >
> V2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=3DwcNhsEo
> H
> > > LV0VBc
> > > > uDf0CVXl7W0Ug9Cj7Q92%2Bw6qizroU%3D&amp;reserved=3D0
> > > > JavaScript:
> > > >
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F
> > > > gi
> > > > th
> > > > ub.com%2FAzure%2Fazure-sdk-for-
> > > js%2Ftree%2Fmain%2Fsdk%2Fstorage%2Fstor
> > > > age-
> > >
> blob&amp;data=3D04%7C01%7Clongli%40microsoft.com%7C7780831478ed49b
> > > 16
> > > >
> > > e6308d95a2b7ae8%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C
> > > 637639965
> > > >
> > >
> 101378114%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIj
> o
> > > iV2luMzIi
> > > >
> > >
> LCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=3DI%2FfhdPX3Unz6S
> 3
> > > eBPcpl
> > > > %2Bh55nKoV0u%2FO0%2BYgjLy4grQ%3D&amp;reserved=3D0
> > > > Python:
> > > >
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F
> > > > gi
> > > > th
> > > > ub.com%2FAzure%2Fazure-sdk-for-
> > > python%2Ftree%2Fmain%2Fsdk%2Fstorage%2F
> > > > azure-storage-
> > > blob&amp;data=3D04%7C01%7Clongli%40microsoft.com%7C7780831
> > > >
> > > 478ed49b16e6308d95a2b7ae8%7C72f988bf86f141af91ab2d7cd011db47%7
> > > C1%7C0%7
> > > >
> > >
> C637639965101378114%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAw
> > > MDAiLCJQIj
> > > >
> > >
> oiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=3DaAwsi%
> 2
> > > BPVsN
> > > > tsDMJ7rKnRDigNc41fIao031lde247Nc0%3D&amp;reserved=3D0
> > > > Go:
> > > >
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F
> > > > gi
> > > > th
> > > > ub.com%2FAzure%2Fazure-storage-blob-
> > > go&amp;data=3D04%7C01%7Clongli%40mic
> > > >
> > >
> rosoft.com%7C7780831478ed49b16e6308d95a2b7ae8%7C72f988bf86f141a
> > > f91ab2d
> > > >
> > >
> 7cd011db47%7C1%7C0%7C637639965101378114%7CUnknown%7CTWFpbG
> > > Zsb3d8eyJWIj
> > > >
> > >
> oiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1
> 0
> > > 00&am
> > > >
> > >
> p;sdata=3D43JhbGsYQxA%2FoivNd7C3z7DSYO%2FPONCoaW2v7TN6xEU%3D&a
> > > mp;reserve
> > > > d=3D0
> > > > .NET:
> > > >
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F
> > > > gi
> > > > th
> > > > ub.com%2FAzure%2Fazure-sdk-for-
> > > net%2Ftree%2Fmain%2Fsdk%2Fstorage%2FAzu
> > > >
> > >
> re.Storage.Blobs&amp;data=3D04%7C01%7Clongli%40microsoft.com%7C77808
> > > 3147
> > > >
> > > 8ed49b16e6308d95a2b7ae8%7C72f988bf86f141af91ab2d7cd011db47%7C1
> > > %7C0%7C6
> > > >
> > >
> 37639965101378114%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM
> > > DAiLCJQIjoi
> > > >
> > >
> V2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=3D6ClMeURl
> t
> > > cBv1q
> > > > 7l7PGGrxXVJbVDt9uMBlwoIVh7Wpw%3D&amp;reserved=3D0
> > > > PHP:
> > > >
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F
> > > > gi
> > > > th
> > > > ub.com%2FAzure%2Fazure-storage-php%2Ftree%2Fmaster%2Fazure-
> > > storage-blo
> > > >
> > >
> b&amp;data=3D04%7C01%7Clongli%40microsoft.com%7C7780831478ed49b16
> > > e6308d9
> > > >
> > > 5a2b7ae8%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C6376399
> > > 651013781
> > > >
> > >
> 14%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM
> zIi
> > > LCJBTiI
> > > >
> > >
> 6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=3DDuZO539vd76c%2Byaqjn
> > > hetp%2B3T
> > > > i0b74601ZkNe39SNK4%3D&amp;reserved=3D0
> > > > Ruby:
> > > >
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2F
> > > > gi
> > > > th
> > > > ub.com%2Fazure%2Fazure-storage-
> > > ruby%2Ftree%2Fmaster%2Fblob&amp;data=3D04
> > > > %7C01%7Clongli%40microsoft.com%7C7780831478ed49b16e6308d95a2
> b
> > > 7ae8%7C72
> > > >
> > > f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637639965101378114%7
> > > CUnknown%
> > > >
> > >
> 7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haW
> wi
> > > LCJX
> > > >
> > >
> VCI6Mn0%3D%7C1000&amp;sdata=3D6Zviu1IuRQE2do9bDCae2iJv0W2KOJu90t
> > > XSR6kDAR
> > > > 4%3D&amp;reserved=3D0
> > > > C++:
> > > >
> > >
> C++https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2
> > > C++Fg
> > > > C++ithub.com%2FAzure%2Fazure-sdk-for-
> > > cpp%2Ftree%2Fmain%2Fsdk%2Fstorage
> > > > C++%23azure-storage-client-library-for-
> > > c&amp;data=3D04%7C01%7Clongli%40m
> > > >
> > >
> C++icrosoft.com%7C7780831478ed49b16e6308d95a2b7ae8%7C72f988bf86
> > > f141af9
> > > >
> > > C++1ab2d7cd011db47%7C1%7C0%7C637639965101388074%7CUnknown%
> > > 7CTWFpbGZsb3
> > > >
> > >
> >
> C++d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6
> Mn
> > > 0%3
> > > >
> > >
> C++D%7C1000&amp;sdata=3DHH6jrqREWQ%2BkoRR%2Fsb02wRXnuLU5il4Erzm
> > > rBvUZu5w%
> > > > C++3D&amp;reserved=3D0
> > >
> > > And why wasn't this linked to in the changelog here?
> > >
> > > In looking at the C code above, where is the interaction with this Li=
nux
> driver?
> > > I can't seem to find it...
>=20
> Greg,
>=20
> I apologize for the delay. I have attached the Java transport library (a =
tgz file)
> in the email. The file is released for review under "The MIT License (MIT=
)".
>=20
> The transport library implemented functions needed for reading from a Blo=
ck
> Blob using this driver. The function for transporting I/O is
> Java_com_azure_storage_fastpath_driver_FastpathDriver_read(), defined
> in "./src/fastpath/jni/fpjar_endpoint.cpp".
>=20
> In particular, requestParams is in JSON format (REST) that is passed from=
 a
> Blob application using Blob API for reading from a Block Blob.
>=20
> For an example of how a Blob application using the transport library, ple=
ase
> see Blob support for Hadoop ABFS:
> https://nam06.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Fgith
> ub.com%2Fapache%2Fhadoop%2Fpull%2F3309%2Fcommits%2Fbe7d12662e2
> 3a13e6cf10cf1fa5e7eb109738e7d&amp;data=3D04%7C01%7Clongli%40microsof
> t.com%7C3acb68c5fd6144a1857908d97e247376%7C72f988bf86f141af91ab2d7
> cd011db47%7C1%7C0%7C637679518802561720%7CUnknown%7CTWFpbGZsb
> 3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0
> %3D%7C1000&amp;sdata=3D6z3ZXPtMC5OvF%2FgrtbcRdFlqzzR1xJNRxE2v2Qrx
> FL8%3D&amp;reserved=3D0
>=20
> In ABFS, the entry point for using Blob I/O is at AbfsRestOperation
> executeRead() in hadoop-tools/hadoop-
> azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStr
> eam.java, from line 553 to 564, this function eventually calls into
> executeFastpathRead() in hadoop-tools/hadoop-
> azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsClient.ja
> va.
>=20
> ReadRequestParameters is the data that is passed to requestParams
> (described above) in the transport library. In this Blob application use-=
case,
> ReadRequestParameters has eTag and sessionInfo (sessionToken). They are
> both defined in this commit, and are treated as strings passed in JSON fo=
rmat
> to I/O issuing function
> Java_com_azure_storage_fastpath_driver_FastpathDriver_read() in the
> transport library using this driver.
>=20
> Thanks,
> Long

Hello Greg,

I have shared the source code of the Blob client using this driver, and the=
 reason why the Azure Blob driver is not implemented through POSIX with fil=
e system and Block layer.

Blob APIs are specified in this doc:
https://docs.microsoft.com/en-us/rest/api/storageservices/blob-service-rest=
-api

The semantic of reading data from Blob is specified in this doc:
https://docs.microsoft.com/en-us/rest/api/storageservices/get-blob

The source code I shared demonstrated how a Blob is read to Hadoop through =
ABFS. In general, A Blob client can use any optional request headers specif=
ied in the API suitable for its specific application. The Azure Blob servic=
e is not designed to be POSIX compliant. I hope this answers your question =
on why this driver is not implemented at file system or block layer.

Do you have more comments on this driver?

Thanks,
Long