<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs/nfs/objlayout, branch linux-3.7.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>umount oops when remove blocklayoutdriver first</title>
<updated>2013-02-27T17:21:10+00:00</updated>
<author>
<name>fanchaoting</name>
<email>fanchaoting@cn.fujitsu.com</email>
</author>
<published>2013-02-04T13:15:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0a41d4134695a7059c1cc5d0ac57f44c9e0a54a1'/>
<id>0a41d4134695a7059c1cc5d0ac57f44c9e0a54a1</id>
<content type='text'>
commit 5a12cca697aca5dfba42a7d4c3356acc0445a2b0 upstream.

now pnfs client uses block layout, maybe we can remove
blocklayoutdriver first. if we umount later,
it can cause oops in unset_pnfs_layoutdriver.
because nfss-&gt;pnfs_curr_ld-&gt;clear_layoutdriver is invalid.

reproduce it:
 modprobe  blocklayoutdriver
 mount -t nfs4 -o minorversion=1 pnfsip:/ /mnt/
 rmmod blocklayoutdriver
 umount /mnt

then you can see following

CPU 0
Pid: 17023, comm: umount.nfs4 Tainted: GF          O 3.7.0-rc6-pnfs #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
RIP: 0010:[&lt;ffffffffa04cfe6d&gt;]  [&lt;ffffffffa04cfe6d&gt;] unset_pnfs_layoutdriver+0x1d/0x70 [nfsv4]
RSP: 0018:ffff8800022d9e48  EFLAGS: 00010286
RAX: ffffffffa04a1b00 RBX: ffff88000b013800 RCX: 0000000000000001
RDX: ffffffff81ae8ee0 RSI: ffff880001ee94b8 RDI: ffff88000b013800
RBP: ffff8800022d9e58 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff880001ee9400
R13: ffff8800105978c0 R14: 00007fff25846c08 R15: 0000000001bba550
FS:  00007f45ae7f0700(0000) GS:ffff880012c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffffffffa04a1b38 CR3: 0000000002c0c000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process umount.nfs4 (pid: 17023, threadinfo ffff8800022d8000, task ffff880006e48aa0)
Stack:
ffff8800105978c0 ffff88000b013800 ffff8800022d9e78 ffffffffa04cd0ce
ffff8800022d9e78 ffff88000b013800 ffff8800022d9ea8 ffffffffa04755a7
ffff8800022d9ea8 ffff880002f96400 ffff88000b013800 ffff880002f96400
Call Trace:
[&lt;ffffffffa04cd0ce&gt;] nfs4_destroy_server+0x1e/0x30 [nfsv4]
[&lt;ffffffffa04755a7&gt;] nfs_free_server+0xb7/0x150 [nfs]
[&lt;ffffffffa047d4d5&gt;] nfs_kill_super+0x35/0x40 [nfs]
[&lt;ffffffff81178d35&gt;] deactivate_locked_super+0x45/0x70
[&lt;ffffffff8117986a&gt;] deactivate_super+0x4a/0x70
[&lt;ffffffff81193ee2&gt;] mntput_no_expire+0xd2/0x130
[&lt;ffffffff81194d62&gt;] sys_umount+0x72/0xe0
[&lt;ffffffff8154af59&gt;] system_call_fastpath+0x16/0x1b
Code: 06 e1 b8 ea ff ff ff eb 9e 0f 1f 44 00 00 55 48 89 e5 53 48 83 ec 08 66 66 66 66 90 48 8b 87 80 03 00 00 48 89 fb 48 85 c0 74 29 &lt;48&gt; 8b 40 38 48 85 c0 74 02 ff d0 48 8b 03 3e ff 48 04 0f 94 c2
RIP  [&lt;ffffffffa04cfe6d&gt;] unset_pnfs_layoutdriver+0x1d/0x70 [nfsv4]
RSP &lt;ffff8800022d9e48&gt;
CR2: ffffffffa04a1b38
---[ end trace 29f75aaedda058bf ]---

Signed-off-by: fanchaoting&lt;fanchaoting@cn.fujitsu.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5a12cca697aca5dfba42a7d4c3356acc0445a2b0 upstream.

now pnfs client uses block layout, maybe we can remove
blocklayoutdriver first. if we umount later,
it can cause oops in unset_pnfs_layoutdriver.
because nfss-&gt;pnfs_curr_ld-&gt;clear_layoutdriver is invalid.

reproduce it:
 modprobe  blocklayoutdriver
 mount -t nfs4 -o minorversion=1 pnfsip:/ /mnt/
 rmmod blocklayoutdriver
 umount /mnt

then you can see following

CPU 0
Pid: 17023, comm: umount.nfs4 Tainted: GF          O 3.7.0-rc6-pnfs #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
RIP: 0010:[&lt;ffffffffa04cfe6d&gt;]  [&lt;ffffffffa04cfe6d&gt;] unset_pnfs_layoutdriver+0x1d/0x70 [nfsv4]
RSP: 0018:ffff8800022d9e48  EFLAGS: 00010286
RAX: ffffffffa04a1b00 RBX: ffff88000b013800 RCX: 0000000000000001
RDX: ffffffff81ae8ee0 RSI: ffff880001ee94b8 RDI: ffff88000b013800
RBP: ffff8800022d9e58 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff880001ee9400
R13: ffff8800105978c0 R14: 00007fff25846c08 R15: 0000000001bba550
FS:  00007f45ae7f0700(0000) GS:ffff880012c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffffffffa04a1b38 CR3: 0000000002c0c000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process umount.nfs4 (pid: 17023, threadinfo ffff8800022d8000, task ffff880006e48aa0)
Stack:
ffff8800105978c0 ffff88000b013800 ffff8800022d9e78 ffffffffa04cd0ce
ffff8800022d9e78 ffff88000b013800 ffff8800022d9ea8 ffffffffa04755a7
ffff8800022d9ea8 ffff880002f96400 ffff88000b013800 ffff880002f96400
Call Trace:
[&lt;ffffffffa04cd0ce&gt;] nfs4_destroy_server+0x1e/0x30 [nfsv4]
[&lt;ffffffffa04755a7&gt;] nfs_free_server+0xb7/0x150 [nfs]
[&lt;ffffffffa047d4d5&gt;] nfs_kill_super+0x35/0x40 [nfs]
[&lt;ffffffff81178d35&gt;] deactivate_locked_super+0x45/0x70
[&lt;ffffffff8117986a&gt;] deactivate_super+0x4a/0x70
[&lt;ffffffff81193ee2&gt;] mntput_no_expire+0xd2/0x130
[&lt;ffffffff81194d62&gt;] sys_umount+0x72/0xe0
[&lt;ffffffff8154af59&gt;] system_call_fastpath+0x16/0x1b
Code: 06 e1 b8 ea ff ff ff eb 9e 0f 1f 44 00 00 55 48 89 e5 53 48 83 ec 08 66 66 66 66 90 48 8b 87 80 03 00 00 48 89 fb 48 85 c0 74 29 &lt;48&gt; 8b 40 38 48 85 c0 74 02 ff d0 48 8b 03 3e ff 48 04 0f 94 c2
RIP  [&lt;ffffffffa04cfe6d&gt;] unset_pnfs_layoutdriver+0x1d/0x70 [nfsv4]
RSP &lt;ffff8800022d9e48&gt;
CR2: ffffffffa04a1b38
---[ end trace 29f75aaedda058bf ]---

Signed-off-by: fanchaoting&lt;fanchaoting@cn.fujitsu.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>NFSv4.1: Declare osd_pri_2_pnfs_err(), objio_init_read/write to be static</title>
<updated>2012-10-16T16:38:00+00:00</updated>
<author>
<name>Trond Myklebust</name>
<email>Trond.Myklebust@netapp.com</email>
</author>
<published>2012-10-16T16:34:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2e928e4878fbc6328c2b1fc897d008db257bfbb0'/>
<id>2e928e4878fbc6328c2b1fc897d008db257bfbb0</id>
<content type='text'>
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>NFS41: send real write size in layoutget</title>
<updated>2012-10-08T23:32:22+00:00</updated>
<author>
<name>Peng Tao</name>
<email>bergwolf@gmail.com</email>
</author>
<published>2012-09-25T06:55:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6296556f0b31eaff29f2a3aee2c17b7eae895b98'/>
<id>6296556f0b31eaff29f2a3aee2c17b7eae895b98</id>
<content type='text'>
For buffer write, block layout client scan inode mapping to find
next hole and use offset-to-hole as layoutget length. Object
layout client uses offset-to-isize as layoutget length.

For direct write, both block layout and object layout use dreq-&gt;bytes_left.

Signed-off-by: Peng Tao &lt;tao.peng@emc.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
For buffer write, block layout client scan inode mapping to find
next hole and use offset-to-hole as layoutget length. Object
layout client uses offset-to-isize as layoutget length.

For direct write, both block layout and object layout use dreq-&gt;bytes_left.

Signed-off-by: Peng Tao &lt;tao.peng@emc.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pnfs-obj: Better IO pattern in case of unaligned offset</title>
<updated>2012-08-02T21:42:51+00:00</updated>
<author>
<name>Boaz Harrosh</name>
<email>bharrosh@panasas.com</email>
</author>
<published>2012-08-02T12:38:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7de6e28417c65919cf2c1621841a650c4a3afbbd'/>
<id>7de6e28417c65919cf2c1621841a650c4a3afbbd</id>
<content type='text'>
Depending on layout and ARCH, ORE has some limits on max IO sizes
which is communicated on (what else) ore_layout-&gt;max_io_length,
which is always stripe aligned.
This was considered as the pg_test boundary for splitting and starting
a new IO.

But in the case of a long IO where the start offset is not aligned
what would happen is that both end of IO[N] and start of IO[N+1]
would be unaligned, causing each IO boundary parity unit to be
calculated and written twice.

So what we do in this patch is split the very start of an unaligned
IO, up to a stripe boundary, and then next IO's can continue fully
aligned til the end.

We might be sacrificing the case where the full unaligned IO would
fit within a single max_io_length, but the sacrifice is well worth
the elimination of double calculation and parity units IO.
Actually the sacrificing is marginal and is almost unmeasurable.

TODO:
	If we know the total expected linear segment that will
	be received, at pg_init, we could use that information
	in many places:
	1. blocks-layout get_layout write segment size
	2. Better mds-threshold
	3. In above situation for a better clean split

	I will do this in future submission.

Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Depending on layout and ARCH, ORE has some limits on max IO sizes
which is communicated on (what else) ore_layout-&gt;max_io_length,
which is always stripe aligned.
This was considered as the pg_test boundary for splitting and starting
a new IO.

But in the case of a long IO where the start offset is not aligned
what would happen is that both end of IO[N] and start of IO[N+1]
would be unaligned, causing each IO boundary parity unit to be
calculated and written twice.

So what we do in this patch is split the very start of an unaligned
IO, up to a stripe boundary, and then next IO's can continue fully
aligned til the end.

We might be sacrificing the case where the full unaligned IO would
fit within a single max_io_length, but the sacrifice is well worth
the elimination of double calculation and parity units IO.
Actually the sacrificing is marginal and is almost unmeasurable.

TODO:
	If we know the total expected linear segment that will
	be received, at pg_init, we could use that information
	in many places:
	1. blocks-layout get_layout write segment size
	2. Better mds-threshold
	3. In above situation for a better clean split

	I will do this in future submission.

Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pnfs-obj: Fix __r4w_get_page when offset is beyond i_size</title>
<updated>2012-07-20T08:50:31+00:00</updated>
<author>
<name>Boaz Harrosh</name>
<email>bharrosh@panasas.com</email>
</author>
<published>2012-06-07T23:02:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c999ff68029ebd0f56ccae75444f640f6d5a27d2'/>
<id>c999ff68029ebd0f56ccae75444f640f6d5a27d2</id>
<content type='text'>
It is very common for the end of the file to be unaligned on
stripe size. But since we know it's beyond file's end then
the XOR should be preformed with all zeros.

Old code used to just read zeros out of the OSD devices, which is a great
waist. But what scares me more about this situation is that, we now have
pages attached to the file's mapping that are beyond i_size. I don't
like the kind of bugs this calls for.

Fix both birds, by returning a global zero_page, if offset is beyond
i_size.

TODO:
	Change the API to -&gt;__r4w_get_page() so a NULL can be
	returned without being considered as error, since XOR API
	treats NULL entries as zero_pages.

[Bug since 3.2. Should apply the same way to all Kernels since]
CC: Stable Tree &lt;stable@kernel.org&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It is very common for the end of the file to be unaligned on
stripe size. But since we know it's beyond file's end then
the XOR should be preformed with all zeros.

Old code used to just read zeros out of the OSD devices, which is a great
waist. But what scares me more about this situation is that, we now have
pages attached to the file's mapping that are beyond i_size. I don't
like the kind of bugs this calls for.

Fix both birds, by returning a global zero_page, if offset is beyond
i_size.

TODO:
	Change the API to -&gt;__r4w_get_page() so a NULL can be
	returned without being considered as error, since XOR API
	treats NULL entries as zero_pages.

[Bug since 3.2. Should apply the same way to all Kernels since]
CC: Stable Tree &lt;stable@kernel.org&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pnfs-obj: don't leak objio_state if ore_write/read fails</title>
<updated>2012-07-20T08:50:30+00:00</updated>
<author>
<name>Boaz Harrosh</name>
<email>bharrosh@panasas.com</email>
</author>
<published>2012-06-08T02:29:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9909d45a8557455ca5f8ee7af0f253debc851f1a'/>
<id>9909d45a8557455ca5f8ee7af0f253debc851f1a</id>
<content type='text'>
[Bug since 3.2 Kernel]
CC: Stable Tree &lt;stable@kernel.org&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[Bug since 3.2 Kernel]
CC: Stable Tree &lt;stable@kernel.org&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>NFS: Fix sparse warnings</title>
<updated>2012-05-04T18:59:51+00:00</updated>
<author>
<name>Trond Myklebust</name>
<email>Trond.Myklebust@netapp.com</email>
</author>
<published>2012-05-04T17:54:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1385b8117325e79f74c1e7d1cbf45c789deb85c5'/>
<id>1385b8117325e79f74c1e7d1cbf45c789deb85c5</id>
<content type='text'>
Fix the following sparse warnings:

fs/nfs/direct.c:221:6: warning: symbol 'nfs_direct_readpage_release' was
not declared. Should it be static?
fs/nfs/read.c:38:43: warning: non-ANSI function declaration of function
'nfs_readhdr_alloc'
fs/nfs/objlayout/objio_osd.c:214:5: warning: symbol '__alloc_objio_seg'
was not declared. Should it be static?

Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
Cc: Fred Isaman &lt;iisaman@netapp.com&gt;
Cc: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix the following sparse warnings:

fs/nfs/direct.c:221:6: warning: symbol 'nfs_direct_readpage_release' was
not declared. Should it be static?
fs/nfs/read.c:38:43: warning: non-ANSI function declaration of function
'nfs_readhdr_alloc'
fs/nfs/objlayout/objio_osd.c:214:5: warning: symbol '__alloc_objio_seg'
was not declared. Should it be static?

Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
Cc: Fred Isaman &lt;iisaman@netapp.com&gt;
Cc: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>NFS: create common nfs_pgio_header for both read and write</title>
<updated>2012-04-27T18:10:37+00:00</updated>
<author>
<name>Fred Isaman</name>
<email>iisaman@netapp.com</email>
</author>
<published>2012-04-20T18:47:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cd841605f7a721878d8a2d1362484723d8abf569'/>
<id>cd841605f7a721878d8a2d1362484723d8abf569</id>
<content type='text'>
In order to avoid duplicating all the data in nfs_read_data whenever we
split it up into multiple RPC calls (either due to a short read result
or due to rsize &lt; PAGE_SIZE), we split out the bits that are the same
per RPC call into a separate "header" structure.

The goal this patch moves towards is to have a single header
refcounted by several rpc_data structures.  Thus, want to always refer
from rpc_data to the header, and not the other way.  This patch comes
close to that ideal, but the directio code currently needs some
special casing, isolated in the nfs_direct_[read_write]hdr_release()
functions.  This will be dealt with in a future patch.

Signed-off-by: Fred Isaman &lt;iisaman@netapp.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In order to avoid duplicating all the data in nfs_read_data whenever we
split it up into multiple RPC calls (either due to a short read result
or due to rsize &lt; PAGE_SIZE), we split out the bits that are the same
per RPC call into a separate "header" structure.

The goal this patch moves towards is to have a single header
refcounted by several rpc_data structures.  Thus, want to always refer
from rpc_data to the header, and not the other way.  This patch comes
close to that ideal, but the directio code currently needs some
special casing, isolated in the nfs_direct_[read_write]hdr_release()
functions.  This will be dealt with in a future patch.

Signed-off-by: Fred Isaman &lt;iisaman@netapp.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pnfs-obj: Remove unused variable from objlayout_get_deviceinfo()</title>
<updated>2012-04-26T16:15:51+00:00</updated>
<author>
<name>Sachin Bhamare</name>
<email>sbhamare@panasas.com</email>
</author>
<published>2012-03-30T21:29:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9526b2b6d6b9f183b66cf21c4afa6e79d5a14f44'/>
<id>9526b2b6d6b9f183b66cf21c4afa6e79d5a14f44</id>
<content type='text'>
Local variable 'sb' was not being used in objlayout_get_deviceinfo().

Signed-off-by: Sachin Bhamare &lt;sbhamare@panasas.com&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Local variable 'sb' was not being used in objlayout_get_deviceinfo().

Signed-off-by: Sachin Bhamare &lt;sbhamare@panasas.com&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pnfs-obj: autologin: Add support for protocol autologin</title>
<updated>2012-03-21T13:31:47+00:00</updated>
<author>
<name>Sachin Bhamare</name>
<email>sbhamare@panasas.com</email>
</author>
<published>2012-03-20T03:47:58+00:00</published>
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<id>18d98f6c04991dd3c12acf6f39cea40e9510640a</id>
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The pnfs-objects protocol mandates that we autologin into devices not
present in the system, according to information specified in the
get_device_info returned from the server.

The Protocol specifies two login hints.
1. An IP address:port combination
2. A string URI which is constructed as a URL with a protocol prefix
   followed by :// and a string as address. For each  protocol prefix
   the string-address format might be different.

We only support the second option. The first option is just redundant
to the second one.
NOTE: The Kernel part of autologin does not parse the URI string. It
just channels it to a user-mode script. So any new login protocols should
only update the user-mode script which is a part of the nfs-utils package,
but the Kernel need not change.

We implement the autologin by using the call_usermodehelper() API.
(Thanks to Steve Dickson &lt;steved@redhat.com&gt; for pointing it out)
So there is no running daemon needed, and/or special setup.

We Add the osd_login_prog Kernel module parameters which defaults to:
	/sbin/osd_login

Kernel try's to upcall the program specified in osd_login_prog. If the file is
not found or the execution fails Kernel will disable any farther upcalls, by
zeroing out  osd_login_prog, Until Admin re-enables it by setting the
osd_login_prog parameter to a proper program.

Also add text about the osd_login program command line API to:
	Documentation/filesystems/nfs/pnfs.txt
and documentation of the new  osd_login_prog  module parameter to:
	Documentation/kernel-parameters.txt

TODO: Add timeout option in the case osd_login program gets
              stuck

Signed-off-by: Sachin Bhamare &lt;sbhamare@panasas.com&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
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<pre>
The pnfs-objects protocol mandates that we autologin into devices not
present in the system, according to information specified in the
get_device_info returned from the server.

The Protocol specifies two login hints.
1. An IP address:port combination
2. A string URI which is constructed as a URL with a protocol prefix
   followed by :// and a string as address. For each  protocol prefix
   the string-address format might be different.

We only support the second option. The first option is just redundant
to the second one.
NOTE: The Kernel part of autologin does not parse the URI string. It
just channels it to a user-mode script. So any new login protocols should
only update the user-mode script which is a part of the nfs-utils package,
but the Kernel need not change.

We implement the autologin by using the call_usermodehelper() API.
(Thanks to Steve Dickson &lt;steved@redhat.com&gt; for pointing it out)
So there is no running daemon needed, and/or special setup.

We Add the osd_login_prog Kernel module parameters which defaults to:
	/sbin/osd_login

Kernel try's to upcall the program specified in osd_login_prog. If the file is
not found or the execution fails Kernel will disable any farther upcalls, by
zeroing out  osd_login_prog, Until Admin re-enables it by setting the
osd_login_prog parameter to a proper program.

Also add text about the osd_login program command line API to:
	Documentation/filesystems/nfs/pnfs.txt
and documentation of the new  osd_login_prog  module parameter to:
	Documentation/kernel-parameters.txt

TODO: Add timeout option in the case osd_login program gets
              stuck

Signed-off-by: Sachin Bhamare &lt;sbhamare@panasas.com&gt;
Signed-off-by: Boaz Harrosh &lt;bharrosh@panasas.com&gt;
Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
</pre>
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