<feed xmlns='http://www.w3.org/2005/Atom'>
<title>glusterfs.git/xlators/cluster/afr/src, branch v3.5.0</title>
<subtitle></subtitle>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/'/>
<entry>
<title>glusterd/geo-rep: more glusterd and cli fixes for geo-rep.</title>
<updated>2014-01-27T17:44:33+00:00</updated>
<author>
<name>Ajeet Jha</name>
<email>ajha@redhat.com</email>
</author>
<published>2013-12-02T07:25:18+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=f33d09f23b089bd07437eb714f8dffa43460d6b5'/>
<id>f33d09f23b089bd07437eb714f8dffa43460d6b5</id>
<content type='text'>
    -&gt; handle option validation cases in reset case.
    -&gt; Creating valid conf path when glusterd restarts.
    -&gt; Reading the gsyncd worker thread status and displaying it.
    -&gt; Displaying status-detail per worker.
    -&gt; Fetch checkpoint info in geo-rep status.
    -&gt; use-tarssh value validation added.

misc: misc geo-rep fixes based on cluster, logrotate etc..
    -&gt; cluster/dht: fix 'stime' getxattr getting overwritten.
    -&gt; cluster/afr: return max of 'stime' values in subvol.
    -&gt; geo-rep-logrotate: Sending SIGHUP to geo-rep auxiliary.
    -&gt; cluster/dht: fix convoluted logic while aggregating.
    -&gt; cluster/*: fix 'stime' min/max fetch logic.

Change-Id: I811acea0bbd6194797a3e55d89295d1ea021ac85
BUG: 1036552
Signed-off-by: Ajeet Jha &lt;ajha@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6405
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Amar Tumballi &lt;amarts@gmail.com&gt;
Reviewed-by: Anand Avati &lt;avati@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6810
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
    -&gt; handle option validation cases in reset case.
    -&gt; Creating valid conf path when glusterd restarts.
    -&gt; Reading the gsyncd worker thread status and displaying it.
    -&gt; Displaying status-detail per worker.
    -&gt; Fetch checkpoint info in geo-rep status.
    -&gt; use-tarssh value validation added.

misc: misc geo-rep fixes based on cluster, logrotate etc..
    -&gt; cluster/dht: fix 'stime' getxattr getting overwritten.
    -&gt; cluster/afr: return max of 'stime' values in subvol.
    -&gt; geo-rep-logrotate: Sending SIGHUP to geo-rep auxiliary.
    -&gt; cluster/dht: fix convoluted logic while aggregating.
    -&gt; cluster/*: fix 'stime' min/max fetch logic.

Change-Id: I811acea0bbd6194797a3e55d89295d1ea021ac85
BUG: 1036552
Signed-off-by: Ajeet Jha &lt;ajha@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6405
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Amar Tumballi &lt;amarts@gmail.com&gt;
Reviewed-by: Anand Avati &lt;avati@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6810
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cluster/afr: Treat ESTALE on nameless lookup as ENOENT</title>
<updated>2014-01-27T17:17:38+00:00</updated>
<author>
<name>Pranith Kumar K</name>
<email>pkarampu@redhat.com</email>
</author>
<published>2013-12-26T06:01:49+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=cc1728766620e13ccfe2cd0b162cbc848b20e422'/>
<id>cc1728766620e13ccfe2cd0b162cbc848b20e422</id>
<content type='text'>
Change-Id: I635fc0fa955b33590f1c5b4dfec22d591ea8575c
BUG: 1032894
Signed-off-by: Pranith Kumar K &lt;pkarampu@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6593
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Change-Id: I635fc0fa955b33590f1c5b4dfec22d591ea8575c
BUG: 1032894
Signed-off-by: Pranith Kumar K &lt;pkarampu@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6593
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cluster/afr: Treat FOOL condition as split-brain for entry self-heal</title>
<updated>2014-01-25T18:42:00+00:00</updated>
<author>
<name>Pranith Kumar K</name>
<email>pkarampu@redhat.com</email>
</author>
<published>2014-01-25T05:13:52+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=aa1c0e7f855504c3c7dc6890ada451385a6c523e'/>
<id>aa1c0e7f855504c3c7dc6890ada451385a6c523e</id>
<content type='text'>
Change-Id: I44c942d5f949ea812d66184f868471522db17027
BUG: 1057846
Signed-off-by: Pranith Kumar K &lt;pkarampu@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6789
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Ravishankar N &lt;ravishankar@redhat.com&gt;
Reviewed-by: Anand Avati &lt;avati@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Change-Id: I44c942d5f949ea812d66184f868471522db17027
BUG: 1057846
Signed-off-by: Pranith Kumar K &lt;pkarampu@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6789
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Ravishankar N &lt;ravishankar@redhat.com&gt;
Reviewed-by: Anand Avati &lt;avati@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cluster/afr:  Change errno to op_errno</title>
<updated>2013-12-30T07:16:33+00:00</updated>
<author>
<name>Venkatesh Somyajulu</name>
<email>vsomyaju@redhat.com</email>
</author>
<published>2013-12-19T12:34:46+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=a3e3e8dee442371665996450ac3a8d2859c47cc0'/>
<id>a3e3e8dee442371665996450ac3a8d2859c47cc0</id>
<content type='text'>
Changed errno to op_errno

Change-Id: I357987af352cf1d9abda4188d392f17d10b12aec
BUG: 1037501
Signed-off-by: Venkatesh Somyajulu &lt;vsomyaju@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6541
Reviewed-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Changed errno to op_errno

Change-Id: I357987af352cf1d9abda4188d392f17d10b12aec
BUG: 1037501
Signed-off-by: Venkatesh Somyajulu &lt;vsomyaju@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6541
Reviewed-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cluster/afr: For entry self heal, mark all source bricks</title>
<updated>2013-12-19T11:44:45+00:00</updated>
<author>
<name>Venkatesh Somyajulu</name>
<email>vsomyaju@redhat.com</email>
</author>
<published>2013-12-16T13:34:54+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=7683a4bed9d3168f9a6e70af1a7e316334b201cb'/>
<id>7683a4bed9d3168f9a6e70af1a7e316334b201cb</id>
<content type='text'>
Problem:
Whenever a new brick is added into a replicate volume, all
source bricks are not marked as source. Only one of them is
marked as source. Here marked as source refers to adding
extended attribute at the backend of a file corresponding to
the newly added brick. As well as source bricks should point
to the newly added brick so that heal can be triggered.

Fix:
All source bricks will now point to newly added bricks and heal
can be triggered based on the extended attributes.

Change-Id: Ia7cf118270fecc429bdecddbcb9201f23fedc7a1
BUG: 1037501
Signed-off-by: Venkatesh Somyajulu &lt;vsomyaju@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6419
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
Reviewed-by: Ravishankar N &lt;ravishankar@redhat.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Problem:
Whenever a new brick is added into a replicate volume, all
source bricks are not marked as source. Only one of them is
marked as source. Here marked as source refers to adding
extended attribute at the backend of a file corresponding to
the newly added brick. As well as source bricks should point
to the newly added brick so that heal can be triggered.

Fix:
All source bricks will now point to newly added bricks and heal
can be triggered based on the extended attributes.

Change-Id: Ia7cf118270fecc429bdecddbcb9201f23fedc7a1
BUG: 1037501
Signed-off-by: Venkatesh Somyajulu &lt;vsomyaju@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6419
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
Reviewed-by: Ravishankar N &lt;ravishankar@redhat.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cluster/afr: handle NULL check before strlen/strcmp in fgetxattr</title>
<updated>2013-12-05T05:12:50+00:00</updated>
<author>
<name>Anand Avati</name>
<email>avati@redhat.com</email>
</author>
<published>2013-11-27T18:35:30+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=550d83889857c1fe2c8eb04b1740a4884db7697d'/>
<id>550d83889857c1fe2c8eb04b1740a4884db7697d</id>
<content type='text'>
xattr name can legally be NULL. Handle that case without crashing.

Change-Id: Ie214cb05ccd52565dc247a9234ad83ae799d3866
BUG: 1036879
Signed-off-by: Anand Avati &lt;avati@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6422
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
xattr name can legally be NULL. Handle that case without crashing.

Change-Id: Ie214cb05ccd52565dc247a9234ad83ae799d3866
BUG: 1036879
Signed-off-by: Anand Avati &lt;avati@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6422
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>core: fix errno for non-existent GFID</title>
<updated>2013-11-26T18:29:23+00:00</updated>
<author>
<name>Anand Avati</name>
<email>avati@redhat.com</email>
</author>
<published>2013-11-21T14:48:17+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=d1879d04e39258ea25a49eed3244b395d4af2c1d'/>
<id>d1879d04e39258ea25a49eed3244b395d4af2c1d</id>
<content type='text'>
When clients refer to a GFID which does not exist, the errno to
be returned in ESTALE (and not ENOENT). Even though ENOENT might
look "proper" most of the time, as the application eventually expects
ENOENT even if a parent directory does not exist, not returning
ESTALE results in resolvers (FUSE and GFAPI) to not retry resolution
in uncached mode. This can result in spurious ENOENTs during
concurrent path modification operations.

Change-Id: I7a06ea6d6a191739f2e9c6e333a1969615e05936
BUG: 1032894
Signed-off-by: Anand Avati &lt;avati@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6318
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Amar Tumballi &lt;amarts@gmail.com&gt;
Reviewed-by: Brian Foster &lt;bfoster@redhat.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When clients refer to a GFID which does not exist, the errno to
be returned in ESTALE (and not ENOENT). Even though ENOENT might
look "proper" most of the time, as the application eventually expects
ENOENT even if a parent directory does not exist, not returning
ESTALE results in resolvers (FUSE and GFAPI) to not retry resolution
in uncached mode. This can result in spurious ENOENTs during
concurrent path modification operations.

Change-Id: I7a06ea6d6a191739f2e9c6e333a1969615e05936
BUG: 1032894
Signed-off-by: Anand Avati &lt;avati@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6318
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Amar Tumballi &lt;amarts@gmail.com&gt;
Reviewed-by: Brian Foster &lt;bfoster@redhat.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cluster/afr: Provide HA for pathinfo getxattr</title>
<updated>2013-11-26T08:34:14+00:00</updated>
<author>
<name>Pranith Kumar K</name>
<email>pkarampu@redhat.com</email>
</author>
<published>2013-11-21T10:47:32+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=1d554b179f63a5a56ae447f2a5b0044c49ae2642'/>
<id>1d554b179f63a5a56ae447f2a5b0044c49ae2642</id>
<content type='text'>
Problem:
afr_[f]getxattr_pathinfo_cbks fail the fop even when it succeeded on
one of the bricks. This can happen if the last response to pathinfo
[f]getxattr is a failure.

Fix:
Remember if any of the [f]getxattr_pathinfos are successful and send
that as the op_ret/op_errno value to the xlators above.

Note:
Winding fop to a client xlator that is not connected to server produces
an error log. Preventing that by not even winding fop when client xlator
is DOWN.

Change-Id: I846e8c47423ffcfa2eabffe8924534781a36841a
BUG: 1032927
Signed-off-by: Pranith Kumar K &lt;pkarampu@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6332
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Problem:
afr_[f]getxattr_pathinfo_cbks fail the fop even when it succeeded on
one of the bricks. This can happen if the last response to pathinfo
[f]getxattr is a failure.

Fix:
Remember if any of the [f]getxattr_pathinfos are successful and send
that as the op_ret/op_errno value to the xlators above.

Note:
Winding fop to a client xlator that is not connected to server produces
an error log. Preventing that by not even winding fop when client xlator
is DOWN.

Change-Id: I846e8c47423ffcfa2eabffe8924534781a36841a
BUG: 1032927
Signed-off-by: Pranith Kumar K &lt;pkarampu@redhat.com&gt;
Reviewed-on: http://review.gluster.org/6332
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>zerofill: Change the type of len argument of glfs_zerofill() to off_t</title>
<updated>2013-11-15T07:29:48+00:00</updated>
<author>
<name>Bharata B Rao</name>
<email>bharata@linux.vnet.ibm.com</email>
</author>
<published>2013-11-15T04:41:58+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=884a668a9c3e12e17d64ebd5ccd9fbf3d203fd1e'/>
<id>884a668a9c3e12e17d64ebd5ccd9fbf3d203fd1e</id>
<content type='text'>
glfs_zerofill() can be potentially called to zero-out entire file and
hence allow for bigger value of length parameter.

Change-Id: I75f1d11af298915049a3f3a7cb3890a2d72fca63
BUG: 1028673
Signed-off-by: Bharata B Rao &lt;bharata@linux.vnet.ibm.com&gt;
Reviewed-on: http://review.gluster.org/6266
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: M. Mohan Kumar &lt;mohan@in.ibm.com&gt;
Tested-by: M. Mohan Kumar &lt;mohan@in.ibm.com&gt;
Reviewed-by: Anand Avati &lt;avati@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
glfs_zerofill() can be potentially called to zero-out entire file and
hence allow for bigger value of length parameter.

Change-Id: I75f1d11af298915049a3f3a7cb3890a2d72fca63
BUG: 1028673
Signed-off-by: Bharata B Rao &lt;bharata@linux.vnet.ibm.com&gt;
Reviewed-on: http://review.gluster.org/6266
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: M. Mohan Kumar &lt;mohan@in.ibm.com&gt;
Tested-by: M. Mohan Kumar &lt;mohan@in.ibm.com&gt;
Reviewed-by: Anand Avati &lt;avati@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>glusterfs: zerofill support</title>
<updated>2013-11-11T05:25:49+00:00</updated>
<author>
<name>M. Mohan Kumar</name>
<email>mohan@in.ibm.com</email>
</author>
<published>2013-11-09T09:21:53+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=c8fef37c5d566c906728b5f6f27baaa9a8d2a20d'/>
<id>c8fef37c5d566c906728b5f6f27baaa9a8d2a20d</id>
<content type='text'>
Add support for a new ZEROFILL fop. Zerofill writes zeroes to a file in
the specified range. This fop will be useful when a whole file needs to
be initialized with zero (could be useful for zero filled VM disk image
provisioning or  during scrubbing of VM disk images).

Client/application can issue this FOP for zeroing out. Gluster server
will zero out required range of bytes ie server offloaded zeroing. In
the absence of this fop,  client/application has to repetitively issue
write (zero) fop to the server, which is very inefficient method because
of the overheads involved in RPC calls  and acknowledgements.

WRITESAME is a  SCSI T10 command that takes a block of data as input and
writes the same data to other blocks and this write is handled
completely within the storage and hence is known as offload . Linux ,now
has support for SCSI WRITESAME command which is exposed to the user in
the form of BLKZEROOUT ioctl.  BD Xlator can exploit BLKZEROOUT ioctl to
implement this fop. Thus zeroing out operations can be completely
offloaded to the storage device , making it highly efficient.

The fop takes two arguments offset and size. It zeroes out 'size' number
of bytes in an opened file starting from 'offset' position.

This patch adds zerofill support to the following areas:
	- libglusterfs
	- io-stats
	- performance/md-cache,open-behind
	- quota
	- cluster/afr,dht,stripe
	- rpc/xdr
	- protocol/client,server
	- io-threads
	- marker
	- storage/posix
	- libgfapi

Client applications can exloit this fop by using glfs_zerofill introduced in
libgfapi.FUSE support to this fop has not been added as there is no system call
for this fop.

Changes from previous version 3:
* Removed redundant memory failure log messages

Changes from previous version 2:
* Rebased and fixed build error

Changes from previous version 1:
* Rebased for latest master

TODO :
     * Add zerofill support to trace xlator
     * Expose zerofill capability as part of gluster volume info

Here is a performance comparison of server offloaded zeofill vs zeroing
out using repeated writes.

[root@llmvm02 remote]# time ./offloaded aakash-test log 20

real	3m34.155s
user	0m0.018s
sys	0m0.040s
[root@llmvm02 remote]# time ./manually aakash-test log 20

real	4m23.043s
user	0m2.197s
sys	0m14.457s
[root@llmvm02 remote]# time ./offloaded aakash-test log 25;

real	4m28.363s
user	0m0.021s
sys	0m0.025s
[root@llmvm02 remote]# time ./manually aakash-test log 25

real	5m34.278s
user	0m2.957s
sys	0m18.808s

The argument log is a file which we want to set for logging purpose and
the third argument is size in GB .

As we can see there is a performance improvement of around 20% with this
fop.

Change-Id: I081159f5f7edde0ddb78169fb4c21c776ec91a18
BUG: 1028673
Signed-off-by: Aakash Lal Das &lt;aakash@linux.vnet.ibm.com&gt;
Signed-off-by: M. Mohan Kumar &lt;mohan@in.ibm.com&gt;
Reviewed-on: http://review.gluster.org/5327
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
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Add support for a new ZEROFILL fop. Zerofill writes zeroes to a file in
the specified range. This fop will be useful when a whole file needs to
be initialized with zero (could be useful for zero filled VM disk image
provisioning or  during scrubbing of VM disk images).

Client/application can issue this FOP for zeroing out. Gluster server
will zero out required range of bytes ie server offloaded zeroing. In
the absence of this fop,  client/application has to repetitively issue
write (zero) fop to the server, which is very inefficient method because
of the overheads involved in RPC calls  and acknowledgements.

WRITESAME is a  SCSI T10 command that takes a block of data as input and
writes the same data to other blocks and this write is handled
completely within the storage and hence is known as offload . Linux ,now
has support for SCSI WRITESAME command which is exposed to the user in
the form of BLKZEROOUT ioctl.  BD Xlator can exploit BLKZEROOUT ioctl to
implement this fop. Thus zeroing out operations can be completely
offloaded to the storage device , making it highly efficient.

The fop takes two arguments offset and size. It zeroes out 'size' number
of bytes in an opened file starting from 'offset' position.

This patch adds zerofill support to the following areas:
	- libglusterfs
	- io-stats
	- performance/md-cache,open-behind
	- quota
	- cluster/afr,dht,stripe
	- rpc/xdr
	- protocol/client,server
	- io-threads
	- marker
	- storage/posix
	- libgfapi

Client applications can exloit this fop by using glfs_zerofill introduced in
libgfapi.FUSE support to this fop has not been added as there is no system call
for this fop.

Changes from previous version 3:
* Removed redundant memory failure log messages

Changes from previous version 2:
* Rebased and fixed build error

Changes from previous version 1:
* Rebased for latest master

TODO :
     * Add zerofill support to trace xlator
     * Expose zerofill capability as part of gluster volume info

Here is a performance comparison of server offloaded zeofill vs zeroing
out using repeated writes.

[root@llmvm02 remote]# time ./offloaded aakash-test log 20

real	3m34.155s
user	0m0.018s
sys	0m0.040s
[root@llmvm02 remote]# time ./manually aakash-test log 20

real	4m23.043s
user	0m2.197s
sys	0m14.457s
[root@llmvm02 remote]# time ./offloaded aakash-test log 25;

real	4m28.363s
user	0m0.021s
sys	0m0.025s
[root@llmvm02 remote]# time ./manually aakash-test log 25

real	5m34.278s
user	0m2.957s
sys	0m18.808s

The argument log is a file which we want to set for logging purpose and
the third argument is size in GB .

As we can see there is a performance improvement of around 20% with this
fop.

Change-Id: I081159f5f7edde0ddb78169fb4c21c776ec91a18
BUG: 1028673
Signed-off-by: Aakash Lal Das &lt;aakash@linux.vnet.ibm.com&gt;
Signed-off-by: M. Mohan Kumar &lt;mohan@in.ibm.com&gt;
Reviewed-on: http://review.gluster.org/5327
Tested-by: Gluster Build System &lt;jenkins@build.gluster.com&gt;
Reviewed-by: Vijay Bellur &lt;vbellur@redhat.com&gt;
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