<feed xmlns='http://www.w3.org/2005/Atom'>
<title>glusterfs.git/xlators/protocol/client/src/client.c, branch v4.1.0alpha</title>
<subtitle></subtitle>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/'/>
<entry>
<title>protocol: Implement put fop</title>
<updated>2018-01-31T09:13:58+00:00</updated>
<author>
<name>Poornima G</name>
<email>pgurusid@redhat.com</email>
</author>
<published>2018-01-16T08:44:39+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=542af5714d761e787276111ca8bf7a5c69afb721'/>
<id>542af5714d761e787276111ca8bf7a5c69afb721</id>
<content type='text'>
Updates #353
Change-Id: I755b9208690be76935d763688fa414521eba3a40
Signed-off-by: Poornima G &lt;pgurusid@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Updates #353
Change-Id: I755b9208690be76935d763688fa414521eba3a40
Signed-off-by: Poornima G &lt;pgurusid@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>quiesce, gfproxy: Implement failover across multiple gfproxy nodes</title>
<updated>2018-01-30T05:00:52+00:00</updated>
<author>
<name>Poornima G</name>
<email>pgurusid@redhat.com</email>
</author>
<published>2018-01-26T10:04:43+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=d25b6065469eb978d40450b5aebcf5711fb50205'/>
<id>d25b6065469eb978d40450b5aebcf5711fb50205</id>
<content type='text'>
Updates: #242
Change-Id: I767e574a26e922760a7130bd209c178d74e8cf69
Signed-off-by: Poornima G &lt;pgurusid@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Updates: #242
Change-Id: I767e574a26e922760a7130bd209c178d74e8cf69
Signed-off-by: Poornima G &lt;pgurusid@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>protocol: Remove lock recovery logic from client and server</title>
<updated>2018-01-29T17:36:31+00:00</updated>
<author>
<name>Anoop C S</name>
<email>anoopcs@redhat.com</email>
</author>
<published>2015-10-15T09:34:34+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=3e78ea991b213422fc423ff94994e1eb295569c7'/>
<id>3e78ea991b213422fc423ff94994e1eb295569c7</id>
<content type='text'>
Change-Id: I27f5e1e34fe3eac96c7dd88e90753fb5d3d14550
BUG: 1272030
Signed-off-by: Anoop C S &lt;anoopcs@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Change-Id: I27f5e1e34fe3eac96c7dd88e90753fb5d3d14550
BUG: 1272030
Signed-off-by: Anoop C S &lt;anoopcs@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>protocol/client: reduce lock contention</title>
<updated>2017-12-26T05:05:55+00:00</updated>
<author>
<name>Zhang Huan</name>
<email>zhanghuan@open-fs.com</email>
</author>
<published>2017-11-29T09:36:55+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=f13023862edc868d4da87609412341aecd041ed8'/>
<id>f13023862edc868d4da87609412341aecd041ed8</id>
<content type='text'>
Current use of a per-client mutex to protect fdctx introduces lock
contentions when there are dozens of file operations active.

Use finer grain spinlock to reduce contention, and put retrieving
fdctx out of lock.

Change-Id: Iea3e2eb481e76a5d73a582ba81529180c5b88248
BUG: 1519598
Signed-off-by: Zhang Huan &lt;zhanghuan@open-fs.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Current use of a per-client mutex to protect fdctx introduces lock
contentions when there are dozens of file operations active.

Use finer grain spinlock to reduce contention, and put retrieving
fdctx out of lock.

Change-Id: Iea3e2eb481e76a5d73a582ba81529180c5b88248
BUG: 1519598
Signed-off-by: Zhang Huan &lt;zhanghuan@open-fs.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>glusterfs: Use gcc builtin ATOMIC operator to increase/decreate refcount.</title>
<updated>2017-12-12T09:05:56+00:00</updated>
<author>
<name>Mohit Agrawal</name>
<email>moagrawa@redhat.com</email>
</author>
<published>2017-10-20T07:09:29+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=430484c92ab5a6234958d1143e0bb14aeb0cd1c0'/>
<id>430484c92ab5a6234958d1143e0bb14aeb0cd1c0</id>
<content type='text'>
Problem: In glusterfs code base we call mutex_lock/unlock to take
         reference/dereference for a object.Sometime it could be
         reason for lock contention also.

Solution: There is no need to use mutex to increase/decrease ref
          counter, instead of using mutex use gcc builtin ATOMIC
          operation.

Test:   I have not observed yet how much performance gain after apply
        this patch specific to glusterfs but i have tested same
        with below small program(mutex and atomic both) and
        get good difference.

static int numOuterLoops;
static void *
threadFunc(void *arg)
{
    int j;

    for (j = 0; j &lt; numOuterLoops; j++) {
            __atomic_add_fetch (&amp;glob, 1,__ATOMIC_ACQ_REL);
    }
    return NULL;
}

int
main(int argc, char *argv[])
{
    int opt, s, j;
    int numThreads;
    pthread_t *thread;
    int verbose;
    int64_t n = 0;

    if (argc &lt; 2 ) {
     printf(" Please provide 2 args Num of threads &amp;&amp; Outer Loop\n");
     exit (-1);
    }
    numThreads = atoi(argv[1]);
    numOuterLoops = atoi (argv[2]);

    if (1) {
        printf("\tthreads: %d; outer loops: %d;\n",
                numThreads, numOuterLoops);
    }

    thread = calloc(numThreads, sizeof(pthread_t));
    if (thread == NULL) {
        printf ("calloc error so exit\n");
        exit (-1);
    }

    __atomic_store (&amp;glob, &amp;n, __ATOMIC_RELEASE);
    for (j = 0; j &lt; numThreads; j++) {
        s = pthread_create(&amp;thread[j], NULL, threadFunc, NULL);
        if (s != 0) {
            printf ("pthread_create failed so exit\n");
            exit (-1);
        }
    }

    for (j = 0; j &lt; numThreads; j++) {
        s = pthread_join(thread[j], NULL);
        if (s != 0) {
            printf ("pthread_join failed so exit\n");
            exit (-1);
        }
    }
    printf("glob value is %ld\n",__atomic_load_n (&amp;glob,__ATOMIC_RELAXED));

    exit(0);
}

   time ./thr_count 800 800000
   threads: 800; outer loops: 800000;
   glob value is 640000000

real	1m10.288s
user	0m57.269s
sys	3m31.565s

time ./thr_count_atomic 800 800000
     threads: 800; outer loops: 800000;
glob value is 640000000

real	0m20.313s
user	1m20.558s
sys	0m0.028

Change-Id: Ie5030a52ea264875e002e108dd4b207b15ab7cc7
Signed-off-by: Mohit Agrawal &lt;moagrawa@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Problem: In glusterfs code base we call mutex_lock/unlock to take
         reference/dereference for a object.Sometime it could be
         reason for lock contention also.

Solution: There is no need to use mutex to increase/decrease ref
          counter, instead of using mutex use gcc builtin ATOMIC
          operation.

Test:   I have not observed yet how much performance gain after apply
        this patch specific to glusterfs but i have tested same
        with below small program(mutex and atomic both) and
        get good difference.

static int numOuterLoops;
static void *
threadFunc(void *arg)
{
    int j;

    for (j = 0; j &lt; numOuterLoops; j++) {
            __atomic_add_fetch (&amp;glob, 1,__ATOMIC_ACQ_REL);
    }
    return NULL;
}

int
main(int argc, char *argv[])
{
    int opt, s, j;
    int numThreads;
    pthread_t *thread;
    int verbose;
    int64_t n = 0;

    if (argc &lt; 2 ) {
     printf(" Please provide 2 args Num of threads &amp;&amp; Outer Loop\n");
     exit (-1);
    }
    numThreads = atoi(argv[1]);
    numOuterLoops = atoi (argv[2]);

    if (1) {
        printf("\tthreads: %d; outer loops: %d;\n",
                numThreads, numOuterLoops);
    }

    thread = calloc(numThreads, sizeof(pthread_t));
    if (thread == NULL) {
        printf ("calloc error so exit\n");
        exit (-1);
    }

    __atomic_store (&amp;glob, &amp;n, __ATOMIC_RELEASE);
    for (j = 0; j &lt; numThreads; j++) {
        s = pthread_create(&amp;thread[j], NULL, threadFunc, NULL);
        if (s != 0) {
            printf ("pthread_create failed so exit\n");
            exit (-1);
        }
    }

    for (j = 0; j &lt; numThreads; j++) {
        s = pthread_join(thread[j], NULL);
        if (s != 0) {
            printf ("pthread_join failed so exit\n");
            exit (-1);
        }
    }
    printf("glob value is %ld\n",__atomic_load_n (&amp;glob,__ATOMIC_RELAXED));

    exit(0);
}

   time ./thr_count 800 800000
   threads: 800; outer loops: 800000;
   glob value is 640000000

real	1m10.288s
user	0m57.269s
sys	3m31.565s

time ./thr_count_atomic 800 800000
     threads: 800; outer loops: 800000;
glob value is 640000000

real	0m20.313s
user	1m20.558s
sys	0m0.028

Change-Id: Ie5030a52ea264875e002e108dd4b207b15ab7cc7
Signed-off-by: Mohit Agrawal &lt;moagrawa@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rio/everywhere: add icreate/namelink fop</title>
<updated>2017-12-05T21:23:57+00:00</updated>
<author>
<name>Susant Palai</name>
<email>spalai@redhat.com</email>
</author>
<published>2017-08-22T08:14:52+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=efad78260379f0ca836e8a2327b97dd620acd098'/>
<id>efad78260379f0ca836e8a2327b97dd620acd098</id>
<content type='text'>
icreate creates inode, while namelink links the basename to it's
parent gfid.

For now mkdir is the primary user of these fops. Better distribution is
acheived by creating the inode on ,(say) mds1 and linking the basename to it's
parent gfid on mds2. The inode serves readdirp, stat etc.

More details about the fops are present at:
https://review.gluster.org/#/c/13395/3/design/DHT2/DHT2_Icreate_Namelink_Notes.md

This backport of three patches from experimental branch.
1- https://review.gluster.org/#/c/18085/
2- https://review.gluster.org/#/c/18086/
3- https://review.gluster.org/#/c/18094/

Updates gluster/glusterfs#243
Change-Id: I1bd3d5a441a3cfab1acfeb52f15c6c867d362592
Signed-off-by: Susant Palai &lt;spalai@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
icreate creates inode, while namelink links the basename to it's
parent gfid.

For now mkdir is the primary user of these fops. Better distribution is
acheived by creating the inode on ,(say) mds1 and linking the basename to it's
parent gfid on mds2. The inode serves readdirp, stat etc.

More details about the fops are present at:
https://review.gluster.org/#/c/13395/3/design/DHT2/DHT2_Icreate_Namelink_Notes.md

This backport of three patches from experimental branch.
1- https://review.gluster.org/#/c/18085/
2- https://review.gluster.org/#/c/18086/
3- https://review.gluster.org/#/c/18094/

Updates gluster/glusterfs#243
Change-Id: I1bd3d5a441a3cfab1acfeb52f15c6c867d362592
Signed-off-by: Susant Palai &lt;spalai@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>protocol/client: Update xlator options table</title>
<updated>2017-11-28T07:37:53+00:00</updated>
<author>
<name>Kaushal M</name>
<email>kaushal@redhat.com</email>
</author>
<published>2017-10-10T10:25:38+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=eba88aed7d2813bfccd1455d4148c4f25d9d0e48'/>
<id>eba88aed7d2813bfccd1455d4148c4f25d9d0e48</id>
<content type='text'>
Updates #302

Change-Id: Ia78e5d8f7b9ee6410965296808ad316c3cfb1d61
Signed-off-by: Amar Tumballi &lt;amarts@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Updates #302

Change-Id: Ia78e5d8f7b9ee6410965296808ad316c3cfb1d61
Signed-off-by: Amar Tumballi &lt;amarts@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Coverity Issue: PW.INCLUDE_RECURSION in several files</title>
<updated>2017-11-09T13:21:11+00:00</updated>
<author>
<name>Girjesh Rajoria</name>
<email>grajoria@redhat.com</email>
</author>
<published>2017-11-02T21:12:23+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=0821a57bd2e7518d1c8df2d4403a2dfbb8ee5b6b'/>
<id>0821a57bd2e7518d1c8df2d4403a2dfbb8ee5b6b</id>
<content type='text'>
Coverity ID: 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417,
418, 419, 423, 424, 425, 426, 427, 428, 429, 436, 437, 438, 439,
440, 441, 442, 443

Issue: Event include_recursion

Removed redundant, recursive includes from the files.

Change-Id: I920776b1fa089a2d4917ca722d0075a9239911a7
BUG: 789278
Signed-off-by: Girjesh Rajoria &lt;grajoria@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Coverity ID: 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417,
418, 419, 423, 424, 425, 426, 427, 428, 429, 436, 437, 438, 439,
440, 441, 442, 443

Issue: Event include_recursion

Removed redundant, recursive includes from the files.

Change-Id: I920776b1fa089a2d4917ca722d0075a9239911a7
BUG: 789278
Signed-off-by: Girjesh Rajoria &lt;grajoria@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Halo Replication feature for AFR translator</title>
<updated>2017-05-02T10:23:53+00:00</updated>
<author>
<name>Kevin Vigor</name>
<email>kvigor@fb.com</email>
</author>
<published>2017-03-21T15:23:25+00:00</published>
<link rel='alternate' type='text/html' href='http://dev.gluster.org/cgit/glusterfs.git/commit/?id=07cc8679cdf3b29680f4f105d0222da168d8bfc1'/>
<id>07cc8679cdf3b29680f4f105d0222da168d8bfc1</id>
<content type='text'>
Summary:
Halo Geo-replication is a feature which allows Gluster or NFS clients to write
locally to their region (as defined by a latency "halo" or threshold if you
like), and have their writes asynchronously propagate from their origin to the
rest of the cluster.  Clients can also write synchronously to the cluster
simply by specifying a halo-latency which is very large (e.g. 10seconds) which
will include all bricks.

In other words, it allows clients to decide at mount time if they desire
synchronous or asynchronous IO into a cluster and the cluster can support both
of these modes to any number of clients simultaneously.

There are a few new volume options due to this feature:
  halo-shd-latency:  The threshold below which self-heal daemons will
  consider children (bricks) connected.

  halo-nfsd-latency: The threshold below which NFS daemons will consider
  children (bricks) connected.

  halo-latency: The threshold below which all other clients will
  consider children (bricks) connected.

  halo-min-replicas: The minimum number of replicas which are to
  be enforced regardless of latency specified in the above 3 options.
  If the number of children falls below this threshold the next
  best (chosen by latency) shall be swapped in.

New FUSE mount options:
  halo-latency &amp; halo-min-replicas: As descripted above.

This feature combined with multi-threaded SHD support (D1271745) results in
some pretty cool geo-replication possibilities.

Operational Notes:
- Global consistency is gaurenteed for synchronous clients, this is provided by
  the existing entry-locking mechanism.
- Asynchronous clients on the other hand and merely consistent to their region.
  Writes &amp; deletes will be protected via entry-locks as usual preventing
  concurrent writes into files which are undergoing replication.  Read operations
  on the other hand should never block.
- Writes are allowed from _any_ region and propagated from the origin to all
  other regions.  The take away from this is care should be taken to ensure
  multiple writers do not write the same files resulting in a gfid split-brain
  which will require resolution via split-brain policies (majority, mtime &amp;
  size).  Recommended method for preventing this is using the nfs-auth feature to
  define which region for each share has RW permissions, tiers not in the origin
  region should have RO perms.

TODO:
- Synchronous clients (including the SHD) should choose clients from their own
  region as preferred sources for reads.  Most of the plumbing is in place for
  this via the child_latency array.
- Better GFID split brain handling &amp; better dent type split brain handling
  (i.e. create a trash can and move the offending files into it).
- Tagging in addition to latency as a means of defining which children you wish
  to synchronously write to

Test Plan:
- The usual suspects, clang, gcc w/ address sanitizer &amp; valgrind
- Prove tests

Reviewers: jackl, dph, cjh, meyering

Reviewed By: meyering

Subscribers: ethanr

Differential Revision: https://phabricator.fb.com/D1272053

Tasks: 4117827

Change-Id: I694a9ab429722da538da171ec528406e77b5e6d1
BUG: 1428061
Signed-off-by: Kevin Vigor &lt;kvigor@fb.com&gt;
Reviewed-on: http://review.gluster.org/16099
Reviewed-on: https://review.gluster.org/16177
Tested-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
Smoke: Gluster Build System &lt;jenkins@build.gluster.org&gt;
NetBSD-regression: NetBSD Build System &lt;jenkins@build.gluster.org&gt;
CentOS-regression: Gluster Build System &lt;jenkins@build.gluster.org&gt;
Reviewed-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Summary:
Halo Geo-replication is a feature which allows Gluster or NFS clients to write
locally to their region (as defined by a latency "halo" or threshold if you
like), and have their writes asynchronously propagate from their origin to the
rest of the cluster.  Clients can also write synchronously to the cluster
simply by specifying a halo-latency which is very large (e.g. 10seconds) which
will include all bricks.

In other words, it allows clients to decide at mount time if they desire
synchronous or asynchronous IO into a cluster and the cluster can support both
of these modes to any number of clients simultaneously.

There are a few new volume options due to this feature:
  halo-shd-latency:  The threshold below which self-heal daemons will
  consider children (bricks) connected.

  halo-nfsd-latency: The threshold below which NFS daemons will consider
  children (bricks) connected.

  halo-latency: The threshold below which all other clients will
  consider children (bricks) connected.

  halo-min-replicas: The minimum number of replicas which are to
  be enforced regardless of latency specified in the above 3 options.
  If the number of children falls below this threshold the next
  best (chosen by latency) shall be swapped in.

New FUSE mount options:
  halo-latency &amp; halo-min-replicas: As descripted above.

This feature combined with multi-threaded SHD support (D1271745) results in
some pretty cool geo-replication possibilities.

Operational Notes:
- Global consistency is gaurenteed for synchronous clients, this is provided by
  the existing entry-locking mechanism.
- Asynchronous clients on the other hand and merely consistent to their region.
  Writes &amp; deletes will be protected via entry-locks as usual preventing
  concurrent writes into files which are undergoing replication.  Read operations
  on the other hand should never block.
- Writes are allowed from _any_ region and propagated from the origin to all
  other regions.  The take away from this is care should be taken to ensure
  multiple writers do not write the same files resulting in a gfid split-brain
  which will require resolution via split-brain policies (majority, mtime &amp;
  size).  Recommended method for preventing this is using the nfs-auth feature to
  define which region for each share has RW permissions, tiers not in the origin
  region should have RO perms.

TODO:
- Synchronous clients (including the SHD) should choose clients from their own
  region as preferred sources for reads.  Most of the plumbing is in place for
  this via the child_latency array.
- Better GFID split brain handling &amp; better dent type split brain handling
  (i.e. create a trash can and move the offending files into it).
- Tagging in addition to latency as a means of defining which children you wish
  to synchronously write to

Test Plan:
- The usual suspects, clang, gcc w/ address sanitizer &amp; valgrind
- Prove tests

Reviewers: jackl, dph, cjh, meyering

Reviewed By: meyering

Subscribers: ethanr

Differential Revision: https://phabricator.fb.com/D1272053

Tasks: 4117827

Change-Id: I694a9ab429722da538da171ec528406e77b5e6d1
BUG: 1428061
Signed-off-by: Kevin Vigor &lt;kvigor@fb.com&gt;
Reviewed-on: http://review.gluster.org/16099
Reviewed-on: https://review.gluster.org/16177
Tested-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
Smoke: Gluster Build System &lt;jenkins@build.gluster.org&gt;
NetBSD-regression: NetBSD Build System &lt;jenkins@build.gluster.org&gt;
CentOS-regression: Gluster Build System &lt;jenkins@build.gluster.org&gt;
Reviewed-by: Pranith Kumar Karampuri &lt;pkarampu@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rpc/clnt: remove locks while notifying CONNECT/DISCONNECT</title>
<updated>2017-03-01T14:35:48+00:00</updated>
<author>
<name>Raghavendra G</name>
<email>rgowdapp@redhat.com</email>
</author>
<published>2017-02-28T07:43:59+00:00</published>
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<id>773f32caf190af4ee48818279b6e6d3c9f2ecc79</id>
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Locking during notify was introduced as part of commit
aa22f24f5db7659387704998ae01520708869873 [1]. The fix was introduced
to fix out-of-order CONNECT/DISCONNECT events from rpc-clnt to parent
xlators [2]. However as part of handling DISCONNECT protocol/client
does unwind saved frames (with failure) waiting for responses. This
saved_frames_unwind can be a costly operation and hence ideally
shouldn't be included in the critical section of notifylock, as it
unnecessarily delays the reconnection to same brick. Also, its not a
good practise to pass control to other xlators holding a lock as it
can lead to deadlocks. So, this patch removes locking in rpc-clnt
while notifying parent xlators.

To fix [2], two changes are present in this patch:

* notify DISCONNECT before cleaning up rpc connection (same as commit
  a6b63e11b7758cf1bfcb6798, patch [3]).
* protocol/client uses rpc_clnt_cleanup_and_start, which cleans up rpc
  connection and does a start while handling a DISCONNECT event from
  rpc. Note that patch [3] was reverted as rpc_clnt_start called in
  quick_reconnect path of protocol/client didn't invoke connect on
  transport as the connection was not cleaned up _yet_ (as cleanup was
  moved post notification in rpc-clnt). This resulted in clients never
  attempting connect to bricks.

Note that one of the neater ways to fix [2] (without using locks) is
to introduce generation numbers to map CONNECT and DISCONNECTS across
epochs and ignore DISCONNECT events if they don't belong to current
epoch. However, this approach is a bit complex to implement and
requires time. So, current patch is a hacky stop-gap fix till we come
up with a more cleaner solution.

[1] http://review.gluster.org/15916
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1386626
[3] http://review.gluster.org/15681

Change-Id: I62daeee8bb1430004e28558f6eb133efd4ccf418
Signed-off-by: Raghavendra G &lt;rgowdapp@redhat.com&gt;
BUG: 1427012
Reviewed-on: https://review.gluster.org/16784
Smoke: Gluster Build System &lt;jenkins@build.gluster.org&gt;
Reviewed-by: Milind Changire &lt;mchangir@redhat.com&gt;
NetBSD-regression: NetBSD Build System &lt;jenkins@build.gluster.org&gt;
CentOS-regression: Gluster Build System &lt;jenkins@build.gluster.org&gt;
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<pre>
Locking during notify was introduced as part of commit
aa22f24f5db7659387704998ae01520708869873 [1]. The fix was introduced
to fix out-of-order CONNECT/DISCONNECT events from rpc-clnt to parent
xlators [2]. However as part of handling DISCONNECT protocol/client
does unwind saved frames (with failure) waiting for responses. This
saved_frames_unwind can be a costly operation and hence ideally
shouldn't be included in the critical section of notifylock, as it
unnecessarily delays the reconnection to same brick. Also, its not a
good practise to pass control to other xlators holding a lock as it
can lead to deadlocks. So, this patch removes locking in rpc-clnt
while notifying parent xlators.

To fix [2], two changes are present in this patch:

* notify DISCONNECT before cleaning up rpc connection (same as commit
  a6b63e11b7758cf1bfcb6798, patch [3]).
* protocol/client uses rpc_clnt_cleanup_and_start, which cleans up rpc
  connection and does a start while handling a DISCONNECT event from
  rpc. Note that patch [3] was reverted as rpc_clnt_start called in
  quick_reconnect path of protocol/client didn't invoke connect on
  transport as the connection was not cleaned up _yet_ (as cleanup was
  moved post notification in rpc-clnt). This resulted in clients never
  attempting connect to bricks.

Note that one of the neater ways to fix [2] (without using locks) is
to introduce generation numbers to map CONNECT and DISCONNECTS across
epochs and ignore DISCONNECT events if they don't belong to current
epoch. However, this approach is a bit complex to implement and
requires time. So, current patch is a hacky stop-gap fix till we come
up with a more cleaner solution.

[1] http://review.gluster.org/15916
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1386626
[3] http://review.gluster.org/15681

Change-Id: I62daeee8bb1430004e28558f6eb133efd4ccf418
Signed-off-by: Raghavendra G &lt;rgowdapp@redhat.com&gt;
BUG: 1427012
Reviewed-on: https://review.gluster.org/16784
Smoke: Gluster Build System &lt;jenkins@build.gluster.org&gt;
Reviewed-by: Milind Changire &lt;mchangir@redhat.com&gt;
NetBSD-regression: NetBSD Build System &lt;jenkins@build.gluster.org&gt;
CentOS-regression: Gluster Build System &lt;jenkins@build.gluster.org&gt;
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