glusterfs.git/xlators/cluster/dht/src/dht-layout.c, branch v4.0.0alpha

glusterfs: Use gcc builtin ATOMIC operator to increase/decreate refcount.

2017-12-12T09:05:56+00:00

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 < numOuterLoops; j++) {
            __atomic_add_fetch (&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 < 2 ) {
     printf(" Please provide 2 args Num of threads && 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 (&glob, &n, __ATOMIC_RELEASE);
    for (j = 0; j < numThreads; j++) {
        s = pthread_create(&thread[j], NULL, threadFunc, NULL);
        if (s != 0) {
            printf ("pthread_create failed so exit\n");
            exit (-1);
        }
    }

    for (j = 0; j < 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 (&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

cluster/dht: populate inode in dentry for single subvolume dht

2017-12-02T11:46:52+00:00

... in readdirp response if dentry points to a directory inode. This
is a special case where the entire layout is stored in one single
subvolume and hence no need for lookup to construct the layout

Change-Id: I44fd951e2393ec9dac2af120469be47081a32185
BUG: 1492625
Signed-off-by: Raghavendra G

cluster/dht: Check if fd is opened on dst subvol

2017-06-28T11:42:21+00:00

If an fd is opened on a file, the file is migrated
and the cached subvol is updated in the inode_ctx
before an fd based fop is sent, the fop is sent to
the dst subvol on which the fd is not opened.
This causes the FOP to fail with EBADF.

Now, every fd based fop will check to see that the fd
has been opened on the dst subvol before winding it down.

Change-Id: Id92ef5eb7a5b5226688e2d2868b15e383f5f240e
BUG: 1465075
Signed-off-by: N Balachandran 
Reviewed-on: https://review.gluster.org/17630
Smoke: Gluster Build System 
Reviewed-by: Raghavendra G 
Reviewed-by: Susant Palai 
CentOS-regression: Gluster Build System

cluster/distribute: detect stale layouts in entry fops

2016-04-22T17:28:54+00:00

dht_mkdir ()
{
      first-hashed-subvol = hashed-subvol for "bname" in in-memory
                            layout of "parent";
      inodelk (SETLKW, parent, "LAYOUT_HEAL_DOMAIN", "can be any
               subvol, but we choose first-hashed-subvol randomly");
      {
begin:
            hashed-subvol = hashed-subvol for "bname" in in-memory
                            layout of "parent";
            hash-range = extract hashe-range from layout of "parent";

            ret = mkdir (parent/bname, hashed-subvol, hash-range);
            if (ret == "hash-value doesn't fall into layout stored on
                       the brick (this error is returned by posix-mkdir)")
            {
                refresh_parent_layout ();
                goto begin;
            }

      }
      inodelk (UNLCK, parent, "LAYOUT_HEAL_DOMAIN",
               "first-hashed-subvol");

      proceed with other parts of dht_mkdir;
}

posix_mkdir (parent/bname, client-hash-range)
{

       disk-hash-range = getxattr (parent, "dht-layout-key");
       if (disk-hash-range != client-hash-range) {
              fail-with-error ("hash-value doesn't fall into layout
                                stored on the brick");
              return 0;
       }

       continue-with-posix-mkdir;
}

Similar changes need to be done for dentry operations like create,
symlink, link, unlink, rmdir, rename. These will be addressed in
subsequent patches. This patch addresses only mkdir codepath.

This change breaks stripe tests, as on some striped subvols dht layout
xattrs are not set for some reason. This results in failure of
mkdir. Since striped volumes are always created with dht, some tests
associated with stripe also fail. So, I am making following tests
changes (since stripe is out of maintainance):
* modify ./tests/basic/rpc-coverage.t to not to use striped volumes
* mark all (2) tests in tests/bugs/stripe/ as bad tests

Change-Id: Idd1ae879f24a48303dc743c1bb4d91f89a629e25
BUG: 1323040
Signed-off-by: Raghavendra G 
Reviewed-on: http://review.gluster.org/13885
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: N Balachandran

dht : updating return value for layout set function

2015-08-13T05:59:56+00:00

Change-Id: I7fd89e00b418391afe0a13c2033919c979cc8bbb
BUG: 789278
Signed-off-by: Sakshi 
Reviewed-on: http://review.gluster.org/10869
Tested-by: NetBSD Build System 
Reviewed-by: N Balachandran 
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra G

dht: Adding log messages to the new logging framework

2015-06-24T05:15:10+00:00

Change-Id: Ib3bb61c5223f409c23c68100f3fe884918d2dc3f
BUG: 1194640
Signed-off-by: arao 
Reviewed-on: http://review.gluster.org/10021
Reviewed-by: N Balachandran 
Reviewed-by: Joseph Fernandes
Tested-by: Joseph Fernandes
Reviewed-by: Dan Lambright 
Reviewed-by: Raghavendra G 
Tested-by: Raghavendra G

build: do not #include "config.h" in each file

2015-05-29T12:43:17+00:00

Instead of including config.h in each file, and have the additional
config.h included from the compiler commandline (-include option).

When a .c file tests for a certain #define, and config.h was not
included, incorrect assumtions were made. With this change, it can not
happen again.

BUG: 1222319
Change-Id: I4f9097b8740b81ecfe8b218d52ca50361f74cb64
Signed-off-by: Niels de Vos 
Reviewed-on: http://review.gluster.org/10808
Tested-by: Gluster Build System 
Tested-by: NetBSD Build System
Reviewed-by: Kaleb KEITHLEY 
Reviewed-by: Pranith Kumar Karampuri

dht: make lookup-unhashed=auto do something actually useful

2015-05-10T13:17:22+00:00

The key concept here is to determine whether a directory is "clean" by
comparing its last-known-good topology to the current one for the
volume.  These are stored as "commit hashes" on the directory and the
volume root respectively.  The volume's commit hash changes whenever a
brick is added or removed, and a fix-layout is done.  A directory's
commit hash changes only when a full rebalance (not just fix-layout)
is done on it.  If all bricks are present and have a directory
commit hash that matches the volume commit hash, then we can assume
that every file is in its "proper" place. Therefore, if we look for
a file in that proper place and don't find it, we can assume it's not
on any other subvolume and *safely* skip the global (broadcast to all)
lookup.

Change-Id: Id6ce4593ba1f7daffa74cfab591cb45960629ae3
BUG: 1219637
Signed-off-by: Jeff Darcy 
Signed-off-by: Shyam 
Reviewed-on: http://review.gluster.org/7702
Tested-by: Gluster Build System 
Tested-by: NetBSD Build System
Reviewed-by: Vijay Bellur

dht: Fixing dereference after null check

2015-05-08T08:22:35+00:00

CID: 1223229
The 'loc' ptr is not checked before
dereferencing, which is handled.

Change-Id: Icf668150bde190e6f1b9f58a038099338516efe8
BUG: 789278
Signed-off-by: arao 
Reviewed-on: http://review.gluster.org/9666
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra G 
Tested-by: Raghavendra G

dht : coverity fixes

2015-04-07T10:52:05+00:00

CID : 1124352,1124365 (unchecked return value),
      1124377 ( logically dead code),
      1124511 (null dereference)

Change-Id: I61e029a078559cfe15d36bf0aa53418f6214e5cb
BUG: 789278
Signed-off-by: Manikandan Selvaganesh 
Reviewed-on: http://review.gluster.org/9622
Tested-by: Gluster Build System 
Reviewed-by: Shyamsundar Ranganathan 
Reviewed-by: Kaleb KEITHLEY 
Reviewed-by: N Balachandran 
Reviewed-by: Vijay Bellur