From,
$ targetcli /backstores/user:glfs/block get attribute
ATTRIBUTE CONFIG GROUP
======================
hw_block_size=512 [ro]
----------------------

Hence making the min acceptable size to be 1 sector/block i.e. 512 bytes

This patch also, explicitly mention in docs about bytes as default size units.

Change-Id: Iec8797082d02cc9ad51fc17e11f2ba3073aaeda0
Fixes: #35
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

blockResponse *
block_delete_1(blockDelete *argp, CLIENT *clnt)
{
        static blockResponse clnt_res; <<<<<<-------- Same memory is used by everyone

        memset((char *)&clnt_res, 0, sizeof(clnt_res)); <<<<<---- Here memset is happening
        if (clnt_call (clnt, BLOCK_DELETE,
                (xdrproc_t) xdr_blockDelete, (caddr_t) argp,
                (xdrproc_t) xdr_blockResponse, (caddr_t) &clnt_res,
                TIMEOUT) != RPC_SUCCESS) {
                return (NULL);
        }
        return (&clnt_res); <<<<<---- ptr to this memory is returned.
}

So while Thread-1 is returned "return (&clnt_res);" another thread could be
doing "memset((char *)&clnt_res, 0, sizeof(clnt_res));"

This seem to be a day-1 gluster-blockd bug from the looks of it.

Change-Id: I3fc76d7814c4fe5b286577586ec44d752dcc73f0
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

Currently the default logdir is DATADIR /log/gluster-block/

This patch will provide a way to change this default logdir via Env variable
$ export GB_LOGDIR=/var/log/gluster-block-new-path/

Note: make sure to restart the processes (cli & daemon) after you set GB_LOGDIR

Change-Id: Id142e4a4dfe7b6ebc9cf8296b8ceb8bff37691b8
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

$ gluster-block help
gluster-block (0.2.1)
usage:
  gluster-block <command> <volname[/blockname]> [<args>] [--json*]

commands:
[...]
  delete  <volname/blockname> [force]
        delete block device.
[...]

Change-Id: I64ac01ec148e2e1d4d0ba0d4c5560df9334d58f5
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

$ gluster-block create
Inadequate arguments for create:
gluster-block create <volname/blockname> [ha <count>] [auth<enable|disable>] \
    [prealloc <full|no>] <HOST1[,HOST2,...]> <size> [--json*]

Change-Id: Ib089598fd9b386bd3475dd421b41c45ebb01c9d2
Fixes: #33
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

Change-Id: I06f20a355453d81955d4308ecad68358fa1f99cc
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

currently we allocate sparse files for block backends in the gluster
volume, with 'prealloc = full' option introduced by this patch we should
be able to fully preallocate the backend block file.

Change-Id: Ibf32df5f978f732a3fd248693170463da6d08268
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

Also s/BLOCK CONFIG NODE(S)/EXPORTED NODE(S)/ in the info output

$ gluster-block info sample/block
NAME: block
VOLUME: sample
GBID: 6bd70984-be2c-43ac-9e9d-bad04010e42f
SIZE: 1.0 GiB
HA: 1
PASSWORD:
EXPORTED NODE(S): 192.168.0.105

Change-Id: I473b854b939c96b99be8e0b172ac6957b8bc6006
Fixes: #23
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

$ gluster-blockd --help
gluster-blockd (0.2)
usage:
  gluster-blockd [--glfs-lru-count <count>]

commands:
  --glfs-lru-count <count>
        glfs objects cache capacity [max: 512] (default: 5)
  --help
        show this message and exit.
  --version
        show version info and exit.

Change-Id: I00a9277690a1c5ace51e223e9e4ed9ce61ae2428
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

Also refactored the code around to reduce number of allocations.

Change-Id: If5431f1504b6716ac4baec3a859189f6f21c80a4
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>