cluster/afr : Implementation of command "gluster volume heal vn statistics"

"gluster volume heal volumename statistics" command gives the summary
of the afr crawl done based on the entries present in the xattrop
directory. Whenever afr crawls are attempted, the beginning time of
crawl, end time of crawl, no of files healed, heal-failed count and
number of files in split brain are shown along with the type of the
crawl. If crawl is already in progress then it will give the number
of files healed, heal failed count and number of files in split-brain
from the beginning of the crawl and instead of telling the end time of
the crawl, "CRAWL IN PROGRESS" message will be shown.

Output format:
command: "gluster volume heal volume-name statistics"
Output:
Gathering afr crawl statistics crawl statistics on volume volume-name
has been successful
------------------------------------------------

Crawl statistics for brick no 0
Hostname of brick 192.168.122.248

Starting time of crawl: Wed Jul 10 15:52:38 2013

Ending time of crawl: Wed Jul 10 15:52:38 2013

Type of crawl: INDEX
No. of entries healed: 0
No. of entries in split-brain: 0
No. of heal failed entries: 0

Starting time of crawl: Wed Jul 10 15:52:38 2013

Ending time of crawl: Wed Jul 10 15:52:38 2013

Type of crawl: INDEX
No. of entries healed: 0
No. of entries in split-brain: 0
No. of heal failed entries: 0

------------------------------------------------

Crawl statistics for brick no 1
Hostname of brick 192.168.122.1

Starting time of crawl: Wed Jul 10 15:52:42 2013

Ending time of crawl: Wed Jul 10 15:52:42 2013

Type of crawl: INDEX
No. of entries healed: 0
No. of entries in split-brain: 0
No. of heal failed entries: 0

Starting time of crawl: Wed Jul 10 15:52:42 2013

Ending time of crawl: Wed Jul 10 15:52:42 2013

Type of crawl: INDEX
No. of entries healed: 0
No. of entries in split-brain: 0
No. of heal failed entries: 0

--------------------------------------------------

Change-Id: I10bf9d10b005741db9973fb1352e0dd59ed99aa9
BUG: 949400
Signed-off-by: Venkatesh Somyajulu <vsomyaju@redhat.com>
Reviewed-on: http://review.gluster.org/4790
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>
cluster/afr: [Feature] Command implementation to get heal-count

Currently to know the number of files to be healed, either user
has to go to backend and check the number of entries present in
indices/xattrop directory. But if a volume consists of large
number of bricks, going to each backend and counting the number
of entries is a time-taking task. Otherwise user can give
gluster volume heal vol-name info command but with this
approach if no. of entries are very hugh in the indices/
xattrop directory, it will comsume time.

So as a feature, new command is implemented.

Command 1: gluster volume heal vn statistics heal-count
This command will get the number of entries present in
every brick of a volume. The output displays only entries
count.

Command 2: gluster volume heal vn statistics heal-count
           replica 192.168.122.1:/home/user/brickname

           Here if we are concerned with just one replica.
So providing any one of the brick of a replica will get
the number of entries to be healed for that replica only.

Example:
Replicate volume with replica count 2.

Backend status:
--------------
[root@dhcp-0-17 xattrop]# ls -lia | wc -l
1918

NOTE: Out of 1918, 2 entries are <xattrop-gfid> dummy
entries so actual no. of entries to be healed are
1916.

[root@dhcp-0-17 xattrop]# pwd
/home/user/2ty/.glusterfs/indices/xattrop

Command output:
--------------
Gathering count of entries to be healed on volume volume3 has been successful

Brick 192.168.122.1:/home/user/22iu
Status: Brick is Not connected
Entries count is not available

Brick 192.168.122.1:/home/user/2ty
Number of entries: 1916

Change-Id: I72452f3de50502dc898076ec74d434d9e77fd290
BUG: 1015990
Signed-off-by: Venkatesh Somyajulu <vsomyaju@redhat.com>
Reviewed-on: http://review.gluster.org/6044
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>