features/quota : Introducing inode quota

==========================================================================
                             Inode quota
==========================================================================
= Currently, the only way to retrieve the number of files/objects in a   =
= directory or volume is to do a crawl of the entire directory/volume.   =
= This is expensive and is not scalable.                                 =
=                                                                        =
= The proposed mechanism will provide an easier alternative to determine =
= the count of files/objects in a directory or volume.                   =
=                                                                        =
= The new mechanism proposes to store count of objects/files as part of  =
= an extended attribute of a directory. Each directory's extended        =
= attribute value will indicate the number of files/objects present      =
= in a tree with the directory being considered as the root of the tree. =
=                                                                        =
= The count value can be accessed by performing a getxattr().            =
= Cluster translators like afr, dht and stripe will perform aggregation  =
= of count values from various bricks when getxattr() happens on the key =
= associated with file/object count.                                     =

A new interface is introduced:
------------------------------
        limit-objects  : limit the number of inodes at directory level
        list-objects   : list the directories where the limit is set
        remove-objects : remove the limit from the directory

==========================================================================

CLI COMMAND:
gluster volume quota <volname> limit-objects <path> <number> [<percent>]

* <number> is a hard-limit for number of objects limitation for path "<path>"
  If hard-limit is exceeded, creation of file/directory is no longer
permitted.

* <percent> is a soft-limit for number of objects creation for path "<path>"
  If soft-limit is exceeded, a warning is issued for each creation.

CLI COMMAND:
gluster volume quota <volname> remove-objects [path]

==========================================================================

CLI COMMAND:
gluster volume quota <volname> list-objects [path] ...

Sample output:
------------------
  Path                   Hard-limit Soft-limit   Used  Available
Soft-limit exceeded?
Hard-limit exceeded?
  ------------------------------------------------------------------------
--------------------------------------
  /dir                      10       80%          10       0
Yes
        Yes

==========================================================================

[root@snapshot-28 dir]# ls
a  b  file11  file12  file13  file14  file15  file16  file17
[root@snapshot-28 dir]# touch a1
touch: cannot touch `a1': Disk quota exceeded
* Nine files are created in directory "dir" and directory is included in
* the
count too. Hence the limit "10" is reached and further file creation
fails

==========================================================================

Note: We have also done some re-factoring in cli for volume name
validation. New function cli_validate_volname is created

==========================================================================

Change-Id: I1823497de4f790a2a20ebb1770293472ea33ee2b
BUG: 1190108
Signed-off-by: Sachin Pandit <spandit@redhat.com>
Signed-off-by: vmallika <vmallika@redhat.com>
Reviewed-on: http://review.gluster.org/9769
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/libglusterfs/src/quota-common-utils.c b/libglusterfs/src/quota-common-utils.c
new file mode 100644
index 00000000000..8cc09e8fff7
--- /dev/null
+++ b/libglusterfs/src/quota-common-utils.c
@@ -0,0 +1,99 @@
+/*
+   Copyright (c) 2015 Red Hat, Inc. <http://www.redhat.com>
+   This file is part of GlusterFS.
+
+   This file is licensed to you under your choice of the GNU Lesser
+   General Public License, version 3 or any later version (LGPLv3 or
+   later), or the GNU General Public License, version 2 (GPLv2), in all
+   cases as published by the Free Software Foundation.
+*/
+
+
+#include "dict.h"
+#include "logging.h"
+#include "byte-order.h"
+#include "quota-common-utils.h"
+
+int32_t
+quota_dict_get_meta (dict_t *dict, char *key, quota_meta_t *meta)
+{
+        int32_t        ret      = -1;
+        data_t        *data     = NULL;
+        quota_meta_t  *value    = NULL;
+        int64_t       *size     = NULL;
+
+        if (!dict || !key || !meta)
+                goto out;
+
+        data = dict_get (dict, key);
+        if (!data || !data->data)
+                goto out;
+
+        if (data->len > sizeof (int64_t)) {
+                value = (quota_meta_t *) data->data;
+                meta->size = ntoh64 (value->size);
+                meta->file_count = ntoh64 (value->file_count);
+                if (data->len > (sizeof (int64_t)) * 2)
+                        meta->dir_count  = ntoh64 (value->dir_count);
+                else
+                        meta->dir_count = 0;
+        } else {
+                size = (int64_t *) data->data;
+                meta->size = ntoh64 (*size);
+                meta->file_count = 0;
+                meta->dir_count = 0;
+                /* This can happen during software upgrade.
+                 * Older version of glusterfs will not have inode count.
+                 * Return failure, this will be healed as part of lookup
+                 */
+                gf_log_callingfn ("quota", GF_LOG_DEBUG, "Object quota xattrs "
+                                  "missing: len = %d", data->len);
+                ret = -2;
+                goto out;
+        }
+
+        ret = 0;
+out:
+
+        return ret;
+}
+
+int32_t
+quota_dict_set_meta (dict_t *dict, char *key, const quota_meta_t *meta,
+                     ia_type_t ia_type)
+{
+        int32_t         ret      = -1;
+        quota_meta_t   *value    = NULL;
+
+        value = GF_CALLOC (1, sizeof (quota_meta_t), gf_common_quota_meta_t);
+        if (value == NULL) {
+                gf_log_callingfn ("quota", GF_LOG_ERROR,
+                                  "Memory allocation failed");
+                goto out;
+        }
+
+        value->size = hton64 (meta->size);
+        value->file_count = hton64 (meta->file_count);
+        value->dir_count = hton64 (meta->dir_count);
+
+        if (ia_type == IA_IFDIR) {
+                ret = dict_set_bin (dict, key, value, sizeof (*value));
+        } else {
+                /* For a file we don't need to store dir_count in the
+                 * quota size xattr, so we set the len of the data in the dict
+                 * as 128bits, so when the posix xattrop reads the dict, it only
+                 * performs operations on size and file_count
+                 */
+                ret = dict_set_bin (dict, key, value,
+                                    sizeof (*value) - sizeof (int64_t));
+        }
+
+        if (ret < 0) {
+                gf_log_callingfn ("quota", GF_LOG_ERROR, "dict set failed");
+                GF_FREE (value);
+        }
+
+out:
+        return ret;
+}
+