improve quotas not enabled behaviour #1869

Uses the existing -1/-1 default for pqgoups to represent
an unset state for the share.pqgroup and adds an active
return to this value whenever quotas are deemed to be
disabled. Pqgroup setup is moved from the bootstrap
process into the import_shares / shares refresh section.
This allows for live setting / resetting of pqgroups via
the regular share re-fresh process. Pool.quotas_enabled
and share.pqgroup_exist properties are added and all used
low level quota actions are adjusted to catch, log, and
ignore a quota disabled state.
Additionally active pqgroup assignment is added to share
resize and share refresh procedures which aid in returning
to existence the expected native 2015/n pqgroups and their
relationship to the auto generated 0/n qgroups as whenever
quotas are disabled all this info (var the 0/n) is lost.
UI elements are added in pool and share focused pages to
indicate a live status for the associated pool quotas
enabled status.

src/rockstor/fs/btrfs.py

@@ -26,6 +26,7 @@
 from system.exceptions import (CommandException)
 from pool_scrub import PoolScrub
 from django_ztask.decorators import task
+from django.conf import settings
 import logging
 
 """
@@ -41,7 +42,8 @@
 DEFAULT_MNT_DIR = '/mnt2/'
 RMDIR = '/bin/rmdir'
 QID = '2015'
-
+# The following model/db default setting is also used when quotas are disabled.
+PQGROUP_DEFAULT = settings.MODEL_DEFS['pqgroup']
 
 def add_pool(pool, disks):
     """
@@ -678,13 +680,71 @@ def disable_quota(pool_name):
     return switch_quota(pool_name, flag='disable')
 
 
+def are_quotas_enabled(mnt_pt):
+    """
+    Simple wrapper around 'btrfs qgroup show -f --raw mnt_pt' intended
+    as a fast determiner of True / False status of quotas enabled
+    :param mnt_pt: Mount point of btrfs filesystem
+    :return: True on rc = 0 False otherwise.
+    """
+    o, e, rc = run_command([BTRFS, 'qgroup', 'show', '-f', '--raw', mnt_pt])
+    if rc == 0:
+        return True
+    return False
+
+
+def qgroup_exists(mnt_pt, qgroup):
+    """
+    Simple wrapper around 'btrfs qgroup show --raw mnt_pt' intended to
+    establish if a specific qgroup exists on a btrfs filesystem.
+    :param mnt_pt: btrfs filesystem mount point, usually the pool.
+    :param qgroup: qgroup of the form 2015/n (intended for use with pqgroup)
+    :return: True is given qgroup exists in command output, False otherwise.
+    """
+    o, e, rc = run_command([BTRFS, 'qgroup', 'show', '--raw', mnt_pt])
+    # example output:
+    # 'qgroupid         rfer         excl '
+    # '-------         ----         ---- '
+    # '0/5             16384        16384 '
+    # ...
+    # '2015/12             0            0 '
+    if rc == 0 and len(o) > 2:
+        # index from 2 to miss header lines and -1 to skip end blank line = []
+        qgroup_list = [line.split()[0] for line in o[2:-1]]
+        # eg from rockstor_rockstor pool we get:
+        # qgroup_list=['0/5', '0/257', '0/258', '0/260', '2015/1', '2015/2']
+        if qgroup in qgroup_list:
+            return True
+    return False
+
+
 def qgroup_id(pool, share_name):
     sid = share_id(pool, share_name)
     return '0/' + sid
 
 
 def qgroup_max(mnt_pt):
-    o, e, rc = run_command([BTRFS, 'qgroup', 'show', mnt_pt], log=True)
+    """
+    Parses the output of "btrfs qgroup show mnt_pt" to find the highest qgroup
+    matching QID/* if non is found then 0 will be returned.
+    Quotas not enabled is flagged by a -1 return value.
+    :param mnt_pt: A given btrfs mount point.
+    :return: -1 if quotas not enabled, else highest 2015/* qgroup found or 0
+    """
+    try:
+        o, e, rc = run_command([BTRFS, 'qgroup', 'show', mnt_pt], log=True)
+    except CommandException as e:
+        # disabled quotas will result in o = [''], rc = 1 and e[0] =
+        emsg = "ERROR: can't list qgroups: quotas not enabled"
+        # this is non fatal so we catch this specific error and info log it.
+        if e.rc == 1 and e.err[0] == emsg:
+            logger.info('Mount Point: {} has Quotas disabled, skipping qgroup '
+                        'show.'.format(mnt_pt))
+            # and return our default res
+            return -1
+        # otherwise we raise an exception as normal.
+        raise
+    # if no exception was raised find the max 2015/qgroup
     res = 0
     for l in o:
         if (re.match('%s/' % QID, l) is not None):
@@ -694,10 +754,33 @@ def qgroup_max(mnt_pt):
     return res
 
 
-def qgroup_create(pool):
+def qgroup_create(pool, qgroup='-1/-1'):
+    """
+    When passed only a pool an attempt will be made to ascertain if quotas is
+    enabled, if not '-1/-1' is returned as a flag to indicate this state.
+    If quotas are not enabled then the highest available quota of the form
+    2015/n is selected and created, if possible.
+    If passed both a pool and a specific qgroup an attempt is made, given the
+    same behaviour as above, to create this specific group: this scenario is
+    primarily used to re-establish prior existing qgroups post quota disable,
+    share manipulation, quota enable cycling.
+    :param pool: A pool object.
+    :param qgroup: native qgroup of the form 2015/n
+    :return: -1/-1 on quotas disabled, otherwise it will return the native
+    quota whose creation was attempt.
+    """
     # mount pool
     mnt_pt = mount_root(pool)
-    qid = ('%s/%d' % (QID, qgroup_max(mnt_pt) + 1))
+    max_native_qgroup = qgroup_max(mnt_pt)
+    if max_native_qgroup == -1:
+        # We have received a quotas disabled flag so will be unable to create
+        # a new quota group. So return our db default which can in turn flag
+        # an auto updated of pqgroup upon next refresh-share-state.
+        return PQGROUP_DEFAULT
+    if qgroup != PQGROUP_DEFAULT:
+        qid = qgroup
+    else:
+        qid = ('%s/%d' % (QID, max_native_qgroup + 1))
     try:
         out, err, rc = run_command([BTRFS, 'qgroup', 'create', qid, mnt_pt],
                                    log=True)
@@ -715,7 +798,18 @@ def qgroup_create(pool):
 
 
 def qgroup_destroy(qid, mnt_pt):
-    o, e, rc = run_command([BTRFS, 'qgroup', 'show', mnt_pt])
+    cmd = [BTRFS, 'qgroup', 'show', mnt_pt]
+    try:
+        o, e, rc = run_command(cmd, log=True)
+    except CommandException as e:
+        # we may have quotas disabled so catch and deal.
+        emsg = "ERROR: can't list qgroups: quotas not enabled"
+        if e.rc == 1 and e.err[0] == emsg:
+            # we have quotas disabled so can't destroy any anyway so skip
+            # and deal by returning False so our caller moves on.
+            return False
+        # otherwise we raise an exception as normal
+        raise e
     for l in o:
         if (re.match(qid, l) is not None and l.split()[0] == qid):
             return run_command([BTRFS, 'qgroup', 'destroy', qid, mnt_pt],
@@ -726,7 +820,19 @@ def qgroup_destroy(qid, mnt_pt):
 def qgroup_is_assigned(qid, pqid, mnt_pt):
     # Returns true if the given qgroup qid is already assigned to pqid for the
     # path(mnt_pt)
-    o, e, rc = run_command([BTRFS, 'qgroup', 'show', '-pc', mnt_pt])
+    cmd = [BTRFS, 'qgroup', 'show', '-pc', mnt_pt]
+    try:
+        o, e, rc = run_command(cmd, log=True)
+    except CommandException as e:
+        # we may have quotas disabled so catch and deal.
+        emsg = "ERROR: can't list qgroups: quotas not enabled"
+        if e.rc == 1 and e.err[0] == emsg:
+            # No deed to scan output as nothing to see with quotas disabled.
+            # And since no quota capability can be enacted we return True
+            # to avoid our caller trying any further with quotas.
+            return True
+        # otherwise we raise an exception as normal
+        raise e
     for l in o:
         fields = l.split()
         if (len(fields) > 3 and
@@ -736,15 +842,34 @@ def qgroup_is_assigned(qid, pqid, mnt_pt):
     return False
 
 
+def share_pqgroup_assign(pqgroup, share):
+    """
+    Convenience wrapper to qgroup_assign() for use with a share object where
+    we wish to assign / reassign it's current db held qgroup to a passed
+    pqgroup.
+    :param pqgroup: pqgroup to use as parent.
+    :param share: share object
+    :return: qgroup_assign() result.
+    """
+    mnt_pt = '{}/{}'.format(settings.MNT_PT, share.pool.name)
+    return qgroup_assign(share.qgroup, pqgroup, mnt_pt)
+
+
 def qgroup_assign(qid, pqid, mnt_pt):
+    """
+    Wrapper for 'BTRFS, qgroup, assign, qid, pqid, mnt_pt'
+    :param qid: qgroup to assign as child of pqgroup
+    :param pqid: pqgroup to use as parent
+    :param mnt_pt: btrfs filesystem mountpoint (usually the associated pool)
+    """
     if (qgroup_is_assigned(qid, pqid, mnt_pt)):
         return True
 
     # since btrfs-progs 4.2, qgroup assign succeeds but throws a warning:
     # "WARNING: # quotas may be inconsistent, rescan needed" and returns with
     # exit code 1.
     try:
-        run_command([BTRFS, 'qgroup', 'assign', qid, pqid, mnt_pt])
+        run_command([BTRFS, 'qgroup', 'assign', qid, pqid, mnt_pt], log=True)
     except CommandException as e:
         wmsg = 'WARNING: quotas may be inconsistent, rescan needed'
         if (e.rc == 1 and e.err[0] == wmsg):
@@ -766,14 +891,21 @@ def qgroup_assign(qid, pqid, mnt_pt):
 
 
 def update_quota(pool, qgroup, size_bytes):
+    # TODO: consider changing qgroup to pqgroup if we are only used this way.
     root_pool_mnt = mount_root(pool)
     # Until btrfs adds better support for qgroup limits. We'll not set limits.
     # It looks like we'll see the fixes in 4.2 and final ones by 4.3.
+    # Update: Further quota improvements look to be landing in 4.15.
     # cmd = [BTRFS, 'qgroup', 'limit', str(size_bytes), qgroup, root_pool_mnt]
     cmd = [BTRFS, 'qgroup', 'limit', 'none', qgroup, root_pool_mnt]
     # Set defaults in case our run_command fails to assign them.
     out = err = ['']
     rc = 0
+    if qgroup == '-1/-1':
+        # We have a 'quotas disabled' qgroup value flag, log and return blank.
+        logger.info('Pool: {} ignoring '
+                    'update_quota on {}'.format(pool.name, qgroup))
+        return out, err, rc
     try:
         out, err, rc = run_command(cmd, log=True)
     except CommandException as e:
@@ -785,6 +917,25 @@ def update_quota(pool, qgroup, size_bytes):
             logger.info('Pool: {} is Read-only, skipping qgroup '
                         'limit.'.format(pool.name))
             return out, err, rc
+        # quotas disabled results in o = [''], rc = 1 and e[0] =
+        emsg2 = 'ERROR: unable to limit requested quota group: ' \
+                'Invalid argument'
+        # quotas disabled is not a fatal failure but here we key from what
+        # is a non specific error: 'Invalid argument'.
+        # TODO: improve this clause as currently too broad.
+        # TODO: we could for example use if qgroup_max(mnt) == -1
+        if e.rc == 1 and e.err[0] == emsg2:
+            logger.info('Pool: {} has encountered a qgroup limit issue, '
+                        'skipping qgroup limit. Disabled quotas can cause '
+                        'this error'.format(pool.name))
+            return out, err, rc
+        emsg3 = 'ERROR: unable to limit requested quota group: ' \
+                'No such file or directory'
+        if e.rc == 1 and e.err[0] == emsg3:
+            logger.info('Pool: {} is missing expected '
+                        'qgroup {}'.format(pool.name, qgroup))
+            logger.info('Previously disabled quotas can cause this issue')
+            return out, err, rc
         # raise an exception as usual otherwise
         raise
     return out, err, rc

src/rockstor/storageadmin/models/pool.py

@@ -18,7 +18,8 @@
 
 from django.db import models
 from django.conf import settings
-from fs.btrfs import pool_usage, usage_bound
+from fs.btrfs import pool_usage, usage_bound, \
+    are_quotas_enabled
 from system.osi import mount_status
 
 RETURN_BOOLEAN = True
@@ -74,5 +75,13 @@ def is_mounted(self, *args, **kwargs):
         except:
             return False
 
+    @property
+    def quotas_enabled(self, *args, **kwargs):
+        # Calls are_quotas_enabled for boolean response
+        try:
+            return are_quotas_enabled('%s%s' % (settings.MNT_PT, self.name))
+        except:
+            return False
+
     class Meta:
         app_label = 'storageadmin'

src/rockstor/storageadmin/models/share.py

@@ -21,6 +21,7 @@
 from django.db.models.signals import (post_save, post_delete)
 from django.dispatch import receiver
 
+from fs.btrfs import qgroup_exists
 from storageadmin.models import Pool
 from system.osi import mount_status
 from .netatalk_share import NetatalkShare
@@ -81,6 +82,19 @@ def is_mounted(self, *args, **kwargs):
         except:
             return False
 
+    @property
+    def pqgroup_exist(self, *args, **kwargs):
+        # Returns boolean status of pqgroup existence
+        try:
+            if str(self.pqgroup) == '-1/-1':
+                return False
+            else:
+                return qgroup_exists(
+                    '%s%s' % (settings.MNT_PT, self.pool.name),
+                    '%s' % self.pqgroup)
+        except:
+            return False
+
     class Meta:
         app_label = 'storageadmin'
 

src/rockstor/storageadmin/serializers.py

@@ -51,6 +51,7 @@ class PoolInfoSerializer(serializers.ModelSerializer):
     reclaimable = serializers.IntegerField()
     mount_status = serializers.CharField()
     is_mounted = serializers.BooleanField()
+    quotas_enabled = serializers.BooleanField()
 
     class Meta:
         model = Pool
@@ -145,6 +146,7 @@ class ShareSerializer(serializers.ModelSerializer):
     nfs_exports = NFSExportSerializer(many=True, source='nfsexport_set')
     mount_status = serializers.CharField()
     is_mounted = serializers.BooleanField()
+    pqgroup_exist = serializers.BooleanField()
 
     class Meta:
         model = Share

src/rockstor/storageadmin/static/storageadmin/js/templates/pool/pool_info_module.jst

@@ -30,6 +30,13 @@
   {{else}}
     <span style="color:red">{{model.mount_status}}</span>
   {{/if}}
+  </strong><br/>
+  Quotas: <strong>
+  {{#if model.quotas_enabled}}
+    Enabled
+  {{else}}
+    <span style="color:red">Disabled</span>
+  {{/if}}
   </strong>
 </div> <!-- module-content -->
 

src/rockstor/storageadmin/static/storageadmin/js/templates/pool/pools_table.jst

@@ -5,6 +5,7 @@
       <th>Name</th>
       <th>Size</th>
       <th>Usage</th>
+      <th>Quotas</th>
       <th>Raid</th>
       <th>Active mount options / Status</th>
       <th>Compression</th>
@@ -32,7 +33,12 @@
             <td>{{humanReadableSize 'usage' this.size this.reclaimable this.free}}
                 <strong>({{humanReadableSize 'usagePercent' this.size this.reclaimable this.free}} %)</strong>
             </td>
-
+            <td>{{#if this.quotas_enabled}}
+                    Enabled
+                {{else}}
+                    <strong><span style="color:red">Disabled</span></strong>
+                {{/if}}
+            </td>
             <td>{{this.raid}}
                 {{#unless (isRoot this.role)}}
                       &nbsp;<a href="#pools/{{this.id}}/?cView=resize"><i class="fa fa-pencil-square-o"></i></a>

src/rockstor/storageadmin/static/storageadmin/js/templates/share/share_usage_module.jst

@@ -28,6 +28,13 @@
     (<strong><span style="color:red">{{pool_mount_status}}</span></strong>)
   {{/if}}
   <br>
+  Pool Quotas:&nbsp;
+  {{#if pool_quotas_enabled}}
+    Enabled
+  {{else}}
+    <strong><span style="color:red">Disabled</span></strong>
+  {{/if}}
+  <br>
   Active mount options / Status:
   <strong>
   {{#if share_is_mounted}}

src/rockstor/storageadmin/static/storageadmin/js/templates/share/shares_table.jst

@@ -12,11 +12,11 @@
       <tr>
         <th>Name</th>
         <th>Size</th>
-        <th>Usage <i class="fa fa-info-circle" title="Current share content"></th>
-        <th>Btrfs Usage <i class="fa fa-info-circle" title="Current share content including snapshots"></th>
+        <th>Usage <i class="fa fa-info-circle" title="Share content - uses Quotas" /></th>
+        <th>Btrfs Usage <i class="fa fa-info-circle" title="Share content inc snapshots - uses Quotas" /></th>
         <th>Active mount options / Status</th>
-        <th>Pool (Active mount options / Status)</th>
-        <th>Compression <i class="fa fa-info-circle" title="Inherits pool setting if not specified on share"></th>
+        <th>Pool (Active mount options / Status) Quotas</th>
+        <th>Compression <i class="fa fa-info-circle" title="Inherits pool setting if not specified on share" /></th>
         <th>Actions</th>
       </tr>
     </thead>
@@ -40,6 +40,11 @@
             {{else}}
                 (<strong><span style="color:red">{{this.pool.mount_status}}</span></strong>)
             {{/if}}
+            {{# if this.pool.quotas_enabled}}
+                Enabled
+            {{else}}
+                <strong><span style="color:red">Disabled</span></strong>
+            {{/if}}
         </td>
         <td>
         {{displayCompressionAlgo this.compression_algo this.id}}