glusterfs.git/xlators/features/quota/src/quotad-helpers.c, branch v4.2dev

rpc: Maintain separate xlator pointer in 'rpcsvc_state'

2015-05-04T11:08:26+00:00

The structure 'rpcsvc_state', which maintains rpc server
state had no separate pointer to track the translator.
It was using the mydata pointer itself. So callers were
forced to send xlator pointer as mydata which is opaque
(void pointer) by function prototype.

'rpcsvc_register_init' is setting svc->mydata with xlator
pointer. 'rpcsvc_register_notify' is overwriting svc->mydata
with mydata pointer. And rpc interprets svc->mydata as
xlator pointer internally. If someone passes non xlator
structure pointer to rpcsvc_register_notify as libgfchangelog
currently does, it might corrupt mydata. So interpreting opaque
mydata as xlator pointer is incorrect as it is caller's choice
to send mydata as any type of data to 'rpcsvc_register_notify'.

Maintaining two different pointers in 'rpcsvc_state' for xlator
and mydata solves the issue.

Change-Id: I7874933fefc68f3fe01d44f92016a8e4e9768378
BUG: 1215161
Signed-off-by: Kotresh HR 
Reviewed-on: http://review.gluster.org/10366
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra G 
Tested-by: Raghavendra G

quotad: Remove dead code

2014-06-30T10:00:21+00:00

client_t is created by server xlator for managing connection related
resources. Quotad doesn't do that. So no need to handle anything related
to it.

Change-Id: I83e6f9e1c57458d60529dc62086bb63642932d49
BUG: 1113403
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/8180
Reviewed-by: Krutika Dhananjay 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

features/quota: Improvements to quota

2013-11-26T18:24:02+00:00

* Two stages of quota enforcement is done:

  Soft and hard quota Upon reaching soft quota limit on the directory
  it logs/alerts in the quota daemon log (ie DEFAULT_LOG_DIR/quotad.log)
  and no more writes allowed after hard
  quota limit. After reaching the soft-limit the daemon alerts the
  user/admin repeatively for every 'alert-time', which is
  configurable.

* Quota enforcer is moved to server-side.

  It  takes care of enforcing quota. Since enforcer doesn't have the
  cluster view, it relies on another service called
  quota-aggregator. Aggregator, on query can return the size of a
  directory based on the cluster view.

  Enforcer is always loaded in the server graph and is by passed if
  the feature is not enabled.

  Options specific to enforcer:

  server-quota - Specifies whether the feature is on/off. It is used
  to by pass the quota if turned off.

  deem-statfs - If set to on, it takes quota limits into consideration
  while estimating fs size. (df command). The algorithm followed is,
  i.   Adjust statvfs based on limit configured on root.
  ii.  If limit is set on the inode passed, use size/limits on that inode to
       populate statvfs. Otherwise, use size/limits configured on root.
  iii. Upon statvfs, update the ctx->size on the inode.
  iv.  Don't let DHT aggregate, instead take the maximum of the usages from the
       subvols of the DHT, since each of it contains the complete information.

  Enforcer also makes use of gfid-to-path conversion functionality to
  work correctly when a client like nfs predominently relies on
  nameless lookups.

* Quota Aggregator acts as a thin client to provide cluster view

  Its a lightweight *gluster client* process with no mount point,
  started upon enabling quota or restarting the volume. This is a
  single process run on each brick, which can answer queries on all
  volumes in the cluster. Its volfile stored in
  GLUSTERD_DEFAULT_WORKING_DIR/quotad/quotad.vol.

Credits:
Raghavendra Bhat        
Varun Shastry           
Shishir Gowda           
Kruthika Dhananjay      
Brian Foster            
Krishnan Parthasarathi  

Change-Id: Id1cb25b414951da34c665a55f77385d482e0f9de
BUG: 969461
Signed-off-by: Raghavendra G 
Reviewed-on: http://review.gluster.org/5952
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati