glusterfs.git/xlators/cluster/dht/src/dht-shared.c, branch v3.7.0alpha0

dht : coverity fixes

2015-04-07T10:52:05+00:00

CID : 1124352,1124365 (unchecked return value),
      1124377 ( logically dead code),
      1124511 (null dereference)

Change-Id: I61e029a078559cfe15d36bf0aa53418f6214e5cb
BUG: 789278
Signed-off-by: Manikandan Selvaganesh 
Reviewed-on: http://review.gluster.org/9622
Tested-by: Gluster Build System 
Reviewed-by: Shyamsundar Ranganathan 
Reviewed-by: Kaleb KEITHLEY 
Reviewed-by: N Balachandran 
Reviewed-by: Vijay Bellur

Avoid conflict between contrib/uuid and system uuid

2015-04-04T17:48:35+00:00

glusterfs relies on Linux uuid implementation, which
API is incompatible with most other systems's uuid. As
a result, libglusterfs has to embed contrib/uuid,
which is the Linux implementation, on non Linux systems.
This implementation is incompatible with systtem's
built in, but the symbols have the same names.

Usually this is not a problem because when we link
with -lglusterfs, libc's symbols are trumped. However
there is a problem when a program not linked with
-lglusterfs will dlopen() glusterfs component. In
such a case, libc's uuid implementation is already
loaded in the calling program, and it will be used
instead of libglusterfs's implementation, causing
crashes.

A possible workaround is to use pre-load libglusterfs
in the calling program (using LD_PRELOAD on NetBSD for
instance), but such a mechanism is not portable, nor
is it flexible. A much better approach is to rename
libglusterfs's uuid_* functions to gf_uuid_* to avoid
any possible conflict. This is what this change attempts.

BUG: 1206587
Change-Id: I9ccd3e13afed1c7fc18508e92c7beb0f5d49f31a
Signed-off-by: Emmanuel Dreyfus 
Reviewed-on: http://review.gluster.org/10017
Tested-by: Gluster Build System 
Reviewed-by: Niels de Vos

DHT: move regular expression log message to DEBUG

2015-04-02T10:24:01+00:00

Change-Id: I8652208aa2c3a600816c911a9e8af557c67d37c4
BUG: 1197585
Signed-off-by: vmallika 
Reviewed-on: http://review.gluster.org/9777
Tested-by: Gluster Build System 
Reviewed-by: Shyamsundar Ranganathan 
Reviewed-by: Raghavendra G 
Tested-by: Raghavendra G

Gfdb Query Fix and Volume option fix

2015-03-30T20:39:20+00:00

1) Query fix in find_changed_with_freq()
2) Volume option typo fix for write_freq_threshold
   and read_freq_threshold

Change-Id: I38e154818178aab412b2d7b2914cd29acef66ffb
BUG: 1207343
Signed-off-by: Joseph Fernandes 
Reviewed-on: http://review.gluster.org/10050
Reviewed-by: Dan Lambright 
Tested-by: Gluster Build System 
Reviewed-by: Niels de Vos

cluster/dht: Add tier translator.

2015-03-21T16:50:29+00:00

The tier translator shares most of DHT's code. It differs in how
subvolumes are chosen for I/Os, and how file migration (cache promotion
and demotion) is managed. That different functionality is split to either
DHT or tier logic according to the "tier_methods" structure.

A cache promotion and demotion thread is created in a manner
similar to the rebalance daemon. The thread operates a timing
wheel which periodically checks for promotion and demotion candidates
(files). Candidates are queued and then migrated. Candidates must exist on
the same node as the daemon and meet other critera per caching policies.

This patch has two authors (Dan Lambright and Joseph Fernandes). Dan
did the DHT changes and Joe wrote the cache policies. The fix depends on
DHT readidr changes and the database library which have been submitted
separately.  Header files in libglusterfs/src/gfdb should be reviewed in
patch 9683.

For more background and design see the feature page [1].

[1]
http://www.gluster.org/community/documentation/index.php/Features/data-classification

Change-Id: Icc26c517ccecf5c42aef039f5b9c6f7afe83e46c
BUG: 1194753
Signed-off-by: Dan Lambright 
Reviewed-on: http://review.gluster.org/9724
Reviewed-by: Vijay Bellur 
Tested-by: Vijay Bellur

cluster/dht: Change the subvolume encoding in d_off to be a "global"

2015-03-18T11:47:41+00:00

position in the graph rather than relative (local) to a particular
translator.

Encoding the volume in this way allows a single translator to manage
which brick is currently being scanned for directory entries. Using a
single translator minimizes allocated bits in the d_off. It also allows
multiple DHT translators in the same graph to have a common frame of
reference (the graph position) for which brick is being read. Multiple
DHT translators are needed for the Tiering feature.

The fix builds off a previous change (9332) which removed subvolume
encoding from AFR. The fix makes an equivalent change to the EC
translator.

More background can be found in fix 9332 and gluster-dev discussions [1].

DHT and AFR/EC are responsibile (as before) for choosing which brick to
enumerate directory entries in over the readdir lifecycle.

The client translator receiving the readdir fop encodes the dht_t. It
is referred to as the "leaf node" in the graph and corresponds to the
brick being scanned.

When DHT decodes the d_off, it translates the leaf node to a local
subvolume, which represents the next node in the graph leading to
the brick.

Tracking of leaf nodes is done in common utility functions. Leaf nodes
counts and positional information are updated on a graph switch.

[1] www.gluster.org/pipermail/gluster-devel/2015-January/043592.html

Change-Id: Iaf0ea86d7046b1ceadbad69d88707b243077ebc8
BUG: 1190734
Signed-off-by: Dan Lambright 
Reviewed-on: http://review.gluster.org/9688
Reviewed-by: Xavier Hernandez 
Reviewed-by: Krishnan Parthasarathi 
Reviewed-by: Vijay Bellur 
Tested-by: Vijay Bellur

cluster/dht: introduce locking api.

2014-08-26T11:56:29+00:00

Change-Id: I41389ba91951d3e63e617aa32cd0bee848261c72
BUG: 1130888
Signed-off-by: Raghavendra G 
Reviewed-on: http://review.gluster.org/8521
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

dht: support heterogeneous brick sizes

2014-07-12T16:20:52+00:00

Calculation of layouts now considers the size of each brick, so that
smaller bricks don't get an "unfair" share of allocations and start
returning ENOSPC while the larger bricks still have plenty of space.

The observation has been made that some clients might get ENOTCONN when
trying to fetch disk-size information, and end up calculating layouts
differently.  The following meta-observations can be made.

(1) This scenario is extremely unlikely in configurations with AFR.

(2) The most likely consequence of this scenario is that some files will
be placed sub-optimally by the client with the obsolete (non-weighted)
layout.  They'll still be found anyway, so this isn't a show stopper.

(3) Without this patch it's *guaranteed* that some files will be placed
sub-optimally, because any layout that fails to account for brick sizes
is sub-optimal.

(4) We shouldn't be doing fix-layout from two nodes simultaneously
anyway.  That's inefficient at best.  Any instances of such behavior are
separate bugs, which should be fixed separately.

(5) In the most extreme edge case, two nodes doing weighted and
non-weighted layout fixes could race and end up creating an internally
inconsistent layout.  This condition is still transient; it will be
detected and repaired automatically the next time anyone fetches the
layout.  (If it's not that's also a preexisting bug that can show up in
other contexts.)

In conclusion, it's not the purpose of this patch to fix bugs elsewhere
in DHT.  Its purpose is to make life incrementally better for users who
add new hardware with larger disks etc. than the older equipment.  It's
only one part of an ongoing process to improve layout management and
repair, all the way up to support for multiple hash rings or tiering.

Change-Id: I05eb6f9eface9cdaf8622e0260c8c7f29020447f
BUG: 1114680
Signed-off-by: Jeff Darcy 
Reviewed-on: http://review.gluster.org/8093
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra G 
Reviewed-by: Shyamsundar Ranganathan 
Reviewed-by: Vijay Bellur

Cluster/DHT : Logging changes

2014-06-19T05:59:57+00:00

Removed trailing spaces from the code

Change-Id: I427c9a01b514824f903e301863c2c29071db6483
BUG: 1075611
Signed-off-by: Nithya Balachandran 
Reviewed-on: http://review.gluster.org/8096
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

cluster/dht: Bring option to choose gfid or name based hashing

2014-06-17T12:26:27+00:00

Change-Id: I11794eb2adceb88e75864aede450e904431a6273
BUG: 1095888
Signed-off-by: Venkatesh Somyajulu 
Reviewed-on: http://review.gluster.org/8049
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur