glusterfs.git/tests/bugs/io-cache, branch v3.12.5

core: run many bricks within one glusterfsd process

2017-01-31T00:13:58+00:00

This patch adds support for multiple brick translator stacks running
in a single brick server process.  This reduces our per-brick memory usage by
approximately 3x, and our appetite for TCP ports even more.  It also creates
potential to avoid process/thread thrashing, and to improve QoS by scheduling
more carefully across the bricks, but realizing that potential will require
further work.

Multiplexing is controlled by the "cluster.brick-multiplex" global option.  By
default it's off, and bricks are started in separate processes as before.  If
multiplexing is enabled, then *compatible* bricks (mostly those with the same
transport options) will be started in the same process.

Change-Id: I45059454e51d6f4cbb29a4953359c09a408695cb
BUG: 1385758
Signed-off-by: Jeff Darcy 
Reviewed-on: https://review.gluster.org/14763
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Vijay Bellur

libglusterfs: Fix a read hang

2016-11-29T03:59:08+00:00

Issue:
=====
In certain cases, there was no unwind of read
from read-ahead xlator, thus resulting in hang.

RCA:
====
In certain cases, ioc_readv() issues STACK_WIND_TAIL() instead
of STACK_WIND(). One such case is when inode_ctx for that file
is not present (can happen if readdirp was called, and populates
md-cache and serves all the lookups from cache).

Consider the following graph:
...
io-cache (parent)
   |
readdir-ahead
   |
read-ahead
...

Below is the code snippet of ioc_readv calling STACK_WIND_TAIL:
ioc_readv()
{
...
 if (!inode_ctx)
   STACK_WIND_TAIL (frame, FIRST_CHILD (frame->this),
                    FIRST_CHILD (frame->this)->fops->readv, fd,
                    size, offset, flags, xdata);
   /* Ideally, this stack_wind should wind to readdir-ahead:readv()
      but it winds to read-ahead:readv(). See below for
      explaination.
    */
...
}

STACK_WIND_TAIL (frame, obj, fn, ...)
{
  frame->this = obj;
  /* for the above mentioned graph, frame->this will be readdir-ahead
   * frame->this = FIRST_CHILD (frame->this) i.e. readdir-ahead, which
   * is as expected
   */
  ...
  THIS = obj;
  /* THIS will be read-ahead instead of readdir-ahead!, as obj expands
   * to "FIRST_CHILD (frame->this)" and frame->this was pointing
   * to readdir-ahead in the previous statement.
   */
  ...
  fn (frame, obj, params);
  /* fn will call read-ahead:readv() instead of readdir-ahead:readv()!
   * as fn expands to "FIRST_CHILD (frame->this)->fops->readv" and
   * frame->this was pointing ro readdir-ahead in the first statement
   */
  ...
}

Thus, the readdir-ahead's readv() implementation will be skipped, and
ra_readv() will be called with frame->this = "readdir-ahead" and
this = "read-ahead". This can lead to corruption / hang / other problems.
But in this perticular case, when 'frame->this' and 'this' passed
to ra_readv() doesn't match, it causes ra_readv() to call ra_readv()
again!. Thus the logic of read-ahead readv() falls apart and leads to
hang.

Solution:
=========
Modify STACK_WIND_TAIL() as:
STACK_WIND_TAIL (frame, obj, fn, ...)
{
  next_xl = obj /* resolve obj as the variables passed in obj macro
                   can be overwritten in the further instrucions */
  next_xl_fn = fn /* resolve fn and store in a tmp variable, before
                     modifying any variables */
  frame->this = next_xl;
  ...
  THIS = next_xl;
  ...
  next_xl_fn (frame, next_xl, params);
  ...
}

As a part of http://review.gluster.org/15901/ the caller io-cache
was fixed.

BUG: 1388292
Change-Id: Ie662ac8f18fa16909376f1e59387bc5b886bd0f9
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15923
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Rajesh Joseph 
CentOS-regression: Gluster Build System 
Reviewed-by: Raghavendra G

io-cache: Fix a read hang

2016-11-23T13:11:07+00:00

Issue:
=====
In certain cases, there was no unwind of read
from read-ahead xlator, thus resulting in hang.

RCA:
====
In certain cases, ioc_readv() issues STACK_WIND_TAIL() instead
of STACK_WIND(). One such case is when inode_ctx for that file
is not present (can happen if readdirp was called, and populates
md-cache and serves all the lookups from cache).

Consider the following graph:
...
io-cache (parent)
   |
readdir-ahead
   |
read-ahead
...

Below is the code snippet of ioc_readv calling STACK_WIND_TAIL:
ioc_readv()
{
...
 if (!inode_ctx)
   STACK_WIND_TAIL (frame, FIRST_CHILD (frame->this),
                    FIRST_CHILD (frame->this)->fops->readv, fd,
                    size, offset, flags, xdata);
   /* Ideally, this stack_wind should wind to readdir-ahead:readv()
      but it winds to read-ahead:readv(). See below for
      explaination.
    */
...
}

STACK_WIND_TAIL (frame, obj, fn, ...)
{
  frame->this = obj;
  /* for the above mentioned graph, frame->this will be readdir-ahead
   * frame->this = FIRST_CHILD (frame->this) i.e. readdir-ahead, which
   * is as expected
   */
  ...
  THIS = obj;
  /* THIS will be read-ahead instead of readdir-ahead!, as obj expands
   * to "FIRST_CHILD (frame->this)" and frame->this was pointing
   * to readdir-ahead in the previous statement.
   */
  ...
  fn (frame, obj, params);
  /* fn will call read-ahead:readv() instead of readdir-ahead:readv()!
   * as fn expands to "FIRST_CHILD (frame->this)->fops->readv" and
   * frame->this was pointing ro readdir-ahead in the first statement
   */
  ...
}

Thus, the readdir-ahead's readv() implementation will be skipped, and
ra_readv() will be called with frame->this = "readdir-ahead" and
this = "read-ahead". This can lead to corruption / hang / other problems.
But in this perticular case, when 'frame->this' and 'this' passed
to ra_readv() doesn't match, it causes ra_readv() to call ra_readv()
again!. Thus the logic of read-ahead readv() falls apart and leads to
hang.

Solution:
=========
Ideally, STACK_WIND_TAIL() should be modified as:
STACK_WIND_TAIL (frame, obj, fn, ...)
{
  next_xl = obj /* resolve obj as the variables passed in obj macro
                   can be overwritten in the further instrucions */
  next_xl_fn = fn /* resolve fn and store in a tmp variable, before
                     modifying any variables */
  frame->this = next_xl;
  ...
  THIS = next_xl;
  ...
  next_xl_fn (frame, next_xl, params);
  ...
}
But for this solution, knowing the type of variable 'next_xl_fn' is
a challenge and is not easy. Hence just modifying all the existing
callers to pass "FIRST_CHILD (this)" as obj, instead of
"FIRST_CHILD (frame->this)".

Change-Id: I179ffe3d1f154bc5a1935fd2ee44e912eb0fbb61
BUG: 1388292
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15901
Smoke: Gluster Build System 
Reviewed-by: Raghavendra G 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

tests: move all test-cases into component subdirectories

2015-01-06T11:24:24+00:00

There are around 300 regression tests, 250 being in tests/bugs. Running
partial set of tests/bugs is not easy because this is a flat directory
with almost all tests inside.

It would be valuable to make partial test/bugs easier, and allow the use
of mulitple build hosts for a single commit, each running a subset of
the tests for a quicker result.

Additional changes made:
- correct the include path for *.rc shell libraries and *.py utils
- make the testcases pass checkpatch
- arequal-checksum in afr/self-heal.t was never executed, now it is
- include.rc now complains loudly if it fails to find env.rc

Change-Id: I26ffd067e9853d3be1fd63b2f37d8aa0fd1b4fea
BUG: 1178685
Reported-by: Emmanuel Dreyfus 
Reported-by: Atin Mukherjee 
URL: http://www.gluster.org/pipermail/gluster-devel/2014-December/043414.html
Signed-off-by: Niels de Vos 
Reviewed-on: http://review.gluster.org/9353
Reviewed-by: Kaleb KEITHLEY 
Reviewed-by: Emmanuel Dreyfus 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur