glusterfs.git/xlators/features/bit-rot/src/bitd/Makefile.am, branch v3.10.8

build: out-of-tree builds generates files in the wrong directory

2016-09-18T16:34:37+00:00

And minor cleanup of a few of the Makefile.am files while we're
at it.

Rewrite the make rules to do what xdrgen does. Now we can get rid
of xdrgen.

Note 1. netbsd6's sed doesn't do -i. Why are we still running
smoke tests on netbsd6 and not netbsd7? We barely support netbsd7
as it is.

Note 2. Why is/was libgfxdr.so (.../rpc/xdr/src/...) linked with
libglusterfs? A cut-and-paste mistake? It has no references to
symbols in libglusterfs.

Note3. "/#ifndef\|#define\|#endif/" (note the '\'s) is a _basic_
regex that matches the same lines as the _extended_ regex
"/#(ifndef|define|endif)/". To match the extended regex sed needs to
be run with -r on Linux; with -E on *BSD. However NetBSD's and
FreeBSD's sed helpfully also provide -r for compatibility. Using a
basic regex avoids having to use a kludge in order to run sed with
the correct option on OS X.

Note 4. Not copying the bit of xdrgen that inserts copyright/license
boilerplate. AFAIK it's silly to pretend that machine generated
files like these can be copyrighted or need license boilerplate.
The XDR source files have their own copyright and license; and
their copyrights are bound to be more up to date than old
boilerplate inserted by a script. From what I've seen of other
Open Source projects -- e.g. gcc and its C parser files generated
by yacc and lex -- IIRC they don't bother to add copyright/license
boilerplate to their generated files.

It appears that it's a long-standing feature of make (SysV, BSD,
gnu) for out-of-tree builds to helpfully pretend that the source
files it can find in the VPATH "exist" as if they are in the $cwd.
rpcgen doesn't work well in this situation and generates files
with "bad" #include directives.

E.g. if you `rpcgen ../../../../$srcdir/rpc/xdr/src/glusterfs3-xdr.x`,
you get an #include directive in the generated .c file like this:

  ...
  #include "../../../../$srcdir/rpc/xdr/src/glusterfs3-xdr.h"
  ...

which (obviously) results in compile errors on out-of-tree build
because the (generated) header file doesn't exist at that location.
Compared to `rpcgen ./glusterfs3-xdr.x` where you get:

  ...
  #include "glusterfs3-xdr.h"
  ...

Which is what we need. We have to resort to some Stupid Make Tricks
like the addition of various .PHONY targets to work around the VPATH
"help".

Warning: When doing an in-tree build, -I$(top_builddir)/rpc/xdr/...
looks exactly like -I$(top_srcdir)/rpc/xdr/...  Don't be fooled though.
And don't delete the -I$(top_builddir)/rpc/xdr/... bits

Change-Id: Iba6ab96b2d0a17c5a7e9f92233993b318858b62e
BUG: 1330604
Signed-off-by: Kaleb S KEITHLEY 
Reviewed-on: http://review.gluster.org/14085
Tested-by: Niels de Vos 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Niels de Vos

features/bitrot: Move throttling code to libglusterfs

2016-07-18T12:03:17+00:00

Since throttling is a separate feature by itself,
move throttling code to libglusterfs.

Change-Id: If9b99885ceb46e5b1865a4af18b2a2caecf59972
BUG: 1352019
Signed-off-by: Kotresh HR 
Reviewed-on: http://review.gluster.org/14846
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Ravishankar N 
Reviewed-by: Jeff Darcy

features/bitrot: Introduce scrubber monitor thread

2016-05-02T04:33:33+00:00

The patch does following changes.

 1. Introduce scrubber monitor thread.
 2. Move scrub status related APIs to separate file
    and make part of libbitrot library.

Problem:
     Earlier, each child of the scrubber was maintaining
the state machine and hence there was no way to track
the start and end time of scrubbing as each brick has
it's own start and end time. Also each brick was maintaining
it's own timer wheel instance. It was also not possible
to get scrubbed files count per session as we could not
get last child which finishes scrubbing to reset it to
zero.

Solution:
    Introduce scrubber monitor thread. It does following.

 1. Maintains the scrubber state machine. Earlier each
    child had it's own state machine. Now, only monitor
    maintains on behalf of all it's children.
 2. Maintains the timer wheel instance. Earlier each
    child had it's own timer wheel instance. Now, only
    monitor maintains on behalf of all it's children.

As a result, we can track the scrub statistics easily
and correctly.

Change-Id: Ic6e34ffa57984bd7a5ee81f4e263342bc1d9b302
BUG: 1329211
Signed-off-by: Kotresh HR 
Reviewed-on: http://review.gluster.org/14044
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Venky Shankar

build: export minimum symbols from xlators for correct resolution

2015-12-22T17:15:01+00:00

Revisiting http://review.gluster.org/#/c/11814/, which unintentionally
introduced warnings from libtool about the xlator .so names.

According to [1], the -module option must appear in the Makefile.am
file(s); if -module is defined in a macro, e.g. in configure(.ac),
then libtool will not recognize that this is a module and will emit a
warning.

[1]
http://www.gnu.org/software/automake/manual/automake.html#Libtool-Modules

Change-Id: Ifa5f9327d18d139597791c305aa10cc4410fb078
BUG: 1248669
Signed-off-by: Kaleb S KEITHLEY 
Reviewed-on: http://review.gluster.org/13003
Tested-by: NetBSD Build System 
Tested-by: Gluster Build System 
Reviewed-by: soumya k 
Reviewed-by: Niels de Vos

build: export minimum symbols from xlators for correct resolution

2015-09-24T14:37:42+00:00

We've been lucky that we haven't had any symbol collisions until now.
Now we have a collision between the snapview-client's svc_lookup() and
libntirpc's svc_lookup() with nfs-ganesha's FSAL_GLUSTER and libgfapi.

As a short term solution all the snapview-client's FOP methods were
changed to static scope. See http://review.gluster.org/11805. This
works in snapview-client because all the FOP methods are defined in
a single source file. This solution doesn't work for other xlators
with FOP methods defined in multiple source files.

To address this we link with libtool's '-export-symbols $symbol-file'
(a wrapper around `ld --version-script ...` --- on linux anyway) and
only export the minimum required symbols from the xlator sharedlib.

N.B. the libtool man page says that the symbol file should be named
foo.sym, thus the rename of *.exports to *.sym. While foo.exports
worked, we will follow the documentation.

Signed-off-by: Kaleb S. KEITHLEY 
BUG: 1248669
Change-Id: I1de68b3e3be58ae690d8bfb2168bfc019983627c
Reviewed-on: http://review.gluster.org/11814
Tested-by: NetBSD Build System 
Tested-by: Gluster Build System 
Reviewed-by: soumya k 
Reviewed-by: Niels de Vos

features/bitrot: throttle signer

2015-07-14T09:05:19+00:00

Pass -DDBR_RATE_LIMIT_SIGNER CFLAGS to enable fixed value throttling
based on TBF to rate limit signer. The following messags is dumped
in bitd log file that this change introduces.

[
    [Rate Limit Info] "tokens/sec (rate): 131072, maxlimit: 524288"
]

Bug: 1242809
Change-Id: I063e41d4c7bcddd7a940cc175e89536cd4fe2804
Signed-off-by: Venky Shankar 
Reviewed-on: http://review.gluster.org/11641
Reviewed-by: Vijay Bellur 
Tested-by: Vijay Bellur

features/bitrot: handle scrub states via state machine

2015-06-25T12:57:22+00:00

A bunch of command line options for scrubber tempted the use of
state machine to track current state of scrubber under various
circumstances where the options could be in effect.

Change-Id: Id614bb2e6af30a90d2391ea31ae0a3edeb4e0d69
BUG: 1231619
Signed-off-by: Venky Shankar 
Reviewed-on: http://review.gluster.org/11149
Tested-by: NetBSD Build System 
Reviewed-by: Raghavendra Bhat 
Tested-by: Gluster Build System

bit-rot : New logging framework for bit-rot log message

2015-06-24T11:06:42+00:00

Change-Id: I83c494f2bb60d29495cd643659774d430325af0a
BUG: 1194640
Signed-off-by: Mohamed Ashiq 
Reviewed-on: http://review.gluster.org/10297
Tested-by: Venky Shankar 
Reviewed-by: Raghavendra Bhat 
Reviewed-by: Gaurav Kumar Garg 
Tested-by: NetBSD Build System 
Reviewed-by: Venky Shankar

features/bit-rot: Token Bucket based throttling

2015-05-07T14:14:32+00:00

BitRot daemons (signer & scrubber) are disk/cpu hoggers when left
running full throttle. Checksum calculations (especially SHA family
of hash routines) can be quite CPU intensive. Moreover periodic
disk scans performed by scrubber followed by reading data blocks
for hash calculation (which is also done by signer) generate lot
of heavy IO request(s). This causes interference with actual client
operations (be it a regular client or filesystems daemons such as
self-heal, etc..) and results in degraded system performance.

This patch introduces throttling based on Token Bucket Filtering[1].
It's a well known algorithm for checking (and ensuring) that data
transmission conform to defined limits and generally used in packet
switched networks. Linux control groups (Cgroups) uses a variant[2]
of this algorithm to provide block device IO throttling (cgroup
subsys "blkio": blk-iothrottle).

So, why not just live with Cgroups?
Cgroups is linux specific. We need to have a throttling mechanism
for other supported UNIXes. Moreover, having our own implementation
gives much more finer control in terms of tuning it for our needs
(plus the simplicity of the alogorithm itself).

Ideally, throttling should be a part of server stack (either as a
separate translator or integrated with io-threads) since that's
the point of entry for IO request(s) from *all* client(s). That
way one could selectively throttle IO request(s) based on client
PIDs (frame->root->pid), e.g., self-heal daemon, bitrot, etc..
(*actual* clients can run full throttle). This implementation
avoids that deliberately (there needs to be a much more smarter
queueing mechanism) and throttles CPU usage for hash calculations.

This patch is just the infrastructure part with no interfaces
exposed to set various throttling values. The tunable selected
here (basically hardcoded) avoids 100% CPU usage during hash
calculation (with some bursts cycles). We'd need much more
intensive test(s) to assign values for various throttling
options (lazy/normal/aggressive).

[1] https://en.wikipedia.org/wiki/Token_bucket
[2] http://en.wikipedia.org/wiki/Token_bucket#Hierarchical_token_bucket

Change-Id: Icc49af80eeab6adb60166d0810e69ef37cfe2fd8
BUG: 1207020
Signed-off-by: Venky Shankar 
Reviewed-on: http://review.gluster.org/10307
Reviewed-by: Vijay Bellur 
Tested-by: Vijay Bellur

features/bit-rot: filesystem scrubber

2015-03-24T17:55:51+00:00

Scrubber performs signature verification for objects that were
signed by signer. This is done by recalculating the signature
(using the hash algorithm the object was signed with) and
verifying it aginst the objects persisted signature. Since the
object could be undergoing IO opretaion at the time of hash
calculation, the signature may not match objects persisted
signature. Bitrot stub provides additional information about
the stalesness of an objects signature (determinted by it's
versioning mechanism). This additional bit of information is
used by scrubber to determine the staleness of the signature,
and in such cases the object is skipped verification (although
signature staleness is performed twice: once before initiation
of hash calculation and another after it (an object could be
modified after staleness checks).

The implmentation is a part of the bitrot xlator (signer) which
acts as a signer or scrubber based on a translator option. As
of now the scrub process is ever running (but has some form of
weak throttling mechanism during filesystem scan). Going forward,
there needs to be some form of scrub scheduling and IO throttling
(during hash calculation) tunables (via CLI).

Change-Id: I665ce90208f6074b98c5a1dd841ce776627cc6f9
BUG: 1170075
Original-Author: Raghavendra Bhat 
Original-Author: Venky Shankar 
Signed-off-by: Venky Shankar 
Reviewed-on: http://review.gluster.org/9914
Tested-by: Vijay Bellur 
Reviewed-by: Vijay Bellur