glusterfs-snapshot.git/xlators/protocol/client, branch development

glusterfs: zerofill support

2013-11-11T05:25:49+00:00

Add support for a new ZEROFILL fop. Zerofill writes zeroes to a file in
the specified range. This fop will be useful when a whole file needs to
be initialized with zero (could be useful for zero filled VM disk image
provisioning or  during scrubbing of VM disk images).

Client/application can issue this FOP for zeroing out. Gluster server
will zero out required range of bytes ie server offloaded zeroing. In
the absence of this fop,  client/application has to repetitively issue
write (zero) fop to the server, which is very inefficient method because
of the overheads involved in RPC calls  and acknowledgements.

WRITESAME is a  SCSI T10 command that takes a block of data as input and
writes the same data to other blocks and this write is handled
completely within the storage and hence is known as offload . Linux ,now
has support for SCSI WRITESAME command which is exposed to the user in
the form of BLKZEROOUT ioctl.  BD Xlator can exploit BLKZEROOUT ioctl to
implement this fop. Thus zeroing out operations can be completely
offloaded to the storage device , making it highly efficient.

The fop takes two arguments offset and size. It zeroes out 'size' number
of bytes in an opened file starting from 'offset' position.

This patch adds zerofill support to the following areas:
	- libglusterfs
	- io-stats
	- performance/md-cache,open-behind
	- quota
	- cluster/afr,dht,stripe
	- rpc/xdr
	- protocol/client,server
	- io-threads
	- marker
	- storage/posix
	- libgfapi

Client applications can exloit this fop by using glfs_zerofill introduced in
libgfapi.FUSE support to this fop has not been added as there is no system call
for this fop.

Changes from previous version 3:
* Removed redundant memory failure log messages

Changes from previous version 2:
* Rebased and fixed build error

Changes from previous version 1:
* Rebased for latest master

TODO :
     * Add zerofill support to trace xlator
     * Expose zerofill capability as part of gluster volume info

Here is a performance comparison of server offloaded zeofill vs zeroing
out using repeated writes.

[root@llmvm02 remote]# time ./offloaded aakash-test log 20

real	3m34.155s
user	0m0.018s
sys	0m0.040s
[root@llmvm02 remote]# time ./manually aakash-test log 20

real	4m23.043s
user	0m2.197s
sys	0m14.457s
[root@llmvm02 remote]# time ./offloaded aakash-test log 25;

real	4m28.363s
user	0m0.021s
sys	0m0.025s
[root@llmvm02 remote]# time ./manually aakash-test log 25

real	5m34.278s
user	0m2.957s
sys	0m18.808s

The argument log is a file which we want to set for logging purpose and
the third argument is size in GB .

As we can see there is a performance improvement of around 20% with this
fop.

Change-Id: I081159f5f7edde0ddb78169fb4c21c776ec91a18
BUG: 1028673
Signed-off-by: Aakash Lal Das 
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/5327
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

libglusterfs: Add monotonic clocking counter for timer thread

2013-10-15T07:14:57+00:00

gettimeofday() returns the current wall clock time and timezone.
Using these functions in order to measure the passage of time
(how long an operation took) therefore seems like a no-brainer.

This time suffer's from some limitations:

a. They have a low resolution: “High-performance” timing by
definition, requires clock resolutions into the microseconds
or better.

b. They can jump forwards and backwards in time: Computer
clocks all tick at slightly different rates, which causes
the time to drift. Most systems have NTP enabled which
periodically adjusts the system clock to keep them in sync
with “actual” time. The adjustment can cause the clock to
suddenly jump forward (artificially inflating your timing
numbers) or jump backwards (causing your timing calculations
to go negative or hugely positive). In such cases timer
thread could go into an infinite loop.

From 'man gettimeofday':
----------
..
..
The time returned by gettimeofday() is affected by discontinuous
jumps in the system time (e.g., if the system administrator manually
changes the system time).  If you need a monotonically increasing
clock, see clock_gettime(2).
..
..
----------

Rationale:

For calculating interval timing for Timer thread, all that’s
needed should be clock as a simple counter that increments
at a stable rate.

This is necessary to avoid the jumps which are caused by using
"wall time", this counter must be monotonic that can never
“tick” backwards, ever.

Change-Id: I701d31e71a85a73d21a6c5cd15583e7a5a645eeb
BUG: 1017993
Signed-off-by: Harshavardhana 
Reviewed-on: http://review.gluster.org/6070
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

protocol/rpc: move latest added procedures to the end of the array

2013-06-17T16:34:56+00:00

While looking at the newly introduced procedures FALLOCATE and DISCARD,
it seems that these were added with already existing procedure numbers.
This makes the protocol incompatible with existing roll-outs.

It is very confusing when new procedures are added somewhere in the
middle of the array. This will cause the number of existing procedures
to change. It is much preferred to add new procedures at the end of the
array. This changes not only corrects the enum that generates the
procedure numbers, but also the ordering in the client and server
fops-array for clarity.

Correcting this greatly simplifies adding support for these new
procedures in Wireshark and will prevent confusion to the people reading
network traces (with or without Wireshark).

Change-Id: Ib9e7978531d016c7230d756b855cb94cb0793b0f
BUG: 974976
Signed-off-by: Niels de Vos 
Reviewed-on: http://review.gluster.org/5215
Tested-by: Gluster Build System 
Reviewed-by: Brian Foster 
Reviewed-by: Anand Avati

glusterfs: discard (hole punch) support

2013-06-13T21:37:43+00:00

Add support for the DISCARD file operation. Discard punches a hole
in a file in the provided range. Block de-allocation is implemented
via fallocate() (as requested via fuse and passed on to the brick
fs) but a separate fop is created within gluster to emphasize the
fact that discard changes file data (the discarded region is
replaced with zeroes) and must invalidate caches where appropriate.

BUG: 963678
Change-Id: I34633a0bfff2187afeab4292a15f3cc9adf261af
Signed-off-by: Brian Foster 
Reviewed-on: http://review.gluster.org/5090
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

gluster: add fallocate fop support

2013-06-13T21:37:21+00:00

Implement support for the fallocate file operation. fallocate
allocates blocks for a particular inode such that future writes
to the associated region of the file are guaranteed not to fail
with ENOSPC.

This patch adds fallocate support to the following areas:

	- libglusterfs
	- mount/fuse
	- io-stats
	- performance/md-cache,open-behind
	- quota
	- cluster/afr,dht,stripe
	- rpc/xdr
	- protocol/client,server
	- io-threads
	- marker
	- storage/posix
	- libgfapi

BUG: 949242
Change-Id: Ice8e61351f9d6115c5df68768bc844abbf0ce8bd
Signed-off-by: Brian Foster 
Reviewed-on: http://review.gluster.org/4969
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

protocol/client: Prevent excessive logging of client's "disconnect" messages.

2013-05-28T11:38:25+00:00

Problem: Currently when gluster volume start force is executed, client process
         will talk to glusterd to get the port of the brick. But if brick's path
         is not available it cannot return brick's port. So client process will
         keep connecting and disconnecting from glusterd for port-query which
         is ultimately responsible for execssive logging of disconnect messages.

Fix:     Message will be logged just once at INFO level after the first
         disconnect from glusterd. Afterwards "disconnect" messages will be
         logged in DEBUG mode.

Change-Id: I2b787f3820b5da45e090c562e5698fcfe24a02cd
BUG: 959969
Signed-off-by: Venkatesh Somyajulu 
Reviewed-on: http://review.gluster.org/4953
Reviewed-by: Amar Tumballi 
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

logging: Fix to avoid excessive logging.

2013-05-28T08:24:42+00:00

mem_get function: Log message related to mem_pool 
calloc is removed  as its been calculated in mempool
'stats'.  This messgae is consuming nearly half of 
the total log messages in DEBUG mode.

dht_hash_compute function: Changed log level from DEBUG 
to TRACE.

client_fdctx_destroy function: Changed log  level from DEBUG 
to TRACE.

Change-Id: Ic948db0419e76df4e95ebd0cabaf66eadbaada6b
BUG: 966851
Signed-off-by: Venkatesh Somyajulu 
Reviewed-on: http://review.gluster.org/5086
Reviewed-by: Amar Tumballi 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

client: Reset remote-port on first disconnect from brick

2013-05-17T02:20:25+00:00

Change-Id: I8940358788a7c4f8be81d705749f668a43422b8e
BUG: 962930
Signed-off-by: Krishnan Parthasarathi 
Reviewed-on: http://review.gluster.org/4988
Reviewed-by: Amar Tumballi 
Tested-by: Gluster Build System 
Reviewed-by: Jeff Darcy

protocol/client: Print valid loc identifiers

2013-04-03T22:22:32+00:00

Change-Id: I45f91105862a2484b8906a7a63b98ab4aaf80d05
BUG: 924643
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/4683
Reviewed-by: Jeff Darcy 
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

Use proper libtool option -avoid-version instead of bogus -avoidversion

2013-02-07T23:12:56+00:00

Change-Id: I1c9541058c7d07786539a3266ca125a6a15287d8
BUG: 859835
Signed-off-by: Anand Avati 
Original-author: Kacper Kowalik (Xarthisius) 
Signed-off-by: Kacper Kowalik (Xarthisius) 
Reviewed-on: http://review.gluster.org/3967
Tested-by: Gluster Build System