前面已经介绍过，glusterfs中主线为xlator，几乎每一个大的功能点，或者性能，都可以以xlator形式参与进glusterfs中，那么xlator的开发就必不可少，所以，这里介绍一下简单的向glusterfs中增加xlator的方法，首先创建一个卷testvol
代码语言：javascript复制[root@CM addxlator]# mkdir /opt/test
[root@CM addxlator]# gluster volume create testvol 192.168.0.194:/opt/test force
volume create: testvol: success: please start the volume to access data
[root@CM addxlator]# gluster volume info all
Volume Name: testvol
Type: Distribute
Volume ID: f0ef2a09-09c0-4a84-aeb6-3f2e0aebf4c2
Status: Created
Number of Bricks: 1
Transport-type: tcp
Bricks:
Brick1: 192.168.0.194:/opt/test
[root@CM addxlator]#
[root@CM addxlator]# gluster volume start testvol force
volume start: testvol: success
[root@CM addxlator]# 创建成功后，可以查看volume file中的内容
cat /var/lib/glusterd/vols/testvol/testvol-fuse.vol
代码语言：javascript复制volume testvol-client-0
type protocol/client
option transport-type tcp
option remote-subvolume /opt/test
option remote-host 192.168.0.194
end-volume
volume testvol-dht
type cluster/distribute
subvolumes testvol-client-0
end-volume
volume testvol-write-behind
type performance/write-behind
subvolumes testvol-dht
end-volume
volume testvol-read-ahead
type performance/read-ahead
subvolumes testvol-write-behind
end-volume
volume testvol-io-cache
type performance/io-cache
subvolumes testvol-read-ahead
end-volume
volume testvol-quick-read
type performance/quick-read
subvolumes testvol-io-cache
end-volume
volume testvol-open-behind
type performance/open-behind
subvolumes testvol-quick-read
end-volume
volume testvol-md-cache
type performance/md-cache
subvolumes testvol-open-behind
end-volume
volume testvol
type debug/io-stats
option count-fop-hits off
option latency-measurement off
subvolumes testvol-md-cache
end-volume这个配置为默认的配置，接下来需要将自己的xlator增加入该配置中，根据之前所提到过的xlator_dyload的过程，需要修改这个volume file，来增加xlator，修改配置如下：
代码语言：javascript复制volume testvol-client-0
type protocol/client
option transport-type tcp
option remote-subvolume /opt/test
option remote-host 192.168.0.194
end-volume
volume testvol-dht
type cluster/distribute
subvolumes testvol-client-0
end-volume
volume testvol-write-behind
type performance/write-behind
subvolumes testvol-dht
end-volume
volume testvol-read-ahead
type performance/read-ahead
subvolumes testvol-write-behind
end-volume
volume testvol-io-cache
type performance/io-cache
subvolumes testvol-read-ahead
end-volume
volume testvol-quick-read
type performance/quick-read
subvolumes testvol-io-cache
end-volume
volume testvol-open-behind
type performance/open-behind
subvolumes testvol-quick-read
end-volume
volume testvol-md-cache
type performance/md-cache
subvolumes testvol-open-behind
end-volume volume testvol-test
type debug/test
subvolumes testvol-md-cache
end-volume volume testvol
type debug/io-stats
option count-fop-hits off
option latency-measurement off
subvolumes testvol-test
end-volume可以看到，配置中多了个testvol-test这么一层，接下来将glusterfs挂载至挂载点查看输出log
代码语言：javascript复制[root@CM addxlator]#
[root@CM addxlator]# mount -t glusterfs 192.168.0.194:testvol /media
[root@CM addxlator]# 查看gluster挂载到的挂载点对应的log输出信息 cat /usr/local/var/log/glusterfs/media.log
代码语言：javascript复制[2013-06-10 11:00:29.899440] I [glusterfsd.c:1878:main] 0-/usr/local/sbin/glusterfs: Started running /usr/local/sbin/glusterfs version 3git (/usr/local/sbin/glusterfs --volfile-id=testvol --volfile-server=192.168.0.194 /media)
[2013-06-10 11:00:29.903627] I [socket.c:3515:socket_init] 0-glusterfs: SSL support is NOT enabled
[2013-06-10 11:00:29.903823] I [socket.c:3530:socket_init] 0-glusterfs: using system polling thread
[2013-06-10 11:00:29.909423] E [test.c:54:init] 0-testvol-test: test translator loaded
[2013-06-10 11:00:29.909718] I [dht-shared.c:311:dht_init_regex] 0-testvol-dht: using regex rsync-hash-regex = ^.(. ).[^.] $
[2013-06-10 11:00:29.911047] I [socket.c:3515:socket_init] 0-testvol-client-0: SSL support is NOT enabled
[2013-06-10 11:00:29.911173] I [socket.c:3530:socket_init] 0-testvol-client-0: using system polling thread
[2013-06-10 11:00:29.911218] I [client.c:2236:notify] 0-testvol-client-0: parent translators are ready, attempting connect on transport
Final graph:
------------------------------------------------------------------------------
1: volume testvol-client-0
2: type protocol/client
3: option remote-host 192.168.0.194
4: option remote-subvolume /opt/test
5: option transport-type socket
6: end-volume
7:
8: volume testvol-dht
9: type cluster/distribute
10: subvolumes testvol-client-0
11: end-volume
12:
13: volume testvol-write-behind
14: type performance/write-behind
15: subvolumes testvol-dht
16: end-volume
17:
18: volume testvol-read-ahead
19: type performance/read-ahead
20: subvolumes testvol-write-behind
21: end-volume
22:
23: volume testvol-io-cache
24: type performance/io-cache
25: subvolumes testvol-read-ahead
26: end-volume
27:
28: volume testvol-quick-read
29: type performance/quick-read
30: subvolumes testvol-io-cache
31: end-volume
32:
33: volume testvol-open-behind
34: type performance/open-behind
35: subvolumes testvol-quick-read
36: end-volume
37:
38: volume testvol-md-cache
39: type performance/md-cache
40: subvolumes testvol-open-behind
41: end-volume
42:
43: volume testvol-test
44: type debug/test
45: subvolumes testvol-md-cache
46: end-volume
47:
48: volume testvol
49: type debug/io-stats
50: option latency-measurement off
51: option count-fop-hits off
52: subvolumes testvol-test
53: end-volume
54:
------------------------------------------------------------------------------
[2013-06-10 11:00:29.914847] I [rpc-clnt.c:1675:rpc_clnt_reconfig] 0-testvol-client-0: changing port to 49152 (from 0)
[2013-06-10 11:00:29.918227] I [client-handshake.c:1658:select_server_supported_programs] 0-testvol-client-0: Using Program GlusterFS 3.3, Num (1298437), Version (330)
[2013-06-10 11:00:29.918482] I [client-handshake.c:1456:client_setvolume_cbk] 0-testvol-client-0: Connected to 192.168.0.194:49152, attached to remote volume '/opt/test'.
[2013-06-10 11:00:29.918548] I [client-handshake.c:1468:client_setvolume_cbk] 0-testvol-client-0: Server and Client lk-version numbers are not same, reopening the fds
[2013-06-10 11:00:29.923683] I [fuse-bridge.c:4767:fuse_graph_setup] 0-fuse: switched to graph 0
[2013-06-10 11:00:29.923986] I [client-handshake.c:450:client_set_lk_version_cbk] 0-testvol-client-0: Server lk version = 1
[2013-06-10 11:00:29.924164] I [fuse-bridge.c:3724:fuse_init] 0-glusterfs-fuse: FUSE inited with protocol versions: glusterfs 7.13 kernel 7.13
[2013-06-10 11:00:29.924225] E [test.c:28:test_lookup] 0-testvol-test: in test translator lookup
[2013-06-10 11:00:29.925153] E [test.c:28:test_lookup] 0-testvol-test: in test translator lookup经过查看log，可以看到test模块中的打印输出， in test translator lookup 接下来查看描述一下外挂xlator的方式 首先现在glusterfs的源代码，编译以后，在本地也就存在了glusterfs的开发环境，为了开发调试方便，可暂不将xlator存于glusterfs工程中，这时可以编写一个Makefile 首先建立一个目录
代码语言：javascript复制mkdir addxlator_sample
cd addxlator_sampleMakefile中内容可如下：
代码语言：javascript复制#Add translator into glusterfs volume file
#Author Steven Liu
#E-mail lingjiujianke@gmail.com
#Blog: http://blog.fs-linux.org
TARGET = test.so
OBJECTS = test.o
GLUSTERFS_SRC = /opt/glusterfs
GLUSTERFS_LIB = /usr/local/lib
HOST_OS = HF_LINUX_HOST_OS
CFLAGS = -fPIC -Wall -O0 -g
-DHAVE_CONFIG_H -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -D$(HOST_OS)
-I$(GLUSTERFS_SRC) -I$(GLUSTERFS_SRC)/libglusterfs/src
-I$(GLUSTERFS_SRC)/contrib/uuid
LDFLAGS = -shared -nostartfiles -L$(GLUSTERFS_LIB) -lglusterfs -lpthread
$(TARGET): $(OBJECTS)
$(CC) $(OBJECTS) $(LDFLAGS) -o $(TARGET)
clean:
rm -rf $(TARGET) $(OBJECTS)Makefile编写完成之后，需要OBJECTS，这时需要编写test.c来保证编译通过，当然，test这个xlator也需要在这里生成
代码语言：javascript复制#ifndef _CONFIG_H
#define _CONFIG_H
#include "config.h"
#include "xlator.h"
#endif
#include
#include
#include "glusterfs.h"
#include "xlator.h"
#include
#include "defaults.h"
#include "logging.h"
int test_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
int32_t op_ret, int32_t op_errno,
inode_t *inode, struct iatt *buf,
dict_t *xdata, struct iatt *postparent)
{
STACK_UNWIND_STRICT (lookup, frame, op_ret, op_errno, inode, buf, xdata,
postparent);
return 0;
}
static int test_lookup(call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
{
gf_log(this->name, GF_LOG_ERROR, "in test translator lookup");
STACK_WIND (frame, test_lookup_cbk,
FIRST_CHILD(this), FIRST_CHILD(this)->fops->lookup,
loc, xdata);
return 0;
}
static int test_stat (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
{
gf_log(this->name, GF_LOG_ERROR, "in test translator stat");
return 0;
}
int
reconfigure (xlator_t *this, dict_t *options)
{
return 0;
}
int
init (xlator_t *this)
{
struct ios_conf *conf = NULL;
int ret = -1;
gf_log (this->name, GF_LOG_ERROR, "test translator loaded");
if (!this)
return -1;
if (!this->children) {
gf_log (this->name, GF_LOG_ERROR,
"test translator requires atleast one subvolume");
return -1;
}
if (!this->parents) {
gf_log (this->name, GF_LOG_ERROR, "dangling volume. check volfile ");
}
conf = this->private;
this->private = conf;
ret = 0;
return ret;
}
void
fini (xlator_t *this)
{
struct ios_conf *conf = NULL;
if (!this)
return;
conf = this->private;
if (!conf)
return;
this->private = NULL;
GF_FREE(conf);
gf_log (this->name, GF_LOG_ERROR, "test translator unloaded");
return;
}
int
notify (xlator_t *this, int32_t event, void *data, ...)
{
default_notify (this, event, data);
return 0;
}
struct xlator_fops fops = {
.stat = test_stat,
.lookup = test_lookup,
};
struct xlator_cbks cbks = {
};
struct volume_options options[] = {
};目前仅用于测试的xlator而已，所以自己定义了lookup与stat，还有lookup_cbk，其他的并未定义，全部走default，这个原理在之前已经提到过。 然后执行make既可生成对应的xlator文件
代码语言：javascript复制Makefile test.c test.o test.so将test.so复制至/usr/local/lib/glusterfs/3git/xlator/debug中 然后执行glusterfs的客户端，mount至挂载节点，如果成功，可以查看log，整个过程成功矣~~！
