初涉Bcache（3）

这篇文章讲解如何编译bcache-tools与编译bcache.ko。

编译bcache-tools

第一步 下载源码

此处提供一处下载地址：git clone http://evilpiepirate.org/git/bcache-tools.git

第二步 make

[root@mongodb bcache-tools]# make
cc -O2 -Wall -g `pkg-config --cflags uuid blkid`   -c -o bcache.o bcache.c
cc -O2 -Wall -g `pkg-config --cflags uuid blkid`    make-bcache.c bcache.o  `pkg-config --libs uuid blkid` -o make-bcache
cc -O2 -Wall -g `pkg-config --cflags uuid blkid`    probe-bcache.c  `pkg-config --libs uuid blkid` -o probe-bcache
cc -O2 -Wall -g -std=gnu99    bcache-super-show.c bcache.o  `pkg-config --libs uuid` -o bcache-super-show
cc -O2 -Wall -g   -c -o bcache-register.o bcache-register.c
cc   bcache-register.o   -o bcache-register
[root@mongodb bcache-tools]#

第三步 make install

[root@mongodb bcache-tools]# make install
install -m0755 make-bcache bcache-super-show	/usr/sbin/
install -m0755 probe-bcache bcache-register		/lib/udev/
install -m0644 69-bcache.rules	/lib/udev/rules.d/
install -m0644 -- *.8 /usr/share/man/man8/
install -D -m0755 initramfs/hook	/usr/share/initramfs-tools/hooks/bcache
install -D -m0755 initcpio/install	/usr/lib/initcpio/install/bcache
install -D -m0755 dracut/module-setup.sh /lib/dracut/modules.d/90bcache/module-setup.sh
[root@mongodb bcache-tools]#

最后生成了四个工具：
make-bcache
bcache-register
bcache-super-show
probe-bcache

编译bcache.ko（此处以centos为例）

第一步 下载bcache内核源码

自行上网下载（无法找到，私信我）

第二步 解压源码包

[root@AutoCloud bcache]# tar -xf src_bache.tar.gz 
[root@AutoCloud bcache]#

第三步 拷贝文件到指定目录

[root@AutoCloud src_bcache]# cp include/uapi/linux/bcache.h /usr/src/kernels/3.10.0-1127.el7.x86_64/include/uapi/linux/
[root@AutoCloud src_bcache]#
[root@AutoCloud src_bcache]# cp include/trace/events/bcache.h /usr/src/kernels/3.10.0-1127.el7.x86_64/include/trace/events/
cp: overwrite ‘/usr/src/kernels/3.10.0-1127.el7.x86_64/include/trace/events/bcache.h’? y
[root@AutoCloud src_bcache]#

第四步 生成Makefile

[root@AutoCloud src_bcache]# vi Makefile 

KDIR:=/lib/modules/$(shell uname -r)/build
PWD:=$(shell pwd)/drivers/md/bcache

default:
	$(MAKE) -e CONFIG_BCACHE=m -C $(KDIR) M=$(PWD) modules
clean:
	rm -rf .*.cmd *.o *.mod.c *.ko .tmp_versions *.order *symvers *Module.markers

第五步 make

[root@AutoCloud src_bcache]# make
make -e CONFIG_BCACHE=m -C /lib/modules/3.10.0-1127.el7.x86_64/build M=/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache modules
make[1]: Entering directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
make[2]: Entering directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/alloc.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/bset.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/btree.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/closure.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/debug.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/extents.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/io.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/journal.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/movinggc.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.o
In file included from /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/bset.h:8:0,
                 from /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/bcache.h:190,
                 from /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:9:
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c: In function ‘add_sequential’:
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:357:12: error: ‘struct task_struct’ has no member named ‘sequential_io_avg’
  ewma_add(t->sequential_io_avg,
            ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/util.h:440:3: note: in definition of macro ‘ewma_add’
  (ewma) *= (weight) - 1;      \
   ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:357:12: error: ‘struct task_struct’ has no member named ‘sequential_io_avg’
  ewma_add(t->sequential_io_avg,
            ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/util.h:441:3: note: in definition of macro ‘ewma_add’
  (ewma) += (val) << factor;     \
   ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:358:5: error: ‘struct task_struct’ has no member named ‘sequential_io’
    t->sequential_io, 8, 0);
     ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/util.h:441:13: note: in definition of macro ‘ewma_add’
  (ewma) += (val) << factor;     \
             ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:357:12: error: ‘struct task_struct’ has no member named ‘sequential_io_avg’
  ewma_add(t->sequential_io_avg,
            ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/util.h:442:3: note: in definition of macro ‘ewma_add’
  (ewma) /= (weight);      \
   ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:357:12: error: ‘struct task_struct’ has no member named ‘sequential_io_avg’
  ewma_add(t->sequential_io_avg,
            ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/util.h:443:3: note: in definition of macro ‘ewma_add’
  (ewma) >> factor;      \
   ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:360:3: error: ‘struct task_struct’ has no member named ‘sequential_io’
  t->sequential_io = 0;
   ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c: In function ‘check_should_bypass’:
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:425:6: error: ‘struct task_struct’ has no member named ‘sequential_io’
  task->sequential_io  = i->sequential;
      ^
In file included from include/asm-generic/bug.h:15:0,
                 from ./arch/x86/include/asm/bug.h:38,
                 from include/linux/bug.h:4,
                 from include/linux/thread_info.h:11,
                 from include/linux/preempt.h:9,
                 from include/linux/spinlock.h:50,
                 from include/linux/wait.h:7,
                 from include/linux/fs.h:6,
                 from include/linux/highmem.h:4,
                 from include/linux/bio.h:23,
                 from /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/bcache.h:181,
                 from /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:9:
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:433:20: error: ‘struct task_struct’ has no member named ‘sequential_i’
  sectors = max(task->sequential_io,
                    ^
include/linux/kernel.h:793:9: note: in definition of macro ‘max’
  typeof(x) _max1 = (x);   \
         ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:433:20: error: ‘struct task_struct’ has no member named ‘sequential_i’
  sectors = max(task->sequential_io,
                    ^
include/linux/kernel.h:793:21: note: in definition of macro ‘max’
  typeof(x) _max1 = (x);   \
                     ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:434:13: error: ‘struct task_struct’ has no member named ‘sequential_io_avg’
         task->sequential_io_avg) >> 9;
             ^
include/linux/kernel.h:794:9: note: in definition of macro ‘max’
  typeof(y) _max2 = (y);   \
         ^
/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.c:434:13: error: ‘struct task_struct’ has no member named ‘sequential_io_avg’
         task->sequential_io_avg) >> 9;
             ^
include/linux/kernel.h:794:21: note: in definition of macro ‘max’
  typeof(y) _max2 = (y);   \
                     ^
make[2]: *** [/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.o] Error 1
make[2]: Leaving directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
make[1]: *** [_module_/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache] Error 2
make[1]: Leaving directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
make: *** [default] Error 2
[root@AutoCloud src_bcache]#

直接编译发现错误，没有发现sequential_io_avg。如何解决呢？
编辑drivers/md/bcache/Makefile文件

[root@AutoCloud src_bcache]# vi drivers/md/bcache/Makefile 


obj-$(CONFIG_BCACHE)    += bcache.o

bcache-y                := alloc.o bset.o btree.o closure.o debug.o extents.o\
        io.o journal.o movinggc.o request.o stats.o super.o sysfs.o trace.o\
        util.o writeback.o

CFLAGS_request.o        += -Iblock -DCONFIG_BCACHE

加上-DCONFIG_BCACHE。
再进行编译

[root@AutoCloud src_bcache]# make
make -e CONFIG_BCACHE=m -C /lib/modules/3.10.0-1127.el7.x86_64/build M=/opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache modules
make[1]: Entering directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
make[2]: Entering directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/request.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/stats.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/super.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/sysfs.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/trace.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/util.o
  CC [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/writeback.o
  LD [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/bcache.o
make[2]: Leaving directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
  Building modules, stage 2.
make[2]: Entering directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
  MODPOST 1 modules
  CC      /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/bcache.mod.o
  LD [M]  /opt/zone/sdc1/bcache/src_bcache/drivers/md/bcache/bcache.ko
make[2]: Leaving directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
make[1]: Leaving directory `/usr/src/kernels/3.10.0-1127.el7.x86_64'
[root@AutoCloud src_bcache]#

发现编译成功了，让我们查看一下：

[root@AutoCloud src_bcache]# ls drivers/md/bcache/bcache.ko 
drivers/md/bcache/bcache.ko
[root@AutoCloud src_bcache]#

总结

至此，此篇文章结束，希望大家有所收获。
注意：低版本bcache有挺多bug，可能导致系统崩溃，使用时注意。