UNIX Filesystems: Evolution, Design, and Implementation

Building the uxfs Filesystem

The source code for all of the files that are needed to build the uxfs filesystem for the 2.4.18 kernel is included at the end of the chapter. This includes the source for mkfs and fsdb, the kernel makefile, and the kernel source. The source tree downloaded from www.wiley.com/compbooks/spate is a gzipped tar archive. Download to any directory and issue the following commands:

# gunzip uxfs.tar.gz
# tar xvf uxfs.tar
# ls
uxfs.tar uxfs
# ls uxfs
cmds kern

Commands can be easily built. All that is required is for the uxfs.h header file to be located in the “../kern” directory. To build each of the commands, go to the cmds directory and issue the following:

# make fsdb
cc     fsdb.c     -o fsdb
# make fsdb
cc     fsdb.c     -o fsdb

The commands can then be used.

The kernel makefile is relatively straightforward as follows:

KERNELDIR = /usr/src/linux

include $(KERNELDIR)/.config

FLAGS = -D KERNEL  -DMODULE $(VERCFLAGS)
GLOBAL_CFLAGS = -g -I$(KERNELDIR)/include $(FLAGS)

M_OBJS = ux_dir.o ux_alloc.o ux_file.o ux_inode.o

M_TARGET = uxfs

SRCS = $(M_OBJS:.o=.c)

CFLAGS = $(GLOBAL_CFLAGS) $(EXTRA_CFLAGS)

$(M_TARGET) : $(M_OBJS)
    ld -r -o $@ $(M_OBJS)

$(M_OBJS) : %.o : %.c
    $(CC) -c $(CFLAGS) -o $@ $<

all: uxfs

clean:
    rm -f $(M_OBJS) $(M_TARGET)

To build the kernel source, the KERNELDIR variable at the top of the Makefile must be changed to reference the kernel source directory. Figure 14.3 shows how KERNELDIR is set to reference the 2.4.18 source tree.

Once this variable has ...