root@geekos:/home/geekos# mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sde1 /dev/sdf1 mdadm: Note: this array has metadata at the start and may not be suitable as a boot device. If you plan to store '/boot' on this device please ensure that your boot-loader understands md/v1.x metadata, or use --metadata=0.90 Continue creating array?
时间: 2024-04-05 14:35:40 浏览: 169
这是 mdadm 工具的提示信息,它提醒您正在创建的 RAID 1 镜像可能不适合作为引导设备。这是因为该 RAID 1 镜像包含元数据(metadata)信息,并且这些元数据信息存储在磁盘的开头部分。如果您希望将 `/boot` 目录存储在该 RAID 1 镜像上,则需要确保您的引导加载程序(boot-loader)能够理解 md/v1.x 版本的元数据信息,否则可能会导致引导失败。
如果您不打算将 `/boot` 目录存储在该 RAID 1 镜像上,则可以忽略该提示信息,直接选择“yes”继续创建 RAID 1 镜像。如果您希望将 `/boot` 目录存储在该 RAID 1 镜像上,则需要确认您的引导加载程序能够支持 md/v1.x 版本的元数据,并且在创建 RAID 1 镜像时添加 `--metadata=0.90` 参数,以指定使用旧版本的元数据格式。
相关问题
root@geekos:/mnt/raid5# mdadm --detail /dev/md2 /dev/md2: Version : 1.2 Creation Time : Fri Jun 9 23:14:37 2023 Raid Level : raid5 Array Size : 207872 (203.03 MiB 212.86 MB) Used Dev Size : 103936 (101.52 MiB 106.43 MB) Raid Devices : 3 Total Devices : 3 Persistence : Superblock is persistent Update Time : Fri Jun 9 23:20:20 2023 State : clean Active Devices : 3 Working Devices : 3 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Name : geekos:2 (local to host geekos) UUID : ed5fb43d:5ad7732b:104eabee:f192ea39 Events : 34 Number Major Minor RaidDevice State 0 8 97 0 active sync /dev/sdg1 1 8 113 1 active sync /dev/sdh1 3 8 129 2 active sync /dev/sdi1计算合计物理空间以及可用空间
根据以上信息,该RAID5数组的总物理空间为203.03 MiB,即212.86 MB。由于RAID5需要至少三个磁盘才能组成,因此该数组的可用空间为2个磁盘的容量之和,即2 * 101.52 MiB = 203.04 MiB,即212.87 MB。请注意,这只是一个近似值,实际可用空间可能会因为文件系统和其他因素而略有不同。
# Makefile for GeekOS kernel, userspace, and tools # Copyright (c) 2004,2005 David H. Hovemeyer <[email protected]> # $Revision: 1.45 $ # This is free software. You are permitted to use, # redistribute, and modify it as specified in the file "COPYING". # Required software to build GeekOS: # - GNU Make (http://www.gnu.org/software/make) # - gcc 2.95.2 generating code for target (i386/ELF) and host platforms # - nasm (http://nasm.sourceforge.net) # - Perl5, AWK (any version), egrep # # Cygwin (http://cygwin.com) may be used to build GeekOS. # Make sure that gcc, binutils, nasm, and perl are installed. # NOTES: # - This makefile has been written carefully to work correctly # with the -j (parallel make) option. I regularly use "make -j 2" # to speed the build process on 2 processor systems. PROJECT_ROOT := .. VPATH := $(PROJECT_ROOT)/src # Figure out if we're compiling with cygwin, http://cygwin.com SYSTEM_NAME := $(shell uname -s) ifeq ($(findstring CYGWIN,$(SYSTEM_NAME)),CYGWIN) SYM_PFX := _ EXTRA_C_OPTS := -DNEED_UNDERSCORE -DGNU_WIN32 EXTRA_NASM_OPTS := -DNEED_UNDERSCORE NON_ELF_SYSTEM := yes EXTRA_CC_USER_OPTS := -Dmain=geekos_main endif # ---------------------------------------------------------------------- # Configuration - # Various options specifying how GeekOS should be built, # what source files to build, which user programs to build, # etc. This is generally the only section of the makefile # that will need to be modified. # ---------------------------------------------------------------------- # List of targets to build by default. # These targets encompass everything needed to boot # and run GeekOS. ALL_TARGETS := fd.img # Kernel source files KERNEL_C_SRCS := idt.c int.c trap.c irq.c io.c \ keyboard.c screen.c timer.c \ mem.c crc32.c \ gdt.c tss.c segment.c \ bget.c malloc.c \ synch.c kthread.c \ main.c # Kernel object files built from C source files KERNEL_C_OBJS := $(KERNEL_C_SRCS:%.c=geekos/%.o) # Kernel assembly files KERNEL_ASM_SRCS := lowlevel.asm # Kernel object files build from assembler source files KERNEL_ASM_OBJS := \ $(KERNEL_ASM_SRCS:%.asm=geekos/%.o) # All kernel object files KERNEL_OBJS := $(KERNEL_C_OBJS) \ $(KERNEL_ASM_OBJS) # Common library source files. # This library is linked into both the kernel and user programs. # It provides string functions and generic printf()-style # formatted output. COMMON_C_SRCS := fmtout.c string.c memmove.c # Common library object files. COMMON_C_OBJS := $(COMMON_C_SRCS:%.c=common/%.o) # Base address of kernel KERNEL_BASE_ADDR := 0x00010000 # Kernel entry point function KERNEL_ENTRY = $(SYM_PFX)Main # ---------------------------------------------------------------------- # Tools - # This section defines programs that are used to build GeekOS. # ---------------------------------------------------------------------- # Uncomment if cross compiling #TARGET_CC_PREFIX := i386-elf- # Target C compiler. gcc 2.95.2 or later should work. TARGET_CC := $(TARGET_CC_PREFIX)gcc # Host C compiler. This is used to compile programs to execute on # the host platform, not the target (x86) platform. On x86/ELF # systems, such as Linux and FreeBSD, it can generally be the same # as the target C compiler. HOST_CC := gcc # Target linker. GNU ld is probably to only one that will work. TARGET_LD := $(TARGET_CC_PREFIX)ld # Target archiver TARGET_AR := $(TARGET_CC_PREFIX)ar # Target ranlib TARGET_RANLIB := $(TARGET_CC_PREFIX)ranlib # Target nm TARGET_NM := $(TARGET_CC_PREFIX)nm # Target objcopy TARGET_OBJCOPY := $(TARGET_CC_PREFIX)objcopy # Nasm (http://nasm.sourceforge.net) NASM := nasm # Tool to build PFAT filesystem images. BUILDFAT := tools/builtFat.exe # Perl5 or later PERL := perl # Pad a file so its size is a multiple of some unit (i.e., sector size) PAD := $(PERL) $(PROJECT_ROOT)/scripts/pad # Create a file filled with zeroes. ZEROFILE := $(PERL) $(PROJECT_ROOT)/scripts/zerofile # Calculate size of file in sectors NUMSECS := $(PERL) $(PROJECT_ROOT)/scripts/numsecs # ---------------------------------------------------------------------- # Definitions - # Options passed to the tools. # ---------------------------------------------------------------------- # Flags used for all C source files GENERAL_OPTS := -O -Wall $(EXTRA_C_OPTS) CC_GENERAL_OPTS := $(GENERAL_OPTS) -Werror # Flags used for kernel C source files CC_KERNEL_OPTS := -g -DGEEKOS -I$(PROJECT_ROOT)/include # Flags user for kernel assembly files NASM_KERNEL_OPTS := -I$(PROJECT_ROOT)/src/geekos/ -f elf $(EXTRA_NASM_OPTS) # Flags used for common library and libc source files CC_USER_OPTS := -I$(PROJECT_ROOT)/include -I$(PROJECT_ROOT)/include/libc \ $(EXTRA_CC_USER_OPTS) # Flags passed to objcopy program (strip unnecessary sections from kernel.exe) OBJCOPY_FLAGS := -R .dynamic -R .note -R .comment # ---------------------------------------------------------------------- # Rules - # Describes how to compile the source files. # ---------------------------------------------------------------------- # Compilation of kernel C source files geekos/%.o : geekos/%.c $(TARGET_CC) -c $(CC_GENERAL_OPTS) $(CC_KERNEL_OPTS) $< -o geekos/$*.o # Compilation of kernel assembly source files geekos/%.o : geekos/%.asm $(NASM) $(NASM_KERNEL_OPTS) $< -o geekos/$*.o geekos/%.o : geekos/%.S $(TARGET_CC) -c $(CC_GENERAL_OPTS) $(CC_KERNEL_OPTS) $< -o geekos/$*.o # Compilation of common library C source files common/%.o : common/%.c $(TARGET_CC) -c $(CC_GENERAL_OPTS) $(CC_USER_OPTS) $< -o common/$*.o # ---------------------------------------------------------------------- # Targets - # Specifies files to be built # ---------------------------------------------------------------------- # Default target - see definition of ALL_TARGETS in Configuration section all : $(ALL_TARGETS) # Standard floppy image - just boots the kernel fd.img : geekos/fd_boot.bin geekos/setup.bin geekos/kernel.bin cat geekos/fd_boot.bin geekos/setup.bin geekos/kernel.bin > $@ # Floppy boot sector (first stage boot loader). geekos/fd_boot.bin : geekos/setup.bin geekos/kernel.bin $(PROJECT_ROOT)/src/geekos/fd_boot.asm $(NASM) -f bin \ -I$(PROJECT_ROOT)/src/geekos/ \ -DNUM_SETUP_SECTORS=`$(NUMSECS) geekos/setup.bin` \ -DNUM_KERN_SECTORS=`$(NUMSECS) geekos/kernel.bin` \ $(PROJECT_ROOT)/src/geekos/fd_boot.asm \ -o $@ # Setup program (second stage boot loader). geekos/setup.bin : geekos/kernel.exe $(PROJECT_ROOT)/src/geekos/setup.asm $(NASM) -f bin \ -I$(PROJECT_ROOT)/src/geekos/ \ -DENTRY_POINT=0x`egrep 'Main$$' geekos/kernel.syms |awk '{print $$1}'` \ $(PROJECT_ROOT)/src/geekos/setup.asm \ -o $@ $(PAD) $@ 512 # Loadable (flat) kernel image. geekos/kernel.bin : geekos/kernel.exe $(TARGET_OBJCOPY) $(OBJCOPY_FLAGS) -S -O binary geekos/kernel.exe geekos/kernel.bin $(PAD) $@ 512 # The kernel executable and symbol map. geekos/kernel.exe : $(KERNEL_OBJS) $(COMMON_C_OBJS) $(TARGET_LD) -o geekos/kernel.exe -Ttext $(KERNEL_BASE_ADDR) -e $(KERNEL_ENTRY) \ $(KERNEL_OBJS) $(COMMON_C_OBJS) $(TARGET_NM) geekos/kernel.exe > geekos/kernel.syms # Clean build directories of generated files clean : for d in geekos common libc user tools; do \ (cd $$d && rm -f *); \ done # Build header file dependencies, so source files are recompiled when # header files they depend on are modified. depend : $(GENERATED_LIBC_SRCS) $(TARGET_CC) -M $(CC_GENERAL_OPTS) $(CC_KERNEL_OPTS) \ $(KERNEL_C_SRCS:%.c=$(PROJECT_ROOT)/src/geekos/%.c) \ | $(PERL) -n -e 's,^(\S),geekos/$$1,;print' \ > depend.mak $(TARGET_CC) -M $(CC_GENERAL_OPTS) $(CC_USER_OPTS) \ $(COMMON_C_SRCS:%.c=$(PROJECT_ROOT)/src/common/%.c) \ | $(PERL) -n -e 's,^(\S),common/$$1,;print' \ >> depend.mak # By default, there are no header file dependencies. depend.mak : touch $@ include depend.mak 在哪里修改
### 解决方案
在编译 GeekOS 内核时出现的“variable ‘thread’ set but not used”错误,可以通过以下两种方式解决:修改源代码或调整 Makefile 中的编译器选项[^1]。
#### 修改源代码以消除警告
如果变量 `thread` 在函数中确实没有被使用,则可以采取以下方法之一来消除警告:
##### 方法 1:删除未使用的变量
如果变量 `thread` 不再需要,可以直接从代码中移除其定义和赋值操作。例如:
```c
// 原始代码
struct Kernel_Thread *thread;
thread = CreateKernelThread(...);
// 修改后的代码
// 删除未使用的变量 thread
```
##### 方法 2:显式声明变量未被使用
如果变量 `thread` 是为了调试或其他目的而存在,但当前不希望触发警告,可以通过 `(void)` 显式声明变量未被使用。例如:
```c
struct Kernel_Thread *thread;
thread = CreateKernelThread(...);
(void)thread; // 显式声明变量未被使用
```
##### 方法 3:确保变量被实际使用
如果变量 `thread` 的定义和赋值是逻辑上必需的,则应确保其在后续代码中被正确使用。例如:
```c
struct Kernel_Thread *thread;
thread = CreateKernelThread(...);
if (thread != NULL) {
// 对 thread 进行操作
}
```
#### 调整 Makefile 编译器选项
如果不想修改源代码,可以通过调整 `Makefile` 中的编译器选项来禁用该警告。具体方法如下:
##### 方法 1:禁用特定警告
可以在 `CFLAGS` 中添加 `-Wno-unused-but-set-variable` 以禁用该警告。例如:
```makefile
CFLAGS += -Wall -Werror -Wno-unused-but-set-variable
```
##### 方法 2:将警告降级为非错误
如果仍然希望保留警告信息但不将其视为错误,可以移除 `-Werror` 选项。例如:
```makefile
CFLAGS += -Wall
```
#### 示例代码与配置
以下是一个完整的示例,展示如何通过修改源代码或调整 Makefile 来解决该问题。
##### 源代码修改示例
```c
#include "geekos/thread.h"
void Main(void) {
struct Kernel_Thread *thread;
thread = CreateKernelThread(...);
(void)thread; // 显式声明变量未被使用
}
```
##### Makefile 配置示例
```makefile
CC = gcc
CFLAGS = -Wall -Werror -Wno-unused-but-set-variable
main: main.o
$(CC) $(CFLAGS) -o main main.o
main.o: main.c
$(CC) $(CFLAGS) -c main.c
```
### 注意事项
- 如果选择修改源代码,请确保不会破坏程序逻辑。
- 如果选择调整编译器选项,请注意可能会影响其他警告的检测[^2]。
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