嵌入式

yaffs2 文件系统在Linux上的移植问题

2019-07-12 16:09发布

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最近刚学嵌入式Linux这块儿，在参考朱兆琪 的 《嵌入式Linux手册》中的文件系统移植，书中写到



















下载好yaffs2之后打补丁，之后配置，在执行make uImage，可是没有出现书中所说的错误，在网上搜索一些资料，在Linux 2.6之后确实存在 yaffs2 在Linux 上的移植问题， 大概原因是 之后的Linux版本的 VFS发生了一些变化。但当我下载 亚飞yaffs2后，并给Linux打补丁，make uImage ,发现并没有问题，这是什么原因的？当我打开文件 ./Linux 3.6.7/fs/yaffs2/yaffs2_vfs.c 文件，发现了一个地方
/* * YAFFS: Yet Another Flash File System. A NAND-flash specific file system. * * Copyright (C) 2002-2011 Aleph One Ltd. * for Toby Churchill Ltd and Brightstar Engineering * * Created by Charles Manning * Acknowledgements: * Luc van OostenRyck for numerous patches. * Nick Bane for numerous patches. * Nick Bane for 2.5/2.6 integration. * Andras Toth for mknod rdev issue. * Michael Fischer for finding the problem with inode inconsistency. * Some code bodily lifted from JFFS * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ /* * * This is the file system front-end to YAFFS that hooks it up to * the VFS. * * Special notes: * >> 2.4: sb->u.generic_sbp points to the struct yaffs_dev associated with * this superblock * >> 2.6: sb->s_fs_info points to the struct yaffs_dev associated with this * superblock * >> inode->u.generic_ip points to the associated struct yaffs_obj. */ /* * There are two variants of the VFS glue code. This variant should compile * for any version of Linux. */ #include #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 10)) #define YAFFS_COMPILE_BACKGROUND #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 23)) #define YAFFS_COMPILE_FREEZER #endif #endif #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)) #define YAFFS_COMPILE_EXPORTFS #endif #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 35)) #define YAFFS_USE_SETATTR_COPY #define YAFFS_USE_TRUNCATE_SETSIZE #endif #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 35)) #define YAFFS_HAS_EVICT_INODE #endif #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 13)) #define YAFFS_NEW_FOLLOW_LINK 1 #else #define YAFFS_NEW_FOLLOW_LINK 0 #endif #if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 6, 0)) #define YAFFS_HAS_WRITE_SUPER #endif #if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 19)) #include #endif #include #include #include #include #include #include #if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)) #include #endif #include #include #include #include #include #if (YAFFS_NEW_FOLLOW_LINK == 1) #include #endif #ifdef YAFFS_COMPILE_EXPORTFS #include #endif #ifdef YAFFS_COMPILE_BACKGROUND #include #include #endif #ifdef YAFFS_COMPILE_FREEZER #include #endif #include #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0)) #include #define UnlockPage(p) unlock_page(p) #define Page_Uptodate(page) test_bit(PG_uptodate, &(page)->flags) /* FIXME: use sb->s_id instead ? */ #define yaffs_devname(sb, buf) bdevname(sb->s_bdev, buf) #else #include #define BDEVNAME_SIZE 0 #define yaffs_devname(sb, buf) kdevname(sb->s_dev) #if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)) /* added NCB 26/5/2006 for 2.4.25-vrs2-tcl1 kernel */ #define __user #endif #endif #if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)) #define YPROC_ROOT (&proc_root) #else #define YPROC_ROOT NULL #endif #if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)) #define Y_INIT_TIMER(a) init_timer(a) #else #define Y_INIT_TIMER(a) init_timer_on_stack(a) #endif #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 27)) #define YAFFS_USE_WRITE_BEGIN_END 1 #else #define YAFFS_USE_WRITE_BEGIN_END 0 #endif #if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 6, 0)) #define YAFFS_SUPER_HAS_DIRTY #endif #if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 2, 0)) #define set_nlink(inode, count) do { (inode)->i_nlink = (count); } while(0) #endif #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 28)) static uint32_t YCALCBLOCKS(uint64_t partition_size, uint32_t block_size) { uint64_t result = partition_size; do_div(result, block_size); return (uint32_t) result; } #else #define YCALCBLOCKS(s, b) ((s)/(b)) #endif
具体查看 该文件。
经过分析，最新的yaffs2是应该支持 linux 3.6.7 的，意即可以直接给Linux 3.6.7以上版本打补丁而不需修改，但是目前没有发现时候是其他地方的问题，如有发现分析错误的地方可以与我联系，一起分享。 好了，新手第一篇博客，我会更加努力改进学习~

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