移植YAFFS文件系统遇到问题解决问题

问题1：

fs/yaffs2/yaffs_vfs.c: In function 'yaffs_do_sync_fs':

fs/yaffs2/yaffs_vfs.c:2205:2: error: 'struct super_block' has no member named 's_dirt'
fs/yaffs2/yaffs_vfs.c:2216:8: error: 'struct super_block' has no member named 's_dirt'

fs/yaffs2/yaffs_vfs.c:2218:5: error: 'struct super_block' has no member named 's_dirt'

解决：在include/linux/fs.h文件中找到  struct super_block，在这个结构中加入变量s_dirt这个变量是额外加的，用来判断dirt or clean

问题2：

fs/yaffs2/yaffs_vfs.c:480:2: error: unknown field 'write_super' specified in initializer
fs/yaffs2/yaffs_vfs.c:480:2: warning: initialization from incompatible pointer type
解决：在include/linux/fs.h文件中找到struct super_operations 结构体，在其中加入write_super函数指针，

void (*write_super)(struct super_block *);

问题3：

fs/yaffs2/yaffs_vfs.c: In function 'yaffs_evict_inode':
fs/yaffs2/yaffs_vfs.c:875:2: error: implicit declaration of function 'end_writeback'

解决：出现这种错误一般是没有包含相应的头文件，所以搜索这个函数，发现在fs文件夹下的inode.c中，所以在include/linux/fs.h中声明这个函数

extern void end_writeback(struct inode *);

问题4：

fs/yaffs2/yaffs_vfs.c: In function 'yaffs_mtd_put_super':
fs/yaffs2/yaffs_vfs.c:2514:9: error: 'struct mtd_info' has no member named 'sync'
fs/yaffs2/yaffs_vfs.c:2515:6: error: 'struct mtd_info' has no member named 'sync'
fs/yaffs2/yaffs_vfs.c: In function 'yaffs_internal_read_super':
fs/yaffs2/yaffs_vfs.c:2702:2: error: 'struct mtd_info' has no member named 'erase'
fs/yaffs2/yaffs_vfs.c:2703:2: error: 'struct mtd_info' has no member named 'read'
fs/yaffs2/yaffs_vfs.c:2704:2: error: 'struct mtd_info' has no member named 'write'
fs/yaffs2/yaffs_vfs.c:2705:2: error: 'struct mtd_info' has no member named 'read_oob'
fs/yaffs2/yaffs_vfs.c:2706:2: error: 'struct mtd_info' has no member named 'write_oob'
fs/yaffs2/yaffs_vfs.c:2707:2: error: 'struct mtd_info' has no member named 'block_isbad'
fs/yaffs2/yaffs_vfs.c:2708:2: error: 'struct mtd_info' has no member named 'block_markbad'
fs/yaffs2/yaffs_vfs.c:2732:11: error: 'struct mtd_info' has no member named 'erase'
fs/yaffs2/yaffs_vfs.c:2733:11: error: 'struct mtd_info' has no member named 'block_isbad'
fs/yaffs2/yaffs_vfs.c:2734:11: error: 'struct mtd_info' has no member named 'block_markbad'
fs/yaffs2/yaffs_vfs.c:2734:34: error: 'struct mtd_info' has no member named 'read'
fs/yaffs2/yaffs_vfs.c:2734:48: error: 'struct mtd_info' has no member named 'write'
fs/yaffs2/yaffs_vfs.c:2736:11: error: 'struct mtd_info' has no member named 'read_oob'
fs/yaffs2/yaffs_vfs.c:2736:29: error: 'struct mtd_info' has no member named 'write_oob'
fs/yaffs2/yaffs_vfs.c:2757:11: error: 'struct mtd_info' has no member named 'erase'
fs/yaffs2/yaffs_vfs.c:2757:26: error: 'struct mtd_info' has no member named 'read'
fs/yaffs2/yaffs_vfs.c:2757:40: error: 'struct mtd_info' has no member named 'write'
fs/yaffs2/yaffs_vfs.c:2759:11: error: 'struct mtd_info' has no member named 'read_oob'
fs/yaffs2/yaffs_vfs.c:2759:29: error: 'struct mtd_info' has no member named 'write_oob'
解决：

搜索 struct mtd_info结构体，发现在include/linux/mtd/mtd.h中，有这个结构体的定义

struct mtd_info {
    u_char type;
    uint32_t flags;
    uint64_t size;     // Total size of the MTD

    ........................

  /*
     * Do not call via these pointers, use corresponding mtd_*()
     * wrappers instead.
     */
    int (*_erase) (struct mtd_info *mtd, struct erase_info *instr);
    int (*_point) (struct mtd_info *mtd, loff_t from, size_t len,
               size_t *retlen, void **virt, resource_size_t *phys);
    int (*_unpoint) (struct mtd_info *mtd, loff_t from, size_t len);
    unsigned long (*_get_unmapped_area) (struct mtd_info *mtd,
                         unsigned long len,
                         unsigned long offset,
                         unsigned long flags);
    int (*_read) (struct mtd_info *mtd, loff_t from, size_t len,
              size_t *retlen, u_char *buf);
    int (*_write) (struct mtd_info *mtd, loff_t to, size_t len,
               size_t *retlen, const u_char *buf);
    int (*_panic_write) (struct mtd_info *mtd, loff_t to, size_t len,
                 size_t *retlen, const u_char *buf);
    int (*_read_oob) (struct mtd_info *mtd, loff_t from,
              struct mtd_oob_ops *ops);

 ............................

}

发现这个结构体里的操作函数，都以_为开头，

/*
     * Do not call via these pointers, use corresponding mtd_*()
     * wrappers instead.
     */

不要通过指针调用这些函数，要用mtd_*()结构，，所以，这个问题就可以解决了，把出错部分都换为这里定义的就可以了

if (mtd->sync)
        mtd->sync(mtd);

修改为if (mtd->_sync)
        mtd_sync(mtd);

其他的类似，这里不一一列出了

问题5：

fs/yaffs2/yaffs_vfs.c: In function 'yaffs_internal_read_super':
fs/yaffs2/yaffs_vfs.c:2967:2: error: implicit declaration of function 'd_alloc_root'

解决：

在内核中搜索d_alloc_root这个函数，发现这个函数没有，有的只是在注释中，这个函数名被其他的取代了，被d_alloc_root函数取代了，所以把出错部分的函数名改过来就行