On Mon, Sep 15, 2008 at 10:11 PM, Rohit Sharma <imreckless@xxxxxxxxx> wrote: > I want to read ext2 superblock and display the structure. I assume you want to do it from userspace. ext2_fill_super() is called during mount time in kernel space. To read from userspace all you need is to open the device file and read a char buffer of 1024 at an offset of 1024 bytes and typecast it with ext2_super_block. You can get the definition of ext2_super_block from ext2_fs.h (You may already be having it in your /usr/include/ext2fs) and then you can print whatever fields you want. Alternatively you may also look at how debugfs does it (download source of e2fsprogs-1.41 from sourceforge.net) for detailed info. If you want to do in kernel space, the simplest option that i can think of is to traverse registered filesystems and then grab a copy of superblock and print it. > > which function do i need to call for that. > is it ext2_get_sb() or ext2_fill_super() or both ?? > > this is the function prototype: > static int ext2_fill_super(struct super_block *sb, void *data, int silent) > > what are the parameters data and silent used for. "data" is generally the char * to the parameters that you pass during mount which are parsed and appropriate flags are set in filesystem.. "silent" is more of debugging flag and prints some messages. Hope that helps Thanks - Manish > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
