Re: Access content of file via inodes

["Kathy KN (HK)" <kathy.kn@gmail.com>]

On Apr 6, 2005 1:53 AM, Bryan Henderson <hbryan@us.ibm.com> wrote:
> >How do I access/read the content of the files via using inodes
> >or blocks that belong to the inode, at sys_link and vfs_link layer?
> 
> This is tricky because many interfaces that one would expect to use an
> inode as a file handle use a dentry instead.  To read the contents of a
> file via the VFS interface, you need a file pointer (struct file), and the
> file pointer identifies the file by dentry.  So you need to create a dummy
> dentry, which you can do with d_alloc_root(), and then create the file
> pointer with dentry_open(), then read the file with vfs_read().
> 
> That's for "via inodes."  I don't know what "via blocks" means.

Bryan,

Thanks for the description on how to read the contents of a file via
the VFS interface. I got to try to see if I can write it in codes, and make
sure that I can read the file via the vfs_read() routine. What I meant by
via blocks is to gain knowledge of the physical blocks used by the inodes
and retrieve the content from it directly, by accessing b_data.

Kathy