Re: is there any prob in accessing new field added to inode mem structure, in some other functions?

From: Andreas Dilger
Date: Wed Dec 15 2004 - 16:31:29 EST


On Dec 15, 2004 11:41 -0500, Vineet Joglekar wrote:
> I am using linux 2.4.21 and I am trying to play with the etx2 file system. My aim is to allocate a data structure dynamically to every file that is opened, at the time of opening.
> What I tried to do was: added the structure pointer in the inode data structure "ext2_inode" say "x_ptr". In the function "ext2_read_inode" which reads the hard disk copy of inode into memory, I allocated memory to this pointer and filled the appropriate value. I chose this function as I thought when a file is opened, this function will be always called once. Upto this is working fine.
>
> Now when I try to use this pointer "x_ptr" in some other function, that is, "do_generic_file_read" - which is called while reading a file, I am not getting any value in that pointer, but a null. (which is supposed to be there as I am filling up appropriate value in function ext2_read_inode)

You are confusing "ext2_inode" (on disk structure, never change that) with
"ext2_inode_info" (in memory structure, what you want to change).

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://members.shaw.ca/adilger/ http://members.shaw.ca/golinux/

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