I downloaded sbull.c (for LDD 2nd Edition) from http://examples.oreilly.com/linuxdrive/. After compiling and inserting (registering as block device), I tried to mount different file systems (Although there is no valid file system there; my goal is to observe value of req->sector in sbull_transfer function). The observations are as follows:
File System req->sector
msdos 0
vfat 0
ext2 2
ext3 2
iso9000 72
I don't know about other file systems, but I believe the value of req->sector for msdos/vfat is wrong. Because when I mount a CF card having FAT file system on my Linux box (using USB mass storage driver), the first read request contains sector 0x20.
Does someone have any clue, why sbull gets this value as 0 rather then 0x20? Basically this means why CURRENT->sector is 0?
I am working on 2.4.18; a little old :(
Regards
Mohanlal
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