About VFS locking strategy...

[Kris Kennaway]

On Thu, Jan 19, 2006 at 08:43:55AM +0900, Shin,Hee-Sub wrote:
> Hi all. 
> 
>  
> 
> I'm speluking with source code of FreeBSD now, comparing VFS of FBSD and
> the linux's. 
> 
>  
> 
> I have a question related with concurrent accesses to the file system. It
> is seemed that VFS locks and unlocks each VNODEs before calling VNODE OPS
> provided by underlying FS. For example, it calls vn_lock(vp, ...) before
> jumps to VOP_READ() in vn_read(). 
> 
>  
> 
> WindowsCE kernel also has a component that is responsible for switching FS
> requests to appropriate file-system underlying and similar with VFS of many
> UNIX variants, but it's not perfectly same. In WindowsCE world, file system
> driver code can be called on re-entry and file system programmer should
> keep this in mind. The manager does not manage any synchronization problems
> that can be occurred when multiple threads access to the file system. It
> has only a few locks for protecting its own data structures. 
> 
>  
> 
> How does it manage synchronization problems in the VFS of FreeBSD? 
> 
>  
> 
> Please give me a detailed description about lock strategy the FreeBSD uses. 

This question might be too general to get any replies, but it would
still be better asked on fs@ or hackers at .

Kris
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-questions/attachments/20060118/87b2ac75/attachment.bin