Re: [Ext2-devel] [PATCH] concurrent block allocation for ext2 against 2.5.64

[Matthew Wilcox]

On Thu, Mar 13, 2003 at 09:43:05PM +0300, Alex Tomas wrote:
> 
> fs/attr.c:
>         if (ia_valid & ATTR_SIZE) {
>                 if (attr->ia_size == inode->i_size) {
>                         if (ia_valid == ATTR_SIZE)
>                                 goto out;       /* we can skip lock_kernel() */
>                 } else {
>                         lock_kernel();
>                         error = vmtruncate(inode, attr->ia_size);
>                         unlock_kernel();
>                         if (error)
>                                 goto out;
>                 }
>         }
> 
> so, all (!) truncates are serialized

This looks like a bug.  It should be safe to delete them.  Rationale:

 - Documentation/filesystems/Locking says ->truncate is called without the BKL.
 - This isn't the only place vmtruncate() is called.  Several of the callers
   do it without the BKL (eg xfs, cifs).
 - vmtruncate() appears to handle its own locking (mapping->i_shared_sem)

Comments?

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