lkml.org 
[lkml]   [2009]   [Mar]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 4/8 ver5] exofs: address_space_operations
On Tue, 31 Mar 2009 12:04:36 +0300 Boaz Harrosh <bharrosh@panasas.com> wrote:

> >> +static int write_exec(struct page_collect *pcol)
> >> +{
> >> + struct exofs_i_info *oi = exofs_i(pcol->inode);
> >> + struct osd_obj_id obj = {pcol->sbi->s_pid,
> >> + pcol->inode->i_ino + EXOFS_OBJ_OFF};
> >> + struct osd_request *or = NULL;
> >> + struct page_collect *pcol_copy = NULL;
> >> + loff_t i_start = pcol->pg_first << PAGE_CACHE_SHIFT;
> >
> > bug. On 32-bit this shift will overflow prior to getting promoted to
> > 64-bit. Do:
> >
> > loff_t i_start = (loff_t)pcol->pg_first << PAGE_CACHE_SHIFT;
> >
>
> In that case I might make pcol->pg_first loff_t.

That would work.

> Why is inode->i_index not an loff_t then?

hm, what's i_index?

> Page-index <=> byte-offset, is done all the time 12 bits does not
> make a difference.

Page indices are 32-bit on 32-bit CPUs. File offsets are 64-bit. We
are careful to avoid the above overflow bug whenever the conversion
from page index to file size is made. Try

fgrep '(loff_t)' mm/*.c



\
 
 \ /
  Last update: 2009-03-31 12:25    [from the cache]
©2003-2011 Jasper Spaans