Re: [patch 20/21] fs: check for statfs overflow

[Nick Piggin <npiggin@suse.de>]

On Sun, Jun 08, 2008 at 12:06:45PM -0700, Andrew Morton wrote:
> On Wed, 04 Jun 2008 21:29:59 +1000 npiggin@suse.de wrote:
> 
> > Adds a check for an overflow in the filesystem size so if someone is
> > checking with statfs() on a 16G hugetlbfs in a 32bit binary that it
> > will report back EOVERFLOW instead of a size of 0.
> 
> -ENOUNDERSTAND.
> 
> Why won't a 16G filesystem work on a 32-bit binary?


Well it should work, but if it calls statfs then it will overflow the
f_bsize... ah, that should say 16G *block size* hugetlbfs. A 16G
hugetlbfs with 2M blocks should work just fine.



> 
> > Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
> > Signed-off-by: Jon Tollefson <kniht@linux.vnet.ibm.com>
> > Signed-off-by: Nick Piggin <npiggin@suse.de>
> > ---
> > 
> >  fs/compat.c |    4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > 
> > Index: linux-2.6/fs/compat.c
> > ===================================================================
> > --- linux-2.6.orig/fs/compat.c	2008-06-04 20:47:31.000000000 +1000
> > +++ linux-2.6/fs/compat.c	2008-06-04 20:51:28.000000000 +1000
> > @@ -197,8 +197,8 @@ static int put_compat_statfs(struct comp
> >  {
> >  	
> >  	if (sizeof ubuf->f_blocks == 4) {
> > -		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail) &
> > -		    0xffffffff00000000ULL)
> > +		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
> > +		     kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
> >  			return -EOVERFLOW;
> >  		/* f_files and f_ffree may be -1; it's okay
> >  		 * to stuff that into 32 bits */
> > @@ -271,8 +271,8 @@ out:
> >  static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf)
> >  {
> >  	if (sizeof ubuf->f_blocks == 4) {
> > -		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail) &
> > -		    0xffffffff00000000ULL)
> > +		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
> > +		     kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
> >  			return -EOVERFLOW;
> >  		/* f_files and f_ffree may be -1; it's okay
> >  		 * to stuff that into 32 bits */
> > Index: linux-2.6/fs/open.c
> > ===================================================================
> > --- linux-2.6.orig/fs/open.c	2008-06-04 20:47:31.000000000 +1000
> > +++ linux-2.6/fs/open.c	2008-06-04 20:51:28.000000000 +1000
> > @@ -63,7 +63,8 @@ static int vfs_statfs_native(struct dent
> >  		memcpy(buf, &st, sizeof(st));
> >  	else {
> >  		if (sizeof buf->f_blocks == 4) {
> > -			if ((st.f_blocks | st.f_bfree | st.f_bavail) &
> > +			if ((st.f_blocks | st.f_bfree | st.f_bavail |
> > +			     st.f_bsize | st.f_frsize) &
> >  			    0xffffffff00000000ULL)
> >  				return -EOVERFLOW;
> >  			/*
> > 
> > -- 

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