[PATCH] fs: make block fiemap mapping length at least blocksize long

[PATCH] fs: make block fiemap mapping length at least blocksize long

[Josef Bacik]

Some filesystems don't deal well with being asked to map less than blocksize
blocks (GFS2 for example).  Since we are always mapping at least blocksize
sections anyway, just make sure len is at least as big as a blocksize so we
don't trip up any filesystems.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
---
 fs/ioctl.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index d6cc164..6b53c24 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -273,6 +273,13 @@ int __generic_block_fiemap(struct inode *inode,
 		len = isize;
 	}
 
+	/*
+	 * Some filesystems can't deal with being asked to map less than
+	 * blocksize, so make sure our len is at least block length.
+	 */
+	if (logical_to_blk(inode, len) == 0)
+		len = blk_to_logical(inode, 1);
+
 	start_blk = logical_to_blk(inode, start);
 	last_blk = logical_to_blk(inode, start + len - 1);
 
-- 
1.6.6.1

Re: [PATCH] fs: make block fiemap mapping length at least blocksize long

[Steven Whitehouse]

Hi,

Is there any reason this cannot be sent to Linus now?

Steve.

On Wed, 2010-12-08 at 12:03 -0500, Josef Bacik wrote:
> Some filesystems don't deal well with being asked to map less than blocksize
> blocks (GFS2 for example).  Since we are always mapping at least blocksize
> sections anyway, just make sure len is at least as big as a blocksize so we
> don't trip up any filesystems.  Thanks,
> 
> Signed-off-by: Josef Bacik <josef@redhat.com>
> ---
>  fs/ioctl.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/ioctl.c b/fs/ioctl.c
> index d6cc164..6b53c24 100644
> --- a/fs/ioctl.c
> +++ b/fs/ioctl.c
> @@ -273,6 +273,13 @@ int __generic_block_fiemap(struct inode *inode,
>  		len = isize;
>  	}
>  
> +	/*
> +	 * Some filesystems can't deal with being asked to map less than
> +	 * blocksize, so make sure our len is at least block length.
> +	 */
> +	if (logical_to_blk(inode, len) == 0)
> +		len = blk_to_logical(inode, 1);
> +
>  	start_blk = logical_to_blk(inode, start);
>  	last_blk = logical_to_blk(inode, start + len - 1);
>  

Re: [PATCH] fs: make block fiemap mapping length at least blocksize long

[Andrew Morton]

On Tue, 01 Feb 2011 11:46:50 +0000
Steven Whitehouse <swhiteho@redhat.com> wrote:

> On Wed, 2010-12-08 at 12:03 -0500, Josef Bacik wrote:
> > Some filesystems don't deal well with being asked to map less than blocksize
> > blocks (GFS2 for example).  Since we are always mapping at least blocksize
> > sections anyway, just make sure len is at least as big as a blocksize so we
> > don't trip up any filesystems.  Thanks,
> > 
> > Signed-off-by: Josef Bacik <josef@redhat.com>
> > ---
> >  fs/ioctl.c |    7 +++++++
> >  1 files changed, 7 insertions(+), 0 deletions(-)
> > 
> > diff --git a/fs/ioctl.c b/fs/ioctl.c
> > index d6cc164..6b53c24 100644
> > --- a/fs/ioctl.c
> > +++ b/fs/ioctl.c
> > @@ -273,6 +273,13 @@ int __generic_block_fiemap(struct inode *inode,
> >  		len = isize;
> >  	}
> >  
> > +	/*
> > +	 * Some filesystems can't deal with being asked to map less than
> > +	 * blocksize, so make sure our len is at least block length.
> > +	 */
> > +	if (logical_to_blk(inode, len) == 0)
> > +		len = blk_to_logical(inode, 1);
> > +
> >  	start_blk = logical_to_blk(inode, start);
> >  	last_blk = logical_to_blk(inode, start + len - 1);
> >  

(top-posting repaired)

> Hi,
> 
> Is there any reason this cannot be sent to Linus now?
> 

I sent it to viro a couple of weeks back and it was ignored.  I don't
know why this happens :(