[PATCH] cifs: set backing_dev_info on new S_ISREG inodes

[PATCH] cifs: set backing_dev_info on new S_ISREG inodes

[Jeff Layton]

Testing on very recent kernel (2.6.36-rc6) made this warning pop:

    WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x65/0x70()
    Hardware name:
    Dirtiable inode bdi default != sb bdi cifs

...the following patch fixes it and seems to be the obviously correct
thing to do for cifs.

Cc: stable-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
Signed-off-by: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 fs/cifs/inode.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 2256124..d6db805 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -853,6 +853,8 @@ retry_iget5_locked:
 			inode->i_flags |= S_NOATIME | S_NOCMTIME;
 		if (inode->i_state & I_NEW) {
 			inode->i_ino = hash;
+			if (S_ISREG(inode->i_mode))
+				inode->i_data.backing_dev_info = sb->s_bdi;
 #ifdef CONFIG_CIFS_FSCACHE
 			/* initialize per-inode cache cookie pointer */
 			CIFS_I(inode)->fscache = NULL;
-- 
1.7.2.3

Re: [PATCH] cifs: set backing_dev_info on new S_ISREG inodes

[Christoph Hellwig]

On Wed, Sep 29, 2010 at 09:49:54AM -0400, Jeff Layton wrote:
> Testing on very recent kernel (2.6.36-rc6) made this warning pop:
> 
>     WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x65/0x70()
>     Hardware name:
>     Dirtiable inode bdi default != sb bdi cifs
> 
> ...the following patch fixes it and seems to be the obviously correct
> thing to do for cifs.

See my patch in the btrfs/default_backing_dev_info thread for the real
fix for the underlying issue.  But your patch won't harm either way.

Re: [PATCH] cifs: set backing_dev_info on new S_ISREG inodes

[Jeff Layton]

On Wed, 29 Sep 2010 19:17:30 -0400
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> wrote:

> On Wed, Sep 29, 2010 at 09:49:54AM -0400, Jeff Layton wrote:
> > Testing on very recent kernel (2.6.36-rc6) made this warning pop:
> > 
> >     WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x65/0x70()
> >     Hardware name:
> >     Dirtiable inode bdi default != sb bdi cifs
> > 
> > ...the following patch fixes it and seems to be the obviously correct
> > thing to do for cifs.
> 
> See my patch in the btrfs/default_backing_dev_info thread for the real
> fix for the underlying issue.  But your patch won't harm either way.
> 

Thanks Christoph. I looked to NFS as a model for this, which does a
very similar thing in nfs_fhget. It's probably reasonable for us to set
this here in case there is further churn in the VFS for this sort of
thing.

-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>