| Message ID | 20180529144612.16675-17-mszeredi@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, May 29, 2018 at 04:46:00PM +0200, Miklos Szeredi wrote: > From: Vivek Goyal <vgoyal@redhat.com> > > Metacopy dentry/inode is internal to overlay and is never exposed outside > of it. Exception is metacopy upper file used for fsync(). Modify d_real() > to look for dentries/inode which have data, but also allow matching upper > inode without data for the fsync case. > Hi Miklos, I am not able to see how in fsync() path d_real() gets called. If we decide to do fsync() on upper metacopy, then opening upper will not go through d_real(). And we never issue fsync() on lower. So I am scratching my head while trying to understand the d_real() and fsync() connection. Thanks Vivek > Signed-off-by: Vivek Goyal <vgoyal@redhat.com> > Reviewed-by: Amir Goldstein <amir73il@gmail.com> > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> > --- > fs/overlayfs/super.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index e0326a686f45..6687d547ec6b 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -101,10 +101,13 @@ static struct dentry *ovl_d_real(struct dentry *dentry, > } > > real = ovl_dentry_upper(dentry); > - if (real && (!inode || inode == d_inode(real))) > + if (real && (inode == d_inode(real))) > return real; > > - real = ovl_dentry_lower(dentry); > + if (real && !inode && ovl_has_upperdata(d_inode(dentry))) > + return real; > + > + real = ovl_dentry_lowerdata(dentry); > if (!real) > goto bug; > > -- > 2.14.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 31, 2018 at 12:05 AM, Vivek Goyal <vgoyal@redhat.com> wrote: > On Tue, May 29, 2018 at 04:46:00PM +0200, Miklos Szeredi wrote: >> From: Vivek Goyal <vgoyal@redhat.com> >> >> Metacopy dentry/inode is internal to overlay and is never exposed outside >> of it. Exception is metacopy upper file used for fsync(). Modify d_real() >> to look for dentries/inode which have data, but also allow matching upper >> inode without data for the fsync case. >> > > Hi Miklos, > > I am not able to see how in fsync() path d_real() gets called. If we > decide to do fsync() on upper metacopy, then opening upper will not > go through d_real(). And we never issue fsync() on lower. > > So I am scratching my head while trying to understand the d_real() and > fsync() connection. > fsync() exposes real meta inode to vfs, so file_dentry() needs to be able to find the real meta upper dentry. Thanks, Amir.
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index e0326a686f45..6687d547ec6b 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -101,10 +101,13 @@ static struct dentry *ovl_d_real(struct dentry *dentry, } real = ovl_dentry_upper(dentry); - if (real && (!inode || inode == d_inode(real))) + if (real && (inode == d_inode(real))) return real; - real = ovl_dentry_lower(dentry); + if (real && !inode && ovl_has_upperdata(d_inode(dentry))) + return real; + + real = ovl_dentry_lowerdata(dentry); if (!real) goto bug;