On Wed, Feb 27, 2013 at 10:31:42PM +0100, Jilles Tjoelker wrote: > While testing recent changes to opendir(), I noticed that fstatfs() does > not return the MNT_UNION flag for a -t nullfs -o union mount. As a > result, opendir()/readdir() return files that exist in both top and > bottom directories twice (at least . and ..). Other -o union mounts and > -t unionfs mounts work correctly in this regard. > > The below patch passes through just the MNT_UNION flag of the nullfs > mount itself. Perhaps more flags should be passed through. > > commit fce32a779af4eb977c9b96feb6e4f811d89f2881 > Author: Jilles Tjoelker <jil...@stack.nl> > Date: Sat Feb 23 22:22:39 2013 +0100 > > nullfs: Preserve the MNT_UNION flag of the nullfs mount itself. > > This is needed so that opendir() can properly detect a union mount like > mount -t nullfs -o union dir1 dir2. > > diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c > index 3724e0a..ff06f57 100644 > --- a/sys/fs/nullfs/null_vfsops.c > +++ b/sys/fs/nullfs/null_vfsops.c > @@ -313,7 +313,7 @@ nullfs_statfs(mp, sbp) > > /* now copy across the "interesting" information and fake the rest */ > sbp->f_type = mstat.f_type; > - sbp->f_flags = mstat.f_flags; > + sbp->f_flags = (sbp->f_flags & MNT_UNION) | mstat.f_flags; > sbp->f_bsize = mstat.f_bsize; > sbp->f_iosize = mstat.f_iosize; > sbp->f_blocks = mstat.f_blocks;
Would it make sense to preserve more flags from the upper mount ? I see a use for MNT_NOEXEC as well, at least.
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