Messages in this thread | | | Subject | Re: [Virtio-fs] [PATCH 3/4] fuse: Call vfs_get_tree() for submounts | From | Max Reitz <> | Date | Thu, 27 May 2021 15:24:40 +0200 |
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On 25.05.21 17:02, Greg Kurz wrote: > We recently fixed an infinite loop by setting the SB_BORN flag on > submounts along with the write barrier needed by super_cache_count(). > This is the job of vfs_get_tree() and FUSE shouldn't have to care > about the barrier at all. > > Split out some code from fuse_dentry_automount() to a new dedicated > fuse_get_tree_submount() handler for submounts and call vfs_get_tree(). > > The fs_private field of the filesystem context isn't used with > submounts : hijack it to pass the FUSE inode of the mount point > down to fuse_get_tree_submount().
What exactly do you mean by “isn’t used”? virtio_fs_init_fs_context() still sets it (it is non-NULL in fuse_dentry_automount() after fs_context_for_submount()). It does appear like it is never read, but one thing that definitely would need to be done is for it to be freed before putting mp_fi there.
So I think it may technically be fine to use this field, but then virtio_fs_init_fs_context() shouldn’t set it for submounts (should be discernible with fsc->purpose), and perhaps that should be a separate patch.
(Apart from that, this patch looks good to me, though.)
Max
> Finally, adapt virtiofs to use this. > > Signed-off-by: Greg Kurz <groug@kaod.org> > --- > fs/fuse/dir.c | 58 +++++++-------------------------------------- > fs/fuse/fuse_i.h | 6 +++++ > fs/fuse/inode.c | 44 ++++++++++++++++++++++++++++++++++ > fs/fuse/virtio_fs.c | 3 +++ > 4 files changed, 62 insertions(+), 49 deletions(-)
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