Krister Johansen 706448f716 fuse: share lookup state between submount and its parent ... commit c4d361f66a upstream. Fuse submounts do not perform a lookup for the nodeid that they inherit from their parent. Instead, the code decrements the nlookup on the submount's fuse_inode when it is instantiated, and no forget is performed when a submount root is evicted. Trouble arises when the submount's parent is evicted despite the submount itself being in use. In this author's case, the submount was in a container and deatched from the initial mount namespace via a MNT_DEATCH operation. When memory pressure triggered the shrinker, the inode from the parent was evicted, which triggered enough forgets to render the submount's nodeid invalid. Since submounts should still function, even if their parent goes away, solve this problem by sharing refcounted state between the parent and its submount. When all of the references on this shared state reach zero, it's safe to forget the final lookup of the fuse nodeid. Signed-off-by: Krister Johansen <kjlx@templeofstupid.com> Cc: stable@vger.kernel.org Fixes: 1866d779d5 ("fuse: Allow fuse_fill_super_common() for submounts") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Krister Johansen <kjlx@templeofstupid.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-01-01 12:39:08 +00:00
..
acl.c	vfs: add rcu argument to ->get_acl() callback	2021-08-18 22:08:24 +02:00
control.c	fuse: Remove the control interface for virtio-fs	2022-07-21 16:06:19 +02:00
cuse.c	cuse: simplify refcount	2021-04-14 10:40:58 +02:00
dax.c	fuse: dax: set fc->dax to NULL in fuse_dax_conn_free()	2023-12-20 17:00:20 +01:00
dev.c	mm: multi-gen LRU: groundwork	2022-09-26 19:46:09 -07:00
dir.c	fuse: revalidate: don't invalidate if interrupted	2023-07-27 08:50:25 +02:00
file.c	attr: use consistent sgid stripping checks	2023-03-03 11:52:25 +01:00
fuse_i.h	fuse: share lookup state between submount and its parent	2024-01-01 12:39:08 +00:00
inode.c	fuse: share lookup state between submount and its parent	2024-01-01 12:39:08 +00:00
ioctl.c	fuse: ioctl: translate ENOSYS in outarg	2023-07-27 08:50:25 +02:00
Kconfig	dax: remove CONFIG_DAX_DRIVER	2021-12-04 08:58:51 -08:00
Makefile	fuse: move ioctl to separate source file	2021-04-12 15:04:30 +02:00
readdir.c	fuse: nlookup missing decrement in fuse_direntplus_link	2023-09-19 12:28:05 +02:00
virtio_fs.c	virtio_fs: Modify format for virtio_fs_direct_access	2022-07-26 10:38:58 +02:00
xattr.c	fuse: move fuse_invalidate_attr() into fuse_update_ctime()	2021-10-22 17:03:01 +02:00