Add reference counting for devfs paths containing user created symbolic

links. The reference counting is needed to be able to determine if a
specific devfs path exists. For true device file paths we can traverse
the cdevp_list but a separate directory list is needed for user created
symbolic links.

Add a new directory entry flag DE_USER to mark entries which should
unreference their parent directory on deletion.

A new function to traverse cdevp_list and the directory list will be
introduced in a separate commit.

Idea from:	kib
Reviewed by:	kib

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c
index bbf0680..5f1063d 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -1564,6 +1564,7 @@ devfs_symlink(struct vop_symlink_args *ap)
 
 	dd = ap->a_dvp->v_data;
 	de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
+	de->de_flags = DE_USER;
 	de->de_uid = 0;
 	de->de_gid = 0;
 	de->de_mode = 0755;
@@ -1587,6 +1588,7 @@ devfs_symlink(struct vop_symlink_args *ap)
 	de_dotdot = TAILQ_FIRST(&dd->de_dlist);		/* "." */
 	de_dotdot = TAILQ_NEXT(de_dotdot, de_list);	/* ".." */
 	TAILQ_INSERT_AFTER(&dd->de_dlist, de_dotdot, de, de_list);
+	devfs_dir_ref_de(dmp, dd);
 
 	return (devfs_allocv(de, ap->a_dvp->v_mount, LK_EXCLUSIVE, ap->a_vpp));
 }