nilfs2: deny write access to inodes in snapshots
Snapshots of nilfs are read-only.
After super block instances (sb) will be unified, nilfs will need to
check write access by a way other than implicit test with
IS_RDONLY(inode). This is because IS_RDONLY() refers to MS_RDONLY bit
of inode->i_sb->s_flags and it will become inaccurate after the
unification of sb.
To prepare for the issue, this uses i_op->permission to deny write
access to inodes in snapshots.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index a65f465..185d160 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -588,6 +588,7 @@
.readlink = generic_readlink,
.follow_link = page_follow_link_light,
.put_link = page_put_link,
+ .permission = nilfs_permission,
};
const struct export_operations nilfs_export_ops = {