From dd70bf7cf99a7d583bf1525780eeda60ea4f7b97 Mon Sep 17 00:00:00 2001 From: Erez Zadok Date: Tue, 22 Sep 2009 17:34:46 -0400 Subject: [PATCH] Unionfs: fix readonly nfs2/3 permission handling In unionfs_permission: NFSv2/3 return EACCES on readonly-exported, locally readonly-mounted file systems, instead of EROFS like other file systems do. So we have no choice here but to intercept this and ignore it for NFS branches marked readonly. Specifically, we avoid using NFS's own "broken" ->permission method, and rely on generic_permission() to do basic checking for us. Signed-off-by: Erez Zadok --- fs/unionfs/inode.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c index 297f33a385e..946846f689c 100644 --- a/fs/unionfs/inode.c +++ b/fs/unionfs/inode.c @@ -845,6 +845,20 @@ static int unionfs_permission(struct inode *inode, int mask, err = 0; } + /* + * NFS HACK: NFSv2/3 return EACCES on readonly-exported, + * locally readonly-mounted file systems, instead of EROFS + * like other file systems do. So we have no choice here + * but to intercept this and ignore it for NFS branches + * marked readonly. Specifically, we avoid using NFS's own + * "broken" ->permission method, and rely on + * generic_permission() to do basic checking for us. + */ + if (err && err == -EACCES && + is_robranch_super(inode->i_sb, bindex) && + lower_inode->i_sb->s_magic == NFS_SUPER_MAGIC) + err = generic_permission(lower_inode, mask, NULL); + /* * The permissions are an intersection of the overall directory * permissions, so we fail if one fails. -- 2.43.0