From: Dave Hansen If we depend on the inodes for writeability, we will not catch the r/o mounts when implemented. This patches uses __mnt_want_write(). It does not guarantee that the mount will stay writeable after the check. But, this is OK for one of the checks because it is just for a printk(). The other two are probably unnecessary and duplicate existing checks in the VFS. This won't make them better checks than before, but it will make them detect r/o mounts. Acked-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton --- fs/nfs/dir.c | 3 ++- fs/nfsd/vfs.c | 4 ++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff -puN fs/nfs/dir.c~r-o-bind-mounts-nfs-check-mnt-instead-of-superblock-directly fs/nfs/dir.c --- a/fs/nfs/dir.c~r-o-bind-mounts-nfs-check-mnt-instead-of-superblock-directly +++ a/fs/nfs/dir.c @@ -979,7 +979,8 @@ static int is_atomic_open(struct inode * if (nd->flags & LOOKUP_DIRECTORY) return 0; /* Are we trying to write to a read only partition? */ - if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) + if (__mnt_is_readonly(nd->mnt) && + (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) return 0; return 1; } diff -puN fs/nfsd/vfs.c~r-o-bind-mounts-nfs-check-mnt-instead-of-superblock-directly fs/nfsd/vfs.c --- a/fs/nfsd/vfs.c~r-o-bind-mounts-nfs-check-mnt-instead-of-superblock-directly +++ a/fs/nfsd/vfs.c @@ -1863,7 +1863,7 @@ nfsd_permission(struct svc_rqst *rqstp, inode->i_mode, IS_IMMUTABLE(inode)? " immut" : "", IS_APPEND(inode)? " append" : "", - IS_RDONLY(inode)? " ro" : ""); + __mnt_is_readonly(exp->ex_mnt)? " ro" : ""); dprintk(" owner %d/%d user %d/%d\n", inode->i_uid, inode->i_gid, current->fsuid, current->fsgid); #endif @@ -1874,7 +1874,7 @@ nfsd_permission(struct svc_rqst *rqstp, */ if (!(acc & MAY_LOCAL_ACCESS)) if (acc & (MAY_WRITE | MAY_SATTR | MAY_TRUNC)) { - if (exp_rdonly(rqstp, exp) || IS_RDONLY(inode)) + if (exp_rdonly(rqstp, exp) || __mnt_is_readonly(exp->ex_mnt)) return nfserr_rofs; if (/* (acc & MAY_WRITE) && */ IS_IMMUTABLE(inode)) return nfserr_perm; _