[PATCH 17/23] nfs: check mnt instead of superblock directly

Dave Hansen
2007-07-12T00:28:22Z

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.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---

lxc-dave/fs/nfs/dir.c | 3 ++-
lxc-dave/fs/nfsd/vfs.c | 4 ++--
2 files changed, 4 insertions(+), 3 deletions(-)

diff -puN fs/nfs/dir.c~nfs-check-mnt-instead-of-sb fs/nfs/dir.c
--- lxc/fs/nfs/dir.c~nfs-check-mnt-instead-of-sb 2007-07-10 12:46:13.000000000 -0700
+++ lxc-dave/fs/nfs/dir.c 2007-07-10 12:46:13.000000000 -0700
@@ -998,7 +998,8 @@ 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~nfs-check-mnt-instead-of-sb fs/nfsd/vfs.c
--- lxc/fs/nfsd/vfs.c~nfs-check-mnt-instead-of-sb 2007-07-10 12:46:13.000000000 -0700
+++ lxc-dave/fs/nfsd/vfs.c 2007-07-10 12:46:13.000000000 -0700
@@ -1810,7 +1810,7 @@ nfsd_permission(struct svc_export *exp,
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
@@ -1821,7 +1821,7 @@ nfsd_permission(struct svc_export *exp,
*/
if (!(acc & MAY_LOCAL_ACCESS))
if (acc & (MAY_WRITE | MAY_SATTR | MAY_TRUNC)) {
- if (EX_RDONLY(exp) || IS_RDONLY(inode))
+ if (EX_RDONLY(exp) || __mnt_is_readonly(exp->ex_mnt))
return nfserr_rofs;
if (/* (acc & MAY_WRITE) && */ IS_IMMUTABLE(inode))
return nfserr_perm;
_