knfsd: nfsd4: make readonly access depend on pseudoflavor

Allow readonly access to vary depending on the pseudoflavor, using the flag
passed with each pseudoflavor in the export downcall.  The rest of the flags
are ignored for now, though some day we might also allow id squashing to vary
based on the flavor.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nfsd/nfsfh.c

@@ -255,7 +255,7 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 		goto out;
 
 	/* Finally, check access permissions. */
-	error = nfsd_permission(exp, dentry, access);
+	error = nfsd_permission(rqstp, exp, dentry, access);
 
 	if (error) {
 		dprintk("fh_verify: %s/%s permission failure, "

fs/nfsd/nfsproc.c

@@ -278,7 +278,8 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp,
 					 *   echo thing > device-special-file-or-pipe
 					 * by doing a CREATE with type==0
 					 */
-					nfserr = nfsd_permission(newfhp->fh_export,
+					nfserr = nfsd_permission(rqstp,
+								 newfhp->fh_export,
 								 newfhp->fh_dentry,
 								 MAY_WRITE|MAY_LOCAL_ACCESS);
 					if (nfserr && nfserr != nfserr_rofs)

fs/nfsd/vfs.c

@@ -328,7 +328,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 	/* The size case is special. It changes the file as well as the attributes.  */
 	if (iap->ia_valid & ATTR_SIZE) {
 		if (iap->ia_size < inode->i_size) {
-			err = nfsd_permission(fhp->fh_export, dentry, MAY_TRUNC|MAY_OWNER_OVERRIDE);
+			err = nfsd_permission(rqstp, fhp->fh_export, dentry, MAY_TRUNC|MAY_OWNER_OVERRIDE);
 			if (err)
 				goto out;
 		}
@@ -616,7 +616,7 @@ nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *suppor
 
 			sresult |= map->access;
 
-			err2 = nfsd_permission(export, dentry, map->how);
+			err2 = nfsd_permission(rqstp, export, dentry, map->how);
 			switch (err2) {
 			case nfs_ok:
 				result |= map->access;
@@ -1043,7 +1043,7 @@ nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	__be32		err;
 
 	if (file) {
-		err = nfsd_permission(fhp->fh_export, fhp->fh_dentry,
+		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
 				MAY_READ|MAY_OWNER_OVERRIDE);
 		if (err)
 			goto out;
@@ -1072,7 +1072,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	__be32			err = 0;
 
 	if (file) {
-		err = nfsd_permission(fhp->fh_export, fhp->fh_dentry,
+		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
 				MAY_WRITE|MAY_OWNER_OVERRIDE);
 		if (err)
 			goto out;
@@ -1801,7 +1801,8 @@ nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat)
  * Check for a user's access permissions to this inode.
  */
 __be32
-nfsd_permission(struct svc_export *exp, struct dentry *dentry, int acc)
+nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
+					struct dentry *dentry, int acc)
 {
 	struct inode	*inode = dentry->d_inode;
 	int		err;
@@ -1832,7 +1833,7 @@ nfsd_permission(struct svc_export *exp, struct dentry *dentry, int acc)
 	 */
 	if (!(acc & MAY_LOCAL_ACCESS))
 		if (acc & (MAY_WRITE | MAY_SATTR | MAY_TRUNC)) {
-			if (EX_RDONLY(exp) || IS_RDONLY(inode))
+			if (EX_RDONLY(exp, rqstp) || IS_RDONLY(inode))
 				return nfserr_rofs;
 			if (/* (acc & MAY_WRITE) && */ IS_IMMUTABLE(inode))
 				return nfserr_perm;

include/linux/nfsd/export.h

@@ -112,10 +112,21 @@ struct svc_expkey {
 
 #define EX_SECURE(exp)		(!((exp)->ex_flags & NFSEXP_INSECURE_PORT))
 #define EX_ISSYNC(exp)		(!((exp)->ex_flags & NFSEXP_ASYNC))
-#define EX_RDONLY(exp)		((exp)->ex_flags & NFSEXP_READONLY)
 #define EX_NOHIDE(exp)		((exp)->ex_flags & NFSEXP_NOHIDE)
 #define EX_WGATHER(exp)		((exp)->ex_flags & NFSEXP_GATHERED_WRITES)
 
+static inline int EX_RDONLY(struct svc_export *exp, struct svc_rqst *rqstp)
+{
+	struct exp_flavor_info *f;
+	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
+
+	for (f = exp->ex_flavors; f < end; f++) {
+		if (f->pseudoflavor == rqstp->rq_flavor)
+			return f->flags & NFSEXP_READONLY;
+	}
+	return exp->ex_flags & NFSEXP_READONLY;
+}
+
 __be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp);
 
 /*

include/linux/nfsd/nfsd.h

@@ -119,7 +119,8 @@ __be32		nfsd_statfs(struct svc_rqst *, struct svc_fh *,
 				struct kstatfs *);
 
 int		nfsd_notify_change(struct inode *, struct iattr *);
-__be32		nfsd_permission(struct svc_export *, struct dentry *, int);
+__be32		nfsd_permission(struct svc_rqst *, struct svc_export *,
+				struct dentry *, int);
 int		nfsd_sync_dir(struct dentry *dp);
 
 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)