[fs/9P] Add posixacl mount option

The mount option access=client is overloaded as it assumes acl too.
Adding posixacl option to enable POSIX ACLs makes it explicit and clear.
Also it is convenient in the future to add other types of acls like richacls.

Ideally, the access mode 'client' should be just like V9FS_ACCESS_USER
except it underscores the location of access check.
Traditional 9P protocol lets the server perform access checks but with
this mode, all the access checks will be performed on the client itself.
Server just follows the client's directive.

Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index 0a2e480477a5..1ee3434239c8 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -59,7 +59,8 @@ int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
         struct v9fs_session_info *v9ses;
 
         v9ses = v9fs_inode2v9ses(inode);
-        if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
+        if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
+                        ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
                 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
                 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
                 return 0;
@@ -104,9 +105,10 @@ int v9fs_check_acl(struct inode *inode, int mask, unsigned int flags)
                 return -ECHILD;
 
         v9ses = v9fs_inode2v9ses(inode);
-        if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
+        if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
+                        ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
                 /*
-                 * On access = client mode get the acl
+                 * On access = client  and acl = on mode get the acl
                  * values from the server
                  */
                 return 0;