fs/9p: Implement setting posix acl

This patch also update mode bits, as a normal file system.
I am not sure wether we should do that, considering that
a setxattr on the server will again update the ACL/mode value

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

3 files changed, 75 insertions, 2 deletions

diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index 4293b4599ff6..cad38bc1710e 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -17,9 +17,11 @@
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 #include <linux/slab.h>
+#include <linux/sched.h>
 #include <linux/posix_acl_xattr.h>
 #include "xattr.h"
 #include "acl.h"
+#include "v9fs_vfs.h"
 
 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
 {
@@ -119,7 +121,77 @@ static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
                               const void *value, size_t size,
                               int flags, int type)
 {
-        return 0;
+        int retval;
+        struct posix_acl *acl;
+        struct inode *inode = dentry->d_inode;
+
+        if (strcmp(name, "") != 0)
+                return -EINVAL;
+        if (S_ISLNK(inode->i_mode))
+                return -EOPNOTSUPP;
+        if (!is_owner_or_cap(inode))
+                return -EPERM;
+        if (value) {
+                /* update the cached acl value */
+                acl = posix_acl_from_xattr(value, size);
+                if (IS_ERR(acl))
+                        return PTR_ERR(acl);
+                else if (acl) {
+                        retval = posix_acl_valid(acl);
+                        if (retval)
+                                goto err_out;
+                }
+        } else
+                acl = NULL;
+
+        switch (type) {
+        case ACL_TYPE_ACCESS:
+                name = POSIX_ACL_XATTR_ACCESS;
+                if (acl) {
+                        mode_t mode = inode->i_mode;
+                        retval = posix_acl_equiv_mode(acl, &mode);
+                        if (retval < 0)
+                                goto err_out;
+                        else {
+                                struct iattr iattr;
+                                if (retval == 0) {
+                                        /*
+                                         * ACL can be represented
+                                         * by the mode bits. So don't
+                                         * update ACL.
+                                         */
+                                        acl = NULL;
+                                        value = NULL;
+                                        size = 0;
+                                }
+                                /* Updte the mode bits */
+                                iattr.ia_mode = ((mode & S_IALLUGO) |
+                                                 (inode->i_mode & ~S_IALLUGO));
+                                iattr.ia_valid = ATTR_MODE;
+                                /* FIXME should we update ctime ?
+                                 * What is the following setxattr update the
+                                 * mode ?
+                                 */
+                                v9fs_vfs_setattr_dotl(dentry, &iattr);
+                        }
+                }
+                break;
+        case ACL_TYPE_DEFAULT:
+                name = POSIX_ACL_XATTR_DEFAULT;
+                if (!S_ISDIR(inode->i_mode)) {
+                        retval = -EINVAL;
+                        goto err_out;
+                }
+                break;
+        default:
+                BUG();
+        }
+        retval = v9fs_xattr_set(dentry, name, value, size, flags);
+        if (!retval)
+                set_cached_acl(inode, type, acl);
+err_out:
+        posix_acl_release(acl);
+        return retval;
 }
 
 const struct xattr_handler v9fs_xattr_acl_access_handler = {
diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
index 88418c419ea7..09861295eef9 100644
--- a/fs/9p/v9fs_vfs.h
+++ b/fs/9p/v9fs_vfs.h
@@ -64,3 +64,4 @@ int v9fs_uflags2omode(int uflags, int extended);
 
 ssize_t v9fs_file_readn(struct file *, char *, char __user *, u32, u64);
 void v9fs_blank_wstat(struct p9_wstat *wstat);
+int v9fs_vfs_setattr_dotl(struct dentry *, struct iattr *);
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 1249b8323961..4b67bf1fb1d5 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1242,7 +1242,7 @@ static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
  *
  */
 
-static int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr)
+int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr)
 {
         int retval;
         struct v9fs_session_info *v9ses;