[PATCH] FUSE - mount options

This patch adds miscellaneous mount options to the FUSE filesystem.

The following mount options are added:

 o default_permissions:  check permissions with generic_permission()
 o allow_other:          allow other users to access files
 o allow_root:           allow root to access files
 o kernel_cache:         don't invalidate page cache on open

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 32 insertions, 3 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 8adc1eed164b..0950455914dd 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -418,7 +418,8 @@ static int fuse_revalidate(struct dentry *entry)
         struct fuse_conn *fc = get_fuse_conn(inode);
 
         if (get_node_id(inode) == FUSE_ROOT_ID) {
-                if (current->fsuid != fc->user_id)
+                if (!(fc->flags & FUSE_ALLOW_OTHER) &&
+                    current->fsuid != fc->user_id)
                         return -EACCES;
         } else if (time_before_eq(jiffies, fi->i_time))
                 return 0;
@@ -430,9 +431,31 @@ static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd)
 {
         struct fuse_conn *fc = get_fuse_conn(inode);
 
-        if (current->fsuid != fc->user_id)
+        if (!(fc->flags & FUSE_ALLOW_OTHER) && current->fsuid != fc->user_id)
                 return -EACCES;
-        else {
+        else if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
+                int err = generic_permission(inode, mask, NULL);
+
+                /* If permission is denied, try to refresh file
+                   attributes.  This is also needed, because the root
+                   node will at first have no permissions */
+                if (err == -EACCES) {
+                        err = fuse_do_getattr(inode);
+                        if (!err)
+                                err = generic_permission(inode, mask, NULL);
+                }
+
+                /* FIXME: Need some mechanism to revoke permissions:
+                   currently if the filesystem suddenly changes the
+                   file mode, we will not be informed about it, and
+                   continue to allow access to the file/directory.
+
+                   This is actually not so grave, since the user can
+                   simply keep access to the file/directory anyway by
+                   keeping it open... */
+
+                return err;
+        } else {
                 int mode = inode->i_mode;
                 if ((mask & MAY_WRITE) && IS_RDONLY(inode) &&
                     (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
@@ -636,6 +659,12 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
         int err;
         int is_truncate = 0;
 
+        if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
+                err = inode_change_ok(inode, attr);
+                if (err)
+                        return err;
+        }
+
         if (attr->ia_valid & ATTR_SIZE) {
                 unsigned long limit;
                 is_truncate = 1;