fuse: make fuse_permission() RCU aware
Only bail out of fuse_permission() on IPERM_FLAG_RCU when blocking is
actually necessary.
CC: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 8bd0ef9..3b84b91 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -970,6 +970,14 @@
return err;
}
+static int fuse_perm_getattr(struct inode *inode, int flags)
+{
+ if (flags & IPERM_FLAG_RCU)
+ return -ECHILD;
+
+ return fuse_do_getattr(inode, NULL, NULL);
+}
+
/*
* Check permission. The two basic access models of FUSE are:
*
@@ -989,9 +997,6 @@
bool refreshed = false;
int err = 0;
- if (flags & IPERM_FLAG_RCU)
- return -ECHILD;
-
if (!fuse_allow_task(fc, current))
return -EACCES;
@@ -1000,9 +1005,15 @@
*/
if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
- err = fuse_update_attributes(inode, NULL, NULL, &refreshed);
- if (err)
- return err;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ if (fi->i_time < get_jiffies_64()) {
+ refreshed = true;
+
+ err = fuse_perm_getattr(inode, flags);
+ if (err)
+ return err;
+ }
}
if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
@@ -1012,7 +1023,7 @@
attributes. This is also needed, because the root
node will at first have no permissions */
if (err == -EACCES && !refreshed) {
- err = fuse_do_getattr(inode, NULL, NULL);
+ err = fuse_perm_getattr(inode, flags);
if (!err)
err = generic_permission(inode, mask,
flags, NULL);
@@ -1023,13 +1034,16 @@
noticed immediately, only after the attribute
timeout has expired */
} else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
+ if (flags & IPERM_FLAG_RCU)
+ return -ECHILD;
+
err = fuse_access(inode, mask);
} else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
if (!(inode->i_mode & S_IXUGO)) {
if (refreshed)
return -EACCES;
- err = fuse_do_getattr(inode, NULL, NULL);
+ err = fuse_perm_getattr(inode, flags);
if (!err && !(inode->i_mode & S_IXUGO))
return -EACCES;
}