vfs: move ACL cache lookup into generic code

This moves logic for checking the cached ACL values from low-level
filesystems into generic code.  The end result is a streamlined ACL
check that doesn't need to load the inode->i_op->check_acl pointer at
all for the common cached case.

The filesystems also don't need to check for a non-blocking RCU walk
case in their acl_check() functions, because that is all handled at a
VFS layer.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 12 deletions

diff --git a/fs/generic_acl.c b/fs/generic_acl.c
index 70e90b4974ce..4949473d3542 100644
--- a/fs/generic_acl.c
+++ b/fs/generic_acl.c
@@ -192,18 +192,13 @@ generic_acl_chmod(struct inode *inode)
 int
 generic_check_acl(struct inode *inode, int mask)
 {
-        if (mask & MAY_NOT_BLOCK) {
-                if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
-                        return -ECHILD;
-        } else {
-                struct posix_acl *acl;
-
-                acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
-                if (acl) {
-                        int error = posix_acl_permission(inode, acl, mask);
-                        posix_acl_release(acl);
-                        return error;
-                }
+        struct posix_acl *acl;
+
+        acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
+        if (acl) {
+                int error = posix_acl_permission(inode, acl, mask);
+                posix_acl_release(acl);
+                return error;
         }
         return -EAGAIN;
 }