btrfs: provide simple rcu-walk ACL implementation
This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index cb518a4..6ae2c8c 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -187,18 +187,21 @@
int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags)
{
- struct posix_acl *acl;
int error = -EAGAIN;
- if (flags & IPERM_FLAG_RCU)
- return -ECHILD;
+ if (flags & IPERM_FLAG_RCU) {
+ if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+ error = -ECHILD;
- acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
- if (IS_ERR(acl))
- return PTR_ERR(acl);
- if (acl) {
- error = posix_acl_permission(inode, acl, mask);
- posix_acl_release(acl);
+ } else {
+ struct posix_acl *acl;
+ acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl) {
+ error = posix_acl_permission(inode, acl, mask);
+ posix_acl_release(acl);
+ }
}
return error;