[patch] fix hugetlbfs quota leak

["Ken Chen" <kenchen@google.com>]

In the error path of both shared and private hugetlb page allocation,
the file system quota is never undone, leading to fs quota leak.
Patch to fix them up.

Signed-off-by: Ken Chen <kenchen@google.com>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7224a4f..b2863f3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -420,6 +420,8 @@ static struct page *alloc_huge_page_private(struct
vm_area_struct *vma,
 	spin_unlock(&hugetlb_lock);
 	if (!page)
 		page = alloc_buddy_huge_page(vma, addr);
+	if (!page)
+		hugetlb_put_quota(vma->vm_file->f_mapping, 1);
 	return page ? page : ERR_PTR(-VM_FAULT_OOM);
 }

@@ -1206,8 +1208,10 @@ int hugetlb_reserve_pages(struct inode *inode,
long from, long to)
 	if (hugetlb_get_quota(inode->i_mapping, chg))
 		return -ENOSPC;
 	ret = hugetlb_acct_memory(chg);
-	if (ret < 0)
+	if (ret < 0) {
+		hugetlb_put_quota(inode->i_mapping, chg);
 		return ret;
+	}
 	region_add(&inode->i_mapping->private_list, from, to);
 	return 0;
 }

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