hugetlb: fix i_blocks accounting

For administrative purpose, we want to query actual block usage for
hugetlbfs file via fstat.  Currently, hugetlbfs always return 0.  Fix that
up since kernel already has all the information to track it properly.

Signed-off-by: Ken Chen <kenchen@google.com>
Acked-by: Adam Litke <agl@us.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index abe1e9f2a942..6121b57bbe96 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -801,6 +801,7 @@ retry:
 
                 if (vma->vm_flags & VM_SHARED) {
                         int err;
+                        struct inode *inode = mapping->host;
 
                         err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
                         if (err) {
@@ -809,6 +810,10 @@ retry:
                                         goto retry;
                                 goto out;
                         }
+
+                        spin_lock(&inode->i_lock);
+                        inode->i_blocks += BLOCKS_PER_HUGEPAGE;
+                        spin_unlock(&inode->i_lock);
                 } else
                         lock_page(page);
         }
@@ -1160,6 +1165,11 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to)
 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
 {
         long chg = region_truncate(&inode->i_mapping->private_list, offset);
+
+        spin_lock(&inode->i_lock);
+        inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
+        spin_unlock(&inode->i_lock);
+
         hugetlb_put_quota(inode->i_mapping, (chg - freed));
         hugetlb_acct_memory(-(chg - freed));
 }