1 files changed, 17 insertions, 9 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 48ce82926d93..9187eee4128b 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -73,6 +73,8 @@ static struct vfsmount *shm_mnt;
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 
+#include "internal.h"
+
 #define BLOCKS_PER_PAGE  (PAGE_CACHE_SIZE/512)
 #define VM_ACCT(size)    (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
 
@@ -548,12 +550,12 @@ static int shmem_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	struct inode *inode = dentry->d_inode;
 	struct shmem_inode_info *info = SHMEM_I(inode);
 
-	spin_lock(&info->lock);
-	shmem_recalc_inode(inode);
-	spin_unlock(&info->lock);
-
+	if (info->alloced - info->swapped != inode->i_mapping->nrpages) {
+		spin_lock(&info->lock);
+		shmem_recalc_inode(inode);
+		spin_unlock(&info->lock);
+	}
 	generic_fillattr(inode, stat);
-
 	return 0;
 }
 
@@ -586,10 +588,16 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
 		}
 		if (newsize <= oldsize) {
 			loff_t holebegin = round_up(newsize, PAGE_SIZE);
-			unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);
-			shmem_truncate_range(inode, newsize, (loff_t)-1);
+			if (oldsize > holebegin)
+				unmap_mapping_range(inode->i_mapping,
+							holebegin, 0, 1);
+			if (info->alloced)
+				shmem_truncate_range(inode,
+							newsize, (loff_t)-1);
 			/* unmap again to remove racily COWed private pages */
-			unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);
+			if (oldsize > holebegin)
+				unmap_mapping_range(inode->i_mapping,
+							holebegin, 0, 1);
 		}
 	}
 
@@ -1023,7 +1031,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
 		 */
 		oldpage = newpage;
 	} else {
-		mem_cgroup_migrate(oldpage, newpage, true);
+		mem_cgroup_replace_page(oldpage, newpage);
 		lru_cache_add_anon(newpage);
 		*pagep = newpage;
 	}