1 files changed, 31 insertions, 29 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 48ce82926d93..2afcdbbdb685 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);
 		}
 	}
 
@@ -835,14 +843,14 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
 		list_add_tail(&info->swaplist, &shmem_swaplist);
 
 	if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
-		swap_shmem_alloc(swap);
-		shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
-
 		spin_lock(&info->lock);
-		info->swapped++;
 		shmem_recalc_inode(inode);
+		info->swapped++;
 		spin_unlock(&info->lock);
 
+		swap_shmem_alloc(swap);
+		shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
+
 		mutex_unlock(&shmem_swaplist_mutex);
 		BUG_ON(page_mapped(page));
 		swap_writepage(page, wbc);
@@ -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;
 	}
@@ -1070,7 +1078,7 @@ repeat:
 	if (sgp != SGP_WRITE && sgp != SGP_FALLOC &&
 	    ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
 		error = -EINVAL;
-		goto failed;
+		goto unlock;
 	}
 
 	if (page && sgp == SGP_WRITE)
@@ -1238,11 +1246,15 @@ clear:
 	/* Perhaps the file has been truncated since we checked */
 	if (sgp != SGP_WRITE && sgp != SGP_FALLOC &&
 	    ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
+		if (alloced) {
+			ClearPageDirty(page);
+			delete_from_page_cache(page);
+			spin_lock(&info->lock);
+			shmem_recalc_inode(inode);
+			spin_unlock(&info->lock);
+		}
 		error = -EINVAL;
-		if (alloced)
-			goto trunc;
-		else
-			goto failed;
+		goto unlock;
 	}
 	*pagep = page;
 	return 0;
@@ -1250,23 +1262,13 @@ clear:
 	/*
 	 * Error recovery.
 	 */
-trunc:
-	info = SHMEM_I(inode);
-	ClearPageDirty(page);
-	delete_from_page_cache(page);
-	spin_lock(&info->lock);
-	info->alloced--;
-	inode->i_blocks -= BLOCKS_PER_PAGE;
-	spin_unlock(&info->lock);
 decused:
-	sbinfo = SHMEM_SB(inode->i_sb);
 	if (sbinfo->max_blocks)
 		percpu_counter_add(&sbinfo->used_blocks, -1);
 unacct:
 	shmem_unacct_blocks(info->flags, 1);
 failed:
-	if (swap.val && error != -EINVAL &&
-	    !shmem_confirm_swap(mapping, index, swap))
+	if (swap.val && !shmem_confirm_swap(mapping, index, swap))
 		error = -EEXIST;
 unlock:
 	if (page) {