1 files changed, 61 insertions, 50 deletions

diff --git a/kernel/mm/shmem.c b/kernel/mm/shmem.c
index 47d536e59..ea5a70cfc 100644
--- a/kernel/mm/shmem.c
+++ b/kernel/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)
 
@@ -542,6 +544,21 @@ void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
 }
 EXPORT_SYMBOL_GPL(shmem_truncate_range);
 
+static int shmem_getattr(struct vfsmount *mnt, struct dentry *dentry,
+			 struct kstat *stat)
+{
+	struct inode *inode = dentry->d_inode;
+	struct shmem_inode_info *info = SHMEM_I(inode);
+
+	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;
+}
+
 static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
@@ -569,12 +586,18 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
 			i_size_write(inode, newsize);
 			inode->i_ctime = inode->i_mtime = CURRENT_TIME;
 		}
-		if (newsize < oldsize) {
+		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);
 		}
 	}
 
@@ -597,8 +620,7 @@ static void shmem_evict_inode(struct inode *inode)
 			list_del_init(&info->swaplist);
 			mutex_unlock(&shmem_swaplist_mutex);
 		}
-	} else
-		kfree(info->symlink);
+	}
 
 	simple_xattrs_free(&info->xattrs);
 	WARN_ON(inode->i_blocks);
@@ -820,14 +842,14 @@ 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);
@@ -1008,7 +1030,7 @@ 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;
 	}
@@ -1055,7 +1077,7 @@ 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)
@@ -1223,11 +1245,15 @@ 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;
@@ -1235,23 +1261,13 @@ 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) {
@@ -2445,8 +2461,8 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
 	info = SHMEM_I(inode);
 	inode->i_size = len-1;
 	if (len <= SHORT_SYMLINK_LEN) {
-		info->symlink = kmemdup(symname, len, GFP_KERNEL);
-		if (!info->symlink) {
+		inode->i_link = kmemdup(symname, len, GFP_KERNEL);
+		if (!inode->i_link) {
 			iput(inode);
 			return -ENOMEM;
 		}
@@ -2474,30 +2490,23 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
 	return 0;
 }
 
-static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd)
-{
-	nd_set_link(nd, SHMEM_I(d_inode(dentry))->symlink);
-	return NULL;
-}
-
-static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
+static const char *shmem_follow_link(struct dentry *dentry, void **cookie)
 {
 	struct page *page = NULL;
 	int error = shmem_getpage(d_inode(dentry), 0, &page, SGP_READ, NULL);
-	nd_set_link(nd, error ? ERR_PTR(error) : kmap(page));
-	if (page)
-		unlock_page(page);
-	return page;
+	if (error)
+		return ERR_PTR(error);
+	unlock_page(page);
+	*cookie = page;
+	return kmap(page);
 }
 
-static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
+static void shmem_put_link(struct inode *unused, void *cookie)
 {
-	if (!IS_ERR(nd_get_link(nd))) {
-		struct page *page = cookie;
-		kunmap(page);
-		mark_page_accessed(page);
-		page_cache_release(page);
-	}
+	struct page *page = cookie;
+	kunmap(page);
+	mark_page_accessed(page);
+	page_cache_release(page);
 }
 
 #ifdef CONFIG_TMPFS_XATTR
@@ -2642,7 +2651,7 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
 
 static const struct inode_operations shmem_short_symlink_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= shmem_follow_short_symlink,
+	.follow_link	= simple_follow_link,
 #ifdef CONFIG_TMPFS_XATTR
 	.setxattr	= shmem_setxattr,
 	.getxattr	= shmem_getxattr,
@@ -3072,6 +3081,7 @@ static struct inode *shmem_alloc_inode(struct super_block *sb)
 static void shmem_destroy_callback(struct rcu_head *head)
 {
 	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kfree(inode->i_link);
 	kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
 }
 
@@ -3128,6 +3138,7 @@ static const struct file_operations shmem_file_operations = {
 };
 
 static const struct inode_operations shmem_inode_operations = {
+	.getattr	= shmem_getattr,
 	.setattr	= shmem_setattr,
 #ifdef CONFIG_TMPFS_XATTR
 	.setxattr	= shmem_setxattr,
@@ -3369,8 +3380,8 @@ put_path:
  * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be
  * 	kernel internal.  There will be NO LSM permission checks against the
  * 	underlying inode.  So users of this interface must do LSM checks at a
- * 	higher layer.  The one user is the big_key implementation.  LSM checks
- * 	are provided at the key level rather than the inode level.
+ *	higher layer.  The users are the big_key and shm implementations.  LSM
+ *	checks are provided at the key or shm level rather than the inode.
  * @name: name for dentry (to be seen in /proc/<pid>/maps
  * @size: size to be set for the file
  * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size