Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse fixes from Miklos Szeredi:
 "A regression fix and bug fix bound for stable"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix fuse_write_end() if zero bytes were copied
  fuse: fix root dentry initialization

4 files changed, 14 insertions, 1 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 6a4d0e5418a1..b3ebe512d64c 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -286,6 +286,11 @@ const struct dentry_operations fuse_dentry_operations = {
 	.d_release	= fuse_dentry_release,
 };
 
+const struct dentry_operations fuse_root_dentry_operations = {
+	.d_init		= fuse_dentry_init,
+	.d_release	= fuse_dentry_release,
+};
+
 int fuse_valid_type(int m)
 {
 	return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index abc66a6237fd..2401c5dabb2a 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1985,6 +1985,10 @@ static int fuse_write_end(struct file *file, struct address_space *mapping,
 {
 	struct inode *inode = page->mapping->host;
 
+	/* Haven't copied anything?  Skip zeroing, size extending, dirtying. */
+	if (!copied)
+		goto unlock;
+
 	if (!PageUptodate(page)) {
 		/* Zero any unwritten bytes at the end of the page */
 		size_t endoff = (pos + copied) & ~PAGE_MASK;
@@ -1995,6 +1999,8 @@ static int fuse_write_end(struct file *file, struct address_space *mapping,
 
 	fuse_write_update_size(inode, pos + copied);
 	set_page_dirty(page);
+
+unlock:
 	unlock_page(page);
 	put_page(page);
 
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 0dfbb136e59a..91307940c8ac 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -692,6 +692,7 @@ static inline u64 get_node_id(struct inode *inode)
 extern const struct file_operations fuse_dev_operations;
 
 extern const struct dentry_operations fuse_dentry_operations;
+extern const struct dentry_operations fuse_root_dentry_operations;
 
 /**
  * Inode to nodeid comparison.
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 17141099f2e7..6fe6a88ecb4a 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1131,10 +1131,11 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 
 	err = -ENOMEM;
 	root = fuse_get_root_inode(sb, d.rootmode);
+	sb->s_d_op = &fuse_root_dentry_operations;
 	root_dentry = d_make_root(root);
 	if (!root_dentry)
 		goto err_dev_free;
-	/* only now - we want root dentry with NULL ->d_op */
+	/* Root dentry doesn't have .d_revalidate */
 	sb->s_d_op = &fuse_dentry_operations;
 
 	init_req = fuse_request_alloc(0);