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

Pull fuse update from Miklos Szeredi:
"This contains a fix for a potential use-after-module-unload bug
noticed by Al and caching improvements for read-only fuse filesystems
by Andrew Gallagher"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: support clients that don't implement 'open'
fuse: don't invalidate attrs when not using atime
fuse: fix SetPageUptodate() condition in STORE
fuse: fix pipe_buf_operations

fs/fuse/dev.c

···
 	return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
 }
 
-static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
-				   struct pipe_buffer *buf)
-{
-	return 1;
-}
-
-static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
-	.can_merge = 0,
-	.map = generic_pipe_buf_map,
-	.unmap = generic_pipe_buf_unmap,
-	.confirm = generic_pipe_buf_confirm,
-	.release = generic_pipe_buf_release,
-	.steal = fuse_dev_pipe_buf_steal,
-	.get = generic_pipe_buf_get,
-};
-
 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 				    struct pipe_inode_info *pipe,
 				    size_t len, unsigned int flags)
···
 		buf->page = bufs[page_nr].page;
 		buf->offset = bufs[page_nr].offset;
 		buf->len = bufs[page_nr].len;
-		buf->ops = &fuse_dev_pipe_buf_ops;
+		/*
+		 * Need to be careful about this.  Having buf->ops in module
+		 * code can Oops if the buffer persists after module unload.
+		 */
+		buf->ops = &nosteal_pipe_buf_ops;
 
 		pipe->nrbufs++;
 		page_nr++;
···
 
 		this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
 		err = fuse_copy_page(cs, &page, offset, this_num, 0);
-		if (!err && offset == 0 && (num != 0 || file_size == end))
+		if (!err && offset == 0 &&
+		    (this_num == PAGE_CACHE_SIZE || file_size == end))
 			SetPageUptodate(page);
 		unlock_page(page);
 		page_cache_release(page);

fs/fuse/dir.c

···
 	get_fuse_inode(inode)->i_time = 0;
 }
 
+/**
+ * Mark the attributes as stale due to an atime change.  Avoid the invalidate if
+ * atime is not used.
+ */
+void fuse_invalidate_atime(struct inode *inode)
+{
+	if (!IS_RDONLY(inode))
+		fuse_invalidate_attr(inode);
+}
+
 /*
  * Just mark the entry as stale, so that a next attempt to look it up
  * will result in a new lookup call to userspace
···
 	}
 
 	__free_page(page);
-	fuse_invalidate_attr(inode); /* atime changed */
+	fuse_invalidate_atime(inode);
 	return err;
 }
 
···
 		link[req->out.args[0].size] = '\0';
  out:
 	fuse_put_request(fc, req);
-	fuse_invalidate_attr(inode); /* atime changed */
+	fuse_invalidate_atime(inode);
 	return link;
 }
 

fs/fuse/file.c

···
 	if (atomic_dec_and_test(&ff->count)) {
 		struct fuse_req *req = ff->reserved_req;
 
-		if (sync) {
+		if (ff->fc->no_open) {
+			/*
+			 * Drop the release request when client does not
+			 * implement 'open'
+			 */
+			req->background = 0;
+			path_put(&req->misc.release.path);
+			fuse_put_request(ff->fc, req);
+		} else if (sync) {
 			req->background = 0;
 			fuse_request_send(ff->fc, req);
 			path_put(&req->misc.release.path);
···
 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 		 bool isdir)
 {
-	struct fuse_open_out outarg;
 	struct fuse_file *ff;
-	int err;
 	int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
 
 	ff = fuse_file_alloc(fc);
 	if (!ff)
 		return -ENOMEM;
 
-	err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
-	if (err) {
-		fuse_file_free(ff);
-		return err;
+	ff->fh = 0;
+	ff->open_flags = FOPEN_KEEP_CACHE; /* Default for no-open */
+	if (!fc->no_open || isdir) {
+		struct fuse_open_out outarg;
+		int err;
+
+		err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
+		if (!err) {
+			ff->fh = outarg.fh;
+			ff->open_flags = outarg.open_flags;
+
+		} else if (err != -ENOSYS || isdir) {
+			fuse_file_free(ff);
+			return err;
+		} else {
+			fc->no_open = 1;
+		}
 	}
 
 	if (isdir)
-		outarg.open_flags &= ~FOPEN_DIRECT_IO;
+		ff->open_flags &= ~FOPEN_DIRECT_IO;
 
-	ff->fh = outarg.fh;
 	ff->nodeid = nodeid;
-	ff->open_flags = outarg.open_flags;
 	file->private_data = fuse_file_get(ff);
 
 	return 0;
···
 		SetPageUptodate(page);
 	}
 
-	fuse_invalidate_attr(inode); /* atime changed */
+	fuse_invalidate_atime(inode);
  out:
 	unlock_page(page);
 	return err;
···
 			fuse_read_update_size(inode, pos,
 					      req->misc.read.attr_ver);
 		}
-		fuse_invalidate_attr(inode); /* atime changed */
+		fuse_invalidate_atime(inode);
 	}
 
 	for (i = 0; i < req->num_pages; i++) {

fs/fuse/fuse_i.h

···
 	 * and hence races in setting them will not cause malfunction
 	 */
 
+	/** Is open/release not implemented by fs? */
+	unsigned no_open:1;
+
 	/** Is fsync not implemented by fs? */
 	unsigned no_fsync:1;
 
···
 void fuse_invalidate_attr(struct inode *inode);
 
 void fuse_invalidate_entry_cache(struct dentry *entry);
+
+void fuse_invalidate_atime(struct inode *inode);
 
 /**
  * Acquire reference to fuse_conn

fs/splice.c

···
 	.get = generic_pipe_buf_get,
 };
 
+static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
+				    struct pipe_buffer *buf)
+{
+	return 1;
+}
+
+/* Pipe buffer operations for a socket and similar. */
+const struct pipe_buf_operations nosteal_pipe_buf_ops = {
+	.can_merge = 0,
+	.map = generic_pipe_buf_map,
+	.unmap = generic_pipe_buf_unmap,
+	.confirm = generic_pipe_buf_confirm,
+	.release = generic_pipe_buf_release,
+	.steal = generic_pipe_buf_nosteal,
+	.get = generic_pipe_buf_get,
+};
+EXPORT_SYMBOL(nosteal_pipe_buf_ops);
+
 static ssize_t kernel_readv(struct file *file, const struct iovec *vec,
 			    unsigned long vlen, loff_t offset)
 {

include/linux/pipe_fs_i.h

···
 int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
 void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
 
+extern const struct pipe_buf_operations nosteal_pipe_buf_ops;
+
 /* for F_SETPIPE_SZ and F_GETPIPE_SZ */
 long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
 struct pipe_inode_info *get_pipe_info(struct file *file);

net/core/skbuff.c

···
 struct kmem_cache *skbuff_head_cache __read_mostly;
 static struct kmem_cache *skbuff_fclone_cache __read_mostly;
 
-static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
-				  struct pipe_buffer *buf)
-{
-	put_page(buf->page);
-}
-
-static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
-				struct pipe_buffer *buf)
-{
-	get_page(buf->page);
-}
-
-static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
-			       struct pipe_buffer *buf)
-{
-	return 1;
-}
-
-
-/* Pipe buffer operations for a socket. */
-static const struct pipe_buf_operations sock_pipe_buf_ops = {
-	.can_merge = 0,
-	.map = generic_pipe_buf_map,
-	.unmap = generic_pipe_buf_unmap,
-	.confirm = generic_pipe_buf_confirm,
-	.release = sock_pipe_buf_release,
-	.steal = sock_pipe_buf_steal,
-	.get = sock_pipe_buf_get,
-};
-
 /**
  *	skb_panic - private function for out-of-line support
  *	@skb:	buffer
···
 		.partial = partial,
 		.nr_pages_max = MAX_SKB_FRAGS,
 		.flags = flags,
-		.ops = &sock_pipe_buf_ops,
+		.ops = &nosteal_pipe_buf_ops,
 		.spd_release = sock_spd_release,
 	};
 	struct sk_buff *frag_iter;