fs: pass offset and result to backing_file end_write() callback

This is needed for extending fuse inode size after fuse passthrough write.

Suggested-by: Miklos Szeredi <[e-mail]>
Link: https://lore.kernel.org/linux-fsdevel/CAJfpegs=cvZ_NYy6Q_D42XhYS=Sjj5poM1b5TzXzOVvX=[e-mail]/
Signed-off-by: Amir Goldstein <[e-mail]>
Signed-off-by: Miklos Szeredi <[e-mail]>

fs/backing-file.c

···
 	refcount_t ref;
 	struct kiocb *orig_iocb;
 	/* used for aio completion */
-	void (*end_write)(struct file *);
+	void (*end_write)(struct file *, loff_t, ssize_t);
 	struct work_struct work;
 	long res;
 };
···
 	struct kiocb *orig_iocb = aio->orig_iocb;
 
 	if (aio->end_write)
-		aio->end_write(orig_iocb->ki_filp);
+		aio->end_write(orig_iocb->ki_filp, iocb->ki_pos, res);
 
 	orig_iocb->ki_pos = iocb->ki_pos;
 	backing_aio_put(aio);
···
 
 		ret = vfs_iter_write(file, iter, &iocb->ki_pos, rwf);
 		if (ctx->end_write)
-			ctx->end_write(ctx->user_file);
+			ctx->end_write(ctx->user_file, iocb->ki_pos, ret);
 	} else {
 		struct backing_aio *aio;
 
···
 	revert_creds(old_cred);
 
 	if (ctx->end_write)
-		ctx->end_write(ctx->user_file);
+		ctx->end_write(ctx->user_file, ppos ? *ppos : 0, ret);
 
 	return ret;
 }

fs/fuse/passthrough.c

···
 	fuse_invalidate_atime(inode);
 }
 
-static void fuse_file_modified(struct file *file)
+static void fuse_passthrough_end_write(struct file *file, loff_t pos, ssize_t ret)
 {
 	struct inode *inode = file_inode(file);
 
···
 	struct backing_file_ctx ctx = {
 		.cred = ff->cred,
 		.user_file = file,
-		.end_write = fuse_file_modified,
+		.end_write = fuse_passthrough_end_write,
 	};
 
 	pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu\n", __func__,
···
 	struct backing_file_ctx ctx = {
 		.cred = ff->cred,
 		.user_file = out,
-		.end_write = fuse_file_modified,
+		.end_write = fuse_passthrough_end_write,
 	};
 
 	pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu, flags=0x%x\n", __func__,

fs/overlayfs/file.c

···
 	ovl_copyattr(file_inode(file));
 }
 
+static void ovl_file_end_write(struct file *file, loff_t pos, ssize_t ret)
+{
+	ovl_file_modified(file);
+}
+
 static void ovl_file_accessed(struct file *file)
 {
 	struct inode *inode, *upperinode;
···
 	struct backing_file_ctx ctx = {
 		.cred = ovl_creds(inode->i_sb),
 		.user_file = file,
-		.end_write = ovl_file_modified,
+		.end_write = ovl_file_end_write,
 	};
 
 	if (!iov_iter_count(iter))
···
 	struct backing_file_ctx ctx = {
 		.cred = ovl_creds(inode->i_sb),
 		.user_file = out,
-		.end_write = ovl_file_modified,
+		.end_write = ovl_file_end_write,
 	};
 
 	inode_lock(inode);

include/linux/backing-file.h

···
 	const struct cred *cred;
 	struct file *user_file;
 	void (*accessed)(struct file *);
-	void (*end_write)(struct file *);
+	void (*end_write)(struct file *, loff_t, ssize_t);
 };
 
 struct file *backing_file_open(const struct path *user_path, int flags,