1 files changed, 94 insertions, 94 deletions

diff --git a/fs/backing-file.c b/fs/backing-file.c
index afb557446c27..45da8600d564 100644
--- a/fs/backing-file.c
+++ b/fs/backing-file.c
@@ -41,7 +41,7 @@ struct file *backing_file_open(const struct path *user_path, int flags,
 		return f;
 
 	path_get(user_path);
-	*backing_file_user_path(f) = *user_path;
+	backing_file_set_user_path(f, user_path);
 	error = vfs_open(real_path, f);
 	if (error) {
 		fput(f);
@@ -65,7 +65,7 @@ struct file *backing_tmpfile_open(const struct path *user_path, int flags,
 		return f;
 
 	path_get(user_path);
-	*backing_file_user_path(f) = *user_path;
+	backing_file_set_user_path(f, user_path);
 	error = vfs_tmpfile(real_idmap, real_parentpath, f, mode);
 	if (error) {
 		fput(f);
@@ -80,7 +80,7 @@ struct backing_aio {
 	refcount_t ref;
 	struct kiocb *orig_iocb;
 	/* used for aio completion */
-	void (*end_write)(struct file *);
+	void (*end_write)(struct kiocb *iocb, ssize_t);
 	struct work_struct work;
 	long res;
 };
@@ -108,10 +108,10 @@ static void backing_aio_cleanup(struct backing_aio *aio, long res)
 	struct kiocb *iocb = &aio->iocb;
 	struct kiocb *orig_iocb = aio->orig_iocb;
 
+	orig_iocb->ki_pos = iocb->ki_pos;
 	if (aio->end_write)
-		aio->end_write(orig_iocb->ki_filp);
+		aio->end_write(orig_iocb, res);
 
-	orig_iocb->ki_pos = iocb->ki_pos;
 	backing_aio_put(aio);
 }
 
@@ -157,13 +157,37 @@ static int backing_aio_init_wq(struct kiocb *iocb)
 	return sb_init_dio_done_wq(sb);
 }
 
+static int do_backing_file_read_iter(struct file *file, struct iov_iter *iter,
+				     struct kiocb *iocb, int flags)
+{
+	struct backing_aio *aio = NULL;
+	int ret;
+
+	if (is_sync_kiocb(iocb)) {
+		rwf_t rwf = iocb_to_rw_flags(flags);
+
+		return vfs_iter_read(file, iter, &iocb->ki_pos, rwf);
+	}
+
+	aio = kmem_cache_zalloc(backing_aio_cachep, GFP_KERNEL);
+	if (!aio)
+		return -ENOMEM;
+
+	aio->orig_iocb = iocb;
+	kiocb_clone(&aio->iocb, iocb, get_file(file));
+	aio->iocb.ki_complete = backing_aio_rw_complete;
+	refcount_set(&aio->ref, 2);
+	ret = vfs_iocb_iter_read(file, &aio->iocb, iter);
+	backing_aio_put(aio);
+	if (ret != -EIOCBQUEUED)
+		backing_aio_cleanup(aio, ret);
+	return ret;
+}
 
 ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
 			       struct kiocb *iocb, int flags,
 			       struct backing_file_ctx *ctx)
 {
-	struct backing_aio *aio = NULL;
-	const struct cred *old_cred;
 	ssize_t ret;
 
 	if (WARN_ON_ONCE(!(file->f_mode & FMODE_BACKING)))
@@ -176,41 +200,57 @@ ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
 	    !(file->f_mode & FMODE_CAN_ODIRECT))
 		return -EINVAL;
 
-	old_cred = override_creds(ctx->cred);
+	scoped_with_creds(ctx->cred)
+		ret = do_backing_file_read_iter(file, iter, iocb, flags);
+
+	if (ctx->accessed)
+		ctx->accessed(iocb->ki_filp);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(backing_file_read_iter);
+
+static int do_backing_file_write_iter(struct file *file, struct iov_iter *iter,
+				      struct kiocb *iocb, int flags,
+				      void (*end_write)(struct kiocb *, ssize_t))
+{
+	struct backing_aio *aio;
+	int ret;
+
 	if (is_sync_kiocb(iocb)) {
 		rwf_t rwf = iocb_to_rw_flags(flags);
 
-		ret = vfs_iter_read(file, iter, &iocb->ki_pos, rwf);
-	} else {
-		ret = -ENOMEM;
-		aio = kmem_cache_zalloc(backing_aio_cachep, GFP_KERNEL);
-		if (!aio)
-			goto out;
-
-		aio->orig_iocb = iocb;
-		kiocb_clone(&aio->iocb, iocb, get_file(file));
-		aio->iocb.ki_complete = backing_aio_rw_complete;
-		refcount_set(&aio->ref, 2);
-		ret = vfs_iocb_iter_read(file, &aio->iocb, iter);
-		backing_aio_put(aio);
-		if (ret != -EIOCBQUEUED)
-			backing_aio_cleanup(aio, ret);
+		ret = vfs_iter_write(file, iter, &iocb->ki_pos, rwf);
+		if (end_write)
+			end_write(iocb, ret);
+		return ret;
 	}
-out:
-	revert_creds(old_cred);
 
-	if (ctx->accessed)
-		ctx->accessed(ctx->user_file);
+	ret = backing_aio_init_wq(iocb);
+	if (ret)
+		return ret;
 
+	aio = kmem_cache_zalloc(backing_aio_cachep, GFP_KERNEL);
+	if (!aio)
+		return -ENOMEM;
+
+	aio->orig_iocb = iocb;
+	aio->end_write = end_write;
+	kiocb_clone(&aio->iocb, iocb, get_file(file));
+	aio->iocb.ki_flags = flags;
+	aio->iocb.ki_complete = backing_aio_queue_completion;
+	refcount_set(&aio->ref, 2);
+	ret = vfs_iocb_iter_write(file, &aio->iocb, iter);
+	backing_aio_put(aio);
+	if (ret != -EIOCBQUEUED)
+		backing_aio_cleanup(aio, ret);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(backing_file_read_iter);
 
 ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
 				struct kiocb *iocb, int flags,
 				struct backing_file_ctx *ctx)
 {
-	const struct cred *old_cred;
 	ssize_t ret;
 
 	if (WARN_ON_ONCE(!(file->f_mode & FMODE_BACKING)))
@@ -219,7 +259,7 @@ ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
 	if (!iov_iter_count(iter))
 		return 0;
 
-	ret = file_remove_privs(ctx->user_file);
+	ret = file_remove_privs(iocb->ki_filp);
 	if (ret)
 		return ret;
 
@@ -227,94 +267,56 @@ ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
 	    !(file->f_mode & FMODE_CAN_ODIRECT))
 		return -EINVAL;
 
-	/*
-	 * Stacked filesystems don't support deferred completions, don't copy
-	 * this property in case it is set by the issuer.
-	 */
-	flags &= ~IOCB_DIO_CALLER_COMP;
-
-	old_cred = override_creds(ctx->cred);
-	if (is_sync_kiocb(iocb)) {
-		rwf_t rwf = iocb_to_rw_flags(flags);
-
-		ret = vfs_iter_write(file, iter, &iocb->ki_pos, rwf);
-		if (ctx->end_write)
-			ctx->end_write(ctx->user_file);
-	} else {
-		struct backing_aio *aio;
-
-		ret = backing_aio_init_wq(iocb);
-		if (ret)
-			goto out;
-
-		ret = -ENOMEM;
-		aio = kmem_cache_zalloc(backing_aio_cachep, GFP_KERNEL);
-		if (!aio)
-			goto out;
-
-		aio->orig_iocb = iocb;
-		aio->end_write = ctx->end_write;
-		kiocb_clone(&aio->iocb, iocb, get_file(file));
-		aio->iocb.ki_flags = flags;
-		aio->iocb.ki_complete = backing_aio_queue_completion;
-		refcount_set(&aio->ref, 2);
-		ret = vfs_iocb_iter_write(file, &aio->iocb, iter);
-		backing_aio_put(aio);
-		if (ret != -EIOCBQUEUED)
-			backing_aio_cleanup(aio, ret);
-	}
-out:
-	revert_creds(old_cred);
-
-	return ret;
+	scoped_with_creds(ctx->cred)
+		return do_backing_file_write_iter(file, iter, iocb, flags, ctx->end_write);
 }
 EXPORT_SYMBOL_GPL(backing_file_write_iter);
 
-ssize_t backing_file_splice_read(struct file *in, loff_t *ppos,
+ssize_t backing_file_splice_read(struct file *in, struct kiocb *iocb,
 				 struct pipe_inode_info *pipe, size_t len,
 				 unsigned int flags,
 				 struct backing_file_ctx *ctx)
 {
-	const struct cred *old_cred;
 	ssize_t ret;
 
 	if (WARN_ON_ONCE(!(in->f_mode & FMODE_BACKING)))
 		return -EIO;
 
-	old_cred = override_creds(ctx->cred);
-	ret = vfs_splice_read(in, ppos, pipe, len, flags);
-	revert_creds(old_cred);
+	scoped_with_creds(ctx->cred)
+		ret = vfs_splice_read(in, &iocb->ki_pos, pipe, len, flags);
 
 	if (ctx->accessed)
-		ctx->accessed(ctx->user_file);
+		ctx->accessed(iocb->ki_filp);
 
 	return ret;
 }
 EXPORT_SYMBOL_GPL(backing_file_splice_read);
 
 ssize_t backing_file_splice_write(struct pipe_inode_info *pipe,
-				  struct file *out, loff_t *ppos, size_t len,
-				  unsigned int flags,
+				  struct file *out, struct kiocb *iocb,
+				  size_t len, unsigned int flags,
 				  struct backing_file_ctx *ctx)
 {
-	const struct cred *old_cred;
 	ssize_t ret;
 
 	if (WARN_ON_ONCE(!(out->f_mode & FMODE_BACKING)))
 		return -EIO;
 
-	ret = file_remove_privs(ctx->user_file);
+	if (!out->f_op->splice_write)
+		return -EINVAL;
+
+	ret = file_remove_privs(iocb->ki_filp);
 	if (ret)
 		return ret;
 
-	old_cred = override_creds(ctx->cred);
-	file_start_write(out);
-	ret = iter_file_splice_write(pipe, out, ppos, len, flags);
-	file_end_write(out);
-	revert_creds(old_cred);
+	scoped_with_creds(ctx->cred) {
+		file_start_write(out);
+		ret = out->f_op->splice_write(pipe, out, &iocb->ki_pos, len, flags);
+		file_end_write(out);
+	}
 
 	if (ctx->end_write)
-		ctx->end_write(ctx->user_file);
+		ctx->end_write(iocb, ret);
 
 	return ret;
 }
@@ -323,24 +325,22 @@ EXPORT_SYMBOL_GPL(backing_file_splice_write);
 int backing_file_mmap(struct file *file, struct vm_area_struct *vma,
 		      struct backing_file_ctx *ctx)
 {
-	const struct cred *old_cred;
+	struct file *user_file = vma->vm_file;
 	int ret;
 
-	if (WARN_ON_ONCE(!(file->f_mode & FMODE_BACKING)) ||
-	    WARN_ON_ONCE(ctx->user_file != vma->vm_file))
+	if (WARN_ON_ONCE(!(file->f_mode & FMODE_BACKING)))
 		return -EIO;
 
-	if (!file->f_op->mmap)
+	if (!can_mmap_file(file))
 		return -ENODEV;
 
 	vma_set_file(vma, file);
 
-	old_cred = override_creds(ctx->cred);
-	ret = call_mmap(vma->vm_file, vma);
-	revert_creds(old_cred);
+	scoped_with_creds(ctx->cred)
+		ret = vfs_mmap(vma->vm_file, vma);
 
 	if (ctx->accessed)
-		ctx->accessed(ctx->user_file);
+		ctx->accessed(user_file);
 
 	return ret;
 }