1 files changed, 306 insertions, 0 deletions
diff --git a/fs/coda/file.c b/fs/coda/file.c
new file mode 100644
index 000000000..3f3c81e6b
--- /dev/null
+++ b/fs/coda/file.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * File operations for Coda.
+ * Original version: (C) 1996 Peter Braam 
+ * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
+ *
+ * Carnegie Mellon encourages users of this code to contribute improvements
+ * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
+ */
+
+#include <linux/refcount.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/stat.h>
+#include <linux/cred.h>
+#include <linux/errno.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+
+#include <linux/coda.h>
+#include "coda_psdev.h"
+#include "coda_linux.h"
+#include "coda_int.h"
+
+struct coda_vm_ops {
+	refcount_t refcnt;
+	struct file *coda_file;
+	const struct vm_operations_struct *host_vm_ops;
+	struct vm_operations_struct vm_ops;
+};
+
+static ssize_t
+coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *coda_file = iocb->ki_filp;
+	struct inode *coda_inode = file_inode(coda_file);
+	struct coda_file_info *cfi = coda_ftoc(coda_file);
+	loff_t ki_pos = iocb->ki_pos;
+	size_t count = iov_iter_count(to);
+	ssize_t ret;
+
+	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
+				  &cfi->cfi_access_intent,
+				  count, ki_pos, CODA_ACCESS_TYPE_READ);
+	if (ret)
+		goto finish_read;
+
+	ret = vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
+
+finish_read:
+	venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
+			    &cfi->cfi_access_intent,
+			    count, ki_pos, CODA_ACCESS_TYPE_READ_FINISH);
+	return ret;
+}
+
+static ssize_t
+coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *coda_file = iocb->ki_filp;
+	struct inode *coda_inode = file_inode(coda_file);
+	struct coda_file_info *cfi = coda_ftoc(coda_file);
+	struct file *host_file = cfi->cfi_container;
+	loff_t ki_pos = iocb->ki_pos;
+	size_t count = iov_iter_count(to);
+	ssize_t ret;
+
+	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
+				  &cfi->cfi_access_intent,
+				  count, ki_pos, CODA_ACCESS_TYPE_WRITE);
+	if (ret)
+		goto finish_write;
+
+	file_start_write(host_file);
+	inode_lock(coda_inode);
+	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
+	coda_inode->i_size = file_inode(host_file)->i_size;
+	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
+	coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);
+	inode_unlock(coda_inode);
+	file_end_write(host_file);
+
+finish_write:
+	venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
+			    &cfi->cfi_access_intent,
+			    count, ki_pos, CODA_ACCESS_TYPE_WRITE_FINISH);
+	return ret;
+}
+
+static void
+coda_vm_open(struct vm_area_struct *vma)
+{
+	struct coda_vm_ops *cvm_ops =
+		container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
+
+	refcount_inc(&cvm_ops->refcnt);
+
+	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open)
+		cvm_ops->host_vm_ops->open(vma);
+}
+
+static void
+coda_vm_close(struct vm_area_struct *vma)
+{
+	struct coda_vm_ops *cvm_ops =
+		container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
+
+	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close)
+		cvm_ops->host_vm_ops->close(vma);
+
+	if (refcount_dec_and_test(&cvm_ops->refcnt)) {
+		vma->vm_ops = cvm_ops->host_vm_ops;
+		fput(cvm_ops->coda_file);
+		kfree(cvm_ops);
+	}
+}
+
+static int
+coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
+{
+	struct inode *coda_inode = file_inode(coda_file);
+	struct coda_file_info *cfi = coda_ftoc(coda_file);
+	struct file *host_file = cfi->cfi_container;
+	struct inode *host_inode = file_inode(host_file);
+	struct coda_inode_info *cii;
+	struct coda_vm_ops *cvm_ops;
+	loff_t ppos;
+	size_t count;
+	int ret;
+
+	if (!host_file->f_op->mmap)
+		return -ENODEV;
+
+	if (WARN_ON(coda_file != vma->vm_file))
+		return -EIO;
+
+	count = vma->vm_end - vma->vm_start;
+	ppos = vma->vm_pgoff * PAGE_SIZE;
+
+	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
+				  &cfi->cfi_access_intent,
+				  count, ppos, CODA_ACCESS_TYPE_MMAP);
+	if (ret)
+		return ret;
+
+	cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
+	if (!cvm_ops)
+		return -ENOMEM;
+
+	cii = ITOC(coda_inode);
+	spin_lock(&cii->c_lock);
+	coda_file->f_mapping = host_file->f_mapping;
+	if (coda_inode->i_mapping == &coda_inode->i_data)
+		coda_inode->i_mapping = host_inode->i_mapping;
+
+	/* only allow additional mmaps as long as userspace isn't changing
+	 * the container file on us! */
+	else if (coda_inode->i_mapping != host_inode->i_mapping) {
+		spin_unlock(&cii->c_lock);
+		kfree(cvm_ops);
+		return -EBUSY;
+	}
+
+	/* keep track of how often the coda_inode/host_file has been mmapped */
+	cii->c_mapcount++;
+	cfi->cfi_mapcount++;
+	spin_unlock(&cii->c_lock);
+
+	vma->vm_file = get_file(host_file);
+	ret = call_mmap(vma->vm_file, vma);
+
+	if (ret) {
+		/* if call_mmap fails, our caller will put host_file so we
+		 * should drop the reference to the coda_file that we got.
+		 */
+		fput(coda_file);
+		kfree(cvm_ops);
+	} else {
+		/* here we add redirects for the open/close vm_operations */
+		cvm_ops->host_vm_ops = vma->vm_ops;
+		if (vma->vm_ops)
+			cvm_ops->vm_ops = *vma->vm_ops;
+
+		cvm_ops->vm_ops.open = coda_vm_open;
+		cvm_ops->vm_ops.close = coda_vm_close;
+		cvm_ops->coda_file = coda_file;
+		refcount_set(&cvm_ops->refcnt, 1);
+
+		vma->vm_ops = &cvm_ops->vm_ops;
+	}
+	return ret;
+}
+
+int coda_open(struct inode *coda_inode, struct file *coda_file)
+{
+	struct file *host_file = NULL;
+	int error;
+	unsigned short flags = coda_file->f_flags & (~O_EXCL);
+	unsigned short coda_flags = coda_flags_to_cflags(flags);
+	struct coda_file_info *cfi;
+
+	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
+	if (!cfi)
+		return -ENOMEM;
+
+	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
+			   &host_file);
+	if (!host_file)
+		error = -EIO;
+
+	if (error) {
+		kfree(cfi);
+		return error;
+	}
+
+	host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
+
+	cfi->cfi_magic = CODA_MAGIC;
+	cfi->cfi_mapcount = 0;
+	cfi->cfi_container = host_file;
+	/* assume access intents are supported unless we hear otherwise */
+	cfi->cfi_access_intent = true;
+
+	BUG_ON(coda_file->private_data != NULL);
+	coda_file->private_data = cfi;
+	return 0;
+}
+
+int coda_release(struct inode *coda_inode, struct file *coda_file)
+{
+	unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
+	unsigned short coda_flags = coda_flags_to_cflags(flags);
+	struct coda_file_info *cfi;
+	struct coda_inode_info *cii;
+	struct inode *host_inode;
+
+	cfi = coda_ftoc(coda_file);
+
+	venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
+			  coda_flags, coda_file->f_cred->fsuid);
+
+	host_inode = file_inode(cfi->cfi_container);
+	cii = ITOC(coda_inode);
+
+	/* did we mmap this file? */
+	spin_lock(&cii->c_lock);
+	if (coda_inode->i_mapping == &host_inode->i_data) {
+		cii->c_mapcount -= cfi->cfi_mapcount;
+		if (!cii->c_mapcount)
+			coda_inode->i_mapping = &coda_inode->i_data;
+	}
+	spin_unlock(&cii->c_lock);
+
+	fput(cfi->cfi_container);
+	kfree(coda_file->private_data);
+	coda_file->private_data = NULL;
+
+	/* VFS fput ignores the return value from file_operations->release, so
+	 * there is no use returning an error here */
+	return 0;
+}
+
+int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
+{
+	struct file *host_file;
+	struct inode *coda_inode = file_inode(coda_file);
+	struct coda_file_info *cfi;
+	int err;
+
+	if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
+	      S_ISLNK(coda_inode->i_mode)))
+		return -EINVAL;
+
+	err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
+	if (err)
+		return err;
+	inode_lock(coda_inode);
+
+	cfi = coda_ftoc(coda_file);
+	host_file = cfi->cfi_container;
+
+	err = vfs_fsync(host_file, datasync);
+	if (!err && !datasync)
+		err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
+	inode_unlock(coda_inode);
+
+	return err;
+}
+
+const struct file_operations coda_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read_iter	= coda_file_read_iter,
+	.write_iter	= coda_file_write_iter,
+	.mmap		= coda_file_mmap,
+	.open		= coda_open,
+	.release	= coda_release,
+	.fsync		= coda_fsync,
+	.splice_read	= generic_file_splice_read,
+};