fs/coda/file.c - linux - Git at Google

 // 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/splice.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 = inode_set_ctime_current(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 ssize_t
 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
 		      struct pipe_inode_info *pipe,
 		      size_t len, unsigned int flags)
 {
 	struct inode *coda_inode = file_inode(coda_file);
 	struct coda_file_info *cfi = coda_ftoc(coda_file);
 	struct file *in = cfi->cfi_container;
 	loff_t ki_pos = *ppos;
 	ssize_t ret;

 	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
 				  &cfi->cfi_access_intent,
 				  len, ki_pos, CODA_ACCESS_TYPE_READ);
 	if (ret)
 		goto finish_read;

 	ret = vfs_splice_read(in, ppos, pipe, len, flags);

 finish_read:
 	venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
 			    &cfi->cfi_access_intent,
 			    len, ki_pos, CODA_ACCESS_TYPE_READ_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	= coda_file_splice_read,
 };
	// 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/splice.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 = inode_set_ctime_current(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 ssize_t
	coda_file_splice_read(struct file coda_file, loff_t ppos,
	struct pipe_inode_info *pipe,
	size_t len, unsigned int flags)
	{
	struct inode *coda_inode = file_inode(coda_file);
	struct coda_file_info *cfi = coda_ftoc(coda_file);
	struct file *in = cfi->cfi_container;
	loff_t ki_pos = *ppos;
	ssize_t ret;

	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
	&cfi->cfi_access_intent,
	len, ki_pos, CODA_ACCESS_TYPE_READ);
	if (ret)
	goto finish_read;

	ret = vfs_splice_read(in, ppos, pipe, len, flags);

	finish_read:
	venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
	&cfi->cfi_access_intent,
	len, ki_pos, CODA_ACCESS_TYPE_READ_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 = coda_file_splice_read,
	};