[linux.git] / fs / coda / file.c

// 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 <[email protected]>.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/file.h>
#include <linux/fs.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 {
	atomic_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);

	atomic_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 (atomic_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 coda_file so we
		 * should drop the reference to the host_file that we got.
		 */
		fput(host_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;
		atomic_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;
	int err;

	cfi = coda_ftoc(coda_file);

	err = 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,
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* File operations for Coda.
	4	* Original version: (C) 1996 Peter Braam
	5	* Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
	6	*
	7	* Carnegie Mellon encourages users of this code to contribute improvements
	8	* to the Coda project. Contact Peter Braam <[email protected]>.
	9	*/
	10
	11	#include <linux/types.h>
	12	#include <linux/kernel.h>
	13	#include <linux/time.h>
	14	#include <linux/file.h>
	15	#include <linux/fs.h>
	16	#include <linux/stat.h>
7596b27d	17	#include <linux/cred.h>
1da177e4	18	#include <linux/errno.h>
b5ce1d83	19	#include <linux/spinlock.h>
1da177e4	20	#include <linux/string.h>
5a0e3ad6	21	#include <linux/slab.h>
834b46c3	22	#include <linux/uaccess.h>
a9fba24c	23	#include <linux/uio.h>
1da177e4 LT	24
1da177e4 LT	25	#include <linux/coda.h>
8fc8b9df	26	#include "coda_psdev.h"
31a203df	27	#include "coda_linux.h"
c98d8cfb AB	28	#include "coda_int.h"
c98d8cfb AB	29
7fa0a1da JH	30	struct coda_vm_ops {
	31	atomic_t refcnt;
	32	struct file *coda_file;
	33	const struct vm_operations_struct *host_vm_ops;
	34	struct vm_operations_struct vm_ops;
	35	};
	36
1da177e4	37	static ssize_t
c12c49e7	38	coda_file_read_iter(struct kiocb iocb, struct iov_iter to)
1da177e4	39	{
c12c49e7	40	struct file *coda_file = iocb->ki_filp;
a9fba24c	41	struct inode *coda_inode = file_inode(coda_file);
5bb44810	42	struct coda_file_info *cfi = coda_ftoc(coda_file);
a9fba24c PC	43	loff_t ki_pos = iocb->ki_pos;
	44	size_t count = iov_iter_count(to);
	45	ssize_t ret;
	46
	47	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
	48	&cfi->cfi_access_intent,
	49	count, ki_pos, CODA_ACCESS_TYPE_READ);
	50	if (ret)
	51	goto finish_read;
	52
	53	ret = vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
1da177e4	54
a9fba24c PC	55	finish_read:
	56	venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
	57	&cfi->cfi_access_intent,
	58	count, ki_pos, CODA_ACCESS_TYPE_READ_FINISH);
	59	return ret;
1da177e4 LT	60	}
1da177e4 LT	61
1da177e4	62	static ssize_t
c12c49e7	63	coda_file_write_iter(struct kiocb iocb, struct iov_iter to)
1da177e4	64	{
c12c49e7 AV	65	struct file *coda_file = iocb->ki_filp;
c12c49e7 AV	66	struct inode *coda_inode = file_inode(coda_file);
5bb44810	67	struct coda_file_info *cfi = coda_ftoc(coda_file);
a9fba24c PC	68	struct file *host_file = cfi->cfi_container;
	69	loff_t ki_pos = iocb->ki_pos;
	70	size_t count = iov_iter_count(to);
1da177e4 LT	71	ssize_t ret;
1da177e4 LT	72
a9fba24c PC	73	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
	74	&cfi->cfi_access_intent,
	75	count, ki_pos, CODA_ACCESS_TYPE_WRITE);
	76	if (ret)
	77	goto finish_write;
	78
03d95eb2	79	file_start_write(host_file);
5955102c	80	inode_lock(coda_inode);
abbb6589	81	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
c12c49e7	82	coda_inode->i_size = file_inode(host_file)->i_size;
1da177e4	83	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
02027d42	84	coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);
5955102c	85	inode_unlock(coda_inode);
03d95eb2	86	file_end_write(host_file);
a9fba24c PC	87
	88	finish_write:
	89	venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
	90	&cfi->cfi_access_intent,
	91	count, ki_pos, CODA_ACCESS_TYPE_WRITE_FINISH);
1da177e4 LT	92	return ret;
	93	}
	94
7fa0a1da JH	95	static void
	96	coda_vm_open(struct vm_area_struct *vma)
	97	{
	98	struct coda_vm_ops *cvm_ops =
	99	container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
	100
	101	atomic_inc(&cvm_ops->refcnt);
	102
	103	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open)
	104	cvm_ops->host_vm_ops->open(vma);
	105	}
	106
	107	static void
	108	coda_vm_close(struct vm_area_struct *vma)
	109	{
	110	struct coda_vm_ops *cvm_ops =
	111	container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
	112
	113	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close)
	114	cvm_ops->host_vm_ops->close(vma);
	115
	116	if (atomic_dec_and_test(&cvm_ops->refcnt)) {
	117	vma->vm_ops = cvm_ops->host_vm_ops;
	118	fput(cvm_ops->coda_file);
	119	kfree(cvm_ops);
	120	}
	121	}
	122
1da177e4 LT	123	static int
	124	coda_file_mmap(struct file coda_file, struct vm_area_struct vma)
	125	{
a9fba24c PC	126	struct inode *coda_inode = file_inode(coda_file);
	127	struct coda_file_info *cfi = coda_ftoc(coda_file);
	128	struct file *host_file = cfi->cfi_container;
	129	struct inode *host_inode = file_inode(host_file);
1da177e4	130	struct coda_inode_info *cii;
7fa0a1da	131	struct coda_vm_ops *cvm_ops;
a9fba24c PC	132	loff_t ppos;
a9fba24c PC	133	size_t count;
7fa0a1da	134	int ret;
1da177e4	135
72c2d531	136	if (!host_file->f_op->mmap)
1da177e4 LT	137	return -ENODEV;
1da177e4 LT	138
7fa0a1da JH	139	if (WARN_ON(coda_file != vma->vm_file))
	140	return -EIO;
	141
a9fba24c PC	142	count = vma->vm_end - vma->vm_start;
	143	ppos = vma->vm_pgoff * PAGE_SIZE;
	144
	145	ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
	146	&cfi->cfi_access_intent,
	147	count, ppos, CODA_ACCESS_TYPE_MMAP);
	148	if (ret)
	149	return ret;
	150
7fa0a1da JH	151	cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
	152	if (!cvm_ops)
	153	return -ENOMEM;
	154
b5ce1d83 YA	155	cii = ITOC(coda_inode);
b5ce1d83 YA	156	spin_lock(&cii->c_lock);
1da177e4 LT	157	coda_file->f_mapping = host_file->f_mapping;
	158	if (coda_inode->i_mapping == &coda_inode->i_data)
	159	coda_inode->i_mapping = host_inode->i_mapping;
	160
	161	/* only allow additional mmaps as long as userspace isn't changing
	162	* the container file on us! */
b5ce1d83 YA	163	else if (coda_inode->i_mapping != host_inode->i_mapping) {
b5ce1d83 YA	164	spin_unlock(&cii->c_lock);
7fa0a1da	165	kfree(cvm_ops);
1da177e4	166	return -EBUSY;
b5ce1d83	167	}
1da177e4 LT	168
1da177e4 LT	169	/* keep track of how often the coda_inode/host_file has been mmapped */
1da177e4 LT	170	cii->c_mapcount++;
1da177e4 LT	171	cfi->cfi_mapcount++;
b5ce1d83	172	spin_unlock(&cii->c_lock);
1da177e4	173
7fa0a1da JH	174	vma->vm_file = get_file(host_file);
	175	ret = call_mmap(vma->vm_file, vma);
	176
	177	if (ret) {
	178	/* if call_mmap fails, our caller will put coda_file so we
	179	* should drop the reference to the host_file that we got.
	180	*/
	181	fput(host_file);
	182	kfree(cvm_ops);
	183	} else {
	184	/* here we add redirects for the open/close vm_operations */
	185	cvm_ops->host_vm_ops = vma->vm_ops;
	186	if (vma->vm_ops)
	187	cvm_ops->vm_ops = *vma->vm_ops;
	188
	189	cvm_ops->vm_ops.open = coda_vm_open;
	190	cvm_ops->vm_ops.close = coda_vm_close;
	191	cvm_ops->coda_file = coda_file;
	192	atomic_set(&cvm_ops->refcnt, 1);
	193
	194	vma->vm_ops = &cvm_ops->vm_ops;
	195	}
	196	return ret;
1da177e4 LT	197	}
	198
	199	int coda_open(struct inode coda_inode, struct file coda_file)
	200	{
	201	struct file *host_file = NULL;
	202	int error;
	203	unsigned short flags = coda_file->f_flags & (~O_EXCL);
	204	unsigned short coda_flags = coda_flags_to_cflags(flags);
	205	struct coda_file_info *cfi;
	206
1da177e4	207	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
6ecbc4e1	208	if (!cfi)
1da177e4	209	return -ENOMEM;
1da177e4	210
1da177e4	211	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
38c2e437 JH	212	&host_file);
	213	if (!host_file)
	214	error = -EIO;
	215
	216	if (error) {
1da177e4	217	kfree(cfi);
1da177e4 LT	218	return error;
	219	}
	220
	221	host_file->f_flags \|= coda_file->f_flags & (O_APPEND \| O_SYNC);
	222
	223	cfi->cfi_magic = CODA_MAGIC;
	224	cfi->cfi_mapcount = 0;
	225	cfi->cfi_container = host_file;
a9fba24c PC	226	/* assume access intents are supported unless we hear otherwise */
a9fba24c PC	227	cfi->cfi_access_intent = true;
1da177e4 LT	228
	229	BUG_ON(coda_file->private_data != NULL);
	230	coda_file->private_data = cfi;
1da177e4 LT	231	return 0;
	232	}
	233
1da177e4 LT	234	int coda_release(struct inode coda_inode, struct file coda_file)
	235	{
	236	unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
	237	unsigned short coda_flags = coda_flags_to_cflags(flags);
	238	struct coda_file_info *cfi;
	239	struct coda_inode_info *cii;
	240	struct inode *host_inode;
f7cc02b8	241	int err;
3cf01f28	242
5bb44810	243	cfi = coda_ftoc(coda_file);
1da177e4	244
d3fec424	245	err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
d76b0d9b	246	coda_flags, coda_file->f_cred->fsuid);
1da177e4	247
496ad9aa	248	host_inode = file_inode(cfi->cfi_container);
1da177e4 LT	249	cii = ITOC(coda_inode);
	250
	251	/* did we mmap this file? */
b5ce1d83	252	spin_lock(&cii->c_lock);
1da177e4 LT	253	if (coda_inode->i_mapping == &host_inode->i_data) {
	254	cii->c_mapcount -= cfi->cfi_mapcount;
	255	if (!cii->c_mapcount)
	256	coda_inode->i_mapping = &coda_inode->i_data;
	257	}
b5ce1d83	258	spin_unlock(&cii->c_lock);
1da177e4 LT	259
	260	fput(cfi->cfi_container);
	261	kfree(coda_file->private_data);
	262	coda_file->private_data = NULL;
	263
d3fec424 JH	264	/* VFS fput ignores the return value from file_operations->release, so
	265	* there is no use returning an error here */
	266	return 0;
1da177e4 LT	267	}
1da177e4 LT	268
02c24a82	269	int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
1da177e4 LT	270	{
1da177e4 LT	271	struct file *host_file;
496ad9aa	272	struct inode *coda_inode = file_inode(coda_file);
1da177e4	273	struct coda_file_info *cfi;
f7cc02b8	274	int err;
1da177e4 LT	275
	276	if (!(S_ISREG(coda_inode->i_mode) \|\| S_ISDIR(coda_inode->i_mode) \|\|
	277	S_ISLNK(coda_inode->i_mode)))
	278	return -EINVAL;
	279
02c24a82 JB	280	err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
	281	if (err)
	282	return err;
5955102c	283	inode_lock(coda_inode);
02c24a82	284
5bb44810	285	cfi = coda_ftoc(coda_file);
1da177e4 LT	286	host_file = cfi->cfi_container;
1da177e4 LT	287
8018ab05	288	err = vfs_fsync(host_file, datasync);
f7cc02b8	289	if (!err && !datasync)
1da177e4	290	err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
5955102c	291	inode_unlock(coda_inode);
1da177e4 LT	292
	293	return err;
	294	}
	295
4b6f5d20	296	const struct file_operations coda_file_operations = {
1da177e4	297	.llseek = generic_file_llseek,
c12c49e7 AV	298	.read_iter = coda_file_read_iter,
c12c49e7 AV	299	.write_iter = coda_file_write_iter,
1da177e4 LT	300	.mmap = coda_file_mmap,
1da177e4 LT	301	.open = coda_open,
1da177e4 LT	302	.release = coda_release,
1da177e4 LT	303	.fsync = coda_fsync,
82c156f8	304	.splice_read = generic_file_splice_read,
1da177e4	305	};