[linux-block.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 <coda@cs.cmu.edu>.
 */

#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/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 coda_file_info *cfi = CODA_FTOC(coda_file);

	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);

	return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
}

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;
	ssize_t ret;

	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);

	host_file = cfi->cfi_container;
	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);
	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 coda_file_info *cfi;
	struct coda_inode_info *cii;
	struct file *host_file;
	struct inode *coda_inode, *host_inode;
	struct coda_vm_ops *cvm_ops;
	int ret;

	cfi = CODA_FTOC(coda_file);
	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
	host_file = cfi->cfi_container;

	if (!host_file->f_op->mmap)
		return -ENODEV;

	if (WARN_ON(coda_file != vma->vm_file))
		return -EIO;

	cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
	if (!cvm_ops)
		return -ENOMEM;

	coda_inode = file_inode(coda_file);
	host_inode = file_inode(host_file);

	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;

	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);
	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);

	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);
	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
	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 <coda@cs.cmu.edu>.
	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>
1da177e4 LT	23
1da177e4 LT	24	#include <linux/coda.h>
8fc8b9df	25	#include "coda_psdev.h"
31a203df	26	#include "coda_linux.h"
c98d8cfb AB	27	#include "coda_int.h"
c98d8cfb AB	28
7fa0a1da JH	29	struct coda_vm_ops {
	30	atomic_t refcnt;
	31	struct file *coda_file;
	32	const struct vm_operations_struct *host_vm_ops;
	33	struct vm_operations_struct vm_ops;
	34	};
	35
1da177e4	36	static ssize_t
c12c49e7	37	coda_file_read_iter(struct kiocb iocb, struct iov_iter to)
1da177e4	38	{
c12c49e7 AV	39	struct file *coda_file = iocb->ki_filp;
c12c49e7 AV	40	struct coda_file_info *cfi = CODA_FTOC(coda_file);
1da177e4	41
1da177e4	42	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
1da177e4	43
18e9710e	44	return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
1da177e4 LT	45	}
1da177e4 LT	46
1da177e4	47	static ssize_t
c12c49e7	48	coda_file_write_iter(struct kiocb iocb, struct iov_iter to)
1da177e4	49	{
c12c49e7 AV	50	struct file *coda_file = iocb->ki_filp;
	51	struct inode *coda_inode = file_inode(coda_file);
	52	struct coda_file_info *cfi = CODA_FTOC(coda_file);
1da177e4 LT	53	struct file *host_file;
	54	ssize_t ret;
	55
1da177e4	56	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
1da177e4	57
c12c49e7	58	host_file = cfi->cfi_container;
03d95eb2	59	file_start_write(host_file);
5955102c	60	inode_lock(coda_inode);
abbb6589	61	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
c12c49e7	62	coda_inode->i_size = file_inode(host_file)->i_size;
1da177e4	63	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
02027d42	64	coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);
5955102c	65	inode_unlock(coda_inode);
03d95eb2	66	file_end_write(host_file);
1da177e4 LT	67	return ret;
	68	}
	69
7fa0a1da JH	70	static void
	71	coda_vm_open(struct vm_area_struct *vma)
	72	{
	73	struct coda_vm_ops *cvm_ops =
	74	container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
	75
	76	atomic_inc(&cvm_ops->refcnt);
	77
	78	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open)
	79	cvm_ops->host_vm_ops->open(vma);
	80	}
	81
	82	static void
	83	coda_vm_close(struct vm_area_struct *vma)
	84	{
	85	struct coda_vm_ops *cvm_ops =
	86	container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
	87
	88	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close)
	89	cvm_ops->host_vm_ops->close(vma);
	90
	91	if (atomic_dec_and_test(&cvm_ops->refcnt)) {
	92	vma->vm_ops = cvm_ops->host_vm_ops;
	93	fput(cvm_ops->coda_file);
	94	kfree(cvm_ops);
	95	}
	96	}
	97
1da177e4 LT	98	static int
	99	coda_file_mmap(struct file coda_file, struct vm_area_struct vma)
	100	{
	101	struct coda_file_info *cfi;
	102	struct coda_inode_info *cii;
	103	struct file *host_file;
	104	struct inode coda_inode, host_inode;
7fa0a1da JH	105	struct coda_vm_ops *cvm_ops;
7fa0a1da JH	106	int ret;
1da177e4 LT	107
	108	cfi = CODA_FTOC(coda_file);
	109	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	110	host_file = cfi->cfi_container;
	111
72c2d531	112	if (!host_file->f_op->mmap)
1da177e4 LT	113	return -ENODEV;
1da177e4 LT	114
7fa0a1da JH	115	if (WARN_ON(coda_file != vma->vm_file))
	116	return -EIO;
	117
	118	cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
	119	if (!cvm_ops)
	120	return -ENOMEM;
	121
496ad9aa AV	122	coda_inode = file_inode(coda_file);
496ad9aa AV	123	host_inode = file_inode(host_file);
b5ce1d83 YA	124
	125	cii = ITOC(coda_inode);
	126	spin_lock(&cii->c_lock);
1da177e4 LT	127	coda_file->f_mapping = host_file->f_mapping;
	128	if (coda_inode->i_mapping == &coda_inode->i_data)
	129	coda_inode->i_mapping = host_inode->i_mapping;
	130
	131	/* only allow additional mmaps as long as userspace isn't changing
	132	* the container file on us! */
b5ce1d83 YA	133	else if (coda_inode->i_mapping != host_inode->i_mapping) {
b5ce1d83 YA	134	spin_unlock(&cii->c_lock);
7fa0a1da	135	kfree(cvm_ops);
1da177e4	136	return -EBUSY;
b5ce1d83	137	}
1da177e4 LT	138
1da177e4 LT	139	/* keep track of how often the coda_inode/host_file has been mmapped */
1da177e4 LT	140	cii->c_mapcount++;
1da177e4 LT	141	cfi->cfi_mapcount++;
b5ce1d83	142	spin_unlock(&cii->c_lock);
1da177e4	143
7fa0a1da JH	144	vma->vm_file = get_file(host_file);
	145	ret = call_mmap(vma->vm_file, vma);
	146
	147	if (ret) {
	148	/* if call_mmap fails, our caller will put coda_file so we
	149	* should drop the reference to the host_file that we got.
	150	*/
	151	fput(host_file);
	152	kfree(cvm_ops);
	153	} else {
	154	/* here we add redirects for the open/close vm_operations */
	155	cvm_ops->host_vm_ops = vma->vm_ops;
	156	if (vma->vm_ops)
	157	cvm_ops->vm_ops = *vma->vm_ops;
	158
	159	cvm_ops->vm_ops.open = coda_vm_open;
	160	cvm_ops->vm_ops.close = coda_vm_close;
	161	cvm_ops->coda_file = coda_file;
	162	atomic_set(&cvm_ops->refcnt, 1);
	163
	164	vma->vm_ops = &cvm_ops->vm_ops;
	165	}
	166	return ret;
1da177e4 LT	167	}
	168
	169	int coda_open(struct inode coda_inode, struct file coda_file)
	170	{
	171	struct file *host_file = NULL;
	172	int error;
	173	unsigned short flags = coda_file->f_flags & (~O_EXCL);
	174	unsigned short coda_flags = coda_flags_to_cflags(flags);
	175	struct coda_file_info *cfi;
	176
1da177e4	177	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
6ecbc4e1	178	if (!cfi)
1da177e4	179	return -ENOMEM;
1da177e4	180
1da177e4	181	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
38c2e437 JH	182	&host_file);
	183	if (!host_file)
	184	error = -EIO;
	185
	186	if (error) {
1da177e4	187	kfree(cfi);
1da177e4 LT	188	return error;
	189	}
	190
	191	host_file->f_flags \|= coda_file->f_flags & (O_APPEND \| O_SYNC);
	192
	193	cfi->cfi_magic = CODA_MAGIC;
	194	cfi->cfi_mapcount = 0;
	195	cfi->cfi_container = host_file;
	196
	197	BUG_ON(coda_file->private_data != NULL);
	198	coda_file->private_data = cfi;
1da177e4 LT	199	return 0;
	200	}
	201
1da177e4 LT	202	int coda_release(struct inode coda_inode, struct file coda_file)
	203	{
	204	unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
	205	unsigned short coda_flags = coda_flags_to_cflags(flags);
	206	struct coda_file_info *cfi;
	207	struct coda_inode_info *cii;
	208	struct inode *host_inode;
f7cc02b8	209	int err;
3cf01f28	210
1da177e4 LT	211	cfi = CODA_FTOC(coda_file);
	212	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	213
d3fec424	214	err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
d76b0d9b	215	coda_flags, coda_file->f_cred->fsuid);
1da177e4	216
496ad9aa	217	host_inode = file_inode(cfi->cfi_container);
1da177e4 LT	218	cii = ITOC(coda_inode);
	219
	220	/* did we mmap this file? */
b5ce1d83	221	spin_lock(&cii->c_lock);
1da177e4 LT	222	if (coda_inode->i_mapping == &host_inode->i_data) {
	223	cii->c_mapcount -= cfi->cfi_mapcount;
	224	if (!cii->c_mapcount)
	225	coda_inode->i_mapping = &coda_inode->i_data;
	226	}
b5ce1d83	227	spin_unlock(&cii->c_lock);
1da177e4 LT	228
	229	fput(cfi->cfi_container);
	230	kfree(coda_file->private_data);
	231	coda_file->private_data = NULL;
	232
d3fec424 JH	233	/* VFS fput ignores the return value from file_operations->release, so
	234	* there is no use returning an error here */
	235	return 0;
1da177e4 LT	236	}
1da177e4 LT	237
02c24a82	238	int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
1da177e4 LT	239	{
1da177e4 LT	240	struct file *host_file;
496ad9aa	241	struct inode *coda_inode = file_inode(coda_file);
1da177e4	242	struct coda_file_info *cfi;
f7cc02b8	243	int err;
1da177e4 LT	244
	245	if (!(S_ISREG(coda_inode->i_mode) \|\| S_ISDIR(coda_inode->i_mode) \|\|
	246	S_ISLNK(coda_inode->i_mode)))
	247	return -EINVAL;
	248
02c24a82 JB	249	err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
	250	if (err)
	251	return err;
5955102c	252	inode_lock(coda_inode);
02c24a82	253
1da177e4 LT	254	cfi = CODA_FTOC(coda_file);
	255	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	256	host_file = cfi->cfi_container;
	257
8018ab05	258	err = vfs_fsync(host_file, datasync);
f7cc02b8	259	if (!err && !datasync)
1da177e4	260	err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
5955102c	261	inode_unlock(coda_inode);
1da177e4 LT	262
	263	return err;
	264	}
	265
4b6f5d20	266	const struct file_operations coda_file_operations = {
1da177e4	267	.llseek = generic_file_llseek,
c12c49e7 AV	268	.read_iter = coda_file_read_iter,
c12c49e7 AV	269	.write_iter = coda_file_write_iter,
1da177e4 LT	270	.mmap = coda_file_mmap,
1da177e4 LT	271	.open = coda_open,
1da177e4 LT	272	.release = coda_release,
1da177e4 LT	273	.fsync = coda_fsync,
82c156f8	274	.splice_read = generic_file_splice_read,
1da177e4	275	};