[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 <linux/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>
1da177e4	25	#include <linux/coda_psdev.h>
1da177e4	26
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 AV	40	struct file *coda_file = iocb->ki_filp;
c12c49e7 AV	41	struct coda_file_info *cfi = CODA_FTOC(coda_file);
1da177e4	42
1da177e4	43	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
1da177e4	44
18e9710e	45	return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
1da177e4 LT	46	}
1da177e4 LT	47
1da177e4	48	static ssize_t
c12c49e7	49	coda_file_write_iter(struct kiocb iocb, struct iov_iter to)
1da177e4	50	{
c12c49e7 AV	51	struct file *coda_file = iocb->ki_filp;
	52	struct inode *coda_inode = file_inode(coda_file);
	53	struct coda_file_info *cfi = CODA_FTOC(coda_file);
1da177e4 LT	54	struct file *host_file;
	55	ssize_t ret;
	56
1da177e4	57	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
1da177e4	58
c12c49e7	59	host_file = cfi->cfi_container;
03d95eb2	60	file_start_write(host_file);
5955102c	61	inode_lock(coda_inode);
abbb6589	62	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
c12c49e7	63	coda_inode->i_size = file_inode(host_file)->i_size;
1da177e4	64	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
02027d42	65	coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);
5955102c	66	inode_unlock(coda_inode);
03d95eb2	67	file_end_write(host_file);
1da177e4 LT	68	return ret;
	69	}
	70
7fa0a1da JH	71	static void
	72	coda_vm_open(struct vm_area_struct *vma)
	73	{
	74	struct coda_vm_ops *cvm_ops =
	75	container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
	76
	77	atomic_inc(&cvm_ops->refcnt);
	78
	79	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open)
	80	cvm_ops->host_vm_ops->open(vma);
	81	}
	82
	83	static void
	84	coda_vm_close(struct vm_area_struct *vma)
	85	{
	86	struct coda_vm_ops *cvm_ops =
	87	container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
	88
	89	if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close)
	90	cvm_ops->host_vm_ops->close(vma);
	91
	92	if (atomic_dec_and_test(&cvm_ops->refcnt)) {
	93	vma->vm_ops = cvm_ops->host_vm_ops;
	94	fput(cvm_ops->coda_file);
	95	kfree(cvm_ops);
	96	}
	97	}
	98
1da177e4 LT	99	static int
	100	coda_file_mmap(struct file coda_file, struct vm_area_struct vma)
	101	{
	102	struct coda_file_info *cfi;
	103	struct coda_inode_info *cii;
	104	struct file *host_file;
	105	struct inode coda_inode, host_inode;
7fa0a1da JH	106	struct coda_vm_ops *cvm_ops;
7fa0a1da JH	107	int ret;
1da177e4 LT	108
	109	cfi = CODA_FTOC(coda_file);
	110	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	111	host_file = cfi->cfi_container;
	112
72c2d531	113	if (!host_file->f_op->mmap)
1da177e4 LT	114	return -ENODEV;
1da177e4 LT	115
7fa0a1da JH	116	if (WARN_ON(coda_file != vma->vm_file))
	117	return -EIO;
	118
	119	cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
	120	if (!cvm_ops)
	121	return -ENOMEM;
	122
496ad9aa AV	123	coda_inode = file_inode(coda_file);
496ad9aa AV	124	host_inode = file_inode(host_file);
b5ce1d83 YA	125
	126	cii = ITOC(coda_inode);
	127	spin_lock(&cii->c_lock);
1da177e4 LT	128	coda_file->f_mapping = host_file->f_mapping;
	129	if (coda_inode->i_mapping == &coda_inode->i_data)
	130	coda_inode->i_mapping = host_inode->i_mapping;
	131
	132	/* only allow additional mmaps as long as userspace isn't changing
	133	* the container file on us! */
b5ce1d83 YA	134	else if (coda_inode->i_mapping != host_inode->i_mapping) {
b5ce1d83 YA	135	spin_unlock(&cii->c_lock);
7fa0a1da	136	kfree(cvm_ops);
1da177e4	137	return -EBUSY;
b5ce1d83	138	}
1da177e4 LT	139
1da177e4 LT	140	/* keep track of how often the coda_inode/host_file has been mmapped */
1da177e4 LT	141	cii->c_mapcount++;
1da177e4 LT	142	cfi->cfi_mapcount++;
b5ce1d83	143	spin_unlock(&cii->c_lock);
1da177e4	144
7fa0a1da JH	145	vma->vm_file = get_file(host_file);
	146	ret = call_mmap(vma->vm_file, vma);
	147
	148	if (ret) {
	149	/* if call_mmap fails, our caller will put coda_file so we
	150	* should drop the reference to the host_file that we got.
	151	*/
	152	fput(host_file);
	153	kfree(cvm_ops);
	154	} else {
	155	/* here we add redirects for the open/close vm_operations */
	156	cvm_ops->host_vm_ops = vma->vm_ops;
	157	if (vma->vm_ops)
	158	cvm_ops->vm_ops = *vma->vm_ops;
	159
	160	cvm_ops->vm_ops.open = coda_vm_open;
	161	cvm_ops->vm_ops.close = coda_vm_close;
	162	cvm_ops->coda_file = coda_file;
	163	atomic_set(&cvm_ops->refcnt, 1);
	164
	165	vma->vm_ops = &cvm_ops->vm_ops;
	166	}
	167	return ret;
1da177e4 LT	168	}
	169
	170	int coda_open(struct inode coda_inode, struct file coda_file)
	171	{
	172	struct file *host_file = NULL;
	173	int error;
	174	unsigned short flags = coda_file->f_flags & (~O_EXCL);
	175	unsigned short coda_flags = coda_flags_to_cflags(flags);
	176	struct coda_file_info *cfi;
	177
1da177e4	178	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
6ecbc4e1	179	if (!cfi)
1da177e4	180	return -ENOMEM;
1da177e4	181
1da177e4	182	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
38c2e437 JH	183	&host_file);
	184	if (!host_file)
	185	error = -EIO;
	186
	187	if (error) {
1da177e4	188	kfree(cfi);
1da177e4 LT	189	return error;
	190	}
	191
	192	host_file->f_flags \|= coda_file->f_flags & (O_APPEND \| O_SYNC);
	193
	194	cfi->cfi_magic = CODA_MAGIC;
	195	cfi->cfi_mapcount = 0;
	196	cfi->cfi_container = host_file;
	197
	198	BUG_ON(coda_file->private_data != NULL);
	199	coda_file->private_data = cfi;
1da177e4 LT	200	return 0;
	201	}
	202
1da177e4 LT	203	int coda_release(struct inode coda_inode, struct file coda_file)
	204	{
	205	unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
	206	unsigned short coda_flags = coda_flags_to_cflags(flags);
	207	struct coda_file_info *cfi;
	208	struct coda_inode_info *cii;
	209	struct inode *host_inode;
f7cc02b8	210	int err;
3cf01f28	211
1da177e4 LT	212	cfi = CODA_FTOC(coda_file);
	213	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	214
d3fec424	215	err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
d76b0d9b	216	coda_flags, coda_file->f_cred->fsuid);
1da177e4	217
496ad9aa	218	host_inode = file_inode(cfi->cfi_container);
1da177e4 LT	219	cii = ITOC(coda_inode);
	220
	221	/* did we mmap this file? */
b5ce1d83	222	spin_lock(&cii->c_lock);
1da177e4 LT	223	if (coda_inode->i_mapping == &host_inode->i_data) {
	224	cii->c_mapcount -= cfi->cfi_mapcount;
	225	if (!cii->c_mapcount)
	226	coda_inode->i_mapping = &coda_inode->i_data;
	227	}
b5ce1d83	228	spin_unlock(&cii->c_lock);
1da177e4 LT	229
	230	fput(cfi->cfi_container);
	231	kfree(coda_file->private_data);
	232	coda_file->private_data = NULL;
	233
d3fec424 JH	234	/* VFS fput ignores the return value from file_operations->release, so
	235	* there is no use returning an error here */
	236	return 0;
1da177e4 LT	237	}
1da177e4 LT	238
02c24a82	239	int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
1da177e4 LT	240	{
1da177e4 LT	241	struct file *host_file;
496ad9aa	242	struct inode *coda_inode = file_inode(coda_file);
1da177e4	243	struct coda_file_info *cfi;
f7cc02b8	244	int err;
1da177e4 LT	245
	246	if (!(S_ISREG(coda_inode->i_mode) \|\| S_ISDIR(coda_inode->i_mode) \|\|
	247	S_ISLNK(coda_inode->i_mode)))
	248	return -EINVAL;
	249
02c24a82 JB	250	err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
	251	if (err)
	252	return err;
5955102c	253	inode_lock(coda_inode);
02c24a82	254
1da177e4 LT	255	cfi = CODA_FTOC(coda_file);
	256	BUG_ON(!cfi \|\| cfi->cfi_magic != CODA_MAGIC);
	257	host_file = cfi->cfi_container;
	258
8018ab05	259	err = vfs_fsync(host_file, datasync);
f7cc02b8	260	if (!err && !datasync)
1da177e4	261	err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
5955102c	262	inode_unlock(coda_inode);
1da177e4 LT	263
	264	return err;
	265	}
	266
4b6f5d20	267	const struct file_operations coda_file_operations = {
1da177e4	268	.llseek = generic_file_llseek,
c12c49e7 AV	269	.read_iter = coda_file_read_iter,
c12c49e7 AV	270	.write_iter = coda_file_write_iter,
1da177e4 LT	271	.mmap = coda_file_mmap,
1da177e4 LT	272	.open = coda_open,
1da177e4 LT	273	.release = coda_release,
1da177e4 LT	274	.fsync = coda_fsync,
82c156f8	275	.splice_read = generic_file_splice_read,
1da177e4	276	};