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v4.17
  1// SPDX-License-Identifier: GPL-2.0
  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>
 17#include <linux/cred.h>
 18#include <linux/errno.h>
 19#include <linux/spinlock.h>
 20#include <linux/string.h>
 21#include <linux/slab.h>
 22#include <linux/uaccess.h>
 
 23
 24#include <linux/coda.h>
 25#include <linux/coda_psdev.h>
 26
 27#include "coda_linux.h"
 28#include "coda_int.h"
 29
 
 
 
 
 
 
 
 30static ssize_t
 31coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 32{
 33	struct file *coda_file = iocb->ki_filp;
 34	struct coda_file_info *cfi = CODA_FTOC(coda_file);
 35
 36	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 
 
 37
 38	return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 39}
 40
 41static ssize_t
 42coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
 43{
 44	struct file *coda_file = iocb->ki_filp;
 45	struct inode *coda_inode = file_inode(coda_file);
 46	struct coda_file_info *cfi = CODA_FTOC(coda_file);
 47	struct file *host_file;
 
 
 48	ssize_t ret;
 49
 50	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 
 
 
 
 51
 52	host_file = cfi->cfi_container;
 53	file_start_write(host_file);
 54	inode_lock(coda_inode);
 55	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
 56	coda_inode->i_size = file_inode(host_file)->i_size;
 57	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
 58	coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);
 59	inode_unlock(coda_inode);
 60	file_end_write(host_file);
 
 
 
 
 
 61	return ret;
 62}
 63
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 64static int
 65coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
 66{
 67	struct coda_file_info *cfi;
 
 
 
 68	struct coda_inode_info *cii;
 69	struct file *host_file;
 70	struct inode *coda_inode, *host_inode;
 71
 72	cfi = CODA_FTOC(coda_file);
 73	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 74	host_file = cfi->cfi_container;
 75
 76	if (!host_file->f_op->mmap)
 77		return -ENODEV;
 78
 79	coda_inode = file_inode(coda_file);
 80	host_inode = file_inode(host_file);
 
 
 
 
 
 
 
 
 
 
 
 
 
 81
 82	cii = ITOC(coda_inode);
 83	spin_lock(&cii->c_lock);
 84	coda_file->f_mapping = host_file->f_mapping;
 85	if (coda_inode->i_mapping == &coda_inode->i_data)
 86		coda_inode->i_mapping = host_inode->i_mapping;
 87
 88	/* only allow additional mmaps as long as userspace isn't changing
 89	 * the container file on us! */
 90	else if (coda_inode->i_mapping != host_inode->i_mapping) {
 91		spin_unlock(&cii->c_lock);
 
 92		return -EBUSY;
 93	}
 94
 95	/* keep track of how often the coda_inode/host_file has been mmapped */
 96	cii->c_mapcount++;
 97	cfi->cfi_mapcount++;
 98	spin_unlock(&cii->c_lock);
 99
100	return call_mmap(host_file, vma);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
101}
102
103int coda_open(struct inode *coda_inode, struct file *coda_file)
104{
105	struct file *host_file = NULL;
106	int error;
107	unsigned short flags = coda_file->f_flags & (~O_EXCL);
108	unsigned short coda_flags = coda_flags_to_cflags(flags);
109	struct coda_file_info *cfi;
110
111	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
112	if (!cfi)
113		return -ENOMEM;
114
115	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
116			   &host_file);
117	if (!host_file)
118		error = -EIO;
119
120	if (error) {
121		kfree(cfi);
122		return error;
123	}
124
125	host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
126
127	cfi->cfi_magic = CODA_MAGIC;
128	cfi->cfi_mapcount = 0;
129	cfi->cfi_container = host_file;
 
 
130
131	BUG_ON(coda_file->private_data != NULL);
132	coda_file->private_data = cfi;
133	return 0;
134}
135
136int coda_release(struct inode *coda_inode, struct file *coda_file)
137{
138	unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
139	unsigned short coda_flags = coda_flags_to_cflags(flags);
140	struct coda_file_info *cfi;
141	struct coda_inode_info *cii;
142	struct inode *host_inode;
143	int err;
144
145	cfi = CODA_FTOC(coda_file);
146	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
147
148	err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
149			  coda_flags, coda_file->f_cred->fsuid);
150
151	host_inode = file_inode(cfi->cfi_container);
152	cii = ITOC(coda_inode);
153
154	/* did we mmap this file? */
155	spin_lock(&cii->c_lock);
156	if (coda_inode->i_mapping == &host_inode->i_data) {
157		cii->c_mapcount -= cfi->cfi_mapcount;
158		if (!cii->c_mapcount)
159			coda_inode->i_mapping = &coda_inode->i_data;
160	}
161	spin_unlock(&cii->c_lock);
162
163	fput(cfi->cfi_container);
164	kfree(coda_file->private_data);
165	coda_file->private_data = NULL;
166
167	/* VFS fput ignores the return value from file_operations->release, so
168	 * there is no use returning an error here */
169	return 0;
170}
171
172int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
173{
174	struct file *host_file;
175	struct inode *coda_inode = file_inode(coda_file);
176	struct coda_file_info *cfi;
177	int err;
178
179	if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
180	      S_ISLNK(coda_inode->i_mode)))
181		return -EINVAL;
182
183	err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
184	if (err)
185		return err;
186	inode_lock(coda_inode);
187
188	cfi = CODA_FTOC(coda_file);
189	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
190	host_file = cfi->cfi_container;
191
192	err = vfs_fsync(host_file, datasync);
193	if (!err && !datasync)
194		err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
195	inode_unlock(coda_inode);
196
197	return err;
198}
199
200const struct file_operations coda_file_operations = {
201	.llseek		= generic_file_llseek,
202	.read_iter	= coda_file_read_iter,
203	.write_iter	= coda_file_write_iter,
204	.mmap		= coda_file_mmap,
205	.open		= coda_open,
206	.release	= coda_release,
207	.fsync		= coda_fsync,
208	.splice_read	= generic_file_splice_read,
209};
210
v5.4
  1// SPDX-License-Identifier: GPL-2.0
  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>
 17#include <linux/cred.h>
 18#include <linux/errno.h>
 19#include <linux/spinlock.h>
 20#include <linux/string.h>
 21#include <linux/slab.h>
 22#include <linux/uaccess.h>
 23#include <linux/uio.h>
 24
 25#include <linux/coda.h>
 26#include "coda_psdev.h"
 
 27#include "coda_linux.h"
 28#include "coda_int.h"
 29
 30struct 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
 37static ssize_t
 38coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 39{
 40	struct file *coda_file = iocb->ki_filp;
 41	struct inode *coda_inode = file_inode(coda_file);
 42	struct coda_file_info *cfi = coda_ftoc(coda_file);
 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);
 54
 55finish_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;
 60}
 61
 62static ssize_t
 63coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
 64{
 65	struct file *coda_file = iocb->ki_filp;
 66	struct inode *coda_inode = file_inode(coda_file);
 67	struct coda_file_info *cfi = coda_ftoc(coda_file);
 68	struct file *host_file = cfi->cfi_container;
 69	loff_t ki_pos = iocb->ki_pos;
 70	size_t count = iov_iter_count(to);
 71	ssize_t ret;
 72
 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
 
 79	file_start_write(host_file);
 80	inode_lock(coda_inode);
 81	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
 82	coda_inode->i_size = file_inode(host_file)->i_size;
 83	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
 84	coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);
 85	inode_unlock(coda_inode);
 86	file_end_write(host_file);
 87
 88finish_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);
 92	return ret;
 93}
 94
 95static void
 96coda_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
107static void
108coda_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
123static int
124coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
125{
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);
130	struct coda_inode_info *cii;
131	struct coda_vm_ops *cvm_ops;
132	loff_t ppos;
133	size_t count;
134	int ret;
 
 
135
136	if (!host_file->f_op->mmap)
137		return -ENODEV;
138
139	if (WARN_ON(coda_file != vma->vm_file))
140		return -EIO;
141
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
151	cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
152	if (!cvm_ops)
153		return -ENOMEM;
154
155	cii = ITOC(coda_inode);
156	spin_lock(&cii->c_lock);
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! */
163	else if (coda_inode->i_mapping != host_inode->i_mapping) {
164		spin_unlock(&cii->c_lock);
165		kfree(cvm_ops);
166		return -EBUSY;
167	}
168
169	/* keep track of how often the coda_inode/host_file has been mmapped */
170	cii->c_mapcount++;
171	cfi->cfi_mapcount++;
172	spin_unlock(&cii->c_lock);
173
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;
197}
198
199int 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
207	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
208	if (!cfi)
209		return -ENOMEM;
210
211	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
212			   &host_file);
213	if (!host_file)
214		error = -EIO;
215
216	if (error) {
217		kfree(cfi);
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;
226	/* assume access intents are supported unless we hear otherwise */
227	cfi->cfi_access_intent = true;
228
229	BUG_ON(coda_file->private_data != NULL);
230	coda_file->private_data = cfi;
231	return 0;
232}
233
234int 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;
241	int err;
242
243	cfi = coda_ftoc(coda_file);
 
244
245	err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
246			  coda_flags, coda_file->f_cred->fsuid);
247
248	host_inode = file_inode(cfi->cfi_container);
249	cii = ITOC(coda_inode);
250
251	/* did we mmap this file? */
252	spin_lock(&cii->c_lock);
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	}
258	spin_unlock(&cii->c_lock);
259
260	fput(cfi->cfi_container);
261	kfree(coda_file->private_data);
262	coda_file->private_data = NULL;
263
264	/* VFS fput ignores the return value from file_operations->release, so
265	 * there is no use returning an error here */
266	return 0;
267}
268
269int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
270{
271	struct file *host_file;
272	struct inode *coda_inode = file_inode(coda_file);
273	struct coda_file_info *cfi;
274	int err;
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
280	err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
281	if (err)
282		return err;
283	inode_lock(coda_inode);
284
285	cfi = coda_ftoc(coda_file);
 
286	host_file = cfi->cfi_container;
287
288	err = vfs_fsync(host_file, datasync);
289	if (!err && !datasync)
290		err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
291	inode_unlock(coda_inode);
292
293	return err;
294}
295
296const struct file_operations coda_file_operations = {
297	.llseek		= generic_file_llseek,
298	.read_iter	= coda_file_read_iter,
299	.write_iter	= coda_file_write_iter,
300	.mmap		= coda_file_mmap,
301	.open		= coda_open,
302	.release	= coda_release,
303	.fsync		= coda_fsync,
304	.splice_read	= generic_file_splice_read,
305};