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/refcount.h> 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/time.h> 15 #include <linux/file.h> 16 #include <linux/fs.h> 17 #include <linux/pagemap.h> 18 #include <linux/stat.h> 19 #include <linux/cred.h> 20 #include <linux/errno.h> 21 #include <linux/spinlock.h> 22 #include <linux/string.h> 23 #include <linux/slab.h> 24 #include <linux/uaccess.h> 25 #include <linux/uio.h> 26 #include <linux/splice.h> 27 28 #include <linux/coda.h> 29 #include "coda_psdev.h" 30 #include "coda_linux.h" 31 #include "coda_int.h" 32 33 struct coda_vm_ops { 34 refcount_t refcnt; 35 struct file *coda_file; 36 const struct vm_operations_struct *host_vm_ops; 37 struct vm_operations_struct vm_ops; 38 }; 39 40 static ssize_t 41 coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 42 { 43 struct file *coda_file = iocb->ki_filp; 44 struct inode *coda_inode = file_inode(coda_file); 45 struct coda_file_info *cfi = coda_ftoc(coda_file); 46 loff_t ki_pos = iocb->ki_pos; 47 size_t count = iov_iter_count(to); 48 ssize_t ret; 49 50 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 51 &cfi->cfi_access_intent, 52 count, ki_pos, CODA_ACCESS_TYPE_READ); 53 if (ret) 54 goto finish_read; 55 56 ret = vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0); 57 58 finish_read: 59 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 60 &cfi->cfi_access_intent, 61 count, ki_pos, CODA_ACCESS_TYPE_READ_FINISH); 62 return ret; 63 } 64 65 static ssize_t 66 coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to) 67 { 68 struct file *coda_file = iocb->ki_filp; 69 struct inode *coda_inode = file_inode(coda_file); 70 struct coda_file_info *cfi = coda_ftoc(coda_file); 71 struct file *host_file = cfi->cfi_container; 72 loff_t ki_pos = iocb->ki_pos; 73 size_t count = iov_iter_count(to); 74 ssize_t ret; 75 76 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 77 &cfi->cfi_access_intent, 78 count, ki_pos, CODA_ACCESS_TYPE_WRITE); 79 if (ret) 80 goto finish_write; 81 82 inode_lock(coda_inode); 83 ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0); 84 coda_inode->i_size = file_inode(host_file)->i_size; 85 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9; 86 inode_set_mtime_to_ts(coda_inode, inode_set_ctime_current(coda_inode)); 87 inode_unlock(coda_inode); 88 89 finish_write: 90 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 91 &cfi->cfi_access_intent, 92 count, ki_pos, CODA_ACCESS_TYPE_WRITE_FINISH); 93 return ret; 94 } 95 96 static ssize_t 97 coda_file_splice_read(struct file *coda_file, loff_t *ppos, 98 struct pipe_inode_info *pipe, 99 size_t len, unsigned int flags) 100 { 101 struct inode *coda_inode = file_inode(coda_file); 102 struct coda_file_info *cfi = coda_ftoc(coda_file); 103 struct file *in = cfi->cfi_container; 104 loff_t ki_pos = *ppos; 105 ssize_t ret; 106 107 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 108 &cfi->cfi_access_intent, 109 len, ki_pos, CODA_ACCESS_TYPE_READ); 110 if (ret) 111 goto finish_read; 112 113 ret = vfs_splice_read(in, ppos, pipe, len, flags); 114 115 finish_read: 116 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 117 &cfi->cfi_access_intent, 118 len, ki_pos, CODA_ACCESS_TYPE_READ_FINISH); 119 return ret; 120 } 121 122 static void 123 coda_vm_open(struct vm_area_struct *vma) 124 { 125 struct coda_vm_ops *cvm_ops = 126 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); 127 128 refcount_inc(&cvm_ops->refcnt); 129 130 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open) 131 cvm_ops->host_vm_ops->open(vma); 132 } 133 134 static void 135 coda_vm_close(struct vm_area_struct *vma) 136 { 137 struct coda_vm_ops *cvm_ops = 138 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); 139 140 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close) 141 cvm_ops->host_vm_ops->close(vma); 142 143 if (refcount_dec_and_test(&cvm_ops->refcnt)) { 144 vma->vm_ops = cvm_ops->host_vm_ops; 145 fput(cvm_ops->coda_file); 146 kfree(cvm_ops); 147 } 148 } 149 150 static int 151 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) 152 { 153 struct inode *coda_inode = file_inode(coda_file); 154 struct coda_file_info *cfi = coda_ftoc(coda_file); 155 struct file *host_file = cfi->cfi_container; 156 struct inode *host_inode = file_inode(host_file); 157 struct coda_inode_info *cii; 158 struct coda_vm_ops *cvm_ops; 159 loff_t ppos; 160 size_t count; 161 int ret; 162 163 if (!host_file->f_op->mmap) 164 return -ENODEV; 165 166 if (WARN_ON(coda_file != vma->vm_file)) 167 return -EIO; 168 169 count = vma->vm_end - vma->vm_start; 170 ppos = vma->vm_pgoff * PAGE_SIZE; 171 172 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 173 &cfi->cfi_access_intent, 174 count, ppos, CODA_ACCESS_TYPE_MMAP); 175 if (ret) 176 return ret; 177 178 cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL); 179 if (!cvm_ops) 180 return -ENOMEM; 181 182 cii = ITOC(coda_inode); 183 spin_lock(&cii->c_lock); 184 coda_file->f_mapping = host_file->f_mapping; 185 if (coda_inode->i_mapping == &coda_inode->i_data) 186 coda_inode->i_mapping = host_inode->i_mapping; 187 188 /* only allow additional mmaps as long as userspace isn't changing 189 * the container file on us! */ 190 else if (coda_inode->i_mapping != host_inode->i_mapping) { 191 spin_unlock(&cii->c_lock); 192 kfree(cvm_ops); 193 return -EBUSY; 194 } 195 196 /* keep track of how often the coda_inode/host_file has been mmapped */ 197 cii->c_mapcount++; 198 cfi->cfi_mapcount++; 199 spin_unlock(&cii->c_lock); 200 201 vma->vm_file = get_file(host_file); 202 ret = call_mmap(vma->vm_file, vma); 203 204 if (ret) { 205 /* if call_mmap fails, our caller will put host_file so we 206 * should drop the reference to the coda_file that we got. 207 */ 208 fput(coda_file); 209 kfree(cvm_ops); 210 } else { 211 /* here we add redirects for the open/close vm_operations */ 212 cvm_ops->host_vm_ops = vma->vm_ops; 213 if (vma->vm_ops) 214 cvm_ops->vm_ops = *vma->vm_ops; 215 216 cvm_ops->vm_ops.open = coda_vm_open; 217 cvm_ops->vm_ops.close = coda_vm_close; 218 cvm_ops->coda_file = coda_file; 219 refcount_set(&cvm_ops->refcnt, 1); 220 221 vma->vm_ops = &cvm_ops->vm_ops; 222 } 223 return ret; 224 } 225 226 int coda_open(struct inode *coda_inode, struct file *coda_file) 227 { 228 struct file *host_file = NULL; 229 int error; 230 unsigned short flags = coda_file->f_flags & (~O_EXCL); 231 unsigned short coda_flags = coda_flags_to_cflags(flags); 232 struct coda_file_info *cfi; 233 234 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 235 if (!cfi) 236 return -ENOMEM; 237 238 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 239 &host_file); 240 if (!host_file) 241 error = -EIO; 242 243 if (error) { 244 kfree(cfi); 245 return error; 246 } 247 248 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 249 250 cfi->cfi_magic = CODA_MAGIC; 251 cfi->cfi_mapcount = 0; 252 cfi->cfi_container = host_file; 253 /* assume access intents are supported unless we hear otherwise */ 254 cfi->cfi_access_intent = true; 255 256 BUG_ON(coda_file->private_data != NULL); 257 coda_file->private_data = cfi; 258 return 0; 259 } 260 261 int coda_release(struct inode *coda_inode, struct file *coda_file) 262 { 263 unsigned short flags = (coda_file->f_flags) & (~O_EXCL); 264 unsigned short coda_flags = coda_flags_to_cflags(flags); 265 struct coda_file_info *cfi; 266 struct coda_inode_info *cii; 267 struct inode *host_inode; 268 269 cfi = coda_ftoc(coda_file); 270 271 venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 272 coda_flags, coda_file->f_cred->fsuid); 273 274 host_inode = file_inode(cfi->cfi_container); 275 cii = ITOC(coda_inode); 276 277 /* did we mmap this file? */ 278 spin_lock(&cii->c_lock); 279 if (coda_inode->i_mapping == &host_inode->i_data) { 280 cii->c_mapcount -= cfi->cfi_mapcount; 281 if (!cii->c_mapcount) 282 coda_inode->i_mapping = &coda_inode->i_data; 283 } 284 spin_unlock(&cii->c_lock); 285 286 fput(cfi->cfi_container); 287 kfree(coda_file->private_data); 288 coda_file->private_data = NULL; 289 290 /* VFS fput ignores the return value from file_operations->release, so 291 * there is no use returning an error here */ 292 return 0; 293 } 294 295 int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync) 296 { 297 struct file *host_file; 298 struct inode *coda_inode = file_inode(coda_file); 299 struct coda_file_info *cfi; 300 int err; 301 302 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 303 S_ISLNK(coda_inode->i_mode))) 304 return -EINVAL; 305 306 err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end); 307 if (err) 308 return err; 309 inode_lock(coda_inode); 310 311 cfi = coda_ftoc(coda_file); 312 host_file = cfi->cfi_container; 313 314 err = vfs_fsync(host_file, datasync); 315 if (!err && !datasync) 316 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 317 inode_unlock(coda_inode); 318 319 return err; 320 } 321 322 const struct file_operations coda_file_operations = { 323 .llseek = generic_file_llseek, 324 .read_iter = coda_file_read_iter, 325 .write_iter = coda_file_write_iter, 326 .mmap = coda_file_mmap, 327 .open = coda_open, 328 .release = coda_release, 329 .fsync = coda_fsync, 330 .splice_read = coda_file_splice_read, 331 }; 332