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