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/stat.h> 18 #include <linux/cred.h> 19 #include <linux/errno.h> 20 #include <linux/spinlock.h> 21 #include <linux/string.h> 22 #include <linux/slab.h> 23 #include <linux/uaccess.h> 24 #include <linux/uio.h> 25 26 #include <linux/coda.h> 27 #include "coda_psdev.h" 28 #include "coda_linux.h" 29 #include "coda_int.h" 30 31 struct coda_vm_ops { 32 refcount_t refcnt; 33 struct file *coda_file; 34 const struct vm_operations_struct *host_vm_ops; 35 struct vm_operations_struct vm_ops; 36 }; 37 38 static ssize_t 39 coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 40 { 41 struct file *coda_file = iocb->ki_filp; 42 struct inode *coda_inode = file_inode(coda_file); 43 struct coda_file_info *cfi = coda_ftoc(coda_file); 44 loff_t ki_pos = iocb->ki_pos; 45 size_t count = iov_iter_count(to); 46 ssize_t ret; 47 48 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 49 &cfi->cfi_access_intent, 50 count, ki_pos, CODA_ACCESS_TYPE_READ); 51 if (ret) 52 goto finish_read; 53 54 ret = vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0); 55 56 finish_read: 57 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 58 &cfi->cfi_access_intent, 59 count, ki_pos, CODA_ACCESS_TYPE_READ_FINISH); 60 return ret; 61 } 62 63 static ssize_t 64 coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to) 65 { 66 struct file *coda_file = iocb->ki_filp; 67 struct inode *coda_inode = file_inode(coda_file); 68 struct coda_file_info *cfi = coda_ftoc(coda_file); 69 struct file *host_file = cfi->cfi_container; 70 loff_t ki_pos = iocb->ki_pos; 71 size_t count = iov_iter_count(to); 72 ssize_t ret; 73 74 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 75 &cfi->cfi_access_intent, 76 count, ki_pos, CODA_ACCESS_TYPE_WRITE); 77 if (ret) 78 goto finish_write; 79 80 file_start_write(host_file); 81 inode_lock(coda_inode); 82 ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0); 83 coda_inode->i_size = file_inode(host_file)->i_size; 84 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9; 85 coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode); 86 inode_unlock(coda_inode); 87 file_end_write(host_file); 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 void 97 coda_vm_open(struct vm_area_struct *vma) 98 { 99 struct coda_vm_ops *cvm_ops = 100 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); 101 102 refcount_inc(&cvm_ops->refcnt); 103 104 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open) 105 cvm_ops->host_vm_ops->open(vma); 106 } 107 108 static void 109 coda_vm_close(struct vm_area_struct *vma) 110 { 111 struct coda_vm_ops *cvm_ops = 112 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); 113 114 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close) 115 cvm_ops->host_vm_ops->close(vma); 116 117 if (refcount_dec_and_test(&cvm_ops->refcnt)) { 118 vma->vm_ops = cvm_ops->host_vm_ops; 119 fput(cvm_ops->coda_file); 120 kfree(cvm_ops); 121 } 122 } 123 124 static int 125 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) 126 { 127 struct inode *coda_inode = file_inode(coda_file); 128 struct coda_file_info *cfi = coda_ftoc(coda_file); 129 struct file *host_file = cfi->cfi_container; 130 struct inode *host_inode = file_inode(host_file); 131 struct coda_inode_info *cii; 132 struct coda_vm_ops *cvm_ops; 133 loff_t ppos; 134 size_t count; 135 int ret; 136 137 if (!host_file->f_op->mmap) 138 return -ENODEV; 139 140 if (WARN_ON(coda_file != vma->vm_file)) 141 return -EIO; 142 143 count = vma->vm_end - vma->vm_start; 144 ppos = vma->vm_pgoff * PAGE_SIZE; 145 146 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode), 147 &cfi->cfi_access_intent, 148 count, ppos, CODA_ACCESS_TYPE_MMAP); 149 if (ret) 150 return ret; 151 152 cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL); 153 if (!cvm_ops) 154 return -ENOMEM; 155 156 cii = ITOC(coda_inode); 157 spin_lock(&cii->c_lock); 158 coda_file->f_mapping = host_file->f_mapping; 159 if (coda_inode->i_mapping == &coda_inode->i_data) 160 coda_inode->i_mapping = host_inode->i_mapping; 161 162 /* only allow additional mmaps as long as userspace isn't changing 163 * the container file on us! */ 164 else if (coda_inode->i_mapping != host_inode->i_mapping) { 165 spin_unlock(&cii->c_lock); 166 kfree(cvm_ops); 167 return -EBUSY; 168 } 169 170 /* keep track of how often the coda_inode/host_file has been mmapped */ 171 cii->c_mapcount++; 172 cfi->cfi_mapcount++; 173 spin_unlock(&cii->c_lock); 174 175 vma->vm_file = get_file(host_file); 176 ret = call_mmap(vma->vm_file, vma); 177 178 if (ret) { 179 /* if call_mmap fails, our caller will put host_file so we 180 * should drop the reference to the coda_file that we got. 181 */ 182 fput(coda_file); 183 kfree(cvm_ops); 184 } else { 185 /* here we add redirects for the open/close vm_operations */ 186 cvm_ops->host_vm_ops = vma->vm_ops; 187 if (vma->vm_ops) 188 cvm_ops->vm_ops = *vma->vm_ops; 189 190 cvm_ops->vm_ops.open = coda_vm_open; 191 cvm_ops->vm_ops.close = coda_vm_close; 192 cvm_ops->coda_file = coda_file; 193 refcount_set(&cvm_ops->refcnt, 1); 194 195 vma->vm_ops = &cvm_ops->vm_ops; 196 } 197 return ret; 198 } 199 200 int coda_open(struct inode *coda_inode, struct file *coda_file) 201 { 202 struct file *host_file = NULL; 203 int error; 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; 207 208 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 209 if (!cfi) 210 return -ENOMEM; 211 212 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 213 &host_file); 214 if (!host_file) 215 error = -EIO; 216 217 if (error) { 218 kfree(cfi); 219 return error; 220 } 221 222 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 223 224 cfi->cfi_magic = CODA_MAGIC; 225 cfi->cfi_mapcount = 0; 226 cfi->cfi_container = host_file; 227 /* assume access intents are supported unless we hear otherwise */ 228 cfi->cfi_access_intent = true; 229 230 BUG_ON(coda_file->private_data != NULL); 231 coda_file->private_data = cfi; 232 return 0; 233 } 234 235 int coda_release(struct inode *coda_inode, struct file *coda_file) 236 { 237 unsigned short flags = (coda_file->f_flags) & (~O_EXCL); 238 unsigned short coda_flags = coda_flags_to_cflags(flags); 239 struct coda_file_info *cfi; 240 struct coda_inode_info *cii; 241 struct inode *host_inode; 242 243 cfi = coda_ftoc(coda_file); 244 245 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 } 268 269 int 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 } 295 296 const 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 }; 306