1 /* 2 * File operations for Coda. 3 * Original version: (C) 1996 Peter Braam 4 * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University 5 * 6 * Carnegie Mellon encourages users of this code to contribute improvements 7 * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>. 8 */ 9 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/time.h> 13 #include <linux/file.h> 14 #include <linux/fs.h> 15 #include <linux/stat.h> 16 #include <linux/errno.h> 17 #include <linux/smp_lock.h> 18 #include <linux/string.h> 19 #include <asm/uaccess.h> 20 21 #include <linux/coda.h> 22 #include <linux/coda_linux.h> 23 #include <linux/coda_fs_i.h> 24 #include <linux/coda_psdev.h> 25 26 #include "coda_int.h" 27 28 /* if CODA_STORE fails with EOPNOTSUPP, venus clearly doesn't support 29 * CODA_STORE/CODA_RELEASE and we fall back on using the CODA_CLOSE upcall */ 30 static int use_coda_close; 31 32 static ssize_t 33 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos) 34 { 35 struct coda_file_info *cfi; 36 struct file *host_file; 37 38 cfi = CODA_FTOC(coda_file); 39 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 40 host_file = cfi->cfi_container; 41 42 if (!host_file->f_op || !host_file->f_op->read) 43 return -EINVAL; 44 45 return host_file->f_op->read(host_file, buf, count, ppos); 46 } 47 48 static ssize_t 49 coda_file_splice_read(struct file *coda_file, loff_t *ppos, 50 struct pipe_inode_info *pipe, size_t count, 51 unsigned int flags) 52 { 53 struct coda_file_info *cfi; 54 struct file *host_file; 55 56 cfi = CODA_FTOC(coda_file); 57 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 58 host_file = cfi->cfi_container; 59 60 if (!host_file->f_op || !host_file->f_op->splice_read) 61 return -EINVAL; 62 63 return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags); 64 } 65 66 static ssize_t 67 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos) 68 { 69 struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode; 70 struct coda_file_info *cfi; 71 struct file *host_file; 72 ssize_t ret; 73 74 cfi = CODA_FTOC(coda_file); 75 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 76 host_file = cfi->cfi_container; 77 78 if (!host_file->f_op || !host_file->f_op->write) 79 return -EINVAL; 80 81 host_inode = host_file->f_path.dentry->d_inode; 82 mutex_lock(&coda_inode->i_mutex); 83 84 ret = host_file->f_op->write(host_file, buf, count, ppos); 85 86 coda_inode->i_size = host_inode->i_size; 87 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9; 88 coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC; 89 mutex_unlock(&coda_inode->i_mutex); 90 91 return ret; 92 } 93 94 static int 95 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) 96 { 97 struct coda_file_info *cfi; 98 struct coda_inode_info *cii; 99 struct file *host_file; 100 struct inode *coda_inode, *host_inode; 101 102 cfi = CODA_FTOC(coda_file); 103 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 104 host_file = cfi->cfi_container; 105 106 if (!host_file->f_op || !host_file->f_op->mmap) 107 return -ENODEV; 108 109 coda_inode = coda_file->f_path.dentry->d_inode; 110 host_inode = host_file->f_path.dentry->d_inode; 111 coda_file->f_mapping = host_file->f_mapping; 112 if (coda_inode->i_mapping == &coda_inode->i_data) 113 coda_inode->i_mapping = host_inode->i_mapping; 114 115 /* only allow additional mmaps as long as userspace isn't changing 116 * the container file on us! */ 117 else if (coda_inode->i_mapping != host_inode->i_mapping) 118 return -EBUSY; 119 120 /* keep track of how often the coda_inode/host_file has been mmapped */ 121 cii = ITOC(coda_inode); 122 cii->c_mapcount++; 123 cfi->cfi_mapcount++; 124 125 return host_file->f_op->mmap(host_file, vma); 126 } 127 128 int coda_open(struct inode *coda_inode, struct file *coda_file) 129 { 130 struct file *host_file = NULL; 131 int error; 132 unsigned short flags = coda_file->f_flags & (~O_EXCL); 133 unsigned short coda_flags = coda_flags_to_cflags(flags); 134 struct coda_file_info *cfi; 135 136 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 137 if (!cfi) 138 return -ENOMEM; 139 140 lock_kernel(); 141 142 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 143 &host_file); 144 if (!host_file) 145 error = -EIO; 146 147 if (error) { 148 kfree(cfi); 149 unlock_kernel(); 150 return error; 151 } 152 153 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 154 155 cfi->cfi_magic = CODA_MAGIC; 156 cfi->cfi_mapcount = 0; 157 cfi->cfi_container = host_file; 158 159 BUG_ON(coda_file->private_data != NULL); 160 coda_file->private_data = cfi; 161 162 unlock_kernel(); 163 return 0; 164 } 165 166 int coda_flush(struct file *coda_file, fl_owner_t id) 167 { 168 unsigned short flags = coda_file->f_flags & ~O_EXCL; 169 unsigned short coda_flags = coda_flags_to_cflags(flags); 170 struct coda_file_info *cfi; 171 struct inode *coda_inode; 172 int err = 0, fcnt; 173 174 lock_kernel(); 175 176 /* last close semantics */ 177 fcnt = file_count(coda_file); 178 if (fcnt > 1) 179 goto out; 180 181 /* No need to make an upcall when we have not made any modifications 182 * to the file */ 183 if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY) 184 goto out; 185 186 if (use_coda_close) 187 goto out; 188 189 cfi = CODA_FTOC(coda_file); 190 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 191 192 coda_inode = coda_file->f_path.dentry->d_inode; 193 194 err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 195 coda_file->f_uid); 196 197 if (err == -EOPNOTSUPP) { 198 use_coda_close = 1; 199 err = 0; 200 } 201 202 out: 203 unlock_kernel(); 204 return err; 205 } 206 207 int coda_release(struct inode *coda_inode, struct file *coda_file) 208 { 209 unsigned short flags = (coda_file->f_flags) & (~O_EXCL); 210 unsigned short coda_flags = coda_flags_to_cflags(flags); 211 struct coda_file_info *cfi; 212 struct coda_inode_info *cii; 213 struct inode *host_inode; 214 int err = 0; 215 216 lock_kernel(); 217 218 if (!use_coda_close) { 219 err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode), 220 coda_flags); 221 if (err == -EOPNOTSUPP) { 222 use_coda_close = 1; 223 err = 0; 224 } 225 } 226 227 cfi = CODA_FTOC(coda_file); 228 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 229 230 if (use_coda_close) 231 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 232 coda_flags, coda_file->f_uid); 233 234 host_inode = cfi->cfi_container->f_path.dentry->d_inode; 235 cii = ITOC(coda_inode); 236 237 /* did we mmap this file? */ 238 if (coda_inode->i_mapping == &host_inode->i_data) { 239 cii->c_mapcount -= cfi->cfi_mapcount; 240 if (!cii->c_mapcount) 241 coda_inode->i_mapping = &coda_inode->i_data; 242 } 243 244 fput(cfi->cfi_container); 245 kfree(coda_file->private_data); 246 coda_file->private_data = NULL; 247 248 unlock_kernel(); 249 return err; 250 } 251 252 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync) 253 { 254 struct file *host_file; 255 struct dentry *host_dentry; 256 struct inode *host_inode, *coda_inode = coda_dentry->d_inode; 257 struct coda_file_info *cfi; 258 int err = 0; 259 260 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 261 S_ISLNK(coda_inode->i_mode))) 262 return -EINVAL; 263 264 cfi = CODA_FTOC(coda_file); 265 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 266 host_file = cfi->cfi_container; 267 268 if (host_file->f_op && host_file->f_op->fsync) { 269 host_dentry = host_file->f_path.dentry; 270 host_inode = host_dentry->d_inode; 271 mutex_lock(&host_inode->i_mutex); 272 err = host_file->f_op->fsync(host_file, host_dentry, datasync); 273 mutex_unlock(&host_inode->i_mutex); 274 } 275 276 if ( !err && !datasync ) { 277 lock_kernel(); 278 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 279 unlock_kernel(); 280 } 281 282 return err; 283 } 284 285 const struct file_operations coda_file_operations = { 286 .llseek = generic_file_llseek, 287 .read = coda_file_read, 288 .write = coda_file_write, 289 .mmap = coda_file_mmap, 290 .open = coda_open, 291 .flush = coda_flush, 292 .release = coda_release, 293 .fsync = coda_fsync, 294 .splice_read = coda_file_splice_read, 295 }; 296 297