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 #include <linux/coda_proc.h> 26 27 #include "coda_int.h" 28 29 /* if CODA_STORE fails with EOPNOTSUPP, venus clearly doesn't support 30 * CODA_STORE/CODA_RELEASE and we fall back on using the CODA_CLOSE upcall */ 31 static int use_coda_close; 32 33 static ssize_t 34 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos) 35 { 36 struct coda_file_info *cfi; 37 struct file *host_file; 38 39 cfi = CODA_FTOC(coda_file); 40 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 41 host_file = cfi->cfi_container; 42 43 if (!host_file->f_op || !host_file->f_op->read) 44 return -EINVAL; 45 46 return host_file->f_op->read(host_file, buf, count, ppos); 47 } 48 49 static ssize_t 50 coda_file_splice_read(struct file *coda_file, loff_t *ppos, 51 struct pipe_inode_info *pipe, size_t count, 52 unsigned int flags) 53 { 54 struct coda_file_info *cfi; 55 struct file *host_file; 56 57 cfi = CODA_FTOC(coda_file); 58 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 59 host_file = cfi->cfi_container; 60 61 if (!host_file->f_op || !host_file->f_op->splice_read) 62 return -EINVAL; 63 64 return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags); 65 } 66 67 static ssize_t 68 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos) 69 { 70 struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode; 71 struct coda_file_info *cfi; 72 struct file *host_file; 73 ssize_t ret; 74 75 cfi = CODA_FTOC(coda_file); 76 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 77 host_file = cfi->cfi_container; 78 79 if (!host_file->f_op || !host_file->f_op->write) 80 return -EINVAL; 81 82 host_inode = host_file->f_path.dentry->d_inode; 83 mutex_lock(&coda_inode->i_mutex); 84 85 ret = host_file->f_op->write(host_file, buf, count, ppos); 86 87 coda_inode->i_size = host_inode->i_size; 88 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9; 89 coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC; 90 mutex_unlock(&coda_inode->i_mutex); 91 92 return ret; 93 } 94 95 static int 96 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) 97 { 98 struct coda_file_info *cfi; 99 struct coda_inode_info *cii; 100 struct file *host_file; 101 struct inode *coda_inode, *host_inode; 102 103 cfi = CODA_FTOC(coda_file); 104 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 105 host_file = cfi->cfi_container; 106 107 if (!host_file->f_op || !host_file->f_op->mmap) 108 return -ENODEV; 109 110 coda_inode = coda_file->f_path.dentry->d_inode; 111 host_inode = host_file->f_path.dentry->d_inode; 112 coda_file->f_mapping = host_file->f_mapping; 113 if (coda_inode->i_mapping == &coda_inode->i_data) 114 coda_inode->i_mapping = host_inode->i_mapping; 115 116 /* only allow additional mmaps as long as userspace isn't changing 117 * the container file on us! */ 118 else if (coda_inode->i_mapping != host_inode->i_mapping) 119 return -EBUSY; 120 121 /* keep track of how often the coda_inode/host_file has been mmapped */ 122 cii = ITOC(coda_inode); 123 cii->c_mapcount++; 124 cfi->cfi_mapcount++; 125 126 return host_file->f_op->mmap(host_file, vma); 127 } 128 129 int coda_open(struct inode *coda_inode, struct file *coda_file) 130 { 131 struct file *host_file = NULL; 132 int error; 133 unsigned short flags = coda_file->f_flags & (~O_EXCL); 134 unsigned short coda_flags = coda_flags_to_cflags(flags); 135 struct coda_file_info *cfi; 136 137 coda_vfs_stat.open++; 138 139 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 140 if (!cfi) 141 return -ENOMEM; 142 143 lock_kernel(); 144 145 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 146 &host_file); 147 if (error || !host_file) { 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 coda_vfs_stat.flush++; 177 178 /* last close semantics */ 179 fcnt = file_count(coda_file); 180 if (fcnt > 1) 181 goto out; 182 183 /* No need to make an upcall when we have not made any modifications 184 * to the file */ 185 if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY) 186 goto out; 187 188 if (use_coda_close) 189 goto out; 190 191 cfi = CODA_FTOC(coda_file); 192 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 193 194 coda_inode = coda_file->f_path.dentry->d_inode; 195 196 err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 197 coda_file->f_uid); 198 199 if (err == -EOPNOTSUPP) { 200 use_coda_close = 1; 201 err = 0; 202 } 203 204 out: 205 unlock_kernel(); 206 return err; 207 } 208 209 int coda_release(struct inode *coda_inode, struct file *coda_file) 210 { 211 unsigned short flags = (coda_file->f_flags) & (~O_EXCL); 212 unsigned short coda_flags = coda_flags_to_cflags(flags); 213 struct coda_file_info *cfi; 214 struct coda_inode_info *cii; 215 struct inode *host_inode; 216 int err = 0; 217 218 lock_kernel(); 219 coda_vfs_stat.release++; 220 221 if (!use_coda_close) { 222 err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode), 223 coda_flags); 224 if (err == -EOPNOTSUPP) { 225 use_coda_close = 1; 226 err = 0; 227 } 228 } 229 230 cfi = CODA_FTOC(coda_file); 231 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 232 233 if (use_coda_close) 234 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 235 coda_flags, coda_file->f_uid); 236 237 host_inode = cfi->cfi_container->f_path.dentry->d_inode; 238 cii = ITOC(coda_inode); 239 240 /* did we mmap this file? */ 241 if (coda_inode->i_mapping == &host_inode->i_data) { 242 cii->c_mapcount -= cfi->cfi_mapcount; 243 if (!cii->c_mapcount) 244 coda_inode->i_mapping = &coda_inode->i_data; 245 } 246 247 fput(cfi->cfi_container); 248 kfree(coda_file->private_data); 249 coda_file->private_data = NULL; 250 251 unlock_kernel(); 252 return err; 253 } 254 255 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync) 256 { 257 struct file *host_file; 258 struct dentry *host_dentry; 259 struct inode *host_inode, *coda_inode = coda_dentry->d_inode; 260 struct coda_file_info *cfi; 261 int err = 0; 262 263 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 264 S_ISLNK(coda_inode->i_mode))) 265 return -EINVAL; 266 267 cfi = CODA_FTOC(coda_file); 268 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 269 host_file = cfi->cfi_container; 270 271 coda_vfs_stat.fsync++; 272 273 if (host_file->f_op && host_file->f_op->fsync) { 274 host_dentry = host_file->f_path.dentry; 275 host_inode = host_dentry->d_inode; 276 mutex_lock(&host_inode->i_mutex); 277 err = host_file->f_op->fsync(host_file, host_dentry, datasync); 278 mutex_unlock(&host_inode->i_mutex); 279 } 280 281 if ( !err && !datasync ) { 282 lock_kernel(); 283 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 284 unlock_kernel(); 285 } 286 287 return err; 288 } 289 290 const struct file_operations coda_file_operations = { 291 .llseek = generic_file_llseek, 292 .read = coda_file_read, 293 .write = coda_file_write, 294 .mmap = coda_file_mmap, 295 .open = coda_open, 296 .flush = coda_flush, 297 .release = coda_release, 298 .fsync = coda_fsync, 299 .splice_read = coda_file_splice_read, 300 }; 301 302