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/cred.h> 17 #include <linux/errno.h> 18 #include <linux/smp_lock.h> 19 #include <linux/string.h> 20 #include <asm/uaccess.h> 21 22 #include <linux/coda.h> 23 #include <linux/coda_linux.h> 24 #include <linux/coda_fs_i.h> 25 #include <linux/coda_psdev.h> 26 27 #include "coda_int.h" 28 29 static ssize_t 30 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos) 31 { 32 struct coda_file_info *cfi; 33 struct file *host_file; 34 35 cfi = CODA_FTOC(coda_file); 36 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 37 host_file = cfi->cfi_container; 38 39 if (!host_file->f_op || !host_file->f_op->read) 40 return -EINVAL; 41 42 return host_file->f_op->read(host_file, buf, count, ppos); 43 } 44 45 static ssize_t 46 coda_file_splice_read(struct file *coda_file, loff_t *ppos, 47 struct pipe_inode_info *pipe, size_t count, 48 unsigned int flags) 49 { 50 struct coda_file_info *cfi; 51 struct file *host_file; 52 53 cfi = CODA_FTOC(coda_file); 54 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 55 host_file = cfi->cfi_container; 56 57 if (!host_file->f_op || !host_file->f_op->splice_read) 58 return -EINVAL; 59 60 return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags); 61 } 62 63 static ssize_t 64 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos) 65 { 66 struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode; 67 struct coda_file_info *cfi; 68 struct file *host_file; 69 ssize_t ret; 70 71 cfi = CODA_FTOC(coda_file); 72 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 73 host_file = cfi->cfi_container; 74 75 if (!host_file->f_op || !host_file->f_op->write) 76 return -EINVAL; 77 78 host_inode = host_file->f_path.dentry->d_inode; 79 mutex_lock(&coda_inode->i_mutex); 80 81 ret = host_file->f_op->write(host_file, buf, count, ppos); 82 83 coda_inode->i_size = host_inode->i_size; 84 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9; 85 coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC; 86 mutex_unlock(&coda_inode->i_mutex); 87 88 return ret; 89 } 90 91 static int 92 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) 93 { 94 struct coda_file_info *cfi; 95 struct coda_inode_info *cii; 96 struct file *host_file; 97 struct inode *coda_inode, *host_inode; 98 99 cfi = CODA_FTOC(coda_file); 100 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 101 host_file = cfi->cfi_container; 102 103 if (!host_file->f_op || !host_file->f_op->mmap) 104 return -ENODEV; 105 106 coda_inode = coda_file->f_path.dentry->d_inode; 107 host_inode = host_file->f_path.dentry->d_inode; 108 coda_file->f_mapping = host_file->f_mapping; 109 if (coda_inode->i_mapping == &coda_inode->i_data) 110 coda_inode->i_mapping = host_inode->i_mapping; 111 112 /* only allow additional mmaps as long as userspace isn't changing 113 * the container file on us! */ 114 else if (coda_inode->i_mapping != host_inode->i_mapping) 115 return -EBUSY; 116 117 /* keep track of how often the coda_inode/host_file has been mmapped */ 118 cii = ITOC(coda_inode); 119 cii->c_mapcount++; 120 cfi->cfi_mapcount++; 121 122 return host_file->f_op->mmap(host_file, vma); 123 } 124 125 int coda_open(struct inode *coda_inode, struct file *coda_file) 126 { 127 struct file *host_file = NULL; 128 int error; 129 unsigned short flags = coda_file->f_flags & (~O_EXCL); 130 unsigned short coda_flags = coda_flags_to_cflags(flags); 131 struct coda_file_info *cfi; 132 133 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 134 if (!cfi) 135 return -ENOMEM; 136 137 lock_kernel(); 138 139 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 140 &host_file); 141 if (!host_file) 142 error = -EIO; 143 144 if (error) { 145 kfree(cfi); 146 unlock_kernel(); 147 return error; 148 } 149 150 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 151 152 cfi->cfi_magic = CODA_MAGIC; 153 cfi->cfi_mapcount = 0; 154 cfi->cfi_container = host_file; 155 156 BUG_ON(coda_file->private_data != NULL); 157 coda_file->private_data = cfi; 158 159 unlock_kernel(); 160 return 0; 161 } 162 163 int coda_release(struct inode *coda_inode, struct file *coda_file) 164 { 165 unsigned short flags = (coda_file->f_flags) & (~O_EXCL); 166 unsigned short coda_flags = coda_flags_to_cflags(flags); 167 struct coda_file_info *cfi; 168 struct coda_inode_info *cii; 169 struct inode *host_inode; 170 int err = 0; 171 172 lock_kernel(); 173 174 cfi = CODA_FTOC(coda_file); 175 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 176 177 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 178 coda_flags, coda_file->f_cred->fsuid); 179 180 host_inode = cfi->cfi_container->f_path.dentry->d_inode; 181 cii = ITOC(coda_inode); 182 183 /* did we mmap this file? */ 184 if (coda_inode->i_mapping == &host_inode->i_data) { 185 cii->c_mapcount -= cfi->cfi_mapcount; 186 if (!cii->c_mapcount) 187 coda_inode->i_mapping = &coda_inode->i_data; 188 } 189 190 fput(cfi->cfi_container); 191 kfree(coda_file->private_data); 192 coda_file->private_data = NULL; 193 194 unlock_kernel(); 195 196 /* VFS fput ignores the return value from file_operations->release, so 197 * there is no use returning an error here */ 198 return 0; 199 } 200 201 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync) 202 { 203 struct file *host_file; 204 struct inode *coda_inode = coda_dentry->d_inode; 205 struct coda_file_info *cfi; 206 int err = 0; 207 208 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 209 S_ISLNK(coda_inode->i_mode))) 210 return -EINVAL; 211 212 cfi = CODA_FTOC(coda_file); 213 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 214 host_file = cfi->cfi_container; 215 216 err = vfs_fsync(host_file, host_file->f_path.dentry, datasync); 217 if ( !err && !datasync ) { 218 lock_kernel(); 219 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 220 unlock_kernel(); 221 } 222 223 return err; 224 } 225 226 const struct file_operations coda_file_operations = { 227 .llseek = generic_file_llseek, 228 .read = coda_file_read, 229 .write = coda_file_write, 230 .mmap = coda_file_mmap, 231 .open = coda_open, 232 .release = coda_release, 233 .fsync = coda_fsync, 234 .splice_read = coda_file_splice_read, 235 }; 236 237