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 <linux/slab.h> 21 #include <asm/uaccess.h> 22 23 #include <linux/coda.h> 24 #include <linux/coda_linux.h> 25 #include <linux/coda_fs_i.h> 26 #include <linux/coda_psdev.h> 27 28 #include "coda_int.h" 29 30 static ssize_t 31 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos) 32 { 33 struct coda_file_info *cfi; 34 struct file *host_file; 35 36 cfi = CODA_FTOC(coda_file); 37 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 38 host_file = cfi->cfi_container; 39 40 if (!host_file->f_op || !host_file->f_op->read) 41 return -EINVAL; 42 43 return host_file->f_op->read(host_file, buf, count, ppos); 44 } 45 46 static ssize_t 47 coda_file_splice_read(struct file *coda_file, loff_t *ppos, 48 struct pipe_inode_info *pipe, size_t count, 49 unsigned int flags) 50 { 51 ssize_t (*splice_read)(struct file *, loff_t *, 52 struct pipe_inode_info *, size_t, unsigned int); 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 splice_read = host_file->f_op->splice_read; 61 if (!splice_read) 62 splice_read = default_file_splice_read; 63 64 return 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 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 138 if (!cfi) 139 return -ENOMEM; 140 141 lock_kernel(); 142 143 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 144 &host_file); 145 if (!host_file) 146 error = -EIO; 147 148 if (error) { 149 kfree(cfi); 150 unlock_kernel(); 151 return error; 152 } 153 154 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 155 156 cfi->cfi_magic = CODA_MAGIC; 157 cfi->cfi_mapcount = 0; 158 cfi->cfi_container = host_file; 159 160 BUG_ON(coda_file->private_data != NULL); 161 coda_file->private_data = cfi; 162 163 unlock_kernel(); 164 return 0; 165 } 166 167 int coda_release(struct inode *coda_inode, struct file *coda_file) 168 { 169 unsigned short flags = (coda_file->f_flags) & (~O_EXCL); 170 unsigned short coda_flags = coda_flags_to_cflags(flags); 171 struct coda_file_info *cfi; 172 struct coda_inode_info *cii; 173 struct inode *host_inode; 174 int err = 0; 175 176 lock_kernel(); 177 178 cfi = CODA_FTOC(coda_file); 179 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 180 181 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 182 coda_flags, coda_file->f_cred->fsuid); 183 184 host_inode = cfi->cfi_container->f_path.dentry->d_inode; 185 cii = ITOC(coda_inode); 186 187 /* did we mmap this file? */ 188 if (coda_inode->i_mapping == &host_inode->i_data) { 189 cii->c_mapcount -= cfi->cfi_mapcount; 190 if (!cii->c_mapcount) 191 coda_inode->i_mapping = &coda_inode->i_data; 192 } 193 194 fput(cfi->cfi_container); 195 kfree(coda_file->private_data); 196 coda_file->private_data = NULL; 197 198 unlock_kernel(); 199 200 /* VFS fput ignores the return value from file_operations->release, so 201 * there is no use returning an error here */ 202 return 0; 203 } 204 205 int coda_fsync(struct file *coda_file, int datasync) 206 { 207 struct file *host_file; 208 struct inode *coda_inode = coda_file->f_path.dentry->d_inode; 209 struct coda_file_info *cfi; 210 int err = 0; 211 212 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 213 S_ISLNK(coda_inode->i_mode))) 214 return -EINVAL; 215 216 cfi = CODA_FTOC(coda_file); 217 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 218 host_file = cfi->cfi_container; 219 220 err = vfs_fsync(host_file, datasync); 221 if ( !err && !datasync ) { 222 lock_kernel(); 223 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 224 unlock_kernel(); 225 } 226 227 return err; 228 } 229 230 const struct file_operations coda_file_operations = { 231 .llseek = generic_file_llseek, 232 .read = coda_file_read, 233 .write = coda_file_write, 234 .mmap = coda_file_mmap, 235 .open = coda_open, 236 .release = coda_release, 237 .fsync = coda_fsync, 238 .splice_read = coda_file_splice_read, 239 }; 240 241