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/spinlock.h> 19 #include <linux/string.h> 20 #include <linux/slab.h> 21 #include <linux/uaccess.h> 22 23 #include <linux/coda.h> 24 #include <linux/coda_psdev.h> 25 26 #include "coda_linux.h" 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->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 ssize_t (*splice_read)(struct file *, loff_t *, 51 struct pipe_inode_info *, size_t, unsigned int); 52 struct coda_file_info *cfi; 53 struct file *host_file; 54 55 cfi = CODA_FTOC(coda_file); 56 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 57 host_file = cfi->cfi_container; 58 59 splice_read = host_file->f_op->splice_read; 60 if (!splice_read) 61 splice_read = default_file_splice_read; 62 63 return 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 = file_inode(coda_file); 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->write) 79 return -EINVAL; 80 81 host_inode = file_inode(host_file); 82 file_start_write(host_file); 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 file_end_write(host_file); 92 93 return ret; 94 } 95 96 static int 97 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) 98 { 99 struct coda_file_info *cfi; 100 struct coda_inode_info *cii; 101 struct file *host_file; 102 struct inode *coda_inode, *host_inode; 103 104 cfi = CODA_FTOC(coda_file); 105 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 106 host_file = cfi->cfi_container; 107 108 if (!host_file->f_op->mmap) 109 return -ENODEV; 110 111 coda_inode = file_inode(coda_file); 112 host_inode = file_inode(host_file); 113 114 cii = ITOC(coda_inode); 115 spin_lock(&cii->c_lock); 116 coda_file->f_mapping = host_file->f_mapping; 117 if (coda_inode->i_mapping == &coda_inode->i_data) 118 coda_inode->i_mapping = host_inode->i_mapping; 119 120 /* only allow additional mmaps as long as userspace isn't changing 121 * the container file on us! */ 122 else if (coda_inode->i_mapping != host_inode->i_mapping) { 123 spin_unlock(&cii->c_lock); 124 return -EBUSY; 125 } 126 127 /* keep track of how often the coda_inode/host_file has been mmapped */ 128 cii->c_mapcount++; 129 cfi->cfi_mapcount++; 130 spin_unlock(&cii->c_lock); 131 132 return host_file->f_op->mmap(host_file, vma); 133 } 134 135 int coda_open(struct inode *coda_inode, struct file *coda_file) 136 { 137 struct file *host_file = NULL; 138 int error; 139 unsigned short flags = coda_file->f_flags & (~O_EXCL); 140 unsigned short coda_flags = coda_flags_to_cflags(flags); 141 struct coda_file_info *cfi; 142 143 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 144 if (!cfi) 145 return -ENOMEM; 146 147 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 148 &host_file); 149 if (!host_file) 150 error = -EIO; 151 152 if (error) { 153 kfree(cfi); 154 return error; 155 } 156 157 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 158 159 cfi->cfi_magic = CODA_MAGIC; 160 cfi->cfi_mapcount = 0; 161 cfi->cfi_container = host_file; 162 163 BUG_ON(coda_file->private_data != NULL); 164 coda_file->private_data = cfi; 165 return 0; 166 } 167 168 int coda_release(struct inode *coda_inode, struct file *coda_file) 169 { 170 unsigned short flags = (coda_file->f_flags) & (~O_EXCL); 171 unsigned short coda_flags = coda_flags_to_cflags(flags); 172 struct coda_file_info *cfi; 173 struct coda_inode_info *cii; 174 struct inode *host_inode; 175 int err; 176 177 cfi = CODA_FTOC(coda_file); 178 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 179 180 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 181 coda_flags, coda_file->f_cred->fsuid); 182 183 host_inode = file_inode(cfi->cfi_container); 184 cii = ITOC(coda_inode); 185 186 /* did we mmap this file? */ 187 spin_lock(&cii->c_lock); 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 spin_unlock(&cii->c_lock); 194 195 fput(cfi->cfi_container); 196 kfree(coda_file->private_data); 197 coda_file->private_data = NULL; 198 199 /* VFS fput ignores the return value from file_operations->release, so 200 * there is no use returning an error here */ 201 return 0; 202 } 203 204 int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync) 205 { 206 struct file *host_file; 207 struct inode *coda_inode = file_inode(coda_file); 208 struct coda_file_info *cfi; 209 int err; 210 211 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 212 S_ISLNK(coda_inode->i_mode))) 213 return -EINVAL; 214 215 err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end); 216 if (err) 217 return err; 218 mutex_lock(&coda_inode->i_mutex); 219 220 cfi = CODA_FTOC(coda_file); 221 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 222 host_file = cfi->cfi_container; 223 224 err = vfs_fsync(host_file, datasync); 225 if (!err && !datasync) 226 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 227 mutex_unlock(&coda_inode->i_mutex); 228 229 return err; 230 } 231 232 const struct file_operations coda_file_operations = { 233 .llseek = generic_file_llseek, 234 .read = coda_file_read, 235 .write = coda_file_write, 236 .mmap = coda_file_mmap, 237 .open = coda_open, 238 .release = coda_release, 239 .fsync = coda_fsync, 240 .splice_read = coda_file_splice_read, 241 }; 242 243