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 <asm/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 || !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 = 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; 111 112 cii = ITOC(coda_inode); 113 spin_lock(&cii->c_lock); 114 coda_file->f_mapping = host_file->f_mapping; 115 if (coda_inode->i_mapping == &coda_inode->i_data) 116 coda_inode->i_mapping = host_inode->i_mapping; 117 118 /* only allow additional mmaps as long as userspace isn't changing 119 * the container file on us! */ 120 else if (coda_inode->i_mapping != host_inode->i_mapping) { 121 spin_unlock(&cii->c_lock); 122 return -EBUSY; 123 } 124 125 /* keep track of how often the coda_inode/host_file has been mmapped */ 126 cii->c_mapcount++; 127 cfi->cfi_mapcount++; 128 spin_unlock(&cii->c_lock); 129 130 return host_file->f_op->mmap(host_file, vma); 131 } 132 133 int coda_open(struct inode *coda_inode, struct file *coda_file) 134 { 135 struct file *host_file = NULL; 136 int error; 137 unsigned short flags = coda_file->f_flags & (~O_EXCL); 138 unsigned short coda_flags = coda_flags_to_cflags(flags); 139 struct coda_file_info *cfi; 140 141 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 142 if (!cfi) 143 return -ENOMEM; 144 145 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 146 &host_file); 147 if (!host_file) 148 error = -EIO; 149 150 if (error) { 151 kfree(cfi); 152 return error; 153 } 154 155 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 156 157 cfi->cfi_magic = CODA_MAGIC; 158 cfi->cfi_mapcount = 0; 159 cfi->cfi_container = host_file; 160 161 BUG_ON(coda_file->private_data != NULL); 162 coda_file->private_data = cfi; 163 return 0; 164 } 165 166 int coda_release(struct inode *coda_inode, struct file *coda_file) 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 coda_inode_info *cii; 172 struct inode *host_inode; 173 int err; 174 175 cfi = CODA_FTOC(coda_file); 176 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 177 178 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 179 coda_flags, coda_file->f_cred->fsuid); 180 181 host_inode = cfi->cfi_container->f_path.dentry->d_inode; 182 cii = ITOC(coda_inode); 183 184 /* did we mmap this file? */ 185 spin_lock(&cii->c_lock); 186 if (coda_inode->i_mapping == &host_inode->i_data) { 187 cii->c_mapcount -= cfi->cfi_mapcount; 188 if (!cii->c_mapcount) 189 coda_inode->i_mapping = &coda_inode->i_data; 190 } 191 spin_unlock(&cii->c_lock); 192 193 fput(cfi->cfi_container); 194 kfree(coda_file->private_data); 195 coda_file->private_data = NULL; 196 197 /* VFS fput ignores the return value from file_operations->release, so 198 * there is no use returning an error here */ 199 return 0; 200 } 201 202 int coda_fsync(struct file *coda_file, int datasync) 203 { 204 struct file *host_file; 205 struct inode *coda_inode = coda_file->f_path.dentry->d_inode; 206 struct coda_file_info *cfi; 207 int err; 208 209 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 210 S_ISLNK(coda_inode->i_mode))) 211 return -EINVAL; 212 213 cfi = CODA_FTOC(coda_file); 214 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 215 host_file = cfi->cfi_container; 216 217 err = vfs_fsync(host_file, datasync); 218 if (!err && !datasync) 219 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 220 221 return err; 222 } 223 224 const struct file_operations coda_file_operations = { 225 .llseek = generic_file_llseek, 226 .read = coda_file_read, 227 .write = coda_file_write, 228 .mmap = coda_file_mmap, 229 .open = coda_open, 230 .release = coda_release, 231 .fsync = coda_fsync, 232 .splice_read = coda_file_splice_read, 233 }; 234 235