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_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; 112 113 cii = ITOC(coda_inode); 114 spin_lock(&cii->c_lock); 115 coda_file->f_mapping = host_file->f_mapping; 116 if (coda_inode->i_mapping == &coda_inode->i_data) 117 coda_inode->i_mapping = host_inode->i_mapping; 118 119 /* only allow additional mmaps as long as userspace isn't changing 120 * the container file on us! */ 121 else if (coda_inode->i_mapping != host_inode->i_mapping) { 122 spin_unlock(&cii->c_lock); 123 return -EBUSY; 124 } 125 126 /* keep track of how often the coda_inode/host_file has been mmapped */ 127 cii->c_mapcount++; 128 cfi->cfi_mapcount++; 129 spin_unlock(&cii->c_lock); 130 131 return host_file->f_op->mmap(host_file, vma); 132 } 133 134 int coda_open(struct inode *coda_inode, struct file *coda_file) 135 { 136 struct file *host_file = NULL; 137 int error; 138 unsigned short flags = coda_file->f_flags & (~O_EXCL); 139 unsigned short coda_flags = coda_flags_to_cflags(flags); 140 struct coda_file_info *cfi; 141 142 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); 143 if (!cfi) 144 return -ENOMEM; 145 146 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, 147 &host_file); 148 if (!host_file) 149 error = -EIO; 150 151 if (error) { 152 kfree(cfi); 153 return error; 154 } 155 156 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); 157 158 cfi->cfi_magic = CODA_MAGIC; 159 cfi->cfi_mapcount = 0; 160 cfi->cfi_container = host_file; 161 162 BUG_ON(coda_file->private_data != NULL); 163 coda_file->private_data = cfi; 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; 175 176 cfi = CODA_FTOC(coda_file); 177 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 178 179 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), 180 coda_flags, coda_file->f_cred->fsuid); 181 182 host_inode = cfi->cfi_container->f_path.dentry->d_inode; 183 cii = ITOC(coda_inode); 184 185 /* did we mmap this file? */ 186 spin_lock(&cii->c_lock); 187 if (coda_inode->i_mapping == &host_inode->i_data) { 188 cii->c_mapcount -= cfi->cfi_mapcount; 189 if (!cii->c_mapcount) 190 coda_inode->i_mapping = &coda_inode->i_data; 191 } 192 spin_unlock(&cii->c_lock); 193 194 fput(cfi->cfi_container); 195 kfree(coda_file->private_data); 196 coda_file->private_data = NULL; 197 198 /* VFS fput ignores the return value from file_operations->release, so 199 * there is no use returning an error here */ 200 return 0; 201 } 202 203 int coda_fsync(struct file *coda_file, int datasync) 204 { 205 struct file *host_file; 206 struct inode *coda_inode = coda_file->f_path.dentry->d_inode; 207 struct coda_file_info *cfi; 208 int err; 209 210 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || 211 S_ISLNK(coda_inode->i_mode))) 212 return -EINVAL; 213 214 cfi = CODA_FTOC(coda_file); 215 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); 216 host_file = cfi->cfi_container; 217 218 err = vfs_fsync(host_file, datasync); 219 if (!err && !datasync) 220 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); 221 222 return err; 223 } 224 225 const struct file_operations coda_file_operations = { 226 .llseek = generic_file_llseek, 227 .read = coda_file_read, 228 .write = coda_file_write, 229 .mmap = coda_file_mmap, 230 .open = coda_open, 231 .release = coda_release, 232 .fsync = coda_fsync, 233 .splice_read = coda_file_splice_read, 234 }; 235 236