Daniel Mentz | 94787a1 | 2013-05-29 21:12:04 -0700 | [diff] [blame] | 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, loff_t start, loff_t end, 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 | err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end); |
| 214 | if (err) |
| 215 | return err; |
| 216 | mutex_lock(&coda_inode->i_mutex); |
| 217 | |
| 218 | cfi = CODA_FTOC(coda_file); |
| 219 | BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); |
| 220 | host_file = cfi->cfi_container; |
| 221 | |
| 222 | err = vfs_fsync(host_file, datasync); |
| 223 | if (!err && !datasync) |
| 224 | err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); |
| 225 | mutex_unlock(&coda_inode->i_mutex); |
| 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 | |