1 /* 2 * linux/fs/9p/vfs_file.c 3 * 4 * This file contians vfs file ops for 9P2000. 5 * 6 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> 7 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 11 * as published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to: 20 * Free Software Foundation 21 * 51 Franklin Street, Fifth Floor 22 * Boston, MA 02111-1301 USA 23 * 24 */ 25 26 #include <linux/module.h> 27 #include <linux/errno.h> 28 #include <linux/fs.h> 29 #include <linux/sched.h> 30 #include <linux/file.h> 31 #include <linux/stat.h> 32 #include <linux/string.h> 33 #include <linux/inet.h> 34 #include <linux/list.h> 35 #include <asm/uaccess.h> 36 #include <linux/idr.h> 37 #include <net/9p/9p.h> 38 #include <net/9p/client.h> 39 40 #include "v9fs.h" 41 #include "v9fs_vfs.h" 42 #include "fid.h" 43 44 static const struct file_operations v9fs_cached_file_operations; 45 46 /** 47 * v9fs_file_open - open a file (or directory) 48 * @inode: inode to be opened 49 * @file: file being opened 50 * 51 */ 52 53 int v9fs_file_open(struct inode *inode, struct file *file) 54 { 55 int err; 56 struct v9fs_session_info *v9ses; 57 struct p9_fid *fid; 58 int omode; 59 60 P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p \n", inode, file); 61 v9ses = v9fs_inode2v9ses(inode); 62 omode = v9fs_uflags2omode(file->f_flags, v9fs_extended(v9ses)); 63 fid = file->private_data; 64 if (!fid) { 65 fid = v9fs_fid_clone(file->f_path.dentry); 66 if (IS_ERR(fid)) 67 return PTR_ERR(fid); 68 69 err = p9_client_open(fid, omode); 70 if (err < 0) { 71 p9_client_clunk(fid); 72 return err; 73 } 74 if (omode & P9_OTRUNC) { 75 inode->i_size = 0; 76 inode->i_blocks = 0; 77 } 78 if ((file->f_flags & O_APPEND) && (!v9fs_extended(v9ses))) 79 generic_file_llseek(file, 0, SEEK_END); 80 } 81 82 file->private_data = fid; 83 if ((fid->qid.version) && (v9ses->cache)) { 84 P9_DPRINTK(P9_DEBUG_VFS, "cached"); 85 /* enable cached file options */ 86 if(file->f_op == &v9fs_file_operations) 87 file->f_op = &v9fs_cached_file_operations; 88 } 89 90 return 0; 91 } 92 93 /** 94 * v9fs_file_lock - lock a file (or directory) 95 * @filp: file to be locked 96 * @cmd: lock command 97 * @fl: file lock structure 98 * 99 * Bugs: this looks like a local only lock, we should extend into 9P 100 * by using open exclusive 101 */ 102 103 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl) 104 { 105 int res = 0; 106 struct inode *inode = filp->f_path.dentry->d_inode; 107 108 P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl); 109 110 /* No mandatory locks */ 111 if (__mandatory_lock(inode)) 112 return -ENOLCK; 113 114 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) { 115 filemap_write_and_wait(inode->i_mapping); 116 invalidate_mapping_pages(&inode->i_data, 0, -1); 117 } 118 119 return res; 120 } 121 122 /** 123 * v9fs_file_readn - read from a file 124 * @filp: file pointer to read 125 * @data: data buffer to read data into 126 * @udata: user data buffer to read data into 127 * @count: size of buffer 128 * @offset: offset at which to read data 129 * 130 */ 131 132 ssize_t 133 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count, 134 u64 offset) 135 { 136 int n, total; 137 struct p9_fid *fid = filp->private_data; 138 139 P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid, 140 (long long unsigned) offset, count); 141 142 n = 0; 143 total = 0; 144 do { 145 n = p9_client_read(fid, data, udata, offset, count); 146 if (n <= 0) 147 break; 148 149 if (data) 150 data += n; 151 if (udata) 152 udata += n; 153 154 offset += n; 155 count -= n; 156 total += n; 157 } while (count > 0 && n == (fid->clnt->msize - P9_IOHDRSZ)); 158 159 if (n < 0) 160 total = n; 161 162 return total; 163 } 164 165 /** 166 * v9fs_file_read - read from a file 167 * @filp: file pointer to read 168 * @udata: user data buffer to read data into 169 * @count: size of buffer 170 * @offset: offset at which to read data 171 * 172 */ 173 174 static ssize_t 175 v9fs_file_read(struct file *filp, char __user *udata, size_t count, 176 loff_t * offset) 177 { 178 int ret; 179 struct p9_fid *fid; 180 181 P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset); 182 fid = filp->private_data; 183 184 if (count > (fid->clnt->msize - P9_IOHDRSZ)) 185 ret = v9fs_file_readn(filp, NULL, udata, count, *offset); 186 else 187 ret = p9_client_read(fid, NULL, udata, *offset, count); 188 189 if (ret > 0) 190 *offset += ret; 191 192 return ret; 193 } 194 195 /** 196 * v9fs_file_write - write to a file 197 * @filp: file pointer to write 198 * @data: data buffer to write data from 199 * @count: size of buffer 200 * @offset: offset at which to write data 201 * 202 */ 203 204 static ssize_t 205 v9fs_file_write(struct file *filp, const char __user * data, 206 size_t count, loff_t * offset) 207 { 208 int n, rsize, total = 0; 209 struct p9_fid *fid; 210 struct p9_client *clnt; 211 struct inode *inode = filp->f_path.dentry->d_inode; 212 int origin = *offset; 213 214 P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data, 215 (int)count, (int)*offset); 216 217 fid = filp->private_data; 218 clnt = fid->clnt; 219 220 rsize = fid->iounit; 221 if (!rsize || rsize > clnt->msize-P9_IOHDRSZ) 222 rsize = clnt->msize - P9_IOHDRSZ; 223 224 do { 225 if (count < rsize) 226 rsize = count; 227 228 n = p9_client_write(fid, NULL, data+total, *offset+total, 229 rsize); 230 if (n <= 0) 231 break; 232 count -= n; 233 total += n; 234 } while (count > 0); 235 236 if (total > 0) { 237 invalidate_inode_pages2_range(inode->i_mapping, origin, 238 origin+total); 239 *offset += total; 240 } 241 242 if (*offset > inode->i_size) { 243 inode->i_size = *offset; 244 inode->i_blocks = (inode->i_size + 512 - 1) >> 9; 245 } 246 247 if (n < 0) 248 return n; 249 250 return total; 251 } 252 253 static const struct file_operations v9fs_cached_file_operations = { 254 .llseek = generic_file_llseek, 255 .read = do_sync_read, 256 .aio_read = generic_file_aio_read, 257 .write = v9fs_file_write, 258 .open = v9fs_file_open, 259 .release = v9fs_dir_release, 260 .lock = v9fs_file_lock, 261 .mmap = generic_file_readonly_mmap, 262 }; 263 264 const struct file_operations v9fs_file_operations = { 265 .llseek = generic_file_llseek, 266 .read = v9fs_file_read, 267 .write = v9fs_file_write, 268 .open = v9fs_file_open, 269 .release = v9fs_dir_release, 270 .lock = v9fs_file_lock, 271 .mmap = generic_file_readonly_mmap, 272 }; 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