1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This file contains vfs directory ops for the 9P2000 protocol. 4 * 5 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> 6 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 7 */ 8 9 #include <linux/module.h> 10 #include <linux/errno.h> 11 #include <linux/fs.h> 12 #include <linux/file.h> 13 #include <linux/stat.h> 14 #include <linux/string.h> 15 #include <linux/sched.h> 16 #include <linux/slab.h> 17 #include <linux/uio.h> 18 #include <linux/fscache.h> 19 #include <net/9p/9p.h> 20 #include <net/9p/client.h> 21 22 #include "v9fs.h" 23 #include "v9fs_vfs.h" 24 #include "fid.h" 25 26 /** 27 * struct p9_rdir - readdir accounting 28 * @head: start offset of current dirread buffer 29 * @tail: end offset of current dirread buffer 30 * @offset: file position the data at @head corresponds to 31 * @buf: dirread buffer 32 * 33 * private structure for keeping track of readdir 34 * allocated on demand 35 */ 36 37 struct p9_rdir { 38 int head; 39 int tail; 40 loff_t offset; 41 uint8_t buf[]; 42 }; 43 44 /** 45 * dt_type - return file type 46 * @mistat: mistat structure 47 * 48 */ 49 50 static inline int dt_type(struct p9_wstat *mistat) 51 { 52 unsigned long perm = mistat->mode; 53 int rettype = DT_REG; 54 55 if (perm & P9_DMDIR) 56 rettype = DT_DIR; 57 if (perm & P9_DMSYMLINK) 58 rettype = DT_LNK; 59 60 return rettype; 61 } 62 63 /** 64 * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir 65 * @filp: opened file structure 66 * @buflen: Length in bytes of buffer to allocate 67 * 68 */ 69 70 static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen) 71 { 72 struct p9_fid *fid = filp->private_data; 73 74 if (!fid->rdir) 75 fid->rdir = kvzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL); 76 return fid->rdir; 77 } 78 79 /** 80 * v9fs_dir_readdir - iterate through a directory 81 * @file: opened file structure 82 * @ctx: actor we feed the entries to 83 * 84 */ 85 86 static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx) 87 { 88 bool over; 89 struct p9_wstat st; 90 int err = 0; 91 struct p9_fid *fid; 92 int buflen; 93 struct p9_rdir *rdir; 94 struct kvec kvec; 95 96 p9_debug(P9_DEBUG_VFS, "name %pD\n", file); 97 fid = file->private_data; 98 99 buflen = fid->clnt->msize - P9_IOHDRSZ; 100 101 rdir = v9fs_alloc_rdir_buf(file, buflen); 102 if (!rdir) 103 return -ENOMEM; 104 kvec.iov_base = rdir->buf; 105 kvec.iov_len = buflen; 106 107 if (rdir->head < rdir->tail && rdir->offset != ctx->pos) 108 rdir->head = rdir->tail = 0; 109 110 while (1) { 111 if (rdir->tail == rdir->head) { 112 struct iov_iter to; 113 int n; 114 115 iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buflen); 116 n = p9_client_read(file->private_data, ctx->pos, &to, 117 &err); 118 if (err) 119 return err; 120 if (n == 0) 121 return 0; 122 123 rdir->head = 0; 124 rdir->tail = n; 125 rdir->offset = ctx->pos; 126 } 127 while (rdir->head < rdir->tail) { 128 err = p9stat_read(fid->clnt, rdir->buf + rdir->head, 129 rdir->tail - rdir->head, &st); 130 if (err <= 0) { 131 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 132 return -EIO; 133 } 134 135 over = !dir_emit(ctx, st.name, strlen(st.name), 136 QID2INO(&st.qid), dt_type(&st)); 137 p9stat_free(&st); 138 if (over) 139 return 0; 140 141 rdir->head += err; 142 ctx->pos += err; 143 rdir->offset = ctx->pos; 144 } 145 } 146 } 147 148 /** 149 * v9fs_dir_readdir_dotl - iterate through a directory 150 * @file: opened file structure 151 * @ctx: actor we feed the entries to 152 * 153 */ 154 static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx) 155 { 156 int err = 0; 157 struct p9_fid *fid; 158 int buflen; 159 struct p9_rdir *rdir; 160 struct p9_dirent curdirent; 161 162 p9_debug(P9_DEBUG_VFS, "name %pD\n", file); 163 fid = file->private_data; 164 165 buflen = fid->clnt->msize - P9_READDIRHDRSZ; 166 167 rdir = v9fs_alloc_rdir_buf(file, buflen); 168 if (!rdir) 169 return -ENOMEM; 170 171 if (rdir->head < rdir->tail && rdir->offset != ctx->pos) 172 rdir->head = rdir->tail = 0; 173 174 while (1) { 175 if (rdir->tail == rdir->head) { 176 err = p9_client_readdir(fid, rdir->buf, buflen, 177 ctx->pos); 178 if (err <= 0) 179 return err; 180 181 rdir->head = 0; 182 rdir->tail = err; 183 rdir->offset = ctx->pos; 184 } 185 186 while (rdir->head < rdir->tail) { 187 188 err = p9dirent_read(fid->clnt, rdir->buf + rdir->head, 189 rdir->tail - rdir->head, 190 &curdirent); 191 if (err < 0) { 192 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 193 return -EIO; 194 } 195 196 if (!dir_emit(ctx, curdirent.d_name, 197 strlen(curdirent.d_name), 198 QID2INO(&curdirent.qid), 199 curdirent.d_type)) 200 return 0; 201 202 ctx->pos = curdirent.d_off; 203 rdir->head += err; 204 rdir->offset = ctx->pos; 205 } 206 } 207 } 208 209 210 /** 211 * v9fs_dir_release - close a directory or a file 212 * @inode: inode of the directory or file 213 * @filp: file pointer to a directory or file 214 * 215 */ 216 217 int v9fs_dir_release(struct inode *inode, struct file *filp) 218 { 219 struct v9fs_inode *v9inode = V9FS_I(inode); 220 struct p9_fid *fid; 221 __le32 version; 222 loff_t i_size; 223 int retval = 0, put_err; 224 225 fid = filp->private_data; 226 p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n", 227 inode, filp, fid ? fid->fid : -1); 228 229 if (fid) { 230 if ((S_ISREG(inode->i_mode)) && (filp->f_mode & FMODE_WRITE)) 231 retval = filemap_fdatawrite(inode->i_mapping); 232 233 spin_lock(&inode->i_lock); 234 hlist_del(&fid->ilist); 235 spin_unlock(&inode->i_lock); 236 put_err = p9_fid_put(fid); 237 retval = retval < 0 ? retval : put_err; 238 } 239 240 if ((filp->f_mode & FMODE_WRITE)) { 241 version = cpu_to_le32(v9inode->qid.version); 242 i_size = i_size_read(inode); 243 fscache_unuse_cookie(v9fs_inode_cookie(v9inode), 244 &version, &i_size); 245 } else { 246 fscache_unuse_cookie(v9fs_inode_cookie(v9inode), NULL, NULL); 247 } 248 return retval; 249 } 250 251 const struct file_operations v9fs_dir_operations = { 252 .read = generic_read_dir, 253 .llseek = generic_file_llseek, 254 .iterate_shared = v9fs_dir_readdir, 255 .open = v9fs_file_open, 256 .release = v9fs_dir_release, 257 }; 258 259 const struct file_operations v9fs_dir_operations_dotl = { 260 .read = generic_read_dir, 261 .llseek = generic_file_llseek, 262 .iterate_shared = v9fs_dir_readdir_dotl, 263 .open = v9fs_file_open, 264 .release = v9fs_dir_release, 265 .fsync = v9fs_file_fsync_dotl, 266 }; 267