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/inet.h> 17 #include <linux/idr.h> 18 #include <linux/slab.h> 19 #include <linux/uio.h> 20 #include <linux/fscache.h> 21 #include <net/9p/9p.h> 22 #include <net/9p/client.h> 23 24 #include "v9fs.h" 25 #include "v9fs_vfs.h" 26 #include "fid.h" 27 28 /** 29 * struct p9_rdir - readdir accounting 30 * @head: start offset of current dirread buffer 31 * @tail: end offset of current dirread buffer 32 * @buf: dirread buffer 33 * 34 * private structure for keeping track of readdir 35 * allocated on demand 36 */ 37 38 struct p9_rdir { 39 int head; 40 int tail; 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 = kzalloc(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 while (1) { 108 if (rdir->tail == rdir->head) { 109 struct iov_iter to; 110 int n; 111 112 iov_iter_kvec(&to, READ, &kvec, 1, buflen); 113 n = p9_client_read(file->private_data, ctx->pos, &to, 114 &err); 115 if (err) 116 return err; 117 if (n == 0) 118 return 0; 119 120 rdir->head = 0; 121 rdir->tail = n; 122 } 123 while (rdir->head < rdir->tail) { 124 err = p9stat_read(fid->clnt, rdir->buf + rdir->head, 125 rdir->tail - rdir->head, &st); 126 if (err <= 0) { 127 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 128 return -EIO; 129 } 130 131 over = !dir_emit(ctx, st.name, strlen(st.name), 132 v9fs_qid2ino(&st.qid), dt_type(&st)); 133 p9stat_free(&st); 134 if (over) 135 return 0; 136 137 rdir->head += err; 138 ctx->pos += err; 139 } 140 } 141 } 142 143 /** 144 * v9fs_dir_readdir_dotl - iterate through a directory 145 * @file: opened file structure 146 * @ctx: actor we feed the entries to 147 * 148 */ 149 static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx) 150 { 151 int err = 0; 152 struct p9_fid *fid; 153 int buflen; 154 struct p9_rdir *rdir; 155 struct p9_dirent curdirent; 156 157 p9_debug(P9_DEBUG_VFS, "name %pD\n", file); 158 fid = file->private_data; 159 160 buflen = fid->clnt->msize - P9_READDIRHDRSZ; 161 162 rdir = v9fs_alloc_rdir_buf(file, buflen); 163 if (!rdir) 164 return -ENOMEM; 165 166 while (1) { 167 if (rdir->tail == rdir->head) { 168 err = p9_client_readdir(fid, rdir->buf, buflen, 169 ctx->pos); 170 if (err <= 0) 171 return err; 172 173 rdir->head = 0; 174 rdir->tail = err; 175 } 176 177 while (rdir->head < rdir->tail) { 178 179 err = p9dirent_read(fid->clnt, rdir->buf + rdir->head, 180 rdir->tail - rdir->head, 181 &curdirent); 182 if (err < 0) { 183 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 184 return -EIO; 185 } 186 187 if (!dir_emit(ctx, curdirent.d_name, 188 strlen(curdirent.d_name), 189 v9fs_qid2ino(&curdirent.qid), 190 curdirent.d_type)) 191 return 0; 192 193 ctx->pos = curdirent.d_off; 194 rdir->head += err; 195 } 196 } 197 } 198 199 200 /** 201 * v9fs_dir_release - close a directory 202 * @inode: inode of the directory 203 * @filp: file pointer to a directory 204 * 205 */ 206 207 int v9fs_dir_release(struct inode *inode, struct file *filp) 208 { 209 struct v9fs_inode *v9inode = V9FS_I(inode); 210 struct p9_fid *fid; 211 __le32 version; 212 loff_t i_size; 213 214 fid = filp->private_data; 215 p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n", 216 inode, filp, fid ? fid->fid : -1); 217 if (fid) { 218 spin_lock(&inode->i_lock); 219 hlist_del(&fid->ilist); 220 spin_unlock(&inode->i_lock); 221 p9_fid_put(fid); 222 } 223 224 if ((filp->f_mode & FMODE_WRITE)) { 225 version = cpu_to_le32(v9inode->qid.version); 226 i_size = i_size_read(inode); 227 fscache_unuse_cookie(v9fs_inode_cookie(v9inode), 228 &version, &i_size); 229 } else { 230 fscache_unuse_cookie(v9fs_inode_cookie(v9inode), NULL, NULL); 231 } 232 return 0; 233 } 234 235 const struct file_operations v9fs_dir_operations = { 236 .read = generic_read_dir, 237 .llseek = generic_file_llseek, 238 .iterate_shared = v9fs_dir_readdir, 239 .open = v9fs_file_open, 240 .release = v9fs_dir_release, 241 }; 242 243 const struct file_operations v9fs_dir_operations_dotl = { 244 .read = generic_read_dir, 245 .llseek = generic_file_llseek, 246 .iterate_shared = v9fs_dir_readdir_dotl, 247 .open = v9fs_file_open, 248 .release = v9fs_dir_release, 249 .fsync = v9fs_file_fsync_dotl, 250 }; 251