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/slab.h> 18 #include <linux/uio.h> 19 #include <linux/fscache.h> 20 #include <net/9p/9p.h> 21 #include <net/9p/client.h> 22 23 #include "v9fs.h" 24 #include "v9fs_vfs.h" 25 #include "fid.h" 26 27 /** 28 * struct p9_rdir - readdir accounting 29 * @head: start offset of current dirread buffer 30 * @tail: end offset of current dirread buffer 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 uint8_t buf[]; 41 }; 42 43 /** 44 * dt_type - return file type 45 * @mistat: mistat structure 46 * 47 */ 48 49 static inline int dt_type(struct p9_wstat *mistat) 50 { 51 unsigned long perm = mistat->mode; 52 int rettype = DT_REG; 53 54 if (perm & P9_DMDIR) 55 rettype = DT_DIR; 56 if (perm & P9_DMSYMLINK) 57 rettype = DT_LNK; 58 59 return rettype; 60 } 61 62 /** 63 * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir 64 * @filp: opened file structure 65 * @buflen: Length in bytes of buffer to allocate 66 * 67 */ 68 69 static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen) 70 { 71 struct p9_fid *fid = filp->private_data; 72 73 if (!fid->rdir) 74 fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL); 75 return fid->rdir; 76 } 77 78 /** 79 * v9fs_dir_readdir - iterate through a directory 80 * @file: opened file structure 81 * @ctx: actor we feed the entries to 82 * 83 */ 84 85 static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx) 86 { 87 bool over; 88 struct p9_wstat st; 89 int err = 0; 90 struct p9_fid *fid; 91 int buflen; 92 struct p9_rdir *rdir; 93 struct kvec kvec; 94 95 p9_debug(P9_DEBUG_VFS, "name %pD\n", file); 96 fid = file->private_data; 97 98 buflen = fid->clnt->msize - P9_IOHDRSZ; 99 100 rdir = v9fs_alloc_rdir_buf(file, buflen); 101 if (!rdir) 102 return -ENOMEM; 103 kvec.iov_base = rdir->buf; 104 kvec.iov_len = buflen; 105 106 while (1) { 107 if (rdir->tail == rdir->head) { 108 struct iov_iter to; 109 int n; 110 111 iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buflen); 112 n = p9_client_read(file->private_data, ctx->pos, &to, 113 &err); 114 if (err) 115 return err; 116 if (n == 0) 117 return 0; 118 119 rdir->head = 0; 120 rdir->tail = n; 121 } 122 while (rdir->head < rdir->tail) { 123 err = p9stat_read(fid->clnt, rdir->buf + rdir->head, 124 rdir->tail - rdir->head, &st); 125 if (err <= 0) { 126 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 127 return -EIO; 128 } 129 130 over = !dir_emit(ctx, st.name, strlen(st.name), 131 v9fs_qid2ino(&st.qid), dt_type(&st)); 132 p9stat_free(&st); 133 if (over) 134 return 0; 135 136 rdir->head += err; 137 ctx->pos += err; 138 } 139 } 140 } 141 142 /** 143 * v9fs_dir_readdir_dotl - iterate through a directory 144 * @file: opened file structure 145 * @ctx: actor we feed the entries to 146 * 147 */ 148 static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx) 149 { 150 int err = 0; 151 struct p9_fid *fid; 152 int buflen; 153 struct p9_rdir *rdir; 154 struct p9_dirent curdirent; 155 156 p9_debug(P9_DEBUG_VFS, "name %pD\n", file); 157 fid = file->private_data; 158 159 buflen = fid->clnt->msize - P9_READDIRHDRSZ; 160 161 rdir = v9fs_alloc_rdir_buf(file, buflen); 162 if (!rdir) 163 return -ENOMEM; 164 165 while (1) { 166 if (rdir->tail == rdir->head) { 167 err = p9_client_readdir(fid, rdir->buf, buflen, 168 ctx->pos); 169 if (err <= 0) 170 return err; 171 172 rdir->head = 0; 173 rdir->tail = err; 174 } 175 176 while (rdir->head < rdir->tail) { 177 178 err = p9dirent_read(fid->clnt, rdir->buf + rdir->head, 179 rdir->tail - rdir->head, 180 &curdirent); 181 if (err < 0) { 182 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 183 return -EIO; 184 } 185 186 if (!dir_emit(ctx, curdirent.d_name, 187 strlen(curdirent.d_name), 188 v9fs_qid2ino(&curdirent.qid), 189 curdirent.d_type)) 190 return 0; 191 192 ctx->pos = curdirent.d_off; 193 rdir->head += err; 194 } 195 } 196 } 197 198 199 /** 200 * v9fs_dir_release - called on a close of a file or directory 201 * @inode: inode of the directory 202 * @filp: file pointer to a directory 203 * 204 */ 205 206 int v9fs_dir_release(struct inode *inode, struct file *filp) 207 { 208 struct v9fs_inode *v9inode = V9FS_I(inode); 209 struct p9_fid *fid; 210 __le32 version; 211 loff_t i_size; 212 int retval = 0; 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 retval = 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 retval; 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