1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/fs/9p/vfs_dir.c 4 * 5 * This file contains vfs directory ops for the 9P2000 protocol. 6 * 7 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> 8 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 9 */ 10 11 #include <linux/module.h> 12 #include <linux/errno.h> 13 #include <linux/fs.h> 14 #include <linux/file.h> 15 #include <linux/stat.h> 16 #include <linux/string.h> 17 #include <linux/sched.h> 18 #include <linux/inet.h> 19 #include <linux/idr.h> 20 #include <linux/slab.h> 21 #include <linux/uio.h> 22 #include <net/9p/9p.h> 23 #include <net/9p/client.h> 24 25 #include "v9fs.h" 26 #include "v9fs_vfs.h" 27 #include "fid.h" 28 29 /** 30 * struct p9_rdir - readdir accounting 31 * @head: start offset of current dirread buffer 32 * @tail: end offset of current dirread buffer 33 * @buf: dirread buffer 34 * 35 * private structure for keeping track of readdir 36 * allocated on demand 37 */ 38 39 struct p9_rdir { 40 int head; 41 int tail; 42 uint8_t buf[]; 43 }; 44 45 /** 46 * dt_type - return file type 47 * @mistat: mistat structure 48 * 49 */ 50 51 static inline int dt_type(struct p9_wstat *mistat) 52 { 53 unsigned long perm = mistat->mode; 54 int rettype = DT_REG; 55 56 if (perm & P9_DMDIR) 57 rettype = DT_DIR; 58 if (perm & P9_DMSYMLINK) 59 rettype = DT_LNK; 60 61 return rettype; 62 } 63 64 /** 65 * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir 66 * @filp: opened file structure 67 * @buflen: Length in bytes of buffer to allocate 68 * 69 */ 70 71 static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen) 72 { 73 struct p9_fid *fid = filp->private_data; 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 iov_iter_kvec(&to, READ, &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 - close a 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 p9_fid *fid; 209 210 fid = filp->private_data; 211 p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n", 212 inode, filp, fid ? fid->fid : -1); 213 spin_lock(&inode->i_lock); 214 hlist_del(&fid->ilist); 215 spin_unlock(&inode->i_lock); 216 if (fid) 217 p9_client_clunk(fid); 218 return 0; 219 } 220 221 const struct file_operations v9fs_dir_operations = { 222 .read = generic_read_dir, 223 .llseek = generic_file_llseek, 224 .iterate_shared = v9fs_dir_readdir, 225 .open = v9fs_file_open, 226 .release = v9fs_dir_release, 227 }; 228 229 const struct file_operations v9fs_dir_operations_dotl = { 230 .read = generic_read_dir, 231 .llseek = generic_file_llseek, 232 .iterate_shared = v9fs_dir_readdir_dotl, 233 .open = v9fs_file_open, 234 .release = v9fs_dir_release, 235 .fsync = v9fs_file_fsync_dotl, 236 }; 237