1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/fs/9p/vfs_super.c 4 * 5 * This file contians superblock ops for 9P2000. It is intended that 6 * you mount this file system on directories. 7 * 8 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> 9 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/errno.h> 15 #include <linux/fs.h> 16 #include <linux/file.h> 17 #include <linux/stat.h> 18 #include <linux/string.h> 19 #include <linux/inet.h> 20 #include <linux/pagemap.h> 21 #include <linux/mount.h> 22 #include <linux/idr.h> 23 #include <linux/sched.h> 24 #include <linux/slab.h> 25 #include <linux/statfs.h> 26 #include <linux/magic.h> 27 #include <net/9p/9p.h> 28 #include <net/9p/client.h> 29 30 #include "v9fs.h" 31 #include "v9fs_vfs.h" 32 #include "fid.h" 33 #include "xattr.h" 34 #include "acl.h" 35 36 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl; 37 38 /** 39 * v9fs_set_super - set the superblock 40 * @s: super block 41 * @data: file system specific data 42 * 43 */ 44 45 static int v9fs_set_super(struct super_block *s, void *data) 46 { 47 s->s_fs_info = data; 48 return set_anon_super(s, data); 49 } 50 51 /** 52 * v9fs_fill_super - populate superblock with info 53 * @sb: superblock 54 * @v9ses: session information 55 * @flags: flags propagated from v9fs_mount() 56 * 57 */ 58 59 static int 60 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses, 61 int flags) 62 { 63 int ret; 64 65 sb->s_maxbytes = MAX_LFS_FILESIZE; 66 sb->s_blocksize_bits = fls(v9ses->maxdata - 1); 67 sb->s_blocksize = 1 << sb->s_blocksize_bits; 68 sb->s_magic = V9FS_MAGIC; 69 if (v9fs_proto_dotl(v9ses)) { 70 sb->s_op = &v9fs_super_ops_dotl; 71 sb->s_xattr = v9fs_xattr_handlers; 72 } else { 73 sb->s_op = &v9fs_super_ops; 74 sb->s_time_max = U32_MAX; 75 } 76 77 sb->s_time_min = 0; 78 79 ret = super_setup_bdi(sb); 80 if (ret) 81 return ret; 82 83 if (!v9ses->cache) { 84 sb->s_bdi->ra_pages = 0; 85 sb->s_bdi->io_pages = 0; 86 } 87 88 sb->s_flags |= SB_ACTIVE | SB_DIRSYNC; 89 if (!v9ses->cache) 90 sb->s_flags |= SB_SYNCHRONOUS; 91 92 #ifdef CONFIG_9P_FS_POSIX_ACL 93 if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL) 94 sb->s_flags |= SB_POSIXACL; 95 #endif 96 97 return 0; 98 } 99 100 /** 101 * v9fs_mount - mount a superblock 102 * @fs_type: file system type 103 * @flags: mount flags 104 * @dev_name: device name that was mounted 105 * @data: mount options 106 * 107 */ 108 109 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags, 110 const char *dev_name, void *data) 111 { 112 struct super_block *sb = NULL; 113 struct inode *inode = NULL; 114 struct dentry *root = NULL; 115 struct v9fs_session_info *v9ses = NULL; 116 umode_t mode = S_IRWXUGO | S_ISVTX; 117 struct p9_fid *fid; 118 int retval = 0; 119 120 p9_debug(P9_DEBUG_VFS, "\n"); 121 122 v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL); 123 if (!v9ses) 124 return ERR_PTR(-ENOMEM); 125 126 fid = v9fs_session_init(v9ses, dev_name, data); 127 if (IS_ERR(fid)) { 128 retval = PTR_ERR(fid); 129 goto free_session; 130 } 131 132 sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses); 133 if (IS_ERR(sb)) { 134 retval = PTR_ERR(sb); 135 goto clunk_fid; 136 } 137 retval = v9fs_fill_super(sb, v9ses, flags); 138 if (retval) 139 goto release_sb; 140 141 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) 142 sb->s_d_op = &v9fs_cached_dentry_operations; 143 else 144 sb->s_d_op = &v9fs_dentry_operations; 145 146 inode = v9fs_get_inode(sb, S_IFDIR | mode, 0); 147 if (IS_ERR(inode)) { 148 retval = PTR_ERR(inode); 149 goto release_sb; 150 } 151 152 root = d_make_root(inode); 153 if (!root) { 154 retval = -ENOMEM; 155 goto release_sb; 156 } 157 sb->s_root = root; 158 if (v9fs_proto_dotl(v9ses)) { 159 struct p9_stat_dotl *st = NULL; 160 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC); 161 if (IS_ERR(st)) { 162 retval = PTR_ERR(st); 163 goto release_sb; 164 } 165 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid); 166 v9fs_stat2inode_dotl(st, d_inode(root), 0); 167 kfree(st); 168 } else { 169 struct p9_wstat *st = NULL; 170 st = p9_client_stat(fid); 171 if (IS_ERR(st)) { 172 retval = PTR_ERR(st); 173 goto release_sb; 174 } 175 176 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid); 177 v9fs_stat2inode(st, d_inode(root), sb, 0); 178 179 p9stat_free(st); 180 kfree(st); 181 } 182 retval = v9fs_get_acl(inode, fid); 183 if (retval) 184 goto release_sb; 185 v9fs_fid_add(root, fid); 186 187 p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n"); 188 return dget(sb->s_root); 189 190 clunk_fid: 191 p9_client_clunk(fid); 192 v9fs_session_close(v9ses); 193 free_session: 194 kfree(v9ses); 195 return ERR_PTR(retval); 196 197 release_sb: 198 /* 199 * we will do the session_close and root dentry release 200 * in the below call. But we need to clunk fid, because we haven't 201 * attached the fid to dentry so it won't get clunked 202 * automatically. 203 */ 204 p9_client_clunk(fid); 205 deactivate_locked_super(sb); 206 return ERR_PTR(retval); 207 } 208 209 /** 210 * v9fs_kill_super - Kill Superblock 211 * @s: superblock 212 * 213 */ 214 215 static void v9fs_kill_super(struct super_block *s) 216 { 217 struct v9fs_session_info *v9ses = s->s_fs_info; 218 219 p9_debug(P9_DEBUG_VFS, " %p\n", s); 220 221 kill_anon_super(s); 222 223 v9fs_session_cancel(v9ses); 224 v9fs_session_close(v9ses); 225 kfree(v9ses); 226 s->s_fs_info = NULL; 227 p9_debug(P9_DEBUG_VFS, "exiting kill_super\n"); 228 } 229 230 static void 231 v9fs_umount_begin(struct super_block *sb) 232 { 233 struct v9fs_session_info *v9ses; 234 235 v9ses = sb->s_fs_info; 236 v9fs_session_begin_cancel(v9ses); 237 } 238 239 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf) 240 { 241 struct v9fs_session_info *v9ses; 242 struct p9_fid *fid; 243 struct p9_rstatfs rs; 244 int res; 245 246 fid = v9fs_fid_lookup(dentry); 247 if (IS_ERR(fid)) { 248 res = PTR_ERR(fid); 249 goto done; 250 } 251 252 v9ses = v9fs_dentry2v9ses(dentry); 253 if (v9fs_proto_dotl(v9ses)) { 254 res = p9_client_statfs(fid, &rs); 255 if (res == 0) { 256 buf->f_type = rs.type; 257 buf->f_bsize = rs.bsize; 258 buf->f_blocks = rs.blocks; 259 buf->f_bfree = rs.bfree; 260 buf->f_bavail = rs.bavail; 261 buf->f_files = rs.files; 262 buf->f_ffree = rs.ffree; 263 buf->f_fsid = u64_to_fsid(rs.fsid); 264 buf->f_namelen = rs.namelen; 265 } 266 if (res != -ENOSYS) 267 goto done; 268 } 269 res = simple_statfs(dentry, buf); 270 done: 271 return res; 272 } 273 274 static int v9fs_drop_inode(struct inode *inode) 275 { 276 struct v9fs_session_info *v9ses; 277 v9ses = v9fs_inode2v9ses(inode); 278 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) 279 return generic_drop_inode(inode); 280 /* 281 * in case of non cached mode always drop the 282 * the inode because we want the inode attribute 283 * to always match that on the server. 284 */ 285 return 1; 286 } 287 288 static int v9fs_write_inode(struct inode *inode, 289 struct writeback_control *wbc) 290 { 291 int ret; 292 struct p9_wstat wstat; 293 struct v9fs_inode *v9inode; 294 /* 295 * send an fsync request to server irrespective of 296 * wbc->sync_mode. 297 */ 298 p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode); 299 v9inode = V9FS_I(inode); 300 if (!v9inode->writeback_fid) 301 return 0; 302 v9fs_blank_wstat(&wstat); 303 304 ret = p9_client_wstat(v9inode->writeback_fid, &wstat); 305 if (ret < 0) { 306 __mark_inode_dirty(inode, I_DIRTY_DATASYNC); 307 return ret; 308 } 309 return 0; 310 } 311 312 static int v9fs_write_inode_dotl(struct inode *inode, 313 struct writeback_control *wbc) 314 { 315 int ret; 316 struct v9fs_inode *v9inode; 317 /* 318 * send an fsync request to server irrespective of 319 * wbc->sync_mode. 320 */ 321 v9inode = V9FS_I(inode); 322 p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n", 323 __func__, inode, v9inode->writeback_fid); 324 if (!v9inode->writeback_fid) 325 return 0; 326 327 ret = p9_client_fsync(v9inode->writeback_fid, 0); 328 if (ret < 0) { 329 __mark_inode_dirty(inode, I_DIRTY_DATASYNC); 330 return ret; 331 } 332 return 0; 333 } 334 335 static const struct super_operations v9fs_super_ops = { 336 .alloc_inode = v9fs_alloc_inode, 337 .free_inode = v9fs_free_inode, 338 .statfs = simple_statfs, 339 .evict_inode = v9fs_evict_inode, 340 .show_options = v9fs_show_options, 341 .umount_begin = v9fs_umount_begin, 342 .write_inode = v9fs_write_inode, 343 }; 344 345 static const struct super_operations v9fs_super_ops_dotl = { 346 .alloc_inode = v9fs_alloc_inode, 347 .free_inode = v9fs_free_inode, 348 .statfs = v9fs_statfs, 349 .drop_inode = v9fs_drop_inode, 350 .evict_inode = v9fs_evict_inode, 351 .show_options = v9fs_show_options, 352 .umount_begin = v9fs_umount_begin, 353 .write_inode = v9fs_write_inode_dotl, 354 }; 355 356 struct file_system_type v9fs_fs_type = { 357 .name = "9p", 358 .mount = v9fs_mount, 359 .kill_sb = v9fs_kill_super, 360 .owner = THIS_MODULE, 361 .fs_flags = FS_RENAME_DOES_D_MOVE, 362 }; 363 MODULE_ALIAS_FS("9p"); 364