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 = VM_READAHEAD_PAGES; 85 86 sb->s_flags |= SB_ACTIVE | SB_DIRSYNC; 87 if (!v9ses->cache) 88 sb->s_flags |= SB_SYNCHRONOUS; 89 90 #ifdef CONFIG_9P_FS_POSIX_ACL 91 if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL) 92 sb->s_flags |= SB_POSIXACL; 93 #endif 94 95 return 0; 96 } 97 98 /** 99 * v9fs_mount - mount a superblock 100 * @fs_type: file system type 101 * @flags: mount flags 102 * @dev_name: device name that was mounted 103 * @data: mount options 104 * 105 */ 106 107 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags, 108 const char *dev_name, void *data) 109 { 110 struct super_block *sb = NULL; 111 struct inode *inode = NULL; 112 struct dentry *root = NULL; 113 struct v9fs_session_info *v9ses = NULL; 114 umode_t mode = S_IRWXUGO | S_ISVTX; 115 struct p9_fid *fid; 116 int retval = 0; 117 118 p9_debug(P9_DEBUG_VFS, "\n"); 119 120 v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL); 121 if (!v9ses) 122 return ERR_PTR(-ENOMEM); 123 124 fid = v9fs_session_init(v9ses, dev_name, data); 125 if (IS_ERR(fid)) { 126 retval = PTR_ERR(fid); 127 goto free_session; 128 } 129 130 sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses); 131 if (IS_ERR(sb)) { 132 retval = PTR_ERR(sb); 133 goto clunk_fid; 134 } 135 retval = v9fs_fill_super(sb, v9ses, flags); 136 if (retval) 137 goto release_sb; 138 139 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) 140 sb->s_d_op = &v9fs_cached_dentry_operations; 141 else 142 sb->s_d_op = &v9fs_dentry_operations; 143 144 inode = v9fs_get_inode(sb, S_IFDIR | mode, 0); 145 if (IS_ERR(inode)) { 146 retval = PTR_ERR(inode); 147 goto release_sb; 148 } 149 150 root = d_make_root(inode); 151 if (!root) { 152 retval = -ENOMEM; 153 goto release_sb; 154 } 155 sb->s_root = root; 156 if (v9fs_proto_dotl(v9ses)) { 157 struct p9_stat_dotl *st = NULL; 158 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC); 159 if (IS_ERR(st)) { 160 retval = PTR_ERR(st); 161 goto release_sb; 162 } 163 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid); 164 v9fs_stat2inode_dotl(st, d_inode(root), 0); 165 kfree(st); 166 } else { 167 struct p9_wstat *st = NULL; 168 st = p9_client_stat(fid); 169 if (IS_ERR(st)) { 170 retval = PTR_ERR(st); 171 goto release_sb; 172 } 173 174 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid); 175 v9fs_stat2inode(st, d_inode(root), sb, 0); 176 177 p9stat_free(st); 178 kfree(st); 179 } 180 retval = v9fs_get_acl(inode, fid); 181 if (retval) 182 goto release_sb; 183 v9fs_fid_add(root, fid); 184 185 p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n"); 186 return dget(sb->s_root); 187 188 clunk_fid: 189 p9_client_clunk(fid); 190 v9fs_session_close(v9ses); 191 free_session: 192 kfree(v9ses); 193 return ERR_PTR(retval); 194 195 release_sb: 196 /* 197 * we will do the session_close and root dentry release 198 * in the below call. But we need to clunk fid, because we haven't 199 * attached the fid to dentry so it won't get clunked 200 * automatically. 201 */ 202 p9_client_clunk(fid); 203 deactivate_locked_super(sb); 204 return ERR_PTR(retval); 205 } 206 207 /** 208 * v9fs_kill_super - Kill Superblock 209 * @s: superblock 210 * 211 */ 212 213 static void v9fs_kill_super(struct super_block *s) 214 { 215 struct v9fs_session_info *v9ses = s->s_fs_info; 216 217 p9_debug(P9_DEBUG_VFS, " %p\n", s); 218 219 kill_anon_super(s); 220 221 v9fs_session_cancel(v9ses); 222 v9fs_session_close(v9ses); 223 kfree(v9ses); 224 s->s_fs_info = NULL; 225 p9_debug(P9_DEBUG_VFS, "exiting kill_super\n"); 226 } 227 228 static void 229 v9fs_umount_begin(struct super_block *sb) 230 { 231 struct v9fs_session_info *v9ses; 232 233 v9ses = sb->s_fs_info; 234 v9fs_session_begin_cancel(v9ses); 235 } 236 237 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf) 238 { 239 struct v9fs_session_info *v9ses; 240 struct p9_fid *fid; 241 struct p9_rstatfs rs; 242 int res; 243 244 fid = v9fs_fid_lookup(dentry); 245 if (IS_ERR(fid)) { 246 res = PTR_ERR(fid); 247 goto done; 248 } 249 250 v9ses = v9fs_dentry2v9ses(dentry); 251 if (v9fs_proto_dotl(v9ses)) { 252 res = p9_client_statfs(fid, &rs); 253 if (res == 0) { 254 buf->f_type = rs.type; 255 buf->f_bsize = rs.bsize; 256 buf->f_blocks = rs.blocks; 257 buf->f_bfree = rs.bfree; 258 buf->f_bavail = rs.bavail; 259 buf->f_files = rs.files; 260 buf->f_ffree = rs.ffree; 261 buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL; 262 buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL; 263 buf->f_namelen = rs.namelen; 264 } 265 if (res != -ENOSYS) 266 goto done; 267 } 268 res = simple_statfs(dentry, buf); 269 done: 270 return res; 271 } 272 273 static int v9fs_drop_inode(struct inode *inode) 274 { 275 struct v9fs_session_info *v9ses; 276 v9ses = v9fs_inode2v9ses(inode); 277 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) 278 return generic_drop_inode(inode); 279 /* 280 * in case of non cached mode always drop the 281 * the inode because we want the inode attribute 282 * to always match that on the server. 283 */ 284 return 1; 285 } 286 287 static int v9fs_write_inode(struct inode *inode, 288 struct writeback_control *wbc) 289 { 290 int ret; 291 struct p9_wstat wstat; 292 struct v9fs_inode *v9inode; 293 /* 294 * send an fsync request to server irrespective of 295 * wbc->sync_mode. 296 */ 297 p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode); 298 v9inode = V9FS_I(inode); 299 if (!v9inode->writeback_fid) 300 return 0; 301 v9fs_blank_wstat(&wstat); 302 303 ret = p9_client_wstat(v9inode->writeback_fid, &wstat); 304 if (ret < 0) { 305 __mark_inode_dirty(inode, I_DIRTY_DATASYNC); 306 return ret; 307 } 308 return 0; 309 } 310 311 static int v9fs_write_inode_dotl(struct inode *inode, 312 struct writeback_control *wbc) 313 { 314 int ret; 315 struct v9fs_inode *v9inode; 316 /* 317 * send an fsync request to server irrespective of 318 * wbc->sync_mode. 319 */ 320 v9inode = V9FS_I(inode); 321 p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n", 322 __func__, inode, v9inode->writeback_fid); 323 if (!v9inode->writeback_fid) 324 return 0; 325 326 ret = p9_client_fsync(v9inode->writeback_fid, 0); 327 if (ret < 0) { 328 __mark_inode_dirty(inode, I_DIRTY_DATASYNC); 329 return ret; 330 } 331 return 0; 332 } 333 334 static const struct super_operations v9fs_super_ops = { 335 .alloc_inode = v9fs_alloc_inode, 336 .free_inode = v9fs_free_inode, 337 .statfs = simple_statfs, 338 .evict_inode = v9fs_evict_inode, 339 .show_options = v9fs_show_options, 340 .umount_begin = v9fs_umount_begin, 341 .write_inode = v9fs_write_inode, 342 }; 343 344 static const struct super_operations v9fs_super_ops_dotl = { 345 .alloc_inode = v9fs_alloc_inode, 346 .free_inode = v9fs_free_inode, 347 .statfs = v9fs_statfs, 348 .drop_inode = v9fs_drop_inode, 349 .evict_inode = v9fs_evict_inode, 350 .show_options = v9fs_show_options, 351 .umount_begin = v9fs_umount_begin, 352 .write_inode = v9fs_write_inode_dotl, 353 }; 354 355 struct file_system_type v9fs_fs_type = { 356 .name = "9p", 357 .mount = v9fs_mount, 358 .kill_sb = v9fs_kill_super, 359 .owner = THIS_MODULE, 360 .fs_flags = FS_RENAME_DOES_D_MOVE, 361 }; 362 MODULE_ALIAS_FS("9p"); 363