fs/9p/vfs_super.c

   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");