fs/9p/vfs_super.c

   1 /*
   2  *  linux/fs/9p/vfs_super.c
   3  *
   4  * This file contians superblock ops for 9P2000. It is intended that
   5  * you mount this file system on directories.
   6  *
   7  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2
  12  *  as published by the Free Software Foundation.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to:
  21  *  Free Software Foundation
  22  *  51 Franklin Street, Fifth Floor
  23  *  Boston, MA  02111-1301  USA
  24  *
  25  */
  26
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/fs.h>
  31 #include <linux/file.h>
  32 #include <linux/stat.h>
  33 #include <linux/string.h>
  34 #include <linux/inet.h>
  35 #include <linux/pagemap.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/mount.h>
  38 #include <linux/idr.h>
  39 #include <linux/sched.h>
  40 #include <linux/slab.h>
  41 #include <linux/statfs.h>
  42 #include <linux/magic.h>
  43 #include <net/9p/9p.h>
  44 #include <net/9p/client.h>
  45
  46 #include "v9fs.h"
  47 #include "v9fs_vfs.h"
  48 #include "fid.h"
  49 #include "xattr.h"
  50 #include "acl.h"
  51
  52 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
  53
  54 /**
  55  * v9fs_set_super - set the superblock
  56  * @s: super block
  57  * @data: file system specific data
  58  *
  59  */
  60
  61 static int v9fs_set_super(struct super_block *s, void *data)
  62 {
  63         s->s_fs_info = data;
  64         return set_anon_super(s, data);
  65 }
  66
  67 /**
  68  * v9fs_fill_super - populate superblock with info
  69  * @sb: superblock
  70  * @v9ses: session information
  71  * @flags: flags propagated from v9fs_mount()
  72  *
  73  */
  74
  75 static int
  76 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  77                 int flags, void *data)
  78 {
  79         int ret;
  80
  81         sb->s_maxbytes = MAX_LFS_FILESIZE;
  82         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  83         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  84         sb->s_magic = V9FS_MAGIC;
  85         if (v9fs_proto_dotl(v9ses)) {
  86                 sb->s_op = &v9fs_super_ops_dotl;
  87                 sb->s_xattr = v9fs_xattr_handlers;
  88         } else
  89                 sb->s_op = &v9fs_super_ops;
  90
  91         ret = super_setup_bdi(sb);
  92         if (ret)
  93                 return ret;
  94
  95         if (v9ses->cache)
  96                 sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_SIZE;
  97
  98         sb->s_flags |= MS_ACTIVE | MS_DIRSYNC | MS_NOATIME;
  99         if (!v9ses->cache)
 100                 sb->s_flags |= MS_SYNCHRONOUS;
 101
 102 #ifdef CONFIG_9P_FS_POSIX_ACL
 103         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
 104                 sb->s_flags |= MS_POSIXACL;
 105 #endif
 106
 107         save_mount_options(sb, data);
 108         return 0;
 109 }
 110
 111 /**
 112  * v9fs_mount - mount a superblock
 113  * @fs_type: file system type
 114  * @flags: mount flags
 115  * @dev_name: device name that was mounted
 116  * @data: mount options
 117  *
 118  */
 119
 120 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 121                        const char *dev_name, void *data)
 122 {
 123         struct super_block *sb = NULL;
 124         struct inode *inode = NULL;
 125         struct dentry *root = NULL;
 126         struct v9fs_session_info *v9ses = NULL;
 127         umode_t mode = S_IRWXUGO | S_ISVTX;
 128         struct p9_fid *fid;
 129         int retval = 0;
 130
 131         p9_debug(P9_DEBUG_VFS, "\n");
 132
 133         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 134         if (!v9ses)
 135                 return ERR_PTR(-ENOMEM);
 136
 137         fid = v9fs_session_init(v9ses, dev_name, data);
 138         if (IS_ERR(fid)) {
 139                 retval = PTR_ERR(fid);
 140                 goto free_session;
 141         }
 142
 143         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 144         if (IS_ERR(sb)) {
 145                 retval = PTR_ERR(sb);
 146                 goto clunk_fid;
 147         }
 148         retval = v9fs_fill_super(sb, v9ses, flags, data);
 149         if (retval)
 150                 goto release_sb;
 151
 152         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 153                 sb->s_d_op = &v9fs_cached_dentry_operations;
 154         else
 155                 sb->s_d_op = &v9fs_dentry_operations;
 156
 157         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 158         if (IS_ERR(inode)) {
 159                 retval = PTR_ERR(inode);
 160                 goto release_sb;
 161         }
 162
 163         root = d_make_root(inode);
 164         if (!root) {
 165                 retval = -ENOMEM;
 166                 goto release_sb;
 167         }
 168         sb->s_root = root;
 169         if (v9fs_proto_dotl(v9ses)) {
 170                 struct p9_stat_dotl *st = NULL;
 171                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 172                 if (IS_ERR(st)) {
 173                         retval = PTR_ERR(st);
 174                         goto release_sb;
 175                 }
 176                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 177                 v9fs_stat2inode_dotl(st, d_inode(root));
 178                 kfree(st);
 179         } else {
 180                 struct p9_wstat *st = NULL;
 181                 st = p9_client_stat(fid);
 182                 if (IS_ERR(st)) {
 183                         retval = PTR_ERR(st);
 184                         goto release_sb;
 185                 }
 186
 187                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 188                 v9fs_stat2inode(st, d_inode(root), sb);
 189
 190                 p9stat_free(st);
 191                 kfree(st);
 192         }
 193         retval = v9fs_get_acl(inode, fid);
 194         if (retval)
 195                 goto release_sb;
 196         v9fs_fid_add(root, fid);
 197
 198         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 199         return dget(sb->s_root);
 200
 201 clunk_fid:
 202         p9_client_clunk(fid);
 203         v9fs_session_close(v9ses);
 204 free_session:
 205         kfree(v9ses);
 206         return ERR_PTR(retval);
 207
 208 release_sb:
 209         /*
 210          * we will do the session_close and root dentry release
 211          * in the below call. But we need to clunk fid, because we haven't
 212          * attached the fid to dentry so it won't get clunked
 213          * automatically.
 214          */
 215         p9_client_clunk(fid);
 216         deactivate_locked_super(sb);
 217         return ERR_PTR(retval);
 218 }
 219
 220 /**
 221  * v9fs_kill_super - Kill Superblock
 222  * @s: superblock
 223  *
 224  */
 225
 226 static void v9fs_kill_super(struct super_block *s)
 227 {
 228         struct v9fs_session_info *v9ses = s->s_fs_info;
 229
 230         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 231
 232         kill_anon_super(s);
 233
 234         v9fs_session_cancel(v9ses);
 235         v9fs_session_close(v9ses);
 236         kfree(v9ses);
 237         s->s_fs_info = NULL;
 238         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 239 }
 240
 241 static void
 242 v9fs_umount_begin(struct super_block *sb)
 243 {
 244         struct v9fs_session_info *v9ses;
 245
 246         v9ses = sb->s_fs_info;
 247         v9fs_session_begin_cancel(v9ses);
 248 }
 249
 250 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 251 {
 252         struct v9fs_session_info *v9ses;
 253         struct p9_fid *fid;
 254         struct p9_rstatfs rs;
 255         int res;
 256
 257         fid = v9fs_fid_lookup(dentry);
 258         if (IS_ERR(fid)) {
 259                 res = PTR_ERR(fid);
 260                 goto done;
 261         }
 262
 263         v9ses = v9fs_dentry2v9ses(dentry);
 264         if (v9fs_proto_dotl(v9ses)) {
 265                 res = p9_client_statfs(fid, &rs);
 266                 if (res == 0) {
 267                         buf->f_type = rs.type;
 268                         buf->f_bsize = rs.bsize;
 269                         buf->f_blocks = rs.blocks;
 270                         buf->f_bfree = rs.bfree;
 271                         buf->f_bavail = rs.bavail;
 272                         buf->f_files = rs.files;
 273                         buf->f_ffree = rs.ffree;
 274                         buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
 275                         buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
 276                         buf->f_namelen = rs.namelen;
 277                 }
 278                 if (res != -ENOSYS)
 279                         goto done;
 280         }
 281         res = simple_statfs(dentry, buf);
 282 done:
 283         return res;
 284 }
 285
 286 static int v9fs_drop_inode(struct inode *inode)
 287 {
 288         struct v9fs_session_info *v9ses;
 289         v9ses = v9fs_inode2v9ses(inode);
 290         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 291                 return generic_drop_inode(inode);
 292         /*
 293          * in case of non cached mode always drop the
 294          * the inode because we want the inode attribute
 295          * to always match that on the server.
 296          */
 297         return 1;
 298 }
 299
 300 static int v9fs_write_inode(struct inode *inode,
 301                             struct writeback_control *wbc)
 302 {
 303         int ret;
 304         struct p9_wstat wstat;
 305         struct v9fs_inode *v9inode;
 306         /*
 307          * send an fsync request to server irrespective of
 308          * wbc->sync_mode.
 309          */
 310         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 311         v9inode = V9FS_I(inode);
 312         if (!v9inode->writeback_fid)
 313                 return 0;
 314         v9fs_blank_wstat(&wstat);
 315
 316         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 317         if (ret < 0) {
 318                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 319                 return ret;
 320         }
 321         return 0;
 322 }
 323
 324 static int v9fs_write_inode_dotl(struct inode *inode,
 325                                  struct writeback_control *wbc)
 326 {
 327         int ret;
 328         struct v9fs_inode *v9inode;
 329         /*
 330          * send an fsync request to server irrespective of
 331          * wbc->sync_mode.
 332          */
 333         v9inode = V9FS_I(inode);
 334         p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
 335                  __func__, inode, v9inode->writeback_fid);
 336         if (!v9inode->writeback_fid)
 337                 return 0;
 338
 339         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 340         if (ret < 0) {
 341                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 342                 return ret;
 343         }
 344         return 0;
 345 }
 346
 347 static const struct super_operations v9fs_super_ops = {
 348         .alloc_inode = v9fs_alloc_inode,
 349         .destroy_inode = v9fs_destroy_inode,
 350         .statfs = simple_statfs,
 351         .evict_inode = v9fs_evict_inode,
 352         .show_options = generic_show_options,
 353         .umount_begin = v9fs_umount_begin,
 354         .write_inode = v9fs_write_inode,
 355 };
 356
 357 static const struct super_operations v9fs_super_ops_dotl = {
 358         .alloc_inode = v9fs_alloc_inode,
 359         .destroy_inode = v9fs_destroy_inode,
 360         .statfs = v9fs_statfs,
 361         .drop_inode = v9fs_drop_inode,
 362         .evict_inode = v9fs_evict_inode,
 363         .show_options = generic_show_options,
 364         .umount_begin = v9fs_umount_begin,
 365         .write_inode = v9fs_write_inode_dotl,
 366 };
 367
 368 struct file_system_type v9fs_fs_type = {
 369         .name = "9p",
 370         .mount = v9fs_mount,
 371         .kill_sb = v9fs_kill_super,
 372         .owner = THIS_MODULE,
 373         .fs_flags = FS_RENAME_DOES_D_MOVE,
 374 };
 375 MODULE_ALIAS_FS("9p");