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 void
  76 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  77                 int flags, void *data)
  78 {
  79         sb->s_maxbytes = MAX_LFS_FILESIZE;
  80         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  81         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  82         sb->s_magic = V9FS_MAGIC;
  83         if (v9fs_proto_dotl(v9ses)) {
  84                 sb->s_op = &v9fs_super_ops_dotl;
  85                 sb->s_xattr = v9fs_xattr_handlers;
  86         } else
  87                 sb->s_op = &v9fs_super_ops;
  88         sb->s_bdi = &v9ses->bdi;
  89         if (v9ses->cache)
  90                 sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_CACHE_SIZE;
  91
  92         sb->s_flags = flags | MS_ACTIVE | MS_DIRSYNC | MS_NOATIME;
  93         if (!v9ses->cache)
  94                 sb->s_flags |= MS_SYNCHRONOUS;
  95
  96 #ifdef CONFIG_9P_FS_POSIX_ACL
  97         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
  98                 sb->s_flags |= MS_POSIXACL;
  99 #endif
 100
 101         save_mount_options(sb, data);
 102 }
 103
 104 /**
 105  * v9fs_mount - mount a superblock
 106  * @fs_type: file system type
 107  * @flags: mount flags
 108  * @dev_name: device name that was mounted
 109  * @data: mount options
 110  *
 111  */
 112
 113 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 114                        const char *dev_name, void *data)
 115 {
 116         struct super_block *sb = NULL;
 117         struct inode *inode = NULL;
 118         struct dentry *root = NULL;
 119         struct v9fs_session_info *v9ses = NULL;
 120         umode_t mode = S_IRWXUGO | S_ISVTX;
 121         struct p9_fid *fid;
 122         int retval = 0;
 123
 124         p9_debug(P9_DEBUG_VFS, "\n");
 125
 126         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 127         if (!v9ses)
 128                 return ERR_PTR(-ENOMEM);
 129
 130         fid = v9fs_session_init(v9ses, dev_name, data);
 131         if (IS_ERR(fid)) {
 132                 retval = PTR_ERR(fid);
 133                 /*
 134                  * we need to call session_close to tear down some
 135                  * of the data structure setup by session_init
 136                  */
 137                 goto close_session;
 138         }
 139
 140         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 141         if (IS_ERR(sb)) {
 142                 retval = PTR_ERR(sb);
 143                 goto clunk_fid;
 144         }
 145         v9fs_fill_super(sb, v9ses, flags, data);
 146
 147         if (v9ses->cache)
 148                 sb->s_d_op = &v9fs_cached_dentry_operations;
 149         else
 150                 sb->s_d_op = &v9fs_dentry_operations;
 151
 152         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 153         if (IS_ERR(inode)) {
 154                 retval = PTR_ERR(inode);
 155                 goto release_sb;
 156         }
 157
 158         root = d_alloc_root(inode);
 159         if (!root) {
 160                 iput(inode);
 161                 retval = -ENOMEM;
 162                 goto release_sb;
 163         }
 164         sb->s_root = root;
 165         if (v9fs_proto_dotl(v9ses)) {
 166                 struct p9_stat_dotl *st = NULL;
 167                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 168                 if (IS_ERR(st)) {
 169                         retval = PTR_ERR(st);
 170                         goto release_sb;
 171                 }
 172                 root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 173                 v9fs_stat2inode_dotl(st, root->d_inode);
 174                 kfree(st);
 175         } else {
 176                 struct p9_wstat *st = NULL;
 177                 st = p9_client_stat(fid);
 178                 if (IS_ERR(st)) {
 179                         retval = PTR_ERR(st);
 180                         goto release_sb;
 181                 }
 182
 183                 root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 184                 v9fs_stat2inode(st, root->d_inode, sb);
 185
 186                 p9stat_free(st);
 187                 kfree(st);
 188         }
 189         retval = v9fs_get_acl(inode, fid);
 190         if (retval)
 191                 goto release_sb;
 192         v9fs_fid_add(root, fid);
 193
 194         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 195         return dget(sb->s_root);
 196
 197 clunk_fid:
 198         p9_client_clunk(fid);
 199 close_session:
 200         v9fs_session_close(v9ses);
 201         kfree(v9ses);
 202         return ERR_PTR(retval);
 203
 204 release_sb:
 205         /*
 206          * we will do the session_close and root dentry release
 207          * in the below call. But we need to clunk fid, because we haven't
 208          * attached the fid to dentry so it won't get clunked
 209          * automatically.
 210          */
 211         p9_client_clunk(fid);
 212         deactivate_locked_super(sb);
 213         return ERR_PTR(retval);
 214 }
 215
 216 /**
 217  * v9fs_kill_super - Kill Superblock
 218  * @s: superblock
 219  *
 220  */
 221
 222 static void v9fs_kill_super(struct super_block *s)
 223 {
 224         struct v9fs_session_info *v9ses = s->s_fs_info;
 225
 226         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 227
 228         kill_anon_super(s);
 229
 230         v9fs_session_cancel(v9ses);
 231         v9fs_session_close(v9ses);
 232         kfree(v9ses);
 233         s->s_fs_info = NULL;
 234         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 235 }
 236
 237 static void
 238 v9fs_umount_begin(struct super_block *sb)
 239 {
 240         struct v9fs_session_info *v9ses;
 241
 242         v9ses = sb->s_fs_info;
 243         v9fs_session_begin_cancel(v9ses);
 244 }
 245
 246 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 247 {
 248         struct v9fs_session_info *v9ses;
 249         struct p9_fid *fid;
 250         struct p9_rstatfs rs;
 251         int res;
 252
 253         fid = v9fs_fid_lookup(dentry);
 254         if (IS_ERR(fid)) {
 255                 res = PTR_ERR(fid);
 256                 goto done;
 257         }
 258
 259         v9ses = v9fs_dentry2v9ses(dentry);
 260         if (v9fs_proto_dotl(v9ses)) {
 261                 res = p9_client_statfs(fid, &rs);
 262                 if (res == 0) {
 263                         buf->f_type = V9FS_MAGIC;
 264                         buf->f_bsize = rs.bsize;
 265                         buf->f_blocks = rs.blocks;
 266                         buf->f_bfree = rs.bfree;
 267                         buf->f_bavail = rs.bavail;
 268                         buf->f_files = rs.files;
 269                         buf->f_ffree = rs.ffree;
 270                         buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
 271                         buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
 272                         buf->f_namelen = rs.namelen;
 273                 }
 274                 if (res != -ENOSYS)
 275                         goto done;
 276         }
 277         res = simple_statfs(dentry, buf);
 278 done:
 279         return res;
 280 }
 281
 282 static int v9fs_drop_inode(struct inode *inode)
 283 {
 284         struct v9fs_session_info *v9ses;
 285         v9ses = v9fs_inode2v9ses(inode);
 286         if (v9ses->cache)
 287                 return generic_drop_inode(inode);
 288         /*
 289          * in case of non cached mode always drop the
 290          * the inode because we want the inode attribute
 291          * to always match that on the server.
 292          */
 293         return 1;
 294 }
 295
 296 static int v9fs_write_inode(struct inode *inode,
 297                             struct writeback_control *wbc)
 298 {
 299         int ret;
 300         struct p9_wstat wstat;
 301         struct v9fs_inode *v9inode;
 302         /*
 303          * send an fsync request to server irrespective of
 304          * wbc->sync_mode.
 305          */
 306         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 307         v9inode = V9FS_I(inode);
 308         if (!v9inode->writeback_fid)
 309                 return 0;
 310         v9fs_blank_wstat(&wstat);
 311
 312         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 313         if (ret < 0) {
 314                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 315                 return ret;
 316         }
 317         return 0;
 318 }
 319
 320 static int v9fs_write_inode_dotl(struct inode *inode,
 321                                  struct writeback_control *wbc)
 322 {
 323         int ret;
 324         struct v9fs_inode *v9inode;
 325         /*
 326          * send an fsync request to server irrespective of
 327          * wbc->sync_mode.
 328          */
 329         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 330         v9inode = V9FS_I(inode);
 331         if (!v9inode->writeback_fid)
 332                 return 0;
 333         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 334         if (ret < 0) {
 335                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 336                 return ret;
 337         }
 338         return 0;
 339 }
 340
 341 static const struct super_operations v9fs_super_ops = {
 342         .alloc_inode = v9fs_alloc_inode,
 343         .destroy_inode = v9fs_destroy_inode,
 344         .statfs = simple_statfs,
 345         .evict_inode = v9fs_evict_inode,
 346         .show_options = generic_show_options,
 347         .umount_begin = v9fs_umount_begin,
 348         .write_inode = v9fs_write_inode,
 349 };
 350
 351 static const struct super_operations v9fs_super_ops_dotl = {
 352         .alloc_inode = v9fs_alloc_inode,
 353         .destroy_inode = v9fs_destroy_inode,
 354         .statfs = v9fs_statfs,
 355         .drop_inode = v9fs_drop_inode,
 356         .evict_inode = v9fs_evict_inode,
 357         .show_options = generic_show_options,
 358         .umount_begin = v9fs_umount_begin,
 359         .write_inode = v9fs_write_inode_dotl,
 360 };
 361
 362 struct file_system_type v9fs_fs_type = {
 363         .name = "9p",
 364         .mount = v9fs_mount,
 365         .kill_sb = v9fs_kill_super,
 366         .owner = THIS_MODULE,
 367         .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT,
 368 };