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_SIZE;
  91
  92         sb->s_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                 goto free_session;
 134         }
 135
 136         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 137         if (IS_ERR(sb)) {
 138                 retval = PTR_ERR(sb);
 139                 goto clunk_fid;
 140         }
 141         v9fs_fill_super(sb, v9ses, flags, data);
 142
 143         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 144                 sb->s_d_op = &v9fs_cached_dentry_operations;
 145         else
 146                 sb->s_d_op = &v9fs_dentry_operations;
 147
 148         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 149         if (IS_ERR(inode)) {
 150                 retval = PTR_ERR(inode);
 151                 goto release_sb;
 152         }
 153
 154         root = d_make_root(inode);
 155         if (!root) {
 156                 retval = -ENOMEM;
 157                 goto release_sb;
 158         }
 159         sb->s_root = root;
 160         if (v9fs_proto_dotl(v9ses)) {
 161                 struct p9_stat_dotl *st = NULL;
 162                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 163                 if (IS_ERR(st)) {
 164                         retval = PTR_ERR(st);
 165                         goto release_sb;
 166                 }
 167                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 168                 v9fs_stat2inode_dotl(st, d_inode(root), 0);
 169                 kfree(st);
 170         } else {
 171                 struct p9_wstat *st = NULL;
 172                 st = p9_client_stat(fid);
 173                 if (IS_ERR(st)) {
 174                         retval = PTR_ERR(st);
 175                         goto release_sb;
 176                 }
 177
 178                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 179                 v9fs_stat2inode(st, d_inode(root), sb, 0);
 180
 181                 p9stat_free(st);
 182                 kfree(st);
 183         }
 184         retval = v9fs_get_acl(inode, fid);
 185         if (retval)
 186                 goto release_sb;
 187         v9fs_fid_add(root, fid);
 188
 189         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 190         return dget(sb->s_root);
 191
 192 clunk_fid:
 193         p9_client_clunk(fid);
 194         v9fs_session_close(v9ses);
 195 free_session:
 196         kfree(v9ses);
 197         return ERR_PTR(retval);
 198
 199 release_sb:
 200         /*
 201          * we will do the session_close and root dentry release
 202          * in the below call. But we need to clunk fid, because we haven't
 203          * attached the fid to dentry so it won't get clunked
 204          * automatically.
 205          */
 206         p9_client_clunk(fid);
 207         deactivate_locked_super(sb);
 208         return ERR_PTR(retval);
 209 }
 210
 211 /**
 212  * v9fs_kill_super - Kill Superblock
 213  * @s: superblock
 214  *
 215  */
 216
 217 static void v9fs_kill_super(struct super_block *s)
 218 {
 219         struct v9fs_session_info *v9ses = s->s_fs_info;
 220
 221         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 222
 223         kill_anon_super(s);
 224
 225         v9fs_session_cancel(v9ses);
 226         v9fs_session_close(v9ses);
 227         kfree(v9ses);
 228         s->s_fs_info = NULL;
 229         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 230 }
 231
 232 static void
 233 v9fs_umount_begin(struct super_block *sb)
 234 {
 235         struct v9fs_session_info *v9ses;
 236
 237         v9ses = sb->s_fs_info;
 238         v9fs_session_begin_cancel(v9ses);
 239 }
 240
 241 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 242 {
 243         struct v9fs_session_info *v9ses;
 244         struct p9_fid *fid;
 245         struct p9_rstatfs rs;
 246         int res;
 247
 248         fid = v9fs_fid_lookup(dentry);
 249         if (IS_ERR(fid)) {
 250                 res = PTR_ERR(fid);
 251                 goto done;
 252         }
 253
 254         v9ses = v9fs_dentry2v9ses(dentry);
 255         if (v9fs_proto_dotl(v9ses)) {
 256                 res = p9_client_statfs(fid, &rs);
 257                 if (res == 0) {
 258                         buf->f_type = rs.type;
 259                         buf->f_bsize = rs.bsize;
 260                         buf->f_blocks = rs.blocks;
 261                         buf->f_bfree = rs.bfree;
 262                         buf->f_bavail = rs.bavail;
 263                         buf->f_files = rs.files;
 264                         buf->f_ffree = rs.ffree;
 265                         buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
 266                         buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
 267                         buf->f_namelen = rs.namelen;
 268                 }
 269                 if (res != -ENOSYS)
 270                         goto done;
 271         }
 272         res = simple_statfs(dentry, buf);
 273 done:
 274         return res;
 275 }
 276
 277 static int v9fs_drop_inode(struct inode *inode)
 278 {
 279         struct v9fs_session_info *v9ses;
 280         v9ses = v9fs_inode2v9ses(inode);
 281         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 282                 return generic_drop_inode(inode);
 283         /*
 284          * in case of non cached mode always drop the
 285          * the inode because we want the inode attribute
 286          * to always match that on the server.
 287          */
 288         return 1;
 289 }
 290
 291 static int v9fs_write_inode(struct inode *inode,
 292                             struct writeback_control *wbc)
 293 {
 294         int ret;
 295         struct p9_wstat wstat;
 296         struct v9fs_inode *v9inode;
 297         /*
 298          * send an fsync request to server irrespective of
 299          * wbc->sync_mode.
 300          */
 301         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 302         v9inode = V9FS_I(inode);
 303         if (!v9inode->writeback_fid)
 304                 return 0;
 305         v9fs_blank_wstat(&wstat);
 306
 307         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 308         if (ret < 0) {
 309                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 310                 return ret;
 311         }
 312         return 0;
 313 }
 314
 315 static int v9fs_write_inode_dotl(struct inode *inode,
 316                                  struct writeback_control *wbc)
 317 {
 318         int ret;
 319         struct v9fs_inode *v9inode;
 320         /*
 321          * send an fsync request to server irrespective of
 322          * wbc->sync_mode.
 323          */
 324         v9inode = V9FS_I(inode);
 325         p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
 326                  __func__, inode, v9inode->writeback_fid);
 327         if (!v9inode->writeback_fid)
 328                 return 0;
 329
 330         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 331         if (ret < 0) {
 332                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 333                 return ret;
 334         }
 335         return 0;
 336 }
 337
 338 static const struct super_operations v9fs_super_ops = {
 339         .alloc_inode = v9fs_alloc_inode,
 340         .destroy_inode = v9fs_destroy_inode,
 341         .statfs = simple_statfs,
 342         .evict_inode = v9fs_evict_inode,
 343         .show_options = generic_show_options,
 344         .umount_begin = v9fs_umount_begin,
 345         .write_inode = v9fs_write_inode,
 346 };
 347
 348 static const struct super_operations v9fs_super_ops_dotl = {
 349         .alloc_inode = v9fs_alloc_inode,
 350         .destroy_inode = v9fs_destroy_inode,
 351         .statfs = v9fs_statfs,
 352         .drop_inode = v9fs_drop_inode,
 353         .evict_inode = v9fs_evict_inode,
 354         .show_options = generic_show_options,
 355         .umount_begin = v9fs_umount_begin,
 356         .write_inode = v9fs_write_inode_dotl,
 357 };
 358
 359 struct file_system_type v9fs_fs_type = {
 360         .name = "9p",
 361         .mount = v9fs_mount,
 362         .kill_sb = v9fs_kill_super,
 363         .owner = THIS_MODULE,
 364         .fs_flags = FS_RENAME_DOES_D_MOVE,
 365 };
 366 MODULE_ALIAS_FS("9p");