LXR linux/fs/9p/vfs

   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
  52static 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
  61static 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
  75static void
  76v9fs_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 |= 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
 113static 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, flags, 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_make_root(inode);
 159        if (!root) {
 160                retval = -ENOMEM;
 161                goto release_sb;
 162        }
 163        sb->s_root = root;
 164        if (v9fs_proto_dotl(v9ses)) {
 165                struct p9_stat_dotl *st = NULL;
 166                st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 167                if (IS_ERR(st)) {
 168                        retval = PTR_ERR(st);
 169                        goto release_sb;
 170                }
 171                root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 172                v9fs_stat2inode_dotl(st, root->d_inode);
 173                kfree(st);
 174        } else {
 175                struct p9_wstat *st = NULL;
 176                st = p9_client_stat(fid);
 177                if (IS_ERR(st)) {
 178                        retval = PTR_ERR(st);
 179                        goto release_sb;
 180                }
 181
 182                root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 183                v9fs_stat2inode(st, root->d_inode, sb);
 184
 185                p9stat_free(st);
 186                kfree(st);
 187        }
 188        retval = v9fs_get_acl(inode, fid);
 189        if (retval)
 190                goto release_sb;
 191        v9fs_fid_add(root, fid);
 192
 193        p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 194        return dget(sb->s_root);
 195
 196clunk_fid:
 197        p9_client_clunk(fid);
 198close_session:
 199        v9fs_session_close(v9ses);
 200        kfree(v9ses);
 201        return ERR_PTR(retval);
 202
 203release_sb:
 204        /*
 205         * we will do the session_close and root dentry release
 206         * in the below call. But we need to clunk fid, because we haven't
 207         * attached the fid to dentry so it won't get clunked
 208         * automatically.
 209         */
 210        p9_client_clunk(fid);
 211        deactivate_locked_super(sb);
 212        return ERR_PTR(retval);
 213}
 214
 215/**
 216 * v9fs_kill_super - Kill Superblock
 217 * @s: superblock
 218 *
 219 */
 220
 221static void v9fs_kill_super(struct super_block *s)
 222{
 223        struct v9fs_session_info *v9ses = s->s_fs_info;
 224
 225        p9_debug(P9_DEBUG_VFS, " %p\n", s);
 226
 227        kill_anon_super(s);
 228
 229        v9fs_session_cancel(v9ses);
 230        v9fs_session_close(v9ses);
 231        kfree(v9ses);
 232        s->s_fs_info = NULL;
 233        p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 234}
 235
 236static void
 237v9fs_umount_begin(struct super_block *sb)
 238{
 239        struct v9fs_session_info *v9ses;
 240
 241        v9ses = sb->s_fs_info;
 242        v9fs_session_begin_cancel(v9ses);
 243}
 244
 245static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 246{
 247        struct v9fs_session_info *v9ses;
 248        struct p9_fid *fid;
 249        struct p9_rstatfs rs;
 250        int res;
 251
 252        fid = v9fs_fid_lookup(dentry);
 253        if (IS_ERR(fid)) {
 254                res = PTR_ERR(fid);
 255                goto done;
 256        }
 257
 258        v9ses = v9fs_dentry2v9ses(dentry);
 259        if (v9fs_proto_dotl(v9ses)) {
 260                res = p9_client_statfs(fid, &rs);
 261                if (res == 0) {
 262                        buf->f_type = rs.type;
 263                        buf->f_bsize = rs.bsize;
 264                        buf->f_blocks = rs.blocks;
 265                        buf->f_bfree = rs.bfree;
 266                        buf->f_bavail = rs.bavail;
 267                        buf->f_files = rs.files;
 268                        buf->f_ffree = rs.ffree;
 269                        buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
 270                        buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
 271                        buf->f_namelen = rs.namelen;
 272                }
 273                if (res != -ENOSYS)
 274                        goto done;
 275        }
 276        res = simple_statfs(dentry, buf);
 277done:
 278        return res;
 279}
 280
 281static int v9fs_drop_inode(struct inode *inode)
 282{
 283        struct v9fs_session_info *v9ses;
 284        v9ses = v9fs_inode2v9ses(inode);
 285        if (v9ses->cache)
 286                return generic_drop_inode(inode);
 287        /*
 288         * in case of non cached mode always drop the
 289         * the inode because we want the inode attribute
 290         * to always match that on the server.
 291         */
 292        return 1;
 293}
 294
 295static int v9fs_write_inode(struct inode *inode,
 296                            struct writeback_control *wbc)
 297{
 298        int ret;
 299        struct p9_wstat wstat;
 300        struct v9fs_inode *v9inode;
 301        /*
 302         * send an fsync request to server irrespective of
 303         * wbc->sync_mode.
 304         */
 305        p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 306        v9inode = V9FS_I(inode);
 307        if (!v9inode->writeback_fid)
 308                return 0;
 309        v9fs_blank_wstat(&wstat);
 310
 311        ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 312        if (ret < 0) {
 313                __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 314                return ret;
 315        }
 316        return 0;
 317}
 318
 319static int v9fs_write_inode_dotl(struct inode *inode,
 320                                 struct writeback_control *wbc)
 321{
 322        int ret;
 323        struct v9fs_inode *v9inode;
 324        /*
 325         * send an fsync request to server irrespective of
 326         * wbc->sync_mode.
 327         */
 328        p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 329        v9inode = V9FS_I(inode);
 330        if (!v9inode->writeback_fid)
 331                return 0;
 332        ret = p9_client_fsync(v9inode->writeback_fid, 0);
 333        if (ret < 0) {
 334                __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 335                return ret;
 336        }
 337        return 0;
 338}
 339
 340static const struct super_operations v9fs_super_ops = {
 341        .alloc_inode = v9fs_alloc_inode,
 342        .destroy_inode = v9fs_destroy_inode,
 343        .statfs = simple_statfs,
 344        .evict_inode = v9fs_evict_inode,
 345        .show_options = generic_show_options,
 346        .umount_begin = v9fs_umount_begin,
 347        .write_inode = v9fs_write_inode,
 348};
 349
 350static const struct super_operations v9fs_super_ops_dotl = {
 351        .alloc_inode = v9fs_alloc_inode,
 352        .destroy_inode = v9fs_destroy_inode,
 353        .statfs = v9fs_statfs,
 354        .drop_inode = v9fs_drop_inode,
 355        .evict_inode = v9fs_evict_inode,
 356        .show_options = generic_show_options,
 357        .umount_begin = v9fs_umount_begin,
 358        .write_inode = v9fs_write_inode_dotl,
 359};
 360
 361struct file_system_type v9fs_fs_type = {
 362        .name = "9p",
 363        .mount = v9fs_mount,
 364        .kill_sb = v9fs_kill_super,
 365        .owner = THIS_MODULE,
 366        .fs_flags = FS_RENAME_DOES_D_MOVE,
 367};
 368MODULE_ALIAS_FS("9p");
 369