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/mount.h>
  37 #include <linux/idr.h>
  38 #include <linux/sched.h>
  39 #include <linux/slab.h>
  40 #include <linux/statfs.h>
  41 #include <linux/magic.h>
  42 #include <net/9p/9p.h>
  43 #include <net/9p/client.h>
  44
  45 #include "v9fs.h"
  46 #include "v9fs_vfs.h"
  47 #include "fid.h"
  48 #include "xattr.h"
  49 #include "acl.h"
  50
  51 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
  52
  53 /**
  54  * v9fs_set_super - set the superblock
  55  * @s: super block
  56  * @data: file system specific data
  57  *
  58  */
  59
  60 static int v9fs_set_super(struct super_block *s, void *data)
  61 {
  62         s->s_fs_info = data;
  63         return set_anon_super(s, data);
  64 }
  65
  66 /**
  67  * v9fs_fill_super - populate superblock with info
  68  * @sb: superblock
  69  * @v9ses: session information
  70  * @flags: flags propagated from v9fs_mount()
  71  *
  72  */
  73
  74 static int
  75 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  76                 int flags, void *data)
  77 {
  78         int ret;
  79
  80         sb->s_maxbytes = MAX_LFS_FILESIZE;
  81         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  82         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  83         sb->s_magic = V9FS_MAGIC;
  84         if (v9fs_proto_dotl(v9ses)) {
  85                 sb->s_op = &v9fs_super_ops_dotl;
  86                 sb->s_xattr = v9fs_xattr_handlers;
  87         } else
  88                 sb->s_op = &v9fs_super_ops;
  89
  90         ret = super_setup_bdi(sb);
  91         if (ret)
  92                 return ret;
  93
  94         if (v9ses->cache)
  95                 sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_SIZE;
  96
  97         sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
  98         if (!v9ses->cache)
  99                 sb->s_flags |= SB_SYNCHRONOUS;
 100
 101 #ifdef CONFIG_9P_FS_POSIX_ACL
 102         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
 103                 sb->s_flags |= SB_POSIXACL;
 104 #endif
 105
 106         return 0;
 107 }
 108
 109 /**
 110  * v9fs_mount - mount a superblock
 111  * @fs_type: file system type
 112  * @flags: mount flags
 113  * @dev_name: device name that was mounted
 114  * @data: mount options
 115  *
 116  */
 117
 118 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 119                        const char *dev_name, void *data)
 120 {
 121         struct super_block *sb = NULL;
 122         struct inode *inode = NULL;
 123         struct dentry *root = NULL;
 124         struct v9fs_session_info *v9ses = NULL;
 125         umode_t mode = S_IRWXUGO | S_ISVTX;
 126         struct p9_fid *fid;
 127         int retval = 0;
 128
 129         p9_debug(P9_DEBUG_VFS, "\n");
 130
 131         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 132         if (!v9ses)
 133                 return ERR_PTR(-ENOMEM);
 134
 135         fid = v9fs_session_init(v9ses, dev_name, data);
 136         if (IS_ERR(fid)) {
 137                 retval = PTR_ERR(fid);
 138                 goto free_session;
 139         }
 140
 141         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 142         if (IS_ERR(sb)) {
 143                 retval = PTR_ERR(sb);
 144                 goto clunk_fid;
 145         }
 146         retval = v9fs_fill_super(sb, v9ses, flags, data);
 147         if (retval)
 148                 goto release_sb;
 149
 150         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 151                 sb->s_d_op = &v9fs_cached_dentry_operations;
 152         else
 153                 sb->s_d_op = &v9fs_dentry_operations;
 154
 155         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 156         if (IS_ERR(inode)) {
 157                 retval = PTR_ERR(inode);
 158                 goto release_sb;
 159         }
 160
 161         root = d_make_root(inode);
 162         if (!root) {
 163                 retval = -ENOMEM;
 164                 goto release_sb;
 165         }
 166         sb->s_root = root;
 167         if (v9fs_proto_dotl(v9ses)) {
 168                 struct p9_stat_dotl *st = NULL;
 169                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 170                 if (IS_ERR(st)) {
 171                         retval = PTR_ERR(st);
 172                         goto release_sb;
 173                 }
 174                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 175                 v9fs_stat2inode_dotl(st, d_inode(root), 0);
 176                 kfree(st);
 177         } else {
 178                 struct p9_wstat *st = NULL;
 179                 st = p9_client_stat(fid);
 180                 if (IS_ERR(st)) {
 181                         retval = PTR_ERR(st);
 182                         goto release_sb;
 183                 }
 184
 185                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 186                 v9fs_stat2inode(st, d_inode(root), sb, 0);
 187
 188                 p9stat_free(st);
 189                 kfree(st);
 190         }
 191         retval = v9fs_get_acl(inode, fid);
 192         if (retval)
 193                 goto release_sb;
 194         v9fs_fid_add(root, fid);
 195
 196         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 197         return dget(sb->s_root);
 198
 199 clunk_fid:
 200         p9_client_clunk(fid);
 201         v9fs_session_close(v9ses);
 202 free_session:
 203         kfree(v9ses);
 204         return ERR_PTR(retval);
 205
 206 release_sb:
 207         /*
 208          * we will do the session_close and root dentry release
 209          * in the below call. But we need to clunk fid, because we haven't
 210          * attached the fid to dentry so it won't get clunked
 211          * automatically.
 212          */
 213         p9_client_clunk(fid);
 214         deactivate_locked_super(sb);
 215         return ERR_PTR(retval);
 216 }
 217
 218 /**
 219  * v9fs_kill_super - Kill Superblock
 220  * @s: superblock
 221  *
 222  */
 223
 224 static void v9fs_kill_super(struct super_block *s)
 225 {
 226         struct v9fs_session_info *v9ses = s->s_fs_info;
 227
 228         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 229
 230         kill_anon_super(s);
 231
 232         v9fs_session_cancel(v9ses);
 233         v9fs_session_close(v9ses);
 234         kfree(v9ses);
 235         s->s_fs_info = NULL;
 236         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 237 }
 238
 239 static void
 240 v9fs_umount_begin(struct super_block *sb)
 241 {
 242         struct v9fs_session_info *v9ses;
 243
 244         v9ses = sb->s_fs_info;
 245         v9fs_session_begin_cancel(v9ses);
 246 }
 247
 248 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 249 {
 250         struct v9fs_session_info *v9ses;
 251         struct p9_fid *fid;
 252         struct p9_rstatfs rs;
 253         int res;
 254
 255         fid = v9fs_fid_lookup(dentry);
 256         if (IS_ERR(fid)) {
 257                 res = PTR_ERR(fid);
 258                 goto done;
 259         }
 260
 261         v9ses = v9fs_dentry2v9ses(dentry);
 262         if (v9fs_proto_dotl(v9ses)) {
 263                 res = p9_client_statfs(fid, &rs);
 264                 if (res == 0) {
 265                         buf->f_type = rs.type;
 266                         buf->f_bsize = rs.bsize;
 267                         buf->f_blocks = rs.blocks;
 268                         buf->f_bfree = rs.bfree;
 269                         buf->f_bavail = rs.bavail;
 270                         buf->f_files = rs.files;
 271                         buf->f_ffree = rs.ffree;
 272                         buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
 273                         buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
 274                         buf->f_namelen = rs.namelen;
 275                 }
 276                 if (res != -ENOSYS)
 277                         goto done;
 278         }
 279         res = simple_statfs(dentry, buf);
 280 done:
 281         return res;
 282 }
 283
 284 static int v9fs_drop_inode(struct inode *inode)
 285 {
 286         struct v9fs_session_info *v9ses;
 287         v9ses = v9fs_inode2v9ses(inode);
 288         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 289                 return generic_drop_inode(inode);
 290         /*
 291          * in case of non cached mode always drop the
 292          * the inode because we want the inode attribute
 293          * to always match that on the server.
 294          */
 295         return 1;
 296 }
 297
 298 static int v9fs_write_inode(struct inode *inode,
 299                             struct writeback_control *wbc)
 300 {
 301         int ret;
 302         struct p9_wstat wstat;
 303         struct v9fs_inode *v9inode;
 304         /*
 305          * send an fsync request to server irrespective of
 306          * wbc->sync_mode.
 307          */
 308         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 309         v9inode = V9FS_I(inode);
 310         if (!v9inode->writeback_fid)
 311                 return 0;
 312         v9fs_blank_wstat(&wstat);
 313
 314         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 315         if (ret < 0) {
 316                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 317                 return ret;
 318         }
 319         return 0;
 320 }
 321
 322 static int v9fs_write_inode_dotl(struct inode *inode,
 323                                  struct writeback_control *wbc)
 324 {
 325         int ret;
 326         struct v9fs_inode *v9inode;
 327         /*
 328          * send an fsync request to server irrespective of
 329          * wbc->sync_mode.
 330          */
 331         v9inode = V9FS_I(inode);
 332         p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
 333                  __func__, inode, v9inode->writeback_fid);
 334         if (!v9inode->writeback_fid)
 335                 return 0;
 336
 337         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 338         if (ret < 0) {
 339                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 340                 return ret;
 341         }
 342         return 0;
 343 }
 344
 345 static const struct super_operations v9fs_super_ops = {
 346         .alloc_inode = v9fs_alloc_inode,
 347         .destroy_inode = v9fs_destroy_inode,
 348         .statfs = simple_statfs,
 349         .evict_inode = v9fs_evict_inode,
 350         .show_options = v9fs_show_options,
 351         .umount_begin = v9fs_umount_begin,
 352         .write_inode = v9fs_write_inode,
 353 };
 354
 355 static const struct super_operations v9fs_super_ops_dotl = {
 356         .alloc_inode = v9fs_alloc_inode,
 357         .destroy_inode = v9fs_destroy_inode,
 358         .statfs = v9fs_statfs,
 359         .drop_inode = v9fs_drop_inode,
 360         .evict_inode = v9fs_evict_inode,
 361         .show_options = v9fs_show_options,
 362         .umount_begin = v9fs_umount_begin,
 363         .write_inode = v9fs_write_inode_dotl,
 364 };
 365
 366 struct file_system_type v9fs_fs_type = {
 367         .name = "9p",
 368         .mount = v9fs_mount,
 369         .kill_sb = v9fs_kill_super,
 370         .owner = THIS_MODULE,
 371         .fs_flags = FS_RENAME_DOES_D_MOVE,
 372 };
 373 MODULE_ALIAS_FS("9p");