fs/9p/vfs_super.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/9p/vfs_super.c
   4  *
   5  * This file contians superblock ops for 9P2000. It is intended that
   6  * you mount this file system on directories.
   7  *
   8  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   9  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/errno.h>
  15 #include <linux/fs.h>
  16 #include <linux/file.h>
  17 #include <linux/stat.h>
  18 #include <linux/string.h>
  19 #include <linux/inet.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/mount.h>
  22 #include <linux/idr.h>
  23 #include <linux/sched.h>
  24 #include <linux/slab.h>
  25 #include <linux/statfs.h>
  26 #include <linux/magic.h>
  27 #include <net/9p/9p.h>
  28 #include <net/9p/client.h>
  29
  30 #include "v9fs.h"
  31 #include "v9fs_vfs.h"
  32 #include "fid.h"
  33 #include "xattr.h"
  34 #include "acl.h"
  35
  36 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
  37
  38 /**
  39  * v9fs_set_super - set the superblock
  40  * @s: super block
  41  * @data: file system specific data
  42  *
  43  */
  44
  45 static int v9fs_set_super(struct super_block *s, void *data)
  46 {
  47         s->s_fs_info = data;
  48         return set_anon_super(s, data);
  49 }
  50
  51 /**
  52  * v9fs_fill_super - populate superblock with info
  53  * @sb: superblock
  54  * @v9ses: session information
  55  * @flags: flags propagated from v9fs_mount()
  56  *
  57  */
  58
  59 static int
  60 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  61                 int flags)
  62 {
  63         int ret;
  64
  65         sb->s_maxbytes = MAX_LFS_FILESIZE;
  66         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  67         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  68         sb->s_magic = V9FS_MAGIC;
  69         if (v9fs_proto_dotl(v9ses)) {
  70                 sb->s_op = &v9fs_super_ops_dotl;
  71                 sb->s_xattr = v9fs_xattr_handlers;
  72         } else {
  73                 sb->s_op = &v9fs_super_ops;
  74                 sb->s_time_max = U32_MAX;
  75         }
  76
  77         sb->s_time_min = 0;
  78
  79         ret = super_setup_bdi(sb);
  80         if (ret)
  81                 return ret;
  82
  83         if (!v9ses->cache) {
  84                 sb->s_bdi->ra_pages = 0;
  85                 sb->s_bdi->io_pages = 0;
  86         }
  87
  88         sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
  89         if (!v9ses->cache)
  90                 sb->s_flags |= SB_SYNCHRONOUS;
  91
  92 #ifdef CONFIG_9P_FS_POSIX_ACL
  93         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
  94                 sb->s_flags |= SB_POSIXACL;
  95 #endif
  96
  97         return 0;
  98 }
  99
 100 /**
 101  * v9fs_mount - mount a superblock
 102  * @fs_type: file system type
 103  * @flags: mount flags
 104  * @dev_name: device name that was mounted
 105  * @data: mount options
 106  *
 107  */
 108
 109 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 110                        const char *dev_name, void *data)
 111 {
 112         struct super_block *sb = NULL;
 113         struct inode *inode = NULL;
 114         struct dentry *root = NULL;
 115         struct v9fs_session_info *v9ses = NULL;
 116         umode_t mode = S_IRWXUGO | S_ISVTX;
 117         struct p9_fid *fid;
 118         int retval = 0;
 119
 120         p9_debug(P9_DEBUG_VFS, "\n");
 121
 122         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 123         if (!v9ses)
 124                 return ERR_PTR(-ENOMEM);
 125
 126         fid = v9fs_session_init(v9ses, dev_name, data);
 127         if (IS_ERR(fid)) {
 128                 retval = PTR_ERR(fid);
 129                 goto free_session;
 130         }
 131
 132         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 133         if (IS_ERR(sb)) {
 134                 retval = PTR_ERR(sb);
 135                 goto clunk_fid;
 136         }
 137         retval = v9fs_fill_super(sb, v9ses, flags);
 138         if (retval)
 139                 goto release_sb;
 140
 141         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 142                 sb->s_d_op = &v9fs_cached_dentry_operations;
 143         else
 144                 sb->s_d_op = &v9fs_dentry_operations;
 145
 146         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 147         if (IS_ERR(inode)) {
 148                 retval = PTR_ERR(inode);
 149                 goto release_sb;
 150         }
 151
 152         root = d_make_root(inode);
 153         if (!root) {
 154                 retval = -ENOMEM;
 155                 goto release_sb;
 156         }
 157         sb->s_root = root;
 158         if (v9fs_proto_dotl(v9ses)) {
 159                 struct p9_stat_dotl *st = NULL;
 160                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 161                 if (IS_ERR(st)) {
 162                         retval = PTR_ERR(st);
 163                         goto release_sb;
 164                 }
 165                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 166                 v9fs_stat2inode_dotl(st, d_inode(root), 0);
 167                 kfree(st);
 168         } else {
 169                 struct p9_wstat *st = NULL;
 170                 st = p9_client_stat(fid);
 171                 if (IS_ERR(st)) {
 172                         retval = PTR_ERR(st);
 173                         goto release_sb;
 174                 }
 175
 176                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 177                 v9fs_stat2inode(st, d_inode(root), sb, 0);
 178
 179                 p9stat_free(st);
 180                 kfree(st);
 181         }
 182         retval = v9fs_get_acl(inode, fid);
 183         if (retval)
 184                 goto release_sb;
 185         v9fs_fid_add(root, fid);
 186
 187         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 188         return dget(sb->s_root);
 189
 190 clunk_fid:
 191         p9_client_clunk(fid);
 192         v9fs_session_close(v9ses);
 193 free_session:
 194         kfree(v9ses);
 195         return ERR_PTR(retval);
 196
 197 release_sb:
 198         /*
 199          * we will do the session_close and root dentry release
 200          * in the below call. But we need to clunk fid, because we haven't
 201          * attached the fid to dentry so it won't get clunked
 202          * automatically.
 203          */
 204         p9_client_clunk(fid);
 205         deactivate_locked_super(sb);
 206         return ERR_PTR(retval);
 207 }
 208
 209 /**
 210  * v9fs_kill_super - Kill Superblock
 211  * @s: superblock
 212  *
 213  */
 214
 215 static void v9fs_kill_super(struct super_block *s)
 216 {
 217         struct v9fs_session_info *v9ses = s->s_fs_info;
 218
 219         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 220
 221         kill_anon_super(s);
 222
 223         v9fs_session_cancel(v9ses);
 224         v9fs_session_close(v9ses);
 225         kfree(v9ses);
 226         s->s_fs_info = NULL;
 227         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 228 }
 229
 230 static void
 231 v9fs_umount_begin(struct super_block *sb)
 232 {
 233         struct v9fs_session_info *v9ses;
 234
 235         v9ses = sb->s_fs_info;
 236         v9fs_session_begin_cancel(v9ses);
 237 }
 238
 239 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 240 {
 241         struct v9fs_session_info *v9ses;
 242         struct p9_fid *fid;
 243         struct p9_rstatfs rs;
 244         int res;
 245
 246         fid = v9fs_fid_lookup(dentry);
 247         if (IS_ERR(fid)) {
 248                 res = PTR_ERR(fid);
 249                 goto done;
 250         }
 251
 252         v9ses = v9fs_dentry2v9ses(dentry);
 253         if (v9fs_proto_dotl(v9ses)) {
 254                 res = p9_client_statfs(fid, &rs);
 255                 if (res == 0) {
 256                         buf->f_type = rs.type;
 257                         buf->f_bsize = rs.bsize;
 258                         buf->f_blocks = rs.blocks;
 259                         buf->f_bfree = rs.bfree;
 260                         buf->f_bavail = rs.bavail;
 261                         buf->f_files = rs.files;
 262                         buf->f_ffree = rs.ffree;
 263                         buf->f_fsid = u64_to_fsid(rs.fsid);
 264                         buf->f_namelen = rs.namelen;
 265                 }
 266                 if (res != -ENOSYS)
 267                         goto done;
 268         }
 269         res = simple_statfs(dentry, buf);
 270 done:
 271         return res;
 272 }
 273
 274 static int v9fs_drop_inode(struct inode *inode)
 275 {
 276         struct v9fs_session_info *v9ses;
 277         v9ses = v9fs_inode2v9ses(inode);
 278         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 279                 return generic_drop_inode(inode);
 280         /*
 281          * in case of non cached mode always drop the
 282          * the inode because we want the inode attribute
 283          * to always match that on the server.
 284          */
 285         return 1;
 286 }
 287
 288 static int v9fs_write_inode(struct inode *inode,
 289                             struct writeback_control *wbc)
 290 {
 291         int ret;
 292         struct p9_wstat wstat;
 293         struct v9fs_inode *v9inode;
 294         /*
 295          * send an fsync request to server irrespective of
 296          * wbc->sync_mode.
 297          */
 298         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 299         v9inode = V9FS_I(inode);
 300         if (!v9inode->writeback_fid)
 301                 return 0;
 302         v9fs_blank_wstat(&wstat);
 303
 304         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 305         if (ret < 0) {
 306                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 307                 return ret;
 308         }
 309         return 0;
 310 }
 311
 312 static int v9fs_write_inode_dotl(struct inode *inode,
 313                                  struct writeback_control *wbc)
 314 {
 315         int ret;
 316         struct v9fs_inode *v9inode;
 317         /*
 318          * send an fsync request to server irrespective of
 319          * wbc->sync_mode.
 320          */
 321         v9inode = V9FS_I(inode);
 322         p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
 323                  __func__, inode, v9inode->writeback_fid);
 324         if (!v9inode->writeback_fid)
 325                 return 0;
 326
 327         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 328         if (ret < 0) {
 329                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 330                 return ret;
 331         }
 332         return 0;
 333 }
 334
 335 static const struct super_operations v9fs_super_ops = {
 336         .alloc_inode = v9fs_alloc_inode,
 337         .free_inode = v9fs_free_inode,
 338         .statfs = simple_statfs,
 339         .evict_inode = v9fs_evict_inode,
 340         .show_options = v9fs_show_options,
 341         .umount_begin = v9fs_umount_begin,
 342         .write_inode = v9fs_write_inode,
 343 };
 344
 345 static const struct super_operations v9fs_super_ops_dotl = {
 346         .alloc_inode = v9fs_alloc_inode,
 347         .free_inode = v9fs_free_inode,
 348         .statfs = v9fs_statfs,
 349         .drop_inode = v9fs_drop_inode,
 350         .evict_inode = v9fs_evict_inode,
 351         .show_options = v9fs_show_options,
 352         .umount_begin = v9fs_umount_begin,
 353         .write_inode = v9fs_write_inode_dotl,
 354 };
 355
 356 struct file_system_type v9fs_fs_type = {
 357         .name = "9p",
 358         .mount = v9fs_mount,
 359         .kill_sb = v9fs_kill_super,
 360         .owner = THIS_MODULE,
 361         .fs_flags = FS_RENAME_DOES_D_MOVE,
 362 };
 363 MODULE_ALIAS_FS("9p");