fs/9p/vfs_super.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   5  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/file.h>
  13 #include <linux/stat.h>
  14 #include <linux/string.h>
  15 #include <linux/inet.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/mount.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/statfs.h>
  21 #include <linux/magic.h>
  22 #include <linux/fscache.h>
  23 #include <net/9p/9p.h>
  24 #include <net/9p/client.h>
  25
  26 #include "v9fs.h"
  27 #include "v9fs_vfs.h"
  28 #include "fid.h"
  29 #include "xattr.h"
  30 #include "acl.h"
  31
  32 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
  33
  34 /**
  35  * v9fs_set_super - set the superblock
  36  * @s: super block
  37  * @data: file system specific data
  38  *
  39  */
  40
  41 static int v9fs_set_super(struct super_block *s, void *data)
  42 {
  43         s->s_fs_info = data;
  44         return set_anon_super(s, data);
  45 }
  46
  47 /**
  48  * v9fs_fill_super - populate superblock with info
  49  * @sb: superblock
  50  * @v9ses: session information
  51  * @flags: flags propagated from v9fs_mount()
  52  *
  53  */
  54
  55 static int
  56 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  57                 int flags)
  58 {
  59         int ret;
  60
  61         sb->s_maxbytes = MAX_LFS_FILESIZE;
  62         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  63         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  64         sb->s_magic = V9FS_MAGIC;
  65         if (v9fs_proto_dotl(v9ses)) {
  66                 sb->s_op = &v9fs_super_ops_dotl;
  67                 if (!(v9ses->flags & V9FS_NO_XATTR))
  68                         sb->s_xattr = v9fs_xattr_handlers;
  69         } else {
  70                 sb->s_op = &v9fs_super_ops;
  71                 sb->s_time_max = U32_MAX;
  72         }
  73
  74         sb->s_time_min = 0;
  75
  76         ret = super_setup_bdi(sb);
  77         if (ret)
  78                 return ret;
  79
  80         if (!v9ses->cache) {
  81                 sb->s_bdi->ra_pages = 0;
  82                 sb->s_bdi->io_pages = 0;
  83         } else {
  84                 sb->s_bdi->ra_pages = v9ses->maxdata >> PAGE_SHIFT;
  85                 sb->s_bdi->io_pages = v9ses->maxdata >> PAGE_SHIFT;
  86         }
  87
  88         sb->s_flags |= SB_ACTIVE;
  89
  90 #ifdef CONFIG_9P_FS_POSIX_ACL
  91         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
  92                 sb->s_flags |= SB_POSIXACL;
  93 #endif
  94
  95         return 0;
  96 }
  97
  98 /**
  99  * v9fs_mount - mount a superblock
 100  * @fs_type: file system type
 101  * @flags: mount flags
 102  * @dev_name: device name that was mounted
 103  * @data: mount options
 104  *
 105  */
 106
 107 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 108                        const char *dev_name, void *data)
 109 {
 110         struct super_block *sb = NULL;
 111         struct inode *inode = NULL;
 112         struct dentry *root = NULL;
 113         struct v9fs_session_info *v9ses = NULL;
 114         umode_t mode = 0777 | S_ISVTX;
 115         struct p9_fid *fid;
 116         int retval = 0;
 117
 118         p9_debug(P9_DEBUG_VFS, "\n");
 119
 120         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 121         if (!v9ses)
 122                 return ERR_PTR(-ENOMEM);
 123
 124         fid = v9fs_session_init(v9ses, dev_name, data);
 125         if (IS_ERR(fid)) {
 126                 retval = PTR_ERR(fid);
 127                 goto free_session;
 128         }
 129
 130         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 131         if (IS_ERR(sb)) {
 132                 retval = PTR_ERR(sb);
 133                 goto clunk_fid;
 134         }
 135         retval = v9fs_fill_super(sb, v9ses, flags);
 136         if (retval)
 137                 goto release_sb;
 138
 139         if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 140                 sb->s_d_op = &v9fs_cached_dentry_operations;
 141         else
 142                 sb->s_d_op = &v9fs_dentry_operations;
 143
 144         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 145         if (IS_ERR(inode)) {
 146                 retval = PTR_ERR(inode);
 147                 goto release_sb;
 148         }
 149
 150         root = d_make_root(inode);
 151         if (!root) {
 152                 retval = -ENOMEM;
 153                 goto release_sb;
 154         }
 155         sb->s_root = root;
 156         if (v9fs_proto_dotl(v9ses)) {
 157                 struct p9_stat_dotl *st = NULL;
 158
 159                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 160                 if (IS_ERR(st)) {
 161                         retval = PTR_ERR(st);
 162                         goto release_sb;
 163                 }
 164                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 165                 v9fs_stat2inode_dotl(st, d_inode(root), 0);
 166                 kfree(st);
 167         } else {
 168                 struct p9_wstat *st = NULL;
 169
 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_fid_put(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_fid_put(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         p9_fid_put(fid);
 272         return res;
 273 }
 274
 275 static int v9fs_drop_inode(struct inode *inode)
 276 {
 277         struct v9fs_session_info *v9ses;
 278
 279         v9ses = v9fs_inode2v9ses(inode);
 280         if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 281                 return generic_drop_inode(inode);
 282         /*
 283          * in case of non cached mode always drop the
 284          * inode because we want the inode attribute
 285          * to always match that on the server.
 286          */
 287         return 1;
 288 }
 289
 290 static int v9fs_write_inode(struct inode *inode,
 291                             struct writeback_control *wbc)
 292 {
 293         struct v9fs_inode *v9inode;
 294
 295         /*
 296          * send an fsync request to server irrespective of
 297          * wbc->sync_mode.
 298          */
 299         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 300
 301         v9inode = V9FS_I(inode);
 302         fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
 303
 304         return 0;
 305 }
 306
 307 static int v9fs_write_inode_dotl(struct inode *inode,
 308                                  struct writeback_control *wbc)
 309 {
 310         struct v9fs_inode *v9inode;
 311
 312         v9inode = V9FS_I(inode);
 313         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 314
 315         fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
 316
 317         return 0;
 318 }
 319
 320 static const struct super_operations v9fs_super_ops = {
 321         .alloc_inode = v9fs_alloc_inode,
 322         .free_inode = v9fs_free_inode,
 323         .statfs = simple_statfs,
 324         .evict_inode = v9fs_evict_inode,
 325         .show_options = v9fs_show_options,
 326         .umount_begin = v9fs_umount_begin,
 327         .write_inode = v9fs_write_inode,
 328 };
 329
 330 static const struct super_operations v9fs_super_ops_dotl = {
 331         .alloc_inode = v9fs_alloc_inode,
 332         .free_inode = v9fs_free_inode,
 333         .statfs = v9fs_statfs,
 334         .drop_inode = v9fs_drop_inode,
 335         .evict_inode = v9fs_evict_inode,
 336         .show_options = v9fs_show_options,
 337         .umount_begin = v9fs_umount_begin,
 338         .write_inode = v9fs_write_inode_dotl,
 339 };
 340
 341 struct file_system_type v9fs_fs_type = {
 342         .name = "9p",
 343         .mount = v9fs_mount,
 344         .kill_sb = v9fs_kill_super,
 345         .owner = THIS_MODULE,
 346         .fs_flags = FS_RENAME_DOES_D_MOVE,
 347 };
 348 MODULE_ALIAS_FS("9p");