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, void *data)
  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
  75         ret = super_setup_bdi(sb);
  76         if (ret)
  77                 return ret;
  78
  79         if (v9ses->cache)
  80                 sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
  81
  82         sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
  83         if (!v9ses->cache)
  84                 sb->s_flags |= SB_SYNCHRONOUS;
  85
  86 #ifdef CONFIG_9P_FS_POSIX_ACL
  87         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
  88                 sb->s_flags |= SB_POSIXACL;
  89 #endif
  90
  91         return 0;
  92 }
  93
  94 /**
  95  * v9fs_mount - mount a superblock
  96  * @fs_type: file system type
  97  * @flags: mount flags
  98  * @dev_name: device name that was mounted
  99  * @data: mount options
 100  *
 101  */
 102
 103 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 104                        const char *dev_name, void *data)
 105 {
 106         struct super_block *sb = NULL;
 107         struct inode *inode = NULL;
 108         struct dentry *root = NULL;
 109         struct v9fs_session_info *v9ses = NULL;
 110         umode_t mode = S_IRWXUGO | S_ISVTX;
 111         struct p9_fid *fid;
 112         int retval = 0;
 113
 114         p9_debug(P9_DEBUG_VFS, "\n");
 115
 116         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 117         if (!v9ses)
 118                 return ERR_PTR(-ENOMEM);
 119
 120         fid = v9fs_session_init(v9ses, dev_name, data);
 121         if (IS_ERR(fid)) {
 122                 retval = PTR_ERR(fid);
 123                 goto free_session;
 124         }
 125
 126         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 127         if (IS_ERR(sb)) {
 128                 retval = PTR_ERR(sb);
 129                 goto clunk_fid;
 130         }
 131         retval = v9fs_fill_super(sb, v9ses, flags, data);
 132         if (retval)
 133                 goto release_sb;
 134
 135         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 136                 sb->s_d_op = &v9fs_cached_dentry_operations;
 137         else
 138                 sb->s_d_op = &v9fs_dentry_operations;
 139
 140         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 141         if (IS_ERR(inode)) {
 142                 retval = PTR_ERR(inode);
 143                 goto release_sb;
 144         }
 145
 146         root = d_make_root(inode);
 147         if (!root) {
 148                 retval = -ENOMEM;
 149                 goto release_sb;
 150         }
 151         sb->s_root = root;
 152         if (v9fs_proto_dotl(v9ses)) {
 153                 struct p9_stat_dotl *st = NULL;
 154                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 155                 if (IS_ERR(st)) {
 156                         retval = PTR_ERR(st);
 157                         goto release_sb;
 158                 }
 159                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 160                 v9fs_stat2inode_dotl(st, d_inode(root), 0);
 161                 kfree(st);
 162         } else {
 163                 struct p9_wstat *st = NULL;
 164                 st = p9_client_stat(fid);
 165                 if (IS_ERR(st)) {
 166                         retval = PTR_ERR(st);
 167                         goto release_sb;
 168                 }
 169
 170                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 171                 v9fs_stat2inode(st, d_inode(root), sb, 0);
 172
 173                 p9stat_free(st);
 174                 kfree(st);
 175         }
 176         retval = v9fs_get_acl(inode, fid);
 177         if (retval)
 178                 goto release_sb;
 179         v9fs_fid_add(root, fid);
 180
 181         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 182         return dget(sb->s_root);
 183
 184 clunk_fid:
 185         p9_client_clunk(fid);
 186         v9fs_session_close(v9ses);
 187 free_session:
 188         kfree(v9ses);
 189         return ERR_PTR(retval);
 190
 191 release_sb:
 192         /*
 193          * we will do the session_close and root dentry release
 194          * in the below call. But we need to clunk fid, because we haven't
 195          * attached the fid to dentry so it won't get clunked
 196          * automatically.
 197          */
 198         p9_client_clunk(fid);
 199         deactivate_locked_super(sb);
 200         return ERR_PTR(retval);
 201 }
 202
 203 /**
 204  * v9fs_kill_super - Kill Superblock
 205  * @s: superblock
 206  *
 207  */
 208
 209 static void v9fs_kill_super(struct super_block *s)
 210 {
 211         struct v9fs_session_info *v9ses = s->s_fs_info;
 212
 213         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 214
 215         kill_anon_super(s);
 216
 217         v9fs_session_cancel(v9ses);
 218         v9fs_session_close(v9ses);
 219         kfree(v9ses);
 220         s->s_fs_info = NULL;
 221         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 222 }
 223
 224 static void
 225 v9fs_umount_begin(struct super_block *sb)
 226 {
 227         struct v9fs_session_info *v9ses;
 228
 229         v9ses = sb->s_fs_info;
 230         v9fs_session_begin_cancel(v9ses);
 231 }
 232
 233 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 234 {
 235         struct v9fs_session_info *v9ses;
 236         struct p9_fid *fid;
 237         struct p9_rstatfs rs;
 238         int res;
 239
 240         fid = v9fs_fid_lookup(dentry);
 241         if (IS_ERR(fid)) {
 242                 res = PTR_ERR(fid);
 243                 goto done;
 244         }
 245
 246         v9ses = v9fs_dentry2v9ses(dentry);
 247         if (v9fs_proto_dotl(v9ses)) {
 248                 res = p9_client_statfs(fid, &rs);
 249                 if (res == 0) {
 250                         buf->f_type = rs.type;
 251                         buf->f_bsize = rs.bsize;
 252                         buf->f_blocks = rs.blocks;
 253                         buf->f_bfree = rs.bfree;
 254                         buf->f_bavail = rs.bavail;
 255                         buf->f_files = rs.files;
 256                         buf->f_ffree = rs.ffree;
 257                         buf->f_fsid.val[0] = rs.fsid & 0xFFFFFFFFUL;
 258                         buf->f_fsid.val[1] = (rs.fsid >> 32) & 0xFFFFFFFFUL;
 259                         buf->f_namelen = rs.namelen;
 260                 }
 261                 if (res != -ENOSYS)
 262                         goto done;
 263         }
 264         res = simple_statfs(dentry, buf);
 265 done:
 266         return res;
 267 }
 268
 269 static int v9fs_drop_inode(struct inode *inode)
 270 {
 271         struct v9fs_session_info *v9ses;
 272         v9ses = v9fs_inode2v9ses(inode);
 273         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 274                 return generic_drop_inode(inode);
 275         /*
 276          * in case of non cached mode always drop the
 277          * the inode because we want the inode attribute
 278          * to always match that on the server.
 279          */
 280         return 1;
 281 }
 282
 283 static int v9fs_write_inode(struct inode *inode,
 284                             struct writeback_control *wbc)
 285 {
 286         int ret;
 287         struct p9_wstat wstat;
 288         struct v9fs_inode *v9inode;
 289         /*
 290          * send an fsync request to server irrespective of
 291          * wbc->sync_mode.
 292          */
 293         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 294         v9inode = V9FS_I(inode);
 295         if (!v9inode->writeback_fid)
 296                 return 0;
 297         v9fs_blank_wstat(&wstat);
 298
 299         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 300         if (ret < 0) {
 301                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 302                 return ret;
 303         }
 304         return 0;
 305 }
 306
 307 static int v9fs_write_inode_dotl(struct inode *inode,
 308                                  struct writeback_control *wbc)
 309 {
 310         int ret;
 311         struct v9fs_inode *v9inode;
 312         /*
 313          * send an fsync request to server irrespective of
 314          * wbc->sync_mode.
 315          */
 316         v9inode = V9FS_I(inode);
 317         p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
 318                  __func__, inode, v9inode->writeback_fid);
 319         if (!v9inode->writeback_fid)
 320                 return 0;
 321
 322         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 323         if (ret < 0) {
 324                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 325                 return ret;
 326         }
 327         return 0;
 328 }
 329
 330 static const struct super_operations v9fs_super_ops = {
 331         .alloc_inode = v9fs_alloc_inode,
 332         .free_inode = v9fs_free_inode,
 333         .statfs = simple_statfs,
 334         .evict_inode = v9fs_evict_inode,
 335         .show_options = v9fs_show_options,
 336         .umount_begin = v9fs_umount_begin,
 337         .write_inode = v9fs_write_inode,
 338 };
 339
 340 static const struct super_operations v9fs_super_ops_dotl = {
 341         .alloc_inode = v9fs_alloc_inode,
 342         .free_inode = v9fs_free_inode,
 343         .statfs = v9fs_statfs,
 344         .drop_inode = v9fs_drop_inode,
 345         .evict_inode = v9fs_evict_inode,
 346         .show_options = v9fs_show_options,
 347         .umount_begin = v9fs_umount_begin,
 348         .write_inode = v9fs_write_inode_dotl,
 349 };
 350
 351 struct file_system_type v9fs_fs_type = {
 352         .name = "9p",
 353         .mount = v9fs_mount,
 354         .kill_sb = v9fs_kill_super,
 355         .owner = THIS_MODULE,
 356         .fs_flags = FS_RENAME_DOES_D_MOVE,
 357 };
 358 MODULE_ALIAS_FS("9p");