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/idr.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/statfs.h>
  22 #include <linux/magic.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                 sb->s_xattr = v9fs_xattr_handlers;
  68         } else {
  69                 sb->s_op = &v9fs_super_ops;
  70                 sb->s_time_max = U32_MAX;
  71         }
  72
  73         sb->s_time_min = 0;
  74
  75         ret = super_setup_bdi(sb);
  76         if (ret)
  77                 return ret;
  78
  79         if (!v9ses->cache) {
  80                 sb->s_bdi->ra_pages = 0;
  81                 sb->s_bdi->io_pages = 0;
  82         } else {
  83                 sb->s_bdi->ra_pages = v9ses->maxdata >> PAGE_SHIFT;
  84                 sb->s_bdi->io_pages = v9ses->maxdata >> PAGE_SHIFT;
  85         }
  86
  87         sb->s_flags |= SB_ACTIVE | SB_DIRSYNC;
  88         if (!v9ses->cache)
  89                 sb->s_flags |= SB_SYNCHRONOUS;
  90
  91 #ifdef CONFIG_9P_FS_POSIX_ACL
  92         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
  93                 sb->s_flags |= SB_POSIXACL;
  94 #endif
  95
  96         return 0;
  97 }
  98
  99 /**
 100  * v9fs_mount - mount a superblock
 101  * @fs_type: file system type
 102  * @flags: mount flags
 103  * @dev_name: device name that was mounted
 104  * @data: mount options
 105  *
 106  */
 107
 108 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 109                        const char *dev_name, void *data)
 110 {
 111         struct super_block *sb = NULL;
 112         struct inode *inode = NULL;
 113         struct dentry *root = NULL;
 114         struct v9fs_session_info *v9ses = NULL;
 115         umode_t mode = 0777 | S_ISVTX;
 116         struct p9_fid *fid;
 117         int retval = 0;
 118
 119         p9_debug(P9_DEBUG_VFS, "\n");
 120
 121         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 122         if (!v9ses)
 123                 return ERR_PTR(-ENOMEM);
 124
 125         fid = v9fs_session_init(v9ses, dev_name, data);
 126         if (IS_ERR(fid)) {
 127                 retval = PTR_ERR(fid);
 128                 goto free_session;
 129         }
 130
 131         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 132         if (IS_ERR(sb)) {
 133                 retval = PTR_ERR(sb);
 134                 goto clunk_fid;
 135         }
 136         retval = v9fs_fill_super(sb, v9ses, flags);
 137         if (retval)
 138                 goto release_sb;
 139
 140         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 141                 sb->s_d_op = &v9fs_cached_dentry_operations;
 142         else
 143                 sb->s_d_op = &v9fs_dentry_operations;
 144
 145         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 146         if (IS_ERR(inode)) {
 147                 retval = PTR_ERR(inode);
 148                 goto release_sb;
 149         }
 150
 151         root = d_make_root(inode);
 152         if (!root) {
 153                 retval = -ENOMEM;
 154                 goto release_sb;
 155         }
 156         sb->s_root = root;
 157         if (v9fs_proto_dotl(v9ses)) {
 158                 struct p9_stat_dotl *st = NULL;
 159
 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
 171                 st = p9_client_stat(fid);
 172                 if (IS_ERR(st)) {
 173                         retval = PTR_ERR(st);
 174                         goto release_sb;
 175                 }
 176
 177                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 178                 v9fs_stat2inode(st, d_inode(root), sb, 0);
 179
 180                 p9stat_free(st);
 181                 kfree(st);
 182         }
 183         retval = v9fs_get_acl(inode, fid);
 184         if (retval)
 185                 goto release_sb;
 186         v9fs_fid_add(root, fid);
 187
 188         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 189         return dget(sb->s_root);
 190
 191 clunk_fid:
 192         p9_client_clunk(fid);
 193         v9fs_session_close(v9ses);
 194 free_session:
 195         kfree(v9ses);
 196         return ERR_PTR(retval);
 197
 198 release_sb:
 199         /*
 200          * we will do the session_close and root dentry release
 201          * in the below call. But we need to clunk fid, because we haven't
 202          * attached the fid to dentry so it won't get clunked
 203          * automatically.
 204          */
 205         p9_client_clunk(fid);
 206         deactivate_locked_super(sb);
 207         return ERR_PTR(retval);
 208 }
 209
 210 /**
 211  * v9fs_kill_super - Kill Superblock
 212  * @s: superblock
 213  *
 214  */
 215
 216 static void v9fs_kill_super(struct super_block *s)
 217 {
 218         struct v9fs_session_info *v9ses = s->s_fs_info;
 219
 220         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 221
 222         kill_anon_super(s);
 223
 224         v9fs_session_cancel(v9ses);
 225         v9fs_session_close(v9ses);
 226         kfree(v9ses);
 227         s->s_fs_info = NULL;
 228         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 229 }
 230
 231 static void
 232 v9fs_umount_begin(struct super_block *sb)
 233 {
 234         struct v9fs_session_info *v9ses;
 235
 236         v9ses = sb->s_fs_info;
 237         v9fs_session_begin_cancel(v9ses);
 238 }
 239
 240 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 241 {
 242         struct v9fs_session_info *v9ses;
 243         struct p9_fid *fid;
 244         struct p9_rstatfs rs;
 245         int res;
 246
 247         fid = v9fs_fid_lookup(dentry);
 248         if (IS_ERR(fid)) {
 249                 res = PTR_ERR(fid);
 250                 goto done;
 251         }
 252
 253         v9ses = v9fs_dentry2v9ses(dentry);
 254         if (v9fs_proto_dotl(v9ses)) {
 255                 res = p9_client_statfs(fid, &rs);
 256                 if (res == 0) {
 257                         buf->f_type = rs.type;
 258                         buf->f_bsize = rs.bsize;
 259                         buf->f_blocks = rs.blocks;
 260                         buf->f_bfree = rs.bfree;
 261                         buf->f_bavail = rs.bavail;
 262                         buf->f_files = rs.files;
 263                         buf->f_ffree = rs.ffree;
 264                         buf->f_fsid = u64_to_fsid(rs.fsid);
 265                         buf->f_namelen = rs.namelen;
 266                 }
 267                 if (res != -ENOSYS)
 268                         goto done;
 269         }
 270         res = simple_statfs(dentry, buf);
 271 done:
 272         p9_client_clunk(fid);
 273         return res;
 274 }
 275
 276 static int v9fs_drop_inode(struct inode *inode)
 277 {
 278         struct v9fs_session_info *v9ses;
 279
 280         v9ses = v9fs_inode2v9ses(inode);
 281         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 282                 return generic_drop_inode(inode);
 283         /*
 284          * in case of non cached mode always drop the
 285          * inode because we want the inode attribute
 286          * to always match that on the server.
 287          */
 288         return 1;
 289 }
 290
 291 static int v9fs_write_inode(struct inode *inode,
 292                             struct writeback_control *wbc)
 293 {
 294         int ret;
 295         struct p9_wstat wstat;
 296         struct v9fs_inode *v9inode;
 297         /*
 298          * send an fsync request to server irrespective of
 299          * wbc->sync_mode.
 300          */
 301         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 302         v9inode = V9FS_I(inode);
 303         if (!v9inode->writeback_fid)
 304                 return 0;
 305         v9fs_blank_wstat(&wstat);
 306
 307         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 308         if (ret < 0) {
 309                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 310                 return ret;
 311         }
 312         return 0;
 313 }
 314
 315 static int v9fs_write_inode_dotl(struct inode *inode,
 316                                  struct writeback_control *wbc)
 317 {
 318         int ret;
 319         struct v9fs_inode *v9inode;
 320         /*
 321          * send an fsync request to server irrespective of
 322          * wbc->sync_mode.
 323          */
 324         v9inode = V9FS_I(inode);
 325         p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
 326                  __func__, inode, v9inode->writeback_fid);
 327         if (!v9inode->writeback_fid)
 328                 return 0;
 329
 330         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 331         if (ret < 0) {
 332                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 333                 return ret;
 334         }
 335         return 0;
 336 }
 337
 338 static const struct super_operations v9fs_super_ops = {
 339         .alloc_inode = v9fs_alloc_inode,
 340         .free_inode = v9fs_free_inode,
 341         .statfs = simple_statfs,
 342         .evict_inode = v9fs_evict_inode,
 343         .show_options = v9fs_show_options,
 344         .umount_begin = v9fs_umount_begin,
 345         .write_inode = v9fs_write_inode,
 346 };
 347
 348 static const struct super_operations v9fs_super_ops_dotl = {
 349         .alloc_inode = v9fs_alloc_inode,
 350         .free_inode = v9fs_free_inode,
 351         .statfs = v9fs_statfs,
 352         .drop_inode = v9fs_drop_inode,
 353         .evict_inode = v9fs_evict_inode,
 354         .show_options = v9fs_show_options,
 355         .umount_begin = v9fs_umount_begin,
 356         .write_inode = v9fs_write_inode_dotl,
 357 };
 358
 359 struct file_system_type v9fs_fs_type = {
 360         .name = "9p",
 361         .mount = v9fs_mount,
 362         .kill_sb = v9fs_kill_super,
 363         .owner = THIS_MODULE,
 364         .fs_flags = FS_RENAME_DOES_D_MOVE,
 365 };
 366 MODULE_ALIAS_FS("9p");