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 <linux/fscache.h>
  24 #include <net/9p/9p.h>
  25 #include <net/9p/client.h>
  26
  27 #include "v9fs.h"
  28 #include "v9fs_vfs.h"
  29 #include "fid.h"
  30 #include "xattr.h"
  31 #include "acl.h"
  32
  33 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
  34
  35 /**
  36  * v9fs_set_super - set the superblock
  37  * @s: super block
  38  * @data: file system specific data
  39  *
  40  */
  41
  42 static int v9fs_set_super(struct super_block *s, void *data)
  43 {
  44         s->s_fs_info = data;
  45         return set_anon_super(s, data);
  46 }
  47
  48 /**
  49  * v9fs_fill_super - populate superblock with info
  50  * @sb: superblock
  51  * @v9ses: session information
  52  * @flags: flags propagated from v9fs_mount()
  53  *
  54  */
  55
  56 static int
  57 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  58                 int flags)
  59 {
  60         int ret;
  61
  62         sb->s_maxbytes = MAX_LFS_FILESIZE;
  63         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  64         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  65         sb->s_magic = V9FS_MAGIC;
  66         if (v9fs_proto_dotl(v9ses)) {
  67                 sb->s_op = &v9fs_super_ops_dotl;
  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 | 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 = 0777 | 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
 161                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 162                 if (IS_ERR(st)) {
 163                         retval = PTR_ERR(st);
 164                         goto release_sb;
 165                 }
 166                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 167                 v9fs_stat2inode_dotl(st, d_inode(root), 0);
 168                 kfree(st);
 169         } else {
 170                 struct p9_wstat *st = NULL;
 171
 172                 st = p9_client_stat(fid);
 173                 if (IS_ERR(st)) {
 174                         retval = PTR_ERR(st);
 175                         goto release_sb;
 176                 }
 177
 178                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 179                 v9fs_stat2inode(st, d_inode(root), sb, 0);
 180
 181                 p9stat_free(st);
 182                 kfree(st);
 183         }
 184         retval = v9fs_get_acl(inode, fid);
 185         if (retval)
 186                 goto release_sb;
 187         v9fs_fid_add(root, &fid);
 188
 189         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 190         return dget(sb->s_root);
 191
 192 clunk_fid:
 193         p9_fid_put(fid);
 194         v9fs_session_close(v9ses);
 195 free_session:
 196         kfree(v9ses);
 197         return ERR_PTR(retval);
 198
 199 release_sb:
 200         /*
 201          * we will do the session_close and root dentry release
 202          * in the below call. But we need to clunk fid, because we haven't
 203          * attached the fid to dentry so it won't get clunked
 204          * automatically.
 205          */
 206         p9_fid_put(fid);
 207         deactivate_locked_super(sb);
 208         return ERR_PTR(retval);
 209 }
 210
 211 /**
 212  * v9fs_kill_super - Kill Superblock
 213  * @s: superblock
 214  *
 215  */
 216
 217 static void v9fs_kill_super(struct super_block *s)
 218 {
 219         struct v9fs_session_info *v9ses = s->s_fs_info;
 220
 221         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 222
 223         kill_anon_super(s);
 224
 225         v9fs_session_cancel(v9ses);
 226         v9fs_session_close(v9ses);
 227         kfree(v9ses);
 228         s->s_fs_info = NULL;
 229         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 230 }
 231
 232 static void
 233 v9fs_umount_begin(struct super_block *sb)
 234 {
 235         struct v9fs_session_info *v9ses;
 236
 237         v9ses = sb->s_fs_info;
 238         v9fs_session_begin_cancel(v9ses);
 239 }
 240
 241 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 242 {
 243         struct v9fs_session_info *v9ses;
 244         struct p9_fid *fid;
 245         struct p9_rstatfs rs;
 246         int res;
 247
 248         fid = v9fs_fid_lookup(dentry);
 249         if (IS_ERR(fid)) {
 250                 res = PTR_ERR(fid);
 251                 goto done;
 252         }
 253
 254         v9ses = v9fs_dentry2v9ses(dentry);
 255         if (v9fs_proto_dotl(v9ses)) {
 256                 res = p9_client_statfs(fid, &rs);
 257                 if (res == 0) {
 258                         buf->f_type = rs.type;
 259                         buf->f_bsize = rs.bsize;
 260                         buf->f_blocks = rs.blocks;
 261                         buf->f_bfree = rs.bfree;
 262                         buf->f_bavail = rs.bavail;
 263                         buf->f_files = rs.files;
 264                         buf->f_ffree = rs.ffree;
 265                         buf->f_fsid = u64_to_fsid(rs.fsid);
 266                         buf->f_namelen = rs.namelen;
 267                 }
 268                 if (res != -ENOSYS)
 269                         goto done;
 270         }
 271         res = simple_statfs(dentry, buf);
 272 done:
 273         p9_fid_put(fid);
 274         return res;
 275 }
 276
 277 static int v9fs_drop_inode(struct inode *inode)
 278 {
 279         struct v9fs_session_info *v9ses;
 280
 281         v9ses = v9fs_inode2v9ses(inode);
 282         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 283                 return generic_drop_inode(inode);
 284         /*
 285          * in case of non cached mode always drop the
 286          * inode because we want the inode attribute
 287          * to always match that on the server.
 288          */
 289         return 1;
 290 }
 291
 292 static int v9fs_write_inode(struct inode *inode,
 293                             struct writeback_control *wbc)
 294 {
 295         int ret;
 296         struct p9_wstat wstat;
 297         struct v9fs_inode *v9inode;
 298         /*
 299          * send an fsync request to server irrespective of
 300          * wbc->sync_mode.
 301          */
 302         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 303         v9inode = V9FS_I(inode);
 304         if (!v9inode->writeback_fid)
 305                 return 0;
 306         v9fs_blank_wstat(&wstat);
 307
 308         ret = p9_client_wstat(v9inode->writeback_fid, &wstat);
 309         if (ret < 0) {
 310                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 311                 return ret;
 312         }
 313         fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
 314         return 0;
 315 }
 316
 317 static int v9fs_write_inode_dotl(struct inode *inode,
 318                                  struct writeback_control *wbc)
 319 {
 320         int ret;
 321         struct v9fs_inode *v9inode;
 322         /*
 323          * send an fsync request to server irrespective of
 324          * wbc->sync_mode.
 325          */
 326         v9inode = V9FS_I(inode);
 327         p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
 328                  __func__, inode, v9inode->writeback_fid);
 329         if (!v9inode->writeback_fid)
 330                 return 0;
 331
 332         ret = p9_client_fsync(v9inode->writeback_fid, 0);
 333         if (ret < 0) {
 334                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 335                 return ret;
 336         }
 337         fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
 338         return 0;
 339 }
 340
 341 static const struct super_operations v9fs_super_ops = {
 342         .alloc_inode = v9fs_alloc_inode,
 343         .free_inode = v9fs_free_inode,
 344         .statfs = simple_statfs,
 345         .evict_inode = v9fs_evict_inode,
 346         .show_options = v9fs_show_options,
 347         .umount_begin = v9fs_umount_begin,
 348         .write_inode = v9fs_write_inode,
 349 };
 350
 351 static const struct super_operations v9fs_super_ops_dotl = {
 352         .alloc_inode = v9fs_alloc_inode,
 353         .free_inode = v9fs_free_inode,
 354         .statfs = v9fs_statfs,
 355         .drop_inode = v9fs_drop_inode,
 356         .evict_inode = v9fs_evict_inode,
 357         .show_options = v9fs_show_options,
 358         .umount_begin = v9fs_umount_begin,
 359         .write_inode = v9fs_write_inode_dotl,
 360 };
 361
 362 struct file_system_type v9fs_fs_type = {
 363         .name = "9p",
 364         .mount = v9fs_mount,
 365         .kill_sb = v9fs_kill_super,
 366         .owner = THIS_MODULE,
 367         .fs_flags = FS_RENAME_DOES_D_MOVE,
 368 };
 369 MODULE_ALIAS_FS("9p");