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/pagemap.h>
  16 #include <linux/mount.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <linux/statfs.h>
  20 #include <linux/magic.h>
  21 #include <linux/fscache.h>
  22 #include <net/9p/9p.h>
  23 #include <net/9p/client.h>
  24
  25 #include "v9fs.h"
  26 #include "v9fs_vfs.h"
  27 #include "fid.h"
  28 #include "xattr.h"
  29 #include "acl.h"
  30
  31 static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
  32
  33 /**
  34  * v9fs_set_super - set the superblock
  35  * @s: super block
  36  * @data: file system specific data
  37  *
  38  */
  39
  40 static int v9fs_set_super(struct super_block *s, void *data)
  41 {
  42         s->s_fs_info = data;
  43         return set_anon_super(s, data);
  44 }
  45
  46 /**
  47  * v9fs_fill_super - populate superblock with info
  48  * @sb: superblock
  49  * @v9ses: session information
  50  * @flags: flags propagated from v9fs_mount()
  51  *
  52  */
  53
  54 static int
  55 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  56                 int flags)
  57 {
  58         int ret;
  59
  60         sb->s_maxbytes = MAX_LFS_FILESIZE;
  61         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  62         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  63         sb->s_magic = V9FS_MAGIC;
  64         if (v9fs_proto_dotl(v9ses)) {
  65                 sb->s_op = &v9fs_super_ops_dotl;
  66                 if (!(v9ses->flags & V9FS_NO_XATTR))
  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;
  88
  89 #ifdef CONFIG_9P_FS_POSIX_ACL
  90         if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
  91                 sb->s_flags |= SB_POSIXACL;
  92 #endif
  93
  94         return 0;
  95 }
  96
  97 /**
  98  * v9fs_mount - mount a superblock
  99  * @fs_type: file system type
 100  * @flags: mount flags
 101  * @dev_name: device name that was mounted
 102  * @data: mount options
 103  *
 104  */
 105
 106 static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 107                        const char *dev_name, void *data)
 108 {
 109         struct super_block *sb = NULL;
 110         struct inode *inode = NULL;
 111         struct dentry *root = NULL;
 112         struct v9fs_session_info *v9ses = NULL;
 113         umode_t mode = 0777 | S_ISVTX;
 114         struct p9_fid *fid;
 115         int retval = 0;
 116
 117         p9_debug(P9_DEBUG_VFS, "\n");
 118
 119         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 120         if (!v9ses)
 121                 return ERR_PTR(-ENOMEM);
 122
 123         fid = v9fs_session_init(v9ses, dev_name, data);
 124         if (IS_ERR(fid)) {
 125                 retval = PTR_ERR(fid);
 126                 goto free_session;
 127         }
 128
 129         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 130         if (IS_ERR(sb)) {
 131                 retval = PTR_ERR(sb);
 132                 goto clunk_fid;
 133         }
 134         retval = v9fs_fill_super(sb, v9ses, flags);
 135         if (retval)
 136                 goto release_sb;
 137
 138         if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 139                 sb->s_d_op = &v9fs_cached_dentry_operations;
 140         else
 141                 sb->s_d_op = &v9fs_dentry_operations;
 142
 143         inode = v9fs_get_inode(sb, S_IFDIR | mode, 0);
 144         if (IS_ERR(inode)) {
 145                 retval = PTR_ERR(inode);
 146                 goto release_sb;
 147         }
 148
 149         root = d_make_root(inode);
 150         if (!root) {
 151                 retval = -ENOMEM;
 152                 goto release_sb;
 153         }
 154         sb->s_root = root;
 155         if (v9fs_proto_dotl(v9ses)) {
 156                 struct p9_stat_dotl *st = NULL;
 157
 158                 st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
 159                 if (IS_ERR(st)) {
 160                         retval = PTR_ERR(st);
 161                         goto release_sb;
 162                 }
 163                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 164                 v9fs_stat2inode_dotl(st, d_inode(root), 0);
 165                 kfree(st);
 166         } else {
 167                 struct p9_wstat *st = NULL;
 168
 169                 st = p9_client_stat(fid);
 170                 if (IS_ERR(st)) {
 171                         retval = PTR_ERR(st);
 172                         goto release_sb;
 173                 }
 174
 175                 d_inode(root)->i_ino = v9fs_qid2ino(&st->qid);
 176                 v9fs_stat2inode(st, d_inode(root), sb, 0);
 177
 178                 p9stat_free(st);
 179                 kfree(st);
 180         }
 181         retval = v9fs_get_acl(inode, fid);
 182         if (retval)
 183                 goto release_sb;
 184         v9fs_fid_add(root, &fid);
 185
 186         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 187         return dget(sb->s_root);
 188
 189 clunk_fid:
 190         p9_fid_put(fid);
 191         v9fs_session_close(v9ses);
 192 free_session:
 193         kfree(v9ses);
 194         return ERR_PTR(retval);
 195
 196 release_sb:
 197         /*
 198          * we will do the session_close and root dentry release
 199          * in the below call. But we need to clunk fid, because we haven't
 200          * attached the fid to dentry so it won't get clunked
 201          * automatically.
 202          */
 203         p9_fid_put(fid);
 204         deactivate_locked_super(sb);
 205         return ERR_PTR(retval);
 206 }
 207
 208 /**
 209  * v9fs_kill_super - Kill Superblock
 210  * @s: superblock
 211  *
 212  */
 213
 214 static void v9fs_kill_super(struct super_block *s)
 215 {
 216         struct v9fs_session_info *v9ses = s->s_fs_info;
 217
 218         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 219
 220         kill_anon_super(s);
 221
 222         v9fs_session_cancel(v9ses);
 223         v9fs_session_close(v9ses);
 224         kfree(v9ses);
 225         s->s_fs_info = NULL;
 226         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 227 }
 228
 229 static void
 230 v9fs_umount_begin(struct super_block *sb)
 231 {
 232         struct v9fs_session_info *v9ses;
 233
 234         v9ses = sb->s_fs_info;
 235         v9fs_session_begin_cancel(v9ses);
 236 }
 237
 238 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 239 {
 240         struct v9fs_session_info *v9ses;
 241         struct p9_fid *fid;
 242         struct p9_rstatfs rs;
 243         int res;
 244
 245         fid = v9fs_fid_lookup(dentry);
 246         if (IS_ERR(fid)) {
 247                 res = PTR_ERR(fid);
 248                 goto done;
 249         }
 250
 251         v9ses = v9fs_dentry2v9ses(dentry);
 252         if (v9fs_proto_dotl(v9ses)) {
 253                 res = p9_client_statfs(fid, &rs);
 254                 if (res == 0) {
 255                         buf->f_type = rs.type;
 256                         buf->f_bsize = rs.bsize;
 257                         buf->f_blocks = rs.blocks;
 258                         buf->f_bfree = rs.bfree;
 259                         buf->f_bavail = rs.bavail;
 260                         buf->f_files = rs.files;
 261                         buf->f_ffree = rs.ffree;
 262                         buf->f_fsid = u64_to_fsid(rs.fsid);
 263                         buf->f_namelen = rs.namelen;
 264                 }
 265                 if (res != -ENOSYS)
 266                         goto done;
 267         }
 268         res = simple_statfs(dentry, buf);
 269 done:
 270         p9_fid_put(fid);
 271         return res;
 272 }
 273
 274 static int v9fs_drop_inode(struct inode *inode)
 275 {
 276         struct v9fs_session_info *v9ses;
 277
 278         v9ses = v9fs_inode2v9ses(inode);
 279         if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 280                 return generic_drop_inode(inode);
 281         /*
 282          * in case of non cached mode always drop the
 283          * inode because we want the inode attribute
 284          * to always match that on the server.
 285          */
 286         return 1;
 287 }
 288
 289 static int v9fs_write_inode(struct inode *inode,
 290                             struct writeback_control *wbc)
 291 {
 292         struct v9fs_inode *v9inode;
 293
 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
 300         v9inode = V9FS_I(inode);
 301         fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
 302
 303         return 0;
 304 }
 305
 306 static int v9fs_write_inode_dotl(struct inode *inode,
 307                                  struct writeback_control *wbc)
 308 {
 309         struct v9fs_inode *v9inode;
 310
 311         v9inode = V9FS_I(inode);
 312         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 313
 314         fscache_unpin_writeback(wbc, v9fs_inode_cookie(v9inode));
 315
 316         return 0;
 317 }
 318
 319 static const struct super_operations v9fs_super_ops = {
 320         .alloc_inode = v9fs_alloc_inode,
 321         .free_inode = v9fs_free_inode,
 322         .statfs = simple_statfs,
 323         .evict_inode = v9fs_evict_inode,
 324         .show_options = v9fs_show_options,
 325         .umount_begin = v9fs_umount_begin,
 326         .write_inode = v9fs_write_inode,
 327 };
 328
 329 static const struct super_operations v9fs_super_ops_dotl = {
 330         .alloc_inode = v9fs_alloc_inode,
 331         .free_inode = v9fs_free_inode,
 332         .statfs = v9fs_statfs,
 333         .drop_inode = v9fs_drop_inode,
 334         .evict_inode = v9fs_evict_inode,
 335         .show_options = v9fs_show_options,
 336         .umount_begin = v9fs_umount_begin,
 337         .write_inode = v9fs_write_inode_dotl,
 338 };
 339
 340 struct file_system_type v9fs_fs_type = {
 341         .name = "9p",
 342         .mount = v9fs_mount,
 343         .kill_sb = v9fs_kill_super,
 344         .owner = THIS_MODULE,
 345         .fs_flags = FS_RENAME_DOES_D_MOVE,
 346 };
 347 MODULE_ALIAS_FS("9p");