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         struct p9_fid *fid;
 114         int retval = 0;
 115
 116         p9_debug(P9_DEBUG_VFS, "\n");
 117
 118         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 119         if (!v9ses)
 120                 return ERR_PTR(-ENOMEM);
 121
 122         fid = v9fs_session_init(v9ses, dev_name, data);
 123         if (IS_ERR(fid)) {
 124                 retval = PTR_ERR(fid);
 125                 goto free_session;
 126         }
 127
 128         sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
 129         if (IS_ERR(sb)) {
 130                 retval = PTR_ERR(sb);
 131                 goto clunk_fid;
 132         }
 133         retval = v9fs_fill_super(sb, v9ses, flags);
 134         if (retval)
 135                 goto release_sb;
 136
 137         if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 138                 sb->s_d_op = &v9fs_cached_dentry_operations;
 139         else
 140                 sb->s_d_op = &v9fs_dentry_operations;
 141
 142         inode = v9fs_get_new_inode_from_fid(v9ses, fid, sb);
 143         if (IS_ERR(inode)) {
 144                 retval = PTR_ERR(inode);
 145                 goto release_sb;
 146         }
 147
 148         root = d_make_root(inode);
 149         if (!root) {
 150                 retval = -ENOMEM;
 151                 goto release_sb;
 152         }
 153         sb->s_root = root;
 154         retval = v9fs_get_acl(inode, fid);
 155         if (retval)
 156                 goto release_sb;
 157         v9fs_fid_add(root, &fid);
 158
 159         p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
 160         return dget(sb->s_root);
 161
 162 clunk_fid:
 163         p9_fid_put(fid);
 164         v9fs_session_close(v9ses);
 165 free_session:
 166         kfree(v9ses);
 167         return ERR_PTR(retval);
 168
 169 release_sb:
 170         /*
 171          * we will do the session_close and root dentry release
 172          * in the below call. But we need to clunk fid, because we haven't
 173          * attached the fid to dentry so it won't get clunked
 174          * automatically.
 175          */
 176         p9_fid_put(fid);
 177         deactivate_locked_super(sb);
 178         return ERR_PTR(retval);
 179 }
 180
 181 /**
 182  * v9fs_kill_super - Kill Superblock
 183  * @s: superblock
 184  *
 185  */
 186
 187 static void v9fs_kill_super(struct super_block *s)
 188 {
 189         struct v9fs_session_info *v9ses = s->s_fs_info;
 190
 191         p9_debug(P9_DEBUG_VFS, " %p\n", s);
 192
 193         kill_anon_super(s);
 194
 195         v9fs_session_cancel(v9ses);
 196         v9fs_session_close(v9ses);
 197         kfree(v9ses);
 198         s->s_fs_info = NULL;
 199         p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
 200 }
 201
 202 static void
 203 v9fs_umount_begin(struct super_block *sb)
 204 {
 205         struct v9fs_session_info *v9ses;
 206
 207         v9ses = sb->s_fs_info;
 208         v9fs_session_begin_cancel(v9ses);
 209 }
 210
 211 static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 212 {
 213         struct v9fs_session_info *v9ses;
 214         struct p9_fid *fid;
 215         struct p9_rstatfs rs;
 216         int res;
 217
 218         fid = v9fs_fid_lookup(dentry);
 219         if (IS_ERR(fid)) {
 220                 res = PTR_ERR(fid);
 221                 goto done;
 222         }
 223
 224         v9ses = v9fs_dentry2v9ses(dentry);
 225         if (v9fs_proto_dotl(v9ses)) {
 226                 res = p9_client_statfs(fid, &rs);
 227                 if (res == 0) {
 228                         buf->f_type = rs.type;
 229                         buf->f_bsize = rs.bsize;
 230                         buf->f_blocks = rs.blocks;
 231                         buf->f_bfree = rs.bfree;
 232                         buf->f_bavail = rs.bavail;
 233                         buf->f_files = rs.files;
 234                         buf->f_ffree = rs.ffree;
 235                         buf->f_fsid = u64_to_fsid(rs.fsid);
 236                         buf->f_namelen = rs.namelen;
 237                 }
 238                 if (res != -ENOSYS)
 239                         goto done;
 240         }
 241         res = simple_statfs(dentry, buf);
 242 done:
 243         p9_fid_put(fid);
 244         return res;
 245 }
 246
 247 static int v9fs_drop_inode(struct inode *inode)
 248 {
 249         struct v9fs_session_info *v9ses;
 250
 251         v9ses = v9fs_inode2v9ses(inode);
 252         if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 253                 return generic_drop_inode(inode);
 254         /*
 255          * in case of non cached mode always drop the
 256          * inode because we want the inode attribute
 257          * to always match that on the server.
 258          */
 259         return 1;
 260 }
 261
 262 static int v9fs_write_inode(struct inode *inode,
 263                             struct writeback_control *wbc)
 264 {
 265         /*
 266          * send an fsync request to server irrespective of
 267          * wbc->sync_mode.
 268          */
 269         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 270         return netfs_unpin_writeback(inode, wbc);
 271 }
 272
 273 static int v9fs_write_inode_dotl(struct inode *inode,
 274                                  struct writeback_control *wbc)
 275 {
 276
 277         p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 278
 279         return netfs_unpin_writeback(inode, wbc);
 280 }
 281
 282 static const struct super_operations v9fs_super_ops = {
 283         .alloc_inode = v9fs_alloc_inode,
 284         .free_inode = v9fs_free_inode,
 285         .statfs = simple_statfs,
 286         .drop_inode = v9fs_drop_inode,
 287         .evict_inode = v9fs_evict_inode,
 288         .show_options = v9fs_show_options,
 289         .umount_begin = v9fs_umount_begin,
 290         .write_inode = v9fs_write_inode,
 291 };
 292
 293 static const struct super_operations v9fs_super_ops_dotl = {
 294         .alloc_inode = v9fs_alloc_inode,
 295         .free_inode = v9fs_free_inode,
 296         .statfs = v9fs_statfs,
 297         .drop_inode = v9fs_drop_inode,
 298         .evict_inode = v9fs_evict_inode,
 299         .show_options = v9fs_show_options,
 300         .umount_begin = v9fs_umount_begin,
 301         .write_inode = v9fs_write_inode_dotl,
 302 };
 303
 304 struct file_system_type v9fs_fs_type = {
 305         .name = "9p",
 306         .mount = v9fs_mount,
 307         .kill_sb = v9fs_kill_super,
 308         .owner = THIS_MODULE,
 309         .fs_flags = FS_RENAME_DOES_D_MOVE,
 310 };
 311 MODULE_ALIAS_FS("9p");