sys/vfs/dirfs/dirfs_vfsops.c

   1 /*
   2  * Copyright (c) 2013 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Antonio Huete Jimenez <tuxillo@quantumachine.net>
   6  * by Matthew Dillon <dillon@dragonflybsd.org>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  */
  36
  37 #include <sys/vfsops.h>
  38 #include <sys/mount.h>
  39 #include <sys/types.h>
  40 #include <sys/systm.h>
  41 #include <sys/param.h>
  42 #include <sys/module.h>
  43 #include <sys/kernel.h>
  44 #include <sys/malloc.h>
  45 #include <sys/sysctl.h>
  46 #include <sys/queue.h>
  47 #include <sys/spinlock2.h>
  48 #include <sys/ktr.h>
  49
  50 #include <string.h>
  51
  52 #include "dirfs.h"
  53
  54 MALLOC_DEFINE(M_DIRFS, "dirfs", "dirfs mount allocation");
  55 MALLOC_DEFINE(M_DIRFS_NODE, "dirfs nodes", "dirfs nodes memory allocation");
  56 MALLOC_DEFINE(M_DIRFS_MISC, "dirfs misc", "dirfs miscellaneous allocation");
  57
  58 /*
  59  * Kernel tracing facilities
  60  */
  61 KTR_INFO_MASTER(dirfs);
  62
  63 KTR_INFO(KTR_DIRFS, dirfs, root, 20,
  64     "DIRFS(root dnp=%p vnode=%p hostdir=%s fd=%d error=%d)",
  65     dirfs_node_t dnp, struct vnode *vp, char *hostdir, int fd, int error);
  66
  67 KTR_INFO(KTR_DIRFS, dirfs, mount, 21,
  68     "DIRFS(mount path=%s dmp=%p mp=%p error=%d)",
  69     char *path, dirfs_mount_t dmp, struct mount *mp, int error);
  70
  71 KTR_INFO(KTR_DIRFS, dirfs, unmount, 22,
  72     "DIRFS(unmount dmp=%p mp=%p error=%d)",
  73     dirfs_mount_t dmp, struct mount *mp, int error);
  74
  75 /* System wide sysctl stuff */
  76 int debuglvl = 0;
  77 int dirfs_fd_limit = 100;
  78 int dirfs_fd_used = 0;
  79 long passive_fd_list_miss = 0;
  80 long passive_fd_list_hits = 0;
  81
  82 SYSCTL_NODE(_vfs, OID_AUTO, dirfs, CTLFLAG_RW, 0,
  83     "dirfs filesystem for vkernels");
  84 SYSCTL_INT(_vfs_dirfs, OID_AUTO, debug, CTLFLAG_RW,
  85     &debuglvl, 0, "dirfs debug level");
  86 SYSCTL_INT(_vfs_dirfs, OID_AUTO, fd_limit, CTLFLAG_RW,
  87     &dirfs_fd_limit, 0, "Maximum number of passive nodes to cache");
  88 SYSCTL_INT(_vfs_dirfs, OID_AUTO, fd_used, CTLFLAG_RD,
  89     &dirfs_fd_used, 0, "Current number of passive nodes cached");
  90 SYSCTL_LONG(_vfs_dirfs, OID_AUTO, passive_fd_list_miss, CTLFLAG_RD,
  91     &passive_fd_list_miss, 0, "Passive fd list cache misses");
  92 SYSCTL_LONG(_vfs_dirfs, OID_AUTO, passive_fd_list_hits, CTLFLAG_RD,
  93     &passive_fd_list_hits, 0, "Passive fd list cache misses");
  94
  95 static int dirfs_statfs(struct mount *, struct statfs *, struct ucred *);
  96
  97 static int
  98 dirfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
  99 {
 100         dirfs_mount_t dmp;
 101         struct stat st;
 102         size_t done, nlen;
 103         int error;
 104
 105         dbg(1, "called\n");
 106
 107         if (mp->mnt_flag & MNT_UPDATE) {
 108                 dmp = VFS_TO_DIRFS(mp);
 109                 if (dmp->dm_rdonly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
 110                         /* XXX We should make sure all writes are synced */
 111                         dmp->dm_rdonly = 1;
 112                         debug(2, "dirfs read-write -> read-only\n");
 113                 }
 114
 115                 if (dmp->dm_rdonly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
 116                         debug(2, "dirfs read-only -> read-write\n");
 117                         dmp->dm_rdonly = 0;
 118                 }
 119                 return 0;
 120         }
 121
 122         dmp = kmalloc(sizeof(*dmp), M_DIRFS, M_WAITOK | M_ZERO);
 123         mp->mnt_data = (qaddr_t)dmp;
 124         dmp->dm_mount = mp;
 125
 126         error = copyinstr(data, &dmp->dm_path, MAXPATHLEN, &done);
 127         if (error) {
 128                 /* Attempt to copy from kernel address */
 129                 error = copystr(data, &dmp->dm_path, MAXPATHLEN, &done);
 130                 if (error) {
 131                         kfree(dmp, M_DIRFS);
 132                         goto failure;
 133                 }
 134         }
 135
 136         /* Strip / character at the end to avoid problems */
 137         nlen = strnlen(dmp->dm_path, MAXPATHLEN);
 138         if (dmp->dm_path[nlen-1] == '/')
 139                 dmp->dm_path[nlen-1] = 0;
 140
 141         /* Make sure host directory exists and it is indeed a directory. */
 142         if ((stat(dmp->dm_path, &st)) == 0) {
 143                 if (!S_ISDIR(st.st_mode)) {
 144                         kfree(dmp, M_DIRFS);
 145                         error = EINVAL;
 146                         goto failure;
 147                 }
 148         } else {
 149                 error = errno;
 150                 goto failure;
 151         }
 152
 153         lockinit(&dmp->dm_lock, "dfsmnt", 0, LK_CANRECURSE);
 154
 155         vfs_add_vnodeops(mp, &dirfs_vnode_vops, &mp->mnt_vn_norm_ops);
 156         vfs_getnewfsid(mp);
 157
 158         /* Who is running the vkernel */
 159         dmp->dm_uid = getuid();
 160         dmp->dm_gid = getgid();
 161
 162         TAILQ_INIT(&dmp->dm_fdlist);
 163         RB_INIT(&dmp->dm_inotree);
 164
 165         kmalloc_raise_limit(M_DIRFS_NODE, 0);
 166
 167         dirfs_statfs(mp, &mp->mnt_stat, cred);
 168
 169 failure:
 170         KTR_LOG(dirfs_mount, (dmp->dm_path) ? dmp->dm_path : "NULL",
 171             dmp, mp, error);
 172
 173         return error;
 174 }
 175
 176 static int
 177 dirfs_unmount(struct mount *mp, int mntflags)
 178 {
 179         dirfs_mount_t dmp;
 180         dirfs_node_t dnp;
 181         int cnt;
 182         int error;
 183
 184         dbg(1, "called\n");
 185         cnt = 0;
 186         dmp = VFS_TO_DIRFS(mp);
 187
 188         error = vflush(mp, 0, 0);
 189         if (error)
 190                 goto failure;
 191
 192         /*
 193          * Clean up dm_fdlist.  There should be no vnodes left so the
 194          * only ref should be from the fdlist.
 195          */
 196         while ((dnp = TAILQ_FIRST(&dmp->dm_fdlist)) != NULL) {
 197                 dirfs_node_setpassive(dmp, dnp, 0);
 198         }
 199
 200         /*
 201          * Cleanup root node. In the case the filesystem is mounted
 202          * but no operation is done on it, there will be no call to
 203          * VFS_ROOT() so better check dnp is not NULL before attempting
 204          * to release it.
 205          */
 206         dnp = dmp->dm_root;
 207         if (dnp != NULL) {
 208                 dirfs_close_helper(dnp);
 209                 debug_node2(dnp);
 210                 dirfs_node_drop(dmp, dnp); /* last ref should free structure */
 211         }
 212         kfree(dmp, M_DIRFS);
 213         mp->mnt_data = (qaddr_t) 0;
 214
 215 failure:
 216         KTR_LOG(dirfs_unmount, dmp, mp, error);
 217
 218         return error;
 219 }
 220
 221 static int
 222 dirfs_root(struct mount *mp, struct vnode **vpp)
 223 {
 224         dirfs_mount_t dmp;
 225         dirfs_node_t dnp;
 226         int fd;
 227         int error;
 228
 229         dbg(1, "called\n");
 230
 231         dmp = VFS_TO_DIRFS(mp);
 232         KKASSERT(dmp != NULL);
 233
 234         if (dmp->dm_root == NULL) {
 235                 /*
 236                  * dm_root holds the root dirfs node. Allocate a new one since
 237                  * there is none. Also attempt to lstat(2) it, in order to set
 238                  * data for VOP_ACCESS()
 239                  */
 240                 dnp = dirfs_node_alloc(mp);
 241                 error = dirfs_node_stat(DIRFS_NOFD, dmp->dm_path, dnp);
 242                 if (error != 0) {
 243                         dirfs_node_free(dmp, dnp);
 244                         return error;
 245                 }
 246                 dirfs_node_ref(dnp);    /* leave inact for life of mount */
 247
 248                 /* Root inode's parent is NULL, used for verification */
 249                 dnp->dn_parent = NULL;
 250                 dmp->dm_root = dnp;
 251                 dirfs_node_setflags(dnp, DIRFS_ROOT);
 252
 253                 /*
 254                  * Maintain an open descriptor on the root dnp.  The
 255                  * normal open/close/cache does not apply for the root
 256                  * so the descriptor is ALWAYS available.
 257                  */
 258                 fd = open(dmp->dm_path, O_DIRECTORY);
 259                 if (fd == -1) {
 260                         dbg(9, "failed to open ROOT node\n");
 261                         dirfs_free_vp(dmp, dnp);
 262                         dirfs_node_free(dmp, dnp);
 263                         return errno;
 264                 }
 265                 dnp->dn_fd = fd;
 266                 dnp->dn_type = VDIR;
 267         } else {
 268                 dnp = dmp->dm_root;
 269         }
 270
 271         /*
 272          * Acquire the root vnode (dn_type already set above).  This
 273          * call will handle any races and return a locked vnode.
 274          */
 275         dirfs_alloc_vp(mp, vpp, LK_CANRECURSE, dnp);
 276         KTR_LOG(dirfs_root, dnp, *vpp, dmp->dm_path, dnp->dn_fd, error);
 277
 278         return 0;
 279 }
 280
 281 static int
 282 dirfs_fhtovp(struct mount *mp, struct vnode *rootvp, struct fid *fhp, struct vnode **vpp)
 283 {
 284         dbg(1, "called\n");
 285
 286         return EOPNOTSUPP;
 287 }
 288
 289 static int
 290 dirfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
 291 {
 292         dirfs_mount_t dmp = VFS_TO_DIRFS(mp);
 293         struct statfs st;
 294
 295         dbg(1, "called\n");
 296
 297         if((statfs(dmp->dm_path, &st)) == -1)
 298                 return errno;
 299
 300         ksnprintf(st.f_mntfromname, MNAMELEN - 1, "dirfs@%s", dmp->dm_path);
 301         bcopy(&st, sbp, sizeof(st));
 302         strlcpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
 303         dbg(5, "iosize = %zd\n", sbp->f_iosize);
 304
 305         return 0;
 306 }
 307
 308 static int
 309 dirfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
 310 {
 311         dirfs_mount_t dmp = VFS_TO_DIRFS(mp);
 312         struct statvfs st;
 313
 314         dbg(1, "called\n");
 315
 316         if ((statvfs(dmp->dm_path, &st)) == -1)
 317                 return errno;
 318
 319         bcopy(&st, sbp, sizeof(st));
 320
 321         return 0;
 322 }
 323
 324 static int
 325 dirfs_vptofh(struct vnode *vp, struct fid *fhp)
 326 {
 327         dirfs_node_t dnp;
 328
 329         dnp = VP_TO_NODE(vp);
 330         debug_node2(dnp);
 331         dbg(1, "called\n");
 332
 333         return EOPNOTSUPP;
 334 }
 335
 336 static int
 337 dirfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp,
 338                struct ucred **credanonp)
 339 {
 340         dbg(1, "called\n");
 341
 342         return EOPNOTSUPP;
 343 }
 344
 345 static struct vfsops dirfs_vfsops = {
 346         .vfs_mount =                    dirfs_mount,
 347         .vfs_unmount =                  dirfs_unmount,
 348         .vfs_root =                     dirfs_root,
 349         .vfs_vget =                     vfs_stdvget,
 350         .vfs_statfs =                   dirfs_statfs,
 351         .vfs_statvfs =                  dirfs_statvfs,
 352         .vfs_fhtovp =                   dirfs_fhtovp,
 353         .vfs_vptofh =                   dirfs_vptofh,
 354         .vfs_checkexp =                 dirfs_checkexp
 355 };
 356
 357 VFS_SET(dirfs_vfsops, dirfs, 0);
 358 MODULE_VERSION(dirfs, 1);