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  1. /*
  2.  * Copyright (c) 2008 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup fs
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file    tmpfs_ops.c
  35.  * @brief   Implementation of VFS operations for the TMPFS file system
  36.  *      server.
  37.  */
  38.  
  39. #include "tmpfs.h"
  40. #include "../../vfs/vfs.h"
  41. #include <ipc/ipc.h>
  42. #include <async.h>
  43. #include <errno.h>
  44. #include <atomic.h>
  45. #include <stdlib.h>
  46. #include <string.h>
  47. #include <stdio.h>
  48. #include <assert.h>
  49. #include <sys/types.h>
  50. #include <libadt/hash_table.h>
  51. #include <as.h>
  52. #include <libfs.h>
  53.  
  54. #define min(a, b)       ((a) < (b) ? (a) : (b))
  55. #define max(a, b)       ((a) > (b) ? (a) : (b))
  56.  
  57. #define DENTRIES_BUCKETS    256
  58.  
  59. #define NAMES_BUCKETS       4
  60.  
  61. /*
  62.  * For now, we don't distinguish between different dev_handles/instances. All
  63.  * requests resolve to the only instance, rooted in the following variable.
  64.  */
  65. static tmpfs_dentry_t *root;
  66.  
  67. #define TMPFS_DEV       0   /**< Dummy device handle for TMPFS */
  68.  
  69. /*
  70.  * Implementation of the libfs interface.
  71.  */
  72.  
  73. /* Forward declarations of static functions. */
  74. static void *tmpfs_match(void *, const char *);
  75. static void *tmpfs_node_get(dev_handle_t, fs_index_t);
  76. static void tmpfs_node_put(void *);
  77. static void *tmpfs_create_node(dev_handle_t, int);
  78. static int tmpfs_link_node(void *, void *, const char *);
  79. static int tmpfs_unlink_node(void *, void *);
  80. static int tmpfs_destroy_node(void *);
  81.  
  82. /* Implementation of helper functions. */
  83. static fs_index_t tmpfs_index_get(void *nodep)
  84. {
  85.     return ((tmpfs_dentry_t *) nodep)->index;
  86. }
  87.  
  88. static size_t tmpfs_size_get(void *nodep)
  89. {
  90.     return ((tmpfs_dentry_t *) nodep)->size;
  91. }
  92.  
  93. static unsigned tmpfs_lnkcnt_get(void *nodep)
  94. {
  95.     return ((tmpfs_dentry_t *) nodep)->lnkcnt;
  96. }
  97.  
  98. static bool tmpfs_has_children(void *nodep)
  99. {
  100.     return ((tmpfs_dentry_t *) nodep)->child != NULL;
  101. }
  102.  
  103. static void *tmpfs_root_get(dev_handle_t dev_handle)
  104. {
  105.     return root;
  106. }
  107.  
  108. static char tmpfs_plb_get_char(unsigned pos)
  109. {
  110.     return tmpfs_reg.plb_ro[pos % PLB_SIZE];
  111. }
  112.  
  113. static bool tmpfs_is_directory(void *nodep)
  114. {
  115.     return ((tmpfs_dentry_t *) nodep)->type == TMPFS_DIRECTORY;
  116. }
  117.  
  118. static bool tmpfs_is_file(void *nodep)
  119. {
  120.     return ((tmpfs_dentry_t *) nodep)->type == TMPFS_FILE;
  121. }
  122.  
  123. /** libfs operations */
  124. libfs_ops_t tmpfs_libfs_ops = {
  125.     .match = tmpfs_match,
  126.     .node_get = tmpfs_node_get,
  127.     .node_put = tmpfs_node_put,
  128.     .create = tmpfs_create_node,
  129.     .destroy = tmpfs_destroy_node,
  130.     .link = tmpfs_link_node,
  131.     .unlink = tmpfs_unlink_node,
  132.     .index_get = tmpfs_index_get,
  133.     .size_get = tmpfs_size_get,
  134.     .lnkcnt_get = tmpfs_lnkcnt_get,
  135.     .has_children = tmpfs_has_children,
  136.     .root_get = tmpfs_root_get,
  137.     .plb_get_char = tmpfs_plb_get_char,
  138.     .is_directory = tmpfs_is_directory,
  139.     .is_file = tmpfs_is_file
  140. };
  141.  
  142. /** Hash table of all directory entries. */
  143. hash_table_t dentries;
  144.  
  145. /* Implementation of hash table interface for the dentries hash table. */
  146. static hash_index_t dentries_hash(unsigned long *key)
  147. {
  148.     return *key % DENTRIES_BUCKETS;
  149. }
  150.  
  151. static int dentries_compare(unsigned long *key, hash_count_t keys,
  152.     link_t *item)
  153. {
  154.     tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,
  155.         dh_link);
  156.     return dentry->index == *key;
  157. }
  158.  
  159. static void dentries_remove_callback(link_t *item)
  160. {
  161. }
  162.  
  163. /** TMPFS dentries hash table operations. */
  164. hash_table_operations_t dentries_ops = {
  165.     .hash = dentries_hash,
  166.     .compare = dentries_compare,
  167.     .remove_callback = dentries_remove_callback
  168. };
  169.  
  170. fs_index_t tmpfs_next_index = 1;
  171.  
  172. typedef struct {
  173.     char *name;
  174.     tmpfs_dentry_t *parent;
  175.     link_t link;
  176. } tmpfs_name_t;
  177.  
  178. /* Implementation of hash table interface for the names hash table. */
  179. static hash_index_t names_hash(unsigned long *key)
  180. {
  181.     tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) *key;
  182.     return dentry->index % NAMES_BUCKETS;
  183. }
  184.  
  185. static int names_compare(unsigned long *key, hash_count_t keys, link_t *item)
  186. {
  187.     tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) *key;
  188.     tmpfs_name_t *namep = hash_table_get_instance(item, tmpfs_name_t,
  189.         link);
  190.     return dentry == namep->parent;
  191. }
  192.  
  193. static void names_remove_callback(link_t *item)
  194. {
  195.     tmpfs_name_t *namep = hash_table_get_instance(item, tmpfs_name_t,
  196.         link);
  197.     free(namep->name);
  198.     free(namep);
  199. }
  200.  
  201. /** TMPFS node names hash table operations. */
  202. static hash_table_operations_t names_ops = {
  203.     .hash = names_hash,
  204.     .compare = names_compare,
  205.     .remove_callback = names_remove_callback
  206. };
  207.  
  208. static void tmpfs_name_initialize(tmpfs_name_t *namep)
  209. {
  210.     namep->name = NULL;
  211.     namep->parent = NULL;
  212.     link_initialize(&namep->link);
  213. }
  214.  
  215. static bool tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)
  216. {
  217.     dentry->index = 0;
  218.     dentry->sibling = NULL;
  219.     dentry->child = NULL;
  220.     dentry->type = TMPFS_NONE;
  221.     dentry->lnkcnt = 0;
  222.     dentry->size = 0;
  223.     dentry->data = NULL;
  224.     link_initialize(&dentry->dh_link);
  225.     return (bool)hash_table_create(&dentry->names, NAMES_BUCKETS, 1,
  226.         &names_ops);
  227. }
  228.  
  229. static bool tmpfs_init(void)
  230. {
  231.     if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))
  232.         return false;
  233.     root = (tmpfs_dentry_t *) tmpfs_create_node(TMPFS_DEV, L_DIRECTORY);
  234.     if (!root) {
  235.         hash_table_destroy(&dentries);
  236.         return false;
  237.     }
  238.     root->lnkcnt = 0;   /* FS root is not linked */
  239.     return true;
  240. }
  241.  
  242. /** Compare one component of path to a directory entry.
  243.  *
  244.  * @param parentp   Pointer to node from which we descended.
  245.  * @param childp    Pointer to node to compare the path component with.
  246.  * @param component Array of characters holding component name.
  247.  *
  248.  * @return      True on match, false otherwise.
  249.  */
  250. static bool
  251. tmpfs_match_one(tmpfs_dentry_t *parentp, tmpfs_dentry_t *childp,
  252.     const char *component)
  253. {
  254.     unsigned long key = (unsigned long) parentp;
  255.     link_t *hlp = hash_table_find(&childp->names, &key);
  256.     assert(hlp);
  257.     tmpfs_name_t *namep = hash_table_get_instance(hlp, tmpfs_name_t, link);
  258.     return !strcmp(namep->name, component);
  259. }
  260.  
  261. void *tmpfs_match(void *prnt, const char *component)
  262. {
  263.     tmpfs_dentry_t *parentp = (tmpfs_dentry_t *) prnt;
  264.     tmpfs_dentry_t *childp = parentp->child;
  265.  
  266.     while (childp && !tmpfs_match_one(parentp, childp, component))
  267.         childp = childp->sibling;
  268.  
  269.     return (void *) childp;
  270. }
  271.  
  272. void *
  273. tmpfs_node_get(dev_handle_t dev_handle, fs_index_t index)
  274. {
  275.     unsigned long key = index;
  276.     link_t *lnk = hash_table_find(&dentries, &key);
  277.     if (!lnk)
  278.         return NULL;
  279.     return hash_table_get_instance(lnk, tmpfs_dentry_t, dh_link);
  280. }
  281.  
  282. void tmpfs_node_put(void *node)
  283. {
  284.     /* nothing to do */
  285. }
  286.  
  287. void *tmpfs_create_node(dev_handle_t dev_handle, int lflag)
  288. {
  289.     assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));
  290.  
  291.     tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t));
  292.     if (!node)
  293.         return NULL;
  294.  
  295.     if (!tmpfs_dentry_initialize(node)) {
  296.         free(node);
  297.         return NULL;
  298.     }
  299.     node->index = tmpfs_next_index++;
  300.     if (lflag & L_DIRECTORY)
  301.         node->type = TMPFS_DIRECTORY;
  302.     else
  303.         node->type = TMPFS_FILE;
  304.  
  305.     /* Insert the new node into the dentry hash table. */
  306.     unsigned long key = node->index;
  307.     hash_table_insert(&dentries, &key, &node->dh_link);
  308.     return (void *) node;
  309. }
  310.  
  311. int tmpfs_link_node(void *prnt, void *chld, const char *nm)
  312. {
  313.     tmpfs_dentry_t *parentp = (tmpfs_dentry_t *) prnt;
  314.     tmpfs_dentry_t *childp = (tmpfs_dentry_t *) chld;
  315.  
  316.     assert(parentp->type == TMPFS_DIRECTORY);
  317.  
  318.     tmpfs_name_t *namep = malloc(sizeof(tmpfs_name_t));
  319.     if (!namep)
  320.         return ENOMEM;
  321.     tmpfs_name_initialize(namep);
  322.     size_t len = strlen(nm);
  323.     namep->name = malloc(len + 1);
  324.     if (!namep->name) {
  325.         free(namep);
  326.         return ENOMEM;
  327.     }
  328.     strcpy(namep->name, nm);
  329.     namep->parent = parentp;
  330.    
  331.     childp->lnkcnt++;
  332.  
  333.     unsigned long key = (unsigned long) parentp;
  334.     hash_table_insert(&childp->names, &key, &namep->link);
  335.  
  336.     /* Insert the new node into the namespace. */
  337.     if (parentp->child) {
  338.         tmpfs_dentry_t *tmp = parentp->child;
  339.         while (tmp->sibling)
  340.             tmp = tmp->sibling;
  341.         tmp->sibling = childp;
  342.     } else {
  343.         parentp->child = childp;
  344.     }
  345.  
  346.     return EOK;
  347. }
  348.  
  349. int tmpfs_unlink_node(void *prnt, void *chld)
  350. {
  351.     tmpfs_dentry_t *parentp = (tmpfs_dentry_t *)prnt;
  352.     tmpfs_dentry_t *childp = (tmpfs_dentry_t *)chld;
  353.  
  354.     if (!parentp)
  355.         return EBUSY;
  356.  
  357.     if (childp->child)
  358.         return ENOTEMPTY;
  359.  
  360.     if (parentp->child == childp) {
  361.         parentp->child = childp->sibling;
  362.     } else {
  363.         /* TODO: consider doubly linked list for organizing siblings. */
  364.         tmpfs_dentry_t *tmp = parentp->child;
  365.         while (tmp->sibling != childp)
  366.             tmp = tmp->sibling;
  367.         tmp->sibling = childp->sibling;
  368.     }
  369.     childp->sibling = NULL;
  370.  
  371.     unsigned long key = (unsigned long) parentp;
  372.     hash_table_remove(&childp->names, &key, 1);
  373.  
  374.     childp->lnkcnt--;
  375.  
  376.     return EOK;
  377. }
  378.  
  379. int tmpfs_destroy_node(void *nodep)
  380. {
  381.     tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep;
  382.    
  383.     assert(!dentry->lnkcnt);
  384.     assert(!dentry->child);
  385.     assert(!dentry->sibling);
  386.  
  387.     unsigned long key = dentry->index;
  388.     hash_table_remove(&dentries, &key, 1);
  389.  
  390.     hash_table_destroy(&dentry->names);
  391.  
  392.     if (dentry->type == TMPFS_FILE)
  393.         free(dentry->data);
  394.     free(dentry);
  395.     return EOK;
  396. }
  397.  
  398. void tmpfs_mounted(ipc_callid_t rid, ipc_call_t *request)
  399. {
  400.     dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
  401.  
  402.     /* Initialize TMPFS. */
  403.     if (!root && !tmpfs_init()) {
  404.         ipc_answer_0(rid, ENOMEM);
  405.         return;
  406.     }
  407.  
  408.     if (dev_handle >= 0) {
  409.         if (tmpfs_restore(dev_handle))
  410.             ipc_answer_3(rid, EOK, root->index, root->size,
  411.                 root->lnkcnt);
  412.         else
  413.             ipc_answer_0(rid, ELIMIT);
  414.     } else {
  415.         ipc_answer_3(rid, EOK, root->index, root->size, root->lnkcnt);
  416.     }
  417. }
  418.  
  419. void tmpfs_mount(ipc_callid_t rid, ipc_call_t *request)
  420. {
  421.     dev_handle_t mp_dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
  422.     fs_index_t mp_index = (fs_index_t) IPC_GET_ARG2(*request);
  423.     fs_handle_t mr_fs_handle = (fs_handle_t) IPC_GET_ARG3(*request);
  424.     dev_handle_t mr_dev_handle = (dev_handle_t) IPC_GET_ARG4(*request);
  425.    
  426.     ipc_answer_0(rid, ENOTSUP);
  427. }
  428.  
  429. void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
  430. {
  431.     libfs_lookup(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request);
  432. }
  433.  
  434. void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)
  435. {
  436.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  437.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  438.     off_t pos = (off_t)IPC_GET_ARG3(*request);
  439.  
  440.     /*
  441.      * Lookup the respective dentry.
  442.      */
  443.     link_t *hlp;
  444.     unsigned long key = index;
  445.     hlp = hash_table_find(&dentries, &key);
  446.     if (!hlp) {
  447.         ipc_answer_0(rid, ENOENT);
  448.         return;
  449.     }
  450.     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
  451.         dh_link);
  452.  
  453.     /*
  454.      * Receive the read request.
  455.      */
  456.     ipc_callid_t callid;
  457.     size_t len;
  458.     if (!ipc_data_read_receive(&callid, &len)) {
  459.         ipc_answer_0(callid, EINVAL);  
  460.         ipc_answer_0(rid, EINVAL);
  461.         return;
  462.     }
  463.  
  464.     size_t bytes;
  465.     if (dentry->type == TMPFS_FILE) {
  466.         bytes = max(0, min(dentry->size - pos, len));
  467.         (void) ipc_data_read_finalize(callid, dentry->data + pos,
  468.             bytes);
  469.     } else {
  470.         int i;
  471.         tmpfs_dentry_t *cur;
  472.        
  473.         assert(dentry->type == TMPFS_DIRECTORY);
  474.        
  475.         /*
  476.          * Yes, we really use O(n) algorithm here.
  477.          * If it bothers someone, it could be fixed by introducing a
  478.          * hash table.
  479.          */
  480.         for (i = 0, cur = dentry->child; i < pos && cur; i++,
  481.             cur = cur->sibling)
  482.             ;
  483.  
  484.         if (!cur) {
  485.             ipc_answer_0(callid, ENOENT);
  486.             ipc_answer_1(rid, ENOENT, 0);
  487.             return;
  488.         }
  489.  
  490.         unsigned long key = (unsigned long) dentry;
  491.         link_t *hlp = hash_table_find(&cur->names, &key);
  492.         assert(hlp);
  493.         tmpfs_name_t *namep = hash_table_get_instance(hlp, tmpfs_name_t,
  494.             link);
  495.  
  496.         (void) ipc_data_read_finalize(callid, namep->name,
  497.             strlen(namep->name) + 1);
  498.         bytes = 1;
  499.     }
  500.  
  501.     /*
  502.      * Answer the VFS_READ call.
  503.      */
  504.     ipc_answer_1(rid, EOK, bytes);
  505. }
  506.  
  507. void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)
  508. {
  509.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  510.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  511.     off_t pos = (off_t)IPC_GET_ARG3(*request);
  512.  
  513.     /*
  514.      * Lookup the respective dentry.
  515.      */
  516.     link_t *hlp;
  517.     unsigned long key = index;
  518.     hlp = hash_table_find(&dentries, &key);
  519.     if (!hlp) {
  520.         ipc_answer_0(rid, ENOENT);
  521.         return;
  522.     }
  523.     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
  524.         dh_link);
  525.  
  526.     /*
  527.      * Receive the write request.
  528.      */
  529.     ipc_callid_t callid;
  530.     size_t len;
  531.     if (!ipc_data_write_receive(&callid, &len)) {
  532.         ipc_answer_0(callid, EINVAL);  
  533.         ipc_answer_0(rid, EINVAL);
  534.         return;
  535.     }
  536.  
  537.     /*
  538.      * Check whether the file needs to grow.
  539.      */
  540.     if (pos + len <= dentry->size) {
  541.         /* The file size is not changing. */
  542.         (void) ipc_data_write_finalize(callid, dentry->data + pos, len);
  543.         ipc_answer_2(rid, EOK, len, dentry->size);
  544.         return;
  545.     }
  546.     size_t delta = (pos + len) - dentry->size;
  547.     /*
  548.      * At this point, we are deliberately extremely straightforward and
  549.      * simply realloc the contents of the file on every write that grows the
  550.      * file. In the end, the situation might not be as bad as it may look:
  551.      * our heap allocator can save us and just grow the block whenever
  552.      * possible.
  553.      */
  554.     void *newdata = realloc(dentry->data, dentry->size + delta);
  555.     if (!newdata) {
  556.         ipc_answer_0(callid, ENOMEM);
  557.         ipc_answer_2(rid, EOK, 0, dentry->size);
  558.         return;
  559.     }
  560.     /* Clear any newly allocated memory in order to emulate gaps. */
  561.     memset(newdata + dentry->size, 0, delta);
  562.     dentry->size += delta;
  563.     dentry->data = newdata;
  564.     (void) ipc_data_write_finalize(callid, dentry->data + pos, len);
  565.     ipc_answer_2(rid, EOK, len, dentry->size);
  566. }
  567.  
  568. void tmpfs_truncate(ipc_callid_t rid, ipc_call_t *request)
  569. {
  570.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  571.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  572.     size_t size = (off_t)IPC_GET_ARG3(*request);
  573.  
  574.     /*
  575.      * Lookup the respective dentry.
  576.      */
  577.     link_t *hlp;
  578.     unsigned long key = index;
  579.     hlp = hash_table_find(&dentries, &key);
  580.     if (!hlp) {
  581.         ipc_answer_0(rid, ENOENT);
  582.         return;
  583.     }
  584.     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
  585.         dh_link);
  586.  
  587.     if (size == dentry->size) {
  588.         ipc_answer_0(rid, EOK);
  589.         return;
  590.     }
  591.  
  592.     void *newdata = realloc(dentry->data, size);
  593.     if (!newdata) {
  594.         ipc_answer_0(rid, ENOMEM);
  595.         return;
  596.     }
  597.     if (size > dentry->size) {
  598.         size_t delta = size - dentry->size;
  599.         memset(newdata + dentry->size, 0, delta);
  600.     }
  601.     dentry->size = size;
  602.     dentry->data = newdata;
  603.     ipc_answer_0(rid, EOK);
  604. }
  605.  
  606. void tmpfs_destroy(ipc_callid_t rid, ipc_call_t *request)
  607. {
  608.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  609.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  610.     int rc;
  611.  
  612.     link_t *hlp;
  613.     unsigned long key = index;
  614.     hlp = hash_table_find(&dentries, &key);
  615.     if (!hlp) {
  616.         ipc_answer_0(rid, ENOENT);
  617.         return;
  618.     }
  619.     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
  620.         dh_link);
  621.     rc = tmpfs_destroy_node(dentry);
  622.     ipc_answer_0(rid, rc);
  623. }
  624.  
  625. /**
  626.  * @}
  627.  */
  628.