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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 NODES_BUCKETS   256
  58.  
  59. /** All root nodes have index 0. */
  60. #define TMPFS_SOME_ROOT     0
  61. /** Global counter for assigning node indices. Shared by all instances. */
  62. fs_index_t tmpfs_next_index = 1;
  63.  
  64. /*
  65.  * Implementation of the libfs interface.
  66.  */
  67.  
  68. /* Forward declarations of static functions. */
  69. static fs_node_t *tmpfs_match(fs_node_t *, const char *);
  70. static fs_node_t *tmpfs_node_get(dev_handle_t, fs_index_t);
  71. static void tmpfs_node_put(fs_node_t *);
  72. static fs_node_t *tmpfs_create_node(dev_handle_t, int);
  73. static int tmpfs_link_node(fs_node_t *, fs_node_t *, const char *);
  74. static int tmpfs_unlink_node(fs_node_t *, fs_node_t *, const char *);
  75. static int tmpfs_destroy_node(fs_node_t *);
  76.  
  77. /* Implementation of helper functions. */
  78. static fs_index_t tmpfs_index_get(fs_node_t *fn)
  79. {
  80.     return TMPFS_NODE(fn)->index;
  81. }
  82.  
  83. static size_t tmpfs_size_get(fs_node_t *fn)
  84. {
  85.     return TMPFS_NODE(fn)->size;
  86. }
  87.  
  88. static unsigned tmpfs_lnkcnt_get(fs_node_t *fn)
  89. {
  90.     return TMPFS_NODE(fn)->lnkcnt;
  91. }
  92.  
  93. static bool tmpfs_has_children(fs_node_t *fn)
  94. {
  95.     return !list_empty(&TMPFS_NODE(fn)->cs_head);
  96. }
  97.  
  98. static fs_node_t *tmpfs_root_get(dev_handle_t dev_handle)
  99. {
  100.     return tmpfs_node_get(dev_handle, TMPFS_SOME_ROOT);
  101. }
  102.  
  103. static char tmpfs_plb_get_char(unsigned pos)
  104. {
  105.     return tmpfs_reg.plb_ro[pos % PLB_SIZE];
  106. }
  107.  
  108. static bool tmpfs_is_directory(fs_node_t *fn)
  109. {
  110.     return TMPFS_NODE(fn)->type == TMPFS_DIRECTORY;
  111. }
  112.  
  113. static bool tmpfs_is_file(fs_node_t *fn)
  114. {
  115.     return TMPFS_NODE(fn)->type == TMPFS_FILE;
  116. }
  117.  
  118. /** libfs operations */
  119. libfs_ops_t tmpfs_libfs_ops = {
  120.     .match = tmpfs_match,
  121.     .node_get = tmpfs_node_get,
  122.     .node_put = tmpfs_node_put,
  123.     .create = tmpfs_create_node,
  124.     .destroy = tmpfs_destroy_node,
  125.     .link = tmpfs_link_node,
  126.     .unlink = tmpfs_unlink_node,
  127.     .index_get = tmpfs_index_get,
  128.     .size_get = tmpfs_size_get,
  129.     .lnkcnt_get = tmpfs_lnkcnt_get,
  130.     .has_children = tmpfs_has_children,
  131.     .root_get = tmpfs_root_get,
  132.     .plb_get_char = tmpfs_plb_get_char,
  133.     .is_directory = tmpfs_is_directory,
  134.     .is_file = tmpfs_is_file
  135. };
  136.  
  137. /** Hash table of all TMPFS nodes. */
  138. hash_table_t nodes;
  139.  
  140. #define NODES_KEY_INDEX 0
  141. #define NODES_KEY_DEV   1
  142.  
  143. /* Implementation of hash table interface for the nodes hash table. */
  144. static hash_index_t nodes_hash(unsigned long key[])
  145. {
  146.     return key[NODES_KEY_INDEX] % NODES_BUCKETS;
  147. }
  148.  
  149. static int nodes_compare(unsigned long key[], hash_count_t keys, link_t *item)
  150. {
  151.     tmpfs_node_t *nodep = hash_table_get_instance(item, tmpfs_node_t,
  152.         nh_link);
  153.     return (nodep->index == key[NODES_KEY_INDEX] &&
  154.         nodep->dev_handle == key[NODES_KEY_DEV]);
  155. }
  156.  
  157. static void nodes_remove_callback(link_t *item)
  158. {
  159. }
  160.  
  161. /** TMPFS nodes hash table operations. */
  162. hash_table_operations_t nodes_ops = {
  163.     .hash = nodes_hash,
  164.     .compare = nodes_compare,
  165.     .remove_callback = nodes_remove_callback
  166. };
  167.  
  168. static void tmpfs_node_initialize(tmpfs_node_t *nodep)
  169. {
  170.     nodep->bp = NULL;
  171.     nodep->index = 0;
  172.     nodep->dev_handle = 0;
  173.     nodep->type = TMPFS_NONE;
  174.     nodep->lnkcnt = 0;
  175.     nodep->size = 0;
  176.     nodep->data = NULL;
  177.     link_initialize(&nodep->nh_link);
  178.     list_initialize(&nodep->cs_head);
  179. }
  180.  
  181. static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentryp)
  182. {
  183.     link_initialize(&dentryp->link);
  184.     dentryp->name = NULL;
  185.     dentryp->node = NULL;
  186. }
  187.  
  188. bool tmpfs_init(void)
  189. {
  190.     if (!hash_table_create(&nodes, NODES_BUCKETS, 2, &nodes_ops))
  191.         return false;
  192.    
  193.     return true;
  194. }
  195.  
  196. static bool tmpfs_instance_init(dev_handle_t dev_handle)
  197. {
  198.     fs_node_t *rfn;
  199.    
  200.     rfn = tmpfs_create_node(dev_handle, L_DIRECTORY);
  201.     if (!rfn)
  202.         return false;
  203.     TMPFS_NODE(rfn)->lnkcnt = 0;    /* FS root is not linked */
  204.     return true;
  205. }
  206.  
  207. fs_node_t *tmpfs_match(fs_node_t *pfn, const char *component)
  208. {
  209.     tmpfs_node_t *parentp = TMPFS_NODE(pfn);
  210.     link_t *lnk;
  211.  
  212.     for (lnk = parentp->cs_head.next; lnk != &parentp->cs_head;
  213.         lnk = lnk->next) {
  214.         tmpfs_dentry_t *dentryp = list_get_instance(lnk, tmpfs_dentry_t,
  215.             link);
  216.         if (!str_cmp(dentryp->name, component))
  217.             return FS_NODE(dentryp->node);
  218.     }
  219.  
  220.     return NULL;
  221. }
  222.  
  223. fs_node_t *tmpfs_node_get(dev_handle_t dev_handle, fs_index_t index)
  224. {
  225.     unsigned long key[] = {
  226.         [NODES_KEY_INDEX] = index,
  227.         [NODES_KEY_DEV] = dev_handle
  228.     };
  229.     link_t *lnk = hash_table_find(&nodes, key);
  230.     if (!lnk)
  231.         return NULL;
  232.     return FS_NODE(hash_table_get_instance(lnk, tmpfs_node_t, nh_link));
  233. }
  234.  
  235. void tmpfs_node_put(fs_node_t *fn)
  236. {
  237.     /* nothing to do */
  238. }
  239.  
  240. fs_node_t *tmpfs_create_node(dev_handle_t dev_handle, int lflag)
  241. {
  242.     assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));
  243.  
  244.     tmpfs_node_t *nodep = malloc(sizeof(tmpfs_node_t));
  245.     if (!nodep)
  246.         return NULL;
  247.     tmpfs_node_initialize(nodep);
  248.     nodep->bp = malloc(sizeof(fs_node_t));
  249.     if (!nodep->bp) {
  250.         free(nodep);
  251.         return NULL;
  252.     }
  253.     fs_node_initialize(nodep->bp);
  254.     nodep->bp->data = nodep;    /* link the FS and TMPFS nodes */
  255.     if (!tmpfs_root_get(dev_handle))
  256.         nodep->index = TMPFS_SOME_ROOT;
  257.     else
  258.         nodep->index = tmpfs_next_index++;
  259.     nodep->dev_handle = dev_handle;
  260.     if (lflag & L_DIRECTORY)
  261.         nodep->type = TMPFS_DIRECTORY;
  262.     else
  263.         nodep->type = TMPFS_FILE;
  264.  
  265.     /* Insert the new node into the nodes hash table. */
  266.     unsigned long key[] = {
  267.         [NODES_KEY_INDEX] = nodep->index,
  268.         [NODES_KEY_DEV] = nodep->dev_handle
  269.     };
  270.     hash_table_insert(&nodes, key, &nodep->nh_link);
  271.     return FS_NODE(nodep);
  272. }
  273.  
  274. int tmpfs_link_node(fs_node_t *pfn, fs_node_t *cfn, const char *nm)
  275. {
  276.     tmpfs_node_t *parentp = TMPFS_NODE(pfn);
  277.     tmpfs_node_t *childp = TMPFS_NODE(cfn);
  278.     tmpfs_dentry_t *dentryp;
  279.     link_t *lnk;
  280.  
  281.     assert(parentp->type == TMPFS_DIRECTORY);
  282.  
  283.     /* Check for duplicit entries. */
  284.     for (lnk = parentp->cs_head.next; lnk != &parentp->cs_head;
  285.         lnk = lnk->next) {
  286.         dentryp = list_get_instance(lnk, tmpfs_dentry_t, link);
  287.         if (!str_cmp(dentryp->name, nm))
  288.             return EEXIST;
  289.     }
  290.  
  291.     /* Allocate and initialize the dentry. */
  292.     dentryp = malloc(sizeof(tmpfs_dentry_t));
  293.     if (!dentryp)
  294.         return ENOMEM;
  295.     tmpfs_dentry_initialize(dentryp);
  296.  
  297.     /* Populate and link the new dentry. */
  298.     size_t size = str_size(nm);
  299.     dentryp->name = malloc(size + 1);
  300.     if (!dentryp->name) {
  301.         free(dentryp);
  302.         return ENOMEM;
  303.     }
  304.     str_cpy(dentryp->name, size + 1, nm);
  305.     dentryp->node = childp;
  306.     childp->lnkcnt++;
  307.     list_append(&dentryp->link, &parentp->cs_head);
  308.  
  309.     return EOK;
  310. }
  311.  
  312. int tmpfs_unlink_node(fs_node_t *pfn, fs_node_t *cfn, const char *nm)
  313. {
  314.     tmpfs_node_t *parentp = TMPFS_NODE(pfn);
  315.     tmpfs_node_t *childp = NULL;
  316.     tmpfs_dentry_t *dentryp;
  317.     link_t *lnk;
  318.  
  319.     if (!parentp)
  320.         return EBUSY;
  321.    
  322.     for (lnk = parentp->cs_head.next; lnk != &parentp->cs_head;
  323.         lnk = lnk->next) {
  324.         dentryp = list_get_instance(lnk, tmpfs_dentry_t, link);
  325.         if (!str_cmp(dentryp->name, nm)) {
  326.             childp = dentryp->node;
  327.             assert(FS_NODE(childp) == cfn);
  328.             break;
  329.         }  
  330.     }
  331.  
  332.     if (!childp)
  333.         return ENOENT;
  334.        
  335.     if ((childp->lnkcnt == 1) && !list_empty(&childp->cs_head))
  336.         return ENOTEMPTY;
  337.  
  338.     list_remove(&dentryp->link);
  339.     free(dentryp);
  340.     childp->lnkcnt--;
  341.  
  342.     return EOK;
  343. }
  344.  
  345. int tmpfs_destroy_node(fs_node_t *fn)
  346. {
  347.     tmpfs_node_t *nodep = TMPFS_NODE(fn);
  348.    
  349.     assert(!nodep->lnkcnt);
  350.     assert(list_empty(&nodep->cs_head));
  351.  
  352.     unsigned long key[] = {
  353.         [NODES_KEY_INDEX] = nodep->index,
  354.         [NODES_KEY_DEV] = nodep->dev_handle
  355.     };
  356.     hash_table_remove(&nodes, key, 2);
  357.  
  358.     if (nodep->type == TMPFS_FILE)
  359.         free(nodep->data);
  360.     free(nodep->bp);
  361.     free(nodep);
  362.     return EOK;
  363. }
  364.  
  365. void tmpfs_mounted(ipc_callid_t rid, ipc_call_t *request)
  366. {
  367.     dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
  368.  
  369.     /* accept the mount options */
  370.     ipc_callid_t callid;
  371.     size_t size;
  372.     if (!ipc_data_write_receive(&callid, &size)) {
  373.         ipc_answer_0(callid, EINVAL);
  374.         ipc_answer_0(rid, EINVAL);
  375.         return;
  376.     }
  377.     char *opts = malloc(size + 1);
  378.     if (!opts) {
  379.         ipc_answer_0(callid, ENOMEM);
  380.         ipc_answer_0(rid, ENOMEM);
  381.         return;
  382.     }
  383.     ipcarg_t retval = ipc_data_write_finalize(callid, opts, size);
  384.     if (retval != EOK) {
  385.         ipc_answer_0(rid, retval);
  386.         free(opts);
  387.         return;
  388.     }
  389.     opts[size] = '\0';
  390.  
  391.     /* Initialize TMPFS instance. */
  392.     if (!tmpfs_instance_init(dev_handle)) {
  393.         ipc_answer_0(rid, ENOMEM);
  394.         return;
  395.     }
  396.  
  397.     tmpfs_node_t *rootp = TMPFS_NODE(tmpfs_root_get(dev_handle));
  398.     if (str_cmp(opts, "restore") == 0) {
  399.         if (tmpfs_restore(dev_handle))
  400.             ipc_answer_3(rid, EOK, rootp->index, rootp->size,
  401.                 rootp->lnkcnt);
  402.         else
  403.             ipc_answer_0(rid, ELIMIT);
  404.     } else {
  405.         ipc_answer_3(rid, EOK, rootp->index, rootp->size,
  406.             rootp->lnkcnt);
  407.     }
  408. }
  409.  
  410. void tmpfs_mount(ipc_callid_t rid, ipc_call_t *request)
  411. {
  412.     libfs_mount(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request);
  413. }
  414.  
  415. void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
  416. {
  417.     libfs_lookup(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request);
  418. }
  419.  
  420. void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)
  421. {
  422.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  423.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  424.     off_t pos = (off_t)IPC_GET_ARG3(*request);
  425.  
  426.     /*
  427.      * Lookup the respective TMPFS node.
  428.      */
  429.     link_t *hlp;
  430.     unsigned long key[] = {
  431.         [NODES_KEY_INDEX] = index,
  432.         [NODES_KEY_DEV] = dev_handle,
  433.     };
  434.     hlp = hash_table_find(&nodes, key);
  435.     if (!hlp) {
  436.         ipc_answer_0(rid, ENOENT);
  437.         return;
  438.     }
  439.     tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
  440.         nh_link);
  441.  
  442.     /*
  443.      * Receive the read request.
  444.      */
  445.     ipc_callid_t callid;
  446.     size_t size;
  447.     if (!ipc_data_read_receive(&callid, &size)) {
  448.         ipc_answer_0(callid, EINVAL);  
  449.         ipc_answer_0(rid, EINVAL);
  450.         return;
  451.     }
  452.  
  453.     size_t bytes;
  454.     if (nodep->type == TMPFS_FILE) {
  455.         bytes = max(0, min(nodep->size - pos, size));
  456.         (void) ipc_data_read_finalize(callid, nodep->data + pos,
  457.             bytes);
  458.     } else {
  459.         tmpfs_dentry_t *dentryp;
  460.         link_t *lnk;
  461.         int i;
  462.        
  463.         assert(nodep->type == TMPFS_DIRECTORY);
  464.        
  465.         /*
  466.          * Yes, we really use O(n) algorithm here.
  467.          * If it bothers someone, it could be fixed by introducing a
  468.          * hash table.
  469.          */
  470.         for (i = 0, lnk = nodep->cs_head.next;
  471.             i < pos && lnk != &nodep->cs_head;
  472.             i++, lnk = lnk->next)
  473.             ;
  474.  
  475.         if (lnk == &nodep->cs_head) {
  476.             ipc_answer_0(callid, ENOENT);
  477.             ipc_answer_1(rid, ENOENT, 0);
  478.             return;
  479.         }
  480.  
  481.         dentryp = list_get_instance(lnk, tmpfs_dentry_t, link);
  482.  
  483.         (void) ipc_data_read_finalize(callid, dentryp->name,
  484.             str_size(dentryp->name) + 1);
  485.         bytes = 1;
  486.     }
  487.  
  488.     /*
  489.      * Answer the VFS_READ call.
  490.      */
  491.     ipc_answer_1(rid, EOK, bytes);
  492. }
  493.  
  494. void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)
  495. {
  496.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  497.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  498.     off_t pos = (off_t)IPC_GET_ARG3(*request);
  499.  
  500.     /*
  501.      * Lookup the respective TMPFS node.
  502.      */
  503.     link_t *hlp;
  504.     unsigned long key[] = {
  505.         [NODES_KEY_INDEX] = index,
  506.         [NODES_KEY_DEV] = dev_handle
  507.     };
  508.     hlp = hash_table_find(&nodes, key);
  509.     if (!hlp) {
  510.         ipc_answer_0(rid, ENOENT);
  511.         return;
  512.     }
  513.     tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
  514.         nh_link);
  515.  
  516.     /*
  517.      * Receive the write request.
  518.      */
  519.     ipc_callid_t callid;
  520.     size_t size;
  521.     if (!ipc_data_write_receive(&callid, &size)) {
  522.         ipc_answer_0(callid, EINVAL);  
  523.         ipc_answer_0(rid, EINVAL);
  524.         return;
  525.     }
  526.  
  527.     /*
  528.      * Check whether the file needs to grow.
  529.      */
  530.     if (pos + size <= nodep->size) {
  531.         /* The file size is not changing. */
  532.         (void) ipc_data_write_finalize(callid, nodep->data + pos, size);
  533.         ipc_answer_2(rid, EOK, size, nodep->size);
  534.         return;
  535.     }
  536.     size_t delta = (pos + size) - nodep->size;
  537.     /*
  538.      * At this point, we are deliberately extremely straightforward and
  539.      * simply realloc the contents of the file on every write that grows the
  540.      * file. In the end, the situation might not be as bad as it may look:
  541.      * our heap allocator can save us and just grow the block whenever
  542.      * possible.
  543.      */
  544.     void *newdata = realloc(nodep->data, nodep->size + delta);
  545.     if (!newdata) {
  546.         ipc_answer_0(callid, ENOMEM);
  547.         ipc_answer_2(rid, EOK, 0, nodep->size);
  548.         return;
  549.     }
  550.     /* Clear any newly allocated memory in order to emulate gaps. */
  551.     memset(newdata + nodep->size, 0, delta);
  552.     nodep->size += delta;
  553.     nodep->data = newdata;
  554.     (void) ipc_data_write_finalize(callid, nodep->data + pos, size);
  555.     ipc_answer_2(rid, EOK, size, nodep->size);
  556. }
  557.  
  558. void tmpfs_truncate(ipc_callid_t rid, ipc_call_t *request)
  559. {
  560.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  561.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  562.     size_t size = (off_t)IPC_GET_ARG3(*request);
  563.  
  564.     /*
  565.      * Lookup the respective TMPFS node.
  566.      */
  567.     link_t *hlp;
  568.     unsigned long key[] = {
  569.         [NODES_KEY_INDEX] = index,
  570.         [NODES_KEY_DEV] = dev_handle
  571.     };
  572.     hlp = hash_table_find(&nodes, key);
  573.     if (!hlp) {
  574.         ipc_answer_0(rid, ENOENT);
  575.         return;
  576.     }
  577.     tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
  578.         nh_link);
  579.  
  580.     if (size == nodep->size) {
  581.         ipc_answer_0(rid, EOK);
  582.         return;
  583.     }
  584.  
  585.     void *newdata = realloc(nodep->data, size);
  586.     if (!newdata) {
  587.         ipc_answer_0(rid, ENOMEM);
  588.         return;
  589.     }
  590.     if (size > nodep->size) {
  591.         size_t delta = size - nodep->size;
  592.         memset(newdata + nodep->size, 0, delta);
  593.     }
  594.     nodep->size = size;
  595.     nodep->data = newdata;
  596.     ipc_answer_0(rid, EOK);
  597. }
  598.  
  599. void tmpfs_destroy(ipc_callid_t rid, ipc_call_t *request)
  600. {
  601.     dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
  602.     fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
  603.     int rc;
  604.  
  605.     link_t *hlp;
  606.     unsigned long key[] = {
  607.         [NODES_KEY_INDEX] = index,
  608.         [NODES_KEY_DEV] = dev_handle
  609.     };
  610.     hlp = hash_table_find(&nodes, key);
  611.     if (!hlp) {
  612.         ipc_answer_0(rid, ENOENT);
  613.         return;
  614.     }
  615.     tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
  616.         nh_link);
  617.     rc = tmpfs_destroy_node(FS_NODE(nodep));
  618.     ipc_answer_0(rid, rc);
  619. }
  620.  
  621. /**
  622.  * @}
  623.  */
  624.