SettingLustreProperties.xml

   1 <?xml version='1.0' encoding='UTF-8'?><chapter xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en-US" xml:id="settinglustreproperties">
   2   <title xml:id="settinglustreproperties.title">Setting Lustre Properties in a C Program (<literal>llapi</literal>)</title>
   3   <para>This chapter describes the <literal>llapi</literal> library of commands used for setting Lustre file properties within a C program running in a cluster environment, such as a data processing or MPI application. The commands described in this chapter are:</para>
   4   <itemizedlist>
   5     <listitem>
   6       <para><xref linkend="dbdoclet.50438215_30970"/></para>
   7     </listitem>
   8     <listitem>
   9       <para><xref linkend="dbdoclet.50438215_50149"/></para>
  10     </listitem>
  11     <listitem>
  12       <para><xref linkend="dbdoclet.50438215_86607"/></para>
  13     </listitem>
  14     <listitem>
  15       <para><xref linkend="dbdoclet.50438215_12433"/></para>
  16     </listitem>
  17     <listitem>
  18       <para><xref linkend="dbdoclet.50438215_15718"/></para>
  19     </listitem>
  20   </itemizedlist>
  21   <note>
  22     <para>Lustre programming interface man pages are found in the <literal>lustre/doc</literal> folder.</para>
  23   </note>
  24   <section xml:id="dbdoclet.50438215_30970">
  25     <title>
  26       <literal>llapi_file_create</literal>
  27     </title>
  28     <para>Use <literal>llapi_file_create</literal> to set Lustre properties for a new file.</para>
  29     <section remap="h5">
  30       <title>Synopsis</title>
  31       <screen>#include &lt;lustre/lustreapi.h&gt;
  32
  33 int llapi_file_create(char *name, long stripe_size, int stripe_offset, int stripe_count, int stripe_pattern);
  34 </screen>
  35     </section>
  36     <section remap="h5">
  37       <title>Description</title>
  38       <para>The <literal>llapi_file_create()</literal> function sets a file descriptor&apos;s Lustre
  39         file system striping information. The file descriptor is then accessed with
  40           <literal>open()</literal>.</para>
  41       <informaltable frame="all">
  42         <tgroup cols="2">
  43           <colspec colname="c1" colwidth="50*"/>
  44           <colspec colname="c2" colwidth="50*"/>
  45           <thead>
  46             <row>
  47               <entry>
  48                 <para><emphasis role="bold">Option</emphasis></para>
  49               </entry>
  50               <entry>
  51                 <para><emphasis role="bold">Description</emphasis></para>
  52               </entry>
  53             </row>
  54           </thead>
  55           <tbody>
  56             <row>
  57               <entry>
  58                 <para> <literal>llapi_file_create()</literal></para>
  59               </entry>
  60               <entry>
  61                 <para>If the file already exists, this parameter returns to &apos;<literal>EEXIST</literal>&apos;. If the stripe parameters are invalid, this parameter returns to &apos;<literal>EINVAL</literal>&apos;.</para>
  62               </entry>
  63             </row>
  64             <row>
  65               <entry>
  66                 <para> <literal>stripe_size</literal></para>
  67               </entry>
  68               <entry>
  69                 <para>This value must be an even multiple of system page size, as shown by <literal>getpagesize()</literal>. The default Lustre stripe size is 4MB.</para>
  70               </entry>
  71             </row>
  72             <row>
  73               <entry>
  74                 <para> <literal>stripe_offset</literal></para>
  75               </entry>
  76               <entry>
  77                 <para>Indicates the starting OST for this file.</para>
  78               </entry>
  79             </row>
  80             <row>
  81               <entry>
  82                 <para> <literal>stripe_count</literal></para>
  83               </entry>
  84               <entry>
  85                 <para>Indicates the number of OSTs that this file will be striped across.</para>
  86               </entry>
  87             </row>
  88             <row>
  89               <entry>
  90                 <para> <literal>stripe_pattern</literal></para>
  91               </entry>
  92               <entry>
  93                 <para>Indicates the RAID pattern.</para>
  94               </entry>
  95             </row>
  96           </tbody>
  97         </tgroup>
  98       </informaltable>
  99       <note>
 100         <para>Currently, only RAID 0 is supported. To use the system defaults, set these values: <literal>stripe_size</literal> = 0, <literal>stripe_offset</literal> = -1, <literal>stripe_count</literal> = 0, <literal>stripe_pattern</literal> = 0</para>
 101       </note>
 102     </section>
 103     <section remap="h5">
 104       <title>Examples</title>
 105       <para>System default size is 4 MB.</para>
 106       <screen>char *tfile = TESTFILE;
 107 int stripe_size = 65536</screen>
 108       <para>To start at default, run:</para>
 109       <screen>int stripe_offset = -1</screen>
 110       <para>To start at the default, run:</para>
 111       <screen>int stripe_count = 1</screen>
 112       <para>To set a single stripe for this example, run:</para>
 113       <screen>int stripe_pattern = 0</screen>
 114       <para>Currently, only RAID 0 is supported.</para>
 115       <screen>int stripe_pattern = 0;
 116 int rc, fd;
 117 rc = llapi_file_create(tfile, stripe_size,stripe_offset, stripe_count,stripe_pattern);</screen>
 118       <para>Result code is inverted, you may return with &apos;<literal>EINVAL</literal>&apos; or an ioctl error.</para>
 119       <screen>if (rc) {
 120 fprintf(stderr,&quot;llapi_file_create failed: %d (%s) 0, rc, strerror(-rc));return -1; }</screen>
 121       <para><literal>llapi_file_create</literal> closes the file descriptor. You must re-open the descriptor. To do this, run:</para>
 122       <screen>fd = open(tfile, O_CREAT | O_RDWR | O_LOV_DELAY_CREATE, 0644); if (fd &lt; 0) \ {
 123 fprintf(stderr, &quot;Can&apos;t open %s file: %s0, tfile,
 124 str-
 125 error(errno));
 126 return -1;
 127 }</screen>
 128     </section>
 129   </section>
 130   <section xml:id="dbdoclet.50438215_50149">
 131     <title>llapi_file_get_stripe</title>
 132     <para>Use <literal>llapi_file_get_stripe</literal> to get striping information for a file or directory on a Lustre file system.</para>
 133     <section remap="h5">
 134       <title>Synopsis</title>
 135       <screen>
 136 #include &lt;lustre/lustreapi.h&gt;
 137
 138 int llapi_file_get_stripe(const char *<emphasis>path</emphasis>, void *<emphasis>lum</emphasis>);</screen>
 139     </section>
 140     <section remap="h5">
 141       <title>Description</title>
 142       <para>The <literal>llapi_file_get_stripe()</literal> function returns striping information for a file or directory <emphasis>path</emphasis> in <emphasis>lum</emphasis> (which should point to a large enough memory region) in one of the following formats:</para>
 143       <screen>struct lov_user_md_v1 {
 144 __u32 lmm_magic;
 145 __u32 lmm_pattern;
 146 __u64 lmm_object_id;
 147 __u64 lmm_object_seq;
 148 __u32 lmm_stripe_size;
 149 __u16 lmm_stripe_count;
 150 __u16 lmm_stripe_offset;
 151 struct lov_user_ost_data_v1 lmm_objects[0];
 152 } __attribute__((packed));
 153 struct lov_user_md_v3 {
 154 __u32 lmm_magic;
 155 __u32 lmm_pattern;
 156 __u64 lmm_object_id;
 157 __u64 lmm_object_seq;
 158 __u32 lmm_stripe_size;
 159 __u16 lmm_stripe_count;
 160 __u16 lmm_stripe_offset;
 161 char lmm_pool_name[LOV_MAXPOOLNAME];
 162 struct lov_user_ost_data_v1 lmm_objects[0];
 163 } __attribute__((packed));</screen>
 164       <informaltable frame="all">
 165         <tgroup cols="2">
 166           <colspec colname="c1" colwidth="50*"/>
 167           <colspec colname="c2" colwidth="50*"/>
 168           <thead>
 169             <row>
 170               <entry>
 171                 <para><emphasis role="bold">Option</emphasis></para>
 172               </entry>
 173               <entry>
 174                 <para><emphasis role="bold">Description</emphasis></para>
 175               </entry>
 176             </row>
 177           </thead>
 178           <tbody>
 179             <row>
 180               <entry>
 181                 <para> <literal>lmm_magic</literal></para>
 182               </entry>
 183               <entry>
 184                 <para>Specifies the format of the returned striping information. <literal>LOV_MAGIC_V1</literal> is used for lov_user_md_v1. LOV_MAGIC_V3 is used for <literal>lov_user_md_v3</literal>.</para>
 185               </entry>
 186             </row>
 187             <row>
 188               <entry>
 189                 <para> <literal>lmm_pattern</literal></para>
 190               </entry>
 191               <entry>
 192                 <para>Holds the striping pattern. Only <literal>LOV_PATTERN_RAID0</literal> is
 193                   possible in this Lustre software release.</para>
 194               </entry>
 195             </row>
 196             <row>
 197               <entry>
 198                 <para> <literal>lmm_object_id</literal></para>
 199               </entry>
 200               <entry>
 201                 <para>Holds the MDS object ID.</para>
 202               </entry>
 203             </row>
 204             <row>
 205               <entry>
 206                 <para> <literal>lmm_object_gr</literal></para>
 207               </entry>
 208               <entry>
 209                 <para>Holds the MDS object group.</para>
 210               </entry>
 211             </row>
 212             <row>
 213               <entry>
 214                 <para> <literal>lmm_stripe_size</literal></para>
 215               </entry>
 216               <entry>
 217                 <para>Holds the stripe size in bytes.</para>
 218               </entry>
 219             </row>
 220             <row>
 221               <entry>
 222                 <para> <literal>lmm_stripe_count</literal></para>
 223               </entry>
 224               <entry>
 225                 <para>Holds the number of OSTs over which the file is striped.</para>
 226               </entry>
 227             </row>
 228             <row>
 229               <entry>
 230                 <para> <literal>lmm_stripe_offset</literal></para>
 231               </entry>
 232               <entry>
 233                 <para>Holds the OST index from which the file starts.</para>
 234               </entry>
 235             </row>
 236             <row>
 237               <entry>
 238                 <para> <literal>lmm_pool_name</literal></para>
 239               </entry>
 240               <entry>
 241                 <para>Holds the OST pool name to which the file belongs.</para>
 242               </entry>
 243             </row>
 244             <row>
 245               <entry>
 246                 <para> <literal>lmm_objects</literal></para>
 247               </entry>
 248               <entry>
 249                 <para>An array of <literal>lmm_stripe_count</literal> members containing per OST file information in</para>
 250                 <para>the following format:</para>
 251                 <screen>struct lov_user_ost_data_v1 {
 252                 __u64 l_object_id;
 253                 __u64 l_object_seq;
 254                 __u32 l_ost_gen;
 255                 __u32 l_ost_idx;
 256                 } __attribute__((packed));</screen>
 257               </entry>
 258             </row>
 259             <row>
 260               <entry>
 261                 <para> <literal>l_object_id</literal></para>
 262               </entry>
 263               <entry>
 264                 <para>Holds the OST&apos;s object ID.</para>
 265               </entry>
 266             </row>
 267             <row>
 268               <entry>
 269                 <para> <literal>l_object_seq</literal></para>
 270               </entry>
 271               <entry>
 272                 <para>Holds the OST&apos;s object group.</para>
 273               </entry>
 274             </row>
 275             <row>
 276               <entry>
 277                 <para> <literal>l_ost_gen</literal></para>
 278               </entry>
 279               <entry>
 280                 <para>Holds the OST&apos;s index generation.</para>
 281               </entry>
 282             </row>
 283             <row>
 284               <entry>
 285                 <para> <literal>l_ost_idx</literal></para>
 286               </entry>
 287               <entry>
 288                 <para>Holds the OST&apos;s index in LOV.</para>
 289               </entry>
 290             </row>
 291           </tbody>
 292         </tgroup>
 293       </informaltable>
 294     </section>
 295     <section remap="h5">
 296       <title>Return Values</title>
 297       <para><literal>llapi_file_get_stripe()</literal> returns:</para>
 298       <para><literal>0</literal> On success</para>
 299       <para><literal>!= 0</literal> On failure, <literal>errno</literal> is set appropriately</para>
 300     </section>
 301     <section remap="h5">
 302       <title>Errors</title>
 303       <informaltable frame="all">
 304         <tgroup cols="2">
 305           <colspec colname="c1" colwidth="50*"/>
 306           <colspec colname="c2" colwidth="50*"/>
 307           <thead>
 308             <row>
 309               <entry>
 310                 <para><emphasis role="bold">Errors</emphasis></para>
 311               </entry>
 312               <entry>
 313                 <para><emphasis role="bold">Description</emphasis></para>
 314               </entry>
 315             </row>
 316           </thead>
 317           <tbody>
 318             <row>
 319               <entry>
 320                 <para> <literal>ENOMEM</literal></para>
 321               </entry>
 322               <entry>
 323                 <para>Failed to allocate memory</para>
 324               </entry>
 325             </row>
 326             <row>
 327               <entry>
 328                 <para> <literal>ENAMETOOLONG</literal></para>
 329               </entry>
 330               <entry>
 331                 <para>Path was too long</para>
 332               </entry>
 333             </row>
 334             <row>
 335               <entry>
 336                 <para> <literal>ENOENT</literal></para>
 337               </entry>
 338               <entry>
 339                 <para>Path does not point to a file or directory</para>
 340               </entry>
 341             </row>
 342             <row>
 343               <entry>
 344                 <para> <literal>ENOTTY</literal></para>
 345               </entry>
 346               <entry>
 347                 <para>Path does not point to a Lustre file system</para>
 348               </entry>
 349             </row>
 350             <row>
 351               <entry>
 352                 <para> <literal>EFAULT</literal></para>
 353               </entry>
 354               <entry>
 355                 <para>Memory region pointed by lum is not properly mapped</para>
 356               </entry>
 357             </row>
 358           </tbody>
 359         </tgroup>
 360       </informaltable>
 361     </section>
 362     <section remap="h5">
 363       <title>Examples</title>
 364       <programlisting>
 365 #include &lt;stdio.h&gt;
 366 #include &lt;stdlib.h&gt;
 367 #include &lt;errno.h&gt;
 368 #include &lt;lustre/lustreapi.h&gt;
 369
 370 static inline int maxint(int a, int b)
 371 {
 372         return a &gt; b ? a : b;
 373 }
 374 static void *alloc_lum()
 375 {
 376         int v1, v3, join;
 377         v1 = sizeof(struct lov_user_md_v1) +
 378                 LOV_MAX_STRIPE_COUNT * sizeof(struct lov_user_ost_data_v1);
 379         v3 = sizeof(struct lov_user_md_v3) +
 380                 LOV_MAX_STRIPE_COUNT * sizeof(struct lov_user_ost_data_v1);
 381         return malloc(maxint(v1, v3));
 382 }
 383 int main(int argc, char** argv)
 384 {
 385         struct lov_user_md *lum_file = NULL;
 386         int rc;
 387         int lum_size;
 388         if (argc != 2) {
 389                 fprintf(stderr, &quot;Usage: %s &lt;filename&gt;\n&quot;, argv[0]);
 390                 return 1;
 391         }
 392         lum_file = alloc_lum();
 393         if (lum_file == NULL) {
 394                 rc = ENOMEM;
 395                 goto cleanup;
 396         }
 397         rc = llapi_file_get_stripe(argv[1], lum_file);
 398         if (rc) {
 399                 rc = errno;
 400                 goto cleanup;
 401         }
 402         /* stripe_size stripe_count */
 403         printf(&quot;%d %d\n&quot;,
 404                         lum_file-&gt;lmm_stripe_size,
 405                         lum_file-&gt;lmm_stripe_count);
 406 cleanup:
 407         if (lum_file != NULL)
 408                 free(lum_file);
 409         return rc;
 410 }
 411 </programlisting>
 412     </section>
 413   </section>
 414   <section xml:id="dbdoclet.50438215_86607">
 415     <title>
 416       <literal>llapi_file_open</literal>
 417     </title>
 418     <para>The <literal>llapi_file_open</literal> command opens (or creates) a file or device on a
 419       Lustre file system.</para>
 420     <section remap="h5">
 421       <title>Synopsis</title>
 422       <screen>#include &lt;lustre/lustreapi.h&gt;
 423 int llapi_file_open(const char *<emphasis>name</emphasis>, int <emphasis>flags</emphasis>, int <emphasis>mode</emphasis>,
 424    unsigned long long <emphasis>stripe_size</emphasis>, int <emphasis>stripe_offset</emphasis>,
 425    int <emphasis>stripe_count</emphasis>, int <emphasis>stripe_pattern</emphasis>);
 426 int llapi_file_create(const char *<emphasis>name</emphasis>, unsigned long long <emphasis>stripe_size</emphasis>,
 427    int <emphasis>stripe_offset</emphasis>, int <emphasis>stripe_count</emphasis>,
 428    int <emphasis>stripe_pattern</emphasis>);
 429 </screen>
 430     </section>
 431     <section remap="h5">
 432       <title>Description</title>
 433       <para>The <literal>llapi_file_create()</literal> call is equivalent to the <literal>llapi_file_open</literal> call with <emphasis>flags</emphasis> equal to <literal>O_CREAT|O_WRONLY</literal> and <emphasis>mode</emphasis> equal to <literal>0644</literal>, followed by file close.</para>
 434       <para><literal>llapi_file_open()</literal> opens a file with a given name on a Lustre file
 435         system.</para>
 436       <informaltable frame="all">
 437         <tgroup cols="2">
 438           <colspec colname="c1" colwidth="50*"/>
 439           <colspec colname="c2" colwidth="50*"/>
 440           <thead>
 441             <row>
 442               <entry>
 443                 <para><emphasis role="bold">Option</emphasis></para>
 444               </entry>
 445               <entry>
 446                 <para><emphasis role="bold">Description</emphasis></para>
 447               </entry>
 448             </row>
 449           </thead>
 450           <tbody>
 451             <row>
 452               <entry>
 453                 <para> <literal>flags</literal></para>
 454               </entry>
 455               <entry>
 456                 <para>Can be a combination of <literal>O_RDONLY</literal>, <literal>O_WRONLY</literal>, <literal>O_RDWR</literal>, <literal>O_CREAT</literal>, <literal>O_EXCL</literal>, <literal>O_NOCTTY</literal>, <literal>O_TRUNC</literal>, <literal>O_APPEND</literal>, <literal>O_NONBLOCK</literal>, <literal>O_SYNC</literal>, <literal>FASYNC</literal>, <literal>O_DIRECT</literal>, <literal>O_LARGEFILE</literal>, <literal>O_DIRECTORY</literal>, <literal>O_NOFOLLOW</literal>, <literal>O_NOATIME</literal>.</para>
 457               </entry>
 458             </row>
 459             <row>
 460               <entry>
 461                 <para> <literal>mode</literal></para>
 462               </entry>
 463               <entry>
 464                 <para>Specifies the permission bits to be used for a new file when <literal>O_CREAT</literal> is used.</para>
 465               </entry>
 466             </row>
 467             <row>
 468               <entry>
 469                 <para> <literal>stripe_size</literal></para>
 470               </entry>
 471               <entry>
 472                 <para>Specifies stripe size (in bytes). Should be multiple of 64 KB, not exceeding 4 GB.</para>
 473               </entry>
 474             </row>
 475             <row>
 476               <entry>
 477                 <para> <literal>stripe_offset</literal></para>
 478               </entry>
 479               <entry>
 480                 <para>Specifies an OST index from which the file should start. The default value is -1.</para>
 481               </entry>
 482             </row>
 483             <row>
 484               <entry>
 485                 <para> <literal>stripe_count</literal></para>
 486               </entry>
 487               <entry>
 488                 <para>Specifies the number of OSTs to stripe the file across. The default value is -1.</para>
 489               </entry>
 490             </row>
 491             <row>
 492               <entry>
 493                 <para> <literal>stripe_pattern</literal></para>
 494               </entry>
 495               <entry>
 496                 <para>Specifies the striping pattern. In this release of the Lustre software, only
 497                     <literal>LOV_PATTERN_RAID0</literal> is available. The default value is
 498                   0.</para>
 499               </entry>
 500             </row>
 501           </tbody>
 502         </tgroup>
 503       </informaltable>
 504     </section>
 505     <section remap="h5">
 506       <title>Return Values</title>
 507       <para><literal>llapi_file_open()</literal> and <literal>llapi_file_create()</literal> return:</para>
 508       <para><literal>&gt;=0</literal> On success, for <literal>llapi_file_open</literal> the return value is a file descriptor</para>
 509       <para><literal>&lt;0</literal> On failure, the absolute value is an error code</para>
 510     </section>
 511     <section remap="h5">
 512       <title>Errors</title>
 513       <informaltable frame="all">
 514         <tgroup cols="2">
 515           <colspec colname="c1" colwidth="50*"/>
 516           <colspec colname="c2" colwidth="50*"/>
 517           <thead>
 518             <row>
 519               <entry>
 520                 <para><emphasis role="bold">Errors</emphasis></para>
 521               </entry>
 522               <entry>
 523                 <para><emphasis role="bold">Description</emphasis></para>
 524               </entry>
 525             </row>
 526           </thead>
 527           <tbody>
 528             <row>
 529               <entry>
 530                 <para> <literal>EINVAL</literal></para>
 531               </entry>
 532               <entry>
 533                 <para><literal>stripe_size</literal> or <literal>stripe_offset</literal> or <literal>stripe_count</literal> or <literal>stripe_pattern</literal> is invalid.</para>
 534               </entry>
 535             </row>
 536             <row>
 537               <entry>
 538                 <para> <literal>EEXIST</literal></para>
 539               </entry>
 540               <entry>
 541                 <para>Striping information has already been set and cannot be altered; <literal>name</literal> already exists.</para>
 542               </entry>
 543             </row>
 544             <row>
 545               <entry>
 546                 <para> <literal>EALREADY</literal></para>
 547               </entry>
 548               <entry>
 549                 <para>Striping information has already been set and cannot be altered</para>
 550               </entry>
 551             </row>
 552             <row>
 553               <entry>
 554                 <para> <literal>ENOTTY</literal></para>
 555               </entry>
 556               <entry>
 557                 <para>
 558                   <literal>name</literal> may not point to a Lustre file system.</para>
 559               </entry>
 560             </row>
 561           </tbody>
 562         </tgroup>
 563       </informaltable>
 564     </section>
 565     <section remap="h5">
 566       <title>Example</title>
 567       <programlisting>
 568 #include &lt;stdio.h&gt;
 569 #include &lt;lustre/lustreapi.h&gt;
 570
 571 int main(int argc, char *argv[])
 572 {
 573         int rc;
 574         if (argc != 2)
 575                 return -1;
 576         rc = llapi_file_create(argv[1], 1048576, 0, 2, LOV_PATTERN_RAID0);
 577         if (rc &lt; 0) {
 578                 fprintf(stderr, &quot;file creation has failed, %s\n&quot;,         strerror(-rc));
 579                 return -1;
 580         }
 581         printf(&quot;%s with stripe size 1048576, striped across 2 OSTs,&quot;
 582                         &quot; has been created!\n&quot;, argv[1]);
 583         return 0;
 584 }
 585 </programlisting>
 586     </section>
 587   </section>
 588   <section xml:id="dbdoclet.50438215_12433">
 589     <title>
 590       <literal>llapi_quotactl</literal>
 591     </title>
 592     <para>Use <literal>llapi_quotact</literal>l to manipulate disk quotas on a Lustre file system.</para>
 593     <section remap="h5">
 594       <title>Synopsis</title>
 595       <screen>#include &lt;lustre/lustreapi.h&gt;
 596 int llapi_quotactl(char&quot; &quot; *mnt,&quot; &quot; struct if_quotactl&quot; &quot; *qctl)
 597
 598 struct if_quotactl {
 599         __u32                   qc_cmd;
 600         __u32                   qc_type;
 601         __u32                   qc_id;
 602         __u32                   qc_stat;
 603         struct obd_dqinfo       qc_dqinfo;
 604         struct obd_dqblk        qc_dqblk;
 605         char                    obd_type[16];
 606         struct obd_uuid         obd_uuid;
 607 };
 608 struct obd_dqblk {
 609         __u64 dqb_bhardlimit;
 610         __u64 dqb_bsoftlimit;
 611         __u64 dqb_curspace;
 612         __u64 dqb_ihardlimit;
 613         __u64 dqb_isoftlimit;
 614         __u64 dqb_curinodes;
 615         __u64 dqb_btime;
 616         __u64 dqb_itime;
 617         __u32 dqb_valid;
 618         __u32 padding;
 619 };
 620 struct obd_dqinfo {
 621         __u64 dqi_bgrace;
 622         __u64 dqi_igrace;
 623         __u32 dqi_flags;
 624         __u32 dqi_valid;
 625 };
 626 struct obd_uuid {
 627         char uuid[40];
 628 };</screen>
 629     </section>
 630     <section remap="h5">
 631       <title>Description</title>
 632       <para>The <literal>llapi_quotactl()</literal> command manipulates disk quotas on a Lustre file system mount. qc_cmd indicates a command to be applied to UID <literal>qc_id</literal> or GID <literal>qc_id</literal>.</para>
 633       <informaltable frame="all">
 634         <tgroup cols="2">
 635           <colspec colname="c1" colwidth="50*"/>
 636           <colspec colname="c2" colwidth="50*"/>
 637           <thead>
 638             <row>
 639               <entry>
 640                 <para><emphasis role="bold">Option</emphasis></para>
 641               </entry>
 642               <entry>
 643                 <para><emphasis role="bold">Description</emphasis></para>
 644               </entry>
 645             </row>
 646           </thead>
 647           <tbody>
 648             <row>
 649               <entry>
 650                 <para> <literal>LUSTRE_Q_QUOTAON</literal></para>
 651               </entry>
 652               <entry>
 653                 <para>Turns on quotas for a Lustre file system. Deprecated as of 2.4.0.
 654                     <emphasis>qc_type</emphasis> is <literal>USRQUOTA</literal>,
 655                     <literal>GRPQUOTA</literal> or <literal>UGQUOTA</literal> (both user and group
 656                   quota). The quota files must exist. They are normally created with the
 657                     <literal>llapi_quotacheck</literal> call. This call is restricted to the super
 658                   user privilege. As of 2.4.0, quota is now enabled on a per file system basis via
 659                     <literal>lctl conf_param</literal> (see <xref linkend="enabling_disk_quotas"/>)
 660                   on the MGS node and quotacheck isn't needed any more.</para>
 661               </entry>
 662             </row>
 663             <row>
 664               <entry>
 665                 <para> <literal>LUSTRE_Q_QUOTAOFF</literal></para>
 666               </entry>
 667               <entry>
 668                 <para>Turns off quotas for a Lustre file system. Deprecated as of 2.4.0. <emphasis>qc_type</emphasis> is <literal>USRQUOTA</literal>, <literal>GRPQUOTA</literal> or <literal>UGQUOTA</literal> (both user and group quota). This call is restricted to the super user privilege. As of 2.4.0, quota is disabled via <literal>lctl conf_param</literal> (see <xref linkend="enabling_disk_quotas"/>).</para>
 669               </entry>
 670             </row>
 671             <row>
 672               <entry>
 673                 <para> <literal>LUSTRE_Q_GETQUOTA</literal></para>
 674               </entry>
 675               <entry>
 676                 <para>Gets disk quota limits and current usage for user or group <emphasis>qc_id</emphasis>. <emphasis>qc_type</emphasis> is <literal>USRQUOTA</literal> or <literal>GRPQUOTA</literal>. <emphasis>uuid</emphasis> may be filled with <literal>OBD UUID</literal> string to query quota information from a specific node. <emphasis>dqb_valid</emphasis> may be set nonzero to query information only from MDS. If <emphasis>uuid</emphasis> is an empty string and <emphasis>dqb_valid</emphasis> is zero then cluster-wide limits and usage are returned. On return, <emphasis>obd_dqblk</emphasis> contains the requested information (block limits unit is kilobyte). Quotas must be turned on before using this command.</para>
 677               </entry>
 678             </row>
 679             <row>
 680               <entry>
 681                 <para> <literal>LUSTRE_Q_SETQUOTA</literal></para>
 682               </entry>
 683               <entry>
 684                 <para>Sets disk quota limits for user or group <emphasis>qc_id</emphasis>. <emphasis>qc_type</emphasis> is <literal>USRQUOTA</literal> or <literal>GRPQUOTA</literal>. <emphasis>dqb_valid</emphasis> must be set to <literal>QIF_ILIMITS</literal>, <literal>QIF_BLIMITS</literal> or <literal>QIF_LIMITS</literal> (both inode limits and block limits) dependent on updating limits. <emphasis>obd_dqblk</emphasis> must be filled with limits values (as set in <emphasis>dqb_valid</emphasis>, block limits unit is kilobyte). Quotas must be turned on before using this command.</para>
 685               </entry>
 686             </row>
 687             <row>
 688               <entry>
 689                 <para> <literal>LUSTRE_Q_GETINFO</literal></para>
 690               </entry>
 691               <entry>
 692                 <para>Gets information about quotas. <emphasis>qc_type</emphasis> is either
 693                     <literal>USRQUOTA</literal> or <literal>GRPQUOTA</literal>. On return,
 694                     <emphasis>dqi_igrace</emphasis> is inode grace time (in seconds),
 695                     <emphasis>dqi_bgrace</emphasis> is block grace time (in seconds),
 696                     <emphasis>dqi_flags</emphasis> is not used by the current release of the Lustre
 697                   software.</para>
 698               </entry>
 699             </row>
 700             <row>
 701               <entry>
 702                 <para> <literal>LUSTRE_Q_SETINFO</literal></para>
 703               </entry>
 704               <entry>
 705                 <para>Sets quota information (like grace times). <emphasis>qc_type</emphasis> is
 706                   either <literal>USRQUOTA</literal> or <literal>GRPQUOTA</literal>.
 707                     <emphasis>dqi_igrace</emphasis> is inode grace time (in seconds),
 708                     <emphasis>dqi_bgrace</emphasis> is block grace time (in seconds),
 709                     <emphasis>dqi_flags</emphasis> is not used by the current release of the Lustre
 710                   software and must be zeroed.</para>
 711               </entry>
 712             </row>
 713           </tbody>
 714         </tgroup>
 715       </informaltable>
 716     </section>
 717     <section remap="h5">
 718       <title>Return Values</title>
 719       <para><literal>llapi_quotactl()</literal> returns:</para>
 720       <para><literal>0</literal> On success</para>
 721       <para><literal> -1 </literal> On failure and sets error number (<literal>errno</literal>) to indicate the error</para>
 722     </section>
 723     <section remap="h5">
 724       <title>Errors</title>
 725       <para><literal>llapi_quotactl</literal> errors are described below.</para>
 726       <informaltable frame="all">
 727         <tgroup cols="2">
 728           <colspec colname="c1" colwidth="50*"/>
 729           <colspec colname="c2" colwidth="50*"/>
 730           <thead>
 731             <row>
 732               <entry>
 733                 <para><emphasis role="bold">Errors</emphasis></para>
 734               </entry>
 735               <entry>
 736                 <para><emphasis role="bold">Description</emphasis></para>
 737               </entry>
 738             </row>
 739           </thead>
 740           <tbody>
 741             <row>
 742               <entry>
 743                 <para> <literal>EFAULT</literal></para>
 744               </entry>
 745               <entry>
 746                 <para><emphasis>qctl</emphasis> is invalid.</para>
 747               </entry>
 748             </row>
 749             <row>
 750               <entry>
 751                 <para> <literal>ENOSYS</literal></para>
 752               </entry>
 753               <entry>
 754                 <para>Kernel or Lustre modules have not been compiled with the <literal>QUOTA</literal> option.</para>
 755               </entry>
 756             </row>
 757             <row>
 758               <entry>
 759                 <para> <literal>ENOMEM</literal></para>
 760               </entry>
 761               <entry>
 762                 <para>Insufficient memory to complete operation.</para>
 763               </entry>
 764             </row>
 765             <row>
 766               <entry>
 767                 <para> <literal>ENOTTY</literal></para>
 768               </entry>
 769               <entry>
 770                 <para> <emphasis>qc_cmd</emphasis> is invalid.</para>
 771               </entry>
 772             </row>
 773             <row>
 774               <entry>
 775                 <para> <literal>EBUSY</literal></para>
 776               </entry>
 777               <entry>
 778                 <para>Cannot process during quotacheck.</para>
 779               </entry>
 780             </row>
 781             <row>
 782               <entry>
 783                 <para> <literal>ENOENT</literal></para>
 784               </entry>
 785               <entry>
 786                 <para> <emphasis>uuid</emphasis> does not correspond to OBD or <emphasis>mnt</emphasis> does not exist.</para>
 787               </entry>
 788             </row>
 789             <row>
 790               <entry>
 791                 <para> <literal>EPERM</literal></para>
 792               </entry>
 793               <entry>
 794                 <para>The call is privileged and the caller is not the super user.</para>
 795               </entry>
 796             </row>
 797             <row>
 798               <entry>
 799                 <para> <literal>ESRCH</literal></para>
 800               </entry>
 801               <entry>
 802                 <para>No disk quota is found for the indicated user. Quotas have not been turned on for this file system.</para>
 803               </entry>
 804             </row>
 805           </tbody>
 806         </tgroup>
 807       </informaltable>
 808     </section>
 809   </section>
 810   <section xml:id="dbdoclet.50438215_15718">
 811     <title>
 812       <literal>llapi_path2fid</literal>
 813     </title>
 814     <para>Use <literal>llapi_path2fid</literal> to get the FID from the pathname.</para>
 815     <section remap="h5">
 816       <title>Synopsis</title>
 817       <screen>#include &lt;lustre/lustreapi.h&gt;
 818
 819 int llapi_path2fid(const char *path, unsigned long long *seq, unsigned long *oid, unsigned long *ver)</screen>
 820     </section>
 821     <section remap="h5">
 822       <title>Description</title>
 823       <para>The <literal>llapi_path2fid</literal> function returns the FID (sequence : object ID : version) for the pathname.</para>
 824     </section>
 825     <section remap="h5">
 826       <title>Return Values</title>
 827       <para><literal>llapi_path2fid</literal> returns:</para>
 828       <para><literal>0</literal> On success</para>
 829       <para>non-zero value On failure</para>
 830     </section>
 831   </section>
 832   <section condition="l29">
 833       <title>
 834           <literal>llapi_ladvise</literal>
 835       </title>
 836       <para>Use <literal>llapi_ladvise</literal> to give IO advice/hints on a
 837       Lustre file to the server.</para>
 838       <section remap="h5">
 839           <title>Synopsis</title>
 840           <screen>
 841 #include &lt;lustre/lustreapi.h&gt;
 842 int llapi_ladvise(int fd, unsigned long long flags,
 843                   int num_advise, struct llapi_lu_ladvise *ladvise);
 844
 845 struct llapi_lu_ladvise {
 846   __u16 lla_advice;       /* advice type */
 847   __u16 lla_value1;       /* values for different advice types */
 848   __u32 lla_value2;
 849   __u64 lla_start;        /* first byte of extent for advice */
 850   __u64 lla_end;          /* last byte of extent for advice */
 851   __u32 lla_value3;
 852   __u32 lla_value4;
 853 };
 854           </screen>
 855       </section>
 856       <section remap="h5">
 857           <title>Description</title>
 858           <para>The <literal>llapi_ladvise</literal> function passes an array of
 859           <emphasis>num_advise</emphasis> I/O hints (up to a maximum of
 860           <emphasis>LAH_COUNT_MAX</emphasis> items) in ladvise for the file
 861           descriptor <emphasis>fd</emphasis> from an application to one or more
 862           Lustre servers.  Optionally, <emphasis>flags</emphasis> can modify how
 863           the advice will be processed via bitwise-or'd values:</para>
 864           <itemizedlist><listitem>
 865           <para><literal>LF_ASYNC</literal>:  Clients return to userspace
 866           immediately after submitting ladvise RPCs, leaving server threads to
 867           handle the advices asynchronously.</para>
 868           </listitem></itemizedlist>
 869           <para>Each of the <emphasis>ladvise</emphasis> elements is an
 870           <emphasis>llapi_lu_ladvise</emphasis> structure, which contains the
 871           following fields:
 872           <informaltable frame="all">
 873             <tgroup cols="2">
 874               <colspec colname="c1" colwidth="50*"/>
 875               <colspec colname="c2" colwidth="50*"/>
 876               <thead>
 877                 <row>
 878                   <entry>
 879                     <para><emphasis role="bold">Field</emphasis></para>
 880                   </entry>
 881                   <entry>
 882                     <para><emphasis role="bold">Description</emphasis></para>
 883                   </entry>
 884                 </row>
 885               </thead>
 886               <tbody>
 887               <row>
 888               <entry>
 889                 <para> <literal>lla_ladvice</literal></para>
 890               </entry>
 891               <entry>
 892                 <para>Specifies the advice for the given file range, currently
 893                 one of:</para>
 894                 <para><literal>LU_LADVISE_WILLREAD</literal>:  Prefetch data
 895                 into server cache using optimum I/O size for the server.</para>
 896                 <para><literal>LU_LADVISE_DONTNEED</literal>:  Clean cached data
 897                 for the specified file range(s) on the server.</para>
 898               </entry>
 899               </row>
 900               <row>
 901                 <entry>
 902                   <para> <literal>lla_start</literal></para>
 903                 </entry>
 904                 <entry>
 905                   <para>The offset in bytes for the start of this advice.</para>
 906                 </entry>
 907               </row>
 908               <row>
 909                 <entry>
 910                   <para> <literal>lla_end</literal></para>
 911                 </entry>
 912                 <entry>
 913                   <para>The offset in bytes (non-inclusive) for the end of this
 914                   advice.</para>
 915                 </entry>
 916               </row>
 917               <row>
 918                 <entry>
 919                   <para> <literal>lla_value1</literal></para>
 920                   <para> <literal>lla_value2</literal></para>
 921                   <para> <literal>lla_value3</literal></para>
 922                   <para> <literal>lla_value4</literal></para>
 923                 </entry>
 924                 <entry>
 925                     <para>Additional arguments for future advice types and
 926                     should be set to zero if not explicitly required for a given
 927                     advice type.</para>
 928                 </entry>
 929               </row>
 930               </tbody>
 931               </tgroup>
 932           </informaltable>
 933           </para>
 934           <para><literal>llapi_ladvise()</literal> forwards the advice to Lustre
 935           servers without guaranteeing how and when servers will react to the
 936           advice. Actions may or may not be triggered when the advices are
 937           received, depending on the type of the advice as well as the real-time
 938           decision of the affected server-side components.
 939           </para>
 940           <para> A typical usage of <literal>llapi_ladvise()</literal> is to
 941           enable applications and users (via <literal>lfs ladvise</literal>)
 942           with external knowledge about application I/O patterns to intervene in
 943           server-side I/O handling. For example, if a group of different clients
 944           are doing small random reads of a file, prefetching pages into OSS
 945           cache with big linear reads before the random IO is an overall net
 946           benefit.  Fetching that data into each client cache with
 947           <emphasis>fadvise()</emphasis> may not be beneficial, due to much more
 948           data being sent to the clients.
 949           </para>
 950           <para>While conceptually similar to the
 951           <emphasis>posix_fadvise</emphasis> and Linux
 952           <emphasis>fadvise</emphasis> system calls, the main difference of
 953           <literal>llapi_ladvise()</literal> is that
 954           <emphasis>fadvise() / posix_fadvise()</emphasis> are client side
 955           mechanisms that do not pass advice to the filesystem, while
 956           <literal>llapi_ladvise()</literal> sends advice or hints to one or
 957           more Lustre servers on which the file is stored.  In some cases it may
 958           be desirable to use both interfaces.
 959           </para>
 960       </section>
 961       <section remap="h5">
 962           <title>Return Values</title>
 963           <para><literal>llapi_ladvise</literal> returns:</para>
 964           <para><literal>0</literal> On success</para>
 965           <para><literal>-1</literal> if an error occurred (in which case, errno
 966           is set appropriately).</para>
 967       </section>
 968       <section remap="h5">
 969           <title>Errors</title>
 970         <para>
 971           <informaltable frame="all">
 972             <tgroup cols="2">
 973               <colspec colname="c1" colwidth="50*"/>
 974               <colspec colname="c2" colwidth="50*"/>
 975               <thead>
 976                 <row>
 977                   <entry>
 978                     <para><emphasis role="bold">Error</emphasis></para>
 979                   </entry>
 980                   <entry>
 981                     <para><emphasis role="bold">Description</emphasis></para>
 982                   </entry>
 983                 </row>
 984               </thead>
 985               <tbody>
 986                 <row>
 987                   <entry>
 988                     <para> <literal>ENOMEM</literal></para>
 989                   </entry>
 990                   <entry>
 991                     <para>Insufficient memory to complete operation.</para>
 992                   </entry>
 993                 </row>
 994                 <row>
 995                   <entry>
 996                     <para> <literal>EINVAL</literal></para>
 997                   </entry>
 998                   <entry>
 999                     <para>One or more invalid arguments are given.</para>
1000                   </entry>
1001                 </row>
1002                 <row>
1003                   <entry>
1004                     <para> <literal>EFAULT</literal></para>
1005                   </entry>
1006                   <entry>
1007                     <para>Memory region pointed by
1008                     <literal>ladvise</literal> is not properly mapped.
1009                     </para>
1010                   </entry>
1011                 </row>
1012                 <row>
1013                   <entry>
1014                     <para> <literal>ENOTSUPP</literal></para>
1015                   </entry>
1016                   <entry>
1017                     <para>Advice type is not supported.</para>
1018                   </entry>
1019                 </row>
1020               </tbody>
1021             </tgroup>
1022           </informaltable>
1023           </para>
1024       </section>
1025   </section>
1026   <section xml:id="dbdoclet.50438215_marker-1297700">
1027     <title>Example Using the <literal>llapi</literal> Library</title>
1028     <para>Use <literal>llapi_file_create</literal> to set Lustre software properties for a new file.
1029       For a synopsis and description of <literal>llapi_file_create</literal> and examples of how to
1030       use it, see <xref linkend="configurationfilesmoduleparameters"/>.</para>
1031     <para>You can set striping from inside programs like <literal>ioctl</literal>. To compile the sample program, you need to install the Lustre client source RPM.</para>
1032     <para><emphasis role="bold">A simple C program to demonstrate striping API - libtest.c</emphasis></para>
1033     <programlisting>
1034 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
1035  * vim:expandtab:shiftwidth=8:tabstop=8:
1036  *
1037  * lustredemo - a simple example of lustreapi functions
1038  */
1039 #include &lt;stdio.h&gt;
1040 #include &lt;fcntl.h&gt;
1041 #include &lt;dirent.h&gt;
1042 #include &lt;errno.h&gt;
1043 #include &lt;stdlib.h&gt;
1044 #include &lt;lustre/lustreapi.h&gt;
1045 #define MAX_OSTS 1024
1046 #define LOV_EA_SIZE(lum, num) (sizeof(*lum) + num * sizeof(*lum-&gt;lmm_objects))
1047 #define LOV_EA_MAX(lum) LOV_EA_SIZE(lum, MAX_OSTS)
1048
1049 /*
1050  * This program provides crude examples of using the lustreapi API functions
1051  */
1052 /* Change these definitions to suit */
1053
1054 #define TESTDIR &quot;/tmp&quot;           /* Results directory */
1055 #define TESTFILE &quot;lustre_dummy&quot;  /* Name for the file we create/destroy */
1056 #define FILESIZE 262144                    /* Size of the file in words */
1057 #define DUMWORD &quot;DEADBEEF&quot;       /* Dummy word used to fill files */
1058 #define MY_STRIPE_WIDTH 2                  /* Set this to the number of OST required */
1059 #define MY_LUSTRE_DIR &quot;/mnt/lustre/ftest&quot;
1060
1061 int close_file(int fd)
1062 {
1063         if (close(fd) &lt; 0) {
1064                 fprintf(stderr, &quot;File close failed: %d (%s)\n&quot;, errno, strerror(errno));
1065                 return -1;
1066         }
1067         return 0;
1068 }
1069
1070 int write_file(int fd)
1071 {
1072         char *stng =  DUMWORD;
1073         int cnt = 0;
1074
1075         for( cnt = 0; cnt &lt; FILESIZE; cnt++) {
1076                 write(fd, stng, sizeof(stng));
1077         }
1078         return 0;
1079 }
1080 /* Open a file, set a specific stripe count, size and starting OST
1081  *    Adjust the parameters to suit */
1082 int open_stripe_file()
1083 {
1084         char *tfile = TESTFILE;
1085         int stripe_size = 65536;    /* System default is 4M */
1086         int stripe_offset = -1;     /* Start at default */
1087         int stripe_count = MY_STRIPE_WIDTH;  /*Single stripe for this demo*/
1088         int stripe_pattern = 0;     /* only RAID 0 at this time */
1089         int rc, fd;
1090
1091         rc = llapi_file_create(tfile,
1092                         stripe_size,stripe_offset,stripe_count,stripe_pattern);
1093         /* result code is inverted, we may return -EINVAL or an ioctl error.
1094          * We borrow an error message from sanity.c
1095          */
1096         if (rc) {
1097                 fprintf(stderr,&quot;llapi_file_create failed: %d (%s) \n&quot;, rc, strerror(-rc));
1098                 return -1;
1099         }
1100         /* llapi_file_create closes the file descriptor, we must re-open */
1101         fd = open(tfile, O_CREAT | O_RDWR | O_LOV_DELAY_CREATE, 0644);
1102         if (fd &lt; 0) {
1103                 fprintf(stderr, &quot;Can't open %s file: %d (%s)\n&quot;, tfile, errno, strerror(errno));
1104                 return -1;
1105         }
1106         return fd;
1107 }
1108
1109 /* output a list of uuids for this file */
1110 int get_my_uuids(int fd)
1111 {
1112         struct obd_uuid uuids[1024], *uuidp;        /* Output var */
1113         int obdcount = 1024;
1114         int rc,i;
1115
1116         rc = llapi_lov_get_uuids(fd, uuids, &amp;obdcount);
1117         if (rc != 0) {
1118                 fprintf(stderr, &quot;get uuids failed: %d (%s)\n&quot;,errno, strerror(errno));
1119         }
1120         printf(&quot;This file system has %d obds\n&quot;, obdcount);
1121         for (i = 0, uuidp = uuids; i &lt; obdcount; i++, uuidp++) {
1122                 printf(&quot;UUID %d is %s\n&quot;,i, uuidp-&gt;uuid);
1123         }
1124         return 0;
1125 }
1126
1127 /* Print out some LOV attributes. List our objects */
1128 int get_file_info(char *path)
1129 {
1130
1131         struct lov_user_md *lump;
1132         int rc;
1133         int i;
1134
1135         lump = malloc(LOV_EA_MAX(lump));
1136         if (lump == NULL) {
1137                 return -1;
1138         }
1139
1140         rc = llapi_file_get_stripe(path, lump);
1141
1142         if (rc != 0) {
1143                 fprintf(stderr, &quot;get_stripe failed: %d (%s)\n&quot;,errno, strerror(errno));
1144                 return -1;
1145         }
1146
1147         printf(&quot;Lov magic %u\n&quot;, lump-&gt;lmm_magic);
1148         printf(&quot;Lov pattern %u\n&quot;, lump-&gt;lmm_pattern);
1149         printf(&quot;Lov object id %llu\n&quot;, lump-&gt;lmm_object_id);
1150         printf(&quot;Lov stripe size %u\n&quot;, lump-&gt;lmm_stripe_size);
1151         printf(&quot;Lov stripe count %hu\n&quot;, lump-&gt;lmm_stripe_count);
1152         printf(&quot;Lov stripe offset %u\n&quot;, lump-&gt;lmm_stripe_offset);
1153         for (i = 0; i &lt; lump-&gt;lmm_stripe_count; i++) {
1154                 printf(&quot;Object index %d Objid %llu\n&quot;, lump-&gt;lmm_objects[i].l_ost_idx, lump-&gt;lmm_objects[i].l_object_id);
1155         }
1156
1157         free(lump);
1158         return rc;
1159
1160 }
1161
1162 /* Ping all OSTs that belong to this filesystem */
1163 int ping_osts()
1164 {
1165         DIR *dir;
1166         struct dirent *d;
1167         char osc_dir[100];
1168         int rc;
1169
1170         sprintf(osc_dir, &quot;/proc/fs/lustre/osc&quot;);
1171         dir = opendir(osc_dir);
1172         if (dir == NULL) {
1173                 printf(&quot;Can't open dir\n&quot;);
1174                 return -1;
1175         }
1176         while((d = readdir(dir)) != NULL) {
1177                 if ( d-&gt;d_type == DT_DIR ) {
1178                         if (! strncmp(d-&gt;d_name, &quot;OSC&quot;, 3)) {
1179                                 printf(&quot;Pinging OSC %s &quot;, d-&gt;d_name);
1180                                 rc = llapi_ping(&quot;osc&quot;, d-&gt;d_name);
1181                                 if (rc) {
1182                                         printf(&quot;  bad\n&quot;);
1183                                 } else {
1184                                         printf(&quot;  good\n&quot;);
1185                                 }
1186                         }
1187                 }
1188         }
1189         return 0;
1190
1191 }
1192
1193 int main()
1194 {
1195         int file;
1196         int rc;
1197         char filename[100];
1198         char sys_cmd[100];
1199
1200         sprintf(filename, &quot;%s/%s&quot;,MY_LUSTRE_DIR, TESTFILE);
1201
1202         printf(&quot;Open a file with striping\n&quot;);
1203         file = open_stripe_file();
1204         if ( file &lt; 0 ) {
1205                 printf(&quot;Exiting\n&quot;);
1206                 exit(1);
1207         }
1208         printf(&quot;Getting uuid list\n&quot;);
1209         rc = get_my_uuids(file);
1210         printf(&quot;Write to the file\n&quot;);
1211         rc = write_file(file);
1212         rc = close_file(file);
1213         printf(&quot;Listing LOV data\n&quot;);
1214         rc = get_file_info(filename);
1215         printf(&quot;Ping our OSTs\n&quot;);
1216         rc = ping_osts();
1217
1218         /* the results should match lfs getstripe */
1219         printf(&quot;Confirming our results with lfs getstripe\n&quot;);
1220         sprintf(sys_cmd, &quot;/usr/bin/lfs getstripe %s/%s&quot;, MY_LUSTRE_DIR, TESTFILE);
1221         system(sys_cmd);
1222
1223         printf(&quot;All done\n&quot;);
1224         exit(rc);
1225 }
1226 </programlisting>
1227     <para><emphasis role="bold">Makefile for sample application:</emphasis></para>
1228     <screen>
1229 gcc -g -O2 -Wall -o lustredemo libtest.c -llustreapi
1230 clean:
1231 rm -f core lustredemo *.o
1232 run:
1233 make
1234 rm -f /mnt/lustre/ftest/lustredemo
1235 rm -f /mnt/lustre/ftest/lustre_dummy
1236 cp lustredemo /mnt/lustre/ftest/
1237 </screen>
1238     <section remap="h5">
1239       <title>See Also</title>
1240       <itemizedlist>
1241         <listitem>
1242           <para>
1243             <xref linkend="dbdoclet.50438215_30970"/>
1244     </para>
1245         </listitem>
1246         <listitem>
1247           <para>
1248             <xref linkend="dbdoclet.50438215_50149"/>
1249     </para>
1250         </listitem>
1251         <listitem>
1252           <para>
1253             <xref linkend="dbdoclet.50438215_86607"/>
1254     </para>
1255         </listitem>
1256         <listitem>
1257           <para>
1258             <xref linkend="dbdoclet.50438215_12433"/>
1259     </para>
1260         </listitem>
1261       </itemizedlist>
1262     </section>
1263   </section>
1264 </chapter>