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>
6 <para><xref linkend="dbdoclet.50438215_30970"/></para>
9 <para><xref linkend="dbdoclet.50438215_50149"/></para>
12 <para><xref linkend="dbdoclet.50438215_86607"/></para>
15 <para><xref linkend="dbdoclet.50438215_12433"/></para>
18 <para><xref linkend="dbdoclet.50438215_15718"/></para>
22 <para>Lustre programming interface man pages are found in the <literal>lustre/doc</literal> folder.</para>
24 <section xml:id="dbdoclet.50438215_30970">
26 <literal>llapi_file_create</literal>
28 <para>Use <literal>llapi_file_create</literal> to set Lustre properties for a new file.</para>
30 <title>Synopsis</title>
31 <screen>#include <lustre/lustreapi.h>
33 int llapi_file_create(char *name, long stripe_size, int stripe_offset, int stripe_count, int stripe_pattern);
37 <title>Description</title>
38 <para>The <literal>llapi_file_create()</literal> function sets a file descriptor's Lustre
39 file system striping information. The file descriptor is then accessed with
40 <literal>open()</literal>.</para>
41 <informaltable frame="all">
43 <colspec colname="c1" colwidth="50*"/>
44 <colspec colname="c2" colwidth="50*"/>
48 <para><emphasis role="bold">Option</emphasis></para>
51 <para><emphasis role="bold">Description</emphasis></para>
58 <para> <literal>llapi_file_create()</literal></para>
61 <para>If the file already exists, this parameter returns to '<literal>EEXIST</literal>'. If the stripe parameters are invalid, this parameter returns to '<literal>EINVAL</literal>'.</para>
66 <para> <literal>stripe_size</literal></para>
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>
74 <para> <literal>stripe_offset</literal></para>
77 <para>Indicates the starting OST for this file.</para>
82 <para> <literal>stripe_count</literal></para>
85 <para>Indicates the number of OSTs that this file will be striped across.</para>
90 <para> <literal>stripe_pattern</literal></para>
93 <para>Indicates the RAID pattern.</para>
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>
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;
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 '<literal>EINVAL</literal>' or an ioctl error.</para>
120 fprintf(stderr,"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 < 0) \ {
123 fprintf(stderr, "Can't open %s file: %s0, tfile,
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>
134 <title>Synopsis</title>
136 #include <lustre/lustreapi.h>
138 int llapi_file_get_stripe(const char *<emphasis>path</emphasis>, void *<emphasis>lum</emphasis>);</screen>
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 {
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 {
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">
166 <colspec colname="c1" colwidth="50*"/>
167 <colspec colname="c2" colwidth="50*"/>
171 <para><emphasis role="bold">Option</emphasis></para>
174 <para><emphasis role="bold">Description</emphasis></para>
181 <para> <literal>lmm_magic</literal></para>
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>
189 <para> <literal>lmm_pattern</literal></para>
192 <para>Holds the striping pattern. Only <literal>LOV_PATTERN_RAID0</literal> is
193 possible in this Lustre software release.</para>
198 <para> <literal>lmm_object_id</literal></para>
201 <para>Holds the MDS object ID.</para>
206 <para> <literal>lmm_object_gr</literal></para>
209 <para>Holds the MDS object group.</para>
214 <para> <literal>lmm_stripe_size</literal></para>
217 <para>Holds the stripe size in bytes.</para>
222 <para> <literal>lmm_stripe_count</literal></para>
225 <para>Holds the number of OSTs over which the file is striped.</para>
230 <para> <literal>lmm_stripe_offset</literal></para>
233 <para>Holds the OST index from which the file starts.</para>
238 <para> <literal>lmm_pool_name</literal></para>
241 <para>Holds the OST pool name to which the file belongs.</para>
246 <para> <literal>lmm_objects</literal></para>
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 {
256 } __attribute__((packed));</screen>
261 <para> <literal>l_object_id</literal></para>
264 <para>Holds the OST's object ID.</para>
269 <para> <literal>l_object_seq</literal></para>
272 <para>Holds the OST's object group.</para>
277 <para> <literal>l_ost_gen</literal></para>
280 <para>Holds the OST's index generation.</para>
285 <para> <literal>l_ost_idx</literal></para>
288 <para>Holds the OST's index in LOV.</para>
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>
302 <title>Errors</title>
303 <informaltable frame="all">
305 <colspec colname="c1" colwidth="50*"/>
306 <colspec colname="c2" colwidth="50*"/>
310 <para><emphasis role="bold">Errors</emphasis></para>
313 <para><emphasis role="bold">Description</emphasis></para>
320 <para> <literal>ENOMEM</literal></para>
323 <para>Failed to allocate memory</para>
328 <para> <literal>ENAMETOOLONG</literal></para>
331 <para>Path was too long</para>
336 <para> <literal>ENOENT</literal></para>
339 <para>Path does not point to a file or directory</para>
344 <para> <literal>ENOTTY</literal></para>
347 <para>Path does not point to a Lustre file system</para>
352 <para> <literal>EFAULT</literal></para>
355 <para>Memory region pointed by lum is not properly mapped</para>
363 <title>Examples</title>
365 #include <stdio.h>
366 #include <stdlib.h>
367 #include <errno.h>
368 #include <lustre/lustreapi.h>
370 static inline int maxint(int a, int b)
372 return a > b ? a : b;
374 static void *alloc_lum()
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));
383 int main(int argc, char** argv)
385 struct lov_user_md *lum_file = NULL;
389 fprintf(stderr, "Usage: %s <filename>\n", argv[0]);
392 lum_file = alloc_lum();
393 if (lum_file == NULL) {
397 rc = llapi_file_get_stripe(argv[1], lum_file);
402 /* stripe_size stripe_count */
403 printf("%d %d\n",
404 lum_file->lmm_stripe_size,
405 lum_file->lmm_stripe_count);
407 if (lum_file != NULL)
414 <section xml:id="dbdoclet.50438215_86607">
416 <literal>llapi_file_open</literal>
418 <para>The <literal>llapi_file_open</literal> command opens (or creates) a file or device on a
419 Lustre file system.</para>
421 <title>Synopsis</title>
422 <screen>#include <lustre/lustreapi.h>
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>);
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
436 <informaltable frame="all">
438 <colspec colname="c1" colwidth="50*"/>
439 <colspec colname="c2" colwidth="50*"/>
443 <para><emphasis role="bold">Option</emphasis></para>
446 <para><emphasis role="bold">Description</emphasis></para>
453 <para> <literal>flags</literal></para>
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>
461 <para> <literal>mode</literal></para>
464 <para>Specifies the permission bits to be used for a new file when <literal>O_CREAT</literal> is used.</para>
469 <para> <literal>stripe_size</literal></para>
472 <para>Specifies stripe size (in bytes). Should be multiple of 64 KB, not exceeding 4 GB.</para>
477 <para> <literal>stripe_offset</literal></para>
480 <para>Specifies an OST index from which the file should start. The default value is -1.</para>
485 <para> <literal>stripe_count</literal></para>
488 <para>Specifies the number of OSTs to stripe the file across. The default value is -1.</para>
493 <para> <literal>stripe_pattern</literal></para>
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
506 <title>Return Values</title>
507 <para><literal>llapi_file_open()</literal> and <literal>llapi_file_create()</literal> return:</para>
508 <para><literal>>=0</literal> On success, for <literal>llapi_file_open</literal> the return value is a file descriptor</para>
509 <para><literal><0</literal> On failure, the absolute value is an error code</para>
512 <title>Errors</title>
513 <informaltable frame="all">
515 <colspec colname="c1" colwidth="50*"/>
516 <colspec colname="c2" colwidth="50*"/>
520 <para><emphasis role="bold">Errors</emphasis></para>
523 <para><emphasis role="bold">Description</emphasis></para>
530 <para> <literal>EINVAL</literal></para>
533 <para><literal>stripe_size</literal> or <literal>stripe_offset</literal> or <literal>stripe_count</literal> or <literal>stripe_pattern</literal> is invalid.</para>
538 <para> <literal>EEXIST</literal></para>
541 <para>Striping information has already been set and cannot be altered; <literal>name</literal> already exists.</para>
546 <para> <literal>EALREADY</literal></para>
549 <para>Striping information has already been set and cannot be altered</para>
554 <para> <literal>ENOTTY</literal></para>
558 <literal>name</literal> may not point to a Lustre file system.</para>
566 <title>Example</title>
568 #include <stdio.h>
569 #include <lustre/lustreapi.h>
571 int main(int argc, char *argv[])
576 rc = llapi_file_create(argv[1], 1048576, 0, 2, LOV_PATTERN_RAID0);
578 fprintf(stderr, "file creation has failed, %s\n", strerror(-rc));
581 printf("%s with stripe size 1048576, striped across 2 OSTs,"
582 " has been created!\n", argv[1]);
588 <section xml:id="dbdoclet.50438215_12433">
590 <literal>llapi_quotactl</literal>
592 <para>Use <literal>llapi_quotact</literal>l to manipulate disk quotas on a Lustre file system.</para>
594 <title>Synopsis</title>
595 <screen>#include <lustre/lustreapi.h>
596 int llapi_quotactl(char" " *mnt," " struct if_quotactl" " *qctl)
603 struct obd_dqinfo qc_dqinfo;
604 struct obd_dqblk qc_dqblk;
606 struct obd_uuid obd_uuid;
609 __u64 dqb_bhardlimit;
610 __u64 dqb_bsoftlimit;
612 __u64 dqb_ihardlimit;
613 __u64 dqb_isoftlimit;
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">
635 <colspec colname="c1" colwidth="50*"/>
636 <colspec colname="c2" colwidth="50*"/>
640 <para><emphasis role="bold">Option</emphasis></para>
643 <para><emphasis role="bold">Description</emphasis></para>
650 <para> <literal>LUSTRE_Q_QUOTAON</literal></para>
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>
665 <para> <literal>LUSTRE_Q_QUOTAOFF</literal></para>
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>
673 <para> <literal>LUSTRE_Q_GETQUOTA</literal></para>
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>
681 <para> <literal>LUSTRE_Q_SETQUOTA</literal></para>
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>
689 <para> <literal>LUSTRE_Q_GETINFO</literal></para>
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
702 <para> <literal>LUSTRE_Q_SETINFO</literal></para>
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>
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>
724 <title>Errors</title>
725 <para><literal>llapi_quotactl</literal> errors are described below.</para>
726 <informaltable frame="all">
728 <colspec colname="c1" colwidth="50*"/>
729 <colspec colname="c2" colwidth="50*"/>
733 <para><emphasis role="bold">Errors</emphasis></para>
736 <para><emphasis role="bold">Description</emphasis></para>
743 <para> <literal>EFAULT</literal></para>
746 <para><emphasis>qctl</emphasis> is invalid.</para>
751 <para> <literal>ENOSYS</literal></para>
754 <para>Kernel or Lustre modules have not been compiled with the <literal>QUOTA</literal> option.</para>
759 <para> <literal>ENOMEM</literal></para>
762 <para>Insufficient memory to complete operation.</para>
767 <para> <literal>ENOTTY</literal></para>
770 <para> <emphasis>qc_cmd</emphasis> is invalid.</para>
775 <para> <literal>EBUSY</literal></para>
778 <para>Cannot process during quotacheck.</para>
783 <para> <literal>ENOENT</literal></para>
786 <para> <emphasis>uuid</emphasis> does not correspond to OBD or <emphasis>mnt</emphasis> does not exist.</para>
791 <para> <literal>EPERM</literal></para>
794 <para>The call is privileged and the caller is not the super user.</para>
799 <para> <literal>ESRCH</literal></para>
802 <para>No disk quota is found for the indicated user. Quotas have not been turned on for this file system.</para>
810 <section xml:id="dbdoclet.50438215_15718">
812 <literal>llapi_path2fid</literal>
814 <para>Use <literal>llapi_path2fid</literal> to get the FID from the pathname.</para>
816 <title>Synopsis</title>
817 <screen>#include <lustre/lustreapi.h>
819 int llapi_path2fid(const char *path, unsigned long long *seq, unsigned long *oid, unsigned long *ver)</screen>
822 <title>Description</title>
823 <para>The <literal>llapi_path2fid</literal> function returns the FID (sequence : object ID : version) for the pathname.</para>
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>
832 <section xml:id="dbdoclet.50438215_marker-1297700">
833 <title>Example Using the <literal>llapi</literal> Library</title>
834 <para>Use <literal>llapi_file_create</literal> to set Lustre software properties for a new file.
835 For a synopsis and description of <literal>llapi_file_create</literal> and examples of how to
836 use it, see <xref linkend="configurationfilesmoduleparameters"/>.</para>
837 <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>
838 <para><emphasis role="bold">A simple C program to demonstrate striping API - libtest.c</emphasis></para>
840 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
841 * vim:expandtab:shiftwidth=8:tabstop=8:
843 * lustredemo - a simple example of lustreapi functions
845 #include <stdio.h>
846 #include <fcntl.h>
847 #include <dirent.h>
848 #include <errno.h>
849 #include <stdlib.h>
850 #include <lustre/lustreapi.h>
851 #define MAX_OSTS 1024
852 #define LOV_EA_SIZE(lum, num) (sizeof(*lum) + num * sizeof(*lum->lmm_objects))
853 #define LOV_EA_MAX(lum) LOV_EA_SIZE(lum, MAX_OSTS)
856 * This program provides crude examples of using the lustreapi API functions
858 /* Change these definitions to suit */
860 #define TESTDIR "/tmp" /* Results directory */
861 #define TESTFILE "lustre_dummy" /* Name for the file we create/destroy */
862 #define FILESIZE 262144 /* Size of the file in words */
863 #define DUMWORD "DEADBEEF" /* Dummy word used to fill files */
864 #define MY_STRIPE_WIDTH 2 /* Set this to the number of OST required */
865 #define MY_LUSTRE_DIR "/mnt/lustre/ftest"
867 int close_file(int fd)
869 if (close(fd) < 0) {
870 fprintf(stderr, "File close failed: %d (%s)\n", errno, strerror(errno));
876 int write_file(int fd)
878 char *stng = DUMWORD;
881 for( cnt = 0; cnt < FILESIZE; cnt++) {
882 write(fd, stng, sizeof(stng));
886 /* Open a file, set a specific stripe count, size and starting OST
887 * Adjust the parameters to suit */
888 int open_stripe_file()
890 char *tfile = TESTFILE;
891 int stripe_size = 65536; /* System default is 4M */
892 int stripe_offset = -1; /* Start at default */
893 int stripe_count = MY_STRIPE_WIDTH; /*Single stripe for this demo*/
894 int stripe_pattern = 0; /* only RAID 0 at this time */
897 rc = llapi_file_create(tfile,
898 stripe_size,stripe_offset,stripe_count,stripe_pattern);
899 /* result code is inverted, we may return -EINVAL or an ioctl error.
900 * We borrow an error message from sanity.c
903 fprintf(stderr,"llapi_file_create failed: %d (%s) \n", rc, strerror(-rc));
906 /* llapi_file_create closes the file descriptor, we must re-open */
907 fd = open(tfile, O_CREAT | O_RDWR | O_LOV_DELAY_CREATE, 0644);
909 fprintf(stderr, "Can't open %s file: %d (%s)\n", tfile, errno, strerror(errno));
915 /* output a list of uuids for this file */
916 int get_my_uuids(int fd)
918 struct obd_uuid uuids[1024], *uuidp; /* Output var */
922 rc = llapi_lov_get_uuids(fd, uuids, &obdcount);
924 fprintf(stderr, "get uuids failed: %d (%s)\n",errno, strerror(errno));
926 printf("This file system has %d obds\n", obdcount);
927 for (i = 0, uuidp = uuids; i < obdcount; i++, uuidp++) {
928 printf("UUID %d is %s\n",i, uuidp->uuid);
933 /* Print out some LOV attributes. List our objects */
934 int get_file_info(char *path)
937 struct lov_user_md *lump;
941 lump = malloc(LOV_EA_MAX(lump));
946 rc = llapi_file_get_stripe(path, lump);
949 fprintf(stderr, "get_stripe failed: %d (%s)\n",errno, strerror(errno));
953 printf("Lov magic %u\n", lump->lmm_magic);
954 printf("Lov pattern %u\n", lump->lmm_pattern);
955 printf("Lov object id %llu\n", lump->lmm_object_id);
956 printf("Lov stripe size %u\n", lump->lmm_stripe_size);
957 printf("Lov stripe count %hu\n", lump->lmm_stripe_count);
958 printf("Lov stripe offset %u\n", lump->lmm_stripe_offset);
959 for (i = 0; i < lump->lmm_stripe_count; i++) {
960 printf("Object index %d Objid %llu\n", lump->lmm_objects[i].l_ost_idx, lump->lmm_objects[i].l_object_id);
968 /* Ping all OSTs that belong to this filesystem */
976 sprintf(osc_dir, "/proc/fs/lustre/osc");
977 dir = opendir(osc_dir);
979 printf("Can't open dir\n");
982 while((d = readdir(dir)) != NULL) {
983 if ( d->d_type == DT_DIR ) {
984 if (! strncmp(d->d_name, "OSC", 3)) {
985 printf("Pinging OSC %s ", d->d_name);
986 rc = llapi_ping("osc", d->d_name);
988 printf(" bad\n");
990 printf(" good\n");
1006 sprintf(filename, "%s/%s",MY_LUSTRE_DIR, TESTFILE);
1008 printf("Open a file with striping\n");
1009 file = open_stripe_file();
1010 if ( file < 0 ) {
1011 printf("Exiting\n");
1014 printf("Getting uuid list\n");
1015 rc = get_my_uuids(file);
1016 printf("Write to the file\n");
1017 rc = write_file(file);
1018 rc = close_file(file);
1019 printf("Listing LOV data\n");
1020 rc = get_file_info(filename);
1021 printf("Ping our OSTs\n");
1024 /* the results should match lfs getstripe */
1025 printf("Confirming our results with lfs getstripe\n");
1026 sprintf(sys_cmd, "/usr/bin/lfs getstripe %s/%s", MY_LUSTRE_DIR, TESTFILE);
1029 printf("All done\n");
1033 <para><emphasis role="bold">Makefile for sample application:</emphasis></para>
1035 gcc -g -O2 -Wall -o lustredemo libtest.c -llustreapi
1037 rm -f core lustredemo *.o
1040 rm -f /mnt/lustre/ftest/lustredemo
1041 rm -f /mnt/lustre/ftest/lustre_dummy
1042 cp lustredemo /mnt/lustre/ftest/
1044 <section remap="h5">
1045 <title>See Also</title>
1049 <xref linkend="dbdoclet.50438215_30970"/>
1054 <xref linkend="dbdoclet.50438215_50149"/>
1059 <xref linkend="dbdoclet.50438215_86607"/>
1064 <xref linkend="dbdoclet.50438215_12433"/>