4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
27 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
30 * Copyright (c) 2011, Whamcloud, Inc.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
36 * lustre/utils/mount_utils_ldiskfs.c
38 * Author: Nathan Rutman <nathan@clusterfs.com>
41 /* This source file is compiled into both mkfs.lustre and tunefs.lustre */
45 #endif /* HAVE_CONFIG_H */
57 #include <sys/types.h>
59 #include <sys/mount.h>
60 #include <sys/utsname.h>
68 /* libcfs.h is not really needed here, but on SLES10/PPC, fs.h includes idr.h
69 * which requires BITS_PER_LONG to be defined */
70 #include <libcfs/libcfs.h>
72 #include <linux/fs.h> /* for BLKGETSIZE64 */
74 #include <linux/version.h>
76 #include <lustre_disk.h>
77 #include <lustre_param.h>
78 #include <lnet/lnetctl.h>
79 #include <lustre_ver.h>
80 #include "mount_utils.h"
82 extern char *progname;
84 #define L_BLOCK_SIZE 4096
85 /* keep it less than LL_FID_NAMELEN */
86 #define DUMMY_FILE_NAME_LEN 25
87 #define EXT3_DIRENT_SIZE DUMMY_FILE_NAME_LEN
89 /* Write the server config files */
90 int write_local_files(struct mkfs_opts *mop)
92 char mntpt[] = "/tmp/mntXXXXXX";
99 /* Mount this device temporarily in order to write these files */
100 if (!mkdtemp(mntpt)) {
101 fprintf(stderr, "%s: Can't create temp mount point %s: %s\n",
102 progname, mntpt, strerror(errno));
106 dev = mop->mo_device;
107 if (mop->mo_flags & MO_IS_LOOP)
108 dev = mop->mo_loopdev;
110 ret = mount(dev, mntpt, MT_STR(&mop->mo_ldd), 0,
111 mop->mo_ldd.ldd_mount_opts);
113 fprintf(stderr, "%s: Unable to mount %s: %s\n",
114 progname, dev, strerror(errno));
116 if (errno == ENODEV) {
117 fprintf(stderr, "Is the %s module available?\n",
118 MT_STR(&mop->mo_ldd));
123 /* Set up initial directories */
124 sprintf(filepnm, "%s/%s", mntpt, MOUNT_CONFIGS_DIR);
125 ret = mkdir(filepnm, 0777);
126 if ((ret != 0) && (errno != EEXIST)) {
127 fprintf(stderr, "%s: Can't make configs dir %s (%s)\n",
128 progname, filepnm, strerror(errno));
130 } else if (errno == EEXIST) {
134 /* Save the persistent mount data into a file. Lustre must pre-read
135 this file to get the real mount options. */
136 vprint("Writing %s\n", MOUNT_DATA_FILE);
137 sprintf(filepnm, "%s/%s", mntpt, MOUNT_DATA_FILE);
138 filep = fopen(filepnm, "w");
140 fprintf(stderr, "%s: Unable to create %s file: %s\n",
141 progname, filepnm, strerror(errno));
144 num = fwrite(&mop->mo_ldd, sizeof(mop->mo_ldd), 1, filep);
145 if (num < 1 && ferror(filep)) {
146 fprintf(stderr, "%s: Unable to write to file (%s): %s\n",
147 progname, filepnm, strerror(errno));
159 int read_local_files(struct mkfs_opts *mop)
161 char tmpdir[] = "/tmp/dirXXXXXX";
167 int cmdsz = sizeof(cmd);
169 /* Make a temporary directory to hold Lustre data files. */
170 if (!mkdtemp(tmpdir)) {
171 fprintf(stderr, "%s: Can't create temporary directory %s: %s\n",
172 progname, tmpdir, strerror(errno));
176 dev = mop->mo_device;
178 /* TODO: it's worth observing the get_mountdata() function that is
179 in mount_utils.c for getting the mountdata out of the
182 /* Construct debugfs command line. */
183 snprintf(cmd, cmdsz, "%s -c -R 'dump /%s %s/mountdata' '%s'",
184 DEBUGFS, MOUNT_DATA_FILE, tmpdir, dev);
186 ret = run_command(cmd, cmdsz);
188 verrprint("%s: Unable to dump %s dir (%d)\n",
189 progname, MOUNT_CONFIGS_DIR, ret);
191 sprintf(filepnm, "%s/mountdata", tmpdir);
192 filep = fopen(filepnm, "r");
195 vprint("Reading %s\n", MOUNT_DATA_FILE);
196 num_read = fread(&mop->mo_ldd, sizeof(mop->mo_ldd), 1, filep);
197 if (num_read < 1 && ferror(filep)) {
198 fprintf(stderr, "%s: Unable to read from file %s: %s\n",
199 progname, filepnm, strerror(errno));
206 snprintf(cmd, cmdsz, "rm -rf %s", tmpdir);
207 run_command(cmd, cmdsz);
209 verrprint("Failed to read old data (%d)\n", ret);
214 /* Display the need for the latest e2fsprogs to be installed. make_backfs
215 * indicates if the caller is make_lustre_backfs() or not. */
216 void disp_old_e2fsprogs_msg(const char *feature, int make_backfs)
218 static int msg_displayed;
221 fprintf(stderr, "WARNING: %s does not support %s "
222 "feature.\n\n", E2FSPROGS, feature);
228 fprintf(stderr, "WARNING: The %s package currently installed on "
229 "your system does not support \"%s\" feature.\n",
231 #if !(HAVE_LDISKFSPROGS)
232 fprintf(stderr, "Please install the latest version of e2fsprogs from\n"
233 "http://downloads.whamcloud.com/public/e2fsprogs/latest/\n"
234 "to enable this feature.\n");
237 fprintf(stderr, "Feature will not be enabled until %s"
238 "is updated and '%s -O %s %%{device}' "
239 "is run.\n\n", E2FSPROGS, TUNE2FS, feature);
242 /* Check whether the file exists in the device */
243 static int file_in_dev(char *file_name, char *dev_name)
246 char debugfs_cmd[256];
247 unsigned int inode_num;
250 /* Construct debugfs command line. */
251 snprintf(debugfs_cmd, sizeof(debugfs_cmd),
252 "%s -c -R 'stat %s' '%s' 2>&1 | egrep '(Inode|unsupported)'",
253 DEBUGFS, file_name, dev_name);
255 fp = popen(debugfs_cmd, "r");
257 fprintf(stderr, "%s: %s\n", progname, strerror(errno));
261 if (fscanf(fp, "Inode: %u", &inode_num) == 1) { /* exist */
265 i = fread(debugfs_cmd, 1, sizeof(debugfs_cmd), fp);
268 fprintf(stderr, "%s", debugfs_cmd);
269 if (strstr(debugfs_cmd, "unsupported feature")) {
270 disp_old_e2fsprogs_msg("an unknown", 0);
279 /* Check whether the device has already been used with lustre */
280 int ldiskfs_is_lustre(char *dev, unsigned *mount_type)
284 ret = file_in_dev(MOUNT_DATA_FILE, dev);
286 /* in the -1 case, 'extents' means IS a lustre target */
287 *mount_type = LDD_MT_LDISKFS;
291 ret = file_in_dev(LAST_RCVD, dev);
293 *mount_type = LDD_MT_LDISKFS;
300 /* Check if a certain feature is supported by e2fsprogs.
301 * Firstly we try to use "debugfs supported_features" command to check if
302 * the feature is supported. If this fails we try to set this feature with
303 * mke2fs to check for its support. */
304 static int is_e2fsprogs_feature_supp(const char *feature)
306 static char supp_features[4096] = "";
309 char imgname[] = "/tmp/test-img-XXXXXX";
313 if (supp_features[0] == '\0') {
314 snprintf(cmd, sizeof(cmd), "%s -c -R supported_features 2>&1",
317 /* Using popen() instead of run_command() since debugfs does
318 * not return proper error code if command is not supported */
319 fp = popen(cmd, "r");
321 fprintf(stderr, "%s: %s\n", progname, strerror(errno));
324 ret = fread(supp_features, 1, sizeof(supp_features), fp);
327 if (ret > 0 && strstr(supp_features,
328 strncmp(feature, "-O ", 3) ? feature : feature+3))
331 if ((fd = mkstemp(imgname)) < 0)
336 snprintf(cmd, sizeof(cmd), "%s -F %s %s 100 >/dev/null 2>&1",
337 MKE2FS, feature, imgname);
338 /* run_command() displays the output of mke2fs when it fails for
339 * some feature, so use system() directly */
348 * append_unique: append @key or @key=@val pair to @buf only if @key does not
350 * @buf: buffer to hold @key or @key=@val
351 * @prefix: prefix string before @key
353 * @val: value string if it's a @key=@val pair
355 static void append_unique(char *buf, char *prefix, char *key, char *val,
364 anchor = end = strstr(buf, key);
365 /* try to find exact match string in @buf */
366 while (end && *end != '\0' && *end != ',' && *end != ' ' && *end != '=')
369 if (anchor == NULL || strlen(key) != len ||
370 strncmp(anchor, key, len) != 0) {
372 strscat(buf, prefix, maxbuflen);
374 strscat(buf, key, maxbuflen);
376 strscat(buf, "=", maxbuflen);
377 strscat(buf, val, maxbuflen);
382 static void enable_default_ext4_features(struct mkfs_opts *mop, char *anchor,
383 size_t maxbuflen, int user_spec)
385 if (IS_OST(&mop->mo_ldd)) {
386 append_unique(anchor, user_spec ? "," : " -O ",
387 "extents", NULL, sizeof(mop->mo_mkfsopts));
388 append_unique(anchor, ",", "uninit_bg", NULL, maxbuflen);
389 } else if (IS_MDT(&mop->mo_ldd)) {
390 append_unique(anchor, user_spec ? "," : " -O ",
391 "dirdata", NULL, maxbuflen);
392 append_unique(anchor, ",", "uninit_bg", NULL, maxbuflen);
393 append_unique(anchor, ",", "^extents", NULL, maxbuflen);
395 append_unique(anchor, user_spec ? "," : " -O ",
396 "uninit_bg", NULL, maxbuflen);
399 /* Multiple mount protection enabled only if failover node specified */
400 if (mop->mo_flags & MO_FAILOVER) {
401 if (is_e2fsprogs_feature_supp("-O mmp") == 0)
402 append_unique(anchor, ",", "mmp", NULL, maxbuflen);
404 disp_old_e2fsprogs_msg("mmp", 1);
407 /* Allow more than 65000 subdirectories */
408 if (is_e2fsprogs_feature_supp("-O dir_nlink") == 0)
409 append_unique(anchor, ",", "dir_nlink", NULL, maxbuflen);
411 /* The following options are only valid for ext4-based ldiskfs.
412 * If --backfstype=ext3 is specified, do not enable them. */
413 if (mop->mo_ldd.ldd_mount_type == LDD_MT_EXT3)
416 /* Allow files larger than 2TB. Also needs LU-16, but not harmful. */
417 if (is_e2fsprogs_feature_supp("-O huge_file") == 0)
418 append_unique(anchor, ",", "huge_file", NULL, maxbuflen);
420 /* Enable large block addresses if the LUN is over 2^32 blocks. */
421 if (mop->mo_device_sz / (L_BLOCK_SIZE >> 10) >= 0x100002000ULL &&
422 is_e2fsprogs_feature_supp("-O 64bit") == 0)
423 append_unique(anchor, ",", "64bit", NULL, maxbuflen);
425 /* Cluster inode/block bitmaps and inode table for more efficient IO.
426 * Align the flex groups on a 1MB boundary for better performance. */
427 /* This -O feature needs to go last, since it adds the "-G" option. */
428 if (is_e2fsprogs_feature_supp("-O flex_bg") == 0) {
431 append_unique(anchor, ",", "flex_bg", NULL, maxbuflen);
433 if (IS_OST(&mop->mo_ldd)) {
434 snprintf(tmp_buf, sizeof(tmp_buf), " -G %u",
435 (1 << 20) / L_BLOCK_SIZE);
436 strscat(anchor, tmp_buf, maxbuflen);
439 /* Don't add any more "-O" options here, see last comment above */
443 * moveopts_to_end: find the option string, move remaining strings to
444 * where option string starts, and append the option
446 * @start: where the option string starts before the move
447 * RETURN: where the option string starts after the move
449 static char *moveopts_to_end(char *start)
454 /* skip whitespace before options */
459 /* find end of option characters */
460 while (*end != ' ' && *end != '\0')
464 strncpy(save, start, end - start);
465 save[end - start] = '\0';
467 /* move remaining options up front */
469 memmove(start, end, strlen(end));
470 *(start + strlen(end)) = '\0';
472 /* append the specified options */
473 if (*(start + strlen(start) - 1) != ' ')
475 idx = start + strlen(start);
481 /* Build fs according to type */
482 int make_lustre_backfs(struct mkfs_opts *mop)
484 __u64 device_sz = mop->mo_device_sz, block_count = 0;
485 char mkfs_cmd[PATH_MAX];
489 int ret = 0, ext_opts = 0;
492 if (!(mop->mo_flags & MO_IS_LOOP)) {
493 mop->mo_device_sz = get_device_size(mop->mo_device);
495 if (mop->mo_device_sz == 0)
498 /* Compare to real size */
499 if (device_sz == 0 || device_sz > mop->mo_device_sz)
500 device_sz = mop->mo_device_sz;
502 mop->mo_device_sz = device_sz;
505 if (mop->mo_device_sz != 0) {
506 if (mop->mo_device_sz < 8096){
507 fprintf(stderr, "%s: size of filesystem must be larger "
508 "than 8MB, but is set to %lldKB\n",
509 progname, (long long)mop->mo_device_sz);
512 block_count = mop->mo_device_sz / (L_BLOCK_SIZE >> 10);
513 /* If the LUN size is just over 2^32 blocks, limit the
514 * filesystem size to 2^32-1 blocks to avoid problems with
515 * ldiskfs/mkfs not handling this size. Bug 22906 */
516 if (block_count > 0xffffffffULL && block_count < 0x100002000ULL)
517 block_count = 0xffffffffULL;
520 if ((mop->mo_ldd.ldd_mount_type == LDD_MT_EXT3) ||
521 (mop->mo_ldd.ldd_mount_type == LDD_MT_LDISKFS) ||
522 (mop->mo_ldd.ldd_mount_type == LDD_MT_LDISKFS2)) {
525 /* Journal size in MB */
526 if (strstr(mop->mo_mkfsopts, "-J") == NULL) {
527 /* Choose our own default journal size */
528 long journal_sz = 0, max_sz;
529 if (device_sz > 1024 * 1024) /* 1GB */
530 journal_sz = (device_sz / 102400) * 4;
531 /* cap journal size at 1GB */
532 if (journal_sz > 1024L)
535 max_sz = (102400 * L_BLOCK_SIZE) >> 20; /* 400MB */
536 if (journal_sz > max_sz)
539 sprintf(buf, " -J size=%ld", journal_sz);
540 strscat(mop->mo_mkfsopts, buf,
541 sizeof(mop->mo_mkfsopts));
545 /* Inode size (for extended attributes). The LOV EA size is
546 * 32 (EA hdr) + 32 (lov_mds_md) + stripes * 24 (lov_ost_data),
547 * and we want some margin above that for ACLs, other EAs... */
548 if (strstr(mop->mo_mkfsopts, "-I") == NULL) {
549 if (IS_MDT(&mop->mo_ldd)) {
550 if (mop->mo_stripe_count > 72)
551 inode_size = 512; /* bz 7241 */
552 /* see also "-i" below for EA blocks */
553 else if (mop->mo_stripe_count > 32)
555 else if (mop->mo_stripe_count > 10)
559 } else if (IS_OST(&mop->mo_ldd)) {
560 /* We store MDS FID and OST objid in EA on OST
561 * we need to make inode bigger as well. */
565 if (inode_size > 0) {
566 sprintf(buf, " -I %ld", inode_size);
567 strscat(mop->mo_mkfsopts, buf,
568 sizeof(mop->mo_mkfsopts));
572 /* Bytes_per_inode: disk size / num inodes */
573 if (strstr(mop->mo_mkfsopts, "-i") == NULL &&
574 strstr(mop->mo_mkfsopts, "-N") == NULL) {
575 long bytes_per_inode = 0;
577 /* Allocate more inodes on MDT devices. There is
578 * no data stored on the MDT, and very little extra
579 * metadata beyond the inode. It could go down as
580 * low as 1024 bytes, but this is conservative.
581 * Account for external EA blocks for wide striping. */
582 if (IS_MDT(&mop->mo_ldd)) {
583 bytes_per_inode = inode_size + 1536;
585 if (mop->mo_stripe_count > 72) {
586 int extra = mop->mo_stripe_count * 24;
587 extra = ((extra - 1) | 4095) + 1;
588 bytes_per_inode += extra;
592 /* Allocate fewer inodes on large OST devices. Most
593 * filesystems can be much more aggressive than even
594 * this, but it is impossible to know in advance. */
595 if (IS_OST(&mop->mo_ldd)) {
596 /* OST > 16TB assume average file size 1MB */
597 if (device_sz > (16ULL << 30))
598 bytes_per_inode = 1024 * 1024;
599 /* OST > 4TB assume average file size 512kB */
600 else if (device_sz > (4ULL << 30))
601 bytes_per_inode = 512 * 1024;
602 /* OST > 1TB assume average file size 256kB */
603 else if (device_sz > (1ULL << 30))
604 bytes_per_inode = 256 * 1024;
605 /* OST > 10GB assume average file size 64kB,
606 * plus a bit so that inodes will fit into a
607 * 256x flex_bg without overflowing */
608 else if (device_sz > (10ULL << 20))
609 bytes_per_inode = 69905;
612 if (bytes_per_inode > 0) {
613 sprintf(buf, " -i %ld", bytes_per_inode);
614 strscat(mop->mo_mkfsopts, buf,
615 sizeof(mop->mo_mkfsopts));
620 strscat(mop->mo_mkfsopts, " -q",
621 sizeof(mop->mo_mkfsopts));
624 /* start handle -O mkfs options */
625 if ((start = strstr(mop->mo_mkfsopts, "-O")) != NULL) {
626 if (strstr(start + 2, "-O") != NULL) {
628 "%s: don't specify multiple -O options\n",
632 start = moveopts_to_end(start);
633 maxbuflen = sizeof(mop->mo_mkfsopts) -
634 (start - mop->mo_mkfsopts) - strlen(start);
635 enable_default_ext4_features(mop, start, maxbuflen, 1);
637 start = mop->mo_mkfsopts + strlen(mop->mo_mkfsopts),
638 maxbuflen = sizeof(mop->mo_mkfsopts) -
639 strlen(mop->mo_mkfsopts);
640 enable_default_ext4_features(mop, start, maxbuflen, 0);
642 /* end handle -O mkfs options */
644 /* start handle -E mkfs options */
645 if ((start = strstr(mop->mo_mkfsopts, "-E")) != NULL) {
646 if (strstr(start + 2, "-E") != NULL) {
648 "%s: don't specify multiple -E options\n",
652 start = moveopts_to_end(start);
653 maxbuflen = sizeof(mop->mo_mkfsopts) -
654 (start - mop->mo_mkfsopts) - strlen(start);
657 start = mop->mo_mkfsopts + strlen(mop->mo_mkfsopts);
658 maxbuflen = sizeof(mop->mo_mkfsopts) -
659 strlen(mop->mo_mkfsopts);
662 /* In order to align the filesystem metadata on 1MB boundaries,
663 * give a resize value that will reserve a power-of-two group
664 * descriptor blocks, but leave one block for the superblock.
665 * Only useful for filesystems with < 2^32 blocks due to resize
667 if (IS_OST(&mop->mo_ldd) && mop->mo_device_sz > 100 * 1024 &&
668 mop->mo_device_sz * 1024 / L_BLOCK_SIZE <= 0xffffffffULL) {
669 unsigned group_blocks = L_BLOCK_SIZE * 8;
670 unsigned desc_per_block = L_BLOCK_SIZE / 32;
671 unsigned resize_blks;
673 resize_blks = (1ULL<<32) - desc_per_block*group_blocks;
674 snprintf(buf, sizeof(buf), "%u", resize_blks);
675 append_unique(start, ext_opts ? "," : " -E ",
676 "resize", buf, maxbuflen);
680 /* Avoid zeroing out the full journal - speeds up mkfs */
681 if (is_e2fsprogs_feature_supp("-E lazy_journal_init") == 0)
682 append_unique(start, ext_opts ? "," : " -E ",
683 "lazy_journal_init", NULL, maxbuflen);
684 /* end handle -E mkfs options */
686 /* Allow reformat of full devices (as opposed to
687 partitions.) We already checked for mounted dev. */
688 strscat(mop->mo_mkfsopts, " -F", sizeof(mop->mo_mkfsopts));
690 snprintf(mkfs_cmd, sizeof(mkfs_cmd),
691 "%s -j -b %d -L %s ", MKE2FS, L_BLOCK_SIZE,
692 mop->mo_ldd.ldd_svname);
694 fprintf(stderr,"%s: unsupported fs type: %d (%s)\n",
695 progname, mop->mo_ldd.ldd_mount_type,
696 MT_STR(&mop->mo_ldd));
700 /* For loop device format the dev, not the filename */
701 dev = mop->mo_device;
702 if (mop->mo_flags & MO_IS_LOOP)
703 dev = mop->mo_loopdev;
705 vprint("formatting backing filesystem %s on %s\n",
706 MT_STR(&mop->mo_ldd), dev);
707 vprint("\ttarget name %s\n", mop->mo_ldd.ldd_svname);
708 vprint("\t4k blocks "LPU64"\n", block_count);
709 vprint("\toptions %s\n", mop->mo_mkfsopts);
711 /* mkfs_cmd's trailing space is important! */
712 strscat(mkfs_cmd, mop->mo_mkfsopts, sizeof(mkfs_cmd));
713 strscat(mkfs_cmd, " ", sizeof(mkfs_cmd));
714 strscat(mkfs_cmd, dev, sizeof(mkfs_cmd));
715 if (block_count != 0) {
716 sprintf(buf, " "LPU64, block_count);
717 strscat(mkfs_cmd, buf, sizeof(mkfs_cmd));
720 vprint("mkfs_cmd = %s\n", mkfs_cmd);
721 ret = run_command(mkfs_cmd, sizeof(mkfs_cmd));
724 fprintf(stderr, "Unable to build fs %s (%d)\n", dev, ret);
729 int ldiskfs_prepare_lustre(struct mkfs_opts *mop,
730 char *default_mountopts, int default_len,
731 char *always_mountopts, int always_len)
733 struct lustre_disk_data *ldd = &mop->mo_ldd;
736 /* Set MO_IS_LOOP to indicate a loopback device is needed */
737 ret = is_block(mop->mo_device);
740 } else if (ret == 0) {
741 mop->mo_flags |= MO_IS_LOOP;
744 strscat(default_mountopts, ",errors=remount-ro", default_len);
745 if (IS_MDT(ldd) || IS_MGS(ldd))
746 strscat(always_mountopts, ",user_xattr", always_len);
751 /* return canonicalized absolute pathname, even if the target file does not
752 * exist, unlike realpath */
753 static char *absolute_path(char *devname)
755 char buf[PATH_MAX + 1];
759 path = malloc(PATH_MAX + 1);
763 if (devname[0] != '/') {
764 if (getcwd(buf, sizeof(buf) - 1) == NULL)
767 strcat(buf, devname);
769 strcpy(buf, devname);
771 /* truncate filename before calling realpath */
772 ptr = strrchr(buf, '/');
778 if (path != realpath(buf, path)) {
782 /* add the filename back */
784 strcat(path, ptr + 1);
788 /* Determine if a device is a block device (as opposed to a file) */
789 int is_block(char* devname)
795 devpath = absolute_path(devname);
796 if (devpath == NULL) {
797 fprintf(stderr, "%s: failed to resolve path to %s\n",
802 ret = access(devname, F_OK);
804 if (strncmp(devpath, "/dev/", 5) == 0) {
805 /* nobody sane wants to create a loopback file under
806 * /dev. Let's just report the device doesn't exist */
807 fprintf(stderr, "%s: %s apparently does not exist\n",
815 ret = stat(devpath, &st);
817 fprintf(stderr, "%s: cannot stat %s\n", progname, devpath);
820 ret = S_ISBLK(st.st_mode);