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blkid: improve RAIDs and tiny devices probing 

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2010-04-22 21:52:31 +02:00
parent c81e70087c
commit cba1f9757a
1 changed files with 20 additions and 47 deletions
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67
misc-utils/blkid.c
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@ -419,7 +419,7 @@ static int lowprobe_device(blkid_probe pr, const char *devname, char *show[],
{
const char *data;
const char *name;
int nvals = 0, n, num = 1, has_pt = 0;
int nvals = 0, n, num = 1;
size_t len;
int fd;
int rc = 0;
@ -436,62 +436,35 @@ static int lowprobe_device(blkid_probe pr, const char *devname, char *show[],
if (fstat(fd, &st))
goto done;
/*
* partitions probing
*/
blkid_probe_enable_superblocks(pr, 0); /* enabled by default ;-( */
blkid_probe_enable_partitions(pr, 1);
/* This is for PART_ENTRY_{UUID,NAME,TYPE,...} values and it will
* open() whole-disk device.
*/
blkid_probe_set_partitions_flags(pr, BLKID_PARTS_ENTRY_DETAILS);
rc = blkid_do_fullprobe(pr);
blkid_probe_enable_partitions(pr, 0);
if (rc < 0)
goto done; /* -1 = error, 1 = nothing, 0 = succes */
if (blkid_probe_lookup_value(pr, "PTTYPE", NULL, NULL) == 0)
/* partition table detected */
has_pt = 1;
/*
* filesystems/raids probing
*
* Q: Why do we try to probe for FS/RAID on device with partiton table?
*
* A: For some devices the kernel creates partitions because it is too
* dumb to find out, that the device contains a RAID signature or
* other metadata that signifies, that this device should not be
* handled.
*
* Many RAID signatures are at the end of the device, or at least
* still allow that the volume contains a partition table at the
* beginning of the device, which the kernel will find. Udev needs
* to look at the disk, if there are such RAID signatures, and then
* it needs to handle it, and in many cases just kill all the
* wrongly kernel-created partitions.
*
* -- Kay Sievers
* http://thread.gmane.org/gmane.linux.utilities.util-linux-ng/2888/focus=2890
*
* This all is unncecessary for very small devices (<= 1.44MiB).
*/
if (has_pt == 0 || S_ISCHR(st.st_mode) ||
blkid_probe_get_size(pr) > 1024 * 1440) {
if (!S_ISCHR(st.st_mode) && blkid_probe_get_size(pr) <= 1024 * 1440) {
/*
* filesystems/RAIDs probing
* check if the small disk is partitioned, if yes then
* don't probe for filesystems.
*/
blkid_probe_enable_superblocks(pr, 1);
blkid_probe_enable_superblocks(pr, 0);
rc = blkid_do_safeprobe(pr);
rc = blkid_do_fullprobe(pr);
if (rc < 0)
goto done;
goto done; /* -1 = error, 1 = nothing, 0 = succes */
if (blkid_probe_lookup_value(pr, "PTTYPE", NULL, NULL) == 0)
/* partition table detected */
goto print_vals;
/* small whole-disk is unpartitioned, probe for filesystems only */
blkid_probe_enable_partitions(pr, 0);
}
blkid_probe_enable_superblocks(pr, 1);
rc = blkid_do_safeprobe(pr);
if (rc < 0)
goto done;
print_vals:
nvals = blkid_probe_numof_values(pr);
if (nvals && !first && output & OUTPUT_UDEV_LIST)