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Revision 809b1e4945774c9ec5619a8f4e2189b7b3833c0c authored by Hannes Reinecke on 21 January 2021, 17:50:56 UTC, committed by Mike Snitzer on 21 January 2021, 20:06:45 UTC 
dm: avoid filesystem lookup in dm_get_dev_t()
 
This reverts commit
644bda6f3460 ("dm table: fall back to getting device using name_to_dev_t()")

dm_get_dev_t() is just used to convert an arbitrary 'path' string
into a dev_t. It doesn't presume that the device is present; that
check will be done later, as the only caller is dm_get_device(),
which does a dm_get_table_device() later on, which will properly
open the device.

So if the path string already _is_ in major:minor representation
we can convert it directly, avoiding a recursion into the filesystem
to lookup the block device.

This avoids a hang in multipath_message() when the filesystem is
inaccessible.

Fixes: 644bda6f3460 ("dm table: fall back to getting device using name_to_dev_t()")
Cc: stable@vger.kernel.org
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1 parent 004b8ae
Raw File
bounds.c 
// SPDX-License-Identifier: GPL-2.0
/*
 * Generate definitions needed by the preprocessor.
 * This code generates raw asm output which is post-processed
 * to extract and format the required data.
 */

#define __GENERATING_BOUNDS_H
/* Include headers that define the enum constants of interest */
#include <linux/page-flags.h>
#include <linux/mmzone.h>
#include <linux/kbuild.h>
#include <linux/log2.h>
#include <linux/spinlock_types.h>

int main(void)
{
	/* The enum constants to put into include/generated/bounds.h */
	DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS);
	DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES);
#ifdef CONFIG_SMP
	DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS));
#endif
	DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
	/* End of constants */

	return 0;
}
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