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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
Makefile 
# SPDX-License-Identifier: GPL-2.0
#
# Makefile for the linux kernel.
#

ccflags-y := -fno-function-sections -fno-data-sections

obj-y                          := main.o version.o mounts.o
ifneq ($(CONFIG_BLK_DEV_INITRD),y)
obj-y                          += noinitramfs.o
else
obj-$(CONFIG_BLK_DEV_INITRD)   += initramfs.o
endif
obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o

obj-y                          += init_task.o

mounts-y			:= do_mounts.o
mounts-$(CONFIG_BLK_DEV_RAM)	+= do_mounts_rd.o
mounts-$(CONFIG_BLK_DEV_INITRD)	+= do_mounts_initrd.o

# dependencies on generated files need to be listed explicitly
$(obj)/version.o: include/generated/compile.h

# compile.h changes depending on hostname, generation number, etc,
# so we regenerate it always.
# mkcompile_h will make sure to only update the
# actual file if its content has changed.

       chk_compile.h = :
 quiet_chk_compile.h = echo '  CHK     $@'
silent_chk_compile.h = :
include/generated/compile.h: FORCE
	@$($(quiet)chk_compile.h)
	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@	\
	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)"	\
	"$(CONFIG_PREEMPT_RT)" $(CONFIG_CC_VERSION_TEXT) "$(LD)"
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