Revision - 3ae7065 - dm: retain table limits when swapping to new table with no devices - origin: https://github.com/torvalds/linux

visit type:

https://github.com/torvalds/linux

16 September 2024, 20:19:31 UTC

Revision 3ae706561637331aa578e52bb89ecbba5edcb7a9 authored by Mike Snitzer on 26 September 2012, 22:45:45 UTC, committed by Alasdair G Kergon on 26 September 2012, 22:45:45 UTC

dm: retain table limits when swapping to new table with no devices

Add a safety net that will re-use the DM device's existing limits in the
event that DM device has a temporary table that doesn't have any
component devices.  This is to reduce the chance that requests not
respecting the hardware limits will reach the device.

DM recalculates queue limits based only on devices which currently exist
in the table.  This creates a problem in the event all devices are
temporarily removed such as all paths being lost in multipath.  DM will
reset the limits to the maximum permissible, which can then assemble
requests which exceed the limits of the paths when the paths are
restored.  The request will fail the blk_rq_check_limits() test when
sent to a path with lower limits, and will be retried without end by
multipath.  This became a much bigger issue after v3.6 commit fe86cdcef
("block: do not artificially constrain max_sectors for stacking
drivers").

Reported-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 parent c3c4555

Files
Changes

Permalinks

Tip revision: 3ae706561637331aa578e52bb89ecbba5edcb7a9 authored by Mike Snitzer on 26 September 2012, 22:45:45 UTC
dm: retain table limits when swapping to new table with no devices

Tip revision: 3ae7065

File	Mode	Size
Documentation
arch
block
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.gitignore	-rw-r--r--	1014 bytes
.mailmap	-rw-r--r--	4.4 KB
COPYING	-rw-r--r--	18.3 KB
CREDITS	-rw-r--r--	92.7 KB
Kbuild	-rw-r--r--	2.5 KB
Kconfig	-rw-r--r--	252 bytes
MAINTAINERS	-rw-r--r--	210.8 KB
Makefile	-rw-r--r--	46.1 KB
README	-rw-r--r--	17.3 KB
REPORTING-BUGS	-rw-r--r--	3.3 KB

Showing with 0 additions and 0 deletions (0 / 0 diffs computed)

Computing file changes ...

https://github.com/torvalds/linux

dm: retain table limits when swapping to new table with no devices

README