s390/dasd: add copy pair swap capability

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In case of errors or misbehaviour of the primary device a controlled
failover to one of the configured secondary devices needs to be
performed.

The swap processing stops I/O on the primary device, all requests are
re-queued to the blocklayer queue, the entries in the copy relation are
swapped and finally the link to the blockdevice is moved from primary to
secondary dasd device.
After this, the secondary becomes the new primary device and I/O is
restarted on that device.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-5-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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This commit is contained in:

Stefan Haberland 2022-09-20 21:26:13 +02:00 • committed by Jens Axboe

parent a91ff09d39

commit 413862caad

4 changed files with 117 additions and 1 deletions

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3

drivers/s390/block/dasd.c

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1

drivers/s390/block/dasd_devmap.c

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94

drivers/s390/block/dasd_eckd.c

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20

drivers/s390/block/dasd_int.h

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