s390/dasd: fix string length handling

Building dasd_eckd.o with latest clang reveals this bug:

CC drivers/s390/block/dasd_eckd.o
drivers/s390/block/dasd_eckd.c:1082:3: warning: 'snpr

s390/dasd: fix string length handling

Building dasd_eckd.o with latest clang reveals this bug:

CC drivers/s390/block/dasd_eckd.o
drivers/s390/block/dasd_eckd.c:1082:3: warning: 'snprintf' will always be truncated;
specified size is 1, but format string expands to at least 11 [-Wfortify-source]
1082 | snprintf(print_uid, sizeof(*print_uid),
| ^
drivers/s390/block/dasd_eckd.c:1087:3: warning: 'snprintf' will always be truncated;
specified size is 1, but format string expands to at least 10 [-Wfortify-source]
1087 | snprintf(print_uid, sizeof(*print_uid),
| ^

Fix this by moving and using the existing UID_STRLEN for the arrays
that are being written to. Also rename UID_STRLEN to DASD_UID_STRLEN
to clarify its scope.

Fixes: 23596961b437 ("s390/dasd: split up dasd_eckd_read_conf")
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com> # build
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://github.com/ClangBuiltLinux/linux/issues/1923
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230828153142.2843753-2-hca@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390: include linux/io.h instead of asm/io.h

Include linux/io.h instead of asm/io.h everywhere. linux/io.h includes
asm/io.h, so this shouldn't cause any problems. Instead this might help for
some r

s390: include linux/io.h instead of asm/io.h

Include linux/io.h instead of asm/io.h everywhere. linux/io.h includes
asm/io.h, so this shouldn't cause any problems. Instead this might help for
some randconfig build errors which were reported due to some undefined io
related functions.

Also move the changed include so it stays grouped together with other
includes from the same directory.

For ctcm_mpc.c also remove not needed comments (actually questions).

Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

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s390/dasd: fix command reject error on ESE devices

Formatting a thin-provisioned (ESE) device that is part of a PPRC copy
relation might fail with the following error:

dasd-eckd 0.0.f500: An error

s390/dasd: fix command reject error on ESE devices

Formatting a thin-provisioned (ESE) device that is part of a PPRC copy
relation might fail with the following error:

dasd-eckd 0.0.f500: An error occurred in the DASD device driver, reason=09
[...]
24 Byte: 0 MSG 4, no MSGb to SYSOP

During format of an ESE disk the Release Allocated Space command is used.
A bit in the payload of the command is set that is not allowed to be set
for devices in a copy relation. This bit is set to allow the partial
release of an extent.

Check for the existence of a copy relation before setting the respective
bit.

Fixes: 91dc4a197569 ("s390/dasd: Add new ioctl to release space")
Cc: stable@kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20230519102340.3854819-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: add aq_timeouts autoquiesce trigger

Add a sysfs attribute aq_timeouts that controls after how many
timeouts a autoquiesce event might be triggered.

The default value is 32768 which is th

s390/dasd: add aq_timeouts autoquiesce trigger

Add a sysfs attribute aq_timeouts that controls after how many
timeouts a autoquiesce event might be triggered.

The default value is 32768 which is the maximum number of retries
for the DASD device driver DASD_RETRIES_MAX. This means that the
timeout trigger will never happen.

The default value for DASD retries is 255.
Setting the value to below 255 will trigger the timeout autoquiesce
event before an IO error is generated.

Also add the check for the configured amount of timeouts and trigger
an autoquiesce event if exceeded.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Link: https://lore.kernel.org/r/20230405142017.2446986-6-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: Fix potential memleak in dasd_eckd_init()

`dasd_reserve_req` is allocated before `dasd_vol_info_req`, and it
also needs to be freed before the error returns, just like the other
cases in

s390/dasd: Fix potential memleak in dasd_eckd_init()

`dasd_reserve_req` is allocated before `dasd_vol_info_req`, and it
also needs to be freed before the error returns, just like the other
cases in this function.

Fixes: 9e12e54c7a8f ("s390/dasd: Handle out-of-space constraint")
Signed-off-by: Qiheng Lin <linqiheng@huawei.com>
Link: https://lore.kernel.org/r/20221208133809.16796-1-linqiheng@huawei.com
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20230210000253.1644903-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: sort out physical vs virtual pointers usage

This does not fix a real bug, since virtual addresses
are currently indentical to physical ones.

Signed-off-by: Alexander Gordeev <agordeev@li

s390/dasd: sort out physical vs virtual pointers usage

This does not fix a real bug, since virtual addresses
are currently indentical to physical ones.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20230210000253.1644903-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: fix no record found for raw_track_access

For DASD devices in raw_track_access mode only full track images are
read and written.
For this purpose it is not necessary to do search operation

s390/dasd: fix no record found for raw_track_access

For DASD devices in raw_track_access mode only full track images are
read and written.
For this purpose it is not necessary to do search operation in the
locate record extended function. The documentation even states that
this might fail if the searched record is not found on a track.

Currently the driver sets a value of 1 in the search field for the first
record after record zero. This is the default for disks not in
raw_track_access mode but record 1 might be missing on a completely
empty track.

There has not been any problem with this on IBM storage servers but it
might lead to errors with DASD devices on other vendors storage servers.

Fix this by setting the search field to 0. Record zero is always available
even on a completely empty track.

Fixes: e4dbb0f2b5dd ("[S390] dasd: Add support for raw ECKD access.")
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20221123160719.3002694-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: increase printing of debug data payload

32 byte are to less for important data from prefix or
other commands.
Print up to 128 byte data. This is enough for the largest
CCW data we have.

s390/dasd: increase printing of debug data payload

32 byte are to less for important data from prefix or
other commands.
Print up to 128 byte data. This is enough for the largest
CCW data we have.

Since printk can only print up to 1024 byte at once, print the
different parts of the CCW dumps separately.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20221123160719.3002694-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: use blk_mq_alloc_disk

As far as I can tell there is no need for the staged setup in
dasd, so allocate the tagset and the disk with the queue in
dasd_gendisk_alloc.

Signed-off-by: Christo

s390/dasd: use blk_mq_alloc_disk

As far as I can tell there is no need for the staged setup in
dasd, so allocate the tagset and the disk with the queue in
dasd_gendisk_alloc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220928143945.1687114-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: add device ping attribute

Add a function to check if a device is accessible.
This makes mostly sense for copy pair secondary devices but it will work
for all devices.

The sysfs attribute

s390/dasd: add device ping attribute

Add a function to check if a device is accessible.
This makes mostly sense for copy pair secondary devices but it will work
for all devices.

The sysfs attribute ping is a write only attribute and will issue a NOP
CCW to the device.
In case of success it will return zero. If the device is not accessible
it will return an error code.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-8-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: add copy pair swap capability

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 pro

s390/dasd: add copy pair swap capability

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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s390/dasd: add copy pair setup

A copy relation that is configured on the storage server side needs to be
enabled separately in the device driver. A sysfs interface is created
that allows userspace t

s390/dasd: add copy pair setup

A copy relation that is configured on the storage server side needs to be
enabled separately in the device driver. A sysfs interface is created
that allows userspace tooling to control such setup.

The following sysfs entries are added to store and read copy relation
information:

copy_pair
- Add/Delete a copy pair relation to the DASD device driver
- Query all previously added copy pair relations
copy_role
- Query the copy pair role of the device

To add a copy pair to the DASD device driver it has to be specified
through the sysfs attribute copy_pair. Only one secondary device can be
specified at a time together with the primary device. Both, secondary
and primary can be used equally to define the copy pair.
The secondary devices have to be offline when adding the copy relation.
The primary device needs to be specified first followed by the comma
separated secondary device.
Read from the copy_pair attribute to get the current setup and write
"clear" to the attribute to delete any existing setup.

Example:
$ echo 0.0.9700,0.0.9740 > /sys/bus/ccw/devices/0.0.9700/copy_pair
$ cat /sys/bus/ccw/devices/0.0.9700/copy_pair
0.0.9700,0.0.9740

During device online processing the required data will be read from the
storage server and the information will be compared to the setup
requested through the copy_pair attribute. The registration of the
primary and secondary device will be handled accordingly.
A blockdevice is only allocated for copy relation primary devices.

To query the copy role of a device read from the copy_role sysfs
attribute. Possible values are primary, secondary, and none.

Example:
$ cat /sys/bus/ccw/devices/0.0.9700/copy_role
primary

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: add query PPRC function

Add function to query the Peer-to-Peer-Remote-Copy (PPRC) state of a
device by reading the related structure through a read subsystem data call.

Signed-off-by: St

s390/dasd: add query PPRC function

Add function to query the Peer-to-Peer-Remote-Copy (PPRC) state of a
device by reading the related structure through a read subsystem data call.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

s390/dasd: put block allocation in separate function

Put block allocation into a separate function to put some copy pair logic
in it in a later patch.

Signed-off-by: Stefan Haberland <sth@linux.ibm

s390/dasd: put block allocation in separate function

Put block allocation into a separate function to put some copy pair logic
in it in a later patch.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: Establish DMA alignment

linux-next commit bf8d08532bc1 ("iomap: add support for dma aligned
direct-io") changes the alignment requirement to come from the block
device rather than the blo

s390/dasd: Establish DMA alignment

linux-next commit bf8d08532bc1 ("iomap: add support for dma aligned
direct-io") changes the alignment requirement to come from the block
device rather than the block size, and the default alignment
requirement is 512-byte boundaries. Since DASD I/O has page
alignments for IDAW/TIDAW requests, let's override this value to
restore the expected behavior.

Make this change for both ECKD and DIAG disciplines, as they both
would fall into this category. Leave FBA alone, since it is always
comprised of 512-byte blocks.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220804213926.3361574-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: Use kzalloc instead of kmalloc/memset

Use kzalloc rather than duplicating its implementation, which
makes code simple and easy to understand.

Signed-off-by: Haowen Bai <baihaowen@meizu.c

s390/dasd: Use kzalloc instead of kmalloc/memset

Use kzalloc rather than duplicating its implementation, which
makes code simple and easy to understand.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-6-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: Fix read for ESE with blksize < 4k

When reading unformatted tracks on ESE devices, the corresponding memory
areas are simply set to zero for each segment. This is done incorrectly
for blo

s390/dasd: Fix read for ESE with blksize < 4k

When reading unformatted tracks on ESE devices, the corresponding memory
areas are simply set to zero for each segment. This is done incorrectly
for blocksizes < 4096.

There are two problems. First, the increment of dst is done using the
counter of the loop (off), which is increased by blksize every
iteration. This leads to a much bigger increment for dst as actually
intended. Second, the increment of dst is done before the memory area
is set to 0, skipping a significant amount of bytes of memory.

This leads to illegal overwriting of memory and ultimately to a kernel
panic.

This is not a problem with 4k blocksize because
blk_queue_max_segment_size is set to PAGE_SIZE, always resulting in a
single iteration for the inner segment loop (bv.bv_len == blksize). The
incorrectly used 'off' value to increment dst is 0 and the correct
memory area is used.

In order to fix this for blksize < 4k, increment dst correctly using the
blksize and only do it at the end of the loop.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: prevent double format of tracks for ESE devices

For ESE devices we get an error for write operations on an unformatted
track. Afterwards the track will be formatted and the IO operation
r

s390/dasd: prevent double format of tracks for ESE devices

For ESE devices we get an error for write operations on an unformatted
track. Afterwards the track will be formatted and the IO operation
restarted.
When using alias devices a track might be accessed by multiple requests
simultaneously and there is a race window that a track gets formatted
twice resulting in data loss.

Prevent this by remembering the amount of formatted tracks when starting
a request and comparing this number before actually formatting a track
on the fly. If the number has changed there is a chance that the current
track was finally formatted in between. As a result do not format the
track and restart the current IO to check.

The number of formatted tracks does not match the overall number of
formatted tracks on the device and it might wrap around but this is no
problem. It is only needed to recognize that a track has been formatted at
all in between.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: fix data corruption for ESE devices

For ESE devices we get an error when accessing an unformatted track.
The handling of this error will return zero data for read requests and
format the

s390/dasd: fix data corruption for ESE devices

For ESE devices we get an error when accessing an unformatted track.
The handling of this error will return zero data for read requests and
format the track on demand before writing to it. To do this the code needs
to distinguish between read and write requests. This is done with data from
the blocklayer request. A pointer to the blocklayer request is stored in
the CQR.

If there is an error on the device an ERP request is built to do error
recovery. While the ERP request is mostly a copy of the original CQR the
pointer to the blocklayer request is not copied to not accidentally pass
it back to the blocklayer without cleanup.

This leads to the error that during ESE handling after an ERP request was
built it is not possible to determine the IO direction. This leads to the
formatting of a track for read requests which might in turn lead to data
corruption.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: fix missing path conf_data after failed allocation

dasd_eckd_path_available_action() does a memory allocation to store
the per path configuration data permanently.
In the unlikely case th

s390/dasd: fix missing path conf_data after failed allocation

dasd_eckd_path_available_action() does a memory allocation to store
the per path configuration data permanently.
In the unlikely case that this allocation fails there is no conf_data
stored for the corresponding path.

This is OK since this is not necessary for an operational path but some
features like control unit initiated reconfiguration (CUIR) do not work.

To fix this add the path to the 'to be verified pathmask' again and
schedule the handler again.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20211020115124.1735254-7-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: summarize dasd configuration data in a separate structure

Summarize the dasd configuration data in a separate structure so that
functions that need temporary config data do not need to al

s390/dasd: summarize dasd configuration data in a separate structure

Summarize the dasd configuration data in a separate structure so that
functions that need temporary config data do not need to allocate the
whole eckd_private structure.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20211020115124.1735254-6-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: move dasd_eckd_read_fc_security

dasd_eckd_read_conf is called multiple times during device setup but the
fc_security feature needs to be read only once. So move it into the calling
functi

s390/dasd: move dasd_eckd_read_fc_security

dasd_eckd_read_conf is called multiple times during device setup but the
fc_security feature needs to be read only once. So move it into the calling
function.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20211020115124.1735254-5-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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s390/dasd: split up dasd_eckd_read_conf

Move the cabling check out of dasd_eckd_read_conf and split it up into
separate functions to improve readability and re-use functions.

Signed-off-by: Stefan

s390/dasd: split up dasd_eckd_read_conf

Move the cabling check out of dasd_eckd_read_conf and split it up into
separate functions to improve readability and re-use functions.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20211020115124.1735254-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

s390/dasd: Fix read for ESE with blksize < 4k

commit cd68c48ea15c85f1577a442dc4c285e112ff1b37 upstream.

When reading unformatted tracks on ESE devices, the corresponding memory
areas are simply set

s390/dasd: Fix read for ESE with blksize < 4k

commit cd68c48ea15c85f1577a442dc4c285e112ff1b37 upstream.

When reading unformatted tracks on ESE devices, the corresponding memory
areas are simply set to zero for each segment. This is done incorrectly
for blocksizes < 4096.

There are two problems. First, the increment of dst is done using the
counter of the loop (off), which is increased by blksize every
iteration. This leads to a much bigger increment for dst as actually
intended. Second, the increment of dst is done before the memory area
is set to 0, skipping a significant amount of bytes of memory.

This leads to illegal overwriting of memory and ultimately to a kernel
panic.

This is not a problem with 4k blocksize because
blk_queue_max_segment_size is set to PAGE_SIZE, always resulting in a
single iteration for the inner segment loop (bv.bv_len == blksize). The
incorrectly used 'off' value to increment dst is 0 and the correct
memory area is used.

In order to fix this for blksize < 4k, increment dst correctly using the
blksize and only do it at the end of the loop.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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s390/dasd: prevent double format of tracks for ESE devices

commit 71f3871657370dbbaf942a1c758f64e49a36c70f upstream.

For ESE devices we get an error for write operations on an unformatted
track. Af

s390/dasd: prevent double format of tracks for ESE devices

commit 71f3871657370dbbaf942a1c758f64e49a36c70f upstream.

For ESE devices we get an error for write operations on an unformatted
track. Afterwards the track will be formatted and the IO operation
restarted.
When using alias devices a track might be accessed by multiple requests
simultaneously and there is a race window that a track gets formatted
twice resulting in data loss.

Prevent this by remembering the amount of formatted tracks when starting
a request and comparing this number before actually formatting a track
on the fly. If the number has changed there is a chance that the current
track was finally formatted in between. As a result do not format the
track and restart the current IO to check.

The number of formatted tracks does not match the overall number of
formatted tracks on the device and it might wrap around but this is no
problem. It is only needed to recognize that a track has been formatted at
all in between.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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