linux.git/drivers/md/raid0.c, branch v6.13

md/raid0: Atomic write support

2024-11-19T17:30:02+00:00

Set BLK_FEAT_ATOMIC_WRITES_STACKED to enable atomic writes. All other
stacked device request queue limits should automatically be set properly.
With regards to atomic write max bytes limit, this will be set at
hw_max_sectors and this is limited by the stripe width, which we want.

Reviewed-by: Yu Kuai 
Signed-off-by: John Garry 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20241118105018.1870052-4-john.g.garry@oracle.com
Signed-off-by: Jens Axboe

md/raid0: Handle bio_split() errors

2024-11-11T15:35:46+00:00

Add proper bio_split() error handling. For any error, set bi_status, end
the bio, and return.

Reviewed-by: Yu Kuai 
Reviewed-by: Hannes Reinecke 
Signed-off-by: John Garry 
Link: https://lore.kernel.org/r/20241111112150.3756529-5-john.g.garry@oracle.com
Signed-off-by: Jens Axboe

md: set md-specific flags for all queue limits

2024-06-26T15:37:35+00:00

The md driver wants to enforce a number of flags for all devices, even
when not inheriting them from the underlying devices.  To make sure these
flags survive the queue_limits_set calls that md uses to update the
queue limits without deriving them form the previous limits add a new
md_init_stacking_limits helper that calls blk_set_stacking_limits and sets
these flags.

Fixes: 1122c0c1cc71 ("block: move cache control settings out of queue->flags")
Reported-by: kernel test robot 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20240626142637.300624-2-hch@lst.de
Signed-off-by: Jens Axboe

block: move integrity information into queue_limits

2024-06-14T16:20:07+00:00

Move the integrity information into the queue limits so that it can be
set atomically with other queue limits, and that the sysfs changes to
the read_verify and write_generate flags are properly synchronized.
This also allows to provide a more useful helper to stack the integrity
fields, although it still is separate from the main stacking function
as not all stackable devices want to inherit the integrity settings.
Even with that it greatly simplifies the code in md and dm.

Note that the integrity field is moved as-is into the queue limits.
While there are good arguments for removing the separate blk_integrity
structure, this would cause a lot of churn and might better be done at a
later time if desired.  However the integrity field in the queue_limits
structure is now unconditional so that various ifdefs can be avoided or
replaced with IS_ENABLED().  Given that tiny size of it that seems like
a worthwhile trade off.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20240613084839.1044015-13-hch@lst.de
Signed-off-by: Jens Axboe

md/raid0: don't free conf on raid0_run failure

2024-06-14T16:20:06+00:00

The core md code calls the ->free method which already frees conf.

Fixes: 0c031fd37f69 ("md: Move alloc/free acct bioset in to personality")
Signed-off-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Yu Kuai 
Link: https://lore.kernel.org/r/20240613084839.1044015-3-hch@lst.de
Signed-off-by: Jens Axboe

md: remove mddev->queue

2024-03-06T16:59:53+00:00

Just use the request_queue from the gendisk pointer in the relatively
few places that sill need it.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-11-hch@lst.de

md/raid0: use the atomic queue limit update APIs

2024-03-06T16:59:53+00:00

Build the queue limits outside the queue and apply them using
queue_limits_set.  To make the code more obvious also split the queue
limits handling into a separate helper function.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-6-hch@lst.de

md: add a mddev_is_dm helper

2024-03-06T16:59:53+00:00

Add a helper to check for a DM-mapped MD device instead of using
the obfuscated ->gendisk or ->queue NULL checks.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-4-hch@lst.de

md: add a mddev_trace_remap helper

2024-03-06T16:59:52+00:00

Add a helper to trace bio remapping that hides some argument
dereferences and the check for a DM-mapped MD device.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-2-hch@lst.de

md: raid0: account for split bio in iostat accounting

2023-08-18T04:11:31+00:00

When a bio is split by md raid0, the newly created bio will not be tracked
by md for I/O accounting. Only the portion of I/O still assigned to the
original bio which was reduced by the split will be accounted for. This
results in md iostat data sometimes showing I/O values far below the actual
amount of data being sent through md.

md_account_bio() needs to be called for all bio generated by the bio split.

A simple example of the issue was generated using a raid0 device on partitions
to the same device. Since all raid0 I/O then goes to one device, it makes it
easy to see a gap between the md device and its sd storage. Reading an lvm
device on top of the md device, the iostat output (some 0 columns and extra
devices removed to make the data more compact) was:

Device             tps    kB_read/s    kB_wrtn/s    kB_dscd/s    kB_read
md2               0.00         0.00         0.00         0.00          0
sde               0.00         0.00         0.00         0.00          0
md2            1364.00    411496.00         0.00         0.00     411496
sde            1734.00    646144.00         0.00         0.00     646144
md2            1699.00    510680.00         0.00         0.00     510680
sde            2155.00    802784.00         0.00         0.00     802784
md2             803.00    241480.00         0.00         0.00     241480
sde            1016.00    377888.00         0.00         0.00     377888
md2               0.00         0.00         0.00         0.00          0
sde               0.00         0.00         0.00         0.00          0

I/O was generated doing large direct I/O reads (12M) with dd to a linear
lvm volume on top of the 4 leg raid0 device.

The md2 reads were showing as roughly 2/3 of the reads to the sde device
containing all of md2's raid partitions. The sum of reads to sde was
1826816 kB, which was the expected amount as it was the amount read by
dd. With the patch, the total reads from md will match the reads from
sde and be consistent with the amount of I/O generated.

Fixes: 10764815ff47 ("md: add io accounting for raid0 and raid5")
Signed-off-by: David Jeffery 
Tested-by: Laurence Oberman 
Reviewed-by: Laurence Oberman 
Reviewed-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230816181433.13289-1-djeffery@redhat.com