04 Jun, 2014
2 commits
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There is no need for code other than DM core to use dm_set_device_limits
so remove its EXPORT_SYMBOL_GPL. Also, cleanup a couple whitespace nits.Signed-off-by: Mike Snitzer
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The function dm_accept_partial_bio allows the target to specify how many
sectors of the current bio it will process. If the target only wants to
accept part of the bio, it calls dm_accept_partial_bio and the DM core
sends the rest of the data in next bio.Signed-off-by: Mikulas Patocka
Signed-off-by: Mike Snitzer
28 Mar, 2014
2 commits
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Introduce dm_table_run_md_queue_async() to run the request_queue of the
mapped_device associated with a request-based DM table.Also add dm_md_get_queue() wrapper to extract the request_queue from a
mapped_device.Signed-off-by: Mike Snitzer
Signed-off-by: Hannes Reinecke
Reviewed-by: Jun'ichi Nomura -
Remove dm_get_mapinfo() because no target uses it. Targets can allocate
per-bio data using ti->per_bio_data_size, this is much more flexible
than union map_info.Leave union map_info only for the request-based multipath target's use.
Also delete the unused "unsigned long long ll" field of union map_info.Signed-off-by: Mikulas Patocka
Signed-off-by: Mike Snitzer
20 Sep, 2013
1 commit
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Workaround the SCSI layer's problematic WRITE SAME heuristics by
disabling WRITE SAME in the DM multipath device's queue_limits if an
underlying device disabled it.The WRITE SAME heuristics, with both the original commit 5db44863b6eb
("[SCSI] sd: Implement support for WRITE SAME") and the updated commit
66c28f971 ("[SCSI] sd: Update WRITE SAME heuristics"), default to enabling
WRITE SAME(10) even without successfully determining it is supported.
After the first failed WRITE SAME the SCSI layer will disable WRITE SAME
for the device (by setting sdkp->device->no_write_same which results in
'max_write_same_sectors' in device's queue_limits to be set to 0).When a device is stacked ontop of such a SCSI device any changes to that
SCSI device's queue_limits do not automatically propagate up the stack.
As such, a DM multipath device will not have its WRITE SAME support
disabled. This causes the block layer to continue to issue WRITE SAME
requests to the mpath device which causes paths to fail and (if mpath IO
isn't configured to queue when no paths are available) it will result in
actual IO errors to the upper layers.This fix doesn't help configurations that have additional devices
stacked ontop of the mpath device (e.g. LVM created linear DM devices
ontop). A proper fix that restacks all the queue_limits from the bottom
of the device stack up will need to be explored if SCSI will continue to
use this model of optimistically allowing op codes and then disabling
them after they fail for the first time.Before this patch:
EXT4-fs (dm-6): mounted filesystem with ordered data mode. Opts: (null)
device-mapper: multipath: XXX snitm debugging: got -EREMOTEIO (-121)
device-mapper: multipath: XXX snitm debugging: failing WRITE SAME IO with error=-121
end_request: critical target error, dev dm-6, sector 528
dm-6: WRITE SAME failed. Manually zeroing.
device-mapper: multipath: Failing path 8:112.
end_request: I/O error, dev dm-6, sector 4616
dm-6: WRITE SAME failed. Manually zeroing.
end_request: I/O error, dev dm-6, sector 4616
end_request: I/O error, dev dm-6, sector 5640
end_request: I/O error, dev dm-6, sector 6664
end_request: I/O error, dev dm-6, sector 7688
end_request: I/O error, dev dm-6, sector 524288
Buffer I/O error on device dm-6, logical block 65536
lost page write due to I/O error on dm-6
JBD2: Error -5 detected when updating journal superblock for dm-6-8.
end_request: I/O error, dev dm-6, sector 524296
Aborting journal on device dm-6-8.
end_request: I/O error, dev dm-6, sector 524288
Buffer I/O error on device dm-6, logical block 65536
lost page write due to I/O error on dm-6
JBD2: Error -5 detected when updating journal superblock for dm-6-8.# cat /sys/block/sdh/queue/write_same_max_bytes
0
# cat /sys/block/dm-6/queue/write_same_max_bytes
33553920After this patch:
EXT4-fs (dm-6): mounted filesystem with ordered data mode. Opts: (null)
device-mapper: multipath: XXX snitm debugging: got -EREMOTEIO (-121)
device-mapper: multipath: XXX snitm debugging: WRITE SAME I/O failed with error=-121
end_request: critical target error, dev dm-6, sector 528
dm-6: WRITE SAME failed. Manually zeroing.# cat /sys/block/sdh/queue/write_same_max_bytes
0
# cat /sys/block/dm-6/queue/write_same_max_bytes
0It should be noted that WRITE SAME support wasn't enabled in DM
multipath until v3.10.Signed-off-by: Mike Snitzer
Cc: Martin K. Petersen
Cc: Hannes Reinecke
Cc: stable@vger.kernel.org # 3.10+
06 Sep, 2013
1 commit
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Support the collection of I/O statistics on user-defined regions of
a DM device. If no regions are defined no statistics are collected so
there isn't any performance impact. Only bio-based DM devices are
currently supported.Each user-defined region specifies a starting sector, length and step.
Individual statistics will be collected for each step-sized area within
the range specified.The I/O statistics counters for each step-sized area of a region are
in the same format as /sys/block/*/stat or /proc/diskstats but extra
counters (12 and 13) are provided: total time spent reading and
writing in milliseconds. All these counters may be accessed by sending
the @stats_print message to the appropriate DM device via dmsetup.The creation of DM statistics will allocate memory via kmalloc or
fallback to using vmalloc space. At most, 1/4 of the overall system
memory may be allocated by DM statistics. The admin can see how much
memory is used by reading
/sys/module/dm_mod/parameters/stats_current_allocated_bytesSee Documentation/device-mapper/statistics.txt for more details.
Signed-off-by: Mikulas Patocka
Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
11 Jul, 2013
1 commit
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This patch removes "io_lock" and "map_lock" in struct mapped_device and
"holders" in struct dm_table and replaces these mechanisms with
sleepable-rcu.Previously, the code would call "dm_get_live_table" and "dm_table_put" to
get and release table. Now, the code is changed to call "dm_get_live_table"
and "dm_put_live_table". dm_get_live_table locks sleepable-rcu and
dm_put_live_table unlocks it.dm_get_live_table_fast/dm_put_live_table_fast can be used instead of
dm_get_live_table/dm_put_live_table. These *_fast functions use
non-sleepable RCU, so the caller must not block between them.If the code changes active or inactive dm table, it must call
dm_sync_table before destroying the old table.Signed-off-by: Mikulas Patocka
Signed-off-by: Jun'ichi Nomura
Signed-off-by: Alasdair G Kergon
10 May, 2013
1 commit
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Document iterate_devices in device-mapper.h.
Signed-off-by: Alasdair G Kergon
02 Mar, 2013
3 commits
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Add a num_write_bios function to struct target.
If an instance of a target sets this, it will be queried before the
target's mapping function is called on a write bio, and the response
controls the number of copies of the write bio that the target will
receive.This provides a convenient way for a target to send the same data to
more than one device. The new cache target uses this in writethrough
mode, to send the data both to the cache and the backing device.Signed-off-by: Alasdair G Kergon
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Use 'bio' in the name of variables and functions that deal with
bios rather than 'request' to avoid confusion with the normal
block layer use of 'request'.No functional changes.
Signed-off-by: Alasdair G Kergon
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Avoid returning a truncated table or status string instead of setting
the DM_BUFFER_FULL_FLAG when the last target of a table fills the
buffer.When processing a table or status request, the function retrieve_status
calls ti->type->status. If ti->type->status returns non-zero,
retrieve_status assumes that the buffer overflowed and sets
DM_BUFFER_FULL_FLAG.However, targets don't return non-zero values from their status method
on overflow. Most targets returns always zero.If a buffer overflow happens in a target that is not the last in the
table, it gets noticed during the next iteration of the loop in
retrieve_status; but if a buffer overflow happens in the last target, it
goes unnoticed and erroneously truncated data is returned.In the current code, the targets behave in the following way:
* dm-crypt returns -ENOMEM if there is not enough space to store the
key, but it returns 0 on all other overflows.
* dm-thin returns errors from the status method if a disk error happened.
This is incorrect because retrieve_status doesn't check the error
code, it assumes that all non-zero values mean buffer overflow.
* all the other targets always return 0.This patch changes the ti->type->status function to return void (because
most targets don't use the return code). Overflow is detected in
retrieve_status: if the status method fills up the remaining space
completely, it is assumed that buffer overflow happened.Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon
22 Dec, 2012
4 commits
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This patch removes map_info from bio-based device mapper targets.
map_info is still used for request-based targets.Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon -
This patch moves target_request_nr from map_info to dm_target_io and
makes it accessible with dm_bio_get_target_request_nr.This patch is a preparation for the next patch that removes map_info.
Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon -
Introduce a field per_bio_data_size in struct dm_target.
Targets can set this field in the constructor. If a target sets this
field to a non-zero value, "per_bio_data_size" bytes of auxiliary data
are allocated for each bio submitted to the target. These data can be
used for any purpose by the target and help us improve performance by
removing some per-target mempools.Per-bio data is accessed with dm_per_bio_data. The
argument data_size must be the same as the value per_bio_data_size in
dm_target.If the target has a pointer to per_bio_data, it can get a pointer to
the bio with dm_bio_from_per_bio_data() function (data_size must be the
same as the value passed to dm_per_bio_data).Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon -
Allow targets to opt in to WRITE SAME support by setting
'num_write_same_requests' in the dm_target structure.A dm device will only advertise WRITE SAME support if all its
targets and all its underlying devices support it.Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
27 Jul, 2012
6 commits
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Commit outstanding metadata before returning the status for a dm thin
pool so that the numbers reported are as up-to-date as possible.The commit is not performed if the device is suspended or if
the DM_NOFLUSH_FLAG is supplied by userspace and passed to the target
through a new 'status_flags' parameter in the target's dm_status_fn.The userspace dmsetup tool will support the --noflush flag with the
'dmsetup status' and 'dmsetup wait' commands from version 1.02.76
onwards.Tested-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon -
Use boolean bit fields for flags in struct dm_target.
Signed-off-by: Alasdair G Kergon
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Allow targets to override the 'supports flush' calculation.
Set 'flush_supported' if a target needs to receive flushes regardless of
whether or not its underlying devices have support.Signed-off-by: Joe Thornber
Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon -
This patch introduces a new variable split_discard_requests. It can be
set by targets so that discard requests are split on max_io_len
boundaries.When split_discard_requests is not set, discard requests are only split on
boundaries between targets, as was the case before this patch.Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon -
Remove the restriction that limits a target's specified maximum incoming
I/O size to be a power of 2.Rename this setting from 'split_io' to the less-ambiguous 'max_io_len'.
Change it from sector_t to uint32_t, which is plenty big enough, and
introduce a wrapper function dm_set_target_max_io_len() to set it.
Use sector_div() to process it now that it is not necessarily a power of 2.Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon -
Remove unused dm_flush_fn .flush target method from header.
This was left-over from the FLUSH/FUA conversion and is no longer used.
Signed-off-by: Joe Thornber
Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
01 Nov, 2011
4 commits
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Introduce DM_TARGET_IMMUTABLE to indicate that the target type cannot be mixed
with any other target type, and once loaded into a device, it cannot be
replaced with a table containing a different type.The thin provisioning pool device will use this.
Signed-off-by: Alasdair G Kergon
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Add a target feature flag DM_TARGET_ALWAYS_WRITEABLE to indicate that a target
does not support read-only mode.The initial implementation of the thin provisioning target uses this.
Signed-off-by: Alasdair G Kergon
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Introduce the concept of a singleton table which contains exactly one target.
If a target type sets the DM_TARGET_SINGLETON feature bit device-mapper
will ensure that any table that includes that target contains no others.The thin provisioning pool target uses this.
Signed-off-by: Alasdair G Kergon
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printk_ratelimit() shares global ratelimiting state with all
other subsystems, so its usage is discouraged. Instead,
define and use dm's local state.Signed-off-by: Namhyung Kim
Signed-off-by: Alasdair G Kergon
26 Sep, 2011
1 commit
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If optional discard support in dm-crypt is enabled, discards requests
bypass the crypt queue and blocks of the underlying device are discarded.
For the read path, discarded blocks are handled the same as normal
ciphertext blocks, thus decrypted.So if the underlying device announces discarded regions return zeroes,
dm-crypt must disable this flag because after decryption there is just
random noise instead of zeroes.Signed-off-by: Milan Broz
Signed-off-by: Alasdair G Kergon
02 Aug, 2011
1 commit
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Move multipath target argument parsing code into dm-table so other
targets can share it.Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
29 May, 2011
1 commit
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Permit a target to support discards regardless of whether or not all its
underlying devices do.Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
18 Apr, 2011
1 commit
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Now that unplugging is done differently, the unplug_fn callback is
never called, so it can be completely discarded.Signed-off-by: NeilBrown
10 Mar, 2011
1 commit
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Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().Signed-off-by: Jens Axboe
14 Jan, 2011
2 commits
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Add per-target unplug callback support.
Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown
Signed-off-by: Jonathan Brassow
Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon -
DM currently implements congestion checking by checking on congestion
in each component device. For raid456 we need to also check if the
stripe cache is congested.Add per-target congestion checker callback support.
Extending the target_callbacks structure with additional callback
functions allows for establishing multiple callbacks per-target (a
callback is also needed for unplug).Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown
Signed-off-by: Jonathan Brassow
Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
12 Aug, 2010
3 commits
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Split max_io_len_target_boundary out of max_io_len so that the discard
support can make use of it without duplicating max_io_len code.Avoiding max_io_len's split_io logic enables DM's discard support to
submit the entire discard request to a target. But discards must still
be split on target boundaries.Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon -
Allow discards to be passed through to linear mappings if at least one
underlying device supports it. Discards will be forwarded only to
devices that support them.A target that supports discards should set num_discard_requests to
indicate how many times each discard request must be submitted to it.Verify table's underlying devices support discards prior to setting the
associated DM device as capable of discards (via QUEUE_FLAG_DISCARD).Signed-off-by: Mike Snitzer
Signed-off-by: Mikulas Patocka
Reviewed-by: Joe Thornber
Signed-off-by: Alasdair G Kergon -
'target_request_nr' is a more generic name that reflects the fact that
it will be used for both flush and discard support.Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
06 Mar, 2010
1 commit
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Remove unused parameters(start and len) of dm_get_device()
and fix the callers.Signed-off-by: Nikanth Karthikesan
Signed-off-by: Alasdair G Kergon
11 Dec, 2009
4 commits
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This patch adds the exported dm_suspended() function so that targets
can check whether or not they are suspended.Signed-off-by: Kiyoshi Ueda
Signed-off-by: Jun'ichi Nomura
Cc: Mike Anderson
Signed-off-by: Alasdair G Kergon -
This patch renames dm_suspended() to dm_suspended_md() and
keeps it internal to dm.
No functional change.Signed-off-by: Kiyoshi Ueda
Signed-off-by: Jun'ichi Nomura
Cc: Mike Anderson
Signed-off-by: Alasdair G Kergon -
When swapping a new table into place, retain the old table until
its replacement is in place.An old check for an empty table is removed because this is enforced
in populate_table().__unbind() becomes redundant when followed by __bind().
Signed-off-by: Alasdair G Kergon
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Rename dm_get_table to dm_get_live_table.
Signed-off-by: Alasdair G Kergon
