- 27 7月, 2012 1 次提交
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由 Alasdair G Kergon 提交于
Reduce the slab size used for the dm_thin_endio_hook mempool. Allocation has been seen to fail on machines with smaller amounts of memory due to fragmentation. lvm: page allocation failure. order:5, mode:0xd0 device-mapper: table: 253:38: thin-pool: Error creating pool's endio_hook mempool Cc: stable@vger.kernel.org Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 20 7月, 2012 1 次提交
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由 Mikulas Patocka 提交于
When process_discard receives a partial discard that doesn't cover a full block, it sends this discard down to that block. Unfortunately, the block can be shared and the discard would corrupt the other snapshots sharing this block. This patch detects block sharing and ends the discard with success when sending it to the shared block. The above change means that if the device supports discard it can't be guaranteed that a discard request zeroes data. Therefore, we set ti->discard_zeroes_data_unsupported. Thin target discard support with this bug arrived in commit 104655fd (dm thin: support discards). Signed-off-by: NMikulas Patocka <mpatocka@redhat.com> Cc: stable@kernel.org Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 03 7月, 2012 1 次提交
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由 Joe Thornber 提交于
Userland sometimes sees a corrupt metadata block if metadata is changing rapidly when a metadata snapshot is reserved for userland, To make the problem go away, commit before we take the metadata snapshot (which is a sensible thing to do anyway). The checksums mean userland spots this corruption immediately so there's no risk of acting on incorrect data. No corruption exists from the kernel's point of view, and thin_check passes after pool shutdown. I believe this is to do with shared blocks at the first level of the {device, mapping} btree. Prior to the metadata-snap support no sharing at this level was possible, so this patch is only required after commit cc8394d8 ("dm thin: provide userspace access to pool metadata"). Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 03 6月, 2012 2 次提交
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由 Joe Thornber 提交于
This patch implements two new messages that can be sent to the thin pool target allowing it to take a snapshot of the _metadata_. This, read-only snapshot can be accessed by userland, concurrently with the live target. Only one metadata snapshot can be held at a time. The pool's status line will give the block location for the current msnap. Since version 0.1.5 of the userland thin provisioning tools, the thin_dump program displays the msnap as follows: thin_dump -m <msnap root> <metadata dev> Available here: https://github.com/jthornber/thin-provisioning-tools Now that userland can access the metadata we can do various things that have traditionally been kernel side tasks: i) Incremental backups. By using metadata snapshots we can work out what blocks have changed over time. Combined with data snapshots we can ensure the data doesn't change while we back it up. A short proof of concept script can be found here: https://github.com/jthornber/thinp-test-suite/blob/master/incremental_backup_example.rb ii) Migration of thin devices from one pool to another. iii) Merging snapshots back into an external origin. iv) Asyncronous replication. Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Use dedicated caches prefixed with a "dm_" name rather than relying on kmalloc mempools backed by generic slab caches so the memory usage of thin provisioning (and any leaks) can be accounted for independently. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 19 5月, 2012 1 次提交
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由 Mike Snitzer 提交于
When the thin pool target clears the discard_passdown parameter internally, it incorrectly changes the table line reported to userspace. This breaks dumb string comparisons on these table lines in generic userspace device-mapper library code and leads to tables being reloaded repeatedly when nothing is actually meant to be changing. This patch corrects this by no longer changing the table line when discard passdown was disabled. We can still tell when discard passdown is overridden by looking for the message "Discard unsupported by data device (sdX): Disabling discard passdown." This automatic detection is also moved from the 'load' to the 'resume' so that it is re-evaluated should the properties of underlying devices change. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Acked-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 12 5月, 2012 3 次提交
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由 Alasdair G Kergon 提交于
Remove duplicate copy of string "device-mapper" (DM_NAME) from MODULE_DESCRIPTION. Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Fix two places in commit 104655fd ("dm thin: support discards") that didn't use pool->lock to protect against concurrent changes to the prepared_discards list. Without this fix, thin_endio() can race with process_discard(), leading to concurrent list_add()s that result in the processes locking up with an error like the following: WARNING: at lib/list_debug.c:32 __list_add+0x8f/0xa0() ... list_add corruption. next->prev should be prev (ffff880323b96140), but was ffff8801d2c48440. (next=ffff8801d2c485c0). ... Pid: 17205, comm: kworker/u:1 Tainted: G W O 3.4.0-rc3.snitm+ #1 Call Trace: [<ffffffff8103ca1f>] warn_slowpath_common+0x7f/0xc0 [<ffffffff8103cb16>] warn_slowpath_fmt+0x46/0x50 [<ffffffffa04f6ce6>] ? bio_detain+0xc6/0x210 [dm_thin_pool] [<ffffffff8124ff3f>] __list_add+0x8f/0xa0 [<ffffffffa04f70d2>] process_discard+0x2a2/0x2d0 [dm_thin_pool] [<ffffffffa04f6a78>] ? remap_and_issue+0x38/0x50 [dm_thin_pool] [<ffffffffa04f7c3b>] process_deferred_bios+0x7b/0x230 [dm_thin_pool] [<ffffffffa04f7df0>] ? process_deferred_bios+0x230/0x230 [dm_thin_pool] [<ffffffffa04f7e42>] do_worker+0x52/0x60 [dm_thin_pool] [<ffffffff81056fa9>] process_one_work+0x129/0x450 [<ffffffff81059b9c>] worker_thread+0x17c/0x3c0 [<ffffffff81059a20>] ? manage_workers+0x120/0x120 [<ffffffff8105eabe>] kthread+0x9e/0xb0 [<ffffffff814ceda4>] kernel_thread_helper+0x4/0x10 [<ffffffff8105ea20>] ? kthread_freezable_should_stop+0x70/0x70 [<ffffffff814ceda0>] ? gs_change+0x13/0x13 ---[ end trace 7e0a523bc5e52692 ]--- Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
Fix a significant memory leak inadvertently introduced during simplification of cell_release_singleton() in commit 6f94a4c4 ("dm thin: fix stacked bi_next usage"). A cell's hlist_del() must be accompanied by a mempool_free(). Use __cell_release() to do this, like before. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 29 3月, 2012 9 次提交
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由 Joe Thornber 提交于
Add dm thin target arguments to control discard support. ignore_discard: Disables discard support no_discard_passdown: Don't pass discards down to the underlying data device, but just remove the mapping within the thin provisioning target. Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Joe Thornber 提交于
Support discards in the thin target. On discard the corresponding mapping(s) are removed from the thin device. If the associated block(s) are no longer shared the discard is passed to the underlying device. All bios other than discards now have an associated deferred_entry that is saved to the 'all_io_entry' in endio_hook. When non-discard IO completes and associated mappings are quiesced any discards that were deferred, via ds_add_work() in process_discard(), will be queued for processing by the worker thread. Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com> drivers/md/dm-thin.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++---- drivers/md/dm-thin.c | 172 ++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 158 insertions(+), 14 deletions(-)
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由 Joe Thornber 提交于
This patch contains the ground work needed for dm-thin to support discard. - Adds endio function that replaces shared_read_endio. - Introduce an explicit 'quiesced' flag into the new_mapping structure. Before, this was implicitly indicated by m->list being empty. - The map_info->ptr remains constant for the duration of a bio's trip through the thin target. Make it easier to reason about it. Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Alasdair G Kergon 提交于
Use dm_target_offset wrapper instead of referencing the awkward ti->begin explicitly. Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Joe Thornber 提交于
Support the use of an external _read only_ device as an origin for a thin device. Any read to an unprovisioned area of the thin device will be passed through to the origin. Writes trigger allocation of new blocks as usual. One possible use case for this would be VM hosts that want to run guests on thinly-provisioned volumes but have the base image on another device (possibly shared between many VMs). Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Mike Snitzer 提交于
The thin metadata format can only make use of a device that is <= THIN_METADATA_MAX_SECTORS (currently 15.9375 GB). Therefore, there is no practical benefit to using a larger device. However, it may be that other factors impose a certain granularity for the space that is allocated to a device (E.g. lvm2 can impose a coarse granularity through the use of large, >= 1 GB, physical extents). Rather than reject a larger metadata device, during thin-pool device construction, switch to allowing it but issue a warning if a device larger than THIN_METADATA_MAX_SECTORS_WARNING (16 GB) is provided. Any space over 15.9375 GB will not be used. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Joe Thornber 提交于
Commit unwritten data every second to prevent too much building up. Released blocks don't become available until after the next commit (for crash resilience). Prior to this patch commits were only triggered by a message to the target or a REQ_{FLUSH,FUA} bio. This allowed far too big a position to build up. The interval is hard-coded to 1 second. This is a sensible setting. I'm not making this user configurable, since there isn't much to be gained by tweaking this - and a lot lost by setting it far too high. Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Joe Thornber 提交于
Remove documentation for unimplemented 'trim' message. I'd planned a 'trim' target message for shrinking thin devices, but this is better handled via the discard ioctl. Signed-off-by: NJoe Thornber <ejt@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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由 Joe Thornber 提交于
Avoid using the bi_next field for the holder of a cell when deferring bios because a stacked device below might change it. Store the holder in a new field in struct cell instead. When a cell is created, the bio that triggered creation (the holder) was added to the same bio list as subsequent bios. In some cases we pass this holder bio directly to devices underneath. If those devices use the bi_next field there will be trouble... This also simplifies some code that had to work out which bio was the holder. Signed-off-by: NJoe Thornber <ejt@redhat.com> Cc: stable@kernel.org Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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- 01 11月, 2011 1 次提交
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由 Joe Thornber 提交于
Initial EXPERIMENTAL implementation of device-mapper thin provisioning with snapshot support. The 'thin' target is used to create instances of the virtual devices that are hosted in the 'thin-pool' target. The thin-pool target provides data sharing among devices. This sharing is made possible using the persistent-data library in the previous patch. The main highlight of this implementation, compared to the previous implementation of snapshots, is that it allows many virtual devices to be stored on the same data volume, simplifying administration and allowing sharing of data between volumes (thus reducing disk usage). Another big feature is support for arbitrary depth of recursive snapshots (snapshots of snapshots of snapshots ...). The previous implementation of snapshots did this by chaining together lookup tables, and so performance was O(depth). This new implementation uses a single data structure so we don't get this degradation with depth. For further information and examples of how to use this, please read Documentation/device-mapper/thin-provisioning.txt Signed-off-by: NJoe Thornber <thornber@redhat.com> Signed-off-by: NMike Snitzer <snitzer@redhat.com> Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
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