- 22 Dec, 2011 34 commits
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NeilBrown authored
In general mddev->raid_disks can change unexpectedly while conf->raid_disks will only change in a very controlled way. So change some uses of one to the other. The use of mddev->raid_disks will not cause actually problems but this way is more consistent and safer in the long term. Signed-off-by:NeilBrown <neilb@suse.de>
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NeilBrown authored
When attempting to add a spare to a RAID10 array, also consider adding it as a replacement for a want_replacement device. Signed-off-by: -
NeilBrown authored
If a Replacement is seen, file it as such. If we see two replacements (or two normal devices) for the one slot, abort. Signed-off-by: -
NeilBrown authored
When recovery finish and spare_active is called, check for a replace that might have just become fully synced and mark it as such, marking the original as failed. Then when the original is removed, move the replacement into its position. This means that 'replacement' and spontaneously become NULL in some situations. Make sure we check for those. It also means that 'rdev' and 'replacement' could appear to be identical - check for that too. Signed-off-by: -
NeilBrown authored
If there is a replacement device, then recover to it, reading from any drives - maybe the one being replaced, maybe not. Signed-off-by: -
NeilBrown authored
If we need to resync an array which has replacement devices, we always write any block checked to every replacement. If the resync was bitmap-based resync we will then complete the replacement normally. If it was a full resync, we mark the replacements as fully recovered when the resync finishes so no further recovery is needed. Signed-off-by: -
NeilBrown authored
When writing, we need to submit two writes, one to the original, and one to the replacements - if there is a replacement. If the write to the replacement results in a write error we just fail the device. We only try to record write errors to the original. This only handles writing new data. Writing for resync/recovery will come later. Signed-off-by: -
NeilBrown authored
Enhance raid10_remove_disk to be able to remove ->replacement as well as ->rdev Signed-off-by: -
NeilBrown authored
When reading (for array reads, not for recovery etc) we read from the replacement device if it has recovered far enough. This requires storing the chosen rdev in the 'r10_bio' so we can make sure to drop the ref on the right device when the read finishes. Signed-off-by: -
NeilBrown authored
It makes more sense to return an rdev than just an index as read_balance() gets a reference to the rdev and so returning the pointer make this more idiomatic. This will be needed in a future patch when we might return a 'replacement' rdev instead of the main rdev. Signed-off-by: -
NeilBrown authored
Allow each slot in the RAID10 to have 2 devices, the want_replacement and the replacement. Also an r10bio to have 2 bios, and for resync/recovery allocate the second bio if there are any replacement devices. Signed-off-by: -
NeilBrown authored
Now that WantReplacement drives are replaced cleanly, mark a drive as WantReplacement when we see a write error. It might get failed soon so the WantReplacement flag is irrelevant, but if the write error is recorded in the bad block log, we still want to activate any spare that might be available. Reviewed-by:
Dan Williams <dan.j.williams@intel.com> Signed-off-by:
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NeilBrown authored
When attempting to add a spare to a RAID[456] array, also consider adding it as a replacement for a want_replacement device. This requires that common md code attempt hot_add even when the array is not formally degraded. Reviewed-by:
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NeilBrown authored
If a Replacement is seen, file it as such. If we see two replacements (or two normal devices) for the one slot, abort. Reviewed-by:
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NeilBrown authored
When recovery completes - as reported by a call to ->spare_active, we clear In_sync on the original and set it on the replacement. Then when the original gets removed we move the replacement from 'replacement' to 'rdev'. This could race with other code that is looking at these pointers, so we use memory barriers and careful ordering to ensure that a reader might see one device twice, but never no devices. Then the readers guard against using both devices, which could only happen when writing. Signed-off-by: -
NeilBrown authored
During recovery we want to write to the replacement but not the original. So we have two new flags - R5_NeedReplace if this stripe has a replacement that needs to be written at some stage - R5_WantReplace if NeedReplace, and the data is available, and a 'sync' has been requested on this stripe. We also distinguish between 'sync and replace' which need to read all other devices, and 'replace' which only needs to read the devices being replaced. Note that during resync we always write to any replacement device. It might not need to be written to, but as we don't read to compare, we have to write to be sure. Signed-off-by: -
NeilBrown authored
When writing, we need to submit two writes, one to the original, and one to the replacement - if there is a replacement. If the write to the replacement results in a write error, we just fail the device. We only try to record write errors to the original. When writing for recovery, we shouldn't write to the original. This will be addressed in a subsequent patch that generally addresses recovery. Reviewed-by:
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NeilBrown authored
Enhance raid5_remove_disk to be able to remove ->replacement as well as ->rdev. Reviewed-by:
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NeilBrown authored
If a replacement device is present and has been recovered far enough, then use it for reading into the stripe cache. If we get an error we don't try to repair it, we just fail the device. A replacement device that gives errors does not sound sensible. This requires removing the setting of R5_ReadError when we get a read error during a read that bypasses the cache. It was probably a bad idea anyway as we don't know that every block in the read caused an error, and it could cause ReadError to be set for the replacement device, which is bad. Signed-off-by: -
NeilBrown authored
We current initialise some fields of a bio when preparing a stripe_head, and again just before submitting the request. Remove the duplication by only setting the fields that lower level devices don't touch in raid5_build_block, and only set the changeable fields in ops_run_io. Reviewed-by:
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NeilBrown authored
Remove some #defines that are no longer used, and replace some others with an enum. And remove an unused field. Reviewed-by:
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NeilBrown authored
Just enhance data structures to record a second device per slot to be used as a 'replacement' device, replacing the original. We also have a second bio in each slot in each stripe_head. This will only be used when writing to the array - we need to write to both the original and the replacement at the same time, so will need two bios. For now, only try using the replacement drive for aligned-reads. In this case, we prefer the replacement if it has been recovered far enough, otherwise use the original. This includes a small enhancement. Previously we would only do aligned reads if the target device was fully recovered. Now we also do them if it has recovered far enough. Reviewed-by:
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NeilBrown authored
hot-replace is a feature being added to md which will allow a device to be replaced without removing it from the array first. With hot-replace a spare can be activated and recovery can start while the original device is still in place, thus allowing a transition from an unreliable device to a reliable device without leaving the array degraded during the transition. It can also be use when the original device is still reliable but it not wanted for some reason. This will eventually be supported in RAID4/5/6 and RAID10. This patch adds a super-block flag to distinguish the replacement device. If an old kernel sees this flag it will reject the device. It also adds two per-device flags which are viewable and settable via sysfs. "want_replacement" can be set to request that a device be replaced. "replacement" is set to show that this device is replacing another device. The "rd%d" links in /sys/block/mdXx/md only apply to the original device, not the replacement. We currently don't make links for the replacement - there doesn't seem to be a need. Signed-off-by: -
NeilBrown authored
Soon an array will be able to have multiple devices with the same raid_disk number (an original and a replacement). So removing a device based on the number won't work. So pass the actual device handle instead. Reviewed-by:
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NeilBrown authored
When setting the slot number on a device in an active array we currently check that the number is not already in use. We then call into the personality's hot_add_disk function which performs the same test and returns the same error. Thus the common test is not needed. As we will shortly be changing some personalities to allow duplicates in some cases (to support hot-replace), the common test will become inconvenient. So remove the common test. Reviewed-by:
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NeilBrown authored
For each active region corresponding to a bit in the bitmap with have a 14bit counter (and some flags). This counts number of active writes + bit in the on-disk bitmap + delay-needed. The "delay-needed" is because we always want a delay before clearing a bit. So the number here is normally number of active writes plus 2. If there have been no writes for a while, we drop to 1. If still no writes we clear the bit and drop to 0. So for consistency, when setting bit from the on-disk bitmap or by request from user-space it is best to set the counter to '2' to start with. In particular we might also set the NEEDED_MASK flag at this time, and in all other cases NEEDED_MASK is only set when the counter is 2 or more. Signed-off-by: -
Steven Rostedt authored
While using etags to find free_pages(), I stumbled across this debug definition of free_pages() that is to be used while debugging some raid code in userspace. The __get_free_pages() allocates the correct size, but the free_pages() does not match. free_pages(), like __get_free_pages(), takes an order and not a size. Acked-by:
H. Peter Anvin <hpa@zytor.com> Signed-off-by:
Steven Rostedt <rostedt@goodmis.org> Signed-off-by:
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NeilBrown authored
When an array is being reshaped to change the number of devices, the two halves can be differently degraded. e.g. one could be missing a device and the other not. So we need to be more careful about calculating the 'degraded' attribute. Instead of just inc/dec at appropriate times, perform a full re-calculation examining both possible cases. This doesn't happen often so it not a big cost, and we already have most of the code to do it. Signed-off-by: -
NeilBrown authored
We have a variable 'mddev' in this function, but repeatedly get the same value by dereferencing bitmap->mddev. There is room for simplification here... Signed-off-by: -
NeilBrown authored
The info is already available in /proc/mdstat and /sys/block in an accessible form so there is no point in putting a road-block in the ioctl for information gathering. Signed-off-by: -
NeilBrown authored
commit d0a4bb49 introduced a regression which is annoying but fairly harmless. When writing to an array that is undergoing recovery (a spare in being integrated into the array), writing to the array will set bits in the bitmap, but they will not be cleared when the write completes. For bits covering areas that have not been recovered yet this is not a problem as the recovery will clear the bits. However bits set in already-recovered region will stay set and never be cleared. This doesn't risk data integrity. The only negatives are: - next time there is a crash, more resyncing than necessary will be done. - the bitmap doesn't look clean, which is confusing. While an array is recovering we don't want to update the 'events_cleared' setting in the bitmap but we do still want to clear bits that have very recently been set - providing they were written to the recovering device. So split those two needs - which previously both depended on 'success' and always clear the bit of the write went to all devices. Signed-off-by:
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NeilBrown authored
Before performing a recovery we try to remove any spares that might not be working, then add any that might have become relevant. Currently we abort on the first spare that cannot be added. This is a false optimisation. It is conceivable that - depending on rules in the personality - a subsequent spare might be accepted. Also the loop does other things like count the available spares and reset the 'recovery_offset' value. If we abort early these might not happen properly. So remove the early abort. In particular if you have an array what is undergoing recovery and which has extra spares, then the recovery may not restart after as reboot as the could of 'spares' might end up as zero. Reported-by:
Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by:
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NeilBrown authored
While reshaping a degraded array (as when reshaping a RAID0 by first converting it to a degraded RAID4) we currently get confused about which devices are in_sync. In most cases we get it right, but in the region that is being reshaped we need to treat non-failed devices as in-sync when we have the data but haven't actually written it out yet. Reported-by:
Adam Kwolek <adam.kwolek@intel.com> Signed-off-by:
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NeilBrown authored
commit d70ed2e4 broke hot-add to a linear array. After that commit, metadata if not written to devices until they have been fully integrated into the array as determined by saved_raid_disk. That patch arranged to clear that field after a recovery completed. However for linear arrays, there is no recovery - the integration is instantaneous. So we need to explicitly clear the saved_raid_disk field. Signed-off-by:
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- 09 Dec, 2011 1 commit
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Adam Kwolek authored
NULL pointer access causes crash in raid5 module. Signed-off-by:
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- 08 Dec, 2011 5 commits
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NeilBrown authored
Once a device is failed we really want to completely ignore it. It should go away soon anyway. In particular the presence of bad blocks on it should not cause us to block as we won't be trying to write there anyway. So as soon as we can check if a device is Faulty, do so and pretend that it is already gone if it is Faulty. Signed-off-by: -
NeilBrown authored
When we mark blocks as bad we need them to be acknowledged by the metadata handler promptly. For an in-kernel metadata handler that was already being done. But for an external metadata handler we need to alert it of the change by sending a notification through the sysfs file. This adds that notification. Signed-off-by: -
NeilBrown authored
Once a device is marked Faulty the badblocks - whether acknowledged or not - become irrelevant. So they shouldn't cause the device to be marked as Blocked. Without this patch, a process might write "-blocked" to clear the Blocked status, but while that will correctly fail the device, it won't remove the apparent 'blocked' status. Signed-off-by: -
NeilBrown authored
When we are accessing an mddev via sysfs we know that the mddev cannot disappear because it has an embedded kobj which is refcounted by sysfs. And we also take the mddev_lock. However this is not enough. The final mddev_put could have been called and the mddev_delayed_delete is waiting for sysfs to let go so it can destroy the kobj and mddev. In this state there are a lot of changes that should not be attempted. To to guard against this we: - initialise mddev->all_mddevs in on last put so the state can be easily detected. - in md_attr_show and md_attr_store, check ->all_mddevs under all_mddevs_lock and mddev_get the mddev if it still appears to be active. This means that if we get to sysfs as the mddev is being deleted we will get -EBUSY. rdev_attr_store and rdev_attr_show are similar but already have sufficient protection. They check that rdev->mddev still points to mddev after taking mddev_lock. As this is cleared before delayed removal which can only be requested under the mddev_lock, this ensure the rdev and mddev are still alive. Signed-off-by: -
NeilBrown authored
We like md devices to disappear when they really are not needed. However it is not possible to tell from the current state whether it is needed or not. We can only tell from recent history of changes. In particular immediately after we create an md device it looks very similar to immediately after we have finished with it. So we always preserve a newly created md device until something significant happens. This state is stored in 'hold_active'. The normal case is to keep it until an ioctl happens, as that will normally either activate it, or explicitly de-activate it. If it doesn't then it was probably created by mistake and it is now time to get rid of it. We can also modify an array via sysfs (instead of via ioctl) and we currently treat any change via sysfs like an ioctl as a sign that if it now isn't more active, it should be destroyed. However this is not appropriate as changes made via sysfs are more gradual so we should look for a more definitive change. So this patch only clears 'hold_active' from UNTIL_IOCTL to clear when the array_state is changed via sysfs. Other changes via sysfs are ignored. Signed-off-by:
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