- 08 Aug, 2010 2 commits
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NeilBrown authored
Move the deletion of sysfs attributes from reconfig_mutex to open_mutex didn't really help as a process can try to take open_mutex while holding reconfig_mutex, so the same deadlock can happen, just requiring one more process to be involved in the chain. I looks like I cannot easily use locking to wait for the sysfs deletion to complete, so don't. The only things that we cannot do while the deletions are still pending is other things which can change the sysfs namespace: run, takeover, stop. Each of these can fail with -EBUSY. So set a flag while doing a sysfs deletion, and fail run, takeover, stop if that flag is set. This is suitable for 2.6.35.x Cc: stable@kernel.org Signed-off-by:NeilBrown <neilb@suse.de>
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Dan Williams authored
Commit b821eaa5 "md: remove ->changed and related code" moved revalidate_disk() under open_mutex, and lockdep noticed. [ INFO: possible circular locking dependency detected ] 2.6.32-mdadm-locking #1 ------------------------------------------------------- mdadm/3640 is trying to acquire lock: (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff811acecb>] revalidate_disk+0x5b/0x90 but task is already holding lock: (&mddev->open_mutex){+.+...}, at: [<ffffffffa055e07a>] do_md_stop+0x4a/0x4d0 [md_mod] which lock already depends on the new lock. It is suitable for 2.6.35.x Cc: <stable@kernel.org> Reported-by:
Przemyslaw Czarnowski <przemyslaw.hawrylewicz.czarnowski@intel.com> Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Signed-off-by:
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- 25 Jul, 2010 8 commits
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NeilBrown authored
dm makes this distinction between ->ctr and ->resume, so we need to too. Also get the new bitmap_load to clear out the bitmap first, as this is most consistent with the dm suspend/resume approach Signed-off-by: -
NeilBrown authored
1/ use md_unplug in bitmap.c as we will soon be using bitmaps under arrays with no queue attached. 2/ Don't bother plugging the queue when we set a bit in the bitmap. The reason for this was to encourage as many bits as possible to get set before we unplug and write stuff out. However every personality already plugs the queue after bitmap_startwrite either directly (raid1/raid10) or be setting STRIPE_BIT_DELAY which causes the queue to be plugged later (raid5). Signed-off-by: -
NeilBrown authored
If an array doesn't have a 'queue' then md_do_sync cannot unplug it. In that case it will have a 'plugger', so make that available to the mddev, and use it to unplug the array if needed. Signed-off-by: -
NeilBrown authored
md/raid5 uses the plugging infrastructure provided by the block layer and 'struct request_queue'. However when we plug raid5 under dm there is no request queue so we cannot use that. So create a similar infrastructure that is much lighter weight and use it for raid5. Signed-off-by: -
NeilBrown authored
dm uses scheduled work to raise events to user-space. So allow md device to have work_structs and schedule them on an error. Signed-off-by: -
NeilBrown authored
export entry points for starting and stopping md arrays. This will be used by a module to make md/raid5 work under dm. Also stop calling md_stop_writes from md_stop, as that won't work well with dm - it will want to call the two separately. Signed-off-by: -
NeilBrown authored
This functionality will be needed separately in a subsequent patch, so split it into it's own exported function. Signed-off-by: -
NeilBrown authored
When MD_CHANGE_CLEAN is set we might block in md_write_start. So we should only set it when fairly sure that something will clear it. There are two places where it is set so as to encourage a metadata update to record the progress of resync/recovery. This should only be done if the internal metadata update mechanisms are in use, which can be tested by by inspecting '->persistent'. Signed-off-by:
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- 20 Jul, 2010 1 commit
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NeilBrown authored
We will want md devices to live as dm targets where sysfs is not visible. So allow md to not connect to sysfs. Signed-off-by:
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- 23 Jun, 2010 3 commits
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NeilBrown authored
When an array is reshaped to have fewer devices, the reshape proceeds from the end of the devices to the beginning. If a device happens to be non-In_sync (which is possible but rare) we would normally update the ->recovery_offset as the reshape progresses. However that would be wrong as the recover_offset records that the early part of the device is in_sync, while in fact it would only be the later part that is in_sync, and in any case the offset number would be measured from the wrong end of the device. Relatedly, if after a reshape a spare is discovered to not be recoverred all the way to the end, not allow spare_active to incorporate it in the array. This becomes relevant in the following sample scenario: A 4 drive RAID5 is converted to a 6 drive RAID6 in a combined operation. The RAID5->RAID6 conversion will cause a 5 drive to be included as a spare, then the 5drive -> 6drive reshape will effectively rebuild that spare as it progresses. The 6th drive is treated as in_sync the whole time as there is never any case that we might consider reading from it, but must not because there is no valid data. If we interrupt this reshape part-way through and reverse it to return to a 5-drive RAID6 (or event a 4-drive RAID5), we don't want to update the recovery_offset - as that would be wrong - and we don't want to include that spare as active in the 5-drive RAID6 when the reversed reshape completed and it will be mostly out-of-sync still. Signed-off-by: -
NeilBrown authored
Most array level changes leave the list of devices largely unchanged, possibly causing one at the end to become redundant. However conversions between RAID0 and RAID10 need to renumber all devices (except 0). This renumbering is currently being done in the ->run method when the new personality takes over. However this is too late as the common code in md.c might already have invalidated some of the devices if they had a ->raid_disk number that appeared to high. Moving it into the ->takeover method is too early as the array is still active at that time and wrong ->raid_disk numbers could cause confusion. So add a ->new_raid_disk field to mdk_rdev_s and use it to communicate the new raid_disk number. Now the common code knows exactly which devices need to be renumbered, and which can be invalidated, and can do it all at a convenient time when the array is suspend. It can also update some symlinks in sysfs which previously were not be updated correctly. Reported-by:
Maciej Trela <maciej.trela@intel.com> Signed-off-by:
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NeilBrown authored
Commit b821eaa5 broke partition detection for md arrays. The logic was almost right. However if revalidate_disk is called when the device is not yet open, bdev->bd_disk won't be set, so the flush_disk() Call will not set bd_invalidated. So when md_open is called we still need to ensure that ->bd_invalidated gets set. This is easily done with a call to check_disk_size_change in the place where the offending commit removed check_disk_change. At the important times, the size will have changed from 0 to non-zero, so check_disk_size_change will set bd_invalidated. Tested-by:
Duncan <1i5t5.duncan@cox.net> Reported-by:
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- 21 May, 2010 1 commit
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Eric W. Biederman authored
The problem. When implementing a network namespace I need to be able to have multiple network devices with the same name. Currently this is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and potentially a few other directories of the form /sys/ ... /net/*. What this patch does is to add an additional tag field to the sysfs dirent structure. For directories that should show different contents depending on the context such as /sys/class/net/, and /sys/devices/virtual/net/ this tag field is used to specify the context in which those directories should be visible. Effectively this is the same as creating multiple distinct directories with the same name but internally to sysfs the result is nicer. I am calling the concept of a single directory that looks like multiple directories all at the same path in the filesystem tagged directories. For the networking namespace the set of directories whose contents I need to filter with tags can depend on the presence or absence of hotplug hardware or which modules are currently loaded. Which means I need a simple race free way to setup those directories as tagged. To achieve a reace free design all tagged directories are created and managed by sysfs itself. Users of this interface: - define a type in the sysfs_tag_type enumeration. - call sysfs_register_ns_types with the type and it's operations - sysfs_exit_ns when an individual tag is no longer valid - Implement mount_ns() which returns the ns of the calling process so we can attach it to a sysfs superblock. - Implement ktype.namespace() which returns the ns of a syfs kobject. Everything else is left up to sysfs and the driver layer. For the network namespace mount_ns and namespace() are essentially one line functions, and look to remain that. Tags are currently represented a const void * pointers as that is both generic, prevides enough information for equality comparisons, and is trivial to create for current users, as it is just the existing namespace pointer. The work needed in sysfs is more extensive. At each directory or symlink creating I need to check if the directory it is being created in is a tagged directory and if so generate the appropriate tag to place on the sysfs_dirent. Likewise at each symlink or directory removal I need to check if the sysfs directory it is being removed from is a tagged directory and if so figure out which tag goes along with the name I am deleting. Currently only directories which hold kobjects, and symlinks are supported. There is not enough information in the current file attribute interfaces to give us anything to discriminate on which makes it useless, and there are no potential users which makes it an uninteresting problem to solve. Signed-off-by:
Eric W. Biederman <ebiederm@xmission.com> Signed-off-by:
Benjamin Thery <benjamin.thery@bull.net> Signed-off-by:
Greg Kroah-Hartman <gregkh@suse.de>
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- 18 May, 2010 22 commits
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NeilBrown authored
Devices which know that they are spares do not really need to have an event count that matches the rest of the array, so there are no data-in-sync issues. It is enough that the uuid matches. So remove the requirement that the event count is up-to-date. We currently still write out and event count on spares, but this allows us in a year or 3 to stop doing that completely. Signed-off-by: -
NeilBrown authored
When updating the event count for a simple clean <-> dirty transition, we try to avoid updating the spares so they can safely spin-down. As the event_counts across an array must be +/- 1, this means decrementing the event_count on a dirty->clean transition. This is not always safe and we have to avoid the unsafe time. We current do this with a misguided idea about it being safe or not depending on whether the event_count is odd or even. This approach only works reliably in a few common instances, but easily falls down. So instead, simply keep internal state concerning whether it is safe or not, and always assume it is not safe when an array is first assembled. Signed-off-by: -
NeilBrown authored
Some time ago we stopped the clean/active metadata updates from being written to a 'spare' device in most cases so that it could spin down and say spun down. Device failure/removal etc are still recorded on spares. However commit 51d5668c broke this 50% of the time, depending on whether the event count is even or odd. The change log entry said: This means that the alignment between 'odd/even' and 'clean/dirty' might take a little longer to attain, how ever the code makes no attempt to create that alignment, so it could take arbitrarily long. So when we find that clean/dirty is not aligned with odd/even, force a second metadata-update immediately. There are already cases where a second metadata-update is needed immediately (e.g. when a device fails during the metadata update). We just piggy-back on that. Reported-by:
Joe Bryant <tenminjoe@yahoo.com> Signed-off-by:
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Dan Williams authored
e.g. allow md to interpret 'echo 4 > md/level' as a request for raid4. Signed-off-by: -
Dan Williams authored
Level modifications change the output of mdstat. The mdmon manager thread is interested in these events for external metadata management. Signed-off-by: -
NeilBrown authored
This is - unnecessary because mddev_suspend is always followed by a call to ->stop, and each ->stop unregisters the thread, and - a problem as it makes it awkwards to suspend and then resume a device as we will want later. Signed-off-by: -
NeilBrown authored
This is a simple factorisation that makes mddev_find easier to read. Signed-off-by: -
NeilBrown authored
We used to pass the personality make_request function direct to the block layer so the first argument had to be a queue. But now we have the intermediary md_make_request so it makes at lot more sense to pass a struct mddev_s. It makes it possible to have an mddev without its own queue too. Signed-off-by: -
NeilBrown authored
This moves the call to the other side of set_readonly, but that should not be an issue. This encapsulates in 'md_stop' all of the functionality for internally stopping the array, leaving all the interactions with externalities (sysfs, request_queue, gendisk) in do_md_stop. Signed-off-by: -
NeilBrown authored
Using do_md_stop to set an array to read-only is a little confusing. Now most of the common code has been factored out, split md_set_readonly off in to a separate function. Signed-off-by: -
NeilBrown authored
Further refactoring of do_md_stop. This one requires some explanation as it takes code from different places in do_md_stop, so some re-ordering happens. We only get into this part of do_md_stop if there are no active opens of the device, so no writes can be happening and the device must have been flushed. In md_stop_writes we want to stop any internal sources of writes - i.e. resync - and flush out the metadata. The only code that was previously before some of this code is code to clean up the queue, the mddev, the gendisk, or sysfs, all of which is probably better after code that makes active changes (i.e. triggers writes). Signed-off-by: -
NeilBrown authored
do_md_stop is large and clunky, so hard to understand. This is a first step of refactoring, pulling two simple sub-functions out. Signed-off-by: -
NeilBrown authored
As part of relaxing the binding between an mddev and gendisk, we separate do_md_run into two functions. md_run does all the work internal to md do_md_run calls md_run and makes and changes to gendisk that are required. Signed-off-by: -
NeilBrown authored
We set ->changed to 1 and call check_disk_change at the end of md_open so that bd_invalidated would be set and thus partition rescan would happen appropriately. Now that we call revalidate_disk directly, which sets bd_invalidates, that indirection is no longer needed and can be removed. Signed-off-by: -
NeilBrown authored
Using ->array_sectors rather than get_capacity() is more direct and is a step towards relaxing the tight connection between mddev and gendisk. Signed-off-by: -
NeilBrown authored
While I generally prefer letting personalities do as much as possible, given that we have a central md_make_request anyway we may as well use it to simplify code. Also this centralises knowledge of ->gendisk which will help later. Signed-off-by: -
Maciej Trela authored
Level changes can be very significant, so make sure to notify them via sysfs. Signed-off-by:
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NeilBrown authored
When metadata is being managed by user-space, md doesn't know what the maximum number of devices allowed in an array is so ->max_disks is 0. In this case we should allow any (+ve) number of disks. Signed-off-by: -
Maciej Trela authored
Writing "none" to "../md/dev-xx/slot" removes that device from being an active part of the array, but it didn't set ->raid_disk to -1 to record this fact. Signed-off-by:
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Trela, Maciej authored
Signed-off-by:
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Trela Maciej authored
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NeilBrown authored
This was needed when sysfs files could only be 'notified' from process context. Now that we have sys_notify_direct, we can call it directly from an interrupt. Signed-off-by:
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- 17 May, 2010 2 commits
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NeilBrown authored
Some levels expect the 'redundancy group' to be present, others don't. So when we change level of an array we might need to add or remove this group. This requires fixing up the current practice of overloading ->private to indicate (when ->pers == NULL) that something needs to be removed. So create a new ->to_remove to fill that role. When changing levels, we may need to add or remove attributes. When changing RAID5 -> RAID6, we both add and remove the same thing. It is important to catch this and optimise it out as the removal is delayed until a lock is released, so trying to add immediately would cause problems. Cc: stable@kernel.org Signed-off-by: -
NeilBrown authored
When an array is stopped we need to remove some sysfs files which are dependent on the type of array. We need to delay that deletion as deleting them while holding reconfig_mutex can lead to deadlocks. We currently delay them until the array is completely destroyed. However it is possible to deactivate and then reactivate the array. It is also possible to need to remove sysfs files when changing level, which can potentially happen several times before an array is destroyed. So we need to delete these files more promptly: as soon as reconfig_mutex is dropped. We need to ensure this happens before do_md_run can restart the array, so we use open_mutex for some extra locking. This is not deadlock prone. Cc: stable@kernel.org Signed-off-by:
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- 11 May, 2010 1 commit
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Dan Williams authored
When the user sets the block device to readwrite then the mddev should follow suit. Otherwise, the BUG_ON in md_write_start() will be set to trigger. The reverse direction, setting mddev->ro to match a set readonly request, can be ignored because the blkdev level readonly flag precludes the need to have mddev->ro set correctly. Nevermind the fact that setting mddev->ro to 1 may fail if the array is in use. Cc: <stable@kernel.org> Signed-off-by:
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