- 01 Nov, 2015 5 commits
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Shaohua Li authored
Before we write stripe data to raid disks, we must guarantee stripe data is settled down in log disk. To do this, we flush log disk cache and wait the flush finish. That wait introduces sleep time in raid5d thread and impact performance. This patch moves the log disk cache flush process to the stripe handling state machine, which can remove the wait in raid5d. Signed-off-by:
Shaohua Li <shli@fb.com> Signed-off-by:
NeilBrown <neilb@suse.com>
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Shaohua Li authored
Now log is safe to enable for raid array with cache disk Signed-off-by:
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Shaohua Li authored
If cache(log) support is enabled, don't allow resize/reshape in current stage. In the future, we can flush all data from cache(log) to raid before resize/reshape and then allow resize/reshape. Signed-off-by:
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Shaohua Li authored
With log enabled, r5l_write_stripe will add the stripe to log. With batch, several stripes are linked together. The stripes must be in the same state. While with log, the log/reclaim unit is stripe, we can't guarantee the several stripes are in the same state. Disabling batch for log now. Signed-off-by:
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Shaohua Li authored
crc32c has lower overhead with cpu acceleration. It's a shame I didn't use it in first post, sorry. This changes disk format, but we are still ok in current stage. V2: delete unnecessary type conversion as pointed out by Bart Signed-off-by:
Bart Van Assche <bart.vanassche@sandisk.com>
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- 24 Oct, 2015 13 commits
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Shaohua Li authored
This is the log recovery support. The process is quite straightforward. We scan the log and read all valid meta/data/parity into memory. If a stripe's data/parity checksum is correct, the stripe will be recoveried. Otherwise, it's discarded and we don't scan the log further. The reclaim process guarantees stripe which starts to be flushed raid disks has completed data/parity and has correct checksum. To recovery a stripe, we just copy its data/parity to corresponding raid disks. The trick thing is superblock update after recovery. we can't let superblock point to last valid meta block. The log might look like: | meta 1| meta 2| meta 3| meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If superblock points to meta 1, we write a new valid meta 2n. If crash happens again, new recovery will start from meta 1. Since meta 2n is valid, recovery will think meta 3 is valid, which is wrong. The solution is we create a new meta in meta2 with its seq == meta 1's seq + 10 and let superblock points to meta2. recovery will not think meta 3 is a valid meta, because its seq is wrong Signed-off-by:
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Shaohua Li authored
This is the reclaim support for raid5 log. A stripe write will have following steps: 1. reconstruct the stripe, read data/calculate parity. ops_run_io prepares to write data/parity to raid disks 2. hijack ops_run_io. stripe data/parity is appending to log disk 3. flush log disk cache 4. ops_run_io run again and do normal operation. stripe data/parity is written in raid array disks. raid core can return io to upper layer. 5. flush cache of all raid array disks 6. update super block 7. log disk space used by the stripe can be reused In practice, several stripes consist of an io_unit and we will batch several io_unit in different steps, but the whole process doesn't change. It's possible io return just after data/parity hit log disk, but then read IO will need read from log disk. For simplicity, IO return happens at step 4, where read IO can directly read from raid disks. Currently reclaim run if there is specific reclaimable space (1/4 disk size or 10G) or we are out of space. Reclaim is just to free log disk spaces, it doesn't impact data consistency. The size based force reclaim is to make sure log isn't too big, so recovery doesn't scan log too much. Recovery make sure raid disks and log disk have the same data of a stripe. If crash happens before 4, recovery might/might not recovery stripe's data/parity depending on if data/parity and its checksum matches. In either case, this doesn't change the syntax of an IO write. After step 3, stripe is guaranteed recoverable, because stripe's data/parity is persistent in log disk. In some cases, log disk content and raid disks content of a stripe are the same, but recovery will still copy log disk content to raid disks, this doesn't impact data consistency. space reuse happens after superblock update and cache flush. There is one situation we want to avoid. A broken meta in the middle of a log causes recovery can't find meta at the head of log. If operations require meta at the head persistent in log, we must make sure meta before it persistent in log too. The case is stripe data/parity is in log and we start write stripe to raid disks (before step 4). stripe data/parity must be persistent in log before we do the write to raid disks. The solution is we restrictly maintain io_unit list order. In this case, we only write stripes of an io_unit to raid disks till the io_unit is the first one whose data/parity is in log. The io_unit list order is important for other cases too. For example, some io_unit are reclaimable and others not. They can be mixed in the list, we shouldn't reuse space of an unreclaimable io_unit. Includes fixes to problems which were... Reported-by:
kbuild test robot <fengguang.wu@intel.com> Signed-off-by:
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Shaohua Li authored
This introduces a simple log for raid5. Data/parity writing to raid array first writes to the log, then write to raid array disks. If crash happens, we can recovery data from the log. This can speed up raid resync and fix write hole issue. The log structure is pretty simple. Data/meta data is stored in block unit, which is 4k generally. It has only one type of meta data block. The meta data block can track 3 types of data, stripe data, stripe parity and flush block. MD superblock will point to the last valid meta data block. Each meta data block has checksum/seq number, so recovery can scan the log correctly. We store a checksum of stripe data/parity to the metadata block, so meta data and stripe data/parity can be written to log disk together. otherwise, meta data write must wait till stripe data/parity is finished. For stripe data, meta data block will record stripe data sector and size. Currently the size is always 4k. This meta data record can be made simpler if we just fix write hole (eg, we can record data of a stripe's different disks together), but this format can be extended to support caching in the future, which must record data address/size. For stripe parity, meta data block will record stripe sector. It's size should be 4k (for raid5) or 8k (for raid6). We always store p parity first. This format should work for caching too. flush block indicates a stripe is in raid array disks. Fixing write hole doesn't need this type of meta data, it's for caching extension. Signed-off-by:
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Shaohua Li authored
When a stripe finishes construction, we write the stripe to raid in ops_run_io normally. With log, we do a bunch of other operations before the stripe is written to raid. Mainly write the stripe to log disk, flush disk cache and so on. The operations are still driven by raid5d and run in the stripe state machine. We introduce a new state for such stripe (trapped into log). The stripe is in this state from the time it first enters ops_run_io (finish construction) to the time it is written to raid. Since we know the state is only for log, we bypass other check/operation in handle_stripe. Signed-off-by:
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Shaohua Li authored
Next several patches use some raid5 functions, rename them with raid5 prefix and export out. Signed-off-by:
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Shaohua Li authored
Journal device stores data in a log structure. We need record the log start. Here we override md superblock recovery_offset for this purpose. This field of a journal device is meaningless otherwise. Signed-off-by:
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Song Liu authored
Next patches will use a disk as raid5/6 journaling. We need a new disk role to present the journal device and add MD_FEATURE_JOURNAL to feature_map for backward compability. Signed-off-by:
Song Liu <songliubraving@fb.com> Signed-off-by:
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Song Liu authored
Add the following two macros for special roles: spare and faulty MD_DISK_ROLE_SPARE 0xffff MD_DISK_ROLE_FAULTY 0xfffe Add MD_DISK_ROLE_MAX 0xff00 as the maximal possible regular role, and minimal value of special role. Signed-off-by:
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Goldwyn Rodrigues authored
To incorporate --grow feature executed on one node, other nodes need to acknowledge the change in number of disks. Call update_raid_disks() to update internal data structures. This leads to call check_reshape() -> md_allow_write() -> md_update_sb(), this results in a deadlock. This is done so it can safely allocate memory (which might trigger writeback which might write to raid1). This is not required for md with a bitmap. In the clustered case, we don't perform md_update_sb() in md_allow_write(), but in do_md_run(). Also we disable safemode for clustered mode. mddev->recovery_cp need not be set in check_sb_changes() because this is required only when a node reads another node's bitmap. mddev->recovery_cp (which is read from sb->resync_offset), is set only if mddev is in_sync. Since we disabled safemode, in_sync is set to zero. In a clustered environment, the MD may not be in sync because another node could be writing to it. So make sure that in_sync is not set in case of clustered node in __md_stop_writes(). Signed-off-by:
Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by:
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NeilBrown authored
The arg isn't used, so its presence is only confusing. Signed-off-by: -
NeilBrown authored
It is common practice in the kernel to leave out this case. It isn't needed and adds little if any value. Signed-off-by: -
NeilBrown authored
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Guoqing Jiang authored
This patches fixes sparse warnings like incorrect type in assignment (different base types), cast to restricted __le64. Reported-by:
Guoqing Jiang <gqjiang@suse.com> Signed-off-by:
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- 16 Oct, 2015 1 commit
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NeilBrown authored
As cmsg.raid_slot is le32, comparing for >0 is not meaningful. So introduce cpu-endian 'raid_slot' and only assign to cmsg.raid_slot when we know value is valid. Reported-by:
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- 13 Oct, 2015 1 commit
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git://github.com/goldwynr/linuxNeilBrown authored
md-cluster: A better way for METADATA_UPDATED processing The processing of METADATA_UPDATED message is too simple and prone to errors. Besides, it would not update the internal data structures as required. This set of patches reads the superblock from one of the device of the MD and checks for changes in the in-memory data structures. If there is a change, it performs the necessary actions to keep the internal data structures as it would be in the primary node. An example is if a devices turns faulty. The algorithm is: 1. The initiator node marks the device as faulty and updates the superblock 2. The initiator node sends METADATA_UPDATED with an advisory device number to the rest of the nodes. 3. The receiving node on receiving the METADATA_UPDATED message 3.1 Reads the superblock 3.2 Detects a device has failed by comparing with memory structure 3.3 Calls the necessary functions to record the failure and get the device out of the active array. 3.4 Acknowledges the message. The patch series also fixes adding the disk which was impacted because of the changes. Patches can also be found at https://github.com/goldwynr/linux branch md-next Changes since V2: - Fix status synchrnoization after --add and --re-add operations - Included Guoqing's patches on endian correctness, zeroing cmsg etc - Restructure add_new_disk() and cancel()
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- 12 Oct, 2015 18 commits
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Guoqing Jiang authored
We shouldn't run related funs of md_cluster_ops in case metadata_update_start returned failure. Signed-off-by: -
Guoqing Jiang authored
For cluster raid, we should not kick it from array if the disk can't be remove from array successfully. Signed-off-by:
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Guoqing Jiang authored
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Guoqing Jiang authored
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Guoqing Jiang authored
During the past test, the node occasionally received the msg which is sent from itself, this case should not happen in theory, but it is better to avoid it in case something wrong happened. Signed-off-by:
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Guoqing Jiang authored
Since slot will be set within _sendmsg, we can remove the redundant code in resync_info_update. Signed-off-by: -
Guoqing Jiang authored
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Goldwyn Rodrigues authored
The receive daemon prints kernel messages for every network message received. This would fill the kernel message log with unnecessary messages. Remove the pr_info() messages. Signed-off-by: -
Goldwyn Rodrigues authored
Adding the disk worked incorrectly with the new reload code. Fix it: - No operation should be performed on rdev marked as Candidate - After a metadata update operation, kick disk if role is 0xfffe else clear Candidate bit and continue with the regular change check. - Saving the mode of the lock resource to check if token lock is already locked, because it can be called twice while adding a disk. However, unlock_comm() must be called only once. - add_new_disk() is called by the node initiating the --add operation. If it needs to be canceled, call add_new_disk_cancel(). The operation is completed by md_update_sb() which will write and unlock the communication. Signed-off-by: -
Goldwyn Rodrigues authored
Resync or recovery must be performed by only one node at a time. A DLM lock resource, resync_lockres provides the mutual exclusion so that only one node performs the recovery/resync at a time. If a node is unable to get the resync_lockres, because recovery is being performed by another node, it set MD_RECOVER_NEEDED so as to schedule recovery in the future. Remove the debug message in resync_info_update() used during development. Signed-off-by: -
Goldwyn Rodrigues authored
In a clustered environment, a change such as marking a device faulty, can be recorded by any of the nodes. This is communicated to all the nodes and re-recording such a change is unnecessary, and quite often pretty disruptive. With this patch, just before the update, we detect for the changes and if the changes are already in superblock, we abort the update after clearing all the flags Signed-off-by: -
Goldwyn Rodrigues authored
md_reload_sb is too simplistic and it explicitly needs to determine the changes made by the writing node. However, there are multiple areas where a simple reload could fail. Instead, read the superblock of one of the "good" rdevs and update the necessary information: - read the superblock into a newly allocated page, by temporarily swapping out rdev->sb_page and calling ->load_super. - if that fails return - if it succeeds, call check_sb_changes 1. iterates over list of active devices and checks the matching dev_roles[] value. If that is 'faulty', the device must be marked as faulty - call md_error to mark the device as faulty. Make sure not to set CHANGE_DEVS and wakeup mddev->thread or else it would initiate a resync process, which is the responsibility of the "primary" node. - clear the Blocked bit - Call remove_and_add_spares() to hot remove the device. If the device is 'spare': - call remove_and_add_spares() to get the number of spares added in this operation. - Reduce mddev->degraded to mark the array as not degraded. 2. reset recovery_cp - read the rest of the rdevs to update recovery_offset. If recovery_offset is equal to MaxSector, call spare_active() to set it In_sync This required that recovery_offset be initialized to MaxSector, as opposed to zero so as to communicate the end of sync for a rdev. Signed-off-by: -
Goldwyn Rodrigues authored
remove_and_add_spares() checks for all devices to activate spare. Change it to activate a specific device if a non-null rdev argument is passed. remove_and_add_spares() can be used to activate spares in slot_store() as well. For hot_remove_disk(), check if rdev->raid_disk == -1 before calling remove_and_add_spares() Signed-off-by: -
Goldwyn Rodrigues authored
When the suspended_area is deleted, the suspended processes must be woken up in order to complete their I/O. Signed-off-by: -
Guoqing Jiang authored
Previously, BITMAP_NEEDS_SYNC message is sent when the resyc aborts, but it could abort for different reasons, and not all of reasons require another node to take over the resync ownship. It is better make BITMAP_NEEDS_SYNC message only be sent when the node is leaving cluster with dirty bitmap. And we also need to ensure dlm connection is ok. Signed-off-by:
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Goldwyn Rodrigues authored
Suspending the entire device for resync could take too long. Resync in small chunks. cluster's resync window (32M) is maintained in r1conf as cluster_sync_low and cluster_sync_high and processed in raid1's sync_request(). If the current resync is outside the cluster resync window: 1. Set the cluster_sync_low to curr_resync_completed. 2. Check if the sync will fit in the new window, if not issue a wait_barrier() and set cluster_sync_low to sector_nr. 3. Set cluster_sync_high to cluster_sync_low + resync_window. 4. Send a message to all nodes so they may add it in their suspension list. bitmap_cond_end_sync is modified to allow to force a sync inorder to get the curr_resync_completed uptodate with the sector passed. Signed-off-by:
NeilBrown <neilb@suse.de>
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Goldwyn Rodrigues authored
Add BITMAP_MAJOR_CLUSTERED as 5, in order to prevent older kernels to assemble a clustered device. In order to maximize compatibility, the major version is set to BITMAP_MAJOR_CLUSTERED *only* if the bitmap is clustered. Added MD_FEATURE_CLUSTERED in order to return error for older kernels which would assemble MD even if the bitmap is corrupted. Signed-off-by:
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Goldwyn Rodrigues authored
process_suspend_info - which handles the RESYNCING request - must not reply until all writes which were initiated before the request arrived, have completed. As a by-product, all process_* functions now take mddev as their first arguement making it uniform. Signed-off-by:
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- 11 Oct, 2015 2 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull scheduler fix from Thomas Gleixner: "Fix a long standing state race in finish_task_switch()" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/core: Fix TASK_DEAD race in finish_task_switch()
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