- 11 Oct, 2012 28 commits
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NeilBrown authored
When a RAID5 is reshaping, conf->raid_disks is increased before mddev->delta_disks becomes zero. This can result in check_reshape calling resize_stripes with a number that is too large. This particularly happens when md_check_recovery calls ->check_reshape(). If we use ->previous_raid_disks, we don't risk this. Signed-off-by:NeilBrown <neilb@suse.de>
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NeilBrown authored
If you make an array bigger but suppress resync of the new region with mdadm --grow /dev/mdX --size=max --assume-clean then stop the array before anything is written to it, the effect of the "--assume-clean" is lost and the array will resync the new space when restarted. So ensure that we update the metadata in the case. Reported-by:
Sebastian Riemer <sebastian.riemer@profitbricks.com> Signed-off-by:
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Dan Carpenter authored
Clang complains that we are assigning a variable to itself. This should be using bad_sectors like the similar earlier check does. Bug has been present since 3.1-rc1. It is minor but could conceivably cause corruption or other bad behaviour. Cc: stable@vger.kernel.org Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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NeilBrown authored
In some cases array are started in 'read-auto' state where in nothing gets written to any device until the array is written to. The purpose of this is to make accidental auto-assembly of the wrong arrays less of a risk, and to allow arrays to be started to read suspend-to-disk images without actually changing anything (as might happen if the array were dirty and a resync seemed necessary). Explicitly writing the 'sync_action' for a read-auto array currently doesn't clear the read-auto state, so the sync action doesn't happen, which can be confusing. So allow any successful write to sync_action to clear any read-auto state. Reported-by:
Alexander Kühn <alexander.kuehn@nagilum.de> Signed-off-by:
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Jianpeng Ma authored
Now that multiple threads can handle stripes, it is safer to use an atomic64_t for resync_mismatches, to avoid update races. Signed-off-by:
Jianpeng Ma <majianpeng@gmail.com> Signed-off-by:
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NeilBrown authored
to_read and to_write are part of the result of analysing a stripe before handling it. Their use is to avoid some loops and tests if the values are known to be zero. Thus it is not a problem if they are a little bit larger than they should be. So decrementing them in handle_failed_stripe serves little value, and due to races it could cause some loops to be skipped incorrectly. So remove those decrements. Reported-by:
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Alexander Lyakas authored
Signed-off-by:
Alex Lyakas <alex@zadarastorage.com> Suggested-by:
Yair Hershko <yair@zadarastorage.com> Signed-off-by:
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NeilBrown authored
The pr_debug in add_stripe_bio could race with something changing *bip, so it is best to hold the lock until after the pr_debug. Reported-by:
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NeilBrown authored
We really should hold the stripe_lock while accessing 'toread' else we could race with add_stripe_bio and corrupt a list. Reported-by:
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Shaohua Li authored
We want to avoid zero discarded dev page, because it's useless for discard. But if we don't zero it, another read/write hit such page in the cache and will get inconsistent data. To avoid zero the page, we don't set R5_UPTODATE flag after construction is done. In this way, discard write request is still issued and finished, but read will not hit the page. If the stripe gets accessed soon, we need reread the stripe, but since the chance is low, the reread isn't a big deal. Signed-off-by:
Shaohua Li <shli@fusionio.com> Signed-off-by:
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Shaohua Li authored
Discard for raid4/5/6 has limitation. If discard request size is small, we do discard for one disk, but we need calculate parity and write parity disk. To correctly calculate parity, zero_after_discard must be guaranteed. Even it's true, we need do discard for one disk but write another disks, which makes the parity disks wear out fast. This doesn't make sense. So an efficient discard for raid4/5/6 should discard all data disks and parity disks, which requires the write pattern to be (A, A+chunk_size, A+chunk_size*2...). If A's size is smaller than chunk_size, such pattern is almost impossible in practice. So in this patch, I only handle the case that A's size equals to chunk_size. That is discard request should be aligned to stripe size and its size is multiple of stripe size. Since we can only handle request with specific alignment and size (or part of the request fitting stripes), we can't guarantee zero_after_discard even zero_after_discard is true in low level drives. The block layer doesn't send down correctly aligned requests even correct discard alignment is set, so I must filter out. For raid4/5/6 parity calculation, if data is 0, parity is 0. So if zero_after_discard is true for all disks, data is consistent after discard. Otherwise, data might be lost. Let's consider a scenario: discard a stripe, write data to one disk and write parity disk. The stripe could be still inconsistent till then depending on using data from other data disks or parity disks to calculate new parity. If the disk is broken, we can't restore it. So in this patch, we only enable discard support if all disks have zero_after_discard. If discard fails in one disk, we face the similar inconsistent issue above. The patch will make discard follow the same path as normal write request. If discard fails, a resync will be scheduled to make the data consistent. This isn't good to have extra writes, but data consistency is important. If a subsequent read/write request hits raid5 cache of a discarded stripe, the discarded dev page should have zero filled, so the data is consistent. This patch will always zero dev page for discarded request stripe. This isn't optimal because discard request doesn't need such payload. Next patch will avoid it. Signed-off-by:
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Jianpeng Ma authored
Signed-off-by:
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NeilBrown authored
When we get a read error, we arrange for raid1d to handle it. Currently we release the reference on the device. This can result in conf->mirrors[read_disk].rdev being NULL in fix_read_error, if the device happens to get removed before the read error is handled. So instead keep the reference until the read error has been fully handled. Reported-by:
hank <pyu@redhat.com> Signed-off-by:
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Michael Wang authored
This patch replaces list_for_each_continue_rcu() with list_for_each_entry_continue_rcu() to save a few lines of code and allow removing list_for_each_continue_rcu(). Reviewed-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by:
Michael Wang <wangyun@linux.vnet.ibm.com> Signed-off-by:
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Jan Beulich authored
Allow particularly do_xor_speed() to be discarded post-init. Signed-off-by:
Jan Beulich <jbeulich@suse.com> Signed-off-by:
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Jonathan Brassow authored
There are two table arguments that can be given to a DM RAID target that control whether the array is forced to (re)synchronize or skip initialization: "sync" and "nosync". When "sync" is given, we set mddev->recovery_cp to 0 in order to cause the device to resynchronize. This is insufficient if there is a bitmap in use, because the array will simply look at the bitmap and see that there is no recovery necessary. The fix is to skip over the loading of the superblocks when "sync" is given, causing new superblocks to be written that will force the array to go through initialization (i.e. synchronization). Signed-off-by:
Jonathan Brassow <jbrassow@redhat.com> Signed-off-by:
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Jonathan Brassow authored
DM RAID: Fix comparison of index and quantity for "rebuild" parameter The "rebuild" parameter takes an index argument that starts counting from zero. The conditional used to validate the index was using '>' rather than '>=', leaving the door open for an index value that would be 1 too large. Reported-by:
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Jonathan Brassow authored
DM RAID: Add code to validate replacement slots for RAID10 arrays RAID10 can handle 'copies - 1' failures for each mirror group. This code ensures the user has provided a valid array - one whose devices specified for rebuild do not exceed the amount of redundancy available. Signed-off-by:
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Jonathan Brassow authored
DM RAID: Move chunk of code to it's own function The code that checks whether device replacements/rebuilds are possible given a specific RAID type is moved to it's own function. It will further expand when the code to check RAID10 is added. A separate function makes it easier to read. Signed-off-by:
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Jonathan Brassow authored
MD RAID10: Fix a couple potential kernel panics if RAID10 is used by dm-raid When device-mapper uses the RAID10 personality through dm-raid.c, there is no 'gendisk' structure in mddev and some sysfs information is also not populated. This patch avoids touching those non-existent structures. Signed-off-by:
Jonathan Brassow <jbrassow@rehdat.com> Signed-off-by:
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NeilBrown authored
Some ioctls don't need to take the mutex and doing so can cause a delay as it is held during super-block update. So move those ioctls out of the mutex and rely on rcu locking to ensure we don't access stale data. Signed-off-by: -
Shaohua Li authored
Change the thread parameter, so the thread can carry extra info. Next patch will use it. Signed-off-by:
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NeilBrown authored
queuing writes to the md thread means that all requests go through the one processor which may not be able to keep up with very high request rates. So use the plugging infrastructure to submit all requests on unplug. If a 'schedule' is needed, we fall back on the old approach of handing the requests to the thread for it to handle. This is nearly identical to a recent patch which provided similar functionality to RAID1. Signed-off-by: -
Shaohua Li authored
This makes md raid 10 support TRIM. If one disk supports discard and another not, or one has discard_zero_data and another not, there could be inconsistent between data from such disks. But this should not matter, discarded data is useless. This will add extra copy in rebuild though. Signed-off-by:
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Shaohua Li authored
This makes md raid 1 support TRIM. If one disk supports discard and another not, or one has discard_zero_data and another not, there could be inconsistent between data from such disks. But this should not matter, discarded data is useless. This will add extra copy in rebuild though. Signed-off-by:
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Shaohua Li authored
This makes md raid 0 support TRIM. Signed-off-by:
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Shaohua Li authored
This makes md linear support TRIM. Signed-off-by:
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Denis Efremov authored
According to the comment in linear_stop function rcu_dereference in linear_start and linear_stop functions occurs under reconfig_mutex. The patch represents this agreement in code and prevents lockdep complaint. Found by Linux Driver Verification project (linuxtesting.org) Signed-off-by:
Denis Efremov <yefremov.denis@gmail.com> Signed-off-by:
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- 28 Sep, 2012 2 commits
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Shaohua Li authored
discard bio hasn't data attached. We hit a BUG_ON with such bio. This makes bio_split works for such bio. Signed-off-by:
Jens Axboe <axboe@kernel.dk>
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Maxim Levitsky authored
Replace 'while' with 'for' as suggested by Tejun Heo Signed-off-by:
Maxim Levitsky <maximlevitsky@gmail.com> Signed-off-by:
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- 27 Sep, 2012 2 commits
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Maxim Levitsky authored
Useful helper to know the number of entries in scatterlist. Signed-off-by:
Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by:
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Jens Axboe authored
We get the following export error on the include file: usr/include/linux/fs.h:13: included file 'linux/percpu-rwsem.h' is not exported Move the include inside the __KERNEL__ section. Reported-by:
Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
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- 26 Sep, 2012 4 commits
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Mikulas Patocka authored
One more patch for this thing, fixing some typos in the documentation. Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:
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Fengguang Wu authored
blkdev_mmap() isn't used outside of fs/block_dev.c, mark it as static. Reported-by:
Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:
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Mikulas Patocka authored
This avoids cache line bouncing when many processes lock the semaphore for read. New percpu lock implementation The lock consists of an array of percpu unsigned integers, a boolean variable and a mutex. When we take the lock for read, we enter rcu read section, check for a "locked" variable. If it is false, we increase a percpu counter on the current cpu and exit the rcu section. If "locked" is true, we exit the rcu section, take the mutex and drop it (this waits until a writer finished) and retry. Unlocking for read just decreases percpu variable. Note that we can unlock on a difference cpu than where we locked, in this case the counter underflows. The sum of all percpu counters represents the number of processes that hold the lock for read. When we need to lock for write, we take the mutex, set "locked" variable to true and synchronize rcu. Since RCU has been synchronized, no processes can create new read locks. We wait until the sum of percpu counters is zero - when it is, there are no readers in the critical section. Signed-off-by:
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Mikulas Patocka authored
The kernel may crash when block size is changed and I/O is issued simultaneously. Because some subsystems (udev or lvm) may read any block device anytime, the bug actually puts any code that changes a block device size in jeopardy. The crash can be reproduced if you place "msleep(1000)" to blkdev_get_blocks just before "bh->b_size = max_blocks << inode->i_blkbits;". Then, run "dd if=/dev/ram0 of=/dev/null bs=4k count=1 iflag=direct" While it is waiting in msleep, run "blockdev --setbsz 2048 /dev/ram0" You get a BUG. The direct and non-direct I/O is written with the assumption that block size does not change. It doesn't seem practical to fix these crashes one-by-one there may be many crash possibilities when block size changes at a certain place and it is impossible to find them all and verify the code. This patch introduces a new rw-lock bd_block_size_semaphore. The lock is taken for read during I/O. It is taken for write when changing block size. Consequently, block size can't be changed while I/O is being submitted. For asynchronous I/O, the patch only prevents block size change while the I/O is being submitted. The block size can change when the I/O is in progress or when the I/O is being finished. This is acceptable because there are no accesses to block size when asynchronous I/O is being finished. The patch prevents block size changing while the device is mapped with mmap. Signed-off-by:
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- 21 Sep, 2012 2 commits
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Tejun Heo authored
A queue newly allocated with blk_alloc_queue_node() has only QUEUE_FLAG_BYPASS set. For request-based drivers, blk_init_allocated_queue() is called and q->queue_flags is overwritten with QUEUE_FLAG_DEFAULT which doesn't include BYPASS even though the initial bypass is still in effect. In blk_init_allocated_queue(), or QUEUE_FLAG_DEFAULT to q->queue_flags instead of overwriting. Signed-off-by:
Vivek Goyal <vgoyal@redhat.com> Signed-off-by:
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Tejun Heo authored
block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue() b82d4b19 ("blkcg: make request_queue bypassing on allocation") made request_queues bypassed on allocation to avoid switching on and off bypass mode on a queue being initialized. Some drivers allocate and then destroy a lot of queues without fully initializing them and incurring bypass latency overhead on each of them could add upto significant overhead. Unfortunately, blk_init_allocated_queue() is never used by queues of bio-based drivers, which means that all bio-based driver queues are in bypass mode even after initialization and registration complete successfully. Due to the limited way request_queues are used by bio drivers, this problem is hidden pretty well but it shows up when blk-throttle is used in combination with a bio-based driver. Trying to configure (echoing to cgroupfs file) blk-throttle for a bio-based driver hangs indefinitely in blkg_conf_prep() waiting for bypass mode to end. This patch moves the initial blk_queue_bypass_end() call from blk_init_allocated_queue() to blk_register_queue() which is called for any userland-visible queues regardless of its type. I believe this is correct because I don't think there is any block driver which needs or wants working elevator and blk-cgroup on a queue which isn't visible to userland. If there are such users, we need a different solution. Signed-off-by:
Joseph Glanville <joseph.glanville@orionvm.com.au> Cc: stable@vger.kernel.org Acked-by:
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- 20 Sep, 2012 2 commits
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Martin K. Petersen authored
Introduce a BLKZEROOUT ioctl which can be used to clear block ranges by way of blkdev_issue_zeroout(). Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com> Acked-by:
Mike Snitzer <snitzer@redhat.com> Signed-off-by:
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Martin K. Petersen authored
If the device supports WRITE SAME, use that to optimize zeroing of blocks. If the device does not support WRITE SAME or if the operation fails, fall back to writing zeroes the old-fashioned way. Signed-off-by:
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