kernel.git/drivers/md/dm-bufio.c, branch linux-5.10.y

dm bufio: subtract the number of initial sectors in dm_bufio_get_device_size

2021-03-09T10:11:12Z

commit a14e5ec66a7a66e57b24e2469f9212a78460207e upstream. dm_bufio_get_device_size returns the device size in blocks. Before returning the value, we must subtract the nubmer of starting sectors. The number of starting sectors may not be divisible by block size. Note that currently, no target is using dm_bufio_set_sector_offset and dm_bufio_get_device_size simultaneously, so this change has no effect. However, an upcoming dm-verity-fec fix needs this change. Signed-off-by: Mikulas Patocka Reviewed-by: Milan Broz Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm integrity: fix flush with external metadata device

2021-01-19T17:27:22Z

commit 9b5948267adc9e689da609eb61cf7ed49cae5fa8 upstream. With external metadata device, flush requests are not passed down to the data device. Fix this by submitting the flush request in dm_integrity_flush_buffers. In order to not degrade performance, we overlap the data device flush with the metadata device flush. Reported-by: Lukas Straub Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm bufio: do buffer cleanup from a workqueue

2020-07-20T15:17:43Z

Until now, DM bufio's waiting for IO from reclaim context in its shrinker has caused kswapd to block; which results in systemic IO stalls and even deadlock, e.g.: https://www.redhat.com/archives/dm-devel/2020-March/msg00025.html Here is Dave Chinner's problem description that motivated this fix, from: https://lore.kernel.org/linux-fsdevel/20190809215733.GZ7777@dread.disaster.area/ "Waiting for IO in kswapd reclaim context is considered harmful - kswapd context shrinker reclaim should be as non-blocking as possible, and any back-off to wait for IO to complete should be done by the high level reclaim core once it's completed an entire reclaim scan cycle of everything.... What follows from that, and is pertinent in this situation, is that if you don't block kswapd, then other reclaim contexts are not going to get stuck waiting for it regardless of the reclaim context they use." Continued elsewhere: "The only way to fix this problem once and for all is to stop using the shrinker as a mechanism to issue and wait on IO. If you need background writeback of dirty buffers, do it from a WQ_MEM_RECLAIM workqueue that isn't directly in the memory reclaim path and so can issue writeback and block safely from a GFP_KERNEL context. Kick the workqueue from the shrinker context, but get rid of the IO submission and waiting from the shrinker and all the GFP_NOFS memory reclaim recursion problems go away." As such, this commit moves buffer cleanup to a workqueue. Suggested-by: Dave Chinner Reported-by: Tahsin Erdogan Signed-off-by: Mikulas Patocka Tested-by: Gabriel Krisman Bertazi Signed-off-by: Mike Snitzer

Merge tag 'for-5.8/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2020-06-05T22:45:03Z

Pull device mapper updates from Mike Snitzer: - The largest change for this cycle is the DM zoned target's metadata version 2 feature that adds support for pairing regular block devices with a zoned device to ease the performance impact associated with finite random zones of zoned device. The changes came in three batches: the first prepared for and then added the ability to pair a single regular block device, the second was a batch of fixes to improve zoned's reclaim heuristic, and the third removed the limitation of only adding a single additional regular block device to allow many devices. Testing has shown linear scaling as more devices are added. - Add new emulated block size (ebs) target that emulates a smaller logical_block_size than a block device supports The primary use-case is to emulate "512e" devices that have 512 byte logical_block_size and 4KB physical_block_size. This is useful to some legacy applications that otherwise wouldn't be able to be used on 4K devices because they depend on issuing IO in 512 byte granularity. - Add discard interfaces to DM bufio. First consumer of the interface is the dm-ebs target that makes heavy use of dm-bufio. - Fix DM crypt's block queue_limits stacking to not truncate logic_block_size. - Add Documentation for DM integrity's status line. - Switch DMDEBUG from a compile time config option to instead use dynamic debug via pr_debug. - Fix DM multipath target's hueristic for how it manages "queue_if_no_path" state internally. DM multipath now avoids disabling "queue_if_no_path" unless it is actually needed (e.g. in response to configure timeout or explicit "fail_if_no_path" message). This fixes reports of spurious -EIO being reported back to userspace application during fault tolerance testing with an NVMe backend. Added various dynamic DMDEBUG messages to assist with debugging queue_if_no_path in the future. - Add a new DM multipath "Historical Service Time" Path Selector. - Fix DM multipath's dm_blk_ioctl() to switch paths on IO error. - Improve DM writecache target performance by using explicit cache flushing for target's single-threaded usecase and a small cleanup to remove unnecessary test in persistent_memory_claim. - Other small cleanups in DM core, dm-persistent-data, and DM integrity. * tag 'for-5.8/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (62 commits) dm crypt: avoid truncating the logical block size dm mpath: add DM device name to Failing/Reinstating path log messages dm mpath: enhance queue_if_no_path debugging dm mpath: restrict queue_if_no_path state machine dm mpath: simplify __must_push_back dm zoned: check superblock location dm zoned: prefer full zones for reclaim dm zoned: select reclaim zone based on device index dm zoned: allocate zone by device index dm zoned: support arbitrary number of devices dm zoned: move random and sequential zones into struct dmz_dev dm zoned: per-device reclaim dm zoned: add metadata pointer to struct dmz_dev dm zoned: add device pointer to struct dm_zone dm zoned: allocate temporary superblock for tertiary devices dm zoned: convert to xarray dm zoned: add a 'reserved' zone flag dm zoned: improve logging messages for reclaim dm zoned: avoid unnecessary device recalulation for secondary superblock dm zoned: add debugging message for reading superblocks ...

dm bufio: introduce forget_buffer_locked

2020-06-05T18:59:41Z

Introduce a function forget_buffer_locked that forgets a range of buffers. It is more efficient than calling forget_buffer in a loop. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: clean up rbtree block ordering

2020-06-05T18:59:41Z

dm-bufio uses unnatural ordering in the rb-tree - blocks with smaller numbers were put to the right node and blocks with bigger numbers were put to the left node. Reverse that logic so that it's natural. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: delete unused and inefficient dm_bufio_discard_buffers

2020-06-05T00:57:38Z

There is no user for this interface. If in future it is needed it can be reimplemented to walk the rbtree of buffers instead of doing block-by-block lookups. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

mm: remove the pgprot argument to __vmalloc

2020-06-02T17:59:11Z

The pgprot argument to __vmalloc is always PAGE_KERNEL now, so remove it. Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Reviewed-by: Michael Kelley [hyperv] Acked-by: Gao Xiang [erofs] Acked-by: Peter Zijlstra (Intel) Acked-by: Wei Liu Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Daniel Vetter Cc: David Airlie Cc: Greg Kroah-Hartman Cc: Haiyang Zhang Cc: Johannes Weiner Cc: "K. Y. Srinivasan" Cc: Laura Abbott Cc: Mark Rutland Cc: Minchan Kim Cc: Nitin Gupta Cc: Robin Murphy Cc: Sakari Ailus Cc: Stephen Hemminger Cc: Sumit Semwal Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Heiko Carstens Cc: Paul Mackerras Cc: Vasily Gorbik Cc: Will Deacon Link: http://lkml.kernel.org/r/20200414131348.444715-22-hch@lst.de Signed-off-by: Linus Torvalds

dm bufio: implement discard

2020-05-15T14:29:35Z

Add functions dm_bufio_issue_discard and dm_bufio_discard_buffers. dm_bufio_issue_discard sends discard request to the underlying device. dm_bufio_discard_buffers frees buffers in the range and then calls dm_bufio_issue_discard. Also, factor out block_to_sector for reuse in dm_bufio_issue_discard. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: introduce a global cache replacement

2019-09-13T21:00:21Z

This commit introduces a global cache replacement (instead of per-client cleanup). If one bufio client uses the cache heavily and another client is not using it, we want to let the first client use most of the cache. The old algorithm would partition the cache equally betwen the clients and that is sub-optimal. For cache replacement, we use the clock algorithm because it doesn't require taking any lock when the buffer is accessed. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer