kernel/linux.git/drivers/md/dm-thin.c, branch v4.11.5

dm thin: fix a memory leak when passing discard bio down

2017-05-20T12:49:44+00:00

commit 948f581a53b704b984aa20df009f0a2b4cf7f907 upstream. dm-thin does not free the discard_parent bio after all chained sub bios finished. The following kmemleak report could be observed after pool with discard_passdown option processes discard bios in linux v4.11-rc7. To fix this, we drop the discard_parent bio reference when its endio (passdown_endio) called. unreferenced object 0xffff8803d6b29700 (size 256): comm "kworker/u8:0", pid 30349, jiffies 4379504020 (age 143002.776s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 01 00 00 00 00 00 00 f0 00 00 00 00 00 00 00 00 ................ backtrace: [] kmemleak_alloc+0x49/0xa0 [] kmem_cache_alloc+0xb4/0x100 [] mempool_alloc_slab+0x10/0x20 [] mempool_alloc+0x55/0x150 [] bio_alloc_bioset+0xb9/0x260 [] process_prepared_discard_passdown_pt1+0x40/0x1c0 [dm_thin_pool] [] break_up_discard_bio+0x1a9/0x200 [dm_thin_pool] [] process_discard_cell_passdown+0x24/0x40 [dm_thin_pool] [] process_discard_bio+0xdd/0xf0 [dm_thin_pool] [] do_worker+0xa76/0xd50 [dm_thin_pool] [] process_one_work+0x139/0x370 [] worker_thread+0x61/0x450 [] kthread+0xd6/0xf0 [] ret_from_fork+0x3f/0x70 [] 0xffffffffffffffff Signed-off-by: Dennis Yang Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

block: Use pointer to backing_dev_info from request_queue

2017-02-02T15:20:48+00:00

We will want to have struct backing_dev_info allocated separately from struct request_queue. As the first step add pointer to backing_dev_info to request_queue and convert all users touching it. No functional changes in this patch. Reviewed-by: Christoph Hellwig Signed-off-by: Jan Kara Signed-off-by: Jens Axboe

block: add a op_is_flush helper

2017-01-27T16:01:45+00:00

This centralizes the checks for bios that needs to be go into the flush state machine. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe

block: rename bio bi_rw to bi_opf

2016-08-07T20:41:02+00:00

Since commit 63a4cc24867d, bio->bi_rw contains flags in the lower portion and the op code in the higher portions. This means that old code that relies on manually setting bi_rw is most likely going to be broken. Instead of letting that brokeness linger, rename the member, to force old and out-of-tree code to break at compile time instead of at runtime. No intended functional changes in this commit. Signed-off-by: Jens Axboe

dm thin: fix a race condition between discarding and provisioning a block

2016-07-20T16:43:35+00:00

The discard passdown was being issued after the block was unmapped, which meant the block could be reprovisioned whilst the passdown discard was still in flight. We can only identify unshared blocks (safe to do a passdown a discard to) once they're unmapped and their ref count hits zero. Block ref counts are now used to guard against concurrent allocation of these blocks that are being discarded. So now we unmap the block, issue passdown discards, and the immediately increment ref counts for regions that have been discarded via passed down (this is safe because allocation occurs within the same thread). We then decrement ref counts once the passdown discard IO is complete -- signaling these blocks may now be allocated. This fixes the potential for corruption that was reported here: https://www.redhat.com/archives/dm-devel/2016-June/msg00311.html Reported-by: Dennis Yang Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSH

2016-06-07T19:41:38+00:00

To avoid confusion between REQ_OP_FLUSH, which is handled by request_fn drivers, and upper layers requesting the block layer perform a flush sequence along with possibly a WRITE, this patch renames REQ_FLUSH to REQ_PREFLUSH. Signed-off-by: Mike Christie Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe

dm: use bio op accessors

2016-06-07T19:41:38+00:00

Separate the op from the rq_flag_bits and have dm set/get the bio using bio_set_op_attrs/bio_op. Signed-off-by: Mike Christie Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe

block discard: use bio set op accessor

2016-06-07T19:41:38+00:00

This converts the block issue discard helper and users to use the bio_set_op_attrs accessor and only pass in the operation flags like REQ_SEQURE. Signed-off-by: Mike Christie Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe

block/fs/drivers: remove rw argument from submit_bio

2016-06-07T19:41:38+00:00

This has callers of submit_bio/submit_bio_wait set the bio->bi_rw instead of passing it in. This makes that use the same as generic_make_request and how we set the other bio fields. Signed-off-by: Mike Christie Fixed up fs/ext4/crypto.c Signed-off-by: Jens Axboe

dm thin: unroll issue_discard() to create longer discard bio chains

2016-05-13T13:04:20+00:00

There is little benefit to doing this but it does structure DM thinp's code to more cleanly use the __blkdev_issue_discard() interface -- particularly in passdown_double_checking_shared_status(). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer