kernel/linux.git/drivers/block/drbd/drbd_req.c, branch v4.4.171

block: change ->make_request_fn() and users to return a queue cookie

2015-11-07T17:40:46+00:00

No functional changes in this patch, but it prepares us for returning a more useful cookie related to the IO that was queued up. Signed-off-by: Jens Axboe Acked-by: Christoph Hellwig Acked-by: Keith Busch

block: kill merge_bvec_fn() completely

2015-08-13T18:31:57+00:00

As generic_make_request() is now able to handle arbitrarily sized bios, it's no longer necessary for each individual block driver to define its own ->merge_bvec_fn() callback. Remove every invocation completely. Cc: Jens Axboe Cc: Lars Ellenberg Cc: drbd-user@lists.linbit.com Cc: Jiri Kosina Cc: Yehuda Sadeh Cc: Sage Weil Cc: Alex Elder Cc: ceph-devel@vger.kernel.org Cc: Alasdair Kergon Cc: Mike Snitzer Cc: dm-devel@redhat.com Cc: Neil Brown Cc: linux-raid@vger.kernel.org Cc: Christoph Hellwig Cc: "Martin K. Petersen" Acked-by: NeilBrown (for the 'md' bits) Acked-by: Mike Snitzer Signed-off-by: Kent Overstreet [dpark: also remove ->merge_bvec_fn() in dm-thin as well as dm-era-target, and resolve merge conflicts] Signed-off-by: Dongsu Park Signed-off-by: Ming Lin Signed-off-by: Jens Axboe

block: make generic_make_request handle arbitrarily sized bios

2015-08-13T18:31:33+00:00

The way the block layer is currently written, it goes to great lengths to avoid having to split bios; upper layer code (such as bio_add_page()) checks what the underlying device can handle and tries to always create bios that don't need to be split. But this approach becomes unwieldy and eventually breaks down with stacked devices and devices with dynamic limits, and it adds a lot of complexity. If the block layer could split bios as needed, we could eliminate a lot of complexity elsewhere - particularly in stacked drivers. Code that creates bios can then create whatever size bios are convenient, and more importantly stacked drivers don't have to deal with both their own bio size limitations and the limitations of the (potentially multiple) devices underneath them. In the future this will let us delete merge_bvec_fn and a bunch of other code. We do this by adding calls to blk_queue_split() to the various make_request functions that need it - a few can already handle arbitrary size bios. Note that we add the call _after_ any call to blk_queue_bounce(); this means that blk_queue_split() and blk_recalc_rq_segments() don't need to be concerned with bouncing affecting segment merging. Some make_request_fn() callbacks were simple enough to audit and verify they don't need blk_queue_split() calls. The skipped ones are: * nfhd_make_request (arch/m68k/emu/nfblock.c) * axon_ram_make_request (arch/powerpc/sysdev/axonram.c) * simdisk_make_request (arch/xtensa/platforms/iss/simdisk.c) * brd_make_request (ramdisk - drivers/block/brd.c) * mtip_submit_request (drivers/block/mtip32xx/mtip32xx.c) * loop_make_request * null_queue_bio * bcache's make_request fns Some others are almost certainly safe to remove now, but will be left for future patches. Cc: Jens Axboe Cc: Christoph Hellwig Cc: Al Viro Cc: Ming Lei Cc: Neil Brown Cc: Alasdair Kergon Cc: Mike Snitzer Cc: dm-devel@redhat.com Cc: Lars Ellenberg Cc: drbd-user@lists.linbit.com Cc: Jiri Kosina Cc: Geoff Levand Cc: Jim Paris Cc: Philip Kelleher Cc: Minchan Kim Cc: Nitin Gupta Cc: Oleg Drokin Cc: Andreas Dilger Acked-by: NeilBrown (for the 'md/md.c' bits) Acked-by: Mike Snitzer Reviewed-by: Martin K. Petersen Signed-off-by: Kent Overstreet [dpark: skip more mq-based drivers, resolve merge conflicts, etc.] Signed-off-by: Dongsu Park Signed-off-by: Ming Lin Signed-off-by: Jens Axboe

block: add a bi_error field to struct bio

2015-07-29T14:55:15+00:00

Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: NeilBrown Signed-off-by: Jens Axboe

block, drbd: fix drbd_req_new() initialization

2015-03-25T02:00:16+00:00

mempool_alloc() does not support __GFP_ZERO since elements may come from memory that has already been released by mempool_free(). Remove __GFP_ZERO from mempool_alloc() in drbd_req_new() and properly initialize it to 0. Cc: Lars Ellenberg Cc: Jens Axboe Signed-off-by: David Rientjes Signed-off-by: Jens Axboe

drbd: use generic io stats accounting functions to simplify io stat accounting

2014-11-24T15:05:14+00:00

Use generic io stats accounting help functions (generic_{start,end}_io_acct) to simplify io stat accounting. Signed-off-by: Gu Zheng Signed-off-by: Jens Axboe

drbd: Fix state change in case of connection timeout

2014-11-10T16:27:41+00:00

A connection timeout affects all volumes of a resource! Under the following conditions: A resource with multiple volumes AND ko-count >=1 AND a write request triggers the timeout (ko-count * timeout) DRBD's internal state gets confused. That in turn may lead to very miss leading follow up failures. E.g. "BUG: scheduling while atomic" CC: stable@kernel.org # v3.17 Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: merge_bvec_fn: properly remap bvm->bi_bdev

2014-11-10T16:27:39+00:00

This was not noticed for many years. Affects operation if md raid is used a backing device for DRBD. CC: stable@kernel.org # v3.2+ Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: Avoid inconsistent locking warning

2014-09-11T14:41:29+00:00

request_timer_fn() takes resource->req_lock via the device and releases it via the connection. Avoid this as it is confusing static code checkers. Reported-by: "Dan Carpenter" Signed-off-by: Andreas Gruenbacher Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe

drbd: resync should only lock out specific ranges

2014-07-10T16:35:21+00:00

During resync, if we need to block some specific incoming write because of active resync requests to that same range, we potentially caused *all* new application writes (to "cold" activity log extents) to block until this one request has been processed. Improve the do_submit() logic to * grab all incoming requests to some "incoming" list * process this list - move aside requests that are blocked by resync - prepare activity log transactions, - commit transactions and submit corresponding requests - if there are remaining requests that only wait for activity log extents to become free, stop the fast path (mark activity log as "starving") - iterate until no more requests are waiting for the activity log, but all potentially remaining requests are only blocked by resync * only then grab new incoming requests That way, very busy IO on currently "hot" activity log extents cannot starve scattered IO to "cold" extents. And blocked-by-resync requests are processed once resync traffic on the affected region has ceased, without blocking anything else. The only blocking mode left is when we cannot start requests to "cold" extents because all currently "hot" extents are actually used. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg