user/sven/linux.git/fs/block_dev.c, branch v5.1.14

block: fix handling for BIO_NO_PAGE_REF

2019-05-01T14:38:47Z

Commit 399254aaf489211 ("block: add BIO_NO_PAGE_REF flag") introduces BIO_NO_PAGE_REF, and once this flag is set for one bio, all pages in the bio won't be get/put during IO. However, if one bio is submitted via __blkdev_direct_IO_simple(), even though BIO_NO_PAGE_REF is set, pages still may be put. Fixes this issue by avoiding to put pages if BIO_NO_PAGE_REF is set. Fixes: 399254aaf489211 ("block: add BIO_NO_PAGE_REF flag") Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

block: fix the return errno for direct IO

2019-04-12T03:22:21Z

If the last bio returned is not dio->bio, the status of the bio will not assigned to dio->bio if it is error. This will cause the whole IO status wrong. ksoftirqd/21-117 [021] ..s. 4017.966090: 8,0 C N 4883648 [0] -0 [018] ..s. 4017.970888: 8,0 C WS 4924800 + 1024 [0] -0 [018] ..s. 4017.970909: 8,0 D WS 4935424 + 1024 [] -0 [018] ..s. 4017.970924: 8,0 D WS 4936448 + 321 [] ksoftirqd/21-117 [021] ..s. 4017.995033: 8,0 C R 4883648 + 336 [65475] ksoftirqd/21-117 [021] d.s. 4018.001988: myprobe1: (blkdev_bio_end_io+0x0/0x168) bi_status=7 ksoftirqd/21-117 [021] d.s. 4018.001992: myprobe: (aio_complete_rw+0x0/0x148) x0=0xffff802f2595ad80 res=0x12a000 res2=0x0 We always have to assign bio->bi_status to dio->bio.bi_status because we will only check dio->bio.bi_status when we return the whole IO to the upper layer. Fixes: 542ff7bf18c6 ("block: new direct I/O implementation") Cc: stable@vger.kernel.org Cc: Christoph Hellwig Cc: Jens Axboe Reviewed-by: Ming Lei Signed-off-by: Jason Yan Signed-off-by: Jens Axboe

block: add BIO_NO_PAGE_REF flag

2019-03-18T16:44:48Z

If bio_iov_iter_get_pages() is called on an iov_iter that is flagged with NO_REF, then we don't need to add a page reference for the pages that we add. Add BIO_NO_PAGE_REF to track this in the bio, so IO completion knows not to drop a reference to these pages. Signed-off-by: Jens Axboe

block: add bio_set_polled() helper

2019-02-24T15:20:17Z

For the upcoming async polled IO, we can't sleep allocating requests. If we do, then we introduce a deadlock where the submitter already has async polled IO in-flight, but can't wait for them to complete since polled requests must be active found and reaped. Utilize the helper in the blockdev DIRECT_IO code. Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: wire up block device iopoll method

2019-02-24T15:20:17Z

Just call blk_poll on the iocb cookie, we can derive the block device from the inode trivially. Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: allow bio_for_each_segment_all() to iterate over multi-page bvec

2019-02-15T15:40:11Z

This patch introduces one extra iterator variable to bio_for_each_segment_all(), then we can allow bio_for_each_segment_all() to iterate over multi-page bvec. Given it is just one mechannical & simple change on all bio_for_each_segment_all() users, this patch does tree-wide change in one single patch, so that we can avoid to use a temporary helper for this conversion. Reviewed-by: Omar Sandoval Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

blockdev: Fix livelocks on loop device

2019-01-15T14:30:56Z

bd_set_size() updates also block device's block size. This is somewhat unexpected from its name and at this point, only blkdev_open() uses this functionality. Furthermore, this can result in changing block size under a filesystem mounted on a loop device which leads to livelocks inside __getblk_gfp() like: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10863 Comm: syz-executor0 Not tainted 4.18.0-rc5+ #151 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x50 kernel/kcov.c:106 ... Call Trace: init_page_buffers+0x3e2/0x530 fs/buffer.c:904 grow_dev_page fs/buffer.c:947 [inline] grow_buffers fs/buffer.c:1009 [inline] __getblk_slow fs/buffer.c:1036 [inline] __getblk_gfp+0x906/0xb10 fs/buffer.c:1313 __bread_gfp+0x2d/0x310 fs/buffer.c:1347 sb_bread include/linux/buffer_head.h:307 [inline] fat12_ent_bread+0x14e/0x3d0 fs/fat/fatent.c:75 fat_ent_read_block fs/fat/fatent.c:441 [inline] fat_alloc_clusters+0x8ce/0x16e0 fs/fat/fatent.c:489 fat_add_cluster+0x7a/0x150 fs/fat/inode.c:101 __fat_get_block fs/fat/inode.c:148 [inline] ... Trivial reproducer for the problem looks like: truncate -s 1G /tmp/image losetup /dev/loop0 /tmp/image mkfs.ext4 -b 1024 /dev/loop0 mount -t ext4 /dev/loop0 /mnt losetup -c /dev/loop0 l /mnt Fix the problem by moving initialization of a block device block size into a separate function and call it when needed. Thanks to Tetsuo Handa for help with debugging the problem. Reported-by: syzbot+9933e4476f365f5d5a1b@syzkaller.appspotmail.com Signed-off-by: Jan Kara Signed-off-by: Jens Axboe

block: don't use un-ordered __set_current_state(TASK_UNINTERRUPTIBLE)

2019-01-02T18:46:03Z

This mostly reverts commit 849a370016a5 ("block: avoid ordered task state change for polled IO"). It was wrongly claiming that the ordering wasn't necessary. The memory barrier _is_ necessary. If something is truly polling and not going to sleep, it's the whole state setting that is unnecessary, not the memory barrier. Whenever you set your state to a sleeping state, you absolutely need the memory barrier. Note that sometimes the memory barrier can be elsewhere. For example, the ordering might be provided by an external lock, or by setting the process state to sleeping before adding yourself to the wait queue list that is used for waking up (where the wait queue lock itself will guarantee that any wakeup will correctly see the sleeping state). But none of those cases were true here. NOTE! Some of the polling paths may indeed be able to drop the state setting entirely, at which point the memory barrier also goes away. (Also note that this doesn't revert the TASK_RUNNING cases: there is no race between a wakeup and setting the process state to TASK_RUNNING, since the end result doesn't depend on ordering). Cc: Jens Axboe Cc: Christoph Hellwig Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2018-12-29T00:55:46Z

Merge misc updates from Andrew Morton: - large KASAN update to use arm's "software tag-based mode" - a few misc things - sh updates - ocfs2 updates - just about all of MM * emailed patches from Andrew Morton : (167 commits) kernel/fork.c: mark 'stack_vm_area' with __maybe_unused memcg, oom: notify on oom killer invocation from the charge path mm, swap: fix swapoff with KSM pages include/linux/gfp.h: fix typo mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization memory_hotplug: add missing newlines to debugging output mm: remove __hugepage_set_anon_rmap() include/linux/vmstat.h: remove unused page state adjustment macro mm/page_alloc.c: allow error injection mm: migrate: drop unused argument of migrate_page_move_mapping() blkdev: avoid migration stalls for blkdev pages mm: migrate: provide buffer_migrate_page_norefs() mm: migrate: move migrate_page_lock_buffers() mm: migrate: lock buffers before migrate_page_move_mapping() mm: migration: factor out code to compute expected number of page references mm, page_alloc: enable pcpu_drain with zone capability kmemleak: add config to select auto scan mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init ...

blkdev: avoid migration stalls for blkdev pages

2018-12-28T20:11:51Z

Currently, block device pages don't provide a ->migratepage callback and thus fallback_migrate_page() is used for them. This handler cannot deal with dirty pages in async mode and also with the case a buffer head is in the LRU buffer head cache (as it has elevated b_count). Thus such page can block memory offlining. Fix the problem by using buffer_migrate_page_norefs() for migrating block device pages. That function takes care of dropping bh LRU in case migration would fail due to elevated buffer refcount to avoid stalls and can also migrate dirty pages without writing them. Link: http://lkml.kernel.org/r/20181211172143.7358-6-jack@suse.cz Signed-off-by: Jan Kara Acked-by: Mel Gorman Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds