| Message ID | 1447984177-26795-1-git-send-email-bo.li.liu@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Nov 19, 2015 at 05:49:37PM -0800, Liu Bo wrote: > while xfstesting, this bug[1] is spotted by both btrfs/061 and btrfs/063, > so those sub-stripe writes are gatherred into plug callback list and > hopefully we can have a full stripe writes. > > However, while processing these plugged callbacks, it's within an atomic > context which is provided by blk_sq_make_request() because of a get_cpu() > in blk_mq_get_ctx(). > > This changes to always use btrfs_rmw_helper to complete the pending writes. > Thanks Liu, but MD raid has the same troubles, we're not atomic in our unplugs. Jens? > [1]: > > BUG: sleeping function called from invalid context at mm/page_alloc.c:3190 > in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u16:0 > 3 locks held by kworker/u16:0/6: > #0: ("writeback"){++++.+}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 > #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 > #2: (&type->s_umount_key#44){+++++.}, at: [<ffffffff811e6805>] trylock_super+0x25/0x60 > CPU: 5 PID: 6 Comm: kworker/u16:0 Tainted: G OE 4.3.0+ #3 > Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011 > Workqueue: writeback wb_workfn (flush-btrfs-108) > ffffffff81a3abab ffff88042e282ba8 ffffffff8130191b ffffffff81a3abab > 0000000000000c76 ffff88042e282ba8 ffff88042e27c180 ffff88042e282bd8 > ffffffff8108ed95 ffff880400000004 0000000000000000 0000000000000c76 > Call Trace: > [<ffffffff8130191b>] dump_stack+0x4f/0x74 > [<ffffffff8108ed95>] ___might_sleep+0x185/0x240 > [<ffffffff8108eea2>] __might_sleep+0x52/0x90 > [<ffffffff811817e8>] __alloc_pages_nodemask+0x268/0x410 > [<ffffffff8109a43c>] ? sched_clock_local+0x1c/0x90 > [<ffffffff8109a6d1>] ? local_clock+0x21/0x40 > [<ffffffff810b9eb0>] ? __lock_release+0x420/0x510 > [<ffffffff810b534c>] ? __lock_acquired+0x16c/0x3c0 > [<ffffffff811ca265>] alloc_pages_current+0xc5/0x210 > [<ffffffffa0577105>] ? rbio_is_full+0x55/0x70 [btrfs] > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > [<ffffffff81666d50>] ? _raw_spin_unlock_irqrestore+0x40/0x60 > [<ffffffffa0578c0a>] full_stripe_write+0x5a/0xc0 [btrfs] > [<ffffffffa0578ca9>] __raid56_parity_write+0x39/0x60 [btrfs] > [<ffffffffa0578deb>] run_plug+0x11b/0x140 [btrfs] > [<ffffffffa0578e33>] btrfs_raid_unplug+0x23/0x70 [btrfs] > [<ffffffff812d36c2>] blk_flush_plug_list+0x82/0x1f0 > [<ffffffff812e0349>] blk_sq_make_request+0x1f9/0x740 > [<ffffffff812ceba2>] ? generic_make_request_checks+0x222/0x7c0 > [<ffffffff812cf264>] ? blk_queue_enter+0x124/0x310 > [<ffffffff812cf1d2>] ? blk_queue_enter+0x92/0x310 > [<ffffffff812d0ae2>] generic_make_request+0x172/0x2c0 > [<ffffffff812d0ad4>] ? generic_make_request+0x164/0x2c0 > [<ffffffff812d0ca0>] submit_bio+0x70/0x140 > [<ffffffffa0577b29>] ? rbio_add_io_page+0x99/0x150 [btrfs] > [<ffffffffa0578a89>] finish_rmw+0x4d9/0x600 [btrfs] > [<ffffffffa0578c4c>] full_stripe_write+0x9c/0xc0 [btrfs] > [<ffffffffa057ab7f>] raid56_parity_write+0xef/0x160 [btrfs] > [<ffffffffa052bd83>] btrfs_map_bio+0xe3/0x2d0 [btrfs] > [<ffffffffa04fbd6d>] btrfs_submit_bio_hook+0x8d/0x1d0 [btrfs] > [<ffffffffa05173c4>] submit_one_bio+0x74/0xb0 [btrfs] > [<ffffffffa0517f55>] submit_extent_page+0xe5/0x1c0 [btrfs] > [<ffffffffa0519b18>] __extent_writepage_io+0x408/0x4c0 [btrfs] > [<ffffffffa05179c0>] ? alloc_dummy_extent_buffer+0x140/0x140 [btrfs] > [<ffffffffa051dc88>] __extent_writepage+0x218/0x3a0 [btrfs] > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > [<ffffffffa051e2c9>] extent_write_cache_pages.clone.0+0x2f9/0x400 [btrfs] > [<ffffffffa051e422>] extent_writepages+0x52/0x70 [btrfs] > [<ffffffffa05001f0>] ? btrfs_set_inode_index+0x70/0x70 [btrfs] > [<ffffffffa04fcc17>] btrfs_writepages+0x27/0x30 [btrfs] > [<ffffffff81184df3>] do_writepages+0x23/0x40 > [<ffffffff81212229>] __writeback_single_inode+0x89/0x4d0 > [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 > [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 > [<ffffffff8121295f>] ? writeback_sb_inodes+0x15f/0x480 > [<ffffffff81212ad2>] writeback_sb_inodes+0x2d2/0x480 > [<ffffffff810b1397>] ? down_read_trylock+0x57/0x60 > [<ffffffff811e6805>] ? trylock_super+0x25/0x60 > [<ffffffff810d629f>] ? rcu_read_lock_sched_held+0x4f/0x90 > [<ffffffff81212d0c>] __writeback_inodes_wb+0x8c/0xc0 > [<ffffffff812130b5>] wb_writeback+0x2b5/0x500 > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > [<ffffffff810660a8>] ? __local_bh_enable_ip+0x68/0xc0 > [<ffffffff81213362>] ? wb_do_writeback+0x62/0x310 > [<ffffffff812133c1>] wb_do_writeback+0xc1/0x310 > [<ffffffff8107c3d9>] ? set_worker_desc+0x79/0x90 > [<ffffffff81213842>] wb_workfn+0x92/0x330 > [<ffffffff8107f133>] process_one_work+0x223/0x730 > [<ffffffff8107f083>] ? process_one_work+0x173/0x730 > [<ffffffff8108035f>] ? worker_thread+0x18f/0x430 > [<ffffffff810802ed>] worker_thread+0x11d/0x430 > [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 > [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 > [<ffffffff810858df>] kthread+0xef/0x110 > [<ffffffff8108f74e>] ? schedule_tail+0x1e/0xd0 > [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 > [<ffffffff816673bf>] ret_from_fork+0x3f/0x70 > [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 20, 2015 at 08:13:58AM -0500, Chris Mason wrote: > On Thu, Nov 19, 2015 at 05:49:37PM -0800, Liu Bo wrote: > > while xfstesting, this bug[1] is spotted by both btrfs/061 and btrfs/063, > > so those sub-stripe writes are gatherred into plug callback list and > > hopefully we can have a full stripe writes. > > > > However, while processing these plugged callbacks, it's within an atomic > > context which is provided by blk_sq_make_request() because of a get_cpu() > > in blk_mq_get_ctx(). > > > > This changes to always use btrfs_rmw_helper to complete the pending writes. > > > > Thanks Liu, but MD raid has the same troubles, we're not atomic in our unplugs. Yeah, MD also does, but I don't see a way to change mq code at this stage.. Thanks, -liubo > > Jens? > > > [1]: > > > > BUG: sleeping function called from invalid context at mm/page_alloc.c:3190 > > in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u16:0 > > 3 locks held by kworker/u16:0/6: > > #0: ("writeback"){++++.+}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 > > #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 > > #2: (&type->s_umount_key#44){+++++.}, at: [<ffffffff811e6805>] trylock_super+0x25/0x60 > > CPU: 5 PID: 6 Comm: kworker/u16:0 Tainted: G OE 4.3.0+ #3 > > Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011 > > Workqueue: writeback wb_workfn (flush-btrfs-108) > > ffffffff81a3abab ffff88042e282ba8 ffffffff8130191b ffffffff81a3abab > > 0000000000000c76 ffff88042e282ba8 ffff88042e27c180 ffff88042e282bd8 > > ffffffff8108ed95 ffff880400000004 0000000000000000 0000000000000c76 > > Call Trace: > > [<ffffffff8130191b>] dump_stack+0x4f/0x74 > > [<ffffffff8108ed95>] ___might_sleep+0x185/0x240 > > [<ffffffff8108eea2>] __might_sleep+0x52/0x90 > > [<ffffffff811817e8>] __alloc_pages_nodemask+0x268/0x410 > > [<ffffffff8109a43c>] ? sched_clock_local+0x1c/0x90 > > [<ffffffff8109a6d1>] ? local_clock+0x21/0x40 > > [<ffffffff810b9eb0>] ? __lock_release+0x420/0x510 > > [<ffffffff810b534c>] ? __lock_acquired+0x16c/0x3c0 > > [<ffffffff811ca265>] alloc_pages_current+0xc5/0x210 > > [<ffffffffa0577105>] ? rbio_is_full+0x55/0x70 [btrfs] > > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > > [<ffffffff81666d50>] ? _raw_spin_unlock_irqrestore+0x40/0x60 > > [<ffffffffa0578c0a>] full_stripe_write+0x5a/0xc0 [btrfs] > > [<ffffffffa0578ca9>] __raid56_parity_write+0x39/0x60 [btrfs] > > [<ffffffffa0578deb>] run_plug+0x11b/0x140 [btrfs] > > [<ffffffffa0578e33>] btrfs_raid_unplug+0x23/0x70 [btrfs] > > [<ffffffff812d36c2>] blk_flush_plug_list+0x82/0x1f0 > > [<ffffffff812e0349>] blk_sq_make_request+0x1f9/0x740 > > [<ffffffff812ceba2>] ? generic_make_request_checks+0x222/0x7c0 > > [<ffffffff812cf264>] ? blk_queue_enter+0x124/0x310 > > [<ffffffff812cf1d2>] ? blk_queue_enter+0x92/0x310 > > [<ffffffff812d0ae2>] generic_make_request+0x172/0x2c0 > > [<ffffffff812d0ad4>] ? generic_make_request+0x164/0x2c0 > > [<ffffffff812d0ca0>] submit_bio+0x70/0x140 > > [<ffffffffa0577b29>] ? rbio_add_io_page+0x99/0x150 [btrfs] > > [<ffffffffa0578a89>] finish_rmw+0x4d9/0x600 [btrfs] > > [<ffffffffa0578c4c>] full_stripe_write+0x9c/0xc0 [btrfs] > > [<ffffffffa057ab7f>] raid56_parity_write+0xef/0x160 [btrfs] > > [<ffffffffa052bd83>] btrfs_map_bio+0xe3/0x2d0 [btrfs] > > [<ffffffffa04fbd6d>] btrfs_submit_bio_hook+0x8d/0x1d0 [btrfs] > > [<ffffffffa05173c4>] submit_one_bio+0x74/0xb0 [btrfs] > > [<ffffffffa0517f55>] submit_extent_page+0xe5/0x1c0 [btrfs] > > [<ffffffffa0519b18>] __extent_writepage_io+0x408/0x4c0 [btrfs] > > [<ffffffffa05179c0>] ? alloc_dummy_extent_buffer+0x140/0x140 [btrfs] > > [<ffffffffa051dc88>] __extent_writepage+0x218/0x3a0 [btrfs] > > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > > [<ffffffffa051e2c9>] extent_write_cache_pages.clone.0+0x2f9/0x400 [btrfs] > > [<ffffffffa051e422>] extent_writepages+0x52/0x70 [btrfs] > > [<ffffffffa05001f0>] ? btrfs_set_inode_index+0x70/0x70 [btrfs] > > [<ffffffffa04fcc17>] btrfs_writepages+0x27/0x30 [btrfs] > > [<ffffffff81184df3>] do_writepages+0x23/0x40 > > [<ffffffff81212229>] __writeback_single_inode+0x89/0x4d0 > > [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 > > [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 > > [<ffffffff8121295f>] ? writeback_sb_inodes+0x15f/0x480 > > [<ffffffff81212ad2>] writeback_sb_inodes+0x2d2/0x480 > > [<ffffffff810b1397>] ? down_read_trylock+0x57/0x60 > > [<ffffffff811e6805>] ? trylock_super+0x25/0x60 > > [<ffffffff810d629f>] ? rcu_read_lock_sched_held+0x4f/0x90 > > [<ffffffff81212d0c>] __writeback_inodes_wb+0x8c/0xc0 > > [<ffffffff812130b5>] wb_writeback+0x2b5/0x500 > > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > > [<ffffffff810660a8>] ? __local_bh_enable_ip+0x68/0xc0 > > [<ffffffff81213362>] ? wb_do_writeback+0x62/0x310 > > [<ffffffff812133c1>] wb_do_writeback+0xc1/0x310 > > [<ffffffff8107c3d9>] ? set_worker_desc+0x79/0x90 > > [<ffffffff81213842>] wb_workfn+0x92/0x330 > > [<ffffffff8107f133>] process_one_work+0x223/0x730 > > [<ffffffff8107f083>] ? process_one_work+0x173/0x730 > > [<ffffffff8108035f>] ? worker_thread+0x18f/0x430 > > [<ffffffff810802ed>] worker_thread+0x11d/0x430 > > [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 > > [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 > > [<ffffffff810858df>] kthread+0xef/0x110 > > [<ffffffff8108f74e>] ? schedule_tail+0x1e/0xd0 > > [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 > > [<ffffffff816673bf>] ret_from_fork+0x3f/0x70 > > [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 20, 2015 at 09:57:49AM -0800, Liu Bo wrote: > On Fri, Nov 20, 2015 at 08:13:58AM -0500, Chris Mason wrote: > > On Thu, Nov 19, 2015 at 05:49:37PM -0800, Liu Bo wrote: > > > while xfstesting, this bug[1] is spotted by both btrfs/061 and btrfs/063, > > > so those sub-stripe writes are gatherred into plug callback list and > > > hopefully we can have a full stripe writes. > > > > > > However, while processing these plugged callbacks, it's within an atomic > > > context which is provided by blk_sq_make_request() because of a get_cpu() > > > in blk_mq_get_ctx(). > > > > > > This changes to always use btrfs_rmw_helper to complete the pending writes. > > > > > > > Thanks Liu, but MD raid has the same troubles, we're not atomic in our unplugs. > > Yeah, MD also does, but I don't see a way to change mq code at this > stage.. Correct it: MD raid5_unplug runs stripes inside a pair of spinlock (conf->device_lock) and moreover, those writes will be forwarded to raid5d to finish the job. So md raid can run fine within atomic context. Thanks, -liubo > > Thanks, > > -liubo > > > > > Jens? > > > > > [1]: > > > > > > BUG: sleeping function called from invalid context at mm/page_alloc.c:3190 > > > in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u16:0 > > > 3 locks held by kworker/u16:0/6: > > > #0: ("writeback"){++++.+}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 > > > #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 > > > #2: (&type->s_umount_key#44){+++++.}, at: [<ffffffff811e6805>] trylock_super+0x25/0x60 > > > CPU: 5 PID: 6 Comm: kworker/u16:0 Tainted: G OE 4.3.0+ #3 > > > Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011 > > > Workqueue: writeback wb_workfn (flush-btrfs-108) > > > ffffffff81a3abab ffff88042e282ba8 ffffffff8130191b ffffffff81a3abab > > > 0000000000000c76 ffff88042e282ba8 ffff88042e27c180 ffff88042e282bd8 > > > ffffffff8108ed95 ffff880400000004 0000000000000000 0000000000000c76 > > > Call Trace: > > > [<ffffffff8130191b>] dump_stack+0x4f/0x74 > > > [<ffffffff8108ed95>] ___might_sleep+0x185/0x240 > > > [<ffffffff8108eea2>] __might_sleep+0x52/0x90 > > > [<ffffffff811817e8>] __alloc_pages_nodemask+0x268/0x410 > > > [<ffffffff8109a43c>] ? sched_clock_local+0x1c/0x90 > > > [<ffffffff8109a6d1>] ? local_clock+0x21/0x40 > > > [<ffffffff810b9eb0>] ? __lock_release+0x420/0x510 > > > [<ffffffff810b534c>] ? __lock_acquired+0x16c/0x3c0 > > > [<ffffffff811ca265>] alloc_pages_current+0xc5/0x210 > > > [<ffffffffa0577105>] ? rbio_is_full+0x55/0x70 [btrfs] > > > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > > > [<ffffffff81666d50>] ? _raw_spin_unlock_irqrestore+0x40/0x60 > > > [<ffffffffa0578c0a>] full_stripe_write+0x5a/0xc0 [btrfs] > > > [<ffffffffa0578ca9>] __raid56_parity_write+0x39/0x60 [btrfs] > > > [<ffffffffa0578deb>] run_plug+0x11b/0x140 [btrfs] > > > [<ffffffffa0578e33>] btrfs_raid_unplug+0x23/0x70 [btrfs] > > > [<ffffffff812d36c2>] blk_flush_plug_list+0x82/0x1f0 > > > [<ffffffff812e0349>] blk_sq_make_request+0x1f9/0x740 > > > [<ffffffff812ceba2>] ? generic_make_request_checks+0x222/0x7c0 > > > [<ffffffff812cf264>] ? blk_queue_enter+0x124/0x310 > > > [<ffffffff812cf1d2>] ? blk_queue_enter+0x92/0x310 > > > [<ffffffff812d0ae2>] generic_make_request+0x172/0x2c0 > > > [<ffffffff812d0ad4>] ? generic_make_request+0x164/0x2c0 > > > [<ffffffff812d0ca0>] submit_bio+0x70/0x140 > > > [<ffffffffa0577b29>] ? rbio_add_io_page+0x99/0x150 [btrfs] > > > [<ffffffffa0578a89>] finish_rmw+0x4d9/0x600 [btrfs] > > > [<ffffffffa0578c4c>] full_stripe_write+0x9c/0xc0 [btrfs] > > > [<ffffffffa057ab7f>] raid56_parity_write+0xef/0x160 [btrfs] > > > [<ffffffffa052bd83>] btrfs_map_bio+0xe3/0x2d0 [btrfs] > > > [<ffffffffa04fbd6d>] btrfs_submit_bio_hook+0x8d/0x1d0 [btrfs] > > > [<ffffffffa05173c4>] submit_one_bio+0x74/0xb0 [btrfs] > > > [<ffffffffa0517f55>] submit_extent_page+0xe5/0x1c0 [btrfs] > > > [<ffffffffa0519b18>] __extent_writepage_io+0x408/0x4c0 [btrfs] > > > [<ffffffffa05179c0>] ? alloc_dummy_extent_buffer+0x140/0x140 [btrfs] > > > [<ffffffffa051dc88>] __extent_writepage+0x218/0x3a0 [btrfs] > > > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > > > [<ffffffffa051e2c9>] extent_write_cache_pages.clone.0+0x2f9/0x400 [btrfs] > > > [<ffffffffa051e422>] extent_writepages+0x52/0x70 [btrfs] > > > [<ffffffffa05001f0>] ? btrfs_set_inode_index+0x70/0x70 [btrfs] > > > [<ffffffffa04fcc17>] btrfs_writepages+0x27/0x30 [btrfs] > > > [<ffffffff81184df3>] do_writepages+0x23/0x40 > > > [<ffffffff81212229>] __writeback_single_inode+0x89/0x4d0 > > > [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 > > > [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 > > > [<ffffffff8121295f>] ? writeback_sb_inodes+0x15f/0x480 > > > [<ffffffff81212ad2>] writeback_sb_inodes+0x2d2/0x480 > > > [<ffffffff810b1397>] ? down_read_trylock+0x57/0x60 > > > [<ffffffff811e6805>] ? trylock_super+0x25/0x60 > > > [<ffffffff810d629f>] ? rcu_read_lock_sched_held+0x4f/0x90 > > > [<ffffffff81212d0c>] __writeback_inodes_wb+0x8c/0xc0 > > > [<ffffffff812130b5>] wb_writeback+0x2b5/0x500 > > > [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 > > > [<ffffffff810660a8>] ? __local_bh_enable_ip+0x68/0xc0 > > > [<ffffffff81213362>] ? wb_do_writeback+0x62/0x310 > > > [<ffffffff812133c1>] wb_do_writeback+0xc1/0x310 > > > [<ffffffff8107c3d9>] ? set_worker_desc+0x79/0x90 > > > [<ffffffff81213842>] wb_workfn+0x92/0x330 > > > [<ffffffff8107f133>] process_one_work+0x223/0x730 > > > [<ffffffff8107f083>] ? process_one_work+0x173/0x730 > > > [<ffffffff8108035f>] ? worker_thread+0x18f/0x430 > > > [<ffffffff810802ed>] worker_thread+0x11d/0x430 > > > [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 > > > [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 > > > [<ffffffff810858df>] kthread+0xef/0x110 > > > [<ffffffff8108f74e>] ? schedule_tail+0x1e/0xd0 > > > [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 > > > [<ffffffff816673bf>] ret_from_fork+0x3f/0x70 > > > [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 20, 2015 at 12:06:33PM -0800, Liu Bo wrote: > On Fri, Nov 20, 2015 at 09:57:49AM -0800, Liu Bo wrote: > > On Fri, Nov 20, 2015 at 08:13:58AM -0500, Chris Mason wrote: > > > On Thu, Nov 19, 2015 at 05:49:37PM -0800, Liu Bo wrote: > > > > while xfstesting, this bug[1] is spotted by both btrfs/061 and btrfs/063, > > > > so those sub-stripe writes are gatherred into plug callback list and > > > > hopefully we can have a full stripe writes. > > > > > > > > However, while processing these plugged callbacks, it's within an atomic > > > > context which is provided by blk_sq_make_request() because of a get_cpu() > > > > in blk_mq_get_ctx(). > > > > > > > > This changes to always use btrfs_rmw_helper to complete the pending writes. > > > > > > > > > > Thanks Liu, but MD raid has the same troubles, we're not atomic in our unplugs. > > > > Yeah, MD also does, but I don't see a way to change mq code at this > > stage.. > > Correct it: MD raid5_unplug runs stripes inside a pair of spinlock (conf->device_lock) and moreover, those writes will be forwarded to raid5d to finish the job. > > So md raid can run fine within atomic context. Check MD raid10 -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c index 1a33d3e..03fcf32 100644 --- a/fs/btrfs/raid56.c +++ b/fs/btrfs/raid56.c @@ -1731,14 +1731,11 @@ static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule) struct btrfs_plug_cb *plug; plug = container_of(cb, struct btrfs_plug_cb, cb); - if (from_schedule) { - btrfs_init_work(&plug->work, btrfs_rmw_helper, - unplug_work, NULL, NULL); - btrfs_queue_work(plug->info->rmw_workers, - &plug->work); - return; - } - run_plug(plug); + btrfs_init_work(&plug->work, btrfs_rmw_helper, + unplug_work, NULL, NULL); + btrfs_queue_work(plug->info->rmw_workers, + &plug->work); + return; } /*
while xfstesting, this bug[1] is spotted by both btrfs/061 and btrfs/063, so those sub-stripe writes are gatherred into plug callback list and hopefully we can have a full stripe writes. However, while processing these plugged callbacks, it's within an atomic context which is provided by blk_sq_make_request() because of a get_cpu() in blk_mq_get_ctx(). This changes to always use btrfs_rmw_helper to complete the pending writes. [1]: BUG: sleeping function called from invalid context at mm/page_alloc.c:3190 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u16:0 3 locks held by kworker/u16:0/6: #0: ("writeback"){++++.+}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730 #2: (&type->s_umount_key#44){+++++.}, at: [<ffffffff811e6805>] trylock_super+0x25/0x60 CPU: 5 PID: 6 Comm: kworker/u16:0 Tainted: G OE 4.3.0+ #3 Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011 Workqueue: writeback wb_workfn (flush-btrfs-108) ffffffff81a3abab ffff88042e282ba8 ffffffff8130191b ffffffff81a3abab 0000000000000c76 ffff88042e282ba8 ffff88042e27c180 ffff88042e282bd8 ffffffff8108ed95 ffff880400000004 0000000000000000 0000000000000c76 Call Trace: [<ffffffff8130191b>] dump_stack+0x4f/0x74 [<ffffffff8108ed95>] ___might_sleep+0x185/0x240 [<ffffffff8108eea2>] __might_sleep+0x52/0x90 [<ffffffff811817e8>] __alloc_pages_nodemask+0x268/0x410 [<ffffffff8109a43c>] ? sched_clock_local+0x1c/0x90 [<ffffffff8109a6d1>] ? local_clock+0x21/0x40 [<ffffffff810b9eb0>] ? __lock_release+0x420/0x510 [<ffffffff810b534c>] ? __lock_acquired+0x16c/0x3c0 [<ffffffff811ca265>] alloc_pages_current+0xc5/0x210 [<ffffffffa0577105>] ? rbio_is_full+0x55/0x70 [btrfs] [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 [<ffffffff81666d50>] ? _raw_spin_unlock_irqrestore+0x40/0x60 [<ffffffffa0578c0a>] full_stripe_write+0x5a/0xc0 [btrfs] [<ffffffffa0578ca9>] __raid56_parity_write+0x39/0x60 [btrfs] [<ffffffffa0578deb>] run_plug+0x11b/0x140 [btrfs] [<ffffffffa0578e33>] btrfs_raid_unplug+0x23/0x70 [btrfs] [<ffffffff812d36c2>] blk_flush_plug_list+0x82/0x1f0 [<ffffffff812e0349>] blk_sq_make_request+0x1f9/0x740 [<ffffffff812ceba2>] ? generic_make_request_checks+0x222/0x7c0 [<ffffffff812cf264>] ? blk_queue_enter+0x124/0x310 [<ffffffff812cf1d2>] ? blk_queue_enter+0x92/0x310 [<ffffffff812d0ae2>] generic_make_request+0x172/0x2c0 [<ffffffff812d0ad4>] ? generic_make_request+0x164/0x2c0 [<ffffffff812d0ca0>] submit_bio+0x70/0x140 [<ffffffffa0577b29>] ? rbio_add_io_page+0x99/0x150 [btrfs] [<ffffffffa0578a89>] finish_rmw+0x4d9/0x600 [btrfs] [<ffffffffa0578c4c>] full_stripe_write+0x9c/0xc0 [btrfs] [<ffffffffa057ab7f>] raid56_parity_write+0xef/0x160 [btrfs] [<ffffffffa052bd83>] btrfs_map_bio+0xe3/0x2d0 [btrfs] [<ffffffffa04fbd6d>] btrfs_submit_bio_hook+0x8d/0x1d0 [btrfs] [<ffffffffa05173c4>] submit_one_bio+0x74/0xb0 [btrfs] [<ffffffffa0517f55>] submit_extent_page+0xe5/0x1c0 [btrfs] [<ffffffffa0519b18>] __extent_writepage_io+0x408/0x4c0 [btrfs] [<ffffffffa05179c0>] ? alloc_dummy_extent_buffer+0x140/0x140 [btrfs] [<ffffffffa051dc88>] __extent_writepage+0x218/0x3a0 [btrfs] [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 [<ffffffffa051e2c9>] extent_write_cache_pages.clone.0+0x2f9/0x400 [btrfs] [<ffffffffa051e422>] extent_writepages+0x52/0x70 [btrfs] [<ffffffffa05001f0>] ? btrfs_set_inode_index+0x70/0x70 [btrfs] [<ffffffffa04fcc17>] btrfs_writepages+0x27/0x30 [btrfs] [<ffffffff81184df3>] do_writepages+0x23/0x40 [<ffffffff81212229>] __writeback_single_inode+0x89/0x4d0 [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480 [<ffffffff8121295f>] ? writeback_sb_inodes+0x15f/0x480 [<ffffffff81212ad2>] writeback_sb_inodes+0x2d2/0x480 [<ffffffff810b1397>] ? down_read_trylock+0x57/0x60 [<ffffffff811e6805>] ? trylock_super+0x25/0x60 [<ffffffff810d629f>] ? rcu_read_lock_sched_held+0x4f/0x90 [<ffffffff81212d0c>] __writeback_inodes_wb+0x8c/0xc0 [<ffffffff812130b5>] wb_writeback+0x2b5/0x500 [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0 [<ffffffff810660a8>] ? __local_bh_enable_ip+0x68/0xc0 [<ffffffff81213362>] ? wb_do_writeback+0x62/0x310 [<ffffffff812133c1>] wb_do_writeback+0xc1/0x310 [<ffffffff8107c3d9>] ? set_worker_desc+0x79/0x90 [<ffffffff81213842>] wb_workfn+0x92/0x330 [<ffffffff8107f133>] process_one_work+0x223/0x730 [<ffffffff8107f083>] ? process_one_work+0x173/0x730 [<ffffffff8108035f>] ? worker_thread+0x18f/0x430 [<ffffffff810802ed>] worker_thread+0x11d/0x430 [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0 [<ffffffff810858df>] kthread+0xef/0x110 [<ffffffff8108f74e>] ? schedule_tail+0x1e/0xd0 [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 [<ffffffff816673bf>] ret_from_fork+0x3f/0x70 [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70 Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- fs/btrfs/raid56.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)