From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:39661 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750960AbbLJKQl (ORCPT ); Thu, 10 Dec 2015 05:16:41 -0500 Date: Thu, 10 Dec 2015 11:08:20 +0100 From: Jan Kara To: Brian Foster Cc: Josef Bacik , linux-fsdevel@vger.kernel.org, kernel-team@fb.com, viro@ZenIV.linux.org.uk, hch@infradead.org, david@fromorbit.com, jack@suse.cz, Dave Chinner Subject: Re: [PATCH 6/8] bdi: add a new writeback list for sync Message-ID: <20151210100820.GB30985@quack.suse.cz> References: <1435116242-27495-1-git-send-email-jbacik@fb.com> <1435116242-27495-7-git-send-email-jbacik@fb.com> <20151209184030.GD45171@bfoster.bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151209184030.GD45171@bfoster.bfoster> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed 09-12-15 13:40:30, Brian Foster wrote: > On Tue, Jun 23, 2015 at 08:24:00PM -0700, Josef Bacik wrote: > > From: Dave Chinner > > > > wait_sb_inodes() current does a walk of all inodes in the filesystem > > to find dirty one to wait on during sync. This is highly > > inefficient and wastes a lot of CPU when there are lots of clean > > cached inodes that we don't need to wait on. > > > > To avoid this "all inode" walk, we need to track inodes that are > > currently under writeback that we need to wait for. We do this by > > adding inodes to a writeback list on the bdi when the mapping is > > first tagged as having pages under writeback. wait_sb_inodes() can > > then walk this list of "inodes under IO" and wait specifically just > > for the inodes that the current sync(2) needs to wait for. > > > > To avoid needing all the realted locking to be safe against > > interrupts, Jan Kara suggested that we be lazy about removal from > > the writeback list. That is, we don't remove inodes from the > > writeback list on IO completion, but do it directly during a > > wait_sb_inodes() walk. > > > > This means that the a rare sync(2) call will have some work to do > > skipping clean inodes However, in the current problem case of > > concurrent sync workloads, concurrent wait_sb_inodes() calls only > > walk the very recently dispatched inodes and hence should have very > > little work to do. > > > > This also means that we have to remove the inodes from the writeback > > list during eviction. Do this in inode_wait_for_writeback() once > > all writeback on the inode is complete. > > > > Signed-off-by: Dave Chinner > > Signed-off-by: Josef Bacik > > Tested-by: Dave Chinner > > Reviewed-by: Jan Kara > > --- Hi, > My understanding is this (and the subsequent) patch were never merged > due to conflicts with the cgroup aware writeback stuff that had been > merged. Yes. Thanks for bringing this up. At that point I thought Josef will take care of rebasing the patches and it fell out of my radar. > I think the fundamental approach of this patch still solves the > original problem, the writeback inodes are just always tracked on the > root bdi_writeback rather than the per-cgroup bdi_writeback the inode > was associated with before writeback. I was thinking about this and realized that the original patch actually has a flaw. In case there are several partitions on a bdi and sync_fs() would be called for two filesystems on the same bdi, then one of those sync_fs() calls would splice the whole b_writeback list into its private list in wait_sb_inodes() and the other sync_fs() call would return too early because it would find b_writeback list empty. Given that we need the list of inodes under writeback only for sync(2) / sync_fs(2) purposes it would work the best to track those inodes in the per-superblock list. We would miss block device inode this way but that one is waited-on in a special way anyway (in __sync_blockdev() / fdatawait_one_bdev()). Also that way any strange interaction and confusion with cgroup writeback is avoided. > Any thoughts on that are appreciated. Otherwise, I'm trying to rebase > this and I've hit a lockdep splat [1] that suggests the locking for the > writeback list needs to be tweaked one way or another. Note that lockdep > fires with this original version as well, so I don't think this is a new > issue. Yeah, it looks that the issue has been there forever. When we have per-sb list then we need a different lock to protect the list anyway. So having a dedicated lock for the list which would be irqsave would be the easiest solution. But note that in that case the locking of i_lock in wait_inodes_sb() has to be dealt with as well since making i_lock irqsafe is not an option. I think we could avoid having the dedicated lock irqsafe if we moved bdi_mark_inode_writeback() call from under mapping->tree_lock (to happen later in __test_set_page_writeback()). However that needs some careful thinking about how the interactions of __test_set_page_writeback() with the list handling in wait_inodes_sb() work out. Honza > [1] lockdep splat: > > [ INFO: possible irq lock inversion dependency detected ] > 4.4.0-rc4+ #54 Not tainted > --------------------------------------------------------- > swapper/0/0 just changed the state of lock: > (&(&mapping->tree_lock)->rlock){-.....}, at: [] test_clear_page_writeback+0x5d/0x210 > but this lock took another, HARDIRQ-unsafe lock in the past: > (&(&wb->list_lock)->rlock){+.+...}#012#012and interrupts could create inverse lock ordering between them. > #012other info that might help us debug this: > Possible interrupt unsafe locking scenario: > CPU0 CPU1 > ---- ---- > lock(&(&wb->list_lock)->rlock); > local_irq_disable(); > lock(&(&mapping->tree_lock)->rlock); > lock(&(&wb->list_lock)->rlock); > > lock(&(&mapping->tree_lock)->rlock); > #012 *** DEADLOCK *** > no locks held by swapper/0/0. > #012the shortest dependencies between 2nd lock and 1st lock: > -> (&(&wb->list_lock)->rlock){+.+...} ops: 194 { > HARDIRQ-ON-W at: > [] __lock_acquire+0x819/0x1a50 > [] lock_acquire+0xce/0x1c0 > [] _raw_spin_lock+0x38/0x50 > [] __mark_inode_dirty+0x3d9/0x5e0 > [] generic_update_time+0x79/0xd0 > [] touch_atime+0xa8/0xd0 > [] iterate_dir+0xe3/0x130 > [] SyS_getdents+0x9d/0x130 > [] entry_SYSCALL_64_fastpath+0x12/0x76 > SOFTIRQ-ON-W at: > [] __lock_acquire+0x84a/0x1a50 > [] lock_acquire+0xce/0x1c0 > [] _raw_spin_lock+0x38/0x50 > [] __mark_inode_dirty+0x3d9/0x5e0 > [] generic_update_time+0x79/0xd0 > [] touch_atime+0xa8/0xd0 > [] iterate_dir+0xe3/0x130 > [] SyS_getdents+0x9d/0x130 > [] entry_SYSCALL_64_fastpath+0x12/0x76 > INITIAL USE at: > [] __lock_acquire+0x3f8/0x1a50 > [] lock_acquire+0xce/0x1c0 > [] _raw_spin_lock+0x38/0x50 > [] __mark_inode_dirty+0x3d9/0x5e0 > [] generic_update_time+0x79/0xd0 > [] touch_atime+0xa8/0xd0 > [] iterate_dir+0xe3/0x130 > [] SyS_getdents+0x9d/0x130 > [] entry_SYSCALL_64_fastpath+0x12/0x76 > } > ... key at: [] __key.37388+0x0/0x8 > ... acquired at: > [] lock_acquire+0xce/0x1c0 > [] _raw_spin_lock+0x38/0x50 > [] bdi_mark_inode_writeback+0x67/0xd0 > [] __test_set_page_writeback+0x112/0x200 > [] __block_write_full_page.constprop.44+0xec/0x400 > [] block_write_full_page+0xfe/0x190 > [] blkdev_writepage+0x18/0x20 > [] __writepage+0x16/0x40 > [] write_cache_pages+0x225/0x5f0 > [] generic_writepages+0x54/0x80 > [] do_writepages+0x21/0x30 > [] __filemap_fdatawrite_range+0x80/0xb0 > [] filemap_write_and_wait_range+0x2d/0x70 > [] blkdev_fsync+0x1b/0x50 > [] vfs_fsync_range+0x4b/0xb0 > [] do_fsync+0x3d/0x70 > [] SyS_fsync+0x10/0x20 > [] entry_SYSCALL_64_fastpath+0x12/0x76 > > -> (&(&mapping->tree_lock)->rlock){-.....} ops: 16821 { > IN-HARDIRQ-W at: > [] __lock_acquire+0x999/0x1a50 > [] lock_acquire+0xce/0x1c0 > [] _raw_spin_lock_irqsave+0x50/0x70 > [] test_clear_page_writeback+0x5d/0x210 > [] end_page_writeback+0x1f/0xa0 > [] end_buffer_async_write+0xd3/0x1a0 > [] end_bio_bh_io_sync+0x28/0x40 > [] bio_endio+0x3f/0x60 > [] dec_pending+0x149/0x310 > [] clone_endio+0x76/0xe0 > [] bio_endio+0x3f/0x60 > [] blk_update_request+0xb2/0x3a0 > [] blk_mq_end_request+0x1a/0x70 > [] virtblk_request_done+0x3f/0x70 [virtio_blk] > [] __blk_mq_complete_request_remote+0x13/0x20 > [] flush_smp_call_function_queue+0x5f/0x160 > [] generic_smp_call_function_single_interrupt+0x13/0x60 > [] smp_call_function_single_interrupt+0x27/0x40 > [] call_function_single_interrupt+0x8c/0xa0 > [] default_idle+0x23/0x150 > [] arch_cpu_idle+0xf/0x20 > [] default_idle_call+0x2a/0x40 > [] cpu_startup_entry+0x384/0x3f0 > [] rest_init+0x13a/0x140 > [] start_kernel+0x49e/0x4bf > [] x86_64_start_reservations+0x2a/0x2c > [] x86_64_start_kernel+0x145/0x168 > INITIAL USE at: > [] __lock_acquire+0x3f8/0x1a50 > [] lock_acquire+0xce/0x1c0 > [] _raw_spin_lock_irq+0x44/0x60 > [] __add_to_page_cache_locked+0xbc/0x340 > [] add_to_page_cache_lru+0x37/0x90 > [] pagecache_get_page+0xb7/0x200 > [] grab_cache_page_write_begin+0x29/0x40 > [] simple_write_begin+0x28/0x1c0 > [] generic_perform_write+0xd1/0x1e0 > [] __generic_file_write_iter+0x1a2/0x1e0 > [] generic_file_write_iter+0xe8/0x1e0 > [] __vfs_write+0xc9/0x110 > [] vfs_write+0xa9/0x1a0 > [] SyS_write+0x58/0xd0 > [] xwrite+0x29/0x5c > [] do_copy+0x2a/0xb8 > [] write_buffer+0x23/0x34 > [] unpack_to_rootfs+0xfd/0x294 > [] populate_rootfs+0x5c/0x108 > [] do_one_initcall+0xb3/0x200 > [] kernel_init_freeable+0x1ee/0x28d > [] kernel_init+0xe/0xe0 > [] ret_from_fork+0x3f/0x70 > } > ... key at: [] __key.39560+0x0/0x8 > ... acquired at: > [] check_usage_forwards+0x15b/0x160 > [] mark_lock+0x333/0x610 > [] __lock_acquire+0x999/0x1a50 > [] lock_acquire+0xce/0x1c0 > [] _raw_spin_lock_irqsave+0x50/0x70 > [] test_clear_page_writeback+0x5d/0x210 > [] end_page_writeback+0x1f/0xa0 > [] end_buffer_async_write+0xd3/0x1a0 > [] end_bio_bh_io_sync+0x28/0x40 > [] bio_endio+0x3f/0x60 > [] dec_pending+0x149/0x310 > [] clone_endio+0x76/0xe0 > [] bio_endio+0x3f/0x60 > [] blk_update_request+0xb2/0x3a0 > [] blk_mq_end_request+0x1a/0x70 > [] virtblk_request_done+0x3f/0x70 [virtio_blk] > [] __blk_mq_complete_request_remote+0x13/0x20 > [] flush_smp_call_function_queue+0x5f/0x160 > [] generic_smp_call_function_single_interrupt+0x13/0x60 > [] smp_call_function_single_interrupt+0x27/0x40 > [] call_function_single_interrupt+0x8c/0xa0 > [] default_idle+0x23/0x150 > [] arch_cpu_idle+0xf/0x20 > [] default_idle_call+0x2a/0x40 > [] cpu_startup_entry+0x384/0x3f0 > [] rest_init+0x13a/0x140 > [] start_kernel+0x49e/0x4bf > [] x86_64_start_reservations+0x2a/0x2c > [] x86_64_start_kernel+0x145/0x168 > > #012stack backtrace: > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc4+ #54 > Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > 0000000000000000 06776aa479e380f6 ffff88011fc03ad0 ffffffff813dd019 > ffffffff82a0f120 ffff88011fc03b10 ffffffff811c184d ffffffff81c10be8 > ffffffff81c10be8 ffffffff81c10500 ffffffff81a56510 0000000000000000 > Call Trace: > [] dump_stack+0x4b/0x72 > [] print_irq_inversion_bug.part.38+0x1a4/0x1b0 > [] check_usage_forwards+0x15b/0x160 > [] mark_lock+0x333/0x610 > [] ? check_usage_backwards+0x160/0x160 > [] __lock_acquire+0x999/0x1a50 > [] lock_acquire+0xce/0x1c0 > [] ? test_clear_page_writeback+0x5d/0x210 > [] _raw_spin_lock_irqsave+0x50/0x70 > [] ? test_clear_page_writeback+0x5d/0x210 > [] test_clear_page_writeback+0x5d/0x210 > [] end_page_writeback+0x1f/0xa0 > [] end_buffer_async_write+0xd3/0x1a0 > [] end_bio_bh_io_sync+0x28/0x40 > [] bio_endio+0x3f/0x60 > [] dec_pending+0x149/0x310 > [] ? mempool_free+0x29/0x80 > [] clone_endio+0x76/0xe0 > [] bio_endio+0x3f/0x60 > [] blk_update_request+0xb2/0x3a0 > [] ? blkdev_issue_zeroout+0xf0/0xf0 > [] blk_mq_end_request+0x1a/0x70 > [] virtblk_request_done+0x3f/0x70 [virtio_blk] > [] __blk_mq_complete_request_remote+0x13/0x20 > [] flush_smp_call_function_queue+0x5f/0x160 > [] generic_smp_call_function_single_interrupt+0x13/0x60 > [] smp_call_function_single_interrupt+0x27/0x40 > [] call_function_single_interrupt+0x8c/0xa0 > [] ? native_safe_halt+0x6/0x10 > [] default_idle+0x23/0x150 > [] arch_cpu_idle+0xf/0x20 > [] default_idle_call+0x2a/0x40 > [] cpu_startup_entry+0x384/0x3f0 > [] rest_init+0x13a/0x140 > [] start_kernel+0x49e/0x4bf > [] ? early_idt_handler_array+0x120/0x120 > [] x86_64_start_reservations+0x2a/0x2c > [] x86_64_start_kernel+0x145/0x168 > > > fs/block_dev.c | 2 + > > fs/fs-writeback.c | 148 +++++++++++++++++++++++++++++++++++--------- > > fs/inode.c | 1 + > > include/linux/backing-dev.h | 5 ++ > > include/linux/fs.h | 1 + > > mm/backing-dev.c | 1 + > > mm/page-writeback.c | 14 +++++ > > 7 files changed, 144 insertions(+), 28 deletions(-) > > > > diff --git a/fs/block_dev.c b/fs/block_dev.c > > index f2a89be..2726ff1 100644 > > --- a/fs/block_dev.c > > +++ b/fs/block_dev.c > > @@ -64,6 +64,8 @@ void kill_bdev(struct block_device *bdev) > > { > > struct address_space *mapping = bdev->bd_inode->i_mapping; > > > > + bdi_clear_inode_writeback(inode_to_bdi(bdev->bd_inode), > > + bdev->bd_inode); > > if (mapping->nrpages == 0 && mapping->nrshadows == 0) > > return; > > > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > > index aa72536..5c005ad 100644 > > --- a/fs/fs-writeback.c > > +++ b/fs/fs-writeback.c > > @@ -210,6 +210,34 @@ void inode_wb_list_del(struct inode *inode) > > } > > > > /* > > + * mark an inode as under writeback on the given bdi > > + */ > > +void bdi_mark_inode_writeback(struct backing_dev_info *bdi, struct inode *inode) > > +{ > > + WARN_ON_ONCE(bdi != inode_to_bdi(inode)); > > + if (list_empty(&inode->i_wb_list)) { > > + spin_lock(&bdi->wb.list_lock); > > + if (list_empty(&inode->i_wb_list)) > > + list_add_tail(&inode->i_wb_list, &bdi->wb.b_writeback); > > + spin_unlock(&bdi->wb.list_lock); > > + } > > +} > > + > > +/* > > + * clear an inode as under writeback on the given bdi > > + */ > > +void bdi_clear_inode_writeback(struct backing_dev_info *bdi, > > + struct inode *inode) > > +{ > > + WARN_ON_ONCE(bdi != inode_to_bdi(inode)); > > + if (!list_empty(&inode->i_wb_list)) { > > + spin_lock(&bdi->wb.list_lock); > > + list_del_init(&inode->i_wb_list); > > + spin_unlock(&bdi->wb.list_lock); > > + } > > +} > > + > > +/* > > * Redirty an inode: set its when-it-was dirtied timestamp and move it to the > > * furthest end of its superblock's dirty-inode list. > > * > > @@ -383,13 +411,28 @@ static void __inode_wait_for_writeback(struct inode *inode) > > } > > > > /* > > - * Wait for writeback on an inode to complete. Caller must have inode pinned. > > + * Wait for writeback on an inode to complete during eviction. Caller must have > > + * inode pinned. > > */ > > void inode_wait_for_writeback(struct inode *inode) > > { > > + BUG_ON(!(inode->i_state & I_FREEING)); > > + > > spin_lock(&inode->i_lock); > > __inode_wait_for_writeback(inode); > > spin_unlock(&inode->i_lock); > > + > > + /* > > + * For a bd_inode when we do inode_to_bdi we'll want to get the bdev for > > + * the inode and then deref bdev->bd_disk, which at this point has been > > + * set to NULL, so we would panic. At the point we are dropping our > > + * bd_inode we won't have any pages under writeback on the device so > > + * this is safe. But just in case we'll assert to make sure we don't > > + * screw this up. > > + */ > > + if (!sb_is_blkdev_sb(inode->i_sb)) > > + bdi_clear_inode_writeback(inode_to_bdi(inode), inode); > > + BUG_ON(!list_empty(&inode->i_wb_list)); > > } > > > > /* > > @@ -1372,7 +1415,9 @@ EXPORT_SYMBOL(__mark_inode_dirty); > > */ > > static void wait_sb_inodes(struct super_block *sb) > > { > > - struct inode *inode, *old_inode = NULL; > > + struct backing_dev_info *bdi = sb->s_bdi; > > + LIST_HEAD(sync_list); > > + struct inode *iput_inode = NULL; > > > > /* > > * We need to be protected against the filesystem going from > > @@ -1380,48 +1425,95 @@ static void wait_sb_inodes(struct super_block *sb) > > */ > > WARN_ON(!rwsem_is_locked(&sb->s_umount)); > > > > - mutex_lock(&sb->s_sync_lock); > > - spin_lock(&sb->s_inode_list_lock); > > - > > /* > > - * Data integrity sync. Must wait for all pages under writeback, > > - * because there may have been pages dirtied before our sync > > - * call, but which had writeout started before we write it out. > > - * In which case, the inode may not be on the dirty list, but > > - * we still have to wait for that writeout. > > + * Data integrity sync. Must wait for all pages under writeback, because > > + * there may have been pages dirtied before our sync call, but which had > > + * writeout started before we write it out. In which case, the inode > > + * may not be on the dirty list, but we still have to wait for that > > + * writeout. > > + * > > + * To avoid syncing inodes put under IO after we have started here, > > + * splice the io list to a temporary list head and walk that. Newly > > + * dirtied inodes will go onto the primary list so we won't wait for > > + * them. This is safe to do as we are serialised by the s_sync_lock, > > + * so we'll complete processing the complete list before the next > > + * sync operation repeats the splice-and-walk process. > > + * > > + * Inodes that have pages under writeback after we've finished the wait > > + * may or may not be on the primary list. They had pages under put IO > > + * after we started our wait, so we need to make sure the next sync or > > + * IO completion treats them correctly, Move them back to the primary > > + * list and restart the walk. > > + * > > + * Inodes that are clean after we have waited for them don't belong on > > + * any list, so simply remove them from the sync list and move onwards. > > */ > > - list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { > > + mutex_lock(&sb->s_sync_lock); > > + spin_lock(&bdi->wb.list_lock); > > + list_splice_init(&bdi->wb.b_writeback, &sync_list); > > + > > + while (!list_empty(&sync_list)) { > > + struct inode *inode = list_first_entry(&sync_list, struct inode, > > + i_wb_list); > > struct address_space *mapping = inode->i_mapping; > > > > + /* > > + * We are lazy on IO completion and don't remove inodes from the > > + * list when they are clean. Detect that immediately and skip > > + * inodes we don't ahve to wait on. > > + */ > > + if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) { > > + list_del_init(&inode->i_wb_list); > > + cond_resched_lock(&bdi->wb.list_lock); > > + continue; > > + } > > + > > spin_lock(&inode->i_lock); > > - if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || > > - (mapping->nrpages == 0)) { > > + if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { > > + list_move(&inode->i_wb_list, &bdi->wb.b_writeback); > > spin_unlock(&inode->i_lock); > > + cond_resched_lock(&bdi->wb.list_lock); > > continue; > > } > > __iget(inode); > > spin_unlock(&inode->i_lock); > > - spin_unlock(&sb->s_inode_list_lock); > > + spin_unlock(&bdi->wb.list_lock); > > > > - /* > > - * We hold a reference to 'inode' so it couldn't have been > > - * removed from s_inodes list while we dropped the > > - * s_inode_list_lock. We cannot iput the inode now as we can > > - * be holding the last reference and we cannot iput it under > > - * s_inode_list_lock. So we keep the reference and iput it > > - * later. > > - */ > > - iput(old_inode); > > - old_inode = inode; > > + if (iput_inode) > > + iput(iput_inode); > > > > filemap_fdatawait(mapping); > > - > > cond_resched(); > > > > - spin_lock(&sb->s_inode_list_lock); > > + /* > > + * the inode has been written back now, so check whether we > > + * still have pages under IO and move it back to the primary > > + * list if necessary. We really need the mapping->tree_lock > > + * here because bdi_mark_inode_writeback may have not done > > + * anything because we were on the spliced list and we need to > > + * check TAG_WRITEBACK. > > + */ > > + spin_lock_irq(&mapping->tree_lock); > > + spin_lock(&bdi->wb.list_lock); > > + if (mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) { > > + WARN_ON(list_empty(&inode->i_wb_list)); > > + list_move(&inode->i_wb_list, &bdi->wb.b_writeback); > > + } else > > + list_del_init(&inode->i_wb_list); > > + spin_unlock_irq(&mapping->tree_lock); > > + > > + /* > > + * can't iput inode while holding the wb.list_lock. Save it for > > + * the next time through the loop when we drop all our spin > > + * locks. > > + */ > > + iput_inode = inode; > > } > > - spin_unlock(&sb->s_inode_list_lock); > > - iput(old_inode); > > + spin_unlock(&bdi->wb.list_lock); > > + > > + if (iput_inode) > > + iput(iput_inode); > > + > > mutex_unlock(&sb->s_sync_lock); > > } > > > > diff --git a/fs/inode.c b/fs/inode.c > > index 770d684..8f00557 100644 > > --- a/fs/inode.c > > +++ b/fs/inode.c > > @@ -357,6 +357,7 @@ void inode_init_once(struct inode *inode) > > INIT_HLIST_NODE(&inode->i_hash); > > INIT_LIST_HEAD(&inode->i_devices); > > INIT_LIST_HEAD(&inode->i_io_list); > > + INIT_LIST_HEAD(&inode->i_wb_list); > > INIT_LIST_HEAD(&inode->i_lru); > > address_space_init_once(&inode->i_data); > > i_size_ordered_init(inode); > > diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h > > index d87d8ec..0d5bca2 100644 > > --- a/include/linux/backing-dev.h > > +++ b/include/linux/backing-dev.h > > @@ -56,6 +56,7 @@ struct bdi_writeback { > > struct list_head b_io; /* parked for writeback */ > > struct list_head b_more_io; /* parked for more writeback */ > > struct list_head b_dirty_time; /* time stamps are dirty */ > > + struct list_head b_writeback; /* inodes under writeback */ > > spinlock_t list_lock; /* protects the b_* lists */ > > }; > > > > @@ -123,6 +124,10 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi); > > void bdi_writeback_workfn(struct work_struct *work); > > int bdi_has_dirty_io(struct backing_dev_info *bdi); > > void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi); > > +void bdi_mark_inode_writeback(struct backing_dev_info *bdi, > > + struct inode *inode); > > +void bdi_clear_inode_writeback(struct backing_dev_info *bdi, > > + struct inode *inode); > > > > extern spinlock_t bdi_lock; > > extern struct list_head bdi_list; > > diff --git a/include/linux/fs.h b/include/linux/fs.h > > index 6dd2ab2..d3baa08 100644 > > --- a/include/linux/fs.h > > +++ b/include/linux/fs.h > > @@ -636,6 +636,7 @@ struct inode { > > struct list_head i_io_list; /* backing dev IO list */ > > struct list_head i_lru; /* inode LRU list */ > > struct list_head i_sb_list; > > + struct list_head i_wb_list; /* backing dev writeback list */ > > union { > > struct hlist_head i_dentry; > > struct rcu_head i_rcu; > > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > > index e9ed047..ea39301 100644 > > --- a/mm/backing-dev.c > > +++ b/mm/backing-dev.c > > @@ -369,6 +369,7 @@ static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi) > > INIT_LIST_HEAD(&wb->b_io); > > INIT_LIST_HEAD(&wb->b_more_io); > > INIT_LIST_HEAD(&wb->b_dirty_time); > > + INIT_LIST_HEAD(&wb->b_writeback); > > spin_lock_init(&wb->list_lock); > > INIT_DELAYED_WORK(&wb->dwork, bdi_writeback_workfn); > > } > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > > index eb59f7e..f3751d1 100644 > > --- a/mm/page-writeback.c > > +++ b/mm/page-writeback.c > > @@ -2382,11 +2382,25 @@ int __test_set_page_writeback(struct page *page, bool keep_write) > > spin_lock_irqsave(&mapping->tree_lock, flags); > > ret = TestSetPageWriteback(page); > > if (!ret) { > > + bool on_wblist; > > + > > + on_wblist = mapping_tagged(mapping, > > + PAGECACHE_TAG_WRITEBACK); > > + > > radix_tree_tag_set(&mapping->page_tree, > > page_index(page), > > PAGECACHE_TAG_WRITEBACK); > > if (bdi_cap_account_writeback(bdi)) > > __inc_bdi_stat(bdi, BDI_WRITEBACK); > > + > > + /* > > + * we can come through here when swapping anonymous > > + * pages, so we don't necessarily have an inode to > > + * track for sync. Inodes are remove lazily, so there is > > + * no equivalent in test_clear_page_writeback(). > > + */ > > + if (!on_wblist && mapping->host) > > + bdi_mark_inode_writeback(bdi, mapping->host); > > } > > if (!PageDirty(page)) > > radix_tree_tag_clear(&mapping->page_tree, > > -- > > 2.1.0 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Jan Kara SUSE Labs, CR