| From 27c7c784eb0483af495640c0cb476d0ccb5fb3ad Mon Sep 17 00:00:00 2001 |
| From: Sahitya Tummala <stummala@codeaurora.org> |
| Date: Tue, 18 Feb 2020 09:19:07 +0530 |
| Subject: [PATCH] f2fs: fix the panic in do_checkpoint() |
| |
| commit bf22c3cc8ce71454dddd772284773306a68031d8 upstream. |
| |
| There could be a scenario where f2fs_sync_meta_pages() will not |
| ensure that all F2FS_DIRTY_META pages are submitted for IO. Thus, |
| resulting in the below panic in do_checkpoint() - |
| |
| f2fs_bug_on(sbi, get_pages(sbi, F2FS_DIRTY_META) && |
| !f2fs_cp_error(sbi)); |
| |
| This can happen in a low-memory condition, where shrinker could |
| also be doing the writepage operation (stack shown below) |
| at the same time when checkpoint is running on another core. |
| |
| schedule |
| down_write |
| f2fs_submit_page_write -> by this time, this page in page cache is tagged |
| as PAGECACHE_TAG_WRITEBACK and PAGECACHE_TAG_DIRTY |
| is cleared, due to which f2fs_sync_meta_pages() |
| cannot sync this page in do_checkpoint() path. |
| f2fs_do_write_meta_page |
| __f2fs_write_meta_page |
| f2fs_write_meta_page |
| shrink_page_list |
| shrink_inactive_list |
| shrink_node_memcg |
| shrink_node |
| kswapd |
| |
| Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> |
| Reviewed-by: Chao Yu <yuchao0@huawei.com> |
| Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c |
| index 7d9fce215f46..c7891a9853e1 100644 |
| --- a/fs/f2fs/checkpoint.c |
| +++ b/fs/f2fs/checkpoint.c |
| @@ -1257,20 +1257,20 @@ static void unblock_operations(struct f2fs_sb_info *sbi) |
| f2fs_unlock_all(sbi); |
| } |
| |
| -void f2fs_wait_on_all_pages_writeback(struct f2fs_sb_info *sbi) |
| +void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type) |
| { |
| DEFINE_WAIT(wait); |
| |
| for (;;) { |
| prepare_to_wait(&sbi->cp_wait, &wait, TASK_UNINTERRUPTIBLE); |
| |
| - if (!get_pages(sbi, F2FS_WB_CP_DATA)) |
| + if (!get_pages(sbi, type)) |
| break; |
| |
| if (unlikely(f2fs_cp_error(sbi))) |
| break; |
| |
| - io_schedule_timeout(5*HZ); |
| + io_schedule_timeout(HZ/50); |
| } |
| finish_wait(&sbi->cp_wait, &wait); |
| } |
| @@ -1392,8 +1392,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) |
| |
| /* Flush all the NAT/SIT pages */ |
| f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO); |
| - f2fs_bug_on(sbi, get_pages(sbi, F2FS_DIRTY_META) && |
| - !f2fs_cp_error(sbi)); |
| |
| /* |
| * modify checkpoint |
| @@ -1501,11 +1499,11 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) |
| |
| /* Here, we have one bio having CP pack except cp pack 2 page */ |
| f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO); |
| - f2fs_bug_on(sbi, get_pages(sbi, F2FS_DIRTY_META) && |
| - !f2fs_cp_error(sbi)); |
| + /* Wait for all dirty meta pages to be submitted for IO */ |
| + f2fs_wait_on_all_pages(sbi, F2FS_DIRTY_META); |
| |
| /* wait for previous submitted meta pages writeback */ |
| - f2fs_wait_on_all_pages_writeback(sbi); |
| + f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA); |
| |
| /* flush all device cache */ |
| err = f2fs_flush_device_cache(sbi); |
| @@ -1514,7 +1512,7 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) |
| |
| /* barrier and flush checkpoint cp pack 2 page if it can */ |
| commit_checkpoint(sbi, ckpt, start_blk); |
| - f2fs_wait_on_all_pages_writeback(sbi); |
| + f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA); |
| |
| /* |
| * invalidate intermediate page cache borrowed from meta inode |
| diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h |
| index 2341e29c1197..6744f29997a9 100644 |
| --- a/fs/f2fs/f2fs.h |
| +++ b/fs/f2fs/f2fs.h |
| @@ -3165,7 +3165,7 @@ int f2fs_get_valid_checkpoint(struct f2fs_sb_info *sbi); |
| void f2fs_update_dirty_page(struct inode *inode, struct page *page); |
| void f2fs_remove_dirty_inode(struct inode *inode); |
| int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi, enum inode_type type); |
| -void f2fs_wait_on_all_pages_writeback(struct f2fs_sb_info *sbi); |
| +void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type); |
| int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc); |
| void f2fs_init_ino_entry_info(struct f2fs_sb_info *sbi); |
| int __init f2fs_create_checkpoint_caches(void); |
| diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c |
| index 715b8b2161dd..7311df665eac 100644 |
| --- a/fs/f2fs/super.c |
| +++ b/fs/f2fs/super.c |
| @@ -1086,7 +1086,7 @@ static void f2fs_put_super(struct super_block *sb) |
| /* our cp_error case, we can wait for any writeback page */ |
| f2fs_flush_merged_writes(sbi); |
| |
| - f2fs_wait_on_all_pages_writeback(sbi); |
| + f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA); |
| |
| f2fs_bug_on(sbi, sbi->fsync_node_num); |
| |
| -- |
| 2.7.4 |
| |