From 3afae09ffea5e08f523823be99a784675995d6bb Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Mon, 11 Jan 2021 17:42:53 +0800 Subject: f2fs: compress: fix potential deadlock generic/269 reports a hangtask issue, the root cause is ABBA deadlock described as below: Thread A Thread B - down_write(&sbi->gc_lock) -- A - f2fs_write_data_pages - lock all pages in cluster -- B - f2fs_write_multi_pages - f2fs_write_raw_pages - f2fs_write_single_data_page - f2fs_balance_fs - down_write(&sbi->gc_lock) -- A - f2fs_gc - do_garbage_collect - ra_data_block - pagecache_get_page -- B To fix this, it needs to avoid calling f2fs_balance_fs() if there is still cluster pages been locked in context of cluster writeback, so instead, let's call f2fs_balance_fs() in the end of f2fs_write_raw_pages() when all cluster pages were unlocked. Fixes: 4c8ff7095bef ("f2fs: support data compression") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'fs/f2fs/data.c') diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 4d80f00e5e40..c7bb07dd9a20 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2671,7 +2671,8 @@ int f2fs_write_single_data_page(struct page *page, int *submitted, sector_t *last_block, struct writeback_control *wbc, enum iostat_type io_type, - int compr_blocks) + int compr_blocks, + bool allow_balance) { struct inode *inode = page->mapping->host; struct f2fs_sb_info *sbi = F2FS_I_SB(inode); @@ -2809,7 +2810,7 @@ out: } unlock_page(page); if (!S_ISDIR(inode->i_mode) && !IS_NOQUOTA(inode) && - !F2FS_I(inode)->cp_task) + !F2FS_I(inode)->cp_task && allow_balance) f2fs_balance_fs(sbi, need_balance_fs); if (unlikely(f2fs_cp_error(sbi))) { @@ -2856,7 +2857,7 @@ out: #endif return f2fs_write_single_data_page(page, NULL, NULL, NULL, - wbc, FS_DATA_IO, 0); + wbc, FS_DATA_IO, 0, true); } /* @@ -3024,7 +3025,8 @@ continue_unlock: } #endif ret = f2fs_write_single_data_page(page, &submitted, - &bio, &last_block, wbc, io_type, 0); + &bio, &last_block, wbc, io_type, + 0, true); if (ret == AOP_WRITEPAGE_ACTIVATE) unlock_page(page); #ifdef CONFIG_F2FS_FS_COMPRESSION -- cgit v1.2.3