From f017f15f7c1893cb518ddae796f3a75c0c413a92 Mon Sep 17 00:00:00 2001 From: Wang Shilong Date: Thu, 13 Mar 2014 13:19:47 +0800 Subject: [PATCH] Btrfs: fix joining same transaction handle more than twice We hit something like the following function call flows: |->run_delalloc_range() |->btrfs_join_transaction() |->cow_file_range() |->btrfs_join_transaction() |->find_free_extent() |->btrfs_join_transaction() Trace infomation can be seen as: [ 7411.127040] ------------[ cut here ]------------ [ 7411.127060] WARNING: CPU: 0 PID: 11557 at fs/btrfs/transaction.c:383 start_transaction+0x561/0x580 [btrfs]() [ 7411.127079] CPU: 0 PID: 11557 Comm: kworker/u8:9 Tainted: G O 3.13.0+ #4 [ 7411.127080] Hardware name: LENOVO QiTianM4350/ , BIOS F1KT52AUS 05/24/2013 [ 7411.127085] Workqueue: writeback bdi_writeback_workfn (flush-btrfs-5) [ 7411.127092] Call Trace: [ 7411.127097] [] dump_stack+0x45/0x56 [ 7411.127101] [] warn_slowpath_common+0x7d/0xa0 [ 7411.127102] [] warn_slowpath_null+0x1a/0x20 [ 7411.127109] [] start_transaction+0x561/0x580 [btrfs] [ 7411.127115] [] btrfs_join_transaction+0x17/0x20 [btrfs] [ 7411.127120] [] find_free_extent+0xa21/0xb50 [btrfs] [ 7411.127126] [] btrfs_reserve_extent+0xa8/0x1a0 [btrfs] [ 7411.127131] [] btrfs_alloc_free_block+0xee/0x440 [btrfs] [ 7411.127137] [] ? btree_set_page_dirty+0xe/0x10 [btrfs] [ 7411.127142] [] __btrfs_cow_block+0x121/0x530 [btrfs] [ 7411.127146] [] btrfs_cow_block+0x11f/0x1c0 [btrfs] [ 7411.127151] [] btrfs_search_slot+0x1d4/0x9c0 [btrfs] [ 7411.127157] [] btrfs_lookup_file_extent+0x37/0x40 [btrfs] [ 7411.127163] [] __btrfs_drop_extents+0x16c/0xd90 [btrfs] [ 7411.127169] [] ? start_transaction+0x93/0x580 [btrfs] [ 7411.127171] [] ? kmem_cache_alloc+0x132/0x140 [ 7411.127176] [] ? btrfs_alloc_path+0x1a/0x20 [btrfs] [ 7411.127182] [] cow_file_range_inline+0x181/0x2e0 [btrfs] [ 7411.127187] [] cow_file_range+0x2ed/0x440 [btrfs] [ 7411.127194] [] ? free_extent_buffer+0x4f/0xb0 [btrfs] [ 7411.127200] [] run_delalloc_nocow+0x38f/0xa60 [btrfs] [ 7411.127207] [] ? test_range_bit+0x30/0x180 [btrfs] [ 7411.127212] [] run_delalloc_range+0x2e8/0x350 [btrfs] [ 7411.127219] [] ? find_lock_delalloc_range+0x1a9/0x1e0 [btrfs] [ 7411.127222] [] ? blk_queue_bio+0x2c1/0x330 [ 7411.127228] [] __extent_writepage+0x2f4/0x760 [btrfs] Here we fix it by avoiding joining transaction again if we have held a transaction handle when allocating chunk in find_free_extent(). Signed-off-by: Wang Shilong Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 203d9a5..aff579d 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -6616,8 +6616,14 @@ loop: loop++; if (loop == LOOP_ALLOC_CHUNK) { struct btrfs_trans_handle *trans; + int exist = 0; + + trans = current->journal_info; + if (trans) + exist = 1; + else + trans = btrfs_join_transaction(root); - trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); goto out; @@ -6634,7 +6640,8 @@ loop: root, ret); else ret = 0; - btrfs_end_transaction(trans, root); + if (!exist) + btrfs_end_transaction(trans, root); if (ret) goto out; } -- 2.7.4