From 186857c5a14aee85cace2ae7a36c6e43b9d3c7a5 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Tue, 2 Apr 2019 18:52:19 +0800 Subject: [PATCH] f2fs: fix potential recursive call when enabling data_flush As Hagbard Celine reported: Hi, this is a long standing bug that I've hit before on older kernels, but I was not able to get the syslog saved because of the nature of the bug. This time I had booted form a pen-drive, and was able to save the log to it's efi-partition. What i did to trigger it was to create a partition and format it f2fs, then mount it with options: "rw,relatime,lazytime,background_gc=on,disable_ext_identify,discard,heap,user_xattr,inline_xattr,acl,inline_data,inline_dentry,flush_merge,data_flush,extent_cache,mode=adaptive,active_logs=6,whint_mode=fs-based,alloc_mode=default,fsync_mode=strict". Then I unpacked a big .tar.xz to the partition (I used a gentoo-stage3-tarball as I was in process of installing Gentoo). Same options just without data_flush gives no problems. Mar 20 20:54:01 usbgentoo kernel: FAT-fs (nvme0n1p4): Volume was not properly unmounted. Some data may be corrupt. Please run fsck. Mar 20 21:05:23 usbgentoo kernel: kworker/dying (1588) used greatest stack depth: 12064 bytes left Mar 20 21:06:40 usbgentoo kernel: BUG: stack guard page was hit at 00000000a4b0733c (stack is 0000000056016422..0000000096e7463f) Mar 20 21:06:40 usbgentoo kernel: kernel stack overflow ...... Mar 20 21:06:40 usbgentoo kernel: Call Trace: Mar 20 21:06:40 usbgentoo kernel: read_node_page+0x71/0xf0 Mar 20 21:06:40 usbgentoo kernel: ? xas_load+0x8/0x50 Mar 20 21:06:40 usbgentoo kernel: __get_node_page+0x73/0x2a0 Mar 20 21:06:40 usbgentoo kernel: f2fs_get_dnode_of_data+0x34e/0x580 Mar 20 21:06:40 usbgentoo kernel: f2fs_write_inline_data+0x5e/0x2a0 Mar 20 21:06:40 usbgentoo kernel: __write_data_page+0x421/0x690 Mar 20 21:06:40 usbgentoo kernel: f2fs_write_cache_pages+0x1cf/0x460 Mar 20 21:06:40 usbgentoo kernel: f2fs_write_data_pages+0x2b3/0x2e0 Mar 20 21:06:40 usbgentoo kernel: ? f2fs_inode_chksum_verify+0x1d/0xc0 Mar 20 21:06:40 usbgentoo kernel: ? read_node_page+0x71/0xf0 Mar 20 21:06:40 usbgentoo kernel: do_writepages+0x3c/0xd0 Mar 20 21:06:40 usbgentoo kernel: __filemap_fdatawrite_range+0x7c/0xb0 Mar 20 21:06:40 usbgentoo kernel: f2fs_sync_dirty_inodes+0xf2/0x200 Mar 20 21:06:40 usbgentoo kernel: f2fs_balance_fs_bg+0x2a3/0x2c0 Mar 20 21:06:40 usbgentoo kernel: ? f2fs_inode_dirtied+0x21/0xc0 Mar 20 21:06:40 usbgentoo kernel: f2fs_balance_fs+0xd6/0x2b0 Mar 20 21:06:40 usbgentoo kernel: __write_data_page+0x4fb/0x690 ...... Mar 20 21:06:40 usbgentoo kernel: __writeback_single_inode+0x2a1/0x340 Mar 20 21:06:40 usbgentoo kernel: ? soft_cursor+0x1b4/0x220 Mar 20 21:06:40 usbgentoo kernel: writeback_sb_inodes+0x1d5/0x3e0 Mar 20 21:06:40 usbgentoo kernel: __writeback_inodes_wb+0x58/0xa0 Mar 20 21:06:40 usbgentoo kernel: wb_writeback+0x250/0x2e0 Mar 20 21:06:40 usbgentoo kernel: ? 0xffffffff8c000000 Mar 20 21:06:40 usbgentoo kernel: ? cpumask_next+0x16/0x20 Mar 20 21:06:40 usbgentoo kernel: wb_workfn+0x2f6/0x3b0 Mar 20 21:06:40 usbgentoo kernel: ? __switch_to_asm+0x40/0x70 Mar 20 21:06:40 usbgentoo kernel: process_one_work+0x1f5/0x3f0 Mar 20 21:06:40 usbgentoo kernel: worker_thread+0x28/0x3c0 Mar 20 21:06:40 usbgentoo kernel: ? rescuer_thread+0x330/0x330 Mar 20 21:06:40 usbgentoo kernel: kthread+0x10e/0x130 Mar 20 21:06:40 usbgentoo kernel: ? kthread_create_on_node+0x60/0x60 Mar 20 21:06:40 usbgentoo kernel: ret_from_fork+0x35/0x40 The root cause is that we run into an infinite recursive calling in between f2fs_balance_fs_bg and writepage() as described below: - f2fs_write_data_pages --- A - __write_data_page - f2fs_balance_fs - f2fs_balance_fs_bg --- B - f2fs_sync_dirty_inodes - filemap_fdatawrite - f2fs_write_data_pages --- A ... - f2fs_balance_fs_bg --- B ... In order to fix this issue, let's detect such condition in __write_data_page() and just skip calling f2fs_balance_fs() recursively. Reported-by: Hagbard Celine Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/checkpoint.c | 6 ++---- fs/f2fs/data.c | 3 ++- 2 files changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index a98e1b02279e..935ebdb9cf47 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -1009,13 +1009,11 @@ int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi, enum inode_type type) if (inode) { unsigned long cur_ino = inode->i_ino; - if (is_dir) - F2FS_I(inode)->cp_task = current; + F2FS_I(inode)->cp_task = current; filemap_fdatawrite(inode->i_mapping); - if (is_dir) - F2FS_I(inode)->cp_task = NULL; + F2FS_I(inode)->cp_task = NULL; iput(inode); /* We need to give cpu to another writers. */ diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index d87dfa5aa112..9d3c11e09a03 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2038,7 +2038,8 @@ static int __write_data_page(struct page *page, bool *submitted, } unlock_page(page); - if (!S_ISDIR(inode->i_mode) && !IS_NOQUOTA(inode)) + if (!S_ISDIR(inode->i_mode) && !IS_NOQUOTA(inode) && + !F2FS_I(inode)->cp_task) f2fs_balance_fs(sbi, need_balance_fs); if (unlikely(f2fs_cp_error(sbi))) {