Messages in this thread | | | Subject | Re: [PATCH] f2fs: fix a race condition between f2fs_write_end_io and f2fs_del_fsync_node_entry | From | Chao Yu <> | Date | Wed, 17 Jun 2020 20:28:16 +0800 |
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On 2020/6/17 17:04, zhaowuyun@wingtech.com wrote: > From: Wuyun Zhao <zhaowuyun@wingtech.com> > > Under some condition, the __write_node_page will submit a page which is not > f2fs_in_warm_node_list and will not call f2fs_add_fsync_node_entry. > f2fs_gc continue to run to invoke f2fs_iget -> do_read_inode to read the same node page > and set code node, which make f2fs_in_warm_node_list become true, > that will cause f2fs_bug_on in f2fs_del_fsync_node_entry when f2fs_write_end_io called. Could you please add below race condition description into commit message?
- f2fs_write_end_io - f2fs_iget - do_read_inode - set_cold_node recover cold node flag - f2fs_in_warm_node_list - is_cold_node if node is cold, assume we have added node to fsync_node_list during writepages() - f2fs_del_fsync_node_entry - f2fs_bug_on() due to node page is not in fsync_node_list
BTW, I'm curious about why we can lose cold flag for non-dir inode? any clue to reproduce this bug (I mean losing cold flag)?
> > [ 34.966133] Call trace: > [ 34.969902] f2fs_del_fsync_node_entry+0x100/0x108 > [ 34.976071] f2fs_write_end_io+0x1e0/0x288 > [ 34.981539] bio_endio+0x248/0x270 > [ 34.986289] blk_update_request+0x2b0/0x4d8 > [ 34.991841] scsi_end_request+0x40/0x440 > [ 34.997126] scsi_io_completion+0xa4/0x748 > [ 35.002593] scsi_finish_command+0xdc/0x110 > [ 35.008143] scsi_softirq_done+0x118/0x150 > [ 35.013610] blk_done_softirq+0x8c/0xe8 > [ 35.018811] __do_softirq+0x2e8/0x578 > [ 35.023828] irq_exit+0xfc/0x120 > [ 35.028398] handle_IPI+0x1d8/0x330 > [ 35.033233] gic_handle_irq+0x110/0x1d4 > [ 35.038433] el1_irq+0xb4/0x130 > [ 35.042917] kmem_cache_alloc+0x3f0/0x418 > [ 35.048288] radix_tree_node_alloc+0x50/0xf8 > [ 35.053933] __radix_tree_create+0xf8/0x188 > [ 35.059484] __radix_tree_insert+0x3c/0x128 > [ 35.065035] add_gc_inode+0x90/0x118 > [ 35.069967] f2fs_gc+0x1b80/0x2d70 > [ 35.074718] f2fs_disable_checkpoint+0x94/0x1d0 > [ 35.080621] f2fs_fill_super+0x10c4/0x1b88 > [ 35.086088] mount_bdev+0x194/0x1e0 > [ 35.090923] f2fs_mount+0x40/0x50 > [ 35.095589] mount_fs+0xb4/0x190 > [ 35.100159] vfs_kern_mount+0x80/0x1d8 > [ 35.105260] do_mount+0x478/0xf18 > [ 35.109926] ksys_mount+0x90/0xd0 > [ 35.114592] __arm64_sys_mount+0x24/0x38 > > Signed-off-by: Wuyun Zhao <zhaowuyun@wingtech.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Thanks,
> --- > fs/f2fs/inode.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c > index be6ac33..0df5c8c 100644 > --- a/fs/f2fs/inode.c > +++ b/fs/f2fs/inode.c > @@ -402,6 +402,7 @@ static int do_read_inode(struct inode *inode) > > /* try to recover cold bit for non-dir inode */ > if (!S_ISDIR(inode->i_mode) && !is_cold_node(node_page)) { > + f2fs_wait_on_page_writeback(node_page, NODE, true, true); > set_cold_node(node_page, false); > set_page_dirty(node_page); > } >
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