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Message-ID: <20181129033239.GE9838@codeaurora.org>
Date: Thu, 29 Nov 2018 09:02:39 +0530
From: Sahitya Tummala <stummala@...eaurora.org>
To: Chao Yu <yuchao0@...wei.com>
Cc: Jaegeuk Kim <jaegeuk@...nel.org>,
linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] f2fs: fix sbi->extent_list corruption issue
On Tue, Nov 27, 2018 at 09:42:39AM +0800, Chao Yu wrote:
> On 2018/11/27 8:30, Jaegeuk Kim wrote:
> > On 11/26, Sahitya Tummala wrote:
> >> When there is a failure in f2fs_fill_super() after/during
> >> the recovery of fsync'd nodes, it frees the current sbi and
> >> retries again. This time the mount is successful, but the files
> >> that got recovered before retry, still holds the extent tree,
> >> whose extent nodes list is corrupted since sbi and sbi->extent_list
> >> is freed up. The list_del corruption issue is observed when the
> >> file system is getting unmounted and when those recoverd files extent
> >> node is being freed up in the below context.
> >>
> >> list_del corruption. prev->next should be fffffff1e1ef5480, but was (null)
> >> <...>
> >> kernel BUG at kernel/msm-4.14/lib/list_debug.c:53!
> >> task: fffffff1f46f2280 task.stack: ffffff8008068000
> >> lr : __list_del_entry_valid+0x94/0xb4
> >> pc : __list_del_entry_valid+0x94/0xb4
> >> <...>
> >> Call trace:
> >> __list_del_entry_valid+0x94/0xb4
> >> __release_extent_node+0xb0/0x114
> >> __free_extent_tree+0x58/0x7c
> >> f2fs_shrink_extent_tree+0xdc/0x3b0
> >> f2fs_leave_shrinker+0x28/0x7c
> >> f2fs_put_super+0xfc/0x1e0
> >> generic_shutdown_super+0x70/0xf4
> >> kill_block_super+0x2c/0x5c
> >> kill_f2fs_super+0x44/0x50
> >> deactivate_locked_super+0x60/0x8c
> >> deactivate_super+0x68/0x74
> >> cleanup_mnt+0x40/0x78
> >> __cleanup_mnt+0x1c/0x28
> >> task_work_run+0x48/0xd0
> >> do_notify_resume+0x678/0xe98
> >> work_pending+0x8/0x14
> >>
> >> Fix this by cleaning up inodes, extent tree and nodes of those
> >> recovered files before freeing up sbi and before next retry.
> >>
> >> Signed-off-by: Sahitya Tummala <stummala@...eaurora.org>
> >> ---
> >> v2:
> >> -call evict_inodes() and f2fs_shrink_extent_tree() to cleanup inodes
> >>
> >> fs/f2fs/f2fs.h | 1 +
> >> fs/f2fs/shrinker.c | 2 +-
> >> fs/f2fs/super.c | 13 ++++++++++++-
> >> 3 files changed, 14 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >> index 1e03197..aaee63b 100644
> >> --- a/fs/f2fs/f2fs.h
> >> +++ b/fs/f2fs/f2fs.h
> >> @@ -3407,6 +3407,7 @@ struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
> >> bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
> >> struct rb_root_cached *root);
> >> unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink);
> >> +unsigned long __count_extent_cache(struct f2fs_sb_info *sbi);
> >> bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext);
> >> void f2fs_drop_extent_tree(struct inode *inode);
> >> unsigned int f2fs_destroy_extent_node(struct inode *inode);
> >> diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
> >> index 9e13db9..7e3c13b 100644
> >> --- a/fs/f2fs/shrinker.c
> >> +++ b/fs/f2fs/shrinker.c
> >> @@ -30,7 +30,7 @@ static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
> >> return count > 0 ? count : 0;
> >> }
> >>
> >> -static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
> >> +unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
> >> {
> >> return atomic_read(&sbi->total_zombie_tree) +
> >> atomic_read(&sbi->total_ext_node);
> >> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> >> index af58b2c..769e7b1 100644
> >> --- a/fs/f2fs/super.c
> >> +++ b/fs/f2fs/super.c
> >> @@ -3016,6 +3016,16 @@ static void f2fs_tuning_parameters(struct f2fs_sb_info *sbi)
> >> sbi->readdir_ra = 1;
> >> }
> >>
> >> +static void f2fs_cleanup_inodes(struct f2fs_sb_info *sbi)
> >> +{
> >> + struct super_block *sb = sbi->sb;
> >> +
> >> + sync_filesystem(sb);
> >
> > This writes another checkpoint, which would not be what this retrial intended.
>
> Actually, checkpoint will not be triggered due to SBI_POR_DOING flag check
> as below:
>
> int f2fs_sync_fs(struct super_block *sb, int sync)
> {
> ...
> if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
> return -EAGAIN;
> ...
> }
>
> And also all dirty data/node won't be persisted due to SBI_POR_DOING flag,
> IIUC.
>
Thanks Chao for the clarification.
Hi Jaegeuk,
Do you still have any further concerns or comments on this patch?
Thanks,
Sahitya.
> Thanks,
>
> > How about adding a condition in f2fs_may_extent_tree() when adding extents?
> > Likewise, if (shrinker is not registered) return false;
> >
> >
> >> + shrink_dcache_sb(sb);
> >> + evict_inodes(sb);
> >> + f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi));
> >> +}
> >> +
> >> static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> >> {
> >> struct f2fs_sb_info *sbi;
> >> @@ -3402,6 +3412,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> >> * falls into an infinite loop in f2fs_sync_meta_pages().
> >> */
> >> truncate_inode_pages_final(META_MAPPING(sbi));
> >> + /* cleanup recovery and quota inodes */
> >> + f2fs_cleanup_inodes(sbi);
> >> f2fs_unregister_sysfs(sbi);
> >> free_root_inode:
> >> dput(sb->s_root);
> >> @@ -3445,7 +3457,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> >> /* give only one another chance */
> >> if (retry) {
> >> retry = false;
> >> - shrink_dcache_sb(sb);
> >> goto try_onemore;
> >> }
> >> return err;
> >> --
> >> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
> >
> > .
> >
>
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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