Re: [PATCH 1/2] f2fs: split f2fs_allocate_new_segments()

From: Jaegeuk Kim
Date: Mon Jun 29 2020 - 16:20:16 EST


On 06/22, Chao Yu wrote:
> to two independent functions:
> - f2fs_allocate_new_segment() for specified type segment allocation
> - f2fs_allocate_new_segments() for all data type segments allocation
>
> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> ---
> fs/f2fs/f2fs.h | 3 ++-
> fs/f2fs/file.c | 2 +-
> fs/f2fs/recovery.c | 2 +-
> fs/f2fs/segment.c | 39 +++++++++++++++++++++++----------------
> 4 files changed, 27 insertions(+), 19 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 70565d81320b..07290943e91d 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -3327,7 +3327,8 @@ void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi);
> int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
> void f2fs_allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type,
> unsigned int start, unsigned int end);
> -void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi, int type);
> +void f2fs_allocate_new_segment(struct f2fs_sb_info *sbi, int type);
> +void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi);
> int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range);
> bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
> struct cp_control *cpc);
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index f196187159e9..67c65e40b22b 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1659,7 +1659,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
> map.m_seg_type = CURSEG_COLD_DATA_PINNED;
>
> f2fs_lock_op(sbi);
> - f2fs_allocate_new_segments(sbi, CURSEG_COLD_DATA);
> + f2fs_allocate_new_segment(sbi, CURSEG_COLD_DATA_PINNED);

This should be CURSEG_COLD_DATA. Otherwise it causes the below kernel panic.
I fixed this in the -dev, so let me know, if you have other concern.

259 Unable to handle kernel NULL pointer dereference at virtual address 00000008
259 task: 0000000082b4de99 task.stack: 00000000c6b39dbf
259 pc : f2fs_do_write_data_page+0x2b4/0x794
259 lr : f2fs_do_write_data_page+0x290/0x794
259 sp : ffffff800c83b5a0 pstate : 60c00145
259 Call trace:
259 f2fs_do_write_data_page+0x2b4/0x794
259 f2fs_write_single_data_page+0x4a4/0x764
259 f2fs_write_data_pages+0x4dc/0x968
259 do_writepages+0x60/0x124
259 __writeback_single_inode+0xd8/0x490
259 writeback_sb_inodes+0x3a8/0x6e4
259 __writeback_inodes_wb+0xa4/0x14c
259 wb_writeback+0x218/0x434
259 wb_workfn+0x2bc/0x57c
259 process_one_work+0x25c/0x440
259 worker_thread+0x24c/0x480
259 kthread+0x11c/0x12c
259 ret_from_fork+0x10/0x18

> f2fs_unlock_op(sbi);
>
> err = f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_DIO);
> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> index ae5310f02e7f..af974ba273b3 100644
> --- a/fs/f2fs/recovery.c
> +++ b/fs/f2fs/recovery.c
> @@ -742,7 +742,7 @@ static int recover_data(struct f2fs_sb_info *sbi, struct list_head *inode_list,
> f2fs_put_page(page, 1);
> }
> if (!err)
> - f2fs_allocate_new_segments(sbi, NO_CHECK_TYPE);
> + f2fs_allocate_new_segments(sbi);
> return err;
> }
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 113114f98087..f15711e8ee5b 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2707,28 +2707,35 @@ void f2fs_allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type,
> up_read(&SM_I(sbi)->curseg_lock);
> }
>
> -void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi, int type)
> +void __allocate_new_segment(struct f2fs_sb_info *sbi, int type)
> {
> - struct curseg_info *curseg;
> + struct curseg_info *curseg = CURSEG_I(sbi, type);
> unsigned int old_segno;
> - int i;
>
> - down_write(&SIT_I(sbi)->sentry_lock);
> + if (!curseg->next_blkoff &&
> + !get_valid_blocks(sbi, curseg->segno, false) &&
> + !get_ckpt_valid_blocks(sbi, curseg->segno))
> + return;
>
> - for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
> - if (type != NO_CHECK_TYPE && i != type)
> - continue;
> + old_segno = curseg->segno;
> + SIT_I(sbi)->s_ops->allocate_segment(sbi, type, true);
> + locate_dirty_segment(sbi, old_segno);
> +}
>
> - curseg = CURSEG_I(sbi, i);
> - if (type == NO_CHECK_TYPE || curseg->next_blkoff ||
> - get_valid_blocks(sbi, curseg->segno, false) ||
> - get_ckpt_valid_blocks(sbi, curseg->segno)) {
> - old_segno = curseg->segno;
> - SIT_I(sbi)->s_ops->allocate_segment(sbi, i, true);
> - locate_dirty_segment(sbi, old_segno);
> - }
> - }
> +void f2fs_allocate_new_segment(struct f2fs_sb_info *sbi, int type)
> +{
> + down_write(&SIT_I(sbi)->sentry_lock);
> + __allocate_new_segment(sbi, type);
> + up_write(&SIT_I(sbi)->sentry_lock);
> +}
>
> +void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi)
> +{
> + int i;
> +
> + down_write(&SIT_I(sbi)->sentry_lock);
> + for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++)
> + __allocate_new_segment(sbi, i);
> up_write(&SIT_I(sbi)->sentry_lock);
> }
>
> --
> 2.26.2