[PATCH 2/2] f2fs: introduce written_map to indicate written datas

Chao Yu
2024-04-07T13:02:03Z

Currently, __exchange_data_block() will check checkpointed state of data,
if it is not checkpointed, it will try to exchange blkaddrs directly in
dnode.

However, after commit 899fee36fac0 ("f2fs: fix to avoid data corruption
by forbidding SSR overwrite"), in order to disallow SSR allocator to
reuse all written data/node type blocks, all written blocks were set as
checkpointed.

In order to reenable metadata exchange functionality, let's introduce
written_map to indicate all written blocks including checkpointed one,
or newly written and invalidated one, and use it for SSR allocation,
and then ckpt_valid_bitmap can indicate real checkpointed status, and
we can use it correctly in __exchange_data_block().

[testcase]
xfs_io -f /mnt/f2fs/src -c "pwrite 0 2m"
xfs_io -f /mnt/f2fs/dst -c "pwrite 0 2m"
xfs_io /mnt/f2fs/src -c "fiemap -v"
xfs_io /mnt/f2fs/dst -c "fiemap -v"
f2fs_io move_range /mnt/f2fs/src /mnt/f2fs/dst 0 0 2097152
xfs_io /mnt/f2fs/src -c "fiemap -v"
xfs_io /mnt/f2fs/dst -c "fiemap -v"

[before]
/mnt/f2fs/src:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..4095]: 8445952..8450047 4096 0x1001
/mnt/f2fs/dst:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..4095]: 143360..147455 4096 0x1001

/mnt/f2fs/src:
/mnt/f2fs/dst:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..4095]: 4284416..4288511 4096 0x1001

[after]
/mnt/f2fs/src:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..4095]: 147456..151551 4096 0x1001
/mnt/f2fs/dst:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..4095]: 151552..155647 4096 0x1001

/mnt/f2fs/src:
/mnt/f2fs/dst:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..4095]: 147456..151551 4096 0x1001

Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/f2fs/segment.c | 24 ++++++++++++------------
fs/f2fs/segment.h | 6 ++++++
2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index ecb9ee80d5e0..ec3288381397 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2456,13 +2456,12 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
sbi->discard_blks--;

/*
- * SSR should never reuse block which is checkpointed
- * or newly invalidated.
+ * if CP disabling is enable, it allows SSR to reuse newly
+ * invalidated block, otherwise forbidding it to pretect fsyned
+ * datas.
*/
- if (!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
- if (!f2fs_test_and_set_bit(offset, se->ckpt_valid_map))
- se->ckpt_valid_blocks++;
- }
+ if (!is_sbi_flag_set(sbi, SBI_CP_DISABLED))
+ f2fs_set_bit(offset, se->written_map);
} else {
exist = f2fs_test_and_clear_bit(offset, se->cur_valid_map);
#ifdef CONFIG_F2FS_CHECK_FS
@@ -2498,8 +2497,6 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
f2fs_test_and_clear_bit(offset, se->discard_map))
sbi->discard_blks++;
}
- if (!f2fs_test_bit(offset, se->ckpt_valid_map))
- se->ckpt_valid_blocks += del;

__mark_sit_entry_dirty(sbi, segno);

@@ -2847,11 +2844,11 @@ static void __get_segment_bitmap(struct f2fs_sb_info *sbi,
struct seg_entry *se = get_seg_entry(sbi, segno);
int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
- unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
+ unsigned long *written_map = (unsigned long *)se->written_map;
int i;

for (i = 0; i < entries; i++)
- target_map[i] = ckpt_map[i] | cur_map[i];
+ target_map[i] = ckpt_map[i] | written_map[i];
}

static int __next_free_blkoff(struct f2fs_sb_info *sbi, unsigned long *bitmap,
@@ -4529,9 +4526,9 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
return -ENOMEM;

#ifdef CONFIG_F2FS_CHECK_FS
- bitmap_size = MAIN_SEGS(sbi) * SIT_VBLOCK_MAP_SIZE * (3 + discard_map);
+ bitmap_size = MAIN_SEGS(sbi) * SIT_VBLOCK_MAP_SIZE * (4 + discard_map);
#else
- bitmap_size = MAIN_SEGS(sbi) * SIT_VBLOCK_MAP_SIZE * (2 + discard_map);
+ bitmap_size = MAIN_SEGS(sbi) * SIT_VBLOCK_MAP_SIZE * (3 + discard_map);
#endif
sit_i->bitmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
if (!sit_i->bitmap)
@@ -4546,6 +4543,9 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
sit_i->sentries[start].ckpt_valid_map = bitmap;
bitmap += SIT_VBLOCK_MAP_SIZE;

+ sit_i->sentries[start].written_map = bitmap;
+ bitmap += SIT_VBLOCK_MAP_SIZE;
+
#ifdef CONFIG_F2FS_CHECK_FS
sit_i->sentries[start].cur_valid_map_mir = bitmap;
bitmap += SIT_VBLOCK_MAP_SIZE;
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 08d667e6a36f..eda04d9ed5a5 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -205,6 +205,10 @@ struct seg_entry {
* checkpoint pack. This information is used by the SSR mode.
*/
unsigned char *ckpt_valid_map; /* validity bitmap of blocks last cp */
+ unsigned char *written_map; /*
+ * blocks were written, including newly
+ * invalidated data
+ */
unsigned char *discard_map;
unsigned long long mtime; /* modification time of the segment */
};
@@ -370,6 +374,7 @@ static inline void seg_info_from_raw_sit(struct seg_entry *se,
se->ckpt_valid_blocks = GET_SIT_VBLOCKS(rs);
memcpy(se->cur_valid_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
memcpy(se->ckpt_valid_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
+ memcpy(se->written_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
#ifdef CONFIG_F2FS_CHECK_FS
memcpy(se->cur_valid_map_mir, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
#endif
@@ -412,6 +417,7 @@ static inline void seg_info_to_raw_sit(struct seg_entry *se,
__seg_info_to_raw_sit(se, rs);

memcpy(se->ckpt_valid_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
+ memcpy(se->written_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
se->ckpt_valid_blocks = se->valid_blocks;
}

--
2.40.1