We may encounter both checkpoints invalid in such a case:
1. write checkpoint A, B, C;
2. sudden power-cut during write checkpoint D;
3. fsck changes the total block count of checkpoint C;
4. sudden power-cut during fsck write checkpoint C in place
--------- ---------
| ver C | | ver D |
| ... | | ... |
| content | | content |
| ... | | ... |
| ver C | | |
| ver A | | ver B |
--------- ---------
As the total # of checkpoint C is changed, an old cp block
like ver A or an invalid cp block may be referenced.
To avoid both checkpoints invalid, and considering fsck should
not update the checkpoint version, fsck could write checkpoint
out of place first and then write checkpoint in place. This
makes sure the file system is fixed by fsck and at least one
of the two checkpoints is valid.
Signed-off-by: Weichao Guo <guoweic...@huawei.com>
---
fsck/defrag.c | 2 +-
fsck/fsck.c | 14 +++++++++++++-
fsck/fsck.h | 1 +
fsck/mount.c | 16 ++++++++++++++--
fsck/sload.c | 2 +-
5 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/fsck/defrag.c b/fsck/defrag.c
index bea0293..9fc932f 100644
--- a/fsck/defrag.c
+++ b/fsck/defrag.c
@@ -96,7 +96,7 @@ int f2fs_defragment(struct f2fs_sb_info *sbi, u64 from, u64
len, u64 to, int lef
/* flush dirty sit entries */
flush_sit_entries(sbi);
- write_checkpoint(sbi);
+ __write_checkpoint(sbi);
return 0;
}
diff --git a/fsck/fsck.c b/fsck/fsck.c
index 91c8529..f2ff4bc 100644
--- a/fsck/fsck.c
+++ b/fsck/fsck.c
@@ -1943,7 +1943,7 @@ static void flush_curseg_sit_entries(struct f2fs_sb_info
*sbi)
free(sit_blk);
}
-static void fix_checkpoint(struct f2fs_sb_info *sbi)
+static void __fix_checkpoint(struct f2fs_sb_info *sbi)
{
struct f2fs_fsck *fsck = F2FS_FSCK(sbi);
struct f2fs_super_block *sb = F2FS_RAW_SUPER(sbi);
@@ -2004,6 +2004,18 @@ static void fix_checkpoint(struct f2fs_sb_info *sbi)
write_nat_bits(sbi, sb, cp, sbi->cur_cp);
}
+static void fix_checkpoint(struct f2fs_sb_info *sbi)
+{
+ int i = 0;
+
+ for (i = 0; i < 2; i++) {
+ /* write checkpoint out of place first */
+ sbi->cur_cp = sbi->cur_cp % 2 + 1;
+ __fix_checkpoint(sbi);
+ f2fs_fsync_device();
+ }
+}
+
int check_curseg_offset(struct f2fs_sb_info *sbi)
{
int i;
diff --git a/fsck/fsck.h b/fsck/fsck.h
index 8e133fa..068dd34 100644
--- a/fsck/fsck.h
+++ b/fsck/fsck.h
@@ -175,6 +175,7 @@ extern void flush_sit_entries(struct f2fs_sb_info *);
extern void move_curseg_info(struct f2fs_sb_info *, u64);
extern void write_curseg_info(struct f2fs_sb_info *);
extern int find_next_free_block(struct f2fs_sb_info *, u64 *, int, int);
+extern void __write_checkpoint(struct f2fs_sb_info *);
extern void write_checkpoint(struct f2fs_sb_info *);
extern void update_data_blkaddr(struct f2fs_sb_info *, nid_t, u16, block_t);
extern void update_nat_blkaddr(struct f2fs_sb_info *, nid_t, nid_t, block_t);
diff --git a/fsck/mount.c b/fsck/mount.c
index e5574c5..8a29421 100644
--- a/fsck/mount.c
+++ b/fsck/mount.c
@@ -1856,7 +1856,7 @@ void flush_journal_entries(struct f2fs_sb_info *sbi)
int n_sits = flush_sit_journal_entries(sbi);
if (n_nats || n_sits)
- write_checkpoint(sbi);
+ __write_checkpoint(sbi);
}
void flush_sit_entries(struct f2fs_sb_info *sbi)
@@ -2079,7 +2079,7 @@ void nullify_nat_entry(struct f2fs_sb_info *sbi, u32 nid)
free(nat_block);
}
-void write_checkpoint(struct f2fs_sb_info *sbi)
+void __write_checkpoint(struct f2fs_sb_info *sbi)
{
struct f2fs_checkpoint *cp = F2FS_CKPT(sbi);
struct f2fs_super_block *sb = F2FS_RAW_SUPER(sbi);
@@ -2144,6 +2144,18 @@ void write_checkpoint(struct f2fs_sb_info *sbi)
ASSERT(ret >= 0);
}
+void write_checkpoint(struct f2fs_sb_info *sbi)
+{
+ int i = 0;
+
+ for (i = 0; i < 2; i++) {
+ /* write checkpoint out of place first */
+ sbi->cur_cp = sbi->cur_cp % 2 + 1;
+ __write_checkpoint(sbi);
+ f2fs_fsync_device();
+ }
+}
+
void build_nat_area_bitmap(struct f2fs_sb_info *sbi)
{
struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
diff --git a/fsck/sload.c b/fsck/sload.c
index 2842f2c..53d80fa 100644
--- a/fsck/sload.c
+++ b/fsck/sload.c
@@ -325,6 +325,6 @@ int f2fs_sload(struct f2fs_sb_info *sbi)
/* flush dirty sit entries */
flush_sit_entries(sbi);
- write_checkpoint(sbi);
+ __write_checkpoint(sbi);
return 0;
}
--
2.10.1
------------------------------------------------------------------------------
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