[f2fs-dev] [PATCH v2 1/2] Revert "resize.f2fs: add option for large_nat_bitmap feature"

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

This reverts commit daa0f8b9e9b1eea6c85e5c169b809254d9d7074e.

As Juhyung reported in [1]:

Here's what I did:
1. Remounted to checkpoint=disable
2. Create a dm-snapshot of the current root device
3. Mount snapshot to replay the log
4. Unmount
5. Resize sector 487248896 to 486539264
// ./resize.f2fs -d 3 -s -i /dev/mapper/snap -t 486539264

Latest f2fs-tools was used:
33c5b9539af2 f2fs_io: add fragread command to evaluate fragmented
buffer for reads

This reproduced the mount and fsck failure.

Mount log:
[442431.020594] F2FS-fs (dm-2): invalid crc_offset: 0
[442431.130055] F2FS-fs (dm-2): SIT is corrupted node# 13615201 vs 13616290
[442431.139684] F2FS-fs (dm-2): Failed to initialize F2FS segment manager (-117)

I checked below testcases:

truncate -s $((512*1024*1024*1024)) img
mkfs.f2fs -f img $((256*1024*1024))

Description		Test command					FSCK output
a) shrink w/ -s		resize.f2fs -s -i img -t $((128*1024*1024))	Fine
b) expand w/ -s		resize.f2fs -s -i img -t $((1024*1024*1024))	Corrupted
c) shrink w/o -s	resize.f2fs -i img -t $((128*1024*1024))	No run
d) expand w/o -s	resize.f2fs -i img -t $((1024*1024*1024))	Fine

Output from b):
[ASSERT] (check_block_count:2299)  --> Wrong SIT valid blocks: segno=0x29400, 0 vs. 13

The root cause is: safe mode (-s option) is conflict w/ large nat bitmap feature
(-i option), since once we enable large nat bitmap, layout of checkpoint will be
changed [2], we must relocate nat/sit_bitmap to the end of new location of
cp_checksum, however in safe mode, we won't change metadata of checkpoint, so we
need to keep nat/sit_bitmap as it is, which includes checksum data in its old
location.

Let's revert -i support for resize.f2fs first, and then reenable it after
fix and well tested.

Thanks a lot for the help from Juhyung, including providing reproducer and
hints.

[1] https://lore.kernel.org/linux-f2fs-devel/CAD14+f3D6iPOBxEgkZxxTsXCfwRKb9ph68JtUk3H9cn8ovLt9w@mail.gmail.com/
[2] https://lore.kernel.org/linux-f2fs-devel/20190514093340.40217-2-yuchao0@huawei.com/

Fixes: daa0f8b ("resize.f2fs: add option for large_nat_bitmap feature")
Reported-by: Ju Hyung Park <qkrwngud825@gmail.com>
Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- remove entry in manual page
 fsck/main.c       | 6 +-----
 fsck/resize.c     | 3 ---
 man/resize.f2fs.8 | 6 ------
 3 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/fsck/main.c b/fsck/main.c
index 524dbb1..af40613 100644
--- a/fsck/main.c
+++ b/fsck/main.c
@@ -141,7 +141,6 @@ void resize_usage()
 	MSG(0, "[options]:\n");
 	MSG(0, "  -d debug level [default:0]\n");
 	MSG(0, "  -H support write hint\n");
-	MSG(0, "  -i extended node bitmap, node ratio is 20%% by default\n");
 	MSG(0, "  -o overprovision percentage [default:auto]\n");
 	MSG(0, "  -s safe resize (Does not resize metadata)\n");
 	MSG(0, "  -t target sectors [default: device size]\n");
@@ -602,7 +601,7 @@ void f2fs_parse_options(int argc, char *argv[])
 #endif
 	} else if (!strcmp("resize.f2fs", prog)) {
 #ifdef WITH_RESIZE
-		const char *option_string = "d:fHst:io:V";
+		const char *option_string = "d:fHst:o:V";
 
 		c.func = RESIZE;
 		while ((option = getopt(argc, argv, option_string)) != EOF) {
@@ -637,9 +636,6 @@ void f2fs_parse_options(int argc, char *argv[])
 					ret = sscanf(optarg, "%"PRIx64"",
 							&c.target_sectors);
 				break;
-			case 'i':
-				c.large_nat_bitmap = 1;
-				break;
 			case 'o':
 				c.new_overprovision = atof(optarg);
 				break;
diff --git a/fsck/resize.c b/fsck/resize.c
index 9b3b071..2681b9f 100644
--- a/fsck/resize.c
+++ b/fsck/resize.c
@@ -531,9 +531,6 @@ static void rebuild_checkpoint(struct f2fs_sb_info *sbi,
 
 	/* update nat_bits flag */
 	flags = update_nat_bits_flags(new_sb, cp, get_cp(ckpt_flags));
-	if (c.large_nat_bitmap)
-		flags |= CP_LARGE_NAT_BITMAP_FLAG;
-
 	if (flags & CP_COMPACT_SUM_FLAG)
 		flags &= ~CP_COMPACT_SUM_FLAG;
 	if (flags & CP_LARGE_NAT_BITMAP_FLAG)
diff --git a/man/resize.f2fs.8 b/man/resize.f2fs.8
index d41ad79..02ff245 100644
--- a/man/resize.f2fs.8
+++ b/man/resize.f2fs.8
@@ -21,9 +21,6 @@ resize.f2fs \- resize filesystem size
 .B \-H
 ]
 [
-.B \-i
-]
-[
 .B \-s
 ]
 [
@@ -59,9 +56,6 @@ best number will be assigned automatically according to the partition size.
 .BI \-H
 Specify support write hint.
 .TP
-.BI \-i
-Enable extended node bitmap.
-.TP
 .BI \-s
 Enable safe resize.
 .TP
-- 
2.40.1



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