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authorChao Yu <yuchao0@huawei.com>2019-04-22 17:33:53 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2019-05-08 21:23:11 -0700
commitb471eb99e64495a1f0e430da3f96b88f600d3bb5 (patch)
tree39a6ecf494e9fdde22a5947ef36d1ea6c077e2ca /fs/f2fs
parentd7eb8f1cdfaefcd41b716ef0ed1745b43c6c4fc9 (diff)
downloadlinux-b471eb99e64495a1f0e430da3f96b88f600d3bb5.tar.bz2
f2fs: relocate chksum_offset for large_nat_bitmap feature
For large_nat_bitmap feature, there is a design flaw: Previous: struct f2fs_checkpoint layout: +--------------------------+ 0x0000 | checkpoint_ver | | ...... | | checksum_offset |------+ | ...... | | | sit_nat_version_bitmap[] |<-----|-------+ | ...... | | | | checksum_value |<-----+ | +--------------------------+ 0x1000 | | | nat_bitmap + sit_bitmap | payload blocks | | | | | +--------------------------|<-------------+ Obviously, if nat_bitmap size + sit_bitmap size is larger than MAX_BITMAP_SIZE_IN_CKPT, nat_bitmap or sit_bitmap may overlap checkpoint checksum's position, once checkpoint() is triggered from kernel, nat or sit bitmap will be damaged by checksum field. In order to fix this, let's relocate checksum_value's position to the head of sit_nat_version_bitmap as below, then nat/sit bitmap and chksum value update will become safe. After: struct f2fs_checkpoint layout: +--------------------------+ 0x0000 | checkpoint_ver | | ...... | | checksum_offset |------+ | ...... | | | sit_nat_version_bitmap[] |<-----+ | ...... |<-------------+ | | | +--------------------------+ 0x1000 | | | nat_bitmap + sit_bitmap | payload blocks | | | | | +--------------------------|<-------------+ Related report and discussion: https://sourceforge.net/p/linux-f2fs/mailman/message/36642346/ Reported-by: Park Ju Hyung <qkrwngud825@gmail.com> Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs')
-rw-r--r--fs/f2fs/checkpoint.c11
-rw-r--r--fs/f2fs/f2fs.h6
2 files changed, 16 insertions, 1 deletions
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index af77655e65b2..d52a15799488 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -795,6 +795,17 @@ static int get_checkpoint_version(struct f2fs_sb_info *sbi, block_t cp_addr,
return -EINVAL;
}
+ if (__is_set_ckpt_flags(*cp_block, CP_LARGE_NAT_BITMAP_FLAG)) {
+ if (crc_offset != CP_MIN_CHKSUM_OFFSET) {
+ f2fs_put_page(*cp_page, 1);
+ f2fs_msg(sbi->sb, KERN_WARNING,
+ "layout of large_nat_bitmap is deprecated, "
+ "run fsck to repair, chksum_offset: %zu",
+ crc_offset);
+ return -EINVAL;
+ }
+ }
+
crc = f2fs_checkpoint_chksum(sbi, *cp_block);
if (crc != cur_cp_crc(*cp_block)) {
f2fs_put_page(*cp_page, 1);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9a9dc20e295b..97e4ef71de64 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1910,7 +1910,11 @@ static inline void *__bitmap_ptr(struct f2fs_sb_info *sbi, int flag)
if (is_set_ckpt_flags(sbi, CP_LARGE_NAT_BITMAP_FLAG)) {
offset = (flag == SIT_BITMAP) ?
le32_to_cpu(ckpt->nat_ver_bitmap_bytesize) : 0;
- return &ckpt->sit_nat_version_bitmap + offset;
+ /*
+ * if large_nat_bitmap feature is enabled, leave checksum
+ * protection for all nat/sit bitmaps.
+ */
+ return &ckpt->sit_nat_version_bitmap + offset + sizeof(__le32);
}
if (__cp_payload(sbi) > 0) {