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authorChao Yu <yuchao0@huawei.com>2019-04-22 11:33:53 +0200
committerJaegeuk Kim <jaegeuk@kernel.org>2019-05-09 06:23:11 +0200
commitb471eb99e64495a1f0e430da3f96b88f600d3bb5 (patch)
tree39a6ecf494e9fdde22a5947ef36d1ea6c077e2ca /fs/f2fs/f2fs.h
parentf2fs: allow unfixed f2fs_checkpoint.checksum_offset (diff)
downloadlinux-b471eb99e64495a1f0e430da3f96b88f600d3bb5.tar.xz
linux-b471eb99e64495a1f0e430da3f96b88f600d3bb5.zip
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 '')
-rw-r--r--fs/f2fs/f2fs.h6
1 files changed, 5 insertions, 1 deletions
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) {