From ae643a74ebdb150b004601d0d5fe5a1faba9b04d Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Sun, 22 May 2022 13:47:48 +0200 Subject: [PATCH] btrfs: introduce a data checksum checking helper Although we have several data csum verification code, we never have a function really just to verify checksum for one sector. Function check_data_csum() do extra work for error reporting, thus it requires a lot of extra things like file offset, bio_offset etc. Function btrfs_verify_data_csum() is even worse, it will utilize page checked flag, which means it can not be utilized for direct IO pages. Here we introduce a new helper, btrfs_check_sector_csum(), which really only accept a sector in page, and expected checksum pointer. We use this function to implement check_data_csum(), and export it for incoming patch. Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo [hch: keep passing the csum array as an arguments, as the callers want to print it, rename per request] Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/compression.c | 13 ++++--------- fs/btrfs/ctree.h | 2 ++ fs/btrfs/inode.c | 38 ++++++++++++++++++++++++++++---------- 3 files changed, 34 insertions(+), 19 deletions(-) diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index f4564f3..6ab82e14 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -147,12 +147,10 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio, u64 disk_start) { struct btrfs_fs_info *fs_info = inode->root->fs_info; - SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); const u32 csum_size = fs_info->csum_size; const u32 sectorsize = fs_info->sectorsize; struct page *page; unsigned int i; - char *kaddr; u8 csum[BTRFS_CSUM_SIZE]; struct compressed_bio *cb = bio->bi_private; u8 *cb_sum = cb->sums; @@ -161,8 +159,6 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio, test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state)) return 0; - shash->tfm = fs_info->csum_shash; - for (i = 0; i < cb->nr_pages; i++) { u32 pg_offset; u32 bytes_left = PAGE_SIZE; @@ -175,12 +171,11 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio, /* Hash through the page sector by sector */ for (pg_offset = 0; pg_offset < bytes_left; pg_offset += sectorsize) { - kaddr = kmap_atomic(page); - crypto_shash_digest(shash, kaddr + pg_offset, - sectorsize, csum); - kunmap_atomic(kaddr); + int ret; - if (memcmp(&csum, cb_sum, csum_size) != 0) { + ret = btrfs_check_sector_csum(fs_info, page, pg_offset, + csum, cb_sum); + if (ret) { btrfs_print_data_csum_error(inode, disk_start, csum, cb_sum, cb->mirror_num); if (btrfs_bio(bio)->device) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index ad31cc5..6e65778 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3253,6 +3253,8 @@ u64 btrfs_file_extent_end(const struct btrfs_path *path); /* inode.c */ void btrfs_submit_data_bio(struct inode *inode, struct bio *bio, int mirror_num, enum btrfs_compression_type compress_type); +int btrfs_check_sector_csum(struct btrfs_fs_info *fs_info, struct page *page, + u32 pgoff, u8 *csum, const u8 * const csum_expected); unsigned int btrfs_verify_data_csum(struct btrfs_bio *bbio, u32 bio_offset, struct page *page, u64 start, u64 end); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 332b8f1..193931b 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3329,6 +3329,29 @@ void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode, } /* + * Verify the checksum for a single sector without any extra action that depend + * on the type of I/O. + */ +int btrfs_check_sector_csum(struct btrfs_fs_info *fs_info, struct page *page, + u32 pgoff, u8 *csum, const u8 * const csum_expected) +{ + SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); + char *kaddr; + + ASSERT(pgoff + fs_info->sectorsize <= PAGE_SIZE); + + shash->tfm = fs_info->csum_shash; + + kaddr = kmap_local_page(page) + pgoff; + crypto_shash_digest(shash, kaddr, fs_info->sectorsize, csum); + kunmap_local(kaddr); + + if (memcmp(csum, csum_expected, fs_info->csum_size)) + return -EIO; + return 0; +} + +/* * check_data_csum - verify checksum of one sector of uncompressed data * @inode: inode * @io_bio: btrfs_io_bio which contains the csum @@ -3338,14 +3361,15 @@ void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode, * @start: logical offset in the file * * The length of such check is always one sector size. + * + * When csum mismatch is detected, we will also report the error and fill the + * corrupted range with zero. (Thus it needs the extra parameters) */ static int check_data_csum(struct inode *inode, struct btrfs_bio *bbio, u32 bio_offset, struct page *page, u32 pgoff, u64 start) { struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); - SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); - char *kaddr; u32 len = fs_info->sectorsize; const u32 csum_size = fs_info->csum_size; unsigned int offset_sectors; @@ -3357,16 +3381,10 @@ static int check_data_csum(struct inode *inode, struct btrfs_bio *bbio, offset_sectors = bio_offset >> fs_info->sectorsize_bits; csum_expected = ((u8 *)bbio->csum) + offset_sectors * csum_size; - kaddr = kmap_atomic(page); - shash->tfm = fs_info->csum_shash; - - crypto_shash_digest(shash, kaddr + pgoff, len, csum); - kunmap_atomic(kaddr); - - if (memcmp(csum, csum_expected, csum_size)) + if (btrfs_check_sector_csum(fs_info, page, pgoff, csum, csum_expected)) goto zeroit; - return 0; + zeroit: btrfs_print_data_csum_error(BTRFS_I(inode), start, csum, csum_expected, bbio->mirror_num); -- 2.7.4