1 files changed, 43 insertions, 110 deletions

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 016a025e36c7..5a6cb9db512e 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1616,13 +1616,9 @@ static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
 	struct scrub_page *spage = sblock->pagev[page_num];
 
 	BUG_ON(spage->page == NULL);
-	if (spage->io_error) {
-		void *mapped_buffer = kmap_atomic(spage->page);
+	if (spage->io_error)
+		clear_page(page_address(spage->page));
 
-		clear_page(mapped_buffer);
-		flush_dcache_page(spage->page);
-		kunmap_atomic(mapped_buffer);
-	}
 	return scrub_add_page_to_wr_bio(sblock->sctx, spage);
 }
 
@@ -1790,42 +1786,21 @@ static int scrub_checksum_data(struct scrub_block *sblock)
 	struct btrfs_fs_info *fs_info = sctx->fs_info;
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	u8 csum[BTRFS_CSUM_SIZE];
-	u8 *on_disk_csum;
-	struct page *page;
-	void *buffer;
-	u64 len;
-	int index;
+	struct scrub_page *spage;
+	char *kaddr;
 
 	BUG_ON(sblock->page_count < 1);
-	if (!sblock->pagev[0]->have_csum)
+	spage = sblock->pagev[0];
+	if (!spage->have_csum)
 		return 0;
 
+	kaddr = page_address(spage->page);
+
 	shash->tfm = fs_info->csum_shash;
 	crypto_shash_init(shash);
+	crypto_shash_digest(shash, kaddr, PAGE_SIZE, csum);
 
-	on_disk_csum = sblock->pagev[0]->csum;
-	page = sblock->pagev[0]->page;
-	buffer = kmap_atomic(page);
-
-	len = sctx->fs_info->sectorsize;
-	index = 0;
-	for (;;) {
-		u64 l = min_t(u64, len, PAGE_SIZE);
-
-		crypto_shash_update(shash, buffer, l);
-		kunmap_atomic(buffer);
-		len -= l;
-		if (len == 0)
-			break;
-		index++;
-		BUG_ON(index >= sblock->page_count);
-		BUG_ON(!sblock->pagev[index]->page);
-		page = sblock->pagev[index]->page;
-		buffer = kmap_atomic(page);
-	}
-
-	crypto_shash_final(shash, csum);
-	if (memcmp(csum, on_disk_csum, sctx->csum_size))
+	if (memcmp(csum, spage->csum, sctx->csum_size))
 		sblock->checksum_error = 1;
 
 	return sblock->checksum_error;
@@ -1839,20 +1814,15 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock)
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	u8 calculated_csum[BTRFS_CSUM_SIZE];
 	u8 on_disk_csum[BTRFS_CSUM_SIZE];
-	struct page *page;
-	void *mapped_buffer;
-	u64 mapped_size;
-	void *p;
-	u64 len;
-	int index;
-
-	shash->tfm = fs_info->csum_shash;
-	crypto_shash_init(shash);
+	const int num_pages = sctx->fs_info->nodesize >> PAGE_SHIFT;
+	int i;
+	struct scrub_page *spage;
+	char *kaddr;
 
 	BUG_ON(sblock->page_count < 1);
-	page = sblock->pagev[0]->page;
-	mapped_buffer = kmap_atomic(page);
-	h = (struct btrfs_header *)mapped_buffer;
+	spage = sblock->pagev[0];
+	kaddr = page_address(spage->page);
+	h = (struct btrfs_header *)kaddr;
 	memcpy(on_disk_csum, h->csum, sctx->csum_size);
 
 	/*
@@ -1860,40 +1830,29 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock)
 	 * a) don't have an extent buffer and
 	 * b) the page is already kmapped
 	 */
-	if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
+	if (spage->logical != btrfs_stack_header_bytenr(h))
 		sblock->header_error = 1;
 
-	if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h)) {
+	if (spage->generation != btrfs_stack_header_generation(h)) {
 		sblock->header_error = 1;
 		sblock->generation_error = 1;
 	}
 
-	if (!scrub_check_fsid(h->fsid, sblock->pagev[0]))
+	if (!scrub_check_fsid(h->fsid, spage))
 		sblock->header_error = 1;
 
 	if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
 		   BTRFS_UUID_SIZE))
 		sblock->header_error = 1;
 
-	len = sctx->fs_info->nodesize - BTRFS_CSUM_SIZE;
-	mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
-	p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
-	index = 0;
-	for (;;) {
-		u64 l = min_t(u64, len, mapped_size);
+	shash->tfm = fs_info->csum_shash;
+	crypto_shash_init(shash);
+	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
+			    PAGE_SIZE - BTRFS_CSUM_SIZE);
 
-		crypto_shash_update(shash, p, l);
-		kunmap_atomic(mapped_buffer);
-		len -= l;
-		if (len == 0)
-			break;
-		index++;
-		BUG_ON(index >= sblock->page_count);
-		BUG_ON(!sblock->pagev[index]->page);
-		page = sblock->pagev[index]->page;
-		mapped_buffer = kmap_atomic(page);
-		mapped_size = PAGE_SIZE;
-		p = mapped_buffer;
+	for (i = 1; i < num_pages; i++) {
+		kaddr = page_address(sblock->pagev[i]->page);
+		crypto_shash_update(shash, kaddr, PAGE_SIZE);
 	}
 
 	crypto_shash_final(shash, calculated_csum);
@@ -1910,57 +1869,31 @@ static int scrub_checksum_super(struct scrub_block *sblock)
 	struct btrfs_fs_info *fs_info = sctx->fs_info;
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	u8 calculated_csum[BTRFS_CSUM_SIZE];
-	u8 on_disk_csum[BTRFS_CSUM_SIZE];
-	struct page *page;
-	void *mapped_buffer;
-	u64 mapped_size;
-	void *p;
+	struct scrub_page *spage;
+	char *kaddr;
 	int fail_gen = 0;
 	int fail_cor = 0;
-	u64 len;
-	int index;
-
-	shash->tfm = fs_info->csum_shash;
-	crypto_shash_init(shash);
 
 	BUG_ON(sblock->page_count < 1);
-	page = sblock->pagev[0]->page;
-	mapped_buffer = kmap_atomic(page);
-	s = (struct btrfs_super_block *)mapped_buffer;
-	memcpy(on_disk_csum, s->csum, sctx->csum_size);
+	spage = sblock->pagev[0];
+	kaddr = page_address(spage->page);
+	s = (struct btrfs_super_block *)kaddr;
 
-	if (sblock->pagev[0]->logical != btrfs_super_bytenr(s))
+	if (spage->logical != btrfs_super_bytenr(s))
 		++fail_cor;
 
-	if (sblock->pagev[0]->generation != btrfs_super_generation(s))
+	if (spage->generation != btrfs_super_generation(s))
 		++fail_gen;
 
-	if (!scrub_check_fsid(s->fsid, sblock->pagev[0]))
+	if (!scrub_check_fsid(s->fsid, spage))
 		++fail_cor;
 
-	len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
-	mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
-	p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
-	index = 0;
-	for (;;) {
-		u64 l = min_t(u64, len, mapped_size);
-
-		crypto_shash_update(shash, p, l);
-		kunmap_atomic(mapped_buffer);
-		len -= l;
-		if (len == 0)
-			break;
-		index++;
-		BUG_ON(index >= sblock->page_count);
-		BUG_ON(!sblock->pagev[index]->page);
-		page = sblock->pagev[index]->page;
-		mapped_buffer = kmap_atomic(page);
-		mapped_size = PAGE_SIZE;
-		p = mapped_buffer;
-	}
+	shash->tfm = fs_info->csum_shash;
+	crypto_shash_init(shash);
+	crypto_shash_digest(shash, kaddr + BTRFS_CSUM_SIZE,
+			BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE, calculated_csum);
 
-	crypto_shash_final(shash, calculated_csum);
-	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
+	if (memcmp(calculated_csum, s->csum, sctx->csum_size))
 		++fail_cor;
 
 	if (fail_cor + fail_gen) {
@@ -1973,10 +1906,10 @@ static int scrub_checksum_super(struct scrub_block *sblock)
 		++sctx->stat.super_errors;
 		spin_unlock(&sctx->stat_lock);
 		if (fail_cor)
-			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
+			btrfs_dev_stat_inc_and_print(spage->dev,
 				BTRFS_DEV_STAT_CORRUPTION_ERRS);
 		else
-			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
+			btrfs_dev_stat_inc_and_print(spage->dev,
 				BTRFS_DEV_STAT_GENERATION_ERRS);
 	}
 
@@ -3758,7 +3691,7 @@ static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
 	struct btrfs_fs_info *fs_info = sctx->fs_info;
 
 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
-		return -EIO;
+		return -EROFS;
 
 	/* Seed devices of a new filesystem has their own generation. */
 	if (scrub_dev->fs_devices != fs_info->fs_devices)