btrfs-progs: tune: add the ability to generate new data checksums

This patch would modify btrfs_csum_file_block() to handle csum type
other than the one used in the current fs.

The new data checksum would use a different objectid (-13) to
distinguish with the existing one (-10).
This needs to change tree-checker to skip the item size checks,
since new csum can be larger than the original csum.

After this stage, the resulted csum tree would look like this:

	item 0 key (CSUM_CHANGE EXTENT_CSUM 13631488) itemoff 8091 itemsize 8192
		range start 13631488 end 22020096 length 8388608
	item 1 key (EXTENT_CSUM EXTENT_CSUM 13631488) itemoff 7067 itemsize 1024
		range start 13631488 end 14680064 length 1048576

Note the itemsize is 8 times the original one, as the original csum is
CRC32, while target csum is SHA256, which is 8 times the size.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

check/mode-common.c

@@ -1209,18 +1209,19 @@ static int populate_csum(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *csum_root, char *buf, u64 start,
 			 u64 len)
 {
+	struct btrfs_fs_info *fs_info = trans->fs_info;
 	u64 offset = 0;
-	u64 sectorsize;
+	u64 sectorsize = fs_info->sectorsize;
 	int ret = 0;
 
 	while (offset < len) {
-		sectorsize = gfs_info->sectorsize;
-		ret = read_data_from_disk(gfs_info, buf, start + offset,
+		ret = read_data_from_disk(fs_info, buf, start + offset,
 					  &sectorsize, 0);
 		if (ret)
 			break;
-		ret = btrfs_csum_file_block(trans, start + len, start + offset,
-					    buf, sectorsize);
+		ret = btrfs_csum_file_block(trans, start + offset,
+					    BTRFS_EXTENT_CSUM_OBJECTID,
+					    fs_info->csum_type, buf);
 		if (ret)
 			break;
 		offset += sectorsize;

convert/main.c

@@ -182,7 +182,8 @@ static int csum_disk_extent(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root,
 			    u64 disk_bytenr, u64 num_bytes)
 {
-	u32 blocksize = root->fs_info->sectorsize;
+	struct btrfs_fs_info *fs_info = trans->fs_info;
+	u32 blocksize = fs_info->sectorsize;
 	u64 offset;
 	char *buffer;
 	int ret = 0;
@@ -193,7 +194,7 @@ static int csum_disk_extent(struct btrfs_trans_handle *trans,
 	for (offset = 0; offset < num_bytes; offset += blocksize) {
 		u64 read_len = blocksize;
 
-		ret = read_data_from_disk(root->fs_info, buffer,
+		ret = read_data_from_disk(fs_info, buffer,
 					  disk_bytenr + offset, &read_len, 0);
 		if (ret)
 			break;
@@ -203,10 +204,9 @@ static int csum_disk_extent(struct btrfs_trans_handle *trans,
 			ret = -EIO;
 			break;
 		}
-		ret = btrfs_csum_file_block(trans,
-					    disk_bytenr + num_bytes,
-					    disk_bytenr + offset,
-					    buffer, blocksize);
+		ret = btrfs_csum_file_block(trans, disk_bytenr + offset,
+					    BTRFS_EXTENT_CSUM_OBJECTID,
+					    fs_info->csum_type, buffer);
 		if (ret)
 			break;
 	}

kernel-shared/file-item.c

@@ -134,18 +134,18 @@ static struct btrfs_csum_item *
 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 		  struct btrfs_root *root,
 		  struct btrfs_path *path,
-		  u64 bytenr, int cow)
+		  u64 bytenr, u64 csum_objectid, u16 csum_type, int cow)
 {
 	int ret;
 	struct btrfs_key file_key;
 	struct btrfs_key found_key;
 	struct btrfs_csum_item *item;
 	struct extent_buffer *leaf;
 	u64 csum_offset = 0;
-	u16 csum_size = root->fs_info->csum_size;
+	u16 csum_size = btrfs_csum_type_size(csum_type);
 	int csums_in_item;
 
-	file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
+	file_key.objectid = csum_objectid;
 	file_key.offset = bytenr;
 	file_key.type = BTRFS_EXTENT_CSUM_KEY;
 	ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
@@ -159,7 +159,8 @@ btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 			goto fail;
 		path->slots[0]--;
 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
-		if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
+		if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
+		    found_key.objectid != csum_objectid)
 			goto fail;
 
 		csum_offset = (bytenr - found_key.offset) /
@@ -182,10 +183,10 @@ btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 	return ERR_PTR(ret);
 }
 
-int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
-			  u64 alloc_end, u64 bytenr, char *data, size_t len)
+int btrfs_csum_file_block(struct btrfs_trans_handle *trans, u64 logical,
+			  u64 csum_objectid, u32 csum_type, const char *data)
 {
-	struct btrfs_root *root = btrfs_csum_root(trans->fs_info, bytenr);
+	struct btrfs_root *root = btrfs_csum_root(trans->fs_info, logical);
 	int ret = 0;
 	struct btrfs_key file_key;
 	struct btrfs_key found_key;
@@ -199,18 +200,18 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 	u32 sectorsize = root->fs_info->sectorsize;
 	u32 nritems;
 	u32 ins_size;
-	u16 csum_size = root->fs_info->csum_size;
-	u16 csum_type = root->fs_info->csum_type;
+	u16 csum_size = btrfs_csum_type_size(csum_type);
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 
-	file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
-	file_key.offset = bytenr;
+	file_key.objectid = csum_objectid;
+	file_key.offset = logical;
 	file_key.type = BTRFS_EXTENT_CSUM_KEY;
 
-	item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
+	item = btrfs_lookup_csum(trans, root, path, logical, csum_objectid,
+				 csum_type, 1);
 	if (!IS_ERR(item)) {
 		leaf = path->nodes[0];
 		ret = 0;
@@ -241,7 +242,7 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 			slot = 0;
 		}
 		btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
-		if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
+		if (found_key.objectid != csum_objectid ||
 		    found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 			found_next = 1;
 			goto insert;
@@ -270,7 +271,7 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 	leaf = path->nodes[0];
 	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 	csum_offset = (file_key.offset - found_key.offset) / sectorsize;
-	if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
+	if (found_key.objectid != csum_objectid ||
 	    found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 	    csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
 		goto insert;
@@ -290,7 +291,7 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 	btrfs_release_path(path);
 	csum_offset = 0;
 	if (found_next) {
-		u64 tmp = min(alloc_end, next_offset);
+		u64 tmp = min(logical + sectorsize, next_offset);
 		tmp -= file_key.offset;
 		tmp /= sectorsize;
 		tmp = max((u64)1, tmp);
@@ -314,7 +315,8 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 	item = (struct btrfs_csum_item *)((unsigned char *)item +
 					  csum_offset * csum_size);
 found:
-	btrfs_csum_data(root->fs_info, csum_type, (u8 *)data, csum_result, len);
+	btrfs_csum_data(root->fs_info, csum_type, (u8 *)data, csum_result,
+			sectorsize);
 	write_extent_buffer(leaf, csum_result, (unsigned long)item,
 			    csum_size);
 	btrfs_mark_buffer_dirty(path->nodes[0]);

kernel-shared/file-item.h

@@ -80,8 +80,8 @@ int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root,
 			     u64 objectid, u64 pos, u64 offset,
 			     u64 disk_num_bytes, u64 num_bytes);
-int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
-			  u64 alloc_end, u64 bytenr, char *data, size_t len);
+int btrfs_csum_file_block(struct btrfs_trans_handle *trans, u64 logical,
+			  u64 csum_objectid, u32 csum_type, const char *data);
 int btrfs_insert_inline_extent(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root, u64 objectid,
 			       u64 offset, const char *buffer, size_t size);

kernel-shared/tree-checker.c

@@ -367,6 +367,11 @@ static int check_csum_item(struct extent_buffer *leaf, struct btrfs_key *key,
 	u32 sectorsize = fs_info->sectorsize;
 	const u32 csumsize = fs_info->csum_size;
 
+	/* For fs under csum change, we should not check the regular csum items. */
+	if (unlikely(btrfs_super_flags(fs_info->super_copy) &
+		     (BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM |
+		      BTRFS_SUPER_FLAG_CHANGING_META_CSUM)))
+		return 0;
 	if (unlikely(key->objectid != BTRFS_EXTENT_CSUM_OBJECTID)) {
 		generic_err(leaf, slot,
 		"invalid key objectid for csum item, have %llu expect %llu",

mkfs/rootdir.c

@@ -306,12 +306,13 @@ static int add_file_items(struct btrfs_trans_handle *trans,
 			  struct btrfs_inode_item *btrfs_inode, u64 objectid,
 			  struct stat *st, const char *path_name)
 {
+	struct btrfs_fs_info *fs_info = trans->fs_info;
 	int ret = -1;
 	ssize_t ret_read;
 	u64 bytes_read = 0;
 	struct btrfs_key key;
 	int blocks;
-	u32 sectorsize = root->fs_info->sectorsize;
+	u32 sectorsize = fs_info->sectorsize;
 	u64 first_block = 0;
 	u64 file_pos = 0;
 	u64 cur_bytes;
@@ -332,7 +333,7 @@ static int add_file_items(struct btrfs_trans_handle *trans,
 	if (st->st_size % sectorsize)
 		blocks += 1;
 
-	if (st->st_size <= BTRFS_MAX_INLINE_DATA_SIZE(root->fs_info) &&
+	if (st->st_size <= BTRFS_MAX_INLINE_DATA_SIZE(fs_info) &&
 	    st->st_size < sectorsize) {
 		char *buffer = malloc(st->st_size);
 
@@ -397,9 +398,9 @@ static int add_file_items(struct btrfs_trans_handle *trans,
 			goto end;
 		}
 
-		ret = btrfs_csum_file_block(trans,
-				first_block + bytes_read + sectorsize,
-				first_block + bytes_read, buf, sectorsize);
+		ret = btrfs_csum_file_block(trans, first_block + bytes_read,
+					    BTRFS_EXTENT_CSUM_OBJECTID,
+					    fs_info->csum_type, buf);
 		if (ret)
 			goto end;
 

tune/change-csum.c

@@ -21,6 +21,7 @@
 #include "kernel-shared/ctree.h"
 #include "kernel-shared/disk-io.h"
 #include "kernel-shared/volumes.h"
+#include "kernel-shared/file-item.h"
 #include "kernel-shared/extent_io.h"
 #include "kernel-shared/transaction.h"
 #include "common/messages.h"
@@ -180,7 +181,14 @@ static int generate_new_csum_range(struct btrfs_trans_handle *trans,
 			goto out;
 		}
 		/* Calculate new csum and insert it into the csum tree. */
-		ret = -EOPNOTSUPP;
+		ret = btrfs_csum_file_block(trans, cur,
+				BTRFS_CSUM_CHANGE_OBJECTID, new_csum_type, buf);
+		if (ret < 0) {
+			errno = -ret;
+			error("failed to insert new csum for data at logical %llu: %m",
+			      cur);
+			goto out;
+		}
 	}
 out:
 	free(buf);