Introduce a new function, btrfs_read_one_data_csum(), to read just one
data csum for check usage.
Unlike original implement in cmds-check.c which checks csum by one
CSUM_EXTENT, this just read out one csum(4 bytes).
It is not fast but makes code easier to read.
And will be used in later fsck scrub codes.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
Makefile.in | 6 ++--
check/check.h | 21 +++++++++++++
check/csum.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 121 insertions(+), 2 deletions(-)
create mode 100644 check/check.h
create mode 100644 check/csum.c
diff --git a/Makefile.in b/Makefile.in
index b53cf2c..6e2407f 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -63,6 +63,7 @@ CFLAGS = @CFLAGS@ \
-fPIC \
-I$(TOPDIR) \
-I$(TOPDIR)/kernel-lib \
+ -I$(TOPDIR)/check \
$(EXTRAWARN_CFLAGS) \
$(DEBUG_CFLAGS_INTERNAL) \
$(EXTRA_CFLAGS)
@@ -93,7 +94,8 @@ objects = ctree.o disk-io.o kernel-lib/radix-tree.o
extent-tree.o print-tree.o \
extent-cache.o extent_io.o volumes.o utils.o repair.o \
qgroup.o raid56.o free-space-cache.o kernel-lib/list_sort.o props.o \
ulist.o qgroup-verify.o backref.o string-table.o task-utils.o \
- inode.o file.o find-root.o free-space-tree.o help.o
+ inode.o file.o find-root.o free-space-tree.o help.o \
+ check/csum.o
cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \
cmds-quota.o cmds-qgroup.o cmds-replace.o cmds-check.o \
@@ -463,7 +465,7 @@ clean-all: clean clean-doc clean-gen
clean: $(CLEANDIRS)
@echo "Cleaning"
$(Q)$(RM) -f -- $(progs) cscope.out *.o *.o.d \
- kernel-lib/*.o kernel-lib/*.o.d \
+ kernel-lib/*.o kernel-lib/*.o.d check/*.o check/*.o.d \
dir-test ioctl-test quick-test send-test library-test
library-test-static \
btrfs.static mkfs.btrfs.static \
$(check_defs) \
diff --git a/check/check.h b/check/check.h
new file mode 100644
index 0000000..61d1cac
--- /dev/null
+++ b/check/check.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2016 Fujitsu. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+/* check/csum.c */
+int btrfs_read_one_data_csum(struct btrfs_fs_info *fs_info, u64 bytenr,
+ void *csum_ret);
diff --git a/check/csum.c b/check/csum.c
new file mode 100644
index 0000000..53195ea
--- /dev/null
+++ b/check/csum.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2016 Fujitsu. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "ctree.h"
+#include "utils.h"
+/*
+ * TODO:
+ * 1) Add write support for csum
+ * So we can write new data extents and add csum into csum tree
+ * 2) Add csum range search function
+ * So we don't need to search csum tree in a per-sectorsize loop.
+ */
+
+int btrfs_read_one_data_csum(struct btrfs_fs_info *fs_info, u64 bytenr,
+ void *csum_ret)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_root *csum_root = fs_info->csum_root;
+ u32 item_offset;
+ u32 item_size;
+ u32 final_offset;
+ u32 sectorsize = fs_info->tree_root->sectorsize;
+ u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
+ int ret;
+
+ if (!csum_ret) {
+ error("wrong parameter for %s", __func__);
+ return -EINVAL;
+ }
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
+ key.type = BTRFS_EXTENT_CSUM_KEY;
+ key.offset = bytenr;
+
+ ret = btrfs_search_slot(NULL, csum_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (ret == 0) {
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ if (!IS_ALIGNED(key.offset, sectorsize)) {
+ error("csum item bytenr %llu is not aligned to %u",
+ key.offset, sectorsize);
+ ret = -EIO;
+ goto out;
+ }
+ u32 offset = btrfs_item_ptr_offset(path->nodes[0],
+ path->slots[0]);
+
+ read_extent_buffer(path->nodes[0], csum_ret, offset, csum_size);
+ goto out;
+ }
+ ret = btrfs_previous_item(csum_root, path, BTRFS_EXTENT_CSUM_OBJECTID,
+ BTRFS_EXTENT_CSUM_KEY);
+ if (ret)
+ goto out;
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ if (!IS_ALIGNED(key.offset, sectorsize)) {
+ error("csum item bytenr %llu is not aligned to %u",
+ key.offset, sectorsize);
+ ret = -EIO;
+ goto out;
+ }
+ item_offset = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
+ item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
+ if (key.offset + item_size / csum_size * sectorsize <= bytenr) {
+ ret = 1;
+ goto out;
+ }
+
+ final_offset = (bytenr - key.offset) / sectorsize * csum_size +
+ item_offset;
+ read_extent_buffer(path->nodes[0], csum_ret, final_offset, csum_size);
+ ret = 0;
+out:
+ btrfs_free_path(path);
+ return ret;
+};
--
2.10.0
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