This commit adds uuid-tree lookup methods that make use of the search
ioctl. The code is based on the kernel code.
Signed-off-by: Stefan Behrens <sbehr...@giantdisaster.de>
---
Makefile | 2 +-
ctree.h | 5 ++
uuid-tree.c | 196 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 202 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 7d4faba..f6f92c9 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ CFLAGS = -g -O1
objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
root-tree.o dir-item.o file-item.o inode-item.o inode-map.o \
extent-cache.o extent_io.o volumes.o utils.o repair.o \
- qgroup.o raid6.o free-space-cache.o
+ qgroup.o raid6.o free-space-cache.o uuid-tree.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 \
diff --git a/ctree.h b/ctree.h
index f25e2df..0ebb72a 100644
--- a/ctree.h
+++ b/ctree.h
@@ -2355,4 +2355,9 @@ struct btrfs_csum_item *btrfs_lookup_csum(struct
btrfs_trans_handle *trans,
int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
u64 isize);
+
+/* uuid-tree.c */
+int btrfs_lookup_uuid_subvol_item(int fd, const u8 *uuid, u64 *subvol_id);
+int btrfs_lookup_uuid_received_subvol_item(int fd, const u8 *uuid,
+ u64 *subvol_id);
#endif
diff --git a/uuid-tree.c b/uuid-tree.c
new file mode 100644
index 0000000..67c2584
--- /dev/null
+++ b/uuid-tree.c
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) STRATO AG 2013. 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 <stdio.h>
+#include <stdlib.h>
+#include <uuid/uuid.h>
+#include <sys/ioctl.h>
+#include "ctree.h"
+#include "transaction.h"
+#include "disk-io.h"
+#include "print-tree.h"
+
+
+/*
+ * One key is used to store a sequence of btrfs_uuid_item items.
+ * Each item in the sequence contains a type information and a sequence of
+ * ids (together with the information about the size of the sequence of ids).
+ * {[btrfs_uuid_item type0 {id0, id1, ..., idN}],
+ * ...,
+ * [btrfs_uuid_item typeZ {id0, id1, ..., idN}]}
+ *
+ * It is forbidden to put multiple items with the same type under the same key.
+ * Instead the sequence of ids is extended and used to store any additional
+ * ids for the same item type.
+ */
+
+static void btrfs_uuid_16xu8_to_2xu64(const u8 *uuid, u64 *first64,
+ u64 *second64)
+{
+ u64 val;
+ int i;
+ int j;
+
+ for (i = 0; i < 2; i++) {
+ val = 0;
+ for (j = 7; j >= 0; j--) {
+ /* in host byte order, resulting disk key is le */
+ val |= ((u64)*uuid) << (j * 8);
+ uuid++;
+ }
+ if (!i)
+ *first64 = val;
+ else
+ *second64 = val;
+ }
+}
+
+static struct btrfs_uuid_item *btrfs_match_uuid_item_type(
+ struct btrfs_uuid_item *ptr, u32 item_size, u64 type)
+{
+ do {
+ u64 sub_item_type;
+ u64 sub_item_len;
+
+ if (item_size < sizeof(*ptr)) {
+ fprintf(stderr,
+ "btrfs: uuid item too short (%llu < %d)!\n",
+ (unsigned long long)item_size,
+ (int)sizeof(*ptr));
+ return NULL;
+ }
+ item_size -= sizeof(*ptr);
+ sub_item_type = le64_to_cpu(ptr->type);
+ sub_item_len = le64_to_cpu(ptr->len);
+ if (sub_item_len * 8 > item_size) {
+ fprintf(stderr,
+ "btrfs: uuid item too short (%llu > %llu)!\n",
+ (unsigned long long)(sub_item_len * 8),
+ (unsigned long long)item_size);
+ return NULL;
+ }
+ if (sub_item_type == type)
+ return ptr;
+ item_size -= sub_item_len * 8;
+ ptr = 1 + (struct btrfs_uuid_item *)
+ (((char *)ptr) + (sub_item_len * 8));
+ } while (item_size);
+
+ return NULL;
+}
+
+static int btrfs_uuid_tree_lookup_prepare(int fd, const u8 *uuid, u64 type,
+ struct btrfs_ioctl_search_args
+ *search_arg,
+ struct btrfs_uuid_item **ptr)
+{
+ int ret;
+ u64 key_objectid = 0;
+ u64 key_offset;
+ struct btrfs_uuid_item *uuid_item;
+ struct btrfs_ioctl_search_header *search_header;
+ u32 item_size;
+
+ btrfs_uuid_16xu8_to_2xu64(uuid, &key_objectid, &key_offset);
+
+ memset(search_arg, 0, sizeof(*search_arg));
+ search_arg->key.tree_id = BTRFS_UUID_TREE_OBJECTID;
+ search_arg->key.min_objectid = key_objectid;
+ search_arg->key.max_objectid = key_objectid;
+ search_arg->key.min_type = BTRFS_UUID_KEY;
+ search_arg->key.max_type = BTRFS_UUID_KEY;
+ search_arg->key.min_offset = key_offset;
+ search_arg->key.max_offset = key_offset;
+ search_arg->key.max_transid = (u64)-1;
+ search_arg->key.nr_items = 1;
+ ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, search_arg);
+ if (ret) {
+ fprintf(stderr,
+ "ioctl(BTRFS_IOC_TREE_SEARCH, uuid, key %016llx,
UUID_KEY, %016llx) ret=%d, error: %s\n",
+ (unsigned long long)key_objectid,
+ (unsigned long long)key_offset, ret, strerror(errno));
+ ret = -ENOENT;
+ goto out;
+ }
+
+ if (search_arg->key.nr_items < 1) {
+ ret = -ENOENT;
+ goto out;
+ }
+ search_header = (struct btrfs_ioctl_search_header *)(search_arg->buf);
+ uuid_item = (struct btrfs_uuid_item *)(search_header + 1);
+ item_size = search_header->len;
+
+ *ptr = btrfs_match_uuid_item_type(uuid_item, item_size, type);
+ if (!*ptr) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ ret = 0;
+
+out:
+ return ret;
+}
+
+/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
+static int btrfs_uuid_tree_lookup_any(int fd, const u8 *uuid, u64 type,
+ u64 *subid)
+{
+ int ret;
+ struct btrfs_ioctl_search_args search_arg;
+ struct btrfs_uuid_item *ptr;
+ u64 sub_item_len;
+
+ ret = btrfs_uuid_tree_lookup_prepare(fd, uuid, type, &search_arg, &ptr);
+ if (ret < 0)
+ goto out;
+
+ sub_item_len = le64_to_cpu(ptr->len);
+ if (sub_item_len > 0) {
+ /* return first stored id */
+ memcpy(subid, ptr + 1, sizeof(*subid));
+ ret = 0;
+ } else {
+ ret = -ENOENT;
+ }
+
+out:
+ return ret;
+}
+
+int btrfs_lookup_uuid_subvol_item(int fd, const u8 *uuid, u64 *subvol_id)
+{
+ int ret;
+
+ ret = btrfs_uuid_tree_lookup_any(fd, uuid, BTRFS_UUID_ITEM_TYPE_SUBVOL,
+ subvol_id);
+ *subvol_id = le64_to_cpu(*subvol_id);
+ return ret;
+}
+
+int btrfs_lookup_uuid_received_subvol_item(int fd, const u8 *uuid,
+ u64 *subvol_id)
+{
+ int ret;
+
+ ret = btrfs_uuid_tree_lookup_any(fd, uuid,
+ BTRFS_UUID_ITEM_TYPE_RECEIVED_SUBVOL,
+ subvol_id);
+ *subvol_id = le64_to_cpu(*subvol_id);
+ return ret;
+}
--
1.8.2.1
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