From: Omar Sandoval <osan...@fb.com>
To start, let's tell btrfs-progs to read the free space root and how to
print the on-disk format of the free space tree. However, we're not
adding the FREE_SPACE_TREE read-only compat bit to the set of supported
bits because progs doesn't know how to keep the free space tree
consistent.
Signed-off-by: Omar Sandoval <osan...@fb.com>
---
btrfs-debug-tree.c | 4 ++++
ctree.h | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
disk-io.c | 16 +++++++++++++++-
print-tree.c | 25 +++++++++++++++++++++++++
4 files changed, 92 insertions(+), 2 deletions(-)
diff --git a/btrfs-debug-tree.c b/btrfs-debug-tree.c
index 7d8e876f1a2d..2aa5bd11d1b6 100644
--- a/btrfs-debug-tree.c
+++ b/btrfs-debug-tree.c
@@ -375,6 +375,10 @@ again:
if (!skip)
printf("uuid");
break;
+ case BTRFS_FREE_SPACE_TREE_OBJECTID:
+ if (!skip)
+ printf("free space");
+ break;
case BTRFS_MULTIPLE_OBJECTIDS:
if (!skip) {
printf("multiple");
diff --git a/ctree.h b/ctree.h
index c57f9cad5082..a37f3d1fcc48 100644
--- a/ctree.h
+++ b/ctree.h
@@ -76,6 +76,9 @@ struct btrfs_free_space_ctl;
/* for storing items that use the BTRFS_UUID_KEY* */
#define BTRFS_UUID_TREE_OBJECTID 9ULL
+/* tracks free space in block groups. */
+#define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL
+
/* for storing balance parameters in the root tree */
#define BTRFS_BALANCE_OBJECTID -4ULL
@@ -453,6 +456,8 @@ struct btrfs_super_block {
* Compat flags that we support. If any incompat flags are set other than the
* ones specified below then we will fail to mount
*/
+#define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE (1ULL << 0)
+
#define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF (1ULL << 0)
#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL (1ULL << 1)
#define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS (1ULL << 2)
@@ -476,9 +481,10 @@ struct btrfs_super_block {
#define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA (1ULL << 8)
#define BTRFS_FEATURE_INCOMPAT_NO_HOLES (1ULL << 9)
-
#define BTRFS_FEATURE_COMPAT_SUPP 0ULL
+
#define BTRFS_FEATURE_COMPAT_RO_SUPP 0ULL
+
#define BTRFS_FEATURE_INCOMPAT_SUPP \
(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF | \
BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL | \
@@ -898,6 +904,13 @@ struct btrfs_block_group_item {
__le64 flags;
} __attribute__ ((__packed__));
+struct btrfs_free_space_info {
+ __le32 extent_count;
+ __le32 flags;
+} __attribute__ ((__packed__));
+
+#define BTRFS_FREE_SPACE_USING_BITMAPS (1ULL << 0)
+
struct btrfs_qgroup_info_item {
__le64 generation;
__le64 referenced;
@@ -965,6 +978,7 @@ struct btrfs_fs_info {
struct btrfs_root *dev_root;
struct btrfs_root *csum_root;
struct btrfs_root *quota_root;
+ struct btrfs_root *free_space_root;
struct rb_root fs_root_tree;
@@ -1157,6 +1171,27 @@ struct btrfs_root {
*/
#define BTRFS_BLOCK_GROUP_ITEM_KEY 192
+/*
+ * Every block group is represented in the free space tree by a free space info
+ * item, which stores some accounting information. It is keyed on
+ * (block_group_start, FREE_SPACE_INFO, block_group_length).
+ */
+#define BTRFS_FREE_SPACE_INFO_KEY 198
+
+/*
+ * A free space extent tracks an extent of space that is free in a block group.
+ * It is keyed on (start, FREE_SPACE_EXTENT, length).
+ */
+#define BTRFS_FREE_SPACE_EXTENT_KEY 199
+
+/*
+ * When a block group becomes very fragmented, we convert it to use bitmaps
+ * instead of extents. A free space bitmap is keyed on
+ * (start, FREE_SPACE_BITMAP, length); the corresponding item is a bitmap with
+ * (length / sectorsize) bits.
+ */
+#define BTRFS_FREE_SPACE_BITMAP_KEY 200
+
#define BTRFS_DEV_EXTENT_KEY 204
#define BTRFS_DEV_ITEM_KEY 216
#define BTRFS_CHUNK_ITEM_KEY 228
@@ -1394,6 +1429,11 @@ BTRFS_SETGET_FUNCS(disk_block_group_flags,
BTRFS_SETGET_STACK_FUNCS(block_group_flags,
struct btrfs_block_group_item, flags, 64);
+/* struct btrfs_free_space_info */
+BTRFS_SETGET_FUNCS(free_space_extent_count, struct btrfs_free_space_info,
+ extent_count, 32);
+BTRFS_SETGET_FUNCS(free_space_flags, struct btrfs_free_space_info, flags, 32);
+
/* struct btrfs_inode_ref */
BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
BTRFS_SETGET_STACK_FUNCS(stack_inode_ref_name_len, struct btrfs_inode_ref,
name_len, 16);
@@ -2193,6 +2233,13 @@ static inline int btrfs_fs_incompat(struct btrfs_fs_info
*fs_info, u64 flag)
return !!(btrfs_super_incompat_flags(disk_super) & flag);
}
+static inline int btrfs_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag)
+{
+ struct btrfs_super_block *disk_super;
+ disk_super = fs_info->super_copy;
+ return !!(btrfs_super_compat_ro_flags(disk_super) & flag);
+}
+
/* helper function to cast into the data area of the leaf. */
#define btrfs_item_ptr(leaf, slot, type) \
((type *)(btrfs_leaf_data(leaf) + \
diff --git a/disk-io.c b/disk-io.c
index 8496aded31c4..ae9d6e1abb23 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -818,6 +818,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
free(fs_info->dev_root);
free(fs_info->csum_root);
free(fs_info->quota_root);
+ free(fs_info->free_space_root);
free(fs_info->super_copy);
free(fs_info->log_root_tree);
free(fs_info);
@@ -839,12 +840,13 @@ struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64
sb_bytenr)
fs_info->dev_root = calloc(1, sizeof(struct btrfs_root));
fs_info->csum_root = calloc(1, sizeof(struct btrfs_root));
fs_info->quota_root = calloc(1, sizeof(struct btrfs_root));
+ fs_info->free_space_root = calloc(1, sizeof(struct btrfs_root));
fs_info->super_copy = calloc(1, BTRFS_SUPER_INFO_SIZE);
if (!fs_info->tree_root || !fs_info->extent_root ||
!fs_info->chunk_root || !fs_info->dev_root ||
!fs_info->csum_root || !fs_info->quota_root ||
- !fs_info->super_copy)
+ !fs_info->free_space_root || !fs_info->super_copy)
goto free_all;
extent_io_tree_init(&fs_info->extent_cache);
@@ -1025,6 +1027,16 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info,
u64 root_tree_bytenr,
if (ret == 0)
fs_info->quota_enabled = 1;
+ if (btrfs_fs_compat_ro(fs_info,
BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE)) {
+ ret = find_and_setup_root(root, fs_info,
BTRFS_FREE_SPACE_TREE_OBJECTID,
+ fs_info->free_space_root);
+ if (ret) {
+ printk("Couldn't read free space tree\n");
+ return -EIO;
+ }
+ fs_info->free_space_root->track_dirty = 1;
+ }
+
ret = find_and_setup_log_root(root, fs_info, sb);
if (ret) {
printk("Couldn't setup log root tree\n");
@@ -1050,6 +1062,8 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info,
u64 root_tree_bytenr,
void btrfs_release_all_roots(struct btrfs_fs_info *fs_info)
{
+ if (fs_info->free_space_root)
+ free_extent_buffer(fs_info->free_space_root->node);
if (fs_info->quota_root)
free_extent_buffer(fs_info->quota_root->node);
if (fs_info->csum_root)
diff --git a/print-tree.c b/print-tree.c
index dc1d2764ae91..9dc058b58bde 100644
--- a/print-tree.c
+++ b/print-tree.c
@@ -610,6 +610,15 @@ static void print_key_type(u64 objectid, u8 type)
case BTRFS_BLOCK_GROUP_ITEM_KEY:
printf("BLOCK_GROUP_ITEM");
break;
+ case BTRFS_FREE_SPACE_INFO_KEY:
+ printf("FREE_SPACE_INFO");
+ break;
+ case BTRFS_FREE_SPACE_EXTENT_KEY:
+ printf("FREE_SPACE_EXTENT");
+ break;
+ case BTRFS_FREE_SPACE_BITMAP_KEY:
+ printf("FREE_SPACE_BITMAP");
+ break;
case BTRFS_CHUNK_ITEM_KEY:
printf("CHUNK_ITEM");
break;
@@ -728,6 +737,9 @@ static void print_objectid(u64 objectid, u8 type)
case BTRFS_UUID_TREE_OBJECTID:
printf("UUID_TREE");
break;
+ case BTRFS_FREE_SPACE_TREE_OBJECTID:
+ printf("FREE_SPACE_TREE");
+ break;
case BTRFS_MULTIPLE_OBJECTIDS:
printf("MULTIPLE");
break;
@@ -810,6 +822,7 @@ void btrfs_print_leaf(struct btrfs_root *root, struct
extent_buffer *l)
struct btrfs_dev_extent *dev_extent;
struct btrfs_disk_key disk_key;
struct btrfs_block_group_item bg_item;
+ struct btrfs_free_space_info *free_info;
struct btrfs_dir_log_item *dlog;
struct btrfs_qgroup_info_item *qg_info;
struct btrfs_qgroup_limit_item *qg_limit;
@@ -947,6 +960,18 @@ void btrfs_print_leaf(struct btrfs_root *root, struct
extent_buffer *l)
(unsigned long
long)btrfs_block_group_chunk_objectid(&bg_item),
flags_str);
break;
+ case BTRFS_FREE_SPACE_INFO_KEY:
+ free_info = btrfs_item_ptr(l, i, struct
btrfs_free_space_info);
+ printf("\t\tfree space info extent count %u flags %u\n",
+ (unsigned)btrfs_free_space_extent_count(l,
free_info),
+ (unsigned)btrfs_free_space_flags(l, free_info));
+ break;
+ case BTRFS_FREE_SPACE_EXTENT_KEY:
+ printf("\t\tfree space extent\n");
+ break;
+ case BTRFS_FREE_SPACE_BITMAP_KEY:
+ printf("\t\tfree space bitmap\n");
+ break;
case BTRFS_CHUNK_ITEM_KEY:
print_chunk(l, btrfs_item_ptr(l, i, struct
btrfs_chunk));
break;
--
2.6.0
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