Btrfs: save balance parameters to disk
Introduce a new btree objectid for storing balance item. The reason is
to be able to resume restriper after a crash with the same parameters.
Balance item has a very high objectid and goes into tree of tree roots.
The key for the new item is as follows:
[ BTRFS_BALANCE_OBJECTID ; BTRFS_BALANCE_ITEM_KEY ; 0 ]
Older kernels simply ignore it so it's safe to mount with an older
kernel and then go back to the newer one.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1e7aea6..9997a59 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -86,6 +86,9 @@
/* holds checksums of all the data extents */
#define BTRFS_CSUM_TREE_OBJECTID 7ULL
+/* for storing balance parameters in the root tree */
+#define BTRFS_BALANCE_OBJECTID -4ULL
+
/* orhpan objectid for tracking unlinked/truncated files */
#define BTRFS_ORPHAN_OBJECTID -5ULL
@@ -692,6 +695,54 @@
__le16 name_len;
} __attribute__ ((__packed__));
+struct btrfs_disk_balance_args {
+ /*
+ * profiles to operate on, single is denoted by
+ * BTRFS_AVAIL_ALLOC_BIT_SINGLE
+ */
+ __le64 profiles;
+
+ /* usage filter */
+ __le64 usage;
+
+ /* devid filter */
+ __le64 devid;
+
+ /* devid subset filter [pstart..pend) */
+ __le64 pstart;
+ __le64 pend;
+
+ /* btrfs virtual address space subset filter [vstart..vend) */
+ __le64 vstart;
+ __le64 vend;
+
+ /*
+ * profile to convert to, single is denoted by
+ * BTRFS_AVAIL_ALLOC_BIT_SINGLE
+ */
+ __le64 target;
+
+ /* BTRFS_BALANCE_ARGS_* */
+ __le64 flags;
+
+ __le64 unused[8];
+} __attribute__ ((__packed__));
+
+/*
+ * store balance parameters to disk so that balance can be properly
+ * resumed after crash or unmount
+ */
+struct btrfs_balance_item {
+ /* BTRFS_BALANCE_* */
+ __le64 flags;
+
+ struct btrfs_disk_balance_args data;
+ struct btrfs_disk_balance_args meta;
+ struct btrfs_disk_balance_args sys;
+
+ __le64 unused[4];
+} __attribute__ ((__packed__));
+
#define BTRFS_FILE_EXTENT_INLINE 0
#define BTRFS_FILE_EXTENT_REG 1
#define BTRFS_FILE_EXTENT_PREALLOC 2
@@ -1409,6 +1460,8 @@
#define BTRFS_DEV_ITEM_KEY 216
#define BTRFS_CHUNK_ITEM_KEY 228
+#define BTRFS_BALANCE_ITEM_KEY 248
+
/*
* string items are for debugging. They just store a short string of
* data in the FS
@@ -2103,8 +2156,86 @@
BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,
num_devices, 64);
-/* struct btrfs_super_block */
+/* struct btrfs_balance_item */
+BTRFS_SETGET_FUNCS(balance_flags, struct btrfs_balance_item, flags, 64);
+static inline void btrfs_balance_data(struct extent_buffer *eb,
+ struct btrfs_balance_item *bi,
+ struct btrfs_disk_balance_args *ba)
+{
+ read_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
+}
+
+static inline void btrfs_set_balance_data(struct extent_buffer *eb,
+ struct btrfs_balance_item *bi,
+ struct btrfs_disk_balance_args *ba)
+{
+ write_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
+}
+
+static inline void btrfs_balance_meta(struct extent_buffer *eb,
+ struct btrfs_balance_item *bi,
+ struct btrfs_disk_balance_args *ba)
+{
+ read_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
+}
+
+static inline void btrfs_set_balance_meta(struct extent_buffer *eb,
+ struct btrfs_balance_item *bi,
+ struct btrfs_disk_balance_args *ba)
+{
+ write_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
+}
+
+static inline void btrfs_balance_sys(struct extent_buffer *eb,
+ struct btrfs_balance_item *bi,
+ struct btrfs_disk_balance_args *ba)
+{
+ read_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
+}
+
+static inline void btrfs_set_balance_sys(struct extent_buffer *eb,
+ struct btrfs_balance_item *bi,
+ struct btrfs_disk_balance_args *ba)
+{
+ write_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
+}
+
+static inline void
+btrfs_disk_balance_args_to_cpu(struct btrfs_balance_args *cpu,
+ struct btrfs_disk_balance_args *disk)
+{
+ memset(cpu, 0, sizeof(*cpu));
+
+ cpu->profiles = le64_to_cpu(disk->profiles);
+ cpu->usage = le64_to_cpu(disk->usage);
+ cpu->devid = le64_to_cpu(disk->devid);
+ cpu->pstart = le64_to_cpu(disk->pstart);
+ cpu->pend = le64_to_cpu(disk->pend);
+ cpu->vstart = le64_to_cpu(disk->vstart);
+ cpu->vend = le64_to_cpu(disk->vend);
+ cpu->target = le64_to_cpu(disk->target);
+ cpu->flags = le64_to_cpu(disk->flags);
+}
+
+static inline void
+btrfs_cpu_balance_args_to_disk(struct btrfs_disk_balance_args *disk,
+ struct btrfs_balance_args *cpu)
+{
+ memset(disk, 0, sizeof(*disk));
+
+ disk->profiles = cpu_to_le64(cpu->profiles);
+ disk->usage = cpu_to_le64(cpu->usage);
+ disk->devid = cpu_to_le64(cpu->devid);
+ disk->pstart = cpu_to_le64(cpu->pstart);
+ disk->pend = cpu_to_le64(cpu->pend);
+ disk->vstart = cpu_to_le64(cpu->vstart);
+ disk->vend = cpu_to_le64(cpu->vend);
+ disk->target = cpu_to_le64(cpu->target);
+ disk->flags = cpu_to_le64(cpu->flags);
+}
+
+/* struct btrfs_super_block */
BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);
BTRFS_SETGET_STACK_FUNCS(super_flags, struct btrfs_super_block, flags, 64);
BTRFS_SETGET_STACK_FUNCS(super_generation, struct btrfs_super_block,