Btrfs: add BTRFS_AVAIL_ALLOC_BIT_SINGLE bit
Right now on-disk BTRFS_BLOCK_GROUP_* profile bits are used for
avail_{data,metadata,system}_alloc_bits fields, which gather info about
available allocation profiles in the FS. When chunk is created or read
from disk, its profile is OR'ed with the corresponding avail_alloc_bits
field. Since SINGLE is denoted by 0 in the on-disk format, currently
there is no way to tell when such chunks become avaialble. Restriper
needs that information, so add a separate bit for SINGLE profile.
This bit is going to be in-memory only, it should never be written out
to disk, so it's not a disk format change. However to avoid remappings
in future, reserve corresponding on-disk bit.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4370a56..3f8f11e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -758,6 +758,7 @@
#define BTRFS_BLOCK_GROUP_RAID1 (1ULL << 4)
#define BTRFS_BLOCK_GROUP_DUP (1ULL << 5)
#define BTRFS_BLOCK_GROUP_RAID10 (1ULL << 6)
+#define BTRFS_BLOCK_GROUP_RESERVED BTRFS_AVAIL_ALLOC_BIT_SINGLE
#define BTRFS_NR_RAID_TYPES 5
#define BTRFS_BLOCK_GROUP_TYPE_MASK (BTRFS_BLOCK_GROUP_DATA | \
@@ -768,6 +769,15 @@
BTRFS_BLOCK_GROUP_RAID1 | \
BTRFS_BLOCK_GROUP_DUP | \
BTRFS_BLOCK_GROUP_RAID10)
+/*
+ * We need a bit for restriper to be able to tell when chunks of type
+ * SINGLE are available. This "extended" profile format is used in
+ * fs_info->avail_*_alloc_bits (in-memory) and balance item fields
+ * (on-disk). The corresponding on-disk bit in chunk.type is reserved
+ * to avoid remappings between two formats in future.
+ */
+#define BTRFS_AVAIL_ALLOC_BIT_SINGLE (1ULL << 48)
+
struct btrfs_block_group_item {
__le64 used;
__le64 chunk_objectid;
@@ -1140,6 +1150,11 @@
spinlock_t ref_cache_lock;
u64 total_ref_cache_size;
+ /*
+ * these three are in extended format (availability of single
+ * chunks is denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE bit, other
+ * types are denoted by corresponding BTRFS_BLOCK_GROUP_* bits)
+ */
u64 avail_data_alloc_bits;
u64 avail_metadata_alloc_bits;
u64 avail_system_alloc_bits;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a8d8204..15a2294 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3014,16 +3014,24 @@
static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
- if (extra_flags) {
- if (flags & BTRFS_BLOCK_GROUP_DATA)
- fs_info->avail_data_alloc_bits |= extra_flags;
- if (flags & BTRFS_BLOCK_GROUP_METADATA)
- fs_info->avail_metadata_alloc_bits |= extra_flags;
- if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
- fs_info->avail_system_alloc_bits |= extra_flags;
- }
+
+ /* chunk -> extended profile */
+ if (extra_flags == 0)
+ extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+
+ if (flags & BTRFS_BLOCK_GROUP_DATA)
+ fs_info->avail_data_alloc_bits |= extra_flags;
+ if (flags & BTRFS_BLOCK_GROUP_METADATA)
+ fs_info->avail_metadata_alloc_bits |= extra_flags;
+ if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+ fs_info->avail_system_alloc_bits |= extra_flags;
}
+/*
+ * @flags: available profiles in extended format (see ctree.h)
+ *
+ * Returns reduced profile in chunk format.
+ */
u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
{
/*
@@ -3053,8 +3061,12 @@
if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
((flags & BTRFS_BLOCK_GROUP_RAID1) |
(flags & BTRFS_BLOCK_GROUP_RAID10) |
- (flags & BTRFS_BLOCK_GROUP_DUP)))
+ (flags & BTRFS_BLOCK_GROUP_DUP))) {
flags &= ~BTRFS_BLOCK_GROUP_RAID0;
+ }
+
+ /* extended -> chunk profile */
+ flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
return flags;
}