[2/2] btrfs: add balance filter for stripes

Commit Message

David Sterba Oct. 13, 2015, 9:07 a.m. UTC

From: Gabríel Arthúr Pétursson <[e-mail]>

Balance block groups which have the given number of stripes, defined by
a range min..max. This is useful to selectively rebalance only chunks
that do not span enough devices, applies to RAID0/10/5/6.

Signed-off-by: Gabríel Arthúr Pétursson <[e-mail]>
[ renamed bargs members, added to the UAPI, wrote the changelog ]
Signed-off-by: David Sterba <[e-mail]>
---
 fs/btrfs/ctree.h           |  9 ++++++++-
 fs/btrfs/volumes.c         | 19 +++++++++++++++++++
 fs/btrfs/volumes.h         |  1 +
 include/uapi/linux/btrfs.h | 10 +++++++++-
 4 files changed, 37 insertions(+), 2 deletions(-)

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7d2e1b6d0ac1..e2eefa222999 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -859,7 +859,14 @@  struct btrfs_disk_balance_args {
 		};
 	};
 
-	__le64 unused[7];
+	/*
+	 * Process chunks that cross stripes_min..stripes_max devices,
+	 * BTRFS_BALANCE_ARGS_STRIPES
+	 */
+	__le32 stripes_min;
+	__le32 stripes_max;
+
+	__le64 unused[6];
 } __attribute__ ((__packed__));
 
 /*
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 0693e974f1c0..51c0e5b219a3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3170,6 +3170,19 @@  static int chunk_vrange_filter(struct extent_buffer *leaf,
 	return 1;
 }
 
+static int chunk_stripes_filter(struct extent_buffer *leaf,
+			       struct btrfs_chunk *chunk,
+			       struct btrfs_balance_args *bargs)
+{
+	int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+
+	if (bargs->stripes_min <= num_stripes
+			&& num_stripes <= bargs->stripes_max)
+		return 0;
+
+	return 1;
+}
+
 static int chunk_soft_convert_filter(u64 chunk_type,
 				     struct btrfs_balance_args *bargs)
 {
@@ -3236,6 +3249,12 @@  static int should_balance_chunk(struct btrfs_root *root,
 		return 0;
 	}
 
+	/* stripes filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_STRIPES) &&
+	    chunk_stripes_filter(leaf, chunk, bargs)) {
+		return 0;
+	}
+
 	/* soft profile changing mode */
 	if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
 	    chunk_soft_convert_filter(chunk_type, bargs)) {
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 1c9d8edd7d57..a87d96d75d07 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -376,6 +376,7 @@  struct map_lookup {
 #define BTRFS_BALANCE_ARGS_VRANGE	(1ULL << 4)
 #define BTRFS_BALANCE_ARGS_LIMIT	(1ULL << 5)
 #define BTRFS_BALANCE_ARGS_LIMITS	(1ULL << 6)
+#define BTRFS_BALANCE_ARGS_STRIPES	(1ULL << 7)
 
 /*
  * Profile changing flags.  When SOFT is set we won't relocate chunk if
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 264ecea5ecfc..ab720200d0f7 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -229,7 +229,15 @@  struct btrfs_balance_args {
 			__u32 limit_max;
 		};
 	};
-	__u64 unused[7];
+
+	/*
+	 * Process chunks that cross stripes_min..stripes_max devices,
+	 * BTRFS_BALANCE_ARGS_STRIPES
+	 */
+	__le32 stripes_min;
+	__le32 stripes_max;
+
+	__u64 unused[6];
 } __attribute__ ((__packed__));
 
 /* report balance progress to userspace */