diff mbox

[2/3] btrfs: add balance filter for stripes

Message ID aa6771ad37b6cd5370bccebfe525bd654f0d8a30.1445360598.git.dsterba@suse.com (mailing list archive)
State Accepted
Headers show

Commit Message

David Sterba Oct. 20, 2015, 5:13 p.m. UTC 
From: Gabríel Arthúr Pétursson <gabriel@system.is>

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 <gabriel@system.is>
[ renamed bargs members, added to the UAPI, wrote the changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
---
 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(-)

Comments

Christian Rohmann Jan. 14, 2016, 4:02 p.m. UTC | #1 
On 10/20/2015 07:13 PM, David Sterba wrote:
> 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.

This sounds like an awesome improvement to re-balance a filesystem with
newly added devices which don't have any data chunks yet. So in theory
for RAID6 I would simple need to execute

 btrfs balance start -dstripes=0..$devicecount-1 /filesystem


to have btrfs balance those chunks which are not spread across all
devices yet?



Regards

Christian
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David Sterba Jan. 15, 2016, 5:40 p.m. UTC | #2 
On Thu, Jan 14, 2016 at 05:02:35PM +0100, Christian Rohmann wrote:
> 
> 
> On 10/20/2015 07:13 PM, David Sterba wrote:
> > 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.
> 
> This sounds like an awesome improvement to re-balance a filesystem with
> newly added devices which don't have any data chunks yet. So in theory
> for RAID6 I would simple need to execute
> 
>  btrfs balance start -dstripes=0..$devicecount-1 /filesystem
> 
> 
> to have btrfs balance those chunks which are not spread across all
> devices yet?

Exactly.
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diff mbox

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 852c738d6954..76055a8317e9 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_RANGE
+	 */
+	__le32 stripes_min;
+	__le32 stripes_max;
+
+	__le64 unused[6];
 } __attribute__ ((__packed__));
 
 /*
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b90a79c2bcf9..8d88a8737c79 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_range_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_RANGE) &&
+	    chunk_stripes_range_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 c34578ee49f9..1d823ad3b914 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_LIMIT_RANGE	(1ULL << 6)
+#define BTRFS_BALANCE_ARGS_STRIPES_RANGE (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 11f13108b78b..17a94704b183 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_RANGE
+	 */
+	__le32 stripes_min;
+	__le32 stripes_max;
+
+	__u64 unused[6];
 } __attribute__ ((__packed__));
 
 /* report balance progress to userspace */