btrfs: add balance filter for stripes

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>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 460cd69..8ccbf43 100644 (file)
--- 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 e2fdd2e..9f5d167 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3220,6 +3220,19 @@ 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)
 {
@@ -3286,6 +3299,12 @@ 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 628d4e1..a5bf224 100644 (file)
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -381,6 +381,7 @@ 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)
 
 #define BTRFS_BALANCE_ARGS_MASK                        \
        (BTRFS_BALANCE_ARGS_PROFILES |          \

diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 11f1310..17a9470 100644 (file)
--- 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 */