Btrfs: add basic infrastructure for selective balancing

This allows to have a separate set of filters for each chunk type
(data,meta,sys).  The code however is generic and switch on chunk type
is only done once.

This commit also adds a type filter: it allows to balance for example
meta and system chunks w/o touching data ones.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d838d2c..29b3a94 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3116,6 +3116,9 @@ static long btrfs_ioctl_balance(struct btrfs_root *root, void __user *arg)
                memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
 
                bctl->flags = bargs->flags;
+       } else {
+               /* balance everything - no filters */
+               bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
        }
 
        ret = btrfs_balance(bctl, bargs);

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9fc06e6..91bbf6e 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2102,6 +2102,30 @@ static void unset_balance_control(struct btrfs_fs_info *fs_info)
        kfree(bctl);
 }
 
+static int should_balance_chunk(struct btrfs_root *root,
+                               struct extent_buffer *leaf,
+                               struct btrfs_chunk *chunk, u64 chunk_offset)
+{
+       struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
+       struct btrfs_balance_args *bargs = NULL;
+       u64 chunk_type = btrfs_chunk_type(leaf, chunk);
+
+       /* type filter */
+       if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
+             (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
+               return 0;
+       }
+
+       if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
+               bargs = &bctl->data;
+       else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
+               bargs = &bctl->sys;
+       else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
+               bargs = &bctl->meta;
+
+       return 1;
+}
+
 static u64 div_factor(u64 num, int factor)
 {
        if (factor == 10)
@@ -2119,10 +2143,13 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
        struct btrfs_device *device;
        u64 old_size;
        u64 size_to_free;
+       struct btrfs_chunk *chunk;
        struct btrfs_path *path;
        struct btrfs_key key;
        struct btrfs_key found_key;
        struct btrfs_trans_handle *trans;
+       struct extent_buffer *leaf;
+       int slot;
        int ret;
        int enospc_errors = 0;
 
@@ -2179,8 +2206,10 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
                        break;
                }
 
-               btrfs_item_key_to_cpu(path->nodes[0], &found_key,
-                                     path->slots[0]);
+               leaf = path->nodes[0];
+               slot = path->slots[0];
+               btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
                if (found_key.objectid != key.objectid)
                        break;
 
@@ -2188,7 +2217,14 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
                if (found_key.offset == 0)
                        break;
 
+               chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
+
+               ret = should_balance_chunk(chunk_root, leaf, chunk,
+                                          found_key.offset);
                btrfs_release_path(path);
+               if (!ret)
+                       goto loop;
+
                ret = btrfs_relocate_chunk(chunk_root,
                                           chunk_root->root_key.objectid,
                                           found_key.objectid,
@@ -2197,6 +2233,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
                        goto error;
                if (ret == -ENOSPC)
                        enospc_errors++;
+loop:
                key.offset = found_key.offset - 1;
        }
 
@@ -2227,6 +2264,7 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
                  struct btrfs_ioctl_balance_args *bargs)
 {
        struct btrfs_fs_info *fs_info = bctl->fs_info;
+       u64 allowed;
        int ret;
 
        if (btrfs_fs_closing(fs_info)) {
@@ -2234,6 +2272,23 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
                goto out;
        }
 
+       /*
+        * In case of mixed groups both data and meta should be picked,
+        * and identical options should be given for both of them.
+        */
+       allowed = btrfs_super_incompat_flags(fs_info->super_copy);
+       if ((allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
+           (bctl->flags & (BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA))) {
+               if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
+                   !(bctl->flags & BTRFS_BALANCE_METADATA) ||
+                   memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
+                       printk(KERN_ERR "btrfs: with mixed groups data and "
+                              "metadata balance options must be the same\n");
+                       ret = -EINVAL;
+                       goto out;
+               }
+       }
+
        set_balance_control(bctl);
 
        mutex_unlock(&fs_info->balance_mutex);

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 8825823..003e542 100644 (file)
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -186,6 +186,17 @@ struct map_lookup {
 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
                            (sizeof(struct btrfs_bio_stripe) * (n)))
 
+/*
+ * Restriper's general type filter
+ */
+#define BTRFS_BALANCE_DATA             (1ULL << 0)
+#define BTRFS_BALANCE_SYSTEM           (1ULL << 1)
+#define BTRFS_BALANCE_METADATA         (1ULL << 2)
+
+#define BTRFS_BALANCE_TYPE_MASK                (BTRFS_BALANCE_DATA |       \
+                                        BTRFS_BALANCE_SYSTEM |     \
+                                        BTRFS_BALANCE_METADATA)
+
 struct btrfs_balance_args;
 struct btrfs_balance_control {
        struct btrfs_fs_info *fs_info;