This patch makes the chunk allocator keep a good ratio of metadata vs data block
groups. By default for every 8 data block groups, we'll allocate 1 metadata
chunk, or about 12% of the disk will be allocated for metadata. This can be
changed by specifying the metadata_ratio mount option. This is simply the
number of data block groups that have to be allocated to force a metadata chunk
allocation.
Signed-off-by: Josef Bacik <jba...@redhat.com>
---
fs/btrfs/ctree.h | 3 +++
fs/btrfs/disk-io.c | 1 +
fs/btrfs/extent-tree.c | 23 ++++++++++++++++++++++-
fs/btrfs/super.c | 12 +++++++++++-
4 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 86398a2..eff2ba5 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -888,6 +888,9 @@ struct btrfs_fs_info {
u64 metadata_alloc_profile;
u64 system_alloc_profile;
+ unsigned data_chunk_allocations;
+ unsigned metadata_ratio;
+
void *bdev_holder;
};
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d2e24c9..ddfd8af 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1601,6 +1601,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
fs_info->btree_inode = new_inode(sb);
fs_info->btree_inode->i_ino = 1;
fs_info->btree_inode->i_nlink = 1;
+ fs_info->metadata_ratio = 8;
fs_info->thread_pool_size = min_t(unsigned long,
num_online_cpus() + 2, 8);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index faa0c1d..f31da45 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1964,15 +1964,36 @@ void btrfs_delalloc_free_space(struct btrfs_root *root,
struct inode *inode,
spin_unlock(&info->lock);
}
+static void force_metadata_allocation(struct btrfs_fs_info *info)
+{
+ struct list_head *head = &info->space_info;
+ struct btrfs_space_info *found;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(found, head, list) {
+ if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
+ found->force_alloc = 1;
+ }
+ rcu_read_unlock();
+}
+
static int do_chunk_alloc(struct btrfs_trans_handle *trans,
struct btrfs_root *extent_root, u64 alloc_bytes,
u64 flags, int force)
{
struct btrfs_space_info *space_info;
+ struct btrfs_fs_info *fs_info = extent_root->fs_info;
u64 thresh;
int ret = 0;
- mutex_lock(&extent_root->fs_info->chunk_mutex);
+ mutex_lock(&fs_info->chunk_mutex);
+
+ if (flags & BTRFS_BLOCK_GROUP_DATA) {
+ fs_info->data_chunk_allocations++;
+ if (!(fs_info->data_chunk_allocations %
+ fs_info->metadata_ratio))
+ force_metadata_allocation(fs_info);
+ }
flags = btrfs_reduce_alloc_profile(extent_root, flags);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 19a4daf..92e3df0 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -66,7 +66,7 @@ static void btrfs_put_super(struct super_block *sb)
enum {
Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
- Opt_ssd, Opt_thread_pool, Opt_noacl, Opt_compress, Opt_err,
+ Opt_ssd, Opt_thread_pool, Opt_noacl, Opt_compress, Opt_ratio, Opt_err,
};
static match_table_t tokens = {
@@ -83,6 +83,7 @@ static match_table_t tokens = {
{Opt_compress, "compress"},
{Opt_ssd, "ssd"},
{Opt_noacl, "noacl"},
+ {Opt_ratio, "metadata_ratio=%d"},
{Opt_err, NULL},
};
@@ -222,6 +223,15 @@ int btrfs_parse_options(struct btrfs_root *root, char
*options)
case Opt_noacl:
root->fs_info->sb->s_flags &= ~MS_POSIXACL;
break;
+ case Opt_ratio:
+ intarg = 0;
+ match_int(&args[0], &intarg);
+ if (intarg) {
+ info->metadata_ratio = intarg;
+ printk(KERN_INFO "btrfs: metadata ratio %d\n",
+ info->metadata_ratio);
+ }
+ break;
default:
break;
}
--
1.5.4.3
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