[PATCH 12/35] btrfs: add ALLOC_CHUNK_FORCE to the flushing code

Josef Bacik
2018-08-30T21:46:06Z

With my change to no longer take into account the global reserve for
metadata allocation chunks we have this side-effect for mixed block
group fs'es where we are no longer allocating enough chunks for the
data/metadata requirements. To deal with this add a ALLOC_CHUNK_FORCE
step to the flushing state machine. This will only get used if we've
already made a full loop through the flushing machinery and tried
committing the transaction. If we have then we can try and force a
chunk allocation since we likely need it to make progress. This
resolves the issues I was seeing with the mixed bg tests in xfstests
with my previous patch.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.h | 3 ++-
fs/btrfs/extent-tree.c | 7 ++++++-
include/trace/events/btrfs.h | 1 +
3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0a4e55703d48..791e287c2292 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2731,7 +2731,8 @@ enum btrfs_flush_state {
FLUSH_DELALLOC = 5,
FLUSH_DELALLOC_WAIT = 6,
ALLOC_CHUNK = 7,
- COMMIT_TRANS = 8,
+ ALLOC_CHUNK_FORCE = 8,
+ COMMIT_TRANS = 9,
};

int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 783341e3653e..22e1f9f55f4f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4907,6 +4907,7 @@ static void flush_space(struct btrfs_fs_info *fs_info,
btrfs_end_transaction(trans);
break;
case ALLOC_CHUNK:
+ case ALLOC_CHUNK_FORCE:
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
@@ -4914,7 +4915,9 @@ static void flush_space(struct btrfs_fs_info *fs_info,
}
ret = do_chunk_alloc(trans,
btrfs_metadata_alloc_profile(fs_info),
- CHUNK_ALLOC_NO_FORCE);
+ (state == ALLOC_CHUNK) ?
+ CHUNK_ALLOC_NO_FORCE :
+ CHUNK_ALLOC_FORCE);
btrfs_end_transaction(trans);
if (ret > 0 || ret == -ENOSPC)
ret = 0;
@@ -5060,6 +5063,8 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
}
}
spin_unlock(&space_info->lock);
+ if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles)
+ flush_state++;
} while (flush_state <= COMMIT_TRANS);
}

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 7d205e50b09c..fdb23181b5b7 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1051,6 +1051,7 @@ TRACE_EVENT(btrfs_trigger_flush,
{ FLUSH_DELAYED_REFS_NR, "FLUSH_DELAYED_REFS_NR"}, \
{ FLUSH_DELAYED_REFS, "FLUSH_ELAYED_REFS"}, \
{ ALLOC_CHUNK, "ALLOC_CHUNK"}, \
+ { ALLOC_CHUNK_FORCE, "ALLOC_CHUNK_FORCE"}, \
{ COMMIT_TRANS, "COMMIT_TRANS"})

TRACE_EVENT(btrfs_flush_space,
--
2.14.3