btrfs: add new flushing states for the delayed refs rsv

A nice thing we gain with the delayed refs rsv is the ability to flush
the delayed refs on demand to deal with enospc pressure.  Add states to
flush delayed refs on demand, and this will allow us to remove a lot of
ad-hoc work around checking to see if we should commit the transaction
to run our delayed refs.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index ab9d9ed..d07a23f 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2765,10 +2765,12 @@ enum btrfs_reserve_flush_enum {
 enum btrfs_flush_state {
        FLUSH_DELAYED_ITEMS_NR  =       1,
        FLUSH_DELAYED_ITEMS     =       2,
-       FLUSH_DELALLOC          =       3,
-       FLUSH_DELALLOC_WAIT     =       4,
-       ALLOC_CHUNK             =       5,
-       COMMIT_TRANS            =       6,
+       FLUSH_DELAYED_REFS_NR   =       3,
+       FLUSH_DELAYED_REFS      =       4,
+       FLUSH_DELALLOC          =       5,
+       FLUSH_DELALLOC_WAIT     =       6,
+       ALLOC_CHUNK             =       7,
+       COMMIT_TRANS            =       8,
 };
 
 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 e2f6dbe..1b10c2f 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4938,6 +4938,20 @@ static void flush_space(struct btrfs_fs_info *fs_info,
                shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
                                state == FLUSH_DELALLOC_WAIT);
                break;
+       case FLUSH_DELAYED_REFS_NR:
+       case FLUSH_DELAYED_REFS:
+               trans = btrfs_join_transaction(root);
+               if (IS_ERR(trans)) {
+                       ret = PTR_ERR(trans);
+                       break;
+               }
+               if (state == FLUSH_DELAYED_REFS_NR)
+                       nr = calc_reclaim_items_nr(fs_info, num_bytes);
+               else
+                       nr = 0;
+               btrfs_run_delayed_refs(trans, nr);
+               btrfs_end_transaction(trans);
+               break;
        case ALLOC_CHUNK:
                trans = btrfs_join_transaction(root);
                if (IS_ERR(trans)) {

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 4b8400f..2887503 100644 (file)
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1048,6 +1048,8 @@ TRACE_EVENT(btrfs_trigger_flush,
                { FLUSH_DELAYED_ITEMS,          "FLUSH_DELAYED_ITEMS"},         \
                { FLUSH_DELALLOC,               "FLUSH_DELALLOC"},              \
                { FLUSH_DELALLOC_WAIT,          "FLUSH_DELALLOC_WAIT"},         \
+               { FLUSH_DELAYED_REFS_NR,        "FLUSH_DELAYED_REFS_NR"},       \
+               { FLUSH_DELAYED_REFS,           "FLUSH_ELAYED_REFS"},           \
                { ALLOC_CHUNK,                  "ALLOC_CHUNK"},                 \
                { COMMIT_TRANS,                 "COMMIT_TRANS"})