Btrfs: cache ordered extent when completing io

When finishing io we run btrfs_dec_test_ordered_pending, and then immediately
run btrfs_lookup_ordered_extent, but btrfs_dec_test_ordered_pending does that
already, so we're searching twice when we don't have to.  This patch lets us
pass a btrfs_ordered_extent in to btrfs_dec_test_ordered_pending so if we do
complete io on that ordered extent we can just use the one we found then instead
of having to do another btrfs_lookup_ordered_extent.  This made my fio job with
the other patch go from 24 mb/s to 29 mb/s.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 50ce884..1824dda 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1698,11 +1698,10 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
        int compressed = 0;
        int ret;
 
-       ret = btrfs_dec_test_ordered_pending(inode, start, end - start + 1);
+       ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
+                                            end - start + 1);
        if (!ret)
                return 0;
-
-       ordered_extent = btrfs_lookup_ordered_extent(inode, start);
        BUG_ON(!ordered_extent);
 
        if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index d56f732..a8ffecd 100644 (file)
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -232,11 +232,12 @@ int btrfs_add_ordered_sum(struct inode *inode,
  * to make sure this function only returns 1 once for a given ordered extent.
  */
 int btrfs_dec_test_ordered_pending(struct inode *inode,
+                                  struct btrfs_ordered_extent **cached,
                                   u64 file_offset, u64 io_size)
 {
        struct btrfs_ordered_inode_tree *tree;
        struct rb_node *node;
-       struct btrfs_ordered_extent *entry;
+       struct btrfs_ordered_extent *entry = NULL;
        int ret;
 
        tree = &BTRFS_I(inode)->ordered_tree;
@@ -264,6 +265,10 @@ int btrfs_dec_test_ordered_pending(struct inode *inode,
        else
                ret = 1;
 out:
+       if (!ret && cached && entry) {
+               *cached = entry;
+               atomic_inc(&entry->refs);
+       }
        spin_unlock(&tree->lock);
        return ret == 0;
 }

diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index bfbcebb..c82f76a 100644 (file)
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -137,7 +137,8 @@ int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry);
 int btrfs_remove_ordered_extent(struct inode *inode,
                                struct btrfs_ordered_extent *entry);
 int btrfs_dec_test_ordered_pending(struct inode *inode,
-                                      u64 file_offset, u64 io_size);
+                                  struct btrfs_ordered_extent **cached,
+                                  u64 file_offset, u64 io_size);
 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
                             u64 start, u64 len, u64 disk_len, int tyep);
 int btrfs_add_ordered_sum(struct inode *inode,