Btrfs: Discard sector data in __free_extent()

Date: Tue, 12 Aug 2008 14:13:26 +0100
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fff219ed61d9a7be5d76cbb8cff7771341fa5c3b..e63b3b4bed7c7a76e73c8bea7c778adf29e4a88b 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -18,6 +18,7 @@
 #include <linux/sched.h>
 #include <linux/pagemap.h>
 #include <linux/writeback.h>
+#include <linux/blkdev.h>
 #include "hash.h"
 #include "crc32c.h"
 #include "ctree.h"
@@ -1716,6 +1717,10 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
        if (refs == 0) {
                u64 super_used;
                u64 root_used;
+#ifdef BIO_RW_DISCARD
+               u64 map_length = num_bytes;
+               struct btrfs_multi_bio *multi = NULL;
+#endif
 
                if (pin) {
                        ret = pin_down_bytes(root, bytenr, num_bytes, 0);
@@ -1743,6 +1748,26 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                ret = update_block_group(trans, root, bytenr, num_bytes, 0,
                                         mark_free);
                BUG_ON(ret);
+
+#ifdef BIO_RW_DISCARD
+               /* Tell the block device(s) that the sectors can be discarded */
+               ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
+                                     bytenr, &map_length, &multi, 0);
+               if (!ret) {
+                       struct btrfs_bio_stripe *stripe = multi->stripes;
+                       int i;
+
+                       if (map_length > num_bytes)
+                               map_length = num_bytes;
+
+                       for (i = 0; i < multi->num_stripes; i++, stripe++) {
+                               blkdev_issue_discard(stripe->dev->bdev,
+                                                    stripe->physical >> 9,
+                                                    map_length >> 9);
+                       }
+                       kfree(multi);
+               }
+#endif
        }
        btrfs_free_path(path);
        finish_current_insert(trans, extent_root);