btrfs: make btrfs_issue_discard return bytes discarded

Initially this will just be the length argument passed to it,
but the following patches will adjust that to reflect re-alignment
and skipped blocks.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 07204bf601ed..16655bb5f293 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1883,10 +1883,17 @@ static int remove_extent_backref(struct btrfs_trans_handle *trans,
         return ret;
 }
 
-static int btrfs_issue_discard(struct block_device *bdev,
-                                u64 start, u64 len)
+static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
+                               u64 *discarded_bytes)
 {
-        return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
+        int ret = 0;
+
+        *discarded_bytes = 0;
+        ret = blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
+        if (!ret)
+                *discarded_bytes = len;
+
+        return ret;
 }
 
 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
@@ -1907,14 +1914,16 @@ int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 
 
                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
+                        u64 bytes;
                         if (!stripe->dev->can_discard)
                                 continue;
 
                         ret = btrfs_issue_discard(stripe->dev->bdev,
                                                   stripe->physical,
-                                                  stripe->length);
+                                                  stripe->length,
+                                                  &bytes);
                         if (!ret)
-                                discarded_bytes += stripe->length;
+                                discarded_bytes += bytes;
                         else if (ret != -EOPNOTSUPP)
                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */