Btrfs: adjust btrfs_discard_extent() return errors and trimmed bytes
Callers of btrfs_discard_extent() should check if we are mounted with -o discard,
as we want to make fitrim to work even the fs is not mounted with -o discard.
Also we should use REQ_DISCARD to map the free extent to get a full mapping,
last we only return errors if
1. the error is not a EOPNOTSUPP
2. no device supports discard
Signed-off-by: Li Dongyang <lidongyang@novell.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 0671f5b..e990d2d 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1738,39 +1738,45 @@
return ret;
}
-static void btrfs_issue_discard(struct block_device *bdev,
+static int btrfs_issue_discard(struct block_device *bdev,
u64 start, u64 len)
{
- blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
+ return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
}
static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
- u64 num_bytes)
+ u64 num_bytes, u64 *actual_bytes)
{
int ret;
- u64 map_length = num_bytes;
+ u64 discarded_bytes = 0;
struct btrfs_multi_bio *multi = NULL;
- if (!btrfs_test_opt(root, DISCARD))
- return 0;
/* 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);
+ ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
+ bytenr, &num_bytes, &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++) {
- btrfs_issue_discard(stripe->dev->bdev,
- stripe->physical,
- map_length);
+ ret = btrfs_issue_discard(stripe->dev->bdev,
+ stripe->physical,
+ stripe->length);
+ if (!ret)
+ discarded_bytes += stripe->length;
+ else if (ret != -EOPNOTSUPP)
+ break;
}
kfree(multi);
}
+ if (discarded_bytes && ret == -EOPNOTSUPP)
+ ret = 0;
+
+ if (actual_bytes)
+ *actual_bytes = discarded_bytes;
+
return ret;
}
@@ -4371,7 +4377,9 @@
if (ret)
break;
- ret = btrfs_discard_extent(root, start, end + 1 - start);
+ if (btrfs_test_opt(root, DISCARD))
+ ret = btrfs_discard_extent(root, start,
+ end + 1 - start, NULL);
clear_extent_dirty(unpin, start, end, GFP_NOFS);
unpin_extent_range(root, start, end);
@@ -5427,7 +5435,8 @@
return -ENOSPC;
}
- ret = btrfs_discard_extent(root, start, len);
+ if (btrfs_test_opt(root, DISCARD))
+ ret = btrfs_discard_extent(root, start, len, NULL);
btrfs_add_free_space(cache, start, len);
btrfs_update_reserved_bytes(cache, len, 0, 1);
@@ -8765,7 +8774,7 @@
}
int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
- u64 num_bytes)
+ u64 num_bytes, u64 *actual_bytes)
{
- return btrfs_discard_extent(root, bytenr, num_bytes);
+ return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
}
