The block group removal patch adds an alternate path to forget extents
other than btrfs_finish_extent_commit. As a result, any extents that would
be freed when the block group is removed aren't discarded. In my
test run, with a large copy of mixed sized files followed by removal, it
left nearly 2/3 of extents undiscarded.
As part of the extent removal review, I also added the discard call to
btrfs_destroy_pinned_extent.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
fs/btrfs/disk-io.c | 7 +++++++
fs/btrfs/extent-tree.c | 9 +++++++++
2 files changed, 16 insertions(+)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 639f266..f7dfcf8 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4167,6 +4167,13 @@ again:
if (ret)
break;
+ if (btrfs_test_opt(root, DISCARD)) {
+ ret = btrfs_discard_extent(root, start,
+ end + 1 - start, NULL);
+ if (ret)
+ break;
+ }
+
clear_extent_dirty(unpin, start, end, GFP_NOFS);
btrfs_error_unpin_extent_range(root, start, end);
cond_resched();
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 0bf45b8..6a7ff46 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9630,6 +9630,15 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
* a BUG_ON() at btrfs_unpin_extent_range().
*/
mutex_lock(&fs_info->unused_bg_unpin_mutex);
+ if (btrfs_test_opt(root, DISCARD)) {
+ ret = btrfs_discard_extent(root, start, end + 1 - start,
+ NULL);
+ if (ret) {
+ mutex_unlock(&fs_info->unused_bg_unpin_mutex);
+ btrfs_set_block_group_rw(root, block_group);
+ goto end_trans;
+ }
+ }
ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
EXTENT_DIRTY, GFP_NOFS);
if (ret) {
--
1.8.5.6
--
Jeff Mahoney
SUSE Labs
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