[PATCH 02/17] Btrfs: fix truncate_space_check

David Sterba
2016-05-05T09:44:00Z

From: Josef Bacik <jbacik@fb.com>

truncate_space_check is using btrfs_csum_bytes_to_leaves() but forgetting to
multiply by nodesize so we get an actual byte count. We need a tracepoint here
so that we have the matching reserve for the release that will come later. Also
add a comment to make clear what the intent of truncate_space_check is.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/inode.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d96f5cf38a2d..0a4a2c141caa 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4211,11 +4211,20 @@ static int truncate_space_check(struct btrfs_trans_handle *trans,
{
int ret;

+ /*
+ * This is only used to apply pressure to the enospc system, we don't
+ * intend to use this reservation at all.
+ */
bytes_deleted = btrfs_csum_bytes_to_leaves(root, bytes_deleted);
+ bytes_deleted *= root->nodesize;
ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv,
bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
- if (!ret)
+ if (!ret) {
+ trace_btrfs_space_reservation(root->fs_info, "transaction",
+ trans->transid,
+ bytes_deleted, 1);
trans->bytes_reserved += bytes_deleted;
+ }
return ret;

}
--
2.7.1