btrfs: zoned: redirty released extent buffers
Tree manipulating operations like merging nodes often release
once-allocated tree nodes. Such nodes are cleaned so that pages in the
node are not uselessly written out. On zoned volumes, however, such
optimization blocks the following IOs as the cancellation of the write
out of the freed blocks breaks the sequential write sequence expected by
the device.
Introduce a list of clean and unwritten extent buffers that have been
released in a transaction. Redirty the buffers so that
btree_write_cache_pages() can send proper bios to the devices.
Besides it clears the entire content of the extent buffer not to confuse
raw block scanners e.g. 'btrfs check'. By clearing the content,
csum_dirty_buffer() complains about bytenr mismatch, so avoid the
checking and checksum using newly introduced buffer flag
EXTENT_BUFFER_NO_CHECK.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 00c0680..acff6bb 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -21,6 +21,7 @@
#include "qgroup.h"
#include "block-group.h"
#include "space-info.h"
+#include "zoned.h"
#define BTRFS_ROOT_TRANS_TAG 0
@@ -380,6 +381,8 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
spin_lock_init(&cur_trans->dirty_bgs_lock);
INIT_LIST_HEAD(&cur_trans->deleted_bgs);
spin_lock_init(&cur_trans->dropped_roots_lock);
+ INIT_LIST_HEAD(&cur_trans->releasing_ebs);
+ spin_lock_init(&cur_trans->releasing_ebs_lock);
list_add_tail(&cur_trans->list, &fs_info->trans_list);
extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
IO_TREE_TRANS_DIRTY_PAGES, fs_info->btree_inode);
@@ -2350,6 +2353,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
goto scrub_continue;
}
+ /*
+ * At this point, we should have written all the tree blocks allocated
+ * in this transaction. So it's now safe to free the redirtyied extent
+ * buffers.
+ */
+ btrfs_free_redirty_list(cur_trans);
+
ret = write_all_supers(fs_info, 0);
/*
* the super is written, we can safely allow the tree-loggers