btrfs: qgroups: remove bytenr field from struct btrfs_qgroup_extent_record

Now that we track qgroup extent records in a xarray we don't need to have
a "bytenr" field in  struct btrfs_qgroup_extent_record, since we can get
it from the index of the record in the xarray.

So remove the field and grab the bytenr from either the index key or any
other place where it's available (delayed refs). This reduces the size of
struct btrfs_qgroup_extent_record from 40 bytes down to 32 bytes, meaning
that we now can store 128 instances of this structure instead of 102 per
4K page.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 17 insertions, 14 deletions

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index a0e8deca87a7..da618e34acd4 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2001,27 +2001,28 @@ out:
  * Return <0 for insertion failure, caller can free @record safely.
  */
 int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
-				struct btrfs_delayed_ref_root *delayed_refs,
-				struct btrfs_qgroup_extent_record *record)
+				     struct btrfs_delayed_ref_root *delayed_refs,
+				     struct btrfs_qgroup_extent_record *record,
+				     u64 bytenr)
 {
 	struct btrfs_qgroup_extent_record *existing, *ret;
-	const unsigned long index = (record->bytenr >> fs_info->sectorsize_bits);
+	const unsigned long index = (bytenr >> fs_info->sectorsize_bits);
 
 	if (!btrfs_qgroup_full_accounting(fs_info))
 		return 1;
 
 #if BITS_PER_LONG == 32
-	if (record->bytenr >= MAX_LFS_FILESIZE) {
+	if (bytenr >= MAX_LFS_FILESIZE) {
 		btrfs_err_rl(fs_info,
 "qgroup record for extent at %llu is beyond 32bit page cache and xarray index limit",
-			     record->bytenr);
+			     bytenr);
 		btrfs_err_32bit_limit(fs_info);
 		return -EOVERFLOW;
 	}
 #endif
 
 	lockdep_assert_held(&delayed_refs->lock);
-	trace_btrfs_qgroup_trace_extent(fs_info, record);
+	trace_btrfs_qgroup_trace_extent(fs_info, record, bytenr);
 
 	xa_lock(&delayed_refs->dirty_extents);
 	existing = xa_load(&delayed_refs->dirty_extents, index);
@@ -2066,7 +2067,8 @@ int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
  * transaction committing, but not now as qgroup accounting will be wrong again.
  */
 int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
-				   struct btrfs_qgroup_extent_record *qrecord)
+				   struct btrfs_qgroup_extent_record *qrecord,
+				   u64 bytenr)
 {
 	struct btrfs_backref_walk_ctx ctx = { 0 };
 	int ret;
@@ -2097,7 +2099,7 @@ int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
 	if (trans->fs_info->qgroup_flags & BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING)
 		return 0;
 
-	ctx.bytenr = qrecord->bytenr;
+	ctx.bytenr = bytenr;
 	ctx.fs_info = trans->fs_info;
 
 	ret = btrfs_find_all_roots(&ctx, true);
@@ -2154,12 +2156,11 @@ int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
 	}
 
 	delayed_refs = &trans->transaction->delayed_refs;
-	record->bytenr = bytenr;
 	record->num_bytes = num_bytes;
 	record->old_roots = NULL;
 
 	spin_lock(&delayed_refs->lock);
-	ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record);
+	ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record, bytenr);
 	spin_unlock(&delayed_refs->lock);
 	if (ret) {
 		/* Clean up if insertion fails or item exists. */
@@ -2167,7 +2168,7 @@ int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
 		kfree(record);
 		return 0;
 	}
-	return btrfs_qgroup_trace_extent_post(trans, record);
+	return btrfs_qgroup_trace_extent_post(trans, record, bytenr);
 }
 
 /*
@@ -3043,14 +3044,16 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
 	delayed_refs = &trans->transaction->delayed_refs;
 	qgroup_to_skip = delayed_refs->qgroup_to_skip;
 	xa_for_each(&delayed_refs->dirty_extents, index, record) {
+		const u64 bytenr = (((u64)index) << fs_info->sectorsize_bits);
+
 		num_dirty_extents++;
-		trace_btrfs_qgroup_account_extents(fs_info, record);
+		trace_btrfs_qgroup_account_extents(fs_info, record, bytenr);
 
 		if (!ret && !(fs_info->qgroup_flags &
 			      BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING)) {
 			struct btrfs_backref_walk_ctx ctx = { 0 };
 
-			ctx.bytenr = record->bytenr;
+			ctx.bytenr = bytenr;
 			ctx.fs_info = fs_info;
 
 			/*
@@ -3092,7 +3095,7 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
 				ulist_del(record->old_roots, qgroup_to_skip,
 					  0);
 			}
-			ret = btrfs_qgroup_account_extent(trans, record->bytenr,
+			ret = btrfs_qgroup_account_extent(trans, bytenr,
 							  record->num_bytes,
 							  record->old_roots,
 							  new_roots);