[PATCH] erofs-utils: mkfs: add support to issue directory data separately

[Gao Xiang]

Especially since compressed directory data could be in the packing
inode, it would be better to compress them together.

It improves the overall compressed directory access performance.

Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
 include/erofs/importer.h |  2 ++
 lib/inode.c              | 68 ++++++++++++++++++++++++++++++++++++----
 mkfs/main.c              |  6 ++--
 3 files changed, 68 insertions(+), 8 deletions(-)

diff --git a/include/erofs/importer.h b/include/erofs/importer.h
index e1734b995ae8..a9d9c569d157 100644
--- a/include/erofs/importer.h
+++ b/include/erofs/importer.h
@@ -44,6 +44,8 @@ struct erofs_importer_params {
 	char force_inodeversion;
 	bool ignore_mtime;
 	bool no_datainline;
+	/* Issue directory data (except inline data) separately from regular inodes */
+	bool grouped_dirdata;
 	bool hard_dereference;
 	bool ovlfs_strip;
 	bool dot_omitted;
diff --git a/lib/inode.c b/lib/inode.c
index d993c8fd7428..1d08e39317c0 100644
--- a/lib/inode.c
+++ b/lib/inode.c
@@ -1494,6 +1494,7 @@ enum erofs_mkfs_jobtype {	/* ordered job types */
 
 struct erofs_mkfs_jobitem {
 	enum erofs_mkfs_jobtype type;
+	unsigned int _usize;
 	union {
 		struct erofs_inode *inode;
 		struct erofs_mkfs_job_ndir_ctx ndir;
@@ -1529,6 +1530,11 @@ static int erofs_mkfs_jobfn(struct erofs_importer *im,
 		if (inode->datalayout == EROFS_INODE_FLAT_INLINE)
 			inode->idata_size = inode->i_size & (bsz - 1);
 
+		/*
+		 * Directory on-disk inodes should be close to other inodes
+		 * in the parent directory since parent directories should
+		 * generally be prioritized.
+		 */
 		ret = erofs_prepare_inode_buffer(im, inode);
 		if (ret)
 			return ret;
@@ -1657,6 +1663,48 @@ static void erofs_mkfs_flushjobs(struct erofs_sb_info *sbi)
 }
 #endif
 
+struct erofs_mkfs_pending_jobitem {
+	struct list_head list;
+	struct erofs_mkfs_jobitem item;
+};
+
+int erofs_mkfs_push_pending_job(struct list_head *pending,
+				enum erofs_mkfs_jobtype type,
+				void *elem, int size)
+{
+	struct erofs_mkfs_pending_jobitem *pji;
+
+	pji = malloc(sizeof(*pji));
+	if (!pji)
+		return -ENOMEM;
+
+	pji->item.type = type;
+	if (size)
+		memcpy(&pji->item.u, elem, size);
+	pji->item._usize = size;
+	list_add_tail(&pji->list, pending);
+	return 0;
+}
+
+int erofs_mkfs_flush_pending_jobs(struct erofs_importer *im,
+				  struct list_head *q)
+{
+	struct erofs_mkfs_pending_jobitem *pji, *n;
+	int err2, err;
+
+	err = 0;
+	list_for_each_entry_safe(pji, n, q, list) {
+		list_del(&pji->list);
+
+		err2 = erofs_mkfs_go(im, pji->item.type, &pji->item.u,
+				     pji->item._usize);
+		free(pji);
+		if (!err)
+			err = err2;
+	}
+	return err;
+}
+
 static int erofs_mkfs_import_localdir(struct erofs_importer *im, struct erofs_inode *dir,
 				      u64 *nr_subdirs, unsigned int *i_nlink)
 {
@@ -1943,6 +1991,8 @@ static int erofs_mkfs_dump_tree(struct erofs_importer *im, bool rebuild,
 	struct erofs_inode *root = im->root;
 	struct erofs_sb_info *sbi = root->sbi;
 	struct erofs_inode *dumpdir = erofs_igrab(root);
+	bool grouped_dirdata = im->params->grouped_dirdata;
+	LIST_HEAD(pending_dirs);
 	int err, err2;
 
 	erofs_mark_parent_inode(root, root);	/* rootdir mark */
@@ -2009,13 +2059,19 @@ static int erofs_mkfs_dump_tree(struct erofs_importer *im, bool rebuild,
 		}
 		*last = dumpdir;	/* fixup the last (or the only) one */
 		dumpdir = head;
-		err2 = erofs_mkfs_go(im, EROFS_MKFS_JOB_DIR_BH,
-				     &dir, sizeof(dir));
-		if (err || err2)
-			return err ? err : err2;
+		err2 = grouped_dirdata ?
+			erofs_mkfs_push_pending_job(&pending_dirs,
+				EROFS_MKFS_JOB_DIR_BH, &dir, sizeof(dir)) :
+			erofs_mkfs_go(im, EROFS_MKFS_JOB_DIR_BH,
+				      &dir, sizeof(dir));
+		if (err || err2) {
+			if (!err)
+				err = err2;
+			break;
+		}
 	} while (dumpdir);
-
-	return err;
+	err2 = erofs_mkfs_flush_pending_jobs(im, &pending_dirs);
+	return err ? err : err2;
 }
 
 struct erofs_mkfs_buildtree_ctx {
diff --git a/mkfs/main.c b/mkfs/main.c
index 76bf84348364..9719aec7952e 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -1410,10 +1410,12 @@ static int mkfs_parse_options_cfg(struct erofs_importer_params *params,
 			tarerofs_decoder = EROFS_IOS_DECODER_GZRAN;
 			break;
 		case 536:
-			if (!optarg || strcmp(optarg, "1"))
+			if (!optarg || strcmp(optarg, "1")) {
 				params->compress_dir = true;
-			else
+				params->grouped_dirdata = true;
+			} else {
 				params->compress_dir = false;
+			}
 			break;
 		case 537:
 			if (!optarg || strcmp(optarg, "1"))
-- 
2.43.5