lsblk: split sysfs reading and scols table filling

This change allows read devices from sysfs only once and reuse device
properties if the device is references more than once in the tree
(RAIDs, etc.).

* every device is in the tree only once (tree->devices list)

* iterate_block_devices() reuse already read devices (for example if
  already read for any dependence)

* the smartscols table is build from the final tree

The patch temporary disables dependencies evaluation (in
process_blkdev() to keep the patch small and simple.

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 56 insertions, 22 deletions

diff --git a/misc-utils/lsblk.c b/misc-utils/lsblk.c
index 9b9abd777..748e3cc34 100644
--- a/misc-utils/lsblk.c
+++ b/misc-utils/lsblk.c
@@ -984,16 +984,34 @@ static void set_scols_data(struct lsblk_device *dev, int col, int id, struct lib
 		err(EXIT_FAILURE, _("failed to add output data"));
 }
 
-static void fill_table_line(struct lsblk_device *dev, struct libscols_line *scols_parent)
+static void device_to_scols(struct lsblk_device *dev, struct lsblk_device *parent, struct libscols_table *tab)
 {
 	size_t i;
+	struct lsblk_iter itr;
+	struct lsblk_device *child = NULL;
 
-	dev->scols_line = scols_table_new_line(lsblk->table, scols_parent);
+	dev->scols_line = scols_table_new_line(tab, parent ? parent->scols_line : NULL);
 	if (!dev->scols_line)
 		err(EXIT_FAILURE, _("failed to allocate output line"));
 
 	for (i = 0; i < ncolumns; i++)
 		set_scols_data(dev, i, get_column_id(i), dev->scols_line);
+
+	lsblk_reset_iter(&itr, LSBLK_ITER_FORWARD);
+
+	while (lsblk_device_next_child(dev, &itr, &child) == 0)
+		device_to_scols(child, dev, tab);
+}
+
+static void devtree_to_scols(struct lsblk_devtree *tr, struct libscols_table *tab)
+{
+	struct lsblk_iter itr;
+	struct lsblk_device *dev = NULL;
+
+	lsblk_reset_iter(&itr, LSBLK_ITER_FORWARD);
+
+	while (lsblk_devtree_next_root(tr, &itr, &dev) == 0)
+		device_to_scols(dev, NULL, tab);
 }
 
 static int set_device(struct lsblk_device *dev,
@@ -1135,7 +1153,6 @@ static int list_partitions(struct lsblk_device *wholedisk_dev, struct lsblk_devi
 				goto next;
 
 			wholedisk_dev->parent = &part_dev;
-			fill_table_line(&part_dev, parent_dev ? parent_dev->scols_line : NULL);
 			if (!lsblk->nodeps)
 				process_blkdev(wholedisk_dev, &part_dev, 0, NULL);
 		} else {
@@ -1147,9 +1164,6 @@ static int list_partitions(struct lsblk_device *wholedisk_dev, struct lsblk_devi
 			 */
 			int ps = set_device(&part_dev, wholedisk_dev, wholedisk_dev, d->d_name);
 
-			/* Print whole disk only once */
-			if (r)
-				fill_table_line(wholedisk_dev, parent_dev ? parent_dev->scols_line : NULL);
 			if (ps == 0 && !lsblk->nodeps)
 				process_blkdev(&part_dev, wholedisk_dev, 0, NULL);
 		}
@@ -1244,20 +1258,20 @@ static int list_deps(struct lsblk_device *dev)
 static int process_blkdev(struct lsblk_device *dev, struct lsblk_device *parent,
 			  int do_partitions, const char *part_name)
 {
+#ifdef SUCK
 	if (do_partitions && dev->npartitions)
 		list_partitions(dev, parent, part_name);		/* partitions + whole-disk */
-	else
-		fill_table_line(dev, parent ? parent->scols_line : NULL); /* whole-disk only */
 
 	return list_deps(dev);
+#endif
+	return 0;
 }
 
 /* Iterate devices in sysfs */
-static int iterate_block_devices(void)
+static int iterate_block_devices(struct lsblk_devtree *tr)
 {
 	DIR *dir;
 	struct dirent *d;
-	struct lsblk_device dev = { .parent = NULL };
 	struct path_cxt *pc = ul_new_path(_PATH_SYS_BLOCK);
 
 	if (!pc)
@@ -1273,22 +1287,35 @@ static int iterate_block_devices(void)
 	DBG(DEV, ul_debug("iterate on " _PATH_SYS_BLOCK));
 
 	while ((d = xreaddir(dir))) {
+		struct lsblk_device *dev;
 
 		DBG(DEV, ul_debug(" %s dentry", d->d_name));
 
-		if (set_device(&dev, NULL, NULL, d->d_name))
-			goto next;
-
-		if (is_maj_excluded(dev.maj) || !is_maj_included(dev.maj))
-			goto next;
+		dev = lsblk_devtree_get_device(tr, d->d_name);
+		if (!dev) {
+			dev = lsblk_new_device(tr);
+			if (!dev)
+				err(EXIT_FAILURE, _("failed to allocate device"));
+			if (set_device(dev, NULL, NULL, d->d_name) != 0) {
+				lsblk_unref_device(dev);
+				continue;
+			}
+			lsblk_devtree_add_device(tr, dev);
+			lsblk_unref_device(dev);
+		} else
+			DBG(DEV, ul_debug(" %s: already processed", d->d_name));
 
-		/* Skip devices in the middle of dependency tree. */
-		if ((lsblk->inverse ? dev.nholders : dev.nslaves) > 0)
-			goto next;
+		/* remove unwanted devices */
+		if (is_maj_excluded(dev->maj) || !is_maj_included(dev->maj)) {
+			DBG(DEV, ul_debug(" %s: ignore (by filter)", d->d_name));
+			lsblk_devtree_remove_device(tr, dev);
+			continue;
+		}
 
-		process_blkdev(&dev, NULL, 1, NULL);
-	next:
-		reset_device(&dev);
+		/* process dependencies for top level devices */
+		if ((lsblk->inverse ? dev->nholders : dev->nslaves) <= 0
+		    && process_blkdev(dev, NULL, 1, NULL) == 0)
+			lsblk_devtree_add_root(tr, dev);
 	}
 
 	closedir(dir);
@@ -1498,6 +1525,7 @@ static void check_sysdevblock(void)
 int main(int argc, char *argv[])
 {
 	struct lsblk _ls = { .sort_id = -1, .flags = LSBLK_TREE };
+	struct lsblk_devtree *tr;
 	int c, status = EXIT_FAILURE;
 	char *outarg = NULL;
 	size_t i;
@@ -1785,8 +1813,12 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	tr = lsblk_new_devtree();
+	if (!tr)
+		err(EXIT_FAILURE, _("failed to allocate device tree"));
+
 	if (optind == argc)
-		status = iterate_block_devices() == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+		status = iterate_block_devices(tr) == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 	else {
 		int cnt = 0, cnt_err = 0;
 
@@ -1801,6 +1833,8 @@ int main(int argc, char *argv[])
 					  EXIT_SUCCESS;		/* all success */
 	}
 
+	devtree_to_scols(tr, lsblk->table);
+
 	if (lsblk->sort_col)
 		scols_sort_table(lsblk->table, lsblk->sort_col);
 	if (lsblk->force_tree_order)