From 279eebf766a3db072a854f3a7a830acb94be40b2 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Sat, 26 Mar 2011 08:32:30 +1100
Subject: [PATCH] Add lafs_find_free

to find some free segments.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 include/lafs/lafs.h    |  1 +
 lib/lafs_find_free.c   | 44 ++++++++++++++++++++++++++++++++++++++++++
 lib/lafs_new_segment.c |  8 +++++---
 tools/mkfs.lafs.c      |  1 -
 4 files changed, 50 insertions(+), 4 deletions(-)
 create mode 100644 lib/lafs_find_free.c

diff --git a/include/lafs/lafs.h b/include/lafs/lafs.h
index 792c804..f236911 100644
--- a/include/lafs/lafs.h
+++ b/include/lafs/lafs.h
@@ -32,6 +32,7 @@ struct lafs_ino *lafs_get_inode(struct lafs_ino *fsys, int inum);
 int lafs_imap_set(struct lafs_ino *, int inum);
 
 int lafs_add_free_seg(struct lafs*, int dev, loff_t seg);
+void lafs_find_free(struct lafs *fs);
 
 void lafs_inode_init(struct lafs *, char *, int type);
 struct lafs_ino *lafs_import_inode_buf(struct lafs *fs,
diff --git a/lib/lafs_find_free.c b/lib/lafs_find_free.c
new file mode 100644
index 0000000..145f3bf
--- /dev/null
+++ b/lib/lafs_find_free.c
@@ -0,0 +1,44 @@
+
+#include <lafs/lafs.h>
+#include "internal.h"
+
+/* lafs_find_free
+ * Find free blocks and add them to the list.
+ * Only run if free list is empty, to avoid any chance
+ * of duplicate entries.
+ * We add anything which has a youth of 0 in the
+ * segusage files, but not any currently open segment
+ */
+
+void lafs_find_free(struct lafs *fs)
+{
+	struct lafs_device *dev;
+	int mask = (1<<(fs->blockbits - 1)) - 1;
+
+	for (dev = fs->devs; dev; dev = dev->next) {
+		struct lafs_ino *ino = dev->segsum;
+		struct lafs_dblk *db = NULL;
+		loff_t seg;
+
+		for (seg = 0; seg < dev->segment_count; seg++) {
+			u32 bnum = seg >> (fs->blockbits-1);
+			if (db == NULL || db->b.fileaddr != bnum) {
+				db = lafs_dblk(ino, bnum);
+				if (!db || lafs_load_dblk(db))
+					break;
+				if (((u16*)db->b.data)[seg&mask] == 0) {
+					/* possible contender */
+					int s;
+					for (s = 0; s < WC_NUM;s++)
+						if (fs->wc[s].seg.dev == dev->devnum &&
+						    fs->wc[s].seg.num == seg)
+							break;
+					if (s == WC_NUM)
+						if (lafs_add_free_seg(fs, dev->devnum,
+								      seg) == 0)
+							return;
+				}
+			}
+		}
+	}
+}
diff --git a/lib/lafs_new_segment.c b/lib/lafs_new_segment.c
index 38c84d8..4efede2 100644
--- a/lib/lafs_new_segment.c
+++ b/lib/lafs_new_segment.c
@@ -35,10 +35,12 @@ int lafs_new_segment(struct lafs *fs, int cnum)
 	loff_t seg;
 	struct lafs_cluster *wc = &fs->wc[cnum];
 
-	if (fs->free_head == fs->free_tail)
+	if (fs->free_head == fs->free_tail) {
 		/* list is empty */
-		return 0;
-
+		lafs_find_free(fs);
+		if (fs->free_head == fs->free_tail)
+			return 0;
+	}
 	dev = fs->freelist[fs->free_head].dev;
 	seg = fs->freelist[fs->free_head].seg;
 
diff --git a/tools/mkfs.lafs.c b/tools/mkfs.lafs.c
index 784658d..484920c 100644
--- a/tools/mkfs.lafs.c
+++ b/tools/mkfs.lafs.c
@@ -270,7 +270,6 @@ int main(int argc, char *argv[])
 	lafs_imap_set(imfile, 16);
 
 	lafs_cluster_init(lafs, 0, 0, 0, 1);
-	lafs_add_free_seg(lafs, dev->devnum, 0);
 	/* Write checkpoint and state blocks */
 	lafs_checkpoint(lafs);
 	/* Write state blocks a second time, so all 4 copies are written */
-- 
2.43.0