From: NeilBrown <neilb@suse.de>
Date: Sun, 19 Sep 2010 04:05:41 +0000 (+1000)
Subject: Generalise segunused to seg_pop
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=b9ffc03ff998e4626a092f46d0052a162e949ad3;p=LaFS.git

Generalise segunused to seg_pop

And use seg_pop more broadly,
and re-arrange some code.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/segments.c b/segments.c
index 12a6453..8b3acb3 100644
--- a/segments.c
+++ b/segments.c
@@ -1055,6 +1055,61 @@ static void segdelete_all(struct segtracker *st, struct fs *fs)
 	}
 }
 
+static u16 seg_pop(struct segtracker *st, struct slist *which)
+{
+	struct segstat *ss;
+	u16 rv = which->first;
+	if (rv == 0xFFFF)
+		return rv;
+	ss = segfollow(st, rv);
+	which->first = ss->next;
+	which->cnt--;
+	if (ss->next == 0xFFFF)
+		which->last = 0xFFFF;
+	return rv;
+}
+
+static struct segstat *seg_add_new(struct segtracker *st, struct slist *which, int atend,
+				   int dev, u32 seg, int score, int usage,
+				   u16 *where[SEG_NUM_HEIGHTS])
+{
+	int ssn;
+	struct segstat *ss;
+
+	ssn = seg_pop(st, &st->unused);
+	ss = segfollow(st, ssn);
+	if (!ss)
+		return ss;
+
+	if (which) {
+		if (atend) {
+			int l = which->last;
+			ss->next = 0xFFFF;
+			if (l == 0xFFFF) {
+				which->first = ssn;
+				which->last = ssn;
+			} else {
+				which->last = ssn;
+				BUG_ON(segfollow(st, l)->next != 0xFFFF);
+				segfollow(st, l)->next = ssn;
+			}
+		} else {
+			ss->next = which->first;
+			which->first = ssn;
+			if (which->last == 0xFFFF)
+				which->last = ssn;
+		}
+		which->cnt++;
+	}
+	ss->dev = dev;
+	ss->segment = seg;
+	ss->score = score;
+	ss->usage = usage;
+	seginsert(st, ssn, where);
+	lafs_check_seg_cnt(st);
+	return ss;
+}
+
 void lafs_free_get(struct fs *fs, unsigned int *dev, u32 *seg,
 		   int nonlogged)
 {
@@ -1108,13 +1163,10 @@ again:
 		lafs_pin_dblock(ssum->youthblk, AccountSpace);
 		goto again;
 	}
-	/* HACK youth_next should always be at least 0x8000 so that
-	 * cleanable score differentiates well for new segments.
-	 * old code would sometimes set youth_next very low, so
-	 * over-ride that
-	 */
-	if (fs->youth_next < 0x8000)
-		fs->youth_next = 0x8000;
+	seg_pop(fs->segtrack, &fs->segtrack->free);
+
+	ss->score = SCORE_ACTIVE;
+	/* still in table, but unlinked */
 
 	if (ssum && test_bit(DelayYouth, &fs->fsstate)) {
 		ss_put(ssum, fs);
@@ -1122,7 +1174,16 @@ again:
 	}
 
 	if (ssum) {
-		u16 y = fs->youth_next;
+		u16 y;
+		/* HACK youth_next should always be at least 0x8000 so that
+		 * cleanable score differentiates well for new segments.
+		 * old code would sometimes set youth_next very low, so
+		 * over-ride that
+		 */
+
+		if (fs->youth_next < 0x8000)
+			fs->youth_next = 0x8000;
+		y = fs->youth_next;
 		if (fs->scan.do_decay &&
 		    (fs->scan.free_dev < ss->dev
 		     || (fs->scan.free_dev == ss->dev 
@@ -1135,17 +1196,11 @@ again:
 		youthp[(*seg) & ((1 << (fs->blocksize_bits
 					- 1)) - 1)]
 			= cpu_to_le16(y);
+		fs->youth_next++;
 		unmap_dblock(ssum->youthblk, youthp);
 		lafs_dirty_dblock(ssum->youthblk);
 	}
-	fs->youth_next++;
 
-	fs->segtrack->free.first = ss->next;
-	if (fs->segtrack->free.first == 0xFFFF)
-		fs->segtrack->free.last = 0xFFFF;
-	fs->segtrack->free.cnt--;
-	ss->score = SCORE_ACTIVE;
-	/* still in table, but unlinked */
 	spin_unlock(&fs->lock);
 
 	/* now need to reserve/dirty/reference the youth and
@@ -1198,60 +1253,6 @@ void lafs_seg_forget(struct fs *fs, int dev, u32 seg)
 	ss_put(ss, fs);
 }
 
-static u16 segunused(struct segtracker *st)
-{
-	struct segstat *ss;
-	u16 rv = st->unused.first;
-	if (rv == 0xFFFF)
-		return rv;
-	ss = segfollow(st, rv);
-	st->unused.first = ss->next;
-	st->unused.cnt--;
-	ss->next = 0xFFFF;
-	return rv;
-}
-
-static struct segstat *seg_add_new(struct segtracker *st, struct slist *which, int atend,
-				   int dev, u32 seg, int score, int usage,
-				   u16 *where[SEG_NUM_HEIGHTS])
-{
-	int ssn;
-	struct segstat *ss;
-
-	ssn = segunused(st);
-	ss = segfollow(st, ssn);
-	if (!ss)
-		return ss;
-
-	if (which) {
-		if (atend) {
-			int l = which->last;
-			ss->next = 0xFFFF;
-			if (l == 0xFFFF) {
-				which->first = ssn;
-				which->last = ssn;
-			} else {
-				which->last = ssn;
-				BUG_ON(segfollow(st, l)->next != 0xFFFF);
-				segfollow(st, l)->next = ssn;
-			}
-		} else {
-			ss->next = which->first;
-			which->first = ssn;
-			if (which->last == 0xFFFF)
-				which->last = ssn;
-		}
-		which->cnt++;
-	}
-	ss->dev = dev;
-	ss->segment = seg;
-	ss->score = score;
-	ss->usage = usage;
-	seginsert(st, ssn, where);
-	lafs_check_seg_cnt(st);
-	return ss;
-}
-
 int lafs_clean_count(struct fs *fs, int *any_clean)
 {
 	int rv;
@@ -1527,11 +1528,7 @@ retry:
 
 	lafs_check_seg_cnt(fs->segtrack);
 
-	ss = segfollow(st, st->cleanable.first);
-	st->cleanable.first = ss->next;
-	st->cleanable.cnt--;
-	if (ss->next == 0xffff)
-		st->cleanable.last = 0xffff;
+	ss = segfollow(st, seg_pop(st, &st->cleanable));
 
 	if (lafs_check_seg_cnt(fs->segtrack)) {
 		int sj;