From 78826b67500c4fd4269822854ed0ee51be0898d3 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Sat, 2 Oct 2010 21:56:29 +1000
Subject: [PATCH] roll forward clean up

More validation
improved mem allocation
general clean up

Signed-off-by: NeilBrown <neilb@suse.de>
---
 roll.c | 100 +++++++++++++++++++++++++++++++--------------------------
 1 file changed, 55 insertions(+), 45 deletions(-)

diff --git a/roll.c b/roll.c
index ba986cb..a4dea4b 100644
--- a/roll.c
+++ b/roll.c
@@ -23,7 +23,18 @@ roll_valid(struct fs *fs, struct cluster_head *ch, unsigned long long addr)
 		return 0;
 	if (le64_to_cpu(ch->this_addr) != addr)
 		return 0;
-	/* FIXME sanity check some values?? */
+	switch (le16_to_cpu(ch->verify_type)) {
+	case VerifyNull:
+	case VerifyNext:
+	case VerifyNext2:
+		break;
+	default:
+		return 0;
+	}
+	if (ch->pad0 != 0)
+		return 0;
+	if (le16_to_cpu(ch->Clength) > fs->max_segment)
+		return 0;
 	return 1;
 }
 
@@ -36,18 +47,14 @@ roll_valid(struct fs *fs, struct cluster_head *ch, unsigned long long addr)
 static int
 roll_locate(struct fs *fs, u64 start,
 	    u64 *next, u64 *lastp, u64 *seqp,
-	    int *maxp)
+	    int *maxp, struct page *p)
 {
-	struct page *p = alloc_page(GFP_KERNEL);
-
 	struct cluster_head *ch;
 	u64 this, prev, prev2, last;
 	u64 seq = 0;
 	int max = 0;
 	int prevtype, prev2type;
 
-	if (!p)
-		return -ENOMEM;
 	ch = (struct cluster_head *)page_address(p);
 
 	this = start; prev = start;
@@ -136,7 +143,7 @@ roll_locate(struct fs *fs, u64 start,
 		if (le16_to_cpu(ch->Hlength) > max)
 			max = le16_to_cpu(ch->Hlength);
 
-		if (prev2type == VerifyNext2 && start != this) {
+		if (prev2type == VerifyNext2) {
 			start = prev; last = prev2;
 		}
 		if (prevtype == VerifyNext) {
@@ -148,6 +155,10 @@ roll_locate(struct fs *fs, u64 start,
 		prev2 = prev; prev2type = prevtype;
 		prev = this ; prevtype = le16_to_cpu(ch->verify_type);
 		this = le64_to_cpu(ch->next_addr);
+		if (prevtype == VerifyNull) {
+			start = this;
+			last = prev;
+		}
 		seq++;
 	}
 
@@ -477,7 +488,6 @@ static int roll_forward(struct fs *fs)
 	u64 first, next = 0, last = 0, seq = 0;
 	int max = 0;
 	struct page *p, *pg;
-	char *buf;
 	int err;
 	int blocksize = fs->blocksize;
 	int dev;
@@ -490,15 +500,21 @@ static int roll_forward(struct fs *fs)
 	clear_bit(DelayYouth, &fs->fsstate);
 
 	first = fs->checkpointcluster;
-	err = roll_locate(fs, first, &next, &last, &seq, &max);
-	if (err)
-		return err;
-	if (max > PAGE_SIZE)
-		return -EFBIG;
-
 	p = alloc_page(GFP_KERNEL);
 	if (!p)
 		return -ENOMEM;
+
+	err = roll_locate(fs, first, &next, &last, &seq, &max, p);
+
+	max = ((max + blocksize - 1) / blocksize) * blocksize;
+
+	if (!err && max > PAGE_SIZE)
+		err = -EFBIG;
+	if (err) {
+		put_page(p);
+		return err;
+	}
+
 	pg = alloc_page(GFP_KERNEL);
 	if (!pg) {
 		put_page(p);
@@ -513,42 +529,36 @@ static int roll_forward(struct fs *fs)
 	lafs_cluster_init(fs, 1, 0, 0, 0);
 
 	virttoseg(fs, first, &dev, &seg, &offset);
-	max = ((max + blocksize - 1) / blocksize) * blocksize;
-	dprintk("Max = %d\n", max);
-	buf = kmalloc(max, GFP_KERNEL);
-	if (buf)
-		while (first != next) {
-			int dev2;
-			u32 seg2;
-
-			virttoseg(fs, first, &dev2, &seg2, &offset);
-			err = roll_one(fs, &first, p, pg, max);
-			if (err)
-				break;
 
-			if (fs->qphase == fs->phase &&
-			    fs->checkpointing) {
-				fs->checkpointing = 0;
-				clear_bit(DelayYouth, &fs->fsstate);
-				lafs_seg_apply_all(fs);
-			}
+	while (first != next) {
+		int dev2;
+		u32 seg2;
 
-			if (dev2 != dev || seg2 != seg) {
-				/* New segment - need to make sure youth is correct */
-				dev = dev2;
-				seg = seg2;
-				/* if fs->checkpointing, seg_apply_all will do the youth
-				 * update
-				 */
-				if (fs->checkpointing == 0)
-					lafs_update_youth(fs, dev, seg);
-			}
+		virttoseg(fs, first, &dev2, &seg2, &offset);
+		err = roll_one(fs, &first, p, pg, max);
+		if (err)
+			break;
+
+		if (fs->qphase == fs->phase &&
+		    fs->checkpointing) {
+			fs->checkpointing = 0;
+			clear_bit(DelayYouth, &fs->fsstate);
+			lafs_seg_apply_all(fs);
 		}
-	else
-		err = -ENOMEM;
+
+		if (dev2 != dev || seg2 != seg) {
+			/* New segment - need to make sure youth is correct */
+			dev = dev2;
+			seg = seg2;
+			/* if fs->checkpointing, seg_apply_all will do the youth
+			 * update
+			 */
+			if (fs->checkpointing == 0)
+				lafs_update_youth(fs, dev, seg);
+		}
+	}
 	put_page(p);
 	put_page(pg);
-	kfree(buf);
 
 	lafs_add_active(fs, next);
 
-- 
2.39.5