From: NeilBrown <neilb@suse.de>
Date: Wed, 4 May 2011 03:47:01 +0000 (+1000)
Subject: FORMAT CHANGE add timestamp to group head in write cluster
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=f6faab308e1171d30a6b5623b3123a32bf74d5c9;p=LaFS.git

FORMAT CHANGE add timestamp to group head in write cluster

This allows accurate preservation of timestamps during
roll forward.

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

diff --git a/cluster.c b/cluster.c
index 6233fb8..57fa6a6 100644
--- a/cluster.c
+++ b/cluster.c
@@ -801,7 +801,7 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 		int avail;
 		/* see how much room is in cluster.
 		 * The interesting values are:
-		 * none, one descriptor, one grouphead and one descriptor
+		 * none, one descriptor, one group_head and one descriptor
 		 * These are assigned values 0, 1, 2.
 		 */
 		if (wc->cluster_space >= (sizeof(struct group_head) +
@@ -871,11 +871,20 @@ static void cluster_addhead(struct wc *wc, struct inode *ino,
 	struct group_head *gh = (struct group_head *)((char *)wc->chead +
 						      wc->chead_size);
 	u16 tnf;
+	u64 tstamp;
 	dprintk("CLUSTER addhead %d\n", wc->chead_size);
 	*headstart = gh;
 
 	gh->inum = cpu_to_le32(ino->i_ino);
 	gh->fsnum = cpu_to_le32(LAFSI(ino)->filesys->i_ino);
+	if (LAFSI(ino)->type >= TypeBase) {
+		tstamp = encode_time(&ino->i_mtime);
+		if (tstamp != encode_time(&ino->i_ctime))
+			tstamp = 0;
+	} else
+		tstamp = 0;
+	gh->timestamp = cpu_to_le64(tstamp);
+
 	tnf = ((ino->i_generation<<8) | (LAFSI(ino)->trunc_gen & 0xff))
 		& 0x7fff;
 	if (wc->cnum)
diff --git a/layout.h b/layout.h
index afa81ed..0095097 100644
--- a/layout.h
+++ b/layout.h
@@ -81,6 +81,9 @@ struct miniblock {
 struct group_head {
 	u32	inum;
 	u32	fsnum;
+	u64	timestamp;	/* If non-zero, the ctime and mtime
+				 * of the file should be set to this.
+				 */
 	u16	truncatenum_and_flag;
 	u16	group_size_words;	/* 4byte words */
 	union {
diff --git a/roll.c b/roll.c
index e8ebbba..7b82acd 100644
--- a/roll.c
+++ b/roll.c
@@ -394,7 +394,7 @@ roll_mini(struct fs *fs, int fsnum, int inum, int trunc,
 
 static int __must_check
 roll_block(struct fs *fs, int fsnum, int inum, int trunc,
-	   u32 bnum, u64 baddr, int bytes, struct page *p)
+	   u32 bnum, u64 baddr, int bytes, u64 tstamp, struct page *p)
 {
 	struct inode *inode;
 	struct datablock *blk = NULL;
@@ -492,6 +492,11 @@ roll_block(struct fs *fs, int fsnum, int inum, int trunc,
 			inode->i_size = ((loff_t)bnum << inode->i_blkbits) + bytes;
 			set_bit(I_Dirty, &LAFSI(inode)->iflags);
 		}
+		if (tstamp) {
+			decode_time(&inode->i_mtime, tstamp);
+			decode_time(&inode->i_ctime, tstamp);
+			set_bit(I_Dirty, &LAFSI(inode)->iflags);
+		}
 
 		/* FIXME: we pretend this is a dirty, pinned block
 		 * so the lower-level code doesn't get confused.
@@ -600,6 +605,7 @@ roll_one(struct fs *fs, u64 *addrp, struct page *p, struct page *pg,
 		int fsnum = le32_to_cpu(gh->fsnum);
 		int trunc = le16_to_cpu(gh->truncatenum_and_flag) & 0x7fff;
 		int flg   = le16_to_cpu(gh->truncatenum_and_flag) & 0x8000;
+		u64 tstamp = le64_to_cpu(gh->timestamp);
 
 		desc = gh->u.desc;
 		while (((char *)desc - (char *)gh) <
@@ -634,6 +640,7 @@ roll_one(struct fs *fs, u64 *addrp, struct page *p, struct page *pg,
 								 cnt == 0 || bytes == DescHole
 								 ? bytes
 								 : blocksize,
+								 tstamp,
 								 pg);
 					bnum++;
 				}