From d7cd998fc8a23a107bc15f29d6aa1ecd7666580d Mon Sep 17 00:00:00 2001
From: braam <braam>
Date: Thu, 2 Dec 1999 00:11:46 +0000
Subject: [PATCH] Updated snapshot indexes in superblock to not depend on index
 "0" as being the current snapshot.  We still need to push the inode
 attributes to the snap copy so that size/times are correct.

---
 lustre/include/linux/obd_snap.h | 13 ++++++++++++-
 lustre/obdclass/obdcontrol      | 28 +++++++++++++++++++++++-----
 lustre/obdfs/super.c            |  7 +++++++
 3 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/lustre/include/linux/obd_snap.h b/lustre/include/linux/obd_snap.h
index cf03c00..4289bac 100644
--- a/lustre/include/linux/obd_snap.h
+++ b/lustre/include/linux/obd_snap.h
@@ -4,11 +4,17 @@
 #define OBD_SNAP_MAGIC 0x47224722
 
 #define SNAP_MAX  8 /* must fit in "u" area of struct inode */
+
+/* if time is 0 this designates the "current" snapshot, i.e.
+   the head of the tree 
+*/
+
 struct snap {
 	time_t time;
 	int index;
 };
 
+/* snap ioctl data for attach */
 struct snap_obd_data {
 	int snap_dev;             /* which device contains the data */
 	unsigned int snap_no;     /* which snapshot are we accessing */
@@ -16,13 +22,18 @@ struct snap_obd_data {
 	struct snap snap_snaps[SNAP_MAX]; /* times must be incr or attach will fail */
 };
 
+
+/* this is the obd device descriptor */
 struct snap_obd {
-	unsigned int snap_no;    /* which snapshot are we accessing */
+	unsigned int snap_no;    /* which snapshot index are we accessing */
+	unsigned int snap_current;
 	unsigned int snap_count; /* how many snapshots exist */
 	time_t snap_times[SNAP_MAX];
 	int snap_index[SNAP_MAX];
 };
 
+
+/* stored as inline data in the objects */
 struct snap_object_data {
 	int od_magic;
 	/* id of snaps of object; slot 0 has the current data */
diff --git a/lustre/obdclass/obdcontrol b/lustre/obdclass/obdcontrol
index a399b7e..e866cc6 100755
--- a/lustre/obdclass/obdcontrol
+++ b/lustre/obdclass/obdcontrol
@@ -307,6 +307,11 @@ sub SnapAttach {
 
     $snapcount = keys %{$table};
     print "Snapcount $snapcount\n";
+
+    if ( ! defined $table->{0} ) {
+	print "No current snapshot in table! First make one\n";
+	return ;
+    }
     $data = pack("iii", $snapdev, $snapno, $snapcount);
     $datalen = 3 * 4;
     foreach my $time (sort keys %{$table}) {
@@ -318,7 +323,6 @@ sub SnapAttach {
     my $cl = length($data);
     my $add = pack("p", $data);
     print "type $type (len $len), datalen $datalen ($cl)\n";
-    printf "Addr of data %x\n", $add; 
     my $packed = pack("ipip", length($type), $type, $datalen, $data);
 
     my $rc = ioctl(DEV_OBD, &OBD_IOC_ATTACH, $packed);
@@ -350,11 +354,19 @@ sub SnapShotTable  {
     goto again;
 
   add:
-    my $idx = &readl("enter new index: ");
-    my $time = &readl("enter time (hit RET for \"now\"): ");
+    my $idx = &readl("enter index where you want this snapshot: ");
+    my $time = &readl("enter time or 'now' or 'current': ");
     my $oldtime = SnapFindTimeFromIdx($idx, $table);
-    delete $table->{$oldtime} if defined $oldtime;
-    $time = time unless $time;
+    if (defined $oldtime) {
+	print "This already exists, first clean up\n";
+	goto again;
+    }
+
+    if ( $time  eq 'now' ) {
+	$time = time;
+    } elsif ( $time eq 'current' ) { 
+	$time = 0;
+    }
     $table->{$time} = $idx;
     goto again;
 
@@ -389,6 +401,9 @@ sub PrintSnapShotTable {
     
     foreach  $time ( sort keys %{$table} ) {
 	my $stime = localtime($time);
+	if ( ! $time ) { 
+	    $stime = "current";
+	}
 	printf "Time: %s -- Index %d\n", $stime, $table->{$time};
     }
 }
@@ -404,6 +419,9 @@ sub ReadSnapShotTable {
 	$table->{$time} = $index;
     }
     close FH;
+
+    PrintSnapShotTable($table);
+
     return $table;
 }
 
diff --git a/lustre/obdfs/super.c b/lustre/obdfs/super.c
index f8c5415..a58949a 100644
--- a/lustre/obdfs/super.c
+++ b/lustre/obdfs/super.c
@@ -146,24 +146,28 @@ static struct super_block * obdfs_read_super(struct super_block *sb,
 	if ( !device ) {
 		printk("No device\n");
 		MOD_DEC_USE_COUNT;
+		EXIT;
 		return NULL;
 	}
 
 	if ( (err = obdfs_getdev(device, &devno)) ) {
 		printk("Cannot get devno of %s, error %d\n", device, err);
 		MOD_DEC_USE_COUNT;
+		EXIT;
 		return NULL;
 	}
 
 	if ( MAJOR(devno) != OBD_PSDEV_MAJOR ) {
 		printk("Wrong major number!\n");
 		MOD_DEC_USE_COUNT;
+		EXIT;
 		return NULL;
 	}
 		
 	if ( MINOR(devno) >= MAX_OBD_DEVICES ) {
 		printk("Minor of %s too high (%d)\n", device, MINOR(devno));
 		MOD_DEC_USE_COUNT;
+		EXIT;
 		return NULL;
 	} 
 
@@ -171,7 +175,10 @@ static struct super_block * obdfs_read_super(struct super_block *sb,
 
 	if ( ! (obddev->obd_flags & OBD_ATTACHED) || 
 	     ! (obddev->obd_flags & OBD_SET_UP) ){
+		printk("Device %s not attached or not set up (%d)\n", 
+		       device, MINOR(devno));
 		MOD_DEC_USE_COUNT;
+		EXIT;
 		return NULL;
 	} 
 
-- 
1.8.3.1