[PATCH] JFS external journal support

Additional support for external journal.  We're basically adding uuid's
to both the file system and the journal to tie the two together.

fs/jfs/jfs_incore.h

@@ -122,8 +122,11 @@ struct jfs_sb_info {
 	short		l2nbperpage;	/* 2: log2 blocks per page	*/
 	short		l2niperblk;	/* 2: log2 inodes per page	*/
 	kdev_t		logdev;		/* 2: external log device	*/
+	uint		aggregate;	/* volume identifier in log record */
 	pxd_t		logpxd;		/* 8: pxd describing log	*/
 	pxd_t		ait2;		/* 8: pxd describing AIT copy	*/
+	char		uuid[16];	/* 16: 128-bit uuid for volume	*/
+	char		loguuid[16];	/* 16: 128-bit uuid for log	*/
 	/* Formerly in ipimap */
 	uint		gengen;		/* 4: inode generation generator*/
 	uint		inostamp;	/* 4: shows inode belongs to fileset*/

fs/jfs/jfs_logmgr.c

@@ -168,7 +168,7 @@ static int lmWriteRecord(log_t * log, tblock_t * tblk, lrd_t * lrd,
 			 tlock_t * tlck);
 
 static int lmNextPage(log_t * log);
-static int lmLogFileSystem(log_t * log, kdev_t fsdev, int activate);
+static int lmLogFileSystem(log_t * log, char *uuid, int activate);
 static int lmLogInit(log_t * log);
 static int lmLogShutdown(log_t * log);
 
@@ -1098,6 +1098,11 @@ int lmLogOpen(struct super_block *sb, log_t ** logptr)
 	 * file systems to log may have n-to-1 relationship;
 	 */
       externalLog:
+
+	/*
+	 * TODO: Check for already opened log devices
+	 */
+
 	if (!(bdev = bdget(kdev_t_to_nr(JFS_SBI(sb)->logdev)))) {
 		rc = ENODEV;
 		goto errout10;
@@ -1110,6 +1115,7 @@ int lmLogOpen(struct super_block *sb, log_t ** logptr)
 
 	log->sb = sb;		/* This should be a list */
 	log->bdev = bdev;
+	memcpy(log->uuid, JFS_SBI(sb)->loguuid, sizeof(log->uuid));
 	
 	/*
 	 * initialize log:
@@ -1120,7 +1126,7 @@ int lmLogOpen(struct super_block *sb, log_t ** logptr)
 	/*
 	 * add file system to log active file system list
 	 */
-	if ((rc = lmLogFileSystem(log, sb->s_dev, 1)))
+	if ((rc = lmLogFileSystem(log, JFS_SBI(sb)->uuid, 1)))
 		goto errout30;
 
       out:
@@ -1221,6 +1227,10 @@ static int lmLogInit(log_t * log)
 		     ("lmLogInit: inline log:0x%p base:0x%Lx size:0x%x\n",
 		      log, (unsigned long long) log->base, log->size));
 	} else {
+		if (memcmp(logsuper->uuid, log->uuid, 16)) {
+			jERROR(1,("wrong uuid on JFS log device\n"));
+			goto errout20;
+		}
 		log->size = le32_to_cpu(logsuper->size);
 		log->l2bsize = le32_to_cpu(logsuper->l2bsize);
 		jFYI(0,
@@ -1317,7 +1327,6 @@ static int lmLogInit(log_t * log)
 	logsuper->state = cpu_to_le32(LOGMOUNT);
 	log->serial = le32_to_cpu(logsuper->serial) + 1;
 	logsuper->serial = cpu_to_le32(log->serial);
-	logsuper->device = cpu_to_le32(log->bdev->bd_dev);
 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
 	if ((rc = lbmIOWait(bpsuper, lbmFREE)))
 		goto errout30;
@@ -1374,7 +1383,7 @@ int lmLogClose(struct super_block *sb, log_t * log)
 	 *      external log as separate logical volume
 	 */
       externalLog:
-	lmLogFileSystem(log, sb->s_dev, 0);
+	lmLogFileSystem(log, JFS_SBI(sb)->uuid, 0);
 	rc = lmLogShutdown(log);
 	blkdev_put(log->bdev, BDEV_FS);
 
@@ -1509,11 +1518,10 @@ static int lmLogShutdown(log_t * log)
  *			
  * serialization: IWRITE_LOCK(log inode) held on entry/exit
  */
-static int lmLogFileSystem(log_t * log, kdev_t fsdev, int activate)
+static int lmLogFileSystem(log_t * log, char *uuid, int activate)
 {
 	int rc = 0;
 	int i;
-	u32 dev_le = cpu_to_le32(kdev_t_to_nr(fsdev));
 	logsuper_t *logsuper;
 	lbuf_t *bpsuper;
 
@@ -1526,8 +1534,8 @@ static int lmLogFileSystem(log_t * log, kdev_t fsdev, int activate)
 	logsuper = (logsuper_t *) bpsuper->l_ldata;
 	if (activate) {
 		for (i = 0; i < MAX_ACTIVE; i++)
-			if (logsuper->active[i] == 0) {
-				logsuper->active[i] = dev_le;
+			if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
+				memcpy(logsuper->active[i].uuid, uuid, 16);
 				break;
 			}
 		if (i == MAX_ACTIVE) {
@@ -1537,8 +1545,8 @@ static int lmLogFileSystem(log_t * log, kdev_t fsdev, int activate)
 		}
 	} else {
 		for (i = 0; i < MAX_ACTIVE; i++)
-			if (logsuper->active[i] == dev_le) {
-				logsuper->active[i] = 0;
+			if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
+				memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
 				break;
 			}
 		assert(i < MAX_ACTIVE);

fs/jfs/jfs_logmgr.h

@@ -58,7 +58,7 @@
 #define	LOGMAGIC	0x87654321
 #define	LOGVERSION	1
 
-#define MAX_ACTIVE	512	/* Max active file systems sharing log */
+#define MAX_ACTIVE	128	/* Max active file systems sharing log */
 
 typedef struct {
 	u32 magic;		/* 4: log lv identifier */
@@ -72,10 +72,15 @@ typedef struct {
 	u32 state;		/* 4: state - see below */
 
 	s32 end;		/* 4: addr of last log record set by logredo */
-	u32 device;		/* 4: save device in case location changes */
-	u32 active[MAX_ACTIVE];	/* 2048: active file systems list */
+	char uuid[16];		/* 16: 128-bit journal uuid */
+	char label[16];		/* 16: journal label */
+	struct {
+		char uuid[16];
+	} active[MAX_ACTIVE];	/* 2048: active file systems list */
 } logsuper_t;
 
+#define NULL_UUID "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
+
 /* log flag: commit option (see jfs_filsys.h) */
 
 /* log state */
@@ -411,6 +416,7 @@ typedef struct jfs_log {
 	spinlock_t synclock;	/* 4: synclist lock */
 	struct lbuf *wqueue;	/* 4: log pageout queue */
 	int count;		/* 4: count */
+	char uuid[16];		/* 16: 128-bit uuid of log device */
 } log_t;
 
 /*

fs/jfs/jfs_mount.c

@@ -405,8 +405,11 @@ static int chkSuper(struct super_block *sb)
 	sbi->l2niperblk = sbi->l2bsize - L2DISIZE;
 	if (sbi->mntflag & JFS_INLINELOG)
 		sbi->logpxd = j_sb->s_logpxd;
-	else
+	else {
 		sbi->logdev = to_kdev_t(le32_to_cpu(j_sb->s_logdev));
+		memcpy(sbi->uuid, j_sb->s_uuid, sizeof(sbi->uuid));
+		memcpy(sbi->loguuid, j_sb->s_loguuid, sizeof(sbi->uuid));
+	}
 	sbi->ait2 = j_sb->s_ait2;
 
       out:
@@ -446,10 +449,6 @@ int updateSuper(struct super_block *sb, uint state)
 		j_sb->s_logdev =
 			cpu_to_le32(JFS_SBI(sb)->log->bdev->bd_dev);
 		j_sb->s_logserial = cpu_to_le32(JFS_SBI(sb)->log->serial);
-		/* record our own device number in case the location
-		 * changes after a reboot
-		 */
-		j_sb->s_device = cpu_to_le32(kdev_t_to_nr(sb->s_dev));
 	} else if (state == FM_CLEAN) {
 		/*
 		 * If this volume is shared with OS/2, OS/2 will need to

fs/jfs/jfs_superblock.h

@@ -91,6 +91,7 @@ struct jfs_superblock {
 				 *     N.B. This must be 11 bytes to
 				 *          conform with the OS/2 BootSector
 				 *          requirements
+				 *          Only used when s_version is 1
 				 */
 
 	/* extendfs() parameter under s_state & FM_EXTENDFS */
@@ -99,9 +100,9 @@ struct jfs_superblock {
 	pxd_t s_xlogpxd;	/* 8: extendfs logpxd */
 	/* - 128 byte boundary - */
 
-	u32 s_device;		/* Store device in case location changes
-				 * between reboots
-				 */
+	char s_uuid[16];	/* 16: 128-bit uuid for volume */
+	char s_label[16];	/* 16: volume label */
+	char s_loguuid[16];	/* 16: 128-bit uuid for log device */
 
 };