Date: Sat, 30 Jun 2001 07:53:37 +1000
From: Nathan Scott <nathans@sgi.com>
To: Roger Moore <rwmoore@fnal.gov>
Cc: linux-xfs@oss.sgi.com
Subject: [patch] Re: Label based mounts with fsck
Message-ID: <20010630075337.A165960@wobbly.melbourne.sgi.com>
References: <Pine.LNX.4.33.0106281638040.17083-100000@thwaite-clued0.fnal.gov>
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In-Reply-To: <Pine.LNX.4.33.0106281638040.17083-100000@thwaite-clued0.fnal.gov>; from rwmoore@fnal.gov on Thu, Jun 28, 2001 at 04:46:02PM -0500
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hi Roger,

On Thu, Jun 28, 2001 at 04:46:02PM -0500, Roger Moore wrote:
> Hi,
> 
> We've just updated our cluster to use XFS and have noticed a problem with
> using 'LABEL=xxx' in the fstab file.
> 
> The 'mount' command works fine with XFS labels (once you turn off devfs!).
> However the problem lies with the fsck command. The RedHat 7.1 system we
> have runs 'fsck -A...' at boot time which is needed for the remaining ext2
> partitions. This complains that it cannont find 'LABEL=xxx' for XFS
> partitions even when we configure /etc/fstab has f_passno=0 for the XFS
> mounts. Is there a patch out there for fsck to fix this problem?
> 

could you try the attached patch and let me know how it goes?
I think we're getting bitten by the use of DEFAULT_FSTYPE (ext2)
in the fsck_device() routine... this should fix that.

> We are currently using e2fsprogs-1.21 from RawHide since it is needed for
> the 2.4.5-0.2.9 RawHide kernel which you have patched.
> 

the patch is against e2fsprogs-1.22, but this code doesn't seem
to have changed for awhile and should patch cleanly to 1.21 too.

if it works, let me know & I'll forward on to Ted.

thanks.

-- 
Nathan

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diff -Naur e2fsprogs-1.22/misc/get_device_by_label.c e2fsprogs/misc/get_device_by_label.c
--- e2fsprogs-1.22/misc/get_device_by_label.c	Sat Jun 23 06:25:59 2001
+++ e2fsprogs/misc/get_device_by_label.c	Sat Jun 30 01:39:54 2001
@@ -48,6 +48,16 @@
 };
 #define ext2magic(s)    ((unsigned int) s.s_magic[0] + (((unsigned int) s.s_magic[1]) << 8))
 
+#define XFS_SUPER_MAGIC "XFSB"
+#define XFS_SUPER_MAGIC2 "BSFX"
+struct xfs_super_block {
+	unsigned char	s_magic[4];
+	unsigned char	s_dummy[28];
+	unsigned char	s_uuid[16];
+	unsigned char	s_dummy2[60];
+	unsigned char	s_fname[12];
+};
+
 static struct uuidCache_s {
 	struct uuidCache_s *next;
 	char uuid[16];
@@ -55,35 +65,44 @@
 	char *device;
 } *uuidCache = NULL;
 
-/* for now, only ext2 is supported */
+/* for now, only ext2 and xfs are supported */
 static int
 get_label_uuid(const char *device, char **label, char *uuid) {
 
-	/* start with a test for ext2, taken from mount_guess_fstype */
+	/* start with ext2 and xfs tests, taken from mount_guess_fstype */
 	/* should merge these later */
 	int fd;
+	int rv = 1;
+	size_t namesize;
 	struct ext2_super_block e2sb;
+	struct xfs_super_block xfsb;
 
 	fd = open(device, O_RDONLY);
 	if (fd < 0)
-		return 1;
+		return rv;
 
-	if (lseek(fd, 1024, SEEK_SET) != 1024
-	    || read(fd, (char *) &e2sb, sizeof(e2sb)) != sizeof(e2sb)
-	    || (ext2magic(e2sb) != EXT2_SUPER_MAGIC)) {
-		close(fd);
-		return 1;
+	if (lseek(fd, 1024, SEEK_SET) == 1024
+	    && read(fd, (char *) &e2sb, sizeof(e2sb)) == sizeof(e2sb)
+	    && (ext2magic(e2sb) == EXT2_SUPER_MAGIC)) {
+		memcpy(uuid, e2sb.s_uuid, sizeof(e2sb.s_uuid));
+		namesize = sizeof(e2sb.s_volume_name);
+		if ((*label = calloc(namesize + 1, 1)) != NULL)
+			memcpy(*label, e2sb.s_volume_name, namesize);
+		rv = 0;
+	}
+	else if (lseek(fd, 0, SEEK_SET) == 0
+	    && read(fd, (char *) &xfsb, sizeof(xfsb)) == sizeof(xfsb)
+	    && (strncmp((char *) &xfsb.s_magic, XFS_SUPER_MAGIC, 4) == 0 ||
+	        strncmp((char *) &xfsb.s_magic, XFS_SUPER_MAGIC2,4) == 0)) {
+		memcpy(uuid, xfsb.s_uuid, sizeof(xfsb.s_uuid));
+		namesize = sizeof(xfsb.s_fname);
+		if ((*label = calloc(namesize + 1, 1)) != NULL)
+			memcpy(*label, xfsb.s_fname, namesize);
+		rv = 0;
 	}
 
 	close(fd);
-
-	/* superblock is ext2 - now what is its label? */
-	memcpy(uuid, e2sb.s_uuid, sizeof(e2sb.s_uuid));
-
-	*label = calloc(sizeof(e2sb.s_volume_name) + 1, 1);
-	memcpy(*label, e2sb.s_volume_name, sizeof(e2sb.s_volume_name));
-
-	return 0;
+	return rv;
 }
 
 static void

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