[Ocfs2-tools-devel] [PATCH 1/1] ocfs2-tools: Add setting custom UUID in tunefs.ocfs2

[Sunil Mushran]

On 06/10/2010 09:08 AM, Tiger Yang wrote:
> This patch enhance uuid-reset operation to set custom UUID.
> The format of the UUID could be 32 bytes or 36 bytes.
> For example: 178BDC83D50241EF94EB474A677d498B or
> 178BDC83-D502-41EF-94EB-474A677D498B.
>    

We have been moving away from the traditional uuid format.
What do others think? Should we support both inputs? I am
inclined to support only the first input as that is what -Q "%U"
"stats" in debugfs.ocfs2, etc., returns.

> Signed-off-by: Tiger Yang<tiger.yang at oracle.com>
> ---
>   tunefs.ocfs2/ocfs2ne.c         |    8 +++--
>   tunefs.ocfs2/op_reset_uuid.c   |   74 +++++++++++++++++++++++++++++++++++++--
>   tunefs.ocfs2/tunefs.ocfs2.8.in |    4 +-
>   3 files changed, 77 insertions(+), 9 deletions(-)
>
> diff --git a/tunefs.ocfs2/ocfs2ne.c b/tunefs.ocfs2/ocfs2ne.c
> index 48760c6..51e07a8 100644
> --- a/tunefs.ocfs2/ocfs2ne.c
> +++ b/tunefs.ocfs2/ocfs2ne.c
> @@ -490,10 +490,12 @@ static struct tunefs_option list_sparse_option = {
>
>   static struct tunefs_option reset_uuid_option = {
>   	.opt_option	= {
> -		.name	= "uuid-reset",
> -		.val	= 'U',
> +		.name		= "uuid-reset",
> +		.val		= 'U',
> +		.has_arg	= 2,
>   	},
> -	.opt_help	= "-U|--uuid-reset",
> +	.opt_help	= "-U[new-uuid]|--uuid-reset[=new-uuid]",
> +	.opt_handle	=&generic_handle_arg,
>   	.opt_op		=&reset_uuid_op,
>    

+	.opt_help	= "-U|--uuid-reset [new-uuid]",


>   };
>
> diff --git a/tunefs.ocfs2/op_reset_uuid.c b/tunefs.ocfs2/op_reset_uuid.c
> index 25a21fb..ae15f1d 100644
> --- a/tunefs.ocfs2/op_reset_uuid.c
> +++ b/tunefs.ocfs2/op_reset_uuid.c
> @@ -27,8 +27,26 @@
>
>   #include "libocfs2ne.h"
>
> +/*
> + *	Translate 32 bytes uuid to 36 bytes uuid format.
> + *	for example:
> + *	32 bytes uuid: 178BDC83D50241EF94EB474A677D498B
> + *	36 bytes uuid: 178BDC83-D502-41EF-94EB-474A677D498B
> + */
> +static void uuid_translate(char *uuid_32, char *uuid_36)
> +{
> +	int i;
> +	char *cp = uuid_32;
> +	for (i = 0; i<  36; i++) {
> +		if ((i == 8) || (i == 13) || (i == 18) || (i == 23)) {
> +			uuid_36[i] = '-';
> +			continue;
> +		}
> +		uuid_36[i] = *cp++;
> +	}
> +}
>
> -static errcode_t update_volume_uuid(ocfs2_filesys *fs)
> +static errcode_t update_volume_uuid(ocfs2_filesys *fs, char *uuid)
>   {
>   	errcode_t err;
>   	unsigned char new_uuid[OCFS2_VOL_UUID_LEN];
> @@ -42,7 +60,19 @@ static errcode_t update_volume_uuid(ocfs2_filesys *fs)
>   	if (!prog)
>   		return TUNEFS_ET_NO_MEMORY;
>
> -	uuid_generate(new_uuid);
> +	if (uuid == NULL)
> +		uuid_generate(new_uuid);
> +	else {
> +		if (strlen(uuid) == 32) {
> +			char uuid_36[37] = {'\0'};
> +
> +			/*translate 32 bytes uuid to 36 bytes uuid*/
> +			uuid_translate(uuid, uuid_36);
> +			/*uuid_parse only support 36 bytes uuid*/
> +			uuid_parse(uuid_36, new_uuid);
> +		} else
> +			uuid_parse(uuid, new_uuid);
> +	}
>   	memcpy(OCFS2_RAW_SB(fs->fs_super)->s_uuid, new_uuid,
>   	       OCFS2_VOL_UUID_LEN);
>
> @@ -55,13 +85,49 @@ static errcode_t update_volume_uuid(ocfs2_filesys *fs)
>   	return err;
>   }
>
> +static int reset_uuid_parse_option(struct tunefs_operation *op, char *arg)
> +{
> +	int i;
> +	char *cp = arg;
> +	int len;
> +
> +	if (arg == NULL)
> +		goto out;
> +
> +	len = strlen(arg);
> +	/*check the uuid length, we support 32/36 bytes uuid format*/
> +	if (len != 32&&  len != 36)
> +		goto bail;
> +
> +	/*check wheter each character of uuid is a hexadecimal digit*/
> +	for (i = 0; i<  len; i++, cp++) {
> +		if (len == 36) {
> +			if ((i == 8) || (i == 13) || (i == 18) || (i == 23)) {
> +				if (*cp == '-')
> +					continue;
> +				else
> +					goto bail;
> +			}
> +		}
> +		if (!isxdigit(*cp))
> +			goto bail;
> +	}
> +out:
> +	op->to_private = arg;
> +	return 0;
> +bail:
> +	errorf("Invalid UUID\n");
> +	return 1;
> +}
> +
>   static int reset_uuid_run(struct tunefs_operation *op, ocfs2_filesys *fs,
>   			  int flags)
>   {
>   	int rc = 0;
>   	errcode_t err;
> +	char *uuid = op->to_private;
>
> -	err = update_volume_uuid(fs);
> +	err = update_volume_uuid(fs, uuid);
>   	if (err) {
>   		tcom_err(err, "- unable to reset the uuid on device \"%s\"",
>   			 fs->fs_devname);
> @@ -75,7 +141,7 @@ static int reset_uuid_run(struct tunefs_operation *op, ocfs2_filesys *fs,
>   DEFINE_TUNEFS_OP(reset_uuid,
>   		 "Usage: op_reset_uuid [opts]<device>\n",
>   		 TUNEFS_FLAG_RW,
> -		 NULL,
> +		 reset_uuid_parse_option,
>   		 reset_uuid_run);
>
>   #ifdef DEBUG_EXE
> diff --git a/tunefs.ocfs2/tunefs.ocfs2.8.in b/tunefs.ocfs2/tunefs.ocfs2.8.in
> index 3bebd41..5f7c237 100644
> --- a/tunefs.ocfs2/tunefs.ocfs2.8.in
> +++ b/tunefs.ocfs2/tunefs.ocfs2.8.in
> @@ -78,8 +78,8 @@ printf(3) type formatters. The list of type specifiers is as follows:
>   Quiet mode.
>
>   .TP
> -\fB\-U, \-\-uuid\-reset\fR
> -Change the volume UUID (auto-generated) for the file system.
> +\fB\-U, \-\-uuid\-reset\fR[=\fInew-uuid]\fR
> +Set the volume UUID for the file system. If not provided, will auto generate a new UUID. The format of the provided UUID should be 178BDC83D50241EF94EB474A677D498B or 178BDC83-D502-41EF-94EB-474A677D498B.
>
>   .TP
>   \fB\-v, \-\-verbose\fR
>    

Also, we probably need to add a warning whenever a user chooses
to provide a UUID.

"WARNING!!! OCFS2 uses the UUID to uniquely identify a
file system. Having two OCFS2 file systems with the same
UUID could, in the least, cause erratic behavior, and if unlucky,
cause file system damage. Please choose the UUID with care."