diff mbox

Btrfs-progs: add UUID switches to mkfs and convert

Message ID 1357486331-4615-2-git-send-email-falbrechtskirchinger@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Florian Albrechtskirchinger Jan. 6, 2013, 3:32 p.m. UTC
Add the following switches to mkfs.btrfs and update man page:
* -U UUID, --uuid UUID

Add the following switches to btrfs-convert:
* -U UUID
* -U new
  Generates a random UUID (default behavior).
* -U copy
  Copies the UUID from the ext2fs.

Signed-off-by: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
---
 convert.c           | 48 ++++++++++++++++++++++++++++++++++++++++--------
 man/mkfs.btrfs.8.in |  4 ++++
 mkfs.c              | 20 ++++++++++++++++++--
 utils.c             |  6 +++---
 utils.h             |  4 ++--
 5 files changed, 67 insertions(+), 15 deletions(-)

Comments

David Sterba Jan. 14, 2013, 10:53 p.m. UTC | #1
On Sun, Jan 06, 2013 at 04:32:11PM +0100, Florian Albrechtskirchinger wrote:
> Add the following switches to mkfs.btrfs and update man page:
> * -U UUID, --uuid UUID
> 
> Add the following switches to btrfs-convert:
> * -U UUID
> * -U new
>   Generates a random UUID (default behavior).
> * -U copy
>   Copies the UUID from the ext2fs.

Sounds useful, thanks. There are minor comments to the
documentation/help strings.

More than one filesystem with the same UUID brings trouble when mounting
by UUID, a check that would at least warn that there are more such
filesystems would be good. This should catch easy & silly copy-paste
errors.

> --- a/convert.c
> +++ b/convert.c
> @@ -2752,23 +2759,28 @@ fail:
>  
>  static void print_usage(void)
>  {
> -	printf("usage: btrfs-convert [-d] [-i] [-n] [-r] device\n");
> +	printf("usage: btrfs-convert [-d] [-i] [-n] [-r]"
> +	       " [-U UUID | new | copy] device\n");
>  	printf("\t-d disable data checksum\n");
>  	printf("\t-i ignore xattrs and ACLs\n");
>  	printf("\t-n disable packing of small files\n");
>  	printf("\t-r roll back to ext2fs\n");
> +	printf("\t-U UUID specify FS UUID\n");
> +	printf("\t-U new generate random FS UUID (default)\n");
> +	printf("\t-U copy copy FS UUID from ext2fs\n");

From this is not clear that 'new' and 'copy' should be typed verbatim
(ie.  that it's not part of the help text), the expected format of the
UUID like "specify FS UUID in canonical format'.

>  }
>  
> --- a/mkfs.c
> +++ b/mkfs.c
> @@ -347,6 +347,7 @@ static void print_usage(void)
>  	fprintf(stderr, "\t -M --mixed mix metadata and data together\n");
>  	fprintf(stderr, "\t -n --nodesize size of btree nodes\n");
>  	fprintf(stderr, "\t -s --sectorsize min block allocation\n");
> +	fprintf(stderr, "\t -U --uuid FS UUID\n");

maybe a little bit enhanced with the 'in canonical format'.

>  	fprintf(stderr, "\t -r --rootdir the source directory\n");
>  	fprintf(stderr, "\t -K --nodiscard do not perform whole device TRIM\n");
>  	fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
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David Sterba Feb. 27, 2013, 4:43 p.m. UTC | #2
On Sun, Jan 06, 2013 at 04:32:11PM +0100, Florian Albrechtskirchinger wrote:
> Add the following switches to mkfs.btrfs and update man page:
> * -U UUID, --uuid UUID
> 
> Add the following switches to btrfs-convert:
> * -U UUID
> * -U new
>   Generates a random UUID (default behavior).
> * -U copy
>   Copies the UUID from the ext2fs.

Can you please enhance it with a check that the UUID is not duplicate
among other filesystems? It should be available throgh libblkid:

	blkid_probe_lookup_value(probe, "UUID", &uuid, NULL);

This is a sort of paranoia check with the generated UUID, but I think
that an accidentally repeated command or copy&paste with an existing
uuid can happen.

thanks,
david
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diff mbox

Patch

diff --git a/convert.c b/convert.c
index fa7bf8c..67c8a87 100644
--- a/convert.c
+++ b/convert.c
@@ -2272,9 +2272,11 @@  err:
 	return ret;
 }
 
-int do_convert(const char *devname, int datacsum, int packing, int noxattr)
+int do_convert(const char *devname, int copy_fsid, u8 fsid[BTRFS_UUID_SIZE],
+	       int datacsum, int packing, int noxattr)
 {
 	int i, fd, ret;
+	u8 *fsid_ptr;
 	u32 blocksize;
 	u64 blocks[7];
 	u64 total_bytes;
@@ -2313,9 +2315,14 @@  int do_convert(const char *devname, int datacsum, int packing, int noxattr)
 		fprintf(stderr, "unable to open %s\n", devname);
 		goto fail;
 	}
+	if (copy_fsid) {
+		fsid_ptr = ext2_fs->super->s_uuid;
+	} else {
+		fsid_ptr = fsid;
+	}
 	ret = make_btrfs(fd, devname, ext2_fs->super->s_volume_name,
-			 blocks, total_bytes, blocksize, blocksize,
-			 blocksize, blocksize);
+			 fsid_ptr, blocks, total_bytes,
+			 blocksize, blocksize, blocksize, blocksize);
 	if (ret) {
 		fprintf(stderr, "unable to create initial ctree\n");
 		goto fail;
@@ -2752,23 +2759,28 @@  fail:
 
 static void print_usage(void)
 {
-	printf("usage: btrfs-convert [-d] [-i] [-n] [-r] device\n");
+	printf("usage: btrfs-convert [-d] [-i] [-n] [-r]"
+	       " [-U UUID | new | copy] device\n");
 	printf("\t-d disable data checksum\n");
 	printf("\t-i ignore xattrs and ACLs\n");
 	printf("\t-n disable packing of small files\n");
 	printf("\t-r roll back to ext2fs\n");
+	printf("\t-U UUID specify FS UUID\n");
+	printf("\t-U new generate random FS UUID (default)\n");
+	printf("\t-U copy copy FS UUID from ext2fs\n");
 }
 
 int main(int argc, char *argv[])
 {
-	int ret;
+	int ret, copy_fsid = 0;
 	int packing = 1;
 	int noxattr = 0;
 	int datacsum = 1;
 	int rollback = 0;
-	char *file;
+	char *file, *fsid_str = NULL;
+	u8 fsid[BTRFS_UUID_SIZE];
 	while(1) {
-		int c = getopt(argc, argv, "dinr");
+		int c = getopt(argc, argv, "dinrU:");
 		if (c < 0)
 			break;
 		switch(c) {
@@ -2784,6 +2796,9 @@  int main(int argc, char *argv[])
 			case 'r':
 				rollback = 1;
 				break;
+			case 'U':
+				fsid_str = optarg;
+				break;
 			default:
 				print_usage();
 				return 1;
@@ -2801,10 +2816,27 @@  int main(int argc, char *argv[])
 		return 1;
 	}
 
+	if (fsid_str) {
+		if (strcmp(fsid_str, "new") == 0) {
+			uuid_generate(fsid);
+		} else if (strcmp(fsid_str, "copy") == 0) {
+			copy_fsid = 1;
+		} else {
+			if (uuid_parse(fsid_str, fsid) == -1) {
+				fprintf(stderr, "failed to parse UUID: %s\n",
+					fsid_str);
+				return 1;
+			}
+		}
+	} else {
+		uuid_generate(fsid);
+	}
+
 	if (rollback) {
 		ret = do_rollback(file, 0);
 	} else {
-		ret = do_convert(file, datacsum, packing, noxattr);
+		ret = do_convert(file, copy_fsid, fsid, datacsum, packing,
+				 noxattr);
 	}
 	if (ret)
 		return 1;
diff --git a/man/mkfs.btrfs.8.in b/man/mkfs.btrfs.8.in
index 72025ed..73abcc0 100644
--- a/man/mkfs.btrfs.8.in
+++ b/man/mkfs.btrfs.8.in
@@ -12,6 +12,7 @@  mkfs.btrfs \- create a btrfs filesystem
 [ \fB\-M\fP\fI mixed data+metadata\fP ]
 [ \fB\-n\fP\fI nodesize\fP ]
 [ \fB\-s\fP\fI sectorsize\fP ]
+[ \fB\-U\fP\fI UUID\fP ]
 [ \fB\-r\fP\fI rootdir\fP ]
 [ \fB\-K\fP ]
 [ \fB\-h\fP ]
@@ -61,6 +62,9 @@  Specify the nodesize. By default the value is set to the pagesize.
 \fB\-s\fR, \fB\-\-sectorsize \fIsize\fR
 Specify the sectorsize, the minimum block allocation.
 .TP
+\fB\-U\fR, \fB\-\-uuid \fIUUID\fR
+Specify the UUID for the filesystem.
+.TP
 \fB\-r\fR, \fB\-\-rootdir \fIrootdir\fR
 Specify a directory to copy into the newly created fs.
 .TP
diff --git a/mkfs.c b/mkfs.c
index 47f0c9c..1bdb0d3 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -347,6 +347,7 @@  static void print_usage(void)
 	fprintf(stderr, "\t -M --mixed mix metadata and data together\n");
 	fprintf(stderr, "\t -n --nodesize size of btree nodes\n");
 	fprintf(stderr, "\t -s --sectorsize min block allocation\n");
+	fprintf(stderr, "\t -U --uuid FS UUID\n");
 	fprintf(stderr, "\t -r --rootdir the source directory\n");
 	fprintf(stderr, "\t -K --nodiscard do not perform whole device TRIM\n");
 	fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
@@ -407,6 +408,7 @@  static struct option long_options[] = {
 	{ "mixed", 0, NULL, 'M' },
 	{ "nodesize", 1, NULL, 'n' },
 	{ "sectorsize", 1, NULL, 's' },
+	{ "uuid", 1, NULL, 'U' },
 	{ "data", 1, NULL, 'd' },
 	{ "version", 0, NULL, 'V' },
 	{ "rootdir", 1, NULL, 'r' },
@@ -1229,6 +1231,8 @@  int main(int ac, char **av)
 	struct btrfs_trans_handle *trans;
 	char *label = NULL;
 	char *first_file;
+	char *fsid_str = NULL;
+	u8 fsid[BTRFS_FSID_SIZE];
 	u64 block_count = 0;
 	u64 dev_block_count = 0;
 	u64 blocks[7];
@@ -1258,7 +1262,7 @@  int main(int ac, char **av)
 
 	while(1) {
 		int c;
-		c = getopt_long(ac, av, "A:b:l:n:s:m:d:L:r:VMK", long_options,
+		c = getopt_long(ac, av, "A:b:l:n:s:m:d:L:U:r:VMK", long_options,
 				&option_index);
 		if (c < 0)
 			break;
@@ -1288,6 +1292,9 @@  int main(int ac, char **av)
 			case 's':
 				sectorsize = parse_size(optarg);
 				break;
+			case 'U':
+				fsid_str = optarg;
+				break;
 			case 'b':
 				block_count = parse_size(optarg);
 				if (block_count <= 1024*1024*1024) {
@@ -1375,13 +1382,22 @@  int main(int ac, char **av)
 		}
 	}
 
+	if(fsid_str) {
+		if(uuid_parse(fsid_str, fsid) == -1) {
+			fprintf(stderr, "failed to parse UUID: %s\n", fsid_str);
+			exit(1);
+		}
+	}
+	else
+		uuid_generate(fsid);
+
 	blocks[0] = BTRFS_SUPER_INFO_OFFSET;
 	for (i = 1; i < 7; i++) {
 		blocks[i] = BTRFS_SUPER_INFO_OFFSET + 1024 * 1024 +
 			leafsize * i;
 	}
 
-	ret = make_btrfs(fd, file, label, blocks, dev_block_count,
+	ret = make_btrfs(fd, file, label, fsid, blocks, dev_block_count,
 			 nodesize, leafsize,
 			 sectorsize, stripesize);
 	if (ret) {
diff --git a/utils.c b/utils.c
index 205e667..1ef6174 100644
--- a/utils.c
+++ b/utils.c
@@ -74,8 +74,8 @@  static u64 reference_root_table[] = {
 };
 
 int make_btrfs(int fd, const char *device, const char *label,
-	       u64 blocks[7], u64 num_bytes, u32 nodesize,
-	       u32 leafsize, u32 sectorsize, u32 stripesize)
+	       u8 fsid[BTRFS_FSID_SIZE], u64 blocks[7], u64 num_bytes,
+	       u32 nodesize, u32 leafsize, u32 sectorsize, u32 stripesize)
 {
 	struct btrfs_super_block super;
 	struct extent_buffer *buf;
@@ -103,7 +103,7 @@  int make_btrfs(int fd, const char *device, const char *label,
 	memset(&super, 0, sizeof(super));
 
 	num_bytes = (num_bytes / sectorsize) * sectorsize;
-	uuid_generate(super.fsid);
+	memcpy(super.fsid, fsid, BTRFS_FSID_SIZE);
 	uuid_generate(super.dev_item.uuid);
 	uuid_generate(chunk_tree_uuid);
 
diff --git a/utils.h b/utils.h
index 3a0368b..c201a14 100644
--- a/utils.h
+++ b/utils.h
@@ -22,8 +22,8 @@ 
 #define BTRFS_MKFS_SYSTEM_GROUP_SIZE (4 * 1024 * 1024)
 
 int make_btrfs(int fd, const char *device, const char *label,
-	       u64 blocks[6], u64 num_bytes, u32 nodesize,
-	       u32 leafsize, u32 sectorsize, u32 stripesize);
+	       u8 fsid[BTRFS_FSID_SIZE], u64 blocks[6], u64 num_bytes,
+	       u32 nodesize, u32 leafsize, u32 sectorsize, u32 stripesize);
 int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root, u64 objectid);
 int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,