Using -U option you can change the UUID for fs, however it will not work for journal device, since it have a copy of this UUID inside jsb (i.e. journal super block). So copy UUID on change into that block. Here is the initial thread: http://comments.gmane.org/gmane.comp.file-systems.ext4/44532 You can reproduce this by executing following commands: $ fallocate -l100M /tmp/dev $ fallocate -l100M /tmp/journal $ sudo /sbin/losetup /dev/loop1 /tmp/dev $ sudo /sbin/losetup /dev/loop0 /tmp/journal $ mke2fs -O journal_dev /tmp/journal $ tune2fs -U da1f2ed0-60f6-aaaa-92fd-738701418523 /tmp/journal $ sudo mke2fs -t ext4 -J device=/dev/loop0 /dev/loop1 $ dumpe2fs -h /tmp/dev | fgrep UUID dumpe2fs 1.43-WIP (18-May-2014) Filesystem UUID: 8a776be9-12eb-411f-8e88-b873575ecfb6 Journal UUID: e3d02151-e776-4865-af25-aecb7291e8e5 $ sudo e2fsck /dev/vdc e2fsck 1.43-WIP (18-May-2014) External journal does not support this filesystem /dev/loop1: ********** WARNING: Filesystem still has errors ********** Reported-by: Chin Tzung Cheng <chintzung@xxxxxxxxx> Signed-off-by: Azat Khuzhin <a3at.mail@xxxxxxxxx> Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx> --- misc/tune2fs.c | 74 ++++++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 56 insertions(+), 18 deletions(-) diff --git a/misc/tune2fs.c b/misc/tune2fs.c index 1df655a..74e57ae 100644 --- a/misc/tune2fs.c +++ b/misc/tune2fs.c @@ -175,6 +175,38 @@ static __u32 clear_ok_features[3] = { EXT4_FEATURE_RO_COMPAT_GDT_CSUM }; +/** + * Try to get journal super block if any + */ +static int get_journal_sb(ext2_filsys jfs, char buf[SUPERBLOCK_SIZE]) +{ + int retval; + int start; + journal_superblock_t *jsb; + + if (!(jfs->super->s_feature_incompat & + EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) { + return EXT2_ET_UNSUPP_FEATURE; + } + + /* Get the journal superblock */ + if ((retval = io_channel_read_blk64(jfs->io, + ext2fs_journal_sb_start(jfs->blocksize), -SUPERBLOCK_SIZE, buf))) { + com_err(program_name, retval, "%s", + _("while reading journal superblock")); + return retval; + } + + jsb = (journal_superblock_t *) buf; + if ((jsb->s_header.h_magic != (unsigned)ntohl(JFS_MAGIC_NUMBER)) || + (jsb->s_header.h_blocktype != (unsigned)ntohl(JFS_SUPERBLOCK_V2))) { + fputs(_("Journal superblock not found!\n"), stderr); + return EXT2_ET_BAD_MAGIC; + } + + return 0; +} + /* * Remove an external journal from the filesystem */ @@ -218,29 +250,15 @@ static int remove_journal_device(ext2_filsys fs) _("while trying to open external journal")); goto no_valid_journal; } - if (!(jfs->super->s_feature_incompat & - EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) { - fprintf(stderr, _("%s is not a journal device.\n"), - journal_path); - goto no_valid_journal; - } - start = ext2fs_journal_sb_start(fs->blocksize); - /* Get the journal superblock */ - if ((retval = io_channel_read_blk64(jfs->io, start, - -SUPERBLOCK_SIZE, buf))) { - com_err(program_name, retval, "%s", - _("while reading journal superblock")); + if ((retval = get_journal_sb(jfs, buf))) { + if (retval == EXT2_ET_UNSUPP_FEATURE) + fprintf(stderr, _("%s is not a journal device.\n"), + journal_path); goto no_valid_journal; } jsb = (journal_superblock_t *) buf; - if ((jsb->s_header.h_magic != (unsigned)ntohl(JFS_MAGIC_NUMBER)) || - (jsb->s_header.h_blocktype != (unsigned)ntohl(JFS_SUPERBLOCK_V2))) { - fputs(_("Journal superblock not found!\n"), stderr); - goto no_valid_journal; - } - /* Find the filesystem UUID */ nr_users = ntohl(jsb->s_nr_users); for (i = 0; i < nr_users; i++) { @@ -2184,6 +2202,7 @@ retry_open: if (U_flag) { int set_csum = 0; dgrp_t i; + char buf[SUPERBLOCK_SIZE]; if (sb->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_GDT_CSUM) { @@ -2229,6 +2248,25 @@ retry_open: ext2fs_group_desc_csum_set(fs, i); fs->flags &= ~EXT2_FLAG_SUPER_ONLY; } + + /* If this is a journal dev, we need to copy UUID into jsb */ + if (!(rc = get_journal_sb(fs, buf))) { + journal_superblock_t *jsb; + + jsb = (journal_superblock_t *) buf; + fputs(_("Need to update journal superblock.\n"), stdout); + memcpy(jsb->s_uuid, sb->s_uuid, sizeof(sb->s_uuid)); + + /* Writeback the journal superblock */ + if ((rc = io_channel_write_blk64(fs->io, + ext2fs_journal_sb_start(fs->blocksize), + -SUPERBLOCK_SIZE, buf))) + goto closefs; + } else if (rc != EXT2_ET_UNSUPP_FEATURE) + goto closefs; + else + rc = 0; /** Reset rc to avoid ext2fs_mmp_stop() */ + ext2fs_mark_super_dirty(fs); } if (I_flag) { -- 2.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
