On Jul 8, 2014, at 2:41 PM, Azat Khuzhin <a3at.mail@xxxxxxxxx> wrote: > 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> It may be that the reverse problem also exists - if the UUID is changed on the filesystem, it probably is not updated in the journal "users" list? I'm not sure either way, but it is worthwhile to check. 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 811cb4d..898a1b3 100644 > --- a/misc/tune2fs.c > +++ b/misc/tune2fs.c > @@ -180,6 +180,38 @@ static __u32 clear_ok_features[3] = { > EXT4_FEATURE_RO_COMPAT_METADATA_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 > */ > @@ -223,29 +255,15 @@ 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++) { > @@ -2695,6 +2713,7 @@ retry_open: > if (U_flag) { > int set_csum = 0; > dgrp_t i; > + char buf[SUPERBLOCK_SIZE]; > > if (ext2fs_has_group_desc_csum(fs)) { > /* > @@ -2740,6 +2759,25 @@ 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 (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, > EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) > -- > 2.0.0 > > -- > 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 Cheers, Andreas
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