On Thu, Jul 31, 2014 at 10:16:44AM -0500, Eric Sandeen wrote: > On 7/28/14, 2:43 AM, Azat Khuzhin 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> > > 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); > > This is already committed (which is why Coverity whined about it), but: > removing this assignment causes an uninitialized use of "start" later > in this function: > > /* Write back the journal superblock */ > if ((retval = io_channel_write_blk64(jfs->io, start, > -SUPERBLOCK_SIZE, buf))) > > -Eric Hi Eric, Thanks for catching this. Patch in attachment must fix this issue. I maked with -Wall to catch more bugs like this. And there is one more note: expected ‘char *’ but argument is of type ‘__u8 *’ journal_user() I will send a patch later. >From 903f251e1ebce3d666a8b2af04b812d4f6751056 Mon Sep 17 00:00:00 2001 From: Azat Khuzhin <a3at.mail@xxxxxxxxx> Date: Thu, 31 Jul 2014 19:26:16 +0400 Subject: [PATCH] tune2fs: initialize start block in remove_journal_device() --- misc/tune2fs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/misc/tune2fs.c b/misc/tune2fs.c index 0c1feb1..044daaf 100644 --- a/misc/tune2fs.c +++ b/misc/tune2fs.c @@ -181,7 +181,6 @@ static __u32 clear_ok_features[3] = { 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 & @@ -286,6 +285,7 @@ static int remove_journal_device(ext2_filsys fs) jsb->s_nr_users = htonl(nr_users); /* Write back the journal superblock */ + start = ext2fs_journal_sb_start(jfs->blocksize); if ((retval = io_channel_write_blk64(jfs->io, start, -SUPERBLOCK_SIZE, buf))) { com_err(program_name, retval, -- 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
