I already fixed that in my recent patch: http://marc.info/?l=linux-ext4&m=140667665421773&w=2 Cheers, Andreas > On Jul 31, 2014, at 17:45, Azat Khuzhin <a3at.mail@xxxxxxxxx> wrote: > >> 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
