On Wed 10-04-13 21:57:37, Dmitry Monakhov wrote: > On Thu, 21 Mar 2013 16:26:56 +0400, Dmitry Monakhov <dmonakhov@xxxxxxxxxx> wrote: > Ping... Please take a look at this fix. Actually, there are much more issues in this area. Fernando fixed most of them in his patch set (last posting is here http://www.spinics.net/lists/linux-fsdevel/msg61266.html I think) but it never got merged... Honza > > Commit: 18e9e5104fcd breaks connection between freeze_bdev()/thaw_bdev() and > > freeze_super()/thaw_super() > > In other workds: > > freeze_bdev()/thaw_bdev() may be called multiple times, but > > freeze_super()/thaw_super() only once (will resunt -EBUSY on second call) > > > > BUT user is still allowed to mix both interfaces: > > > > freeze_bdev () call it first time > > ->bdev->bd_fsfreeze_count++ > > ->freeze_super() > > return 0 > > freeze_super() second time > > ->bdev->bd_fsfreeze_count++ > > return 0 > > > > One can call ioctl_fsthaw( #xfs_freeze -u $MNT) > > ioctl_fsthaw > > ->thaw_super() -> fs is unfrozen now > > return 0 > > > > This leave bdev in broken state because: > > bd_fsfreeze_count > 0 but superblock is not frozen. > > Visiable effect: > > 0) Any freeze_bdev() will not call freeze_super() because > > (bdev->bd_fsfreeze_count > 0) > > 1) thaw_bdev() will fail because thaw_super() will return EINVAL (filesystem > > is not frozen) and bdev->bd_fsfreeze_count will not being decremented. > > 2) filesystem may not being mounted because mount_bdev will fail > > because (bdev->bd_fsfreeze_count > 0) > > > > #TEST_CASE: > > # Use xfstests 068'th test > > (while true ;do dmsetup suspend $SCRATCH_DEV ;dmsetup resume $SCRATCH_DEV;done)& > > pid=$! > > ./check 068 068 068 068 068 > > kill $pid > > wait $pid > > > > In order to fix that let's always use {freeze,thaw}_bdev() functions if > > super block has bdev, and directly call {freeze,thaw)_super() otherwise. > > > > Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx> > > --- > > fs/ioctl.c | 16 +++++++++++++--- > > 1 files changed, 13 insertions(+), 3 deletions(-) > > > > diff --git a/fs/ioctl.c b/fs/ioctl.c > > index 3bdad6d..ea47ccc 100644 > > --- a/fs/ioctl.c > > +++ b/fs/ioctl.c > > @@ -513,6 +513,7 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp, > > static int ioctl_fsfreeze(struct file *filp) > > { > > struct super_block *sb = filp->f_path.dentry->d_inode->i_sb; > > + int ret = 0; > > > > if (!capable(CAP_SYS_ADMIN)) > > return -EPERM; > > @@ -521,8 +522,15 @@ static int ioctl_fsfreeze(struct file *filp) > > if (sb->s_op->freeze_fs == NULL) > > return -EOPNOTSUPP; > > > > - /* Freeze */ > > - return freeze_super(sb); > > + if (sb->s_bdev) { > > + struct super_block *fsb; > > + fsb = freeze_bdev(sb->s_bdev); > > + if (IS_ERR(fsb)) > > + ret = PTR_ERR(fsb); > > + } else { > > + ret = freeze_super(sb); > > + } > > + return ret; > > } > > > > static int ioctl_fsthaw(struct file *filp) > > @@ -532,7 +540,9 @@ static int ioctl_fsthaw(struct file *filp) > > if (!capable(CAP_SYS_ADMIN)) > > return -EPERM; > > > > - /* Thaw */ > > + if (sb->s_bdev) > > + return thaw_bdev(sb->s_bdev, sb); > > + > > return thaw_super(sb); > > } > > > > -- > > 1.7.1 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
