Messages in this thread | | | Date | Thu, 3 May 2018 17:02:17 +0200 | From | Jan Kara <> | Subject | Re: [PATCH 3/3] fs: fix corner case race on freeze_bdev() when sb disappears |
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On Fri 20-04-18 16:59:04, Luis R. Rodriguez wrote: > freeze_bdev() will bail but leave the bd_fsfreeze_count incremented > if the get_active_super() does not find the superblock on our > super_blocks list to match. > > This issue has been present since v2.6.29 during the introduction of the > ioctl_fsfreeze() and ioctl_fsthaw() via commit fcccf502540e3 ("filesystem > freeze: implement generic freeze feature"). > > I am not aware of any existing races which have triggered this > situation, however, if it does trigger it could mean leaving a > superblock with bd_fsfreeze_count always positive. > > Fixes: fcccf502540e3 ("filesystem freeze: implement generic freeze feature") > Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> --- > fs/block_dev.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index b54966679833..7a532aa58c07 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -507,8 +507,10 @@ struct super_block *freeze_bdev(struct block_device *bdev) > } > > sb = get_active_super(bdev); > - if (!sb) > + if (!sb) { > + bdev->bd_fsfreeze_count--; > goto out; > + } > if (sb->s_op->freeze_super) > error = sb->s_op->freeze_super(sb); > else > -- > 2.16.3 > -- Jan Kara <jack@suse.com> SUSE Labs, CR
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