Re: [PATCH 2/2] ext4: Fix mmap data corruption when blocksize < pagesize

Jan Kara
2014-09-24T08:57:37Z

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On Wed 24-09-14 10:45:19, Jan Kara wrote:
> On Tue 23-09-14 17:03:23, Jan Kara wrote:
> > Use block_create_hole() when hole is being created in a file so that
> > ->page_mkwrite() will get called for the partial tail page if it is
> > mmaped (see the first patch in the series for details).
> Just out of curiosity I did a change similar to this one for ext4 to XFS
> and indeed it fixed generic/030 test failures for XFS with blocksize 1k.
Just for reference attached the patch I was testing - I can resend with
proper changelog etc. if people are fine with this approach.

Honza

> > Signed-off-by: Jan Kara <jack@suse.cz>
> > ---
> > fs/ext4/inode.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > index 3aa26e9117c4..fdcb007c2c9e 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -4536,8 +4536,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
> > ext4_orphan_del(NULL, inode);
> > goto err_out;
> > }
> > - } else
> > + } else {
> > + loff_t old_size = inode->i_size;
> > +
> > i_size_write(inode, attr->ia_size);
> > + block_create_hole(inode, old_size, inode->i_size);
> > + }
> >
> > /*
> > * Blocks are going to be removed from the inode. Wait
> > --
> > 1.8.1.4
> >
> --
> Jan Kara <jack@suse.cz>
> SUSE Labs, CR
> --
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--
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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>From ceedc36b1c99c25ebb55c88f6ab059347b52f4ec Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Wed, 24 Sep 2014 10:18:25 +0200
Subject: [PATCH] xfs: Fix mmap data corruption

Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/xfs/xfs_iops.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 72129493e9d3..19ce64bfb4f7 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -848,6 +848,8 @@ xfs_setattr_size(
if (error)
return error;
truncate_setsize(inode, newsize);
+ if (oldsize < newsize)
+ block_create_hole(inode, oldsize, newsize);

tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_SIZE);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
--
1.8.1.4

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