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SubjectRE: [PATCH] f2fs: do not trim preallocated blocks when truncating after i_size
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> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, June 09, 2015 2:07 AM
> To: Chao Yu
> Cc: linux-f2fs-devel@lists.sourceforge.net; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] f2fs: do not trim preallocated blocks when truncating after i_size
>
> On Fri, Jun 05, 2015 at 06:34:02PM +0800, Chao Yu wrote:
> > When we perform generic/092 in xfstests, output is like below:
> >
> > XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > 0: [0..10239]: data
> > 0: [0..10239]: data
> > -1: [10240..20479]: unwritten
> > +1: [10240..14335]: unwritten
> >
> > This is because with this testcase, we redefine the regulation for
> > truncate in perallocated space past i_size as below:
> >
> > "There was some confused about what the fs was supposed to do when you
> > truncate at i_size with preallocated space past i_size. We decided on the
> > following things.
> >
> > 1) truncate(i_size) will trim all blocks past i_size.
> > 2) truncate(x) where x > i_size will not trim all blocks past i_size.
> > "
> >
> > This method is used in xfs, and then ext4/btrfs will follow the rule.
> >
> > This patch fixes to follow the new rule for f2fs.
> >
> > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > ---
> > fs/f2fs/file.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 4d42d66..85f97af 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -651,16 +651,16 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
> > f2fs_get_encryption_info(inode))
> > return -EACCES;
> >
> > - if (attr->ia_size != i_size_read(inode)) {
> > + if (attr->ia_size <= i_size_read(inode)) {
> > truncate_setsize(inode, attr->ia_size);
> > f2fs_truncate(inode);
> > f2fs_balance_fs(F2FS_I_SB(inode));
> > } else {
> > /*
> > - * giving a chance to truncate blocks past EOF which
> > - * are fallocated with FALLOC_FL_KEEP_SIZE.
> > + * do not trim all blocks after i_size if target size is
> > + * larger than i_size.
> > */
> > - f2fs_truncate(inode);
> > + truncate_setsize(inode, attr->ia_size);
>
> So, we can do:
> truncate_setsize();
>
> if (attr->ia_size <= i_size_read(inode)) {
> f2fs_truncate(inode);
> f2fs_balance_fs();
> }
>
> Right?

Yes, let me fix and resend the patch.

Thanks,
>
> > }
> > }
> >
> > --
> > 2.4.2



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