[PATCH] f2fs: do not trim preallocated blocks when truncating after i_size

[PATCH] f2fs: do not trim preallocated blocks when truncating after i_size

[Chao Yu]

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);
 		}
 	}
 
-- 
2.4.2

Re: [PATCH] f2fs: do not trim preallocated blocks when truncating after i_size

[Jaegeuk Kim]

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?

>  		}
>  	}
>  
> -- 
> 2.4.2

Re: [PATCH] f2fs: do not trim preallocated blocks when truncating after i_size

[Chao Yu]

> -----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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