Re: [PATCH 3/3] f2fs: support clone_file_range

2 messages, 2 authors, 2016-07-19 · open the first message on its own page

Re: [PATCH 3/3] f2fs: support clone_file_range

From: Christoph Hellwig <hch@infradead.org>
Date: 2016-07-19 03:47:36

On Sat, Jul 16, 2016 at 11:24:27PM -0700, Jaegeuk Kim wrote:
This patch implements clone_file_range in f2fs.
[...]
quoted hunk
+int f2fs_clone_file_range(struct file *file_in, loff_t pos_in,
+		struct file *file_out, loff_t pos_out, u64 len)
+{
+	return f2fs_clone_files(file_in, pos_in, file_out, pos_out, len);
+}
+
Falling back from copy to clone should be done in the VFS.  I look into
implementing the fallback, and the code is trivial, but we don't seem
to have any useful coverage for copy_file_range yet, so I didn't dare
to add it yet.  How did you test copy and clone in f2fs?  And how did
you handle the difference in corner cases (e.g. the lacking 0 special
case in copy)?

------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are 
consuming the most bandwidth. Provides multi-vendor support for NetFlow, 
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev

Re: [PATCH 3/3] f2fs: support clone_file_range

From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: 2016-07-19 04:48:24

On Mon, Jul 18, 2016 at 08:47:36PM -0700, Christoph Hellwig wrote:
On Sat, Jul 16, 2016 at 11:24:27PM -0700, Jaegeuk Kim wrote:
quoted
This patch implements clone_file_range in f2fs.
[...]
quoted
+int f2fs_clone_file_range(struct file *file_in, loff_t pos_in,
+		struct file *file_out, loff_t pos_out, u64 len)
+{
+	return f2fs_clone_files(file_in, pos_in, file_out, pos_out, len);
+}
+
Falling back from copy to clone should be done in the VFS.  I look into
implementing the fallback, and the code is trivial, but we don't seem
to have any useful coverage for copy_file_range yet, so I didn't dare
to add it yet.  How did you test copy and clone in f2fs?  And how did
you handle the difference in corner cases (e.g. the lacking 0 special
case in copy)?
Frankly speaking, I confused the behaviors without being aware of corner cases.
And thus, I dropped the patches already. Instead, I realized that what I did
was moving a range of blocks from one file to another file. So, I've been
testing a new ioctl, F2FS_IOC_MOVE_RANGE.
In terms of coverage, I just did some unit tests only.

Thanks,

------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are 
consuming the most bandwidth. Provides multi-vendor support for NetFlow, 
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
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