|| ||Joel Becker <firstname.lastname@example.org> |
|| ||email@example.com |
|| ||[RFC] The reflink(2) system call. |
|| ||Sat, 2 May 2009 23:15:00 -0700|
|| ||firstname.lastname@example.org, email@example.com,
|| ||Article, Thread
I described the reflink operation at the Linux Storage &
Filesystems Workshop last month. Originally implemented as an
ocfs2-specific ioctl, the consensus was that it should be a syscall from
the get-go. Here's some first-cut patches.
For people who have not seen reflink, either at LSF or on the
ocfs2 wiki, the first patch contains
Documentation/filesystems/reflink.txt to describe the call. The
short-short version is that reflink creates a reference-counted link.
This is a new file that shares the data extents of a source file in a
The second patch adds iops->reflink() and vfs_reflink(). People
interested in LSM interaction, please look at my comments in the patch
header and the implementation of vfs_link(). I think it needs
The last patch defines sys_reflink() and sys_reflinkat(). It
also hooks them up for x86_32. The final version of this patch will
obviously include the other architectures.
The patches are also available in my git tree:
The current ioctl-based implementation for ocfs2 is available in Tao's
git tree at:
It will be reset atop the system call very soon.
Please send any comments along.
Documentation/filesystems/reflink.txt | 129 ++++++++++++++++++++++++++++++++++
Documentation/filesystems/vfs.txt | 4 +
arch/x86/include/asm/unistd_32.h | 1
arch/x86/kernel/syscall_table_32.S | 1
fs/namei.c | 96 +++++++++++++++++++++++++
include/linux/fs.h | 2
6 files changed, 233 insertions(+)
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