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authorZach Brown <zab@redhat.com>2015-11-10 16:53:30 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2015-12-01 14:00:53 -0500
commit29732938a6289a15e907da234d6692a2ead71855 (patch)
tree51b31c22095cac9bbe24278647e679b635e7ccec /include/uapi/asm-generic/unistd.h
parent31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8 (diff)
vfs: add copy_file_range syscall and vfs helper
Add a copy_file_range() system call for offloading copies between regular files. This gives an interface to underlying layers of the storage stack which can copy without reading and writing all the data. There are a few candidates that should support copy offloading in the nearer term: - btrfs shares extent references with its clone ioctl - NFS has patches to add a COPY command which copies on the server - SCSI has a family of XCOPY commands which copy in the device This system call avoids the complexity of also accelerating the creation of the destination file by operating on an existing destination file descriptor, not a path. Currently the high level vfs entry point limits copy offloading to files on the same mount and super (and not in the same file). This can be relaxed if we get implementations which can copy between file systems safely. Signed-off-by: Zach Brown <zab@redhat.com> [Anna Schumaker: Change -EINVAL to -EBADF during file verification, Change flags parameter from int to unsigned int, Add function to include/linux/syscalls.h, Check copy len after file open mode, Don't forbid ranges inside the same file, Use rw_verify_area() to veriy ranges, Use file_out rather than file_in, Add COPY_FR_REFLINK flag] Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/uapi/asm-generic/unistd.h')
-rw-r--r--include/uapi/asm-generic/unistd.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 1324b0292ec2..2622b33fb2ec 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -715,9 +715,11 @@ __SYSCALL(__NR_userfaultfd, sys_userfaultfd)
__SYSCALL(__NR_membarrier, sys_membarrier)
#define __NR_mlock2 284
__SYSCALL(__NR_mlock2, sys_mlock2)
+#define __NR_copy_file_range 285
+__SYSCALL(__NR_copy_file_range, sys_copy_file_range)
#undef __NR_syscalls
-#define __NR_syscalls 285
+#define __NR_syscalls 286
/*
* All syscalls below here should go away really,

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