Copy system calls came up during Plumbers a while ago, mostly because several filesystems (including NFS and XFS) are currently working on copy acceleration implementations. We haven't heard from Zach Brown in a while, so I volunteered to push his patches upstream so individual filesystems don't need to keep writing their own ioctls. The question has come up about how vfs_copy_file_range() responds to signals, and I don't have a good answer. The pagecache copy option uses splice, which (as far as I can tell) doesn't get interrupted. Please let me know if I'm missing something or completely misunderstanding the question! Changes in v3: - Update against the most recent Linus kernel - Flags parameter should be an unsigned int - Add COPY_FR_DEDUPE flag for Darrick - Make each flag exclusive - Update man page - Added "Reiewed-by" tags I tested the COPY_FR_COPY flag by using /dev/urandom to generate files of varying sizes and copying them. I compared the output from `time` against that of `cp` to see if there is any noticable difference. Values in the tables below are averages across multiple trials. /usr/bin/cp | 512 | 1024 | 1536 | 2048 | 2560 | 3072 | 5120 -------------|--------|--------|--------|--------|--------|--------|-------- user | 0.00s | 0.00s | 0.01s | 0.01s | 0.01s | 0.01s | 0.02s system | 0.92s | 0.59s | 0.88s | 1.18s | 1.48s | 1.78s | 2.98s cpu | 43% | 18% | 17% | 18% | 18% | 18% | 17% total | 2.116 | 3.200 | 4.950 | 6.541 | 8.105 | 9.811 | 17.211 VFS Copy | 512 | 1024 | 1536 | 2048 | 2560 | 3072 | 5120 -------------|--------|--------|--------|--------|--------|--------|-------- user | 0.00s | 0.00s | 0.00s | 0.00s | 0.00s | 0.00s | 0.00s system | 0.80s | 0.56s | 0.84s | 1.10s | 1.39s | 1.67s | 2.81s cpu | 41% | 18% | 19% | 17% | 17% | 17% | 17% total | 1.922 | 2.990 | 4.448 | 6.292 | 7.855 | 9.480 | 15.944 Questions? Comments? Thoughts? Anna Anna Schumaker (6): vfs: Copy should check len after file open mode vfs: Copy shouldn't forbid ranges inside the same file vfs: Copy should use file_out rather than file_in vfs: Remove copy_file_range mountpoint checks vfs: copy_file_range() can do a pagecache copy with splice btrfs: btrfs_copy_file_range() only supports reflinks Zach Brown (3): vfs: add copy_file_range syscall and vfs helper x86: add sys_copy_file_range to syscall tables btrfs: add .copy_file_range file operation arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/btrfs/ctree.h | 3 + fs/btrfs/file.c | 1 + fs/btrfs/ioctl.c | 95 +++++++++++++--------- fs/read_write.c | 141 +++++++++++++++++++++++++++++++++ include/linux/copy.h | 6 ++ include/linux/fs.h | 3 + include/uapi/asm-generic/unistd.h | 2 + include/uapi/linux/Kbuild | 1 + include/uapi/linux/copy.h | 8 ++ kernel/sys_ni.c | 1 + 12 files changed, 224 insertions(+), 39 deletions(-) create mode 100644 include/linux/copy.h create mode 100644 include/uapi/linux/copy.h -- 2.5.3 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html