From: Eric Sandeen <sandeen@sandeen.net>
To: "Jianhong.Yin" <yin-jianhong@163.com>, linux-xfs@vger.kernel.org
Cc: jiyin@redhat.com, darrick.wong@oracle.com, sandeen@redhat.com
Subject: Re: [PATCH v3] xfs_io: copy_range don't truncate dst_file, and add smart length
Date: Tue, 24 Sep 2019 17:04:16 -0500 [thread overview]
Message-ID: <805e278f-c04c-c351-a629-2c5b0c5df7ce@sandeen.net> (raw)
In-Reply-To: <20190909072903.2749-1-yin-jianhong@163.com>
On 9/9/19 2:29 AM, Jianhong.Yin wrote:
> 1. copy_range should be a simple wrapper for copy_file_range(2)
> and nothing else. and there's already -t option for truncate.
> so here we remove the truncate action in copy_range.
> see: https://patchwork.kernel.org/comment/22863587/#1
>
> 2. improve the default length value generation:
> if -l option is omitted use the length that from src_offset to end
> (src_file's size - src_offset) instead.
> if src_offset is greater than file size, length is 0.
>
> 3. update manpage
>
> 4. rename var name from 'src, dst' to 'src_off, dst_off'
>
> and have confirmed that this change will not affect xfstests.
>
> Signed-off-by: Jianhong Yin <yin-jianhong@163.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
> ---
> io/copy_file_range.c | 40 ++++++++++++++--------------------------
> man/man8/xfs_io.8 | 12 ++++++------
> 2 files changed, 20 insertions(+), 32 deletions(-)
>
> diff --git a/io/copy_file_range.c b/io/copy_file_range.c
> index b7b9fd88..c2105115 100644
> --- a/io/copy_file_range.c
> +++ b/io/copy_file_range.c
> @@ -36,12 +36,12 @@ copy_range_help(void)
> * glibc buffered copy fallback.
> */
> static loff_t
> -copy_file_range_cmd(int fd, long long *src, long long *dst, size_t len)
> +copy_file_range_cmd(int fd, long long *src_off, long long *dst_off, size_t len)
> {
> loff_t ret;
>
> do {
> - ret = syscall(__NR_copy_file_range, fd, src, file->fd, dst,
> + ret = syscall(__NR_copy_file_range, fd, src_off, file->fd, dst_off,
> len, 0);
> if (ret == -1) {
> perror("copy_range");
> @@ -66,21 +66,13 @@ copy_src_filesize(int fd)
> return st.st_size;
> }
>
> -static int
> -copy_dst_truncate(void)
> -{
> - int ret = ftruncate(file->fd, 0);
> - if (ret < 0)
> - perror("ftruncate");
> - return ret;
> -}
> -
> static int
> copy_range_f(int argc, char **argv)
> {
> - long long src = 0;
> - long long dst = 0;
> + long long src_off = 0;
> + long long dst_off = 0;
> size_t len = 0;
> + bool len_specified = false;
> int opt;
> int ret;
> int fd;
> @@ -93,15 +85,15 @@ copy_range_f(int argc, char **argv)
> while ((opt = getopt(argc, argv, "s:d:l:f:")) != -1) {
> switch (opt) {
> case 's':
> - src = cvtnum(fsblocksize, fssectsize, optarg);
> - if (src < 0) {
> + src_off = cvtnum(fsblocksize, fssectsize, optarg);
> + if (src_off < 0) {
> printf(_("invalid source offset -- %s\n"), optarg);
> return 0;
> }
> break;
> case 'd':
> - dst = cvtnum(fsblocksize, fssectsize, optarg);
> - if (dst < 0) {
> + dst_off = cvtnum(fsblocksize, fssectsize, optarg);
> + if (dst_off < 0) {
> printf(_("invalid destination offset -- %s\n"), optarg);
> return 0;
> }
> @@ -112,6 +104,7 @@ copy_range_f(int argc, char **argv)
> printf(_("invalid length -- %s\n"), optarg);
> return 0;
> }
> + len_specified = true;
> break;
> case 'f':
> src_file_nr = atoi(argv[1]);
> @@ -137,7 +130,7 @@ copy_range_f(int argc, char **argv)
> fd = filetable[src_file_nr].fd;
> }
>
> - if (src == 0 && dst == 0 && len == 0) {
> + if (!len_specified) {
> off64_t sz;
>
> sz = copy_src_filesize(fd);
> @@ -145,16 +138,11 @@ copy_range_f(int argc, char **argv)
> ret = 1;
> goto out;
> }
> - len = sz;
> -
> - ret = copy_dst_truncate();
> - if (ret < 0) {
> - ret = 1;
> - goto out;
> - }
> + if (sz > src_off)
> + len = sz - src_off;
> }
>
> - ret = copy_file_range_cmd(fd, &src, &dst, len);
> + ret = copy_file_range_cmd(fd, &src_off, &dst_off, len);
> out:
> close(fd);
> return ret;
> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> index 6e064bdd..61c35c8e 100644
> --- a/man/man8/xfs_io.8
> +++ b/man/man8/xfs_io.8
> @@ -669,13 +669,13 @@ The source must be specified either by path
> or as another open file
> .RB ( \-f ).
> If
> -.I src_file
> -.IR src_offset ,
> -.IR dst_offset ,
> -and
> .I length
> -are omitted the contents of src_file will be copied to the beginning of the
> -open file, overwriting any data already there.
> +is not specified, this command copies data from
> +.I src_offset
> +to the end of
> +.BI src_file
> +into the dst_file at
> +.IR dst_offset .
> .RS 1.0i
> .PD 0
> .TP 0.4i
>
prev parent reply other threads:[~2019-09-24 22:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 7:29 [PATCH v3] xfs_io: copy_range don't truncate dst_file, and add smart length Jianhong.Yin
2019-09-24 22:04 ` Eric Sandeen [this message]
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