----- 原始邮件 ----- > 发件人: "Eric Sandeen" <sandeen@xxxxxxxxxxx> > 收件人: "Jianhong.Yin" <yin-jianhong@xxxxxxx>, linux-xfs@xxxxxxxxxxxxxxx > 抄送: jiyin@xxxxxxxxxx, "darrick wong" <darrick.wong@xxxxxxxxxx> > 发送时间: 星期六, 2019年 9 月 07日 上午 5:04:13 > 主题: Re: [PATCH v2] xfs_io: copy_range don't truncate dst_file, and add smart length > > On 9/6/19 12:02 PM, 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 > > > > and have confirmed that this change will not affect xfstests. > > > > Signed-off-by: Jianhong Yin <yin-jianhong@xxxxxxx> > > --- > > io/copy_file_range.c | 22 +++++----------------- > > man/man8/xfs_io.8 | 12 ++++++------ > > 2 files changed, 11 insertions(+), 23 deletions(-) > > > > diff --git a/io/copy_file_range.c b/io/copy_file_range.c > > index b7b9fd88..2bc8494e 100644 > > --- a/io/copy_file_range.c > > +++ b/io/copy_file_range.c > > @@ -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; > > I'd like to change these to src_off & dst_off, just to help keep track > of things. that's better, suggest apply same change to copy_file_range_cmd(): -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; } > > > size_t len = 0; > > + bool len_specified = false; > > int opt; > > int ret; > > int fd; > > @@ -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) { > > normal xfsprogs style is no space after the ! Good to know. > > > off64_t sz; > > > > sz = copy_src_filesize(fd); > > @@ -145,13 +138,8 @@ 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) > > + len = sz - src; > > Ok, so if source offset is past EOF, we keep len = 0. > > Looks like the kernel does that internally too, so no problem there. > > I'll make the cosmetic changes I mentioned above when I commit it, unless > you have any concerns about that. looks good to me. thanks Eric Darrick and Zorro. > > /* Shorten the copy to EOF */ > size_in = i_size_read(inode_in); > if (pos_in >= size_in) > count = 0; > > Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx> > > > } > > > > ret = copy_file_range_cmd(fd, &src, &dst, len); > > 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 > > >
