On Mon, Sep 12, 2016 at 06:06:42PM +0300, Amir Goldstein wrote: > copy_file_range syscall returns -EXDEV if src and dest > file are not on the same file system. > The vfs_copy_file_range() helper, however, knows how to copy > across file systems with do_splice_direct(). > > Move the enforcement of same file system from the vfs helper > to the syscall code. > > A following patch is going to use the vfs_copy_file_range() > helper in overlayfs to copy up between lower and upper > not on the same file system. > > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > fs/read_write.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/fs/read_write.c b/fs/read_write.c > index 9dc6e52..c4675c6 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -1502,10 +1502,6 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > (file_out->f_flags & O_APPEND)) > return -EBADF; > > - /* this could be relaxed once a method supports cross-fs copies */ > - if (inode_in->i_sb != inode_out->i_sb) > - return -EXDEV; > - > if (len == 0) > return 0; > > @@ -1514,7 +1510,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > return ret; > > ret = -EOPNOTSUPP; > - if (file_out->f_op->copy_file_range) > + if (inode_in->i_sb == inode_out->i_sb && > + file_out->f_op->copy_file_range) > ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, > pos_out, len, flags); Indenting is wrong, and you dropped an important comment. i.e copy_file_range() still doesn't support cross fs copies..... > if (ret == -EOPNOTSUPP) > @@ -1569,6 +1566,14 @@ SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in, > pos_out = f_out.file->f_pos; > } > > + /* > + * FIXME: should copy_file_range syscall enforce that src and > + * dest files are on the same mount point or only on the same > + * file system? none of the above? > + */ > + if (file_inode(f_in.file)->i_sb != file_inode(f_out.file)->i_sb) > + return -EXDEV; For the purposes of this patch, it should simply do what it already does. If there's a API semantic change that needs to be made, then get that sorted out now rather than adding a "fixme" comment that will simply be ignored.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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
