| Message ID | 1473692803-11964-4-git-send-email-amir73il@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@gmail.com> > --- > 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.
On Tue, Sep 13, 2016 at 3:08 AM, Dave Chinner <david@fromorbit.com> wrote: > 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@gmail.com> >> --- >> 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..... OK. moved the comment down this this same i_sb test > >> 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.... How about: /* * vfs_copy_file_range() can do cross-fs copy, but we want to * fulfill the guaranty to userland that copy_file_range syscall * does not allow cross-fs copy */ Cheers, Amir. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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); 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; + ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len, flags); if (ret > 0) {
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@gmail.com> --- fs/read_write.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)