On Fri, Sep 23, 2016 at 7:13 PM, Darrick J. Wong <darrick.wong@xxxxxxxxxx> wrote: > On Fri, Sep 23, 2016 at 10:57:56AM +0300, Amir Goldstein wrote: >> On Wed, Sep 14, 2016 at 3:43 PM, Amir Goldstein <amir73il@xxxxxxxxx> 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 | 16 +++++++++++----- >> > 1 file changed, 11 insertions(+), 5 deletions(-) >> > >> > diff --git a/fs/read_write.c b/fs/read_write.c >> > index 9dc6e52..6975fe8 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 +1510,9 @@ 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) >> > + /* copy_file_range() method does not support cross-fs copies */ >> > + 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 +1567,14 @@ SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in, >> > pos_out = f_out.file->f_pos; >> > } >> > >> > + /* >> > + * 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 >> > + */ >> > + if (file_inode(f_in.file)->i_sb != file_inode(f_out.file)->i_sb) >> > + return -EXDEV; >> >> Oops, that was supposed to be goto out; >> Anyway, I am holding back on the vfs_copy_file_range() patches sub set >> until I have a reliable test on xfs to fall back from clone to copy range > > Ok, attached are two rough patches -- one to add the error injection point > into the kernel, and a second one to add it to the xfs_io 'inject' command. > Note that you'll have to format the XFS filesystem with rmapbt=1 since we > can't otherwise avoid per-AG ENOSPC if rmap is enabled. > > The relevant xfstests commands are: > > _require_xfs_io_error_injection "ag_resv_critical" > _scratch_inject_error "ag_resv_critical" > > See the xfs/325 test for a rough framework. I'll work on cleaning up the > patches and trying to get them into 4.9. > Thanks, Darrick, but I'm not sure that's enough. does the framework allow to inject an error for a specific AG? otherwise, the code will not fall back from failing full reflink to partial copy partial reflink. -- 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
