On Fri, Sep 23, 2016 at 09:52:42PM +0300, Amir Goldstein wrote: > 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. You could change XFS_RANDOM_AG_RESV_CRITICAL to a non-1 value to make it fail randomly (instead of all the time) and reflink a sparse file with a large number of extents. This... #define XFS_RANDOM_AG_RESV_CRITICAL 2 ...would make it fail half the time. --D > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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
