On Mon, Oct 2, 2017 at 4:40 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> If it makes sense to copy up only metadata during copy up, do it. This
> is done for regular files which are not opened for WRITE and have origin
> being saved.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> ---
> fs/overlayfs/copy_up.c | 27 +++++++++++++++++++--------
> 1 file changed, 19 insertions(+), 8 deletions(-)
>
> diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
> index cdc4d79a1249..b2d9ed81e9ff 100644
> --- a/fs/overlayfs/copy_up.c
> +++ b/fs/overlayfs/copy_up.c
> @@ -306,11 +306,8 @@ static int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
> return PTR_ERR(fh);
> }
>
> - /*
> - * Do not fail when upper doesn't support xattrs.
> - */
> err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh,
> - fh ? fh->len : 0, 0);
> + fh ? fh->len : 0, -EOPNOTSUPP);
> kfree(fh);
>
> return err;
> @@ -328,6 +325,7 @@ struct ovl_copy_up_ctx {
> struct dentry *workdir;
> bool tmpfile;
> bool origin;
> + bool metadata_only;
> };
>
> static int ovl_link_up(struct ovl_copy_up_ctx *c)
> @@ -464,11 +462,15 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
> */
> if (c->origin) {
> err = ovl_set_origin(c->dentry, c->lowerpath.dentry, temp);
> - if (err)
> - return err;
> + if (err) {
> + if (err != -EOPNOTSUPP)
> + return err;
> + /* Upper does not support xattr. Copy up data as well */
> + c->metadata_only = false;
> + }
> }
>
> - if (S_ISREG(c->stat.mode)) {
> + if (S_ISREG(c->stat.mode) && !c->metadata_only) {
> struct path upperpath;
>
I would set the meta inode size here. see:
https://github.com/amir73il/linux/commits/ovl-rocopyup
> ovl_path_upper(c->dentry, &upperpath);
> @@ -596,6 +598,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
> .dentry = dentry,
> .workdir = ovl_workdir(dentry),
> .origin = true,
> + .metadata_only = true,
> };
>
> if (WARN_ON(!ctx.workdir))
> @@ -616,9 +619,17 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
> if (err)
> return err;
>
> + if (!S_ISREG(ctx.stat.mode))
> + ctx.metadata_only = false;
> +
> /* maybe truncate regular file. this has no effect on dirs */
> - if (flags & O_TRUNC)
> + if (flags & O_TRUNC) {
> ctx.stat.size = 0;
> + ctx.metadata_only = false;
> + }
> +
> + if (flags & (OPEN_FMODE(flags) & FMODE_WRITE))
> + ctx.metadata_only = false;
>
> if (S_ISLNK(ctx.stat.mode)) {
> ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done);
> --
> 2.13.5
>
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