On Fri, Mar 30, 2018 at 12:24:15PM +0300, Amir Goldstein wrote:
> On Thu, Mar 29, 2018 at 10:38 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> > If an inode has been copied up metadata only, then we need to query the
> > number of blocks from lower and fill up the stat->st_blocks.
> >
> > We need to be careful about races where we are doing stat on one cpu and
> > data copy up is taking place on other cpu. We want to return
> > stat->st_blocks either from lower or stable upper and not something in
> > between. Hence, ovl_has_upperdata() is called first to figure out whether
> > block reporting will take place from lower or upper.
> >
> > Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> > Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> > ---
> > fs/overlayfs/inode.c | 17 ++++++++++++++++-
> > fs/overlayfs/overlayfs.h | 1 +
> > fs/overlayfs/util.c | 16 ++++++++++++++++
> > 3 files changed, 33 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> > index e1dbfed0c449..cd03f3e642fd 100644
> > --- a/fs/overlayfs/inode.c
> > +++ b/fs/overlayfs/inode.c
> > @@ -76,6 +76,9 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
> > bool is_dir = S_ISDIR(dentry->d_inode->i_mode);
> > bool samefs = ovl_same_sb(dentry->d_sb);
> > int err;
> > + bool metacopy = false;
> > +
> > + metacopy = ovl_is_metacopy_dentry(dentry);
> >
> > type = ovl_path_real(dentry, &realpath);
> > old_cred = ovl_override_creds(dentry->d_sb);
> > @@ -93,7 +96,8 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
> > if (!is_dir || samefs) {
> > if (OVL_TYPE_ORIGIN(type)) {
> > struct kstat lowerstat;
> > - u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0);
> > + u32 lowermask = STATX_INO | STATX_BLOCKS |
> > + (!is_dir ? STATX_NLINK : 0);
>
> Leftover.
>
> But I think you could do with one vfs_getattr():
>
> if (!is_dir || samefs) {
> u32 lowermask = metacopy ? STATX_BLOCKS : 0;
> if (OVL_TYPE_ORIGIN(type))
> lowermask |= STATX_INO | (!is_dir ? STATX_NLINK : 0);
> if (lowermask) {
> ovl_path_lower(dentry, &realpath);
> err = vfs_getattr(&realpath, &lowerstat,
We now support mid layer metacopy dentries. So we will need to do
vfs_getattr() on lowest data dentry for data blocks. While rest of
the info (inode number and nlink) comes from top most lower dentry.
So I don't think we can get rid of extra vfs_getattr()?
Vivek
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