> Sent: Thursday, March 15, 2018 at 4:25 PM
> From: "Ilya Dryomov" <idryomov@xxxxxxxxx>
> To: "Chengguang Xu" <cgxu519@xxxxxxx>
> Cc: "Yan, Zheng" <zyan@xxxxxxxxxx>, "Ceph Development" <ceph-devel@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH] ceph: surround debugfs related code with CONFIG_DEBUG_FS
>
> On Thu, Mar 15, 2018 at 8:12 AM, Chengguang Xu <cgxu519@xxxxxxx> wrote:
> > ceph_dentry_info lru is only for debug purpose now, so surround
> > related functions with CONFIG_DEBUG_FS and move to begin of the
> > file for deleting extern statement in header file.
> >
> > Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
> > ---
> > fs/ceph/dir.c | 105 ++++++++++++++++++++++++++++++++------------------------
> > fs/ceph/super.h | 2 --
> > 2 files changed, 61 insertions(+), 46 deletions(-)
> >
> > diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> > index 5c5ae93..867d6dc 100644
> > --- a/fs/ceph/dir.c
> > +++ b/fs/ceph/dir.c
> > @@ -30,6 +30,67 @@
> >
> > const struct dentry_operations ceph_dentry_ops;
> >
> > +#ifdef CONFIG_DEBUG_FS
> > +/*
> > + * We maintain a private dentry LRU.
> > + *
> > + * FIXME: this needs to be changed to a per-mds lru to be useful.
> > + */
> > +static void ceph_dentry_lru_add(struct dentry *dn)
> > +{
> > + struct ceph_dentry_info *di = ceph_dentry(dn);
> > + struct ceph_mds_client *mdsc;
> > +
> > + dout("dentry_lru_add %p %p '%pd'\n", di, dn, dn);
> > + mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
> > + spin_lock(&mdsc->dentry_lru_lock);
> > + list_add_tail(&di->lru, &mdsc->dentry_lru);
> > + mdsc->num_dentry++;
> > + spin_unlock(&mdsc->dentry_lru_lock);
> > +}
> > +
> > +void ceph_dentry_lru_touch(struct dentry *dn)
> > +{
> > + struct ceph_dentry_info *di = ceph_dentry(dn);
> > + struct ceph_mds_client *mdsc;
> > +
> > + dout("dentry_lru_touch %p %p '%pd' (offset %lld)\n", di, dn, dn,
> > + di->offset);
> > + mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
> > + spin_lock(&mdsc->dentry_lru_lock);
> > + list_move_tail(&di->lru, &mdsc->dentry_lru);
> > + spin_unlock(&mdsc->dentry_lru_lock);
> > +}
> > +
> > +static void ceph_dentry_lru_del(struct dentry *dn)
> > +{
> > + struct ceph_dentry_info *di = ceph_dentry(dn);
> > + struct ceph_mds_client *mdsc;
> > +
> > + dout("dentry_lru_del %p %p '%pd'\n", di, dn, dn);
> > + mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
> > + spin_lock(&mdsc->dentry_lru_lock);
> > + list_del_init(&di->lru);
> > + mdsc->num_dentry--;
> > + spin_unlock(&mdsc->dentry_lru_lock);
> > +}
> > +
> > +#else
> > +
> > +static void ceph_dentry_lru_add(struct dentry *dn)
> > +{
> > +}
> > +
> > +void ceph_dentry_lru_touch(struct dentry *dn)
> > +{
> > +}
> > +
> > +static void ceph_dentry_lru_del(struct dentry *dn)
> > +{
> > +}
> > +
> > +#endif /* CONFIG_DEBUG_FS */
> > +
> > /*
> > * Initialize ceph dentry state.
> > */
> > @@ -1418,50 +1479,6 @@ static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
> > }
> >
> > /*
> > - * We maintain a private dentry LRU.
> > - *
> > - * FIXME: this needs to be changed to a per-mds lru to be useful.
> > - */
> > -void ceph_dentry_lru_add(struct dentry *dn)
> > -{
> > - struct ceph_dentry_info *di = ceph_dentry(dn);
> > - struct ceph_mds_client *mdsc;
> > -
> > - dout("dentry_lru_add %p %p '%pd'\n", di, dn, dn);
> > - mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
> > - spin_lock(&mdsc->dentry_lru_lock);
> > - list_add_tail(&di->lru, &mdsc->dentry_lru);
> > - mdsc->num_dentry++;
> > - spin_unlock(&mdsc->dentry_lru_lock);
> > -}
> > -
> > -void ceph_dentry_lru_touch(struct dentry *dn)
> > -{
> > - struct ceph_dentry_info *di = ceph_dentry(dn);
> > - struct ceph_mds_client *mdsc;
> > -
> > - dout("dentry_lru_touch %p %p '%pd' (offset %lld)\n", di, dn, dn,
> > - di->offset);
> > - mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
> > - spin_lock(&mdsc->dentry_lru_lock);
> > - list_move_tail(&di->lru, &mdsc->dentry_lru);
> > - spin_unlock(&mdsc->dentry_lru_lock);
> > -}
> > -
> > -void ceph_dentry_lru_del(struct dentry *dn)
> > -{
> > - struct ceph_dentry_info *di = ceph_dentry(dn);
> > - struct ceph_mds_client *mdsc;
> > -
> > - dout("dentry_lru_del %p %p '%pd'\n", di, dn, dn);
> > - mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
> > - spin_lock(&mdsc->dentry_lru_lock);
> > - list_del_init(&di->lru);
> > - mdsc->num_dentry--;
> > - spin_unlock(&mdsc->dentry_lru_lock);
> > -}
> > -
> > -/*
> > * Return name hash for a given dentry. This is dependent on
> > * the parent directory's hash function.
> > */
> > diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> > index 04198ae..7557dde 100644
> > --- a/fs/ceph/super.h
> > +++ b/fs/ceph/super.h
> > @@ -1058,9 +1058,7 @@ extern int ceph_handle_snapdir(struct ceph_mds_request *req,
> > extern struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
> > struct dentry *dentry, int err);
> >
> > -extern void ceph_dentry_lru_add(struct dentry *dn);
> > extern void ceph_dentry_lru_touch(struct dentry *dn);
> > -extern void ceph_dentry_lru_del(struct dentry *dn);
> > extern void ceph_invalidate_dentry_lease(struct dentry *dentry);
> > extern unsigned int ceph_dentry_hash(struct inode *dir, struct dentry *dn);
> > extern void ceph_readdir_cache_release(struct ceph_readdir_cache_control *ctl);
>
> Hi Chengguang,
>
> AFAICT it has always been used exclusively for debugging.
>
> We don't want to get in the way of people wanting to build their
> kernels without debugfs, so some !CONFIG_DEBUG_FS stubs are necessary,
> but as long as it compiles without debugfs, let's not add new ones.
Hi Ilya,
Got it, Thanks.
Chengguang.
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