On Fri, 2019-02-01 at 22:22 +0800, Yan, Zheng wrote:
> introduce ceph_d_delete(), which checks if dentry has valid lease.
>
> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
> ---
> fs/ceph/dir.c | 132 +++++++++++++++++++++++++++++++++----------
> fs/ceph/inode.c | 2 +-
> fs/ceph/mds_client.c | 2 +-
> fs/ceph/super.h | 2 +-
> 4 files changed, 106 insertions(+), 32 deletions(-)
>
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 82928cea0209..bb5d765fcaae 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -1139,45 +1139,59 @@ void ceph_invalidate_dentry_lease(struct dentry *dentry)
> * Check if dentry lease is valid. If not, delete the lease. Try to
> * renew if the least is more than half up.
> */
> +static bool __dentry_lease_is_valid(struct ceph_dentry_info *di)
> +{
> + struct ceph_mds_session *session;
> +
> + if (!di->lease_gen)
> + return false;
> +
> + session = di->lease_session;
> + if (session) {
> + u32 gen;
> + unsigned long ttl;
> +
> + spin_lock(&session->s_gen_ttl_lock);
> + gen = session->s_cap_gen;
> + ttl = session->s_cap_ttl;
> + spin_unlock(&session->s_gen_ttl_lock);
> +
> + if (di->lease_gen == gen &&
> + time_before(jiffies, ttl) &&
> + time_before(jiffies, di->time))
> + return true;
> + }
> + di->lease_gen = 0;
> + return false;
> +}
> +
> static int dentry_lease_is_valid(struct dentry *dentry, unsigned int flags,
> struct inode *dir)
> {
> struct ceph_dentry_info *di;
> - struct ceph_mds_session *s;
> - int valid = 0;
> - u32 gen;
> - unsigned long ttl;
> struct ceph_mds_session *session = NULL;
> u32 seq = 0;
> + int valid = 0;
>
> spin_lock(&dentry->d_lock);
> di = ceph_dentry(dentry);
> - if (di && di->lease_session) {
> - s = di->lease_session;
> - spin_lock(&s->s_gen_ttl_lock);
> - gen = s->s_cap_gen;
> - ttl = s->s_cap_ttl;
> - spin_unlock(&s->s_gen_ttl_lock);
> + if (di && __dentry_lease_is_valid(di)) {
> + valid = 1;
>
> - if (di->lease_gen == gen &&
> - time_before(jiffies, di->time) &&
> - time_before(jiffies, ttl)) {
> - valid = 1;
> - if (di->lease_renew_after &&
> - time_after(jiffies, di->lease_renew_after)) {
> - /*
> - * We should renew. If we're in RCU walk mode
> - * though, we can't do that so just return
> - * -ECHILD.
> - */
> - if (flags & LOOKUP_RCU) {
> - valid = -ECHILD;
> - } else {
> - session = ceph_get_mds_session(s);
> - seq = di->lease_seq;
> - di->lease_renew_after = 0;
> - di->lease_renew_from = jiffies;
> - }
> + if (di->lease_renew_after &&
> + time_after(jiffies, di->lease_renew_after)) {
> + /*
> + * We should renew. If we're in RCU walk mode
> + * though, we can't do that so just return
> + * -ECHILD.
> + */
> + if (flags & LOOKUP_RCU) {
> + valid = -ECHILD;
> + } else {
> + session = ceph_get_mds_session(di->lease_session);
> + seq = di->lease_seq;
> + di->lease_renew_after = 0;
> + di->lease_renew_from = jiffies;
> }
> }
> }
> @@ -1192,6 +1206,40 @@ static int dentry_lease_is_valid(struct dentry *dentry, unsigned int flags,
> return valid;
> }
>
> +/*
> + * Called under dentry->d_lock.
> + */
> +static int __dir_lease_try_check(const struct dentry *dentry)
> +{
> + struct ceph_dentry_info *di = ceph_dentry(dentry);
> + struct inode *dir;
> + struct ceph_inode_info *ci;
> + int valid = 0;
> +
> + if (!di->lease_shared_gen)
> + return 0;
> + if (IS_ROOT(dentry))
> + return 0;
> +
> + rcu_read_lock();
> + dir = d_inode_rcu(dentry->d_parent);
> + ci = ceph_inode(dir);
If you hold dentry->d_lock (and you do here), then d_parent is stable
and you shouldn't need to use RCU.
> +
> + if (spin_trylock(&ci->i_ceph_lock)) {
> + if (atomic_read(&ci->i_shared_gen) == di->lease_shared_gen &&
> + __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 0))
> + valid = 1;
> + spin_unlock(&ci->i_ceph_lock);
> + } else {
> + valid = -EBUSY;
> + }
> + rcu_read_unlock();
> +
> + if (!valid)
> + di->lease_shared_gen = 0;
> + return valid;
> +}
> +
> /*
> * Check if directory-wide content lease/cap is valid.
> */
> @@ -1308,6 +1356,31 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
> return valid;
> }
>
> +/*
> + * Delete unused dentry that doesn't have valid lease
> + *
> + * Called under dentry->d_lock.
> + */
> +static int ceph_d_delete(const struct dentry *dentry)
> +{
> + struct ceph_dentry_info *di;
> +
> + /* won't release caps */
> + if (d_really_is_negative(dentry))
> + return 0;
> + if (ceph_snap(d_inode(dentry)) != CEPH_NOSNAP)
> + return 0;
> + /* vaild lease? */
> + di = ceph_dentry(dentry);
> + if (di) {
> + if (__dentry_lease_is_valid(di))
> + return 0;
> + if (__dir_lease_try_check(dentry))
> + return 0;
> + }
> + return 1;
> +}
> +
> /*
> * Release our ceph_dentry_info.
> */
> @@ -1531,6 +1604,7 @@ const struct inode_operations ceph_snapdir_iops = {
>
> const struct dentry_operations ceph_dentry_ops = {
> .d_revalidate = ceph_d_revalidate,
> + .d_delete = ceph_d_delete,
> .d_release = ceph_d_release,
> .d_prune = ceph_d_prune,
> .d_init = ceph_d_init,
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index f588b2d7b598..f75476e94d75 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -497,7 +497,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
> ci->i_wrbuffer_ref = 0;
> ci->i_wrbuffer_ref_head = 0;
> atomic_set(&ci->i_filelock_ref, 0);
> - atomic_set(&ci->i_shared_gen, 0);
> + atomic_set(&ci->i_shared_gen, 1);
> ci->i_rdcache_gen = 0;
> ci->i_rdcache_revoking = 0;
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 8f2d97e806b2..e5aea1db8d84 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -619,7 +619,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
> ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
>
> spin_lock_init(&s->s_gen_ttl_lock);
> - s->s_cap_gen = 0;
> + s->s_cap_gen = 1;
> s->s_cap_ttl = jiffies - 1;
>
> spin_lock_init(&s->s_cap_lock);
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index c4a79eadc55a..c0654e613fc0 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -594,7 +594,7 @@ extern u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
> struct ceph_inode_frag *pfrag,
> int *found);
>
> -static inline struct ceph_dentry_info *ceph_dentry(struct dentry *dentry)
> +static inline struct ceph_dentry_info *ceph_dentry(const struct dentry *dentry)
> {
> return (struct ceph_dentry_info *)dentry->d_fsdata;
> }
--
Jeff Layton <jlayton@xxxxxxxxxx>
