Re: [v2] ceph: using POOL FULL flag instead of OSDMAP FULL flag

From: Ilya Dryomov
Date: Thu Mar 12 2020 - 10:33:55 EST

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In reply to: Yanhu Cao: "Re: [v2] ceph: using POOL FULL flag instead of OSDMAP FULL flag"
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On Thu, Mar 12, 2020 at 9:40 AM Yanhu Cao <gmayyyha@xxxxxxxxx> wrote:
>
> On Wed, Mar 11, 2020 at 9:41 PM Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
> >
> > On Wed, Mar 11, 2020 at 10:55 AM Yanhu Cao <gmayyyha@xxxxxxxxx> wrote:
> > >
> > > On Tue, Mar 10, 2020 at 4:43 AM Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
> > > >
> > > > On Tue, Mar 3, 2020 at 10:33 AM Yanhu Cao <gmayyyha@xxxxxxxxx> wrote:
> > > > >
> > > > > CEPH_OSDMAP_FULL/NEARFULL has been deprecated since mimic, so it
> > > > > does not work well in new versions, added POOL flags to handle it.
> > > > >
> > > > > Signed-off-by: Yanhu Cao <gmayyyha@xxxxxxxxx>
> > > > > ---
> > > > > fs/ceph/file.c | 9 +++++++--
> > > > > include/linux/ceph/osd_client.h | 2 ++
> > > > > include/linux/ceph/osdmap.h | 3 ++-
> > > > > net/ceph/osd_client.c | 23 +++++++++++++----------
> > > > > 4 files changed, 24 insertions(+), 13 deletions(-)
> > > > >
> > > > > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > > > > index 7e0190b1f821..84ec44f9d77a 100644
> > > > > --- a/fs/ceph/file.c
> > > > > +++ b/fs/ceph/file.c
> > > > > @@ -1482,7 +1482,9 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
> > > > > }
> > > > >
> > > > > /* FIXME: not complete since it doesn't account for being at quota */
> > > > > - if (ceph_osdmap_flag(&fsc->client->osdc, CEPH_OSDMAP_FULL)) {
> > > > > + if (ceph_osdmap_flag(&fsc->client->osdc, CEPH_OSDMAP_FULL) ||
> > > > > + pool_flag(&fsc->client->osdc, ci->i_layout.pool_id,
> > > > > + CEPH_POOL_FLAG_FULL)) {
> > > > > err = -ENOSPC;
> > > > > goto out;
> > > > > }
> > > > > @@ -1575,7 +1577,10 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
> > > > > }
> > > > >
> > > > > if (written >= 0) {
> > > > > - if (ceph_osdmap_flag(&fsc->client->osdc, CEPH_OSDMAP_NEARFULL))
> > > > > + if (ceph_osdmap_flag(&fsc->client->osdc,
> > > > > + CEPH_OSDMAP_NEARFULL) ||
> > > > > + pool_flag(&fsc->client->osdc, ci->i_layout.pool_id,
> > > > > + CEPH_POOL_FLAG_NEARFULL))
> > > > > iocb->ki_flags |= IOCB_DSYNC;
> > > > > written = generic_write_sync(iocb, written);
> > > > > }
> > > > > diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
> > > > > index 5a62dbd3f4c2..be9007b93862 100644
> > > > > --- a/include/linux/ceph/osd_client.h
> > > > > +++ b/include/linux/ceph/osd_client.h
> > > > > @@ -375,6 +375,8 @@ static inline bool ceph_osdmap_flag(struct ceph_osd_client *osdc, int flag)
> > > > > return osdc->osdmap->flags & flag;
> > > > > }
> > > > >
> > > > > +bool pool_flag(struct ceph_osd_client *osdc, s64 pool_id, int flag);
> > > > > +
> > > > > extern int ceph_osdc_setup(void);
> > > > > extern void ceph_osdc_cleanup(void);
> > > > >
> > > > > diff --git a/include/linux/ceph/osdmap.h b/include/linux/ceph/osdmap.h
> > > > > index e081b56f1c1d..88faacc11f55 100644
> > > > > --- a/include/linux/ceph/osdmap.h
> > > > > +++ b/include/linux/ceph/osdmap.h
> > > > > @@ -36,7 +36,8 @@ int ceph_spg_compare(const struct ceph_spg *lhs, const struct ceph_spg *rhs);
> > > > >
> > > > > #define CEPH_POOL_FLAG_HASHPSPOOL (1ULL << 0) /* hash pg seed and pool id
> > > > > together */
> > > > > -#define CEPH_POOL_FLAG_FULL (1ULL << 1) /* pool is full */
> > > > > +#define CEPH_POOL_FLAG_FULL (1ULL << 1) /* pool is full */
> > > > > +#define CEPH_POOL_FLAG_NEARFULL (1ULL << 11) /* pool is nearfull */
> > > > >
> > > > > struct ceph_pg_pool_info {
> > > > > struct rb_node node;
> > > > > diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> > > > > index b68b376d8c2f..9ad2b96c3e78 100644
> > > > > --- a/net/ceph/osd_client.c
> > > > > +++ b/net/ceph/osd_client.c
> > > > > @@ -1447,9 +1447,9 @@ static void unlink_request(struct ceph_osd *osd, struct ceph_osd_request *req)
> > > > > atomic_dec(&osd->o_osdc->num_homeless);
> > > > > }
> > > > >
> > > > > -static bool __pool_full(struct ceph_pg_pool_info *pi)
> > > > > +static bool __pool_flag(struct ceph_pg_pool_info *pi, int flag)
> > > > > {
> > > > > - return pi->flags & CEPH_POOL_FLAG_FULL;
> > > > > + return pi->flags & flag;
> > > > > }
> > > > >
> > > > > static bool have_pool_full(struct ceph_osd_client *osdc)
> > > > > @@ -1460,14 +1460,14 @@ static bool have_pool_full(struct ceph_osd_client *osdc)
> > > > > struct ceph_pg_pool_info *pi =
> > > > > rb_entry(n, struct ceph_pg_pool_info, node);
> > > > >
> > > > > - if (__pool_full(pi))
> > > > > + if (__pool_flag(pi, CEPH_POOL_FLAG_FULL))
> > > > > return true;
> > > > > }
> > > > >
> > > > > return false;
> > > > > }
> > > > >
> > > > > -static bool pool_full(struct ceph_osd_client *osdc, s64 pool_id)
> > > > > +bool pool_flag(struct ceph_osd_client *osdc, s64 pool_id, int flag)
> > > > > {
> > > > > struct ceph_pg_pool_info *pi;
> > > > >
> > > > > @@ -1475,8 +1475,10 @@ static bool pool_full(struct ceph_osd_client *osdc, s64 pool_id)
> > > > > if (!pi)
> > > > > return false;
> > > > >
> > > > > - return __pool_full(pi);
> > > > > + return __pool_flag(pi, flag);
> > > > > }
> > > > > +EXPORT_SYMBOL(pool_flag);
> > > > > +
> > > > >
> > > > > /*
> > > > > * Returns whether a request should be blocked from being sent
> > > > > @@ -1489,7 +1491,7 @@ static bool target_should_be_paused(struct ceph_osd_client *osdc,
> > > > > bool pauserd = ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSERD);
> > > > > bool pausewr = ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR) ||
> > > > > ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
> > > > > - __pool_full(pi);
> > > > > + __pool_flag(pi, CEPH_POOL_FLAG_FULL);
> > > > >
> > > > > WARN_ON(pi->id != t->target_oloc.pool);
> > > > > return ((t->flags & CEPH_OSD_FLAG_READ) && pauserd) ||
> > > > > @@ -2320,7 +2322,8 @@ static void __submit_request(struct ceph_osd_request *req, bool wrlocked)
> > > > > !(req->r_flags & (CEPH_OSD_FLAG_FULL_TRY |
> > > > > CEPH_OSD_FLAG_FULL_FORCE)) &&
> > > > > (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
> > > > > - pool_full(osdc, req->r_t.base_oloc.pool))) {
> > > > > + pool_flag(osdc, req->r_t.base_oloc.pool,
> > > > > + CEPH_POOL_FLAG_FULL))) {
> > > > > dout("req %p full/pool_full\n", req);
> > > > > if (ceph_test_opt(osdc->client, ABORT_ON_FULL)) {
> > > > > err = -ENOSPC;
> > > > > @@ -2539,7 +2542,7 @@ static int abort_on_full_fn(struct ceph_osd_request *req, void *arg)
> > > > >
> > > > > if ((req->r_flags & CEPH_OSD_FLAG_WRITE) &&
> > > > > (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
> > > > > - pool_full(osdc, req->r_t.base_oloc.pool))) {
> > > > > + pool_flag(osdc, req->r_t.base_oloc.pool, CEPH_POOL_FLAG_FULL))) {
> > > > > if (!*victims) {
> > > > > update_epoch_barrier(osdc, osdc->osdmap->epoch);
> > > > > *victims = true;
> > > > > @@ -3707,7 +3710,7 @@ static void set_pool_was_full(struct ceph_osd_client *osdc)
> > > > > struct ceph_pg_pool_info *pi =
> > > > > rb_entry(n, struct ceph_pg_pool_info, node);
> > > > >
> > > > > - pi->was_full = __pool_full(pi);
> > > > > + pi->was_full = __pool_flag(pi, CEPH_POOL_FLAG_FULL);
> > > > > }
> > > > > }
> > > > >
> > > > > @@ -3719,7 +3722,7 @@ static bool pool_cleared_full(struct ceph_osd_client *osdc, s64 pool_id)
> > > > > if (!pi)
> > > > > return false;
> > > > >
> > > > > - return pi->was_full && !__pool_full(pi);
> > > > > + return pi->was_full && !__pool_flag(pi, CEPH_POOL_FLAG_FULL);
> > > > > }
> > > > >
> > > > > static enum calc_target_result
> > > >
> > > > Hi Yanhu,
> > > >
> > > > Sorry for a late reply.
> > > >
> > > > This adds some unnecessary churn and also exposes a helper that
> > > > must be called under osdc->lock without making that obvious. How
> > > > about the attached instead?
> > > >
> > > > ceph_pg_pool_flags() takes osdmap instead of osdc, making it clear
> > > > that the caller is resposibile for keeping the map stable.
> > > >
> > > > Thanks,
> > > >
> > > > Ilya
> > >
> > > net/ceph/osdmap.c
> > > --------------------------
> > > bool ceph_pg_pool_flags(struct ceph_osdmap *map, s64 pool_id, int flag)
> > > {
> > > struct ceph_pg_pool_info *pi;
> > >
> > > /* CEPH_OSDMAP_FULL|CEPH_OSDMAP_NEARFULL deprecated since mimic */
> > > if (flag & (CEPH_POOL_FLAG_FULL|CEPH_POOL_FLAG_NEARFULL))
> > > if (map->flags & (CEPH_OSDMAP_FULL|CEPH_OSDMAP_NEARFULL))
> > > return true;
> > >
> > > pi = ceph_pg_pool_by_id(map, pool_id);
> > > if (!pi)
> > > return false;
> > >
> > > return pi->flags & flag;
> > > }
> > >
> > > fs/ceph/file.c
> > > -----------------
> > > ceph_write_iter() {
> > > ...
> > > down_read(&osdc->lock);
> > > if (ceph_pg_pool_flags(osdc->osdmap, ci->i_layout.pool_id,
> > > CEPH_POOL_FLAG_FULL|CEPH_POOL_FLAG_FULL_QUOTA)) {
> > > err = -ENOSPC;
> > > up_read(&osdc->lock);
> > > goto out;
> > > }
> > > up_read(&osdc->lock);
> > > ...
> > > down_read(&osdc->lock);
> > > if (ceph_pg_pool_flags(osdc->osdmap, ci->i_layout.pool_id,
> > > CEPH_POOL_FLAG_NEARFULL))
> > > iocb->ki_flags |= IOCB_DSYNC;
> > > up_read(&osdc->lock);
> > > ...
> > > }
> > >
> > > how about this?
> >
> > Well, this takes osdc->lock and looks up ceph_pg_pool_info twice.
> > Given that these checks are inherently racy, I think doing it once
> > at the top makes more sense.
>
> be modified as follow.
>
> ceph_write_iter() {
> ...
> down_read(&osdc->lock);
> pi = ceph_pg_pool_by_id(osdc->osdmap, ci->i_layout.pool_id);
> if (!pi) {
> err = -ENOENT;
> up_read(&osdc->lock);
> goto out;
> }
> up_read(&osdc->lock);
> ...
> }

No, this won't work because as soon as you release osdc->lock, pi may
get invalidated.

>
> >
> > Also, I don't think this does what you intended it to do. Your
> > ceph_pg_pool_flags(..., CEPH_POOL_FLAG_FULL) returns true even if
> > the map only has CEPH_OSDMAP_NEARFULL, triggering early ENOSPC.
> >
>
> Ah... my mistake. According to OSDMAP/POOL flag to do respectively.
>
> if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
> ceph_pg_pool_flags(pi, CEPH_POOL_FLAG_FULL)) {

... and you may reference invalid memory here.

> err = -ENOSPC;
> goto out;
> }
>
> include/linux/ceph/osdmap.h
> --------------------------------------
> static inline bool ceph_pg_pool_flags(struct ceph_pg_pool_info *pi, int flag)
> {
> return pi->flags & flag;
> }

I'll go ahead with my version.

Thanks,

Ilya

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Previous message: Laurent Pinchart: "Re: [PATCH 1/2] dt-binding: Add DSI/LVDS tc358775 bridge bindings"
In reply to: Yanhu Cao: "Re: [v2] ceph: using POOL FULL flag instead of OSDMAP FULL flag"
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