]> git.ipfire.org Git - thirdparty/linux.git/commitdiff
ceph: add subvolume metrics collection and reporting
authorAlex Markuze <amarkuze@redhat.com>
Tue, 10 Feb 2026 09:06:26 +0000 (09:06 +0000)
committerIlya Dryomov <idryomov@gmail.com>
Tue, 21 Apr 2026 23:40:23 +0000 (01:40 +0200)
Add complete infrastructure for per-subvolume I/O metrics collection
and reporting to the MDS. This enables administrators to monitor I/O
patterns at the subvolume granularity, which is useful for multi-tenant
CephFS deployments.

This patch adds:
- CEPHFS_FEATURE_SUBVOLUME_METRICS feature flag for MDS negotiation
- CEPH_SUBVOLUME_ID_NONE constant (0) for unknown/unset state
- Red-black tree based metrics tracker for efficient per-subvolume
  aggregation with kmem_cache for entry allocations
- Wire format encoding matching the MDS C++ AggregatedIOMetrics struct
- Integration with the existing CLIENT_METRICS message
- Recording of I/O operations from file read/write and writeback paths
- Debugfs interfaces for monitoring (metrics/subvolumes, metrics/metric_features)

Metrics tracked per subvolume include:
- Read/write operation counts
- Read/write byte counts
- Read/write latency sums (for average calculation)

The metrics are periodically sent to the MDS as part of the existing
metrics reporting infrastructure when the MDS advertises support for
the SUBVOLUME_METRICS feature.

CEPH_SUBVOLUME_ID_NONE enforces subvolume_id immutability. Following
the FUSE client convention, 0 means unknown/unset. Once an inode has
a valid (non-zero) subvolume_id, it should not change during the
inode's lifetime.

Signed-off-by: Alex Markuze <amarkuze@redhat.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
12 files changed:
fs/ceph/Makefile
fs/ceph/addr.c
fs/ceph/debugfs.c
fs/ceph/file.c
fs/ceph/mds_client.c
fs/ceph/mds_client.h
fs/ceph/metric.c
fs/ceph/metric.h
fs/ceph/subvolume_metrics.c [new file with mode: 0644]
fs/ceph/subvolume_metrics.h [new file with mode: 0644]
fs/ceph/super.c
fs/ceph/super.h

index 1f77ca04c426fdb9be333b891ebbdee504e64d30..ebb29d11ac225958f9f50f967bf5d973a9023a5c 100644 (file)
@@ -8,7 +8,7 @@ obj-$(CONFIG_CEPH_FS) += ceph.o
 ceph-y := super.o inode.o dir.o file.o locks.o addr.o ioctl.o \
        export.o caps.o snap.o xattr.o quota.o io.o \
        mds_client.o mdsmap.o strings.o ceph_frag.o \
-       debugfs.o util.o metric.o
+       debugfs.o util.o metric.o subvolume_metrics.o
 
 ceph-$(CONFIG_CEPH_FSCACHE) += cache.o
 ceph-$(CONFIG_CEPH_FS_POSIX_ACL) += acl.o
index 44553556ac742bd61eb0d84c2cdf9431a1c58e23..5a4ad6a0d27057cee6a8ac151c992fa9c5bfdf8a 100644 (file)
@@ -19,6 +19,7 @@
 #include "mds_client.h"
 #include "cache.h"
 #include "metric.h"
+#include "subvolume_metrics.h"
 #include "crypto.h"
 #include <linux/ceph/osd_client.h>
 #include <linux/ceph/striper.h>
@@ -259,6 +260,10 @@ static void finish_netfs_read(struct ceph_osd_request *req)
                                        osd_data->length), false);
        }
        if (err > 0) {
+               ceph_subvolume_metrics_record_io(fsc->mdsc, ceph_inode(inode),
+                                                false, err,
+                                                req->r_start_latency,
+                                                req->r_end_latency);
                subreq->transferred = err;
                err = 0;
        }
@@ -823,6 +828,10 @@ static int write_folio_nounlock(struct folio *folio,
 
        ceph_update_write_metrics(&fsc->mdsc->metric, req->r_start_latency,
                                  req->r_end_latency, len, err);
+       if (err >= 0 && len > 0)
+               ceph_subvolume_metrics_record_io(fsc->mdsc, ci, true, len,
+                                                req->r_start_latency,
+                                                req->r_end_latency);
        fscrypt_free_bounce_page(bounce_page);
        ceph_osdc_put_request(req);
        if (err == 0)
@@ -963,6 +972,11 @@ static void writepages_finish(struct ceph_osd_request *req)
        ceph_update_write_metrics(&fsc->mdsc->metric, req->r_start_latency,
                                  req->r_end_latency, len, rc);
 
+       if (rc >= 0 && len > 0)
+               ceph_subvolume_metrics_record_io(mdsc, ci, true, len,
+                                                req->r_start_latency,
+                                                req->r_end_latency);
+
        ceph_put_wrbuffer_cap_refs(ci, total_pages, snapc);
 
        osd_data = osd_req_op_extent_osd_data(req, 0);
index 7dc3077902401ed00c7f2e353d7f948964f7d65d..e2463f93cf6b5c90ae5e255c1d034f328fa37515 100644 (file)
@@ -9,11 +9,13 @@
 #include <linux/seq_file.h>
 #include <linux/math64.h>
 #include <linux/ktime.h>
+#include <linux/atomic.h>
 
 #include <linux/ceph/libceph.h>
 #include <linux/ceph/mon_client.h>
 #include <linux/ceph/auth.h>
 #include <linux/ceph/debugfs.h>
+#include <linux/ceph/decode.h>
 
 #include "super.h"
 
 
 #include "mds_client.h"
 #include "metric.h"
+#include "subvolume_metrics.h"
+
+/**
+ * struct ceph_session_feature_desc - Maps feature bits to names for debugfs
+ * @bit: Feature bit number from enum ceph_feature_type (see mds_client.h)
+ * @name: Human-readable feature name for debugfs output
+ *
+ * Used by metric_features_show() to display negotiated session features.
+ */
+struct ceph_session_feature_desc {
+       unsigned int bit;
+       const char *name;
+};
+
+static const struct ceph_session_feature_desc ceph_session_feature_table[] = {
+       { CEPHFS_FEATURE_METRIC_COLLECT, "METRIC_COLLECT" },
+       { CEPHFS_FEATURE_REPLY_ENCODING, "REPLY_ENCODING" },
+       { CEPHFS_FEATURE_RECLAIM_CLIENT, "RECLAIM_CLIENT" },
+       { CEPHFS_FEATURE_LAZY_CAP_WANTED, "LAZY_CAP_WANTED" },
+       { CEPHFS_FEATURE_MULTI_RECONNECT, "MULTI_RECONNECT" },
+       { CEPHFS_FEATURE_DELEG_INO, "DELEG_INO" },
+       { CEPHFS_FEATURE_ALTERNATE_NAME, "ALTERNATE_NAME" },
+       { CEPHFS_FEATURE_NOTIFY_SESSION_STATE, "NOTIFY_SESSION_STATE" },
+       { CEPHFS_FEATURE_OP_GETVXATTR, "OP_GETVXATTR" },
+       { CEPHFS_FEATURE_32BITS_RETRY_FWD, "32BITS_RETRY_FWD" },
+       { CEPHFS_FEATURE_NEW_SNAPREALM_INFO, "NEW_SNAPREALM_INFO" },
+       { CEPHFS_FEATURE_HAS_OWNER_UIDGID, "HAS_OWNER_UIDGID" },
+       { CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK, "MDS_AUTH_CAPS_CHECK" },
+       { CEPHFS_FEATURE_SUBVOLUME_METRICS, "SUBVOLUME_METRICS" },
+};
 
 static int mdsmap_show(struct seq_file *s, void *p)
 {
@@ -360,6 +392,59 @@ static int status_show(struct seq_file *s, void *p)
        return 0;
 }
 
+static int subvolume_metrics_show(struct seq_file *s, void *p)
+{
+       struct ceph_fs_client *fsc = s->private;
+       struct ceph_mds_client *mdsc = fsc->mdsc;
+       struct ceph_subvol_metric_snapshot *snapshot = NULL;
+       u32 nr = 0;
+       u64 total_sent = 0;
+       u64 nonzero_sends = 0;
+       u32 i;
+
+       if (!mdsc) {
+               seq_puts(s, "mds client unavailable\n");
+               return 0;
+       }
+
+       mutex_lock(&mdsc->subvol_metrics_last_mutex);
+       if (mdsc->subvol_metrics_last && mdsc->subvol_metrics_last_nr) {
+               nr = mdsc->subvol_metrics_last_nr;
+               snapshot = kmemdup_array(mdsc->subvol_metrics_last, nr,
+                                        sizeof(*snapshot), GFP_KERNEL);
+               if (!snapshot)
+                       nr = 0;
+       }
+       total_sent = mdsc->subvol_metrics_sent;
+       nonzero_sends = mdsc->subvol_metrics_nonzero_sends;
+       mutex_unlock(&mdsc->subvol_metrics_last_mutex);
+
+       seq_puts(s, "Last sent subvolume metrics:\n");
+       if (!nr) {
+               seq_puts(s, "  (none)\n");
+       } else {
+               seq_puts(s, "  subvol_id          rd_ops    wr_ops    rd_bytes       wr_bytes       rd_lat_us      wr_lat_us\n");
+               for (i = 0; i < nr; i++) {
+                       const struct ceph_subvol_metric_snapshot *e = &snapshot[i];
+
+                       seq_printf(s, "  %-18llu %-9llu %-9llu %-14llu %-14llu %-14llu %-14llu\n",
+                                  e->subvolume_id,
+                                  e->read_ops, e->write_ops,
+                                  e->read_bytes, e->write_bytes,
+                                  e->read_latency_us, e->write_latency_us);
+               }
+       }
+       kfree(snapshot);
+
+       seq_puts(s, "\nStatistics:\n");
+       seq_printf(s, "  entries_sent:      %llu\n", total_sent);
+       seq_printf(s, "  non_zero_sends:    %llu\n", nonzero_sends);
+
+       seq_puts(s, "\nPending (unsent) subvolume metrics:\n");
+       ceph_subvolume_metrics_dump(&mdsc->subvol_metrics, s);
+       return 0;
+}
+
 DEFINE_SHOW_ATTRIBUTE(mdsmap);
 DEFINE_SHOW_ATTRIBUTE(mdsc);
 DEFINE_SHOW_ATTRIBUTE(caps);
@@ -369,7 +454,72 @@ DEFINE_SHOW_ATTRIBUTE(metrics_file);
 DEFINE_SHOW_ATTRIBUTE(metrics_latency);
 DEFINE_SHOW_ATTRIBUTE(metrics_size);
 DEFINE_SHOW_ATTRIBUTE(metrics_caps);
+DEFINE_SHOW_ATTRIBUTE(subvolume_metrics);
+
+static int metric_features_show(struct seq_file *s, void *p)
+{
+       struct ceph_fs_client *fsc = s->private;
+       struct ceph_mds_client *mdsc = fsc->mdsc;
+       unsigned long session_features = 0;
+       bool have_session = false;
+       bool metric_collect = false;
+       bool subvol_support = false;
+       bool metrics_enabled = false;
+       bool subvol_enabled = false;
+       int i;
+
+       if (!mdsc) {
+               seq_puts(s, "mds client unavailable\n");
+               return 0;
+       }
+
+       mutex_lock(&mdsc->mutex);
+       if (mdsc->metric.session) {
+               have_session = true;
+               session_features = mdsc->metric.session->s_features;
+       }
+       mutex_unlock(&mdsc->mutex);
+
+       if (have_session) {
+               metric_collect =
+                       test_bit(CEPHFS_FEATURE_METRIC_COLLECT,
+                                &session_features);
+               subvol_support =
+                       test_bit(CEPHFS_FEATURE_SUBVOLUME_METRICS,
+                                &session_features);
+       }
+
+       metrics_enabled = !disable_send_metrics && have_session && metric_collect;
+       subvol_enabled = metrics_enabled && subvol_support;
+
+       seq_printf(s,
+                  "metrics_enabled: %s (disable_send_metrics=%d, session=%s, metric_collect=%s)\n",
+                  metrics_enabled ? "yes" : "no",
+                  disable_send_metrics ? 1 : 0,
+                  have_session ? "yes" : "no",
+                  metric_collect ? "yes" : "no");
+       seq_printf(s, "subvolume_metrics_enabled: %s\n",
+                  subvol_enabled ? "yes" : "no");
+       seq_printf(s, "session_feature_bits: 0x%lx\n", session_features);
+
+       if (!have_session) {
+               seq_puts(s, "(no active MDS session for metrics)\n");
+               return 0;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(ceph_session_feature_table); i++) {
+               const struct ceph_session_feature_desc *desc =
+                       &ceph_session_feature_table[i];
+               bool set = test_bit(desc->bit, &session_features);
+
+               seq_printf(s, "  %-24s : %s\n", desc->name,
+                          set ? "yes" : "no");
+       }
+
+       return 0;
+}
 
+DEFINE_SHOW_ATTRIBUTE(metric_features);
 
 /*
  * debugfs
@@ -404,6 +554,7 @@ void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
        debugfs_remove(fsc->debugfs_caps);
        debugfs_remove(fsc->debugfs_status);
        debugfs_remove(fsc->debugfs_mdsc);
+       debugfs_remove(fsc->debugfs_subvolume_metrics);
        debugfs_remove_recursive(fsc->debugfs_metrics_dir);
        doutc(fsc->client, "done\n");
 }
@@ -468,6 +619,12 @@ void ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
                            &metrics_size_fops);
        debugfs_create_file("caps", 0400, fsc->debugfs_metrics_dir, fsc,
                            &metrics_caps_fops);
+       debugfs_create_file("metric_features", 0400, fsc->debugfs_metrics_dir,
+                           fsc, &metric_features_fops);
+       fsc->debugfs_subvolume_metrics =
+               debugfs_create_file("subvolumes", 0400,
+                                   fsc->debugfs_metrics_dir, fsc,
+                                   &subvolume_metrics_fops);
        doutc(fsc->client, "done\n");
 }
 
index 5e7c73a29aa3e94f86689e8f7d454669805883c5..d54d71669176bd16ce02e4ad670c8a9c5c269ad7 100644 (file)
 #include "cache.h"
 #include "io.h"
 #include "metric.h"
+#include "subvolume_metrics.h"
+
+/*
+ * Record I/O for subvolume metrics tracking.
+ *
+ * Callers must ensure bytes > 0 for reads (ret > 0 check) to avoid counting
+ * EOF as an I/O operation. For writes, the condition is (ret >= 0 && len > 0).
+ */
+static inline void ceph_record_subvolume_io(struct inode *inode, bool is_write,
+                                           ktime_t start, ktime_t end,
+                                           size_t bytes)
+{
+       if (!bytes)
+               return;
+
+       ceph_subvolume_metrics_record_io(ceph_sb_to_mdsc(inode->i_sb),
+                                        ceph_inode(inode),
+                                        is_write, bytes, start, end);
+}
 
 static __le32 ceph_flags_sys2wire(struct ceph_mds_client *mdsc, u32 flags)
 {
@@ -1140,6 +1159,15 @@ ssize_t __ceph_sync_read(struct inode *inode, loff_t *ki_pos,
                                         req->r_start_latency,
                                         req->r_end_latency,
                                         read_len, ret);
+               /*
+                * Only record subvolume metrics for actual bytes read.
+                * ret == 0 means EOF (no data), not an I/O operation.
+                */
+               if (ret > 0)
+                       ceph_record_subvolume_io(inode, false,
+                                                req->r_start_latency,
+                                                req->r_end_latency,
+                                                ret);
 
                if (ret > 0)
                        objver = req->r_version;
@@ -1385,12 +1413,23 @@ static void ceph_aio_complete_req(struct ceph_osd_request *req)
 
        /* r_start_latency == 0 means the request was not submitted */
        if (req->r_start_latency) {
-               if (aio_req->write)
+               if (aio_req->write) {
                        ceph_update_write_metrics(metric, req->r_start_latency,
                                                  req->r_end_latency, len, rc);
-               else
+                       if (rc >= 0 && len)
+                               ceph_record_subvolume_io(inode, true,
+                                                        req->r_start_latency,
+                                                        req->r_end_latency,
+                                                        len);
+               } else {
                        ceph_update_read_metrics(metric, req->r_start_latency,
                                                 req->r_end_latency, len, rc);
+                       if (rc > 0)
+                               ceph_record_subvolume_io(inode, false,
+                                                        req->r_start_latency,
+                                                        req->r_end_latency,
+                                                        rc);
+               }
        }
 
        put_bvecs(osd_data->bvec_pos.bvecs, osd_data->num_bvecs,
@@ -1614,12 +1653,23 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
                ceph_osdc_start_request(req->r_osdc, req);
                ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
 
-               if (write)
+               if (write) {
                        ceph_update_write_metrics(metric, req->r_start_latency,
                                                  req->r_end_latency, len, ret);
-               else
+                       if (ret >= 0 && len)
+                               ceph_record_subvolume_io(inode, true,
+                                                        req->r_start_latency,
+                                                        req->r_end_latency,
+                                                        len);
+               } else {
                        ceph_update_read_metrics(metric, req->r_start_latency,
                                                 req->r_end_latency, len, ret);
+                       if (ret > 0)
+                               ceph_record_subvolume_io(inode, false,
+                                                        req->r_start_latency,
+                                                        req->r_end_latency,
+                                                        ret);
+               }
 
                size = i_size_read(inode);
                if (!write) {
@@ -1872,6 +1922,11 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
                                                 req->r_start_latency,
                                                 req->r_end_latency,
                                                 read_len, ret);
+                       if (ret > 0)
+                               ceph_record_subvolume_io(inode, false,
+                                                        req->r_start_latency,
+                                                        req->r_end_latency,
+                                                        ret);
 
                        /* Ok if object is not already present */
                        if (ret == -ENOENT) {
@@ -2036,6 +2091,11 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 
                ceph_update_write_metrics(&fsc->mdsc->metric, req->r_start_latency,
                                          req->r_end_latency, len, ret);
+               if (ret >= 0 && write_len)
+                       ceph_record_subvolume_io(inode, true,
+                                                req->r_start_latency,
+                                                req->r_end_latency,
+                                                write_len);
                ceph_osdc_put_request(req);
                if (ret != 0) {
                        doutc(cl, "osd write returned %d\n", ret);
index 267bd37eb608b1a71938ba3d4416b682ca1592b8..fa476497d41d25dd015100d5b41866e1218852db 100644 (file)
@@ -68,6 +68,21 @@ static void ceph_cap_reclaim_work(struct work_struct *work);
 
 static const struct ceph_connection_operations mds_con_ops;
 
+static void ceph_metric_bind_session(struct ceph_mds_client *mdsc,
+                                    struct ceph_mds_session *session)
+{
+       struct ceph_mds_session *old;
+
+       if (!mdsc || !session || disable_send_metrics)
+               return;
+
+       old = mdsc->metric.session;
+       mdsc->metric.session = ceph_get_mds_session(session);
+       if (old)
+               ceph_put_mds_session(old);
+
+       metric_schedule_delayed(&mdsc->metric);
+}
 
 /*
  * mds reply parsing
@@ -4347,6 +4362,11 @@ skip_cap_auths:
                }
                mdsc->s_cap_auths_num = cap_auths_num;
                mdsc->s_cap_auths = cap_auths;
+
+               session->s_features = features;
+               if (test_bit(CEPHFS_FEATURE_METRIC_COLLECT,
+                            &session->s_features))
+                       ceph_metric_bind_session(mdsc, session);
        }
        if (op == CEPH_SESSION_CLOSE) {
                ceph_get_mds_session(session);
@@ -4373,7 +4393,11 @@ skip_cap_auths:
                        pr_info_client(cl, "mds%d reconnect success\n",
                                       session->s_mds);
 
-               session->s_features = features;
+               if (test_bit(CEPHFS_FEATURE_SUBVOLUME_METRICS,
+                            &session->s_features))
+                       ceph_subvolume_metrics_enable(&mdsc->subvol_metrics, true);
+               else
+                       ceph_subvolume_metrics_enable(&mdsc->subvol_metrics, false);
                if (session->s_state == CEPH_MDS_SESSION_OPEN) {
                        pr_notice_client(cl, "mds%d is already opened\n",
                                         session->s_mds);
@@ -5616,6 +5640,12 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
        err = ceph_metric_init(&mdsc->metric);
        if (err)
                goto err_mdsmap;
+       ceph_subvolume_metrics_init(&mdsc->subvol_metrics);
+       mutex_init(&mdsc->subvol_metrics_last_mutex);
+       mdsc->subvol_metrics_last = NULL;
+       mdsc->subvol_metrics_last_nr = 0;
+       mdsc->subvol_metrics_sent = 0;
+       mdsc->subvol_metrics_nonzero_sends = 0;
 
        spin_lock_init(&mdsc->dentry_list_lock);
        INIT_LIST_HEAD(&mdsc->dentry_leases);
@@ -6149,6 +6179,8 @@ void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
        ceph_mdsc_stop(mdsc);
 
        ceph_metric_destroy(&mdsc->metric);
+       ceph_subvolume_metrics_destroy(&mdsc->subvol_metrics);
+       kfree(mdsc->subvol_metrics_last);
 
        fsc->mdsc = NULL;
        kfree(mdsc);
index bd3690baa65c0203ec793690c7d295fc02ead139..4e6c87f8414cc8438d4433562eaa1503a13f09d8 100644 (file)
@@ -18,6 +18,7 @@
 
 #include "mdsmap.h"
 #include "metric.h"
+#include "subvolume_metrics.h"
 #include "super.h"
 
 /* The first 8 bits are reserved for old ceph releases */
@@ -36,8 +37,9 @@ enum ceph_feature_type {
        CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
        CEPHFS_FEATURE_HAS_OWNER_UIDGID,
        CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK,
+       CEPHFS_FEATURE_SUBVOLUME_METRICS,
 
-       CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK,
+       CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_SUBVOLUME_METRICS,
 };
 
 #define CEPHFS_FEATURES_CLIENT_SUPPORTED {     \
@@ -54,6 +56,7 @@ enum ceph_feature_type {
        CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
        CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
        CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK,     \
+       CEPHFS_FEATURE_SUBVOLUME_METRICS,       \
 }
 
 /*
@@ -537,6 +540,14 @@ struct ceph_mds_client {
        struct list_head  dentry_dir_leases; /* lru list */
 
        struct ceph_client_metric metric;
+       struct ceph_subvolume_metrics_tracker subvol_metrics;
+
+       /* Subvolume metrics send tracking */
+       struct mutex            subvol_metrics_last_mutex;
+       struct ceph_subvol_metric_snapshot *subvol_metrics_last;
+       u32                     subvol_metrics_last_nr;
+       u64                     subvol_metrics_sent;
+       u64                     subvol_metrics_nonzero_sends;
 
        spinlock_t              snapid_map_lock;
        struct rb_root          snapid_map_tree;
index 871c1090e520112d4a5641ab941bc1848b9a5e3d..b6450fdace94465232cf361916d81f1e4425c732 100644 (file)
@@ -4,10 +4,84 @@
 #include <linux/types.h>
 #include <linux/percpu_counter.h>
 #include <linux/math64.h>
+#include <linux/ratelimit.h>
+
+#include <linux/ceph/decode.h>
 
 #include "metric.h"
 #include "mds_client.h"
 
+static bool metrics_disable_warned;
+
+static inline u32 ceph_subvolume_entry_payload_len(void)
+{
+       return sizeof(struct ceph_subvolume_metric_entry_wire);
+}
+
+static inline u32 ceph_subvolume_entry_encoded_len(void)
+{
+       return CEPH_ENCODING_START_BLK_LEN +
+               ceph_subvolume_entry_payload_len();
+}
+
+static inline u32 ceph_subvolume_outer_payload_len(u32 nr_subvols)
+{
+       /* count is encoded as le64 (size_t on wire) to match FUSE client */
+       return sizeof(__le64) +
+               nr_subvols * ceph_subvolume_entry_encoded_len();
+}
+
+static inline u32 ceph_subvolume_metric_data_len(u32 nr_subvols)
+{
+       return CEPH_ENCODING_START_BLK_LEN +
+               ceph_subvolume_outer_payload_len(nr_subvols);
+}
+
+static inline u32 ceph_subvolume_clamp_u32(u64 val)
+{
+       return val > U32_MAX ? U32_MAX : (u32)val;
+}
+
+static void ceph_init_subvolume_wire_entry(
+       struct ceph_subvolume_metric_entry_wire *dst,
+       const struct ceph_subvol_metric_snapshot *src)
+{
+       dst->subvolume_id = cpu_to_le64(src->subvolume_id);
+       dst->read_ops = cpu_to_le32(ceph_subvolume_clamp_u32(src->read_ops));
+       dst->write_ops = cpu_to_le32(ceph_subvolume_clamp_u32(src->write_ops));
+       dst->read_bytes = cpu_to_le64(src->read_bytes);
+       dst->write_bytes = cpu_to_le64(src->write_bytes);
+       dst->read_latency_us = cpu_to_le64(src->read_latency_us);
+       dst->write_latency_us = cpu_to_le64(src->write_latency_us);
+       dst->time_stamp = 0;
+}
+
+static int ceph_encode_subvolume_metrics(void **p, void *end,
+                                        struct ceph_subvol_metric_snapshot *subvols,
+                                        u32 nr_subvols)
+{
+       u32 i;
+
+       ceph_start_encoding(p, 1, 1,
+                           ceph_subvolume_outer_payload_len(nr_subvols));
+       /* count is encoded as le64 (size_t on wire) to match FUSE client */
+       ceph_encode_64_safe(p, end, (u64)nr_subvols, enc_err);
+
+       for (i = 0; i < nr_subvols; i++) {
+               struct ceph_subvolume_metric_entry_wire wire_entry;
+
+               ceph_init_subvolume_wire_entry(&wire_entry, &subvols[i]);
+               ceph_start_encoding(p, 1, 1,
+                                   ceph_subvolume_entry_payload_len());
+               ceph_encode_copy_safe(p, end, &wire_entry,
+                                     sizeof(wire_entry), enc_err);
+       }
+
+       return 0;
+enc_err:
+       return -ERANGE;
+}
+
 static void ktime_to_ceph_timespec(struct ceph_timespec *ts, ktime_t val)
 {
        struct timespec64 t = ktime_to_timespec64(val);
@@ -29,10 +103,14 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
        struct ceph_read_io_size *rsize;
        struct ceph_write_io_size *wsize;
        struct ceph_client_metric *m = &mdsc->metric;
+       struct ceph_subvol_metric_snapshot *subvols = NULL;
        u64 nr_caps = atomic64_read(&m->total_caps);
        u32 header_len = sizeof(struct ceph_metric_header);
        struct ceph_client *cl = mdsc->fsc->client;
        struct ceph_msg *msg;
+       u32 nr_subvols = 0;
+       size_t subvol_len = 0;
+       void *cursor;
        s64 sum;
        s32 items = 0;
        s32 len;
@@ -45,15 +123,42 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
        }
        mutex_unlock(&mdsc->mutex);
 
+       if (ceph_subvolume_metrics_enabled(&mdsc->subvol_metrics) &&
+           test_bit(CEPHFS_FEATURE_SUBVOLUME_METRICS, &s->s_features)) {
+               int ret;
+
+               ret = ceph_subvolume_metrics_snapshot(&mdsc->subvol_metrics,
+                                                     &subvols, &nr_subvols,
+                                                     true);
+               if (ret) {
+                       pr_warn_client(cl, "failed to snapshot subvolume metrics: %d\n",
+                                      ret);
+                       /*
+                        * On error, ceph_subvolume_metrics_snapshot() guarantees
+                        * *out = NULL and *nr = 0 at function entry, so subvols
+                        * is already NULL here - no cleanup needed.
+                        */
+                       nr_subvols = 0;
+                       subvols = NULL;
+               }
+       }
+
+       if (nr_subvols) {
+               /* type (le32) + ENCODE_START payload - no metric header */
+               subvol_len = sizeof(__le32) +
+                            ceph_subvolume_metric_data_len(nr_subvols);
+       }
+
        len = sizeof(*head) + sizeof(*cap) + sizeof(*read) + sizeof(*write)
              + sizeof(*meta) + sizeof(*dlease) + sizeof(*files)
              + sizeof(*icaps) + sizeof(*inodes) + sizeof(*rsize)
-             + sizeof(*wsize);
+             + sizeof(*wsize) + subvol_len;
 
        msg = ceph_msg_new(CEPH_MSG_CLIENT_METRICS, len, GFP_NOFS, true);
        if (!msg) {
                pr_err_client(cl, "to mds%d, failed to allocate message\n",
                              s->s_mds);
+               kfree(subvols);
                return false;
        }
 
@@ -172,13 +277,56 @@ static bool ceph_mdsc_send_metrics(struct ceph_mds_client *mdsc,
        wsize->total_size = cpu_to_le64(m->metric[METRIC_WRITE].size_sum);
        items++;
 
+       cursor = wsize + 1;
+
+       if (nr_subvols) {
+               void *payload;
+               void *payload_end;
+               int ret;
+
+               /* Emit only the type (le32), no ver/compat/data_len */
+               ceph_encode_32(&cursor, CLIENT_METRIC_TYPE_SUBVOLUME_METRICS);
+               items++;
+
+               payload = cursor;
+               payload_end = (char *)payload +
+                             ceph_subvolume_metric_data_len(nr_subvols);
+
+               ret = ceph_encode_subvolume_metrics(&payload, payload_end,
+                                                   subvols, nr_subvols);
+               if (ret) {
+                       pr_warn_client(cl,
+                                      "failed to encode subvolume metrics\n");
+                       kfree(subvols);
+                       ceph_msg_put(msg);
+                       return false;
+               }
+
+               WARN_ON(payload != payload_end);
+               cursor = payload;
+       }
+
        put_unaligned_le32(items, &head->num);
-       msg->front.iov_len = len;
+       msg->front.iov_len = (char *)cursor - (char *)head;
        msg->hdr.version = cpu_to_le16(1);
        msg->hdr.compat_version = cpu_to_le16(1);
        msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
+
        ceph_con_send(&s->s_con, msg);
 
+       if (nr_subvols) {
+               mutex_lock(&mdsc->subvol_metrics_last_mutex);
+               kfree(mdsc->subvol_metrics_last);
+               mdsc->subvol_metrics_last = subvols;
+               mdsc->subvol_metrics_last_nr = nr_subvols;
+               mdsc->subvol_metrics_sent += nr_subvols;
+               mdsc->subvol_metrics_nonzero_sends++;
+               mutex_unlock(&mdsc->subvol_metrics_last_mutex);
+
+               subvols = NULL;
+       }
+       kfree(subvols);
+
        return true;
 }
 
@@ -198,9 +346,20 @@ static void metric_get_session(struct ceph_mds_client *mdsc)
                 * Skip it if MDS doesn't support the metric collection,
                 * or the MDS will close the session's socket connection
                 * directly when it get this message.
+                *
+                * Also skip sessions that don't support SUBVOLUME_METRICS
+                * when subvolume metrics collection is enabled. This ensures
+                * we only send subvolume metrics to MDSs that understand them.
+                * If no session supports the feature, metrics won't be sent.
                 */
                if (check_session_state(s) &&
                    test_bit(CEPHFS_FEATURE_METRIC_COLLECT, &s->s_features)) {
+                       if (ceph_subvolume_metrics_enabled(&mdsc->subvol_metrics) &&
+                           !test_bit(CEPHFS_FEATURE_SUBVOLUME_METRICS,
+                                     &s->s_features)) {
+                               ceph_put_mds_session(s);
+                               continue;
+                       }
                        mdsc->metric.session = s;
                        break;
                }
@@ -217,8 +376,17 @@ static void metric_delayed_work(struct work_struct *work)
        struct ceph_mds_client *mdsc =
                container_of(m, struct ceph_mds_client, metric);
 
-       if (mdsc->stopping || disable_send_metrics)
+       if (mdsc->stopping)
+               return;
+
+       if (disable_send_metrics) {
+               if (!metrics_disable_warned) {
+                       pr_info("ceph: metrics sending disabled via module parameter\n");
+                       metrics_disable_warned = true;
+               }
                return;
+       }
+       metrics_disable_warned = false;
 
        if (!m->session || !check_session_state(m->session)) {
                if (m->session) {
@@ -227,10 +395,13 @@ static void metric_delayed_work(struct work_struct *work)
                }
                metric_get_session(mdsc);
        }
-       if (m->session) {
+
+       if (m->session)
                ceph_mdsc_send_metrics(mdsc, m->session);
-               metric_schedule_delayed(m);
-       }
+       else
+               pr_warn_ratelimited("ceph: metrics worker has no MDS session\n");
+
+       metric_schedule_delayed(m);
 }
 
 int ceph_metric_init(struct ceph_client_metric *m)
index 0d0c44bd3332b920517f8338a158d0ae3068935d..519cd4d47aaafac5743eb567b03619b21a5bcac8 100644 (file)
@@ -25,8 +25,9 @@ enum ceph_metric_type {
        CLIENT_METRIC_TYPE_STDEV_WRITE_LATENCY,
        CLIENT_METRIC_TYPE_AVG_METADATA_LATENCY,
        CLIENT_METRIC_TYPE_STDEV_METADATA_LATENCY,
+       CLIENT_METRIC_TYPE_SUBVOLUME_METRICS,
 
-       CLIENT_METRIC_TYPE_MAX = CLIENT_METRIC_TYPE_STDEV_METADATA_LATENCY,
+       CLIENT_METRIC_TYPE_MAX = CLIENT_METRIC_TYPE_SUBVOLUME_METRICS,
 };
 
 /*
@@ -50,6 +51,7 @@ enum ceph_metric_type {
        CLIENT_METRIC_TYPE_STDEV_WRITE_LATENCY,    \
        CLIENT_METRIC_TYPE_AVG_METADATA_LATENCY,   \
        CLIENT_METRIC_TYPE_STDEV_METADATA_LATENCY, \
+       CLIENT_METRIC_TYPE_SUBVOLUME_METRICS,      \
                                                   \
        CLIENT_METRIC_TYPE_MAX,                    \
 }
@@ -139,6 +141,41 @@ struct ceph_write_io_size {
        __le64 total_size;
 } __packed;
 
+/**
+ * struct ceph_subvolume_metric_entry_wire - On-wire format sent to MDS
+ * @subvolume_id: Subvolume identifier
+ * @read_ops: Read operation count (32-bit, clamped from 64-bit internal)
+ * @write_ops: Write operation count (32-bit, clamped from 64-bit internal)
+ * @read_bytes: Total bytes read
+ * @write_bytes: Total bytes written
+ * @read_latency_us: Cumulative read latency in microseconds
+ * @write_latency_us: Cumulative write latency in microseconds
+ * @time_stamp: Collection timestamp (currently unused, set to 0)
+ *
+ * Wire format must match C++ AggregatedIOMetrics struct in MDS.
+ */
+struct ceph_subvolume_metric_entry_wire {
+       __le64 subvolume_id;
+       __le32 read_ops;
+       __le32 write_ops;
+       __le64 read_bytes;
+       __le64 write_bytes;
+       __le64 read_latency_us;
+       __le64 write_latency_us;
+       __le64 time_stamp;
+} __packed;
+
+/* Old struct kept for internal tracking, not used on wire */
+struct ceph_subvolume_metric_entry {
+       __le64 subvolume_id;
+       __le64 read_ops;
+       __le64 write_ops;
+       __le64 read_bytes;
+       __le64 write_bytes;
+       __le64 read_latency_us;
+       __le64 write_latency_us;
+} __packed;
+
 struct ceph_metric_head {
        __le32 num;     /* the number of metrics that will be sent */
 } __packed;
diff --git a/fs/ceph/subvolume_metrics.c b/fs/ceph/subvolume_metrics.c
new file mode 100644 (file)
index 0000000..03fda1f
--- /dev/null
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/math64.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+
+#include "subvolume_metrics.h"
+#include "mds_client.h"
+#include "super.h"
+
+/**
+ * struct ceph_subvol_metric_rb_entry - Per-subvolume I/O metrics node
+ * @node: Red-black tree linkage for tracker->tree
+ * @subvolume_id: Subvolume identifier (key for rb-tree lookup)
+ * @read_ops: Accumulated read operation count since last snapshot
+ * @write_ops: Accumulated write operation count since last snapshot
+ * @read_bytes: Accumulated bytes read since last snapshot
+ * @write_bytes: Accumulated bytes written since last snapshot
+ * @read_latency_us: Sum of read latencies in microseconds
+ * @write_latency_us: Sum of write latencies in microseconds
+ */
+struct ceph_subvol_metric_rb_entry {
+       struct rb_node node;
+       u64 subvolume_id;
+       u64 read_ops;
+       u64 write_ops;
+       u64 read_bytes;
+       u64 write_bytes;
+       u64 read_latency_us;
+       u64 write_latency_us;
+};
+
+static struct kmem_cache *ceph_subvol_metric_entry_cachep;
+
+void ceph_subvolume_metrics_init(struct ceph_subvolume_metrics_tracker *tracker)
+{
+       spin_lock_init(&tracker->lock);
+       tracker->tree = RB_ROOT_CACHED;
+       tracker->nr_entries = 0;
+       tracker->enabled = false;
+       atomic64_set(&tracker->snapshot_attempts, 0);
+       atomic64_set(&tracker->snapshot_empty, 0);
+       atomic64_set(&tracker->snapshot_failures, 0);
+       atomic64_set(&tracker->record_calls, 0);
+       atomic64_set(&tracker->record_disabled, 0);
+       atomic64_set(&tracker->record_no_subvol, 0);
+       atomic64_set(&tracker->total_read_ops, 0);
+       atomic64_set(&tracker->total_read_bytes, 0);
+       atomic64_set(&tracker->total_write_ops, 0);
+       atomic64_set(&tracker->total_write_bytes, 0);
+}
+
+static struct ceph_subvol_metric_rb_entry *
+__lookup_entry(struct ceph_subvolume_metrics_tracker *tracker, u64 subvol_id)
+{
+       struct rb_node *node;
+
+       node = tracker->tree.rb_root.rb_node;
+       while (node) {
+               struct ceph_subvol_metric_rb_entry *entry =
+                       rb_entry(node, struct ceph_subvol_metric_rb_entry, node);
+
+               if (subvol_id < entry->subvolume_id)
+                       node = node->rb_left;
+               else if (subvol_id > entry->subvolume_id)
+                       node = node->rb_right;
+               else
+                       return entry;
+       }
+
+       return NULL;
+}
+
+static struct ceph_subvol_metric_rb_entry *
+__insert_entry(struct ceph_subvolume_metrics_tracker *tracker,
+              struct ceph_subvol_metric_rb_entry *entry)
+{
+       struct rb_node **link = &tracker->tree.rb_root.rb_node;
+       struct rb_node *parent = NULL;
+       bool leftmost = true;
+
+       while (*link) {
+               struct ceph_subvol_metric_rb_entry *cur =
+                       rb_entry(*link, struct ceph_subvol_metric_rb_entry, node);
+
+               parent = *link;
+               if (entry->subvolume_id < cur->subvolume_id)
+                       link = &(*link)->rb_left;
+               else if (entry->subvolume_id > cur->subvolume_id) {
+                       link = &(*link)->rb_right;
+                       leftmost = false;
+               } else
+                       return cur;
+       }
+
+       rb_link_node(&entry->node, parent, link);
+       rb_insert_color_cached(&entry->node, &tracker->tree, leftmost);
+       tracker->nr_entries++;
+       return entry;
+}
+
+static void ceph_subvolume_metrics_clear_locked(
+               struct ceph_subvolume_metrics_tracker *tracker)
+{
+       struct rb_node *node = rb_first_cached(&tracker->tree);
+
+       while (node) {
+               struct ceph_subvol_metric_rb_entry *entry =
+                       rb_entry(node, struct ceph_subvol_metric_rb_entry, node);
+               struct rb_node *next = rb_next(node);
+
+               rb_erase_cached(&entry->node, &tracker->tree);
+               tracker->nr_entries--;
+               kmem_cache_free(ceph_subvol_metric_entry_cachep, entry);
+               node = next;
+       }
+
+       tracker->tree = RB_ROOT_CACHED;
+}
+
+void ceph_subvolume_metrics_destroy(struct ceph_subvolume_metrics_tracker *tracker)
+{
+       spin_lock(&tracker->lock);
+       ceph_subvolume_metrics_clear_locked(tracker);
+       tracker->enabled = false;
+       spin_unlock(&tracker->lock);
+}
+
+void ceph_subvolume_metrics_enable(struct ceph_subvolume_metrics_tracker *tracker,
+                                  bool enable)
+{
+       spin_lock(&tracker->lock);
+       if (enable) {
+               tracker->enabled = true;
+       } else {
+               tracker->enabled = false;
+               ceph_subvolume_metrics_clear_locked(tracker);
+       }
+       spin_unlock(&tracker->lock);
+}
+
+void ceph_subvolume_metrics_record(struct ceph_subvolume_metrics_tracker *tracker,
+                                  u64 subvol_id, bool is_write,
+                                  size_t size, u64 latency_us)
+{
+       struct ceph_subvol_metric_rb_entry *entry, *new_entry = NULL;
+       bool retry = false;
+
+       /* CEPH_SUBVOLUME_ID_NONE (0) means unknown/unset subvolume */
+       if (!READ_ONCE(tracker->enabled) ||
+           subvol_id == CEPH_SUBVOLUME_ID_NONE || !size || !latency_us)
+               return;
+
+       /*
+        * Retry loop for lock-free allocation pattern:
+        * 1. First iteration: lookup under lock, if miss -> drop lock, alloc, retry
+        * 2. Second iteration: lookup again (may have been inserted), insert if still missing
+        * 3. On race (another thread inserted same key): free our alloc, retry
+        * All successful paths exit via return, so retry flag doesn't need reset.
+        */
+       do {
+               spin_lock(&tracker->lock);
+               if (!tracker->enabled) {
+                       spin_unlock(&tracker->lock);
+                       if (new_entry)
+                               kmem_cache_free(ceph_subvol_metric_entry_cachep, new_entry);
+                       return;
+               }
+
+               entry = __lookup_entry(tracker, subvol_id);
+               if (!entry) {
+                       if (!new_entry) {
+                               spin_unlock(&tracker->lock);
+                               new_entry = kmem_cache_zalloc(ceph_subvol_metric_entry_cachep,
+                                                     GFP_NOFS);
+                               if (!new_entry)
+                                       return;
+                               new_entry->subvolume_id = subvol_id;
+                               retry = true;
+                               continue;
+                       }
+                       entry = __insert_entry(tracker, new_entry);
+                       if (entry != new_entry) {
+                               /* raced with another insert */
+                               spin_unlock(&tracker->lock);
+                               kmem_cache_free(ceph_subvol_metric_entry_cachep, new_entry);
+                               new_entry = NULL;
+                               retry = true;
+                               continue;
+                       }
+                       new_entry = NULL;
+               }
+
+               if (is_write) {
+                       entry->write_ops++;
+                       entry->write_bytes += size;
+                       entry->write_latency_us += latency_us;
+                       atomic64_inc(&tracker->total_write_ops);
+                       atomic64_add(size, &tracker->total_write_bytes);
+               } else {
+                       entry->read_ops++;
+                       entry->read_bytes += size;
+                       entry->read_latency_us += latency_us;
+                       atomic64_inc(&tracker->total_read_ops);
+                       atomic64_add(size, &tracker->total_read_bytes);
+               }
+               spin_unlock(&tracker->lock);
+               if (new_entry)
+                       kmem_cache_free(ceph_subvol_metric_entry_cachep, new_entry);
+               return;
+       } while (retry);
+}
+
+int ceph_subvolume_metrics_snapshot(struct ceph_subvolume_metrics_tracker *tracker,
+                                   struct ceph_subvol_metric_snapshot **out,
+                                   u32 *nr, bool consume)
+{
+       struct ceph_subvol_metric_snapshot *snap = NULL;
+       struct rb_node *node;
+       u32 count = 0, idx = 0;
+       int ret = 0;
+
+       *out = NULL;
+       *nr = 0;
+
+       if (!READ_ONCE(tracker->enabled))
+               return 0;
+
+       atomic64_inc(&tracker->snapshot_attempts);
+
+       spin_lock(&tracker->lock);
+       for (node = rb_first_cached(&tracker->tree); node; node = rb_next(node)) {
+               struct ceph_subvol_metric_rb_entry *entry =
+                       rb_entry(node, struct ceph_subvol_metric_rb_entry, node);
+
+               /* Include entries with ANY I/O activity (read OR write) */
+               if (entry->read_ops || entry->write_ops)
+                       count++;
+       }
+       spin_unlock(&tracker->lock);
+
+       if (!count) {
+               atomic64_inc(&tracker->snapshot_empty);
+               return 0;
+       }
+
+       snap = kcalloc(count, sizeof(*snap), GFP_NOFS);
+       if (!snap) {
+               atomic64_inc(&tracker->snapshot_failures);
+               return -ENOMEM;
+       }
+
+       spin_lock(&tracker->lock);
+       node = rb_first_cached(&tracker->tree);
+       while (node) {
+               struct ceph_subvol_metric_rb_entry *entry =
+                       rb_entry(node, struct ceph_subvol_metric_rb_entry, node);
+               struct rb_node *next = rb_next(node);
+
+               /* Skip entries with NO I/O activity at all */
+               if (!entry->read_ops && !entry->write_ops) {
+                       rb_erase_cached(&entry->node, &tracker->tree);
+                       tracker->nr_entries--;
+                       kmem_cache_free(ceph_subvol_metric_entry_cachep, entry);
+                       node = next;
+                       continue;
+               }
+
+               if (idx >= count) {
+                       pr_warn("ceph: subvol metrics snapshot race (idx=%u count=%u)\n",
+                               idx, count);
+                       break;
+               }
+
+               snap[idx].subvolume_id = entry->subvolume_id;
+               snap[idx].read_ops = entry->read_ops;
+               snap[idx].write_ops = entry->write_ops;
+               snap[idx].read_bytes = entry->read_bytes;
+               snap[idx].write_bytes = entry->write_bytes;
+               snap[idx].read_latency_us = entry->read_latency_us;
+               snap[idx].write_latency_us = entry->write_latency_us;
+               idx++;
+
+               if (consume) {
+                       entry->read_ops = 0;
+                       entry->write_ops = 0;
+                       entry->read_bytes = 0;
+                       entry->write_bytes = 0;
+                       entry->read_latency_us = 0;
+                       entry->write_latency_us = 0;
+                       rb_erase_cached(&entry->node, &tracker->tree);
+                       tracker->nr_entries--;
+                       kmem_cache_free(ceph_subvol_metric_entry_cachep, entry);
+               }
+               node = next;
+       }
+       spin_unlock(&tracker->lock);
+
+       if (!idx) {
+               kfree(snap);
+               snap = NULL;
+               ret = 0;
+       } else {
+               *nr = idx;
+               *out = snap;
+       }
+
+       return ret;
+}
+
+void ceph_subvolume_metrics_free_snapshot(struct ceph_subvol_metric_snapshot *snapshot)
+{
+       kfree(snapshot);
+}
+
+/*
+ * Dump subvolume metrics to a seq_file for debugfs.
+ *
+ * Iterates the rb-tree directly under spinlock to avoid allocation.
+ * The lock hold time is minimal since we're only doing seq_printf calls.
+ */
+void ceph_subvolume_metrics_dump(struct ceph_subvolume_metrics_tracker *tracker,
+                                struct seq_file *s)
+{
+       struct rb_node *node;
+       bool found = false;
+
+       spin_lock(&tracker->lock);
+       if (!tracker->enabled) {
+               spin_unlock(&tracker->lock);
+               seq_puts(s, "subvolume metrics disabled\n");
+               return;
+       }
+
+       for (node = rb_first_cached(&tracker->tree); node; node = rb_next(node)) {
+               struct ceph_subvol_metric_rb_entry *entry =
+                       rb_entry(node, struct ceph_subvol_metric_rb_entry, node);
+               u64 avg_rd_lat, avg_wr_lat;
+
+               if (!entry->read_ops && !entry->write_ops)
+                       continue;
+
+               if (!found) {
+                       seq_puts(s, "subvol_id       rd_ops    rd_bytes    rd_avg_lat_us  wr_ops    wr_bytes    wr_avg_lat_us\n");
+                       seq_puts(s, "------------------------------------------------------------------------------------------------\n");
+                       found = true;
+               }
+
+               avg_rd_lat = entry->read_ops ?
+                       div64_u64(entry->read_latency_us, entry->read_ops) : 0;
+               avg_wr_lat = entry->write_ops ?
+                       div64_u64(entry->write_latency_us, entry->write_ops) : 0;
+
+               seq_printf(s, "%-15llu%-10llu%-12llu%-16llu%-10llu%-12llu%-16llu\n",
+                          entry->subvolume_id,
+                          entry->read_ops,
+                          entry->read_bytes,
+                          avg_rd_lat,
+                          entry->write_ops,
+                          entry->write_bytes,
+                          avg_wr_lat);
+       }
+       spin_unlock(&tracker->lock);
+
+       if (!found)
+               seq_puts(s, "(no subvolume metrics collected)\n");
+}
+
+void ceph_subvolume_metrics_record_io(struct ceph_mds_client *mdsc,
+                                     struct ceph_inode_info *ci,
+                                     bool is_write, size_t bytes,
+                                     ktime_t start, ktime_t end)
+{
+       struct ceph_subvolume_metrics_tracker *tracker;
+       u64 subvol_id;
+       s64 delta_us;
+
+       if (!mdsc || !ci || !bytes)
+               return;
+
+       tracker = &mdsc->subvol_metrics;
+       atomic64_inc(&tracker->record_calls);
+
+       if (!ceph_subvolume_metrics_enabled(tracker)) {
+               atomic64_inc(&tracker->record_disabled);
+               return;
+       }
+
+       subvol_id = READ_ONCE(ci->i_subvolume_id);
+       if (subvol_id == CEPH_SUBVOLUME_ID_NONE) {
+               atomic64_inc(&tracker->record_no_subvol);
+               return;
+       }
+
+       delta_us = ktime_to_us(ktime_sub(end, start));
+       if (delta_us <= 0)
+               delta_us = 1;
+
+       ceph_subvolume_metrics_record(tracker, subvol_id, is_write,
+                                     bytes, (u64)delta_us);
+}
+
+int __init ceph_subvolume_metrics_cache_init(void)
+{
+       ceph_subvol_metric_entry_cachep = KMEM_CACHE(ceph_subvol_metric_rb_entry,
+                                                   SLAB_RECLAIM_ACCOUNT);
+       if (!ceph_subvol_metric_entry_cachep)
+               return -ENOMEM;
+       return 0;
+}
+
+void ceph_subvolume_metrics_cache_destroy(void)
+{
+       kmem_cache_destroy(ceph_subvol_metric_entry_cachep);
+}
diff --git a/fs/ceph/subvolume_metrics.h b/fs/ceph/subvolume_metrics.h
new file mode 100644 (file)
index 0000000..6f53ff7
--- /dev/null
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _FS_CEPH_SUBVOLUME_METRICS_H
+#define _FS_CEPH_SUBVOLUME_METRICS_H
+
+#include <linux/types.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/ktime.h>
+#include <linux/atomic.h>
+
+struct seq_file;
+struct ceph_mds_client;
+struct ceph_inode_info;
+
+/**
+ * struct ceph_subvol_metric_snapshot - Point-in-time snapshot of subvolume metrics
+ * @subvolume_id: Subvolume identifier (inode number of subvolume root)
+ * @read_ops: Number of read operations since last snapshot
+ * @write_ops: Number of write operations since last snapshot
+ * @read_bytes: Total bytes read since last snapshot
+ * @write_bytes: Total bytes written since last snapshot
+ * @read_latency_us: Sum of read latencies in microseconds (for avg calculation)
+ * @write_latency_us: Sum of write latencies in microseconds (for avg calculation)
+ */
+struct ceph_subvol_metric_snapshot {
+       u64 subvolume_id;
+       u64 read_ops;
+       u64 write_ops;
+       u64 read_bytes;
+       u64 write_bytes;
+       u64 read_latency_us;
+       u64 write_latency_us;
+};
+
+/**
+ * struct ceph_subvolume_metrics_tracker - Tracks per-subvolume I/O metrics
+ * @lock: Protects @tree and @nr_entries during concurrent access
+ * @tree: Red-black tree of per-subvolume entries, keyed by subvolume_id
+ * @nr_entries: Number of entries currently in @tree
+ * @enabled: Whether collection is enabled (requires MDS feature support)
+ * @snapshot_attempts: Debug counter: total ceph_subvolume_metrics_snapshot() calls
+ * @snapshot_empty: Debug counter: snapshots that found no data to report
+ * @snapshot_failures: Debug counter: snapshots that failed to allocate memory
+ * @record_calls: Debug counter: total ceph_subvolume_metrics_record() calls
+ * @record_disabled: Debug counter: record calls skipped because disabled
+ * @record_no_subvol: Debug counter: record calls skipped (no subvolume_id)
+ * @total_read_ops: Cumulative read ops across all snapshots (never reset)
+ * @total_read_bytes: Cumulative bytes read across all snapshots (never reset)
+ * @total_write_ops: Cumulative write ops across all snapshots (never reset)
+ * @total_write_bytes: Cumulative bytes written across all snapshots (never reset)
+ */
+struct ceph_subvolume_metrics_tracker {
+       spinlock_t lock;
+       struct rb_root_cached tree;
+       u32 nr_entries;
+       bool enabled;
+       atomic64_t snapshot_attempts;
+       atomic64_t snapshot_empty;
+       atomic64_t snapshot_failures;
+       atomic64_t record_calls;
+       atomic64_t record_disabled;
+       atomic64_t record_no_subvol;
+       atomic64_t total_read_ops;
+       atomic64_t total_read_bytes;
+       atomic64_t total_write_ops;
+       atomic64_t total_write_bytes;
+};
+
+void ceph_subvolume_metrics_init(struct ceph_subvolume_metrics_tracker *tracker);
+void ceph_subvolume_metrics_destroy(struct ceph_subvolume_metrics_tracker *tracker);
+void ceph_subvolume_metrics_enable(struct ceph_subvolume_metrics_tracker *tracker,
+                                  bool enable);
+void ceph_subvolume_metrics_record(struct ceph_subvolume_metrics_tracker *tracker,
+                                  u64 subvol_id, bool is_write,
+                                  size_t size, u64 latency_us);
+int ceph_subvolume_metrics_snapshot(struct ceph_subvolume_metrics_tracker *tracker,
+                                   struct ceph_subvol_metric_snapshot **out,
+                                   u32 *nr, bool consume);
+void ceph_subvolume_metrics_free_snapshot(struct ceph_subvol_metric_snapshot *snapshot);
+void ceph_subvolume_metrics_dump(struct ceph_subvolume_metrics_tracker *tracker,
+                                struct seq_file *s);
+
+void ceph_subvolume_metrics_record_io(struct ceph_mds_client *mdsc,
+                                     struct ceph_inode_info *ci,
+                                     bool is_write, size_t bytes,
+                                     ktime_t start, ktime_t end);
+
+static inline bool ceph_subvolume_metrics_enabled(
+               const struct ceph_subvolume_metrics_tracker *tracker)
+{
+       return READ_ONCE(tracker->enabled);
+}
+
+int __init ceph_subvolume_metrics_cache_init(void);
+void ceph_subvolume_metrics_cache_destroy(void);
+
+#endif /* _FS_CEPH_SUBVOLUME_METRICS_H */
index 2aed6b3359b642e2d9da0204c3f398ae18bb1464..c05fbd4237f86f99aa9699416f5f018b176c4ba2 100644 (file)
@@ -21,6 +21,7 @@
 #include "mds_client.h"
 #include "cache.h"
 #include "crypto.h"
+#include "subvolume_metrics.h"
 
 #include <linux/ceph/ceph_features.h>
 #include <linux/ceph/decode.h>
@@ -966,8 +967,14 @@ static int __init init_caches(void)
        if (!ceph_wb_pagevec_pool)
                goto bad_pagevec_pool;
 
+       error = ceph_subvolume_metrics_cache_init();
+       if (error)
+               goto bad_subvol_metrics;
+
        return 0;
 
+bad_subvol_metrics:
+       mempool_destroy(ceph_wb_pagevec_pool);
 bad_pagevec_pool:
        kmem_cache_destroy(ceph_mds_request_cachep);
 bad_mds_req:
@@ -1004,6 +1011,7 @@ static void destroy_caches(void)
        kmem_cache_destroy(ceph_dir_file_cachep);
        kmem_cache_destroy(ceph_mds_request_cachep);
        mempool_destroy(ceph_wb_pagevec_pool);
+       ceph_subvolume_metrics_cache_destroy();
 }
 
 static void __ceph_umount_begin(struct ceph_fs_client *fsc)
index cd5f7106126411ba7ee4f1f6dd185350cd133be3..afc89ce91804eddc31c2e3371cde8a8645cea0f2 100644 (file)
@@ -179,6 +179,7 @@ struct ceph_fs_client {
        struct dentry *debugfs_status;
        struct dentry *debugfs_mds_sessions;
        struct dentry *debugfs_metrics_dir;
+       struct dentry *debugfs_subvolume_metrics;
 #endif
 
 #ifdef CONFIG_CEPH_FSCACHE