afs: Improve afs_volume tracing to display a debug ID

Improve the tracing of afs_volume objects to include displaying a debug ID
so that different instances of volumes with the same "vid" can be
distinguished.

Also be consistent about displaying the volume's refcount (and not the
cell's).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20250224234154.2014840-9-dhowells@redhat.com/
Link: https://lore.kernel.org/r/20250310094206.801057-5-dhowells@redhat.com/

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 47e98a78f59f3b37dd512154818d6ba997deaffd..97045e2a455decf36c94d85cb5236a4c50d5dd1c 100644 (file)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -623,6 +623,7 @@ struct afs_volume {
        afs_volid_t             vid;            /* The volume ID of this volume */
        afs_volid_t             vids[AFS_MAXTYPES]; /* All associated volume IDs */
        refcount_t              ref;
+       unsigned int            debug_id;       /* Debugging ID for traces */
        time64_t                update_at;      /* Time at which to next update */
        struct afs_cell         *cell;          /* Cell to which belongs (pins ref) */
        struct rb_node          cell_node;      /* Link in cell->volumes */

diff --git a/fs/afs/volume.c b/fs/afs/volume.c
index af3a3f57c1b3f9512bcaa08ce37a0f8173e809d0..0efff3d251333e649dbc2d28a2a3abef22d2cc5e 100644 (file)
--- a/fs/afs/volume.c
+++ b/fs/afs/volume.c
@@ -10,6 +10,7 @@
 #include "internal.h"
 
 static unsigned __read_mostly afs_volume_record_life = 60 * 60;
+static atomic_t afs_volume_debug_id;
 
 static void afs_destroy_volume(struct work_struct *work);
 
@@ -59,7 +60,7 @@ static void afs_remove_volume_from_cell(struct afs_volume *volume)
        struct afs_cell *cell = volume->cell;
 
        if (!hlist_unhashed(&volume->proc_link)) {
-               trace_afs_volume(volume->vid, refcount_read(&cell->ref),
+               trace_afs_volume(volume->debug_id, volume->vid, refcount_read(&volume->ref),
                                 afs_volume_trace_remove);
                write_seqlock(&cell->volume_lock);
                hlist_del_rcu(&volume->proc_link);
@@ -84,6 +85,7 @@ static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params,
        if (!volume)
                goto error_0;
 
+       volume->debug_id        = atomic_inc_return(&afs_volume_debug_id);
        volume->vid             = vldb->vid[params->type];
        volume->update_at       = ktime_get_real_seconds() + afs_volume_record_life;
        volume->cell            = afs_get_cell(params->cell, afs_cell_trace_get_vol);
@@ -115,7 +117,7 @@ static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params,
 
        *_slist = slist;
        rcu_assign_pointer(volume->servers, slist);
-       trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);
+       trace_afs_volume(volume->debug_id, volume->vid, 1, afs_volume_trace_alloc);
        return volume;
 
 error_1:
@@ -247,7 +249,7 @@ static void afs_destroy_volume(struct work_struct *work)
        afs_remove_volume_from_cell(volume);
        afs_put_serverlist(volume->cell->net, slist);
        afs_put_cell(volume->cell, afs_cell_trace_put_vol);
-       trace_afs_volume(volume->vid, refcount_read(&volume->ref),
+       trace_afs_volume(volume->debug_id, volume->vid, refcount_read(&volume->ref),
                         afs_volume_trace_free);
        kfree_rcu(volume, rcu);
 
@@ -262,7 +264,7 @@ bool afs_try_get_volume(struct afs_volume *volume, enum afs_volume_trace reason)
        int r;
 
        if (__refcount_inc_not_zero(&volume->ref, &r)) {
-               trace_afs_volume(volume->vid, r + 1, reason);
+               trace_afs_volume(volume->debug_id, volume->vid, r + 1, reason);
                return true;
        }
        return false;
@@ -278,7 +280,7 @@ struct afs_volume *afs_get_volume(struct afs_volume *volume,
                int r;
 
                __refcount_inc(&volume->ref, &r);
-               trace_afs_volume(volume->vid, r + 1, reason);
+               trace_afs_volume(volume->debug_id, volume->vid, r + 1, reason);
        }
        return volume;
 }
@@ -290,12 +292,13 @@ struct afs_volume *afs_get_volume(struct afs_volume *volume,
 void afs_put_volume(struct afs_volume *volume, enum afs_volume_trace reason)
 {
        if (volume) {
+               unsigned int debug_id = volume->debug_id;
                afs_volid_t vid = volume->vid;
                bool zero;
                int r;
 
                zero = __refcount_dec_and_test(&volume->ref, &r);
-               trace_afs_volume(vid, r - 1, reason);
+               trace_afs_volume(debug_id, vid, r - 1, reason);
                if (zero)
                        schedule_work(&volume->destructor);
        }

diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h
index c19132605f410a3d5fda48039b019b7401b23b0e..cf94bf1e8286dad1e2637d0919a85c4056d60967 100644 (file)
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -1539,25 +1539,29 @@ TRACE_EVENT(afs_server,
            );
 
 TRACE_EVENT(afs_volume,
-           TP_PROTO(afs_volid_t vid, int ref, enum afs_volume_trace reason),
+           TP_PROTO(unsigned int debug_id, afs_volid_t vid, int ref,
+                    enum afs_volume_trace reason),
 
-           TP_ARGS(vid, ref, reason),
+           TP_ARGS(debug_id, vid, ref, reason),
 
            TP_STRUCT__entry(
+                   __field(unsigned int,               debug_id)
                    __field(afs_volid_t,                vid)
                    __field(int,                        ref)
                    __field(enum afs_volume_trace,      reason)
                             ),
 
            TP_fast_assign(
-                   __entry->vid = vid;
-                   __entry->ref = ref;
-                   __entry->reason = reason;
+                   __entry->debug_id   = debug_id;
+                   __entry->vid        = vid;
+                   __entry->ref        = ref;
+                   __entry->reason     = reason;
                           ),
 
-           TP_printk("V=%llx %s ur=%d",
-                     __entry->vid,
+           TP_printk("V=%08x %s vid=%llx r=%d",
+                     __entry->debug_id,
                      __print_symbolic(__entry->reason, afs_volume_traces),
+                     __entry->vid,
                      __entry->ref)
            );