3 files changed, 102 insertions, 6 deletions

diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
index 8704372ac38f..238925c1aafd 100644
--- a/fs/nfs/nfs4trace.h
+++ b/fs/nfs/nfs4trace.h
@@ -1442,6 +1442,62 @@ DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_layoutcommit);
 DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_layoutreturn);
 DEFINE_NFS4_INODE_EVENT(nfs4_layoutreturn_on_close);
 
+#define show_pnfs_update_layout_reason(reason)                          \
+        __print_symbolic(reason,                                        \
+                { PNFS_UPDATE_LAYOUT_UNKNOWN, "unknown" },              \
+                { PNFS_UPDATE_LAYOUT_NO_PNFS, "no pnfs" },              \
+                { PNFS_UPDATE_LAYOUT_RD_ZEROLEN, "read+zerolen" },      \
+                { PNFS_UPDATE_LAYOUT_MDSTHRESH, "mdsthresh" },          \
+                { PNFS_UPDATE_LAYOUT_NOMEM, "nomem" },                  \
+                { PNFS_UPDATE_LAYOUT_BULK_RECALL, "bulk recall" },      \
+                { PNFS_UPDATE_LAYOUT_IO_TEST_FAIL, "io test fail" },    \
+                { PNFS_UPDATE_LAYOUT_FOUND_CACHED, "found cached" },    \
+                { PNFS_UPDATE_LAYOUT_RETURN, "layoutreturn" },          \
+                { PNFS_UPDATE_LAYOUT_BLOCKED, "layouts blocked" },      \
+                { PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET, "sent layoutget" })
+
+TRACE_EVENT(pnfs_update_layout,
+                TP_PROTO(struct inode *inode,
+                        loff_t pos,
+                        u64 count,
+                        enum pnfs_iomode iomode,
+                        struct pnfs_layout_segment *lseg,
+                        enum pnfs_update_layout_reason reason
+                ),
+                TP_ARGS(inode, pos, count, iomode, lseg, reason),
+                TP_STRUCT__entry(
+                        __field(dev_t, dev)
+                        __field(u64, fileid)
+                        __field(u32, fhandle)
+                        __field(loff_t, pos)
+                        __field(u64, count)
+                        __field(enum pnfs_iomode, iomode)
+                        __field(struct pnfs_layout_segment *, lseg)
+                        __field(enum pnfs_update_layout_reason, reason)
+                ),
+                TP_fast_assign(
+                        __entry->dev = inode->i_sb->s_dev;
+                        __entry->fileid = NFS_FILEID(inode);
+                        __entry->fhandle = nfs_fhandle_hash(NFS_FH(inode));
+                        __entry->pos = pos;
+                        __entry->count = count;
+                        __entry->iomode = iomode;
+                        __entry->lseg = lseg;
+                        __entry->reason = reason;
+                ),
+                TP_printk(
+                        "fileid=%02x:%02x:%llu fhandle=0x%08x "
+                        "iomode=%s pos=%llu count=%llu lseg=%p (%s)",
+                        MAJOR(__entry->dev), MINOR(__entry->dev),
+                        (unsigned long long)__entry->fileid,
+                        __entry->fhandle,
+                        show_pnfs_iomode(__entry->iomode),
+                        (unsigned long long)__entry->pos,
+                        (unsigned long long)__entry->count, __entry->lseg,
+                        show_pnfs_update_layout_reason(__entry->reason)
+                )
+);
+
 #endif /* CONFIG_NFS_V4_1 */
 
 #endif /* _TRACE_NFS4_H */
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index bec0384499f7..1489065bb051 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1520,14 +1520,23 @@ pnfs_update_layout(struct inode *ino,
         struct pnfs_layout_segment *lseg = NULL;
         bool first;
 
-        if (!pnfs_enabled_sb(NFS_SERVER(ino)))
+        if (!pnfs_enabled_sb(NFS_SERVER(ino))) {
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                 PNFS_UPDATE_LAYOUT_NO_PNFS);
                 goto out;
+        }
 
-        if (iomode == IOMODE_READ && i_size_read(ino) == 0)
+        if (iomode == IOMODE_READ && i_size_read(ino) == 0) {
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                 PNFS_UPDATE_LAYOUT_RD_ZEROLEN);
                 goto out;
+        }
 
-        if (pnfs_within_mdsthreshold(ctx, ino, iomode))
+        if (pnfs_within_mdsthreshold(ctx, ino, iomode)) {
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                 PNFS_UPDATE_LAYOUT_MDSTHRESH);
                 goto out;
+        }
 
 lookup_again:
         first = false;
@@ -1535,19 +1544,26 @@ lookup_again:
         lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
         if (lo == NULL) {
                 spin_unlock(&ino->i_lock);
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                 PNFS_UPDATE_LAYOUT_NOMEM);
                 goto out;
         }
 
         /* Do we even need to bother with this? */
         if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                 PNFS_UPDATE_LAYOUT_BULK_RECALL);
                 dprintk("%s matches recall, use MDS\n", __func__);
                 goto out_unlock;
         }
 
         /* if LAYOUTGET already failed once we don't try again */
         if (pnfs_layout_io_test_failed(lo, iomode) &&
-            !pnfs_should_retry_layoutget(lo))
+            !pnfs_should_retry_layoutget(lo)) {
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                 PNFS_UPDATE_LAYOUT_IO_TEST_FAIL);
                 goto out_unlock;
+        }
 
         first = list_empty(&lo->plh_segs);
         if (first) {
@@ -1567,8 +1583,11 @@ lookup_again:
                  * already exists
                  */
                 lseg = pnfs_find_lseg(lo, &arg);
-                if (lseg)
+                if (lseg) {
+                        trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                        PNFS_UPDATE_LAYOUT_FOUND_CACHED);
                         goto out_unlock;
+                }
         }
 
         /*
@@ -1585,11 +1604,16 @@ lookup_again:
                         dprintk("%s retrying\n", __func__);
                         goto lookup_again;
                 }
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                PNFS_UPDATE_LAYOUT_RETURN);
                 goto out_put_layout_hdr;
         }
 
-        if (pnfs_layoutgets_blocked(lo))
+        if (pnfs_layoutgets_blocked(lo)) {
+                trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                PNFS_UPDATE_LAYOUT_BLOCKED);
                 goto out_unlock;
+        }
         atomic_inc(&lo->plh_outstanding);
         spin_unlock(&ino->i_lock);
 
@@ -1614,6 +1638,8 @@ lookup_again:
         lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
         pnfs_clear_retry_layoutget(lo);
         atomic_dec(&lo->plh_outstanding);
+        trace_pnfs_update_layout(ino, pos, count, iomode, lseg,
+                                 PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);
 out_put_layout_hdr:
         if (first)
                 pnfs_clear_first_layoutget(lo);
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index e7e78537aea2..0e30f2c5ff49 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -592,4 +592,18 @@ enum data_content4 {
         NFS4_CONTENT_HOLE               = 1,
 };
 
+enum pnfs_update_layout_reason {
+        PNFS_UPDATE_LAYOUT_UNKNOWN = 0,
+        PNFS_UPDATE_LAYOUT_NO_PNFS,
+        PNFS_UPDATE_LAYOUT_RD_ZEROLEN,
+        PNFS_UPDATE_LAYOUT_MDSTHRESH,
+        PNFS_UPDATE_LAYOUT_NOMEM,
+        PNFS_UPDATE_LAYOUT_BULK_RECALL,
+        PNFS_UPDATE_LAYOUT_IO_TEST_FAIL,
+        PNFS_UPDATE_LAYOUT_FOUND_CACHED,
+        PNFS_UPDATE_LAYOUT_RETURN,
+        PNFS_UPDATE_LAYOUT_BLOCKED,
+        PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET,
+};
+
 #endif