afs: Make afs_lookup_cell() take a trace note

Pass a note to be added to the afs_cell tracepoint to afs_lookup_cell() so
that different callers can be distinguished.

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/20250224234154.2014840-11-dhowells@redhat.com/ # v1
Link: https://lore.kernel.org/r/20250310094206.801057-7-dhowells@redhat.com/ # v4

fs/afs/cell.c

@@ -233,6 +233,7 @@ error:
  * @namesz:	The strlen of the cell name.
  * @vllist:	A colon/comma separated list of numeric IP addresses or NULL.
  * @excl:	T if an error should be given if the cell name already exists.
+ * @trace:	The reason to be logged if the lookup is successful.
  *
  * Look up a cell record by name and query the DNS for VL server addresses if
  * needed.  Note that that actual DNS query is punted off to the manager thread
@@ -241,7 +242,8 @@ error:
  */
 struct afs_cell *afs_lookup_cell(struct afs_net *net,
 				 const char *name, unsigned int namesz,
-				 const char *vllist, bool excl)
+				 const char *vllist, bool excl,
+				 enum afs_cell_trace trace)
 {
 	struct afs_cell *cell, *candidate, *cursor;
 	struct rb_node *parent, **pp;
@@ -251,7 +253,7 @@ struct afs_cell *afs_lookup_cell(struct afs_net *net,
 	_enter("%s,%s", name, vllist);
 
 	if (!excl) {
-		cell = afs_find_cell(net, name, namesz, afs_cell_trace_use_lookup);
+		cell = afs_find_cell(net, name, namesz, trace);
 		if (!IS_ERR(cell))
 			goto wait_for_cell;
 	}
@@ -327,7 +329,7 @@ cell_already_exists:
 	if (excl) {
 		ret = -EEXIST;
 	} else {
-		afs_use_cell(cursor, afs_cell_trace_use_lookup);
+		afs_use_cell(cursor, trace);
 		ret = 0;
 	}
 	up_write(&net->cells_lock);
@@ -382,8 +384,9 @@ int afs_cell_init(struct afs_net *net, const char *rootcell)
 	if (cp && cp < rootcell + len)
 		return -EINVAL;
 
-	/* allocate a cell record for the root cell */
-	new_root = afs_lookup_cell(net, rootcell, len, vllist, false);
+	/* allocate a cell record for the root/workstation cell */
+	new_root = afs_lookup_cell(net, rootcell, len, vllist, false,
+				   afs_cell_trace_use_lookup_ws);
 	if (IS_ERR(new_root)) {
 		_leave(" = %ld", PTR_ERR(new_root));
 		return PTR_ERR(new_root);

fs/afs/dynroot.c

@@ -108,7 +108,8 @@ static struct dentry *afs_dynroot_lookup_cell(struct inode *dir, struct dentry *
 		dotted = true;
 	}
 
-	cell = afs_lookup_cell(net, name, len, NULL, false);
+	cell = afs_lookup_cell(net, name, len, NULL, false,
+			       afs_cell_trace_use_lookup_dynroot);
 	if (IS_ERR(cell)) {
 		ret = PTR_ERR(cell);
 		goto out_no_cell;

fs/afs/internal.h

@@ -1046,8 +1046,10 @@ static inline bool afs_cb_is_broken(unsigned int cb_break,
 extern int afs_cell_init(struct afs_net *, const char *);
 extern struct afs_cell *afs_find_cell(struct afs_net *, const char *, unsigned,
 				      enum afs_cell_trace);
-extern struct afs_cell *afs_lookup_cell(struct afs_net *, const char *, unsigned,
-					const char *, bool);
+struct afs_cell *afs_lookup_cell(struct afs_net *net,
+				 const char *name, unsigned int namesz,
+				 const char *vllist, bool excl,
+				 enum afs_cell_trace trace);
 extern struct afs_cell *afs_use_cell(struct afs_cell *, enum afs_cell_trace);
 extern void afs_unuse_cell(struct afs_net *, struct afs_cell *, enum afs_cell_trace);
 extern struct afs_cell *afs_get_cell(struct afs_cell *, enum afs_cell_trace);

fs/afs/mntpt.c

@@ -107,7 +107,8 @@ static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
 		if (size > AFS_MAXCELLNAME)
 			return -ENAMETOOLONG;
 
-		cell = afs_lookup_cell(ctx->net, p, size, NULL, false);
+		cell = afs_lookup_cell(ctx->net, p, size, NULL, false,
+				       afs_cell_trace_use_lookup_mntpt);
 		if (IS_ERR(cell)) {
 			pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt);
 			return PTR_ERR(cell);

fs/afs/proc.c

@@ -122,7 +122,8 @@ static int afs_proc_cells_write(struct file *file, char *buf, size_t size)
 	if (strcmp(buf, "add") == 0) {
 		struct afs_cell *cell;
 
-		cell = afs_lookup_cell(net, name, strlen(name), args, true);
+		cell = afs_lookup_cell(net, name, strlen(name), args, true,
+				       afs_cell_trace_use_lookup_add);
 		if (IS_ERR(cell)) {
 			ret = PTR_ERR(cell);
 			goto done;

fs/afs/super.c

@@ -290,7 +290,8 @@ static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
 	/* lookup the cell record */
 	if (cellname) {
 		cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
-				       NULL, false);
+				       NULL, false,
+				       afs_cell_trace_use_lookup_mount);
 		if (IS_ERR(cell)) {
 			pr_err("kAFS: unable to lookup cell '%*.*s'\n",
 			       cellnamesz, cellnamesz, cellname ?: "");

fs/afs/vl_alias.c

@@ -269,7 +269,8 @@ static int yfs_check_canonical_cell_name(struct afs_cell *cell, struct key *key)
 	if (!name_len || name_len > AFS_MAXCELLNAME)
 		master = ERR_PTR(-EOPNOTSUPP);
 	else
-		master = afs_lookup_cell(cell->net, cell_name, name_len, NULL, false);
+		master = afs_lookup_cell(cell->net, cell_name, name_len, NULL, false,
+					 afs_cell_trace_use_lookup_canonical);
 	kfree(cell_name);
 	if (IS_ERR(master))
 		return PTR_ERR(master);

include/trace/events/afs.h

@@ -208,7 +208,12 @@ enum yfs_cm_operation {
 	EM(afs_cell_trace_use_check_alias,	"USE chk-al") \
 	EM(afs_cell_trace_use_fc,		"USE fc    ") \
 	EM(afs_cell_trace_use_fc_alias,		"USE fc-al ") \
-	EM(afs_cell_trace_use_lookup,		"USE lookup") \
+	EM(afs_cell_trace_use_lookup_add,	"USE lu-add") \
+	EM(afs_cell_trace_use_lookup_canonical,	"USE lu-can") \
+	EM(afs_cell_trace_use_lookup_dynroot,	"USE lu-dyn") \
+	EM(afs_cell_trace_use_lookup_mntpt,	"USE lu-mpt") \
+	EM(afs_cell_trace_use_lookup_mount,	"USE lu-mnt") \
+	EM(afs_cell_trace_use_lookup_ws,	"USE lu-ws ") \
 	EM(afs_cell_trace_use_mntpt,		"USE mntpt ") \
 	EM(afs_cell_trace_use_pin,		"USE pin   ") \
 	EM(afs_cell_trace_use_probe,		"USE probe ") \