DLPX-83701 Make function mnt_add_count() traceable (#16)

Don Brady · Delphix Engineering · commit 539f5b78e697 · 2025-05-10T05:19:38.000Z
diff --git a/fs/namespace.c b/fs/namespace.c
@@ -275,7 +275,7 @@ void mnt_release_group_id(struct mount *mnt)
 /*
  * vfsmount lock must be held for read
  */
-static inline void mnt_add_count(struct mount *mnt, int n)
+static noinline __noclone void mnt_add_count(struct mount *mnt, int n)
 {
 #ifdef CONFIG_SMP
 	this_cpu_add(mnt->mnt_pcp->mnt_count, n);
@@ -1834,7 +1834,8 @@ static int do_umount_root(struct super_block *sb)
 	return ret;
 }
 
-static int do_umount(struct mount *mnt, int flags)
+/* force a bpftrace dynamic function probe here */
+static noinline __noclone int do_umount(struct mount *mnt, int flags)
 {
 	struct super_block *sb = mnt->mnt.mnt_sb;
 	int retval;

Original file line number	Diff line number	Diff line change
`@@ -275,7 +275,7 @@ void mnt_release_group_id(struct mount *mnt)`
`275`	`275`	`/*`
`276`	`276`	`* vfsmount lock must be held for read`
`277`	`277`	`*/`
`278`		`-static inline void mnt_add_count(struct mount *mnt, int n)`
	`278`	`+static noinline __noclone void mnt_add_count(struct mount *mnt, int n)`
`279`	`279`	`{`
`280`	`280`	`#ifdef CONFIG_SMP`
`281`	`281`	`this_cpu_add(mnt->mnt_pcp->mnt_count, n);`
`@@ -1834,7 +1834,8 @@ static int do_umount_root(struct super_block *sb)`
`1834`	`1834`	`return ret;`
`1835`	`1835`	`}`
`1836`	`1836`
`1837`		`-static int do_umount(struct mount *mnt, int flags)`
	`1837`	`+/* force a bpftrace dynamic function probe here */`
	`1838`	`+static noinline __noclone int do_umount(struct mount *mnt, int flags)`
`1838`	`1839`	`{`
`1839`	`1840`	`struct super_block *sb = mnt->mnt.mnt_sb;`
`1840`	`1841`	`int retval;`