[for-linus][PATCH 0/2] tracing: A couple of updates for 6.8

[for-linus][PATCH 0/2] tracing: A couple of updates for 6.8

[Steven Rostedt]

tracing: Two small fixes for tracefs and eventfs:

- Fix register_snapshot_trigger() on allocation error
  If the snashot fails to allocate, the register_snapshot_trigger() can
  still return success. If the call to tracing_alloc_snapshot_instance()
  returned anything but 0, it returned 0, but it should have been returing
  the error code from that allocation function.

- Remove leftover code from tracefs doing a dentry walk on remount.
  The update_gid() function was called by the tracefs code on remount
  to update the gid of eventfs, but that is no longer the case, but that
  code wasn't deleted. Nothing calls it. Remove it.

  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace/urgent

Head SHA1: 29142dc92c37d3259a33aef15b03e6ee25b0d188


Linus Torvalds (1):
      tracefs: remove stale 'update_gid' code

Masami Hiramatsu (Google) (1):
      tracing/trigger: Fix to return error if failed to alloc snapshot

----
 fs/tracefs/event_inode.c            | 38 -------------------------------------
 fs/tracefs/internal.h               |  1 -
 kernel/trace/trace_events_trigger.c |  6 ++++--
 3 files changed, 4 insertions(+), 41 deletions(-)

[for-linus][PATCH 1/2] tracing/trigger: Fix to return error if failed to alloc snapshot

[Steven Rostedt]

From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>

Fix register_snapshot_trigger() to return error code if it failed to
allocate a snapshot instead of 0 (success). Unless that, it will register
snapshot trigger without an error.

Link: https://lore.kernel.org/linux-trace-kernel/170622977792.270660.2789298642759362200.stgit@devnote2

Fixes: 0bbe7f719985 ("tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation")
Cc: stable@vger.kernel.org
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_trigger.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 46439e3bcec4..b33c3861fbbb 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -1470,8 +1470,10 @@ register_snapshot_trigger(char *glob,
 			  struct event_trigger_data *data,
 			  struct trace_event_file *file)
 {
-	if (tracing_alloc_snapshot_instance(file->tr) != 0)
-		return 0;
+	int ret = tracing_alloc_snapshot_instance(file->tr);
+
+	if (ret < 0)
+		return ret;
 
 	return register_trigger(glob, data, file);
 }
-- 
2.43.0

[for-linus][PATCH 2/2] tracefs: remove stale update_gid code

[Steven Rostedt]

From: Linus Torvalds <torvalds@linux-foundation.org>

The 'eventfs_update_gid()' function is no longer called, so remove it
(and the helper function it uses).

Link: https://lore.kernel.org/all/CAHk-=wj+DsZZ=2iTUkJ-Nojs9fjYMvPs1NuoM3yK7aTDtJfPYQ@mail.gmail.com/

Fixes: 8186fff7ab64 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 fs/tracefs/event_inode.c | 38 --------------------------------------
 fs/tracefs/internal.h    |  1 -
 2 files changed, 39 deletions(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 6b211522a13e..1c3dd0ad4660 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -281,44 +281,6 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
 		inode->i_gid = attr->gid;
 }
 
-static void update_gid(struct eventfs_inode *ei, kgid_t gid, int level)
-{
-	struct eventfs_inode *ei_child;
-
-	/* at most we have events/system/event */
-	if (WARN_ON_ONCE(level > 3))
-		return;
-
-	ei->attr.gid = gid;
-
-	if (ei->entry_attrs) {
-		for (int i = 0; i < ei->nr_entries; i++) {
-			ei->entry_attrs[i].gid = gid;
-		}
-	}
-
-	/*
-	 * Only eventfs_inode with dentries are updated, make sure
-	 * all eventfs_inodes are updated. If one of the children
-	 * do not have a dentry, this function must traverse it.
-	 */
-	list_for_each_entry_srcu(ei_child, &ei->children, list,
-				 srcu_read_lock_held(&eventfs_srcu)) {
-		if (!ei_child->dentry)
-			update_gid(ei_child, gid, level + 1);
-	}
-}
-
-void eventfs_update_gid(struct dentry *dentry, kgid_t gid)
-{
-	struct eventfs_inode *ei = dentry->d_fsdata;
-	int idx;
-
-	idx = srcu_read_lock(&eventfs_srcu);
-	update_gid(ei, gid, 0);
-	srcu_read_unlock(&eventfs_srcu, idx);
-}
-
 /**
  * create_file - create a file in the tracefs filesystem
  * @name: the name of the file to create.
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 45397df9bb65..91c2bf0b91d9 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -82,7 +82,6 @@ struct inode *tracefs_get_inode(struct super_block *sb);
 struct dentry *eventfs_start_creating(const char *name, struct dentry *parent);
 struct dentry *eventfs_failed_creating(struct dentry *dentry);
 struct dentry *eventfs_end_creating(struct dentry *dentry);
-void eventfs_update_gid(struct dentry *dentry, kgid_t gid);
 void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
 
 #endif /* _TRACEFS_INTERNAL_H */
-- 
2.43.0