This is a note to let you know that I've just added the patch titled
Revert "eventfs: Use simple_recursive_removal() to clean up dentries"
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-eventfs-use-simple_recursive_removal-to-clean-up-dentries.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From SRS0=eEWY=JP=rostedt.homelinux.com=rostedt@xxxxxxxxxx Tue Feb 6 13:09:19 2024
From: Steven Rostedt <rostedt@xxxxxxxxxxx>
Date: Tue, 06 Feb 2024 07:09:08 -0500
Subject: Revert "eventfs: Use simple_recursive_removal() to clean up dentries"
To: linux-kernel@xxxxxxxxxxxxxxx, stable@xxxxxxxxxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>, Masami Hiramatsu <mhiramat@xxxxxxxxxx>, Mark Rutland <mark.rutland@xxxxxxx>, Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Message-ID: <20240206120946.866568635@xxxxxxxxxxxxxxxxxxxxx>
From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
This reverts commit 055907ad2c14838c90d63297f7bab8d180a5d844.
The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/tracefs/event_inode.c | 71 +++++++++++++++++++++++++----------------------
1 file changed, 38 insertions(+), 33 deletions(-)
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -54,10 +54,12 @@ struct eventfs_file {
/*
* Union - used for deletion
* @llist: for calling dput() if needed after RCU
+ * @del_list: list of eventfs_file to delete
* @rcu: eventfs_file to delete in RCU
*/
union {
struct llist_node llist;
+ struct list_head del_list;
struct rcu_head rcu;
};
void *data;
@@ -274,6 +276,7 @@ static void free_ef(struct eventfs_file
*/
void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
{
+ struct tracefs_inode *ti_parent;
struct eventfs_inode *ei;
struct eventfs_file *ef;
@@ -294,6 +297,10 @@ void eventfs_set_ef_status_free(struct t
mutex_lock(&eventfs_mutex);
+ ti_parent = get_tracefs(dentry->d_parent->d_inode);
+ if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE))
+ goto out;
+
ef = dentry->d_fsdata;
if (!ef)
goto out;
@@ -866,29 +873,30 @@ static void unhook_dentry(struct dentry
{
if (!dentry)
return;
- /*
- * Need to add a reference to the dentry that is expected by
- * simple_recursive_removal(), which will include a dput().
- */
- dget(dentry);
- /*
- * Also add a reference for the dput() in eventfs_workfn().
- * That is required as that dput() will free the ei after
- * the SRCU grace period is over.
- */
+ /* Keep the dentry from being freed yet (see eventfs_workfn()) */
dget(dentry);
+
+ dentry->d_fsdata = NULL;
+ d_invalidate(dentry);
+ mutex_lock(&eventfs_mutex);
+ /* dentry should now have at least a single reference */
+ WARN_ONCE((int)d_count(dentry) < 1,
+ "dentry %px (%s) less than one reference (%d) after invalidate\n",
+ dentry, dentry->d_name.name, d_count(dentry));
+ mutex_unlock(&eventfs_mutex);
}
/**
* eventfs_remove_rec - remove eventfs dir or file from list
* @ef: eventfs_file to be removed.
+ * @head: to create list of eventfs_file to be deleted
* @level: to check recursion depth
*
* The helper function eventfs_remove_rec() is used to clean up and free the
* associated data from eventfs for both of the added functions.
*/
-static void eventfs_remove_rec(struct eventfs_file *ef, int level)
+static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head, int level)
{
struct eventfs_file *ef_child;
@@ -908,16 +916,14 @@ static void eventfs_remove_rec(struct ev
/* search for nested folders or files */
list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list,
lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ef_child, level + 1);
+ eventfs_remove_rec(ef_child, head, level + 1);
}
}
ef->is_freed = 1;
- unhook_dentry(ef->dentry);
-
list_del_rcu(&ef->list);
- call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef);
+ list_add_tail(&ef->del_list, head);
}
/**
@@ -928,22 +934,28 @@ static void eventfs_remove_rec(struct ev
*/
void eventfs_remove(struct eventfs_file *ef)
{
- struct dentry *dentry;
+ struct eventfs_file *tmp;
+ LIST_HEAD(ef_del_list);
if (!ef)
return;
+ /*
+ * Move the deleted eventfs_inodes onto the ei_del_list
+ * which will also set the is_freed value. Note, this has to be
+ * done under the eventfs_mutex, but the deletions of
+ * the dentries must be done outside the eventfs_mutex.
+ * Hence moving them to this temporary list.
+ */
mutex_lock(&eventfs_mutex);
- dentry = ef->dentry;
- eventfs_remove_rec(ef, 0);
+ eventfs_remove_rec(ef, &ef_del_list, 0);
mutex_unlock(&eventfs_mutex);
- /*
- * If any of the ei children has a dentry, then the ei itself
- * must have a dentry.
- */
- if (dentry)
- simple_recursive_removal(dentry, NULL);
+ list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
+ unhook_dentry(ef->dentry);
+ list_del(&ef->del_list);
+ call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef);
+ }
}
/**
@@ -954,8 +966,6 @@ void eventfs_remove(struct eventfs_file
*/
void eventfs_remove_events_dir(struct dentry *dentry)
{
- struct eventfs_file *ef_child;
- struct eventfs_inode *ei;
struct tracefs_inode *ti;
if (!dentry || !dentry->d_inode)
@@ -965,11 +975,6 @@ void eventfs_remove_events_dir(struct de
if (!ti || !(ti->flags & TRACEFS_EVENT_INODE))
return;
- mutex_lock(&eventfs_mutex);
- ei = ti->private;
- list_for_each_entry_srcu(ef_child, &ei->e_top_files, list,
- lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ef_child, 0);
- }
- mutex_unlock(&eventfs_mutex);
+ d_invalidate(dentry);
+ dput(dentry);
}
Patches currently in stable-queue which might be from rostedt@xxxxxxxxxx are
queue-6.6/eventfs-keep-all-directory-links-at-1.patch
queue-6.6/eventfs-make-sure-that-parent-d_inode-is-locked-in-creating-files-dirs.patch
queue-6.6/eventfs-save-directory-inodes-in-the-eventfs_inode-structure.patch
queue-6.6/revert-eventfs-save-ownership-and-mode.patch
queue-6.6/tracefs-zero-out-the-tracefs_inode-when-allocating-it.patch
queue-6.6/eventfs-read-ei-entries-before-ei-children-in-eventfs_iterate.patch
queue-6.6/eventfs-do-not-invalidate-dentry-in-create_file-dir_dentry.patch
queue-6.6/eventfs-fix-file-and-directory-uid-and-gid-ownership.patch
queue-6.6/eventfs-remove-lookup-parameter-from-create_dir-file_dentry.patch
queue-6.6/eventfs-use-gfp_nofs-for-allocation-when-eventfs_mutex-is-held.patch
queue-6.6/eventfs-remove-fsnotify-functions-from-lookup.patch
queue-6.6/eventfs-use-err_cast-in-eventfs_create_events_dir.patch
queue-6.6/revert-eventfs-use-simple_recursive_removal-to-clean-up-dentries.patch
queue-6.6/eventfs-use-simple_recursive_removal-to-clean-up-dentries.patch
queue-6.6/eventfs-stop-using-dcache_readdir-for-getdents.patch
queue-6.6/eventfs-have-event-files-and-directories-default-to-parent-uid-and-gid.patch
queue-6.6/eventfs-use-eventfs_remove_events_dir.patch
queue-6.6/eventfs-delete-eventfs_inode-when-the-last-dentry-is-freed.patch
queue-6.6/tracefs-avoid-using-the-ei-dentry-pointer-unnecessarily.patch
queue-6.6/tracefs-remove-stale-update_gid-code.patch
queue-6.6/eventfs-initialize-the-tracefs-inode-properly.patch
queue-6.6/eventfs-remove-special-processing-of-dput-of-events-directory.patch
queue-6.6/eventfs-save-ownership-and-mode.patch
queue-6.6/tracefs-check-for-dentry-d_inode-exists-in-set_gid.patch
queue-6.6/eventfs-do-ctx-pos-update-for-all-iterations-in-eventfs_iterate.patch
queue-6.6/tracefs-dentry-lookup-crapectomy.patch
queue-6.6/eventfs-move-taking-of-inode_lock-into-dcache_dir_open_wrapper.patch
queue-6.6/eventfs-have-a-free_ei-that-just-frees-the-eventfs_inode.patch
queue-6.6/revert-eventfs-remove-is_freed-union-with-rcu-head.patch
queue-6.6/eventfs-have-the-inodes-all-for-files-and-directories-all-be-the-same.patch
queue-6.6/eventfs-use-kcalloc-instead-of-kzalloc.patch
queue-6.6/eventfs-test-for-ei-is_freed-when-accessing-ei-dentry.patch
queue-6.6/eventfs-fix-bitwise-fields-for-is_events.patch
queue-6.6/eventfs-fix-warn_on-in-create_file_dentry.patch
queue-6.6/eventfs-fix-events-beyond-name_max-blocking-tasks.patch
queue-6.6/eventfs-shortcut-eventfs_iterate-by-skipping-entries-already-read.patch
queue-6.6/revert-eventfs-do-not-allow-null-parent-to-eventfs_start_creating.patch
queue-6.6/eventfs-do-not-allow-null-parent-to-eventfs_start_creating.patch
queue-6.6/eventfs-do-not-create-dentries-nor-inodes-in-iterate_shared.patch
queue-6.6/eventfs-have-eventfs_iterate-stop-immediately-if-ei-is_freed-is-set.patch
queue-6.6/eventfs-fix-typo-in-eventfs_inode-union-comment.patch
queue-6.6/eventfs-remove-expectation-that-ei-is_freed-means-ei-dentry-null.patch
queue-6.6/eventfs-restructure-eventfs_inode-structure-to-be-more-condensed.patch
queue-6.6/eventfs-warn-if-an-eventfs_inode-is-freed-without-is_freed-being-set.patch
queue-6.6/eventfs-get-rid-of-dentry-pointers-without-refcounts.patch
queue-6.6/eventfs-remove-unused-d_parent-pointer-field.patch
queue-6.6/eventfs-hold-eventfs_mutex-when-calling-callback-functions.patch
queue-6.6/eventfs-remove-is_freed-union-with-rcu-head.patch
queue-6.6/tracefs-eventfs-modify-mismatched-function-name.patch
queue-6.6/eventfs-fix-kerneldoc-of-eventfs_remove_rec.patch
queue-6.6/tracefs-eventfs-use-root-and-instance-inodes-as-default-ownership.patch
queue-6.6/revert-eventfs-check-for-null-ef-in-eventfs_set_attr.patch
queue-6.6/eventfs-fix-failure-path-in-eventfs_create_events_dir.patch
queue-6.6/eventfs-clean-up-dentry-ops-and-add-revalidate-function.patch
