From: "Steven Rostedt (Google)" rostedt@goodmis.org
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@goodmis.org --- fs/tracefs/event_inode.c | 71 +++++++++++++++++++++------------------- 1 file changed, 38 insertions(+), 33 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 5fcfb634fec2..7aa92b8ebc51 100644 --- 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 *ef) */ 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 tracefs_inode *ti, struct dentry *dentry)
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 *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 eventfs_file *ef, int level) /* 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 eventfs_file *ef, int level) */ 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 *ef) */ 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 dentry *dentry) 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); }