From 7cb537b6f6d7d6529be04139178f929d9a63b918 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 26 Nov 2023 02:08:34 +0000
Subject: [PATCH] file: massage cleanup of files that failed to open
A file that has never gotten FMODE_OPENED will never have RCU-accessed
references, its final fput() is equivalent to file_free() and if it
doesn't have FMODE_BACKING either, it can be done from any context and
won't need task_work treatment.
Now that we have SLAB_TYPESAFE_BY_RCU we can simplify this and have
other callers benefit. All of that can be achieved easier is to make
fput() recoginze that case and call file_free() directly.
No need to introduce a special primitive for that. It also allowed
things like failing dentry_open() could benefit from that as well.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[Christian Brauner <brauner@kernel.org>: massage commit message]
Link: https://lore.kernel.org/r/20231126020834.GC38156@ZenIV
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
fs/file_table.c | 16 ++++------------
fs/internal.h | 1 -
fs/namei.c | 5 +----
3 files changed, 5 insertions(+), 17 deletions(-)
diff --git a/fs/file_table.c b/fs/file_table.c
index de4a2915bfd49..6deac386486d0 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -75,18 +75,6 @@ static inline void file_free(struct file *f)
}
}
-void release_empty_file(struct file *f)
-{
- WARN_ON_ONCE(f->f_mode & (FMODE_BACKING | FMODE_OPENED));
- if (atomic_long_dec_and_test(&f->f_count)) {
- security_file_free(f);
- put_cred(f->f_cred);
- if (likely(!(f->f_mode & FMODE_NOACCOUNT)))
- percpu_counter_dec(&nr_files);
- kmem_cache_free(filp_cachep, f);
- }
-}
-
/*
* Return the total number of open files in the system
*/
@@ -445,6 +433,10 @@ void fput(struct file *file)
if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
+ if (unlikely(!(file->f_mode & (FMODE_BACKING | FMODE_OPENED)))) {
+ file_free(file);
+ return;
+ }
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
init_task_work(&file->f_rcuhead, ____fput);
if (!task_work_add(task, &file->f_rcuhead, TWA_RESUME))
diff --git a/fs/internal.h b/fs/internal.h
index 58e43341aebf0..273e6fd40d1be 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -94,7 +94,6 @@ extern void chroot_fs_refs(const struct path *, const struct path *);
struct file *alloc_empty_file(int flags, const struct cred *cred);
struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
struct file *alloc_empty_backing_file(int flags, const struct cred *cred);
-void release_empty_file(struct file *f);
static inline void file_put_write_access(struct file *file)
{
diff --git a/fs/namei.c b/fs/namei.c
index 71c13b2990b44..f0ead1858267c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3785,10 +3785,7 @@ static struct file *path_openat(struct nameidata *nd,
WARN_ON(1);
error = -EINVAL;
}
- if (unlikely(file->f_mode & FMODE_OPENED))
- fput(file);
- else
- release_empty_file(file);
+ fput(file);
if (error == -EOPENSTALE) {
if (flags & LOOKUP_RCU)
error = -ECHILD;
--
2.30.2