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path: root/fs/kernfs/file.c
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Diffstat (limited to 'fs/kernfs/file.c')
-rw-r--r--fs/kernfs/file.c67
1 files changed, 45 insertions, 22 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index 8502ef68459b..9adf36e6364b 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -70,6 +70,24 @@ static struct kernfs_open_node *of_on(struct kernfs_open_file *of)
!list_empty(&of->list));
}
+/* Get active reference to kernfs node for an open file */
+static struct kernfs_open_file *kernfs_get_active_of(struct kernfs_open_file *of)
+{
+ /* Skip if file was already released */
+ if (unlikely(of->released))
+ return NULL;
+
+ if (!kernfs_get_active(of->kn))
+ return NULL;
+
+ return of;
+}
+
+static void kernfs_put_active_of(struct kernfs_open_file *of)
+{
+ return kernfs_put_active(of->kn);
+}
+
/**
* kernfs_deref_open_node_locked - Get kernfs_open_node corresponding to @kn
*
@@ -139,7 +157,7 @@ static void kernfs_seq_stop_active(struct seq_file *sf, void *v)
if (ops->seq_stop)
ops->seq_stop(sf, v);
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
}
static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos)
@@ -152,7 +170,7 @@ static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos)
* the ops aren't called concurrently for the same open file.
*/
mutex_lock(&of->mutex);
- if (!kernfs_get_active(of->kn))
+ if (!kernfs_get_active_of(of))
return ERR_PTR(-ENODEV);
ops = kernfs_ops(of->kn);
@@ -238,7 +256,7 @@ static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
* the ops aren't called concurrently for the same open file.
*/
mutex_lock(&of->mutex);
- if (!kernfs_get_active(of->kn)) {
+ if (!kernfs_get_active_of(of)) {
len = -ENODEV;
mutex_unlock(&of->mutex);
goto out_free;
@@ -252,7 +270,7 @@ static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
else
len = -EINVAL;
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
mutex_unlock(&of->mutex);
if (len < 0)
@@ -323,7 +341,7 @@ static ssize_t kernfs_fop_write_iter(struct kiocb *iocb, struct iov_iter *iter)
* the ops aren't called concurrently for the same open file.
*/
mutex_lock(&of->mutex);
- if (!kernfs_get_active(of->kn)) {
+ if (!kernfs_get_active_of(of)) {
mutex_unlock(&of->mutex);
len = -ENODEV;
goto out_free;
@@ -335,7 +353,7 @@ static ssize_t kernfs_fop_write_iter(struct kiocb *iocb, struct iov_iter *iter)
else
len = -EINVAL;
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
mutex_unlock(&of->mutex);
if (len > 0)
@@ -357,13 +375,13 @@ static void kernfs_vma_open(struct vm_area_struct *vma)
if (!of->vm_ops)
return;
- if (!kernfs_get_active(of->kn))
+ if (!kernfs_get_active_of(of))
return;
if (of->vm_ops->open)
of->vm_ops->open(vma);
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
}
static vm_fault_t kernfs_vma_fault(struct vm_fault *vmf)
@@ -375,14 +393,14 @@ static vm_fault_t kernfs_vma_fault(struct vm_fault *vmf)
if (!of->vm_ops)
return VM_FAULT_SIGBUS;
- if (!kernfs_get_active(of->kn))
+ if (!kernfs_get_active_of(of))
return VM_FAULT_SIGBUS;
ret = VM_FAULT_SIGBUS;
if (of->vm_ops->fault)
ret = of->vm_ops->fault(vmf);
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
return ret;
}
@@ -395,7 +413,7 @@ static vm_fault_t kernfs_vma_page_mkwrite(struct vm_fault *vmf)
if (!of->vm_ops)
return VM_FAULT_SIGBUS;
- if (!kernfs_get_active(of->kn))
+ if (!kernfs_get_active_of(of))
return VM_FAULT_SIGBUS;
ret = 0;
@@ -404,7 +422,7 @@ static vm_fault_t kernfs_vma_page_mkwrite(struct vm_fault *vmf)
else
file_update_time(file);
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
return ret;
}
@@ -418,14 +436,14 @@ static int kernfs_vma_access(struct vm_area_struct *vma, unsigned long addr,
if (!of->vm_ops)
return -EINVAL;
- if (!kernfs_get_active(of->kn))
+ if (!kernfs_get_active_of(of))
return -EINVAL;
ret = -EINVAL;
if (of->vm_ops->access)
ret = of->vm_ops->access(vma, addr, buf, len, write);
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
return ret;
}
@@ -455,7 +473,7 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma)
mutex_lock(&of->mutex);
rc = -ENODEV;
- if (!kernfs_get_active(of->kn))
+ if (!kernfs_get_active_of(of))
goto out_unlock;
ops = kernfs_ops(of->kn);
@@ -490,7 +508,7 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma)
}
vma->vm_ops = &kernfs_vm_ops;
out_put:
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
out_unlock:
mutex_unlock(&of->mutex);
@@ -778,8 +796,9 @@ bool kernfs_should_drain_open_files(struct kernfs_node *kn)
/*
* @kn being deactivated guarantees that @kn->attr.open can't change
* beneath us making the lockless test below safe.
+ * Callers post kernfs_unbreak_active_protection may be counted in
+ * kn->active by now, do not WARN_ON because of them.
*/
- WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS);
rcu_read_lock();
on = rcu_dereference(kn->attr.open);
@@ -851,7 +870,7 @@ static __poll_t kernfs_fop_poll(struct file *filp, poll_table *wait)
struct kernfs_node *kn = kernfs_dentry_node(filp->f_path.dentry);
__poll_t ret;
- if (!kernfs_get_active(kn))
+ if (!kernfs_get_active_of(of))
return DEFAULT_POLLMASK|EPOLLERR|EPOLLPRI;
if (kn->attr.ops->poll)
@@ -859,7 +878,7 @@ static __poll_t kernfs_fop_poll(struct file *filp, poll_table *wait)
else
ret = kernfs_generic_poll(of, wait);
- kernfs_put_active(kn);
+ kernfs_put_active_of(of);
return ret;
}
@@ -874,7 +893,7 @@ static loff_t kernfs_fop_llseek(struct file *file, loff_t offset, int whence)
* the ops aren't called concurrently for the same open file.
*/
mutex_lock(&of->mutex);
- if (!kernfs_get_active(of->kn)) {
+ if (!kernfs_get_active_of(of)) {
mutex_unlock(&of->mutex);
return -ENODEV;
}
@@ -885,7 +904,7 @@ static loff_t kernfs_fop_llseek(struct file *file, loff_t offset, int whence)
else
ret = generic_file_llseek(file, offset, whence);
- kernfs_put_active(of->kn);
+ kernfs_put_active_of(of);
mutex_unlock(&of->mutex);
return ret;
}
@@ -911,9 +930,11 @@ repeat:
/* kick fsnotify */
down_read(&root->kernfs_supers_rwsem);
+ down_read(&root->kernfs_rwsem);
list_for_each_entry(info, &kernfs_root(kn)->supers, node) {
struct kernfs_node *parent;
struct inode *p_inode = NULL;
+ const char *kn_name;
struct inode *inode;
struct qstr name;
@@ -927,7 +948,8 @@ repeat:
if (!inode)
continue;
- name = (struct qstr)QSTR_INIT(kn->name, strlen(kn->name));
+ kn_name = kernfs_rcu_name(kn);
+ name = QSTR(kn_name);
parent = kernfs_get_parent(kn);
if (parent) {
p_inode = ilookup(info->sb, kernfs_ino(parent));
@@ -947,6 +969,7 @@ repeat:
iput(inode);
}
+ up_read(&root->kernfs_rwsem);
up_read(&root->kernfs_supers_rwsem);
kernfs_put(kn);
goto repeat;
generated by cgit (git 2.34.1) at 2025-12-22 10:05:11 +0000