From 03f1f1a7fb63f8972aab7bb28b1756a5f1457507 Mon Sep 17 00:00:00 2001
From: hujun5 <hujun5@xiaomi.com>
Date: Thu, 12 Dec 2024 21:15:51 +0800
Subject: [PATCH] use small lock to protect f_refs

fix regresion from https://github.com/apache/nuttx/pull/14801

Signed-off-by: hujun5 <hujun5@xiaomi.com>
---
 fs/inode/fs_files.c   | 17 +++++++++++------
 include/nuttx/fs/fs.h |  1 +
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/fs/inode/fs_files.c b/fs/inode/fs_files.c
index 8374ad06d3041..2a1408d81f51f 100644
--- a/fs/inode/fs_files.c
+++ b/fs/inode/fs_files.c
@@ -73,9 +73,12 @@ static FAR struct file *files_fget_by_index(FAR struct filelist *list,
   irqstate_t flags;
 
   flags = spin_lock_irqsave(&list->fl_lock);
-
   filep = &list->fl_files[l1][l2];
+  spin_unlock_irqrestore(&list->fl_lock, flags);
+
 #ifdef CONFIG_FS_REFCOUNT
+
+  flags = spin_lock_irqsave(&filep->lock);
   if (filep->f_inode != NULL)
     {
       /* When the reference count is zero but the inode has not yet been
@@ -104,6 +107,8 @@ static FAR struct file *files_fget_by_index(FAR struct filelist *list,
       filep->f_refs = 2;
       *new = true;
     }
+
+  spin_unlock_irqrestore(&filep->lock, flags);
 #else
   if (filep->f_inode == NULL && new == NULL)
     {
@@ -111,7 +116,6 @@ static FAR struct file *files_fget_by_index(FAR struct filelist *list,
     }
 #endif
 
-  spin_unlock_irqrestore(&list->fl_lock, flags);
   return filep;
 }
 
@@ -629,6 +633,7 @@ int file_allocate_from_tcb(FAR struct tcb_s *tcb, FAR struct inode *inode,
               filep->f_priv        = priv;
 #ifdef CONFIG_FS_REFCOUNT
               filep->f_refs        = 1;
+              spin_lock_init(&filep->lock);
 #endif
 #ifdef CONFIG_FDSAN
               filep->f_tag_fdsan   = 0;
@@ -861,9 +866,9 @@ void fs_reffilep(FAR struct file *filep)
   irqstate_t flags;
 
   DEBUGASSERT(filep);
-  flags = spin_lock_irqsave(NULL);
+  flags = spin_lock_irqsave(&filep->lock);
   filep->f_refs++;
-  spin_unlock_irqrestore(NULL, flags);
+  spin_unlock_irqrestore(&filep->lock, flags);
 }
 
 /****************************************************************************
@@ -885,11 +890,11 @@ int fs_putfilep(FAR struct file *filep)
   int refs;
 
   DEBUGASSERT(filep);
-  flags = spin_lock_irqsave(NULL);
+  flags = spin_lock_irqsave(&filep->lock);
 
   refs = --filep->f_refs;
 
-  spin_unlock_irqrestore(NULL, flags);
+  spin_unlock_irqrestore(&filep->lock, flags);
 
   /* If refs is zero, the close() had called, closing it now. */
 
diff --git a/include/nuttx/fs/fs.h b/include/nuttx/fs/fs.h
index e82df41bffea5..6c17a051797e3 100644
--- a/include/nuttx/fs/fs.h
+++ b/include/nuttx/fs/fs.h
@@ -462,6 +462,7 @@ struct file
   int               f_oflags;   /* Open mode flags */
 #ifdef CONFIG_FS_REFCOUNT
   int               f_refs;     /* Reference count */
+  spinlock_t        lock;       /* Reference spinlock */
 #endif
   off_t             f_pos;      /* File position */
   FAR struct inode *f_inode;    /* Driver or file system interface */