Re: [PATCH] memory mapped files not updating timestamps

Peter Staubach a écrit :

--- linux-2.6.16.i686/mm/msync.c.org
+++ linux-2.6.16.i686/mm/msync.c

@@ -206,12 +206,16 @@ asmlinkage long sys_msync(unsigned long file = vma->vm_file;

 		start = vma->vm_end;
 		if ((flags & MS_ASYNC) && file && nr_pages_dirtied) {
+			struct address_space *mapping = file->f_mapping;
+
 			get_file(file);
 			up_read(&current->mm->mmap_sem);
-			balance_dirty_pages_ratelimited_nr(file->f_mapping,
+			balance_dirty_pages_ratelimited_nr(mapping,
 							nr_pages_dirtied);
 			fput(file);

<here>, another thread can perform an munmap(), and the file can be totally dismantled.

 			down_read(&current->mm->mmap_sem);

So referencing 'mapping' is *buggy* here.
I believe that you have to move 'fput(file);' *after* the folloging two lines.

+			if (test_and_clear_bit(AS_MCTIME, &mapping->flags))
+				inode_update_time(mapping->host);
 			vma = find_vma(current->mm, start);
 		} else if ((flags & MS_SYNC) && file &&
 				(vma->vm_flags & VM_SHARED)) {

Eric
-
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