Use f_lock to protect f_flags
Traditionally, changes to struct file->f_flags have been done under BKL
protection, or with no protection at all. This patch causes all f_flags
changes after file open/creation time to be done under protection of
f_lock. This allows the removal of some BKL usage and fixes a number of
longstanding (if microscopic) races.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2011600..7428c6d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -848,7 +848,7 @@
#define f_dentry f_path.dentry
#define f_vfsmnt f_path.mnt
const struct file_operations *f_op;
- spinlock_t f_lock; /* f_ep_links */
+ spinlock_t f_lock; /* f_ep_links, f_flags */
atomic_long_t f_count;
unsigned int f_flags;
fmode_t f_mode;