1 files changed, 6 insertions, 2 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 60829565e552..23b2a35d712e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -123,6 +123,9 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 /* File is opened with O_PATH; almost nothing can be done with it */
 #define FMODE_PATH              ((__force fmode_t)0x4000)
 
+/* File needs atomic accesses to f_pos */
+#define FMODE_ATOMIC_POS        ((__force fmode_t)0x8000)
+
 /* File was opened by fanotify and shouldn't generate fanotify events */
 #define FMODE_NONOTIFY          ((__force fmode_t)0x1000000)
 
@@ -780,13 +783,14 @@ struct file {
         const struct file_operations    *f_op;
 
         /*
-         * Protects f_ep_links, f_flags, f_pos vs i_size in lseek SEEK_CUR.
+         * Protects f_ep_links, f_flags.
          * Must not be taken from IRQ context.
          */
         spinlock_t              f_lock;
         atomic_long_t           f_count;
         unsigned int            f_flags;
         fmode_t                 f_mode;
+        struct mutex            f_pos_lock;
         loff_t                  f_pos;
         struct fown_struct      f_owner;
         const struct cred       *f_cred;
@@ -808,7 +812,7 @@ struct file {
 #ifdef CONFIG_DEBUG_WRITECOUNT
         unsigned long f_mnt_write_state;
 #endif
-};
+} __attribute__((aligned(4)));  /* lest something weird decides that 2 is OK */
 
 struct file_handle {
         __u32 handle_bytes;