fs: get mnt_writers count for an open backing file's real path

[linux-2.6-block.git] / fs / internal.h

diff --git a/fs/internal.h b/fs/internal.h
index d64ae03998cce9dcffdad33baa3e52f4f7dc8983..4e93a685bdaa6e88e4f8d6f0e4b2b5d082a5148c 100644 (file)
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -73,8 +73,8 @@ extern int sb_prepare_remount_readonly(struct super_block *);
 
 extern void __init mnt_init(void);
 
-extern int __mnt_want_write_file(struct file *);
-extern void __mnt_drop_write_file(struct file *);
+int mnt_get_write_access_file(struct file *file);
+void mnt_put_write_access_file(struct file *file);
 
 extern void dissolve_on_fput(struct vfsmount *);
 extern bool may_mount(void);
@@ -94,14 +94,22 @@ extern void chroot_fs_refs(const struct path *, const struct path *);
 struct file *alloc_empty_file(int flags, const struct cred *cred);
 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
 struct file *alloc_empty_backing_file(int flags, const struct cred *cred);
+void release_empty_file(struct file *f);
+
+static inline void file_put_write_access(struct file *file)
+{
+       put_write_access(file->f_inode);
+       mnt_put_write_access(file->f_path.mnt);
+       if (unlikely(file->f_mode & FMODE_BACKING))
+               mnt_put_write_access(backing_file_real_path(file)->mnt);
+}
 
 static inline void put_file_access(struct file *file)
 {
        if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
                i_readcount_dec(file->f_inode);
        } else if (file->f_mode & FMODE_WRITER) {
-               put_write_access(file->f_inode);
-               __mnt_drop_write(file->f_path.mnt);
+               file_put_write_access(file);
        }
 }
 
@@ -130,9 +138,9 @@ static inline void sb_start_ro_state_change(struct super_block *sb)
         * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY
         * cleared, it will see s_readonly_remount set.
         * For RW->RO transition, the barrier pairs with the barrier in
-        * __mnt_want_write() before the mnt_is_readonly() check. The barrier
-        * makes sure if __mnt_want_write() sees MNT_WRITE_HOLD already
-        * cleared, it will see s_readonly_remount set.
+        * mnt_get_write_access() before the mnt_is_readonly() check.
+        * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD
+        * already cleared, it will see s_readonly_remount set.
         */
        smp_wmb();
 }