mmap: proper locking to interoperate with branch-management code

Include proper read un/lock calls as in file.c.  Make unionfs_do_readpage
static as no one else should call this helper function.

diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
index 5302dcdfa12de21ce560564ca5d6c5ce44b2b41e..ade8c926b26fd4de7bb6bb768d7465898119ef43 100644 (file)
--- a/fs/unionfs/mmap.c
+++ b/fs/unionfs/mmap.c
@@ -73,7 +73,7 @@ out:
  *
  * Readpage expects a locked page, and must unlock it.
  */
-int unionfs_do_readpage(struct file *file, struct page *page)
+static int unionfs_do_readpage(struct file *file, struct page *page)
 {
        int err = -EIO;
        struct dentry *dentry;
@@ -162,6 +162,7 @@ int unionfs_readpage(struct file *file, struct page *page)
 {
        int err;
 
+       unionfs_read_lock(file->f_dentry->d_sb);
        if ((err = unionfs_file_revalidate(file, 0)))
                goto out_err;
 
@@ -175,6 +176,7 @@ int unionfs_readpage(struct file *file, struct page *page)
 
 out_err:
        unlock_page(page);
+       unionfs_read_unlock(file->f_dentry->d_sb);
 
        return err;
 }
@@ -182,7 +184,13 @@ out_err:
 int unionfs_prepare_write(struct file *file, struct page *page, unsigned from,
                          unsigned to)
 {
-       return unionfs_file_revalidate(file, 1);
+       int err;
+
+       unionfs_read_lock(file->f_dentry->d_sb);
+       err = unionfs_file_revalidate(file, 1);
+       unionfs_read_unlock(file->f_dentry->d_sb);
+
+       return err;
 }
 
 int unionfs_commit_write(struct file *file, struct page *page, unsigned from,
@@ -198,6 +206,7 @@ int unionfs_commit_write(struct file *file, struct page *page, unsigned from,
 
        BUG_ON(file == NULL);
 
+       unionfs_read_lock(file->f_dentry->d_sb);
        if ((err = unionfs_file_revalidate(file, 1)))
                goto out;
 
@@ -247,6 +256,7 @@ out:
        if (err < 0)
                ClearPageUptodate(page);
 
+       unionfs_read_unlock(file->f_dentry->d_sb);
        return err;             /* assume all is ok */
 }