diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
index db3889b..fb58622 100644
--- a/fs/jffs2/file.c
+++ b/fs/jffs2/file.c
@@ -142,9 +142,12 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
        uint32_t pageofs = index << PAGE_CACHE_SHIFT;
        int ret = 0;

+       mutex_lock(&f->sem);
        pg = grab_cache_page_write_begin(mapping, index, flags);
-       if (!pg)
+       if (!pg) {
+               mutex_unlock(&f->sem);
                return -ENOMEM;
+       }
        *pagep = pg;

        jffs2_dbg(1, "%s()\n", __func__);
@@ -164,7 +167,6 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
                if (ret)
                        goto out_page;

-               mutex_lock(&f->sem);
                memset(&ri, 0, sizeof(ri));

                ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
@@ -191,7 +193,6 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
                if (IS_ERR(fn)) {
                        ret = PTR_ERR(fn);
                        jffs2_complete_reservation(c);
-                       mutex_unlock(&f->sem);
                        goto out_page;
                }
                ret = jffs2_add_full_dnode_to_inode(c, f, fn);
@@ -206,12 +207,10 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
                        jffs2_mark_node_obsolete(c, fn->raw);
                        jffs2_free_full_dnode(fn);
                        jffs2_complete_reservation(c);
-                       mutex_unlock(&f->sem);
                        goto out_page;
                }
                jffs2_complete_reservation(c);
                inode->i_size = pageofs;
-               mutex_unlock(&f->sem);
        }

        /*
@@ -220,18 +219,18 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
         * case of a short-copy.
         */
        if (!PageUptodate(pg)) {
-               mutex_lock(&f->sem);
                ret = jffs2_do_readpage_nolock(inode, pg);
-               mutex_unlock(&f->sem);
                if (ret)
                        goto out_page;
        }
+       mutex_unlock(&f->sem);
        jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
        return ret;

 out_page:
        unlock_page(pg);
        page_cache_release(pg);
+       mutex_unlock(&f->sem);
        return ret;
 }