1 files changed, 34 insertions, 0 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 3277f3b23524..c4fe97f5ace0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2020,6 +2020,7 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i
                 if (unlikely(*pos + *count > inode->i_sb->s_maxbytes))
                         *count = inode->i_sb->s_maxbytes - *pos;
         } else {
+#ifdef CONFIG_BLOCK
                 loff_t isize;
                 if (bdev_read_only(I_BDEV(inode)))
                         return -EPERM;
@@ -2031,6 +2032,9 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i
 
                 if (*pos + *count > isize)
                         *count = isize - *pos;
+#else
+                return -EPERM;
+#endif
         }
         return 0;
 }
@@ -2491,3 +2495,33 @@ generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
         }
         return retval;
 }
+
+/**
+ * try_to_release_page() - release old fs-specific metadata on a page
+ *
+ * @page: the page which the kernel is trying to free
+ * @gfp_mask: memory allocation flags (and I/O mode)
+ *
+ * The address_space is to try to release any data against the page
+ * (presumably at page->private).  If the release was successful, return `1'.
+ * Otherwise return zero.
+ *
+ * The @gfp_mask argument specifies whether I/O may be performed to release
+ * this page (__GFP_IO), and whether the call may block (__GFP_WAIT).
+ *
+ * NOTE: @gfp_mask may go away, and this function may become non-blocking.
+ */
+int try_to_release_page(struct page *page, gfp_t gfp_mask)
+{
+        struct address_space * const mapping = page->mapping;
+
+        BUG_ON(!PageLocked(page));
+        if (PageWriteback(page))
+                return 0;
+
+        if (mapping && mapping->a_ops->releasepage)
+                return mapping->a_ops->releasepage(page, gfp_mask);
+        return try_to_free_buffers(page);
+}
+
+EXPORT_SYMBOL(try_to_release_page);