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-rw-r--r--mm/filemap.c30
-rw-r--r--mm/page-writeback.c1
-rw-r--r--mm/truncate.c24
3 files changed, 55 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 3277f3b23524..d6846de08887 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2491,3 +2491,33 @@ 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);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 488b7088557c..9fdcc7903956 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -30,6 +30,7 @@
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/syscalls.h>
+#include <linux/buffer_head.h>
/*
* The maximum number of pages to writeout in a single bdflush/kupdate
diff --git a/mm/truncate.c b/mm/truncate.c
index a654928323dc..cd3e34b816db 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -17,6 +17,30 @@
do_invalidatepage */
+/**
+ * do_invalidatepage - invalidate part of all of a page
+ * @page: the page which is affected
+ * @offset: the index of the truncation point
+ *
+ * do_invalidatepage() is called when all or part of the page has become
+ * invalidated by a truncate operation.
+ *
+ * do_invalidatepage() does not have to release all buffers, but it must
+ * ensure that no dirty buffer is left outside @offset and that no I/O
+ * is underway against any of the blocks which are outside the truncation
+ * point. Because the caller is about to free (and possibly reuse) those
+ * blocks on-disk.
+ */
+void do_invalidatepage(struct page *page, unsigned long offset)
+{
+ void (*invalidatepage)(struct page *, unsigned long);
+ invalidatepage = page->mapping->a_ops->invalidatepage;
+ if (!invalidatepage)
+ invalidatepage = block_invalidatepage;
+ if (invalidatepage)
+ (*invalidatepage)(page, offset);
+}
+
static inline void truncate_partial_page(struct page *page, unsigned partial)
{
memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial);