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-rw-r--r--fs/buffer.c55
1 files changed, 52 insertions, 3 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index d2a4d1bb2d57..4d7433534f5c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -83,6 +83,40 @@ void unlock_buffer(struct buffer_head *bh)
EXPORT_SYMBOL(unlock_buffer);
/*
+ * Returns if the page has dirty or writeback buffers. If all the buffers
+ * are unlocked and clean then the PageDirty information is stale. If
+ * any of the pages are locked, it is assumed they are locked for IO.
+ */
+void buffer_check_dirty_writeback(struct page *page,
+ bool *dirty, bool *writeback)
+{
+ struct buffer_head *head, *bh;
+ *dirty = false;
+ *writeback = false;
+
+ BUG_ON(!PageLocked(page));
+
+ if (!page_has_buffers(page))
+ return;
+
+ if (PageWriteback(page))
+ *writeback = true;
+
+ head = page_buffers(page);
+ bh = head;
+ do {
+ if (buffer_locked(bh))
+ *writeback = true;
+
+ if (buffer_dirty(bh))
+ *dirty = true;
+
+ bh = bh->b_this_page;
+ } while (bh != head);
+}
+EXPORT_SYMBOL(buffer_check_dirty_writeback);
+
+/*
* Block until a buffer comes unlocked. This doesn't stop it
* from becoming locked again - you have to lock it yourself
* if you want to preserve its state.
@@ -1454,7 +1488,8 @@ static void discard_buffer(struct buffer_head * bh)
* block_invalidatepage - invalidate part or all of a buffer-backed page
*
* @page: the page which is affected
- * @offset: the index of the truncation point
+ * @offset: start of the range to invalidate
+ * @length: length of the range to invalidate
*
* block_invalidatepage() is called when all or part of the page has become
* invalidated by a truncate operation.
@@ -1465,15 +1500,22 @@ static void discard_buffer(struct buffer_head * bh)
* point. Because the caller is about to free (and possibly reuse) those
* blocks on-disk.
*/
-void block_invalidatepage(struct page *page, unsigned long offset)
+void block_invalidatepage(struct page *page, unsigned int offset,
+ unsigned int length)
{
struct buffer_head *head, *bh, *next;
unsigned int curr_off = 0;
+ unsigned int stop = length + offset;
BUG_ON(!PageLocked(page));
if (!page_has_buffers(page))
goto out;
+ /*
+ * Check for overflow
+ */
+ BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
+
head = page_buffers(page);
bh = head;
do {
@@ -1481,6 +1523,12 @@ void block_invalidatepage(struct page *page, unsigned long offset)
next = bh->b_this_page;
/*
+ * Are we still fully in range ?
+ */
+ if (next_off > stop)
+ goto out;
+
+ /*
* is this block fully invalidated?
*/
if (offset <= curr_off)
@@ -1501,6 +1549,7 @@ out:
}
EXPORT_SYMBOL(block_invalidatepage);
+
/*
* We attach and possibly dirty the buffers atomically wrt
* __set_page_dirty_buffers() via private_lock. try_to_free_buffers
@@ -2841,7 +2890,7 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block,
* they may have been added in ext3_writepage(). Make them
* freeable here, so the page does not leak.
*/
- do_invalidatepage(page, 0);
+ do_invalidatepage(page, 0, PAGE_CACHE_SIZE);
unlock_page(page);
return 0; /* don't care */
}