1 files changed, 51 insertions, 25 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 829af323f288..e046c9b6a9dd 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -17,6 +17,7 @@
 #include <linux/nfs_page.h>
 #include <linux/nfs_fs.h>
 #include <linux/nfs_mount.h>
+#include <linux/writeback.h>
 
 #define NFS_PARANOIA 1
 
@@ -268,11 +269,10 @@ nfs_coalesce_requests(struct list_head *head, struct list_head *dst,
 
 #define NFS_SCAN_MAXENTRIES 16
 /**
- * nfs_scan_lock_dirty - Scan the radix tree for dirty requests
- * @nfsi: NFS inode
+ * nfs_scan_dirty - Scan the radix tree for dirty requests
+ * @mapping: pointer to address space
+ * @wbc: writeback_control structure
  * @dst: Destination list
- * @idx_start: lower bound of page->index to scan
- * @npages: idx_start + npages sets the upper bound to scan.
  *
  * Moves elements from one of the inode request lists.
  * If the number of requests is set to 0, the entire address_space
@@ -280,46 +280,72 @@ nfs_coalesce_requests(struct list_head *head, struct list_head *dst,
  * The requests are *not* checked to ensure that they form a contiguous set.
  * You must be holding the inode's req_lock when calling this function
  */
-int
-nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst,
-	      unsigned long idx_start, unsigned int npages)
+long nfs_scan_dirty(struct address_space *mapping,
+			struct writeback_control *wbc,
+			struct list_head *dst)
 {
+	struct nfs_inode *nfsi = NFS_I(mapping->host);
 	struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES];
 	struct nfs_page *req;
-	unsigned long idx_end;
+	pgoff_t idx_start, idx_end;
+	long count = wbc->nr_to_write;
+	long res = 0;
 	int found, i;
-	int res;
 
-	res = 0;
-	if (npages == 0)
-		idx_end = ~0;
-	else
-		idx_end = idx_start + npages - 1;
+	if (nfsi->ndirty == 0 || count <= 0)
+		return 0;
+	if (wbc->range_cyclic) {
+		idx_start = 0;
+		idx_end = ULONG_MAX;
+	} else if (wbc->range_end == 0) {
+		idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
+		idx_end = ULONG_MAX;
+	} else {
+		idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
+		idx_end = wbc->range_end >> PAGE_CACHE_SHIFT;
+	}
 
 	for (;;) {
+		unsigned int toscan = NFS_SCAN_MAXENTRIES;
+
+		if (toscan > count)
+			toscan = count;
 		found = radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree,
-				(void **)&pgvec[0], idx_start, NFS_SCAN_MAXENTRIES,
+				(void **)&pgvec[0], idx_start, toscan,
 				NFS_PAGE_TAG_DIRTY);
+
+		/* Did we make progress? */
 		if (found <= 0)
 			break;
+
 		for (i = 0; i < found; i++) {
 			req = pgvec[i];
-			if (req->wb_index > idx_end)
+			if (!wbc->range_cyclic && req->wb_index > idx_end)
 				goto out;
 
-			idx_start = req->wb_index + 1;
+			/* Try to lock request and mark it for writeback */
+			if (!nfs_set_page_writeback_locked(req))
+				goto next;
+			radix_tree_tag_clear(&nfsi->nfs_page_tree,
+					req->wb_index, NFS_PAGE_TAG_DIRTY);
+			nfsi->ndirty--;
+			nfs_list_remove_request(req);
+			nfs_list_add_request(req, dst);
+			dec_zone_page_state(req->wb_page, NR_FILE_DIRTY);
+			res++;
+			if (res == LONG_MAX)
+				goto out;
+			count--;
+			if (count == 0)
+				goto out;
 
-			if (nfs_set_page_writeback_locked(req)) {
-				radix_tree_tag_clear(&nfsi->nfs_page_tree,
-						req->wb_index, NFS_PAGE_TAG_DIRTY);
-				nfs_list_remove_request(req);
-				nfs_list_add_request(req, dst);
-				dec_zone_page_state(req->wb_page, NR_FILE_DIRTY);
-				res++;
-			}
+next:
+			idx_start = req->wb_index + 1;
 		}
 	}
 out:
+	wbc->nr_to_write = count;
+	WARN_ON ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty));
 	return res;
 }