If a filesystem's ->writepage implementation repeatedly refuses to write the
page (it keeps on redirtying it instead) (reiserfs seems to do this) then the
writebakc logic can get stuck repeately trying to write the same page.

Fix that up by correctly setting wbc->pages_skipped, to tell the writeback
logic that things aren't working out.


---

 25-sparc64-akpm/fs/buffer.c         |    2 +-
 25-sparc64-akpm/fs/ext3/inode.c     |    6 +++---
 25-sparc64-akpm/fs/ntfs/aops.c      |   19 +++++--------------
 25-sparc64-akpm/fs/reiserfs/inode.c |    2 +-
 25-sparc64-akpm/include/linux/mm.h  |    2 ++
 25-sparc64-akpm/mm/page-writeback.c |   12 ++++++++++++
 6 files changed, 24 insertions(+), 19 deletions(-)

diff -puN fs/buffer.c~writeback-livelock-fix fs/buffer.c
--- 25-sparc64/fs/buffer.c~writeback-livelock-fix	2004-04-21 00:46:16.689584808 -0700
+++ 25-sparc64-akpm/fs/buffer.c	2004-04-21 00:46:16.702582832 -0700
@@ -1826,7 +1826,7 @@ static int __block_write_full_page(struc
 		if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
 			lock_buffer(bh);
 		} else if (test_set_buffer_locked(bh)) {
-			__set_page_dirty_nobuffers(page);
+			redirty_page_for_writepage(wbc, page);
 			continue;
 		}
 		if (test_clear_buffer_dirty(bh)) {
diff -puN fs/ext3/inode.c~writeback-livelock-fix fs/ext3/inode.c
--- 25-sparc64/fs/ext3/inode.c~writeback-livelock-fix	2004-04-21 00:46:16.691584504 -0700
+++ 25-sparc64-akpm/fs/ext3/inode.c	2004-04-21 00:46:16.704582528 -0700
@@ -1311,7 +1311,7 @@ static int ext3_ordered_writepage(struct
 	return ret;
 
 out_fail:
-	__set_page_dirty_nobuffers(page);
+	redirty_page_for_writepage(wbc, page);
 	unlock_page(page);
 	return ret;
 }
@@ -1340,7 +1340,7 @@ static int ext3_writeback_writepage(stru
 	return ret;
 
 out_fail:
-	__set_page_dirty_nobuffers(page);
+	redirty_page_for_writepage(wbc, page);
 	unlock_page(page);
 	return ret;
 }
@@ -1396,7 +1396,7 @@ out:
 	return ret;
 
 no_write:
-	__set_page_dirty_nobuffers(page);
+	redirty_page_for_writepage(wbc, page);
 out_unlock:
 	unlock_page(page);
 	goto out;
diff -puN fs/ntfs/aops.c~writeback-livelock-fix fs/ntfs/aops.c
--- 25-sparc64/fs/ntfs/aops.c~writeback-livelock-fix	2004-04-21 00:46:16.693584200 -0700
+++ 25-sparc64-akpm/fs/ntfs/aops.c	2004-04-21 00:50:09.080256056 -0700
@@ -458,7 +458,7 @@ err_out:
  *
  * Based on ntfs_read_block() and __block_write_full_page().
  */
-static int ntfs_write_block(struct page *page)
+static int ntfs_write_block(struct writeback_control *wbc, struct page *page)
 {
 	VCN vcn;
 	LCN lcn;
@@ -499,10 +499,7 @@ static int ntfs_write_block(struct page 
 		 * Put the page back on mapping->dirty_pages, but leave its
 		 * buffer's dirty state as-is.
 		 */
-		// FIXME: Once Andrew's -EAGAIN patch goes in, remove the
-		// __set_page_dirty_nobuffers(page) and return -EAGAIN instead
-		// of zero.
-		__set_page_dirty_nobuffers(page);
+		redirty_page_for_writepage(wbc, page);
 		unlock_page(page);
 		return 0;
 	}
@@ -733,10 +730,7 @@ lock_retry_remap:
 			 * Put the page back on mapping->dirty_pages, but
 			 * leave its buffer's dirty state as-is.
 			 */
-			// FIXME: Once Andrew's -EAGAIN patch goes in, remove
-			// the __set_page_dirty_nobuffers(page) and set err to
-			// -EAGAIN instead of zero.
-			__set_page_dirty_nobuffers(page);
+			redirty_page_for_writepage(wbc, page);
 			err = 0;
 		} else
 			SetPageError(page);
@@ -869,7 +863,7 @@ static int ntfs_writepage(struct page *p
 		}
 
 		/* Normal data stream. */
-		return ntfs_write_block(page);
+		return ntfs_write_block(wbc, page);
 	}
 
 	/*
@@ -986,10 +980,7 @@ err_out:
 		 * Put the page back on mapping->dirty_pages, but leave its
 		 * buffer's dirty state as-is.
 		 */
-		// FIXME: Once Andrew's -EAGAIN patch goes in, remove the
-		// __set_page_dirty_nobuffers(page) and set err to -EAGAIN
-		// instead of zero.
-		__set_page_dirty_nobuffers(page);
+		redirty_page_for_writepage(wbc, page);
 		err = 0;
 	} else {
 		ntfs_error(vi->i_sb, "Resident attribute write failed with "
diff -puN fs/reiserfs/inode.c~writeback-livelock-fix fs/reiserfs/inode.c
--- 25-sparc64/fs/reiserfs/inode.c~writeback-livelock-fix	2004-04-21 00:46:16.694584048 -0700
+++ 25-sparc64-akpm/fs/reiserfs/inode.c	2004-04-21 00:46:16.708581920 -0700
@@ -2112,7 +2112,7 @@ static int reiserfs_write_full_page(stru
 	    lock_buffer(bh);
 	} else {
 	    if (test_set_buffer_locked(bh)) {
-		__set_page_dirty_nobuffers(page);
+		redirty_page_for_writepage(wbc, page);
 		continue;
 	    }
 	}
diff -puN include/linux/mm.h~writeback-livelock-fix include/linux/mm.h
--- 25-sparc64/include/linux/mm.h~writeback-livelock-fix	2004-04-21 00:46:16.696583744 -0700
+++ 25-sparc64-akpm/include/linux/mm.h	2004-04-21 00:46:16.709581768 -0700
@@ -499,6 +499,8 @@ int get_user_pages(struct task_struct *t
 
 int __set_page_dirty_buffers(struct page *page);
 int __set_page_dirty_nobuffers(struct page *page);
+int redirty_page_for_writepage(struct writeback_control *wbc,
+				struct page *page);
 int FASTCALL(set_page_dirty(struct page *page));
 int set_page_dirty_lock(struct page *page);
 int clear_page_dirty_for_io(struct page *page);
diff -puN mm/page-writeback.c~writeback-livelock-fix mm/page-writeback.c
--- 25-sparc64/mm/page-writeback.c~writeback-livelock-fix	2004-04-21 00:46:16.697583592 -0700
+++ 25-sparc64-akpm/mm/page-writeback.c	2004-04-21 00:46:16.710581616 -0700
@@ -581,6 +581,18 @@ int __set_page_dirty_nobuffers(struct pa
 EXPORT_SYMBOL(__set_page_dirty_nobuffers);
 
 /*
+ * When a writepage implementation decides that it doesn't want to write this
+ * page for some reason, it should redirty the locked page via
+ * redirty_page_for_writepage() and it should then unlock the page and return 0
+ */
+int redirty_page_for_writepage(struct writeback_control *wbc, struct page *page)
+{
+	wbc->pages_skipped++;
+	return __set_page_dirty_nobuffers(page);
+}
+EXPORT_SYMBOL(redirty_page_for_writepage);
+
+/*
  * If the mapping doesn't provide a set_page_dirty a_op, then
  * just fall through and assume that it wants buffer_heads.
  */

_