[RFC:PATCH 008/008] Handle file tails in mm/filemap.c

[Dave Kleikamp <shaggy@austin.ibm.com>]

Handle file tails in mm/filemap.c

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
---
diff -Nurp linux007/mm/filemap.c linux008/mm/filemap.c
--- linux007/mm/filemap.c	2006-06-17 20:49:35.000000000 -0500
+++ linux008/mm/filemap.c	2006-07-17 23:04:38.000000000 -0500
@@ -30,6 +30,7 @@
 #include <linux/security.h>
 #include <linux/syscalls.h>
 #include <linux/cpuset.h>
+#include <linux/file_tail.h>
 #include "filemap.h"
 #include "internal.h"
 
@@ -117,6 +118,12 @@ void __remove_from_page_cache(struct pag
 {
 	struct address_space *mapping = page->mapping;
 
+#ifdef CONFIG_FILE_TAILS
+	if (PageTail(page)) {
+		kfree(mapping->tail);
+		mapping->tail = NULL;
+	}
+#endif
 	radix_tree_delete(&mapping->page_tree, page->index);
 	page->mapping = NULL;
 	mapping->nrpages--;
@@ -885,6 +892,11 @@ page_ok:
 		index += offset >> PAGE_CACHE_SHIFT;
 		offset &= ~PAGE_CACHE_MASK;
 
+#ifdef CONFIG_FILE_TAILS
+		if (!mapping->tail && page->index == FILE_TAIL_INDEX(mapping) &&
+		    !PageDirty(page))
+			pack_file_tail(page);
+#endif
 		page_cache_release(page);
 		if (ret == nr && desc->count)
 			continue;
@@ -2030,6 +2042,16 @@ generic_file_buffered_write(struct kiocb
 			break;
 		}
 
+#ifdef CONFIG_FILE_TAILS
+		if (PageTail(page)) {
+			/* Can't unpack the tail while holding the tail page */
+			unlock_page(page);
+			page_cache_release(page);
+			unpack_file_tail(mapping);
+			continue;
+		}
+#endif
+
 		status = a_ops->prepare_write(file, page, offset, offset+bytes);
 		if (unlikely(status)) {
 			loff_t isize = i_size_read(inode);

-- 
David Kleikamp
IBM Linux Technology Center

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>