logfs: update page reference count for pined pages
LogFS sets PG_private flag to indicate a pined page. We assumed that
marking a page as private is enough to ensure its existence. But
instead it is necessary to hold a reference count to the page.
The change resolves the following BUG
BUG: Bad page state in process flush-253:16 pfn:6a6d0
page flags: 0x100000000000808(uptodate|private)
Suggested-and-Acked-by: Joern Engel <joern@logfs.org>
Signed-off-by: Prasad Joshi <prasadjoshi.linux@gmail.com>
diff --git a/fs/logfs/readwrite.c b/fs/logfs/readwrite.c
index 2ac4217..6d663e8 100644
--- a/fs/logfs/readwrite.c
+++ b/fs/logfs/readwrite.c
@@ -560,8 +560,13 @@
static void indirect_free_block(struct super_block *sb,
struct logfs_block *block)
{
- ClearPagePrivate(block->page);
- block->page->private = 0;
+ struct page *page = block->page;
+
+ if (PagePrivate(page)) {
+ ClearPagePrivate(page);
+ page_cache_release(page);
+ set_page_private(page, 0);
+ }
__free_block(sb, block);
}
@@ -650,8 +655,11 @@
logfs_unpack_index(page->index, &bix, &level);
block = __alloc_block(inode->i_sb, inode->i_ino, bix, level);
block->page = page;
+
SetPagePrivate(page);
- page->private = (unsigned long)block;
+ page_cache_get(page);
+ set_page_private(page, (unsigned long) block);
+
block->ops = &indirect_block_ops;
}
@@ -1901,8 +1909,11 @@
li->li_block = block;
block->page = NULL;
- page->private = 0;
- ClearPagePrivate(page);
+ if (PagePrivate(page)) {
+ ClearPagePrivate(page);
+ page_cache_release(page);
+ set_page_private(page, 0);
+ }
}
static void move_inode_to_page(struct page *page, struct inode *inode)
@@ -1918,8 +1929,12 @@
BUG_ON(PagePrivate(page));
block->ops = &indirect_block_ops;
block->page = page;
- page->private = (unsigned long)block;
- SetPagePrivate(page);
+
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ page_cache_get(page);
+ set_page_private(page, (unsigned long) block);
+ }
block->inode = NULL;
li->li_block = NULL;