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;
diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c
index 9d51873..6aee609 100644
--- a/fs/logfs/segment.c
+++ b/fs/logfs/segment.c
@@ -86,7 +86,11 @@
BUG_ON(!page); /* FIXME: reserve a pool */
SetPageUptodate(page);
memcpy(page_address(page) + offset, buf, copylen);
- SetPagePrivate(page);
+
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ page_cache_get(page);
+ }
page_cache_release(page);
buf += copylen;
@@ -110,7 +114,10 @@
page = get_mapping_page(sb, index, 0);
BUG_ON(!page); /* FIXME: reserve a pool */
memset(page_address(page) + offset, 0xff, len);
- SetPagePrivate(page);
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ page_cache_get(page);
+ }
page_cache_release(page);
}
}
@@ -130,7 +137,10 @@
BUG_ON(!page); /* FIXME: reserve a pool */
SetPageUptodate(page);
memset(page_address(page), 0xff, PAGE_CACHE_SIZE);
- SetPagePrivate(page);
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ page_cache_get(page);
+ }
page_cache_release(page);
index++;
no_indizes--;
@@ -485,8 +495,12 @@
mempool_free(item, super->s_alias_pool);
}
block->page = page;
- SetPagePrivate(page);
- page->private = (unsigned long)block;
+
+ if (!PagePrivate(page)) {
+ SetPagePrivate(page);
+ page_cache_get(page);
+ set_page_private(page, (unsigned long) block);
+ }
block->ops = &indirect_block_ops;
initialize_block_counters(page, block, data, 0);
}
@@ -536,8 +550,12 @@
list_add(&item->list, &block->item_list);
}
block->page = NULL;
- ClearPagePrivate(page);
- page->private = 0;
+
+ if (PagePrivate(page)) {
+ ClearPagePrivate(page);
+ page_cache_release(page);
+ set_page_private(page, 0);
+ }
block->ops = &btree_block_ops;
err = alias_tree_insert(block->sb, block->ino, block->bix, block->level,
block);
@@ -702,7 +720,10 @@
page = find_get_page(mapping, ofs >> PAGE_SHIFT);
if (!page)
continue;
- ClearPagePrivate(page);
+ if (PagePrivate(page)) {
+ ClearPagePrivate(page);
+ page_cache_release(page);
+ }
page_cache_release(page);
}
}