Merge tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream

There are few important bug fixes for LogFS

* tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream:
  Logfs: Allow NULL block_isbad() methods
  logfs: Grow inode in delete path
  logfs: Free areas before calling generic_shutdown_super()
  logfs: remove useless BUG_ON
  MAINTAINERS: Add Prasad Joshi in LogFS maintiners
  logfs: Propagate page parameter to __logfs_write_inode
  logfs: set superblock shutdown flag after generic sb shutdown
  logfs: take write mutex lock during fsync and sync
  logfs: Prevent memory corruption
  logfs: update page reference count for pined pages

Fix up conflict in fs/logfs/dev_mtd.c due to semantic change in what
"mtd->block_isbad" means in commit f2933e86ad93: "Logfs: Allow NULL
block_isbad() methods" clashing with the abstraction changes in the
commits 7086c19d0742: "mtd: introduce mtd_block_isbad interface" and
d58b27ed58a3: "logfs: do not use 'mtd->block_isbad' directly".

This resolution takes the semantics from commit f2933e86ad93, and just
makes mtd_block_isbad() return zero (false) if the 'block_isbad'
function is NULL.  But that also means that now "mtd_can_have_bb()"
always returns 0.

Now, "mtd_block_markbad()" will obviously return an error if the
low-level driver doesn't support bad blocks, so this is somewhat
non-symmetric, but it actually makes sense if a NULL "block_isbad"
function is considered to mean "I assume that all my blocks are always
good".

1 files changed, 39 insertions, 12 deletions

diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c
index 9d5187353255..ab798ed1cc88 100644
--- a/fs/logfs/segment.c
+++ b/fs/logfs/segment.c
@@ -86,7 +86,11 @@ int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
 		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 @@ static void pad_partial_page(struct logfs_area *area)
 		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 @@ static void pad_full_pages(struct logfs_area *area)
 		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 @@ static void move_btree_to_page(struct inode *inode, struct page *page,
 		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 @@ void move_page_to_btree(struct page *page)
 		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 @@ void freeseg(struct super_block *sb, u32 segno)
 		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);
 	}
 }
@@ -841,6 +862,16 @@ static void free_area(struct logfs_area *area)
 	kfree(area);
 }
 
+void free_areas(struct super_block *sb)
+{
+	struct logfs_super *super = logfs_super(sb);
+	int i;
+
+	for_each_area(i)
+		free_area(super->s_area[i]);
+	free_area(super->s_journal_area);
+}
+
 static struct logfs_area *alloc_area(struct super_block *sb)
 {
 	struct logfs_area *area;
@@ -923,10 +954,6 @@ err:
 void logfs_cleanup_areas(struct super_block *sb)
 {
 	struct logfs_super *super = logfs_super(sb);
-	int i;
 
 	btree_grim_visitor128(&super->s_object_alias_tree, 0, kill_alias);
-	for_each_area(i)
-		free_area(super->s_area[i]);
-	free_area(super->s_journal_area);
 }