4 files changed, 86 insertions, 23 deletions

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 6b49f14eac8c..ba7a1da7634b 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -175,6 +175,11 @@ static int nilfs_writepages(struct address_space *mapping,
 	struct inode *inode = mapping->host;
 	int err = 0;
 
+	if (inode->i_sb->s_flags & MS_RDONLY) {
+		nilfs_clear_dirty_pages(mapping, false);
+		return -EROFS;
+	}
+
 	if (wbc->sync_mode == WB_SYNC_ALL)
 		err = nilfs_construct_dsync_segment(inode->i_sb, inode,
 						    wbc->range_start,
@@ -187,6 +192,18 @@ static int nilfs_writepage(struct page *page, struct writeback_control *wbc)
 	struct inode *inode = page->mapping->host;
 	int err;
 
+	if (inode && (inode->i_sb->s_flags & MS_RDONLY)) {
+		/*
+		 * It means that filesystem was remounted in read-only
+		 * mode because of error or metadata corruption. But we
+		 * have dirty pages that try to be flushed in background.
+		 * So, here we simply discard this dirty page.
+		 */
+		nilfs_clear_dirty_page(page, false);
+		unlock_page(page);
+		return -EROFS;
+	}
+
 	redirty_page_for_writepage(wbc, page);
 	unlock_page(page);
 
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index f9897d09c693..c4dcd1db57ee 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -375,14 +375,25 @@ int nilfs_mdt_fetch_dirty(struct inode *inode)
 static int
 nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 {
-	struct inode *inode;
+	struct inode *inode = page->mapping->host;
 	struct super_block *sb;
 	int err = 0;
 
+	if (inode && (inode->i_sb->s_flags & MS_RDONLY)) {
+		/*
+		 * It means that filesystem was remounted in read-only
+		 * mode because of error or metadata corruption. But we
+		 * have dirty pages that try to be flushed in background.
+		 * So, here we simply discard this dirty page.
+		 */
+		nilfs_clear_dirty_page(page, false);
+		unlock_page(page);
+		return -EROFS;
+	}
+
 	redirty_page_for_writepage(wbc, page);
 	unlock_page(page);
 
-	inode = page->mapping->host;
 	if (!inode)
 		return 0;
 
@@ -561,10 +572,10 @@ void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
 	if (mi->mi_palloc_cache)
 		nilfs_palloc_clear_cache(inode);
 
-	nilfs_clear_dirty_pages(inode->i_mapping);
+	nilfs_clear_dirty_pages(inode->i_mapping, true);
 	nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
 
-	nilfs_clear_dirty_pages(&ii->i_btnode_cache);
+	nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
 	nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
 
 	nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index 07f76db04ec7..131a5841a070 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -370,7 +370,12 @@ repeat:
 	goto repeat;
 }
 
-void nilfs_clear_dirty_pages(struct address_space *mapping)
+/**
+ * nilfs_clear_dirty_pages - discard dirty pages in address space
+ * @mapping: address space with dirty pages for discarding
+ * @silent: suppress [true] or print [false] warning messages
+ */
+void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
 {
 	struct pagevec pvec;
 	unsigned int i;
@@ -382,25 +387,9 @@ void nilfs_clear_dirty_pages(struct address_space *mapping)
 				  PAGEVEC_SIZE)) {
 		for (i = 0; i < pagevec_count(&pvec); i++) {
 			struct page *page = pvec.pages[i];
-			struct buffer_head *bh, *head;
 
 			lock_page(page);
-			ClearPageUptodate(page);
-			ClearPageMappedToDisk(page);
-			bh = head = page_buffers(page);
-			do {
-				lock_buffer(bh);
-				clear_buffer_dirty(bh);
-				clear_buffer_nilfs_volatile(bh);
-				clear_buffer_nilfs_checked(bh);
-				clear_buffer_nilfs_redirected(bh);
-				clear_buffer_uptodate(bh);
-				clear_buffer_mapped(bh);
-				unlock_buffer(bh);
-				bh = bh->b_this_page;
-			} while (bh != head);
-
-			__nilfs_clear_page_dirty(page);
+			nilfs_clear_dirty_page(page, silent);
 			unlock_page(page);
 		}
 		pagevec_release(&pvec);
@@ -408,6 +397,51 @@ void nilfs_clear_dirty_pages(struct address_space *mapping)
 	}
 }
 
+/**
+ * nilfs_clear_dirty_page - discard dirty page
+ * @page: dirty page that will be discarded
+ * @silent: suppress [true] or print [false] warning messages
+ */
+void nilfs_clear_dirty_page(struct page *page, bool silent)
+{
+	struct inode *inode = page->mapping->host;
+	struct super_block *sb = inode->i_sb;
+
+	BUG_ON(!test_bit(PG_locked, &page->flags));
+
+	if (!silent) {
+		nilfs_warning(sb, __func__,
+				"discard page: offset %lld, ino %lu",
+				page_offset(page), inode->i_ino);
+	}
+
+	ClearPageUptodate(page);
+	ClearPageMappedToDisk(page);
+
+	if (page_has_buffers(page)) {
+		struct buffer_head *bh, *head;
+
+		bh = head = page_buffers(page);
+		do {
+			lock_buffer(bh);
+			if (!silent) {
+				nilfs_warning(sb, __func__,
+					"discard block %llu, size %zu",
+					(u64)bh->b_blocknr, bh->b_size);
+			}
+			clear_buffer_dirty(bh);
+			clear_buffer_nilfs_volatile(bh);
+			clear_buffer_nilfs_checked(bh);
+			clear_buffer_nilfs_redirected(bh);
+			clear_buffer_uptodate(bh);
+			clear_buffer_mapped(bh);
+			unlock_buffer(bh);
+		} while (bh = bh->b_this_page, bh != head);
+	}
+
+	__nilfs_clear_page_dirty(page);
+}
+
 unsigned nilfs_page_count_clean_buffers(struct page *page,
 					unsigned from, unsigned to)
 {
diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h
index fb7de71605a0..ef30c5c2426f 100644
--- a/fs/nilfs2/page.h
+++ b/fs/nilfs2/page.h
@@ -55,7 +55,8 @@ void nilfs_page_bug(struct page *);
 
 int nilfs_copy_dirty_pages(struct address_space *, struct address_space *);
 void nilfs_copy_back_pages(struct address_space *, struct address_space *);
-void nilfs_clear_dirty_pages(struct address_space *);
+void nilfs_clear_dirty_page(struct page *, bool);
+void nilfs_clear_dirty_pages(struct address_space *, bool);
 void nilfs_mapping_init(struct address_space *mapping, struct inode *inode,
 			struct backing_dev_info *bdi);
 unsigned nilfs_page_count_clean_buffers(struct page *, unsigned, unsigned);