f2fs: support get_page error injection

This patch adds to support get_page error injection to simulate
out-of-memory test scenario.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1965,7 +1965,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 	 * Do not use grab_cache_page_write_begin() to avoid deadlock due to
 	 * wait_for_stable_page. Will wait that below with our IO control.
 	 */
-	page = pagecache_get_page(mapping, index,
+	page = f2fs_pagecache_get_page(mapping, index,
 				FGP_LOCK | FGP_WRITE | FGP_CREAT, GFP_NOFS);
 	if (!page) {
 		err = -ENOMEM;

fs/f2fs/f2fs.h

@@ -46,6 +46,7 @@
 enum {
 	FAULT_KMALLOC,
 	FAULT_PAGE_ALLOC,
+	FAULT_PAGE_GET,
 	FAULT_ALLOC_NID,
 	FAULT_ORPHAN,
 	FAULT_BLOCK,
@@ -1835,6 +1836,19 @@ static inline struct page *f2fs_grab_cache_page(struct address_space *mapping,
 	return grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
 }
 
+static inline struct page *f2fs_pagecache_get_page(
+				struct address_space *mapping, pgoff_t index,
+				int fgp_flags, gfp_t gfp_mask)
+{
+#ifdef CONFIG_F2FS_FAULT_INJECTION
+	if (time_to_inject(F2FS_M_SB(mapping), FAULT_PAGE_GET)) {
+		f2fs_show_injection_info(FAULT_PAGE_GET);
+		return NULL;
+	}
+#endif
+	return pagecache_get_page(mapping, index, fgp_flags, gfp_mask);
+}
+
 static inline void f2fs_copy_page(struct page *src, struct page *dst)
 {
 	char *src_kaddr = kmap(src);

fs/f2fs/gc.c

@@ -650,8 +650,8 @@ static void move_data_block(struct inode *inode, block_t bidx,
 	allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 					&sum, CURSEG_COLD_DATA, NULL, false);
 
-	fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
-					FGP_LOCK | FGP_CREAT, GFP_NOFS);
+	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
+				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
 	if (!fio.encrypted_page) {
 		err = -ENOMEM;
 		goto recover_block;

fs/f2fs/node.c

@@ -1218,7 +1218,8 @@ static void flush_inline_data(struct f2fs_sb_info *sbi, nid_t ino)
 	if (!inode)
 		return;
 
-	page = pagecache_get_page(inode->i_mapping, 0, FGP_LOCK|FGP_NOWAIT, 0);
+	page = f2fs_pagecache_get_page(inode->i_mapping, 0,
+					FGP_LOCK|FGP_NOWAIT, 0);
 	if (!page)
 		goto iput_out;
 

fs/f2fs/super.c

@@ -44,6 +44,7 @@ static struct kmem_cache *f2fs_inode_cachep;
 char *fault_name[FAULT_MAX] = {
 	[FAULT_KMALLOC]		= "kmalloc",
 	[FAULT_PAGE_ALLOC]	= "page alloc",
+	[FAULT_PAGE_GET]	= "page get",
 	[FAULT_ALLOC_NID]	= "alloc nid",
 	[FAULT_ORPHAN]		= "orphan",
 	[FAULT_BLOCK]		= "no more block",