f2fs: submit cached bio to avoid endless PageWriteback

When migrating encrypted block from background GC thread, we only add
them into f2fs inner bio cache, but forget to submit the cached bio, it
may cause potential deadlock when we are waiting page writebacked, fix
it.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

3 files changed, 61 insertions, 25 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ff540f523a3b..bf81c60e12b8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2911,7 +2911,7 @@ struct page *f2fs_new_node_page(struct dnode_of_data *dn, unsigned int ofs);
 void f2fs_ra_node_page(struct f2fs_sb_info *sbi, nid_t nid);
 struct page *f2fs_get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid);
 struct page *f2fs_get_node_page_ra(struct page *parent, int start);
-void f2fs_move_node_page(struct page *node_page, int gc_type);
+int f2fs_move_node_page(struct page *node_page, int gc_type);
 int f2fs_fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode,
 			struct writeback_control *wbc, bool atomic,
 			unsigned int *seq_id);
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 78288c54b68c..a07241fb8537 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -473,7 +473,7 @@ static int check_valid_map(struct f2fs_sb_info *sbi,
  * On validity, copy that node with cold status, otherwise (invalid node)
  * ignore that.
  */
-static void gc_node_segment(struct f2fs_sb_info *sbi,
+static int gc_node_segment(struct f2fs_sb_info *sbi,
 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
 {
 	struct f2fs_summary *entry;
@@ -481,6 +481,7 @@ static void gc_node_segment(struct f2fs_sb_info *sbi,
 	int off;
 	int phase = 0;
 	bool fggc = (gc_type == FG_GC);
+	int submitted = 0;
 
 	start_addr = START_BLOCK(sbi, segno);
 
@@ -494,10 +495,11 @@ next_step:
 		nid_t nid = le32_to_cpu(entry->nid);
 		struct page *node_page;
 		struct node_info ni;
+		int err;
 
 		/* stop BG_GC if there is not enough free sections. */
 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
-			return;
+			return submitted;
 
 		if (check_valid_map(sbi, segno, off) == 0)
 			continue;
@@ -534,7 +536,9 @@ next_step:
 			continue;
 		}
 
-		f2fs_move_node_page(node_page, gc_type);
+		err = f2fs_move_node_page(node_page, gc_type);
+		if (!err && gc_type == FG_GC)
+			submitted++;
 		stat_inc_node_blk_count(sbi, 1, gc_type);
 	}
 
@@ -543,6 +547,7 @@ next_step:
 
 	if (fggc)
 		atomic_dec(&sbi->wb_sync_req[NODE]);
+	return submitted;
 }
 
 /*
@@ -678,7 +683,7 @@ put_page:
  * Move data block via META_MAPPING while keeping locked data page.
  * This can be used to move blocks, aka LBAs, directly on disk.
  */
-static void move_data_block(struct inode *inode, block_t bidx,
+static int move_data_block(struct inode *inode, block_t bidx,
 				int gc_type, unsigned int segno, int off)
 {
 	struct f2fs_io_info fio = {
@@ -697,25 +702,29 @@ static void move_data_block(struct inode *inode, block_t bidx,
 	struct node_info ni;
 	struct page *page, *mpage;
 	block_t newaddr;
-	int err;
+	int err = 0;
 	bool lfs_mode = test_opt(fio.sbi, LFS);
 
 	/* do not read out */
 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 	if (!page)
-		return;
+		return -ENOMEM;
 
-	if (!check_valid_map(F2FS_I_SB(inode), segno, off))
+	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
+		err = -ENOENT;
 		goto out;
+	}
 
 	if (f2fs_is_atomic_file(inode)) {
 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
+		err = -EAGAIN;
 		goto out;
 	}
 
 	if (f2fs_is_pinned_file(inode)) {
 		f2fs_pin_file_control(inode, true);
+		err = -EAGAIN;
 		goto out;
 	}
 
@@ -726,6 +735,7 @@ static void move_data_block(struct inode *inode, block_t bidx,
 
 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 		ClearPageUptodate(page);
+		err = -ENOENT;
 		goto put_out;
 	}
 
@@ -808,6 +818,7 @@ write_page:
 	fio.new_blkaddr = newaddr;
 	f2fs_submit_page_write(&fio);
 	if (fio.retry) {
+		err = -EAGAIN;
 		if (PageWriteback(fio.encrypted_page))
 			end_page_writeback(fio.encrypted_page);
 		goto put_page_out;
@@ -831,34 +842,42 @@ put_out:
 	f2fs_put_dnode(&dn);
 out:
 	f2fs_put_page(page, 1);
+	return err;
 }
 
-static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
+static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
 							unsigned int segno, int off)
 {
 	struct page *page;
+	int err = 0;
 
 	page = f2fs_get_lock_data_page(inode, bidx, true);
 	if (IS_ERR(page))
-		return;
+		return PTR_ERR(page);
 
-	if (!check_valid_map(F2FS_I_SB(inode), segno, off))
+	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
+		err = -ENOENT;
 		goto out;
+	}
 
 	if (f2fs_is_atomic_file(inode)) {
 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
+		err = -EAGAIN;
 		goto out;
 	}
 	if (f2fs_is_pinned_file(inode)) {
 		if (gc_type == FG_GC)
 			f2fs_pin_file_control(inode, true);
+		err = -EAGAIN;
 		goto out;
 	}
 
 	if (gc_type == BG_GC) {
-		if (PageWriteback(page))
+		if (PageWriteback(page)) {
+			err = -EAGAIN;
 			goto out;
+		}
 		set_page_dirty(page);
 		set_cold_data(page);
 	} else {
@@ -876,7 +895,6 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
 			.io_type = FS_GC_DATA_IO,
 		};
 		bool is_dirty = PageDirty(page);
-		int err;
 
 retry:
 		set_page_dirty(page);
@@ -901,6 +919,7 @@ retry:
 	}
 out:
 	f2fs_put_page(page, 1);
+	return err;
 }
 
 /*
@@ -910,7 +929,7 @@ out:
  * If the parent node is not valid or the data block address is different,
  * the victim data block is ignored.
  */
-static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
+static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 {
 	struct super_block *sb = sbi->sb;
@@ -918,6 +937,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 	block_t start_addr;
 	int off;
 	int phase = 0;
+	int submitted = 0;
 
 	start_addr = START_BLOCK(sbi, segno);
 
@@ -934,7 +954,7 @@ next_step:
 
 		/* stop BG_GC if there is not enough free sections. */
 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
-			return;
+			return submitted;
 
 		if (check_valid_map(sbi, segno, off) == 0)
 			continue;
@@ -1006,6 +1026,7 @@ next_step:
 		if (inode) {
 			struct f2fs_inode_info *fi = F2FS_I(inode);
 			bool locked = false;
+			int err;
 
 			if (S_ISREG(inode->i_mode)) {
 				if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
@@ -1025,12 +1046,16 @@ next_step:
 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
 								+ ofs_in_node;
 			if (f2fs_post_read_required(inode))
-				move_data_block(inode, start_bidx, gc_type,
-								segno, off);
+				err = move_data_block(inode, start_bidx,
+							gc_type, segno, off);
 			else
-				move_data_page(inode, start_bidx, gc_type,
+				err = move_data_page(inode, start_bidx, gc_type,
 								segno, off);
 
+			if (!err && (gc_type == FG_GC ||
+					f2fs_post_read_required(inode)))
+				submitted++;
+
 			if (locked) {
 				up_write(&fi->i_gc_rwsem[WRITE]);
 				up_write(&fi->i_gc_rwsem[READ]);
@@ -1042,6 +1067,8 @@ next_step:
 
 	if (++phase < 5)
 		goto next_step;
+
+	return submitted;
 }
 
 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
@@ -1069,6 +1096,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 	int seg_freed = 0;
 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 						SUM_TYPE_DATA : SUM_TYPE_NODE;
+	int submitted = 0;
 
 	/* readahead multi ssa blocks those have contiguous address */
 	if (sbi->segs_per_sec > 1)
@@ -1124,10 +1152,11 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 		 *                                  - lock_page(sum_page)
 		 */
 		if (type == SUM_TYPE_NODE)
-			gc_node_segment(sbi, sum->entries, segno, gc_type);
-		else
-			gc_data_segment(sbi, sum->entries, gc_list, segno,
+			submitted += gc_node_segment(sbi, sum->entries, segno,
 								gc_type);
+		else
+			submitted += gc_data_segment(sbi, sum->entries, gc_list,
+							segno, gc_type);
 
 		stat_inc_seg_count(sbi, type, gc_type);
 
@@ -1138,7 +1167,7 @@ next:
 		f2fs_put_page(sum_page, 0);
 	}
 
-	if (gc_type == FG_GC)
+	if (submitted)
 		f2fs_submit_merged_write(sbi,
 				(type == SUM_TYPE_NODE) ? NODE : DATA);
 
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index b1e3ff8147f6..8f5719767178 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1587,8 +1587,10 @@ redirty_out:
 	return AOP_WRITEPAGE_ACTIVATE;
 }
 
-void f2fs_move_node_page(struct page *node_page, int gc_type)
+int f2fs_move_node_page(struct page *node_page, int gc_type)
 {
+	int err = 0;
+
 	if (gc_type == FG_GC) {
 		struct writeback_control wbc = {
 			.sync_mode = WB_SYNC_ALL,
@@ -1600,12 +1602,16 @@ void f2fs_move_node_page(struct page *node_page, int gc_type)
 		f2fs_wait_on_page_writeback(node_page, NODE, true);
 
 		f2fs_bug_on(F2FS_P_SB(node_page), PageWriteback(node_page));
-		if (!clear_page_dirty_for_io(node_page))
+		if (!clear_page_dirty_for_io(node_page)) {
+			err = -EAGAIN;
 			goto out_page;
+		}
 
 		if (__write_node_page(node_page, false, NULL,
-					&wbc, false, FS_GC_NODE_IO, NULL))
+					&wbc, false, FS_GC_NODE_IO, NULL)) {
+			err = -EAGAIN;
 			unlock_page(node_page);
+		}
 		goto release_page;
 	} else {
 		/* set page dirty and write it */
@@ -1616,6 +1622,7 @@ out_page:
 	unlock_page(node_page);
 release_page:
 	f2fs_put_page(node_page, 0);
+	return err;
 }
 
 static int f2fs_write_node_page(struct page *page,