Revert "ext4: Fix warnings when freezing filesystem with journaled data"

After making ext4_writepages() properly clean all pages there is no need
for special treatment of filesystem freezing. Revert commit
e6c28a2.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230329154950.19720-13-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Author: jankara

fs/ext4/inode.c

@@ -2385,7 +2385,6 @@ static int mpage_journal_page_buffers(handle_t *handle,
 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 {
 	struct address_space *mapping = mpd->inode->i_mapping;
-	struct super_block *sb = mpd->inode->i_sb;
 	struct folio_batch fbatch;
 	unsigned int nr_folios;
 	pgoff_t index = mpd->first_page;
@@ -2405,15 +2404,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 
 	mpd->map.m_len = 0;
 	mpd->next_page = index;
-	/*
-	 * Start a transaction for writeback of journalled data. We don't start
-	 * the transaction if the filesystem is frozen. In that case we
-	 * should not have any dirty data to write anymore but possibly there
-	 * are stray page dirty bits left by the checkpointing code so this
-	 * loop clears them.
-	 */
-	if (ext4_should_journal_data(mpd->inode) &&
-	    sb->s_writers.frozen < SB_FREEZE_FS) {
+	if (ext4_should_journal_data(mpd->inode)) {
 		handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,
 					    bpp);
 		if (IS_ERR(handle))
@@ -2502,15 +2493,11 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 			 * through a pin.
 			 */
 			if (!mpd->can_map) {
-				WARN_ON_ONCE(sb->s_writers.frozen ==
-					     SB_FREEZE_COMPLETE);
 				err = mpage_submit_folio(mpd, folio);
 				if (err < 0)
 					goto out;
 				/* Pending dirtying of journalled data? */
 				if (folio_test_checked(folio)) {
-					WARN_ON_ONCE(sb->s_writers.frozen >=
-						     SB_FREEZE_FS);
 					err = mpage_journal_page_buffers(handle,
 						mpd, &folio->page);
 					if (err < 0)

fs/ext4/super.c

@@ -6293,17 +6293,6 @@ static int ext4_freeze(struct super_block *sb)
 		if (error < 0)
 			goto out;
 
-		/*
-		 * Do another sync. We really should not have any dirty data
-		 * anymore but our checkpointing code does not clear page dirty
-		 * bits due to locking constraints so writeback still can get
-		 * started for inodes with journalled data which triggers
-		 * annoying warnings.
-		 */
-		error = sync_filesystem(sb);
-		if (error < 0)
-			goto out;
-
 		/* Journal blocked and flushed, clear needs_recovery flag. */
 		ext4_clear_feature_journal_needs_recovery(sb);
 		if (ext4_orphan_file_empty(sb))