Commit 15baa7dc authored by Zhang Yi's avatar Zhang Yi Committed by Theodore Ts'o
Browse files

ext4: fix warning when submitting superblock in ext4_commit_super() 



We have already check the io_error and uptodate flag before submitting
the superblock buffer, and re-set the uptodate flag if it has been
failed to write out. But it was lockless and could be raced by another
ext4_commit_super(), and finally trigger '!uptodate' WARNING when
marking buffer dirty. Fix it by submit buffer directly.

Reported-by: default avatarHulk Robot <hulkci@huawei.com>
Signed-off-by: default avatarZhang Yi <yi.zhang@huawei.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarRitesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20220520023216.3065073-1-yi.zhang@huawei.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 3103084a

fs/ext4/super.c

+16 −6
Original line number Diff line number Diff line
@@ -5898,7 +5898,6 @@ static void ext4_update_super(struct super_block *sb) 
static int ext4_commit_super(struct super_block *sb)

{

	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;

	int error = 0;



	if (!sbh)

		return -EINVAL;
@@ -5907,6 +5906,13 @@ static int ext4_commit_super(struct super_block *sb) 


	ext4_update_super(sb);



	lock_buffer(sbh);

	/* Buffer got discarded which means block device got invalidated */

	if (!buffer_mapped(sbh)) {

		unlock_buffer(sbh);

		return -EIO;

	}



	if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {

		/*

		 * Oh, dear.  A previous attempt to write the
@@ -5921,17 +5927,21 @@ static int ext4_commit_super(struct super_block *sb) 
		clear_buffer_write_io_error(sbh);

		set_buffer_uptodate(sbh);

	}

	BUFFER_TRACE(sbh, "marking dirty");

	mark_buffer_dirty(sbh);

	error = __sync_dirty_buffer(sbh,

		REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0));

	get_bh(sbh);

	/* Clear potential dirty bit if it was journalled update */

	clear_buffer_dirty(sbh);

	sbh->b_end_io = end_buffer_write_sync;

	submit_bh(REQ_OP_WRITE,

		  REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0), sbh);

	wait_on_buffer(sbh);

	if (buffer_write_io_error(sbh)) {

		ext4_msg(sb, KERN_ERR, "I/O error while writing "

		       "superblock");

		clear_buffer_write_io_error(sbh);

		set_buffer_uptodate(sbh);

		return -EIO;

	}

	return error;

	return 0;

}



/*