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Commit cf37e972 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

writeback: enforce s_umount locking in writeback_inodes_sb 



Make sure that not only sync_filesystem but all callers of writeback_inodes_sb
have the superblock protected against remount.  As-is this disables all
functionality for these callers, but the next patch relies on this locking to
fix writeback_inodes_sb for sync_filesystem.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 3c4d7165

fs/fs-writeback.c

+6 −0
Original line number Diff line number Diff line
@@ -1180,6 +1180,8 @@ void writeback_inodes_sb(struct super_block *sb) 
		.sync_mode	= WB_SYNC_NONE,

	};



	WARN_ON(!rwsem_is_locked(&sb->s_umount));



	args.nr_pages = nr_dirty + nr_unstable +

			(inodes_stat.nr_inodes - inodes_stat.nr_unused);
@@ -1197,7 +1199,9 @@ EXPORT_SYMBOL(writeback_inodes_sb); 
int writeback_inodes_sb_if_idle(struct super_block *sb)

{

	if (!writeback_in_progress(sb->s_bdi)) {

		down_read(&sb->s_umount);

		writeback_inodes_sb(sb);

		up_read(&sb->s_umount);

		return 1;

	} else

		return 0;
@@ -1220,6 +1224,8 @@ void sync_inodes_sb(struct super_block *sb) 
		.range_cyclic	= 0,

	};



	WARN_ON(!rwsem_is_locked(&sb->s_umount));



	bdi_queue_work_onstack(&args);

	wait_sb_inodes(sb);

}

fs/ubifs/budget.c

+2 −0
Original line number Diff line number Diff line
@@ -62,7 +62,9 @@ 
 */

static void shrink_liability(struct ubifs_info *c, int nr_to_write)

{

	down_read(&c->vfs_sb->s_umount);

	writeback_inodes_sb(c->vfs_sb);

	up_read(&c->vfs_sb->s_umount);

}



/**