fs/dax.c: fix inefficiency in dax_writeback_mapping_range()

dax_writeback_mapping_range() fails to update iteration index when
searching radix tree for entries needing cache flushing.  Thus each
pagevec worth of entries is searched starting from the start which is
inefficient and prone to livelocks.  Update index properly.

Link: http://lkml.kernel.org/r/20170619124531.21491-1-jack@suse.cz
Fixes: 9973c98ecf ("dax: add support for fsync/sync")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Kara 2017-06-23 15:08:46 -07:00 committed by Linus Torvalds
parent 9fa4eb8e49
commit 1eb643d02b

View File

@ -859,6 +859,7 @@ int dax_writeback_mapping_range(struct address_space *mapping,
if (ret < 0)
goto out;
}
start_index = indices[pvec.nr - 1] + 1;
}
out:
put_dax(dax_dev);