Commit 1eb643d0 authored Jun 23, 2017 by Jan Kara Committed by Linus Torvalds Jun 23, 2017

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: 9973c98e ("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>

parent 9fa4eb8e

fs/dax.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);

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