Commit 86b0624e authored May 11, 2016 by Jan Kara Committed by Vishal Verma May 17, 2016

ext2: Avoid DAX zeroing to corrupt data



Currently ext2 zeroes any data blocks allocated for DAX inode however it
still returns them as BH_New. Thus DAX code zeroes them again in
dax_insert_mapping() which can possibly overwrite the data that has been
already stored to those blocks by a racing dax_io(). Avoid marking
pre-zeroed buffers as new.

Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>

parent 9b6cd5f7

fs/ext2/inode.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -745,11 +745,11 @@ static int ext2_get_blocks(struct inode *inode,
		mutex_unlock(&ei->truncate_mutex);
		goto cleanup;
		}
		}
		} else
		set_buffer_new(bh_result);

		ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
		mutex_unlock(&ei->truncate_mutex);
		set_buffer_new(bh_result);
		got_it:
		map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
		if (count > blocks_to_boundary)

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