From: Ross Zwisler Subject: [PATCH v2 2/9] ext2: tell DAX the size of allocation holes Date: Tue, 23 Aug 2016 16:04:12 -0600 Message-ID: <20160823220419.11717-3-ross.zwisler@linux.intel.com> References: <20160823220419.11717-1-ross.zwisler@linux.intel.com> Cc: Ross Zwisler , "Theodore Ts'o" , Alexander Viro , Andreas Dilger , Andrew Morton , Dan Williams , Dave Chinner , Jan Kara , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, Matthew Wilcox To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <20160823220419.11717-1-ross.zwisler@linux.intel.com> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org When DAX calls ext2_get_block() and the file offset points to a hole we currently don't set bh_result->b_size. When we re-enable PMD faults DAX will need bh_result->b_size to tell it the size of the hole so it can decide whether to fault in a 4 KiB zero page or a 2 MiB zero page. Signed-off-by: Ross Zwisler --- fs/ext2/inode.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index d5c7d09..dd55d74 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -773,6 +773,9 @@ int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_ if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); ret = 0; + } else if (ret == 0) { + /* hole case, need to fill in bh_result->b_size */ + bh_result->b_size = 1 << inode->i_blkbits; } return ret; -- 2.9.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org