On 2 March 2012 00:03, Ted Ts'o <tytso@xxxxxxx> wrote: > On Thu, Mar 01, 2012 at 11:41:03PM +0530, Saugata Das wrote: >> From: Saugata Das <saugata.das@xxxxxxxxxx> >> >> Today, storage devices like eMMC has special features like data tagging >> (introduced in MMC-4.5 version) in order to improve performance of some >> specific writes. On MMC stack, data tagging is used for all writes which has >> REQ_META flag set. On EXT4, however, currently REQ_META is set only for read. >> This patch adds the capability to add REQ_META flag during meta data write. >> This patch adds new function set_buffer_meta, which is used to set a bit >> BH_Meta in the b_state field when meta data and super block is made dirty. >> >> --- a/fs/buffer.c >> +++ b/fs/buffer.c >> @@ -2926,6 +2926,9 @@ int submit_bh(int rw, struct buffer_head * bh) >> if (test_set_buffer_req(bh) && (rw & WRITE)) >> clear_buffer_write_io_error(bh); >> >> + if (buffer_meta(bh) && (rw & WRITE)) >> + rw |= REQ_META; >> + > > I know it's not necessary for your purposes as stated in the commit > description, but wouldn't it be better if buffer_meta() always caused > REQ_META to be set, regardless of whether we are doing a read or a > write? Sure, I will modify this in the next version. > > - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
