| Message ID | 1543376991-5764-5-git-send-email-allison.henderson@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Block/XFS: Support alternative mirror device retry | expand |
On Tue, Nov 27, 2018 at 08:49:48PM -0700, Allison Henderson wrote: > This patch adds a new field b_rw_hint to xfs_buf. We will > need this to properly initialize the new bio->bi_rw_hint when > submitting the read request. When the read completes, we > then store the returned mirror in the b_rw_hint. > > Signed-off-by: Allison Henderson <allison.henderson@oracle.com> > --- > fs/xfs/xfs_buf.c | 5 ++++- > fs/xfs/xfs_buf.h | 7 +++++++ > 2 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > index b21ea2b..dd8ba59 100644 > --- a/fs/xfs/xfs_buf.c > +++ b/fs/xfs/xfs_buf.c > @@ -1322,8 +1322,10 @@ xfs_buf_bio_end_io( > if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ)) > invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp)); > > - if (atomic_dec_and_test(&bp->b_io_remaining) == 1) > + if (atomic_dec_and_test(&bp->b_io_remaining) == 1) { > + bp->b_rw_hint = bio->bi_rw_hint; > xfs_buf_ioend_async(bp); > + } > bio_put(bio); > } > This will miss setting bp->b_rw_hint for IO that completes before submission returns to __xfs_buf_submit() (i.e. b_io_remaining is 2 at IO completion). So I suspect it won't do the right thing on fast or synchronous block devices like pmem. You should be able to tst this with a RAID1 made from two ramdisks... Cheers, Dave.
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index b21ea2b..dd8ba59 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -1322,8 +1322,10 @@ xfs_buf_bio_end_io( if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ)) invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp)); - if (atomic_dec_and_test(&bp->b_io_remaining) == 1) + if (atomic_dec_and_test(&bp->b_io_remaining) == 1) { + bp->b_rw_hint = bio->bi_rw_hint; xfs_buf_ioend_async(bp); + } bio_put(bio); } @@ -1369,6 +1371,7 @@ xfs_buf_ioapply_map( bio->bi_iter.bi_sector = sector; bio->bi_end_io = xfs_buf_bio_end_io; bio->bi_private = bp; + bio->bi_rw_hint = bp->b_rw_hint; bio_set_op_attrs(bio, op, op_flags); for (; size && nr_pages; nr_pages--, page_index++) { diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h index b9f5511..db138e5 100644 --- a/fs/xfs/xfs_buf.h +++ b/fs/xfs/xfs_buf.h @@ -197,6 +197,13 @@ typedef struct xfs_buf { unsigned long b_first_retry_time; /* in jiffies */ int b_last_error; + /* + * If b_rw_hint is set before a read, it specifies an alternate mirror + * to read from. Upon bio completion, b_rw_hint stores the last mirror + * that was read from + */ + unsigned short b_rw_hint; + const struct xfs_buf_ops *b_ops; } xfs_buf_t;
This patch adds a new field b_rw_hint to xfs_buf. We will need this to properly initialize the new bio->bi_rw_hint when submitting the read request. When the read completes, we then store the returned mirror in the b_rw_hint. Signed-off-by: Allison Henderson <allison.henderson@oracle.com> --- fs/xfs/xfs_buf.c | 5 ++++- fs/xfs/xfs_buf.h | 7 +++++++ 2 files changed, 11 insertions(+), 1 deletion(-)