From f6e3252e34d8bc6080159a1f2931cb618fe22028 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 22 Mar 2019 12:06:17 +0100 Subject: [PATCH] 4.19-stable patches added patches: bcache-use-req_meta-req_prio-to-indicate-bio-for-metadata.patch --- ...eq_prio-to-indicate-bio-for-metadata.patch | 73 +++++++++++++++++++ queue-4.19/series | 2 +- 2 files changed, 74 insertions(+), 1 deletion(-) create mode 100644 queue-4.19/bcache-use-req_meta-req_prio-to-indicate-bio-for-metadata.patch diff --git a/queue-4.19/bcache-use-req_meta-req_prio-to-indicate-bio-for-metadata.patch b/queue-4.19/bcache-use-req_meta-req_prio-to-indicate-bio-for-metadata.patch new file mode 100644 index 00000000000..340e0907d4b --- /dev/null +++ b/queue-4.19/bcache-use-req_meta-req_prio-to-indicate-bio-for-metadata.patch @@ -0,0 +1,73 @@ +From dc7292a5bcb4c878b076fca2ac3fc22f81b8f8df Mon Sep 17 00:00:00 2001 +From: Coly Li +Date: Sat, 9 Feb 2019 12:53:11 +0800 +Subject: bcache: use (REQ_META|REQ_PRIO) to indicate bio for metadata + +From: Coly Li + +commit dc7292a5bcb4c878b076fca2ac3fc22f81b8f8df upstream. + +In 'commit 752f66a75aba ("bcache: use REQ_PRIO to indicate bio for +metadata")' REQ_META is replaced by REQ_PRIO to indicate metadata bio. +This assumption is not always correct, e.g. XFS uses REQ_META to mark +metadata bio other than REQ_PRIO. This is why Nix noticed that bcache +does not cache metadata for XFS after the above commit. + +Thanks to Dave Chinner, he explains the difference between REQ_META and +REQ_PRIO from view of file system developer. Here I quote part of his +explanation from mailing list, + REQ_META is used for metadata. REQ_PRIO is used to communicate to + the lower layers that the submitter considers this IO to be more + important that non REQ_PRIO IO and so dispatch should be expedited. + + IOWs, if the filesystem considers metadata IO to be more important + that user data IO, then it will use REQ_PRIO | REQ_META rather than + just REQ_META. + +Then it seems bios with REQ_META or REQ_PRIO should both be cached for +performance optimation, because they are all probably low I/O latency +demand by upper layer (e.g. file system). + +So in this patch, when we want to decide whether to bypass the cache, +REQ_META and REQ_PRIO are both checked. Then both metadata and +high priority I/O requests will be handled properly. + +Reported-by: Nix +Signed-off-by: Coly Li +Reviewed-by: Andre Noll +Tested-by: Nix +Cc: stable@vger.kernel.org +Cc: Dave Chinner +Cc: Christoph Hellwig +Signed-off-by: Jens Axboe +Signed-off-by: Greg Kroah-Hartman + +--- + drivers/md/bcache/request.c | 7 ++++--- + 1 file changed, 4 insertions(+), 3 deletions(-) + +--- a/drivers/md/bcache/request.c ++++ b/drivers/md/bcache/request.c +@@ -392,10 +392,11 @@ static bool check_should_bypass(struct c + + /* + * Flag for bypass if the IO is for read-ahead or background, +- * unless the read-ahead request is for metadata (eg, for gfs2). ++ * unless the read-ahead request is for metadata ++ * (eg, for gfs2 or xfs). + */ + if (bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) && +- !(bio->bi_opf & REQ_META)) ++ !(bio->bi_opf & (REQ_META|REQ_PRIO))) + goto skip; + + if (bio->bi_iter.bi_sector & (c->sb.block_size - 1) || +@@ -877,7 +878,7 @@ static int cached_dev_cache_miss(struct + } + + if (!(bio->bi_opf & REQ_RAHEAD) && +- !(bio->bi_opf & REQ_META) && ++ !(bio->bi_opf & (REQ_META|REQ_PRIO)) && + s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA) + reada = min_t(sector_t, dc->readahead >> 9, + get_capacity(bio->bi_disk) - bio_end_sector(bio)); diff --git a/queue-4.19/series b/queue-4.19/series index 28bf26f39b4..356811a3ad7 100644 --- a/queue-4.19/series +++ b/queue-4.19/series @@ -269,7 +269,6 @@ media-imx-csi-stop-upstream-before-disabling-idma-channel.patch drm-fb-helper-generic-fix-drm_fbdev_client_restore.patch drm-radeon-evergreen_cs-fix-missing-break-in-switch-statement.patch drm-amd-powerplay-correct-power-reading-on-fiji.patch -drm-amd-display-add-msse2-to-prevent-clang-from-emitting-libcalls-to-undefined-sw-fp-routines.patch drm-amd-display-don-t-call-dm_pp_-function-from-an-fpu-block.patch kvm-call-kvm_arch_memslots_updated-before-updating-memslots.patch kvm-x86-mmu-detect-mmio-generation-wrap-in-any-address-space.patch @@ -277,3 +276,4 @@ kvm-x86-mmu-do-not-cache-mmio-accesses-while-memslots-are-in-flux.patch kvm-nvmx-sign-extend-displacements-of-vmx-instr-s-mem-operands.patch kvm-nvmx-apply-addr-size-mask-to-effective-address-for-vmx-instructions.patch kvm-nvmx-ignore-limit-checks-on-vmx-instructions-using-flat-segments.patch +bcache-use-req_meta-req_prio-to-indicate-bio-for-metadata.patch -- 2.47.2