From fdac94fab7995ebc52ff9c5b6247133c67a7564a Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Thu, 22 Nov 2018 15:26:01 +0800 Subject: ceph: skip updating 'wanted' caps if caps are already issued When reading cached inode that already has Fscr caps, this can avoid two cap messages (one updats 'wanted' caps, one clears 'wanted' caps). Signed-off-by: "Yan, Zheng" Signed-off-by: Ilya Dryomov --- fs/ceph/caps.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) (limited to 'fs/ceph') diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index e7af6479c9bc..92643b828c50 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -1973,8 +1973,7 @@ retry_locked: goto ack; /* things we might delay */ - if ((cap->issued & ~retain) == 0 && - cap->mds_wanted == want) + if ((cap->issued & ~retain) == 0) continue; /* nope, all good */ if (no_delay) @@ -3051,7 +3050,8 @@ static void handle_cap_grant(struct inode *inode, int used, wanted, dirty; u64 size = le64_to_cpu(grant->size); u64 max_size = le64_to_cpu(grant->max_size); - int check_caps = 0; + unsigned char check_caps = 0; + bool was_stale = cap->cap_gen < session->s_cap_gen; bool wake = false; bool writeback = false; bool queue_trunc = false; @@ -3203,13 +3203,20 @@ static void handle_cap_grant(struct inode *inode, ceph_cap_string(wanted), ceph_cap_string(used), ceph_cap_string(dirty)); - if (wanted != le32_to_cpu(grant->wanted)) { - dout("mds wanted %s -> %s\n", - ceph_cap_string(le32_to_cpu(grant->wanted)), - ceph_cap_string(wanted)); - /* imported cap may not have correct mds_wanted */ - if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) - check_caps = 1; + + if ((was_stale || le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) && + (wanted & ~(cap->mds_wanted | newcaps))) { + /* + * If mds is importing cap, prior cap messages that update + * 'wanted' may get dropped by mds (migrate seq mismatch). + * + * We don't send cap message to update 'wanted' if what we + * want are already issued. If mds revokes caps, cap message + * that releases caps also tells mds what we want. But if + * caps got revoked by mds forcedly (session stale). We may + * haven't told mds what we want. + */ + check_caps = 1; } /* revocation, grant, or no-op? */ -- cgit