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ceph: skip updating 'wanted' caps if caps are already issued

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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" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Yan, Zheng 2018-11-22 15:26:01 +08:00 committed by Ilya Dryomov
parent 8a2ac3a8e9
commit fdac94fab7
1 changed files with 17 additions and 10 deletions
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27
fs/ceph/caps.c
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@ -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? */