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nfsd: clean up and clarify the cache expiration code

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Add a preprocessor constant for the expiry time of cache entries, and
move the test for an expired entry into a function. Note that the current
code does not test for RC_INPROG. It just assumes that it won't take more
than 2 minutes to fill out an in-progress entry.

I'm not sure how valid that assumption is though, so let's just ensure
that we never consider an RC_INPROG entry to be expired.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Jeff Layton 2013-01-28 14:41:13 -05:00 committed by J. Bruce Fields
parent 25e6b8b0e1
commit d1a0774de6
2 changed files with 11 additions and 1 deletions
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3
fs/nfsd/cache.h
View File

@ -70,6 +70,9 @@ enum {
*/
#define RC_DELAY (HZ/5)
/* Cache entries expire after this time period */
#define RC_EXPIRE (120 * HZ)
int nfsd_reply_cache_init(void);
void nfsd_reply_cache_shutdown(void);
int nfsd_cache_lookup(struct svc_rqst *);

9
fs/nfsd/nfscache.c
View File

@ -142,6 +142,13 @@ hash_refile(struct svc_cacherep *rp)
hlist_add_head(&rp->c_hash, cache_hash + request_hash(rp->c_xid));
}
static inline bool
nfsd_cache_entry_expired(struct svc_cacherep *rp)
{
return rp->c_state != RC_INPROG &&
time_after(jiffies, rp->c_timestamp + RC_EXPIRE);
}
/*
* Try to find an entry matching the current call in the cache. When none
* is found, we grab the oldest unlocked entry off the LRU list.
@ -175,7 +182,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
if (rp->c_state != RC_UNUSED &&
xid == rp->c_xid && proc == rp->c_proc &&
proto == rp->c_prot && vers == rp->c_vers &&
time_before(jiffies, rp->c_timestamp + 120*HZ) &&
!nfsd_cache_entry_expired(rp) &&
rpc_cmp_addr(svc_addr(rqstp), (struct sockaddr *)&rp->c_addr) &&
rpc_get_port(svc_addr(rqstp)) == rpc_get_port((struct sockaddr *)&rp->c_addr)) {
nfsdstats.rchits++;