From: J.Bruce Fields Date: Wed, 13 Dec 2006 08:35:25 +0000 (-0800) Subject: [PATCH] knfsd: nfsd: don't drop silently on upcall deferral X-Git-Tag: v2.6.20-rc1~57 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e0bb89ef031f76dcb9c9d920d18b13948f1418da;p=linux-2.6 [PATCH] knfsd: nfsd: don't drop silently on upcall deferral To avoid tying up server threads when nfsd makes an upcall (to mountd, to get export options, to idmapd, for nfsv4 name<->id mapping, etc.), we temporarily "drop" the request and save enough information so that we can revisit it later. Certain failures during the deferral process can cause us to really drop the request and never revisit it. This is often less than ideal, and is unacceptable in the NFSv4 case--rfc 3530 forbids the server from dropping a request without also closing the connection. As a first step, we modify the deferral code to return -ETIMEDOUT (which is translated to nfserr_jukebox in the v3 and v4 cases, and remains a drop in the v2 case). Signed-off-by: J. Bruce Fields Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index b0591cd172..1137d09c59 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -787,15 +787,20 @@ exp_get_by_name(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry, key.ex_dentry = dentry; exp = svc_export_lookup(&key); - if (exp != NULL) - switch (cache_check(&svc_export_cache, &exp->h, reqp)) { + if (exp != NULL) { + int err; + + err = cache_check(&svc_export_cache, &exp->h, reqp); + switch (err) { case 0: break; case -EAGAIN: - exp = ERR_PTR(-EAGAIN); + case -ETIMEDOUT: + exp = ERR_PTR(err); break; default: exp = NULL; } + } return exp; } diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index 727ab3bd45..b06bf9f70e 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -169,9 +169,11 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle); } - error = nfserr_dropit; - if (IS_ERR(exp) && PTR_ERR(exp) == -EAGAIN) + if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN + || PTR_ERR(exp) == -ETIMEDOUT)) { + error = nfserrno(PTR_ERR(exp)); goto out; + } error = nfserr_stale; if (!exp || IS_ERR(exp)) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 4883d75862..7a79c23aa6 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -99,7 +99,7 @@ static struct raparm_hbucket raparm_hash[RAPARM_HASH_SIZE]; /* * Called from nfsd_lookup and encode_dirent. Check if we have crossed * a mount point. - * Returns -EAGAIN leaving *dpp and *expp unchanged, + * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged, * or nfs_ok having possibly changed *dpp and *expp */ int diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 3bf3520f92..066c64a97f 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -1066,7 +1066,7 @@ svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp) } switch(cache_check(&rsi_cache, &rsip->h, &rqstp->rq_chandle)) { case -EAGAIN: - goto drop; + case -ETIMEDOUT: case -ENOENT: goto drop; case 0: diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 80aff04745..824e8534e0 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -34,7 +34,7 @@ #define RPCDBG_FACILITY RPCDBG_CACHE -static void cache_defer_req(struct cache_req *req, struct cache_head *item); +static int cache_defer_req(struct cache_req *req, struct cache_head *item); static void cache_revisit_request(struct cache_head *item); static void cache_init(struct cache_head *h) @@ -185,6 +185,7 @@ static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h); * * Returns 0 if the cache_head can be used, or cache_puts it and returns * -EAGAIN if upcall is pending, + * -ETIMEDOUT if upcall failed and should be retried, * -ENOENT if cache entry was negative */ int cache_check(struct cache_detail *detail, @@ -236,7 +237,8 @@ int cache_check(struct cache_detail *detail, } if (rv == -EAGAIN) - cache_defer_req(rqstp, h); + if (cache_defer_req(rqstp, h) != 0) + rv = -ETIMEDOUT; if (rv) cache_put(h, detail); @@ -523,14 +525,14 @@ static LIST_HEAD(cache_defer_list); static struct list_head cache_defer_hash[DFR_HASHSIZE]; static int cache_defer_cnt; -static void cache_defer_req(struct cache_req *req, struct cache_head *item) +static int cache_defer_req(struct cache_req *req, struct cache_head *item) { struct cache_deferred_req *dreq; int hash = DFR_HASH(item); dreq = req->defer(req); if (dreq == NULL) - return; + return -ETIMEDOUT; dreq->item = item; dreq->recv_time = get_seconds(); @@ -571,6 +573,7 @@ static void cache_defer_req(struct cache_req *req, struct cache_head *item) /* must have just been validated... */ cache_revisit_request(item); } + return 0; } static void cache_revisit_request(struct cache_head *item) diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index a0a953a430..177f81608c 100644 --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -435,6 +435,7 @@ svcauth_unix_set_client(struct svc_rqst *rqstp) default: BUG(); case -EAGAIN: + case -ETIMEDOUT: return SVC_DROP; case -ENOENT: return SVC_DENIED;