From 5e92a168495cd7c8a789004c78313583176e8816 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 28 Oct 2022 10:47:41 -0400 Subject: [PATCH] NFSD: Clean up find_or_add_file() [ Upstream commit 9270fc514ba7d415636b23bcb937573a1ce54f6a ] Remove the call to find_file_locked() in insert_nfs4_file(). Tracing shows that over 99% of these calls return NULL. Thus it is not worth the expense of the extra bucket list traversal. insert_file() already deals correctly with the case where the item is already in the hash bucket. Since nfsd4_file_hash_insert() is now just a wrapper around insert_file(), move the meat of insert_file() into nfsd4_file_hash_insert() and get rid of it. Signed-off-by: Chuck Lever Reviewed-by: NeilBrown Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/nfs4state.c | 68 ++++++++++++++++++++------------------------- 1 file changed, 30 insertions(+), 38 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index c464403c23a2..d2664aa4bde0 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4698,32 +4698,6 @@ find_file_locked(const struct svc_fh *fh, unsigned int hashval) return NULL; } -static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh, - unsigned int hashval) -{ - struct nfs4_file *fp; - struct nfs4_file *ret = NULL; - bool alias_found = false; - - spin_lock(&state_lock); - hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash, - lockdep_is_held(&state_lock)) { - if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) { - if (refcount_inc_not_zero(&fp->fi_ref)) - ret = fp; - } else if (d_inode(fh->fh_dentry) == fp->fi_inode) - fp->fi_aliased = alias_found = true; - } - if (likely(ret == NULL)) { - nfsd4_file_init(fh, new); - hlist_add_head_rcu(&new->fi_hash, &file_hashtbl[hashval]); - new->fi_aliased = alias_found; - ret = new; - } - spin_unlock(&state_lock); - return ret; -} - static struct nfs4_file * find_file(struct svc_fh *fh) { struct nfs4_file *fp; @@ -4735,19 +4709,37 @@ static struct nfs4_file * find_file(struct svc_fh *fh) return fp; } -static struct nfs4_file * -find_or_add_file(struct nfs4_file *new, struct svc_fh *fh) +/* + * On hash insertion, identify entries with the same inode but + * distinct filehandles. They will all be in the same hash bucket + * because nfs4_file's are hashed by the address in the fi_inode + * field. + */ +static noinline_for_stack struct nfs4_file * +nfsd4_file_hash_insert(struct nfs4_file *new, const struct svc_fh *fhp) { - struct nfs4_file *fp; - unsigned int hashval = file_hashval(fh); + unsigned int hashval = file_hashval(fhp); + struct nfs4_file *ret = NULL; + bool alias_found = false; + struct nfs4_file *fi; - rcu_read_lock(); - fp = find_file_locked(fh, hashval); - rcu_read_unlock(); - if (fp) - return fp; - - return insert_file(new, fh, hashval); + spin_lock(&state_lock); + hlist_for_each_entry_rcu(fi, &file_hashtbl[hashval], fi_hash, + lockdep_is_held(&state_lock)) { + if (fh_match(&fi->fi_fhandle, &fhp->fh_handle)) { + if (refcount_inc_not_zero(&fi->fi_ref)) + ret = fi; + } else if (d_inode(fhp->fh_dentry) == fi->fi_inode) + fi->fi_aliased = alias_found = true; + } + if (likely(ret == NULL)) { + nfsd4_file_init(fhp, new); + hlist_add_head_rcu(&new->fi_hash, &file_hashtbl[hashval]); + new->fi_aliased = alias_found; + ret = new; + } + spin_unlock(&state_lock); + return ret; } static noinline_for_stack void nfsd4_file_hash_remove(struct nfs4_file *fi) @@ -5641,7 +5633,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf * and check for delegations in the process of being recalled. * If not found, create the nfs4_file struct */ - fp = find_or_add_file(open->op_file, current_fh); + fp = nfsd4_file_hash_insert(open->op_file, current_fh); if (fp != open->op_file) { status = nfs4_check_deleg(cl, open, &dp); if (status)