6.1-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ 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 chuck.lever@oracle.com Reviewed-by: NeilBrown neilb@suse.de Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/nfs4state.c | 64 ++++++++++++++++++++++------------------------------ 1 file changed, 28 insertions(+), 36 deletions(-)
--- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4699,24 +4699,42 @@ find_file_locked(const struct svc_fh *fh return NULL; }
-static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh, - unsigned int hashval) +static struct nfs4_file * find_file(struct svc_fh *fh) { struct nfs4_file *fp; + unsigned int hashval = file_hashval(fh); + + rcu_read_lock(); + fp = find_file_locked(fh, hashval); + rcu_read_unlock(); + return fp; +} + +/* + * 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) +{ + unsigned int hashval = file_hashval(fhp); struct nfs4_file *ret = NULL; bool alias_found = false; + struct nfs4_file *fi;
spin_lock(&state_lock); - hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash, + hlist_for_each_entry_rcu(fi, &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 (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(fh, new); + nfsd4_file_init(fhp, new); hlist_add_head_rcu(&new->fi_hash, &file_hashtbl[hashval]); new->fi_aliased = alias_found; ret = new; @@ -4725,32 +4743,6 @@ static struct nfs4_file *insert_file(str return ret; }
-static struct nfs4_file * find_file(struct svc_fh *fh) -{ - struct nfs4_file *fp; - unsigned int hashval = file_hashval(fh); - - rcu_read_lock(); - fp = find_file_locked(fh, hashval); - rcu_read_unlock(); - return fp; -} - -static struct nfs4_file * -find_or_add_file(struct nfs4_file *new, struct svc_fh *fh) -{ - struct nfs4_file *fp; - unsigned int hashval = file_hashval(fh); - - rcu_read_lock(); - fp = find_file_locked(fh, hashval); - rcu_read_unlock(); - if (fp) - return fp; - - return insert_file(new, fh, hashval); -} - static noinline_for_stack void nfsd4_file_hash_remove(struct nfs4_file *fi) { hlist_del_rcu(&fi->fi_hash); @@ -5661,7 +5653,7 @@ nfsd4_process_open2(struct svc_rqst *rqs * 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)