From patchwork Tue Oct 16 22:01:31 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bruce Fields X-Patchwork-Id: 1602761 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 961013FCFC for ; Tue, 16 Oct 2012 22:02:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755563Ab2JPWCJ (ORCPT ); Tue, 16 Oct 2012 18:02:09 -0400 Received: from fieldses.org ([174.143.236.118]:36019 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755013Ab2JPWBn (ORCPT ); Tue, 16 Oct 2012 18:01:43 -0400 Received: from bfields by fieldses.org with local (Exim 4.76) (envelope-from ) id 1TOFCo-00071b-3y; Tue, 16 Oct 2012 18:01:42 -0400 From: "J. Bruce Fields" To: Al Viro Cc: linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, "J. Bruce Fields" Subject: [PATCH 06/12] locks: implement delegations Date: Tue, 16 Oct 2012 18:01:31 -0400 Message-Id: <1350424897-26894-7-git-send-email-bfields@redhat.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1350424897-26894-1-git-send-email-bfields@redhat.com> References: <1350424897-26894-1-git-send-email-bfields@redhat.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: "J. Bruce Fields" Implement NFSv4 delegations at the vfs level using the new FL_DELEG lock type. Signed-off-by: J. Bruce Fields --- fs/locks.c | 49 +++++++++++++++++++++++++++++++++++++++---------- include/linux/fs.h | 18 +++++++++++++++--- 2 files changed, 54 insertions(+), 13 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 7fac262..17532ac 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1176,28 +1176,40 @@ static void time_out_leases(struct inode *inode) } } +static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker) +{ + if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) + return false; + return locks_conflict(breaker, lease); +} + /** * __break_lease - revoke all outstanding leases on file * @inode: the inode of the file to return - * @mode: the open mode (read or write) + * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR: + * break all leases + * @type: FL_LEASE: break leases and delegations; FL_DELEG: break + * only delegations * * break_lease (inlined for speed) has checked there already is at least * some kind of lock (maybe a lease) on this file. Leases are broken on * a call to open() or truncate(). This function can sleep unless you * specified %O_NONBLOCK to your open(). */ -int __break_lease(struct inode *inode, unsigned int mode) +int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) { int error = 0; struct file_lock *new_fl, *flock; struct file_lock *fl; unsigned long break_time; int i_have_this_lease = 0; + bool lease_conflict = false; int want_write = (mode & O_ACCMODE) != O_RDONLY; new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK); if (IS_ERR(new_fl)) return PTR_ERR(new_fl); + new_fl->fl_flags = type; lock_flocks(); @@ -1207,13 +1219,16 @@ int __break_lease(struct inode *inode, unsigned int mode) if ((flock == NULL) || !IS_LEASE(flock)) goto out; - if (!locks_conflict(flock, new_fl)) + for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { + if (leases_conflict(fl, new_fl)) { + lease_conflict = true; + if (fl->fl_owner == current->files) + i_have_this_lease = 1; + } + } + if (!lease_conflict) goto out; - for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) - if (fl->fl_owner == current->files) - i_have_this_lease = 1; - break_time = 0; if (lease_break_time > 0) { break_time = jiffies + lease_break_time * HZ; @@ -1222,6 +1237,8 @@ int __break_lease(struct inode *inode, unsigned int mode) } for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { + if (!leases_conflict(fl, new_fl)) + continue; if (want_write) { if (fl->fl_flags & FL_UNLOCK_PENDING) continue; @@ -1263,7 +1280,7 @@ restart: */ for (flock = inode->i_flock; flock && IS_LEASE(flock); flock = flock->fl_next) { - if (locks_conflict(new_fl, flock)) + if (leases_conflict(new_fl, flock)) goto restart; } error = 0; @@ -1343,9 +1360,20 @@ int generic_add_lease(struct file *filp, long arg, struct file_lock **flp) struct file_lock *fl, **before, **my_before = NULL, *lease; struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; + bool is_deleg = (*flp)->fl_flags & FL_DELEG; int error; lease = *flp; + /* + * In the delegation case we need mutual exclusion with + * a number of operations that take the i_mutex. We trylock + * because delegations are an optional optimization, and if + * there's some chance of a conflict--we'd rather not + * bother, maybe that's a sign this just isn't a good file to + * hand out a delegation on. + */ + if (is_deleg && !mutex_trylock(&inode->i_mutex)) + return -EAGAIN; error = -EAGAIN; if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) @@ -1397,9 +1425,10 @@ int generic_add_lease(struct file *filp, long arg, struct file_lock **flp) goto out; locks_insert_lock(before, lease); - return 0; - + error = 0; out: + if (is_deleg) + mutex_unlock(&inode->i_mutex); return error; } diff --git a/include/linux/fs.h b/include/linux/fs.h index eae4f10..a05ac23 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -938,7 +938,7 @@ extern int vfs_test_lock(struct file *, struct file_lock *); extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *); extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl); extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl); -extern int __break_lease(struct inode *inode, unsigned int flags); +extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type); extern void lease_get_mtime(struct inode *, struct timespec *time); extern int generic_setlease(struct file *, long, struct file_lock **); extern int vfs_setlease(struct file *, long, struct file_lock **); @@ -1051,7 +1051,7 @@ static inline int flock_lock_file_wait(struct file *filp, return -ENOLCK; } -static inline int __break_lease(struct inode *inode, unsigned int mode) +static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) { return 0; } @@ -1827,9 +1827,17 @@ static inline int locks_verify_truncate(struct inode *inode, static inline int break_lease(struct inode *inode, unsigned int mode) { if (inode->i_flock) - return __break_lease(inode, mode); + return __break_lease(inode, mode, FL_LEASE); return 0; } + +static inline int break_deleg(struct inode *inode, unsigned int mode) +{ + if (inode->i_flock) + return __break_lease(inode, mode, FL_DELEG); + return 0; +} + #else /* !CONFIG_FILE_LOCKING */ static inline int locks_mandatory_locked(struct inode *inode) { @@ -1869,6 +1877,10 @@ static inline int break_lease(struct inode *inode, unsigned int mode) return 0; } +static inline int break_deleg(struct inode *inode, unsigned int mode) +{ + return 0; +} #endif /* CONFIG_FILE_LOCKING */ /* fs/open.c */