Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-ie0-f173.google.com ([209.85.223.173]:50262 "EHLO mail-ie0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894AbaLXHOR (ORCPT ); Wed, 24 Dec 2014 02:14:17 -0500 Received: by mail-ie0-f173.google.com with SMTP id y20so7218868ier.18 for ; Tue, 23 Dec 2014 23:14:16 -0800 (PST) From: Tom Haynes To: Trond Myklebust Cc: Linux NFS Mailing List Subject: [PATCH v2 45/49] nfs/flexfiles: send layoutreturn before freeing lseg Date: Tue, 23 Dec 2014 23:13:24 -0800 Message-Id: <1419405208-25975-46-git-send-email-loghyr@primarydata.com> In-Reply-To: <1419405208-25975-1-git-send-email-loghyr@primarydata.com> References: <1419405208-25975-1-git-send-email-loghyr@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: From: Peng Tao Otherwise we'll lose error tracking information when encoding layoutreturn. pnfs_put_lseg may be called from rpc callbacks. So we should not call pnfs_send_layoutreturn directly because it can deadlock in the rpc layer. Signed-off-by: Peng Tao Signed-off-by: Tom Haynes --- fs/nfs/pnfs.c | 76 ++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 55 insertions(+), 21 deletions(-) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index e80014a..9e7092f 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -347,8 +347,7 @@ pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo, /* Return true if layoutreturn is needed */ static bool pnfs_layout_need_return(struct pnfs_layout_hdr *lo, - struct pnfs_layout_segment *lseg, - nfs4_stateid *stateid, enum pnfs_iomode *iomode) + struct pnfs_layout_segment *lseg) { struct pnfs_layout_segment *s; @@ -356,17 +355,55 @@ pnfs_layout_need_return(struct pnfs_layout_hdr *lo, return false; list_for_each_entry(s, &lo->plh_segs, pls_list) - if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags)) + if (s != lseg && test_bit(NFS_LSEG_LAYOUTRETURN, &s->pls_flags)) return false; - *stateid = lo->plh_stateid; - *iomode = lo->plh_return_iomode; - /* decreased in pnfs_send_layoutreturn() */ - lo->plh_block_lgets++; - lo->plh_return_iomode = 0; return true; } +static void pnfs_layoutreturn_free_lseg(struct work_struct *work) +{ + struct pnfs_layout_segment *lseg; + struct pnfs_layout_hdr *lo; + struct inode *inode; + + lseg = container_of(work, struct pnfs_layout_segment, pls_work); + WARN_ON(atomic_read(&lseg->pls_refcount)); + lo = lseg->pls_layout; + inode = lo->plh_inode; + + spin_lock(&inode->i_lock); + if (pnfs_layout_need_return(lo, lseg)) { + nfs4_stateid stateid; + enum pnfs_iomode iomode; + + stateid = lo->plh_stateid; + iomode = lo->plh_return_iomode; + /* decreased in pnfs_send_layoutreturn() */ + lo->plh_block_lgets++; + lo->plh_return_iomode = 0; + spin_unlock(&inode->i_lock); + + pnfs_send_layoutreturn(lo, stateid, iomode, 0, + NFS4_MAX_UINT64, true); + spin_lock(&inode->i_lock); + } else + /* match pnfs_get_layout_hdr #2 in pnfs_put_lseg */ + pnfs_put_layout_hdr(lo); + pnfs_layout_remove_lseg(lo, lseg); + spin_unlock(&inode->i_lock); + pnfs_free_lseg(lseg); + /* match pnfs_get_layout_hdr #1 in pnfs_put_lseg */ + pnfs_put_layout_hdr(lo); +} + +static void +pnfs_layoutreturn_free_lseg_async(struct pnfs_layout_segment *lseg) +{ + INIT_WORK(&lseg->pls_work, pnfs_layoutreturn_free_lseg); + queue_work(nfsiod_workqueue, &lseg->pls_work); +} + void pnfs_put_lseg(struct pnfs_layout_segment *lseg) { @@ -382,21 +419,18 @@ pnfs_put_lseg(struct pnfs_layout_segment *lseg) lo = lseg->pls_layout; inode = lo->plh_inode; if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) { - bool need_return; - nfs4_stateid stateid; - enum pnfs_iomode iomode; - pnfs_get_layout_hdr(lo); - pnfs_layout_remove_lseg(lo, lseg); - need_return = pnfs_layout_need_return(lo, lseg, - &stateid, &iomode); - spin_unlock(&inode->i_lock); - pnfs_free_lseg(lseg); - if (need_return) - pnfs_send_layoutreturn(lo, stateid, iomode, 0, - NFS4_MAX_UINT64, true); - else + if (pnfs_layout_need_return(lo, lseg)) { + spin_unlock(&inode->i_lock); + /* hdr reference dropped in nfs4_layoutreturn_release */ + pnfs_get_layout_hdr(lo); + pnfs_layoutreturn_free_lseg_async(lseg); + } else { + pnfs_layout_remove_lseg(lo, lseg); + spin_unlock(&inode->i_lock); + pnfs_free_lseg(lseg); pnfs_put_layout_hdr(lo); + } } } EXPORT_SYMBOL_GPL(pnfs_put_lseg); -- 1.9.3