Return-Path: Received: from mail-io0-f196.google.com ([209.85.223.196]:35707 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755789AbcGFWaj (ORCPT ); Wed, 6 Jul 2016 18:30:39 -0400 Received: by mail-io0-f196.google.com with SMTP id k78so901998ioi.2 for ; Wed, 06 Jul 2016 15:30:38 -0700 (PDT) From: Trond Myklebust To: linux-nfs@vger.kernel.org Subject: [PATCH v4 03/28] NFS: Cache aggressively when file is open for writing Date: Wed, 6 Jul 2016 18:29:40 -0400 Message-Id: <1467844205-76852-4-git-send-email-trond.myklebust@primarydata.com> In-Reply-To: <1467844205-76852-3-git-send-email-trond.myklebust@primarydata.com> References: <1467844205-76852-1-git-send-email-trond.myklebust@primarydata.com> <1467844205-76852-2-git-send-email-trond.myklebust@primarydata.com> <1467844205-76852-3-git-send-email-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Unless the user is using file locking, we must assume close-to-open cache consistency when the file is open for writing. Adjust the caching algorithm so that it does not clear the cache on out-of-order writes and/or attribute revalidations. Signed-off-by: Trond Myklebust --- fs/nfs/file.c | 13 ++---------- fs/nfs/inode.c | 62 +++++++++++++++++++++++++++++++++++++++++----------------- 2 files changed, 46 insertions(+), 29 deletions(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 717a8d6af52d..2d39d9f9da7d 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -780,11 +780,6 @@ do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) } static int -is_time_granular(struct timespec *ts) { - return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000)); -} - -static int do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) { struct inode *inode = filp->f_mapping->host; @@ -817,12 +812,8 @@ do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) * This makes locking act as a cache coherency point. */ nfs_sync_mapping(filp->f_mapping); - if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) { - if (is_time_granular(&NFS_SERVER(inode)->time_delta)) - __nfs_revalidate_inode(NFS_SERVER(inode), inode); - else - nfs_zap_caches(inode); - } + if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) + nfs_zap_mapping(inode, filp->f_mapping); out: return status; } diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 60051e62d3f1..4e65a5a8a01b 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -878,7 +878,10 @@ void nfs_inode_attach_open_context(struct nfs_open_context *ctx) struct nfs_inode *nfsi = NFS_I(inode); spin_lock(&inode->i_lock); - list_add(&ctx->list, &nfsi->open_files); + if (ctx->mode & FMODE_WRITE) + list_add(&ctx->list, &nfsi->open_files); + else + list_add_tail(&ctx->list, &nfsi->open_files); spin_unlock(&inode->i_lock); } EXPORT_SYMBOL_GPL(nfs_inode_attach_open_context); @@ -1215,6 +1218,25 @@ int nfs_revalidate_mapping_protected(struct inode *inode, struct address_space * return __nfs_revalidate_mapping(inode, mapping, true); } +static bool nfs_file_has_writers(struct nfs_inode *nfsi) +{ + struct inode *inode = &nfsi->vfs_inode; + + assert_spin_locked(&inode->i_lock); + + if (!S_ISREG(inode->i_mode)) + return false; + if (list_empty(&nfsi->open_files)) + return false; + /* Note: This relies on nfsi->open_files being ordered with writers + * being placed at the head of the list. + * See nfs_inode_attach_open_context() + */ + return (list_first_entry(&nfsi->open_files, + struct nfs_open_context, + list)->mode & FMODE_WRITE) == FMODE_WRITE; +} + static unsigned long nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr) { struct nfs_inode *nfsi = NFS_I(inode); @@ -1279,22 +1301,24 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat if ((fattr->valid & NFS_ATTR_FATTR_TYPE) && (inode->i_mode & S_IFMT) != (fattr->mode & S_IFMT)) return -EIO; - if ((fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 && - inode->i_version != fattr->change_attr) - invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE; + if (!nfs_file_has_writers(nfsi)) { + /* Verify a few of the more important attributes */ + if ((fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 && inode->i_version != fattr->change_attr) + invalid |= NFS_INO_INVALID_ATTR | NFS_INO_REVAL_PAGECACHE; - /* Verify a few of the more important attributes */ - if ((fattr->valid & NFS_ATTR_FATTR_MTIME) && !timespec_equal(&inode->i_mtime, &fattr->mtime)) - invalid |= NFS_INO_INVALID_ATTR; + if ((fattr->valid & NFS_ATTR_FATTR_MTIME) && !timespec_equal(&inode->i_mtime, &fattr->mtime)) + invalid |= NFS_INO_INVALID_ATTR; - if (fattr->valid & NFS_ATTR_FATTR_SIZE) { - cur_size = i_size_read(inode); - new_isize = nfs_size_to_loff_t(fattr->size); - if (cur_size != new_isize) - invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE; + if ((fattr->valid & NFS_ATTR_FATTR_CTIME) && !timespec_equal(&inode->i_ctime, &fattr->ctime)) + invalid |= NFS_INO_INVALID_ATTR; + + if (fattr->valid & NFS_ATTR_FATTR_SIZE) { + cur_size = i_size_read(inode); + new_isize = nfs_size_to_loff_t(fattr->size); + if (cur_size != new_isize) + invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE; + } } - if (nfsi->nrequests != 0) - invalid &= ~NFS_INO_REVAL_PAGECACHE; /* Have any file permissions changed? */ if ((fattr->valid & NFS_ATTR_FATTR_MODE) && (inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO)) @@ -1526,7 +1550,7 @@ EXPORT_SYMBOL_GPL(nfs_refresh_inode); static int nfs_post_op_update_inode_locked(struct inode *inode, struct nfs_fattr *fattr) { - unsigned long invalid = NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE; + unsigned long invalid = NFS_INO_INVALID_ATTR; /* * Don't revalidate the pagecache if we hold a delegation, but do @@ -1675,6 +1699,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) unsigned long invalid = 0; unsigned long now = jiffies; unsigned long save_cache_validity; + bool have_writers = nfs_file_has_writers(nfsi); bool cache_revalidated = true; dfprintk(VFS, "NFS: %s(%s/%lu fh_crc=0x%08x ct=%d info=0x%x)\n", @@ -1730,7 +1755,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) dprintk("NFS: change_attr change on server for file %s/%ld\n", inode->i_sb->s_id, inode->i_ino); /* Could it be a race with writeback? */ - if (nfsi->nrequests == 0) { + if (!have_writers) { invalid |= NFS_INO_INVALID_ATTR | NFS_INO_INVALID_DATA | NFS_INO_INVALID_ACCESS @@ -1770,9 +1795,10 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) if (new_isize != cur_isize) { /* Do we perhaps have any outstanding writes, or has * the file grown beyond our last write? */ - if ((nfsi->nrequests == 0) || new_isize > cur_isize) { + if (nfsi->nrequests == 0 || new_isize > cur_isize) { i_size_write(inode, new_isize); - invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA; + if (!have_writers) + invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA; } dprintk("NFS: isize change on server for file %s/%ld " "(%Ld to %Ld)\n", -- 2.7.4