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Message-ID: <1334846149.21419.22.camel@lade.trondhjem.org>
Date: Thu, 19 Apr 2012 14:35:50 +0000
From: "Myklebust, Trond" <Trond.Myklebust@...app.com>
To: David Howells <dhowells@...hat.com>
CC: "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
"linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
"linux-cifs@...r.kernel.org" <linux-cifs@...r.kernel.org>,
"samba-technical@...ts.samba.org" <samba-technical@...ts.samba.org>,
"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
"wine-devel@...ehq.org" <wine-devel@...ehq.org>,
"kfm-devel@....org" <kfm-devel@....org>,
"nautilus-list@...me.org" <nautilus-list@...me.org>,
"linux-api@...r.kernel.org" <linux-api@...r.kernel.org>,
"libc-alpha@...rceware.org" <libc-alpha@...rceware.org>
Subject: Re: [PATCH 4/6] xstat: NFS: Return extended attributes
On Thu, 2012-04-19 at 15:06 +0100, David Howells wrote:
> Return extended attributes from the NFS filesystem. This includes the
> following:
>
> (1) The change attribute as st_data_version if NFSv4.
>
> (2) XSTAT_INFO_AUTOMOUNT and XSTAT_INFO_FABRICATED are set on referral or
> submount directories that are automounted upon. NFS shows one directory
> with a different FSID, but the local filesystem has two: the mountpoint
> directory and the root of the filesystem mounted upon it.
>
> (3) XSTAT_INFO_REMOTE is set on files acquired over NFS.
>
> Furthermore, what nfs_getattr() does can be controlled as follows:
>
> (1) If AT_FORCE_ATTR_SYNC is indicated, or mtime, ctime or data_version (NFSv4
> only) are requested then the outstanding writes will be written to the
> server first.
>
> (2) The inode's attributes may be synchronised with the server:
>
> (a) If AT_FORCE_ATTR_SYNC is indicated or if atime is requested (and atime
> updating is not suppressed by a mount flag) then the attributes will
> be reread unconditionally.
>
> (b) If the data version or any of basic stats are requested then the
> attributes will be reread if the cached attributes have expired.
>
> (c) Otherwise the cached attributes will be used - even if expired -
> without reference to the server.
Hmm... As far as I can see you are still doing an nfs_revalidate_inode()
in the non-forced case. That will cause expired attributes to be
retrieved from the server.
> Signed-off-by: David Howells <dhowells@...hat.com>
> ---
>
> fs/nfs/inode.c | 49 +++++++++++++++++++++++++++++++++++++------------
> fs/nfs/super.c | 1 +
> 2 files changed, 38 insertions(+), 12 deletions(-)
>
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index e8bbfa5..460fcf3 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -509,11 +509,18 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
> int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> {
> struct inode *inode = dentry->d_inode;
> + unsigned force = stat->query_flags & AT_FORCE_ATTR_SYNC;
> int need_atime = NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATIME;
> int err;
>
> - /* Flush out writes to the server in order to update c/mtime. */
> - if (S_ISREG(inode->i_mode)) {
> + if (NFS_SERVER(inode)->nfs_client->rpc_ops->version < 4)
> + stat->request_mask &= ~XSTAT_VERSION;
> +
> + /* Flush out writes to the server in order to update c/mtime
> + * or data version if the user wants them */
> + if ((force || (stat->request_mask &
> + (XSTAT_MTIME | XSTAT_CTIME | XSTAT_VERSION))) &&
> + S_ISREG(inode->i_mode)) {
> err = filemap_write_and_wait(inode->i_mapping);
We can get rid of the filemap_write_and_wait() if the caller allows us
to approximate m/ctime values. That would give a major speed-up for most
stat() workloads.
> if (err)
> goto out;
> @@ -528,18 +535,36 @@ int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> * - NFS never sets MS_NOATIME or MS_NODIRATIME so there is
> * no point in checking those.
> */
> - if ((mnt->mnt_flags & MNT_NOATIME) ||
> - ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
> + if (mnt->mnt_flags & MNT_NOATIME ||
> + (mnt->mnt_flags & MNT_NODIRATIME && S_ISDIR(inode->i_mode))) {
> + stat->ioc_flags |= FS_NOATIME_FL;
> + need_atime = 0;
> + } else if (!(stat->request_mask & XSTAT_ATIME)) {
> need_atime = 0;
> + }
>
> - if (need_atime)
> - err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
> - else
> - err = nfs_revalidate_inode(NFS_SERVER(inode), inode);
> - if (!err) {
> - generic_fillattr(inode, stat);
> - stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
> + if (force || stat->request_mask & (XSTAT_BASIC_STATS | XSTAT_VERSION)) {
> + if (force || need_atime)
> + err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
> + else
> + err = nfs_revalidate_inode(NFS_SERVER(inode), inode);
> + if (err)
> + goto out;
> }
> +
> + generic_fillattr(inode, stat);
> + stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
> +
> + if (stat->request_mask & XSTAT_VERSION) {
> + stat->version = inode->i_version;
> + stat->result_mask |= XSTAT_VERSION;
> + }
> +
> + if (IS_AUTOMOUNT(inode))
> + stat->information |= XSTAT_INFO_FABRICATED;
> +
> + stat->information |= XSTAT_INFO_REMOTE;
> +
> out:
> return err;
> }
> @@ -852,7 +877,7 @@ int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
> static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
> {
> struct nfs_inode *nfsi = NFS_I(inode);
> -
> +
> if (mapping->nrpages != 0) {
> int ret = invalidate_inode_pages2(mapping);
> if (ret < 0)
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 37412f7..faa652c 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -2222,6 +2222,7 @@ static int nfs_set_super(struct super_block *s, void *data)
> ret = set_anon_super(s, server);
> if (ret == 0)
> server->s_dev = s->s_dev;
> + memcpy(&s->s_volume_id, &server->fsid, sizeof(s->s_volume_id));
> return ret;
> }
>
>
> --
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--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@...app.com
www.netapp.com
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