[PATCH 06/12] statx: NFS: Return enhanced file attributes
From: David Howells <dhowells@redhat.com>
Date: 2015-11-20 14:55:42
Also in:
linux-cifs, linux-fsdevel, linux-nfs, lkml
Subsystem:
filesystems (vfs and infrastructure), nfs, sunrpc, and lockd clients, the rest · Maintainers:
Alexander Viro, Christian Brauner, Trond Myklebust, Anna Schumaker, Linus Torvalds
Return enhanced file atrributes from the NFS filesystem. This includes the
following:
(1) The change attribute as st_version if NFSv4.
(2) STATX_INFO_AUTOMOUNT and STATX_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) STATX_INFO_REMOTE is set on files acquired over NFS.
(4) STATX_IOC_FLAGS is set and if the atime is unavailable on a file,
st_ioc_flags will have FL_NOATIME_FL set in it.
Furthermore, what nfs_getattr() does can be controlled as follows:
(1) If AT_NO_ATTR_SYNC is indicated then this will suppress the flushing
of outstanding writes and the rereading of the inode's attributes with
the server as detailed below.
(2) Otherwise:
(a) 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.
(b) The inode's attributes will be reread from the server:
(i) if AT_FORCE_ATTR_SYNC is indicated;
(ii) if atime is requested (and atime updating is not suppressed by
a mount flag); or
(iii) if the cached attributes have expired;
If the inode isn't synchronised, then the cached attributes will be used -
even if expired - without reference to the server.
Example output:
[root@andromeda ~]# ./samples/statx/test-statx /warthog/
statx(/warthog/) = 0
results=37ef
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 2 Links: 122
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2015-10-30 16:15:41.730925545+0000
Modify: 2015-10-07 10:33:19.896108112+0100
Change: 2015-10-07 10:33:19.896108112+0100
Data version: 5614e6df35698650h
Inode flags: 00000000 (-------- -------- -------- --------)
Information: 00000010 (-------- -------- -------- ---r----)
IO-blocksize: blksize=1048576
Note that the NFS4 protocol potentially provides a creation time that could
be passed through this interface and system, hidden and archive values that
could be passed as IOC flags. There is also a backup time that could be
added.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/nfs/inode.c | 45 ++++++++++++++++++++++++++++++++++++++-------
1 file changed, 38 insertions(+), 7 deletions(-)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 326d9e10d833..4d86663e37b2 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c@@ -645,12 +645,23 @@ static bool nfs_need_revalidate_inode(struct inode *inode) int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct inode *inode = d_inode(dentry); - int need_atime = NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATIME; + bool force_sync = stat->query_flags & AT_FORCE_ATTR_SYNC; + bool suppress_sync = stat->query_flags & AT_NO_ATTR_SYNC; + bool need_atime = NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATIME; int err = 0; trace_nfs_getattr_enter(inode); - /* 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 &= ~STATX_VERSION; + + /* Flush out writes to the server in order to update c/mtime or data + * version if the user wants them. + */ + if (S_ISREG(inode->i_mode) && !suppress_sync && + (force_sync || (stat->request_mask & + (STATX_MTIME | STATX_CTIME | STATX_VERSION))) + ) { mutex_lock(&inode->i_mutex); err = nfs_sync_inode(inode); mutex_unlock(&inode->i_mutex);
@@ -667,11 +678,16 @@ 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))) - need_atime = 0; + if ((mnt->mnt_flags & MNT_NOATIME) || + ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))) { + stat->ioc_flags |= FS_NOATIME_FL; + need_atime = false; + } else if (!(stat->request_mask & STATX_ATIME)) { + need_atime = false; + } - if (need_atime || nfs_need_revalidate_inode(inode)) { + if (!suppress_sync && + (force_sync || need_atime || nfs_need_revalidate_inode(inode))) { struct nfs_server *server = NFS_SERVER(inode); if (server->caps & NFS_CAP_READDIRPLUS)
@@ -684,6 +700,21 @@ int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) if (S_ISDIR(inode->i_mode)) stat->blksize = NFS_SERVER(inode)->dtsize; } + + generic_fillattr(inode, stat); + stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode)); + + if (stat->request_mask & STATX_VERSION) { + stat->version = inode->i_version; + stat->result_mask |= STATX_VERSION; + } + + if (IS_AUTOMOUNT(inode)) + stat->information |= STATX_INFO_FABRICATED; + + stat->information |= STATX_INFO_REMOTE; + stat->result_mask |= STATX_IOC_FLAGS; + out: trace_nfs_getattr_exit(inode, err); return err;