[PATCH 3/4] statx: NFS: Return enhanced file attributes [ver #3]
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STALE3595d
From: David Howells <dhowells@redhat.com>
Date: 2016-11-23 00:59:04
Also in:
linux-fsdevel, 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) STATX_ATTR_AUTOMOUNT is set on referral or submount directories that
are automounted upon. NFS shows one directory with a different FSID,
but the local VFS has two: the mountpoint directory (fabricated) and
the root of the filesystem mounted upon it.
Furthermore, what nfs_getattr() does can be controlled as follows:
(1) If AT_STATX_DONT_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_STATX_FORCE_SYNC is indicated, or mtime or ctime 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_STATX_FORCE_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=17ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 2 Links: 21
Access: (0555/dr-xr-xr-x) Uid: 0 Gid: 0
Access: 2016-11-14 11:49:14.582749262+0000
Modify: 2016-09-08 20:39:46.785788707+0100
Change: 2016-09-08 20:39:46.785788707+0100
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 attributes. There is also a backup time that could be
exposed.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/nfs/inode.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index bf4ec5ecc97e..3002350d4a84 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c@@ -656,12 +656,20 @@ 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; + unsigned int sync_type = stat->query_flags & AT_STATX_SYNC_TYPE; + 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)) { + + /* Flush out writes to the server in order to update c/mtime if the + * user wants them. + */ + if (sync_type != AT_STATX_DONT_SYNC && + S_ISREG(inode->i_mode) && + (sync_type == AT_STATX_FORCE_SYNC || + (stat->request_mask & (STATX_MTIME | STATX_CTIME))) + ) { err = filemap_write_and_wait(inode->i_mapping); if (err) goto out;
@@ -676,11 +684,15 @@ 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 (need_atime || nfs_need_revalidate_inode(inode)) { + if (!(stat->request_mask & STATX_ATIME) || + (mnt->mnt_flags & MNT_NOATIME) || + ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))) + need_atime = false; + + if (sync_type != AT_STATX_DONT_SYNC && + (sync_type == AT_STATX_FORCE_SYNC || + need_atime || + nfs_need_revalidate_inode(inode))) { struct nfs_server *server = NFS_SERVER(inode); if (server->caps & NFS_CAP_READDIRPLUS)
@@ -693,6 +705,10 @@ 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)); + out: trace_nfs_getattr_exit(inode, err); return err;