Return enhanced file atrributes from the NFS filesystem. This includes the
following:
(1) The change attribute as stx_version if NFSv4.
(2) STATX_ATTR_AUTOMOUNT and STATX_ATTR_FABRICATED are 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.
(3) STATX_ATTR_REMOTE is set on files acquired over NFS.
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, 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_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
Data version: 57d1be822ed62f23h
Attributes: 0000000000002000 (-------- -------- -------- -------- -------- -------- --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 attributes. There is also a backup time that could be
exposed.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---
fs/nfs/inode.c | 41 ++++++++++++++++++++++++++++++++++-------
1 file changed, 34 insertions(+), 7 deletions(-)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index bf4ec5ecc97e..73c4502d4abb 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -656,12 +656,23 @@ 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_STATX_FORCE_SYNC;
+ bool suppress_sync = stat->query_flags & AT_STATX_DONT_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)))
+ ) {
err = filemap_write_and_wait(inode->i_mapping);
if (err)
goto out;
@@ -676,11 +687,13 @@ 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 (!(stat->request_mask & STATX_ATIME) ||
+ (mnt->mnt_flags & MNT_NOATIME) ||
+ ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
+ 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)
@@ -693,6 +706,20 @@ 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->attributes |= STATX_ATTR_FABRICATED;
+
+ stat->attributes |= STATX_ATTR_REMOTE;
+
out:
trace_nfs_getattr_exit(inode, err);
return err;
--
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