Patch "nfsd: fix initial getattr on write delegation" has been added to the 6.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    nfsd: fix initial getattr on write delegation

to the 6.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfsd-fix-initial-getattr-on-write-delegation.patch
and it can be found in the queue-6.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit aca38c768e9cfd838fbd3a43a7d8c1e2082d6890
Author: Jeff Layton <jlayton@xxxxxxxxxx>
Date:   Mon Sep 9 10:40:53 2024 -0400

    nfsd: fix initial getattr on write delegation
    
    [ Upstream commit bf92e5008b17f935a6de8b708551e02c2294121c ]
    
    At this point in compound processing, currentfh refers to the parent of
    the file, not the file itself. Get the correct dentry from the delegation
    stateid instead.
    
    Fixes: c5967721e106 ("NFSD: handle GETATTR conflict with write delegation")
    Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 29c11714ac3db..fe06779ea527a 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5912,6 +5912,28 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
 	}
 }
 
+static bool
+nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
+		     struct kstat *stat)
+{
+	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);
+	struct path path;
+	int rc;
+
+	if (!nf)
+		return false;
+
+	path.mnt = currentfh->fh_export->ex_path.mnt;
+	path.dentry = file_dentry(nf->nf_file);
+
+	rc = vfs_getattr(&path, stat,
+			 (STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
+			 AT_STATX_SYNC_AS_STAT);
+
+	nfsd_file_put(nf);
+	return rc == 0;
+}
+
 /*
  * The Linux NFS server does not offer write delegations to NFSv4.0
  * clients in order to avoid conflicts between write delegations and
@@ -5947,7 +5969,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	int cb_up;
 	int status = 0;
 	struct kstat stat;
-	struct path path;
 
 	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
 	open->op_recall = false;
@@ -5983,20 +6004,16 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
 
 	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
-		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
-		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
-		path.mnt = currentfh->fh_export->ex_path.mnt;
-		path.dentry = currentfh->fh_dentry;
-		if (vfs_getattr(&path, &stat,
-				(STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
-				AT_STATX_SYNC_AS_STAT)) {
+		if (!nfs4_delegation_stat(dp, currentfh, &stat)) {
 			nfs4_put_stid(&dp->dl_stid);
 			destroy_delegation(dp);
 			goto out_no_deleg;
 		}
+		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
 		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
 		dp->dl_cb_fattr.ncf_initial_cinfo =
 			nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
+		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
 	} else {
 		open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
 		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);