Patch "nfsd: Record NFSv4 pre/post-op attributes as non-atomic" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    nfsd: Record NFSv4 pre/post-op attributes as non-atomic

to the 5.10-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-record-nfsv4-pre-post-op-attributes-as-non-atom.patch
and it can be found in the queue-5.10 subdirectory.

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



commit a89ced1800f4a3d8f2111666a4d0d7605e264333
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date:   Mon Nov 30 23:14:27 2020 -0500

    nfsd: Record NFSv4 pre/post-op attributes as non-atomic
    
    [ Upstream commit 716a8bc7f706eeef80ab42c99d9f210eda845c81 ]
    
    For the case of NFSv4, specify to the client that the pre/post-op
    attributes were not recorded atomically with the main operation.
    
    Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfs/export.c b/fs/nfs/export.c
index 48b879cfe6e3b..7412bb164fa77 100644
--- a/fs/nfs/export.c
+++ b/fs/nfs/export.c
@@ -172,5 +172,6 @@ const struct export_operations nfs_export_ops = {
 	.fh_to_dentry = nfs_fh_to_dentry,
 	.get_parent = nfs_get_parent,
 	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|
-		EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS,
+		EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS|
+		EXPORT_OP_NOATOMIC_ATTR,
 };
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index e80a7525561d0..66f2ef67792a7 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -301,6 +301,10 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 	fhp->fh_export = exp;
 
 	switch (rqstp->rq_vers) {
+	case 4:
+		if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOATOMIC_ATTR)
+			fhp->fh_no_atomic_attr = true;
+		break;
 	case 3:
 		if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOWCC)
 			fhp->fh_no_wcc = true;
diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
index 347d10aa62655..cb20c2cd34695 100644
--- a/fs/nfsd/nfsfh.h
+++ b/fs/nfsd/nfsfh.h
@@ -36,6 +36,11 @@ typedef struct svc_fh {
 	bool			fh_locked;	/* inode locked by us */
 	bool			fh_want_write;	/* remount protection taken */
 	bool			fh_no_wcc;	/* no wcc data needed */
+	bool			fh_no_atomic_attr;
+						/*
+						 * wcc data is not atomic with
+						 * operation
+						 */
 	int			fh_flags;	/* FH flags */
 #ifdef CONFIG_NFSD_V3
 	bool			fh_post_saved;	/* post-op attrs saved */
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index b4556e86e97c3..a60ff5ce1a375 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -748,7 +748,7 @@ static inline void
 set_change_info(struct nfsd4_change_info *cinfo, struct svc_fh *fhp)
 {
 	BUG_ON(!fhp->fh_pre_saved);
-	cinfo->atomic = (u32)fhp->fh_post_saved;
+	cinfo->atomic = (u32)(fhp->fh_post_saved && !fhp->fh_no_atomic_attr);
 
 	cinfo->before_change = fhp->fh_pre_change;
 	cinfo->after_change = fhp->fh_post_change;
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index d93e8a6737bb0..9f4d4bcbf251d 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -217,6 +217,9 @@ struct export_operations {
 #define	EXPORT_OP_NOSUBTREECHK		(0x2) /* no subtree checking */
 #define	EXPORT_OP_CLOSE_BEFORE_UNLINK	(0x4) /* close files before unlink */
 #define EXPORT_OP_REMOTE_FS		(0x8) /* Filesystem is remote */
+#define EXPORT_OP_NOATOMIC_ATTR		(0x10) /* Filesystem cannot supply
+						  atomic attribute updates
+						*/
 	unsigned long	flags;
 };