[PATCH] afs: Set mtime from the client for yfs create operations

[Marc Dionne]

For operations that create vnodes on the server such as CreateFile,
MakeDir or Symlink, the server will store its own current time as
the mtime if the client doesn't pass in a time in the accompanying
StoreStatus structure.

If the server and client clocks are not well synchronized, the client
may see timestamps in the future or inconsistent dependency checks
with "make" for files that are not modified after creation:

make[2]: Warning: File 'arch/x86/kernel/apic/modules.order' has
modification time 0.14 s in the future
make[2]: warning:  Clock skew detected.  Your build may be incomplete.

This is already handled correctly for non yfs operations; also
set the mtime for the corresponding yfs operations.

Signed-off-by: Marc Dionne <marc.dionne at auristor.com>
---
 fs/afs/yfsclient.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/afs/yfsclient.c b/fs/afs/yfsclient.c
index 2b35cba8ad62..82b7065e588b 100644
--- a/fs/afs/yfsclient.c
+++ b/fs/afs/yfsclient.c
@@ -83,13 +83,15 @@ static s64 linux_to_yfs_time(const struct timespec64 *t)
 	return (u64)t->tv_sec * 10000000 + t->tv_nsec/100;
 }
 
-static __be32 *xdr_encode_YFSStoreStatus_mode(__be32 *bp, mode_t mode)
+static __be32 *xdr_encode_YFSStoreStatus_mode_time(__be32 *bp, mode_t mode,
+						   const struct timespec64 *t)
 {
 	struct yfs_xdr_YFSStoreStatus *x = (void *)bp;
+	s64 mtime = linux_to_yfs_time(t);
 
-	x->mask		= htonl(AFS_SET_MODE);
+	x->mask		= htonl(AFS_SET_MODE | AFS_SET_MTIME);
 	x->mode		= htonl(mode & S_IALLUGO);
-	x->mtime_client	= u64_to_xdr(0);
+	x->mtime_client	= u64_to_xdr(mtime);
 	x->owner	= u64_to_xdr(0);
 	x->group	= u64_to_xdr(0);
 	return bp + xdr_size(x);
@@ -576,7 +578,7 @@ void yfs_fs_create_file(struct afs_operation *op)
 	bp = xdr_encode_u32(bp, 0); /* RPC flags */
 	bp = xdr_encode_YFSFid(bp, &dvp->fid);
 	bp = xdr_encode_name(bp, name);
-	bp = xdr_encode_YFSStoreStatus_mode(bp, op->create.mode);
+	bp = xdr_encode_YFSStoreStatus_mode_time(bp, op->create.mode, &op->mtime);
 	bp = xdr_encode_u32(bp, yfs_LockNone); /* ViceLockType */
 	yfs_check_req(call, bp);
 
@@ -625,7 +627,7 @@ void yfs_fs_make_dir(struct afs_operation *op)
 	bp = xdr_encode_u32(bp, 0); /* RPC flags */
 	bp = xdr_encode_YFSFid(bp, &dvp->fid);
 	bp = xdr_encode_name(bp, name);
-	bp = xdr_encode_YFSStoreStatus_mode(bp, op->create.mode);
+	bp = xdr_encode_YFSStoreStatus_mode_time(bp, op->create.mode, &op->mtime);
 	yfs_check_req(call, bp);
 
 	trace_afs_make_fs_call1(call, &dvp->fid, name);
@@ -972,7 +974,7 @@ void yfs_fs_symlink(struct afs_operation *op)
 	bp = xdr_encode_YFSFid(bp, &dvp->fid);
 	bp = xdr_encode_name(bp, name);
 	bp = xdr_encode_string(bp, op->create.symlink, contents_sz);
-	bp = xdr_encode_YFSStoreStatus_mode(bp, S_IRWXUGO);
+	bp = xdr_encode_YFSStoreStatus_mode_time(bp, S_IRWXUGO, &op->mtime);
 	yfs_check_req(call, bp);
 
 	trace_afs_make_fs_call1(call, &dvp->fid, name);
-- 
2.33.0