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

[David Howells]

David Howells <dhowells at redhat.com> wrote:

> I think it would make sense to merge the two xdr_encode_YFSStoreStatus*()
> functions together.  See attached.

Sorry, that was on top of my fscache-rewrite-indexing branch.  Try the
attached instead.

David
---
From: Marc Dionne <marc.dionne at auristor.com>

afs: Set mtime from the client for yfs create operations

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.

[dhowells: Merge the two xdr_encode_YFSStoreStatus*() functions together]

Signed-off-by: Marc Dionne <marc.dionne at auristor.com>
Signed-off-by: David Howells <dhowells at redhat.com>
Link: http://lists.infradead.org/pipermail/linux-afs/2021-October/004395.html
---
 fs/afs/yfsclient.c |   32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/fs/afs/yfsclient.c b/fs/afs/yfsclient.c
index 2b35cba8ad62..6eeb78b1b979 100644
--- a/fs/afs/yfsclient.c
+++ b/fs/afs/yfsclient.c
@@ -83,25 +83,18 @@ 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)
-{
-	struct yfs_xdr_YFSStoreStatus *x = (void *)bp;
-
-	x->mask		= htonl(AFS_SET_MODE);
-	x->mode		= htonl(mode & S_IALLUGO);
-	x->mtime_client	= u64_to_xdr(0);
-	x->owner	= u64_to_xdr(0);
-	x->group	= u64_to_xdr(0);
-	return bp + xdr_size(x);
-}
-
-static __be32 *xdr_encode_YFSStoreStatus_mtime(__be32 *bp, const struct timespec64 *t)
+static __be32 *xdr_encode_YFSStoreStatus(__be32 *bp, mode_t *mode,
+					 const struct timespec64 *t)
 {
 	struct yfs_xdr_YFSStoreStatus *x = (void *)bp;
+	mode_t masked_mode = mode ? *mode & S_IALLUGO : 0;
 	s64 mtime = linux_to_yfs_time(t);
+	u32 mask = AFS_SET_MTIME;
 
-	x->mask		= htonl(AFS_SET_MTIME);
-	x->mode		= htonl(0);
+	mask |= mode ? AFS_SET_MODE : 0;
+
+	x->mask		= htonl(mask);
+	x->mode		= htonl(masked_mode);
 	x->mtime_client	= u64_to_xdr(mtime);
 	x->owner	= u64_to_xdr(0);
 	x->group	= u64_to_xdr(0);
@@ -576,7 +569,7 @@ 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(bp, &op->create.mode, &op->mtime);
 	bp = xdr_encode_u32(bp, yfs_LockNone); /* ViceLockType */
 	yfs_check_req(call, bp);
 
@@ -625,7 +618,7 @@ 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(bp, &op->create.mode, &op->mtime);
 	yfs_check_req(call, bp);
 
 	trace_afs_make_fs_call1(call, &dvp->fid, name);
@@ -946,6 +939,7 @@ void yfs_fs_symlink(struct afs_operation *op)
 	struct afs_vnode_param *dvp = &op->file[0];
 	struct afs_call *call;
 	size_t contents_sz;
+	mode_t mode = S_IRWXUGO;
 	__be32 *bp;
 
 	_enter("");
@@ -972,7 +966,7 @@ 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(bp, &mode, &op->mtime);
 	yfs_check_req(call, bp);
 
 	trace_afs_make_fs_call1(call, &dvp->fid, name);
@@ -1103,7 +1097,7 @@ void yfs_fs_store_data(struct afs_operation *op)
 	bp = xdr_encode_u32(bp, YFSSTOREDATA64);
 	bp = xdr_encode_u32(bp, 0); /* RPC flags */
 	bp = xdr_encode_YFSFid(bp, &vp->fid);
-	bp = xdr_encode_YFSStoreStatus_mtime(bp, &op->mtime);
+	bp = xdr_encode_YFSStoreStatus(bp, NULL, &op->mtime);
 	bp = xdr_encode_u64(bp, op->store.pos);
 	bp = xdr_encode_u64(bp, op->store.size);
 	bp = xdr_encode_u64(bp, op->store.i_size);