[4/4] 9pfs: Introduce futimens file op

Commit Message

Greg Kurz March 10, 2025, 5:11 p.m. UTC

Add an futimens operation to the fs driver and use if when a fid has
a valid file descriptor. This is required to support more cases where
the client wants to do an action on an unlinked file which it still
has an open file decriptor for.

Only 9P2000.L was considered.

Signed-off-by: Greg Kurz <[e-mail]>
---
 fsdev/file-op-9p.h |  2 ++
 hw/9pfs/9p-local.c |  9 +++++++++
 hw/9pfs/9p-synth.c |  8 ++++++++
 hw/9pfs/9p-util.h  |  1 +
 hw/9pfs/9p.c       |  6 +++++-
 hw/9pfs/cofs.c     | 19 +++++++++++++++++++
 hw/9pfs/coth.h     |  2 ++
 7 files changed, 46 insertions(+), 1 deletion(-)

Patch

diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
index 40a40f7d8af8..ee65f4ffad2f 100644
--- a/fsdev/file-op-9p.h
+++ b/fsdev/file-op-9p.h
@@ -167,6 +167,8 @@  struct FileOperations {
     bool (*has_valid_handle)(int fid_type, V9fsFidOpenState *fs);
     int (*ftruncate)(FsContext *ctx, int fid_type, V9fsFidOpenState *fs,
                      off_t size);
+    int (*futimens)(FsContext *ctx, int fid_type, V9fsFidOpenState *fs,
+                    const struct timespec *times);
 };
 
 #endif
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index fa763b0662f5..f8b932802c17 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -1104,6 +1104,14 @@  out:
     return ret;
 }
 
+static int local_futimens(FsContext *s, int fid_type, V9fsFidOpenState *fs,
+                          const struct timespec *times)
+{
+    int fd = local_fid_fd(fid_type, fs);
+
+    return qemu_futimens(fd, times);
+}
+
 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
                                  int flags)
 {
@@ -1628,4 +1636,5 @@  FileOperations local_ops = {
     .unlinkat = local_unlinkat,
     .has_valid_handle = local_has_valid_handle,
     .ftruncate = local_ftruncate,
+    .futimens = local_futimens,
 };
diff --git a/hw/9pfs/9p-synth.c b/hw/9pfs/9p-synth.c
index 7f0e13f0ddd8..3bf4bb17e767 100644
--- a/hw/9pfs/9p-synth.c
+++ b/hw/9pfs/9p-synth.c
@@ -424,6 +424,13 @@  static int synth_utimensat(FsContext *fs_ctx, V9fsPath *path,
     return 0;
 }
 
+static int synth_futimens(FsContext *fs_ctx, int fid_type, V9fsFidOpenState *fs,
+                          const struct timespec *buf)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
 static int synth_remove(FsContext *ctx, const char *path)
 {
     errno = EPERM;
@@ -664,4 +671,5 @@  FileOperations synth_ops = {
     .unlinkat     = synth_unlinkat,
     .has_valid_handle = synth_has_valid_handle,
     .ftruncate    = synth_ftruncate,
+    .futimens     = synth_futimens,
 };
diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index 7bc4ec8e85cc..a1924fe3f05a 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -103,6 +103,7 @@  static inline int errno_to_dotl(int err) {
 #define qemu_renameat   renameat
 #define qemu_utimensat  utimensat
 #define qemu_unlinkat   unlinkat
+#define qemu_futimens   futimens
 
 static inline void close_preserve_errno(int fd)
 {
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 35b2ed900a01..8024cc06a090 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1708,7 +1708,11 @@  static void coroutine_fn v9fs_setattr(void *opaque)
         } else {
             times[1].tv_nsec = UTIME_OMIT;
         }
-        err = v9fs_co_utimensat(pdu, &fidp->path, times);
+        if (fid_has_valid_handle(pdu->s, fidp)) {
+            err = v9fs_co_futimens(pdu, fidp, times);
+        } else {
+            err = v9fs_co_utimensat(pdu, &fidp->path, times);
+        }
         if (err < 0) {
             goto out;
         }
diff --git a/hw/9pfs/cofs.c b/hw/9pfs/cofs.c
index 893466fb1a44..12fa8c9fe9cd 100644
--- a/hw/9pfs/cofs.c
+++ b/hw/9pfs/cofs.c
@@ -139,6 +139,25 @@  int coroutine_fn v9fs_co_utimensat(V9fsPDU *pdu, V9fsPath *path,
     return err;
 }
 
+int coroutine_fn v9fs_co_futimens(V9fsPDU *pdu, V9fsFidState *fidp,
+                                  struct timespec times[2])
+{
+    int err;
+    V9fsState *s = pdu->s;
+
+    if (v9fs_request_cancelled(pdu)) {
+        return -EINTR;
+    }
+    v9fs_co_run_in_worker(
+        {
+            err = s->ops->futimens(&s->ctx, fidp->fid_type, &fidp->fs, times);
+            if (err < 0) {
+                err = -errno;
+            }
+        });
+    return err;
+}
+
 int coroutine_fn v9fs_co_chown(V9fsPDU *pdu, V9fsPath *path, uid_t uid,
                                gid_t gid)
 {
diff --git a/hw/9pfs/coth.h b/hw/9pfs/coth.h
index 0b8ee4c56495..9920f98129e9 100644
--- a/hw/9pfs/coth.h
+++ b/hw/9pfs/coth.h
@@ -111,5 +111,7 @@  int coroutine_fn v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t,
                                 V9fsStatDotl *v9stat);
 int coroutine_fn v9fs_co_ftruncate(V9fsPDU *pdu, V9fsFidState *fidp,
                                    off_t size);
+int coroutine_fn v9fs_co_futimens(V9fsPDU *pdu, V9fsFidState *fidp,
+                                  struct timespec times[2]);
 
 #endif