[Qemu-devel] [PATCH -V3 4/8] hw/9pfs: Implement syncfs

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

SYNOPSIS
    size[4] Tsyncfs tag[2] fid[4]

    size[4] Rsyncfs tag[2]

DESCRIPTION
    The Tsyncfs transaction transfers ("flushes") all modified data of
    file system identified by fid to the disk device. The operation is
    equivalent to calling sync() on the file system.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 hw/9pfs/virtio-9p-local.c |    9 +++++++++
 hw/9pfs/virtio-9p.c       |   31 +++++++++++++++++++++++++++++++
 hw/9pfs/virtio-9p.h       |    2 ++
 hw/file-op-9p.h           |    1 +
 4 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
index 0a015de..43ff37c 100644
--- a/hw/9pfs/virtio-9p-local.c
+++ b/hw/9pfs/virtio-9p-local.c
@@ -528,6 +528,14 @@ static int local_lremovexattr(FsContext *ctx,
     return v9fs_remove_xattr(ctx, path, name);
 }
 
+static int local_syncfs(FsContext *ctx, int fd)
+{
+    /*
+     * We should be doing per file system sync here.
+     */
+    sync();
+    return 0;
+}
 
 FileOperations local_ops = {
     .lstat = local_lstat,
@@ -560,4 +568,5 @@ FileOperations local_ops = {
     .llistxattr = local_llistxattr,
     .lsetxattr = local_lsetxattr,
     .lremovexattr = local_lremovexattr,
+    .syncfs     = local_syncfs,
 };
diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index c4b0198..ce09e55 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -299,6 +299,10 @@ static int v9fs_do_lremovexattr(V9fsState *s, V9fsString *path,
                                 xattr_name->data);
 }
 
+static int v9fs_do_syncfs(V9fsState *s, int fd)
+{
+    return s->ops->syncfs(&s->ctx, fd);
+}
 
 static void v9fs_string_init(V9fsString *str)
 {
@@ -1978,6 +1982,32 @@ static void v9fs_fsync(V9fsState *s, V9fsPDU *pdu)
     v9fs_post_do_fsync(s, pdu, err);
 }
 
+static void v9fs_post_do_syncfs(V9fsState *s, V9fsPDU *pdu, int err)
+{
+    if (err == -1) {
+        err = -errno;
+    }
+    complete_pdu(s, pdu, err);
+}
+
+static void v9fs_syncfs(V9fsState *s, V9fsPDU *pdu)
+{
+    int err;
+    int32_t fid;
+    size_t offset = 7;
+    V9fsFidState *fidp;
+
+    pdu_unmarshal(pdu, offset, "d", &fid);
+    fidp = lookup_fid(s, fid);
+    if (fidp == NULL) {
+        err = -ENOENT;
+        v9fs_post_do_syncfs(s, pdu, err);
+        return;
+    }
+    err = v9fs_do_syncfs(s, fidp->fsmap.fs.fd);
+    v9fs_post_do_syncfs(s, pdu, err);
+}
+
 static void v9fs_clunk(V9fsState *s, V9fsPDU *pdu)
 {
     int32_t fid;
@@ -3676,6 +3706,7 @@ static pdu_handler_t *pdu_handlers[] = {
     [P9_TWALK] = v9fs_walk,
     [P9_TCLUNK] = v9fs_clunk,
     [P9_TFSYNC] = v9fs_fsync,
+    [P9_TSYNCFS] = v9fs_syncfs,
     [P9_TOPEN] = v9fs_open,
     [P9_TREAD] = v9fs_read,
 #if 0
diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index 68d5906..b0f8210 100644
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -13,6 +13,8 @@
 #define VIRTIO_9P_MOUNT_TAG 0
 
 enum {
+    P9_TSYNCFS = 0,
+    P9_RSYNCFS,
     P9_TLERROR = 6,
     P9_RLERROR,
     P9_TSTATFS = 8,
diff --git a/hw/file-op-9p.h b/hw/file-op-9p.h
index 126e60e..e306305 100644
--- a/hw/file-op-9p.h
+++ b/hw/file-op-9p.h
@@ -94,6 +94,7 @@ typedef struct FileOperations
     int (*lsetxattr)(FsContext *, const char *,
                      const char *, void *, size_t, int);
     int (*lremovexattr)(FsContext *, const char *, const char *);
+    int (*syncfs)(FsContext *, int);
     void *opaque;
 } FileOperations;
 
-- 
1.7.1