Fix lower dataset mounts and reparse point parsing

Additionally, correct the reparse point ID
returned by directory listings.

Signed-off-by: Jorgen Lundman <[email protected]>

module/os/windows/zfs/zfs_vnops_windows.c

@@ -415,7 +415,19 @@ stream_parse(char *filename, char **streamname)
  * - HOLD on dvp
  * - HOLD on vp
  * - final parsed filename part in 'lastname' (in the case of creating an entry)
+ *
+ * IRP_MJ_CREATE calls
+ *
+ * zfsvfs  Filename
+ * --------------------------------------------------------
+ * IRP_MJ_CREATE(pool, "/lower/today.txt")
+ *     : lookup "lower", return STATUS_REPARSE
+ *     : Set unparsed length rdp->Reserved = 10 ("/today.txt") * 2
+ * --------------------------------------------------------
+ * IRP_MJ_CREATE(lower, "/today.txt")
+ *     : lookup "today.txt", return SUCCESS
  */
+
 int
 zfs_find_dvp_vp(zfsvfs_t *zfsvfs, char *filename, int finalpartmaynotexist,
     int finalpartmustnotexist, char **lastname, struct vnode **dvpp,
@@ -506,29 +518,29 @@ zfs_find_dvp_vp(zfsvfs_t *zfsvfs, char *filename, int finalpartmaynotexist,
 		vp = ZTOV(zp);
 		ASSERT(zp != NULL);
 
-
 		/*
 		 * If we come across a REPARSE, we stop processing here
 		 * and pass the "zp" back for caller to do more processing,
 		 * which might include returning "zp" (FILE_OPEN_REPARSE_POINT)
 		 * and ReparseTag.
-		 * But, if IRP->zfsvfs is the same as zp->zfsvfs, the lookup
-		 * was already requested for "us" specifically, so keep going.
-		 * This could fail with nested dirmounts? Only check lowest
-		 * directory to bail.
+		 * If they requested FileOpenReparsePoint, AND we are at the
+		 * final-part, we open it normally.
+		 * Other cases we need to ask for redriving the query
 		 */
-		if ((zp->z_pflags & ZFS_REPARSE) &&
-		    (zfsvfs != zp->z_zfsvfs)) {
 
-			// Indicate if reparse was final part
+		if (zp->z_pflags & ZFS_REPARSE) {
+			/*
+			 * Indicate if reparse was final part,
+			 * caller will handle this case
+			 */
 			if (lastname)
 				*lastname = brkt;
 
 			if (dvpp != NULL)
 				*dvpp = dvp;
 			if (vpp != NULL)
 				*vpp = vp;
-			// VN_RELE(dvp);
+
 			return (STATUS_REPARSE);
 		}
 
@@ -968,9 +980,6 @@ zfs_vnop_lookup_impl(PIRP Irp, PIO_STACK_LOCATION IrpSp, mount_t *zmo,
 	    (!finalname || !*finalname))
 		error = STATUS_SUCCESS;
 
-	if (error == STATUS_REPARSE && !FileOpenReparsePoint)
-		error = STATUS_IO_REPARSE_TAG_NOT_HANDLED;
-
 	if (error) {
 
 		/*
@@ -1002,12 +1011,16 @@ zfs_vnop_lookup_impl(PIRP Irp, PIO_STACK_LOCATION IrpSp, mount_t *zmo,
 			    size, '!FSZ');
 			get_reparse_point_impl(zp, rpb, size);
 
-			// Return in Reserved the amount of path
-			// that was parsed.
-			/* FileObject->FileName.Length - parsed */
-			rpb->Reserved = (outlen -
-			    ((finalname - filename) +
-			    strlen(finalname))) * sizeof (WCHAR);
+			/*
+			 * Length, in bytes, of the unparsed portion of the
+			 * file name pointed to by the FileName member of the
+			 * associated file object.
+			 * Should include the leading "/", when finalname
+			 * here would be "lower".
+			 */
+			rpb->Reserved = strlen(finalname) * sizeof (WCHAR);
+			if (rpb->Reserved != 0)
+				rpb->Reserved += sizeof (WCHAR); // the slash
 
 			dprintf("%s: returning REPARSE\n", __func__);
 			Irp->IoStatus.Information = rpb->ReparseTag;

module/os/windows/zfs/zfs_vnops_windows_lib.c

@@ -845,6 +845,10 @@ zfs_readdir_emitdir(zfsvfs_t *zfsvfs, const char *name, emitdir_ptr_t *ctx,
 		// Is it worth warning about failed lookup here?
 	}
 
+	ULONG reparse_tag = 0;
+	if (tzp->z_pflags & ZFS_REPARSE)
+		reparse_tag = get_reparse_tag(tzp);
+
 	structsize = 0; /* size of win struct desired */
 	/* bufptr : output memory area, incrementing */
 	/* outcount : amount written to output, incrementing */
@@ -883,7 +887,7 @@ zfs_readdir_emitdir(zfsvfs_t *zfsvfs, const char *name, emitdir_ptr_t *ctx,
 		// Magic code to change dir icon to link
 		eodp->EaSize =
 		    tzp->z_pflags & ZFS_REPARSE ?
-		    0xa0000003 :
+		    reparse_tag :
 		    xattr_getsize(ZTOV(tzp));
 		eodp->FileAttributes =
 		    zfs_getwinflags(tzp);
@@ -921,7 +925,7 @@ zfs_readdir_emitdir(zfsvfs_t *zfsvfs, const char *name, emitdir_ptr_t *ctx,
 		    fibdi->LastAccessTime.QuadPart);
 		fibdi->EaSize =
 		    tzp->z_pflags & ZFS_REPARSE ?
-		    0xa0000003 :
+		    reparse_tag :
 		    xattr_getsize(ZTOV(tzp));
 		fibdi->FileAttributes =
 		    zfs_getwinflags(tzp);
@@ -961,7 +965,7 @@ zfs_readdir_emitdir(zfsvfs_t *zfsvfs, const char *name, emitdir_ptr_t *ctx,
 		    fbdi->LastAccessTime.QuadPart);
 		fbdi->EaSize =
 		    tzp->z_pflags & ZFS_REPARSE ?
-		    0xa0000003 :
+		    reparse_tag :
 		    xattr_getsize(ZTOV(tzp));
 		fbdi->FileAttributes =
 		    zfs_getwinflags(tzp);
@@ -1052,7 +1056,7 @@ zfs_readdir_emitdir(zfsvfs_t *zfsvfs, const char *name, emitdir_ptr_t *ctx,
 		    fifdi->LastAccessTime.QuadPart);
 		fifdi->EaSize =
 		    tzp->z_pflags & ZFS_REPARSE ?
-		    0xa0000003 :
+		    reparse_tag :
 		    xattr_getsize(ZTOV(tzp));
 		fifdi->FileAttributes =
 		    zfs_getwinflags(tzp);
@@ -1090,11 +1094,8 @@ zfs_readdir_emitdir(zfsvfs_t *zfsvfs, const char *name, emitdir_ptr_t *ctx,
 		TIME_UNIX_TO_WINDOWS(tzp->z_atime,
 		    fiedi->LastAccessTime.QuadPart);
 		fiedi->EaSize =
-		    tzp->z_pflags & ZFS_REPARSE ?
-		    0xa0000003 :
 		    xattr_getsize(ZTOV(tzp));
-		fiedi->FileAttributes =
-		    zfs_getwinflags(tzp);
+		fiedi->ReparsePointTag = reparse_tag;
 		RtlCopyMemory(&fiedi->FileId.Identifier[0], &tzp->z_id,
 		    sizeof (UINT64));
 		guid = dmu_objset_fsid_guid(zfsvfs->z_os);
@@ -1134,9 +1135,7 @@ zfs_readdir_emitdir(zfsvfs_t *zfsvfs, const char *name, emitdir_ptr_t *ctx,
 		    fiebdi->LastAccessTime.QuadPart);
 		fiebdi->EaSize =
 		    xattr_getsize(ZTOV(tzp));
-		fiebdi->ReparsePointTag =
-		    tzp->z_pflags & ZFS_REPARSE ?
-		    get_reparse_tag(tzp) : 0;
+		fiebdi->ReparsePointTag = reparse_tag;
 		fiebdi->FileAttributes =
 		    zfs_getwinflags(tzp);
 		fiebdi->ShortNameLength = 0;