diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 4698a5c553dc010fa0aedabe3f3f4e0fb68b65c8..44e4fe9fba026e9a6c0a49d68b3505a9b1122a32 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -643,7 +643,8 @@ again:
 
 	if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
 	    (iocb->ki_filp->f_flags & O_DIRECT) ||
-	    (inode->i_sb->s_flags & MS_SYNCHRONOUS))
+	    (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
+	    (fi->flags & CEPH_F_SYNC))
 		/* hmm, this isn't really async... */
 		ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
 	else
@@ -720,7 +721,8 @@ retry_snap:
 
 	if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
 	    (iocb->ki_filp->f_flags & O_DIRECT) ||
-	    (inode->i_sb->s_flags & MS_SYNCHRONOUS)) {
+	    (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
+	    (fi->flags & CEPH_F_SYNC)) {
 		ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
 			&iocb->ki_pos);
 	} else {
diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
index ef0b5f48e13ac77a75233a40634d000068c9a21c..a757a5680578df3d08a6e0f974f110a502cb6f98 100644
--- a/fs/ceph/ioctl.c
+++ b/fs/ceph/ioctl.c
@@ -231,6 +231,14 @@ static long ceph_ioctl_lazyio(struct file *file)
 	return 0;
 }
 
+static long ceph_ioctl_syncio(struct file *file)
+{
+	struct ceph_file_info *fi = file->private_data;
+
+	fi->flags |= CEPH_F_SYNC;
+	return 0;
+}
+
 long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	dout("ioctl file %p cmd %u arg %lu\n", file, cmd, arg);
@@ -249,6 +257,9 @@ long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
 	case CEPH_IOC_LAZYIO:
 		return ceph_ioctl_lazyio(file);
+
+	case CEPH_IOC_SYNCIO:
+		return ceph_ioctl_syncio(file);
 	}
 
 	return -ENOTTY;
diff --git a/fs/ceph/ioctl.h b/fs/ceph/ioctl.h
index 52e8fd74d450b9e2895eb7c29d80e38b77eb0807..0c5167e43180c9a0f41b24f39a35b0a4e5de1246 100644
--- a/fs/ceph/ioctl.h
+++ b/fs/ceph/ioctl.h
@@ -40,5 +40,6 @@ struct ceph_ioctl_dataloc {
 				   struct ceph_ioctl_dataloc)
 
 #define CEPH_IOC_LAZYIO _IO(CEPH_IOCTL_MAGIC, 4)
+#define CEPH_IOC_SYNCIO _IO(CEPH_IOCTL_MAGIC, 5)
 
 #endif
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 8febe6fce2b1f715f094da8c8db7c764a0880ea5..cdb17d36755c4a67ade569afb16a724031cc2530 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -543,6 +543,8 @@ extern void ceph_reservation_status(struct ceph_fs_client *client,
 /*
  * we keep buffered readdir results attached to file->private_data
  */
+#define CEPH_F_SYNC     1
+
 struct ceph_file_info {
 	short fmode;     /* initialized on open */
 	short flags;     /* CEPH_F_* */