LU-9771 flr: mirror read and write

[fs/lustre-release.git] / lustre / llite / file.c

diff --git a/lustre/llite/file.c b/lustre/llite/file.c
index 96115bd..12e73eb 100644 (file)
--- a/lustre/llite/file.c
+++ b/lustre/llite/file.c
@@ -1066,6 +1066,29 @@ out_size_unlock:
        RETURN(rc);
 }
 
+/**
+ * Set designated mirror for I/O.
+ *
+ * So far only read, write, and truncated can support to issue I/O to
+ * designated mirror.
+ */
+void ll_io_set_mirror(struct cl_io *io, const struct file *file)
+{
+       struct ll_file_data *fd = LUSTRE_FPRIVATE(file);
+
+       /* FLR: disable non-delay for designated mirror I/O because obviously
+        * only one mirror is available */
+       if (fd->fd_designated_mirror > 0) {
+               io->ci_ndelay = 0;
+               io->ci_designated_mirror = fd->fd_designated_mirror;
+               io->ci_pio = 0; /* doesn't have a mechanism to pass mirror
+                                * io to ptasks */
+       }
+
+       CDEBUG(D_VFSTRACE, "%s: desiginated mirror: %d\n",
+              file->f_path.dentry->d_name.name, io->ci_designated_mirror);
+}
+
 static bool file_is_noatime(const struct file *file)
 {
        const struct vfsmount *mnt = file->f_path.mnt;
@@ -1130,6 +1153,8 @@ static void ll_io_init(struct cl_io *io, struct file *file, enum cl_io_type iot)
        /* FLR: only use non-delay I/O for read as there is only one
         * avaliable mirror for write. */
        io->ci_ndelay = !(iot == CIT_WRITE);
+
+       ll_io_set_mirror(io, file);
 }
 
 static int ll_file_io_ptask(struct cfs_ptask *ptask)
@@ -3191,6 +3216,15 @@ out_ladvise:
                OBD_FREE(k_ladvise_hdr, alloc_size);
                RETURN(rc);
        }
+       case LL_IOC_FLR_SET_MIRROR: {
+               /* mirror I/O must be direct to avoid polluting page cache
+                * by stale data. */
+               if (!(file->f_flags & O_DIRECT))
+                       RETURN(-EINVAL);
+
+               fd->fd_designated_mirror = (__u32)arg;
+               RETURN(0);
+       }
        case LL_IOC_FSGETXATTR:
                RETURN(ll_ioctl_fsgetxattr(inode, cmd, arg));
        case LL_IOC_FSSETXATTR: