FreeBSD: bring back possibility to rewind the checkpoint from bootloader

Add parsing of the rewind options.

When I was upstreaming the change [1], I omitted the part where we
detect that the pool should be rewind. When the FreeBSD repo has
synced with the OpenZFS, this part of the code was removed.

[1] FreeBSD repo: 277f38abffc6a8160b5044128b5b2c620fbb970c
[2] OpenZFS repo: f2c027bd6a003ec5793f8716e6189c389c60f47a

External-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254152
Originally reviewed by: tsoome, allanjude
Originally reviewed by: kevans (ok from high-level overview)
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mariusz Zaborski <oshogbo@vexillium.org>
Closes #11730

diff --git a/module/os/freebsd/zfs/zfs_vfsops.c b/module/os/freebsd/zfs/zfs_vfsops.c
index 7bc6b83d0272e90d8e73b96766f73bc33d94e79a..a537342f9678d5383a9e791311629da9dcedb54a 100644 (file)
--- a/module/os/freebsd/zfs/zfs_vfsops.c
+++ b/module/os/freebsd/zfs/zfs_vfsops.c
@@ -1291,6 +1291,18 @@ getpoolname(const char *osname, char *poolname)
        return (0);
 }
 
+static void
+fetch_osname_options(char *name, bool *checkpointrewind)
+{
+
+       if (name[0] == '!') {
+               *checkpointrewind = true;
+               memmove(name, name + 1, strlen(name));
+       } else {
+               *checkpointrewind = false;
+       }
+}
+
 /*ARGSUSED*/
 static int
 zfs_mount(vfs_t *vfsp)
@@ -1301,6 +1313,7 @@ zfs_mount(vfs_t *vfsp)
        char            *osname;
        int             error = 0;
        int             canwrite;
+       bool            checkpointrewind;
 
        if (vfs_getopt(vfsp->mnt_optnew, "from", (void **)&osname, NULL))
                return (SET_ERROR(EINVAL));
@@ -1314,6 +1327,8 @@ zfs_mount(vfs_t *vfsp)
                secpolicy_fs_mount_clearopts(cr, vfsp);
        }
 
+       fetch_osname_options(osname, &checkpointrewind);
+
        /*
         * Check for mount privilege?
         *
@@ -1392,7 +1407,7 @@ zfs_mount(vfs_t *vfsp)
 
                error = getpoolname(osname, pname);
                if (error == 0)
-                       error = spa_import_rootpool(pname, false);
+                       error = spa_import_rootpool(pname, checkpointrewind);
                if (error)
                        goto out;
        }