BRT: Move zfs_bclone_enabled and zfs_bclone_wait_dirty tunables

Relocate declaration of zfs_bclone_enabled and zfs_bclone_wait_dirty
to the platform independant code.  Add some additional documention
to these tunables at the same time.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

include/os/freebsd/zfs/sys/zfs_vfsops_os.h

@@ -285,7 +285,6 @@ typedef struct zfid_long {
 #define	LONG_FID_LEN	(sizeof (zfid_long_t) - sizeof (uint16_t))
 
 extern int zfs_super_owner;
-extern int zfs_bclone_enabled;
 
 extern void zfs_init(void);
 extern void zfs_fini(void);

include/os/linux/zfs/sys/zfs_vfsops_os.h

@@ -45,9 +45,6 @@ extern "C" {
 typedef struct zfsvfs zfsvfs_t;
 struct znode;
 
-extern int zfs_bclone_enabled;
-extern int zfs_bclone_wait_dirty;
-
 /*
  * This structure emulates the vfs_t from other platforms.  It's purpose
  * is to facilitate the handling of mount options and minimize structural

include/sys/zfs_vnops.h

@@ -24,8 +24,11 @@
 
 #ifndef	_SYS_FS_ZFS_VNOPS_H
 #define	_SYS_FS_ZFS_VNOPS_H
+
 #include <sys/zfs_vnops_os.h>
 
+extern int zfs_bclone_enabled;
+
 extern int zfs_fsync(znode_t *, int, cred_t *);
 extern int zfs_read(znode_t *, zfs_uio_t *, int, cred_t *);
 extern int zfs_write(znode_t *, zfs_uio_t *, int, cred_t *);

module/os/freebsd/zfs/zfs_vfsops.c

@@ -89,14 +89,6 @@ int zfs_debug_level;
 SYSCTL_INT(_vfs_zfs, OID_AUTO, debug, CTLFLAG_RWTUN, &zfs_debug_level, 0,
 	"Debug level");
 
-int zfs_bclone_enabled = 1;
-SYSCTL_INT(_vfs_zfs, OID_AUTO, bclone_enabled, CTLFLAG_RWTUN,
-	&zfs_bclone_enabled, 0, "Enable block cloning");
-
-int zfs_bclone_wait_dirty = 0;
-SYSCTL_INT(_vfs_zfs, OID_AUTO, bclone_wait_dirty, CTLFLAG_RWTUN,
-	&zfs_bclone_wait_dirty, 0, "Wait for dirty blocks when cloning");
-
 struct zfs_jailparam {
 	int mount_snapshot;
 };

module/os/linux/zfs/zfs_vnops_os.c

@@ -4255,13 +4255,4 @@ EXPORT_SYMBOL(zfs_map);
 /* CSTYLED */
 module_param(zfs_delete_blocks, ulong, 0644);
 MODULE_PARM_DESC(zfs_delete_blocks, "Delete files larger than N blocks async");
-
-/* CSTYLED */
-module_param(zfs_bclone_enabled, int, 0644);
-MODULE_PARM_DESC(zfs_bclone_enabled, "Enable block cloning");
-
-/* CSTYLED */
-module_param(zfs_bclone_wait_dirty, int, 0644);
-MODULE_PARM_DESC(zfs_bclone_wait_dirty, "Wait for dirty blocks when cloning");
-
 #endif

module/os/linux/zfs/zpl_file_range.c

@@ -31,9 +31,6 @@
 #include <sys/zfs_vnops.h>
 #include <sys/zfeature.h>
 
-int zfs_bclone_enabled = 1;
-int zfs_bclone_wait_dirty = 0;
-
 /*
  * Clone part of a file via block cloning.
  *

module/zfs/zfs_vnops.c

@@ -58,6 +58,26 @@
 #include <sys/zfs_vfsops.h>
 #include <sys/zfs_znode.h>
 
+/*
+ * Enable the experimental block cloning feature.  If this setting is 0, then
+ * even if feature@block_cloning is enabled, attempts to clone blocks will act
+ * as though the feature is disabled.
+ */
+int zfs_bclone_enabled = 1;
+
+/*
+ * When set zfs_clone_range() waits for dirty data to be written to disk.
+ * This allows the clone operation to reliably succeed when a file is modified
+ * and then immediately cloned. For small files this may be slower than making
+ * a copy of the file and is therefore not the default.  However, in certain
+ * scenarios this behavior may be desirable so a tunable is provided.
+ */
+static int zfs_bclone_wait_dirty = 0;
+
+/*
+ * Maximum bytes to read per chunk in zfs_read().
+ */
+static uint64_t zfs_vnops_read_chunk_size = 1024 * 1024;
 
 int
 zfs_fsync(znode_t *zp, int syncflag, cred_t *cr)
@@ -182,8 +202,6 @@ zfs_access(znode_t *zp, int mode, int flag, cred_t *cr)
 	return (error);
 }
 
-static uint64_t zfs_vnops_read_chunk_size = 1024 * 1024; /* Tunable */
-
 /*
  * Read bytes from specified file into supplied buffer.
  *
@@ -1526,3 +1544,9 @@ EXPORT_SYMBOL(zfs_clone_range_replay);
 
 ZFS_MODULE_PARAM(zfs_vnops, zfs_vnops_, read_chunk_size, U64, ZMOD_RW,
 	"Bytes to read per chunk");
+
+ZFS_MODULE_PARAM(zfs, zfs_, bclone_enabled, INT, ZMOD_RW,
+	"Enable block cloning");
+
+ZFS_MODULE_PARAM(zfs, zfs_, bclone_wait_dirty, INT, ZMOD_RW,
+	"Wait for dirty blocks when cloning");