git: c61ee49cd06a - main - loader: zstd based filesystem, zstdfs like gzipfs

The branch main has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=c61ee49cd06a610193493f033f04d38cf61f11e2

commit c61ee49cd06a610193493f033f04d38cf61f11e2
Author:     Warner Losh <imp@FreeBSD.org>
AuthorDate: 2026-07-11 14:46:19 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2026-07-11 19:28:47 +0000

    loader: zstd based filesystem, zstdfs like gzipfs
    
    Off by default.
    
    Sponsored by:           Netflix
---
 stand/efi/loader/conf.c        |  1 +
 stand/i386/loader/conf.c       |  1 +
 stand/kboot/kboot/conf.c       |  4 ++++
 stand/libsa/Makefile           |  6 ++++++
 stand/libsa/libsa.3            | 14 ++++++++++++++
 stand/libsa/stand.h            |  1 +
 stand/userboot/userboot/conf.c |  1 +
 7 files changed, 28 insertions(+)

diff --git a/stand/efi/loader/conf.c b/stand/efi/loader/conf.c
index 4f257dc5ba23..30d9b95739e8 100644
--- a/stand/efi/loader/conf.c
+++ b/stand/efi/loader/conf.c
@@ -57,6 +57,7 @@ struct devsw *devsw[] = {
 struct fs_ops *file_system[] = {
 #ifdef EFI_ZFS_BOOT
 	&zfs_fsops,
+	&zstdfs_fsops,
 #endif
 	&dosfs_fsops,
 	&ufs_fsops,
diff --git a/stand/i386/loader/conf.c b/stand/i386/loader/conf.c
index 643990699ca1..3360c2722035 100644
--- a/stand/i386/loader/conf.c
+++ b/stand/i386/loader/conf.c
@@ -62,6 +62,7 @@ struct devsw *devsw[] = {
 struct fs_ops *file_system[] = {
 #if defined(LOADER_ZFS_SUPPORT)
     &zfs_fsops,
+    &zstdfs_fsops,
 #endif
 #if defined(LOADER_UFS_SUPPORT)
     &ufs_fsops,
diff --git a/stand/kboot/kboot/conf.c b/stand/kboot/kboot/conf.c
index 5d384c5270e6..03c3ea750e76 100644
--- a/stand/kboot/kboot/conf.c
+++ b/stand/kboot/kboot/conf.c
@@ -85,11 +85,15 @@ struct fs_ops *file_system[] = {
 #if defined(LOADER_BZIP2_SUPPORT)
     &bzipfs_fsops,
 #endif
+#if defined(LOADER_XZ_SUPPORT)
+    &xzfs_fsops,
+#endif
 #if defined(LOADER_MSDOS_SUPPORT)
     &dosfs_fsops,
 #endif
 #if defined(LOADER_ZFS_SUPPORT)
 	&zfs_fsops,
+	&zstdfs_fsops,
 #endif
     &hostfs_fsops,
     NULL
diff --git a/stand/libsa/Makefile b/stand/libsa/Makefile
index 2bb33060ee2a..173dec69657d 100644
--- a/stand/libsa/Makefile
+++ b/stand/libsa/Makefile
@@ -192,6 +192,12 @@ SRCS+=	g_eli_hmac.c pkcs5v2.c
 # Maybe ZFS
 .if ${MK_LOADER_ZFS} == "yes"
 .include "${SASRC}/zfs/Makefile.inc"
+
+# zstdfs.c is a stacked filesystem for .zst files, like gzipfs.c/bzipfs.c
+# above; it's only buildable here because zfs/Makefile.inc already pulled
+# the zstd decompressor in for ZFS's on-disk compression.
+SRCS+=	zstdfs.c
+CFLAGS.zstdfs.c+= ${ZSTD_CFLAGS}
 .endif
 
 # Crypto hashing functions
diff --git a/stand/libsa/libsa.3 b/stand/libsa/libsa.3
index 0947f97a0a1f..a44588901f8b 100644
--- a/stand/libsa/libsa.3
+++ b/stand/libsa/libsa.3
@@ -781,6 +781,20 @@ The same as
 but for
 .Xr bzip2 1 Ns -compressed
 files.
+.It Va xzfs_fsops
+The same as
+.Va gzipfs_fsops ,
+but for
+.Xr xz 1 Ns -compressed
+files.
+.It Va zstdfs_fsops
+The same as
+.Va gzipfs_fsops ,
+but for
+.Xr zstd 1 Ns -compressed
+files.
+Only available when built with ZFS support, since that is the only
+source of the zstd decompressor in the boot loader environment.
 .It Va pkgfs_fsops
 File access from a tar file typically streamed via TFTP.
 The order of files in the tar file must match the order they are
diff --git a/stand/libsa/stand.h b/stand/libsa/stand.h
index 3cb227ce2079..6e363b145595 100644
--- a/stand/libsa/stand.h
+++ b/stand/libsa/stand.h
@@ -131,6 +131,7 @@ extern struct fs_ops cd9660_fsops;
 extern struct fs_ops gzipfs_fsops;
 extern struct fs_ops bzipfs_fsops;
 extern struct fs_ops xzfs_fsops;
+extern struct fs_ops zstdfs_fsops;
 extern struct fs_ops dosfs_fsops;
 extern struct fs_ops ext2fs_fsops;
 extern struct fs_ops splitfs_fsops;
diff --git a/stand/userboot/userboot/conf.c b/stand/userboot/userboot/conf.c
index 8d37f241c9bf..662f4e405f0a 100644
--- a/stand/userboot/userboot/conf.c
+++ b/stand/userboot/userboot/conf.c
@@ -67,6 +67,7 @@ struct fs_ops *file_system[] = {
 	&cd9660_fsops,
 #if defined(USERBOOT_ZFS_SUPPORT)
 	&zfs_fsops,
+	&zstdfs_fsops,
 #endif
 	&gzipfs_fsops,
 	&bzipfs_fsops,