erofs: enable 48-bit layout support

Both 48-bit block addressing and encoded extents are implemented,
let's enable them formally.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250310095625.2623817-1-hsiangkao@linux.alibaba.com

Author: hsiangkao

fs/erofs/Kconfig

@@ -13,12 +13,12 @@ config EROFS_FS
 	  smartphones with Android OS, LiveCDs and high-density hosts with
 	  numerous containers;
 
-	  It also provides fixed-sized output compression support in order to
-	  improve storage density as well as keep relatively higher compression
-	  ratios and implements in-place decompression to reuse the file page
-	  for compressed data temporarily with proper strategies, which is
-	  quite useful to ensure guaranteed end-to-end runtime decompression
-	  performance under extremely memory pressure without extra cost.
+	  It also provides transparent compression and deduplication support to
+	  improve storage density and maintain relatively high compression
+	  ratios, and it implements in-place decompression to temporarily reuse
+	  page cache for compressed data using proper strategies, which is
+	  quite useful for ensuring guaranteed end-to-end runtime decompression
+	  performance under extreme memory pressure without extra cost.
 
 	  See the documentation at <file:Documentation/filesystems/erofs.rst>
 	  and the web pages at <https://erofs.docs.kernel.org> for more details.
@@ -97,7 +97,7 @@ config EROFS_FS_ZIP
 	select LZ4_DECOMPRESS
 	default y
 	help
-	  Enable fixed-sized output compression for EROFS.
+	  Enable transparent compression support for EROFS file systems.
 
 	  If you don't want to enable compression feature, say N.
 

fs/erofs/erofs_fs.h

@@ -32,7 +32,7 @@
 #define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES	0x00000040
 #define EROFS_FEATURE_INCOMPAT_48BIT		0x00000080
 #define EROFS_ALL_FEATURE_INCOMPAT		\
-	((EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES << 1) - 1)
+	((EROFS_FEATURE_INCOMPAT_48BIT << 1) - 1)
 
 #define EROFS_SB_EXTSLOT_SIZE	16
 

fs/erofs/super.c

@@ -330,6 +330,8 @@ static int erofs_read_superblock(struct super_block *sb)
 	/* handle multiple devices */
 	ret = erofs_scan_devices(sb, dsb);
 
+	if (erofs_sb_has_48bit(sbi))
+		erofs_info(sb, "EXPERIMENTAL 48-bit layout support in use. Use at your own risk!");
 	if (erofs_is_fscache_mode(sb))
 		erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!");
 out: