Merge tag 'erofs-for-6.17-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:

 - Align FSDAX enablement among multiple devices

 - Fix EROFS_FS_ZIP_ACCEL build dependency again to prevent forcing
   CRYPTO{,_DEFLATE}=y even if EROFS=m

 - Fix atomic context detection to properly launch kworkers on demand

 - Fix block count statistics for 48-bit addressing support

* tag 'erofs-for-6.17-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: fix block count report when 48-bit layout is on
  erofs: fix atomic context detection when !CONFIG_DEBUG_LOCK_ALLOC
  erofs: Do not select tristate symbols from bool symbols
  erofs: Fallback to normal access if DAX is not supported on extra device

Author: torvalds

fs/erofs/Kconfig

@@ -3,8 +3,18 @@
 config EROFS_FS
 	tristate "EROFS filesystem support"
 	depends on BLOCK
+	select CACHEFILES if EROFS_FS_ONDEMAND
 	select CRC32
+	select CRYPTO if EROFS_FS_ZIP_ACCEL
+	select CRYPTO_DEFLATE if EROFS_FS_ZIP_ACCEL
 	select FS_IOMAP
+	select LZ4_DECOMPRESS if EROFS_FS_ZIP
+	select NETFS_SUPPORT if EROFS_FS_ONDEMAND
+	select XXHASH if EROFS_FS_XATTR
+	select XZ_DEC if EROFS_FS_ZIP_LZMA
+	select XZ_DEC_MICROLZMA if EROFS_FS_ZIP_LZMA
+	select ZLIB_INFLATE if EROFS_FS_ZIP_DEFLATE
+	select ZSTD_DECOMPRESS if EROFS_FS_ZIP_ZSTD
 	help
 	  EROFS (Enhanced Read-Only File System) is a lightweight read-only
 	  file system with modern designs (e.g. no buffer heads, inline
@@ -38,7 +48,6 @@ config EROFS_FS_DEBUG
 config EROFS_FS_XATTR
 	bool "EROFS extended attributes"
 	depends on EROFS_FS
-	select XXHASH
 	default y
 	help
 	  Extended attributes are name:value pairs associated with inodes by
@@ -94,7 +103,6 @@ config EROFS_FS_BACKED_BY_FILE
 config EROFS_FS_ZIP
 	bool "EROFS Data Compression Support"
 	depends on EROFS_FS
-	select LZ4_DECOMPRESS
 	default y
 	help
 	  Enable transparent compression support for EROFS file systems.
@@ -104,8 +112,6 @@ config EROFS_FS_ZIP
 config EROFS_FS_ZIP_LZMA
 	bool "EROFS LZMA compressed data support"
 	depends on EROFS_FS_ZIP
-	select XZ_DEC
-	select XZ_DEC_MICROLZMA
 	help
 	  Saying Y here includes support for reading EROFS file systems
 	  containing LZMA compressed data, specifically called microLZMA. It
@@ -117,7 +123,6 @@ config EROFS_FS_ZIP_LZMA
 config EROFS_FS_ZIP_DEFLATE
 	bool "EROFS DEFLATE compressed data support"
 	depends on EROFS_FS_ZIP
-	select ZLIB_INFLATE
 	help
 	  Saying Y here includes support for reading EROFS file systems
 	  containing DEFLATE compressed data.  It gives better compression
@@ -132,7 +137,6 @@ config EROFS_FS_ZIP_DEFLATE
 config EROFS_FS_ZIP_ZSTD
 	bool "EROFS Zstandard compressed data support"
 	depends on EROFS_FS_ZIP
-	select ZSTD_DECOMPRESS
 	help
 	  Saying Y here includes support for reading EROFS file systems
 	  containing Zstandard compressed data.  It gives better compression
@@ -147,8 +151,6 @@ config EROFS_FS_ZIP_ZSTD
 config EROFS_FS_ZIP_ACCEL
 	bool "EROFS hardware decompression support"
 	depends on EROFS_FS_ZIP
-	select CRYPTO
-	select CRYPTO_DEFLATE
 	help
 	  Saying Y here includes hardware accelerator support for reading
 	  EROFS file systems containing compressed data.  It gives better
@@ -163,9 +165,7 @@ config EROFS_FS_ZIP_ACCEL
 config EROFS_FS_ONDEMAND
 	bool "EROFS fscache-based on-demand read support (deprecated)"
 	depends on EROFS_FS
-	select NETFS_SUPPORT
 	select FSCACHE
-	select CACHEFILES
 	select CACHEFILES_ONDEMAND
 	help
 	  This permits EROFS to use fscache-backed data blobs with on-demand

fs/erofs/super.c

@@ -174,6 +174,11 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 		if (!erofs_is_fileio_mode(sbi)) {
 			dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),
 					&dif->dax_part_off, NULL, NULL);
+			if (!dif->dax_dev && test_opt(&sbi->opt, DAX_ALWAYS)) {
+				erofs_info(sb, "DAX unsupported by %s. Turning off DAX.",
+					   dif->path);
+				clear_opt(&sbi->opt, DAX_ALWAYS);
+			}
 		} else if (!S_ISREG(file_inode(file)->i_mode)) {
 			fput(file);
 			return -EINVAL;
@@ -210,8 +215,13 @@ static int erofs_scan_devices(struct super_block *sb,
 			  ondisk_extradevs, sbi->devs->extra_devices);
 		return -EINVAL;
 	}
-	if (!ondisk_extradevs)
+	if (!ondisk_extradevs) {
+		if (test_opt(&sbi->opt, DAX_ALWAYS) && !sbi->dif0.dax_dev) {
+			erofs_info(sb, "DAX unsupported by block device. Turning off DAX.");
+			clear_opt(&sbi->opt, DAX_ALWAYS);
+		}
 		return 0;
+	}
 
 	if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
 		sbi->devs->flatdev = true;
@@ -313,8 +323,8 @@ static int erofs_read_superblock(struct super_block *sb)
 	sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
 	if (erofs_sb_has_48bit(sbi) && dsb->rootnid_8b) {
 		sbi->root_nid = le64_to_cpu(dsb->rootnid_8b);
-		sbi->dif0.blocks = (sbi->dif0.blocks << 32) |
-				le16_to_cpu(dsb->rb.blocks_hi);
+		sbi->dif0.blocks = sbi->dif0.blocks |
+				((u64)le16_to_cpu(dsb->rb.blocks_hi) << 32);
 	} else {
 		sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b);
 	}
@@ -338,7 +348,6 @@ static int erofs_read_superblock(struct super_block *sb)
 	if (ret < 0)
 		goto out;
 
-	/* handle multiple devices */
 	ret = erofs_scan_devices(sb, dsb);
 
 	if (erofs_sb_has_48bit(sbi))
@@ -671,14 +680,9 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 			return invalfc(fc, "cannot use fsoffset in fscache mode");
 	}
 
-	if (test_opt(&sbi->opt, DAX_ALWAYS)) {
-		if (!sbi->dif0.dax_dev) {
-			errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
-			clear_opt(&sbi->opt, DAX_ALWAYS);
-		} else if (sbi->blkszbits != PAGE_SHIFT) {
-			errorfc(fc, "unsupported blocksize for DAX");
-			clear_opt(&sbi->opt, DAX_ALWAYS);
-		}
+	if (test_opt(&sbi->opt, DAX_ALWAYS) && sbi->blkszbits != PAGE_SHIFT) {
+		erofs_info(sb, "unsupported blocksize for DAX");
+		clear_opt(&sbi->opt, DAX_ALWAYS);
 	}
 
 	sb->s_time_gran = 1;

fs/erofs/zdata.c

@@ -1432,6 +1432,16 @@ static void z_erofs_decompressqueue_kthread_work(struct kthread_work *work)
 }
 #endif
 
+/* Use (kthread_)work in atomic contexts to minimize scheduling overhead */
+static inline bool z_erofs_in_atomic(void)
+{
+	if (IS_ENABLED(CONFIG_PREEMPTION) && rcu_preempt_depth())
+		return true;
+	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+		return true;
+	return !preemptible();
+}
+
 static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
 				       int bios)
 {
@@ -1446,8 +1456,7 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
 
 	if (atomic_add_return(bios, &io->pending_bios))
 		return;
-	/* Use (kthread_)work and sync decompression for atomic contexts only */
-	if (!in_task() || irqs_disabled() || rcu_read_lock_any_held()) {
+	if (z_erofs_in_atomic()) {
 #ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
 		struct kthread_worker *worker;