Merge tag 'erofs-for-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs updates from Gao Xiang:
 "There are some new features available for this cycle. Firstly, EROFS
  LZMA algorithm support, specifically called MicroLZMA, is available as
  an option for embedded devices, LiveCDs and/or as the secondary
  auxiliary compression algorithm besides the primary algorithm in one
  file.

  In order to better support the LZMA fixed-sized output compression,
  especially for 4KiB pcluster size (which has lowest memory pressure
  thus useful for memory-sensitive scenarios), Lasse introduced a new
  LZMA header/container format called MicroLZMA to minimize the original
  LZMA1 header (for example, we don't need to waste 4-byte dictionary
  size and another 8-byte uncompressed size, which can be calculated by
  fs directly, for each pcluster) and enable EROFS fixed-sized output
  compression.

  Note that MicroLZMA can also be later used by other things in addition
  to EROFS too where wasting minimal amount of space for headers is
  important and it can be only compiled by enabling XZ_DEC_MICROLZMA.
  MicroLZMA has been supported by the latest upstream XZ embedded [1] &
  XZ utils [2], apply the latest related XZ embedded upstream patches by
  the XZ author Lasse here.

  Secondly, multiple device is also supported in this cycle, which is
  designed for multi-layer container images. By working together with
  inter-layer data deduplication and compression, we can achieve the
  next high-performance container image solution. Our team will announce
  the new Nydus container image service [3] implementation with new RAFS
  v6 (EROFS-compatible) format in Open Source Summit 2021 China [4]
  soon.

  Besides, the secondary compression head support and readmore
  decompression strategy are also included in this cycle. There are also
  some minor bugfixes and cleanups, as always.

  Summary:

   - support multiple devices for multi-layer container images;

   - support the secondary compression head;

   - support readmore decompression strategy;

   - support new LZMA algorithm (specifically called MicroLZMA);

   - some bugfixes & cleanups"

* tag 'erofs-for-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: don't trigger WARN() when decompression fails
  erofs: get rid of ->lru usage
  erofs: lzma compression support
  erofs: rename some generic methods in decompressor
  lib/xz, lib/decompress_unxz.c: Fix spelling in comments
  lib/xz: Add MicroLZMA decoder
  lib/xz: Move s->lzma.len = 0 initialization to lzma_reset()
  lib/xz: Validate the value before assigning it to an enum variable
  lib/xz: Avoid overlapping memcpy() with invalid input with in-place decompression
  erofs: introduce readmore decompression strategy
  erofs: introduce the secondary compression head
  erofs: get compression algorithms directly on mapping
  erofs: add multiple device support
  erofs: decouple basic mount options from fs_context
  erofs: remove the fast path of per-CPU buffer decompression

16 files changed, 959 insertions, 299 deletions

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 14b747026742..f57255ab88ed 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -6,16 +6,22 @@ config EROFS_FS
 	select FS_IOMAP
 	select LIBCRC32C
 	help
-	  EROFS (Enhanced Read-Only File System) is a lightweight
-	  read-only file system with modern designs (eg. page-sized
-	  blocks, inline xattrs/data, etc.) for scenarios which need
-	  high-performance read-only requirements, e.g. Android OS
-	  for mobile phones and LIVECDs.
+	  EROFS (Enhanced Read-Only File System) is a lightweight read-only
+	  file system with modern designs (e.g. no buffer heads, inline
+	  xattrs/data, chunk-based deduplication, multiple devices, etc.) for
+	  scenarios which need high-performance read-only solutions, e.g.
+	  smartphones with Android OS, LiveCDs and high-density hosts with
+	  numerous containers;
 
-	  It also provides fixed-sized output compression support,
-	  which improves storage density, keeps relatively higher
-	  compression ratios, which is more useful to achieve high
-	  performance for embedded devices with limited memory.
+	  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.
+
+	  See the documentation at <file:Documentation/filesystems/erofs.rst>
+	  for more details.
 
 	  If unsure, say N.
 
@@ -76,3 +82,19 @@ config EROFS_FS_ZIP
 	  Enable fixed-sized output compression for EROFS.
 
 	  If you don't want to enable compression feature, say N.
+
+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
+	  gives better compression ratios than the LZ4 algorithm, at the
+	  expense of more CPU overhead.
+
+	  LZMA support is an experimental feature for now and so most file
+	  systems will be readable without selecting this option.
+
+	  If unsure, say N.
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 1f9aced49070..756fe2d65272 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_EROFS_FS) += erofs.o
 erofs-objs := super.o inode.o data.o namei.o dir.o utils.o pcpubuf.o
 erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
 erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o
+erofs-$(CONFIG_EROFS_FS_ZIP_LZMA) += decompressor_lzma.o
diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
index 3701c72bacb2..579406504919 100644
--- a/fs/erofs/compress.h
+++ b/fs/erofs/compress.h
@@ -8,11 +8,6 @@
 
 #include "internal.h"
 
-enum {
-	Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
-	Z_EROFS_COMPRESSION_RUNTIME_MAX
-};
-
 struct z_erofs_decompress_req {
 	struct super_block *sb;
 	struct page **in, **out;
@@ -25,6 +20,12 @@ struct z_erofs_decompress_req {
 	bool inplace_io, partial_decoding;
 };
 
+struct z_erofs_decompressor {
+	int (*decompress)(struct z_erofs_decompress_req *rq,
+			  struct page **pagepool);
+	char *name;
+};
+
 /* some special page->private (unsigned long, see below) */
 #define Z_EROFS_SHORTLIVED_PAGE		(-1UL << 2)
 #define Z_EROFS_PREALLOCATED_PAGE	(-2UL << 2)
@@ -63,7 +64,7 @@ static inline bool z_erofs_is_shortlived_page(struct page *page)
 	return true;
 }
 
-static inline bool z_erofs_put_shortlivedpage(struct list_head *pagepool,
+static inline bool z_erofs_put_shortlivedpage(struct page **pagepool,
 					      struct page *page)
 {
 	if (!z_erofs_is_shortlived_page(page))
@@ -74,13 +75,22 @@ static inline bool z_erofs_put_shortlivedpage(struct list_head *pagepool,
 		put_page(page);
 	} else {
 		/* follow the pcluster rule above. */
-		set_page_private(page, 0);
-		list_add(&page->lru, pagepool);
+		erofs_pagepool_add(pagepool, page);
 	}
 	return true;
 }
 
+#define MNGD_MAPPING(sbi)	((sbi)->managed_cache->i_mapping)
+static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
+					 struct page *page)
+{
+	return page->mapping == MNGD_MAPPING(sbi);
+}
+
 int z_erofs_decompress(struct z_erofs_decompress_req *rq,
-		       struct list_head *pagepool);
+		       struct page **pagepool);
 
+/* prototypes for specific algorithms */
+int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
+			    struct page **pagepool);
 #endif
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 9db829715652..808234d9190c 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -89,6 +89,7 @@ static int erofs_map_blocks(struct inode *inode,
 	erofs_off_t pos;
 	int err = 0;
 
+	map->m_deviceid = 0;
 	if (map->m_la >= inode->i_size) {
 		/* leave out-of-bound access unmapped */
 		map->m_flags = 0;
@@ -135,14 +136,8 @@ static int erofs_map_blocks(struct inode *inode,
 		map->m_flags = 0;
 		break;
 	default:
-		/* only one device is supported for now */
-		if (idx->device_id) {
-			erofs_err(sb, "invalid device id %u @ %llu for nid %llu",
-				  le16_to_cpu(idx->device_id),
-				  chunknr, vi->nid);
-			err = -EFSCORRUPTED;
-			goto out_unlock;
-		}
+		map->m_deviceid = le16_to_cpu(idx->device_id) &
+			EROFS_SB(sb)->device_id_mask;
 		map->m_pa = blknr_to_addr(le32_to_cpu(idx->blkaddr));
 		map->m_flags = EROFS_MAP_MAPPED;
 		break;
@@ -155,11 +150,55 @@ out:
 	return err;
 }
 
+int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
+{
+	struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
+	struct erofs_device_info *dif;
+	int id;
+
+	/* primary device by default */
+	map->m_bdev = sb->s_bdev;
+	map->m_daxdev = EROFS_SB(sb)->dax_dev;
+
+	if (map->m_deviceid) {
+		down_read(&devs->rwsem);
+		dif = idr_find(&devs->tree, map->m_deviceid - 1);
+		if (!dif) {
+			up_read(&devs->rwsem);
+			return -ENODEV;
+		}
+		map->m_bdev = dif->bdev;
+		map->m_daxdev = dif->dax_dev;
+		up_read(&devs->rwsem);
+	} else if (devs->extra_devices) {
+		down_read(&devs->rwsem);
+		idr_for_each_entry(&devs->tree, dif, id) {
+			erofs_off_t startoff, length;
+
+			if (!dif->mapped_blkaddr)
+				continue;
+			startoff = blknr_to_addr(dif->mapped_blkaddr);
+			length = blknr_to_addr(dif->blocks);
+
+			if (map->m_pa >= startoff &&
+			    map->m_pa < startoff + length) {
+				map->m_pa -= startoff;
+				map->m_bdev = dif->bdev;
+				map->m_daxdev = dif->dax_dev;
+				break;
+			}
+		}
+		up_read(&devs->rwsem);
+	}
+	return 0;
+}
+
 static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 		unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
 {
 	int ret;
 	struct erofs_map_blocks map;
+	struct erofs_map_dev mdev;
 
 	map.m_la = offset;
 	map.m_llen = length;
@@ -168,8 +207,16 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	if (ret < 0)
 		return ret;
 
-	iomap->bdev = inode->i_sb->s_bdev;
-	iomap->dax_dev = EROFS_I_SB(inode)->dax_dev;
+	mdev = (struct erofs_map_dev) {
+		.m_deviceid = map.m_deviceid,
+		.m_pa = map.m_pa,
+	};
+	ret = erofs_map_dev(inode->i_sb, &mdev);
+	if (ret)
+		return ret;
+
+	iomap->bdev = mdev.m_bdev;
+	iomap->dax_dev = mdev.m_daxdev;
 	iomap->offset = map.m_la;
 	iomap->length = map.m_llen;
 	iomap->flags = 0;
@@ -188,15 +235,15 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 
 		iomap->type = IOMAP_INLINE;
 		ipage = erofs_get_meta_page(inode->i_sb,
-					    erofs_blknr(map.m_pa));
+					    erofs_blknr(mdev.m_pa));
 		if (IS_ERR(ipage))
 			return PTR_ERR(ipage);
 		iomap->inline_data = page_address(ipage) +
-					erofs_blkoff(map.m_pa);
+					erofs_blkoff(mdev.m_pa);
 		iomap->private = ipage;
 	} else {
 		iomap->type = IOMAP_MAPPED;
-		iomap->addr = map.m_pa;
+		iomap->addr = mdev.m_pa;
 	}
 	return 0;
 }
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index a5bc4b1b7813..bf37fc76b182 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -16,17 +16,6 @@
 #define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize)  (((srcsize) >> 8) + 32)
 #endif
 
-struct z_erofs_decompressor {
-	/*
-	 * if destpages have sparsed pages, fill them with bounce pages.
-	 * it also check whether destpages indicate continuous physical memory.
-	 */
-	int (*prepare_destpages)(struct z_erofs_decompress_req *rq,
-				 struct list_head *pagepool);
-	int (*decompress)(struct z_erofs_decompress_req *rq, u8 *out);
-	char *name;
-};
-
 int z_erofs_load_lz4_config(struct super_block *sb,
 			    struct erofs_super_block *dsb,
 			    struct z_erofs_lz4_cfgs *lz4, int size)
@@ -63,8 +52,12 @@ int z_erofs_load_lz4_config(struct super_block *sb,
 	return erofs_pcpubuf_growsize(sbi->lz4.max_pclusterblks);
 }
 
-static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
-					 struct list_head *pagepool)
+/*
+ * Fill all gaps with bounce pages if it's a sparse page list. Also check if
+ * all physical pages are consecutive, which can be seen for moderate CR.
+ */
+static int z_erofs_lz4_prepare_dstpages(struct z_erofs_decompress_req *rq,
+					struct page **pagepool)
 {
 	const unsigned int nr =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -119,7 +112,7 @@ static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
 	return kaddr ? 1 : 0;
 }
 
-static void *z_erofs_handle_inplace_io(struct z_erofs_decompress_req *rq,
+static void *z_erofs_lz4_handle_inplace_io(struct z_erofs_decompress_req *rq,
 			void *inpage, unsigned int *inputmargin, int *maptype,
 			bool support_0padding)
 {
@@ -189,7 +182,8 @@ docopy:
 	return src;
 }
 
-static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
+static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq,
+				      u8 *out)
 {
 	unsigned int inputmargin;
 	u8 *headpage, *src;
@@ -216,8 +210,8 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 	}
 
 	rq->inputsize -= inputmargin;
-	src = z_erofs_handle_inplace_io(rq, headpage, &inputmargin, &maptype,
-					support_0padding);
+	src = z_erofs_lz4_handle_inplace_io(rq, headpage, &inputmargin,
+					    &maptype, support_0padding);
 	if (IS_ERR(src))
 		return PTR_ERR(src);
 
@@ -233,7 +227,6 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 		erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]",
 			  ret, rq->inputsize, inputmargin, rq->outputsize);
 
-		WARN_ON(1);
 		print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
 			       16, 1, src + inputmargin, rq->inputsize, true);
 		print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET,
@@ -242,6 +235,8 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 		if (ret >= 0)
 			memset(out + ret, 0, rq->outputsize - ret);
 		ret = -EIO;
+	} else {
+		ret = 0;
 	}
 
 	if (maptype == 0) {
@@ -257,86 +252,25 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 	return ret;
 }
 
-static struct z_erofs_decompressor decompressors[] = {
-	[Z_EROFS_COMPRESSION_SHIFTED] = {
-		.name = "shifted"
-	},
-	[Z_EROFS_COMPRESSION_LZ4] = {
-		.prepare_destpages = z_erofs_lz4_prepare_destpages,
-		.decompress = z_erofs_lz4_decompress,
-		.name = "lz4"
-	},
-};
-
-static void copy_from_pcpubuf(struct page **out, const char *dst,
-			      unsigned short pageofs_out,
-			      unsigned int outputsize)
-{
-	const char *end = dst + outputsize;
-	const unsigned int righthalf = PAGE_SIZE - pageofs_out;
-	const char *cur = dst - pageofs_out;
-
-	while (cur < end) {
-		struct page *const page = *out++;
-
-		if (page) {
-			char *buf = kmap_atomic(page);
-
-			if (cur >= dst) {
-				memcpy(buf, cur, min_t(uint, PAGE_SIZE,
-						       end - cur));
-			} else {
-				memcpy(buf + pageofs_out, cur + pageofs_out,
-				       min_t(uint, righthalf, end - cur));
-			}
-			kunmap_atomic(buf);
-		}
-		cur += PAGE_SIZE;
-	}
-}
-
-static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
-				      struct list_head *pagepool)
+static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
+				  struct page **pagepool)
 {
 	const unsigned int nrpages_out =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
-	const struct z_erofs_decompressor *alg = decompressors + rq->alg;
 	unsigned int dst_maptype;
 	void *dst;
 	int ret;
 
-	/* two optimized fast paths only for non bigpcluster cases yet */
-	if (rq->inputsize <= PAGE_SIZE) {
-		if (nrpages_out == 1 && !rq->inplace_io) {
-			DBG_BUGON(!*rq->out);
-			dst = kmap_atomic(*rq->out);
-			dst_maptype = 0;
-			goto dstmap_out;
-		}
-
-		/*
-		 * For the case of small output size (especially much less
-		 * than PAGE_SIZE), memcpy the decompressed data rather than
-		 * compressed data is preferred.
-		 */
-		if (rq->outputsize <= PAGE_SIZE * 7 / 8) {
-			dst = erofs_get_pcpubuf(1);
-			if (IS_ERR(dst))
-				return PTR_ERR(dst);
-
-			rq->inplace_io = false;
-			ret = alg->decompress(rq, dst);
-			if (!ret)
-				copy_from_pcpubuf(rq->out, dst, rq->pageofs_out,
-						  rq->outputsize);
-
-			erofs_put_pcpubuf(dst);
-			return ret;
-		}
+	/* one optimized fast path only for non bigpcluster cases yet */
+	if (rq->inputsize <= PAGE_SIZE && nrpages_out == 1 && !rq->inplace_io) {
+		DBG_BUGON(!*rq->out);
+		dst = kmap_atomic(*rq->out);
+		dst_maptype = 0;
+		goto dstmap_out;
 	}
 
 	/* general decoding path which can be used for all cases */
-	ret = alg->prepare_destpages(rq, pagepool);
+	ret = z_erofs_lz4_prepare_dstpages(rq, pagepool);
 	if (ret < 0)
 		return ret;
 	if (ret) {
@@ -351,7 +285,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 	dst_maptype = 2;
 
 dstmap_out:
-	ret = alg->decompress(rq, dst + rq->pageofs_out);
+	ret = z_erofs_lz4_decompress_mem(rq, dst + rq->pageofs_out);
 
 	if (!dst_maptype)
 		kunmap_atomic(dst);
@@ -360,8 +294,8 @@ dstmap_out:
 	return ret;
 }
 
-static int z_erofs_shifted_transform(const struct z_erofs_decompress_req *rq,
-				     struct list_head *pagepool)
+static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
+				     struct page **pagepool)
 {
 	const unsigned int nrpages_out =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -399,10 +333,25 @@ static int z_erofs_shifted_transform(const struct z_erofs_decompress_req *rq,
 	return 0;
 }
 
+static struct z_erofs_decompressor decompressors[] = {
+	[Z_EROFS_COMPRESSION_SHIFTED] = {
+		.decompress = z_erofs_shifted_transform,
+		.name = "shifted"
+	},
+	[Z_EROFS_COMPRESSION_LZ4] = {
+		.decompress = z_erofs_lz4_decompress,
+		.name = "lz4"
+	},
+#ifdef CONFIG_EROFS_FS_ZIP_LZMA
+	[Z_EROFS_COMPRESSION_LZMA] = {
+		.decompress = z_erofs_lzma_decompress,
+		.name = "lzma"
+	},
+#endif
+};
+
 int z_erofs_decompress(struct z_erofs_decompress_req *rq,
-		       struct list_head *pagepool)
+		       struct page **pagepool)
 {
-	if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED)
-		return z_erofs_shifted_transform(rq, pagepool);
-	return z_erofs_decompress_generic(rq, pagepool);
+	return decompressors[rq->alg].decompress(rq, pagepool);
 }
diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
new file mode 100644
index 000000000000..50045510a1f4
--- /dev/null
+++ b/fs/erofs/decompressor_lzma.c
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/xz.h>
+#include <linux/module.h>
+#include "compress.h"
+
+struct z_erofs_lzma {
+	struct z_erofs_lzma *next;
+	struct xz_dec_microlzma *state;
+	struct xz_buf buf;
+	u8 bounce[PAGE_SIZE];
+};
+
+/* considering the LZMA performance, no need to use a lockless list for now */
+static DEFINE_SPINLOCK(z_erofs_lzma_lock);
+static unsigned int z_erofs_lzma_max_dictsize;
+static unsigned int z_erofs_lzma_nstrms, z_erofs_lzma_avail_strms;
+static struct z_erofs_lzma *z_erofs_lzma_head;
+static DECLARE_WAIT_QUEUE_HEAD(z_erofs_lzma_wq);
+
+module_param_named(lzma_streams, z_erofs_lzma_nstrms, uint, 0444);
+
+void z_erofs_lzma_exit(void)
+{
+	/* there should be no running fs instance */
+	while (z_erofs_lzma_avail_strms) {
+		struct z_erofs_lzma *strm;
+
+		spin_lock(&z_erofs_lzma_lock);
+		strm = z_erofs_lzma_head;
+		if (!strm) {
+			spin_unlock(&z_erofs_lzma_lock);
+			DBG_BUGON(1);
+			return;
+		}
+		z_erofs_lzma_head = NULL;
+		spin_unlock(&z_erofs_lzma_lock);
+
+		while (strm) {
+			struct z_erofs_lzma *n = strm->next;
+
+			if (strm->state)
+				xz_dec_microlzma_end(strm->state);
+			kfree(strm);
+			--z_erofs_lzma_avail_strms;
+			strm = n;
+		}
+	}
+}
+
+int z_erofs_lzma_init(void)
+{
+	unsigned int i;
+
+	/* by default, use # of possible CPUs instead */
+	if (!z_erofs_lzma_nstrms)
+		z_erofs_lzma_nstrms = num_possible_cpus();
+
+	for (i = 0; i < z_erofs_lzma_nstrms; ++i) {
+		struct z_erofs_lzma *strm = kzalloc(sizeof(*strm), GFP_KERNEL);
+
+		if (!strm) {
+			z_erofs_lzma_exit();
+			return -ENOMEM;
+		}
+		spin_lock(&z_erofs_lzma_lock);
+		strm->next = z_erofs_lzma_head;
+		z_erofs_lzma_head = strm;
+		spin_unlock(&z_erofs_lzma_lock);
+		++z_erofs_lzma_avail_strms;
+	}
+	return 0;
+}
+
+int z_erofs_load_lzma_config(struct super_block *sb,
+			     struct erofs_super_block *dsb,
+			     struct z_erofs_lzma_cfgs *lzma, int size)
+{
+	static DEFINE_MUTEX(lzma_resize_mutex);
+	unsigned int dict_size, i;
+	struct z_erofs_lzma *strm, *head = NULL;
+	int err;
+
+	if (!lzma || size < sizeof(struct z_erofs_lzma_cfgs)) {
+		erofs_err(sb, "invalid lzma cfgs, size=%u", size);
+		return -EINVAL;
+	}
+	if (lzma->format) {
+		erofs_err(sb, "unidentified lzma format %x, please check kernel version",
+			  le16_to_cpu(lzma->format));
+		return -EINVAL;
+	}
+	dict_size = le32_to_cpu(lzma->dict_size);
+	if (dict_size > Z_EROFS_LZMA_MAX_DICT_SIZE || dict_size < 4096) {
+		erofs_err(sb, "unsupported lzma dictionary size %u",
+			  dict_size);
+		return -EINVAL;
+	}
+
+	erofs_info(sb, "EXPERIMENTAL MicroLZMA in use. Use at your own risk!");
+
+	/* in case 2 z_erofs_load_lzma_config() race to avoid deadlock */
+	mutex_lock(&lzma_resize_mutex);
+
+	if (z_erofs_lzma_max_dictsize >= dict_size) {
+		mutex_unlock(&lzma_resize_mutex);
+		return 0;
+	}
+
+	/* 1. collect/isolate all streams for the following check */
+	for (i = 0; i < z_erofs_lzma_avail_strms; ++i) {
+		struct z_erofs_lzma *last;
+
+again:
+		spin_lock(&z_erofs_lzma_lock);
+		strm = z_erofs_lzma_head;
+		if (!strm) {
+			spin_unlock(&z_erofs_lzma_lock);
+			wait_event(z_erofs_lzma_wq,
+				   READ_ONCE(z_erofs_lzma_head));
+			goto again;
+		}
+		z_erofs_lzma_head = NULL;
+		spin_unlock(&z_erofs_lzma_lock);
+
+		for (last = strm; last->next; last = last->next)
+			++i;
+		last->next = head;
+		head = strm;
+	}
+
+	err = 0;
+	/* 2. walk each isolated stream and grow max dict_size if needed */
+	for (strm = head; strm; strm = strm->next) {
+		if (strm->state)
+			xz_dec_microlzma_end(strm->state);
+		strm->state = xz_dec_microlzma_alloc(XZ_PREALLOC, dict_size);
+		if (!strm->state)
+			err = -ENOMEM;
+	}
+
+	/* 3. push back all to the global list and update max dict_size */
+	spin_lock(&z_erofs_lzma_lock);
+	DBG_BUGON(z_erofs_lzma_head);
+	z_erofs_lzma_head = head;
+	spin_unlock(&z_erofs_lzma_lock);
+
+	z_erofs_lzma_max_dictsize = dict_size;
+	mutex_unlock(&lzma_resize_mutex);
+	return err;
+}
+
+int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
+			    struct page **pagepool)
+{
+	const unsigned int nrpages_out =
+		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
+	const unsigned int nrpages_in =
+		PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
+	unsigned int inputmargin, inlen, outlen, pageofs;
+	struct z_erofs_lzma *strm;
+	u8 *kin;
+	bool bounced = false;
+	int no, ni, j, err = 0;
+
+	/* 1. get the exact LZMA compressed size */
+	kin = kmap(*rq->in);
+	inputmargin = 0;
+	while (!kin[inputmargin & ~PAGE_MASK])
+		if (!(++inputmargin & ~PAGE_MASK))
+			break;
+
+	if (inputmargin >= PAGE_SIZE) {
+		kunmap(*rq->in);
+		return -EFSCORRUPTED;
+	}
+	rq->inputsize -= inputmargin;
+
+	/* 2. get an available lzma context */
+again:
+	spin_lock(&z_erofs_lzma_lock);
+	strm = z_erofs_lzma_head;
+	if (!strm) {
+		spin_unlock(&z_erofs_lzma_lock);
+		wait_event(z_erofs_lzma_wq, READ_ONCE(z_erofs_lzma_head));
+		goto again;
+	}
+	z_erofs_lzma_head = strm->next;
+	spin_unlock(&z_erofs_lzma_lock);
+
+	/* 3. multi-call decompress */
+	inlen = rq->inputsize;
+	outlen = rq->outputsize;
+	xz_dec_microlzma_reset(strm->state, inlen, outlen,
+			       !rq->partial_decoding);
+	pageofs = rq->pageofs_out;
+	strm->buf.in = kin + inputmargin;
+	strm->buf.in_pos = 0;
+	strm->buf.in_size = min_t(u32, inlen, PAGE_SIZE - inputmargin);
+	inlen -= strm->buf.in_size;
+	strm->buf.out = NULL;
+	strm->buf.out_pos = 0;
+	strm->buf.out_size = 0;
+
+	for (ni = 0, no = -1;;) {
+		enum xz_ret xz_err;
+
+		if (strm->buf.out_pos == strm->buf.out_size) {
+			if (strm->buf.out) {
+				kunmap(rq->out[no]);
+				strm->buf.out = NULL;
+			}
+
+			if (++no >= nrpages_out || !outlen) {
+				erofs_err(rq->sb, "decompressed buf out of bound");
+				err = -EFSCORRUPTED;
+				break;
+			}
+			strm->buf.out_pos = 0;
+			strm->buf.out_size = min_t(u32, outlen,
+						   PAGE_SIZE - pageofs);
+			outlen -= strm->buf.out_size;
+			if (rq->out[no])
+				strm->buf.out = kmap(rq->out[no]) + pageofs;
+			pageofs = 0;
+		} else if (strm->buf.in_pos == strm->buf.in_size) {
+			kunmap(rq->in[ni]);
+
+			if (++ni >= nrpages_in || !inlen) {
+				erofs_err(rq->sb, "compressed buf out of bound");
+				err = -EFSCORRUPTED;
+				break;
+			}
+			strm->buf.in_pos = 0;
+			strm->buf.in_size = min_t(u32, inlen, PAGE_SIZE);
+			inlen -= strm->buf.in_size;
+			kin = kmap(rq->in[ni]);
+			strm->buf.in = kin;
+			bounced = false;
+		}
+
+		/*
+		 * Handle overlapping: Use bounced buffer if the compressed
+		 * data is under processing; Otherwise, Use short-lived pages
+		 * from the on-stack pagepool where pages share with the same
+		 * request.
+		 */
+		if (!bounced && rq->out[no] == rq->in[ni]) {
+			memcpy(strm->bounce, strm->buf.in, strm->buf.in_size);
+			strm->buf.in = strm->bounce;
+			bounced = true;
+		}
+		for (j = ni + 1; j < nrpages_in; ++j) {
+			struct page *tmppage;
+
+			if (rq->out[no] != rq->in[j])
+				continue;
+
+			DBG_BUGON(erofs_page_is_managed(EROFS_SB(rq->sb),
+							rq->in[j]));
+			tmppage = erofs_allocpage(pagepool,
+						  GFP_KERNEL | __GFP_NOFAIL);
+			set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE);
+			copy_highpage(tmppage, rq->in[j]);
+			rq->in[j] = tmppage;
+		}
+		xz_err = xz_dec_microlzma_run(strm->state, &strm->buf);
+		DBG_BUGON(strm->buf.out_pos > strm->buf.out_size);
+		DBG_BUGON(strm->buf.in_pos > strm->buf.in_size);
+
+		if (xz_err != XZ_OK) {
+			if (xz_err == XZ_STREAM_END && !outlen)
+				break;
+			erofs_err(rq->sb, "failed to decompress %d in[%u] out[%u]",
+				  xz_err, rq->inputsize, rq->outputsize);
+			err = -EFSCORRUPTED;
+			break;
+		}
+	}
+	if (no < nrpages_out && strm->buf.out)
+		kunmap(rq->in[no]);
+	if (ni < nrpages_in)
+		kunmap(rq->in[ni]);
+	/* 4. push back LZMA stream context to the global list */
+	spin_lock(&z_erofs_lzma_lock);
+	strm->next = z_erofs_lzma_head;
+	z_erofs_lzma_head = strm;
+	spin_unlock(&z_erofs_lzma_lock);
+	wake_up(&z_erofs_lzma_wq);
+	return err;
+}
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index b0b23f41abc3..083997a034e5 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -21,14 +21,29 @@
 #define EROFS_FEATURE_INCOMPAT_COMPR_CFGS	0x00000002
 #define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER	0x00000002
 #define EROFS_FEATURE_INCOMPAT_CHUNKED_FILE	0x00000004
+#define EROFS_FEATURE_INCOMPAT_DEVICE_TABLE	0x00000008
+#define EROFS_FEATURE_INCOMPAT_COMPR_HEAD2	0x00000008
 #define EROFS_ALL_FEATURE_INCOMPAT		\
 	(EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | \
 	 EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
 	 EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER | \
-	 EROFS_FEATURE_INCOMPAT_CHUNKED_FILE)
+	 EROFS_FEATURE_INCOMPAT_CHUNKED_FILE | \
+	 EROFS_FEATURE_INCOMPAT_DEVICE_TABLE | \
+	 EROFS_FEATURE_INCOMPAT_COMPR_HEAD2)
 
 #define EROFS_SB_EXTSLOT_SIZE	16
 
+struct erofs_deviceslot {
+	union {
+		u8 uuid[16];		/* used for device manager later */
+		u8 userdata[64];	/* digest(sha256), etc. */
+	} u;
+	__le32 blocks;			/* total fs blocks of this device */
+	__le32 mapped_blkaddr;		/* map starting at mapped_blkaddr */
+	u8 reserved[56];
+};
+#define EROFS_DEVT_SLOT_SIZE	sizeof(struct erofs_deviceslot)
+
 /* erofs on-disk super block (currently 128 bytes) */
 struct erofs_super_block {
 	__le32 magic;           /* file system magic number */
@@ -54,7 +69,9 @@ struct erofs_super_block {
 		/* customized sliding window size instead of 64k by default */
 		__le16 lz4_max_distance;
 	} __packed u1;
-	__u8 reserved2[42];
+	__le16 extra_devices;	/* # of devices besides the primary device */
+	__le16 devt_slotoff;	/* startoff = devt_slotoff * devt_slotsize */
+	__u8 reserved2[38];
 };
 
 /*
@@ -238,7 +255,7 @@ static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)
 /* 8-byte inode chunk indexes */
 struct erofs_inode_chunk_index {
 	__le16 advise;		/* always 0, don't care for now */
-	__le16 device_id;	/* back-end storage id, always 0 for now */
+	__le16 device_id;	/* back-end storage id (with bits masked) */
 	__le32 blkaddr;		/* start block address of this inode chunk */
 };
 
@@ -247,10 +264,11 @@ struct erofs_inode_chunk_index {
 
 /* available compression algorithm types (for h_algorithmtype) */
 enum {
-	Z_EROFS_COMPRESSION_LZ4	= 0,
+	Z_EROFS_COMPRESSION_LZ4		= 0,
+	Z_EROFS_COMPRESSION_LZMA	= 1,
 	Z_EROFS_COMPRESSION_MAX
 };
-#define Z_EROFS_ALL_COMPR_ALGS		(1 << (Z_EROFS_COMPRESSION_MAX - 1))
+#define Z_EROFS_ALL_COMPR_ALGS		((1 << Z_EROFS_COMPRESSION_MAX) - 1)
 
 /* 14 bytes (+ length field = 16 bytes) */
 struct z_erofs_lz4_cfgs {
@@ -259,6 +277,15 @@ struct z_erofs_lz4_cfgs {
 	u8 reserved[10];
 } __packed;
 
+/* 14 bytes (+ length field = 16 bytes) */
+struct z_erofs_lzma_cfgs {
+	__le32 dict_size;
+	__le16 format;
+	u8 reserved[8];
+} __packed;
+
+#define Z_EROFS_LZMA_MAX_DICT_SIZE	(8 * Z_EROFS_PCLUSTER_MAX_SIZE)
+
 /*
  * bit 0 : COMPACTED_2B indexes (0 - off; 1 - on)
  *  e.g. for 4k logical cluster size,      4B        if compacted 2B is off;
@@ -288,35 +315,34 @@ struct z_erofs_map_header {
 #define Z_EROFS_VLE_LEGACY_HEADER_PADDING       8
 
 /*
- * Fixed-sized output compression ondisk Logical Extent cluster type:
- *    0 - literal (uncompressed) cluster
- *    1 - compressed cluster (for the head logical cluster)
- *    2 - compressed cluster (for the other logical clusters)
+ * Fixed-sized output compression on-disk logical cluster type:
+ *    0   - literal (uncompressed) lcluster
+ *    1,3 - compressed lcluster (for HEAD lclusters)
+ *    2   - compressed lcluster (for NONHEAD lclusters)
  *
  * In detail,
- *    0 - literal (uncompressed) cluster,
+ *    0 - literal (uncompressed) lcluster,
  *        di_advise = 0
- *        di_clusterofs = the literal data offset of the cluster
- *        di_blkaddr = the blkaddr of the literal cluster
+ *        di_clusterofs = the literal data offset of the lcluster
+ *        di_blkaddr = the blkaddr of the literal pcluster
  *
- *    1 - compressed cluster (for the head logical cluster)
- *        di_advise = 1
- *        di_clusterofs = the decompressed data offset of the cluster
- *        di_blkaddr = the blkaddr of the compressed cluster
+ *    1,3 - compressed lcluster (for HEAD lclusters)
+ *        di_advise = 1 or 3
+ *        di_clusterofs = the decompressed data offset of the lcluster
+ *        di_blkaddr = the blkaddr of the compressed pcluster
  *
- *    2 - compressed cluster (for the other logical clusters)
+ *    2 - compressed lcluster (for NONHEAD lclusters)
  *        di_advise = 2
  *        di_clusterofs =
- *           the decompressed data offset in its own head cluster
- *        di_u.delta[0] = distance to its corresponding head cluster
- *        di_u.delta[1] = distance to its corresponding tail cluster
- *                (di_advise could be 0, 1 or 2)
+ *           the decompressed data offset in its own HEAD lcluster
+ *        di_u.delta[0] = distance to this HEAD lcluster
+ *        di_u.delta[1] = distance to the next HEAD lcluster
  */
 enum {
 	Z_EROFS_VLE_CLUSTER_TYPE_PLAIN		= 0,
-	Z_EROFS_VLE_CLUSTER_TYPE_HEAD		= 1,
+	Z_EROFS_VLE_CLUSTER_TYPE_HEAD1		= 1,
 	Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD	= 2,
-	Z_EROFS_VLE_CLUSTER_TYPE_RESERVED	= 3,
+	Z_EROFS_VLE_CLUSTER_TYPE_HEAD2		= 3,
 	Z_EROFS_VLE_CLUSTER_TYPE_MAX
 };
 
@@ -384,6 +410,7 @@ static inline void erofs_check_ondisk_layout_definitions(void)
 	/* keep in sync between 2 index structures for better extendibility */
 	BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) !=
 		     sizeof(struct z_erofs_vle_decompressed_index));
+	BUILD_BUG_ON(sizeof(struct erofs_deviceslot) != 128);
 
 	BUILD_BUG_ON(BIT(Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) <
 		     Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1);
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index a552399e211d..2345f1de438e 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -192,7 +192,7 @@ static struct page *erofs_read_inode(struct inode *inode,
 	inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec;
 
 	inode->i_flags &= ~S_DAX;
-	if (test_opt(&sbi->ctx, DAX_ALWAYS) && S_ISREG(inode->i_mode) &&
+	if (test_opt(&sbi->opt, DAX_ALWAYS) && S_ISREG(inode->i_mode) &&
 	    vi->datalayout == EROFS_INODE_FLAT_PLAIN)
 		inode->i_flags |= S_DAX;
 	if (!nblks)
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 9524e155b38f..3265688af7f9 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -47,7 +47,16 @@ typedef u64 erofs_off_t;
 /* data type for filesystem-wide blocks number */
 typedef u32 erofs_blk_t;
 
-struct erofs_fs_context {
+struct erofs_device_info {
+	char *path;
+	struct block_device *bdev;
+	struct dax_device *dax_dev;
+
+	u32 blocks;
+	u32 mapped_blkaddr;
+};
+
+struct erofs_mount_opts {
 #ifdef CONFIG_EROFS_FS_ZIP
 	/* current strategy of how to use managed cache */
 	unsigned char cache_strategy;
@@ -60,6 +69,18 @@ struct erofs_fs_context {
 	unsigned int mount_opt;
 };
 
+struct erofs_dev_context {
+	struct idr tree;
+	struct rw_semaphore rwsem;
+
+	unsigned int extra_devices;
+};
+
+struct erofs_fs_context {
+	struct erofs_mount_opts opt;
+	struct erofs_dev_context *devs;
+};
+
 /* all filesystem-wide lz4 configurations */
 struct erofs_sb_lz4_info {
 	/* # of pages needed for EROFS lz4 rolling decompression */
@@ -69,6 +90,7 @@ struct erofs_sb_lz4_info {
 };
 
 struct erofs_sb_info {
+	struct erofs_mount_opts opt;	/* options */
 #ifdef CONFIG_EROFS_FS_ZIP
 	/* list for all registered superblocks, mainly for shrinker */
 	struct list_head list;
@@ -85,12 +107,16 @@ struct erofs_sb_info {
 
 	struct erofs_sb_lz4_info lz4;
 #endif	/* CONFIG_EROFS_FS_ZIP */
+	struct erofs_dev_context *devs;
 	struct dax_device *dax_dev;
-	u32 blocks;
+	u64 total_blocks;
+	u32 primarydevice_blocks;
+
 	u32 meta_blkaddr;
 #ifdef CONFIG_EROFS_FS_XATTR
 	u32 xattr_blkaddr;
 #endif
+	u16 device_id_mask;	/* valid bits of device id to be used */
 
 	/* inode slot unit size in bit shift */
 	unsigned char islotbits;
@@ -108,8 +134,6 @@ struct erofs_sb_info {
 	u8 volume_name[16];             /* volume name */
 	u32 feature_compat;
 	u32 feature_incompat;
-
-	struct erofs_fs_context ctx;	/* options */
 };
 
 #define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
@@ -121,9 +145,9 @@ struct erofs_sb_info {
 #define EROFS_MOUNT_DAX_ALWAYS		0x00000040
 #define EROFS_MOUNT_DAX_NEVER		0x00000080
 
-#define clear_opt(ctx, option)	((ctx)->mount_opt &= ~EROFS_MOUNT_##option)
-#define set_opt(ctx, option)	((ctx)->mount_opt |= EROFS_MOUNT_##option)
-#define test_opt(ctx, option)	((ctx)->mount_opt & EROFS_MOUNT_##option)
+#define clear_opt(opt, option)	((opt)->mount_opt &= ~EROFS_MOUNT_##option)
+#define set_opt(opt, option)	((opt)->mount_opt |= EROFS_MOUNT_##option)
+#define test_opt(opt, option)	((opt)->mount_opt & EROFS_MOUNT_##option)
 
 enum {
 	EROFS_ZIP_CACHE_DISABLED,
@@ -237,6 +261,7 @@ static inline bool erofs_sb_has_##name(struct erofs_sb_info *sbi) \
 EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)
 EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
 EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
+EROFS_FEATURE_FUNCS(device_table, incompat, INCOMPAT_DEVICE_TABLE)
 EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
 
 /* atomic flag definitions */
@@ -307,6 +332,19 @@ static inline unsigned int erofs_inode_datalayout(unsigned int value)
 			      EROFS_I_DATALAYOUT_BITS);
 }
 
+/*
+ * Different from grab_cache_page_nowait(), reclaiming is never triggered
+ * when allocating new pages.
+ */
+static inline
+struct page *erofs_grab_cache_page_nowait(struct address_space *mapping,
+					  pgoff_t index)
+{
+	return pagecache_get_page(mapping, index,
+			FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
+			readahead_gfp_mask(mapping) & ~__GFP_RECLAIM);
+}
+
 extern const struct super_operations erofs_sops;
 
 extern const struct address_space_operations erofs_raw_access_aops;
@@ -338,7 +376,7 @@ extern const struct address_space_operations z_erofs_aops;
  * of the corresponding uncompressed data in the file.
  */
 enum {
-	BH_Zipped = BH_PrivateStart,
+	BH_Encoded = BH_PrivateStart,
 	BH_FullMapped,
 };
 
@@ -346,8 +384,8 @@ enum {
 #define EROFS_MAP_MAPPED	(1 << BH_Mapped)
 /* Located in metadata (could be copied from bd_inode) */
 #define EROFS_MAP_META		(1 << BH_Meta)
-/* The extent has been compressed */
-#define EROFS_MAP_ZIPPED	(1 << BH_Zipped)
+/* The extent is encoded */
+#define EROFS_MAP_ENCODED	(1 << BH_Encoded)
 /* The length of extent is full */
 #define EROFS_MAP_FULL_MAPPED	(1 << BH_FullMapped)
 
@@ -355,6 +393,8 @@ struct erofs_map_blocks {
 	erofs_off_t m_pa, m_la;
 	u64 m_plen, m_llen;
 
+	unsigned short m_deviceid;
+	char m_algorithmformat;
 	unsigned int m_flags;
 
 	struct page *mpage;
@@ -367,6 +407,13 @@ struct erofs_map_blocks {
  * approach instead if possible since it's more metadata lightweight.)
  */
 #define EROFS_GET_BLOCKS_FIEMAP	0x0002
+/* Used to map the whole extent if non-negligible data is requested for LZMA */
+#define EROFS_GET_BLOCKS_READMORE	0x0004
+
+enum {
+	Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+	Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
 
 /* zmap.c */
 extern const struct iomap_ops z_erofs_iomap_report_ops;
@@ -386,9 +433,18 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
 }
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
+struct erofs_map_dev {
+	struct block_device *m_bdev;
+	struct dax_device *m_daxdev;
+
+	erofs_off_t m_pa;
+	unsigned int m_deviceid;
+};
+
 /* data.c */
 extern const struct file_operations erofs_file_fops;
 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
+int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *dev);
 int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		 u64 start, u64 len);
 
@@ -443,7 +499,14 @@ void erofs_pcpubuf_init(void);
 void erofs_pcpubuf_exit(void);
 
 /* utils.c / zdata.c */
-struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp);
+struct page *erofs_allocpage(struct page **pagepool, gfp_t gfp);
+static inline void erofs_pagepool_add(struct page **pagepool,
+		struct page *page)
+{
+	set_page_private(page, (unsigned long)*pagepool);
+	*pagepool = page;
+}
+void erofs_release_pages(struct page **pagepool);
 
 #ifdef CONFIG_EROFS_FS_ZIP
 int erofs_workgroup_put(struct erofs_workgroup *grp);
@@ -483,6 +546,26 @@ static inline int z_erofs_load_lz4_config(struct super_block *sb,
 }
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
+#ifdef CONFIG_EROFS_FS_ZIP_LZMA
+int z_erofs_lzma_init(void);
+void z_erofs_lzma_exit(void);
+int z_erofs_load_lzma_config(struct super_block *sb,
+			     struct erofs_super_block *dsb,
+			     struct z_erofs_lzma_cfgs *lzma, int size);
+#else
+static inline int z_erofs_lzma_init(void) { return 0; }
+static inline int z_erofs_lzma_exit(void) { return 0; }
+static inline int z_erofs_load_lzma_config(struct super_block *sb,
+			     struct erofs_super_block *dsb,
+			     struct z_erofs_lzma_cfgs *lzma, int size) {
+	if (lzma) {
+		erofs_err(sb, "lzma algorithm isn't enabled");
+		return -EINVAL;
+	}
+	return 0;
+}
+#endif	/* !CONFIG_EROFS_FS_ZIP */
+
 #define EFSCORRUPTED    EUCLEAN         /* Filesystem is corrupted */
 
 #endif	/* __EROFS_INTERNAL_H */
diff --git a/fs/erofs/pcpubuf.c b/fs/erofs/pcpubuf.c
index 6c885575128a..a2efd833d1b6 100644
--- a/fs/erofs/pcpubuf.c
+++ b/fs/erofs/pcpubuf.c
@@ -49,7 +49,7 @@ int erofs_pcpubuf_growsize(unsigned int nrpages)
 {
 	static DEFINE_MUTEX(pcb_resize_mutex);
 	static unsigned int pcb_nrpages;
-	LIST_HEAD(pagepool);
+	struct page *pagepool = NULL;
 	int delta, cpu, ret, i;
 
 	mutex_lock(&pcb_resize_mutex);
@@ -102,13 +102,13 @@ int erofs_pcpubuf_growsize(unsigned int nrpages)
 			vunmap(old_ptr);
 free_pagearray:
 		while (i)
-			list_add(&oldpages[--i]->lru, &pagepool);
+			erofs_pagepool_add(&pagepool, oldpages[--i]);
 		kfree(oldpages);
 		if (ret)
 			break;
 	}
 	pcb_nrpages = nrpages;
-	put_pages_list(&pagepool);
+	erofs_release_pages(&pagepool);
 out:
 	mutex_unlock(&pcb_resize_mutex);
 	return ret;
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 11b88559f8bf..6a969b1e0ee6 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -225,6 +225,9 @@ static int erofs_load_compr_cfgs(struct super_block *sb,
 		case Z_EROFS_COMPRESSION_LZ4:
 			ret = z_erofs_load_lz4_config(sb, dsb, data, size);
 			break;
+		case Z_EROFS_COMPRESSION_LZMA:
+			ret = z_erofs_load_lzma_config(sb, dsb, data, size);
+			break;
 		default:
 			DBG_BUGON(1);
 			ret = -EFAULT;
@@ -252,6 +255,79 @@ static int erofs_load_compr_cfgs(struct super_block *sb,
 }
 #endif
 
+static int erofs_init_devices(struct super_block *sb,
+			      struct erofs_super_block *dsb)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	unsigned int ondisk_extradevs;
+	erofs_off_t pos;
+	struct page *page = NULL;
+	struct erofs_device_info *dif;
+	struct erofs_deviceslot *dis;
+	void *ptr;
+	int id, err = 0;
+
+	sbi->total_blocks = sbi->primarydevice_blocks;
+	if (!erofs_sb_has_device_table(sbi))
+		ondisk_extradevs = 0;
+	else
+		ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
+
+	if (ondisk_extradevs != sbi->devs->extra_devices) {
+		erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
+			  ondisk_extradevs, sbi->devs->extra_devices);
+		return -EINVAL;
+	}
+	if (!ondisk_extradevs)
+		return 0;
+
+	sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
+	pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
+	down_read(&sbi->devs->rwsem);
+	idr_for_each_entry(&sbi->devs->tree, dif, id) {
+		erofs_blk_t blk = erofs_blknr(pos);
+		struct block_device *bdev;
+
+		if (!page || page->index != blk) {
+			if (page) {
+				kunmap(page);
+				unlock_page(page);
+				put_page(page);
+			}
+
+			page = erofs_get_meta_page(sb, blk);
+			if (IS_ERR(page)) {
+				up_read(&sbi->devs->rwsem);
+				return PTR_ERR(page);
+			}
+			ptr = kmap(page);
+		}
+		dis = ptr + erofs_blkoff(pos);
+
+		bdev = blkdev_get_by_path(dif->path,
+					  FMODE_READ | FMODE_EXCL,
+					  sb->s_type);
+		if (IS_ERR(bdev)) {
+			err = PTR_ERR(bdev);
+			goto err_out;
+		}
+		dif->bdev = bdev;
+		dif->dax_dev = fs_dax_get_by_bdev(bdev);
+		dif->blocks = le32_to_cpu(dis->blocks);
+		dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
+		sbi->total_blocks += dif->blocks;
+		pos += EROFS_DEVT_SLOT_SIZE;
+	}
+err_out:
+	up_read(&sbi->devs->rwsem);
+	if (page) {
+		kunmap(page);
+		unlock_page(page);
+		put_page(page);
+	}
+	return err;
+}
+
 static int erofs_read_superblock(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi;
@@ -303,7 +379,7 @@ static int erofs_read_superblock(struct super_block *sb)
 			  sbi->sb_size);
 		goto out;
 	}
-	sbi->blocks = le32_to_cpu(dsb->blocks);
+	sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
 	sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
 #ifdef CONFIG_EROFS_FS_XATTR
 	sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
@@ -330,6 +406,11 @@ static int erofs_read_superblock(struct super_block *sb)
 		ret = erofs_load_compr_cfgs(sb, dsb);
 	else
 		ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	if (ret < 0)
+		goto out;
+
+	/* handle multiple devices */
+	ret = erofs_init_devices(sb, dsb);
 out:
 	kunmap(page);
 	put_page(page);
@@ -340,15 +421,15 @@ out:
 static void erofs_default_options(struct erofs_fs_context *ctx)
 {
 #ifdef CONFIG_EROFS_FS_ZIP
-	ctx->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
-	ctx->max_sync_decompress_pages = 3;
-	ctx->readahead_sync_decompress = false;
+	ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
+	ctx->opt.max_sync_decompress_pages = 3;
+	ctx->opt.readahead_sync_decompress = false;
 #endif
 #ifdef CONFIG_EROFS_FS_XATTR
-	set_opt(ctx, XATTR_USER);
+	set_opt(&ctx->opt, XATTR_USER);
 #endif
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
-	set_opt(ctx, POSIX_ACL);
+	set_opt(&ctx->opt, POSIX_ACL);
 #endif
 }
 
@@ -358,6 +439,7 @@ enum {
 	Opt_cache_strategy,
 	Opt_dax,
 	Opt_dax_enum,
+	Opt_device,
 	Opt_err
 };
 
@@ -381,6 +463,7 @@ static const struct fs_parameter_spec erofs_fs_parameters[] = {
 		     erofs_param_cache_strategy),
 	fsparam_flag("dax",             Opt_dax),
 	fsparam_enum("dax",		Opt_dax_enum, erofs_dax_param_enums),
+	fsparam_string("device",	Opt_device),
 	{}
 };
 
@@ -392,12 +475,12 @@ static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
 	switch (mode) {
 	case EROFS_MOUNT_DAX_ALWAYS:
 		warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
-		set_opt(ctx, DAX_ALWAYS);
-		clear_opt(ctx, DAX_NEVER);
+		set_opt(&ctx->opt, DAX_ALWAYS);
+		clear_opt(&ctx->opt, DAX_NEVER);
 		return true;
 	case EROFS_MOUNT_DAX_NEVER:
-		set_opt(ctx, DAX_NEVER);
-		clear_opt(ctx, DAX_ALWAYS);
+		set_opt(&ctx->opt, DAX_NEVER);
+		clear_opt(&ctx->opt, DAX_ALWAYS);
 		return true;
 	default:
 		DBG_BUGON(1);
@@ -412,9 +495,10 @@ static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
 static int erofs_fc_parse_param(struct fs_context *fc,
 				struct fs_parameter *param)
 {
-	struct erofs_fs_context *ctx __maybe_unused = fc->fs_private;
+	struct erofs_fs_context *ctx = fc->fs_private;
 	struct fs_parse_result result;
-	int opt;
+	struct erofs_device_info *dif;
+	int opt, ret;
 
 	opt = fs_parse(fc, erofs_fs_parameters, param, &result);
 	if (opt < 0)
@@ -424,9 +508,9 @@ static int erofs_fc_parse_param(struct fs_context *fc,
 	case Opt_user_xattr:
 #ifdef CONFIG_EROFS_FS_XATTR
 		if (result.boolean)
-			set_opt(ctx, XATTR_USER);
+			set_opt(&ctx->opt, XATTR_USER);
 		else
-			clear_opt(ctx, XATTR_USER);
+			clear_opt(&ctx->opt, XATTR_USER);
 #else
 		errorfc(fc, "{,no}user_xattr options not supported");
 #endif
@@ -434,16 +518,16 @@ static int erofs_fc_parse_param(struct fs_context *fc,
 	case Opt_acl:
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
 		if (result.boolean)
-			set_opt(ctx, POSIX_ACL);
+			set_opt(&ctx->opt, POSIX_ACL);
 		else
-			clear_opt(ctx, POSIX_ACL);
+			clear_opt(&ctx->opt, POSIX_ACL);
 #else
 		errorfc(fc, "{,no}acl options not supported");
 #endif
 		break;
 	case Opt_cache_strategy:
 #ifdef CONFIG_EROFS_FS_ZIP
-		ctx->cache_strategy = result.uint_32;
+		ctx->opt.cache_strategy = result.uint_32;
 #else
 		errorfc(fc, "compression not supported, cache_strategy ignored");
 #endif
@@ -456,6 +540,25 @@ static int erofs_fc_parse_param(struct fs_context *fc,
 		if (!erofs_fc_set_dax_mode(fc, result.uint_32))
 			return -EINVAL;
 		break;
+	case Opt_device:
+		dif = kzalloc(sizeof(*dif), GFP_KERNEL);
+		if (!dif)
+			return -ENOMEM;
+		dif->path = kstrdup(param->string, GFP_KERNEL);
+		if (!dif->path) {
+			kfree(dif);
+			return -ENOMEM;
+		}
+		down_write(&ctx->devs->rwsem);
+		ret = idr_alloc(&ctx->devs->tree, dif, 0, 0, GFP_KERNEL);
+		up_write(&ctx->devs->rwsem);
+		if (ret < 0) {
+			kfree(dif->path);
+			kfree(dif);
+			return ret;
+		}
+		++ctx->devs->extra_devices;
+		break;
 	default:
 		return -ENOPARAM;
 	}
@@ -540,15 +643,19 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 		return -ENOMEM;
 
 	sb->s_fs_info = sbi;
+	sbi->opt = ctx->opt;
 	sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
+	sbi->devs = ctx->devs;
+	ctx->devs = NULL;
+
 	err = erofs_read_superblock(sb);
 	if (err)
 		return err;
 
-	if (test_opt(ctx, DAX_ALWAYS) &&
+	if (test_opt(&sbi->opt, DAX_ALWAYS) &&
 	    !dax_supported(sbi->dax_dev, sb->s_bdev, EROFS_BLKSIZ, 0, bdev_nr_sectors(sb->s_bdev))) {
 		errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
-		clear_opt(ctx, DAX_ALWAYS);
+		clear_opt(&sbi->opt, DAX_ALWAYS);
 	}
 	sb->s_flags |= SB_RDONLY | SB_NOATIME;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
@@ -557,13 +664,11 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_op = &erofs_sops;
 	sb->s_xattr = erofs_xattr_handlers;
 
-	if (test_opt(ctx, POSIX_ACL))
+	if (test_opt(&sbi->opt, POSIX_ACL))
 		sb->s_flags |= SB_POSIXACL;
 	else
 		sb->s_flags &= ~SB_POSIXACL;
 
-	sbi->ctx = *ctx;
-
 #ifdef CONFIG_EROFS_FS_ZIP
 	xa_init(&sbi->managed_pslots);
 #endif
@@ -607,20 +712,44 @@ static int erofs_fc_reconfigure(struct fs_context *fc)
 
 	DBG_BUGON(!sb_rdonly(sb));
 
-	if (test_opt(ctx, POSIX_ACL))
+	if (test_opt(&ctx->opt, POSIX_ACL))
 		fc->sb_flags |= SB_POSIXACL;
 	else
 		fc->sb_flags &= ~SB_POSIXACL;
 
-	sbi->ctx = *ctx;
+	sbi->opt = ctx->opt;
 
 	fc->sb_flags |= SB_RDONLY;
 	return 0;
 }
 
+static int erofs_release_device_info(int id, void *ptr, void *data)
+{
+	struct erofs_device_info *dif = ptr;
+
+	fs_put_dax(dif->dax_dev);
+	if (dif->bdev)
+		blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL);
+	kfree(dif->path);
+	kfree(dif);
+	return 0;
+}
+
+static void erofs_free_dev_context(struct erofs_dev_context *devs)
+{
+	if (!devs)
+		return;
+	idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
+	idr_destroy(&devs->tree);
+	kfree(devs);
+}
+
 static void erofs_fc_free(struct fs_context *fc)
 {
-	kfree(fc->fs_private);
+	struct erofs_fs_context *ctx = fc->fs_private;
+
+	erofs_free_dev_context(ctx->devs);
+	kfree(ctx);
 }
 
 static const struct fs_context_operations erofs_context_ops = {
@@ -632,15 +761,21 @@ static const struct fs_context_operations erofs_context_ops = {
 
 static int erofs_init_fs_context(struct fs_context *fc)
 {
-	fc->fs_private = kzalloc(sizeof(struct erofs_fs_context), GFP_KERNEL);
-	if (!fc->fs_private)
-		return -ENOMEM;
+	struct erofs_fs_context *ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 
-	/* set default mount options */
-	erofs_default_options(fc->fs_private);
+	if (!ctx)
+		return -ENOMEM;
+	ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
+	if (!ctx->devs) {
+		kfree(ctx);
+		return -ENOMEM;
+	}
+	fc->fs_private = ctx;
 
+	idr_init(&ctx->devs->tree);
+	init_rwsem(&ctx->devs->rwsem);
+	erofs_default_options(ctx);
 	fc->ops = &erofs_context_ops;
-
 	return 0;
 }
 
@@ -659,6 +794,8 @@ static void erofs_kill_sb(struct super_block *sb)
 	sbi = EROFS_SB(sb);
 	if (!sbi)
 		return;
+
+	erofs_free_dev_context(sbi->devs);
 	fs_put_dax(sbi->dax_dev);
 	kfree(sbi);
 	sb->s_fs_info = NULL;
@@ -706,6 +843,10 @@ static int __init erofs_module_init(void)
 	if (err)
 		goto shrinker_err;
 
+	err = z_erofs_lzma_init();
+	if (err)
+		goto lzma_err;
+
 	erofs_pcpubuf_init();
 	err = z_erofs_init_zip_subsystem();
 	if (err)
@@ -720,6 +861,8 @@ static int __init erofs_module_init(void)
 fs_err:
 	z_erofs_exit_zip_subsystem();
 zip_err:
+	z_erofs_lzma_exit();
+lzma_err:
 	erofs_exit_shrinker();
 shrinker_err:
 	kmem_cache_destroy(erofs_inode_cachep);
@@ -730,11 +873,13 @@ icache_err:
 static void __exit erofs_module_exit(void)
 {
 	unregister_filesystem(&erofs_fs_type);
-	z_erofs_exit_zip_subsystem();
-	erofs_exit_shrinker();
 
-	/* Ensure all RCU free inodes are safe before cache is destroyed. */
+	/* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
 	rcu_barrier();
+
+	z_erofs_exit_zip_subsystem();
+	z_erofs_lzma_exit();
+	erofs_exit_shrinker();
 	kmem_cache_destroy(erofs_inode_cachep);
 	erofs_pcpubuf_exit();
 }
@@ -748,7 +893,7 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 
 	buf->f_type = sb->s_magic;
 	buf->f_bsize = EROFS_BLKSIZ;
-	buf->f_blocks = sbi->blocks;
+	buf->f_blocks = sbi->total_blocks;
 	buf->f_bfree = buf->f_bavail = 0;
 
 	buf->f_files = ULLONG_MAX;
@@ -763,31 +908,31 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
-	struct erofs_fs_context *ctx = &sbi->ctx;
+	struct erofs_mount_opts *opt = &sbi->opt;
 
 #ifdef CONFIG_EROFS_FS_XATTR
-	if (test_opt(ctx, XATTR_USER))
+	if (test_opt(opt, XATTR_USER))
 		seq_puts(seq, ",user_xattr");
 	else
 		seq_puts(seq, ",nouser_xattr");
 #endif
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
-	if (test_opt(ctx, POSIX_ACL))
+	if (test_opt(opt, POSIX_ACL))
 		seq_puts(seq, ",acl");
 	else
 		seq_puts(seq, ",noacl");
 #endif
 #ifdef CONFIG_EROFS_FS_ZIP
-	if (ctx->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
+	if (opt->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
 		seq_puts(seq, ",cache_strategy=disabled");
-	else if (ctx->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
+	else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
 		seq_puts(seq, ",cache_strategy=readahead");
-	else if (ctx->cache_strategy == EROFS_ZIP_CACHE_READAROUND)
+	else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAROUND)
 		seq_puts(seq, ",cache_strategy=readaround");
 #endif
-	if (test_opt(ctx, DAX_ALWAYS))
+	if (test_opt(opt, DAX_ALWAYS))
 		seq_puts(seq, ",dax=always");
-	if (test_opt(ctx, DAX_NEVER))
+	if (test_opt(opt, DAX_NEVER))
 		seq_puts(seq, ",dax=never");
 	return 0;
 }
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index bd86067a63f7..84da2c280012 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -6,20 +6,29 @@
 #include "internal.h"
 #include <linux/pagevec.h>
 
-struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp)
+struct page *erofs_allocpage(struct page **pagepool, gfp_t gfp)
 {
-	struct page *page;
+	struct page *page = *pagepool;
 
-	if (!list_empty(pool)) {
-		page = lru_to_page(pool);
+	if (page) {
 		DBG_BUGON(page_ref_count(page) != 1);
-		list_del(&page->lru);
+		*pagepool = (struct page *)page_private(page);
 	} else {
 		page = alloc_page(gfp);
 	}
 	return page;
 }
 
+void erofs_release_pages(struct page **pagepool)
+{
+	while (*pagepool) {
+		struct page *page = *pagepool;
+
+		*pagepool = (struct page *)page_private(page);
+		put_page(page);
+	}
+}
+
 #ifdef CONFIG_EROFS_FS_ZIP
 /* global shrink count (for all mounted EROFS instances) */
 static atomic_long_t erofs_global_shrink_cnt;
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 778f2c52295d..01c581e93c5f 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -429,7 +429,7 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
 
 static bool erofs_xattr_user_list(struct dentry *dentry)
 {
-	return test_opt(&EROFS_SB(dentry->d_sb)->ctx, XATTR_USER);
+	return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER);
 }
 
 static bool erofs_xattr_trusted_list(struct dentry *dentry)
@@ -476,7 +476,7 @@ static int erofs_xattr_generic_get(const struct xattr_handler *handler,
 
 	switch (handler->flags) {
 	case EROFS_XATTR_INDEX_USER:
-		if (!test_opt(&sbi->ctx, XATTR_USER))
+		if (!test_opt(&sbi->opt, XATTR_USER))
 			return -EOPNOTSUPP;
 		break;
 	case EROFS_XATTR_INDEX_TRUSTED:
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 11c7a1aaebad..bcb1b91b234f 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -236,7 +236,7 @@ static DEFINE_MUTEX(z_pagemap_global_lock);
 static void preload_compressed_pages(struct z_erofs_collector *clt,
 				     struct address_space *mc,
 				     enum z_erofs_cache_alloctype type,
-				     struct list_head *pagepool)
+				     struct page **pagepool)
 {
 	struct z_erofs_pcluster *pcl = clt->pcl;
 	bool standalone = true;
@@ -287,12 +287,10 @@ static void preload_compressed_pages(struct z_erofs_collector *clt,
 		if (!cmpxchg_relaxed(pages, NULL, tagptr_cast_ptr(t)))
 			continue;
 
-		if (page) {
+		if (page)
 			put_page(page);
-		} else if (newpage) {
-			set_page_private(newpage, 0);
-			list_add(&newpage->lru, pagepool);
-		}
+		else if (newpage)
+			erofs_pagepool_add(pagepool, newpage);
 	}
 
 	/*
@@ -476,6 +474,11 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
 	struct erofs_workgroup *grp;
 	int err;
 
+	if (!(map->m_flags & EROFS_MAP_ENCODED)) {
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+
 	/* no available pcluster, let's allocate one */
 	pcl = z_erofs_alloc_pcluster(map->m_plen >> PAGE_SHIFT);
 	if (IS_ERR(pcl))
@@ -483,16 +486,11 @@ static int z_erofs_register_collection(struct z_erofs_collector *clt,
 
 	atomic_set(&pcl->obj.refcount, 1);
 	pcl->obj.index = map->m_pa >> PAGE_SHIFT;
-
+	pcl->algorithmformat = map->m_algorithmformat;
 	pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) |
 		(map->m_flags & EROFS_MAP_FULL_MAPPED ?
 			Z_EROFS_PCLUSTER_FULL_LENGTH : 0);
 
-	if (map->m_flags & EROFS_MAP_ZIPPED)
-		pcl->algorithmformat = Z_EROFS_COMPRESSION_LZ4;
-	else
-		pcl->algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
-
 	/* new pclusters should be claimed as type 1, primary and followed */
 	pcl->next = clt->owned_head;
 	clt->mode = COLLECT_PRIMARY_FOLLOWED;
@@ -643,7 +641,7 @@ static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe,
 }
 
 static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
-				struct page *page, struct list_head *pagepool)
+				struct page *page, struct page **pagepool)
 {
 	struct inode *const inode = fe->inode;
 	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
@@ -695,7 +693,7 @@ restart_now:
 		goto err_out;
 
 	/* preload all compressed pages (maybe downgrade role if necessary) */
-	if (should_alloc_managed_pages(fe, sbi->ctx.cache_strategy, map->m_la))
+	if (should_alloc_managed_pages(fe, sbi->opt.cache_strategy, map->m_la))
 		cache_strategy = TRYALLOC;
 	else
 		cache_strategy = DONTALLOC;
@@ -796,7 +794,7 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
 	/* Use workqueue and sync decompression for atomic contexts only */
 	if (in_atomic() || irqs_disabled()) {
 		queue_work(z_erofs_workqueue, &io->u.work);
-		sbi->ctx.readahead_sync_decompress = true;
+		sbi->opt.readahead_sync_decompress = true;
 		return;
 	}
 	z_erofs_decompressqueue_work(&io->u.work);
@@ -836,7 +834,7 @@ static void z_erofs_decompressqueue_endio(struct bio *bio)
 
 static int z_erofs_decompress_pcluster(struct super_block *sb,
 				       struct z_erofs_pcluster *pcl,
-				       struct list_head *pagepool)
+				       struct page **pagepool)
 {
 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
 	struct z_erofs_pagevec_ctor ctor;
@@ -1036,7 +1034,7 @@ out:
 }
 
 static void z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
-				     struct list_head *pagepool)
+				     struct page **pagepool)
 {
 	z_erofs_next_pcluster_t owned = io->head;
 
@@ -1060,18 +1058,18 @@ static void z_erofs_decompressqueue_work(struct work_struct *work)
 {
 	struct z_erofs_decompressqueue *bgq =
 		container_of(work, struct z_erofs_decompressqueue, u.work);
-	LIST_HEAD(pagepool);
+	struct page *pagepool = NULL;
 
 	DBG_BUGON(bgq->head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
 	z_erofs_decompress_queue(bgq, &pagepool);
 
-	put_pages_list(&pagepool);
+	erofs_release_pages(&pagepool);
 	kvfree(bgq);
 }
 
 static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
 					       unsigned int nr,
-					       struct list_head *pagepool,
+					       struct page **pagepool,
 					       struct address_space *mc,
 					       gfp_t gfp)
 {
@@ -1173,7 +1171,7 @@ repeat:
 out_allocpage:
 	page = erofs_allocpage(pagepool, gfp | __GFP_NOFAIL);
 	if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) {
-		list_add(&page->lru, pagepool);
+		erofs_pagepool_add(pagepool, page);
 		cond_resched();
 		goto repeat;
 	}
@@ -1257,7 +1255,7 @@ static void move_to_bypass_jobqueue(struct z_erofs_pcluster *pcl,
 
 static void z_erofs_submit_queue(struct super_block *sb,
 				 struct z_erofs_decompress_frontend *f,
-				 struct list_head *pagepool,
+				 struct page **pagepool,
 				 struct z_erofs_decompressqueue *fgq,
 				 bool *force_fg)
 {
@@ -1266,8 +1264,9 @@ static void z_erofs_submit_queue(struct super_block *sb,
 	struct z_erofs_decompressqueue *q[NR_JOBQUEUES];
 	void *bi_private;
 	z_erofs_next_pcluster_t owned_head = f->clt.owned_head;
-	/* since bio will be NULL, no need to initialize last_index */
+	/* bio is NULL initially, so no need to initialize last_{index,bdev} */
 	pgoff_t last_index;
+	struct block_device *last_bdev;
 	unsigned int nr_bios = 0;
 	struct bio *bio = NULL;
 
@@ -1279,6 +1278,7 @@ static void z_erofs_submit_queue(struct super_block *sb,
 	q[JQ_SUBMIT]->head = owned_head;
 
 	do {
+		struct erofs_map_dev mdev;
 		struct z_erofs_pcluster *pcl;
 		pgoff_t cur, end;
 		unsigned int i = 0;
@@ -1290,7 +1290,13 @@ static void z_erofs_submit_queue(struct super_block *sb,
 
 		pcl = container_of(owned_head, struct z_erofs_pcluster, next);
 
-		cur = pcl->obj.index;
+		/* no device id here, thus it will always succeed */
+		mdev = (struct erofs_map_dev) {
+			.m_pa = blknr_to_addr(pcl->obj.index),
+		};
+		(void)erofs_map_dev(sb, &mdev);
+
+		cur = erofs_blknr(mdev.m_pa);
 		end = cur + pcl->pclusterpages;
 
 		/* close the main owned chain at first */
@@ -1306,7 +1312,8 @@ static void z_erofs_submit_queue(struct super_block *sb,
 			if (!page)
 				continue;
 
-			if (bio && cur != last_index + 1) {
+			if (bio && (cur != last_index + 1 ||
+				    last_bdev != mdev.m_bdev)) {
 submit_bio_retry:
 				submit_bio(bio);
 				bio = NULL;
@@ -1314,9 +1321,10 @@ submit_bio_retry:
 
 			if (!bio) {
 				bio = bio_alloc(GFP_NOIO, BIO_MAX_VECS);
-
 				bio->bi_end_io = z_erofs_decompressqueue_endio;
-				bio_set_dev(bio, sb->s_bdev);
+
+				bio_set_dev(bio, mdev.m_bdev);
+				last_bdev = mdev.m_bdev;
 				bio->bi_iter.bi_sector = (sector_t)cur <<
 					LOG_SECTORS_PER_BLOCK;
 				bio->bi_private = bi_private;
@@ -1355,7 +1363,7 @@ submit_bio_retry:
 
 static void z_erofs_runqueue(struct super_block *sb,
 			     struct z_erofs_decompress_frontend *f,
-			     struct list_head *pagepool, bool force_fg)
+			     struct page **pagepool, bool force_fg)
 {
 	struct z_erofs_decompressqueue io[NR_JOBQUEUES];
 
@@ -1377,18 +1385,87 @@ static void z_erofs_runqueue(struct super_block *sb,
 	z_erofs_decompress_queue(&io[JQ_SUBMIT], pagepool);
 }
 
+/*
+ * Since partial uptodate is still unimplemented for now, we have to use
+ * approximate readmore strategies as a start.
+ */
+static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
+				      struct readahead_control *rac,
+				      erofs_off_t end,
+				      struct page **pagepool,
+				      bool backmost)
+{
+	struct inode *inode = f->inode;
+	struct erofs_map_blocks *map = &f->map;
+	erofs_off_t cur;
+	int err;
+
+	if (backmost) {
+		map->m_la = end;
+		err = z_erofs_map_blocks_iter(inode, map,
+					      EROFS_GET_BLOCKS_READMORE);
+		if (err)
+			return;
+
+		/* expend ra for the trailing edge if readahead */
+		if (rac) {
+			loff_t newstart = readahead_pos(rac);
+
+			cur = round_up(map->m_la + map->m_llen, PAGE_SIZE);
+			readahead_expand(rac, newstart, cur - newstart);
+			return;
+		}
+		end = round_up(end, PAGE_SIZE);
+	} else {
+		end = round_up(map->m_la, PAGE_SIZE);
+
+		if (!map->m_llen)
+			return;
+	}
+
+	cur = map->m_la + map->m_llen - 1;
+	while (cur >= end) {
+		pgoff_t index = cur >> PAGE_SHIFT;
+		struct page *page;
+
+		page = erofs_grab_cache_page_nowait(inode->i_mapping, index);
+		if (!page)
+			goto skip;
+
+		if (PageUptodate(page)) {
+			unlock_page(page);
+			put_page(page);
+			goto skip;
+		}
+
+		err = z_erofs_do_read_page(f, page, pagepool);
+		if (err)
+			erofs_err(inode->i_sb,
+				  "readmore error at page %lu @ nid %llu",
+				  index, EROFS_I(inode)->nid);
+		put_page(page);
+skip:
+		if (cur < PAGE_SIZE)
+			break;
+		cur = (index << PAGE_SHIFT) - 1;
+	}
+}
+
 static int z_erofs_readpage(struct file *file, struct page *page)
 {
 	struct inode *const inode = page->mapping->host;
 	struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
+	struct page *pagepool = NULL;
 	int err;
-	LIST_HEAD(pagepool);
 
 	trace_erofs_readpage(page, false);
-
 	f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT;
 
+	z_erofs_pcluster_readmore(&f, NULL, f.headoffset + PAGE_SIZE - 1,
+				  &pagepool, true);
 	err = z_erofs_do_read_page(&f, page, &pagepool);
+	z_erofs_pcluster_readmore(&f, NULL, 0, &pagepool, false);
+
 	(void)z_erofs_collector_end(&f.clt);
 
 	/* if some compressed cluster ready, need submit them anyway */
@@ -1400,8 +1477,7 @@ static int z_erofs_readpage(struct file *file, struct page *page)
 	if (f.map.mpage)
 		put_page(f.map.mpage);
 
-	/* clean up the remaining free pages */
-	put_pages_list(&pagepool);
+	erofs_release_pages(&pagepool);
 	return err;
 }
 
@@ -1409,29 +1485,19 @@ static void z_erofs_readahead(struct readahead_control *rac)
 {
 	struct inode *const inode = rac->mapping->host;
 	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
-
-	unsigned int nr_pages = readahead_count(rac);
-	bool sync = (sbi->ctx.readahead_sync_decompress &&
-			nr_pages <= sbi->ctx.max_sync_decompress_pages);
 	struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
-	struct page *page, *head = NULL;
-	LIST_HEAD(pagepool);
-
-	trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false);
+	struct page *pagepool = NULL, *head = NULL, *page;
+	unsigned int nr_pages;
 
 	f.readahead = true;
 	f.headoffset = readahead_pos(rac);
 
-	while ((page = readahead_page(rac))) {
-		prefetchw(&page->flags);
-
-		/*
-		 * A pure asynchronous readahead is indicated if
-		 * a PG_readahead marked page is hitted at first.
-		 * Let's also do asynchronous decompression for this case.
-		 */
-		sync &= !(PageReadahead(page) && !head);
+	z_erofs_pcluster_readmore(&f, rac, f.headoffset +
+				  readahead_length(rac) - 1, &pagepool, true);
+	nr_pages = readahead_count(rac);
+	trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false);
 
+	while ((page = readahead_page(rac))) {
 		set_page_private(page, (unsigned long)head);
 		head = page;
 	}
@@ -1450,16 +1516,15 @@ static void z_erofs_readahead(struct readahead_control *rac)
 				  page->index, EROFS_I(inode)->nid);
 		put_page(page);
 	}
-
+	z_erofs_pcluster_readmore(&f, rac, 0, &pagepool, false);
 	(void)z_erofs_collector_end(&f.clt);
 
-	z_erofs_runqueue(inode->i_sb, &f, &pagepool, sync);
-
+	z_erofs_runqueue(inode->i_sb, &f, &pagepool,
+			 sbi->opt.readahead_sync_decompress &&
+			 nr_pages <= sbi->opt.max_sync_decompress_pages);
 	if (f.map.mpage)
 		put_page(f.map.mpage);
-
-	/* clean up the remaining free pages */
-	put_pages_list(&pagepool);
+	erofs_release_pages(&pagepool);
 }
 
 const struct address_space_operations z_erofs_aops = {
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index 3a008f1b9f78..879df5362777 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -94,13 +94,6 @@ struct z_erofs_decompressqueue {
 	} u;
 };
 
-#define MNGD_MAPPING(sbi)	((sbi)->managed_cache->i_mapping)
-static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
-					 struct page *page)
-{
-	return page->mapping == MNGD_MAPPING(sbi);
-}
-
 #define Z_EROFS_ONLINEPAGE_COUNT_BITS   2
 #define Z_EROFS_ONLINEPAGE_COUNT_MASK   ((1 << Z_EROFS_ONLINEPAGE_COUNT_BITS) - 1)
 #define Z_EROFS_ONLINEPAGE_INDEX_SHIFT  (Z_EROFS_ONLINEPAGE_COUNT_BITS)
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 7a6df35fdc91..660489a7fb64 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -28,7 +28,7 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 {
 	struct erofs_inode *const vi = EROFS_I(inode);
 	struct super_block *const sb = inode->i_sb;
-	int err;
+	int err, headnr;
 	erofs_off_t pos;
 	struct page *page;
 	void *kaddr;
@@ -68,9 +68,11 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 	vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
 	vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
 
-	if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) {
-		erofs_err(sb, "unknown compression format %u for nid %llu, please upgrade kernel",
-			  vi->z_algorithmtype[0], vi->nid);
+	headnr = 0;
+	if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX ||
+	    vi->z_algorithmtype[++headnr] >= Z_EROFS_COMPRESSION_MAX) {
+		erofs_err(sb, "unknown HEAD%u format %u for nid %llu, please upgrade kernel",
+			  headnr + 1, vi->z_algorithmtype[headnr], vi->nid);
 		err = -EOPNOTSUPP;
 		goto unmap_done;
 	}
@@ -111,7 +113,7 @@ struct z_erofs_maprecorder {
 
 	unsigned long lcn;
 	/* compression extent information gathered */
-	u8  type;
+	u8  type, headtype;
 	u16 clusterofs;
 	u16 delta[2];
 	erofs_blk_t pblk, compressedlcs;
@@ -178,7 +180,8 @@ static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 		m->clusterofs = 1 << vi->z_logical_clusterbits;
 		m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
 		if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
-			if (!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+			if (!(vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
+					Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
 				DBG_BUGON(1);
 				return -EFSCORRUPTED;
 			}
@@ -189,7 +192,8 @@ static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 		m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
 		break;
 	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
-	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
 		m->clusterofs = le16_to_cpu(di->di_clusterofs);
 		m->pblk = le32_to_cpu(di->di_u.blkaddr);
 		break;
@@ -446,9 +450,9 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
 		}
 		return z_erofs_extent_lookback(m, m->delta[0]);
 	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
-		map->m_flags &= ~EROFS_MAP_ZIPPED;
-		fallthrough;
-	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
+		m->headtype = m->type;
 		map->m_la = (lcn << lclusterbits) | m->clusterofs;
 		break;
 	default:
@@ -471,13 +475,18 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 	int err;
 
 	DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
-		  m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD);
-	if (!(map->m_flags & EROFS_MAP_ZIPPED) ||
-	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+		  m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD1 &&
+		  m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD2);
+	DBG_BUGON(m->type != m->headtype);
+
+	if (m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN ||
+	    ((m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD1) &&
+	     !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) ||
+	    ((m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2) &&
+	     !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
 		map->m_plen = 1 << lclusterbits;
 		return 0;
 	}
-
 	lcn = m->lcn + 1;
 	if (m->compressedlcs)
 		goto out;
@@ -499,7 +508,8 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 
 	switch (m->type) {
 	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
-	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
 		/*
 		 * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
 		 * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
@@ -554,7 +564,8 @@ static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
 			DBG_BUGON(!m->delta[1] &&
 				  m->clusterofs != 1 << lclusterbits);
 		} else if (m->type == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN ||
-			   m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD) {
+			   m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD1 ||
+			   m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2) {
 			/* go on until the next HEAD lcluster */
 			if (lcn != headlcn)
 				break;
@@ -609,16 +620,15 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 	if (err)
 		goto unmap_out;
 
-	map->m_flags = EROFS_MAP_ZIPPED;	/* by default, compressed */
+	map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_ENCODED;
 	end = (m.lcn + 1ULL) << lclusterbits;
 
 	switch (m.type) {
 	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
-		if (endoff >= m.clusterofs)
-			map->m_flags &= ~EROFS_MAP_ZIPPED;
-		fallthrough;
-	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
 		if (endoff >= m.clusterofs) {
+			m.headtype = m.type;
 			map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
 			break;
 		}
@@ -650,13 +660,22 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 
 	map->m_llen = end - map->m_la;
 	map->m_pa = blknr_to_addr(m.pblk);
-	map->m_flags |= EROFS_MAP_MAPPED;
 
 	err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
 	if (err)
 		goto out;
 
-	if (flags & EROFS_GET_BLOCKS_FIEMAP) {
+	if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN)
+		map->m_algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
+	else if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2)
+		map->m_algorithmformat = vi->z_algorithmtype[1];
+	else
+		map->m_algorithmformat = vi->z_algorithmtype[0];
+
+	if ((flags & EROFS_GET_BLOCKS_FIEMAP) ||
+	    ((flags & EROFS_GET_BLOCKS_READMORE) &&
+	     map->m_algorithmformat == Z_EROFS_COMPRESSION_LZMA &&
+	     map->m_llen >= EROFS_BLKSIZ)) {
 		err = z_erofs_get_extent_decompressedlen(&m);
 		if (!err)
 			map->m_flags |= EROFS_MAP_FULL_MAPPED;