Adding upstream version 6.7.7.upstream/6.7.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

14 files changed, 104 insertions, 141 deletions

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index f6dc961e6c..1d318f8523 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -21,7 +21,7 @@ config EROFS_FS
 	  performance under extremely memory pressure without extra cost.
 
 	  See the documentation at <file:Documentation/filesystems/erofs.rst>
-	  for more details.
+	  and the web pages at <https://erofs.docs.kernel.org> for more details.
 
 	  If unsure, say N.
 
@@ -91,13 +91,10 @@ config EROFS_FS_ZIP_LZMA
 	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
+	  containing LZMA compressed data, specifically called microLZMA. It
+	  gives better compression ratios than the default LZ4 format, 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.
 
 config EROFS_FS_ZIP_DEFLATE
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 0c2c99c58b..c98aeda8ab 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -5,9 +5,7 @@
  * Copyright (C) 2021, Alibaba Cloud
  */
 #include "internal.h"
-#include <linux/prefetch.h>
 #include <linux/sched/mm.h>
-#include <linux/dax.h>
 #include <trace/events/erofs.h>
 
 void erofs_unmap_metabuf(struct erofs_buf *buf)
@@ -222,7 +220,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			up_read(&devs->rwsem);
 			return 0;
 		}
-		map->m_bdev = dif->bdev;
+		map->m_bdev = dif->bdev_handle ? dif->bdev_handle->bdev : NULL;
 		map->m_daxdev = dif->dax_dev;
 		map->m_dax_part_off = dif->dax_part_off;
 		map->m_fscache = dif->fscache;
@@ -240,7 +238,8 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			if (map->m_pa >= startoff &&
 			    map->m_pa < startoff + length) {
 				map->m_pa -= startoff;
-				map->m_bdev = dif->bdev;
+				map->m_bdev = dif->bdev_handle ?
+					      dif->bdev_handle->bdev : NULL;
 				map->m_daxdev = dif->dax_dev;
 				map->m_dax_part_off = dif->dax_part_off;
 				map->m_fscache = dif->fscache;
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index d36b3963c0..066ddc03b7 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -4,7 +4,6 @@
  *             https://www.huawei.com/
  */
 #include "compress.h"
-#include <linux/module.h>
 #include <linux/lz4.h>
 
 #ifndef LZ4_DISTANCE_MAX	/* history window size */
diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c
index 0e1946a6bd..daf3c1bdea 100644
--- a/fs/erofs/decompressor_deflate.c
+++ b/fs/erofs/decompressor_deflate.c
@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
-#include <linux/module.h>
 #include <linux/zlib.h>
 #include "compress.h"
 
diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index ba4ec73f4a..2dd14f99c1 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -1,6 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 #include <linux/xz.h>
-#include <linux/module.h>
 #include "compress.h"
 
 struct z_erofs_lzma {
@@ -96,8 +95,6 @@ int z_erofs_load_lzma_config(struct super_block *sb,
 		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);
 
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index edc8ec7581..14a79d3226 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -15,11 +15,11 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	struct erofs_inode *vi = EROFS_I(inode);
 	const erofs_off_t inode_loc = erofs_iloc(inode);
-
 	erofs_blk_t blkaddr, nblks = 0;
 	void *kaddr;
 	struct erofs_inode_compact *dic;
 	struct erofs_inode_extended *die, *copied = NULL;
+	union erofs_inode_i_u iu;
 	unsigned int ifmt;
 	int err;
 
@@ -35,9 +35,8 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 
 	dic = kaddr + *ofs;
 	ifmt = le16_to_cpu(dic->i_format);
-
 	if (ifmt & ~EROFS_I_ALL) {
-		erofs_err(inode->i_sb, "unsupported i_format %u of nid %llu",
+		erofs_err(sb, "unsupported i_format %u of nid %llu",
 			  ifmt, vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
@@ -45,7 +44,7 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 
 	vi->datalayout = erofs_inode_datalayout(ifmt);
 	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
-		erofs_err(inode->i_sb, "unsupported datalayout %u of nid %llu",
+		erofs_err(sb, "unsupported datalayout %u of nid %llu",
 			  vi->datalayout, vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
@@ -82,40 +81,15 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(die->i_mode);
-		switch (inode->i_mode & S_IFMT) {
-		case S_IFREG:
-		case S_IFDIR:
-		case S_IFLNK:
-			vi->raw_blkaddr = le32_to_cpu(die->i_u.raw_blkaddr);
-			break;
-		case S_IFCHR:
-		case S_IFBLK:
-			inode->i_rdev =
-				new_decode_dev(le32_to_cpu(die->i_u.rdev));
-			break;
-		case S_IFIFO:
-		case S_IFSOCK:
-			inode->i_rdev = 0;
-			break;
-		default:
-			goto bogusimode;
-		}
+		iu = die->i_u;
 		i_uid_write(inode, le32_to_cpu(die->i_uid));
 		i_gid_write(inode, le32_to_cpu(die->i_gid));
 		set_nlink(inode, le32_to_cpu(die->i_nlink));
-
-		/* extended inode has its own timestamp */
+		/* each extended inode has its own timestamp */
 		inode_set_ctime(inode, le64_to_cpu(die->i_mtime),
 				le32_to_cpu(die->i_mtime_nsec));
 
 		inode->i_size = le64_to_cpu(die->i_size);
-
-		/* total blocks for compressed files */
-		if (erofs_inode_is_data_compressed(vi->datalayout))
-			nblks = le32_to_cpu(die->i_u.compressed_blocks);
-		else if (vi->datalayout == EROFS_INODE_CHUNK_BASED)
-			/* fill chunked inode summary info */
-			vi->chunkformat = le16_to_cpu(die->i_u.c.format);
 		kfree(copied);
 		copied = NULL;
 		break;
@@ -125,49 +99,51 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		vi->xattr_isize = erofs_xattr_ibody_size(dic->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(dic->i_mode);
-		switch (inode->i_mode & S_IFMT) {
-		case S_IFREG:
-		case S_IFDIR:
-		case S_IFLNK:
-			vi->raw_blkaddr = le32_to_cpu(dic->i_u.raw_blkaddr);
-			break;
-		case S_IFCHR:
-		case S_IFBLK:
-			inode->i_rdev =
-				new_decode_dev(le32_to_cpu(dic->i_u.rdev));
-			break;
-		case S_IFIFO:
-		case S_IFSOCK:
-			inode->i_rdev = 0;
-			break;
-		default:
-			goto bogusimode;
-		}
+		iu = dic->i_u;
 		i_uid_write(inode, le16_to_cpu(dic->i_uid));
 		i_gid_write(inode, le16_to_cpu(dic->i_gid));
 		set_nlink(inode, le16_to_cpu(dic->i_nlink));
-
 		/* use build time for compact inodes */
 		inode_set_ctime(inode, sbi->build_time, sbi->build_time_nsec);
 
 		inode->i_size = le32_to_cpu(dic->i_size);
-		if (erofs_inode_is_data_compressed(vi->datalayout))
-			nblks = le32_to_cpu(dic->i_u.compressed_blocks);
-		else if (vi->datalayout == EROFS_INODE_CHUNK_BASED)
-			vi->chunkformat = le16_to_cpu(dic->i_u.c.format);
 		break;
 	default:
-		erofs_err(inode->i_sb,
-			  "unsupported on-disk inode version %u of nid %llu",
+		erofs_err(sb, "unsupported on-disk inode version %u of nid %llu",
 			  erofs_inode_version(ifmt), vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
 	}
 
-	if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+	case S_IFDIR:
+	case S_IFLNK:
+		vi->raw_blkaddr = le32_to_cpu(iu.raw_blkaddr);
+		break;
+	case S_IFCHR:
+	case S_IFBLK:
+		inode->i_rdev = new_decode_dev(le32_to_cpu(iu.rdev));
+		break;
+	case S_IFIFO:
+	case S_IFSOCK:
+		inode->i_rdev = 0;
+		break;
+	default:
+		erofs_err(sb, "bogus i_mode (%o) @ nid %llu", inode->i_mode,
+			  vi->nid);
+		err = -EFSCORRUPTED;
+		goto err_out;
+	}
+
+	/* total blocks for compressed files */
+	if (erofs_inode_is_data_compressed(vi->datalayout)) {
+		nblks = le32_to_cpu(iu.compressed_blocks);
+	} else if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
+		/* fill chunked inode summary info */
+		vi->chunkformat = le16_to_cpu(iu.c.format);
 		if (vi->chunkformat & ~EROFS_CHUNK_FORMAT_ALL) {
-			erofs_err(inode->i_sb,
-				  "unsupported chunk format %x of nid %llu",
+			erofs_err(sb, "unsupported chunk format %x of nid %llu",
 				  vi->chunkformat, vi->nid);
 			err = -EOPNOTSUPP;
 			goto err_out;
@@ -175,7 +151,8 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		vi->chunkbits = sb->s_blocksize_bits +
 			(vi->chunkformat & EROFS_CHUNK_FORMAT_BLKBITS_MASK);
 	}
-	inode->i_mtime = inode->i_atime = inode_get_ctime(inode);
+	inode_set_mtime_to_ts(inode,
+			      inode_set_atime_to_ts(inode, inode_get_ctime(inode)));
 
 	inode->i_flags &= ~S_DAX;
 	if (test_opt(&sbi->opt, DAX_ALWAYS) && S_ISREG(inode->i_mode) &&
@@ -190,10 +167,6 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		inode->i_blocks = nblks << (sb->s_blocksize_bits - 9);
 	return kaddr;
 
-bogusimode:
-	erofs_err(inode->i_sb, "bogus i_mode (%o) @ nid %llu",
-		  inode->i_mode, vi->nid);
-	err = -EFSCORRUPTED;
 err_out:
 	DBG_BUGON(1);
 	kfree(copied);
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index d8de61350d..b0409badb0 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -8,8 +8,10 @@
 #define __EROFS_INTERNAL_H
 
 #include <linux/fs.h>
+#include <linux/dax.h>
 #include <linux/dcache.h>
 #include <linux/mm.h>
+#include <linux/module.h>
 #include <linux/pagemap.h>
 #include <linux/bio.h>
 #include <linux/magic.h>
@@ -47,7 +49,7 @@ typedef u32 erofs_blk_t;
 struct erofs_device_info {
 	char *path;
 	struct erofs_fscache *fscache;
-	struct block_device *bdev;
+	struct bdev_handle *bdev_handle;
 	struct dax_device *dax_dev;
 	u64 dax_part_off;
 
@@ -228,8 +230,6 @@ struct erofs_buf {
 };
 #define __EROFS_BUF_INITIALIZER	((struct erofs_buf){ .page = NULL })
 
-#define ROOT_NID(sb)		((sb)->root_nid)
-
 #define erofs_blknr(sb, addr)	((addr) >> (sb)->s_blocksize_bits)
 #define erofs_blkoff(sb, addr)	((addr) & ((sb)->s_blocksize - 1))
 #define erofs_pos(sb, blk)	((erofs_off_t)(blk) << (sb)->s_blocksize_bits)
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index d4f631d39f..f0110a78ac 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -130,24 +130,24 @@ static void *erofs_find_target_block(struct erofs_buf *target,
 			/* string comparison without already matched prefix */
 			diff = erofs_dirnamecmp(name, &dname, &matched);
 
-			if (!diff) {
-				*_ndirents = 0;
-				goto out;
-			} else if (diff > 0) {
-				head = mid + 1;
-				startprfx = matched;
-
-				if (!IS_ERR(candidate))
-					erofs_put_metabuf(target);
-				*target = buf;
-				candidate = de;
-				*_ndirents = ndirents;
-			} else {
+			if (diff < 0) {
 				erofs_put_metabuf(&buf);
-
 				back = mid - 1;
 				endprfx = matched;
+				continue;
+			}
+
+			if (!IS_ERR(candidate))
+				erofs_put_metabuf(target);
+			*target = buf;
+			if (!diff) {
+				*_ndirents = 0;
+				return de;
 			}
+			head = mid + 1;
+			startprfx = matched;
+			candidate = de;
+			*_ndirents = ndirents;
 			continue;
 		}
 out:		/* free if the candidate is valid */
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index cc44fb2e00..3789d62245 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -4,14 +4,11 @@
  *             https://www.huawei.com/
  * Copyright (C) 2021, Alibaba Cloud
  */
-#include <linux/module.h>
 #include <linux/statfs.h>
-#include <linux/parser.h>
 #include <linux/seq_file.h>
 #include <linux/crc32c.h>
 #include <linux/fs_context.h>
 #include <linux/fs_parser.h>
-#include <linux/dax.h>
 #include <linux/exportfs.h>
 #include "xattr.h"
 
@@ -174,7 +171,7 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	struct erofs_fscache *fscache;
 	struct erofs_deviceslot *dis;
-	struct block_device *bdev;
+	struct bdev_handle *bdev_handle;
 	void *ptr;
 
 	ptr = erofs_read_metabuf(buf, sb, erofs_blknr(sb, *pos), EROFS_KMAP);
@@ -198,13 +195,13 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 			return PTR_ERR(fscache);
 		dif->fscache = fscache;
 	} else if (!sbi->devs->flatdev) {
-		bdev = blkdev_get_by_path(dif->path, BLK_OPEN_READ, sb->s_type,
-					  NULL);
-		if (IS_ERR(bdev))
-			return PTR_ERR(bdev);
-		dif->bdev = bdev;
-		dif->dax_dev = fs_dax_get_by_bdev(bdev, &dif->dax_part_off,
-						  NULL, NULL);
+		bdev_handle = bdev_open_by_path(dif->path, BLK_OPEN_READ,
+						sb->s_type, NULL);
+		if (IS_ERR(bdev_handle))
+			return PTR_ERR(bdev_handle);
+		dif->bdev_handle = bdev_handle;
+		dif->dax_dev = fs_dax_get_by_bdev(bdev_handle->bdev,
+				&dif->dax_part_off, NULL, NULL);
 	}
 
 	dif->blocks = le32_to_cpu(dis->blocks);
@@ -570,6 +567,7 @@ static struct dentry *erofs_get_parent(struct dentry *child)
 }
 
 static const struct export_operations erofs_export_ops = {
+	.encode_fh = generic_encode_ino32_fh,
 	.fh_to_dentry = erofs_fh_to_dentry,
 	.fh_to_parent = erofs_fh_to_parent,
 	.get_parent = erofs_get_parent,
@@ -668,13 +666,13 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 	xa_init(&sbi->managed_pslots);
 #endif
 
-	inode = erofs_iget(sb, ROOT_NID(sbi));
+	inode = erofs_iget(sb, sbi->root_nid);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
 	if (!S_ISDIR(inode->i_mode)) {
 		erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
-			  ROOT_NID(sbi), inode->i_mode);
+			  sbi->root_nid, inode->i_mode);
 		iput(inode);
 		return -EINVAL;
 	}
@@ -704,7 +702,7 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (err)
 		return err;
 
-	erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi));
+	erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
 	return 0;
 }
 
@@ -750,8 +748,8 @@ static int erofs_release_device_info(int id, void *ptr, void *data)
 	struct erofs_device_info *dif = ptr;
 
 	fs_put_dax(dif->dax_dev, NULL);
-	if (dif->bdev)
-		blkdev_put(dif->bdev, &erofs_fs_type);
+	if (dif->bdev_handle)
+		bdev_release(dif->bdev_handle);
 	erofs_fscache_unregister_cookie(dif->fscache);
 	dif->fscache = NULL;
 	kfree(dif->path);
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index 4256a85719..5dea308764 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -264,19 +264,24 @@ static unsigned long erofs_shrink_scan(struct shrinker *shrink,
 	return freed;
 }
 
-static struct shrinker erofs_shrinker_info = {
-	.scan_objects = erofs_shrink_scan,
-	.count_objects = erofs_shrink_count,
-	.seeks = DEFAULT_SEEKS,
-};
+static struct shrinker *erofs_shrinker_info;
 
 int __init erofs_init_shrinker(void)
 {
-	return register_shrinker(&erofs_shrinker_info, "erofs-shrinker");
+	erofs_shrinker_info = shrinker_alloc(0, "erofs-shrinker");
+	if (!erofs_shrinker_info)
+		return -ENOMEM;
+
+	erofs_shrinker_info->count_objects = erofs_shrink_count;
+	erofs_shrinker_info->scan_objects = erofs_shrink_scan;
+
+	shrinker_register(erofs_shrinker_info);
+
+	return 0;
 }
 
 void erofs_exit_shrinker(void)
 {
-	unregister_shrinker(&erofs_shrinker_info);
+	shrinker_free(erofs_shrinker_info);
 }
 #endif	/* !CONFIG_EROFS_FS_ZIP */
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 09d341675e..b58316b49a 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -168,7 +168,7 @@ const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
 };
 #endif
 
-const struct xattr_handler *erofs_xattr_handlers[] = {
+const struct xattr_handler * const erofs_xattr_handlers[] = {
 	&erofs_xattr_user_handler,
 	&erofs_xattr_trusted_handler,
 #ifdef CONFIG_EROFS_FS_SECURITY
diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
index f16283cb8c..b246cd0e13 100644
--- a/fs/erofs/xattr.h
+++ b/fs/erofs/xattr.h
@@ -23,7 +23,7 @@ static inline const char *erofs_xattr_prefix(unsigned int idx,
 {
 	const struct xattr_handler *handler = NULL;
 
-	static const struct xattr_handler *xattr_handler_map[] = {
+	static const struct xattr_handler * const xattr_handler_map[] = {
 		[EROFS_XATTR_INDEX_USER] = &erofs_xattr_user_handler,
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
 		[EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &nop_posix_acl_access,
@@ -44,7 +44,7 @@ static inline const char *erofs_xattr_prefix(unsigned int idx,
 	return xattr_prefix(handler);
 }
 
-extern const struct xattr_handler *erofs_xattr_handlers[];
+extern const struct xattr_handler * const erofs_xattr_handlers[];
 
 int erofs_xattr_prefixes_init(struct super_block *sb);
 void erofs_xattr_prefixes_cleanup(struct super_block *sb);
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index a33cd6757f..1c0e6167d8 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -815,7 +815,6 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
 
 	if (ztailpacking) {
 		pcl->obj.index = 0;	/* which indicates ztailpacking */
-		pcl->pageofs_in = erofs_blkoff(fe->inode->i_sb, map->m_pa);
 		pcl->tailpacking_size = map->m_plen;
 	} else {
 		pcl->obj.index = map->m_pa >> PAGE_SHIFT;
@@ -893,6 +892,7 @@ static int z_erofs_pcluster_begin(struct z_erofs_decompress_frontend *fe)
 		}
 		get_page(map->buf.page);
 		WRITE_ONCE(fe->pcl->compressed_bvecs[0].page, map->buf.page);
+		fe->pcl->pageofs_in = map->m_pa & ~PAGE_MASK;
 		fe->mode = Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE;
 	}
 	/* file-backed inplace I/O pages are traversed in reverse order */
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 7a1a24ae4a..e313c93635 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -82,29 +82,26 @@ static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m,
 }
 
 static unsigned int decode_compactedbits(unsigned int lobits,
-					 unsigned int lomask,
 					 u8 *in, unsigned int pos, u8 *type)
 {
 	const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7);
-	const unsigned int lo = v & lomask;
+	const unsigned int lo = v & ((1 << lobits) - 1);
 
 	*type = (v >> lobits) & 3;
 	return lo;
 }
 
-static int get_compacted_la_distance(unsigned int lclusterbits,
+static int get_compacted_la_distance(unsigned int lobits,
 				     unsigned int encodebits,
 				     unsigned int vcnt, u8 *in, int i)
 {
-	const unsigned int lomask = (1 << lclusterbits) - 1;
 	unsigned int lo, d1 = 0;
 	u8 type;
 
 	DBG_BUGON(i >= vcnt);
 
 	do {
-		lo = decode_compactedbits(lclusterbits, lomask,
-					  in, encodebits * i, &type);
+		lo = decode_compactedbits(lobits, in, encodebits * i, &type);
 
 		if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD)
 			return d1;
@@ -123,15 +120,14 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 {
 	struct erofs_inode *const vi = EROFS_I(m->inode);
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
-	const unsigned int lomask = (1 << lclusterbits) - 1;
-	unsigned int vcnt, base, lo, encodebits, nblk, eofs;
+	unsigned int vcnt, base, lo, lobits, encodebits, nblk, eofs;
 	int i;
 	u8 *in, type;
 	bool big_pcluster;
 
 	if (1 << amortizedshift == 4 && lclusterbits <= 14)
 		vcnt = 2;
-	else if (1 << amortizedshift == 2 && lclusterbits == 12)
+	else if (1 << amortizedshift == 2 && lclusterbits <= 12)
 		vcnt = 16;
 	else
 		return -EOPNOTSUPP;
@@ -140,6 +136,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 	m->nextpackoff = round_down(pos, vcnt << amortizedshift) +
 			 (vcnt << amortizedshift);
 	big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+	lobits = max(lclusterbits, ilog2(Z_EROFS_LI_D0_CBLKCNT) + 1U);
 	encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
 	eofs = erofs_blkoff(m->inode->i_sb, pos);
 	base = round_down(eofs, vcnt << amortizedshift);
@@ -147,15 +144,14 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 
 	i = (eofs - base) >> amortizedshift;
 
-	lo = decode_compactedbits(lclusterbits, lomask,
-				  in, encodebits * i, &type);
+	lo = decode_compactedbits(lobits, in, encodebits * i, &type);
 	m->type = type;
 	if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
 		m->clusterofs = 1 << lclusterbits;
 
 		/* figure out lookahead_distance: delta[1] if needed */
 		if (lookahead)
-			m->delta[1] = get_compacted_la_distance(lclusterbits,
+			m->delta[1] = get_compacted_la_distance(lobits,
 						encodebits, vcnt, in, i);
 		if (lo & Z_EROFS_LI_D0_CBLKCNT) {
 			if (!big_pcluster) {
@@ -174,8 +170,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 		 * of which lo saves delta[1] rather than delta[0].
 		 * Hence, get delta[0] by the previous lcluster indirectly.
 		 */
-		lo = decode_compactedbits(lclusterbits, lomask,
-					  in, encodebits * (i - 1), &type);
+		lo = decode_compactedbits(lobits, in,
+					  encodebits * (i - 1), &type);
 		if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD)
 			lo = 0;
 		else if (lo & Z_EROFS_LI_D0_CBLKCNT)
@@ -190,8 +186,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 		nblk = 1;
 		while (i > 0) {
 			--i;
-			lo = decode_compactedbits(lclusterbits, lomask,
-						  in, encodebits * i, &type);
+			lo = decode_compactedbits(lobits, in,
+						  encodebits * i, &type);
 			if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD)
 				i -= lo;
 
@@ -202,8 +198,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 		nblk = 0;
 		while (i > 0) {
 			--i;
-			lo = decode_compactedbits(lclusterbits, lomask,
-						  in, encodebits * i, &type);
+			lo = decode_compactedbits(lobits, in,
+						  encodebits * i, &type);
 			if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
 				if (lo & Z_EROFS_LI_D0_CBLKCNT) {
 					--i;