1 files changed, 675 insertions, 197 deletions

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 057e6d7b5b7f..2cf96ce1c32e 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2017-2018 HUAWEI, Inc.
- *             http://www.huawei.com/
- * Created by Gao Xiang <gaoxiang25@huawei.com>
+ *             https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
  */
 #include <linux/module.h>
 #include <linux/buffer_head.h>
@@ -10,6 +10,10 @@
 #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"
 
 #define CREATE_TRACE_POINTS
@@ -81,7 +85,7 @@ static void erofs_inode_init_once(void *ptr)
 static struct inode *erofs_alloc_inode(struct super_block *sb)
 {
 	struct erofs_inode *vi =
-		kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
+		alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL);
 
 	if (!vi)
 		return NULL;
@@ -120,24 +124,223 @@ static bool check_layout_compatibility(struct super_block *sb,
 	return true;
 }
 
+#ifdef CONFIG_EROFS_FS_ZIP
+/* read variable-sized metadata, offset will be aligned by 4-byte */
+static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
+				 erofs_off_t *offset, int *lengthp)
+{
+	u8 *buffer, *ptr;
+	int len, i, cnt;
+
+	*offset = round_up(*offset, 4);
+	ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), EROFS_KMAP);
+	if (IS_ERR(ptr))
+		return ptr;
+
+	len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(*offset)]);
+	if (!len)
+		len = U16_MAX + 1;
+	buffer = kmalloc(len, GFP_KERNEL);
+	if (!buffer)
+		return ERR_PTR(-ENOMEM);
+	*offset += sizeof(__le16);
+	*lengthp = len;
+
+	for (i = 0; i < len; i += cnt) {
+		cnt = min(EROFS_BLKSIZ - (int)erofs_blkoff(*offset), len - i);
+		ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset),
+					 EROFS_KMAP);
+		if (IS_ERR(ptr)) {
+			kfree(buffer);
+			return ptr;
+		}
+		memcpy(buffer + i, ptr + erofs_blkoff(*offset), cnt);
+		*offset += cnt;
+	}
+	return buffer;
+}
+
+static int erofs_load_compr_cfgs(struct super_block *sb,
+				 struct erofs_super_block *dsb)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+	unsigned int algs, alg;
+	erofs_off_t offset;
+	int size, ret = 0;
+
+	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
+	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
+		erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
+			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
+		return -EINVAL;
+	}
+
+	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
+	alg = 0;
+	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
+		void *data;
+
+		if (!(algs & 1))
+			continue;
+
+		data = erofs_read_metadata(sb, &buf, &offset, &size);
+		if (IS_ERR(data)) {
+			ret = PTR_ERR(data);
+			break;
+		}
+
+		switch (alg) {
+		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;
+		}
+		kfree(data);
+		if (ret)
+			break;
+	}
+	erofs_put_metabuf(&buf);
+	return ret;
+}
+#else
+static int erofs_load_compr_cfgs(struct super_block *sb,
+				 struct erofs_super_block *dsb)
+{
+	if (dsb->u1.available_compr_algs) {
+		erofs_err(sb, "try to load compressed fs when compression is disabled");
+		return -EINVAL;
+	}
+	return 0;
+}
+#endif
+
+static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
+			     struct erofs_device_info *dif, erofs_off_t *pos)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_fscache *fscache;
+	struct erofs_deviceslot *dis;
+	struct block_device *bdev;
+	void *ptr;
+
+	ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*pos), EROFS_KMAP);
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+	dis = ptr + erofs_blkoff(*pos);
+
+	if (!dif->path) {
+		if (!dis->tag[0]) {
+			erofs_err(sb, "empty device tag @ pos %llu", *pos);
+			return -EINVAL;
+		}
+		dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
+		if (!dif->path)
+			return -ENOMEM;
+	}
+
+	if (erofs_is_fscache_mode(sb)) {
+		fscache = erofs_fscache_register_cookie(sb, dif->path, false);
+		if (IS_ERR(fscache))
+			return PTR_ERR(fscache);
+		dif->fscache = fscache;
+	} else {
+		bdev = blkdev_get_by_path(dif->path, FMODE_READ | FMODE_EXCL,
+					  sb->s_type);
+		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);
+	}
+
+	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;
+	return 0;
+}
+
+static int erofs_scan_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 erofs_buf buf = __EROFS_BUF_INITIALIZER;
+	struct erofs_device_info *dif;
+	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 (sbi->devs->extra_devices &&
+	    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);
+	if (sbi->devs->extra_devices) {
+		idr_for_each_entry(&sbi->devs->tree, dif, id) {
+			err = erofs_init_device(&buf, sb, dif, &pos);
+			if (err)
+				break;
+		}
+	} else {
+		for (id = 0; id < ondisk_extradevs; id++) {
+			dif = kzalloc(sizeof(*dif), GFP_KERNEL);
+			if (!dif) {
+				err = -ENOMEM;
+				break;
+			}
+
+			err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
+			if (err < 0) {
+				kfree(dif);
+				break;
+			}
+			++sbi->devs->extra_devices;
+
+			err = erofs_init_device(&buf, sb, dif, &pos);
+			if (err)
+				break;
+		}
+	}
+	up_read(&sbi->devs->rwsem);
+	erofs_put_metabuf(&buf);
+	return err;
+}
+
 static int erofs_read_superblock(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi;
-	struct page *page;
+	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
 	struct erofs_super_block *dsb;
 	unsigned int blkszbits;
 	void *data;
 	int ret;
 
-	page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping, 0, NULL);
-	if (IS_ERR(page)) {
+	data = erofs_read_metabuf(&buf, sb, 0, EROFS_KMAP);
+	if (IS_ERR(data)) {
 		erofs_err(sb, "cannot read erofs superblock");
-		return PTR_ERR(page);
+		return PTR_ERR(data);
 	}
 
 	sbi = EROFS_SB(sb);
-
-	data = kmap(page);
 	dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
 
 	ret = -EINVAL;
@@ -147,30 +350,48 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 
 	sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
-	if (sbi->feature_compat & EROFS_FEATURE_COMPAT_SB_CHKSUM) {
+	if (erofs_sb_has_sb_chksum(sbi)) {
 		ret = erofs_superblock_csum_verify(sb, data);
 		if (ret)
 			goto out;
 	}
 
+	ret = -EINVAL;
 	blkszbits = dsb->blkszbits;
 	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
 	if (blkszbits != LOG_BLOCK_SIZE) {
-		erofs_err(sb, "blksize %u isn't supported on this platform",
-			  1 << blkszbits);
+		erofs_err(sb, "blkszbits %u isn't supported on this platform",
+			  blkszbits);
 		goto out;
 	}
 
 	if (!check_layout_compatibility(sb, dsb))
 		goto out;
 
-	sbi->blocks = le32_to_cpu(dsb->blocks);
+	sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
+	if (sbi->sb_size > EROFS_BLKSIZ) {
+		erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
+			  sbi->sb_size);
+		goto out;
+	}
+	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);
 #endif
 	sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
 	sbi->root_nid = le16_to_cpu(dsb->root_nid);
+#ifdef CONFIG_EROFS_FS_ZIP
+	sbi->packed_inode = NULL;
+	if (erofs_sb_has_fragments(sbi) && dsb->packed_nid) {
+		sbi->packed_inode =
+			erofs_iget(sb, le64_to_cpu(dsb->packed_nid));
+		if (IS_ERR(sbi->packed_inode)) {
+			ret = PTR_ERR(sbi->packed_inode);
+			goto out;
+		}
+	}
+#endif
 	sbi->inos = le64_to_cpu(dsb->inos);
 
 	sbi->build_time = le64_to_cpu(dsb->build_time);
@@ -185,139 +406,199 @@ static int erofs_read_superblock(struct super_block *sb)
 		ret = -EFSCORRUPTED;
 		goto out;
 	}
-	ret = 0;
-out:
-	kunmap(page);
-	put_page(page);
-	return ret;
-}
-
-#ifdef CONFIG_EROFS_FS_ZIP
-static int erofs_build_cache_strategy(struct super_block *sb,
-				      substring_t *args)
-{
-	struct erofs_sb_info *sbi = EROFS_SB(sb);
-	const char *cs = match_strdup(args);
-	int err = 0;
 
-	if (!cs) {
-		erofs_err(sb, "Not enough memory to store cache strategy");
-		return -ENOMEM;
-	}
+	/* parse on-disk compression configurations */
+	if (erofs_sb_has_compr_cfgs(sbi))
+		ret = erofs_load_compr_cfgs(sb, dsb);
+	else
+		ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	if (ret < 0)
+		goto out;
 
-	if (!strcmp(cs, "disabled")) {
-		sbi->cache_strategy = EROFS_ZIP_CACHE_DISABLED;
-	} else if (!strcmp(cs, "readahead")) {
-		sbi->cache_strategy = EROFS_ZIP_CACHE_READAHEAD;
-	} else if (!strcmp(cs, "readaround")) {
-		sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
-	} else {
-		erofs_err(sb, "Unrecognized cache strategy \"%s\"", cs);
-		err = -EINVAL;
-	}
-	kfree(cs);
-	return err;
-}
-#else
-static int erofs_build_cache_strategy(struct super_block *sb,
-				      substring_t *args)
-{
-	erofs_info(sb, "EROFS compression is disabled, so cache strategy is ignored");
-	return 0;
+	/* handle multiple devices */
+	ret = erofs_scan_devices(sb, dsb);
+
+	if (erofs_sb_has_ztailpacking(sbi))
+		erofs_info(sb, "EXPERIMENTAL compressed inline data feature in use. Use at your own risk!");
+	if (erofs_is_fscache_mode(sb))
+		erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!");
+	if (erofs_sb_has_fragments(sbi))
+		erofs_info(sb, "EXPERIMENTAL compressed fragments feature in use. Use at your own risk!");
+	if (erofs_sb_has_dedupe(sbi))
+		erofs_info(sb, "EXPERIMENTAL global deduplication feature in use. Use at your own risk!");
+out:
+	erofs_put_metabuf(&buf);
+	return ret;
 }
-#endif
 
 /* set up default EROFS parameters */
-static void erofs_default_options(struct erofs_sb_info *sbi)
+static void erofs_default_options(struct erofs_fs_context *ctx)
 {
 #ifdef CONFIG_EROFS_FS_ZIP
-	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
-	sbi->max_sync_decompress_pages = 3;
+	ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
+	ctx->opt.max_sync_decompress_pages = 3;
+	ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
 #endif
 #ifdef CONFIG_EROFS_FS_XATTR
-	set_opt(sbi, XATTR_USER);
+	set_opt(&ctx->opt, XATTR_USER);
 #endif
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
-	set_opt(sbi, POSIX_ACL);
+	set_opt(&ctx->opt, POSIX_ACL);
 #endif
 }
 
 enum {
 	Opt_user_xattr,
-	Opt_nouser_xattr,
 	Opt_acl,
-	Opt_noacl,
 	Opt_cache_strategy,
+	Opt_dax,
+	Opt_dax_enum,
+	Opt_device,
+	Opt_fsid,
+	Opt_domain_id,
 	Opt_err
 };
 
-static match_table_t erofs_tokens = {
-	{Opt_user_xattr, "user_xattr"},
-	{Opt_nouser_xattr, "nouser_xattr"},
-	{Opt_acl, "acl"},
-	{Opt_noacl, "noacl"},
-	{Opt_cache_strategy, "cache_strategy=%s"},
-	{Opt_err, NULL}
+static const struct constant_table erofs_param_cache_strategy[] = {
+	{"disabled",	EROFS_ZIP_CACHE_DISABLED},
+	{"readahead",	EROFS_ZIP_CACHE_READAHEAD},
+	{"readaround",	EROFS_ZIP_CACHE_READAROUND},
+	{}
 };
 
-static int erofs_parse_options(struct super_block *sb, char *options)
-{
-	substring_t args[MAX_OPT_ARGS];
-	char *p;
-	int err;
+static const struct constant_table erofs_dax_param_enums[] = {
+	{"always",	EROFS_MOUNT_DAX_ALWAYS},
+	{"never",	EROFS_MOUNT_DAX_NEVER},
+	{}
+};
 
-	if (!options)
-		return 0;
+static const struct fs_parameter_spec erofs_fs_parameters[] = {
+	fsparam_flag_no("user_xattr",	Opt_user_xattr),
+	fsparam_flag_no("acl",		Opt_acl),
+	fsparam_enum("cache_strategy",	Opt_cache_strategy,
+		     erofs_param_cache_strategy),
+	fsparam_flag("dax",             Opt_dax),
+	fsparam_enum("dax",		Opt_dax_enum, erofs_dax_param_enums),
+	fsparam_string("device",	Opt_device),
+	fsparam_string("fsid",		Opt_fsid),
+	fsparam_string("domain_id",	Opt_domain_id),
+	{}
+};
 
-	while ((p = strsep(&options, ","))) {
-		int token;
+static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
+{
+#ifdef CONFIG_FS_DAX
+	struct erofs_fs_context *ctx = fc->fs_private;
+
+	switch (mode) {
+	case EROFS_MOUNT_DAX_ALWAYS:
+		warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
+		set_opt(&ctx->opt, DAX_ALWAYS);
+		clear_opt(&ctx->opt, DAX_NEVER);
+		return true;
+	case EROFS_MOUNT_DAX_NEVER:
+		set_opt(&ctx->opt, DAX_NEVER);
+		clear_opt(&ctx->opt, DAX_ALWAYS);
+		return true;
+	default:
+		DBG_BUGON(1);
+		return false;
+	}
+#else
+	errorfc(fc, "dax options not supported");
+	return false;
+#endif
+}
 
-		if (!*p)
-			continue;
+static int erofs_fc_parse_param(struct fs_context *fc,
+				struct fs_parameter *param)
+{
+	struct erofs_fs_context *ctx = fc->fs_private;
+	struct fs_parse_result result;
+	struct erofs_device_info *dif;
+	int opt, ret;
 
-		args[0].to = args[0].from = NULL;
-		token = match_token(p, erofs_tokens, args);
+	opt = fs_parse(fc, erofs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
 
-		switch (token) {
+	switch (opt) {
+	case Opt_user_xattr:
 #ifdef CONFIG_EROFS_FS_XATTR
-		case Opt_user_xattr:
-			set_opt(EROFS_SB(sb), XATTR_USER);
-			break;
-		case Opt_nouser_xattr:
-			clear_opt(EROFS_SB(sb), XATTR_USER);
-			break;
+		if (result.boolean)
+			set_opt(&ctx->opt, XATTR_USER);
+		else
+			clear_opt(&ctx->opt, XATTR_USER);
 #else
-		case Opt_user_xattr:
-			erofs_info(sb, "user_xattr options not supported");
-			break;
-		case Opt_nouser_xattr:
-			erofs_info(sb, "nouser_xattr options not supported");
-			break;
+		errorfc(fc, "{,no}user_xattr options not supported");
 #endif
+		break;
+	case Opt_acl:
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
-		case Opt_acl:
-			set_opt(EROFS_SB(sb), POSIX_ACL);
-			break;
-		case Opt_noacl:
-			clear_opt(EROFS_SB(sb), POSIX_ACL);
-			break;
+		if (result.boolean)
+			set_opt(&ctx->opt, POSIX_ACL);
+		else
+			clear_opt(&ctx->opt, POSIX_ACL);
 #else
-		case Opt_acl:
-			erofs_info(sb, "acl options not supported");
-			break;
-		case Opt_noacl:
-			erofs_info(sb, "noacl options not supported");
-			break;
+		errorfc(fc, "{,no}acl options not supported");
 #endif
-		case Opt_cache_strategy:
-			err = erofs_build_cache_strategy(sb, args);
-			if (err)
-				return err;
-			break;
-		default:
-			erofs_err(sb, "Unrecognized mount option \"%s\" or missing value", p);
+		break;
+	case Opt_cache_strategy:
+#ifdef CONFIG_EROFS_FS_ZIP
+		ctx->opt.cache_strategy = result.uint_32;
+#else
+		errorfc(fc, "compression not supported, cache_strategy ignored");
+#endif
+		break;
+	case Opt_dax:
+		if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
 			return -EINVAL;
+		break;
+	case Opt_dax_enum:
+		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;
+	case Opt_fsid:
+#ifdef CONFIG_EROFS_FS_ONDEMAND
+		kfree(ctx->opt.fsid);
+		ctx->opt.fsid = kstrdup(param->string, GFP_KERNEL);
+		if (!ctx->opt.fsid)
+			return -ENOMEM;
+#else
+		errorfc(fc, "fsid option not supported");
+#endif
+		break;
+	case Opt_domain_id:
+#ifdef CONFIG_EROFS_FS_ONDEMAND
+		kfree(ctx->opt.domain_id);
+		ctx->opt.domain_id = kstrdup(param->string, GFP_KERNEL);
+		if (!ctx->opt.domain_id)
+			return -ENOMEM;
+#else
+		errorfc(fc, "domain_id option not supported");
+#endif
+		break;
+	default:
+		return -ENOPARAM;
 	}
 	return 0;
 }
@@ -325,39 +606,43 @@ static int erofs_parse_options(struct super_block *sb, char *options)
 #ifdef CONFIG_EROFS_FS_ZIP
 static const struct address_space_operations managed_cache_aops;
 
-static int erofs_managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
+static bool erofs_managed_cache_release_folio(struct folio *folio, gfp_t gfp)
 {
-	int ret = 1;	/* 0 - busy */
-	struct address_space *const mapping = page->mapping;
+	bool ret = true;
+	struct address_space *const mapping = folio->mapping;
 
-	DBG_BUGON(!PageLocked(page));
+	DBG_BUGON(!folio_test_locked(folio));
 	DBG_BUGON(mapping->a_ops != &managed_cache_aops);
 
-	if (PagePrivate(page))
-		ret = erofs_try_to_free_cached_page(mapping, page);
+	if (folio_test_private(folio))
+		ret = erofs_try_to_free_cached_page(&folio->page);
 
 	return ret;
 }
 
-static void erofs_managed_cache_invalidatepage(struct page *page,
-					       unsigned int offset,
-					       unsigned int length)
+/*
+ * It will be called only on inode eviction. In case that there are still some
+ * decompression requests in progress, wait with rescheduling for a bit here.
+ * We could introduce an extra locking instead but it seems unnecessary.
+ */
+static void erofs_managed_cache_invalidate_folio(struct folio *folio,
+					       size_t offset, size_t length)
 {
-	const unsigned int stop = length + offset;
+	const size_t stop = length + offset;
 
-	DBG_BUGON(!PageLocked(page));
+	DBG_BUGON(!folio_test_locked(folio));
 
 	/* Check for potential overflow in debug mode */
-	DBG_BUGON(stop > PAGE_SIZE || stop < length);
+	DBG_BUGON(stop > folio_size(folio) || stop < length);
 
-	if (offset == 0 && stop == PAGE_SIZE)
-		while (!erofs_managed_cache_releasepage(page, GFP_NOFS))
+	if (offset == 0 && stop == folio_size(folio))
+		while (!erofs_managed_cache_release_folio(folio, GFP_NOFS))
 			cond_resched();
 }
 
 static const struct address_space_operations managed_cache_aops = {
-	.releasepage = erofs_managed_cache_releasepage,
-	.invalidatepage = erofs_managed_cache_invalidatepage,
+	.release_folio = erofs_managed_cache_release_folio,
+	.invalidate_folio = erofs_managed_cache_invalidate_folio,
 };
 
 static int erofs_init_managed_cache(struct super_block *sb)
@@ -372,8 +657,7 @@ static int erofs_init_managed_cache(struct super_block *sb)
 	inode->i_size = OFFSET_MAX;
 
 	inode->i_mapping->a_ops = &managed_cache_aops;
-	mapping_set_gfp_mask(inode->i_mapping,
-			     GFP_NOFS | __GFP_HIGHMEM | __GFP_MOVABLE);
+	mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
 	sbi->managed_cache = inode;
 	return 0;
 }
@@ -381,55 +665,124 @@ static int erofs_init_managed_cache(struct super_block *sb)
 static int erofs_init_managed_cache(struct super_block *sb) { return 0; }
 #endif
 
-static int erofs_fill_super(struct super_block *sb, void *data, int silent)
+static struct inode *erofs_nfs_get_inode(struct super_block *sb,
+					 u64 ino, u32 generation)
+{
+	return erofs_iget(sb, ino);
+}
+
+static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
+		struct fid *fid, int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    erofs_nfs_get_inode);
+}
+
+static struct dentry *erofs_fh_to_parent(struct super_block *sb,
+		struct fid *fid, int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    erofs_nfs_get_inode);
+}
+
+static struct dentry *erofs_get_parent(struct dentry *child)
+{
+	erofs_nid_t nid;
+	unsigned int d_type;
+	int err;
+
+	err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
+	if (err)
+		return ERR_PTR(err);
+	return d_obtain_alias(erofs_iget(child->d_sb, nid));
+}
+
+static const struct export_operations erofs_export_ops = {
+	.fh_to_dentry = erofs_fh_to_dentry,
+	.fh_to_parent = erofs_fh_to_parent,
+	.get_parent = erofs_get_parent,
+};
+
+static int erofs_fc_fill_pseudo_super(struct super_block *sb, struct fs_context *fc)
+{
+	static const struct tree_descr empty_descr = {""};
+
+	return simple_fill_super(sb, EROFS_SUPER_MAGIC, &empty_descr);
+}
+
+static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct inode *inode;
 	struct erofs_sb_info *sbi;
+	struct erofs_fs_context *ctx = fc->fs_private;
 	int err;
 
 	sb->s_magic = EROFS_SUPER_MAGIC;
-
-	if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
-		erofs_err(sb, "failed to set erofs blksize");
-		return -EINVAL;
-	}
+	sb->s_flags |= SB_RDONLY | SB_NOATIME;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_op = &erofs_sops;
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
 		return -ENOMEM;
 
 	sb->s_fs_info = sbi;
+	sbi->opt = ctx->opt;
+	ctx->opt.fsid = NULL;
+	ctx->opt.domain_id = NULL;
+	sbi->devs = ctx->devs;
+	ctx->devs = NULL;
+
+	if (erofs_is_fscache_mode(sb)) {
+		sb->s_blocksize = EROFS_BLKSIZ;
+		sb->s_blocksize_bits = LOG_BLOCK_SIZE;
+
+		err = erofs_fscache_register_fs(sb);
+		if (err)
+			return err;
+
+		err = super_setup_bdi(sb);
+		if (err)
+			return err;
+	} else {
+		if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
+			erofs_err(sb, "failed to set erofs blksize");
+			return -EINVAL;
+		}
+
+		sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
+						  &sbi->dax_part_off,
+						  NULL, NULL);
+	}
+
 	err = erofs_read_superblock(sb);
 	if (err)
 		return err;
 
-	sb->s_flags |= SB_RDONLY | SB_NOATIME;
-	sb->s_maxbytes = MAX_LFS_FILESIZE;
-	sb->s_time_gran = 1;
+	if (test_opt(&sbi->opt, DAX_ALWAYS)) {
+		BUILD_BUG_ON(EROFS_BLKSIZ != PAGE_SIZE);
 
-	sb->s_op = &erofs_sops;
+		if (!sbi->dax_dev) {
+			errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
+			clear_opt(&sbi->opt, DAX_ALWAYS);
+		}
+	}
 
-#ifdef CONFIG_EROFS_FS_XATTR
+	sb->s_time_gran = 1;
 	sb->s_xattr = erofs_xattr_handlers;
-#endif
-	/* set erofs default mount options */
-	erofs_default_options(sbi);
-
-	err = erofs_parse_options(sb, data);
-	if (err)
-		return err;
+	sb->s_export_op = &erofs_export_ops;
 
-	if (test_opt(sbi, POSIX_ACL))
+	if (test_opt(&sbi->opt, POSIX_ACL))
 		sb->s_flags |= SB_POSIXACL;
 	else
 		sb->s_flags &= ~SB_POSIXACL;
 
 #ifdef CONFIG_EROFS_FS_ZIP
-	INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC);
+	xa_init(&sbi->managed_pslots);
 #endif
 
 	/* get the root inode */
-	inode = erofs_iget(sb, ROOT_NID(sbi), true);
+	inode = erofs_iget(sb, ROOT_NID(sbi));
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
@@ -450,15 +803,117 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	if (err)
 		return err;
 
-	erofs_info(sb, "mounted with opts: %s, root inode @ nid %llu.",
-		   (char *)data, ROOT_NID(sbi));
+	err = erofs_register_sysfs(sb);
+	if (err)
+		return err;
+
+	erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi));
 	return 0;
 }
 
-static struct dentry *erofs_mount(struct file_system_type *fs_type, int flags,
-				  const char *dev_name, void *data)
+static int erofs_fc_anon_get_tree(struct fs_context *fc)
 {
-	return mount_bdev(fs_type, flags, dev_name, data, erofs_fill_super);
+	return get_tree_nodev(fc, erofs_fc_fill_pseudo_super);
+}
+
+static int erofs_fc_get_tree(struct fs_context *fc)
+{
+	struct erofs_fs_context *ctx = fc->fs_private;
+
+	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->opt.fsid)
+		return get_tree_nodev(fc, erofs_fc_fill_super);
+
+	return get_tree_bdev(fc, erofs_fc_fill_super);
+}
+
+static int erofs_fc_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_fs_context *ctx = fc->fs_private;
+
+	DBG_BUGON(!sb_rdonly(sb));
+
+	if (test_opt(&ctx->opt, POSIX_ACL))
+		fc->sb_flags |= SB_POSIXACL;
+	else
+		fc->sb_flags &= ~SB_POSIXACL;
+
+	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, NULL);
+	if (dif->bdev)
+		blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL);
+	erofs_fscache_unregister_cookie(dif->fscache);
+	dif->fscache = NULL;
+	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)
+{
+	struct erofs_fs_context *ctx = fc->fs_private;
+
+	erofs_free_dev_context(ctx->devs);
+	kfree(ctx->opt.fsid);
+	kfree(ctx->opt.domain_id);
+	kfree(ctx);
+}
+
+static const struct fs_context_operations erofs_context_ops = {
+	.parse_param	= erofs_fc_parse_param,
+	.get_tree       = erofs_fc_get_tree,
+	.reconfigure    = erofs_fc_reconfigure,
+	.free		= erofs_fc_free,
+};
+
+static const struct fs_context_operations erofs_anon_context_ops = {
+	.get_tree       = erofs_fc_anon_get_tree,
+};
+
+static int erofs_init_fs_context(struct fs_context *fc)
+{
+	struct erofs_fs_context *ctx;
+
+	/* pseudo mount for anon inodes */
+	if (fc->sb_flags & SB_KERNMOUNT) {
+		fc->ops = &erofs_anon_context_ops;
+		return 0;
+	}
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	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;
 }
 
 /*
@@ -471,11 +926,26 @@ static void erofs_kill_sb(struct super_block *sb)
 
 	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
 
-	kill_block_super(sb);
+	/* pseudo mount for anon inodes */
+	if (sb->s_flags & SB_KERNMOUNT) {
+		kill_anon_super(sb);
+		return;
+	}
+
+	if (erofs_is_fscache_mode(sb))
+		kill_anon_super(sb);
+	else
+		kill_block_super(sb);
 
 	sbi = EROFS_SB(sb);
 	if (!sbi)
 		return;
+
+	erofs_free_dev_context(sbi->devs);
+	fs_put_dax(sbi->dax_dev, NULL);
+	erofs_fscache_unregister_fs(sb);
+	kfree(sbi->opt.fsid);
+	kfree(sbi->opt.domain_id);
 	kfree(sbi);
 	sb->s_fs_info = NULL;
 }
@@ -487,19 +957,23 @@ static void erofs_put_super(struct super_block *sb)
 
 	DBG_BUGON(!sbi);
 
+	erofs_unregister_sysfs(sb);
 	erofs_shrinker_unregister(sb);
 #ifdef CONFIG_EROFS_FS_ZIP
 	iput(sbi->managed_cache);
 	sbi->managed_cache = NULL;
+	iput(sbi->packed_inode);
+	sbi->packed_inode = NULL;
 #endif
+	erofs_fscache_unregister_fs(sb);
 }
 
-static struct file_system_type erofs_fs_type = {
+struct file_system_type erofs_fs_type = {
 	.owner          = THIS_MODULE,
 	.name           = "erofs",
-	.mount          = erofs_mount,
+	.init_fs_context = erofs_init_fs_context,
 	.kill_sb        = erofs_kill_sb,
-	.fs_flags       = FS_REQUIRES_DEV,
+	.fs_flags       = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
 };
 MODULE_ALIAS_FS("erofs");
 
@@ -522,10 +996,19 @@ 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)
 		goto zip_err;
 
+	err = erofs_init_sysfs();
+	if (err)
+		goto sysfs_err;
+
 	err = register_filesystem(&erofs_fs_type);
 	if (err)
 		goto fs_err;
@@ -533,8 +1016,12 @@ static int __init erofs_module_init(void)
 	return 0;
 
 fs_err:
+	erofs_exit_sysfs();
+sysfs_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);
@@ -545,12 +1032,16 @@ 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();
+
+	erofs_exit_sysfs();
+	z_erofs_exit_zip_subsystem();
+	z_erofs_lzma_exit();
+	erofs_exit_shrinker();
 	kmem_cache_destroy(erofs_inode_cachep);
+	erofs_pcpubuf_exit();
 }
 
 /* get filesystem statistics */
@@ -558,11 +1049,14 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct super_block *sb = dentry->d_sb;
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
-	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+	u64 id = 0;
+
+	if (!erofs_is_fscache_mode(sb))
+		id = huge_encode_dev(sb->s_bdev->bd_dev);
 
 	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;
@@ -570,69 +1064,54 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 
 	buf->f_namelen = EROFS_NAME_LEN;
 
-	buf->f_fsid.val[0] = (u32)id;
-	buf->f_fsid.val[1] = (u32)(id >> 32);
+	buf->f_fsid    = u64_to_fsid(id);
 	return 0;
 }
 
 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 {
-	struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
+	struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
+	struct erofs_mount_opts *opt = &sbi->opt;
 
 #ifdef CONFIG_EROFS_FS_XATTR
-	if (test_opt(sbi, 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(sbi, POSIX_ACL))
+	if (test_opt(opt, POSIX_ACL))
 		seq_puts(seq, ",acl");
 	else
 		seq_puts(seq, ",noacl");
 #endif
 #ifdef CONFIG_EROFS_FS_ZIP
-	if (sbi->cache_strategy == EROFS_ZIP_CACHE_DISABLED) {
+	if (opt->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
 		seq_puts(seq, ",cache_strategy=disabled");
-	} else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAHEAD) {
+	else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
 		seq_puts(seq, ",cache_strategy=readahead");
-	} else if (sbi->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(opt, DAX_ALWAYS))
+		seq_puts(seq, ",dax=always");
+	if (test_opt(opt, DAX_NEVER))
+		seq_puts(seq, ",dax=never");
+#ifdef CONFIG_EROFS_FS_ONDEMAND
+	if (opt->fsid)
+		seq_printf(seq, ",fsid=%s", opt->fsid);
+	if (opt->domain_id)
+		seq_printf(seq, ",domain_id=%s", opt->domain_id);
 #endif
 	return 0;
 }
 
-static int erofs_remount(struct super_block *sb, int *flags, char *data)
-{
-	struct erofs_sb_info *sbi = EROFS_SB(sb);
-	unsigned int org_mnt_opt = sbi->mount_opt;
-	int err;
-
-	DBG_BUGON(!sb_rdonly(sb));
-	err = erofs_parse_options(sb, data);
-	if (err)
-		goto out;
-
-	if (test_opt(sbi, POSIX_ACL))
-		sb->s_flags |= SB_POSIXACL;
-	else
-		sb->s_flags &= ~SB_POSIXACL;
-
-	*flags |= SB_RDONLY;
-	return 0;
-out:
-	sbi->mount_opt = org_mnt_opt;
-	return err;
-}
-
 const struct super_operations erofs_sops = {
 	.put_super = erofs_put_super,
 	.alloc_inode = erofs_alloc_inode,
 	.free_inode = erofs_free_inode,
 	.statfs = erofs_statfs,
 	.show_options = erofs_show_options,
-	.remount_fs = erofs_remount,
 };
 
 module_init(erofs_module_init);
@@ -641,4 +1120,3 @@ module_exit(erofs_module_exit);
 MODULE_DESCRIPTION("Enhanced ROM File System");
 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
 MODULE_LICENSE("GPL");
-