fs/erofs/inode.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2017-2018 HUAWEI, Inc.
  *             https://www.huawei.com/
  * Copyright (C) 2021, Alibaba Cloud
  */
 #include "xattr.h"

 #include <trace/events/erofs.h>

 static void *erofs_read_inode(struct erofs_buf *buf,
 			      struct inode *inode, unsigned int *ofs)
 {
 	struct super_block *sb = inode->i_sb;
 	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;
 	unsigned int ifmt;
 	int err;

 	blkaddr = erofs_blknr(sb, inode_loc);
 	*ofs = erofs_blkoff(sb, inode_loc);

 	erofs_dbg("%s, reading inode nid %llu at %u of blkaddr %u",
 		  __func__, vi->nid, *ofs, blkaddr);

 	kaddr = erofs_read_metabuf(buf, sb, blkaddr, EROFS_KMAP);
 	if (IS_ERR(kaddr)) {
 		erofs_err(sb, "failed to get inode (nid: %llu) page, err %ld",
 			  vi->nid, PTR_ERR(kaddr));
 		return kaddr;
 	}

 	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",
 			  ifmt, vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
 	}

 	vi->datalayout = erofs_inode_datalayout(ifmt);
 	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
 		erofs_err(inode->i_sb, "unsupported datalayout %u of nid %llu",
 			  vi->datalayout, vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
 	}

 	switch (erofs_inode_version(ifmt)) {
 	case EROFS_INODE_LAYOUT_EXTENDED:
 		vi->inode_isize = sizeof(struct erofs_inode_extended);
 		/* check if the extended inode acrosses block boundary */
 		if (*ofs + vi->inode_isize <= sb->s_blocksize) {
 			*ofs += vi->inode_isize;
 			die = (struct erofs_inode_extended *)dic;
 		} else {
 			const unsigned int gotten = sb->s_blocksize - *ofs;

 			copied = kmalloc(vi->inode_isize, GFP_NOFS);
 			if (!copied) {
 				err = -ENOMEM;
 				goto err_out;
 			}
 			memcpy(copied, dic, gotten);
 			kaddr = erofs_read_metabuf(buf, sb, blkaddr + 1,
 						   EROFS_KMAP);
 			if (IS_ERR(kaddr)) {
 				erofs_err(sb, "failed to get inode payload block (nid: %llu), err %ld",
 					  vi->nid, PTR_ERR(kaddr));
 				kfree(copied);
 				return kaddr;
 			}
 			*ofs = vi->inode_isize - gotten;
 			memcpy((u8 *)copied + gotten, kaddr, *ofs);
 			die = copied;
 		}
 		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;
 		}
 		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 */
 		inode->i_ctime.tv_sec = le64_to_cpu(die->i_mtime);
 		inode->i_ctime.tv_nsec = 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;
 	case EROFS_INODE_LAYOUT_COMPACT:
 		vi->inode_isize = sizeof(struct erofs_inode_compact);
 		*ofs += vi->inode_isize;
 		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;
 		}
 		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->i_ctime.tv_sec = sbi->build_time;
 		inode->i_ctime.tv_nsec = 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_inode_version(ifmt), vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
 	}

 	if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
 		if (vi->chunkformat & ~EROFS_CHUNK_FORMAT_ALL) {
 			erofs_err(inode->i_sb,
 				  "unsupported chunk format %x of nid %llu",
 				  vi->chunkformat, vi->nid);
 			err = -EOPNOTSUPP;
 			goto err_out;
 		}
 		vi->chunkbits = sb->s_blocksize_bits +
 			(vi->chunkformat & EROFS_CHUNK_FORMAT_BLKBITS_MASK);
 	}
 	inode->i_mtime.tv_sec = inode->i_ctime.tv_sec;
 	inode->i_atime.tv_sec = inode->i_ctime.tv_sec;
 	inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec;
 	inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec;

 	inode->i_flags &= ~S_DAX;
 	if (test_opt(&sbi->opt, DAX_ALWAYS) && S_ISREG(inode->i_mode) &&
 	    (vi->datalayout == EROFS_INODE_FLAT_PLAIN ||
 	     vi->datalayout == EROFS_INODE_CHUNK_BASED))
 		inode->i_flags |= S_DAX;

 	if (!nblks)
 		/* measure inode.i_blocks as generic filesystems */
 		inode->i_blocks = round_up(inode->i_size, sb->s_blocksize) >> 9;
 	else
 		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);
 	erofs_put_metabuf(buf);
 	return ERR_PTR(err);
 }

 static int erofs_fill_symlink(struct inode *inode, void *kaddr,
 			      unsigned int m_pofs)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 	unsigned int bsz = i_blocksize(inode);
 	char *lnk;

 	/* if it cannot be handled with fast symlink scheme */
 	if (vi->datalayout != EROFS_INODE_FLAT_INLINE ||
 	    inode->i_size >= bsz || inode->i_size < 0) {
 		inode->i_op = &erofs_symlink_iops;
 		return 0;
 	}

 	lnk = kmalloc(inode->i_size + 1, GFP_KERNEL);
 	if (!lnk)
 		return -ENOMEM;

 	m_pofs += vi->xattr_isize;
 	/* inline symlink data shouldn't cross block boundary */
 	if (m_pofs + inode->i_size > bsz) {
 		kfree(lnk);
 		erofs_err(inode->i_sb,
 			  "inline data cross block boundary @ nid %llu",
 			  vi->nid);
 		DBG_BUGON(1);
 		return -EFSCORRUPTED;
 	}
 	memcpy(lnk, kaddr + m_pofs, inode->i_size);
 	lnk[inode->i_size] = '\0';

 	inode->i_link = lnk;
 	inode->i_op = &erofs_fast_symlink_iops;
 	return 0;
 }

 static int erofs_fill_inode(struct inode *inode)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
 	void *kaddr;
 	unsigned int ofs;
 	int err = 0;

 	trace_erofs_fill_inode(inode);

 	/* read inode base data from disk */
 	kaddr = erofs_read_inode(&buf, inode, &ofs);
 	if (IS_ERR(kaddr))
 		return PTR_ERR(kaddr);

 	/* setup the new inode */
 	switch (inode->i_mode & S_IFMT) {
 	case S_IFREG:
 		inode->i_op = &erofs_generic_iops;
 		if (erofs_inode_is_data_compressed(vi->datalayout))
 			inode->i_fop = &generic_ro_fops;
 		else
 			inode->i_fop = &erofs_file_fops;
 		break;
 	case S_IFDIR:
 		inode->i_op = &erofs_dir_iops;
 		inode->i_fop = &erofs_dir_fops;
 		break;
 	case S_IFLNK:
 		err = erofs_fill_symlink(inode, kaddr, ofs);
 		if (err)
 			goto out_unlock;
 		inode_nohighmem(inode);
 		break;
 	case S_IFCHR:
 	case S_IFBLK:
 	case S_IFIFO:
 	case S_IFSOCK:
 		inode->i_op = &erofs_generic_iops;
 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 		goto out_unlock;
 	default:
 		err = -EFSCORRUPTED;
 		goto out_unlock;
 	}

 	if (erofs_inode_is_data_compressed(vi->datalayout)) {
 		if (!erofs_is_fscache_mode(inode->i_sb)) {
 			DO_ONCE_LITE_IF(inode->i_sb->s_blocksize != PAGE_SIZE,
 				  erofs_info, inode->i_sb,
 				  "EXPERIMENTAL EROFS subpage compressed block support in use. Use at your own risk!");
 			err = z_erofs_fill_inode(inode);
                 }
 		else
 			err = -EOPNOTSUPP;
 		goto out_unlock;
 	}
 	inode->i_mapping->a_ops = &erofs_raw_access_aops;
 	if (!erofs_is_fscache_mode(inode->i_sb))
 		mapping_set_large_folios(inode->i_mapping);
 #ifdef CONFIG_EROFS_FS_ONDEMAND
 	if (erofs_is_fscache_mode(inode->i_sb))
 		inode->i_mapping->a_ops = &erofs_fscache_access_aops;
 #endif

 out_unlock:
 	erofs_put_metabuf(&buf);
 	return err;
 }

 /*
  * erofs nid is 64bits, but i_ino is 'unsigned long', therefore
  * we should do more for 32-bit platform to find the right inode.
  */
 static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
 {
 	const erofs_nid_t nid = *(erofs_nid_t *)opaque;

 	return EROFS_I(inode)->nid == nid;
 }

 static int erofs_iget_set_actor(struct inode *inode, void *opaque)
 {
 	const erofs_nid_t nid = *(erofs_nid_t *)opaque;

 	inode->i_ino = erofs_inode_hash(nid);
 	return 0;
 }

 struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid)
 {
 	const unsigned long hashval = erofs_inode_hash(nid);
 	struct inode *inode;

 	inode = iget5_locked(sb, hashval, erofs_ilookup_test_actor,
 		erofs_iget_set_actor, &nid);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);

 	if (inode->i_state & I_NEW) {
 		int err;
 		struct erofs_inode *vi = EROFS_I(inode);

 		vi->nid = nid;

 		err = erofs_fill_inode(inode);
 		if (!err) {
 			unlock_new_inode(inode);
 		} else {
 			iget_failed(inode);
 			inode = ERR_PTR(err);
 		}
 	}
 	return inode;
 }

 int erofs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		  struct kstat *stat, u32 request_mask,
 		  unsigned int query_flags)
 {
 	struct inode *const inode = d_inode(path->dentry);

 	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout))
 		stat->attributes |= STATX_ATTR_COMPRESSED;

 	stat->attributes |= STATX_ATTR_IMMUTABLE;
 	stat->attributes_mask |= (STATX_ATTR_COMPRESSED |
 				  STATX_ATTR_IMMUTABLE);

 	generic_fillattr(mnt_userns, inode, stat);
 	return 0;
 }

 const struct inode_operations erofs_generic_iops = {
 	.getattr = erofs_getattr,
 	.listxattr = erofs_listxattr,
 	.get_acl = erofs_get_acl,
 	.fiemap = erofs_fiemap,
 };

 const struct inode_operations erofs_symlink_iops = {
 	.get_link = page_get_link,
 	.getattr = erofs_getattr,
 	.listxattr = erofs_listxattr,
 	.get_acl = erofs_get_acl,
 };

 const struct inode_operations erofs_fast_symlink_iops = {
 	.get_link = simple_get_link,
 	.getattr = erofs_getattr,
 	.listxattr = erofs_listxattr,
 	.get_acl = erofs_get_acl,
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2017-2018 HUAWEI, Inc.
	* https://www.huawei.com/
	* Copyright (C) 2021, Alibaba Cloud
	*/
	#include "xattr.h"

	#include <trace/events/erofs.h>

	static void erofs_read_inode(struct erofs_buf buf,
	struct inode inode, unsigned int ofs)
	{
	struct super_block *sb = inode->i_sb;
	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;
	unsigned int ifmt;
	int err;

	blkaddr = erofs_blknr(sb, inode_loc);
	*ofs = erofs_blkoff(sb, inode_loc);

	erofs_dbg("%s, reading inode nid %llu at %u of blkaddr %u",
	__func__, vi->nid, *ofs, blkaddr);

	kaddr = erofs_read_metabuf(buf, sb, blkaddr, EROFS_KMAP);
	if (IS_ERR(kaddr)) {
	erofs_err(sb, "failed to get inode (nid: %llu) page, err %ld",
	vi->nid, PTR_ERR(kaddr));
	return kaddr;
	}

	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",
	ifmt, vi->nid);
	err = -EOPNOTSUPP;
	goto err_out;
	}

	vi->datalayout = erofs_inode_datalayout(ifmt);
	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
	erofs_err(inode->i_sb, "unsupported datalayout %u of nid %llu",
	vi->datalayout, vi->nid);
	err = -EOPNOTSUPP;
	goto err_out;
	}

	switch (erofs_inode_version(ifmt)) {
	case EROFS_INODE_LAYOUT_EXTENDED:
	vi->inode_isize = sizeof(struct erofs_inode_extended);
	/* check if the extended inode acrosses block boundary */
	if (*ofs + vi->inode_isize <= sb->s_blocksize) {
	*ofs += vi->inode_isize;
	die = (struct erofs_inode_extended *)dic;
	} else {
	const unsigned int gotten = sb->s_blocksize - *ofs;

	copied = kmalloc(vi->inode_isize, GFP_NOFS);
	if (!copied) {
	err = -ENOMEM;
	goto err_out;
	}
	memcpy(copied, dic, gotten);
	kaddr = erofs_read_metabuf(buf, sb, blkaddr + 1,
	EROFS_KMAP);
	if (IS_ERR(kaddr)) {
	erofs_err(sb, "failed to get inode payload block (nid: %llu), err %ld",
	vi->nid, PTR_ERR(kaddr));
	kfree(copied);
	return kaddr;
	}
	*ofs = vi->inode_isize - gotten;
	memcpy((u8 )copied + gotten, kaddr, ofs);
	die = copied;
	}
	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;
	}
	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 */
	inode->i_ctime.tv_sec = le64_to_cpu(die->i_mtime);
	inode->i_ctime.tv_nsec = 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;
	case EROFS_INODE_LAYOUT_COMPACT:
	vi->inode_isize = sizeof(struct erofs_inode_compact);
	*ofs += vi->inode_isize;
	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;
	}
	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->i_ctime.tv_sec = sbi->build_time;
	inode->i_ctime.tv_nsec = 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_inode_version(ifmt), vi->nid);
	err = -EOPNOTSUPP;
	goto err_out;
	}

	if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
	if (vi->chunkformat & ~EROFS_CHUNK_FORMAT_ALL) {
	erofs_err(inode->i_sb,
	"unsupported chunk format %x of nid %llu",
	vi->chunkformat, vi->nid);
	err = -EOPNOTSUPP;
	goto err_out;
	}
	vi->chunkbits = sb->s_blocksize_bits +
	(vi->chunkformat & EROFS_CHUNK_FORMAT_BLKBITS_MASK);
	}
	inode->i_mtime.tv_sec = inode->i_ctime.tv_sec;
	inode->i_atime.tv_sec = inode->i_ctime.tv_sec;
	inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec;
	inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec;

	inode->i_flags &= ~S_DAX;
	if (test_opt(&sbi->opt, DAX_ALWAYS) && S_ISREG(inode->i_mode) &&
	(vi->datalayout == EROFS_INODE_FLAT_PLAIN \|\|
	vi->datalayout == EROFS_INODE_CHUNK_BASED))
	inode->i_flags \|= S_DAX;

	if (!nblks)
	/* measure inode.i_blocks as generic filesystems */
	inode->i_blocks = round_up(inode->i_size, sb->s_blocksize) >> 9;
	else
	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);
	erofs_put_metabuf(buf);
	return ERR_PTR(err);
	}

	static int erofs_fill_symlink(struct inode inode, void kaddr,
	unsigned int m_pofs)
	{
	struct erofs_inode *vi = EROFS_I(inode);
	unsigned int bsz = i_blocksize(inode);
	char *lnk;

	/* if it cannot be handled with fast symlink scheme */
	if (vi->datalayout != EROFS_INODE_FLAT_INLINE \|\|
	inode->i_size >= bsz \|\| inode->i_size < 0) {
	inode->i_op = &erofs_symlink_iops;
	return 0;
	}

	lnk = kmalloc(inode->i_size + 1, GFP_KERNEL);
	if (!lnk)
	return -ENOMEM;

	m_pofs += vi->xattr_isize;
	/* inline symlink data shouldn't cross block boundary */
	if (m_pofs + inode->i_size > bsz) {
	kfree(lnk);
	erofs_err(inode->i_sb,
	"inline data cross block boundary @ nid %llu",
	vi->nid);
	DBG_BUGON(1);
	return -EFSCORRUPTED;
	}
	memcpy(lnk, kaddr + m_pofs, inode->i_size);
	lnk[inode->i_size] = '\0';

	inode->i_link = lnk;
	inode->i_op = &erofs_fast_symlink_iops;
	return 0;
	}

	static int erofs_fill_inode(struct inode *inode)
	{
	struct erofs_inode *vi = EROFS_I(inode);
	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
	void *kaddr;
	unsigned int ofs;
	int err = 0;

	trace_erofs_fill_inode(inode);

	/* read inode base data from disk */
	kaddr = erofs_read_inode(&buf, inode, &ofs);
	if (IS_ERR(kaddr))
	return PTR_ERR(kaddr);

	/* setup the new inode */
	switch (inode->i_mode & S_IFMT) {
	case S_IFREG:
	inode->i_op = &erofs_generic_iops;
	if (erofs_inode_is_data_compressed(vi->datalayout))
	inode->i_fop = &generic_ro_fops;
	else
	inode->i_fop = &erofs_file_fops;
	break;
	case S_IFDIR:
	inode->i_op = &erofs_dir_iops;
	inode->i_fop = &erofs_dir_fops;
	break;
	case S_IFLNK:
	err = erofs_fill_symlink(inode, kaddr, ofs);
	if (err)
	goto out_unlock;
	inode_nohighmem(inode);
	break;
	case S_IFCHR:
	case S_IFBLK:
	case S_IFIFO:
	case S_IFSOCK:
	inode->i_op = &erofs_generic_iops;
	init_special_inode(inode, inode->i_mode, inode->i_rdev);
	goto out_unlock;
	default:
	err = -EFSCORRUPTED;
	goto out_unlock;
	}

	if (erofs_inode_is_data_compressed(vi->datalayout)) {
	if (!erofs_is_fscache_mode(inode->i_sb)) {
	DO_ONCE_LITE_IF(inode->i_sb->s_blocksize != PAGE_SIZE,
	erofs_info, inode->i_sb,
	"EXPERIMENTAL EROFS subpage compressed block support in use. Use at your own risk!");
	err = z_erofs_fill_inode(inode);
	}
	else
	err = -EOPNOTSUPP;
	goto out_unlock;
	}
	inode->i_mapping->a_ops = &erofs_raw_access_aops;
	if (!erofs_is_fscache_mode(inode->i_sb))
	mapping_set_large_folios(inode->i_mapping);
	#ifdef CONFIG_EROFS_FS_ONDEMAND
	if (erofs_is_fscache_mode(inode->i_sb))
	inode->i_mapping->a_ops = &erofs_fscache_access_aops;
	#endif

	out_unlock:
	erofs_put_metabuf(&buf);
	return err;
	}

	/*
	* erofs nid is 64bits, but i_ino is 'unsigned long', therefore
	* we should do more for 32-bit platform to find the right inode.
	*/
	static int erofs_ilookup_test_actor(struct inode inode, void opaque)
	{
	const erofs_nid_t nid = (erofs_nid_t )opaque;

	return EROFS_I(inode)->nid == nid;
	}

	static int erofs_iget_set_actor(struct inode inode, void opaque)
	{
	const erofs_nid_t nid = (erofs_nid_t )opaque;

	inode->i_ino = erofs_inode_hash(nid);
	return 0;
	}

	struct inode erofs_iget(struct super_block sb, erofs_nid_t nid)
	{
	const unsigned long hashval = erofs_inode_hash(nid);
	struct inode *inode;

	inode = iget5_locked(sb, hashval, erofs_ilookup_test_actor,
	erofs_iget_set_actor, &nid);
	if (!inode)
	return ERR_PTR(-ENOMEM);

	if (inode->i_state & I_NEW) {
	int err;
	struct erofs_inode *vi = EROFS_I(inode);

	vi->nid = nid;

	err = erofs_fill_inode(inode);
	if (!err) {
	unlock_new_inode(inode);
	} else {
	iget_failed(inode);
	inode = ERR_PTR(err);
	}
	}
	return inode;
	}

	int erofs_getattr(struct user_namespace mnt_userns, const struct path path,
	struct kstat *stat, u32 request_mask,
	unsigned int query_flags)
	{
	struct inode *const inode = d_inode(path->dentry);

	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout))
	stat->attributes \|= STATX_ATTR_COMPRESSED;

	stat->attributes \|= STATX_ATTR_IMMUTABLE;
	stat->attributes_mask \|= (STATX_ATTR_COMPRESSED \|
	STATX_ATTR_IMMUTABLE);

	generic_fillattr(mnt_userns, inode, stat);
	return 0;
	}

	const struct inode_operations erofs_generic_iops = {
	.getattr = erofs_getattr,
	.listxattr = erofs_listxattr,
	.get_acl = erofs_get_acl,
	.fiemap = erofs_fiemap,
	};

	const struct inode_operations erofs_symlink_iops = {
	.get_link = page_get_link,
	.getattr = erofs_getattr,
	.listxattr = erofs_listxattr,
	.get_acl = erofs_get_acl,
	};

	const struct inode_operations erofs_fast_symlink_iops = {
	.get_link = simple_get_link,
	.getattr = erofs_getattr,
	.listxattr = erofs_listxattr,
	.get_acl = erofs_get_acl,
	};