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

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2017-2018 HUAWEI, Inc.
  *             https://www.huawei.com/
  */
 #include "internal.h"
 #include <linux/prefetch.h>
 #include <linux/dax.h>
 #include <trace/events/erofs.h>

 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 {
 	struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;
 	struct page *page;

 	page = read_cache_page_gfp(mapping, blkaddr,
 				   mapping_gfp_constraint(mapping, ~__GFP_FS));
 	/* should already be PageUptodate */
 	if (!IS_ERR(page))
 		lock_page(page);
 	return page;
 }

 static int erofs_map_blocks_flatmode(struct inode *inode,
 				     struct erofs_map_blocks *map,
 				     int flags)
 {
 	int err = 0;
 	erofs_blk_t nblocks, lastblk;
 	u64 offset = map->m_la;
 	struct erofs_inode *vi = EROFS_I(inode);
 	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);

 	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);

 	nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
 	lastblk = nblocks - tailendpacking;

 	if (offset >= inode->i_size) {
 		/* leave out-of-bound access unmapped */
 		map->m_flags = 0;
 		map->m_plen = 0;
 		goto out;
 	}

 	/* there is no hole in flatmode */
 	map->m_flags = EROFS_MAP_MAPPED;

 	if (offset < blknr_to_addr(lastblk)) {
 		map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
 		map->m_plen = blknr_to_addr(lastblk) - offset;
 	} else if (tailendpacking) {
 		/* 2 - inode inline B: inode, [xattrs], inline last blk... */
 		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);

 		map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
 			vi->xattr_isize + erofs_blkoff(map->m_la);
 		map->m_plen = inode->i_size - offset;

 		/* inline data should be located in one meta block */
 		if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
 			erofs_err(inode->i_sb,
 				  "inline data cross block boundary @ nid %llu",
 				  vi->nid);
 			DBG_BUGON(1);
 			err = -EFSCORRUPTED;
 			goto err_out;
 		}

 		map->m_flags |= EROFS_MAP_META;
 	} else {
 		erofs_err(inode->i_sb,
 			  "internal error @ nid: %llu (size %llu), m_la 0x%llx",
 			  vi->nid, inode->i_size, map->m_la);
 		DBG_BUGON(1);
 		err = -EIO;
 		goto err_out;
 	}

 out:
 	map->m_llen = map->m_plen;

 err_out:
 	trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
 	return err;
 }

 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;

 	map.m_la = offset;
 	map.m_llen = length;

 	ret = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW);
 	if (ret < 0)
 		return ret;

 	iomap->bdev = inode->i_sb->s_bdev;
 	iomap->dax_dev = EROFS_I_SB(inode)->dax_dev;
 	iomap->offset = map.m_la;
 	iomap->length = map.m_llen;
 	iomap->flags = 0;
 	iomap->private = NULL;

 	if (!(map.m_flags & EROFS_MAP_MAPPED)) {
 		iomap->type = IOMAP_HOLE;
 		iomap->addr = IOMAP_NULL_ADDR;
 		if (!iomap->length)
 			iomap->length = length;
 		return 0;
 	}

 	if (map.m_flags & EROFS_MAP_META) {
 		struct page *ipage;

 		iomap->type = IOMAP_INLINE;
 		ipage = erofs_get_meta_page(inode->i_sb,
 					    erofs_blknr(map.m_pa));
 		if (IS_ERR(ipage))
 			return PTR_ERR(ipage);
 		iomap->inline_data = page_address(ipage) +
 					erofs_blkoff(map.m_pa);
 		iomap->private = ipage;
 	} else {
 		iomap->type = IOMAP_MAPPED;
 		iomap->addr = map.m_pa;
 	}
 	return 0;
 }

 static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
 		ssize_t written, unsigned int flags, struct iomap *iomap)
 {
 	struct page *ipage = iomap->private;

 	if (ipage) {
 		DBG_BUGON(iomap->type != IOMAP_INLINE);
 		unlock_page(ipage);
 		put_page(ipage);
 	} else {
 		DBG_BUGON(iomap->type == IOMAP_INLINE);
 	}
 	return written;
 }

 static const struct iomap_ops erofs_iomap_ops = {
 	.iomap_begin = erofs_iomap_begin,
 	.iomap_end = erofs_iomap_end,
 };

 int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		 u64 start, u64 len)
 {
 	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
 #ifdef CONFIG_EROFS_FS_ZIP
 		return iomap_fiemap(inode, fieinfo, start, len,
 				    &z_erofs_iomap_report_ops);
 #else
 		return -EOPNOTSUPP;
 #endif
 	}
 	return iomap_fiemap(inode, fieinfo, start, len, &erofs_iomap_ops);
 }

 /*
  * since we dont have write or truncate flows, so no inode
  * locking needs to be held at the moment.
  */
 static int erofs_readpage(struct file *file, struct page *page)
 {
 	return iomap_readpage(page, &erofs_iomap_ops);
 }

 static void erofs_readahead(struct readahead_control *rac)
 {
 	return iomap_readahead(rac, &erofs_iomap_ops);
 }

 static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
 {
 	return iomap_bmap(mapping, block, &erofs_iomap_ops);
 }

 static int erofs_prepare_dio(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct inode *inode = file_inode(iocb->ki_filp);
 	loff_t align = iocb->ki_pos | iov_iter_count(to) |
 		iov_iter_alignment(to);
 	struct block_device *bdev = inode->i_sb->s_bdev;
 	unsigned int blksize_mask;

 	if (bdev)
 		blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1;
 	else
 		blksize_mask = (1 << inode->i_blkbits) - 1;

 	if (align & blksize_mask)
 		return -EINVAL;
 	return 0;
 }

 static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	/* no need taking (shared) inode lock since it's a ro filesystem */
 	if (!iov_iter_count(to))
 		return 0;

 #ifdef CONFIG_FS_DAX
 	if (IS_DAX(iocb->ki_filp->f_mapping->host))
 		return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
 #endif
 	if (iocb->ki_flags & IOCB_DIRECT) {
 		int err = erofs_prepare_dio(iocb, to);

 		if (!err)
 			return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
 					    NULL, 0);
 		if (err < 0)
 			return err;
 	}
 	return filemap_read(iocb, to, 0);
 }

 /* for uncompressed (aligned) files and raw access for other files */
 const struct address_space_operations erofs_raw_access_aops = {
 	.readpage = erofs_readpage,
 	.readahead = erofs_readahead,
 	.bmap = erofs_bmap,
 	.direct_IO = noop_direct_IO,
 };

 #ifdef CONFIG_FS_DAX
 static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf,
 		enum page_entry_size pe_size)
 {
 	return dax_iomap_fault(vmf, pe_size, NULL, NULL, &erofs_iomap_ops);
 }

 static vm_fault_t erofs_dax_fault(struct vm_fault *vmf)
 {
 	return erofs_dax_huge_fault(vmf, PE_SIZE_PTE);
 }

 static const struct vm_operations_struct erofs_dax_vm_ops = {
 	.fault		= erofs_dax_fault,
 	.huge_fault	= erofs_dax_huge_fault,
 };

 static int erofs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	if (!IS_DAX(file_inode(file)))
 		return generic_file_readonly_mmap(file, vma);

 	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
 		return -EINVAL;

 	vma->vm_ops = &erofs_dax_vm_ops;
 	vma->vm_flags |= VM_HUGEPAGE;
 	return 0;
 }
 #else
 #define erofs_file_mmap	generic_file_readonly_mmap
 #endif

 const struct file_operations erofs_file_fops = {
 	.llseek		= generic_file_llseek,
 	.read_iter	= erofs_file_read_iter,
 	.mmap		= erofs_file_mmap,
 	.splice_read	= generic_file_splice_read,
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2017-2018 HUAWEI, Inc.
	* https://www.huawei.com/
	*/
	#include "internal.h"
	#include <linux/prefetch.h>
	#include <linux/dax.h>
	#include <trace/events/erofs.h>

	struct page erofs_get_meta_page(struct super_block sb, erofs_blk_t blkaddr)
	{
	struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;
	struct page *page;

	page = read_cache_page_gfp(mapping, blkaddr,
	mapping_gfp_constraint(mapping, ~__GFP_FS));
	/* should already be PageUptodate */
	if (!IS_ERR(page))
	lock_page(page);
	return page;
	}

	static int erofs_map_blocks_flatmode(struct inode *inode,
	struct erofs_map_blocks *map,
	int flags)
	{
	int err = 0;
	erofs_blk_t nblocks, lastblk;
	u64 offset = map->m_la;
	struct erofs_inode *vi = EROFS_I(inode);
	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);

	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);

	nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
	lastblk = nblocks - tailendpacking;

	if (offset >= inode->i_size) {
	/* leave out-of-bound access unmapped */
	map->m_flags = 0;
	map->m_plen = 0;
	goto out;
	}

	/* there is no hole in flatmode */
	map->m_flags = EROFS_MAP_MAPPED;

	if (offset < blknr_to_addr(lastblk)) {
	map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
	map->m_plen = blknr_to_addr(lastblk) - offset;
	} else if (tailendpacking) {
	/* 2 - inode inline B: inode, [xattrs], inline last blk... */
	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);

	map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
	vi->xattr_isize + erofs_blkoff(map->m_la);
	map->m_plen = inode->i_size - offset;

	/* inline data should be located in one meta block */
	if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
	erofs_err(inode->i_sb,
	"inline data cross block boundary @ nid %llu",
	vi->nid);
	DBG_BUGON(1);
	err = -EFSCORRUPTED;
	goto err_out;
	}

	map->m_flags \|= EROFS_MAP_META;
	} else {
	erofs_err(inode->i_sb,
	"internal error @ nid: %llu (size %llu), m_la 0x%llx",
	vi->nid, inode->i_size, map->m_la);
	DBG_BUGON(1);
	err = -EIO;
	goto err_out;
	}

	out:
	map->m_llen = map->m_plen;

	err_out:
	trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
	return err;
	}

	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;

	map.m_la = offset;
	map.m_llen = length;

	ret = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW);
	if (ret < 0)
	return ret;

	iomap->bdev = inode->i_sb->s_bdev;
	iomap->dax_dev = EROFS_I_SB(inode)->dax_dev;
	iomap->offset = map.m_la;
	iomap->length = map.m_llen;
	iomap->flags = 0;
	iomap->private = NULL;

	if (!(map.m_flags & EROFS_MAP_MAPPED)) {
	iomap->type = IOMAP_HOLE;
	iomap->addr = IOMAP_NULL_ADDR;
	if (!iomap->length)
	iomap->length = length;
	return 0;
	}

	if (map.m_flags & EROFS_MAP_META) {
	struct page *ipage;

	iomap->type = IOMAP_INLINE;
	ipage = erofs_get_meta_page(inode->i_sb,
	erofs_blknr(map.m_pa));
	if (IS_ERR(ipage))
	return PTR_ERR(ipage);
	iomap->inline_data = page_address(ipage) +
	erofs_blkoff(map.m_pa);
	iomap->private = ipage;
	} else {
	iomap->type = IOMAP_MAPPED;
	iomap->addr = map.m_pa;
	}
	return 0;
	}

	static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
	ssize_t written, unsigned int flags, struct iomap *iomap)
	{
	struct page *ipage = iomap->private;

	if (ipage) {
	DBG_BUGON(iomap->type != IOMAP_INLINE);
	unlock_page(ipage);
	put_page(ipage);
	} else {
	DBG_BUGON(iomap->type == IOMAP_INLINE);
	}
	return written;
	}

	static const struct iomap_ops erofs_iomap_ops = {
	.iomap_begin = erofs_iomap_begin,
	.iomap_end = erofs_iomap_end,
	};

	int erofs_fiemap(struct inode inode, struct fiemap_extent_info fieinfo,
	u64 start, u64 len)
	{
	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
	#ifdef CONFIG_EROFS_FS_ZIP
	return iomap_fiemap(inode, fieinfo, start, len,
	&z_erofs_iomap_report_ops);
	#else
	return -EOPNOTSUPP;
	#endif
	}
	return iomap_fiemap(inode, fieinfo, start, len, &erofs_iomap_ops);
	}

	/*
	* since we dont have write or truncate flows, so no inode
	* locking needs to be held at the moment.
	*/
	static int erofs_readpage(struct file file, struct page page)
	{
	return iomap_readpage(page, &erofs_iomap_ops);
	}

	static void erofs_readahead(struct readahead_control *rac)
	{
	return iomap_readahead(rac, &erofs_iomap_ops);
	}

	static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
	{
	return iomap_bmap(mapping, block, &erofs_iomap_ops);
	}

	static int erofs_prepare_dio(struct kiocb iocb, struct iov_iter to)
	{
	struct inode *inode = file_inode(iocb->ki_filp);
	loff_t align = iocb->ki_pos \| iov_iter_count(to) \|
	iov_iter_alignment(to);
	struct block_device *bdev = inode->i_sb->s_bdev;
	unsigned int blksize_mask;

	if (bdev)
	blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1;
	else
	blksize_mask = (1 << inode->i_blkbits) - 1;

	if (align & blksize_mask)
	return -EINVAL;
	return 0;
	}

	static ssize_t erofs_file_read_iter(struct kiocb iocb, struct iov_iter to)
	{
	/* no need taking (shared) inode lock since it's a ro filesystem */
	if (!iov_iter_count(to))
	return 0;

	#ifdef CONFIG_FS_DAX
	if (IS_DAX(iocb->ki_filp->f_mapping->host))
	return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
	#endif
	if (iocb->ki_flags & IOCB_DIRECT) {
	int err = erofs_prepare_dio(iocb, to);

	if (!err)
	return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
	NULL, 0);
	if (err < 0)
	return err;
	}
	return filemap_read(iocb, to, 0);
	}

	/* for uncompressed (aligned) files and raw access for other files */
	const struct address_space_operations erofs_raw_access_aops = {
	.readpage = erofs_readpage,
	.readahead = erofs_readahead,
	.bmap = erofs_bmap,
	.direct_IO = noop_direct_IO,
	};

	#ifdef CONFIG_FS_DAX
	static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf,
	enum page_entry_size pe_size)
	{
	return dax_iomap_fault(vmf, pe_size, NULL, NULL, &erofs_iomap_ops);
	}

	static vm_fault_t erofs_dax_fault(struct vm_fault *vmf)
	{
	return erofs_dax_huge_fault(vmf, PE_SIZE_PTE);
	}

	static const struct vm_operations_struct erofs_dax_vm_ops = {
	.fault = erofs_dax_fault,
	.huge_fault = erofs_dax_huge_fault,
	};

	static int erofs_file_mmap(struct file file, struct vm_area_struct vma)
	{
	if (!IS_DAX(file_inode(file)))
	return generic_file_readonly_mmap(file, vma);

	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
	return -EINVAL;

	vma->vm_ops = &erofs_dax_vm_ops;
	vma->vm_flags \|= VM_HUGEPAGE;
	return 0;
	}
	#else
	#define erofs_file_mmap generic_file_readonly_mmap
	#endif

	const struct file_operations erofs_file_fops = {
	.llseek = generic_file_llseek,
	.read_iter = erofs_file_read_iter,
	.mmap = erofs_file_mmap,
	.splice_read = generic_file_splice_read,
	};