1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 *             https://www.huawei.com/
5 * Copyright (C) 2021, Alibaba Cloud
6 */
7#include "internal.h"
8#include <linux/sched/mm.h>
9#include <trace/events/erofs.h>
10
11void erofs_unmap_metabuf(struct erofs_buf *buf)
12{
13	if (buf->kmap_type == EROFS_KMAP)
14		kunmap_local(buf->base);
15	buf->base = NULL;
16	buf->kmap_type = EROFS_NO_KMAP;
17}
18
19void erofs_put_metabuf(struct erofs_buf *buf)
20{
21	if (!buf->page)
22		return;
23	erofs_unmap_metabuf(buf);
24	put_page(buf->page);
25	buf->page = NULL;
26}
27
28/*
29 * Derive the block size from inode->i_blkbits to make compatible with
30 * anonymous inode in fscache mode.
31 */
32void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
33		  enum erofs_kmap_type type)
34{
35	struct inode *inode = buf->inode;
36	erofs_off_t offset = (erofs_off_t)blkaddr << inode->i_blkbits;
37	pgoff_t index = offset >> PAGE_SHIFT;
38	struct page *page = buf->page;
39	struct folio *folio;
40	unsigned int nofs_flag;
41
42	if (!page || page->index != index) {
43		erofs_put_metabuf(buf);
44
45		nofs_flag = memalloc_nofs_save();
46		folio = read_cache_folio(inode->i_mapping, index, NULL, NULL);
47		memalloc_nofs_restore(nofs_flag);
48		if (IS_ERR(folio))
49			return folio;
50
51		/* should already be PageUptodate, no need to lock page */
52		page = folio_file_page(folio, index);
53		buf->page = page;
54	}
55	if (buf->kmap_type == EROFS_NO_KMAP) {
56		if (type == EROFS_KMAP)
57			buf->base = kmap_local_page(page);
58		buf->kmap_type = type;
59	} else if (buf->kmap_type != type) {
60		DBG_BUGON(1);
61		return ERR_PTR(-EFAULT);
62	}
63	if (type == EROFS_NO_KMAP)
64		return NULL;
65	return buf->base + (offset & ~PAGE_MASK);
66}
67
68void erofs_init_metabuf(struct erofs_buf *buf, struct super_block *sb)
69{
70	if (erofs_is_fscache_mode(sb))
71		buf->inode = EROFS_SB(sb)->s_fscache->inode;
72	else
73		buf->inode = sb->s_bdev->bd_inode;
74}
75
76void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
77			 erofs_blk_t blkaddr, enum erofs_kmap_type type)
78{
79	erofs_init_metabuf(buf, sb);
80	return erofs_bread(buf, blkaddr, type);
81}
82
83static int erofs_map_blocks_flatmode(struct inode *inode,
84				     struct erofs_map_blocks *map)
85{
86	erofs_blk_t nblocks, lastblk;
87	u64 offset = map->m_la;
88	struct erofs_inode *vi = EROFS_I(inode);
89	struct super_block *sb = inode->i_sb;
90	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
91
92	nblocks = erofs_iblks(inode);
93	lastblk = nblocks - tailendpacking;
94
95	/* there is no hole in flatmode */
96	map->m_flags = EROFS_MAP_MAPPED;
97	if (offset < erofs_pos(sb, lastblk)) {
98		map->m_pa = erofs_pos(sb, vi->raw_blkaddr) + map->m_la;
99		map->m_plen = erofs_pos(sb, lastblk) - offset;
100	} else if (tailendpacking) {
101		map->m_pa = erofs_iloc(inode) + vi->inode_isize +
102			vi->xattr_isize + erofs_blkoff(sb, offset);
103		map->m_plen = inode->i_size - offset;
104
105		/* inline data should be located in the same meta block */
106		if (erofs_blkoff(sb, map->m_pa) + map->m_plen > sb->s_blocksize) {
107			erofs_err(sb, "inline data cross block boundary @ nid %llu",
108				  vi->nid);
109			DBG_BUGON(1);
110			return -EFSCORRUPTED;
111		}
112		map->m_flags |= EROFS_MAP_META;
113	} else {
114		erofs_err(sb, "internal error @ nid: %llu (size %llu), m_la 0x%llx",
115			  vi->nid, inode->i_size, map->m_la);
116		DBG_BUGON(1);
117		return -EIO;
118	}
119	return 0;
120}
121
122int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map)
123{
124	struct super_block *sb = inode->i_sb;
125	struct erofs_inode *vi = EROFS_I(inode);
126	struct erofs_inode_chunk_index *idx;
127	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
128	u64 chunknr;
129	unsigned int unit;
130	erofs_off_t pos;
131	void *kaddr;
132	int err = 0;
133
134	trace_erofs_map_blocks_enter(inode, map, 0);
135	map->m_deviceid = 0;
136	if (map->m_la >= inode->i_size) {
137		/* leave out-of-bound access unmapped */
138		map->m_flags = 0;
139		map->m_plen = 0;
140		goto out;
141	}
142
143	if (vi->datalayout != EROFS_INODE_CHUNK_BASED) {
144		err = erofs_map_blocks_flatmode(inode, map);
145		goto out;
146	}
147
148	if (vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES)
149		unit = sizeof(*idx);			/* chunk index */
150	else
151		unit = EROFS_BLOCK_MAP_ENTRY_SIZE;	/* block map */
152
153	chunknr = map->m_la >> vi->chunkbits;
154	pos = ALIGN(erofs_iloc(inode) + vi->inode_isize +
155		    vi->xattr_isize, unit) + unit * chunknr;
156
157	kaddr = erofs_read_metabuf(&buf, sb, erofs_blknr(sb, pos), EROFS_KMAP);
158	if (IS_ERR(kaddr)) {
159		err = PTR_ERR(kaddr);
160		goto out;
161	}
162	map->m_la = chunknr << vi->chunkbits;
163	map->m_plen = min_t(erofs_off_t, 1UL << vi->chunkbits,
164			round_up(inode->i_size - map->m_la, sb->s_blocksize));
165
166	/* handle block map */
167	if (!(vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES)) {
168		__le32 *blkaddr = kaddr + erofs_blkoff(sb, pos);
169
170		if (le32_to_cpu(*blkaddr) == EROFS_NULL_ADDR) {
171			map->m_flags = 0;
172		} else {
173			map->m_pa = erofs_pos(sb, le32_to_cpu(*blkaddr));
174			map->m_flags = EROFS_MAP_MAPPED;
175		}
176		goto out_unlock;
177	}
178	/* parse chunk indexes */
179	idx = kaddr + erofs_blkoff(sb, pos);
180	switch (le32_to_cpu(idx->blkaddr)) {
181	case EROFS_NULL_ADDR:
182		map->m_flags = 0;
183		break;
184	default:
185		map->m_deviceid = le16_to_cpu(idx->device_id) &
186			EROFS_SB(sb)->device_id_mask;
187		map->m_pa = erofs_pos(sb, le32_to_cpu(idx->blkaddr));
188		map->m_flags = EROFS_MAP_MAPPED;
189		break;
190	}
191out_unlock:
192	erofs_put_metabuf(&buf);
193out:
194	if (!err)
195		map->m_llen = map->m_plen;
196	trace_erofs_map_blocks_exit(inode, map, 0, err);
197	return err;
198}
199
200int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
201{
202	struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
203	struct erofs_device_info *dif;
204	int id;
205
206	map->m_bdev = sb->s_bdev;
207	map->m_daxdev = EROFS_SB(sb)->dax_dev;
208	map->m_dax_part_off = EROFS_SB(sb)->dax_part_off;
209	map->m_fscache = EROFS_SB(sb)->s_fscache;
210
211	if (map->m_deviceid) {
212		down_read(&devs->rwsem);
213		dif = idr_find(&devs->tree, map->m_deviceid - 1);
214		if (!dif) {
215			up_read(&devs->rwsem);
216			return -ENODEV;
217		}
218		if (devs->flatdev) {
219			map->m_pa += erofs_pos(sb, dif->mapped_blkaddr);
220			up_read(&devs->rwsem);
221			return 0;
222		}
223		map->m_bdev = dif->bdev_file ? file_bdev(dif->bdev_file) : NULL;
224		map->m_daxdev = dif->dax_dev;
225		map->m_dax_part_off = dif->dax_part_off;
226		map->m_fscache = dif->fscache;
227		up_read(&devs->rwsem);
228	} else if (devs->extra_devices && !devs->flatdev) {
229		down_read(&devs->rwsem);
230		idr_for_each_entry(&devs->tree, dif, id) {
231			erofs_off_t startoff, length;
232
233			if (!dif->mapped_blkaddr)
234				continue;
235			startoff = erofs_pos(sb, dif->mapped_blkaddr);
236			length = erofs_pos(sb, dif->blocks);
237
238			if (map->m_pa >= startoff &&
239			    map->m_pa < startoff + length) {
240				map->m_pa -= startoff;
241				map->m_bdev = dif->bdev_file ?
242					      file_bdev(dif->bdev_file) : NULL;
243				map->m_daxdev = dif->dax_dev;
244				map->m_dax_part_off = dif->dax_part_off;
245				map->m_fscache = dif->fscache;
246				break;
247			}
248		}
249		up_read(&devs->rwsem);
250	}
251	return 0;
252}
253
254static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
255		unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
256{
257	int ret;
258	struct super_block *sb = inode->i_sb;
259	struct erofs_map_blocks map;
260	struct erofs_map_dev mdev;
261
262	map.m_la = offset;
263	map.m_llen = length;
264
265	ret = erofs_map_blocks(inode, &map);
266	if (ret < 0)
267		return ret;
268
269	mdev = (struct erofs_map_dev) {
270		.m_deviceid = map.m_deviceid,
271		.m_pa = map.m_pa,
272	};
273	ret = erofs_map_dev(sb, &mdev);
274	if (ret)
275		return ret;
276
277	iomap->offset = map.m_la;
278	if (flags & IOMAP_DAX)
279		iomap->dax_dev = mdev.m_daxdev;
280	else
281		iomap->bdev = mdev.m_bdev;
282	iomap->length = map.m_llen;
283	iomap->flags = 0;
284	iomap->private = NULL;
285
286	if (!(map.m_flags & EROFS_MAP_MAPPED)) {
287		iomap->type = IOMAP_HOLE;
288		iomap->addr = IOMAP_NULL_ADDR;
289		if (!iomap->length)
290			iomap->length = length;
291		return 0;
292	}
293
294	if (map.m_flags & EROFS_MAP_META) {
295		void *ptr;
296		struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
297
298		iomap->type = IOMAP_INLINE;
299		ptr = erofs_read_metabuf(&buf, sb,
300				erofs_blknr(sb, mdev.m_pa), EROFS_KMAP);
301		if (IS_ERR(ptr))
302			return PTR_ERR(ptr);
303		iomap->inline_data = ptr + erofs_blkoff(sb, mdev.m_pa);
304		iomap->private = buf.base;
305	} else {
306		iomap->type = IOMAP_MAPPED;
307		iomap->addr = mdev.m_pa;
308		if (flags & IOMAP_DAX)
309			iomap->addr += mdev.m_dax_part_off;
310	}
311	return 0;
312}
313
314static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
315		ssize_t written, unsigned int flags, struct iomap *iomap)
316{
317	void *ptr = iomap->private;
318
319	if (ptr) {
320		struct erofs_buf buf = {
321			.page = kmap_to_page(ptr),
322			.base = ptr,
323			.kmap_type = EROFS_KMAP,
324		};
325
326		DBG_BUGON(iomap->type != IOMAP_INLINE);
327		erofs_put_metabuf(&buf);
328	} else {
329		DBG_BUGON(iomap->type == IOMAP_INLINE);
330	}
331	return written;
332}
333
334static const struct iomap_ops erofs_iomap_ops = {
335	.iomap_begin = erofs_iomap_begin,
336	.iomap_end = erofs_iomap_end,
337};
338
339int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
340		 u64 start, u64 len)
341{
342	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
343#ifdef CONFIG_EROFS_FS_ZIP
344		return iomap_fiemap(inode, fieinfo, start, len,
345				    &z_erofs_iomap_report_ops);
346#else
347		return -EOPNOTSUPP;
348#endif
349	}
350	return iomap_fiemap(inode, fieinfo, start, len, &erofs_iomap_ops);
351}
352
353/*
354 * since we dont have write or truncate flows, so no inode
355 * locking needs to be held at the moment.
356 */
357static int erofs_read_folio(struct file *file, struct folio *folio)
358{
359	return iomap_read_folio(folio, &erofs_iomap_ops);
360}
361
362static void erofs_readahead(struct readahead_control *rac)
363{
364	return iomap_readahead(rac, &erofs_iomap_ops);
365}
366
367static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
368{
369	return iomap_bmap(mapping, block, &erofs_iomap_ops);
370}
371
372static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
373{
374	struct inode *inode = file_inode(iocb->ki_filp);
375
376	/* no need taking (shared) inode lock since it's a ro filesystem */
377	if (!iov_iter_count(to))
378		return 0;
379
380#ifdef CONFIG_FS_DAX
381	if (IS_DAX(inode))
382		return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
383#endif
384	if (iocb->ki_flags & IOCB_DIRECT) {
385		struct block_device *bdev = inode->i_sb->s_bdev;
386		unsigned int blksize_mask;
387
388		if (bdev)
389			blksize_mask = bdev_logical_block_size(bdev) - 1;
390		else
391			blksize_mask = i_blocksize(inode) - 1;
392
393		if ((iocb->ki_pos | iov_iter_count(to) |
394		     iov_iter_alignment(to)) & blksize_mask)
395			return -EINVAL;
396
397		return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
398				    NULL, 0, NULL, 0);
399	}
400	return filemap_read(iocb, to, 0);
401}
402
403/* for uncompressed (aligned) files and raw access for other files */
404const struct address_space_operations erofs_raw_access_aops = {
405	.read_folio = erofs_read_folio,
406	.readahead = erofs_readahead,
407	.bmap = erofs_bmap,
408	.direct_IO = noop_direct_IO,
409	.release_folio = iomap_release_folio,
410	.invalidate_folio = iomap_invalidate_folio,
411};
412
413#ifdef CONFIG_FS_DAX
414static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf,
415		unsigned int order)
416{
417	return dax_iomap_fault(vmf, order, NULL, NULL, &erofs_iomap_ops);
418}
419
420static vm_fault_t erofs_dax_fault(struct vm_fault *vmf)
421{
422	return erofs_dax_huge_fault(vmf, 0);
423}
424
425static const struct vm_operations_struct erofs_dax_vm_ops = {
426	.fault		= erofs_dax_fault,
427	.huge_fault	= erofs_dax_huge_fault,
428};
429
430static int erofs_file_mmap(struct file *file, struct vm_area_struct *vma)
431{
432	if (!IS_DAX(file_inode(file)))
433		return generic_file_readonly_mmap(file, vma);
434
435	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
436		return -EINVAL;
437
438	vma->vm_ops = &erofs_dax_vm_ops;
439	vm_flags_set(vma, VM_HUGEPAGE);
440	return 0;
441}
442#else
443#define erofs_file_mmap	generic_file_readonly_mmap
444#endif
445
446const struct file_operations erofs_file_fops = {
447	.llseek		= generic_file_llseek,
448	.read_iter	= erofs_file_read_iter,
449	.mmap		= erofs_file_mmap,
450	.get_unmapped_area = thp_get_unmapped_area,
451	.splice_read	= filemap_splice_read,
452};
453