file.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  linux/fs/hpfs/file.c
  4 *
  5 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
  6 *
  7 *  file VFS functions
  8 */
  9
 10#include "hpfs_fn.h"
 11#include <linux/mpage.h>
 12#include <linux/iomap.h>
 13#include <linux/fiemap.h>
 14
 15#define BLOCKS(size) (((size) + 511) >> 9)
 16
 17static int hpfs_file_release(struct inode *inode, struct file *file)
 18{
 19	hpfs_lock(inode->i_sb);
 20	hpfs_write_if_changed(inode);
 21	hpfs_unlock(inode->i_sb);
 22	return 0;
 23}
 24
 25int hpfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 26{
 27	struct inode *inode = file->f_mapping->host;
 28	int ret;
 29
 30	ret = file_write_and_wait_range(file, start, end);
 31	if (ret)
 32		return ret;
 33	return sync_blockdev(inode->i_sb->s_bdev);
 34}
 35
 36/*
 37 * generic_file_read often calls bmap with non-existing sector,
 38 * so we must ignore such errors.
 39 */
 40
 41static secno hpfs_bmap(struct inode *inode, unsigned file_secno, unsigned *n_secs)
 42{
 43	struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
 44	unsigned n, disk_secno;
 45	struct fnode *fnode;
 46	struct buffer_head *bh;
 47	if (BLOCKS(hpfs_i(inode)->mmu_private) <= file_secno) return 0;
 48	n = file_secno - hpfs_inode->i_file_sec;
 49	if (n < hpfs_inode->i_n_secs) {
 50		*n_secs = hpfs_inode->i_n_secs - n;
 51		return hpfs_inode->i_disk_sec + n;
 52	}
 53	if (!(fnode = hpfs_map_fnode(inode->i_sb, inode->i_ino, &bh))) return 0;
 54	disk_secno = hpfs_bplus_lookup(inode->i_sb, inode,
 55				       GET_BTREE_PTR(&fnode->btree),
 56				       file_secno, bh);
 57	if (disk_secno == -1) return 0;
 58	if (hpfs_chk_sectors(inode->i_sb, disk_secno, 1, "bmap")) return 0;
 59	n = file_secno - hpfs_inode->i_file_sec;
 60	if (n < hpfs_inode->i_n_secs) {
 61		*n_secs = hpfs_inode->i_n_secs - n;
 62		return hpfs_inode->i_disk_sec + n;
 63	}
 64	*n_secs = 1;
 65	return disk_secno;
 66}
 67
 68void hpfs_truncate(struct inode *i)
 69{
 70	if (IS_IMMUTABLE(i)) return /*-EPERM*/;
 71	hpfs_lock_assert(i->i_sb);
 72
 73	hpfs_i(i)->i_n_secs = 0;
 74	i->i_blocks = 1 + ((i->i_size + 511) >> 9);
 75	hpfs_i(i)->mmu_private = i->i_size;
 76	hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9));
 77	hpfs_write_inode(i);
 78	hpfs_i(i)->i_n_secs = 0;
 79}
 80
 81static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
 82{
 83	int r;
 84	secno s;
 85	unsigned n_secs;
 86	hpfs_lock(inode->i_sb);
 87	s = hpfs_bmap(inode, iblock, &n_secs);
 88	if (s) {
 89		if (bh_result->b_size >> 9 < n_secs)
 90			n_secs = bh_result->b_size >> 9;
 91		n_secs = hpfs_search_hotfix_map_for_range(inode->i_sb, s, n_secs);
 92		if (unlikely(!n_secs)) {
 93			s = hpfs_search_hotfix_map(inode->i_sb, s);
 94			n_secs = 1;
 95		}
 96		map_bh(bh_result, inode->i_sb, s);
 97		bh_result->b_size = n_secs << 9;
 98		goto ret_0;
 99	}
100	if (!create) goto ret_0;
101	if (iblock<<9 != hpfs_i(inode)->mmu_private) {
102		BUG();
103		r = -EIO;
104		goto ret_r;
105	}
106	if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) {
107		hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1);
108		r = -ENOSPC;
109		goto ret_r;
110	}
111	inode->i_blocks++;
112	hpfs_i(inode)->mmu_private += 512;
113	set_buffer_new(bh_result);
114	map_bh(bh_result, inode->i_sb, hpfs_search_hotfix_map(inode->i_sb, s));
115	ret_0:
116	r = 0;
117	ret_r:
118	hpfs_unlock(inode->i_sb);
119	return r;
120}
121
122static int hpfs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
123		unsigned flags, struct iomap *iomap, struct iomap *srcmap)
124{
125	struct super_block *sb = inode->i_sb;
126	unsigned int blkbits = inode->i_blkbits;
127	unsigned int n_secs;
128	secno s;
129
130	if (WARN_ON_ONCE(flags & (IOMAP_WRITE | IOMAP_ZERO)))
131		return -EINVAL;
132
133	iomap->bdev = inode->i_sb->s_bdev;
134	iomap->offset = offset;
135
136	hpfs_lock(sb);
137	s = hpfs_bmap(inode, offset >> blkbits, &n_secs);
138	if (s) {
139		n_secs = hpfs_search_hotfix_map_for_range(sb, s,
140				min_t(loff_t, n_secs, length));
141		if (unlikely(!n_secs)) {
142			s = hpfs_search_hotfix_map(sb, s);
143			n_secs = 1;
144		}
145		iomap->type = IOMAP_MAPPED;
146		iomap->flags = IOMAP_F_MERGED;
147		iomap->addr = (u64)s << blkbits;
148		iomap->length = (u64)n_secs << blkbits;
149	} else {
150		iomap->type = IOMAP_HOLE;
151		iomap->addr = IOMAP_NULL_ADDR;
152		iomap->length = 1 << blkbits;
153	}
154
155	hpfs_unlock(sb);
156	return 0;
157}
158
159static const struct iomap_ops hpfs_iomap_ops = {
160	.iomap_begin		= hpfs_iomap_begin,
161};
162
163static int hpfs_read_folio(struct file *file, struct folio *folio)
164{
165	return mpage_read_folio(folio, hpfs_get_block);
166}
167
168static void hpfs_readahead(struct readahead_control *rac)
169{
170	mpage_readahead(rac, hpfs_get_block);
171}
172
173static int hpfs_writepages(struct address_space *mapping,
174			   struct writeback_control *wbc)
175{
176	return mpage_writepages(mapping, wbc, hpfs_get_block);
177}
178
179static void hpfs_write_failed(struct address_space *mapping, loff_t to)
180{
181	struct inode *inode = mapping->host;
182
183	hpfs_lock(inode->i_sb);
184
185	if (to > inode->i_size) {
186		truncate_pagecache(inode, inode->i_size);
187		hpfs_truncate(inode);
188	}
189
190	hpfs_unlock(inode->i_sb);
191}
192
193static int hpfs_write_begin(const struct kiocb *iocb,
194			    struct address_space *mapping,
195			    loff_t pos, unsigned len,
196			    struct folio **foliop, void **fsdata)
197{
198	int ret;
199
200	ret = cont_write_begin(iocb, mapping, pos, len, foliop, fsdata,
201				hpfs_get_block,
202				&hpfs_i(mapping->host)->mmu_private);
203	if (unlikely(ret))
204		hpfs_write_failed(mapping, pos + len);
205
206	return ret;
207}
208
209static int hpfs_write_end(const struct kiocb *iocb,
210			  struct address_space *mapping,
211			  loff_t pos, unsigned len, unsigned copied,
212			  struct folio *folio, void *fsdata)
213{
214	struct inode *inode = mapping->host;
215	int err;
216	err = generic_write_end(iocb, mapping, pos, len, copied, folio, fsdata);
217	if (err < len)
218		hpfs_write_failed(mapping, pos + len);
219	if (!(err < 0)) {
220		/* make sure we write it on close, if not earlier */
221		hpfs_lock(inode->i_sb);
222		hpfs_i(inode)->i_dirty = 1;
223		hpfs_unlock(inode->i_sb);
224	}
225	return err;
226}
227
228static sector_t _hpfs_bmap(struct address_space *mapping, sector_t block)
229{
230	return generic_block_bmap(mapping, block, hpfs_get_block);
231}
232
233static int hpfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len)
234{
235	int ret;
236
237	inode_lock(inode);
238	len = min_t(u64, len, i_size_read(inode));
239	ret = iomap_fiemap(inode, fieinfo, start, len, &hpfs_iomap_ops);
240	inode_unlock(inode);
241
242	return ret;
243}
244
245const struct address_space_operations hpfs_aops = {
246	.dirty_folio	= block_dirty_folio,
247	.invalidate_folio = block_invalidate_folio,
248	.read_folio = hpfs_read_folio,
249	.readahead = hpfs_readahead,
250	.writepages = hpfs_writepages,
251	.write_begin = hpfs_write_begin,
252	.write_end = hpfs_write_end,
253	.bmap = _hpfs_bmap,
254	.migrate_folio = buffer_migrate_folio,
255};
256
257const struct file_operations hpfs_file_ops =
258{
259	.llseek		= generic_file_llseek,
260	.read_iter	= generic_file_read_iter,
261	.write_iter	= generic_file_write_iter,
262	.mmap_prepare	= generic_file_mmap_prepare,
263	.release	= hpfs_file_release,
264	.fsync		= hpfs_file_fsync,
265	.splice_read	= filemap_splice_read,
266	.unlocked_ioctl	= hpfs_ioctl,
267	.compat_ioctl	= compat_ptr_ioctl,
268};
269
270const struct inode_operations hpfs_file_iops =
271{
272	.setattr	= hpfs_setattr,
273	.fiemap		= hpfs_fiemap,
274};