file.c

  1/*
  2 * JFFS2 -- Journalling Flash File System, Version 2.
  3 *
  4 * Copyright © 2001-2007 Red Hat, Inc.
  5 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
  6 *
  7 * Created by David Woodhouse <dwmw2@infradead.org>
  8 *
  9 * For licensing information, see the file 'LICENCE' in this directory.
 10 *
 11 */
 12
 13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 14
 15#include <linux/kernel.h>
 16#include <linux/fs.h>
 17#include <linux/time.h>
 18#include <linux/pagemap.h>
 19#include <linux/highmem.h>
 20#include <linux/crc32.h>
 21#include <linux/jffs2.h>
 22#include "nodelist.h"
 23
 24static int jffs2_write_end(const struct kiocb *iocb,
 25			   struct address_space *mapping,
 26			   loff_t pos, unsigned len, unsigned copied,
 27			   struct folio *folio, void *fsdata);
 28static int jffs2_write_begin(const struct kiocb *iocb,
 29			     struct address_space *mapping,
 30			     loff_t pos, unsigned len,
 31			     struct folio **foliop, void **fsdata);
 32static int jffs2_read_folio(struct file *filp, struct folio *folio);
 33
 34int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 35{
 36	struct inode *inode = filp->f_mapping->host;
 37	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 38	int ret;
 39
 40	ret = file_write_and_wait_range(filp, start, end);
 41	if (ret)
 42		return ret;
 43
 44	inode_lock(inode);
 45	/* Trigger GC to flush any pending writes for this inode */
 46	jffs2_flush_wbuf_gc(c, inode->i_ino);
 47	inode_unlock(inode);
 48
 49	return 0;
 50}
 51
 52const struct file_operations jffs2_file_operations =
 53{
 54	.llseek =	generic_file_llseek,
 55	.open =		generic_file_open,
 56 	.read_iter =	generic_file_read_iter,
 57 	.write_iter =	generic_file_write_iter,
 58	.unlocked_ioctl=jffs2_ioctl,
 59	.mmap_prepare =	generic_file_readonly_mmap_prepare,
 60	.fsync =	jffs2_fsync,
 61	.splice_read =	filemap_splice_read,
 62	.splice_write = iter_file_splice_write,
 63};
 64
 65/* jffs2_file_inode_operations */
 66
 67const struct inode_operations jffs2_file_inode_operations =
 68{
 69	.get_inode_acl =	jffs2_get_acl,
 70	.set_acl =	jffs2_set_acl,
 71	.setattr =	jffs2_setattr,
 72	.listxattr =	jffs2_listxattr,
 73};
 74
 75const struct address_space_operations jffs2_file_address_operations =
 76{
 77	.read_folio =	jffs2_read_folio,
 78	.write_begin =	jffs2_write_begin,
 79	.write_end =	jffs2_write_end,
 80};
 81
 82static int jffs2_do_readpage_nolock(struct inode *inode, struct folio *folio)
 83{
 84	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 85	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 86	unsigned char *kaddr;
 87	int ret;
 88
 89	jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
 90		  __func__, inode->i_ino, folio->index << PAGE_SHIFT);
 91
 92	BUG_ON(!folio_test_locked(folio));
 93
 94	kaddr = kmap_local_folio(folio, 0);
 95	ret = jffs2_read_inode_range(c, f, kaddr, folio->index << PAGE_SHIFT,
 96				     PAGE_SIZE);
 97	kunmap_local(kaddr);
 98
 99	if (!ret)
100		folio_mark_uptodate(folio);
101
102	flush_dcache_folio(folio);
103
104	jffs2_dbg(2, "readpage finished\n");
105	return ret;
106}
107
108int __jffs2_read_folio(struct file *file, struct folio *folio)
109{
110	int ret = jffs2_do_readpage_nolock(folio->mapping->host, folio);
111	folio_unlock(folio);
112	return ret;
113}
114
115static int jffs2_read_folio(struct file *file, struct folio *folio)
116{
117	struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
118	int ret;
119
120	mutex_lock(&f->sem);
121	ret = __jffs2_read_folio(file, folio);
122	mutex_unlock(&f->sem);
123	return ret;
124}
125
126static int jffs2_write_begin(const struct kiocb *iocb,
127			     struct address_space *mapping,
128			     loff_t pos, unsigned len,
129			     struct folio **foliop, void **fsdata)
130{
131	struct folio *folio;
132	struct inode *inode = mapping->host;
133	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
134	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
135	pgoff_t index = pos >> PAGE_SHIFT;
136	int ret = 0;
137
138	jffs2_dbg(1, "%s()\n", __func__);
139
140	if (pos > inode->i_size) {
141		/* Make new hole frag from old EOF to new position */
142		struct jffs2_raw_inode ri;
143		struct jffs2_full_dnode *fn;
144		uint32_t alloc_len;
145
146		jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
147			  (unsigned int)inode->i_size, (uint32_t)pos);
148
149		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
150					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
151		if (ret)
152			goto out_err;
153
154		mutex_lock(&f->sem);
155		memset(&ri, 0, sizeof(ri));
156
157		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
158		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
159		ri.totlen = cpu_to_je32(sizeof(ri));
160		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
161
162		ri.ino = cpu_to_je32(f->inocache->ino);
163		ri.version = cpu_to_je32(++f->highest_version);
164		ri.mode = cpu_to_jemode(inode->i_mode);
165		ri.uid = cpu_to_je16(i_uid_read(inode));
166		ri.gid = cpu_to_je16(i_gid_read(inode));
167		ri.isize = cpu_to_je32((uint32_t)pos);
168		ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
169		ri.offset = cpu_to_je32(inode->i_size);
170		ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
171		ri.csize = cpu_to_je32(0);
172		ri.compr = JFFS2_COMPR_ZERO;
173		ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
174		ri.data_crc = cpu_to_je32(0);
175
176		fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
177
178		if (IS_ERR(fn)) {
179			ret = PTR_ERR(fn);
180			jffs2_complete_reservation(c);
181			mutex_unlock(&f->sem);
182			goto out_err;
183		}
184		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
185		if (f->metadata) {
186			jffs2_mark_node_obsolete(c, f->metadata->raw);
187			jffs2_free_full_dnode(f->metadata);
188			f->metadata = NULL;
189		}
190		if (ret) {
191			jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
192				  ret);
193			jffs2_mark_node_obsolete(c, fn->raw);
194			jffs2_free_full_dnode(fn);
195			jffs2_complete_reservation(c);
196			mutex_unlock(&f->sem);
197			goto out_err;
198		}
199		jffs2_complete_reservation(c);
200		inode->i_size = pos;
201		mutex_unlock(&f->sem);
202	}
203
204	/*
205	 * While getting a page and reading data in, lock c->alloc_sem until
206	 * the page is Uptodate. Otherwise GC task may attempt to read the same
207	 * page in read_cache_page(), which causes a deadlock.
208	 */
209	mutex_lock(&c->alloc_sem);
210	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
211			mapping_gfp_mask(mapping));
212	if (IS_ERR(folio)) {
213		ret = PTR_ERR(folio);
214		goto release_sem;
215	}
216	*foliop = folio;
217
218	/*
219	 * Read in the folio if it wasn't already present. Cannot optimize away
220	 * the whole folio write case until jffs2_write_end can handle the
221	 * case of a short-copy.
222	 */
223	if (!folio_test_uptodate(folio)) {
224		mutex_lock(&f->sem);
225		ret = jffs2_do_readpage_nolock(inode, folio);
226		mutex_unlock(&f->sem);
227		if (ret) {
228			folio_unlock(folio);
229			folio_put(folio);
230			goto release_sem;
231		}
232	}
233	jffs2_dbg(1, "end write_begin(). folio->flags %lx\n", folio->flags.f);
234
235release_sem:
236	mutex_unlock(&c->alloc_sem);
237out_err:
238	return ret;
239}
240
241static int jffs2_write_end(const struct kiocb *iocb,
242			   struct address_space *mapping,
243			   loff_t pos, unsigned len, unsigned copied,
244			   struct folio *folio, void *fsdata)
245{
246	/* Actually commit the write from the page cache page we're looking at.
247	 * For now, we write the full page out each time. It sucks, but it's simple
248	 */
249	struct inode *inode = mapping->host;
250	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
251	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
252	struct jffs2_raw_inode *ri;
253	unsigned start = pos & (PAGE_SIZE - 1);
254	unsigned end = start + copied;
255	unsigned aligned_start = start & ~3;
256	int ret = 0;
257	uint32_t writtenlen = 0;
258	void *buf;
259
260	jffs2_dbg(1, "%s(): ino #%lu, page at 0x%llx, range %d-%d, flags %lx\n",
261		  __func__, inode->i_ino, folio_pos(folio),
262		  start, end, folio->flags.f);
263
264	/* We need to avoid deadlock with page_cache_read() in
265	   jffs2_garbage_collect_pass(). So the folio must be
266	   up to date to prevent page_cache_read() from trying
267	   to re-lock it. */
268	BUG_ON(!folio_test_uptodate(folio));
269
270	if (end == PAGE_SIZE) {
271		/* When writing out the end of a page, write out the
272		   _whole_ page. This helps to reduce the number of
273		   nodes in files which have many short writes, like
274		   syslog files. */
275		aligned_start = 0;
276	}
277
278	ri = jffs2_alloc_raw_inode();
279
280	if (!ri) {
281		jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
282			  __func__);
283		folio_unlock(folio);
284		folio_put(folio);
285		return -ENOMEM;
286	}
287
288	/* Set the fields that the generic jffs2_write_inode_range() code can't find */
289	ri->ino = cpu_to_je32(inode->i_ino);
290	ri->mode = cpu_to_jemode(inode->i_mode);
291	ri->uid = cpu_to_je16(i_uid_read(inode));
292	ri->gid = cpu_to_je16(i_gid_read(inode));
293	ri->isize = cpu_to_je32((uint32_t)inode->i_size);
294	ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
295
296	buf = kmap_local_folio(folio, aligned_start);
297	ret = jffs2_write_inode_range(c, f, ri, buf,
298				      folio_pos(folio) + aligned_start,
299				      end - aligned_start, &writtenlen);
300	kunmap_local(buf);
301
302	if (ret)
303		mapping_set_error(mapping, ret);
304
305	/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
306	writtenlen -= min(writtenlen, (start - aligned_start));
307
308	if (writtenlen) {
309		if (inode->i_size < pos + writtenlen) {
310			inode->i_size = pos + writtenlen;
311			inode->i_blocks = (inode->i_size + 511) >> 9;
312
313			inode_set_mtime_to_ts(inode,
314					      inode_set_ctime_to_ts(inode, ITIME(je32_to_cpu(ri->ctime))));
315		}
316	}
317
318	jffs2_free_raw_inode(ri);
319
320	if (start+writtenlen < end) {
321		/* generic_file_write has written more to the page cache than we've
322		   actually written to the medium. Mark the page !Uptodate so that
323		   it gets reread */
324		jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
325			__func__);
326		folio_clear_uptodate(folio);
327	}
328
329	jffs2_dbg(1, "%s() returning %d\n",
330		  __func__, writtenlen > 0 ? writtenlen : ret);
331	folio_unlock(folio);
332	folio_put(folio);
333	return writtenlen > 0 ? writtenlen : ret;
334}