Root/fs/jffs2/file.c

1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 Red Hat, Inc.
5 *
6 * Created by David Woodhouse <dwmw2@infradead.org>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 */
11
12#include <linux/kernel.h>
13#include <linux/slab.h>
14#include <linux/fs.h>
15#include <linux/time.h>
16#include <linux/pagemap.h>
17#include <linux/highmem.h>
18#include <linux/crc32.h>
19#include <linux/jffs2.h>
20#include "nodelist.h"
21
22static int jffs2_write_end(struct file *filp, struct address_space *mapping,
23            loff_t pos, unsigned len, unsigned copied,
24            struct page *pg, void *fsdata);
25static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
26            loff_t pos, unsigned len, unsigned flags,
27            struct page **pagep, void **fsdata);
28static int jffs2_readpage (struct file *filp, struct page *pg);
29
30int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync)
31{
32    struct inode *inode = dentry->d_inode;
33    struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
34
35    /* Trigger GC to flush any pending writes for this inode */
36    jffs2_flush_wbuf_gc(c, inode->i_ino);
37
38    return 0;
39}
40
41const struct file_operations jffs2_file_operations =
42{
43    .llseek = generic_file_llseek,
44    .open = generic_file_open,
45     .read = do_sync_read,
46     .aio_read = generic_file_aio_read,
47     .write = do_sync_write,
48     .aio_write = generic_file_aio_write,
49    .unlocked_ioctl=jffs2_ioctl,
50    .mmap = generic_file_readonly_mmap,
51    .fsync = jffs2_fsync,
52    .splice_read = generic_file_splice_read,
53};
54
55/* jffs2_file_inode_operations */
56
57const struct inode_operations jffs2_file_inode_operations =
58{
59    .permission = jffs2_permission,
60    .setattr = jffs2_setattr,
61    .setxattr = jffs2_setxattr,
62    .getxattr = jffs2_getxattr,
63    .listxattr = jffs2_listxattr,
64    .removexattr = jffs2_removexattr
65};
66
67const struct address_space_operations jffs2_file_address_operations =
68{
69    .readpage = jffs2_readpage,
70    .write_begin = jffs2_write_begin,
71    .write_end = jffs2_write_end,
72};
73
74static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
75{
76    struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
77    struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
78    unsigned char *pg_buf;
79    int ret;
80
81    D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));
82
83    BUG_ON(!PageLocked(pg));
84
85    pg_buf = kmap(pg);
86    /* FIXME: Can kmap fail? */
87
88    ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
89
90    if (ret) {
91        ClearPageUptodate(pg);
92        SetPageError(pg);
93    } else {
94        SetPageUptodate(pg);
95        ClearPageError(pg);
96    }
97
98    flush_dcache_page(pg);
99    kunmap(pg);
100
101    D2(printk(KERN_DEBUG "readpage finished\n"));
102    return ret;
103}
104
105int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
106{
107    int ret = jffs2_do_readpage_nolock(inode, pg);
108    unlock_page(pg);
109    return ret;
110}
111
112
113static int jffs2_readpage (struct file *filp, struct page *pg)
114{
115    struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
116    int ret;
117
118    mutex_lock(&f->sem);
119    ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
120    mutex_unlock(&f->sem);
121    return ret;
122}
123
124static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
125            loff_t pos, unsigned len, unsigned flags,
126            struct page **pagep, void **fsdata)
127{
128    struct page *pg;
129    struct inode *inode = mapping->host;
130    struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
131    pgoff_t index = pos >> PAGE_CACHE_SHIFT;
132    uint32_t pageofs = index << PAGE_CACHE_SHIFT;
133    int ret = 0;
134
135    pg = grab_cache_page_write_begin(mapping, index, flags);
136    if (!pg)
137        return -ENOMEM;
138    *pagep = pg;
139
140    D1(printk(KERN_DEBUG "jffs2_write_begin()\n"));
141
142    if (pageofs > inode->i_size) {
143        /* Make new hole frag from old EOF to new page */
144        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
145        struct jffs2_raw_inode ri;
146        struct jffs2_full_dnode *fn;
147        uint32_t alloc_len;
148
149        D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
150              (unsigned int)inode->i_size, pageofs));
151
152        ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
153                      ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
154        if (ret)
155            goto out_page;
156
157        mutex_lock(&f->sem);
158        memset(&ri, 0, sizeof(ri));
159
160        ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
161        ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
162        ri.totlen = cpu_to_je32(sizeof(ri));
163        ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
164
165        ri.ino = cpu_to_je32(f->inocache->ino);
166        ri.version = cpu_to_je32(++f->highest_version);
167        ri.mode = cpu_to_jemode(inode->i_mode);
168        ri.uid = cpu_to_je16(inode->i_uid);
169        ri.gid = cpu_to_je16(inode->i_gid);
170        ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
171        ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
172        ri.offset = cpu_to_je32(inode->i_size);
173        ri.dsize = cpu_to_je32(pageofs - inode->i_size);
174        ri.csize = cpu_to_je32(0);
175        ri.compr = JFFS2_COMPR_ZERO;
176        ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
177        ri.data_crc = cpu_to_je32(0);
178
179        fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
180
181        if (IS_ERR(fn)) {
182            ret = PTR_ERR(fn);
183            jffs2_complete_reservation(c);
184            mutex_unlock(&f->sem);
185            goto out_page;
186        }
187        ret = jffs2_add_full_dnode_to_inode(c, f, fn);
188        if (f->metadata) {
189            jffs2_mark_node_obsolete(c, f->metadata->raw);
190            jffs2_free_full_dnode(f->metadata);
191            f->metadata = NULL;
192        }
193        if (ret) {
194            D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", ret));
195            jffs2_mark_node_obsolete(c, fn->raw);
196            jffs2_free_full_dnode(fn);
197            jffs2_complete_reservation(c);
198            mutex_unlock(&f->sem);
199            goto out_page;
200        }
201        jffs2_complete_reservation(c);
202        inode->i_size = pageofs;
203        mutex_unlock(&f->sem);
204    }
205
206    /*
207     * Read in the page if it wasn't already present. Cannot optimize away
208     * the whole page write case until jffs2_write_end can handle the
209     * case of a short-copy.
210     */
211    if (!PageUptodate(pg)) {
212        mutex_lock(&f->sem);
213        ret = jffs2_do_readpage_nolock(inode, pg);
214        mutex_unlock(&f->sem);
215        if (ret)
216            goto out_page;
217    }
218    D1(printk(KERN_DEBUG "end write_begin(). pg->flags %lx\n", pg->flags));
219    return ret;
220
221out_page:
222    unlock_page(pg);
223    page_cache_release(pg);
224    return ret;
225}
226
227static int jffs2_write_end(struct file *filp, struct address_space *mapping,
228            loff_t pos, unsigned len, unsigned copied,
229            struct page *pg, void *fsdata)
230{
231    /* Actually commit the write from the page cache page we're looking at.
232     * For now, we write the full page out each time. It sucks, but it's simple
233     */
234    struct inode *inode = mapping->host;
235    struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
236    struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
237    struct jffs2_raw_inode *ri;
238    unsigned start = pos & (PAGE_CACHE_SIZE - 1);
239    unsigned end = start + copied;
240    unsigned aligned_start = start & ~3;
241    int ret = 0;
242    uint32_t writtenlen = 0;
243
244    D1(printk(KERN_DEBUG "jffs2_write_end(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
245          inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
246
247    /* We need to avoid deadlock with page_cache_read() in
248       jffs2_garbage_collect_pass(). So the page must be
249       up to date to prevent page_cache_read() from trying
250       to re-lock it. */
251    BUG_ON(!PageUptodate(pg));
252
253    if (end == PAGE_CACHE_SIZE) {
254        /* When writing out the end of a page, write out the
255           _whole_ page. This helps to reduce the number of
256           nodes in files which have many short writes, like
257           syslog files. */
258        aligned_start = 0;
259    }
260
261    ri = jffs2_alloc_raw_inode();
262
263    if (!ri) {
264        D1(printk(KERN_DEBUG "jffs2_write_end(): Allocation of raw inode failed\n"));
265        unlock_page(pg);
266        page_cache_release(pg);
267        return -ENOMEM;
268    }
269
270    /* Set the fields that the generic jffs2_write_inode_range() code can't find */
271    ri->ino = cpu_to_je32(inode->i_ino);
272    ri->mode = cpu_to_jemode(inode->i_mode);
273    ri->uid = cpu_to_je16(inode->i_uid);
274    ri->gid = cpu_to_je16(inode->i_gid);
275    ri->isize = cpu_to_je32((uint32_t)inode->i_size);
276    ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
277
278    /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
279       hurt to do it again. The alternative is ifdefs, which are ugly. */
280    kmap(pg);
281
282    ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
283                      (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
284                      end - aligned_start, &writtenlen);
285
286    kunmap(pg);
287
288    if (ret) {
289        /* There was an error writing. */
290        SetPageError(pg);
291    }
292
293    /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
294    writtenlen -= min(writtenlen, (start - aligned_start));
295
296    if (writtenlen) {
297        if (inode->i_size < pos + writtenlen) {
298            inode->i_size = pos + writtenlen;
299            inode->i_blocks = (inode->i_size + 511) >> 9;
300
301            inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
302        }
303    }
304
305    jffs2_free_raw_inode(ri);
306
307    if (start+writtenlen < end) {
308        /* generic_file_write has written more to the page cache than we've
309           actually written to the medium. Mark the page !Uptodate so that
310           it gets reread */
311        D1(printk(KERN_DEBUG "jffs2_write_end(): Not all bytes written. Marking page !uptodate\n"));
312        SetPageError(pg);
313        ClearPageUptodate(pg);
314    }
315
316    D1(printk(KERN_DEBUG "jffs2_write_end() returning %d\n",
317                    writtenlen > 0 ? writtenlen : ret));
318    unlock_page(pg);
319    page_cache_release(pg);
320    return writtenlen > 0 ? writtenlen : ret;
321}
322

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