ia64/linux-2.6.18-xen.hg

view fs/jffs2/file.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright (C) 2001-2003 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 * $Id: file.c,v 1.104 2005/10/18 23:29:35 tpoynor Exp $
11 *
12 */
14 #include <linux/kernel.h>
15 #include <linux/slab.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"
24 static int jffs2_commit_write (struct file *filp, struct page *pg,
25 unsigned start, unsigned end);
26 static int jffs2_prepare_write (struct file *filp, struct page *pg,
27 unsigned start, unsigned end);
28 static int jffs2_readpage (struct file *filp, struct page *pg);
30 int 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);
35 /* Trigger GC to flush any pending writes for this inode */
36 jffs2_flush_wbuf_gc(c, inode->i_ino);
38 return 0;
39 }
41 const struct file_operations jffs2_file_operations =
42 {
43 .llseek = generic_file_llseek,
44 .open = generic_file_open,
45 .read = generic_file_read,
46 .write = generic_file_write,
47 .ioctl = jffs2_ioctl,
48 .mmap = generic_file_readonly_mmap,
49 .fsync = jffs2_fsync,
50 .sendfile = generic_file_sendfile
51 };
53 /* jffs2_file_inode_operations */
55 struct inode_operations jffs2_file_inode_operations =
56 {
57 .permission = jffs2_permission,
58 .setattr = jffs2_setattr,
59 .setxattr = jffs2_setxattr,
60 .getxattr = jffs2_getxattr,
61 .listxattr = jffs2_listxattr,
62 .removexattr = jffs2_removexattr
63 };
65 const struct address_space_operations jffs2_file_address_operations =
66 {
67 .readpage = jffs2_readpage,
68 .prepare_write =jffs2_prepare_write,
69 .commit_write = jffs2_commit_write
70 };
72 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
73 {
74 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
75 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
76 unsigned char *pg_buf;
77 int ret;
79 D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));
81 BUG_ON(!PageLocked(pg));
83 pg_buf = kmap(pg);
84 /* FIXME: Can kmap fail? */
86 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
88 if (ret) {
89 ClearPageUptodate(pg);
90 SetPageError(pg);
91 } else {
92 SetPageUptodate(pg);
93 ClearPageError(pg);
94 }
96 flush_dcache_page(pg);
97 kunmap(pg);
99 D2(printk(KERN_DEBUG "readpage finished\n"));
100 return 0;
101 }
103 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
104 {
105 int ret = jffs2_do_readpage_nolock(inode, pg);
106 unlock_page(pg);
107 return ret;
108 }
111 static int jffs2_readpage (struct file *filp, struct page *pg)
112 {
113 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
114 int ret;
116 down(&f->sem);
117 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
118 up(&f->sem);
119 return ret;
120 }
122 static int jffs2_prepare_write (struct file *filp, struct page *pg,
123 unsigned start, unsigned end)
124 {
125 struct inode *inode = pg->mapping->host;
126 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
127 uint32_t pageofs = pg->index << PAGE_CACHE_SHIFT;
128 int ret = 0;
130 D1(printk(KERN_DEBUG "jffs2_prepare_write()\n"));
132 if (pageofs > inode->i_size) {
133 /* Make new hole frag from old EOF to new page */
134 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
135 struct jffs2_raw_inode ri;
136 struct jffs2_full_dnode *fn;
137 uint32_t alloc_len;
139 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
140 (unsigned int)inode->i_size, pageofs));
142 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
143 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
144 if (ret)
145 return ret;
147 down(&f->sem);
148 memset(&ri, 0, sizeof(ri));
150 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
151 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
152 ri.totlen = cpu_to_je32(sizeof(ri));
153 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
155 ri.ino = cpu_to_je32(f->inocache->ino);
156 ri.version = cpu_to_je32(++f->highest_version);
157 ri.mode = cpu_to_jemode(inode->i_mode);
158 ri.uid = cpu_to_je16(inode->i_uid);
159 ri.gid = cpu_to_je16(inode->i_gid);
160 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
161 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
162 ri.offset = cpu_to_je32(inode->i_size);
163 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
164 ri.csize = cpu_to_je32(0);
165 ri.compr = JFFS2_COMPR_ZERO;
166 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
167 ri.data_crc = cpu_to_je32(0);
169 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
171 if (IS_ERR(fn)) {
172 ret = PTR_ERR(fn);
173 jffs2_complete_reservation(c);
174 up(&f->sem);
175 return ret;
176 }
177 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
178 if (f->metadata) {
179 jffs2_mark_node_obsolete(c, f->metadata->raw);
180 jffs2_free_full_dnode(f->metadata);
181 f->metadata = NULL;
182 }
183 if (ret) {
184 D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
185 jffs2_mark_node_obsolete(c, fn->raw);
186 jffs2_free_full_dnode(fn);
187 jffs2_complete_reservation(c);
188 up(&f->sem);
189 return ret;
190 }
191 jffs2_complete_reservation(c);
192 inode->i_size = pageofs;
193 up(&f->sem);
194 }
196 /* Read in the page if it wasn't already present, unless it's a whole page */
197 if (!PageUptodate(pg) && (start || end < PAGE_CACHE_SIZE)) {
198 down(&f->sem);
199 ret = jffs2_do_readpage_nolock(inode, pg);
200 up(&f->sem);
201 }
202 D1(printk(KERN_DEBUG "end prepare_write(). pg->flags %lx\n", pg->flags));
203 return ret;
204 }
206 static int jffs2_commit_write (struct file *filp, struct page *pg,
207 unsigned start, unsigned end)
208 {
209 /* Actually commit the write from the page cache page we're looking at.
210 * For now, we write the full page out each time. It sucks, but it's simple
211 */
212 struct inode *inode = pg->mapping->host;
213 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
214 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
215 struct jffs2_raw_inode *ri;
216 unsigned aligned_start = start & ~3;
217 int ret = 0;
218 uint32_t writtenlen = 0;
220 D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
221 inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
223 if (end == PAGE_CACHE_SIZE) {
224 if (!start) {
225 /* We need to avoid deadlock with page_cache_read() in
226 jffs2_garbage_collect_pass(). So we have to mark the
227 page up to date, to prevent page_cache_read() from
228 trying to re-lock it. */
229 SetPageUptodate(pg);
230 } else {
231 /* When writing out the end of a page, write out the
232 _whole_ page. This helps to reduce the number of
233 nodes in files which have many short writes, like
234 syslog files. */
235 start = aligned_start = 0;
236 }
237 }
239 ri = jffs2_alloc_raw_inode();
241 if (!ri) {
242 D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
243 return -ENOMEM;
244 }
246 /* Set the fields that the generic jffs2_write_inode_range() code can't find */
247 ri->ino = cpu_to_je32(inode->i_ino);
248 ri->mode = cpu_to_jemode(inode->i_mode);
249 ri->uid = cpu_to_je16(inode->i_uid);
250 ri->gid = cpu_to_je16(inode->i_gid);
251 ri->isize = cpu_to_je32((uint32_t)inode->i_size);
252 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
254 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
255 hurt to do it again. The alternative is ifdefs, which are ugly. */
256 kmap(pg);
258 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
259 (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
260 end - aligned_start, &writtenlen);
262 kunmap(pg);
264 if (ret) {
265 /* There was an error writing. */
266 SetPageError(pg);
267 }
269 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
270 if (writtenlen < (start&3))
271 writtenlen = 0;
272 else
273 writtenlen -= (start&3);
275 if (writtenlen) {
276 if (inode->i_size < (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen) {
277 inode->i_size = (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen;
278 inode->i_blocks = (inode->i_size + 511) >> 9;
280 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
281 }
282 }
284 jffs2_free_raw_inode(ri);
286 if (start+writtenlen < end) {
287 /* generic_file_write has written more to the page cache than we've
288 actually written to the medium. Mark the page !Uptodate so that
289 it gets reread */
290 D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
291 SetPageError(pg);
292 ClearPageUptodate(pg);
293 }
295 D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",start+writtenlen==end?0:ret));
296 return start+writtenlen==end?0:ret;
297 }