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-rw-r--r--fs/ramfs/Makefile4
-rw-r--r--fs/ramfs/file-mmu.c57
-rw-r--r--fs/ramfs/file-nommu.c292
-rw-r--r--fs/ramfs/inode.c22
-rw-r--r--fs/ramfs/internal.h15
-rw-r--r--include/linux/ramfs.h10
6 files changed, 378 insertions, 22 deletions
diff --git a/fs/ramfs/Makefile b/fs/ramfs/Makefile
index f096f3007091..5a0236e02ee1 100644
--- a/fs/ramfs/Makefile
+++ b/fs/ramfs/Makefile
@@ -4,4 +4,6 @@
4 4
5obj-$(CONFIG_RAMFS) += ramfs.o 5obj-$(CONFIG_RAMFS) += ramfs.o
6 6
7ramfs-objs := inode.o 7file-mmu-y := file-nommu.o
8file-mmu-$(CONFIG_MMU) := file-mmu.o
9ramfs-objs += inode.o $(file-mmu-y)
diff --git a/fs/ramfs/file-mmu.c b/fs/ramfs/file-mmu.c
new file mode 100644
index 000000000000..2115383dcc8d
--- /dev/null
+++ b/fs/ramfs/file-mmu.c
@@ -0,0 +1,57 @@
1/* file-mmu.c: ramfs MMU-based file operations
2 *
3 * Resizable simple ram filesystem for Linux.
4 *
5 * Copyright (C) 2000 Linus Torvalds.
6 * 2000 Transmeta Corp.
7 *
8 * Usage limits added by David Gibson, Linuxcare Australia.
9 * This file is released under the GPL.
10 */
11
12/*
13 * NOTE! This filesystem is probably most useful
14 * not as a real filesystem, but as an example of
15 * how virtual filesystems can be written.
16 *
17 * It doesn't get much simpler than this. Consider
18 * that this file implements the full semantics of
19 * a POSIX-compliant read-write filesystem.
20 *
21 * Note in particular how the filesystem does not
22 * need to implement any data structures of its own
23 * to keep track of the virtual data: using the VFS
24 * caches is sufficient.
25 */
26
27#include <linux/module.h>
28#include <linux/fs.h>
29#include <linux/pagemap.h>
30#include <linux/highmem.h>
31#include <linux/init.h>
32#include <linux/string.h>
33#include <linux/smp_lock.h>
34#include <linux/backing-dev.h>
35#include <linux/ramfs.h>
36
37#include <asm/uaccess.h>
38#include "internal.h"
39
40struct address_space_operations ramfs_aops = {
41 .readpage = simple_readpage,
42 .prepare_write = simple_prepare_write,
43 .commit_write = simple_commit_write
44};
45
46struct file_operations ramfs_file_operations = {
47 .read = generic_file_read,
48 .write = generic_file_write,
49 .mmap = generic_file_mmap,
50 .fsync = simple_sync_file,
51 .sendfile = generic_file_sendfile,
52 .llseek = generic_file_llseek,
53};
54
55struct inode_operations ramfs_file_inode_operations = {
56 .getattr = simple_getattr,
57};
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
new file mode 100644
index 000000000000..3f810acd0bfa
--- /dev/null
+++ b/fs/ramfs/file-nommu.c
@@ -0,0 +1,292 @@
1/* file-nommu.c: no-MMU version of ramfs
2 *
3 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/pagemap.h>
15#include <linux/highmem.h>
16#include <linux/init.h>
17#include <linux/string.h>
18#include <linux/smp_lock.h>
19#include <linux/backing-dev.h>
20#include <linux/ramfs.h>
21#include <linux/quotaops.h>
22#include <linux/pagevec.h>
23#include <linux/mman.h>
24
25#include <asm/uaccess.h>
26#include "internal.h"
27
28static int ramfs_nommu_setattr(struct dentry *, struct iattr *);
29
30struct address_space_operations ramfs_aops = {
31 .readpage = simple_readpage,
32 .prepare_write = simple_prepare_write,
33 .commit_write = simple_commit_write
34};
35
36struct file_operations ramfs_file_operations = {
37 .mmap = ramfs_nommu_mmap,
38 .get_unmapped_area = ramfs_nommu_get_unmapped_area,
39 .read = generic_file_read,
40 .write = generic_file_write,
41 .fsync = simple_sync_file,
42 .sendfile = generic_file_sendfile,
43 .llseek = generic_file_llseek,
44};
45
46struct inode_operations ramfs_file_inode_operations = {
47 .setattr = ramfs_nommu_setattr,
48 .getattr = simple_getattr,
49};
50
51/*****************************************************************************/
52/*
53 * add a contiguous set of pages into a ramfs inode when it's truncated from
54 * size 0 on the assumption that it's going to be used for an mmap of shared
55 * memory
56 */
57static int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
58{
59 struct pagevec lru_pvec;
60 unsigned long npages, xpages, loop, limit;
61 struct page *pages;
62 unsigned order;
63 void *data;
64 int ret;
65
66 /* make various checks */
67 order = get_order(newsize);
68 if (unlikely(order >= MAX_ORDER))
69 goto too_big;
70
71 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
72 if (limit != RLIM_INFINITY && newsize > limit)
73 goto fsize_exceeded;
74
75 if (newsize > inode->i_sb->s_maxbytes)
76 goto too_big;
77
78 i_size_write(inode, newsize);
79
80 /* allocate enough contiguous pages to be able to satisfy the
81 * request */
82 pages = alloc_pages(mapping_gfp_mask(inode->i_mapping), order);
83 if (!pages)
84 return -ENOMEM;
85
86 /* split the high-order page into an array of single pages */
87 xpages = 1UL << order;
88 npages = (newsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
89
90 for (loop = 0; loop < npages; loop++)
91 set_page_count(pages + loop, 1);
92
93 /* trim off any pages we don't actually require */
94 for (loop = npages; loop < xpages; loop++)
95 __free_page(pages + loop);
96
97 /* clear the memory we allocated */
98 newsize = PAGE_SIZE * npages;
99 data = page_address(pages);
100 memset(data, 0, newsize);
101
102 /* attach all the pages to the inode's address space */
103 pagevec_init(&lru_pvec, 0);
104 for (loop = 0; loop < npages; loop++) {
105 struct page *page = pages + loop;
106
107 ret = add_to_page_cache(page, inode->i_mapping, loop, GFP_KERNEL);
108 if (ret < 0)
109 goto add_error;
110
111 if (!pagevec_add(&lru_pvec, page))
112 __pagevec_lru_add(&lru_pvec);
113
114 unlock_page(page);
115 }
116
117 pagevec_lru_add(&lru_pvec);
118 return 0;
119
120 fsize_exceeded:
121 send_sig(SIGXFSZ, current, 0);
122 too_big:
123 return -EFBIG;
124
125 add_error:
126 page_cache_release(pages + loop);
127 for (loop++; loop < npages; loop++)
128 __free_page(pages + loop);
129 return ret;
130}
131
132/*****************************************************************************/
133/*
134 * check that file shrinkage doesn't leave any VMAs dangling in midair
135 */
136static int ramfs_nommu_check_mappings(struct inode *inode,
137 size_t newsize, size_t size)
138{
139 struct vm_area_struct *vma;
140 struct prio_tree_iter iter;
141
142 /* search for VMAs that fall within the dead zone */
143 vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
144 newsize >> PAGE_SHIFT,
145 (size + PAGE_SIZE - 1) >> PAGE_SHIFT
146 ) {
147 /* found one - only interested if it's shared out of the page
148 * cache */
149 if (vma->vm_flags & VM_SHARED)
150 return -ETXTBSY; /* not quite true, but near enough */
151 }
152
153 return 0;
154}
155
156/*****************************************************************************/
157/*
158 *
159 */
160static int ramfs_nommu_resize(struct inode *inode, loff_t newsize, loff_t size)
161{
162 int ret;
163
164 /* assume a truncate from zero size is going to be for the purposes of
165 * shared mmap */
166 if (size == 0) {
167 if (unlikely(newsize >> 32))
168 return -EFBIG;
169
170 return ramfs_nommu_expand_for_mapping(inode, newsize);
171 }
172
173 /* check that a decrease in size doesn't cut off any shared mappings */
174 if (newsize < size) {
175 ret = ramfs_nommu_check_mappings(inode, newsize, size);
176 if (ret < 0)
177 return ret;
178 }
179
180 ret = vmtruncate(inode, size);
181
182 return ret;
183}
184
185/*****************************************************************************/
186/*
187 * handle a change of attributes
188 * - we're specifically interested in a change of size
189 */
190static int ramfs_nommu_setattr(struct dentry *dentry, struct iattr *ia)
191{
192 struct inode *inode = dentry->d_inode;
193 unsigned int old_ia_valid = ia->ia_valid;
194 int ret = 0;
195
196 /* by providing our own setattr() method, we skip this quotaism */
197 if ((old_ia_valid & ATTR_UID && ia->ia_uid != inode->i_uid) ||
198 (old_ia_valid & ATTR_GID && ia->ia_gid != inode->i_gid))
199 ret = DQUOT_TRANSFER(inode, ia) ? -EDQUOT : 0;
200
201 /* pick out size-changing events */
202 if (ia->ia_valid & ATTR_SIZE) {
203 loff_t size = i_size_read(inode);
204 if (ia->ia_size != size) {
205 ret = ramfs_nommu_resize(inode, ia->ia_size, size);
206 if (ret < 0 || ia->ia_valid == ATTR_SIZE)
207 goto out;
208 } else {
209 /* we skipped the truncate but must still update
210 * timestamps
211 */
212 ia->ia_valid |= ATTR_MTIME|ATTR_CTIME;
213 }
214 }
215
216 ret = inode_setattr(inode, ia);
217 out:
218 ia->ia_valid = old_ia_valid;
219 return ret;
220}
221
222/*****************************************************************************/
223/*
224 * try to determine where a shared mapping can be made
225 * - we require that:
226 * - the pages to be mapped must exist
227 * - the pages be physically contiguous in sequence
228 */
229unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
230 unsigned long addr, unsigned long len,
231 unsigned long pgoff, unsigned long flags)
232{
233 unsigned long maxpages, lpages, nr, loop, ret;
234 struct inode *inode = file->f_dentry->d_inode;
235 struct page **pages = NULL, **ptr, *page;
236 loff_t isize;
237
238 if (!(flags & MAP_SHARED))
239 return addr;
240
241 /* the mapping mustn't extend beyond the EOF */
242 lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
243 isize = i_size_read(inode);
244
245 ret = -EINVAL;
246 maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
247 if (pgoff >= maxpages)
248 goto out;
249
250 if (maxpages - pgoff < lpages)
251 goto out;
252
253 /* gang-find the pages */
254 ret = -ENOMEM;
255 pages = kzalloc(lpages * sizeof(struct page *), GFP_KERNEL);
256 if (!pages)
257 goto out;
258
259 nr = find_get_pages(inode->i_mapping, pgoff, lpages, pages);
260 if (nr != lpages)
261 goto out; /* leave if some pages were missing */
262
263 /* check the pages for physical adjacency */
264 ptr = pages;
265 page = *ptr++;
266 page++;
267 for (loop = lpages; loop > 1; loop--)
268 if (*ptr++ != page++)
269 goto out;
270
271 /* okay - all conditions fulfilled */
272 ret = (unsigned long) page_address(pages[0]);
273
274 out:
275 if (pages) {
276 ptr = pages;
277 for (loop = lpages; loop > 0; loop--)
278 put_page(*ptr++);
279 kfree(pages);
280 }
281
282 return ret;
283}
284
285/*****************************************************************************/
286/*
287 * set up a mapping
288 */
289int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma)
290{
291 return 0;
292}
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index 0a88917605ae..c66bd5e4c05c 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -34,13 +34,12 @@
34#include <linux/ramfs.h> 34#include <linux/ramfs.h>
35 35
36#include <asm/uaccess.h> 36#include <asm/uaccess.h>
37#include "internal.h"
37 38
38/* some random number */ 39/* some random number */
39#define RAMFS_MAGIC 0x858458f6 40#define RAMFS_MAGIC 0x858458f6
40 41
41static struct super_operations ramfs_ops; 42static struct super_operations ramfs_ops;
42static struct address_space_operations ramfs_aops;
43static struct inode_operations ramfs_file_inode_operations;
44static struct inode_operations ramfs_dir_inode_operations; 43static struct inode_operations ramfs_dir_inode_operations;
45 44
46static struct backing_dev_info ramfs_backing_dev_info = { 45static struct backing_dev_info ramfs_backing_dev_info = {
@@ -142,25 +141,6 @@ static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char *
142 return error; 141 return error;
143} 142}
144 143
145static struct address_space_operations ramfs_aops = {
146 .readpage = simple_readpage,
147 .prepare_write = simple_prepare_write,
148 .commit_write = simple_commit_write
149};
150
151struct file_operations ramfs_file_operations = {
152 .read = generic_file_read,
153 .write = generic_file_write,
154 .mmap = generic_file_mmap,
155 .fsync = simple_sync_file,
156 .sendfile = generic_file_sendfile,
157 .llseek = generic_file_llseek,
158};
159
160static struct inode_operations ramfs_file_inode_operations = {
161 .getattr = simple_getattr,
162};
163
164static struct inode_operations ramfs_dir_inode_operations = { 144static struct inode_operations ramfs_dir_inode_operations = {
165 .create = ramfs_create, 145 .create = ramfs_create,
166 .lookup = simple_lookup, 146 .lookup = simple_lookup,
diff --git a/fs/ramfs/internal.h b/fs/ramfs/internal.h
new file mode 100644
index 000000000000..272c8a7120b0
--- /dev/null
+++ b/fs/ramfs/internal.h
@@ -0,0 +1,15 @@
1/* internal.h: ramfs internal definitions
2 *
3 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12
13extern struct address_space_operations ramfs_aops;
14extern struct file_operations ramfs_file_operations;
15extern struct inode_operations ramfs_file_inode_operations;
diff --git a/include/linux/ramfs.h b/include/linux/ramfs.h
index e0a4faa9610c..953b6df5d037 100644
--- a/include/linux/ramfs.h
+++ b/include/linux/ramfs.h
@@ -5,6 +5,16 @@ struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev);
5struct super_block *ramfs_get_sb(struct file_system_type *fs_type, 5struct super_block *ramfs_get_sb(struct file_system_type *fs_type,
6 int flags, const char *dev_name, void *data); 6 int flags, const char *dev_name, void *data);
7 7
8#ifndef CONFIG_MMU
9extern unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
10 unsigned long addr,
11 unsigned long len,
12 unsigned long pgoff,
13 unsigned long flags);
14
15extern int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);
16#endif
17
8extern struct file_operations ramfs_file_operations; 18extern struct file_operations ramfs_file_operations;
9extern struct vm_operations_struct generic_file_vm_ops; 19extern struct vm_operations_struct generic_file_vm_ops;
10 20