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xen/privcmd: create address space to allow writable mmaps

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These are necessary to allow writeable mmap of the privcmd node to
succeed without being marked read-only for writenotify purposes. Which
in turn is necessary to allow mappings of foreign guest pages

[ Impact: bugfix: allow writable mappings ]

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
This commit is contained in:
Jeremy Fitzhardinge
2009-02-09 12:05:49 -08:00
committed by Jeremy Fitzhardinge
parent 1c5de1939c
commit 24a89b5be4
1 changed files with 38 additions and 4 deletions
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42
drivers/xen/xenfs/super.c
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@@ -12,6 +12,8 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/fs.h> #include <linux/fs.h>
#include <linux/magic.h> #include <linux/magic.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include <xen/xen.h> #include <xen/xen.h>
@@ -22,12 +24,30 @@
MODULE_DESCRIPTION("Xen filesystem"); MODULE_DESCRIPTION("Xen filesystem");
MODULE_LICENSE("GPL"); MODULE_LICENSE("GPL");
static int xenfs_set_page_dirty(struct page *page)
{
if (!PageDirty(page))
SetPageDirty(page);
return 0;
}
static const struct address_space_operations xenfs_aops = {
.set_page_dirty = xenfs_set_page_dirty,
};
static struct backing_dev_info xenfs_backing_dev_info = {
.ra_pages = 0, /* No readahead */
.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
};
static struct inode *xenfs_make_inode(struct super_block *sb, int mode) static struct inode *xenfs_make_inode(struct super_block *sb, int mode)
{ {
struct inode *ret = new_inode(sb); struct inode *ret = new_inode(sb);
if (ret) { if (ret) {
ret->i_mode = mode; ret->i_mode = mode;
ret->i_mapping->a_ops = &xenfs_aops;
ret->i_mapping->backing_dev_info = &xenfs_backing_dev_info;
ret->i_uid = ret->i_gid = 0; ret->i_uid = ret->i_gid = 0;
ret->i_blocks = 0; ret->i_blocks = 0;
ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
@@ -119,11 +139,25 @@ static struct file_system_type xenfs_type = {
static int __init xenfs_init(void) static int __init xenfs_init(void)
{ {
if (xen_domain()) int err;
return register_filesystem(&xenfs_type); if (!xen_domain()) {
printk(KERN_INFO "xenfs: not registering filesystem on non-xen platform\n");
printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n");
return 0; return 0;
}
err = register_filesystem(&xenfs_type);
if (err) {
printk(KERN_ERR "xenfs: Unable to register filesystem!\n");
goto out;
}
err = bdi_init(&xenfs_backing_dev_info);
if (err)
unregister_filesystem(&xenfs_type);
out:
return err;
} }
static void __exit xenfs_exit(void) static void __exit xenfs_exit(void)