xen/privcmd: create address space to allow writable mmaps
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>
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1c5de1939c
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24a89b5be4
1 changed files with 38 additions and 4 deletions
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@ -12,6 +12,8 @@
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/magic.h>
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#include <linux/mm.h>
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#include <linux/backing-dev.h>
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#include <xen/xen.h>
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@ -22,12 +24,30 @@
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MODULE_DESCRIPTION("Xen filesystem");
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MODULE_LICENSE("GPL");
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static int xenfs_set_page_dirty(struct page *page)
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{
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if (!PageDirty(page))
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SetPageDirty(page);
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return 0;
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}
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static const struct address_space_operations xenfs_aops = {
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.set_page_dirty = xenfs_set_page_dirty,
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};
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static struct backing_dev_info xenfs_backing_dev_info = {
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
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};
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static struct inode *xenfs_make_inode(struct super_block *sb, int mode)
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{
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struct inode *ret = new_inode(sb);
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if (ret) {
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ret->i_mode = mode;
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ret->i_mapping->a_ops = &xenfs_aops;
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ret->i_mapping->backing_dev_info = &xenfs_backing_dev_info;
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ret->i_uid = ret->i_gid = 0;
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ret->i_blocks = 0;
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ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
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@ -119,11 +139,25 @@ static struct file_system_type xenfs_type = {
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static int __init xenfs_init(void)
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{
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if (xen_domain())
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return register_filesystem(&xenfs_type);
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int err;
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if (!xen_domain()) {
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printk(KERN_INFO "xenfs: not registering filesystem on non-xen platform\n");
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return 0;
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}
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printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n");
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return 0;
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err = register_filesystem(&xenfs_type);
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if (err) {
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printk(KERN_ERR "xenfs: Unable to register filesystem!\n");
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goto out;
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}
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err = bdi_init(&xenfs_backing_dev_info);
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if (err)
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unregister_filesystem(&xenfs_type);
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out:
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return err;
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}
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static void __exit xenfs_exit(void)
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