patch-2.4.22 linux-2.4.22/arch/ia64/sn/io/hwgfs/ramfs.c
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- Lines: 342
- Date:
2003-08-25 04:44:39.000000000 -0700
- Orig file:
linux-2.4.21/arch/ia64/sn/io/hwgfs/ramfs.c
- Orig date:
1969-12-31 16:00:00.000000000 -0800
diff -urN linux-2.4.21/arch/ia64/sn/io/hwgfs/ramfs.c linux-2.4.22/arch/ia64/sn/io/hwgfs/ramfs.c
@@ -0,0 +1,341 @@
+/* $Id$
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1992 - 1997, 2000-2003 Silicon Graphics, Inc. All rights reserved.
+ */
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/machvec.h>
+
+/* some random number */
+#define HWGFS_MAGIC 0x12061983
+
+static struct super_operations hwgfs_ops;
+static struct address_space_operations hwgfs_aops;
+static struct file_operations hwgfs_file_operations;
+static struct inode_operations hwgfs_dir_inode_operations;
+
+static int hwgfs_statfs(struct super_block *sb, struct statfs *buf)
+{
+ buf->f_type = HWGFS_MAGIC;
+ buf->f_bsize = PAGE_CACHE_SIZE;
+ buf->f_namelen = 255;
+ return 0;
+}
+
+/*
+ * Lookup the data. This is trivial - if the dentry didn't already
+ * exist, we know it is negative.
+ */
+static struct dentry * hwgfs_lookup(struct inode *dir, struct dentry *dentry)
+{
+ d_add(dentry, NULL);
+ return NULL;
+}
+
+/*
+ * Read a page. Again trivial. If it didn't already exist
+ * in the page cache, it is zero-filled.
+ */
+static int hwgfs_readpage(struct file *file, struct page * page)
+{
+ if (!Page_Uptodate(page)) {
+ memset(kmap(page), 0, PAGE_CACHE_SIZE);
+ kunmap(page);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ }
+ UnlockPage(page);
+ return 0;
+}
+
+static int hwgfs_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
+{
+ void *addr = kmap(page);
+ if (!Page_Uptodate(page)) {
+ memset(addr, 0, PAGE_CACHE_SIZE);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ }
+ SetPageDirty(page);
+ return 0;
+}
+
+static int hwgfs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
+{
+ struct inode *inode = page->mapping->host;
+ loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+
+ kunmap(page);
+ if (pos > inode->i_size)
+ inode->i_size = pos;
+ return 0;
+}
+
+struct inode *hwgfs_get_inode(struct super_block *sb, int mode, int dev)
+{
+ struct inode * inode = new_inode(sb);
+
+ if (inode) {
+ inode->i_mode = mode;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ inode->i_rdev = NODEV;
+ inode->i_mapping->a_ops = &hwgfs_aops;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ switch (mode & S_IFMT) {
+ default:
+ init_special_inode(inode, mode, dev);
+ break;
+ case S_IFREG:
+ inode->i_fop = &hwgfs_file_operations;
+ break;
+ case S_IFDIR:
+ inode->i_op = &hwgfs_dir_inode_operations;
+ inode->i_fop = &dcache_dir_ops;
+ break;
+ case S_IFLNK:
+ inode->i_op = &page_symlink_inode_operations;
+ break;
+ }
+ }
+ return inode;
+}
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+static int hwgfs_mknod(struct inode *dir, struct dentry *dentry, int mode, int dev)
+{
+ struct inode * inode = hwgfs_get_inode(dir->i_sb, mode, dev);
+ int error = -ENOSPC;
+
+ if (inode) {
+ d_instantiate(dentry, inode);
+ dget(dentry); /* Extra count - pin the dentry in core */
+ error = 0;
+ }
+ return error;
+}
+
+static int hwgfs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
+{
+ return hwgfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+}
+
+static int hwgfs_create(struct inode *dir, struct dentry *dentry, int mode)
+{
+ return hwgfs_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+/*
+ * Link a file..
+ */
+static int hwgfs_link(struct dentry *old_dentry, struct inode * dir, struct dentry * dentry)
+{
+ struct inode *inode = old_dentry->d_inode;
+
+ if (S_ISDIR(inode->i_mode))
+ return -EPERM;
+
+ inode->i_nlink++;
+ atomic_inc(&inode->i_count); /* New dentry reference */
+ dget(dentry); /* Extra pinning count for the created dentry */
+ d_instantiate(dentry, inode);
+ return 0;
+}
+
+static inline int hwgfs_positive(struct dentry *dentry)
+{
+ return dentry->d_inode && !d_unhashed(dentry);
+}
+
+/*
+ * Check that a directory is empty (this works
+ * for regular files too, they'll just always be
+ * considered empty..).
+ *
+ * Note that an empty directory can still have
+ * children, they just all have to be negative..
+ */
+static int hwgfs_empty(struct dentry *dentry)
+{
+ struct list_head *list;
+
+ spin_lock(&dcache_lock);
+ list = dentry->d_subdirs.next;
+
+ while (list != &dentry->d_subdirs) {
+ struct dentry *de = list_entry(list, struct dentry, d_child);
+
+ if (hwgfs_positive(de)) {
+ spin_unlock(&dcache_lock);
+ return 0;
+ }
+ list = list->next;
+ }
+ spin_unlock(&dcache_lock);
+ return 1;
+}
+
+/*
+ * This works for both directories and regular files.
+ * (non-directories will always have empty subdirs)
+ */
+static int hwgfs_unlink(struct inode * dir, struct dentry *dentry)
+{
+ int retval = -ENOTEMPTY;
+
+ if (hwgfs_empty(dentry)) {
+ struct inode *inode = dentry->d_inode;
+
+ inode->i_nlink--;
+ dput(dentry); /* Undo the count from "create" - this does all the work */
+ retval = 0;
+ }
+ return retval;
+}
+
+#define hwgfs_rmdir hwgfs_unlink
+
+/*
+ * The VFS layer already does all the dentry stuff for rename,
+ * we just have to decrement the usage count for the target if
+ * it exists so that the VFS layer correctly free's it when it
+ * gets overwritten.
+ */
+static int hwgfs_rename(struct inode * old_dir, struct dentry *old_dentry, struct inode * new_dir,struct dentry *new_dentry)
+{
+ int error = -ENOTEMPTY;
+
+ if (hwgfs_empty(new_dentry)) {
+ struct inode *inode = new_dentry->d_inode;
+ if (inode) {
+ inode->i_nlink--;
+ dput(new_dentry);
+ }
+ error = 0;
+ }
+ return error;
+}
+
+static int hwgfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
+{
+ int error;
+
+ error = hwgfs_mknod(dir, dentry, S_IFLNK | S_IRWXUGO, 0);
+ if (!error) {
+ int l = strlen(symname)+1;
+ struct inode *inode = dentry->d_inode;
+ error = block_symlink(inode, symname, l);
+ }
+ return error;
+}
+
+static int hwgfs_sync_file(struct file * file, struct dentry *dentry, int datasync)
+{
+ return 0;
+}
+
+static struct address_space_operations hwgfs_aops = {
+ .readpage = hwgfs_readpage,
+ .writepage = fail_writepage,
+ .prepare_write = hwgfs_prepare_write,
+ .commit_write = hwgfs_commit_write
+};
+
+static struct file_operations hwgfs_file_operations = {
+ .read = generic_file_read,
+ .write = generic_file_write,
+ .mmap = generic_file_mmap,
+ .fsync = hwgfs_sync_file,
+};
+
+static struct inode_operations hwgfs_dir_inode_operations = {
+ .create = hwgfs_create,
+ .lookup = hwgfs_lookup,
+ .link = hwgfs_link,
+ .unlink = hwgfs_unlink,
+ .symlink = hwgfs_symlink,
+ .mkdir = hwgfs_mkdir,
+ .rmdir = hwgfs_rmdir,
+ .mknod = hwgfs_mknod,
+ .rename = hwgfs_rename,
+};
+
+static struct super_operations hwgfs_ops = {
+ .statfs = hwgfs_statfs,
+ .put_inode = force_delete,
+};
+
+static struct super_block *hwgfs_read_super(struct super_block * sb, void * data, int silent)
+{
+ struct inode * inode;
+ struct dentry * root;
+
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = HWGFS_MAGIC;
+ sb->s_op = &hwgfs_ops;
+ inode = hwgfs_get_inode(sb, S_IFDIR | 0755, 0);
+ if (!inode)
+ return NULL;
+
+ root = d_alloc_root(inode);
+ if (!root) {
+ iput(inode);
+ return NULL;
+ }
+ sb->s_root = root;
+ return sb;
+}
+
+static struct file_system_type hwgfs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "hwgfs",
+ .read_super = hwgfs_read_super,
+ .fs_flags = FS_SINGLE|FS_LITTER,
+};
+
+struct vfsmount *hwgfs_vfsmount;
+
+int __init init_hwgfs_fs(void)
+{
+ int error;
+
+ if (!ia64_platform_is("sn2"))
+ return -ENODEV;
+
+ error = register_filesystem(&hwgfs_fs_type);
+ if (error)
+ return error;
+
+ hwgfs_vfsmount = kern_mount(&hwgfs_fs_type);
+ if (IS_ERR(hwgfs_vfsmount))
+ goto fail;
+ return 0;
+
+fail:
+ unregister_filesystem(&hwgfs_fs_type);
+ return PTR_ERR(hwgfs_vfsmount);
+}
+
+static void __exit exit_hwgfs_fs(void)
+{
+ unregister_filesystem(&hwgfs_fs_type);
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(init_hwgfs_fs)
+module_exit(exit_hwgfs_fs)
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