inode.c

linux 内核源代码

/*
 *  linux/fs/hfsplus/inode.c
 *
 * Copyright (C) 2001
 * Brad Boyer ([e-mail])
 * (C) 2003 Ardis Technologies <[e-mail]>
 *
 * Inode handling routines
 */

#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/mpage.h>
#include <linux/sched.h>

#include "hfsplus_fs.h"
#include "hfsplus_raw.h"

static int hfsplus_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page, hfsplus_get_block);
}

static int hfsplus_writepage(struct page *page, struct writeback_control *wbc)
{
	return block_write_full_page(page, hfsplus_get_block, wbc);
}

static int hfsplus_write_begin(struct file *file, struct address_space *mapping,
			loff_t pos, unsigned len, unsigned flags,
			struct page **pagep, void **fsdata)
{
	*pagep = NULL;
	return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
				hfsplus_get_block,
				&HFSPLUS_I(mapping->host).phys_size);
}

static sector_t hfsplus_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping, block, hfsplus_get_block);
}

static int hfsplus_releasepage(struct page *page, gfp_t mask)
{
	struct inode *inode = page->mapping->host;
	struct super_block *sb = inode->i_sb;
	struct hfs_btree *tree;
	struct hfs_bnode *node;
	u32 nidx;
	int i, res = 1;

	switch (inode->i_ino) {
	case HFSPLUS_EXT_CNID:
		tree = HFSPLUS_SB(sb).ext_tree;
		break;
	case HFSPLUS_CAT_CNID:
		tree = HFSPLUS_SB(sb).cat_tree;
		break;
	case HFSPLUS_ATTR_CNID:
		tree = HFSPLUS_SB(sb).attr_tree;
		break;
	default:
		BUG();
		return 0;
	}
	if (tree->node_size >= PAGE_CACHE_SIZE) {
		nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
		spin_lock(&tree->hash_lock);
		node = hfs_bnode_findhash(tree, nidx);
		if (!node)
			;
		else if (atomic_read(&node->refcnt))
			res = 0;
		if (res && node) {
			hfs_bnode_unhash(node);
			hfs_bnode_free(node);
		}
		spin_unlock(&tree->hash_lock);
	} else {
		nidx = page->index << (PAGE_CACHE_SHIFT - tree->node_size_shift);
		i = 1 << (PAGE_CACHE_SHIFT - tree->node_size_shift);
		spin_lock(&tree->hash_lock);
		do {
			node = hfs_bnode_findhash(tree, nidx++);
			if (!node)
				continue;
			if (atomic_read(&node->refcnt)) {
				res = 0;
				break;
			}
			hfs_bnode_unhash(node);
			hfs_bnode_free(node);
		} while (--i && nidx < tree->node_count);
		spin_unlock(&tree->hash_lock);
	}
	return res ? try_to_free_buffers(page) : 0;
}

static ssize_t hfsplus_direct_IO(int rw, struct kiocb *iocb,
		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_path.dentry->d_inode->i_mapping->host;

	return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
				  offset, nr_segs, hfsplus_get_block, NULL);
}

static int hfsplus_writepages(struct address_space *mapping,
			      struct writeback_control *wbc)
{
	return mpage_writepages(mapping, wbc, hfsplus_get_block);
}

const struct address_space_operations hfsplus_btree_aops = {
	.readpage	= hfsplus_readpage,
	.writepage	= hfsplus_writepage,
	.sync_page	= block_sync_page,
	.write_begin	= hfsplus_write_begin,
	.write_end	= generic_write_end,
	.bmap		= hfsplus_bmap,
	.releasepage	= hfsplus_releasepage,
};

const struct address_space_operations hfsplus_aops = {
	.readpage	= hfsplus_readpage,
	.writepage	= hfsplus_writepage,
	.sync_page	= block_sync_page,
	.write_begin	= hfsplus_write_begin,
	.write_end	= generic_write_end,
	.bmap		= hfsplus_bmap,
	.direct_IO	= hfsplus_direct_IO,
	.writepages	= hfsplus_writepages,
};

struct dentry_operations hfsplus_dentry_operations = {
	.d_hash       = hfsplus_hash_dentry,
	.d_compare    = hfsplus_compare_dentry,
};

static struct dentry *hfsplus_file_lookup(struct inode *dir, struct dentry *dentry,
					  struct nameidata *nd)
{
	struct hfs_find_data fd;
	struct super_block *sb = dir->i_sb;
	struct inode *inode = NULL;
	int err;

	if (HFSPLUS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
		goto out;

	inode = HFSPLUS_I(dir).rsrc_inode;
	if (inode)
		goto out;

	inode = new_inode(sb);
	if (!inode)
		return ERR_PTR(-ENOMEM);

	inode->i_ino = dir->i_ino;
	INIT_LIST_HEAD(&HFSPLUS_I(inode).open_dir_list);
	init_MUTEX(&HFSPLUS_I(inode).extents_lock);
	HFSPLUS_I(inode).flags = HFSPLUS_FLG_RSRC;

	hfs_find_init(HFSPLUS_SB(sb).cat_tree, &fd);
	err = hfsplus_find_cat(sb, dir->i_ino, &fd);
	if (!err)
		err = hfsplus_cat_read_inode(inode, &fd);
	hfs_find_exit(&fd);
	if (err) {
		iput(inode);
		return ERR_PTR(err);
	}
	HFSPLUS_I(inode).rsrc_inode = dir;
	HFSPLUS_I(dir).rsrc_inode = inode;
	igrab(dir);
	hlist_add_head(&inode->i_hash, &HFSPLUS_SB(sb).rsrc_inodes);
	mark_inode_dirty(inode);
out:
	d_add(dentry, inode);
	return NULL;
}

static void hfsplus_get_perms(struct inode *inode, struct hfsplus_perm *perms, int dir)
{
	struct super_block *sb = inode->i_sb;
	u16 mode;

	mode = be16_to_cpu(perms->mode);

	inode->i_uid = be32_to_cpu(perms->owner);
	if (!inode->i_uid && !mode)
		inode->i_uid = HFSPLUS_SB(sb).uid;

	inode->i_gid = be32_to_cpu(perms->group);
	if (!inode->i_gid && !mode)
		inode->i_gid = HFSPLUS_SB(sb).gid;

	if (dir) {
		mode = mode ? (mode & S_IALLUGO) :
			(S_IRWXUGO & ~(HFSPLUS_SB(sb).umask));
		mode |= S_IFDIR;
	} else if (!mode)
		mode = S_IFREG | ((S_IRUGO|S_IWUGO) &
			~(HFSPLUS_SB(sb).umask));
	inode->i_mode = mode;

	HFSPLUS_I(inode).rootflags = perms->rootflags;
	HFSPLUS_I(inode).userflags = perms->userflags;
	if (perms->rootflags & HFSPLUS_FLG_IMMUTABLE)
		inode->i_flags |= S_IMMUTABLE;
	else
		inode->i_flags &= ~S_IMMUTABLE;
	if (perms->rootflags & HFSPLUS_FLG_APPEND)
		inode->i_flags |= S_APPEND;
	else
		inode->i_flags &= ~S_APPEND;
}

static void hfsplus_set_perms(struct inode *inode, struct hfsplus_perm *perms)
{
	if (inode->i_flags & S_IMMUTABLE)
		perms->rootflags |= HFSPLUS_FLG_IMMUTABLE;
	else
		perms->rootflags &= ~HFSPLUS_FLG_IMMUTABLE;
	if (inode->i_flags & S_APPEND)
		perms->rootflags |= HFSPLUS_FLG_APPEND;
	else
		perms->rootflags &= ~HFSPLUS_FLG_APPEND;
	perms->userflags = HFSPLUS_I(inode).userflags;
	perms->mode = cpu_to_be16(inode->i_mode);
	perms->owner = cpu_to_be32(inode->i_uid);
	perms->group = cpu_to_be32(inode->i_gid);
	perms->dev = cpu_to_be32(HFSPLUS_I(inode).dev);
}

static int hfsplus_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	/* MAY_EXEC is also used for lookup, if no x bit is set allow lookup,
	 * open_exec has the same test, so it's still not executable, if a x bit
	 * is set fall back to standard permission check.
	 */
	if (S_ISREG(inode->i_mode) && mask & MAY_EXEC && !(inode->i_mode & 0111))
		return 0;
	return generic_permission(inode, mask, NULL);
}


static int hfsplus_file_open(struct inode *inode, struct file *file)
{
	if (HFSPLUS_IS_RSRC(inode))
		inode = HFSPLUS_I(inode).rsrc_inode;
	if (atomic_read(&file->f_count) != 1)
		return 0;
	atomic_inc(&HFSPLUS_I(inode).opencnt);
	return 0;
}

static int hfsplus_file_release(struct inode *inode, struct file *file)
{
	struct super_block *sb = inode->i_sb;

	if (HFSPLUS_IS_RSRC(inode))
		inode = HFSPLUS_I(inode).rsrc_inode;
	if (atomic_read(&file->f_count) != 0)
		return 0;
	if (atomic_dec_and_test(&HFSPLUS_I(inode).opencnt)) {
		mutex_lock(&inode->i_mutex);
		hfsplus_file_truncate(inode);
		if (inode->i_flags & S_DEAD) {