xfs_iops.c

linux 内核源代码

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_alloc.h"
#include "xfs_dmapi.h"
#include "xfs_quota.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_bmap.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_rtalloc.h"
#include "xfs_error.h"
#include "xfs_itable.h"
#include "xfs_rw.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_buf_item.h"
#include "xfs_utils.h"
#include "xfs_vnodeops.h"

#include <linux/capability.h>
#include <linux/xattr.h>
#include <linux/namei.h>
#include <linux/security.h>

/*
 * Bring the atime in the XFS inode uptodate.
 * Used before logging the inode to disk or when the Linux inode goes away.
 */
void
xfs_synchronize_atime(
	xfs_inode_t	*ip)
{
	bhv_vnode_t	*vp;

	vp = XFS_ITOV_NULL(ip);
	if (vp) {
		ip->i_d.di_atime.t_sec = (__int32_t)vp->i_atime.tv_sec;
		ip->i_d.di_atime.t_nsec = (__int32_t)vp->i_atime.tv_nsec;
	}
}

/*
 * Change the requested timestamp in the given inode.
 * We don't lock across timestamp updates, and we don't log them but
 * we do record the fact that there is dirty information in core.
 *
 * NOTE -- callers MUST combine XFS_ICHGTIME_MOD or XFS_ICHGTIME_CHG
 *		with XFS_ICHGTIME_ACC to be sure that access time
 *		update will take.  Calling first with XFS_ICHGTIME_ACC
 *		and then XFS_ICHGTIME_MOD may fail to modify the access
 *		timestamp if the filesystem is mounted noacctm.
 */
void
xfs_ichgtime(
	xfs_inode_t	*ip,
	int		flags)
{
	struct inode	*inode = vn_to_inode(XFS_ITOV(ip));
	timespec_t	tv;

	nanotime(&tv);
	if (flags & XFS_ICHGTIME_MOD) {
		inode->i_mtime = tv;
		ip->i_d.di_mtime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_mtime.t_nsec = (__int32_t)tv.tv_nsec;
	}
	if (flags & XFS_ICHGTIME_ACC) {
		inode->i_atime = tv;
		ip->i_d.di_atime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_atime.t_nsec = (__int32_t)tv.tv_nsec;
	}
	if (flags & XFS_ICHGTIME_CHG) {
		inode->i_ctime = tv;
		ip->i_d.di_ctime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_ctime.t_nsec = (__int32_t)tv.tv_nsec;
	}

	/*
	 * We update the i_update_core field _after_ changing
	 * the timestamps in order to coordinate properly with
	 * xfs_iflush() so that we don't lose timestamp updates.
	 * This keeps us from having to hold the inode lock
	 * while doing this.  We use the SYNCHRONIZE macro to
	 * ensure that the compiler does not reorder the update
	 * of i_update_core above the timestamp updates above.
	 */
	SYNCHRONIZE();
	ip->i_update_core = 1;
	if (!(inode->i_state & I_NEW))
		mark_inode_dirty_sync(inode);
}

/*
 * Variant on the above which avoids querying the system clock
 * in situations where we know the Linux inode timestamps have
 * just been updated (and so we can update our inode cheaply).
 */
void
xfs_ichgtime_fast(
	xfs_inode_t	*ip,
	struct inode	*inode,
	int		flags)
{
	timespec_t	*tvp;

	/*
	 * Atime updates for read() & friends are handled lazily now, and
	 * explicit updates must go through xfs_ichgtime()
	 */
	ASSERT((flags & XFS_ICHGTIME_ACC) == 0);

	/*
	 * We're not supposed to change timestamps in readonly-mounted
	 * filesystems.  Throw it away if anyone asks us.
	 */
	if (unlikely(IS_RDONLY(inode)))
		return;

	if (flags & XFS_ICHGTIME_MOD) {
		tvp = &inode->i_mtime;
		ip->i_d.di_mtime.t_sec = (__int32_t)tvp->tv_sec;
		ip->i_d.di_mtime.t_nsec = (__int32_t)tvp->tv_nsec;
	}
	if (flags & XFS_ICHGTIME_CHG) {
		tvp = &inode->i_ctime;
		ip->i_d.di_ctime.t_sec = (__int32_t)tvp->tv_sec;
		ip->i_d.di_ctime.t_nsec = (__int32_t)tvp->tv_nsec;
	}

	/*
	 * We update the i_update_core field _after_ changing
	 * the timestamps in order to coordinate properly with
	 * xfs_iflush() so that we don't lose timestamp updates.
	 * This keeps us from having to hold the inode lock
	 * while doing this.  We use the SYNCHRONIZE macro to
	 * ensure that the compiler does not reorder the update
	 * of i_update_core above the timestamp updates above.
	 */
	SYNCHRONIZE();
	ip->i_update_core = 1;
	if (!(inode->i_state & I_NEW))
		mark_inode_dirty_sync(inode);
}


/*
 * Pull the link count and size up from the xfs inode to the linux inode
 */
STATIC void
xfs_validate_fields(
	struct inode		*inode)
{
	struct xfs_inode	*ip = XFS_I(inode);
	loff_t size;

	inode->i_nlink = ip->i_d.di_nlink;
	inode->i_blocks =
		XFS_FSB_TO_BB(ip->i_mount, ip->i_d.di_nblocks +
					   ip->i_delayed_blks);
	/* we're under i_sem so i_size can't change under us */
	size = XFS_ISIZE(ip);
	if (i_size_read(inode) != size)
		i_size_write(inode, size);
}

/*
 * Hook in SELinux.  This is not quite correct yet, what we really need
 * here (as we do for default ACLs) is a mechanism by which creation of
 * these attrs can be journalled at inode creation time (along with the
 * inode, of course, such that log replay can't cause these to be lost).
 */
STATIC int
xfs_init_security(
	bhv_vnode_t	*vp,
	struct inode	*dir)
{
	struct inode	*ip = vn_to_inode(vp);
	size_t		length;
	void		*value;
	char		*name;
	int		error;

	error = security_inode_init_security(ip, dir, &name, &value, &length);
	if (error) {
		if (error == -EOPNOTSUPP)
			return 0;
		return -error;
	}

	error = xfs_attr_set(XFS_I(ip), name, value,
			length, ATTR_SECURE);
	if (!error)
		xfs_iflags_set(XFS_I(ip), XFS_IMODIFIED);

	kfree(name);
	kfree(value);
	return error;
}

/*
 * Determine whether a process has a valid fs_struct (kernel daemons
 * like knfsd don't have an fs_struct).
 *
 * XXX(hch):  nfsd is broken, better fix it instead.
 */
STATIC_INLINE int
xfs_has_fs_struct(struct task_struct *task)
{
	return (task->fs != init_task.fs);
}

STATIC void
xfs_cleanup_inode(
	struct inode	*dir,
	bhv_vnode_t	*vp,
	struct dentry	*dentry,
	int		mode)
{
	struct dentry   teardown = {};

	/* Oh, the horror.
	 * If we can't add the ACL or we fail in
	 * xfs_init_security we must back out.
	 * ENOSPC can hit here, among other things.
	 */
	teardown.d_inode = vn_to_inode(vp);
	teardown.d_name = dentry->d_name;

	if (S_ISDIR(mode))
		xfs_rmdir(XFS_I(dir), &teardown);
	else
		xfs_remove(XFS_I(dir), &teardown);
	VN_RELE(vp);
}

STATIC int
xfs_vn_mknod(
	struct inode	*dir,
	struct dentry	*dentry,
	int		mode,
	dev_t		rdev)
{
	struct inode	*ip;
	bhv_vnode_t	*vp = NULL, *dvp = vn_from_inode(dir);
	xfs_acl_t	*default_acl = NULL;
	attrexists_t	test_default_acl = _ACL_DEFAULT_EXISTS;
	int		error;

	/*
	 * Irix uses Missed'em'V split, but doesn't want to see
	 * the upper 5 bits of (14bit) major.
	 */
	if (unlikely(!sysv_valid_dev(rdev) || MAJOR(rdev) & ~0x1ff))
		return -EINVAL;

	if (unlikely(test_default_acl && test_default_acl(dvp))) {
		if (!_ACL_ALLOC(default_acl)) {
			return -ENOMEM;
		}
		if (!_ACL_GET_DEFAULT(dvp, default_acl)) {
			_ACL_FREE(default_acl);
			default_acl = NULL;
		}
	}

	if (IS_POSIXACL(dir) && !default_acl && xfs_has_fs_struct(current))
		mode &= ~current->fs->umask;

	switch (mode & S_IFMT) {
	case S_IFCHR: case S_IFBLK: case S_IFIFO: case S_IFSOCK:
		rdev = sysv_encode_dev(rdev);
	case S_IFREG:
		error = xfs_create(XFS_I(dir), dentry, mode, rdev, &vp, NULL);
		break;
	case S_IFDIR:
		error = xfs_mkdir(XFS_I(dir), dentry, mode, &vp, NULL);
		break;
	default:
		error = EINVAL;
		break;
	}

	if (unlikely(!error)) {
		error = xfs_init_security(vp, dir);
		if (error)
			xfs_cleanup_inode(dir, vp, dentry, mode);
	}

	if (unlikely(default_acl)) {
		if (!error) {
			error = _ACL_INHERIT(vp, mode, default_acl);
			if (!error)
				xfs_iflags_set(XFS_I(vp), XFS_IMODIFIED);
			else
				xfs_cleanup_inode(dir, vp, dentry, mode);
		}
		_ACL_FREE(default_acl);
	}

	if (likely(!error)) {
		ASSERT(vp);
		ip = vn_to_inode(vp);

		if (S_ISDIR(mode))
			xfs_validate_fields(ip);
		d_instantiate(dentry, ip);
		xfs_validate_fields(dir);
	}
	return -error;
}

STATIC int
xfs_vn_create(
	struct inode	*dir,
	struct dentry	*dentry,
	int		mode,
	struct nameidata *nd)
{
	return xfs_vn_mknod(dir, dentry, mode, 0);
}

STATIC int
xfs_vn_mkdir(
	struct inode	*dir,
	struct dentry	*dentry,
	int		mode)
{
	return xfs_vn_mknod(dir, dentry, mode|S_IFDIR, 0);
}

STATIC struct dentry *
xfs_vn_lookup(
	struct inode	*dir,
	struct dentry	*dentry,
	struct nameidata *nd)
{
	bhv_vnode_t	*cvp;
	int		error;

	if (dentry->d_name.len >= MAXNAMELEN)
		return ERR_PTR(-ENAMETOOLONG);

	error = xfs_lookup(XFS_I(dir), dentry, &cvp);
	if (unlikely(error)) {
		if (unlikely(error != ENOENT))
			return ERR_PTR(-error);
		d_add(dentry, NULL);
		return NULL;
	}

	return d_splice_alias(vn_to_inode(cvp), dentry);
}

STATIC int
xfs_vn_link(
	struct dentry	*old_dentry,
	struct inode	*dir,
	struct dentry	*dentry)
{
	struct inode	*ip;	/* inode of guy being linked to */
	bhv_vnode_t	*vp;	/* vp of name being linked */
	int		error;

	ip = old_dentry->d_inode;	/* inode being linked to */
	vp = vn_from_inode(ip);

	VN_HOLD(vp);