[mirror_ubuntu-artful-kernel.git] / fs / xfs / linux-2.6 / xfs_export.c

/*
 * Copyright (c) 2004-2005 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_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_export.h"
#include "xfs_vnodeops.h"
#include "xfs_bmap_btree.h"
#include "xfs_inode.h"

/*
 * Note that we only accept fileids which are long enough rather than allow
 * the parent generation number to default to zero.  XFS considers zero a
 * valid generation number not an invalid/wildcard value.
 */
static int xfs_fileid_length(int fileid_type)
{
	switch (fileid_type) {
	case FILEID_INO32_GEN:
		return 2;
	case FILEID_INO32_GEN_PARENT:
		return 4;
	case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
		return 3;
	case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
		return 6;
	}
	return 255; /* invalid */
}

STATIC int
xfs_fs_encode_fh(
	struct dentry		*dentry,
	__u32			*fh,
	int			*max_len,
	int			connectable)
{
	struct fid		*fid = (struct fid *)fh;
	struct xfs_fid64	*fid64 = (struct xfs_fid64 *)fh;
	struct inode		*inode = dentry->d_inode;
	int			fileid_type;
	int			len;

	/* Directories don't need their parent encoded, they have ".." */
	if (S_ISDIR(inode->i_mode) || !connectable)
		fileid_type = FILEID_INO32_GEN;
	else
		fileid_type = FILEID_INO32_GEN_PARENT;

	/* filesystem may contain 64bit inode numbers */
	if (!(XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_SMALL_INUMS))
		fileid_type |= XFS_FILEID_TYPE_64FLAG;

	/*
	 * Only encode if there is enough space given.  In practice
	 * this means we can't export a filesystem with 64bit inodes
	 * over NFSv2 with the subtree_check export option; the other
	 * seven combinations work.  The real answer is "don't use v2".
	 */
	len = xfs_fileid_length(fileid_type);
	if (*max_len < len)
		return 255;
	*max_len = len;

	switch (fileid_type) {
	case FILEID_INO32_GEN_PARENT:
		spin_lock(&dentry->d_lock);
		fid->i32.parent_ino = dentry->d_parent->d_inode->i_ino;
		fid->i32.parent_gen = dentry->d_parent->d_inode->i_generation;
		spin_unlock(&dentry->d_lock);
		/*FALLTHRU*/
	case FILEID_INO32_GEN:
		fid->i32.ino = inode->i_ino;
		fid->i32.gen = inode->i_generation;
		break;
	case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
		spin_lock(&dentry->d_lock);
		fid64->parent_ino = dentry->d_parent->d_inode->i_ino;
		fid64->parent_gen = dentry->d_parent->d_inode->i_generation;
		spin_unlock(&dentry->d_lock);
		/*FALLTHRU*/
	case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
		fid64->ino = inode->i_ino;
		fid64->gen = inode->i_generation;
		break;
	}

	return fileid_type;
}

STATIC struct inode *
xfs_nfs_get_inode(
	struct super_block	*sb,
	u64			ino,
	u32			generation)
 {
 	xfs_mount_t		*mp = XFS_M(sb);
	xfs_inode_t		*ip;
	int			error;

	/*
	 * NFS can sometimes send requests for ino 0.  Fail them gracefully.
	 */
	if (ino == 0)
		return ERR_PTR(-ESTALE);

	/*
	 * The XFS_IGET_BULKSTAT means that an invalid inode number is just
	 * fine and not an indication of a corrupted filesystem.  Because
	 * clients can send any kind of invalid file handle, e.g. after
	 * a restore on the server we have to deal with this case gracefully.
	 */
	error = xfs_iget(mp, NULL, ino, XFS_IGET_BULKSTAT,
			 XFS_ILOCK_SHARED, &ip, 0);
	if (error) {
		/*
		 * EINVAL means the inode cluster doesn't exist anymore.
		 * This implies the filehandle is stale, so we should
		 * translate it here.
		 * We don't use ESTALE directly down the chain to not
		 * confuse applications using bulkstat that expect EINVAL.
		 */
		if (error == EINVAL)
			error = ESTALE;
		return ERR_PTR(-error);
	}

	if (ip->i_d.di_gen != generation) {
		xfs_iput_new(ip, XFS_ILOCK_SHARED);
		return ERR_PTR(-ENOENT);
	}

	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	return VFS_I(ip);
}

STATIC struct dentry *
xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid,
		 int fh_len, int fileid_type)
{
	struct xfs_fid64	*fid64 = (struct xfs_fid64 *)fid;
	struct inode		*inode = NULL;

	if (fh_len < xfs_fileid_length(fileid_type))
		return NULL;

	switch (fileid_type) {
	case FILEID_INO32_GEN_PARENT:
	case FILEID_INO32_GEN:
		inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen);
		break;
	case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
	case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
		inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen);
		break;
	}

	return d_obtain_alias(inode);
}

STATIC struct dentry *
xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid,
		 int fh_len, int fileid_type)
{
	struct xfs_fid64	*fid64 = (struct xfs_fid64 *)fid;
	struct inode		*inode = NULL;

	switch (fileid_type) {
	case FILEID_INO32_GEN_PARENT:
		inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino,
					      fid->i32.parent_gen);
		break;
	case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
		inode = xfs_nfs_get_inode(sb, fid64->parent_ino,
					      fid64->parent_gen);
		break;
	}

	return d_obtain_alias(inode);
}

STATIC struct dentry *
xfs_fs_get_parent(
	struct dentry		*child)
{
	int			error;
	struct xfs_inode	*cip;

	error = xfs_lookup(XFS_I(child->d_inode), &xfs_name_dotdot, &cip, NULL);
	if (unlikely(error))
		return ERR_PTR(-error);

	return d_obtain_alias(VFS_I(cip));
}

const struct export_operations xfs_export_operations = {
	.encode_fh		= xfs_fs_encode_fh,
	.fh_to_dentry		= xfs_fs_fh_to_dentry,
	.fh_to_parent		= xfs_fs_fh_to_parent,
	.get_parent		= xfs_fs_get_parent,
};
Commit	Line	Data
1da177e4	1	/*
7b718769 NS	2	* Copyright (c) 2004-2005 Silicon Graphics, Inc.
7b718769 NS	3	* All Rights Reserved.
1da177e4	4	*
7b718769 NS	5	* This program is free software; you can redistribute it and/or
7b718769 NS	6	* modify it under the terms of the GNU General Public License as
1da177e4 LT	7	* published by the Free Software Foundation.
1da177e4 LT	8	*
7b718769 NS	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
1da177e4	13	*
7b718769 NS	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
1da177e4	17	*/
1da177e4 LT	18	#include "xfs.h"
1da177e4 LT	19	#include "xfs_types.h"
da353b0d	20	#include "xfs_inum.h"
1da177e4 LT	21	#include "xfs_log.h"
	22	#include "xfs_trans.h"
	23	#include "xfs_sb.h"
da353b0d	24	#include "xfs_ag.h"
556b8b16	25	#include "xfs_dir2.h"
da353b0d	26	#include "xfs_dmapi.h"
1da177e4 LT	27	#include "xfs_mount.h"
1da177e4 LT	28	#include "xfs_export.h"
739bfb2a CH	29	#include "xfs_vnodeops.h"
	30	#include "xfs_bmap_btree.h"
	31	#include "xfs_inode.h"
1da177e4 LT	32
1da177e4 LT	33	/*
c38344fe CH	34	* Note that we only accept fileids which are long enough rather than allow
	35	* the parent generation number to default to zero. XFS considers zero a
	36	* valid generation number not an invalid/wildcard value.
1da177e4	37	*/
c38344fe	38	static int xfs_fileid_length(int fileid_type)
1da177e4	39	{
c38344fe CH	40	switch (fileid_type) {
	41	case FILEID_INO32_GEN:
	42	return 2;
	43	case FILEID_INO32_GEN_PARENT:
	44	return 4;
	45	case FILEID_INO32_GEN \| XFS_FILEID_TYPE_64FLAG:
	46	return 3;
	47	case FILEID_INO32_GEN_PARENT \| XFS_FILEID_TYPE_64FLAG:
	48	return 6;
1da177e4	49	}
c38344fe	50	return 255; /* invalid */
1da177e4 LT	51	}
1da177e4 LT	52
1da177e4	53	STATIC int
a50cd269	54	xfs_fs_encode_fh(
1da177e4 LT	55	struct dentry *dentry,
	56	__u32 *fh,
	57	int *max_len,
	58	int connectable)
	59	{
c38344fe CH	60	struct fid fid = (struct fid )fh;
c38344fe CH	61	struct xfs_fid64 fid64 = (struct xfs_fid64 )fh;
1da177e4	62	struct inode *inode = dentry->d_inode;
c38344fe	63	int fileid_type;
1da177e4	64	int len;
1da177e4 LT	65
1da177e4 LT	66	/* Directories don't need their parent encoded, they have ".." */
24bd861d	67	if (S_ISDIR(inode->i_mode) \|\| !connectable)
c38344fe CH	68	fileid_type = FILEID_INO32_GEN;
	69	else
	70	fileid_type = FILEID_INO32_GEN_PARENT;
	71
	72	/* filesystem may contain 64bit inode numbers */
	73	if (!(XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_SMALL_INUMS))
	74	fileid_type \|= XFS_FILEID_TYPE_64FLAG;
1da177e4 LT	75
	76	/*
	77	* Only encode if there is enough space given. In practice
	78	* this means we can't export a filesystem with 64bit inodes
	79	* over NFSv2 with the subtree_check export option; the other
	80	* seven combinations work. The real answer is "don't use v2".
	81	*/
c38344fe	82	len = xfs_fileid_length(fileid_type);
1da177e4 LT	83	if (*max_len < len)
	84	return 255;
	85	*max_len = len;
	86
c38344fe CH	87	switch (fileid_type) {
c38344fe CH	88	case FILEID_INO32_GEN_PARENT:
1da177e4	89	spin_lock(&dentry->d_lock);
c38344fe CH	90	fid->i32.parent_ino = dentry->d_parent->d_inode->i_ino;
c38344fe CH	91	fid->i32.parent_gen = dentry->d_parent->d_inode->i_generation;
1da177e4	92	spin_unlock(&dentry->d_lock);
c38344fe CH	93	/FALLTHRU/
	94	case FILEID_INO32_GEN:
	95	fid->i32.ino = inode->i_ino;
	96	fid->i32.gen = inode->i_generation;
	97	break;
	98	case FILEID_INO32_GEN_PARENT \| XFS_FILEID_TYPE_64FLAG:
	99	spin_lock(&dentry->d_lock);
	100	fid64->parent_ino = dentry->d_parent->d_inode->i_ino;
	101	fid64->parent_gen = dentry->d_parent->d_inode->i_generation;
	102	spin_unlock(&dentry->d_lock);
	103	/FALLTHRU/
	104	case FILEID_INO32_GEN \| XFS_FILEID_TYPE_64FLAG:
	105	fid64->ino = inode->i_ino;
	106	fid64->gen = inode->i_generation;
	107	break;
1da177e4	108	}
c38344fe CH	109
c38344fe CH	110	return fileid_type;
1da177e4 LT	111	}
1da177e4 LT	112
c38344fe CH	113	STATIC struct inode *
c38344fe CH	114	xfs_nfs_get_inode(
1da177e4	115	struct super_block *sb,
c38344fe CH	116	u64 ino,
	117	u32 generation)
	118	{
f71354bc CH	119	xfs_mount_t *mp = XFS_M(sb);
f71354bc CH	120	xfs_inode_t *ip;
1da177e4 LT	121	int error;
1da177e4 LT	122
f71354bc CH	123	/*
	124	* NFS can sometimes send requests for ino 0. Fail them gracefully.
	125	*/
	126	if (ino == 0)
	127	return ERR_PTR(-ESTALE);
1da177e4	128
c9a98553 CH	129	/*
	130	* The XFS_IGET_BULKSTAT means that an invalid inode number is just
	131	* fine and not an indication of a corrupted filesystem. Because
	132	* clients can send any kind of invalid file handle, e.g. after
	133	* a restore on the server we have to deal with this case gracefully.
	134	*/
	135	error = xfs_iget(mp, NULL, ino, XFS_IGET_BULKSTAT,
	136	XFS_ILOCK_SHARED, &ip, 0);
	137	if (error) {
	138	/*
	139	* EINVAL means the inode cluster doesn't exist anymore.
	140	* This implies the filehandle is stale, so we should
	141	* translate it here.
	142	* We don't use ESTALE directly down the chain to not
	143	* confuse applications using bulkstat that expect EINVAL.
	144	*/
	145	if (error == EINVAL)
	146	error = ESTALE;
c38344fe	147	return ERR_PTR(-error);
c9a98553	148	}
f71354bc	149
6a7f422d	150	if (ip->i_d.di_gen != generation) {
f71354bc CH	151	xfs_iput_new(ip, XFS_ILOCK_SHARED);
	152	return ERR_PTR(-ENOENT);
	153	}
c38344fe	154
f71354bc	155	xfs_iunlock(ip, XFS_ILOCK_SHARED);
01651646	156	return VFS_I(ip);
c38344fe CH	157	}
	158
	159	STATIC struct dentry *
	160	xfs_fs_fh_to_dentry(struct super_block sb, struct fid fid,
	161	int fh_len, int fileid_type)
	162	{
	163	struct xfs_fid64 fid64 = (struct xfs_fid64 )fid;
	164	struct inode *inode = NULL;
c38344fe CH	165
	166	if (fh_len < xfs_fileid_length(fileid_type))
	167	return NULL;
	168
	169	switch (fileid_type) {
	170	case FILEID_INO32_GEN_PARENT:
	171	case FILEID_INO32_GEN:
	172	inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen);
	173	break;
	174	case FILEID_INO32_GEN_PARENT \| XFS_FILEID_TYPE_64FLAG:
	175	case FILEID_INO32_GEN \| XFS_FILEID_TYPE_64FLAG:
	176	inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen);
	177	break;
	178	}
	179
44003728	180	return d_obtain_alias(inode);
c38344fe CH	181	}
	182
	183	STATIC struct dentry *
	184	xfs_fs_fh_to_parent(struct super_block sb, struct fid fid,
	185	int fh_len, int fileid_type)
	186	{
	187	struct xfs_fid64 fid64 = (struct xfs_fid64 )fid;
	188	struct inode *inode = NULL;
c38344fe CH	189
	190	switch (fileid_type) {
	191	case FILEID_INO32_GEN_PARENT:
	192	inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino,
	193	fid->i32.parent_gen);
	194	break;
	195	case FILEID_INO32_GEN_PARENT \| XFS_FILEID_TYPE_64FLAG:
	196	inode = xfs_nfs_get_inode(sb, fid64->parent_ino,
	197	fid64->parent_gen);
	198	break;
	199	}
	200
44003728	201	return d_obtain_alias(inode);
1da177e4 LT	202	}
	203
	204	STATIC struct dentry *
a50cd269	205	xfs_fs_get_parent(
1da177e4 LT	206	struct dentry *child)
	207	{
	208	int error;
ef1f5e7a	209	struct xfs_inode *cip;
1da177e4	210
384f3ced	211	error = xfs_lookup(XFS_I(child->d_inode), &xfs_name_dotdot, &cip, NULL);
1da177e4 LT	212	if (unlikely(error))
	213	return ERR_PTR(-error);
	214
44003728	215	return d_obtain_alias(VFS_I(cip));
1da177e4 LT	216	}
1da177e4 LT	217
39655164	218	const struct export_operations xfs_export_operations = {
a50cd269	219	.encode_fh = xfs_fs_encode_fh,
c38344fe CH	220	.fh_to_dentry = xfs_fs_fh_to_dentry,
c38344fe CH	221	.fh_to_parent = xfs_fs_fh_to_parent,
a50cd269	222	.get_parent = xfs_fs_get_parent,
1da177e4	223	};