[mirror_ubuntu-zesty-kernel.git] / fs / xfs / 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_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_mount.h"
#include "xfs_export.h"
#include "xfs_vnodeops.h"
#include "xfs_bmap_btree.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_trace.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 inode	*inode,
	__u32		*fh,
	int		*max_len,
	struct inode	*parent)
{
	struct fid		*fid = (struct fid *)fh;
	struct xfs_fid64	*fid64 = (struct xfs_fid64 *)fh;
	int			fileid_type;
	int			len;

	/* Directories don't need their parent encoded, they have ".." */
	if (!parent)
		fileid_type = FILEID_INO32_GEN;
	else
		fileid_type = FILEID_INO32_GEN_PARENT;

	/*
	 * If the the filesystem may contain 64bit inode numbers, we need
	 * to use larger file handles that can represent them.
	 *
	 * While we only allocate inodes that do not fit into 32 bits any
	 * large enough filesystem may contain them, thus the slightly
	 * confusing looking conditional below.
	 */
	if (!(XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_SMALL_INUMS) ||
	    (XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_32BITINODES))
		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) {
		*max_len = len;
		return 255;
	}
	*max_len = len;

	switch (fileid_type) {
	case FILEID_INO32_GEN_PARENT:
		fid->i32.parent_ino = XFS_I(parent)->i_ino;
		fid->i32.parent_gen = parent->i_generation;
		/*FALLTHRU*/
	case FILEID_INO32_GEN:
		fid->i32.ino = XFS_I(inode)->i_ino;
		fid->i32.gen = inode->i_generation;
		break;
	case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
		fid64->parent_ino = XFS_I(parent)->i_ino;
		fid64->parent_gen = parent->i_generation;
		/*FALLTHRU*/
	case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
		fid64->ino = XFS_I(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_UNTRUSTED means that an invalid inode number is just
	 * fine and not an indication of a corrupted filesystem as clients can
	 * send invalid file handles and we have to handle it gracefully..
	 */
	error = xfs_iget(mp, NULL, ino, XFS_IGET_UNTRUSTED, 0, &ip);
	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 == ENOENT)
			error = ESTALE;
		return ERR_PTR(-error);
	}

	if (ip->i_d.di_gen != generation) {
		IRELE(ip);
		return ERR_PTR(-ESTALE);
	}

	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;

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

STATIC int
xfs_fs_nfs_commit_metadata(
	struct inode		*inode)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	xfs_lsn_t		lsn = 0;

	xfs_ilock(ip, XFS_ILOCK_SHARED);
	if (xfs_ipincount(ip))
		lsn = ip->i_itemp->ili_last_lsn;
	xfs_iunlock(ip, XFS_ILOCK_SHARED);

	if (!lsn)
		return 0;
	return _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
}

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_metadata	= xfs_fs_nfs_commit_metadata,
};
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"
1da177e4 LT	20	#include "xfs_log.h"
	21	#include "xfs_trans.h"
	22	#include "xfs_sb.h"
da353b0d	23	#include "xfs_ag.h"
556b8b16	24	#include "xfs_dir2.h"
1da177e4 LT	25	#include "xfs_mount.h"
1da177e4 LT	26	#include "xfs_export.h"
739bfb2a CH	27	#include "xfs_vnodeops.h"
	28	#include "xfs_bmap_btree.h"
	29	#include "xfs_inode.h"
978ebd97	30	#include "xfs_inode_item.h"
ef35e925	31	#include "xfs_trace.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(
b0b0382b AV	55	struct inode *inode,
	56	__u32 *fh,
	57	int *max_len,
	58	struct inode *parent)
1da177e4	59	{
c38344fe CH	60	struct fid fid = (struct fid )fh;
c38344fe CH	61	struct xfs_fid64 fid64 = (struct xfs_fid64 )fh;
c38344fe	62	int fileid_type;
1da177e4	63	int len;
1da177e4 LT	64
1da177e4 LT	65	/* Directories don't need their parent encoded, they have ".." */
b0b0382b	66	if (!parent)
c38344fe CH	67	fileid_type = FILEID_INO32_GEN;
	68	else
	69	fileid_type = FILEID_INO32_GEN_PARENT;
	70
576ecb8e SK	71	/*
	72	* If the the filesystem may contain 64bit inode numbers, we need
	73	* to use larger file handles that can represent them.
	74	*
	75	* While we only allocate inodes that do not fit into 32 bits any
	76	* large enough filesystem may contain them, thus the slightly
	77	* confusing looking conditional below.
	78	*/
	79	if (!(XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_SMALL_INUMS) \|\|
	80	(XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_32BITINODES))
c38344fe	81	fileid_type \|= XFS_FILEID_TYPE_64FLAG;
1da177e4 LT	82
	83	/*
	84	* Only encode if there is enough space given. In practice
	85	* this means we can't export a filesystem with 64bit inodes
	86	* over NFSv2 with the subtree_check export option; the other
	87	* seven combinations work. The real answer is "don't use v2".
	88	*/
c38344fe	89	len = xfs_fileid_length(fileid_type);
5fe0c237 AK	90	if (*max_len < len) {
5fe0c237 AK	91	*max_len = len;
1da177e4	92	return 255;
5fe0c237	93	}
1da177e4 LT	94	*max_len = len;
1da177e4 LT	95
c38344fe CH	96	switch (fileid_type) {
c38344fe CH	97	case FILEID_INO32_GEN_PARENT:
b0b0382b AV	98	fid->i32.parent_ino = XFS_I(parent)->i_ino;
b0b0382b AV	99	fid->i32.parent_gen = parent->i_generation;
c38344fe CH	100	/FALLTHRU/
c38344fe CH	101	case FILEID_INO32_GEN:
c29f7d45	102	fid->i32.ino = XFS_I(inode)->i_ino;
c38344fe CH	103	fid->i32.gen = inode->i_generation;
	104	break;
	105	case FILEID_INO32_GEN_PARENT \| XFS_FILEID_TYPE_64FLAG:
b0b0382b AV	106	fid64->parent_ino = XFS_I(parent)->i_ino;
b0b0382b AV	107	fid64->parent_gen = parent->i_generation;
c38344fe CH	108	/FALLTHRU/
c38344fe CH	109	case FILEID_INO32_GEN \| XFS_FILEID_TYPE_64FLAG:
c29f7d45	110	fid64->ino = XFS_I(inode)->i_ino;
c38344fe CH	111	fid64->gen = inode->i_generation;
c38344fe CH	112	break;
1da177e4	113	}
c38344fe CH	114
c38344fe CH	115	return fileid_type;
1da177e4 LT	116	}
1da177e4 LT	117
c38344fe CH	118	STATIC struct inode *
c38344fe CH	119	xfs_nfs_get_inode(
1da177e4	120	struct super_block *sb,
c38344fe CH	121	u64 ino,
	122	u32 generation)
	123	{
f71354bc CH	124	xfs_mount_t *mp = XFS_M(sb);
f71354bc CH	125	xfs_inode_t *ip;
1da177e4 LT	126	int error;
1da177e4 LT	127
f71354bc CH	128	/*
	129	* NFS can sometimes send requests for ino 0. Fail them gracefully.
	130	*/
	131	if (ino == 0)
	132	return ERR_PTR(-ESTALE);
1da177e4	133
c9a98553	134	/*
1920779e DC	135	* The XFS_IGET_UNTRUSTED means that an invalid inode number is just
	136	* fine and not an indication of a corrupted filesystem as clients can
	137	* send invalid file handles and we have to handle it gracefully..
c9a98553	138	*/
ef35e925	139	error = xfs_iget(mp, NULL, ino, XFS_IGET_UNTRUSTED, 0, &ip);
c9a98553 CH	140	if (error) {
	141	/*
	142	* EINVAL means the inode cluster doesn't exist anymore.
	143	* This implies the filehandle is stale, so we should
	144	* translate it here.
	145	* We don't use ESTALE directly down the chain to not
	146	* confuse applications using bulkstat that expect EINVAL.
	147	*/
ad1a2c87	148	if (error == EINVAL \|\| error == ENOENT)
c9a98553	149	error = ESTALE;
c38344fe	150	return ERR_PTR(-error);
c9a98553	151	}
f71354bc	152
6a7f422d	153	if (ip->i_d.di_gen != generation) {
ef35e925	154	IRELE(ip);
ad1a2c87	155	return ERR_PTR(-ESTALE);
f71354bc	156	}
c38344fe	157
01651646	158	return VFS_I(ip);
c38344fe CH	159	}
	160
	161	STATIC struct dentry *
	162	xfs_fs_fh_to_dentry(struct super_block sb, struct fid fid,
	163	int fh_len, int fileid_type)
	164	{
	165	struct xfs_fid64 fid64 = (struct xfs_fid64 )fid;
	166	struct inode *inode = NULL;
c38344fe CH	167
	168	if (fh_len < xfs_fileid_length(fileid_type))
	169	return NULL;
	170
	171	switch (fileid_type) {
	172	case FILEID_INO32_GEN_PARENT:
	173	case FILEID_INO32_GEN:
	174	inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen);
	175	break;
	176	case FILEID_INO32_GEN_PARENT \| XFS_FILEID_TYPE_64FLAG:
	177	case FILEID_INO32_GEN \| XFS_FILEID_TYPE_64FLAG:
	178	inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen);
	179	break;
	180	}
	181
44003728	182	return d_obtain_alias(inode);
c38344fe CH	183	}
	184
	185	STATIC struct dentry *
	186	xfs_fs_fh_to_parent(struct super_block sb, struct fid fid,
	187	int fh_len, int fileid_type)
	188	{
	189	struct xfs_fid64 fid64 = (struct xfs_fid64 )fid;
	190	struct inode *inode = NULL;
c38344fe	191
35c2a7f4 HD	192	if (fh_len < xfs_fileid_length(fileid_type))
	193	return NULL;
	194
c38344fe CH	195	switch (fileid_type) {
	196	case FILEID_INO32_GEN_PARENT:
	197	inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino,
	198	fid->i32.parent_gen);
	199	break;
	200	case FILEID_INO32_GEN_PARENT \| XFS_FILEID_TYPE_64FLAG:
	201	inode = xfs_nfs_get_inode(sb, fid64->parent_ino,
	202	fid64->parent_gen);
	203	break;
	204	}
	205
44003728	206	return d_obtain_alias(inode);
1da177e4 LT	207	}
	208
	209	STATIC struct dentry *
a50cd269	210	xfs_fs_get_parent(
1da177e4 LT	211	struct dentry *child)
	212	{
	213	int error;
ef1f5e7a	214	struct xfs_inode *cip;
1da177e4	215
384f3ced	216	error = xfs_lookup(XFS_I(child->d_inode), &xfs_name_dotdot, &cip, NULL);
1da177e4 LT	217	if (unlikely(error))
	218	return ERR_PTR(-error);
	219
44003728	220	return d_obtain_alias(VFS_I(cip));
1da177e4 LT	221	}
1da177e4 LT	222
978ebd97 BM	223	STATIC int
	224	xfs_fs_nfs_commit_metadata(
	225	struct inode *inode)
	226	{
	227	struct xfs_inode *ip = XFS_I(inode);
	228	struct xfs_mount *mp = ip->i_mount;
8292d88c	229	xfs_lsn_t lsn = 0;
978ebd97 BM	230
978ebd97 BM	231	xfs_ilock(ip, XFS_ILOCK_SHARED);
8292d88c CH	232	if (xfs_ipincount(ip))
8292d88c CH	233	lsn = ip->i_itemp->ili_last_lsn;
978ebd97 BM	234	xfs_iunlock(ip, XFS_ILOCK_SHARED);
978ebd97 BM	235
8292d88c CH	236	if (!lsn)
	237	return 0;
	238	return _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
978ebd97 BM	239	}
978ebd97 BM	240
39655164	241	const struct export_operations xfs_export_operations = {
a50cd269	242	.encode_fh = xfs_fs_encode_fh,
c38344fe CH	243	.fh_to_dentry = xfs_fs_fh_to_dentry,
c38344fe CH	244	.fh_to_parent = xfs_fs_fh_to_parent,
a50cd269	245	.get_parent = xfs_fs_get_parent,
978ebd97	246	.commit_metadata = xfs_fs_nfs_commit_metadata,
1da177e4	247	};