xfs: read and write metadata inode directory tree

Plumb in the bits we need to load metadata inodes from a named entry in
a metadir directory, create (or hardlink) inodes into a metadir
directory, create metadir directories, and flag inodes as being metadata
files.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2024-11-03 20:18:52 -08:00
parent 7297fd0beb
commit 5d9b54a4ef
8 changed files with 685 additions and 2 deletions

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@ -16,6 +16,7 @@ xfs-y += xfs_trace.o
xfs-y += $(addprefix libxfs/, \
xfs_group.o \
xfs_ag.o \
xfs_ag_resv.o \
xfs_alloc.o \
xfs_alloc_btree.o \
xfs_attr.o \
@ -43,7 +44,8 @@ xfs-y += $(addprefix libxfs/, \
xfs_inode_buf.o \
xfs_inode_util.o \
xfs_log_rlimit.o \
xfs_ag_resv.o \
xfs_metadir.o \
xfs_metafile.o \
xfs_parent.o \
xfs_rmap.o \
xfs_rmap_btree.o \

474
fs/xfs/libxfs/xfs_metadir.c Normal file
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@ -0,0 +1,474 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2018-2024 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_trans.h"
#include "xfs_metafile.h"
#include "xfs_metadir.h"
#include "xfs_trace.h"
#include "xfs_inode.h"
#include "xfs_quota.h"
#include "xfs_ialloc.h"
#include "xfs_bmap_btree.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_trans_space.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_parent.h"
/*
* Metadata Directory Tree
* =======================
*
* These functions provide an abstraction layer for looking up, creating, and
* deleting metadata inodes that live within a special metadata directory tree.
*
* This code does not manage the five existing metadata inodes: real time
* bitmap & summary; and the user, group, and quotas. All other metadata
* inodes must use only the xfs_meta{dir,file}_* functions.
*
* Callers wishing to create or hardlink a metadata inode must create an
* xfs_metadir_update structure, call the appropriate xfs_metadir* function,
* and then call xfs_metadir_commit or xfs_metadir_cancel to commit or cancel
* the update. Files in the metadata directory tree currently cannot be
* unlinked.
*
* When the metadir feature is enabled, all metadata inodes must have the
* "metadata" inode flag set to prevent them from being exposed to the outside
* world.
*
* Callers must take the ILOCK of any inode in the metadata directory tree to
* synchronize access to that inode. It is never necessary to take the IOLOCK
* or the MMAPLOCK since metadata inodes must not be exposed to user space.
*/
static inline void
xfs_metadir_set_xname(
struct xfs_name *xname,
const char *path,
unsigned char ftype)
{
xname->name = (const unsigned char *)path;
xname->len = strlen(path);
xname->type = ftype;
}
/*
* Given a parent directory @dp and a metadata inode path component @xname,
* Look up the inode number in the directory, returning it in @ino.
* @xname.type must match the directory entry's ftype.
*
* Caller must hold ILOCK_EXCL.
*/
static inline int
xfs_metadir_lookup(
struct xfs_trans *tp,
struct xfs_inode *dp,
struct xfs_name *xname,
xfs_ino_t *ino)
{
struct xfs_mount *mp = dp->i_mount;
struct xfs_da_args args = {
.trans = tp,
.dp = dp,
.geo = mp->m_dir_geo,
.name = xname->name,
.namelen = xname->len,
.hashval = xfs_dir2_hashname(mp, xname),
.whichfork = XFS_DATA_FORK,
.op_flags = XFS_DA_OP_OKNOENT,
.owner = dp->i_ino,
};
int error;
if (!S_ISDIR(VFS_I(dp)->i_mode))
return -EFSCORRUPTED;
if (xfs_is_shutdown(mp))
return -EIO;
error = xfs_dir_lookup_args(&args);
if (error)
return error;
if (!xfs_verify_ino(mp, args.inumber))
return -EFSCORRUPTED;
if (xname->type != XFS_DIR3_FT_UNKNOWN && xname->type != args.filetype)
return -EFSCORRUPTED;
trace_xfs_metadir_lookup(dp, xname, args.inumber);
*ino = args.inumber;
return 0;
}
/*
* Look up and read a metadata inode from the metadata directory. If the path
* component doesn't exist, return -ENOENT.
*/
int
xfs_metadir_load(
struct xfs_trans *tp,
struct xfs_inode *dp,
const char *path,
enum xfs_metafile_type metafile_type,
struct xfs_inode **ipp)
{
struct xfs_name xname;
xfs_ino_t ino;
int error;
xfs_metadir_set_xname(&xname, path, XFS_DIR3_FT_UNKNOWN);
xfs_ilock(dp, XFS_ILOCK_EXCL);
error = xfs_metadir_lookup(tp, dp, &xname, &ino);
xfs_iunlock(dp, XFS_ILOCK_EXCL);
if (error)
return error;
return xfs_trans_metafile_iget(tp, ino, metafile_type, ipp);
}
/*
* Unlock and release resources after committing (or cancelling) a metadata
* directory tree operation. The caller retains its reference to @upd->ip
* and must release it explicitly.
*/
static inline void
xfs_metadir_teardown(
struct xfs_metadir_update *upd,
int error)
{
trace_xfs_metadir_teardown(upd, error);
if (upd->ppargs) {
xfs_parent_finish(upd->dp->i_mount, upd->ppargs);
upd->ppargs = NULL;
}
if (upd->ip) {
if (upd->ip_locked)
xfs_iunlock(upd->ip, XFS_ILOCK_EXCL);
upd->ip_locked = false;
}
if (upd->dp_locked)
xfs_iunlock(upd->dp, XFS_ILOCK_EXCL);
upd->dp_locked = false;
}
/*
* Begin the process of creating a metadata file by allocating transactions
* and taking whatever resources we're going to need.
*/
int
xfs_metadir_start_create(
struct xfs_metadir_update *upd)
{
struct xfs_mount *mp = upd->dp->i_mount;
int error;
ASSERT(upd->dp != NULL);
ASSERT(upd->ip == NULL);
ASSERT(xfs_has_metadir(mp));
ASSERT(upd->metafile_type != XFS_METAFILE_UNKNOWN);
error = xfs_parent_start(mp, &upd->ppargs);
if (error)
return error;
/*
* If we ever need the ability to create rt metadata files on a
* pre-metadir filesystem, we'll need to dqattach the parent here.
* Currently we assume that mkfs will create the files and quotacheck
* will account for them.
*/
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_create,
xfs_create_space_res(mp, MAXNAMELEN), 0, 0, &upd->tp);
if (error)
goto out_teardown;
/*
* Lock the parent directory if there is one. We can't ijoin it to
* the transaction until after the child file has been created.
*/
xfs_ilock(upd->dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
upd->dp_locked = true;
trace_xfs_metadir_start_create(upd);
return 0;
out_teardown:
xfs_metadir_teardown(upd, error);
return error;
}
/*
* Create a metadata inode with the given @mode, and insert it into the
* metadata directory tree at the given @upd->path. The path up to the final
* component must already exist. The final path component must not exist.
*
* The new metadata inode will be attached to the update structure @upd->ip,
* with the ILOCK held until the caller releases it.
*
* NOTE: This function may return a new inode to the caller even if it returns
* a negative error code. If an inode is passed back, the caller must finish
* setting up the inode before releasing it.
*/
int
xfs_metadir_create(
struct xfs_metadir_update *upd,
umode_t mode)
{
struct xfs_icreate_args args = {
.pip = upd->dp,
.mode = mode,
};
struct xfs_name xname;
struct xfs_dir_update du = {
.dp = upd->dp,
.name = &xname,
.ppargs = upd->ppargs,
};
struct xfs_mount *mp = upd->dp->i_mount;
xfs_ino_t ino;
unsigned int resblks;
int error;
xfs_assert_ilocked(upd->dp, XFS_ILOCK_EXCL);
/* Check that the name does not already exist in the directory. */
xfs_metadir_set_xname(&xname, upd->path, XFS_DIR3_FT_UNKNOWN);
error = xfs_metadir_lookup(upd->tp, upd->dp, &xname, &ino);
switch (error) {
case -ENOENT:
break;
case 0:
error = -EEXIST;
fallthrough;
default:
return error;
}
/*
* A newly created regular or special file just has one directory
* entry pointing to them, but a directory also the "." entry
* pointing to itself.
*/
error = xfs_dialloc(&upd->tp, &args, &ino);
if (error)
return error;
error = xfs_icreate(upd->tp, ino, &args, &upd->ip);
if (error)
return error;
du.ip = upd->ip;
xfs_metafile_set_iflag(upd->tp, upd->ip, upd->metafile_type);
upd->ip_locked = true;
/*
* Join the directory inode to the transaction. We do not do it
* earlier because xfs_dialloc rolls the transaction.
*/
xfs_trans_ijoin(upd->tp, upd->dp, 0);
/* Create the entry. */
if (S_ISDIR(args.mode))
resblks = xfs_mkdir_space_res(mp, xname.len);
else
resblks = xfs_create_space_res(mp, xname.len);
xname.type = xfs_mode_to_ftype(args.mode);
trace_xfs_metadir_try_create(upd);
error = xfs_dir_create_child(upd->tp, resblks, &du);
if (error)
return error;
/* Metadir files are not accounted to quota. */
trace_xfs_metadir_create(upd);
return 0;
}
#ifndef __KERNEL__
/*
* Begin the process of linking a metadata file by allocating transactions
* and locking whatever resources we're going to need.
*/
int
xfs_metadir_start_link(
struct xfs_metadir_update *upd)
{
struct xfs_mount *mp = upd->dp->i_mount;
unsigned int resblks;
int nospace_error = 0;
int error;
ASSERT(upd->dp != NULL);
ASSERT(upd->ip != NULL);
ASSERT(xfs_has_metadir(mp));
error = xfs_parent_start(mp, &upd->ppargs);
if (error)
return error;
resblks = xfs_link_space_res(mp, MAXNAMELEN);
error = xfs_trans_alloc_dir(upd->dp, &M_RES(mp)->tr_link, upd->ip,
&resblks, &upd->tp, &nospace_error);
if (error)
goto out_teardown;
if (!resblks) {
/* We don't allow reservationless updates. */
xfs_trans_cancel(upd->tp);
upd->tp = NULL;
xfs_iunlock(upd->dp, XFS_ILOCK_EXCL);
xfs_iunlock(upd->ip, XFS_ILOCK_EXCL);
error = nospace_error;
goto out_teardown;
}
upd->dp_locked = true;
upd->ip_locked = true;
trace_xfs_metadir_start_link(upd);
return 0;
out_teardown:
xfs_metadir_teardown(upd, error);
return error;
}
/*
* Link the metadata directory given by @path to the inode @upd->ip.
* The path (up to the final component) must already exist, but the final
* component must not already exist.
*/
int
xfs_metadir_link(
struct xfs_metadir_update *upd)
{
struct xfs_name xname;
struct xfs_dir_update du = {
.dp = upd->dp,
.name = &xname,
.ip = upd->ip,
.ppargs = upd->ppargs,
};
struct xfs_mount *mp = upd->dp->i_mount;
xfs_ino_t ino;
unsigned int resblks;
int error;
xfs_assert_ilocked(upd->dp, XFS_ILOCK_EXCL);
xfs_assert_ilocked(upd->ip, XFS_ILOCK_EXCL);
/* Look up the name in the current directory. */
xfs_metadir_set_xname(&xname, upd->path,
xfs_mode_to_ftype(VFS_I(upd->ip)->i_mode));
error = xfs_metadir_lookup(upd->tp, upd->dp, &xname, &ino);
switch (error) {
case -ENOENT:
break;
case 0:
error = -EEXIST;
fallthrough;
default:
return error;
}
resblks = xfs_link_space_res(mp, xname.len);
error = xfs_dir_add_child(upd->tp, resblks, &du);
if (error)
return error;
trace_xfs_metadir_link(upd);
return 0;
}
#endif /* ! __KERNEL__ */
/* Commit a metadir update and unlock/drop all resources. */
int
xfs_metadir_commit(
struct xfs_metadir_update *upd)
{
int error;
trace_xfs_metadir_commit(upd);
error = xfs_trans_commit(upd->tp);
upd->tp = NULL;
xfs_metadir_teardown(upd, error);
return error;
}
/* Cancel a metadir update and unlock/drop all resources. */
void
xfs_metadir_cancel(
struct xfs_metadir_update *upd,
int error)
{
trace_xfs_metadir_cancel(upd);
xfs_trans_cancel(upd->tp);
upd->tp = NULL;
xfs_metadir_teardown(upd, error);
}
/* Create a metadata for the last component of the path. */
int
xfs_metadir_mkdir(
struct xfs_inode *dp,
const char *path,
struct xfs_inode **ipp)
{
struct xfs_metadir_update upd = {
.dp = dp,
.path = path,
.metafile_type = XFS_METAFILE_DIR,
};
int error;
if (xfs_is_shutdown(dp->i_mount))
return -EIO;
/* Allocate a transaction to create the last directory. */
error = xfs_metadir_start_create(&upd);
if (error)
return error;
/* Create the subdirectory and take our reference. */
error = xfs_metadir_create(&upd, S_IFDIR);
if (error)
goto out_cancel;
error = xfs_metadir_commit(&upd);
if (error)
goto out_irele;
xfs_finish_inode_setup(upd.ip);
*ipp = upd.ip;
return 0;
out_cancel:
xfs_metadir_cancel(&upd, error);
out_irele:
/* Have to finish setting up the inode to ensure it's deleted. */
if (upd.ip) {
xfs_finish_inode_setup(upd.ip);
xfs_irele(upd.ip);
}
return error;
}

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@ -0,0 +1,47 @@
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (c) 2018-2024 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#ifndef __XFS_METADIR_H__
#define __XFS_METADIR_H__
/* Cleanup widget for metadata inode creation and deletion. */
struct xfs_metadir_update {
/* Parent directory */
struct xfs_inode *dp;
/* Path to metadata file */
const char *path;
/* Parent pointer update context */
struct xfs_parent_args *ppargs;
/* Child metadata file */
struct xfs_inode *ip;
struct xfs_trans *tp;
enum xfs_metafile_type metafile_type;
unsigned int dp_locked:1;
unsigned int ip_locked:1;
};
int xfs_metadir_load(struct xfs_trans *tp, struct xfs_inode *dp,
const char *path, enum xfs_metafile_type metafile_type,
struct xfs_inode **ipp);
int xfs_metadir_start_create(struct xfs_metadir_update *upd);
int xfs_metadir_create(struct xfs_metadir_update *upd, umode_t mode);
int xfs_metadir_start_link(struct xfs_metadir_update *upd);
int xfs_metadir_link(struct xfs_metadir_update *upd);
int xfs_metadir_commit(struct xfs_metadir_update *upd);
void xfs_metadir_cancel(struct xfs_metadir_update *upd, int error);
int xfs_metadir_mkdir(struct xfs_inode *dp, const char *path,
struct xfs_inode **ipp);
#endif /* __XFS_METADIR_H__ */

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@ -0,0 +1,52 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2018-2024 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_trans.h"
#include "xfs_metafile.h"
#include "xfs_trace.h"
#include "xfs_inode.h"
/* Set up an inode to be recognized as a metadata directory inode. */
void
xfs_metafile_set_iflag(
struct xfs_trans *tp,
struct xfs_inode *ip,
enum xfs_metafile_type metafile_type)
{
VFS_I(ip)->i_mode &= ~0777;
VFS_I(ip)->i_uid = GLOBAL_ROOT_UID;
VFS_I(ip)->i_gid = GLOBAL_ROOT_GID;
if (S_ISDIR(VFS_I(ip)->i_mode))
ip->i_diflags |= XFS_METADIR_DIFLAGS;
else
ip->i_diflags |= XFS_METAFILE_DIFLAGS;
ip->i_diflags2 &= ~XFS_DIFLAG2_DAX;
ip->i_diflags2 |= XFS_DIFLAG2_METADATA;
ip->i_metatype = metafile_type;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
}
/* Clear the metadata directory inode flag. */
void
xfs_metafile_clear_iflag(
struct xfs_trans *tp,
struct xfs_inode *ip)
{
ASSERT(xfs_is_metadir_inode(ip));
ASSERT(VFS_I(ip)->i_nlink == 0);
ip->i_diflags2 &= ~XFS_DIFLAG2_METADATA;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
}

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@ -17,6 +17,10 @@
#define XFS_METADIR_DIFLAGS (XFS_METAFILE_DIFLAGS | \
XFS_DIFLAG_NOSYMLINKS)
void xfs_metafile_set_iflag(struct xfs_trans *tp, struct xfs_inode *ip,
enum xfs_metafile_type metafile_type);
void xfs_metafile_clear_iflag(struct xfs_trans *tp, struct xfs_inode *ip);
/* Code specific to kernel/userspace; must be provided externally. */
int xfs_trans_metafile_iget(struct xfs_trans *tp, xfs_ino_t ino,

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@ -850,7 +850,7 @@ xfs_trans_metafile_iget(
int error;
error = xfs_iget(mp, tp, ino, 0, 0, &ip);
if (error == -EFSCORRUPTED)
if (error == -EFSCORRUPTED || error == -EINVAL)
goto whine;
if (error)
return error;

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@ -46,6 +46,8 @@
#include "xfs_parent.h"
#include "xfs_rmap.h"
#include "xfs_refcount.h"
#include "xfs_metafile.h"
#include "xfs_metadir.h"
/*
* We include this last to have the helpers above available for the trace

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@ -95,6 +95,7 @@ struct xfs_attrlist_cursor_kern;
struct xfs_extent_free_item;
struct xfs_rmap_intent;
struct xfs_refcount_intent;
struct xfs_metadir_update;
#define XFS_ATTR_FILTER_FLAGS \
{ XFS_ATTR_ROOT, "ROOT" }, \
@ -5352,6 +5353,107 @@ DEFINE_EVENT(xfs_getparents_class, name, \
DEFINE_XFS_GETPARENTS_EVENT(xfs_getparents_begin);
DEFINE_XFS_GETPARENTS_EVENT(xfs_getparents_end);
DECLARE_EVENT_CLASS(xfs_metadir_update_class,
TP_PROTO(const struct xfs_metadir_update *upd),
TP_ARGS(upd),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(xfs_ino_t, dp_ino)
__field(xfs_ino_t, ino)
__string(fname, upd->path)
),
TP_fast_assign(
__entry->dev = upd->dp->i_mount->m_super->s_dev;
__entry->dp_ino = upd->dp->i_ino;
__entry->ino = upd->ip ? upd->ip->i_ino : NULLFSINO;
__assign_str(fname);
),
TP_printk("dev %d:%d dp 0x%llx fname '%s' ino 0x%llx",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->dp_ino,
__get_str(fname),
__entry->ino)
)
#define DEFINE_METADIR_UPDATE_EVENT(name) \
DEFINE_EVENT(xfs_metadir_update_class, name, \
TP_PROTO(const struct xfs_metadir_update *upd), \
TP_ARGS(upd))
DEFINE_METADIR_UPDATE_EVENT(xfs_metadir_start_create);
DEFINE_METADIR_UPDATE_EVENT(xfs_metadir_start_link);
DEFINE_METADIR_UPDATE_EVENT(xfs_metadir_commit);
DEFINE_METADIR_UPDATE_EVENT(xfs_metadir_cancel);
DEFINE_METADIR_UPDATE_EVENT(xfs_metadir_try_create);
DEFINE_METADIR_UPDATE_EVENT(xfs_metadir_create);
DEFINE_METADIR_UPDATE_EVENT(xfs_metadir_link);
DECLARE_EVENT_CLASS(xfs_metadir_update_error_class,
TP_PROTO(const struct xfs_metadir_update *upd, int error),
TP_ARGS(upd, error),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(xfs_ino_t, dp_ino)
__field(xfs_ino_t, ino)
__field(int, error)
__string(fname, upd->path)
),
TP_fast_assign(
__entry->dev = upd->dp->i_mount->m_super->s_dev;
__entry->dp_ino = upd->dp->i_ino;
__entry->ino = upd->ip ? upd->ip->i_ino : NULLFSINO;
__entry->error = error;
__assign_str(fname);
),
TP_printk("dev %d:%d dp 0x%llx fname '%s' ino 0x%llx error %d",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->dp_ino,
__get_str(fname),
__entry->ino,
__entry->error)
)
#define DEFINE_METADIR_UPDATE_ERROR_EVENT(name) \
DEFINE_EVENT(xfs_metadir_update_error_class, name, \
TP_PROTO(const struct xfs_metadir_update *upd, int error), \
TP_ARGS(upd, error))
DEFINE_METADIR_UPDATE_ERROR_EVENT(xfs_metadir_teardown);
DECLARE_EVENT_CLASS(xfs_metadir_class,
TP_PROTO(struct xfs_inode *dp, struct xfs_name *name,
xfs_ino_t ino),
TP_ARGS(dp, name, ino),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(xfs_ino_t, dp_ino)
__field(xfs_ino_t, ino)
__field(int, ftype)
__field(int, namelen)
__dynamic_array(char, name, name->len)
),
TP_fast_assign(
__entry->dev = VFS_I(dp)->i_sb->s_dev;
__entry->dp_ino = dp->i_ino;
__entry->ino = ino,
__entry->ftype = name->type;
__entry->namelen = name->len;
memcpy(__get_str(name), name->name, name->len);
),
TP_printk("dev %d:%d dir 0x%llx type %s name '%.*s' ino 0x%llx",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->dp_ino,
__print_symbolic(__entry->ftype, XFS_DIR3_FTYPE_STR),
__entry->namelen,
__get_str(name),
__entry->ino)
)
#define DEFINE_METADIR_EVENT(name) \
DEFINE_EVENT(xfs_metadir_class, name, \
TP_PROTO(struct xfs_inode *dp, struct xfs_name *name, \
xfs_ino_t ino), \
TP_ARGS(dp, name, ino))
DEFINE_METADIR_EVENT(xfs_metadir_lookup);
#endif /* _TRACE_XFS_H */
#undef TRACE_INCLUDE_PATH