From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
This is a, um, "sample" implementation of parent pointers that abuses
struct dentry to return one parent pointer of a file ... if the dentry
cache has been connected. This exists only to enable testing of the
userspace xfs_scrub bits and is probably too ugly to live. Wait for the
real implementation.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/Makefile | 1
fs/xfs/libxfs/xfs_fs.h | 57 +++++++++++++
fs/xfs/xfs_ioctl.c | 49 +++++++++++
fs/xfs/xfs_parent.c | 214 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_parent.h | 29 +++++++
5 files changed, 350 insertions(+)
create mode 100644 fs/xfs/xfs_parent.c
create mode 100644 fs/xfs/xfs_parent.h
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index e1768e7..9f4de14 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -99,6 +99,7 @@ xfs-y += xfs_aops.o \
xfs_message.o \
xfs_mount.o \
xfs_mru_cache.o \
+ xfs_parent.o \
xfs_reflink.o \
xfs_stats.o \
xfs_super.o \
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index fc4386a..f0ff964 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -545,6 +545,62 @@ struct xfs_scrub_metadata {
XFS_SCRUB_OFLAG_WARNING)
#define XFS_SCRUB_FLAGS_ALL (XFS_SCRUB_FLAGS_IN | XFS_SCRUB_FLAGS_OUT)
+/* Parent Pointers */
+#define XFS_PPTR_NAME_MAX 256
+
+struct xfs_pptr {
+ /* Parent inode number. */
+ __u64 pp_ino;
+ __u64 pp_reserved[2];
+
+ /* Parent generation number. */
+ __u32 pp_gen;
+
+ /* Name in the parent. */
+ __u32 pp_namelen;
+ __u8 pp_name[XFS_PPTR_NAME_MAX];
+};
+
+/* return parents of the handle, not the open fd */
+#define XFS_PPTR_IFLAG_HANDLE (1U << 0)
+
+#define XFS_PPTR_ALL_IFLAGS (XFS_PPTR_IFLAG_HANDLE)
+
+/* partial results only */
+#define XFS_PPTR_OFLAG_PARTIAL (1U << 0)
+
+/* target was the root directory */
+#define XFS_PPTR_OFLAG_ROOT (1U << 1)
+
+struct xfs_pptr_info {
+ /* i: (optional) file handle. */
+ struct xfs_handle pi_handle;
+
+ /* i/o: xattr lookup cursor, if necessary */
+ struct xfs_attrlist_cursor pi_cursor;
+
+ /* i: input flags */
+ __u32 pi_iflags;
+
+ /* o: output flags */
+ __u32 pi_oflags;
+
+ /* i: number of pointers we have space for. */
+ __u32 pi_ptrs_size;
+
+ /* o: number of pointers actually returned. */
+ __u32 pi_ptrs_used;
+
+ /* must be zero */
+ __u64 pi_reserved[6];
+
+ /* o: pointer info, must come last */
+ struct xfs_pptr pi_ptrs[0];
+};
+
+#define XFS_PPTR_INFO_SIZEOF(nr_ptrs) (sizeof(struct xfs_pptr_info) + \
+ ((nr_ptrs) * sizeof(struct xfs_pptr)))
+
/*
* ioctl limits
*/
@@ -589,6 +645,7 @@ struct xfs_scrub_metadata {
#define XFS_IOC_FREE_EOFBLOCKS _IOR ('X', 58, struct xfs_fs_eofblocks)
/* XFS_IOC_GETFSMAP ------ hoisted 59 */
#define XFS_IOC_SCRUB_METADATA _IOWR('X', 60, struct xfs_scrub_metadata)
+#define XFS_IOC_GET_PPTR _IOWR('X', 61, struct xfs_pptr_info)
/*
* ioctl commands that replace IRIX syssgi()'s
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 20dc65f..916b060 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -45,6 +45,7 @@
#include <linux/fsmap.h>
#include "xfs_fsmap.h"
#include "scrub/xfs_scrub.h"
+#include "xfs_parent.h"
#include <linux/capability.h>
#include <linux/cred.h>
@@ -1730,6 +1731,51 @@ xfs_ioc_scrub_metadata(
return 0;
}
+struct getpptr_info {
+ struct xfs_pptr_info __user *data;
+ unsigned int idx;
+};
+
+STATIC int
+xfs_getpptr_format(
+ struct xfs_pptr *pp,
+ void *arg)
+{
+ struct getpptr_info *info = arg;
+
+ if (copy_to_user(&info->data->pi_ptrs[info->idx++], pp,
+ sizeof(struct xfs_pptr)))
+ return -EFAULT;
+ return 0;
+}
+
+STATIC int
+xfs_ioc_get_parent_pointers(
+ struct file *filp,
+ void __user *arg)
+{
+ struct getpptr_info info = { NULL };
+ struct xfs_pptr_info pi;
+ int error;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (copy_from_user(&pi, arg, sizeof(pi)))
+ return -EFAULT;
+
+ info.data = arg;
+ error = xfs_parent_get_pointers(filp, &pi, xfs_getpptr_format, &info);
+ if (error)
+ return error;
+
+ pi.pi_ptrs_used = info.idx;
+ if (copy_to_user(arg, &pi, sizeof(pi)))
+ return -EFAULT;
+
+ return 0;
+}
+
int
xfs_ioc_swapext(
xfs_swapext_t *sxp)
@@ -1914,6 +1960,9 @@ xfs_file_ioctl(
case XFS_IOC_SCRUB_METADATA:
return xfs_ioc_scrub_metadata(ip, arg);
+ case XFS_IOC_GET_PPTR:
+ return xfs_ioc_get_parent_pointers(filp, arg);
+
case XFS_IOC_FD_TO_HANDLE:
case XFS_IOC_PATH_TO_HANDLE:
case XFS_IOC_PATH_TO_FSHANDLE: {
diff --git a/fs/xfs/xfs_parent.c b/fs/xfs/xfs_parent.c
new file mode 100644
index 0000000..91b07e0
--- /dev/null
+++ b/fs/xfs/xfs_parent.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (C) 2017 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ *
+ * 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; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_icache.h"
+#include "xfs_itable.h"
+#include "xfs_export.h"
+#include "xfs_parent.h"
+
+struct xfs_pptr_buf {
+ uint32_t idx;
+ struct xfs_pptr recs[0];
+};
+
+#define XFS_PARENT_ITER_ABORT (1)
+
+/* Package up a pptr structure and emit it to the caller. */
+static int
+xfs_parent_emit(
+ struct xfs_pptr_info *pi,
+ struct xfs_pptr_buf *pb,
+ uint64_t ino,
+ uint32_t gen,
+ uint8_t namelen,
+ const char *name)
+{
+ struct xfs_pptr *pptr;
+
+ if (pb->idx >= pi->pi_ptrs_size)
+ return XFS_PARENT_ITER_ABORT;
+
+ pptr = &pb->recs[pb->idx++];
+ pptr->pp_ino = ino;
+ pptr->pp_gen = gen;
+ pptr->pp_namelen = namelen;
+ memcpy(pptr->pp_name, name, namelen);
+
+ return 0;
+}
+
+/*
+ * No need to do permission checks on the various pathname components
+ * as the handle operations are privileged.
+ */
+STATIC int
+xfs_parent_handle_acceptable(
+ void *context,
+ struct dentry *dentry)
+{
+ return 1;
+}
+
+/* Get parent info for an inode by walking the parent dentry. */
+static int
+xfs_parent_get_dparent(
+ struct file *filp,
+ struct xfs_pptr_info *pi,
+ struct xfs_pptr_buf *pb)
+{
+ struct xfs_inode *ip;
+ struct inode *dir_inode;
+ struct dentry *dentry;
+ struct dentry *dparent;
+ unsigned int ilock;
+ int error = 0;
+
+ pi->pi_oflags |= XFS_PPTR_OFLAG_PARTIAL;
+
+ /* Any nonzero byte in the cursor means we've already retrieved one. */
+ if (memchr_inv(&pi->pi_cursor, 0, sizeof(pi->pi_cursor)))
+ return 0;
+ memset(&pi->pi_cursor, 0xFF, sizeof(pi->pi_cursor));
+
+ if (pi->pi_iflags & XFS_PPTR_IFLAG_HANDLE) {
+ struct xfs_handle *handle = &pi->pi_handle;
+ struct xfs_fid64 fid = { 0 };
+
+ /* Extract the desired file from the handle info. */
+ if (sizeof(handle->ha_fid) - sizeof(handle->ha_fid.fid_len) !=
+ handle->ha_fid.fid_len)
+ return -EINVAL;
+
+ fid.ino = handle->ha_fid.fid_ino;
+ fid.gen = handle->ha_fid.fid_gen;
+
+ dentry = exportfs_decode_fh(filp->f_path.mnt,
+ (struct fid *)&fid, 3,
+ FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG,
+ xfs_parent_handle_acceptable, NULL);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ } else {
+ /* Or just use the dentry of the open file. */
+ dentry = dget(file_dentry(filp));
+ }
+
+ /* Lock XFS inode... */
+ ip = XFS_I(d_inode(dentry));
+ ilock = XFS_IOLOCK_SHARED | XFS_MMAPLOCK_SHARED | XFS_ILOCK_SHARED;
+ xfs_ilock(ip, ilock);
+
+ /* Bail out early for the root dir. */
+ if (ip->i_ino == ip->i_mount->m_sb.sb_rootino) {
+ pi->pi_oflags |= XFS_PPTR_OFLAG_ROOT;
+ goto out_dentry;
+ }
+
+ /* Filter out the unconnected inodes. */
+ if (d_unlinked(dentry) || (dentry->d_flags & DCACHE_DISCONNECTED))
+ goto out_dentry;
+ if (IS_ROOT(dentry)) {
+ pi->pi_oflags |= XFS_PPTR_OFLAG_ROOT;
+ goto out_dentry;
+ }
+
+ /* Otherwise look up the parent... */
+ dparent = dget_parent(dentry);
+ if (IS_ERR(dparent)) {
+ error = PTR_ERR(dparent);
+ goto out_dentry;
+ }
+
+ dir_inode = d_inode(dparent);
+ if (!dir_inode)
+ goto out_dparent;
+
+ /* ...and emit a record. */
+ error = xfs_parent_emit(pi, pb, dir_inode->i_ino,
+ dir_inode->i_generation,
+ ACCESS_ONCE(dentry->d_name.len),
+ ACCESS_ONCE(dentry->d_name.name));
+ if (error == XFS_PARENT_ITER_ABORT)
+ error = 0;
+
+out_dparent:
+ dput(dparent);
+out_dentry:
+ xfs_iunlock(ip, ilock);
+ dput(dentry);
+ return error;
+}
+
+/* Walk all the parent pointers of a file. */
+int
+xfs_parent_get_pointers(
+ struct file *filp,
+ struct xfs_pptr_info *pi,
+ xfs_parent_format_t formatter,
+ void *arg)
+{
+ struct xfs_pptr_buf *pb;
+ size_t sz;
+ unsigned int i;
+ int error;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (pi->pi_iflags & ~XFS_PPTR_ALL_IFLAGS)
+ return -EINVAL;
+ if (memchr_inv(pi->pi_reserved, 0, sizeof(pi->pi_reserved)))
+ return -EINVAL;
+
+ /*
+ * Allocate temporary buffer to hold pptr records while we have
+ * the inode locked.
+ */
+ sz = sizeof(struct xfs_pptr_buf) +
+ (pi->pi_ptrs_size * sizeof(struct xfs_pptr));
+ if (sz > PAGE_SIZE * 4)
+ return -ENOMEM;
+ pb = kmem_zalloc_large(sz, KM_SLEEP | KM_MAYFAIL);
+ if (!pb)
+ return -ENOMEM;
+
+ /* Record parent pointer information in buffer. */
+ error = xfs_parent_get_dparent(filp, pi, pb);
+ if (error)
+ goto out;
+
+ /* Format records to userspace. */
+ for (i = 0; error == 0 && i < pb->idx; i++)
+ error = formatter(&pb->recs[i], arg);
+
+out:
+ kmem_free(pb);
+ return error;
+}
diff --git a/fs/xfs/xfs_parent.h b/fs/xfs/xfs_parent.h
new file mode 100644
index 0000000..23ee505
--- /dev/null
+++ b/fs/xfs/xfs_parent.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ *
+ * 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; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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.
+ */
+#ifndef __XFS_PARENT_H__
+#define __XFS_PARENT_H__
+
+/* pptr to userspace formatter - copy to user & advance pointer */
+typedef int (*xfs_parent_format_t)(struct xfs_pptr *, void *);
+
+int xfs_parent_get_pointers(struct file *filp, struct xfs_pptr_info *pi,
+ xfs_parent_format_t formatter, void *priv);
+
+#endif /* __XFS_PARENT_H__ */
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