From: Allison Henderson <allison.henderson@xxxxxxxxxx>
This patch adds a new file ioctl to retrieve the parent pointer of a
given inode
Signed-off-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
---
fs/xfs/Makefile | 1 +
fs/xfs/libxfs/xfs_fs.h | 74 ++++++++++++++++++++++
fs/xfs/libxfs/xfs_parent.c | 10 +++
fs/xfs/libxfs/xfs_parent.h | 2 +
fs/xfs/xfs_ioctl.c | 94 ++++++++++++++++++++++++++-
fs/xfs/xfs_ondisk.h | 4 ++
fs/xfs/xfs_parent_utils.c | 126 +++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_parent_utils.h | 11 ++++
8 files changed, 321 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index e2b2cf50ffcf..42d0496fdad7 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -86,6 +86,7 @@ xfs-y += xfs_aops.o \
xfs_mount.o \
xfs_mru_cache.o \
xfs_pwork.o \
+ xfs_parent_utils.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 b0b4d7a3aa15..9e59a1fdfb0c 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -752,6 +752,79 @@ struct xfs_scrub_metadata {
XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED)
#define XFS_SCRUB_FLAGS_ALL (XFS_SCRUB_FLAGS_IN | XFS_SCRUB_FLAGS_OUT)
+#define XFS_PPTR_MAXNAMELEN 256
+
+/* return parents of the handle, not the open fd */
+#define XFS_PPTR_IFLAG_HANDLE (1U << 0)
+
+/* target was the root directory */
+#define XFS_PPTR_OFLAG_ROOT (1U << 1)
+
+/* Cursor is done iterating pptrs */
+#define XFS_PPTR_OFLAG_DONE (1U << 2)
+
+ #define XFS_PPTR_FLAG_ALL (XFS_PPTR_IFLAG_HANDLE | XFS_PPTR_OFLAG_ROOT | \
+ XFS_PPTR_OFLAG_DONE)
+
+/* Get an inode parent pointer through ioctl */
+struct xfs_parent_ptr {
+ __u64 xpp_ino; /* Inode */
+ __u32 xpp_gen; /* Inode generation */
+ __u32 xpp_diroffset; /* Directory offset */
+ __u64 xpp_rsvd; /* Reserved */
+ __u8 xpp_name[XFS_PPTR_MAXNAMELEN]; /* File name */
+};
+
+/* Iterate through an inodes parent pointers */
+struct xfs_pptr_info {
+ /* File handle, if XFS_PPTR_IFLAG_HANDLE is set */
+ struct xfs_handle pi_handle;
+
+ /*
+ * Structure to track progress in iterating the parent pointers.
+ * Must be initialized to zeroes before the first ioctl call, and
+ * not touched by callers after that.
+ */
+ struct xfs_attrlist_cursor pi_cursor;
+
+ /* Operational flags: XFS_PPTR_*FLAG* */
+ __u32 pi_flags;
+
+ /* Must be set to zero */
+ __u32 pi_reserved;
+
+ /* # of entries in array */
+ __u32 pi_ptrs_size;
+
+ /* # of entries filled in (output) */
+ __u32 pi_ptrs_used;
+
+ /* Must be set to zero */
+ __u64 pi_reserved2[6];
+
+ /*
+ * An array of struct xfs_parent_ptr follows the header
+ * information. Use xfs_ppinfo_to_pp() to access the
+ * parent pointer array entries.
+ */
+ struct xfs_parent_ptr pi_parents[];
+};
+
+static inline size_t
+xfs_pptr_info_sizeof(int nr_ptrs)
+{
+ return sizeof(struct xfs_pptr_info) +
+ (nr_ptrs * sizeof(struct xfs_parent_ptr));
+}
+
+static inline struct xfs_parent_ptr*
+xfs_ppinfo_to_pp(
+ struct xfs_pptr_info *info,
+ int idx)
+{
+ return &info->pi_parents[idx];
+}
+
/*
* ioctl limits
*/
@@ -797,6 +870,7 @@ struct xfs_scrub_metadata {
/* XFS_IOC_GETFSMAP ------ hoisted 59 */
#define XFS_IOC_SCRUB_METADATA _IOWR('X', 60, struct xfs_scrub_metadata)
#define XFS_IOC_AG_GEOMETRY _IOWR('X', 61, struct xfs_ag_geometry)
+#define XFS_IOC_GETPARENTS _IOWR('X', 62, struct xfs_parent_ptr)
/*
* ioctl commands that replace IRIX syssgi()'s
diff --git a/fs/xfs/libxfs/xfs_parent.c b/fs/xfs/libxfs/xfs_parent.c
index 954a52d6be00..fa3d645731a9 100644
--- a/fs/xfs/libxfs/xfs_parent.c
+++ b/fs/xfs/libxfs/xfs_parent.c
@@ -27,6 +27,16 @@
#include "xfs_parent.h"
#include "xfs_trans_space.h"
+/* Initializes a xfs_parent_ptr from an xfs_parent_name_rec */
+void
+xfs_init_parent_ptr(struct xfs_parent_ptr *xpp,
+ const struct xfs_parent_name_rec *rec)
+{
+ xpp->xpp_ino = be64_to_cpu(rec->p_ino);
+ xpp->xpp_gen = be32_to_cpu(rec->p_gen);
+ xpp->xpp_diroffset = be32_to_cpu(rec->p_diroffset);
+}
+
/*
* Parent pointer attribute handling.
*
diff --git a/fs/xfs/libxfs/xfs_parent.h b/fs/xfs/libxfs/xfs_parent.h
index 9021241ad65b..898842b4532d 100644
--- a/fs/xfs/libxfs/xfs_parent.h
+++ b/fs/xfs/libxfs/xfs_parent.h
@@ -24,6 +24,8 @@ void xfs_init_parent_name_rec(struct xfs_parent_name_rec *rec,
uint32_t p_diroffset);
void xfs_init_parent_name_irec(struct xfs_parent_name_irec *irec,
struct xfs_parent_name_rec *rec);
+void xfs_init_parent_ptr(struct xfs_parent_ptr *xpp,
+ const struct xfs_parent_name_rec *rec);
int xfs_parent_init(xfs_mount_t *mp, struct xfs_parent_defer **parentp);
int xfs_parent_defer_add(struct xfs_trans *tp, struct xfs_parent_defer *parent,
struct xfs_inode *dp, struct xfs_name *parent_name,
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 5cd5154d4d1e..df5a45b97f8f 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -37,6 +37,7 @@
#include "xfs_health.h"
#include "xfs_reflink.h"
#include "xfs_ioctl.h"
+#include "xfs_parent_utils.h"
#include "xfs_xattr.h"
#include <linux/mount.h>
@@ -1675,6 +1676,96 @@ xfs_ioc_scrub_metadata(
return 0;
}
+/*
+ * IOCTL routine to get the parent pointers of an inode and return it to user
+ * space. Caller must pass a buffer space containing a struct xfs_pptr_info,
+ * followed by a region large enough to contain an array of struct
+ * xfs_parent_ptr of a size specified in pi_ptrs_size. If the inode contains
+ * more parent pointers than can fit in the buffer space, caller may re-call
+ * the function using the returned pi_cursor to resume iteration. The
+ * number of xfs_parent_ptr returned will be stored in pi_ptrs_used.
+ *
+ * Returns 0 on success or non-zero on failure
+ */
+STATIC int
+xfs_ioc_get_parent_pointer(
+ struct file *filp,
+ void __user *arg)
+{
+ struct xfs_pptr_info *ppi = NULL;
+ int error = 0;
+ struct xfs_inode *ip = XFS_I(file_inode(filp));
+ struct xfs_mount *mp = ip->i_mount;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* Allocate an xfs_pptr_info to put the user data */
+ ppi = kmalloc(sizeof(struct xfs_pptr_info), 0);
+ if (!ppi)
+ return -ENOMEM;
+
+ /* Copy the data from the user */
+ error = copy_from_user(ppi, arg, sizeof(struct xfs_pptr_info));
+ if (error) {
+ error = -EFAULT;
+ goto out;
+ }
+
+ /* Check size of buffer requested by user */
+ if (xfs_pptr_info_sizeof(ppi->pi_ptrs_size) > XFS_XATTR_LIST_MAX) {
+ error = -ENOMEM;
+ goto out;
+ }
+
+ if (ppi->pi_flags & ~XFS_PPTR_FLAG_ALL) {
+ error = -EINVAL;
+ goto out;
+ }
+ ppi->pi_flags &= ~(XFS_PPTR_OFLAG_ROOT | XFS_PPTR_OFLAG_DONE);
+
+ /*
+ * Now that we know how big the trailing buffer is, expand
+ * our kernel xfs_pptr_info to be the same size
+ */
+ ppi = krealloc(ppi, xfs_pptr_info_sizeof(ppi->pi_ptrs_size), 0);
+ if (!ppi)
+ return -ENOMEM;
+
+ if (ppi->pi_flags & XFS_PPTR_IFLAG_HANDLE) {
+ error = xfs_iget(mp, NULL, ppi->pi_handle.ha_fid.fid_ino,
+ 0, 0, &ip);
+ if (error)
+ goto out;
+
+ if (VFS_I(ip)->i_generation != ppi->pi_handle.ha_fid.fid_gen) {
+ error = -EINVAL;
+ goto out;
+ }
+ }
+
+ if (ip->i_ino == mp->m_sb.sb_rootino)
+ ppi->pi_flags |= XFS_PPTR_OFLAG_ROOT;
+
+ /* Get the parent pointers */
+ error = xfs_attr_get_parent_pointer(ip, ppi);
+
+ if (error)
+ goto out;
+
+ /* Copy the parent pointers back to the user */
+ error = copy_to_user(arg, ppi,
+ xfs_pptr_info_sizeof(ppi->pi_ptrs_size));
+ if (error) {
+ error = -EFAULT;
+ goto out;
+ }
+
+out:
+ kmem_free(ppi);
+ return error;
+}
+
int
xfs_ioc_swapext(
xfs_swapext_t *sxp)
@@ -1964,7 +2055,8 @@ xfs_file_ioctl(
case XFS_IOC_FSGETXATTRA:
return xfs_ioc_fsgetxattra(ip, arg);
-
+ case XFS_IOC_GETPARENTS:
+ return xfs_ioc_get_parent_pointer(filp, arg);
case XFS_IOC_GETBMAP:
case XFS_IOC_GETBMAPA:
case XFS_IOC_GETBMAPX:
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 9737b5a9f405..6a6bd05c2a68 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -150,6 +150,10 @@ xfs_check_ondisk_structs(void)
XFS_CHECK_OFFSET(struct xfs_efi_log_format_32, efi_extents, 16);
XFS_CHECK_OFFSET(struct xfs_efi_log_format_64, efi_extents, 16);
+ /* parent pointer ioctls */
+ XFS_CHECK_STRUCT_SIZE(struct xfs_parent_ptr, 280);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_pptr_info, 104);
+
/*
* The v5 superblock format extended several v4 header structures with
* additional data. While new fields are only accessible on v5
diff --git a/fs/xfs/xfs_parent_utils.c b/fs/xfs/xfs_parent_utils.c
new file mode 100644
index 000000000000..771279731d42
--- /dev/null
+++ b/fs/xfs/xfs_parent_utils.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Oracle, Inc.
+ * All rights reserved.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_shared.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_inode.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_trans.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_attr.h"
+#include "xfs_ioctl.h"
+#include "xfs_parent.h"
+#include "xfs_da_btree.h"
+#include "xfs_parent_utils.h"
+
+/*
+ * Get the parent pointers for a given inode
+ *
+ * Returns 0 on success and non zero on error
+ */
+int
+xfs_attr_get_parent_pointer(
+ struct xfs_inode *ip,
+ struct xfs_pptr_info *ppi)
+{
+
+ struct xfs_attrlist *alist;
+ struct xfs_attrlist_ent *aent;
+ struct xfs_parent_ptr *xpp;
+ struct xfs_parent_name_rec *xpnr;
+ char *namebuf;
+ unsigned int namebuf_size;
+ int name_len, i, error = 0;
+ unsigned int lock_mode, flags = XFS_ATTR_PARENT;
+ struct xfs_attr_list_context context;
+
+ /* Allocate a buffer to store the attribute names */
+ namebuf_size = sizeof(struct xfs_attrlist) +
+ (ppi->pi_ptrs_size) * sizeof(struct xfs_attrlist_ent);
+ namebuf = kvzalloc(namebuf_size, GFP_KERNEL);
+ if (!namebuf)
+ return -ENOMEM;
+
+ memset(&context, 0, sizeof(struct xfs_attr_list_context));
+ error = xfs_ioc_attr_list_context_init(ip, namebuf, namebuf_size, 0,
+ &context);
+ if (error)
+ goto out_kfree;
+
+ /* Copy the cursor provided by caller */
+ memcpy(&context.cursor, &ppi->pi_cursor,
+ sizeof(struct xfs_attrlist_cursor));
+ context.attr_filter = XFS_ATTR_PARENT;
+
+ lock_mode = xfs_ilock_attr_map_shared(ip);
+
+ error = xfs_attr_list_ilocked(&context);
+ if (error)
+ goto out_unlock;
+
+ alist = (struct xfs_attrlist *)namebuf;
+ for (i = 0; i < alist->al_count; i++) {
+ struct xfs_da_args args = {
+ .geo = ip->i_mount->m_attr_geo,
+ .whichfork = XFS_ATTR_FORK,
+ .dp = ip,
+ .namelen = sizeof(struct xfs_parent_name_rec),
+ .attr_filter = flags,
+ };
+
+ xpp = xfs_ppinfo_to_pp(ppi, i);
+ memset(xpp, 0, sizeof(struct xfs_parent_ptr));
+ aent = (struct xfs_attrlist_ent *)
+ &namebuf[alist->al_offset[i]];
+ xpnr = (struct xfs_parent_name_rec *)(aent->a_name);
+
+ if (aent->a_valuelen > XFS_PPTR_MAXNAMELEN) {
+ error = -EFSCORRUPTED;
+ goto out_unlock;
+ }
+ name_len = aent->a_valuelen;
+
+ args.name = (char *)xpnr;
+ args.hashval = xfs_da_hashname(args.name, args.namelen),
+ args.value = (unsigned char *)(xpp->xpp_name);
+ args.valuelen = name_len;
+
+ error = xfs_attr_get_ilocked(&args);
+ error = (error == -EEXIST ? 0 : error);
+ if (error) {
+ error = -EFSCORRUPTED;
+ goto out_unlock;
+ }
+
+ xfs_init_parent_ptr(xpp, xpnr);
+ if (!xfs_verify_ino(args.dp->i_mount, xpp->xpp_ino)) {
+ error = -EFSCORRUPTED;
+ goto out_unlock;
+ }
+ }
+ ppi->pi_ptrs_used = alist->al_count;
+ if (!alist->al_more)
+ ppi->pi_flags |= XFS_PPTR_OFLAG_DONE;
+
+ /* Update the caller with the current cursor position */
+ memcpy(&ppi->pi_cursor, &context.cursor,
+ sizeof(struct xfs_attrlist_cursor));
+
+out_unlock:
+ xfs_iunlock(ip, lock_mode);
+out_kfree:
+ kvfree(namebuf);
+
+ return error;
+}
+
diff --git a/fs/xfs/xfs_parent_utils.h b/fs/xfs/xfs_parent_utils.h
new file mode 100644
index 000000000000..ad60baee8b2a
--- /dev/null
+++ b/fs/xfs/xfs_parent_utils.h
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Oracle, Inc.
+ * All rights reserved.
+ */
+#ifndef __XFS_PARENT_UTILS_H__
+#define __XFS_PARENT_UTILS_H__
+
+int xfs_attr_get_parent_pointer(struct xfs_inode *ip,
+ struct xfs_pptr_info *ppi);
+#endif /* __XFS_PARENT_UTILS_H__ */
--
2.25.1
