On Sun, May 6, 2018 at 7:24 PM, Allison Henderson
<allison.henderson@xxxxxxxxxx> wrote:
This patch adds a new file ioctl to retrieve the parent
pointer of a given inode
Looking through the patch I spotted some typos and use of outdated
names in comments.
+#define XFS_PPTR_MAXNAMELEN 255
+
+/* return parents of the handle, not the open fd */
+#define XFS_PPTR_IFLAG_HANDLE (1U << 0)
+
+/* 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 */
+ __u32 xpp_namelen; /* File name length */
+ __u8 xpp_name[XFS_PPTR_MAXNAMELEN]; /* File name */
+};
+
+/* Iterate though an inodes parent pointers */
typo through
+struct xfs_pptr_info {
+ struct xfs_handle pi_handle;
+ struct xfs_attrlist_cursor pi_cursor;
+ __u32 pi_flags;
+ __u32 pi_reserved;
+ __u32 pi_ptrs_size;
+ __u32 pi_ptrs_used;
+ __u64 pi_reserved2[6];
+
+ /*
+ * An array of struct xfs_pptr follows the header
Should be struct xfs_parent_ptr
+ * information. Use XFS_PPINFO_TO_PP() to access the
+ * parent pointer array entries.
+ */
+};
+
+#define XFS_PPTR_INFO_SIZEOF(nr_ptrs) sizeof (struct xfs_pptr_info) + \
+ nr_ptrs * sizeof(struct xfs_parent_ptr)
+
+#define XFS_PPINFO_TO_PP(info, idx) \
+ (&(((struct xfs_parent_ptr *)((char *)(info) + sizeof(*(info))))[(idx)]))
+
/*
* ioctl limits
*/
@@ -596,6 +633,7 @@ 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_GETPPOINTER _IOR ('X', 61, 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 e6de97c..61f1961 100644
--- a/fs/xfs/libxfs/xfs_parent.c
+++ b/fs/xfs/libxfs/xfs_parent.c
@@ -32,6 +32,16 @@
#include "xfs_attr_sf.h"
#include "xfs_bmap.h"
+/* Initializes a xfs_parent_ptr from an xfs_parent_name_rec */
+void
+xfs_init_parent_ptr(struct xfs_parent_ptr *xpp,
+ 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 298562b..1a321db 100644
--- a/fs/xfs/libxfs/xfs_parent.h
+++ b/fs/xfs/libxfs/xfs_parent.h
@@ -33,4 +33,6 @@ int xfs_parent_add(struct xfs_trans *tp, struct xfs_inode *parent,
struct xfs_inode *child, struct xfs_name *child_name,
uint32_t diroffset, xfs_fsblock_t *firstblock,
struct xfs_defer_ops *dfops);
+void xfs_init_parent_ptr(struct xfs_parent_ptr *xpp,
+ struct xfs_parent_name_rec *rec);
#endif /* __XFS_PARENT_H__ */
diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
index 3e59a34..bdbe9fb 100644
--- a/fs/xfs/xfs_attr_list.c
+++ b/fs/xfs/xfs_attr_list.c
@@ -581,6 +581,9 @@ xfs_attr_put_listent(
if (((context->flags & ATTR_ROOT) == 0) !=
((flags & XFS_ATTR_ROOT) == 0))
return;
+ if (((context->flags & ATTR_PARENT) == 0) !=
+ ((flags & XFS_ATTR_PARENT) == 0))
+ return;
arraytop = sizeof(*alist) +
context->count * sizeof(alist->al_offset[0]);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 844480a..ee544f2 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -46,6 +46,8 @@
#include "xfs_fsmap.h"
#include "scrub/xfs_scrub.h"
#include "xfs_sb.h"
+#include "xfs_da_format.h"
+#include "xfs_parent_utils.h"
#include <linux/capability.h>
#include <linux/cred.h>
@@ -1738,6 +1740,62 @@ xfs_ioc_scrub_metadata(
return 0;
}
+/*
+ * IOCTL routine to get the parent pointer of an inode and return it to user
+ * space. Caller must pass an struct xfs_parent_name_irec with a name buffer
+ * large enough to hold the file name. Returns 0 on success or non-zero on
+ * failure
+ */
xfs_parent_name_irec should be xfs_pptr_info
+STATIC int
+xfs_ioc_get_parent_pointer(
+ struct file *filp,
+ void __user *arg)
+{
+ struct xfs_inode *ip;
+ struct xfs_pptr_info *ppi;
+ struct dentry *dentry;
+ int error = 0;
+
+ /* Allocate an xfs_pptr_info to put the user data */
+ ppi = kmem_alloc(sizeof(struct xfs_pptr_info), KM_SLEEP);
+ if (!ppi)
+ return -ENOMEM;
+
+ /* Copy the data from the user */
+ copy_from_user(ppi, arg, sizeof(struct xfs_pptr_info));
+
+ /*
+ * Now that we know how big the trailing buffer is, expand
+ * our kernel xfs_pptr_info to be the same size
+ */
+ ppi = kmem_realloc(ppi, XFS_PPTR_INFO_SIZEOF(ppi->pi_ptrs_size),
+ KM_SLEEP);
+ if (!ppi)
+ return -ENOMEM;
+
+ if (ppi->pi_flags == XFS_PPTR_IFLAG_HANDLE) {
+ dentry = xfs_handle_to_dentry(filp, &ppi->pi_handle,
+ sizeof(struct xfs_handle));
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ ip = XFS_I(d_inode(dentry));
+ } else
+ ip = XFS_I(file_inode(filp));
+
+ /* Get the parent pointers */
+ error = xfs_attr_get_parent_pointer(ip, ppi);
+
+ if (error)
+ goto out;
+
+ /* Copy the parent pointers back to the user */
+ copy_to_user(arg, ppi, XFS_PPTR_INFO_SIZEOF(ppi->pi_ptrs_size));
+
+out:
+ kmem_free(ppi);
+ return error;
+}
+
int
xfs_ioc_swapext(
xfs_swapext_t *sxp)
@@ -1894,7 +1952,8 @@ xfs_file_ioctl(
return xfs_ioc_getxflags(ip, arg);
case XFS_IOC_SETXFLAGS:
return xfs_ioc_setxflags(ip, filp, arg);
-
+ case XFS_IOC_GETPPOINTER:
+ return xfs_ioc_get_parent_pointer(filp, arg);
case XFS_IOC_FSSETDM: {
struct fsdmidata dmi;
diff --git a/fs/xfs/xfs_parent_utils.c b/fs/xfs/xfs_parent_utils.c
index 0fd48b8..1df003a 100644
--- a/fs/xfs/xfs_parent_utils.c
+++ b/fs/xfs/xfs_parent_utils.c
@@ -68,3 +68,69 @@ xfs_parent_remove_deferred(
ATTR_PARENT);
}
+/*
+ * 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 attrlist *alist;
+ struct attrlist_ent *aent;
+ struct xfs_parent_ptr *xpp;
+ struct xfs_parent_name_rec *xpnr;
+ char *namebuf;
+ unsigned int namebuf_size;
+ int name_len;
+ int error = 0;
+ unsigned int flags = ATTR_PARENT;
+ int i;
+
+ /* Allocate a buffer to store the attribute names */
+ namebuf_size = sizeof(struct attrlist) +
+ (ppi->pi_ptrs_size) * sizeof(struct attrlist_ent);
+ namebuf = kmem_zalloc_large(namebuf_size, KM_SLEEP);
+ if (!namebuf)
+ return -ENOMEM;
+
+ error = xfs_attr_list(ip, namebuf, namebuf_size, flags,
+ (attrlist_cursor_kern_t *)&ppi->pi_cursor);
+ if (error)
+ goto out_kfree;
+
+ alist = (struct attrlist *)namebuf;
+
+ for (i = 0; i < alist->al_count; i++) {
+ xpp = XFS_PPINFO_TO_PP(ppi, i);
+ memset(xpp, 0, sizeof(struct xfs_parent_ptr));
+ aent = (struct attrlist_ent *) &namebuf[alist->al_offset[i]];
+ xpnr = (struct xfs_parent_name_rec *)(aent->a_name);
+
+ if (aent->a_valuelen > XFS_PPTR_MAXNAMELEN) {
+ error = -ERANGE;
+ goto out_kfree;
+ }
+
+ name_len = aent->a_valuelen;
+ error = xfs_attr_get(ip, (char *)xpnr,
+ sizeof(struct xfs_parent_name_rec),
+ (unsigned char *)(xpp->xpp_name),
+ &name_len, flags);
+ if (error)
+ goto out_kfree;
+
+ xpp->xpp_namelen = name_len;
+ xfs_init_parent_ptr(xpp, xpnr);
+ }
+ ppi->pi_ptrs_used = alist->al_count;
+
+out_kfree:
+ kmem_free(namebuf);
+
+ return error;
+}
+
diff --git a/fs/xfs/xfs_parent_utils.h b/fs/xfs/xfs_parent_utils.h
index 9e0ac13..33e3b2c 100644
--- a/fs/xfs/xfs_parent_utils.h
+++ b/fs/xfs/xfs_parent_utils.h
@@ -27,4 +27,6 @@ int xfs_parent_remove_deferred(struct xfs_inode *parent,
struct xfs_inode *child,
xfs_dir2_dataptr_t diroffset,
struct xfs_defer_ops *dfops);
+int xfs_attr_get_parent_pointer(struct xfs_inode *ip,
+ struct xfs_pptr_info *ppi);
#endif /* __XFS_PARENT_UTILS_H__ */
--
2.7.4
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