From: Darrick J. Wong <djwong@xxxxxxxxxx>
Source kernel commit: 233f4e12bbb2c5fb1588b857336a26e8bb6942af
This patch adds a pair of new file ioctls to retrieve the parent pointer
of a given inode. They both return the same results, but one operates
on the file descriptor passed to ioctl() whereas the other allows the
caller to specify a file handle for which the caller wants results.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
libxfs/xfs_fs.h | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_ondisk.h | 5 +++
libxfs/xfs_parent.c | 34 +++++++++++++++++++++++
libxfs/xfs_parent.h | 5 +++
4 files changed, 118 insertions(+)
diff --git a/libxfs/xfs_fs.h b/libxfs/xfs_fs.h
index 97384ab95..ea654df05 100644
--- a/libxfs/xfs_fs.h
+++ b/libxfs/xfs_fs.h
@@ -816,6 +816,78 @@ struct xfs_exchange_range {
XFS_EXCHANGE_RANGE_DRY_RUN | \
XFS_EXCHANGE_RANGE_FILE1_WRITTEN)
+/* Iterating parent pointers of files. */
+
+/* target was the root directory */
+#define XFS_GETPARENTS_OFLAG_ROOT (1U << 0)
+
+/* Cursor is done iterating pptrs */
+#define XFS_GETPARENTS_OFLAG_DONE (1U << 1)
+
+#define XFS_GETPARENTS_OFLAGS_ALL (XFS_GETPARENTS_OFLAG_ROOT | \
+ XFS_GETPARENTS_OFLAG_DONE)
+
+#define XFS_GETPARENTS_IFLAGS_ALL (0)
+
+struct xfs_getparents_rec {
+ struct xfs_handle gpr_parent; /* Handle to parent */
+ __u32 gpr_reclen; /* Length of entire record */
+ __u32 gpr_reserved; /* zero */
+ char gpr_name[]; /* Null-terminated filename */
+};
+
+/* Iterate through this file's directory parent pointers */
+struct xfs_getparents {
+ /*
+ * 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 gp_cursor;
+
+ /* Input flags: XFS_GETPARENTS_IFLAG* */
+ __u16 gp_iflags;
+
+ /* Output flags: XFS_GETPARENTS_OFLAG* */
+ __u16 gp_oflags;
+
+ /* Size of the gp_buffer in bytes */
+ __u32 gp_bufsize;
+
+ /* Must be set to zero */
+ __u64 gp_reserved;
+
+ /* Pointer to a buffer in which to place xfs_getparents_rec */
+ __u64 gp_buffer;
+};
+
+static inline struct xfs_getparents_rec *
+xfs_getparents_first_rec(struct xfs_getparents *gp)
+{
+ return (struct xfs_getparents_rec *)(uintptr_t)gp->gp_buffer;
+}
+
+static inline struct xfs_getparents_rec *
+xfs_getparents_next_rec(struct xfs_getparents *gp,
+ struct xfs_getparents_rec *gpr)
+{
+ void *next = ((void *)gpr + gpr->gpr_reclen);
+ void *end = (void *)(uintptr_t)(gp->gp_buffer + gp->gp_bufsize);
+
+ if (next >= end)
+ return NULL;
+
+ return next;
+}
+
+/* Iterate through this file handle's directory parent pointers. */
+struct xfs_getparents_by_handle {
+ /* Handle to file whose parents we want. */
+ struct xfs_handle gph_handle;
+
+ struct xfs_getparents gph_request;
+};
+
/*
* ioctl commands that are used by Linux filesystems
*/
@@ -851,6 +923,8 @@ struct xfs_exchange_range {
/* 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_getparents)
+#define XFS_IOC_GETPARENTS_BY_HANDLE _IOWR('X', 63, struct xfs_getparents_by_handle)
/*
* ioctl commands that replace IRIX syssgi()'s
diff --git a/libxfs/xfs_ondisk.h b/libxfs/xfs_ondisk.h
index 25952ef58..e8cdd77d0 100644
--- a/libxfs/xfs_ondisk.h
+++ b/libxfs/xfs_ondisk.h
@@ -156,6 +156,11 @@ 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_getparents_rec, 32);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_getparents, 40);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_getparents_by_handle, 64);
+
/*
* The v5 superblock format extended several v4 header structures with
* additional data. While new fields are only accessible on v5
diff --git a/libxfs/xfs_parent.c b/libxfs/xfs_parent.c
index a53b7d13d..bb0465197 100644
--- a/libxfs/xfs_parent.c
+++ b/libxfs/xfs_parent.c
@@ -254,3 +254,37 @@ xfs_parent_replacename(
xfs_attr_defer_add(&ppargs->args, XFS_ATTR_DEFER_REPLACE);
return 0;
}
+
+/*
+ * Extract parent pointer information from any parent pointer xattr into
+ * @parent_ino/gen. The last two parameters can be NULL pointers.
+ *
+ * Returns 0 if this is not a parent pointer xattr at all; or -EFSCORRUPTED for
+ * garbage.
+ */
+int
+xfs_parent_from_attr(
+ struct xfs_mount *mp,
+ unsigned int attr_flags,
+ const unsigned char *name,
+ unsigned int namelen,
+ const void *value,
+ unsigned int valuelen,
+ xfs_ino_t *parent_ino,
+ uint32_t *parent_gen)
+{
+ const struct xfs_parent_rec *rec = value;
+
+ ASSERT(attr_flags & XFS_ATTR_PARENT);
+
+ if (!xfs_parent_namecheck(attr_flags, name, namelen))
+ return -EFSCORRUPTED;
+ if (!xfs_parent_valuecheck(mp, value, valuelen))
+ return -EFSCORRUPTED;
+
+ if (parent_ino)
+ *parent_ino = be64_to_cpu(rec->p_ino);
+ if (parent_gen)
+ *parent_gen = be32_to_cpu(rec->p_gen);
+ return 0;
+}
diff --git a/libxfs/xfs_parent.h b/libxfs/xfs_parent.h
index 768633b31..d7ab09e73 100644
--- a/libxfs/xfs_parent.h
+++ b/libxfs/xfs_parent.h
@@ -91,4 +91,9 @@ int xfs_parent_replacename(struct xfs_trans *tp,
struct xfs_inode *new_dp, const struct xfs_name *new_name,
struct xfs_inode *child);
+int xfs_parent_from_attr(struct xfs_mount *mp, unsigned int attr_flags,
+ const unsigned char *name, unsigned int namelen,
+ const void *value, unsigned int valuelen,
+ xfs_ino_t *parent_ino, uint32_t *parent_gen);
+
#endif /* __XFS_PARENT_H__ */
