Btrfs: add search and inode lookup ioctls

The search ioctl is a generic tool for doing btree searches from
userland applications.  The first user of the search ioctl is a
subvolume listing feature, but we'll also use it to find new
files in a subvolume.

The search ioctl allows you to specify min and max keys to search for,
along with min and max transid.  It returns the items along with a
header that includes the item key.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index bc49914475eb..79c07b104f91 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -30,6 +30,68 @@ struct btrfs_ioctl_vol_args {
         char name[BTRFS_PATH_NAME_MAX + 1];
 };
 
+#define BTRFS_INO_LOOKUP_PATH_MAX 4080
+struct btrfs_ioctl_ino_lookup_args {
+        __u64 treeid;
+        __u64 objectid;
+        char name[BTRFS_INO_LOOKUP_PATH_MAX];
+};
+
+struct btrfs_ioctl_search_key {
+        /* which root are we searching.  0 is the tree of tree roots */
+        __u64 tree_id;
+
+        /* keys returned will be >= min and <= max */
+        __u64 min_objectid;
+        __u64 max_objectid;
+
+        /* keys returned will be >= min and <= max */
+        __u64 min_offset;
+        __u64 max_offset;
+
+        /* max and min transids to search for */
+        __u64 min_transid;
+        __u64 max_transid;
+
+        /* keys returned will be >= min and <= max */
+        __u32 min_type;
+        __u32 max_type;
+
+        /*
+         * how many items did userland ask for, and how many are we
+         * returning
+         */
+        __u32 nr_items;
+
+        /* align to 64 bits */
+        __u32 unused;
+
+        /* some extra for later */
+        __u64 unused1;
+        __u64 unused2;
+        __u64 unused3;
+        __u64 unused4;
+};
+
+struct btrfs_ioctl_search_header {
+        __u64 transid;
+        __u64 objectid;
+        __u64 offset;
+        __u32 type;
+        __u32 len;
+};
+
+#define BTRFS_SEARCH_ARGS_BUFSIZE (4096 - sizeof(struct btrfs_ioctl_search_key))
+/*
+ * the buf is an array of search headers where
+ * each header is followed by the actual item
+ * the type field is expanded to 32 bits for alignment
+ */
+struct btrfs_ioctl_search_args {
+        struct btrfs_ioctl_search_key key;
+        char buf[BTRFS_SEARCH_ARGS_BUFSIZE];
+};
+
 struct btrfs_ioctl_clone_range_args {
   __s64 src_fd;
   __u64 src_offset, src_length;
@@ -67,4 +129,8 @@ struct btrfs_ioctl_clone_range_args {
                                    struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_SNAP_DESTROY _IOW(BTRFS_IOCTL_MAGIC, 15, \
                                 struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_TREE_SEARCH _IOWR(BTRFS_IOCTL_MAGIC, 17, \
+                                   struct btrfs_ioctl_search_args)
+#define BTRFS_IOC_INO_LOOKUP _IOWR(BTRFS_IOCTL_MAGIC, 18, \
+                                   struct btrfs_ioctl_ino_lookup_args)
 #endif