2 * Copyright (C) 2010 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
20 #include <sys/ioctl.h>
21 #include <sys/mount.h>
26 #include <sys/types.h>
32 #include "kerncompat.h"
34 #include "transaction.h"
38 /* we store all the roots we find in an rbtree so that we can
39 * search for them later.
46 * one of these for each root we find.
49 struct rb_node rb_node;
54 /* the id of the root that references this one */
57 /* the dir id we're in from ref_tree */
60 /* path from the subvol we live in to this root, including the
61 * root's name. This is null until we do the extra lookup ioctl.
65 /* the name of this root in the directory it lives in */
69 void root_lookup_init(struct root_lookup *tree)
71 tree->root.rb_node = NULL;
74 static int comp_entry(struct root_info *entry, u64 root_id, u64 ref_tree)
76 if (entry->root_id > root_id)
78 if (entry->root_id < root_id)
80 if (entry->ref_tree > ref_tree)
82 if (entry->ref_tree < ref_tree)
88 * insert a new root into the tree. returns the existing root entry
89 * if one is already there. Both root_id and ref_tree are used
92 static struct rb_node *tree_insert(struct rb_root *root, u64 root_id,
93 u64 ref_tree, struct rb_node *node)
95 struct rb_node ** p = &root->rb_node;
96 struct rb_node * parent = NULL;
97 struct root_info *entry;
102 entry = rb_entry(parent, struct root_info, rb_node);
104 comp = comp_entry(entry, root_id, ref_tree);
114 entry = rb_entry(parent, struct root_info, rb_node);
115 rb_link_node(node, parent, p);
116 rb_insert_color(node, root);
121 * find a given root id in the tree. We return the smallest one,
122 * rb_next can be used to move forward looking for more if required
124 static struct root_info *tree_search(struct rb_root *root, u64 root_id)
126 struct rb_node * n = root->rb_node;
127 struct root_info *entry;
130 entry = rb_entry(n, struct root_info, rb_node);
132 if (entry->root_id < root_id)
134 else if (entry->root_id > root_id)
137 struct root_info *prev;
138 struct rb_node *prev_n;
143 prev = rb_entry(prev_n, struct root_info,
145 if (prev->root_id != root_id)
157 * helper to open either a file or directory so that
158 * we can run ioctls on it.
160 static int open_file_or_dir(const char *fname)
167 ret = stat(fname, &st);
172 if (S_ISDIR(st.st_mode)) {
173 dirstream = opendir(fname);
178 fd = dirfd(dirstream);
180 fd = open(fname, O_RDWR);
190 * this allocates a new root in the lookup tree.
192 * root_id should be the object id of the root
194 * ref_tree is the objectid of the referring root.
196 * dir_id is the directory in ref_tree where this root_id can be found.
198 * name is the name of root_id in that directory
200 * name_len is the length of name
202 static int add_root(struct root_lookup *root_lookup,
203 u64 root_id, u64 ref_tree, u64 dir_id, char *name,
206 struct root_info *ri;
208 ri = malloc(sizeof(*ri) + name_len);
210 printf("memory allocation failed\n");
215 ri->root_id = root_id;
216 ri->ref_tree = ref_tree;
217 strncpy(ri->name, name, name_len);
219 ret = tree_insert(&root_lookup->root, root_id, ref_tree, &ri->rb_node);
221 printf("failed to insert tree %llu\n", (unsigned long long)root_id);
228 * for a given root_info, search through the root_lookup tree to construct
229 * the full path name to it.
231 * This can't be called until all the root_info->path fields are filled
232 * in by lookup_ino_path
234 static int resolve_root(struct root_lookup *rl, struct root_info *ri)
237 char *full_path = NULL;
239 struct root_info *found;
242 * we go backwards from the root_info object and add pathnames
243 * from parent directories as we go.
249 int add_len = strlen(found->path);
251 /* room for / and for null */
252 tmp = malloc(add_len + 2 + len);
254 memcpy(tmp + add_len + 1, full_path, len);
256 memcpy(tmp, found->path, add_len);
257 tmp [add_len + len + 1] = '\0';
262 full_path = strdup(found->path);
266 next = found->ref_tree;
267 /* if the ref_tree refers to ourselves, we're at the top */
268 if (next == found->root_id) {
274 * if the ref_tree wasn't in our tree of roots, we're
277 found = tree_search(&rl->root, next);
283 printf("ID %llu top level %llu path %s\n", ri->root_id, top_id,
290 * for a single root_info, ask the kernel to give us a path name
291 * inside it's ref_root for the dir_id where it lives.
293 * This fills in root_info->path with the path to the directory and and
294 * appends this root's name.
296 static int lookup_ino_path(int fd, struct root_info *ri)
298 struct btrfs_ioctl_ino_lookup_args args;
304 args.treeid = ri->ref_tree;
305 args.objectid = ri->dir_id;
308 ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
310 fprintf(stderr, "Failed to lookup path for root %llu\n",
311 (unsigned long long)ri->ref_tree);
317 * we're in a subdirectory of ref_tree, the kernel ioctl
318 * puts a / in there for us
320 ri->path = malloc(strlen(ri->name) + strlen(args.name) + 1);
322 perror("malloc failed");
325 strcpy(ri->path, args.name);
326 strcat(ri->path, ri->name);
328 /* we're at the root of ref_tree */
329 ri->path = strdup(ri->name);
331 perror("strdup failed");
338 static int list_subvols(int fd)
340 struct root_lookup root_lookup;
343 struct btrfs_ioctl_search_args args;
344 struct btrfs_ioctl_search_key *sk = &args.key;
345 struct btrfs_ioctl_search_header *sh;
346 struct btrfs_root_ref *ref;
347 unsigned long off = 0;
353 root_lookup_init(&root_lookup);
355 memset(&args, 0, sizeof(args));
357 /* search in the tree of tree roots */
361 * set the min and max to backref keys. The search will
362 * only send back this type of key now.
364 sk->max_type = BTRFS_ROOT_BACKREF_KEY;
365 sk->min_type = BTRFS_ROOT_BACKREF_KEY;
368 * set all the other params to the max, we'll take any objectid
371 sk->max_objectid = (u64)-1;
372 sk->max_offset = (u64)-1;
373 sk->max_transid = (u64)-1;
375 /* just a big number, doesn't matter much */
379 ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
384 /* the ioctl returns the number of item it found in nr_items */
385 if (sk->nr_items == 0)
391 * for each item, pull the key out of the header and then
392 * read the root_ref item it contains
394 for (i = 0; i < sk->nr_items; i++) {
395 sh = (struct btrfs_ioctl_search_header *)(args.buf +
399 ref = (struct btrfs_root_ref *)(args.buf + off);
400 name_len = btrfs_stack_root_ref_name_len(ref);
401 name = (char *)(ref + 1);
402 dir_id = btrfs_stack_root_ref_dirid(ref);
404 add_root(&root_lookup, sh->objectid, sh->offset,
405 dir_id, name, name_len);
410 * record the mins in sk so we can make sure the
411 * next search doesn't repeat this root
413 sk->min_objectid = sh->objectid;
414 sk->min_type = sh->type;
415 sk->min_offset = sh->offset;
418 /* this iteration is done, step forward one root for the next
421 if (sk->min_objectid < (u64)-1)
427 * now we have an rbtree full of root_info objects, but we need to fill
428 * in their path names within the subvol that is referencing each one.
430 n = rb_first(&root_lookup.root);
432 struct root_info *entry;
433 entry = rb_entry(n, struct root_info, rb_node);
434 lookup_ino_path(fd, entry);
438 /* now that we have all the subvol-relative paths filled in,
439 * we have to string the subvols together so that we can get
440 * a path all the way back to the FS root
442 n = rb_last(&root_lookup.root);
444 struct root_info *entry;
445 entry = rb_entry(n, struct root_info, rb_node);
446 resolve_root(&root_lookup, entry);
450 printf("%s\n", BTRFS_BUILD_VERSION);
454 int main(int ac, char **av)
459 fprintf(stderr, "usage: btrfs-list mount_point\n");
462 fd = open_file_or_dir(av[1]);
464 return list_subvols(fd);