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authorQu Wenruo <wqu@suse.com>2020-06-24 18:03:13 +0200
committerTom Rini <trini@konsulko.com>2020-09-07 21:00:36 -0400
commitf48615276b5003ba75cf136729c804590f8b63ef (patch)
tree0d9539d8e29c71ea784b2bd471f87e6d05726143 /fs
parent8098da7094b181b92e5a6fb284e161e012eca7d7 (diff)
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fs: btrfs: Introduce function to resolve the path of one subvolume
This patch introduces a new function, list_one_subvol(), which will resolve the path to FS_TREE of one subvolume. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Marek BehĂșn <marek.behun@nic.cz>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/subvolume.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/fs/btrfs/subvolume.c b/fs/btrfs/subvolume.c
index b446e72..258c3da 100644
--- a/fs/btrfs/subvolume.c
+++ b/fs/btrfs/subvolume.c
@@ -8,6 +8,7 @@
#include <malloc.h>
#include "ctree.h"
#include "btrfs.h"
+#include "disk-io.h"
/*
* Resolve the path of ino inside subvolume @root into @path_ret.
@@ -74,6 +75,86 @@ out:
return ret;
}
+static int list_one_subvol(struct btrfs_root *root, char *path_ret)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *tree_root = fs_info->tree_root;
+ struct btrfs_path path;
+ struct btrfs_key key;
+ char *tmp;
+ u64 cur = root->root_key.objectid;
+ int ret = 0;
+
+ tmp = malloc(PATH_MAX);
+ if (!tmp)
+ return -ENOMEM;
+ tmp[0] = '\0';
+ path_ret[0] = '\0';
+ btrfs_init_path(&path);
+ while (cur != BTRFS_FS_TREE_OBJECTID) {
+ struct btrfs_root_ref *rr;
+ struct btrfs_key location;
+ int name_len;
+ u64 ino;
+
+ key.objectid = cur;
+ key.type = BTRFS_ROOT_BACKREF_KEY;
+ key.offset = (u64)-1;
+ btrfs_release_path(&path);
+
+ ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
+ if (ret == 0)
+ ret = -EUCLEAN;
+ if (ret < 0)
+ goto out;
+ ret = btrfs_previous_item(tree_root, &path, cur,
+ BTRFS_ROOT_BACKREF_KEY);
+ if (ret > 0)
+ ret = -ENOENT;
+ if (ret < 0)
+ goto out;
+
+ /* Get the subvolume name */
+ rr = btrfs_item_ptr(path.nodes[0], path.slots[0],
+ struct btrfs_root_ref);
+ strncpy(tmp, path_ret, PATH_MAX);
+ name_len = btrfs_root_ref_name_len(path.nodes[0], rr);
+ if (name_len > BTRFS_NAME_LEN) {
+ ret = -ENAMETOOLONG;
+ goto out;
+ }
+ ino = btrfs_root_ref_dirid(path.nodes[0], rr);
+ read_extent_buffer(path.nodes[0], path_ret,
+ (unsigned long)(rr + 1), name_len);
+ path_ret[name_len] = '/';
+ path_ret[name_len + 1] = '\0';
+ strncat(path_ret, tmp, PATH_MAX);
+
+ /* Get the path inside the parent subvolume */
+ btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+ location.objectid = key.offset;
+ location.type = BTRFS_ROOT_ITEM_KEY;
+ location.offset = (u64)-1;
+ root = btrfs_read_fs_root(fs_info, &location);
+ if (IS_ERR(root)) {
+ ret = PTR_ERR(root);
+ goto out;
+ }
+ ret = get_path_in_subvol(root, ino, path_ret);
+ if (ret < 0)
+ goto out;
+ cur = key.offset;
+ }
+ /* Add the leading '/' */
+ strncpy(tmp, path_ret, PATH_MAX);
+ strncpy(path_ret, "/", PATH_MAX);
+ strncat(path_ret, tmp, PATH_MAX);
+out:
+ btrfs_release_path(&path);
+ free(tmp);
+ return ret;
+}
+
static int get_subvol_name(u64 subvolid, char *name, int max_len)
{
struct btrfs_root_ref rref;